Skip to main content
NCBI home page
ACS AuthorChoice logoLink to ACS AuthorChoice
. 2025 Aug 6;147(33):30317–30325. doi: 10.1021/jacs.5c09618

Catalytic Nitrous Oxide Degradation with Group 15 Clusters

Bono van IJzendoorn †, Reece Lister-Roberts †,‡, Nikolas Kaltsoyannis ‡,*, Meera Mehta †,*
PMCID: PMC12371874  PMID: 40767358

Abstract

Nitrous oxide (N2O) is sometimes referred to as the forgotten greenhouse gas, but ignoring it would be a mistake. N2O has a greenhouse warming potential 300× that of CO2, and anthropogenic emissions are increasing. Yet, compared to CO2, homogeneous catalysts that mediate its reduction are scarce. We present a range of cluster catalysts based on abundant and inexpensive p-block elements that mediate the conversion of N2O to environmentally benign N2. The catalysts studied offer many critical advantages, and systems can be tuned for performance, recyclability, selectivity, air stability, and commercial availability. Pnictogen clusters present themselves as a general platform in N2O reduction chemistry, and control reactions confirm that these clusters offer access to reactivity that simple monopnictogen molecules do not. Mechanistic investigations reveal that the low-valent clusters can access a –1/+1 redox couple, which goes beyond classical main group redox couples and will unlock a vault of hitherto unknown chemical space.

graphic file with name ja5c09618_0008.jpg

graphic file with name ja5c09618_0006.jpg

Introduction

The presence of nitrous oxide (N2O) in the atmosphere is no laughing matter. N2O is a leading contributor to ozone depletion, with an estimated greenhouse warming potential 300× greater than CO2 and a lifetime of ∼114 years. Anthropogenic emission of N2O has been increasing by approximately 0.2% per annum, and one remediation strategy is to convert N2O into N2. Chemically, transfer of O and generation of N2 is thermodynamically favorable; nature does this in microbial denitrification processes. However, due to its high kinetic inertness, only a handful of synthetic homogeneous catalysts, primarily reliant on transition metals, − have been found to mediate N2O degradation (Figure a).

1.

1

Open in a new tab

(a) Homogeneous catalysts based on these elements mediate N2O reduction. (b) Molecular structures of reported p-block catalysts that deoxygenate N2O. (c) General structures of the cluster catalysts studied in this work.

There has been global interest in developing organo-main-group catalysts as sustainable alternatives to transition metal systems. And although numerous p-block compounds, including frustrated Lewis pairs (FLPs) and carbenes, − have been reported to capture and cleave the N–O bond of N2O stoichiometrically, catalytic degradation remains a significant challenge. One early example of transition metal-free homogeneous N2O reduction was reported by Cantat and coworkers in 2019, with fluoride anion as a (pre)­catalyst. Then, Cornella reported a Bi­(I) species that mediates N2O deoxygenation via a 2e– Bi (I)/Bi­(III) redox cycle (Figure b). And, in 2024, Mo et al. reported an Sn complex that mediates this reduction through cooperativity with neighboring Ge atoms. These precedents demonstrate that low oxidation state main group compounds interact with N2O to be oxidized and release N2, but in order to achieve catalytic turnover, the generated oxidized product must be susceptible to reduction. This reduction is a key limitation in explaining why lighter main group systems have previously eluded N2O reduction catalysis. For example, phosphines react with N2O to give phosphine oxides, where the phosphorus +5 oxidation state is highly stable. ,

Although a new field, there is growing interest in employing main group clusters in catalysis, in part because clusters can be understood as intermediaries between discrete molecules and difficult-to-study bulk solidsallowing them to act as soluble, atom-precise molecular prototypes. Compared to homogeneous systems, heterogeneous catalysts are often preferred for high-volume industrial processes, given their greater propensity for recycling and easy separation, which minimizes downstream purification costs. Heterogeneous pnictogens like red phosphorus, violet phosphorus, and black arsenic are up-and-coming candidates for catalysis, but their poorly defined structures (which contain clusters), together with extreme insolubility, make understanding the reactivity of these materials difficult. Meanwhile, heptapnictogen clusters ([Pn7]; Pn = pnictogen, structure shown in Figure c) are easily synthesized and, owing to their solubility in common solvents, in situ monitoring of reactivity is relatively easy. It is also noteworthy that, in 2024, Su and Zhang found that black phosphorus alloyed with Li contained [P7] cages. And in the context of N2O chemistry, Mao et al. have detected N2O interactions with violet phosphorus in sensor materials. Further understanding is necessary to maximize the potential of pnictogen-based materials, both as catalysts and otherwise.

[Pn7]3– clusters present themselves as interesting candidates in N2O reduction chemistry as the bridging Pn atoms of the norticycle-type cage can be understood to have an oxidation state of −1 and a 2e– oxidation would convert them to +1; avoiding the +5 state. With a primary focus on the [Pn7] frameworks, herein, we interrogate a range of pnictogen clusters to mediate the hydroborative reduction of N2O. Mechanistic investigations show that [P7]3– can tap into a hitherto unknown −1/+1 redox couple. Other key findings are that the classic boron–phosphorus FLPs previously reported in N2O stoichiometric activation, and simple R3Pn molecules do not mediate N2O reduction, showing that these clusters enable chemistry that noncluster monopnictogen molecules cannot access. The arsenic systems were found to be the most catalytically active, and in recycling studies, catalytic competency was retained after nine cycles. Further, beyond the transfer of the N2O oxygen atom to boron, we establish that these oxygen atoms can be transferred to sulfur, constructing the first steps toward making sought-after element–oxygen bonds using N2O with transition metal-free catalysis. To demonstrate the reduction of other N–O bonds, nitro-functionalized organic compounds were converted to amines, which are high-value products in and of themselves for the pharmaceutical and agrochemical sectors. These are unprecedented transformations in transition metal-free cluster chemistry.

Results and Discussion

We have previously reported on a library of group 13 functionalized heptapnictogen clusters in the reduction of CO2 (isoelectronic with N2O), with the general molecular formula [M­(18c6)]2[(R2E)­Pn7] (18c6 = 18-crown-6; see Figure a for dianion structures): [Na­(18c6)]2[(BBN)­P7] ([Na­(18c6)]2[1]; BBN = 9-borabicyclo[3.3.1]­nonane); [Na­(18c6)]2[(iBu2Al)­P7] ([Na­(18c6)]2[2]); [Na­(18c6)]2[(Ph2In)­P7] ([Na­(18c6)]2[3]); and [K­(18c6)]2[(iBu2Al)­As7] ([K­(18c6)]2[4]). , Our initial studies focused on the reduction of N2O with this family of functionalized [Pn7] clusters, as well as the unfunctionalized [Pn7]3– clusters, [K­(18c6)]3[P7] ([K­(18c6)]3[5]) and [K­(18c6)]3[As7] ([K­(18c6)]3[6]) from which they are prepared. −

2.

2

Open in a new tab

(a) Homogeneous catalysts studied that are based on the [Pn7] framework. (b) Catalyst screening and control reactions. Full data tables are provided in the Supporting Information 2.5 and 2.6. NMR conv. was determined by 1H NMR spectroscopy using C6H6 as an internal standard. For [Na­(18c6)]2[1], [Na­(18c6)]2[2], and KPPh2 + 18c6, background DMF hydroboration was observed, and conversions were corrected to exclude this side reaction.

First, the reduction of 1 atm of N2O using [Na­(18c6)]2[1] at 3.33 mol % catalyst loading with different reductants and in different solvents was screened (Supporting Information 2.1 and 2.2). Pinacol borane (HBpin) as the reductant and dimethylformamide (DMF) as the solvent gave the best results, with >99% conversion to O­(Bpin)2 (7) and H2, observed by 1H and 11B nuclear magnetic resonance (NMR) spectroscopy. Observation of H2 and 7 is in line with the hydroborative catalytic degradation of N2O. ,− In these reactions, the internal nitrogen of N2O has been reduced to N2 (confirmed by 15N NMR studies, Supporting Information 2.3), and the hydride on the borane has been oxidized to H2, confirmed by D2 observed in the 2H NMR spectrum when DBpin was employed (Supporting Information 2.4).

Using the optimized conditions (DMF solvent, HBpin reducing agent, and 1 atm of N2O), the family of [M­(18c6)]2[(R2E)­Pn7] and the unfunctionalized [K­(18c6)]3[Pn7] (Pn = P, As) clusters (structures [1]2–[4]2 and [5]3–-[6]3– shown in Figure a) were surveyed at 1 mol % catalyst loading (Figure b). First, it was confirmed that, in the absence of a catalyst, no conversion is observed. Then, at 1 mol % [Na­(18c6)]2[1], a conversion of 82% to 7 after 1 h was obtained. Under the same reaction conditions, catalysts [Na­(18c6)]2[2] and [Na­(18c6)]2[3] gave more sluggish performances. While [K­(18c6)]2[4] was found to be the most efficient, with complete consumption of the borane observed after 1 h and a product distribution of 96% 7 and 3% HOBpin (8). Next, the unfunctionalized clusters were tested in a similar fashion, and for [K­(18c6)]3[5], an overall conversion of 85% was observed, while [K­(18c6)]3[6] gave complete conversion. These observations suggest that the catalytic competency is primarily directed by the cluster core rather than the exo-group 13 functionality, contrasting our previous studies of these clusters in CO2 reduction, where catalytic performance was more significantly influenced by the exo-functional group. We have previously found that, when testing Zintl phases in solution catalysis, the addition of a cation-sequestering agent increases performance, seemingly by increasing the clusters’ solubility. Thus, the phases K3Sb7 and K5Bi4 were also probed, but with excess 18c6 under identical reaction conditions, and although worse-performing did demonstrate catalytic turnover. Although the phosphorus systems show good catalytic performance, the arsenic clusters were found to be the most active.

A series of control reactions were performed to better understand the origin of catalytic turnover; Figure b shows selected controls, with others provided in the Supporting Information 2.6. Previously, the FLP combination B­(C6F5)3 and t Bu3P had been reported to stoichiometrically activate N2O, but when this FLP was trialed in catalytic quantities with HBpin, no catalytic turnover was achieved. Further, Ph3P and Ph3As were also tested, and again showed no catalytic activity, while KPPh2 gave low performance, with 15% of compound 7 generated after 1 h. These controls are of particular interest because they demonstrate that the [Pn7] cluster platform can access chemistry that classical FLPs and simple monopnictogen molecules cannot. The bridging atoms of the [Pn7]3– cluster can be considered pseudochalcogen-like and thus P4S3 was tested and, although low, showed some catalytic turnover, as did the (Me3Si)3P7 cluster.

The turnover frequency (TOF) of [K­(18c6)]3[6] (TOF max = 160 h–1) can be compared to other homogeneous catalysts reported in related N2O reductions (see Supporting Information 2.7.). These comparisons reveal that the performance of [K­(18c6)]3[6] is modest compared to Cornella’s Bi system (TOF max = 3120 h–1); however, it is noteworthy that the time of the Bi reactions was determined using a visual color change and not a spectroscopic method. While [K­(18c6)]3[6] outperforms Mo’s stannylone system (TOF max = 55 h–1) and Cantat’s method (TOF max = 10 h–1). , Compared to transition metal catalysts reported in the hydroborative reduction of N2O (TOF max between 36 and 100 h–1), , [K­(18c6)]3[6] remains competitive under similar or milder conditions. Meanwhile, hydrogenation of N2O mediated by homogeneous transition metal catalysts is often reported to be relatively slow (TOF max = 9–16 h–1), especially considering the higher pressures and/or temperatures required. Very recently, Trincado and Grützmacher reported a rhodium olefin-amine carbene complex that shows very high catalytic activity (TOF max > 1300 h–1) in the hydrogenation of N2O under moderate conditions (pH 2 1.5–3 atm, pN 2 O 1.5–3 atm, 65–80 °C, 10 eq. t BuOK).

Mechanistic Investigations

To probe the mechanism of N2O reduction, HBpin was investigated with [5]3– and [6]3– in a stoichiometric fashion, and NMR spectroscopy revealed decomposition after 1 h (Figure a; Supporting Information 3). These reaction mixtures were subsequently pressurized with N2O, and no production of 7 and/or 8 was detected. However, when stoichiometric reaction mixtures of [5]3– and [6]3– with HBpin were flash-frozen before being allowed to react and then pressurized with N2O, compound 8 could be observed by NMR spectroscopy. Addition of stoichiometric amounts of HBpin to these reaction mixtures revealed complete consumption of 8 and the formation of 7, consistent with dehydrocoupling between 8 and HBpin leading to 7. During the catalytic studies, reaction mixtures of [Pn7]3– and HBpin were immediately frozen prior to N2O addition, which led to high conversions of 7 and/or 8 being observed. However, if the [Pn7]3– clusters were first allowed to react with HBpin and then the reaction mixture was pressurized with N2O, only minor amounts of 7 were detected. These observations are consistent with the first catalytic step being the reaction of [Pn7]3– with N2O. When a DMF solution of [5]3– was allowed to react with 1 atm of N2O, gas evolution and an instant color change were observed. 31P NMR spectroscopy revealed three new resonances with an integration of 3:3:1 that are correlated, indicative of a tris-functionalized cluster with C3v symmetry. These resonances match literature reports for the [P7O3]3– cluster (Figure a I1’’’) where the bridging phosphorus atoms have been oxidized. Although single crystals suitable for X-ray diffraction (XRD) studies could not be obtained for I1’’’, structurally related N-substituted clusters were fully characterized, including with XRD studies by us in 2024, where computational investigations revealed that installation of the more electronegative N resulted in oxidation of the bridging P atoms, as would be the case with the oxygen-bound P atoms in compounds I1’–I1’’’. Efforts to obtain analytically pure I1’’’ salts were unsuccessful and prevented independent catalytic testing. However, cold stepwise addition of HBpin to in situ-generated I1’’’ allowed for the observation of regenerated [5]3–, along with [P5]− and [P16]2 – by NMR spectroscopy and high-resolution mass spectrometry (HRMS) (Figure a). The in situ-generated solution of these polyphosphides was repressurized with N2O, and the formation of I1’’’ could again be observed by NMR spectroscopy and HRMS techniques. These experiments demonstrate that a [5]3– ⇌ I1 catalytic cycle is possible, which can be understood as a P(−1)/P­(+1) redox couple at the bridging P atoms. Low-valent redox couples have been reported with the heavy pnictogen Bi, but not with its lighter congeners P and As.

3.

3

Open in a new tab

(a) Stepwise experimental studies into N2O reduction mechanism. (b) Postulated mechanism; see Supporting Information 10.2 for full details. (c) Hydroboration of N2O using Pn oxides. NMR conv. was determined by 1H NMR spectroscopy using C6H6 as an internal standard. Tabulated data are provided in Supporting Information 4.1. (d) Catalyst recycling studies for N2O hydroboration (catalyst loading = 1 mol %, except for As4O6 which was performed at 10 mol %). NMR conv. was determined by 1H NMR spectroscopy using C6H6 as an internal standard. Tabulated data are provided in Supporting Information 5.

To probe the catalytic cycle shown in Figure b further, we turned to density functional theory. Full details of the computational methodology, computational tables and figures, as well as the Cartesian coordinates and energies of all stationary points, are provided in the Supporting Information 10.2 and the source data file. In the following discussion, we focus on the reactions of [5]3–, and Figure S157 shows the computed mechanism for the cycle in Figure b. Cluster [5]3– reacts with N2O to form TS1, which then decomposes to form I1’ and release N2. An adduct is then formed between I1’ and HBpin. This rearranges via TS2 to form I2 and eliminates –OBpin. The protonated clusters [HPn7]2 – (I2) are known in the literature and can be deprotonated. The –OBpin then abstracts the H atom from I2 via TS3 to form HOBpin (8) and regenerates [5]3–. Energetic Span Model (ESM) analyses for both [5]3– and [6]3– indicate that the relative turnover frequency (TOF) of the latter is 68× that of the P analogue, in qualitative agreement with experimental results. As described in Supporting Information section 10.2, the ESM provides insights into the key intermediates and transition states that collectively determine the kinetics and TOF of the reaction. Table S12 indicates that, for both [5]3– and [6]3–, these key states are I2 and TS1 (Figure S157), respectively; these are the TOF-determining intermediate and the TOF-determining transition states. The energy difference between these two statesthe largest in the catalytic cycle, i.e., the energetic spandetermines the TOF. This energy difference is 3.8 kcal/mol smaller for [6]3– than [5]3–, and hence the As system exhibits the larger TOF.

We also studied the off-cycle reaction of I1’ with further N2O; the mechanism for this for [5]3– is shown in Figure S158. I1’ reacts with N2O via TS4 to form I1’’ and release N2. A similar process sees I1’’ react with N2O via TS5 to generate I1’’’. Comparison of the barrier heights for the reaction of I1’ with N2O versus that for the H transfer in the I1’-HBPin adduct suggests that the latter is the more likely route.

Interestingly, when a DMF solution of [6]3– was allowed to react with 1 atm of N2O a color change was observed, transitioning from dark red to colorless. While no single crystals suitable for XRD studies could be obtained when 18c6 was employed, switching to [2.2.2]­cryptand (crypt) allowed for the isolation of single crystals from the reaction mixture. XRD analysis of these crystals revealed the formation of [K­(crypt)]2[As4O7] ([K­(crypt)]2[9]) (anion shown in Figure a; 53% isolated yield). Anion [9]2– can be described as an oxidized arsenic trioxide molecule (As4O6 that has an adamantane cage-like structure), where one of the bridging As–O bonds of As4O6 is cleaved and an oxygen atom is added. The isolation of [K­(crypt)]2[9] raises questions as to whether [9]2– is an off-cycle product or if it has any catalytic competency. To interrogate this, 1 mol % [K­(crypt)]2[9] was tested in the hydroboration of N2O and revealed similar performance to [K­(18c6)]­[6]. Further, addition of 100 equiv of HBpin to [K­(crypt)]2[9] resulted in the formation of 7 in 14% yield, as observed by NMR spectroscopy. This is consistent with 14 HBpin molecules removing 7 oxygen atoms from [9]2–. HRMS studies of this reaction mixture showed that instead of [As7]3– being regenerated, polyarsides [As5]−, [As16]2– and [As21]3– were formed. It is expected that these polyarsides could have similar reactivity to [As7]3–, and this was confirmed by reacting the in situ-generated solution of these polyarsides with N2O, which led to the detection of [9]2– by HRMS.

Although [K­(crypt)]2[9] is found to have catalytic competency, this does not necessarily mean it is an active intermediate in the primary catalytic cycle. Structurally, it would be expected to form after several oxygen transfer reactions with N2O and, from our computational investigations, the reaction with HBpin upon installation of oxygen has a lower barrier than the reaction with more N2O to install more oxygens. Anion [9]2– is likely generated near the end of the catalytic cycle when HBpin has been consumed and there is excess N2O. Nonetheless, the catalytic competency of [K­(crypt)]2[9] and its structural relationship to As4O6 prompted the survey of commercially available pnictogen oxides in this transformation (Figure c). P4O10, As4O6, and Sb4O6 were investigated, and although P4O10 showed minimal reactivity, As4O6 and Sb4O6 both gave high conversions after 24 h, albeit at higher catalyst loadings. Furthermore, similar to the air-stable P4O10, As4O6, and Sb4O6 oxides, [K­(crypt)]2[9] was also found to be air-stable. This stability prompted us to study the reduction of N2O without predried solvents using standard bench techniques, and with 1 mol % [K­(crypt)]2[9], high conversions to 7 + 8 (91% total) were obtained.

The observation of various [Pn x ]y– and [Pn x O y ]z– structures during our mechanistic studies demonstrates the complexity of the mechanism. Many of these [Pn x ]y– and [Pn x O y ]z– type structures are expected to be present during catalysis and operate concurrently. To demonstrate that larger polypnictogens can also be catalytically active, [P16]2– was independently tested at 1 mol % loading under the optimized reaction conditions and showed intermediate performance compared to [5]3– and [6]3–. Although many of the polypnictogens generated may have some catalytic competency, we would not expect them to have the exact same efficiency. It would be expected that as structures with lower performance accumulate, overall conversions should decrease. Specifically, we expect to observe depleting catalyst recyclability as the reaction mixture is reloaded with more substrates. Recyclability studies were focused on [K­(18c6)]2[4], [K­(18c6)]3[5], and [K­(18c6)]3[6] as these were the most active systems. Using 1 mol % initial loading, good recyclability was observed up to 7 cycles, after which performance slowly decreased (Figure d). This depletion was modest and, compared to many other homogeneous catalysts reported, which often do not report on any recyclability, an added advantage. Clusters [K­(crypt)]2[9] (1 mol %), [P16]2– (1 mol %), and As4O6 (10 mol %) were also studied in similar recycling experiments, but significant loss in performance was observed after just 1 cycle. The recyclability of [K­(18c6)]2[4], [K­(18c6)]3[5], and [K­(18c6)]3[6] was further probed by applying recovered catalyst after one cycle in a separate batch reaction (see Supporting Information section 5.2). These experiments reveal that [K­(18c6)]2[4], [K­(18c6)]3[5], and [K­(18c6)]3[6] can be successfully recovered and recycled with only a slight decrease (5–10%) in the TOF compared to the first cycle. Further, previously, we have reported the ability of [Pn7]-based clusters to mediate the hydroborative reduction of CO2. , Thus, selective reduction between CO2 and N2O (∼1:1 atm) with the high-performing easily synthesized clusters [K­(18c6)]3[5] and [K­(18c6)]3[6] was tested at 1 mol % loading with HBpin (Supporting Information 6). Both catalysts were found to selectively reduce N2O, and no CO2 hydroborated products were observed by 13C­{1H} and 1H NMR spectroscopy.

Oxygen Transfer to Sulfur

Often, homogeneous catalysts that mediate N2O reduction rely on boranes or silanes to capture the oxygen, and it would be an exciting development to transfer that oxygen to build more sought-after element–oxygen bonds. Environmental scientists use sulfur-based reagents to remove the oxygen from N x O y pollutants found in wastewater and automotive exhaust, and oxidized sulfur moieties are important scaffolds in pharmaceuticals and agrochemicals. These reports motivated us to study the transfer of oxygen atoms originating from N2O to sulfur. To this end, isolated [K­(crypt)]2[9] was reacted with S8 in DMF, resulting in an immediate color change. HRMS studies of the reaction mixture revealed the presence of several arsenic sulfide species and oxidized S8 products [S7O6]2– and [S8O6]2– (Figure ). Single crystals were obtained from the reaction, and XRD studies confirmed the formation of S–O bonds, along with stretches corresponding to these bonds, observed by infrared (IR) spectroscopy. In a similar fashion, [K­(crypt)]2[9] was reacted with 1 atm of SO2, which resulted in an immediate color change, and the single crystals obtained from this reaction mixture confirmed the formation of [S2O6]2–. However, determining conversion from these reaction mixtures is difficult due to the lack of suitable NMR handles. Thus, 4-nitrophenyl disulfide [(NO2PhS)2] was reacted with [K­(crypt)]2[9] in a 1:1 ratio, and the reaction mixture was monitored by 1H and 13C­{1H} NMR spectroscopy. Near-complete consumption of (NO2PhS)2 and the formation of two new products consistent with the NMR resonances for [NO2PhSO4]− and [NO2PhSO3]− (86% and 12% conversions, respectively) were observed. Further, N2O was found to not independently react with these sulfur-based reagents. In these experiments, the oxygen that originated from N2O was transferred to arsenic, affording [9]2– and then to sulfur. These reactions are important first steps in building catalytic transformations that shuttle oxygen from N2O to build S–O bonds, but the catalytic loop here has not yet been closed.

4.

4

Open in a new tab

Oxidation of sulfur-containing compounds using [K­(crypt)]2[9].

Reduction of Nitro- Functional Groups

Beyond N2O, the reduction of other substrates featuring N–O multiple bonds was surveyed. Specifically, using 1 mol % [K­(18c6)]3[6] in oDFB the reduction of nitro-functionalized compounds (10) to amines (11) was tested (see Figure ). Initially, the reduction of nitrobenzene was targeted, and complete hydroboration was observed to afford the corresponding aminoborane 11a. Upon aqueous workup, the aniline hydrochloride salt 12a was isolated in 95% yield. The scope was expanded to substituted nitrobenzenes, and high conversion to the aminoboranes 11b–11g was observed (88–99%) with the hydrochloride salts 12b–12g isolated in high yields (74–92%). However, when 1-nitroanthracene (10h) was tested, the reaction proceeded more slowly and required heating at 100 °C overnight to reach 58% conversion to 11h. Further, substitution of the phenyl group of nitrobenzene for pyridine resulted in a decreased conversion of 76% to 11i with 12i isolated in 68% yield, while the alkyl nitro compound 2-nitropropane (10j) could be reduced with good conversion to 11j (83%) and 12j isolated in 74% yield. The aminoborane and ammonium salts isolated in this chemistry contrast with related work done by Mo et al. and Zhou et al., where nitrobenzenes are reduced to hydrazines, azoarenes, or azoxyarenes, instead of amines. ,

5.

5

Open in a new tab

Reduction of nitrocompounds using [K­(18c6)]3[6]. Reaction conditions: 1 μmol [K­(18c6)]3[6], 0.1 mmol nitro-functionalized compound, 0.5 mmol HBpin, 0.5 mL of oDFB. NMR conversion was determined by integration of the crude 1H NMR spectrum using the toluene (0.24 mmol) as the internal standard (1H δ = 2.31 ppm). Isolated yields (in parentheses) of the hydrochloride salts were obtained after aqueous workup.

Conclusion

We have studied a range of (un)­functionalized [Pn7] Zintl clusters, along with [Pn x O y ]z– clusters, in the catalytic reduction of the greenhouse gas N2O to environmentally benign N2. In general, arsenic based clusters were found to have the best performance and outperform many other homogeneous catalysts reported in related transformations. We find that the different cluster types studied offer different benefits, for example, the [Pn7]3– (Pn = P, As) catalysts can be recycled and selectively reduce N2O in the presence of CO2, while [As4O6] is commercially available and [As4O7]2– is air stable. Further, control reactions reveal that these clusters access chemistry that simple monopnictogen molecules do not. Mechanistic studies of the [P7]3– cluster indicate the possibility of an unprecedented low-valent Pn(−1)/Pn­(+1) redox couple, and initial efforts have been made to build useful sulfur–oxygen bonds using the oxygen from N2O, with future work focused on closing this catalytic loop. Beyond N2O, the reduction of nitro-functionalized substrates to amines was successfully achieved. This work represents a significant advancement in catalysis and cluster chemistry, with the mediation of difficult and underdeveloped N–O bond reductions demonstrating good performance and providing better understanding of how main group clusters offer access to chemistries beyond the purview of their noncluster counterparts.

Supplementary Material

ja5c09618_si_001.pdf (9.9MB, pdf)
ja5c09618_si_002.xlsx (55.6KB, xlsx)

Acknowledgments

We thank the University of Oxford and UKRI for funding (EP/Y037391/1) and supporting M.M. and B.v.I. We thank the University of Manchester and EPSRC for supporting R. L.-R. on a departmental studentship. We are also grateful to the University of Manchester for computing resources via its Computational Shared Facility and associated support services. We thank Gareth Smith for mass spectrometric analyses, Anne Davies and Martin Jennings for elemental analyses, and Nick Rees for NMR spectroscopic inquiries.

Glossary

ABBREVIATIONS

FLPs

frustrated Lewis pair

18c6

18-crown-6; HBpin, pinacole borane

DMF

dimethylformamide

NMR

nuclear magnetic resonance

TOF

turnover frequency

crypt

[2.2.2]­cryptand

ESM

Energetic Span Model

The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/jacs.5c09618.

  • Supplemental experimental procedures, synthesis and characterization data, catalytic reactions, reactivity studies, and computational details (PDF)

  • Coordinates of optimized structures (XLSX)

EPSRC studentship (R.L.-R.), Horizon Europe Guarantee (EP/Y037391/1), originally funded as an ERC Starting Grant.

The authors declare no competing financial interest.

References

  1. a Genoux A., Severin K.. Nitrous Oxide as Diazo Transfer Reagent. Chem. Sci. 2024;15(34):13605–13617. doi: 10.1039/D4SC04530K. [DOI] [PMC free article] [PubMed] [Google Scholar]; b Stanley J. S., Wang X. S., Yang J. Y.. Selective Electrocatalytic Reduction of Nitrous Oxide to Dinitrogen with an Iron Porphyrin Complex. ACS Catal. 2023;13(19):12617–12622. doi: 10.1021/acscatal.3c02707. [DOI] [Google Scholar]; c Ravishankara A. R., Daniel J. S., Portmann R. W.. Nitrous Oxide as Diazo Transfer Reagent Selective Electrocatalytic Reduction of Nitrous Oxide to Dinitrogen with an Iron Porphyrin Complex Nitrous Oxide (N2O): The Dominant Ozone-Depleting Substance Emitted in the 21st Century. Science. 2009;326(5949):123–125. doi: 10.1126/science.1176985. [DOI] [PubMed] [Google Scholar]
  2. a Thiemens M. H., Trogler W. C.. Nylon Production: An Unknown Source of Atmospheric Nitrous Oxide. Science. 1991;251(4996):932–934. doi: 10.1126/science.251.4996.932. [DOI] [PubMed] [Google Scholar]; b Bremner J. M., Blackmer A. M.. Nitrous Oxide: Emission from Soils During Nitrification of Fertilizer Nitrogen. Science. 1978;199(4326):295–296. doi: 10.1126/science.199.4326.295. [DOI] [PubMed] [Google Scholar]
  3. Lehnert N., Dong H. T., Harland J. B., Hunt A. P., White C. J.. Reversing Nitrogen Fixation. Nat. Rev. Chem. 2018;2(10):278–289. doi: 10.1038/s41570-018-0041-7. [DOI] [Google Scholar]
  4. a Zeng R., Feller M., Ben-David Y., Milstein D.. Hydrogenation and Hydrosilylation of Nitrous Oxide Homogeneously Catalyzed by a Metal Complex. J. Am. Chem. Soc. 2017;139(16):5720–5723. doi: 10.1021/jacs.7b02124. [DOI] [PMC free article] [PubMed] [Google Scholar]; b Ortega-Lepe I., Sánchez P., Santos L. L., Lara P., Rendón N., López-Serrano J., Salazar-Pereda V., Álvarez E., Paneque M., Suárez A.. Catalytic Nitrous Oxide Reduction with H2 Mediated by Pincer Ir Complexes. Inorg. Chem. 2022;61(46):18590–18600. doi: 10.1021/acs.inorgchem.2c02963. [DOI] [PMC free article] [PubMed] [Google Scholar]; c Jurt P., Abels A. S., Gamboa-Carballo J. J., Fernández I., Le Corre G., Aebli M., Baker M. G., Eiler F., Müller F., Wörle M.. et al. Reduction of Nitrogen Oxides by Hydrogen with Rhodium­(I)–Platinum­(II) Olefin Complexes as Catalysts. Angew. Chem., Int. Ed. 2021;60(48):25372–25380. doi: 10.1002/anie.202109642. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. a Chen X., Wang H., Du S., Driess M., Mo Z.. Deoxygenation of Nitrous Oxide and Nitro Compounds Using Bis­(N-Heterocyclic Silylene)­Amido Iron Complexes as Catalysts. Angew. Chem. 2022;134(7):e202114598. doi: 10.1002/ange.202114598. [DOI] [PubMed] [Google Scholar]; b Hood T. M., Charman R. S. C., Liptrot D. J., Chaplin A. B.. Copper­(I) Catalysed Diboron(4) Reduction of Nitrous Oxide. Angew. Chem., Int. Ed. 2024;63(45):e202411692. doi: 10.1002/anie.202411692. [DOI] [PubMed] [Google Scholar]
  6. Bermejo J., Ortega-Lepe I., Santos L. L., Rendón N., López-Serrano J., Álvarez E., Suárez A.. Nitrous Oxide Activation by Picoline-Derived Ni–CNP Hydrides. Chem. Commun. 2024;60(12):1575–1578. doi: 10.1039/D3CC05455A. [DOI] [PubMed] [Google Scholar]
  7. a Severin K.. Synthetic Chemistry with Nitrous Oxide. Chem. Soc. Rev. 2015;44(17):6375–6386. doi: 10.1039/C5CS00339C. [DOI] [PubMed] [Google Scholar]; b Parmon V. N., Panov G. I., Uriarte A., Noskov A. S.. Nitrous Oxide in Oxidation Chemistry and Catalysis: Application and Production. Catal. Today. 2005;100(1):115–131. doi: 10.1016/j.cattod.2004.12.012. [DOI] [Google Scholar]; c Corona T., Company A.. Nitrous Oxide Activation by a Cobalt­(ii) Complex for Aldehyde Oxidation Under Mild Conditions. Dalton Trans. 2016;45(37):14530–14533. doi: 10.1039/C6DT01704E. [DOI] [PubMed] [Google Scholar]; d Yamamoto A., Kitazume S., Pu L. S., Ikeda S.. Synthesis and Properties of Hydridodinitrogentris­(triphenylphosphine)­cobalt­(I) and the Related Phosphine-Cobalt Complexes. J. Am. Chem. Soc. 1971;93(2):371–380. doi: 10.1021/ja00731a012. [DOI] [Google Scholar]; e Yamada T., Hashimoto K., Kitaichi Y., Suzuki K., Ikeno T.. Nitrous Oxide Oxidation of Olefins Catalyzed by Ruthenium Porphyrin Complexes. Chem. Lett. 2001;30(3):268–269. doi: 10.1246/cl.2001.268. [DOI] [Google Scholar]; f Zeng R., Feller M., Diskin-Posner Y., Shimon L. J. W., Ben-David Y., Milstein D.. CO Oxidation by N2O Homogeneously Catalyzed by Ruthenium Hydride Pincer Complexes Indicating a New Mechanism. J. Am. Chem. Soc. 2018;140(23):7061–7064. doi: 10.1021/jacs.8b03927. [DOI] [PMC free article] [PubMed] [Google Scholar]; g Yonke B. L., Reeds J. P., Zavalij P. Y., Sita L. R.. Catalytic Degenerate and Nondegenerate Oxygen Atom Transfers Employing N2O and CO2 and a MII/MIV Cycle Mediated by Group|6 MIV Terminal Oxo Complexes. Angew. Chem., Int. Ed. 2011;50(51):12342–12346. doi: 10.1002/anie.201106074. [DOI] [PubMed] [Google Scholar]; h Yamada T., Suzuki K., Hashimoto K., Ikeno T.. N2O Oxidation of Phosphines Catalyzed by Low-Valent Nickel Complexes. Chem. Lett. 1999;28(10):1043–1044. doi: 10.1246/cl.1999.1043. [DOI] [Google Scholar]; i Saito S., Ohtake H., Umezawa N., Kobayashi Y., Kato N., Hirobe M., Higuchi T.. Nitrous Oxide Reduction-Coupled Alkene–Alkene Coupling Catalysed by Metalloporphyrins. Chem. Commun. 2013;49(79):8979–8981. doi: 10.1039/c3cc43912g. [DOI] [PubMed] [Google Scholar]; j Gianetti T. L., Annen S. P., Santiso-Quinones G., Reiher M., Driess M., Grützmacher H.. Nitrous Oxide as a Hydrogen Acceptor for the Dehydrogenative Coupling of Alcohols. Angew. Chem., Int. Ed. 2016;55(5):1854–1858. doi: 10.1002/anie.201509288. [DOI] [PubMed] [Google Scholar]; k Nappen S. T., Gamboa-Carballo J. J., Tschanen E., Ricatto F., Wörle M. D., Thomas A., Trincado M., Grützmacher H.. Water Serving as Cocatalyst for the Highly Efficient Homogeneously Catalyzed Conversion of N2O/H2 Mixtures with Optimized Rhodium NHC Complexes. Angew. Chem. 2025;137(25):e202502616. doi: 10.1002/ange.202502616. [DOI] [PubMed] [Google Scholar]
  8. Otten E., Neu R. C., Stephan D. W.. Complexation of Nitrous Oxide by Frustrated Lewis Pairs. J. Am. Chem. Soc. 2009;131(29):9918–9919. doi: 10.1021/ja904377v. [DOI] [PubMed] [Google Scholar]
  9. Lipshultz J. M., Li G., Radosevich A. T.. Main Group Redox Catalysis of Organopnictogens: Vertical Periodic Trends and Emerging Opportunities in Group 15. J. Am. Chem. Soc. 2021;143(4):1699–1721. doi: 10.1021/jacs.0c12816. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. a Neu R. C., Otten E., Stephan D. W.. Bridging Binding Modes of Phosphine-Stabilized Nitrous Oxide to Zn­(C6F5)­2. Angew. Chem. Int. Ed. 2009;48(51):9709–9712. doi: 10.1002/anie.200905650. [DOI] [PubMed] [Google Scholar]; b Kelly M. J., Gilbert J., Tirfoin R., Aldridge S.. Frustrated Lewis Pairs as Molecular Receptors: Colorimetric and Electrochemical Detection of Nitrous Oxide. Angew. Chem. Int. Ed. 2013;52(52):14094–14097. doi: 10.1002/anie.201308475. [DOI] [PubMed] [Google Scholar]; c Ménard G., Hatnean J. A., Cowley H. J., Lough A. J., Rawson J. M., Stephan D. W.. C–H Bond Activation by Radical Ion Pairs Derived from R3P/Al­(C6F5)3 Frustrated Lewis Pairs and N2O. J. Am. Chem. Soc. 2013;135(17):6446–6449. doi: 10.1021/ja402964h. [DOI] [PubMed] [Google Scholar]; d Mo Z., Kolychev E. L., Rit A., Campos J., Niu H., Aldridge S.. Facile Reversibility by Design: Tuning Small Molecule Capture and Activation by Single Component Frustrated Lewis Pairs. J. Am. Chem. Soc. 2015;137(38):12227–12230. doi: 10.1021/jacs.5b08614. [DOI] [PubMed] [Google Scholar]; e Tskhovrebov A. G., Solari E., Wodrich M. D., Scopelliti R., Severin K.. Covalent Capture of Nitrous Oxide by N-Heterocyclic Carbenes. Angew. Chem., Int. Ed. 2012;51(51):232–234. doi: 10.1002/anie.201106589. [DOI] [PubMed] [Google Scholar]; f Tskhovrebov A. G., Solari E., Wodrich M. D., Scopelliti R., Severin K.. Sequential N–O and N–N Bond Cleavage of N-Heterocyclic Carbene-Activated Nitrous Oxide with a Vanadium Complex. J. Am. Chem. Soc. 2012;134(3):1471–1473. doi: 10.1021/ja210976a. [DOI] [PubMed] [Google Scholar]; g Tskhovrebov A. G., Vuichoud B., Solari E., Scopelliti R., Severin K.. Adducts of Nitrous Oxide and N-Heterocyclic Carbenes: Syntheses, Structures, and Reactivity. J. Am. Chem. Soc. 2013;135(25):9486–9492. doi: 10.1021/ja4030287. [DOI] [PubMed] [Google Scholar]; h Tskhovrebov A. G., Naested L. C. E., Solari E., Scopelliti R., Severin K.. Synthesis of Azoimidazolium Dyes with Nitrous Oxide. Angew. Chem., Int. Ed. 2015;54(4):1289–1292. doi: 10.1002/anie.201410067. [DOI] [PubMed] [Google Scholar]
  11. Anthore-Dalion L., Nicolas E., Cantat T.. Catalytic Metal-Free Deoxygenation of Nitrous Oxide with Disilanes. ACS Catal. 2019;9(12):11563–11567. doi: 10.1021/acscatal.9b04434. [DOI] [Google Scholar]
  12. Pang Y., Leutzsch M., Nöthling N., Cornella J.. Catalytic Activation of N2O at a Low-Valent Bismuth Redox Platform. J. Am. Chem. Soc. 2020;142(46):19473–19479. doi: 10.1021/jacs.0c10092. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Lei B., Cao F., Chen M., Wang X., Mo Z.. Bisgermylene-Stabilized Stannylone: Catalytic Reduction of Nitrous Oxide and Nitro Compounds via Element-Ligand Cooperativity. J. Am. Chem. Soc. 2024;146(26):17817–17826. doi: 10.1021/jacs.4c03227. [DOI] [PubMed] [Google Scholar]
  14. Mehta M.. Zintl Clusters as Catalytic Tools for Synthesis. Trends Chem. 2024;6(7):349–351. doi: 10.1016/j.trechm.2024.04.002. [DOI] [Google Scholar]
  15. Pelletier J. D. A., Basset J.-M.. Catalysis by Design: Well-Defined Single-Site Heterogeneous Catalysts. Acc. Chem. Res. 2016;49(4):664–677. doi: 10.1021/acs.accounts.5b00518. [DOI] [PubMed] [Google Scholar]
  16. a Zhang H., Zhang Y., Zhang Y., Li H., Ou M., Yu Y., Zhang F., Yin H., Mao Z., Mei L.. Catalytic Activity of Violet Phosphorus-Based Nanosystems and the Role of Metabolites in Tumor Therapy. Nat. Commun. 2024;15(1):6783. doi: 10.1038/s41467-024-50769-0. [DOI] [PMC free article] [PubMed] [Google Scholar]; b Santisouk S., Sengdala P., Jiang X., Xue X.-X., Chen K.-Q., Feng Y.. Tuning the Electrocatalytic Properties of Black and Gray Arsenene by Introducing Heteroatoms. ACS Omega. 2021;6(20):13124–13133. doi: 10.1021/acsomega.1c00908. [DOI] [PMC free article] [PubMed] [Google Scholar]; c Zhang B., Chen W., Tao K., Sun Z., Li Q., Yan Q.. Assessing the Structural Diversity of Form II Red Phosphorus via Stepwise Crystal Structure Search. J. Am. Chem. Soc. 2024;146(38):26369–26378. doi: 10.1021/jacs.4c09250. [DOI] [PubMed] [Google Scholar]; d Fung C.-M., Er C.-C., Tan L.-L., Mohamed A. R., Chai S.-P.. Red Phosphorus: An Up-and-Coming Photocatalyst on the Horizon for Sustainable Energy Development and Environmental Remediation. Chem. Rev. 2022;122(3):3879–3965. doi: 10.1021/acs.chemrev.1c00068. [DOI] [PubMed] [Google Scholar]; e Zhou Y., Elliott S. R., Deringer V. L.. Structure and Bonding in Amorphous Red Phosphorus. Angew. Chem., Int. Ed. 2023;62(24):e202216658. doi: 10.1002/anie.202216658. [DOI] [PMC free article] [PubMed] [Google Scholar]; f Zhu Y., Ren J., Zhang X., Yang D.. Elemental Red Phosphorus-Based Materials for Photocatalytic Water Purification and Hydrogen Production. Nanoscale. 2020;12(25):13297–13310. doi: 10.1039/D0NR01748E. [DOI] [PubMed] [Google Scholar]; g Ruck M., Hoppe D., Wahl B., Simon P., Wang Y., Seifert G.. Fibrous Red Phosphorus. Angew. Chem., Int. Ed. 2005;44(46):7616–7619. doi: 10.1002/anie.200503017. [DOI] [PubMed] [Google Scholar]; h Hu Z., Lu Y., Liu M., Zhang X., Cai J.. Crystalline Red Phosphorus for Selective Photocatalytic Reduction of CO2 into CO. J. Mater. Chem. A. 2021;9(1):338–348. doi: 10.1039/D0TA09177D. [DOI] [Google Scholar]; i Zhou Y., Kirkpatrick W., Deringer V. L.. Cluster Fragments in Amorphous Phosphorus and their Evolution under Pressure. Adv. Mater. 2022;34(5):2107515. doi: 10.1002/adma.202107515. [DOI] [PubMed] [Google Scholar]; j Wang M., Xu S., Zhou Z., Dong C.-L., Guo X., Chen J.-L., Huang Y.-C., Shen S., Chen Y., Guo L.. et al. Atomically Dispersed Janus Nickel Sites on Red Phosphorus for Photocatalytic Overall Water Splitting. Angew. Chem., Int. Ed. 2022;61(29):e202204711. doi: 10.1002/anie.202204711. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Ma R., Xiong L., Jiao P., Zhou E., Jin H., Zhao Y.-Z., Zhu Y., Mei Y., Ji H., Zhang K.. et al. Origins of Severe Structural Changes during Alloying–Dealloying Reactions in Black Phosphorus. J. Am. Chem. Soc. 2024;146(33):23044–23053. doi: 10.1021/jacs.4c03691. [DOI] [PubMed] [Google Scholar]
  18. Yang Y., Zong B., Xu Q., Li Q., Li Z., Mao S.. Discriminative Analysis of NOx Gases by Two-Dimensional Violet Phosphorus Field-Effect Transistors. Anal. Chem. 2023;95(49):18065–18074. doi: 10.1021/acs.analchem.3c02894. [DOI] [PubMed] [Google Scholar]
  19. a Turbervill R. S. P., Goicoechea J. M.. From Clusters to Unorthodox Pnictogen Sources: Solution-Phase Reactivity of [E7]3– (E = P–Sb) Anions. Chem. Rev. 2014;114(21):10807–10828. doi: 10.1021/cr500387w. [DOI] [PubMed] [Google Scholar]; b van IJzendoorn B., Mehta M.. Frontiers in the Solution-Phase Chemistry of Homoatomic Group 15 Zintl Clusters. Dalton Trans. 2020;49(42):14758–14765. doi: 10.1039/D0DT02890H. [DOI] [PubMed] [Google Scholar]
  20. a Roughley S. D., Jordan A. M.. The Medicinal Chemist’s Toolbox: An Analysis of Reactions Used in the Pursuit of Drug Candidates. J. Med. Chem. 2011;54(10):3451–3479. doi: 10.1021/jm200187y. [DOI] [PubMed] [Google Scholar]; b Hayes K. S.. Industrial Processes for Manufacturing Amines. Appl. Catal. A: Gen. 2001;221(1-2):187–195. doi: 10.1016/S0926-860X(01)00813-4. [DOI] [Google Scholar]; c Afanasyev O. I., Kuchuk E., Usanov D. L., Chusov D.. Reductive Amination in the Synthesis of Pharmaceuticals. Chem. Rev. 2019;119(23):11857–11911. doi: 10.1021/acs.chemrev.9b00383. [DOI] [PubMed] [Google Scholar]; d Froidevaux V., Negrell C., Caillol S., Pascault J.-P., Boutevin B.. Biobased Amines: From Synthesis to Polymers; Present and Future. Chem. Rev. 2016;116(22):14181–14224. doi: 10.1021/acs.chemrev.6b00486. [DOI] [PubMed] [Google Scholar]; e Lawrence, S. A. Amines: Synthesis, Properties and Applications; Cambridge University Press, 2004. [Google Scholar]
  21. van IJzendoorn B., Albawardi S. F., Jobbins W. D., Whitehead G. F. S., McGrady J. E., Mehta M.. Transforming Carbon Dioxide into a Methanol Surrogate using Modular Transition Metal-Free Zintl ions. Nat. Commun. 2024;15(1):10030. doi: 10.1038/s41467-024-54277-z. [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. Knapp C., Zhou B., Denning M. S., Rees N. H., Goicoechea J. M.. Reactivity Studies of Group 15 Zintl Ions Towards Homoleptic Post-Transition Metal Organometallics: A ‘Bottom-Up’ Approach to Bimetallic Molecular Clusters. Dalton Trans. 2010;39(2):426–436. doi: 10.1039/B911544G. [DOI] [PubMed] [Google Scholar]
  23. van Ijzendoorn B., Albawardi S. F., Vitorica-Yrezabal I. J., Whitehead G. F. S., McGrady J. E., Mehta M.. A Zintl Cluster for Transition Metal-Free Catalysis: CO Bond Reductions. J. Am. Chem. Soc. 2022;144(46):21213–21223. doi: 10.1021/jacs.2c08559. [DOI] [PMC free article] [PubMed] [Google Scholar]
  24. a van Ijzendoorn B., Whittingham J. B. M., Whitehead G. F. S., Kaltsoyannis N., Mehta M.. A Robust Zintl Cluster for the Catalytic Reduction of Pyridines, Imines and Nitriles. Dalton Trans. 2023;52(38):13787–13796. doi: 10.1039/D3DT02896H. [DOI] [PubMed] [Google Scholar]; b Réant B. L. L., Mehta M.. Zintl Ions and Phases Promote the Catalytic Hydrophosphination of Alkynes, Alkenes, and Imines. Organometallics. 2024;43(3):395–401. doi: 10.1021/acs.organomet.3c00494. [DOI] [PMC free article] [PubMed] [Google Scholar]
  25. Baudler M., Floruss A.. Beiträge zur Chemie des Phosphors. 233. Li3P7O3 und Li2HP7O2 – die ersten Oxido-heptaphosphane(3) Z. Anorg. Allg. Chem. 1995;621(2):207–212. doi: 10.1002/zaac.19956210208. [DOI] [Google Scholar]
  26. Jobbins W. D., Cullen R. T., Stott T., van IJzendoorn B., Réant B. L. L., Johnstone T. C., Mehta M.. Reactivity of Tetrel-Functionalized Heptaphosphane Clusters toward Azides. Inorg. Chem. 2024;63(30):13807–13814. doi: 10.1021/acs.inorgchem.4c02264. [DOI] [PMC free article] [PubMed] [Google Scholar]
  27. a Moon H. W., Cornella J.. Bismuth Redox Catalysis: An Emerging Main-Group Platform for Organic Synthesis. ACS Catal. 2022;12(2):1382–1393. doi: 10.1021/acscatal.1c04897. [DOI] [PMC free article] [PubMed] [Google Scholar]; b Mato M., Cornella J.. Bismuth in Radical Chemistry and Catalysis. Angew. Chem., Int. Ed. 2024;63(8):e202315046. doi: 10.1002/anie.202315046. [DOI] [PubMed] [Google Scholar]
  28. a Turbervill R. S. P., Goicoechea J. M.. Hydrophosphination of Carbodiimides Using Protic Heptaphosphide Cages: A Unique Effect of the Bimodal Activity of Protonated Group 15 Zintl Ions. Organometallics. 2012;31(6):2452–2462. doi: 10.1021/om300072z. [DOI] [Google Scholar]; b Turbervill R. S. P., Goicoechea J. M.. Hydropnictination Reactions of Carbodiimides and Isocyanates with Protonated Heptaphosphide and Heptaarsenide Zintl Ions. Eur. J. Inorg. Chem. 2014;2014(10):1660–1668. doi: 10.1002/ejic.201301011. [DOI] [Google Scholar]
  29. Pertlik F.. Strukturverfeinerung von Kubischem As2O3 (Arsenolith) mit Einkristalldaten. Czech. J. Phys. B. 1978;28(2):170–176. doi: 10.1007/BF01591036. [DOI] [Google Scholar]
  30. a Huang S., Zheng Z., Wei Q., Han I., Jaffé P. R.. Performance of Sulfur-Based Autotrophic Denitrification and Denitrifiers for Wastewater Treatment Under Acidic Conditions. Bioresour. Technol. 2019;294:122176. doi: 10.1016/j.biortech.2019.122176. [DOI] [PubMed] [Google Scholar]; b Chen Z., Lou M., Fang P., Xiao D., Zhu W., Chen H., Qian W.. Impact of Different Sulfur Sources on the Structure and Function of Sulfur Autotrophic Denitrification Bacteria. Sci. Rep. 2023;13(1):19404. doi: 10.1038/s41598-023-46829-y. [DOI] [PMC free article] [PubMed] [Google Scholar]
  31. a Feng M., Tang B., Liang S. H., Jiang X.. Sulfur Containing Scaffolds in Drugs: Synthesis and Application in Medicinal Chemistry. Curr. Top. Med. Chem. 2016;16(11):1200–1216. doi: 10.2174/1568026615666150915111741. [DOI] [PMC free article] [PubMed] [Google Scholar]; b Du S., Hu X., Lindsley C. W., Zhan P.. New Applications of Sulfonyl Fluorides: A Microcosm of the Deep Integration of Chemistry and Biology in Drug Design. J. Med. Chem. 2024;67(19):16925–16927. doi: 10.1021/acs.jmedchem.4c02112. [DOI] [PubMed] [Google Scholar]; c Matos P. M., Stockman R. A.. Synthetic Approaches and Applications of Sulfonimidates. Org. Biomol. Chem. 2020;18(33):6429–6442. doi: 10.1039/D0OB01191F. [DOI] [PubMed] [Google Scholar]; d Jeanguenat A., Lamberth C.. Sulfur-Based Functional Groups in Agrochemistry. Pest Manag. Sci. 2023;79(8):2647–2663. doi: 10.1002/ps.7553. [DOI] [PubMed] [Google Scholar]
  32. Zhang Z., Li K., Huang M., Chen T., Zhou J.. The Outstanding Ambiphilicity of Trialkylstibines among Trialkylpnictines: Power for Stepwise Deoxygenation and N–N Coupling of Nitroarenes. J. Am. Chem. Soc. 2025;147(12):10066–10072. doi: 10.1021/jacs.5c01964. [DOI] [PubMed] [Google Scholar]

Associated Data

This section collects any data citations, data availability statements, or supplementary materials included in this article.

Supplementary Materials

ja5c09618_si_001.pdf (9.9MB, pdf)
ja5c09618_si_002.xlsx (55.6KB, xlsx)

Articles from Journal of the American Chemical Society are provided here courtesy of American Chemical Society

RESOURCES