MoS<Subscript>2</Subscript> single slab as a model for active component of hydrodesulfuration catalyst: a quantum chemical study 1. Molecular and electronic structure of Mo<Subscript>12</Subscript>S<Subscript>24</Subscript> macromolecule and its adsorption complex with H<Subscript>2</Subscript>S

The molecular and electronic structure of Mo₁₂S₂₄ macromolecule as the MoS₂ single slab structure was calculated by the density functional theory (DFT) method with the B3P86 hybrid exchange-correlation functional. The results of calculations point to slight relaxation of coordinatively unsaturated Mo and S atoms, which is consistent with the published data. The calculated width of the forbidden band (0.85–0.98 eV) is comparable with the experimental value (1.30 eV) and similar to that obtained from DFT calculations with periodic boundary conditions (0.89 eV). The surface Mo centers in the Mo₁₂S₂₄ macromolecule are more reduced than the internal (Mo^IV) atoms. In order to characterize the adsorption capacity of coordinatively unsaturated Mo centers, a Mo₁₂S₂₄·6H₂S adsorption complex was calculated. The structure and energy characteristics of the adsorption complex point to a weak donor-acceptor interaction of the π-lone pair of H₂S molecule with the surface (reduced) Mo centers. The active center of thiophene hydrodesulfuration catalysts is formed as a result of the oxidative addition of hydrogen followed by occlusion of hydrogen into the MoS₂ matrix. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2189–2193, October, 2005.     

Dimeric [Mo2S12]2− Cluster: A Molecular Analogue of MoS2 Edges for Superior Hydrogen‐Evolution Electrocatalysis

Proton reduction is one of the most fundamental and important reactions in nature. MoS₂ edges have been identified as the active sites for hydrogen evolution reaction (HER) electrocatalysis. Designing molecular mimics of MoS₂ edge sites is an attractive strategy to understand the underlying catalytic mechanism of different edge sites and improve their activities. Herein we report a dimeric molecular analogue [Mo₂S₁₂]^2?, as the smallest unit possessing both the terminal and bridging disulfide ligands. Our electrochemical tests show that [Mo₂S₁₂]^2? is a superior heterogeneous HER catalyst under acidic conditions. Computations suggest that the bridging disulfide ligand of [Mo₂S₁₂]^2? exhibits a hydrogen adsorption free energy near zero (?0.05 eV). This work helps shed light on the rational design of HER catalysts and biomimetics of hydrogen‐evolving enzymes.     

The performance of a Ru?Mo sulfide catalyst for H2S decomposition

A γ-alumina-supported bimetallic Ru-Mo sulfide catalyst preparedvia precipitation from homogeneous solution (PFHS) has been used to effect the abstraction of H₂ from H₂S. The decomposition reaction was also carried out over Al₂O₃-supported RuS₂ and MoS₂ catalysts synthesizedvia PFHS. The performance of bimetallic system exceeded (ca. 40%) the simple additive activities of the constituent monometallic sulfide catalysts and about 2–3 times the individual activities of the monometallic sulfide samples, suggesting chemical synergism between Ru and Mo in the Ru-Mo catalyst. In particular, comparison with other catalysts in the literature showed that specimens preparedvia PFHS exhibited better activities than those from direct sulfidation of the metal oxide. Kinetic study over the Ru-Mo bimetallic sulfide catalyst in a quartz micro-reactor at 110 kPa and between 783–973 K revealed a 1st order dependency on H₂S partial pressure and an activation energy of about 92 kJ mol⁻¹. The irreversible adsorption of H₂S on a coordinatively unsaturated site is thought to be the rate-limiting step.     

Darstellung der supraleitenden ternären Phase PbMo6S8 durch chemischen Transport

Preparation of the Superconducting Ternary Phase PbMo₆S₈ by Chemical Transport Reactions The only ternary phase existing in the system Pb? Mo? S is the superconducting compound Pb_xMo₆S_y (PMS). It can be transported by CTR using PbBr₂ if an equilibrium mixture of PMS and Mo is present at the starting side, or if there is the pure PMS phase not exceeding a critical sulphur content. The transport conditions were deduced from a thermodynamical analysis of the system Pb? Mo? S? Br. Now it can be stated that all condensed phases occuring in the Pb? Mo? S system can be deposited from vapour phase by CTR or by sublimation: Pb, Mo, S, PbS, Mo₂S₃, MoS₂, PMS.     

Formation of novel molybdenum and tungsten sulfides by reduction of MoS2 and WS2: A new route to chevrel phases

Pt-catalyzed hydrogen reduction of MoS₂ and WS₂ at 1000–1050°C yields new metal-rich sulfidesM₂₁S₈ andM₁₄S₅ (M =Mo or W). The reduction of MoS₂ proceeds via the intermediate Mo₆S₈. Chevrel phases, Cu_xMo₆S₈(x < 4.0) and Ni₂Mo₆S₈, are readily prepared by hydrogen reduction of MoS₂ in the presence of the ternary metal.     

Electrolysis of solid MoS2 in molten CaCl2 for Mo extraction without CO2 emission

Sintered (300 °C) porous pellets of MoS₂ were electrolysed to elemental S and Mo in molten CaCl₂ (800–900 °C) under argon at 1.0–3.0 V for 1–20 h. On a graphite anode, the product was primarily S (but traces of CS₂ could not yet be excluded by this work) and evaporated from the molten salt, allowing the electrolysis to continue. It then condensed to solid at the lower temperature regions of the system. The anode remained intact after repeated uses. The MoS₂ pellet was highly conducting at high temperatures and could be fast electro-reduced to fine Mo powders (0.1–1.0 μm) in which the S content could be below 1000 ppm. No reduction occurred at voltages below 0.5 V. Partial reduction was seen at 0.5–0.7 V, and converted MoS₂ to a mixture of MoS₂ and Mo₃S₄, or Mo₃S₄ and Mo with the Mo content increasing with the voltage. Cyclic voltammetry of the MoS₂ powder in a Mo-cavity electrode, together with the electrolysis results, revealed the reduction mechanism to include two steps: MoS₂ to Mo₃S₄ at −0.28 V (potential vs. Ag/AgCl), and then to Mo at −0.43 V.     

How to find an optimum cluster size through topological site properties: MoSxmodel clusters

Computational investigations in catalysis frequently use model clusters to represent realistically the catalyst and its reaction sites. Detailed knowledge of the molecular charge, thus electronic density, of a cluster would then allow physical and chemical insights of properties and can provide a procedure to establish their optimum size for catalyst studies. For this purpose, an approach is suggested to study model clusters based on the distributed multipole analysis (DMA) of molecular charge properties. After full density functional theory (DFT) geometry optimization of each cluster, DMA computed from the converged DFT one‐electron density matrix allowed the partition of the corresponding cluster charge distribution into monopole, dipole, and quadrupole moments on the atomic sites. The procedure was applied to MoS₂ model clusters Mo₁₀S₁₈, Mo₁₂S₂₆, Mo₁₆S₃₂, Mo₂₃S₄₈, and Mo₂₇S₅₄. This analysis provided detailed features of the charge distribution of each cluster, focused on the 101 0 (Mo or metallic edge) and 1 010 (sulfur edge) active planes. Properties of the Mo₂₇S₅₄ cluster, including the formation of HDS active surfaces, were extensively discussed. The effect of cluster size on the site charge distribution properties of both planes was evaluated. The results showed that the Mo₁₆S₃₂ cluster can adequately model both active planes of real size Mo₂₇S₅₄. These results can guide future computational studies of MoS₂ catalytic processes. Furthermore, this approach is of general applicability. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011     

Two novel molybdenum complexes containing [Mo2O2S2]2+ fragment: synthesis,crystal structures and catalytic studies

Mo₂O₂S₂(HGly)(Gly)₂ 1 and K₆[Mo₂O₂S₂(nta)₂][Mo₂O₂S₂(ntaH)₂]^·4H₂O 2 were synthesized by the reactions of (NH₄)₂MoS₄ and amino acids L (L = glycine, nitrilotriacetic acid) in ethanol–water medium at ambient temperature. The two complexes were characterized by elemental analysis, infrared spectra, UV–visible spectra, TG–DTA and XPS. X‐ray crystallographic structural analyses revealed that compound 1 is a binuclear Mo? S? glycinate complex, a glycinate ligand is coordinated to each molybdenum atom through its amine nitrogen and carboxylato oxygen, respectively, and the third glycinate acts as a bridge through its two carboxylato oxygens linking the two molybdenum atoms. Compound 2 is also a binuclear Mo? S complex with two nitrilotriacetate ligands, each of which is coordinated to a molybdenum atom via its two β‐carboxylato oxygens and a nitrogen atom. Simultaneously, each molybdenum atom in 1 and 2 is chelated to a terminal oxygen and two bridging sulfurs to complete the octahedral configuration. Their catalytic activities in the reduction from C₂H₂ to C₂H₄ as well as other binuclear Mo? S? polycarboxylate complexes, a [Fe₄S₄] single cubane and a chainlike Mo? Fe? S compound were investigated and it was found that 1 exhibited relatively good catalytic activity. Copyright © 2007 John Wiley & Sons, Ltd.     

Crystal structure of tetraethylammonium bis(tetracarbonylmolybdenum)-tetrathiotungstate, [EtN][(OC)MoSWSMo(CO)] and synthesis, infrared spectra, 95 Mo NMR spectra and cyclic voltammetry of new linear trinuclear Mo(W)–S carbonyl clusters containing mixed-valence metal atoms [(OC)MSM′SM(CO)]− (M, M′=Mo or W)

Four trinuclear molybdenum(tungsten)-sulfur carbonyl cluster compounds, [Et₄N]₂[(OC)₄Mo-S₂MoS₂Mo(CO)₄] (1), [Et₄N]₂[(OC)₄WS₂WS₂W(CO)₄] (2), [Et₄N]₂[(OC)₄MoS₂WS₂Mo(CO)₄] (3), [Et₄N]₂[(OC)₄WS₂MoS₂W(CO)₄] (4) have been prepared by both reaction of [M(CO)₄(S₂CNEt₂)]⁻ with M′S₄²− in MeOH and reaction of MeCN solution of M(CO)₆ with M′S₄²− in MeOH (M=Mo, W; M′=Mo, W). These complexes has been characterized by routine elemental analysis and spectroscopy and the structures of 1 and 3 have been determined by X-ray crystallography. The structure study reveals that the anion of 3 contains a heteronuclear Mo–W–S trimetallic core, [MoS₂WS₂Mo]²−, consisting of two perpendicular rhombic MoS₂W units sharing a tungsten atom. The Mo–W bond distances are 3.028(2) and 3.031(2) Å and the Mo–W–Mo angle is 176.04(5)°. The average bond lengths of W–S and Mo–S are 2.21 and 2.54 Å, respectively. The X-ray, structure, IR, CV (cyclic voltammetry) and 95 Mo NMR studies on these four cluster complexes indicated that these cluster complexes possess wide separated oxidation states of metal atoms and exhibit the charge transfer, M^L→M^HS₄ (M^L represents a low-valance metal atom and M^H a high valence metal atom), between the two different valence metallic centers in the cluster complexes. It has been found that the charge transfer, M^L→M^HS₄, in the complexes are: 1>4, 3>2, 1>3, 4>2, 1>2 and 34 implying the electron-donation ability of low-valence metal atoms in the complexes is Mo⁰>W⁰ and the electron-accepted ability of the high valence metal atoms in the complexes is Mo^VI>W^VI.     

Cs2Mo15S19: a novel ternary reduced molybdenum sulfide containing Mo6 and Mo9 clusters

The crystal structure of dicaesium pentadecamolybdenum nonadeca­sulfide, Cs₂Mo₁₅S₁₉, consists of a mixture of Mo₆S₈S₆ and Mo₉S₁₁S₆ cluster units in a 1:1 ratio. Both units are interconnected via inter‐unit Mo—S bonds. The Cs⁺ cations occupy large voids between the different cluster units. The Cs and two inner S atoms lie on sites with 3 symmetry (Wyckoff site 12c) and the Mo and S atoms of the median plane of the Mo₉S₁₁S₆ cluster unit on sites with 2 symmetry (Wyckoff site 18e).     

Electronic Properties of Triangle Molybdenum Disulfide (MoS2) Clusters with Different Sizes and Edges

The electronic structures and transition properties of three types of triangle MoS₂ clusters, A (Mo edge passivated with two S atoms), B (Mo edge passivated with one S atom), and C (S edge) have been explored using quantum chemistry methods. The highest occupied molecular orbital (HOMO)–lowest unoccupied molecular orbital (LUMO) gap of B and C is larger than that of A, due to the absence of the dangling of edge S atoms. The frontier orbitals (FMOs) of A can be divided into two categories, edge states from S_3p at the edge and hybrid states of Mo_4d and S_3p covering the whole cluster. Due to edge/corner states appearing in the FMOs of triangle MoS₂ clusters, their absorption spectra show unique characteristics along with the edge structure and size.     

Mehrkernige Molybdän- und Wolframkomplexe mit Schwefel- und Dithiophosphinatoliganden

Polynuclear Molybdenum and Tungsten Complexes with Sulfur and Dithiophosphinato Ligands Reaction of Mo(CO)₆ and disulfane [R₂P(S)]₂S₂ (R: Et, Pr, Bu) gives disulfidobridged cluster chelates [Mo₃S₇(R₂PS₂)₃]⁺ [R₂PS₂]^? 1 , the anions of which can be easily exchanged. From 1 and Ph₃P sulfido-bridged non-electrolytes [Mo₃S₄(R₂PS₂)₄] 2 are obtained, in which two Mo are additionally bridged by one R₂PS₂^?. By treatment of 2 with S₈ or disulfane 1 is regenerated. As in the conversion 1 ? 2 the formal oxidation state of Mo remains unchanged this process can be reduced to the redox reaction S₂^2? ? 1/8 S₈ + S^2?, which takes place under maintenance of the Mo₃ skeleton. Compounds 2 are coordinatively unsaturated and give 1:1 adducts with pyridine. Under modified reaction conditions M(CO)₆ and disulfane form binuclear complexes Mo₂S₄(R₂PS₂)₂ 3 resp. W₂S₄(R₂PS₂)₂ 4 , of which only 3 undergoes further reaction with M(CO)₆ and disulfane leading to 1 . The results of structural and spectroscopic investigations are reported and discussed.     

Elucidation by computer simulations of the CUS regeneration mechanism during HDS over MoS<Subscript>2</Subscript> in combination with <Superscript>35</Superscript>S experiments

The first part of this paper is a short review of the ³⁵S radioactive tracer methods developed in recent years. Then, the experimental results obtained so far on Mo/Al₂O₃ catalysts are compared with computer simulation results recently claimed in order to elucidate the coordinatively unsaturated site (CUS) creation/replenishment/ regeneration mechanism over MoS₂ crystallites. The computer simulations allowed us to pre-select thermodynamically acceptable mechanisms among a set of suggested ones. Then, by comparison of the calculated activation energies with the ³⁵S experiments results we could further validate the most probable mechanism. This mechanism involved the dissociative adsorption of an H₂ molecule on the metallic edge of a MoS₂ crystallite surface with further creation of a CUS by release of one H₂S molecule in the gas phase. Both laboratory and computer simulated experiments permitted to calculate the activation energy for the H2S liberation reaction. In both cases, this energy was about 10- 12 kcal/mol, confirming the accuracy of the proposed mechanism. Moreover, the calculated activation energy of the rate-limiting step for the creation of one CUS by the proposed mechanism was about 23 kcal/mol, which was also in good agreement with the experimental activation energy of the dibenzothiophene (DBT) hydrodesulphurisation (HDS) reaction (typically about 20- 22 kcal/mol). This correlation indicated that the DBT HDS reaction rate might be intrinsically governed by the CUS formation/replenishment process, i.e. that the vacancy formation process is a crucial parameter in the global HDS reaction mechanism. Nevertheless, in the case of the 4,6-dimethyl DBT (4,6-DMDBT) HDS reaction, the experimental activation energy is higher (approx. 30 kcal/mol), confirming that external parameters induced by the 4,6-DMDBT-specific properties themselves are likely to play an important role in the reaction process, in addition to the ones intrinsic to the catalytic phase.     

Impedance Biosensing atop MoS2 Thin Films with Mo−S Bond Formation to Antibody Fragments Created by Disulphide Bond Reduction

Immobilization of antibody fragments to 3‐phenoxybenzoic acid (3‐PBA), which are created by disulphide bond (S?S) reduction with tris (2‐carboxyethyl) phosphine (TCEP), is reported atop MoS₂ and Cu‐doped MoS₂ thin films. MoS₂ and Cu‐doped MoS₂ thin films are electrodeposited using previously reported methods and tested for their ability to immobilize antibody fragments, before and after annealing in Ar at 500 °C for 3 h. This annealing procedure removes excess sulphur in the as‐deposited films, and creates coordinatively unsaturated Mo sites that are highly reactive towards sulphur, as previously reported for MoS₂ hydrodesulphurization catalysts. As demonstrated by electrochemical impedance spectroscopy (EIS) measurements, both annealed MoS₂ and Cu‐doped MoS₂ thin films adsorb antibody fragments through Mo?S bond formation, unlike the as‐deposited films. Impedance detection of 3‐PBA is reported utilizing antibody fragments bound to both materials, with a sensitivity of 2.7×10⁸ Ω cm² M^?1 and a detection limit of 2.5×10^?6 M atop MoS₂, and a sensitivity of 5.9×10⁸ Ω cm² M^?1 and a detection limit of 3.8×10^?6 M atop Cu‐doped MoS₂. The rms surface roughness obtained by atomic force microscopy (AFM) measurements atop annealed MoS₂ and Cu‐doped MoS₂ ranges from 60–140 nm, so the methods described herein are not limited to ultra‐smooth substrates.     

The correct formulation of the sulfur transfer reagent benzyltriethylammonium tetracosathioheptamolybdate

The recently reported sulfur transfer reagent benzyltriethylammonium tetracosathioheptamolybdate [(PhCH₂)N(C₂H₅)₃]₆[Mo₇S₂₄] [Tetrahedron Lett. 2003, 44, 887] is correctly formulated as benzyltriethylammonium tetrathiomolybdate [(PhCH₂)N(C₂H₅)₃]₂[MoS₄]. The correct formulation explains the unusual sulfur transfer properties of [(PhCH₂)N(C₂H₅)₃]₆[Mo₇S₂₄] observed in the earlier work.     

密度泛函理论研究十二烷硫醇在Au(111)面上的吸附

采用第一性原理方法研究了十二烷硫醇(C₁₂H₂₅SH)分子在Au(111)面上未解离和解离吸附的结构、能量和吸附性质,在此基础上分析判断长链硫醇分子在Au(111)面吸附时S―H键的解离, 以及分子链长度对吸附结构和能量的影响. 计算了S原子在不同位置以不同方式吸附的系列构型, 结果表明在S―H键解离前和解离后,均存在两种可能的表面结构, 直立吸附构型和平铺吸附构型; 未解离的C₁₂H₂₅SH分子倾向于吸附在top位, 吸附能为0.35-0.38 eV; H原子解离后C₁₂H₂₅S基团倾向于吸附在bri-fcc位, 吸附能量为2.01-2.09 eV. 比较分析未解离吸附和解离吸附, 发现C₁₂H₂₅SH分子未解离吸附相较于解离吸附要稳定, 未解离吸附属于弱化学吸附.局域电子态密度和差分电荷密度分析进一步验证了S―H解离后S原子与表面之间成键的数目增加, 而且键合更强. 同时我们发现长链硫醇的吸附能量较短链硫醇的吸附能量略大, S原子与表面Au原子之间的距离略小.     

X-ray absorption spectroscopy study of the electronic structure and local coordination of 1st row transition metal-promoted Chevrel-phase sulfides

Abstract

The electronic structures of S and Mo as well as the local coordination of Mo are investigated as a function of metal promotion Chevrel-phase (CP) sulfides. We observe the effect of metal promoter-induced electron donation into the stoichiometric range M_xMo₆S₈ (M?=?Fe, Ni, Cu; x?=?0–2) through analysis of X-ray absorption near-edge structure regions. We further observe the effect of this promotion on the bonding environment of Mo₆ metal centers through extended X-ray absorption fine structure analysis. We monitor expansion and contraction of Mo₆ octahedra with and without metal promotion, as has been predicted by Hückel molecular orbital theory. We further observe a marked tunability in the electronic structure of sulfur upon charge transfer between promoting species and Mo₆S₈ units. Average Mo₆ octahedron Mo–Mo bond contraction from 2.76 Å to as short as 2.69 Å was observed upon incorporation of metal promoters, while intercluster separation displays a pronounced increase for promoter-host lattices compared to un-promoted Mo₆S₈. To corroborate spectroscopically observed phenomena, we performed computational analyses of spin-polarized densities of state for the CP materials investigated herein, where a detectable increase in sulfur-based frontier orbital population is observed in accordance with experimentally validated orbital filling.     

Sc0.43(2)Rb2Mo15S19, a partially Sc‐filled variant of Rb2Mo15S19

The structure of scandium dirubidium pentadecamolybdenum nonadecasulfide, Sc_{0.43 (2)}Rb₂Mo₁₅S₁₉, constitutes a partially Sc‐filled variant of Rb₂Mo₁₅S₁₉ [Picard, Saillard, Gougeon, Noel & Potel (2000), J. Solid State Chem. 155 , 417–426]. In the two compounds, which both crystallize in the Rc space group, the structural motif is characterized by a mixture of Mo₆Sⁱ₈S^a₆ and Mo₉Sⁱ₁₁S^a₆ cluster units (`i' is inner and `a' is apical) in a 1:1 ratio. The two components are interconnected through interunit Mo—S bonds. The cluster units are centred at Wyckoff positions 6b and 6a (point‐group symmetries and 32, respectively). The Rb⁺ cations occupy large voids between the different cluster units. The Rb and the two inner S atoms lie on sites with 3. symmetry (Wyckoff site 12c), and the Mo and S atoms of the median plane of the Mo₉S₁₁S₆ cluster unit lie on sites with .2 symmetry (Wyckoff site 18e). A unique feature of the structure is a partially filled octahedral Sc site with symmetry. Extended Hückel tight‐binding calculations provide an understanding of the variation in the Mo—Mo distances within the Mo clusters induced by the increase in the cationic charge transfer due to the insertion of Sc.     

Non-Dissociative Activation of Chemisorbed Dinitrogen on One or Two Vanadium Atoms Supported by a Mo6S8 Cluster

Adsorption of N₂ on Mo₆S₈^q_V_x clusters (x=0, 1, 2; q=0, ±1) were systematically studied by density functional theory calculations with dispersion corrections. It was found that the N₂ can be chemisorbed and undergo non-dissociative activation on single or double metal atoms. The adsorption and activation are influenced by metal types (V or Mo), N₂ coordination modes and charge states of the clusters. Particularly, anionic Mo₆S₈⁻_V₂ clusters have remarkable ability to fix and activate N₂. In Mo₆S₈⁻_V₂, two V atoms prefer to adsorb on two adjacent S−Mo−S hollow sites, leading to the formation of a supported V…V unit. The N₂ is bridged side-on coordinated with these two V atoms with high adsorption energy and significant charge transfer. The bond order, bond length and vibration frequency of the adsorbed N₂ are close to those of a N−N single bond.     

The Decisive Role of Spin States and Spin Coupling in Dictating Selective O2 Adsorption in Chromium(II) Metal–Organic Frameworks**

The coordinatively unsaturated chromium(II)-based Cr₃[(Cr₄Cl)₃(BTT)₈]₂ (Cr−BTT; BTT³⁻=1,3,5-benzenetristetrazolate) metal–organic framework (MOF) has been shown to exhibit exceptional selectivity towards adsorption of O₂ over N₂/H₂. Using periodic density functional theory (DFT) calculations, we attempted to decipher the origin of this puzzling selectivity. By computing and analyzing the magnetic exchange coupling, binding energies, the partial density of states (pDOS), and adsorption isotherms for the pristine and gas-bound MOFs [(Cr₄(X)₄Cl)₃(BTT)₈]³⁻ (X=O₂, N₂, and H₂), we unequivocally established the role of spin states and spin coupling in controlling the gas selectivity. The computed geometries and gas adsorption isotherms are consistent with the earlier experiments. The binding of O₂ to the MOF follows an electron-transfer mechanism resulting in a Cr^III superoxo species (O₂^.−) with a very strong antiferromagnetic coupling between the two centers, whereas N₂/H₂ are found to weakly interact with the metal center and hence only slightly perturb the associated coupling constants. Although the gas-bound and unbound MOFs have an S=0 ground state (GS), the nature of spin the configurations and the associated magnetic exchanges are dramatically different. The binding energy and the number of oxygen molecules that can favorably bind to the Cr center were found to vary with respect to the spin state, with a significant energy margin (47.6 kJ mol⁻¹). This study offers a hitherto unknown strategy of using spin state/spin couplings to control gas adsorption selectivity in MOFs.