Precision Chemical Design for Reticular Spintronics

Abstract

The development of spin functionalities depends critically on magnetic materials in which spin states, exchange pathways, and transport properties can be precisely engineered at the atomic level. Reticular chemistry provides a modular and programmable platform to meet this need by enabling rigorous control over the composition, connectivity, and topology within periodic frameworks. At the intersection of these two fields, reticular spintronics exploits chemical precision to systematically modulate spin-active centers and exchange interactions while incorporating stimuli-responsive components for dynamic control. In this review, we discuss how reticular architectures can translate molecular design principles into tunable spintronic behaviors in metal–organic frameworks (MOFs) and covalent organic frameworks (COFs) to highlight complementary design features. By linking microscopic coordination chemistry to macroscopic spin phenomena, these frameworks offer a versatile route to predictable control over spin-polarized transport and collective magnetism. These insights establish a design-oriented framework for engineering spin in reticular framework-based systems and guide the development of chemically programmable spin materials.

1. Introduction

Spintronics exploits the electron’s spin degree of freedom, in addition to its charge, to enable new modes for information storage, processing, and transmission. − Compared with purely charge-based electronics that dissipate energy through Joule heat, spintronics aims to achieve energy efficiency, nonvolatility, and ultrafast operation by manipulating spin alignment and spin currents. The discovery of tunneling magnetoresistance (TMR) and giant magnetoresistance (GMR) , initiated the spintronics era, underpinned the dramatic increase in hard disk storage density, and modern read-head technologies. Subsequent exploitation of spin-dependent phenomena, such as spin-transfer torque, spin–orbit coupling (SOC), and the family of Hall effects, − has broadened the landscape of spin-based functionalities, laying the groundwork for low-power logic, neuromorphic devices, and quantum information technologies.

Realizing these opportunities requires materials that support robust spin alignment, tunable exchange interactions, and long spin coherence. Magnetic materials are therefore central to spintronics. , Traditional inorganic magnets and layered heterostructures have yielded seminal insights into spin-dependent transport and magnetism, − yet their limited compositional flexibility and structural rigidity restrict systematic tuning of spin and electronic properties. To progress toward scalable and adaptive spintronic architectures, a new class of materials is needed that combines atomic-level designability, molecular programmability, chemical diversity, and electronic flexibility within a unified framework.

Reticular chemistry provides such a platform by offering a precise inverse-design strategy for assembling extended solids from molecular building blocks. − Its power lies in the ability to precisely encode electronic and magnetic functions directly into a lattice through rational chemical design. By tuning coordination geometries, ligand fields, and π-conjugation, reticular chemistry can modulate electronic structures, exchange interactions, and magnetic anisotropy across an extended framework. The inherent porosity and structural flexibility of reticular materials further facilitate integration of responsive elements, allowing external control of spin states via photo-, electro-, magneto-, mechano-, and chemical stimuli. − This combination of atomic and molecular precision with predictive design positions reticular frameworks as a versatile foundation to guide the rational design of spintronic and quantum technologies. −

Reticular spintronics thus emerges as a conceptual framework that integrates spintronic functionality into reticular architectures through chemically encoded design principles. Rather than treating magnetism and spin transport as incidental byproducts, reticular spintronics regards spin degrees of freedom as design variables that can be intentionally programmed at the level of building blocks and propagated through the lattice. This strategy emphasizes the translation of local electronic and magnetic characteristics into collective spin behavior governed by lattice symmetry, topology, and connectivity. By unifying coordination chemistry, molecular electronics, and spin physics within a single design language, reticular spintronics establishes a systematic route to engineer spin networks whose properties are predictable, tunable, and scalable across length scales.

The assembly of chemical building blocks into crystalline frameworks is exemplified by metal–organic frameworks (MOFs) − and covalent organic frameworks (COFs). − Their modularity of composition and connectivity enable systematic control over spin-active centers, their spatial arrangements, and coupling pathways, thereby transforming the engineering of magnetic and spintronic functionalities. Magnetic moments can be embedded on metal nodes, organic ligands, or radical units, while the framework topology fixes dimensionality and spin network connectivity, providing a level of modular control to engineer designable frustration, band topology, and magnetic ground states, a feat rarely attainable in conventional inorganic solids.

This review discusses how the precise and modular nature of reticular chemistry enables rational theoretical design of spin networks in reticular frameworks. Deliberate control over framework composition, connectivity, and topology allows systematic tuning of spin interactions and network architectures, opening opportunities to investigate collective spin phenomena and encode programmable spin functionalities. The discussion emphasizes chemical precision in magnetic design, the integration of responsive elements, and hierarchical principles that link microscopic chemistry to the emergent spin behavior. These principles provide a roadmap for developing next-generation spintronic and quantum materials with tunable, programmable, and precisely engineered functionalities.

2. Precision Design of Spin Networks

Reticular chemistry implements a bottom-up strategy in which atoms, ions, clusters, and organic molecules are assembled into extended, periodic, and crystalline networks through robust chemical bonds. ,, This modular approach confines structural growth within a defined crystallographic framework, leading to predictable and tunable architectures. Achieving precision in both structure and function rests on two interrelated elements.

• Intrinsic nature of building blocks , including their geometry (e.g., sizes, shapes, bond lengths, and angles), symmetry (e.g., point groups and distribution of bonding sites), chemical composition (e.g., metal ions, clusters, and organic linkers), coordination preferences, and electronic properties, define the spatial arrangement and functional landscape of the frameworks (Figure a,b). These attributes govern topology, porosity, and physicochemical properties, and they set the stage for local spin states and magnetic anisotropy.

• Bonding modes and directional connectivity between these units , including coordination, covalent, and hydrogen bonds, determine the dimensionality and topology of the frameworks, as well as the pathways for spin communication (Figure c–e). Connectivity dictates structural stability, crystallinity, and dynamic response while also programming the directionality of spin alignment across the lattice. For spintronic applications, the design of reticular networks therefore focuses not only on structural aspects but also on the spatial arrangement of spin centers, their exchange pathways, and their accessibility for postsynthetic modification, providing a foundation for chemically precise spin manipulation.

1.

Precision design of spin networks through reticular chemistry. (a) Atomic-scale spins arising from unpaired electrons in metal ions, clusters, and superatomic units. (b) Molecular-scale spin centers serving as tunable and switchable building blocks, including organic radicals and π-conjugated open-shell molecules. (c) Structural precision achieved by controlling coordination numbers (n-c) and representative topologies in reticular frameworks with diverse connectivity, dimensionality, and transitivity. (d) Spin symmetries that unify spatial and spin transformations in real-space and spin-space, respectively, providing a group-theoretical framework to classify distinct magnetic states. (e) Representative spin-exchange mechanisms and magnetic anisotropy in reticular materials.

2.1. Atomic-Scale Spin Centers

Electron spin originates from its intrinsic angular momentum, characterized by the spin quantum number s and spin operator S ^ = (Ŝ _x , Ŝ _y , Ŝ _z ), which obeys angular momentum algebra with eigenvalue S ^² = s(s + 1)ℏ ². For an electron (s = 1/2), the quantized projections yield spin-up (|↑⟩, + ℏ/2) and spin-down (|↓⟩, – ℏ/2) states, each carrying a magnetic moment μ _s = – g _e μ_B S ^/ℏ, where g _e ≈ 2.0023 denotes the electron g-factor, and μ_B is the Bohr magneton. This coupling between spin and magnetic moment underlines the Zeeman effect and the microscopic origin of magnetism. In atoms, spin couples to orbital angular momentum L ^ through relativistic SOC, described as H _SO = ξ­(r) L ^· S ^, lifting orbital degeneracies and correlating spatial distributions with spin orientations. The resulting total angular momentum J ^ = L ^ + S ^ governs magnetic and spectroscopic signatures, particularly in transition-metal and lanthanide ions with partially filled d and f shells hosting unpaired electrons.

For atoms and ions with unpaired electrons (Figure a), the total spin S provides a fundamental descriptor of local magnetism. Hund’s rules, ligand field effects, and SOC together generate a rich set of spin states and anisotropies. In transition-metal ions, crystal-field splitting controls orbital occupancy and thus accessible multiplets and magnetic anisotropy. In lanthanide ions, strong SOC and weak ligand fields produce highly anisotropic moments arising from well-defined J multiplets, enabling large anisotropies and slow relaxation of magnetization.

Beyond single ions, metal clusters function as collective atomic-scale spin units in which intracluster exchange interactions define an effective total spin and anisotropy. Their spin ground states depend on electronic structure and cluster geometry, and they can be embedded into reticular frameworks as well-defined nodes carrying high-spin states or anisotropic moments. , Superatoms, nanoscale entities exhibiting discrete electronic shells, offer an additional class of “artificial atoms” with tunable magnetic moments, particularly in transition-metal-doped systems. − Such superatomic building blocks bridge atomic precision and mesoscale tunability, providing chemically addressable spin centers that are compatible with reticular assembly.

2.2. Molecular-Scale Spin Centers

At the molecular level, magnetic moments arise from unpaired electrons in discrete but electronically coupled frameworks, where covalent bonding, ligand fields, and π-conjugation collectively shape the spin landscape (Figure b). − Molecular systems introduce additional design variables, such as bonding topology, electronic delocalization, and redox flexibility, which can be exploited to control spin configurations and magnetic responses.

A canonical class of molecular spin centers comprises intrinsic spin-active molecules such as organic radicals and transition-metal complexes. In organic radicals, π-type molecular orbitals host single unpaired electrons, yielding tunable spin density via substitution, conjugation length, and heteroatom incorporation. , Delocalization of spin over the π-framework stabilizes the radical and mediates magnetic exchange through π-overlap, thereby linking molecular geometry directly to spin coupling. Coordination to redox-active metal centers further extends spin delocalization, − with ligand-field strength and coordination geometry controlling spin distribution, anisotropy, and bistability. −

Beyond localized spin-active centers, π-conjugated spin frameworks form another class of molecular spin systems capable of forming extended reticular architectures. In these molecules, spin polarization spreads across conjugated backbones or aromatic lattices, giving rise to collective open-shell character and long-range magnetic coherence. Triangulene derivatives, − porphyrin and phthalocyanine arrays, − and graphene nanoribbon segments − exemplify modular π-spin units for framework assembly. In such systems, the interplay between aromatic stabilization and exchange-driven spin splitting determines whether the ground state adopts a closed-shell singlet, an open-shell singlet, or a triplet configuration. Chemical control over π-topology, edge termination, and heteroatom substitution enables tuning of electronic configurations and spin-exchange pathways. ,, These conjugated architectures provide routes to lightweight, metal-free spintronic materials in which magnetism, charge transport, and structural modularity are inherently integrated.

Molecular spin centers also support diverse stimuli-responsive spin behaviors. Spin-crossover (SCO) complexes can switch between low-spin and high-spin states in response to thermal, photonic, mechanical, electromagnetic, or chemical stimuli, − ,, while organic or metal–ligand radicals can undergo spin-state changes through redox processes or photochemical reactions. Protonation and tautomerization modulate electronic structures and can convert closed-shell and open-shell configurations. − These dynamic responses illustrate how molecular spin centers integrate structural control with functional reconfigurability, a key asset for reticular spintronics.

2.3. From Building Blocks to Spin Architectures

The transition from discrete atomic and molecular spin centers to extended spin architectures is a central theme in molecular magnetism and quantum materials chemistry. Spinful units act as programmable nodes, whose geometric connectivity and exchange interactions give rise to emergent magnetic and quantum functionalities. In reticular chemistry, these nodes can be embedded in well-defined coordination environments and linked through topologically constrained networks so that local spin properties propagate into lattice-level behavior.

The coordination geometry and connectivity of the spin centers (Figure c) govern the accessible topologies, from two-dimensional (2D) lattices (e.g., square, honeycomb, kagome, and hexagonal networks) to three-dimensional (3D) frameworks (e.g., diamond, cubic, and other extended motifs). Each topology has characteristic building-block symmetry and transitivity, defining dimensionality, spin connectivity, and exchange pathways. ,,,

• Dimensionality . Dimensionality defines the spatial extent of periodic propagation. 2D frameworks extend mainly within a plane, forming layered or sheet-like structures with limited out-of-plane freedom, whereas 3D frameworks propagate along all three spatial axes, enabling higher connectivity and more extensive pathways for magnetic, electronic, and transport interactions.

• Connectivity . Connectivity (n-c) describes how many neighboring units each building block is linked to within the framework. It does not uniquely determine dimensionality or symmetry since building blocks with the same connectivity can generate distinct geometries and topologies. For example, a 4-c node may form square-planar (D _4h ) or rectangular (D _2h ) motifs in 2D or tetrahedral (T _d ) motifs in 3D. Conversely, nodes with identical point group symmetry may also have different connectivities (e.g., O _h with 6-c, 8-c, or 12-c). ,

• Transitivity . Transitivity describes topological uniformity uniformly through the number of symmetrically distinct vertices (p), edges (q), faces (r), and tiles (s): [pqr] for 2D and [pqrs] for 3D. Regular nets with [111] or [1111] transitivity are highly symmetric, whereas higher transitivity reflects increasing structural complexity with multiple inequivalent building units.

• Tiling. Tiling mathematically describes how space is periodically partitioned into polygons in 2D or polyhedra in 3D without gaps or overlaps. In 2D, tiling is also referred to as tessellation. Tiling provides a geometry-based language for comparing reticular topologies independent of chemical composition. In 2D, vertex symbols describe polygons surrounding each node (e.g., 4.4.4.4 for sql and 3.6.3.6 for kgm), whereas in 3D, the notation [p ^m .q ⁿ ···] denotes polyhedral cells including m faces with p edges, n faces with q edges, etc. Coefficients in front of cages indicate the proportion of each tiling type.

The collective spin arrangement is constrained by the symmetry operations of the underlying magnetic and spin groups, which unifies transformations in both real and spin space (Figure d). − Each spin configuration corresponds to a specific combination of spatial and spin-space symmetries that fixes the allowed orientations, degeneracies, and possible magnetic phase transitions. This symmetry-based description provides a common language for conventional collinear and noncollinear arrangements, chiral textures, and altermagnetic states, and for understanding phenomena such as canting, magnetoelectric coupling, and topological magnetism. ,, Furthermore, the recently proposed oriented spin space group (OSSG) theory extends the spin space group framework by explicitly fixing the orientation of the spin frame relative to the crystal lattice, thereby bridging the symmetry descriptions of spin groups and magnetic groups. This formalism captures the symmetry-breaking pathway induced by SOC and provides a unified description of magnetic geometry and SOC-driven phenomena, including weak ferromagnetism, anomalous Hall responses, and spin–orbit magnetism.

Within these symmetry constraints, interactions among local spins give rise to several fundamental magnetic coupling mechanisms that define the behavior of reticular spin frameworks (Figure e). Direct exchange arises from spatial overlap of spin-bearing orbitals and depends sensitively on orbital orientation and occupancy. , In most reticular materials, superexchange via bridging ligands dominates and can be tuned through bond angles, conjugation pathways, ligand electronics, and metal–ligand covalency. , In mixed-valence architectures, double exchange links electron transport to spin alignment and can yield metallic or half-metallic states. ,

Geometric constraints and competing exchange pathways can stabilize noncollinear spin arrangements, including canted and spiral configurations. When SOC operates in a lattice lacking inversion (P) symmetry, antisymmetric Dzyaloshinskii-Moriya interaction favors canted and chiral spin textures. , SOC further contributes to magnetic anisotropy, pinning preferred spin orientations, and couples spin behavior to lattice symmetry. , Precise control of ligand identity, connectivity, and orbital orientation, therefore, allows for tuning the balance among competing interactions at the atomic scale, transforming spin frameworks into chemically programmable lattices in which symmetry, exchange, and topology jointly define emergent magnetic and quantum phenomena.

The convergence of coordination chemistry, molecular design, and topological control enables bottom-up construction of spin–lattices with programmable quantum functionalities. Magnetic MOFs, radical-based COFs, and π-delocalized polymeric networks exemplify how chemical reticulation can propagate local spin coherence across macroscopic dimensions while retaining molecular tunability. ,,,− These platforms provide fertile ground for realizing designer spin–lattices, quantum spin liquids, and spin-based logic materials. Within this emerging field of reticular spintronics, chemistry acts as an architect by translating atomic-level spin building blocks into extended, coherent spin architectures capable of hosting collective quantum phenomena.

3. Precise Strategies for Spin Manipulation

The principles governing spin behavior in reticular materials provide a blueprint for intentional design and control. Spin is inseparable from its local coordination environment and the extended framework. The coordination geometry sets the electronic landscape and anisotropy, whereas lattice topology dictates long-range exchange pathways. These parameters are chemically tunable and responsive to external stimuli; therefore, perturbations can rebalance competing interactions, reorient spins, and stabilize new magnetic phases.

3.1. Internal Electronic and Coordination Framework

Spin properties in reticular materials originate from the microscopic electronic structure of their building units and the bonding pathways that mediate interactions. The coordination field lifts orbital degeneracies, and the competition between crystal-field splitting and electron-pairing energies determines the electronic configuration. For example, in the weak-field regime, CrCl₂(pyz)₂ (pyz = pyrazine) hosts Cr³⁺ in an elongated octahedral environment, yielding a high-spin d ³ (S = 3/2) configuration, , whereas exfoliated Cr­(pyz)₂ features tetracoordinated Cr²⁺ in a square-planar geometry, stabilizing a high-spin d ⁴ (S = 2) configuration (Figure a). , In the MOF-74 family, desolvation transforms octahedral sites into square-pyramidal centers, reshaping the crystal field landscape. Across the Mn²⁺ to Ni²⁺ series, this geometric modulation systematically tunes magnetic ordering from robust antiferromagnetism to ferromagnetic ground states, exemplifying how coordination geometry and electronic occupancy strictly dictate magnetic behavior in reticular solids. , More recently, extending such frameworks to heavier transition metals introduces additional electronic degrees of freedom, including enhanced orbital delocalization and SOC. For instance, a 4d coordination framework Mo­(pyz)₂I₂ exhibits ligand redox noninnocence and local symmetry breaking associated with radical linkers, leading to strong antiferromagnetic interactions and semiconducting transport behavior.

2.

Electronic and topological control of spin configurations in reticular frameworks. (a) Crystal-field regulation of spin states through ligand-field strength, electron-pairing energy, and geometric distortion, as exemplified by elongated octahedral CrCl₂(pyz)₂ and planar square Cr­(pyz)₂. ,,, (b) Magnetic orbital exchange governed by Goodenough-Kanamori-Anderson (GKA) rules, with strong 180° antiferromagnetic superexchange and weak 90° ferromagnetic interactions. (c) Radical-mediated exchange enabling spin communication between metal centers and organic radicals, with high-spin (HS) and low-spin (LS) Co nodes exhibiting different exchange couplings. (d) Distinct exchange pathways within triangular ligand motifs, with antiferromagnetic coupling in pristine triangulene frameworks ([TRI]) and ferromagnetic coupling in nitrogen-bridged analogues ([TRI­(N)]). (e) Competition between metal–ligand (J ₁) and ligand–ligand (J ₂) exchange interactions in Cr-based planar square motifs leading to ferrimagnetic ground states when J ₁ > J ₂ and altermagnetic states with J ₁ < J ₂. , (f) Electronic band structures in reticular materials, including conventional parabolic dispersions with a finite electron effective mass (m*), exotic linear Dirac bands with a zero m*, and flat bands with an infinite m*. (g) Geometric spin frustration induced by closed odd-cycle lattices in kagome-like Cu₃(HHTP)₂, enabling quantum spin liquid behavior. (h) Unconventional spin-splitting in zero-net-moment planar square motifs with opposite spins displaced from the highest 4-fold symmetry, as exemplified by the altermagnetic t-Cr₂(pyc-O₈) monolayer with tts topology.

Beyond defining local spin states, the coordination environment controls spin communication via metal–ligand orbital overlap. The Goodenough-Kanamori-Anderson (GKA) rules rationalize these superexchange pathways (Figure b). Linear or near-linear geometries typically favor σ-type overlap and strong antiferromagnetic coupling, whereas bent bridges and orthogonal orbital arrangements can stabilize ferromagnetic exchange. ,

The electronic nature of organic ligands fundamentally reshapes node-linker exchange. Transitioning linkers from passive bridges to active participants in coupling pathways. When ligand-based p orbitals resonate energetically with metal d states, enhanced d-p hybridization increases hopping amplitudes and can dominate over direct exchange. For example, in 2D Cr-pentalene frameworks, symmetry matching between Cr d _xy /d _xz orbitals and pentalene π orbitals generates robust ferrimagnetism with interaction strengths exceeding conventional superexchange pathways. Radical-bridged motifs provide complementary design principles. In radical-mediated Co-MOFs, ligand-centered spins hybridize with Co centers to dictate spin alignment, where high-spin Co enforces parallel radical alignment, whereas low-spin Co favors an antiparallel configuration (Figure c). This π–d–π coupling yields long-range order with intratrimer ferromagnetic and intertrimer antiferromagnetic configuration.

Strategic manipulation of frontier-orbital occupancy allows for the spatial redistribution of spin density, fundamentally altering the hierarchy of exchange interactions. Triangulene-based COFs illustrate how non-Kekulé topology and open-shell configuration can be chemically controlled (Figure d). The pristine framework exhibits antiferromagnetic coupling, whereas nitrogen substitution shifts frontier-orbital energies and redistributes π-spin density, driving a transition to ferromagnetic ground state. ,, Analogous physics arises in zigzag graphene nanoribbons, where edge-localized states form spin-polarized channels, ,,− and in Janus nanoribbons, symmetry breaking by controlled defects preserves a single ferromagnetic edge. In Cr­(pyz)₂-based MOFs, replacing nitrogen with heavier pnictogens lowers ligand lone-pair orbitals, enhances d–p hybridization, and significantly raises Curie temperatures through strengthened exchange. In contrast, a framework built from linkers with nonbonding molecular orbitals (NBMOs) redistributes spin density away from coordinating N atoms to α-carbons, suppressing metal–ligand coupling while fostering stronger and prompting ligand–ligand p–p interactions. This NBMO-driven relocation inverts the typical hierarchy of exchange pathways and stabilizes the altermagnetic ground state (Figure e). Furthermore, modulating the spatial delocalization of ligand's lowest unoccupied molecular orbital can reconfigure and reinforce spin-exchange pathways, leading to nearly an order-of-magnitude increase in ordering temperature. By rationally tuning linker electronics and maximizing node-linker overlap, reticular architectures can be designed to support high-temperature or even room-temperature magnetic ordering. ,,,,,−

In reticular materials, topology operates simultaneously at both structural and electronic levels. The geometric net not only arranges nodes in space but also fixes the coordination environment and Wyckoff multiplicities in the lattice, thereby prescribing the form of the electronic Hamiltonian (Figure f). For example, honeycomb nets naturally generate Dirac-like dispersions, while Lieb lattices can support flat bands arising from quantum interference. Kagome frameworks uniquely combine these attributes within the same electronic manifold. −

Topology also determines which magnetic configurations are accessible. Bipartite nets can accommodate two-sublattice antiferromagnetism, whereas lattices with closed odd cycles will introduce geometric frustration. This frustration fundamentally reshapes the magnetic ground state. , In the kagome framework, such as Fe₃(C₆O₆)₂, triangularly arranged Fe²⁺ (S = 2) centers cannot simultaneously satisfy nearest-neighbor antiferromagnetic coupling, leading to a manifold of nearly degenerate noncollinear configurations. Similarly, in Cu₃(HHTP)₂ (HHTP = hexahydroxytriphenylene), frustration in an ideal kagome network suppresses static long-range order and stabilizes spin-liquid-like regime behavior (Figure g). Furthermore, 3D topologies with tunable pore architectures offer additional control over magnetic anisotropy, correlation strength, and long-range coherence. −

Beyond frustration, specific lattice symmetries can generate unconventional spin organizations such as altermagnetism. In planar square-derived tessellations, occupation of Wyckoff sites with multiplicity greater than one enforces rotational symmetry relations between opposite spin sublattices. This arrangement breaks time-reversal (T) symmetry while preserving zero net magnetization, yielding momentum-dependent spin splitting even without SOC (Figure h). This principle evolves from Lieb lattices to more complex tessellations, in which symmetry-programmed spin splitting becomes pronounced. For example, tetragonal Ca­(pyz)₂ MOF with antiparallel spins at mm2-symmetric sites displays Lieb-type altermagnetic behavior, and π-conjugated frameworks such as t-Cr₂(pyc-O₈) (pyc = pyracylene) exploit tts topology to stabilize altermagnetic state through long-range d–π–π–d exchange. Lattice and spin symmetry constraints have also been verified to realize g-wave altermagnetism in 3D MOFs with D _2d symmetry, as exemplified by Co­(pymo)₂ and its halogen-substituted derivatives.

3.2. External Regulation

The intrinsic electronic structure and exchange pathways of reticular spin architectures can be complemented by their responsiveness to external perturbations. Since the spin landscape in these materials is strongly coupled to bonding geometry, frontier orbital alignment, and lattice coherence, modest stimuli can reorganize spin populations, reshape anisotropy, and reconfigure collective magnetic states. Rather than serving as isolated perturbations, such stimuli offer intuitive handles for the dynamic and reversible tuning of spin functionalities.

3.2.1. Chemical and Electronic Modulation

Chemical and electronic modulation adjust spin behavior by reshaping the underlying electronic environment that dictates magnetic moments and their interactions. Changes in electron count, orbital population, or ligand field strength adjust spin density and the energetic hierarchy of spin states. Doping provides a versatile strategy for such modulation. Elemental doping introduces foreign species into lattices via ion exchange, guest insertion, or redox-mediated binding, modifying local ligand fields while preserving the long-range periodicity. In Ni-MOF-74, controlled Fe doping replaces Ni sites and reorganizes the magnetic couplings along metal-oxo chains (Figure a). Low Fe content generates Ni–O–Fe linkages that strengthen intrachain antiferromagnetic coupling, whereas higher doping concentrations produce Fe–O–Fe segments and ferrimagnetic ordering with spontaneous magnetization without compromising crystallinity. Similar behavior has been reported in chemically doped COFs, where energy-matched dopants localize charge carriers through supramolecular charge-transfer interactions, thereby stabilizing spin-polarized states and enabling metal-free magnetism.

3.

External regulation of spin states in reticular materials. (a) Elemental substitution tunes local magnetic exchange pathways, as illustrated by Fe incorporation into Ni-MOF-74. (b) Carrier doping shifts the Fermi level (E _F) through electron (e ^–) or hole (h ⁺) injection, redistributing spin populations across frontier bands. (c) Strain alters metal–ligand distances and crystal-field splitting, modifying orbital overlap and spin states. (d) Electric gating ( E ) induces layer-dependent band shifts via valley-layer coupling, enabling unipolar or bipolar magnetic semiconducting behavior. , (e) Light-induced excited spin-state trapping between low-spin (LS) and high-spin (HS) manifolds of Fe­(II) sites in Fe₂[Nb­(CN)₈]·(4-pyridinealdoxime)₈·2H₂O.

Carrier doping regulates magnetism by manipulating band filling, a strategy that is particularly effective in reticular magnets with narrow or hybridized bands. In these systems, modest shifts in electron population can reorganize exchange pathways and induce spin polarization which is absent in the pristine lattice. For example, in the TPPy-BCNB (TPPy = 1,3,6,8-tetrakis­(2-phenyl)­pyrene, BCNB = 1,4-bis­(2-crylonitrile)­benzene) COF with Lieb-type topology, introducing 0.5 holes per unit cell disrupts sublattice balance, lifting flat-band degeneracy to generate spontaneous ferromagnetism. Theoretical calculations further indicate that increasing the hole concentration drives a crossover from ferromagnetic to antiferromagnetic ground states.

In spin-polarized systems, doping primarily shifts the Fermi level (E _F) to modulate the transport. With an unchanged magnetic ground state, electron doping generally raises E _F, whereas hole doping lowers it, corresponding respectively to downward or upward shifts of the electronic bands (Figure b). In bipolar magnetic semiconductors (BMSs), the valence band maximum and conduction band minimum exhibit opposite spin polarizations. By tuning carrier density, E _F can be shifted into a specific spin manifold, enabling a reversible transition from a BMS to a half-metal with a fully spin-polarized channel. ,,,

Chemical tautomerization provides an alternative route to switchable magnetism. Processes such as lactim-lactam interconversion involve proton transfer that reorganizes π-electron distribution, toggling linkers between closed-shell (S = 0, lactim) and radical (S = 1/2, lactam) forms and thereby driving dynamic magnetic transitions carrying an effective spin, thereby effectively driving dynamic magnetic state transitions (Figure b). , Related proton-coupled processes also modulate transport and ionic conduction in MOF-based core–shell systems.

3.2.2. Physical Stimuli

Reticular materials respond sensitively to external physical fields, leveraging their coherent lattices to propagate the influence. Since magnetic ordering relies on a delicate balance among crystal-field environments, frontier orbital alignment, and lattice geometry, external perturbations act as powerful levers to modulate these parameters (Table ). These responses are often linked to SCO phenomena, where modest stimuli shift the energetic competition between spin states, reorganizing local fields, and altering long-range exchange.

1. Physical-Field-Driven Spin Tunability in Reticular Materials.

field type	primary mechanism	advantages unique to reticular materials	typical examples
mechanical	framework deformation, bond angle and length distortion, crystal-field and orbital overlap modulation, spin–lattice coupling	structural softness, flexibility and deformability, topological geometry, guest-amplified mechanical effects	breathing pores, low-dimensional frameworks, − , perovskite-like frameworks −
electric	electrostatic gating, charge redistribution, field-driven polarization, orbital occupancy tuning	designable charge transport pathways, field-responsive polar environments, thin-film processability	ABX3-type multiferroic MOFs, − layered 2D MOFs and COFs −
optical	light-induced excited spin-state trapping (LIESST), guest-driven light-induced spin change (GD-LISC), photoinduced charge transfer, radical generation	rigid host lattices enabling cooperative photomagnetism, uniform coordination environments for efficient and site-selective photoexcitation	spin-crossover Hofmann-type MOFs −
magnetic	Zeeman splitting, spin ordering, metamagnetism	tunable exchange pathways, heteroatom engineering, geometry-defined magnetic anisotropy	mixed-metal magnetic MOFs
thermal	magnetic transition temperature, spin-phonon coupling, thermal expansion, entropy-driven spin crossover	large thermal hysteresis, cooperative lattice response, spin-state-dependent coordination bond flexibility	Fe(II)-based spin-crossover frameworks ,

Mechanical forces regulate magnetic behavior through two primary modes. Strain can induce directional distortion by modifying specific bond lengths and angles to tune crystal-field splitting (Figure c), whereas pressure imposes more isotropic compression. In the breathing framework MIL-47­(Mn), structural changes between large- and narrow-pore forms alter intrachain couplings and switch the magnetic ground state from antiferromagnetic to ferromagnetic. In low-dimensional frameworks, uniaxial and biaxial strain modulate orbital hybridization, generating control over spin states, , band gaps, and topological quantum phases. In hybrid perovskite-like MOFs, pressure enhances Jahn–Teller distortions to tune multiferroicity. − In 2D triarylmethyl-based COFs, compression drives a transition from an antiferromagnetic Mott insulator to a semimetal. SCO systems often exhibit cooperative mechanical responses, with thermal expansion or contraction modulating metal–ligand distance, pore size, crystal-field splitting, and thereby changing the equilibrium between low-spin and high-spin states.

Electric fields regulate magnetism in reticular materials by redistributing charge and modifying orbital occupations. Electrostatic gating shifts E _F, while field-induced polarization alters the local electrostatic environment at nodes and linkers. Owing to their designable charge-transport channels, polar domains, and accessible redox states, reticular materials exhibit particularly robust magnetic responses to electric stimuli. ABX₃-type multiferroic MOFs exemplify this coupling (Figure d). In these frameworks, electric fields act on dipolar A-site cations and distort the BX₃ framework, with geometric changes feeding back into the magnetic lattice and enabling electric-field control of magnetization. − In layered van der Waals architectures, valley-layer coupling further enriches the response. In A-type antiferromagnetic bilayers, a perpendicular field generates different electrostatic potentials on adjacent layers, shifting their spin-resolved band edges and converting a symmetric antiferromagnetic semiconductor into unipolar or bipolar magnetic semiconductors. In bilayer altermagnetic MOFs, the S ₄-symmetry protects spin-valley-layer coupling. Out-of-plane electric fields enhance momentum-dependent spin splitting at one valley while suppressing it at its symmetry partner, enabling polarity-switchable spin-valley textures. Furthermore, electric fields can trigger the controlled lifting and restoration of symmetry-protected band crossings, enabling precise, reversible transitions between distinct topological quantum phases.

Light provides another powerful stimulus by promoting electronic excitations that perturb the spin manifold, modify crystal-field environments, and activate local geometric relaxations. In SCO systems, photoexcitation directly promotes electrons from low-spin to high-spin states, expanding metal–ligand bonds, and reorganizing spin populations. This mechanism underpins the light-induced excited spin-state trapping (LIESST) systems, where metastable high-spin states generate pronounced magnetic changes in rigid frameworks (Figure e). Beyond the direct coordination sphere excitation, photoactive guests offer an additional route. In Hofmann-type Fe­(II) MOFs loaded with azobenzene, reversible trans–cis isomerization produces a guest-driven light-induced spin change (GD-LISC). This process modulates the host–guest interactions and local ligand field, enabling large, fully reversible magnetic responses over broad temperature ranges. Photoinduced changes can simultaneously couple to other physical degrees of freedom. In Fe–Pt cyanide frameworks hosting anthracene, light-induced deformation of FeN₆ octahedra, coupled with correlated guest displacements, reorganizes local electric dipoles, achieving concerted magnetic and dielectric switching. Furthermore, in frameworks where asymmetric host–guest interactions stabilize intermediate spin states, wavelength-selective irradiation can access hidden high-spin and low-spin configurations, producing optically addressable tristability thermally inaccessible.

Magnetic and thermal fields provide an additional control. Magnetic fields adjust spin configurations via Zeeman coupling and induce spin reorientation or metamagnetic transitions in mixed-metal frameworks. Simultaneously, thermal fluctuations can induce lattice expansion and modify crystal-field splitting, shifting the balance between ordered and crossover spin states. , These stimuli can act cooperatively, with one sensitizing the lattice to another, thereby offering multimodal pathways to complex spin states. In concert, chemically and physically driven perturbations underscore the reconfigurability of reticular materials and their potential as platforms for dynamically tunable spin architectures.

4. Spin Functionalities in Reticular Materials

4.1. Spin-Based Charge Transport

Spin polarization and filtering emerge when the electronic structure distinguishes between spin-up and spin-down carriers. In tunneling junctions (Figure a), two ferromagnetic electrodes are separated by an insulating barrier, and electrons tunnel with probabilities determined by the matching of the spin-polarized density of states. Parallel configuration of electrode magnetizations yields efficient tunneling from one majority-spin state to another, resulting in low resistance. Conversely, in the antiparallel configuration, the mismatch of majority-to-minority state suppresses tunneling and produces high resistance, giving rise to TMR and GMR. , Building on this mechanism, organic spin valves integrating reticular barriers have been realized, with reticular thin films acting as spin-transport layers between ferromagnetic contacts (Figure b). − The prevalence of light elements with weak SOC in MOFs and COFs prolongs spin relaxation, making these frameworks promising for preserving spin coherence over long distances.

4.

Spin functionalities in reticular materials. (a) Electron tunneling in magnetic junctions composed of two ferromagnetic electrodes (F1 and F2) separated by an insulating barrier (I). (b) Diagram of a vertical organic spin valve and magnetoresistance (MR) loop. − The MR ratio is defined as (R _AP – R _P)/R _P × 100%, where R _AP and R _P represent the overall device resistance of the antiparallel and parallel magnetization conformation, respectively. (c) Bipolar magnetic semiconductor (BMS)-based field-effect spin filter. A gate voltage ( V ) applied on BMS tunes the position of E _F and selectively populates either spin-up or spin-down carriers, enabling controllable generation of oppositely polarized output currents ( I ). (d) Quantum anomalous Hall effect in topological magnetic lattices with intrinsic magnetic moments ( M ), as exemplified in the kagome ferromagnetic Mn₃(C₆O₆)₂, which hosts a topological band gap with nonzero Berry curvature (C = 1) and spin-polarized chiral edge states without an external magnetic field. Reproduced with permission from ref . Copyright 2023 American Physical Society. (e) Spin Hall effect in d-wave altermagnets, as exemplified in Ca­(pyz)₂ monolayer with orthogonal spin current ( I _s ) and charge current ( I _c ) under an in-plane electric field ( E ). (f) Chirality-induced spin selectivity (CISS) in helical reticular structures. Electron transport through left- and right-handed chiral channels yields opposite spin polarizations, enabling enantioselective spin filtering. (g) Magnetoelectric coupling in multiferroic reticular frameworks, as exemplified by perovskite-like AB­(HCOO)₃ (A = cations, B = metals). Cooperative Jahn–Teller distortions drive a symmetry lowering from a nonpolar (mmm) to a polar (mm2) phase, coupling structural, electric and magnetic order parameters. ,,

BMSs enable gate-tunable spin filtering within a single-material channel (Figure c). In a BMS, valence and conduction band edges are fully spin-polarized but possess opposite spin characters. Consequently, shifting E _F across the band gap selects either spin-up or spin-down states as the majority transport channels. An applied gate voltage can thus switch the sign of spin polarization without altering the underlying magnetic order, providing a purely electrical control of spin injection. The synthetic flexibility of reticular chemistry, combined with the BMS concept, offers a versatile route to reconfigurable spin filters and transistors that operate at low powers. ,,,,,

4.2. Emergent Hall Effects

Hall effects encompass a class of transverse transport phenomena where carriers are deflected perpendicular to the applied field. In ferromagnets, broken T symmetry produces electronic bands with finite Berry curvature, generating the anomalous Hall effect (AHE). , When magnetic order yields topologically nontrivial bands with nonzero Chern numbers, the quantum anomalous Hall effect (QAHE) emerges, characterized by quantized conductance without external fields. Since Chern bands naturally arise in Dirac or flat-band lattices, QAHE can be engineered in honeycomb or kagome frameworks whose reticular architectures support these specific topologies (Figure d). ,,−

Distinct from QAHE, the spin Hall effect (SHE) generates a transverse pure spin current without net magnetization. SHE is particularly robust in altermagnetic frameworks, where spin-split bands arise from specific spin and crystalline symmetries without SOC. ,, In Ca­(pyz)₂-type frameworks, alternating spin sublattices are encoded directly into the framework topology, and the {C ₂||C ₄} spin symmetry (Figure d) enforces alternating spin arrangements with 90° periodicity in momentum space, creating pronounced anisotropic transport (Figure e). When an in-plane electric field aligns with specific spin lobes, longitudinal spin-polarized currents dominate, whereas alignment with nodal directions yields a transverse spin current, realizing a symmetry-driven SHE in light-element lattices with negligible SOC.

4.3. Chirality and Chiral-Induced Spin Selectivity

Reticular chemistry enables direct encoding of molecular chirality into extended lattices, where rigid linkages preserve asymmetric electrostatic fields over long distances. ,− This structural asymmetry underlies the chiral-induced spin selectivity (CISS) effect, in which electron motion through helical or chiral potentials becomes intrinsically coupled to spin (Figure f). As carriers traverse these pathways, interactions between their momentum and the chiral electric field generate emergent SOC, lift spin degeneracy, and produce highly spin-dependent transmission. In Dy­(III)-l-tartrate MOF, multidimensional helicity combined with strong SOC from Dy­(III) yields near-ideal spin filtering. Similarly, Fe-Spiro MOF demonstrates how reticular confinement can induce single-handed helicity in polymerized guest chains, amplifying the chiral potential to drive spin polarization up to 94%. In COFs, robust CISS arises when chirality is embedded into the extended π-lattice through spontaneous resolution, axial-chiral building blocks, helical organization, or programmed lattice torsion. ,, Incorporating chiral conduction pathways within reticular pores further enhances spin-selective transport.

Chirality also functions as a symmetry-breaking element. In noncentrosymmetric frameworks, the interplay between chirality and SOC induces Rashba-Dresselhaus splitting, enabling electric-field control of spin textures. In chiral magnetic frameworks, broken P symmetry stabilizes noncoplanar spin configurations and finites scalar spin chirality, generating emergent magnetic flux and manifesting quantum anomalous and quantum topological Hall effects. Chirality can even be imprinted and preserved during framework reconstruction, as demonstrated in cage-to-COF transformations where an initial chiral bias survives despite using achiral precursors.

4.4. Multiferroics and Magnetoelectric Coupling

Multiferroics simultaneously host two or more ferroic orders, typically ferroelectricity, ferromagnetism, and ferroelasticity. From a symmetry perspective, ferroelectricity requires broken P-symmetry to support spontaneous polarization, ferromagnetism requires broken T-symmetry to stabilize long-range spin order, and ferroelasticity emerges from symmetry-lowering structural transitions that generate switchable strain variants.

A central feature of multiferroics is magnetoelectric coupling, where electric and magnetic order parameters are inextricably linked. Classical ABX₃-type MOFs illustrate how such coupling can be engineered (Figure g). In these frameworks, A-site cations and X-site anions can break P symmetry to generate ferroelectricity, while B-site transition metals furnish unpaired d orbitals, driving magnetism. − ,− Spin-dependent lattice distortions, orbital orderings, and exchange mechanisms link ferroelectric and magnetic sublattices, enabling partial control of magnetization by electric fields and vice versa.

2D reticular framework broadens multiferroic design by exploiting chemically tunable local asymmetries. Atomic displacements, linker rotations, and asymmetric bonding can robustly break P symmetry and generate ferroelectricity. ,− For example, in NbPc (Pc = phthalocyanine), the off-center displacement of metal ions induces in-plane polarization concurrent with magnetic order. Similarly, in Cr­(h-fpyz)₂, half-fluorination of pyrazine linkers introduces strong dipoles without disturbing magnetic superexchange pathways, stabilizing room-temperature multiferroicity. Sliding ferroelectricity provides a complementary mechanism in layered frameworks. The intrinsic flexibility of reticular lattices allows controlled lateral shifts between layers, and even subangstrom sliding can effectively remove P symmetry and generate switchable out-of-plane polarization in magnetic architectures.

5. Summary and Outlook

Reticular spintronics introduces a transformative frontier in both physical and chemical sciences, establishing a seamless continuum between bottom-up atomic- and molecular-level chemical design and top-down spin functionality. By unifying the modular precision of coordination chemistry with the fundamental principles of quantum magnetism, this emerging field treats atomic and molecular spin-active units not merely as static placeholders but as dynamically programmable building blocks within periodic architectures. Through the rational encoding of lattice symmetry and connectivity, local magnetic moments can be orchestrated into engineered collective behaviors, ranging from robust long-range order to exotic quantum spin states. This framework provides a universal chemical language that translates orbital-level modifications directly into the complex spin-transport and logic functionalities required for next-generation spintronic technologies.

Looking forward, the theoretical landscape of spintronics, which was historically sculpted around the physics of rigid inorganic solids, finds a vast and largely unexplored playground within reticular systems. MOFs and π-conjugated frameworks offer unparalleled chemical tunability, enabling the experimental realization of canonical quantum models under highly tailorable conditions. The relationship between reticular chemistry and condensed matter physics is inherently symbiotic. While spin theories are well-understood in discrete atoms and molecules, their universal role in extended frameworks remains a critical frontier. Consequently, rigorous theoretical modeling moves beyond a descriptive role to become an indispensable architectural tool, allowing researchers to anticipate, simulate, and program the collective behavior of spin networks prior to experimental manifestation.

Beyond magnetic order, reticular spintronics naturally extends into quantum information science, where localized spins serve as fundamental units of qubits. High-fidelity quantum operations demand a rigorous balance between spin isolation to minimize decoherence and controlled exchange to mediate the entanglement. Reticular chemistry addresses this trade-off by enabling the periodic, atomically precise placement of spin centers within a symmetry-programmable environment. , The local spin Hamiltonian can be tuned to suppress relaxation pathways, while the linker electronics define the strength and range of interqubit exchange. Furthermore, exploiting higher-spin states allows for the generation of multiquantum-bit gates within the framework.

However, simple “sum-of-the-parts” intuition often fails, as assembly of molecular units into extended lattices often triggers unexpected redistributions of spin densities, symmetries, and exchange pathways. Capturing these complexities demands a unified evolution of theory and computation, adapting advanced tools from solid-state physics, such as effective Hamiltonians, many-body perturbation techniques, and quantum embedding methods, to hybrid molecular systems. A unified theoretical foundation is therefore essential to identify transferable descriptors and symmetry rules that capture the electronic rearrangements inherent to framework construction. Building upon these formalisms, the integration of high-fidelity magnetic framework databases and advanced electronic structure prediction models, exemplified by DeepH and HamGNN, enables a mechanism-data dual-driven research paradigm. These principles can be encoded into physics-informed machine learning models and computational workflows capable of exploring vast chemical design spaces. − When coupled with accessible software platforms, such workflows facilitate high-throughput screening and AI-enabled generative inverse design, − directly linking targeted spin functionalities to experimentally realizable structures.

Bridging this computational pipeline with an experimental realization remains a formidable challenge. The synthesis of highly crystalline, defect-controlled reticular materials is no longer just a chemical milestone but also a fundamental prerequisite for reliable device integration. In a device environment, the inherent structural softness of molecular lattices creates a potential mismatch with rigid inorganic electrodes, which can lead to interfacial spin scattering that overwhelms predicted spin polarization. Addressing this necessitates a move beyond simple structural matching toward the engineering of electronic hybrid states at the contact surface to ensure an efficient spin injection. Furthermore, the modularity of these frameworks makes them uniquely amenable to closed-loop robotic synthesis and automated discovery platforms, allowing for the precise, high-speed exploration of complex chemical space.

Ultimately, as theoretical insight, algorithmic development, and experimental capability converge, reticular spintronics is poised to mature into a precision-driven platform for encoding and exploiting spin in designed quantum matter. This approach facilitates a fundamental transition from serendipitous discovery to a predictive framework, where target functionalities reverse engineer the requisite lattice topologies, coordination environments, and building block chemistries. By moving beyond case-by-case demonstrations, the field heralds a transformative inverse design frontier, where chemists, physicists, and materials scientists converge to translate desired functional behaviors into precisely engineered architectures.

Y.C. conceived and prepared the project under the supervision of H.L. and X.W. All authors discussed the context and contributed to editing the manuscript.

The authors declare no competing financial interest.