Table 1.

Description, types, advantages, and limitations of common synthesis methods for cyclodextrin-based metal–organic frameworks

Synthesis method	Description	Type of CD-MOFs	Advantages	Limitations	References
Vapor diffusion	The vapor diffusion method is one of the earliest techniques for the synthesis of cyclodextrin-based metal–organic frameworks The conditions used in this diffusion method are mild, requiring only 2–7 days at room temperature (∼25 °C) and pressure	γ-CD-MOF-1 K2(C48H80O40)(OH)2 Mixed metal Li/K-γ-CD-MOF γ-CD-MOF-2 Rb2(C48H80O40)(OH)2 γ-CD-MOF-3 Cs2(C48H80O40)(OH)2 γ-CD-MOF-4 (C24H40O20)(CsOH) (CH3OH) Na-α-CD-MOF ([Na(H2O)(C36H60O30)]·H2O) α-CD-MOF (K3(C36H60O30)2·7H2O)	The simplicity of the synthesis does not need heating Sensitive cyclodextrin-based metal–organic frameworks under mild reaction conditions are synthesized The quality of crystals obtained in this system can be evaluated directly by X-ray diffraction An important application of this method is to concentrate very low volumes of solutions of proteins Vapor diffusion may be useful for the crystallization of proteins that cannot be obtained at high concentrations and may also find applications for concentrating solutions of other samples available in small quantities	High reaction time The vapor diffusion method is difficult to be used to manufacture CD-MOF for large-scale production and future industrial use	(He et al. 2019a; Forgan et al. 2012; Abuçafy et al. 2018)
Microwave-assisted	Microwave-assisted synthesis works based on aligning dipoles of the material in an external field via the excitation produced by microwave electromagnetic radiations and is usually executed in combination with a known synthesis strategy Microwave-assisted synthesis is a potential route to accelerate the synthetic process because of the rapid and selective heating characteristics of microwave-assisted synthesis	CD-MOF-1 γ-CD-MOF-1 K2(C48H80O40)(OH)2	Microwave-assisted heating can deliver energy instantaneously to targeted components through the interaction of the alternating electromagnetic field with reactants The microwave-assisted technique can lead to a dramatic reduction in synthetic time of metal–organic frameworks from days to minutes Possibility of controlling crystal size Higher yield in remarkable phase purity and phase selectivity Compact synthetic device usage. Synthetic devices with low energy consumption while producing small amounts of chemical waste	The possibility of changing the reaction conditions by regulating the irradiation power is difficult Diverse instruments cannot deliver the same conditions, ultimately hindering reproducibility; therefore, the time of reaction and temperature are also limitations This method requires high-temperature heating, which may limit the popularization of microwave-assisted synthesis	(Sharanyakanth and Radhakrishnan 2020; Liu et al. 2017a; Zhao et al. 2022a)
Hydro/Solvothermal	Hydro/solvothermal synthesis is one of the most typical and effective synthetic methods for constructing nanomaterials with various morphologies, such as cyclodextrin-based metal–organic frameworks This method is carried out using pressure-resistant sealed vessels such as autoclaves or reactors at high ambient pressure greater than 1 atm and temperature greater than 100 °C in the existence of liquids such as water or organic solvent The method is called either a hydrothermal or a solvothermal technique based on the liquid used in the method The method is known as hydrothermal when water is utilized as a reaction medium The method is solvothermal when the nonaqueous solvents are used as a reaction medium	CD-MOF-1 γ-CD-MOF-1 K2(C48H80O40)(OH)2 β-CD-MOF ((C42O35H70)2(NaOH)4·H2O) β-CD-MOF (CD-MOF-1), Cs(OH)·(C42H70O35) β-CD-MOF (CD-MOF-2), [Cs1.5(C42H66.5O35)]2 α-CD-MOF ((C36H60O30)·H2O)	These synthetic methods offer the advantages of simple, rapid, inexpensive, environment-friendly, and efficient nonconventional heating with high yields Single crystals are readily obtained Single-crystal X-Ray Diffraction is used for structural characterization	Soluble precursors are required Heat and/or aggressive reagents (acids, organic solvents, bases) are needed for regent dissolution Solvent waste generation is high Potentially hazardous handling of explosive/corrosive metal salt, e.g., nitrate/chloride in the presence of organic liquids Waste mineral acids or salts are generated by reactions, e.g., nitric acid and hydrochloric acid Not applicable to heat-sensitive solvents and reagents	(Sharanyakanth and Radhakrishnan 2020; Han et al. 2018; Ding et al. 2019; Kang et al. 2021)
Ultrasound-assisted method	Ultrasound has become an important tool due to the ultrasound applications in the synthesis and modification of nanosized functional inorganic materials Ultrasonic irradiation was introduced for the synthesis of materials with unusual properties Cavitation bubbles grow closer to the solid surface and collapse at a higher amplitude forcing metal ions to bind with cyclodextrin, further accelerating the construction of the cyclodextrin-based metal–organic frameworks system within a short time	α-CD-MOF/Teflon γ-CD-MOF/Teflon β-CD-MOF/Teflon	Fast, environmentally friendly, energy-efficient, room temperature method, nanocrystalline particles synthesis Ultrasonic waves generate vibrations that can create voids that transfer energy to solid particles immersed in the liquid Cavitation generated by ultrasound eases the binding of cyclodextrin molecules with metal ions; thereby, the preparation of cyclodextrin-based metal–organic frameworks can be carried out under mild processing conditions In ultrasound, green solvents can be used to replace toxic organic solvents Cyclodextrin-based metal–organic frameworks obtained by ultrasonic irradiation are thermally more stable than other methods	Sometimes the synthesis temperature near the reactive mixture area cannot be controlled even through a room temperature synthesis method	(Hajra et al. 2021; Shen et al. 2022)

Synthesis methods of CD-MOFs are briefly described. Types of cyclodextrin-based metal–organic frameworks are briefly summarized. The advantages and limitations of cyclodextrin-based metal–organic frameworks synthesis methods are briefly described. CD-MOFs refer to cyclodextrin-based metal–organic frameworks