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In the past few years, two-dimensional (2D) high-temperature ferromagnetic semiconductor (FMS) materials with novelty and excellent properties have attracted much attention due to their potential in spintronics applications. In this work, using first-principles calculations, we predict that the H-MnN 2 monolayer with the H-MoS 2 -type structure is a stable intrinsic FMS with an indirect band gap of 0.79 eV and a high Curie temperature ( T c ) of 380 K. The monolayer also has a considerable in-plane magnetic anisotropy energy (IMAE) of 1005.70 μeV/atom, including a magnetic shape anisotropy energy induced by the dipole-dipole interaction (shape-MAE) of 168.37 μeV/atom and a magnetic crystalline anisotropy energy resulting from spin-orbit coupling (SOC-MAE) of 837.33 μeV/atom. Further, based on the second-order perturbation theory, its in-plane SOC-MAE of 837.33 μeV/atom is revealed to mainly derive from the couplings of Mn-d xz ,d yz and Mn-d x 2 - y 2 ,d xy orbitals through L z in the same spin channel. In addition, the biaxial strain and carrier doping can effectively tune the monolayer's magnetic and electronic properties. Such as, under the hole and few electrons doping, the transition from semiconductor to half-metal can be realized, and its T c can go up to 520 and 620 K under 5% tensile strain and 0.3 hole doping, respectively. Therefore, our research will provide a new, promising 2D FMS for spintronics devices., Competing Interests: The authors declare no competing financial interest., (© 2023 The Authors. Published by American Chemical Society.)

The interfacial interaction including chemical bonding or electron transfer and even physisorption in composite electrocatalysts has a considerable effect on electrocatalytic oxidation reaction. Herein, we report a tremendously enhanced catalytic activity and excellent durability for the ethanol electro-oxidation reaction in NiMoO 4 -C-supported Pd composites (Pd/NiMoO 4 -C) compared to the commercial Pd/C (10%) catalyst. The X-ray powder diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy measurements disclose that the strong electron transfer between NiMoO 4 nanorods and Pd nanoparticles likely induces the formation of more electrochemical active centers and improves the adsorption-desorption capacity of reactants and corresponding intermediates. In addition, the Pd/NiMoO 4 -C composite exhibits superior specific activity for ethanol oxidation compared to the Pd/NiMoO 4 catalyst with physically incorporated carbon black, which further reveals that the stronger anchoring effect between Pd and C and higher electrical conductivity in Pd/NiMoO 4 -C composites are also conducive to promote the ethanol oxidation reaction. These discoveries provide an effective and simple method for the design of advanced electrocatalysts and provide more insights into optimizing the electronic interaction between the catalyst and support in general.

Motivated by the predicted unusual short Ni-Ni bond length that is comparable to the intermetallic distance anticipated for the triple bond, the nature of Ni-Ni bonding interaction in the triply carbonyl-bridged geometry of the neutral Ni 2 (CO) 5 complex has been investigated using a range of state-of-the-art quantum chemistry methods. The elaborate analyses manifest that the tribridged Ni 2 (CO) 5 features triple three-center two-electron Ni-C-Ni bonds instead of Ni≡Ni triple bond. The electron pair donated by the bridging carbonyl ligand should be shared by both nickel centers to achieve the favored (18, 18) configuration.

The CO chemisorption onto the ScO + cation was investigated using infrared photodissociation spectroscopy combined with density functional theory calculations. The spectra were recorded in the CO stretching vibrational region for the OSc(CO) n + ( n = 4-6) complex series. Comparisons of the experimental spectra with the simulated ones have established the geometries and present strong evidence that all of the CO ligands are chemisorbed, which could not be readily oxidized by scandium monoxide core into CO 2 . Complementary calculations demonstrate that, regardless of the thermodynamic feasibility, the CO oxidation on the scandium monoxide carbonyl complexes is kinetically unfavorable due to the significant barriers involved in the CO oxidation process. Nevertheless, the consecutive CO adsorption has a positive influence on the Sc-O bond activation.

The series of novel rhenium(I) tricarbonyl mixed-ligand complexes Re(X)(CO)(3)(N^N) (N^N = pyridine-2-aldoxime; X = -Cl, 1; X = -CN, 2; and X = -C≡C, 3) has been investigated theoretically to explore the ligand X effect on their electronic structures and spectroscopic properties. The contribution of the X ligand to the highest occupied molecular orbital (HOMO) and HOMO-1 decreases in the order of 3 > 1 > 2, in line with the π-donating abilities of the X: -C≡C > -Cl > -CN. The reorganization energy (λ) calculations show that 1 and 3 will result in the higher efficiency of organic light-emitting diodes than 2. The lowest-lying absorptions of 1 and 3 can be assigned to the {[d(xz), d(yz)(Re) + π(CO) + π(X)] → [π* (N^N)]} transition with mixing metal-to-ligand, ligand-to-ligand, and X ligand-to-ligand charge transfer (MLCT/LLCT/XLCT) character, whereas this absorption at 354 nm (H-1 → L) of 2 is assigned to {[d(xz), d(yz)(Re) + π(CO) + π(N^N)] → [π* (N^N)]} transition with MLCT/LLCT/ILCT (intraligand charge transfer). Furthermore, the absorptions are red-shifted in the order 2, 1, and 3, with the increase of π-donating abilities of X ligands. The solvent effects cause red shifts of the absorption and emission spectra with decreasing solvent polarity.

A perfectly square-planar, D(4h)-symmetric, tetracoordinated oxygen has been observed in a tetracopper cluster-based coordination polymer that shows an unusual magnetic moment and ESR signal. The stabilization factor of the square-planar tetracoordinated oxygen has been revealed using DFT calculations., (© 2011 American Chemical Society)

The chemical fixation of carbon dioxide with 2,3-epoxypropyl phenyl ether catalyzed by LiBr salt to produce a five-membered cyclic carbonate, 4-(phenoxymethyl)-1,3-dioxolan-2-one, has been extensively investigated at the B3LYP density functional level of theory. The solvent effects have been studied by means of a PCM model. All possible pathways are examined, and their corresponding energetics are demonstrated. Our results reveal that the overall reaction comprises three main steps: epoxide ring-opening, carbon dioxide insertion, and ring-closure of cyclic carbonate, none of which contains significantly large barriers. On the basis of the computed free energies of activation, the rate-determining step can be the ring-opening of epoxide or the ring-closure of cyclic carbonate with variation in the reaction conditions in N-methylpyrrolidinone (NMP) solvent. Our calculations indicate that path 2 is more favorable than path 1 in the gas phase, while both of them exist possibly in NMP solvent. The overall reaction is exothermic. Furthermore, the free energy profiles of all reaction pathways along the minima energy path in the gas phase and in NMP solvent were obtained and compared. It is shown that NMP solvent does not change the general trends for the reaction potential energy surfaces.

A tube Ge(60)H(60) isomer in D(5d) symmetry with fused five-membered rings located at the ends of the tube is more stable than the fullerene-like I(h) cage isomer at the B3LYP/cc-pVDZ level of theory. Introducing endo Ge-H bonds increases the stability of both cage and tube isomers. The most stable tube isomer can admit six endo Ge-H bonds. The cage isomer can admit 10-12 endo Ge-H bonds (H(10)@Ge(60)H(50) and H(12)@Ge(60)H(48)), and they also represent the most stable Ge(60)H(60) isomers. The stability order and structural patterns of Ge(60)H(60) are the same as those found for the corresponding Si(60)H(60) isomers. Moreover, it is found that the 6-31G(d,p) basis set fails to predict the relative energies of the Ge(60)H(60) isomers and the Ge(6)H(6) isomers.

The ground- and excited-state structures of five Re(I) halide glyoxime complexes ReCl(CO)(3)(N(∧)N) (N(∧)N = glyoxime (DHG 1), dimethylglyoxime (DMG 2), cyclohexane dione glyoxime (CHDG 3), dibromoglyoxime (DBG 4), and dimethylformylgloxime (DMFG 5)) have been studied with density functional theory (DFT) and configuration interaction with single excitations (CIS) methods. Time-dependent density functional theory/polarized continuum model (TDDFT/PCM) was carried out to predict the absorption and emission spectra in different media. The effect of substituent and solvent has been researched. It is found that electron-donating groups increase the lowest unoccupied molecular orbital (LUMO) energy resulting in the increased highest occupied molecular orbital (HOMO)-LUMO energy gap. The change leads to their absorption spectra blue shifts in the order 1 > 2 > 3, which arises from the HOMO-1 → LUMO. Just the opposite, electron-withdrawing groups lead to the spectra red shifts (5 > 4 > 1) because of the decreased HOMO-LUMO energy gap. The reorganization energy (λ) calculations show that the relatively balanceable charges transfer abilities of 2 will result in the higher efficiency of organic light emitting devices (OLEDs). In addition, both the absorption and the emission spectra display red shifts in different extents with the decrease of solvent polarity.

The mechanistic details of the coupling reaction of propylene oxide with carbon dioxide catalyzed by copper(I) cyanomethyl to yield cyclic carbonate were elucidated by density functional theory (DFT) calculations at the B3LYP/6-311G** level. Our results reveal that the overall reaction is stepwise and considered to include two processes. In process 1, CO(2) insertion into the Cu(I)-C bond of copper(I) cyanomethyl affords activated carbon dioxide carriers. In process 2, O-coordination of propylene oxide molecule to the electrophilic copper center of carriers occurs. Herein, three possible pathways were investigated, and the calculated reaction free energy profiles were compared. It was found that carrier 8 reacting with propylene oxide is more favored than the other two carriers (6 and 7) both kinetically and thermodynamically. Several factors, such as the composition of catalyst, the coordinate environment of copper, and the symmetry of frontier molecular orbitals, affected the reaction mechanisms, and the outcomes were identified. The overall reaction is exothermic. In addition, natural bond orbital (NBO) analysis has been performed to study the effects of charge transfer and understand the nature of different interactions between atoms and groups. The present theoretical study explains satisfactorily the early reported experimental observations well and provides a clear profile for the cycloaddition of carbon dioxide with propylene oxide promoted by NCCH(2)Cu.

Solvothermal treatment of a mixture of Co(OAc)(2), NaN(3), NaN(CN)(2), HF, MeCN, and H(2)O generated an AlB(2)-like metal-organic framework, namely, [{(Co(3)F)(3)(trta)(2)(H(2)O)(9)}{Co(Hbta)(3)}(2)].11H(2)O (1) (H(3)trta = N,N,N-tris-tetrazol-5-yl-amine; H(3)bta = N,N-bis-tetrazol-5-yl-amine), in which supertrianglar supramolecular building blocks (SBBs) {(Co(3)F)(3)(trta)(2)} act as 12-connected nodes of hexagonal prisms. The unprecedented ligand N,N,N-tris-tetrazol-5-yl-amine is in situ generated via metal-assisted reactions of NaN(CN)(2), MeCN, and NaN(3), and a possible mechanism involves both 1,3-dipolar cycloaddition and nucleophilic addition. The F-centered Co(3) triangles are bridged by trta groups to result in supertriangular {(Co(3)F)(3)(trta)(2)} SBBs that are further arranged in a frustrated triangular lattice. The long-range ordering temperature is reduced to 4.8 K due to strong spin frustration.

Hydrothermal reaction of Cu(MeCO2)2, (4-pyridylthio)acetic acid and NH4SCN resulted in a twelve-connected face-centered cubic topological metal-organic framework [Cu3(pdt)2(CN)] (pdt = pyridinethiolate) in which Cu6S4 clusters act as twelve-connected nodes and pyridine rings and cyanides act as connectors. As an extension, an unprecedented fourteen-connected body-centered cubic coordination polymer [Cu19I4(pdt)12(SH)3] has been synthesized by three methods, in which nanosized chiral Cu19I4S12 clusters act as fourteen-connected nodes and triple pyridine rings and hydrosulfides act as connectors. The in situ S-C(sp(3)), S-C(sp(2)), and S-C(sp) cleavage reactions have been observed in the work.

A hybrid material constructed of 3/19 site-modified Brucite-like cobalt hydroxide and cobalt-oxalate, two types of new layered structural motifs, has been synthesized that shows rare 3D Co-O-Co connectivity and ferrimagnetic ordering.

Tube C(60)H(60) (5) with fused five-membered rings is more stable than the cage isomer (1) with isolated five-membered rings. Introduction of endo C-H bonds into structure 5 results in further stabilization, but the most stable tube structure with four endo C-H bonds (7) is higher in energy than the most stable cage structure with ten endo C-H bonds (3) by 74.2 kcal/mol. A comprehensive comparison of C(60)H(60) with C(60)F(60) has been made.

Hydrothermal reactions generated two cuprous cyanide polymorphs with similar hexagonal [Cu2(CN)3](-) layers but different supramolecular arrays.

The structure and stability of a set of (CF)60 isomers have been computed at the B3LYP/6-31G(d) density functional theory level. The most stable isomer (6, F4@C60F56) has tube-like structure with four endo C-F bonds and fused five-membered rings at the end of the tube, while the reported most stable cage structure (2, F8@C60F52) with eight endo C-F bonds is higher in energy by 22.6 kcal/mol. This is in contrast to the isolated pentagon rule for the stability of fullerenes. The mean bond dissociation energy of 6 is larger than those of the experimental known C60F36, C60F48, and graphite fluoride. The relative energy per CF unit of 6 to graphite fluoride (CF)n is 3.7 kcal/mol, which is smaller than that of C60 fullerene per carbon to graphite (about 9-10 kcal/mol).

The complex doublet potential surface of the NCO + HCNO reaction has been investigated at the QCISD(T)/6-311g(d,p)//UB3LYP/6-31G(d,p) level. We have found 29 isomers on the potential surface, which are connected by 38 transition states. The single-point energy calculations are performed at the high-level QCISD(T)/6-311G(d,p) for more accurate energy values. In various possible initial association ways, the end-N attack leading to HC2N2O2 a1 and a2 is the most favorable association way through a barrierless process. Through the thermodynamic and kinetic analyses, the product NO + CO + HCN should be the major product in both the low- and high-temperature conditions for its low-energy determination transition state. Our calculation is consistent with the available data in low-temperature condition and expected to be confirmed in the high-temperature condition.

Density functional theory calculations have been carried out to investigate 12-electron reduced alpha, beta, gamma, delta, and epsilon Keggin-like [(MoO4)Mo12O12S12(OH)12]2- polyoxothiometalates (POTMs), which show that the stability order is alpha < beta < gamma < delta < epsilon that is perfectly inverse to the well-known trend of the classical Keggin polyoxometalates. Energy decomposition analysis reveals that the enhanced stabilities of gamma, delta, and epsilon isomers originate the favorable arrangements of their Mo12O12S12(OH)12 shell, in which the edge-sharing [MoV2(mu-S)2O2] fragment plays a fundamental role in stabilizing the overall structure. Both frontier orbital analysis and Mayer indexes exhibit that a Mo-Mo single bond is formed inside the [MoV2(mu-S)2O2] fragment, which leads to the localization of the two reduced electrons. As compared with experimentally discovered cyclic [(C9H3O6)@Mo12O12S12(OH)12]3-, all Keggin POTM structures are less stable due to their disfavored cage framework and the disadvantageous host-guest interaction. However, the epsilon-type Keggin POTM that has the largest similarity to the cyclic species is possibly available in the presence of appropriate templates.

Density functional theory calculations have been carried out to investigate the electronic structures and the alpha/beta relative stability of Keggin-typed [XW(12)O(40)]n- anions with transition metal as heteroatom X (X = Cr(VI), V(V), Ti(IV), Fe(III), Co(III), Ni(III), Co(II) and Zn(II)). Nice agreement in geometries between computation and experiment has been obtained, and the higher stability of the alpha isomer over the beta one has been confirmed. Structural parameter analysis reveals that the {M(3)O(13)} triads in both alpha and beta isomers contract considerably with the increase of the negative anionic charge, while the overall size of both isomers shrinks only slightly. Fragment molecular orbital analysis shows that except alpha/beta-[TiW(12)O(40)]4-, the electronic structures of Keggin anions can be described by the insertion of the e and/or t2 orbital of XO4n- into the frontier orbitals of W(12)O(36) cage, and this leads to the specific redox property, which is different from that of the Keggin anions with main-group elements as heteroatoms. Energy decomposition analysis shows that the enhanced intrinsic stability of the alpha isomer in Td arrangement of W(12)O(36) shell and the larger deformation of the alpha over the beta isomer are two dominating factors and contribute oppositely to the alpha/beta relative stability.

The cocrystallization of [Cu(SCN)]n chains and [Cu2(4,4'-bpy)(CN)2]n (4,4'-bpy = 4,4'-bipyridine) layers generated a 3-D pseudopolyrotaxane compound, [Cu2(4,4'-bpy)(CN)2].[Cu(SCN)] (1), which can also be viewed as a 3-D network constructed by linkages of 2-D sheets and 1-D chains via unsupported CuI-CuI interactions. The CuI-CuI contact of 2.651(4) A in 1 is the shortest unsupported CuI-CuI distance documented to date, indicating cuprophilic attractions.

Hydrothermal reaction of Cu(MeCO2)2, (4-pyridylthio)acetic acid, and NH4SCN resulted in a metal-organic framework [Cu3(4-pyridinethiolate)2(CN)] which has twelve-connected face-centered cubic topology with Cu6S4 clusters as nodes.

The structures and energies of isolobal (CH)n and (BCO)n polyhedral species, computed at the B3LYP density functional theory level, reveal contrasts in behavior. The strain energies of the (BCO)n cages are much smaller. Also unlike the (CH)n cages, the most stable (BCO)n polyhedra (n > or = 10) prefer structures with the largest number of three-membered rings. The planar (or nearly planar) faces of the cage systems were modeled by computations on planar, isoelectronic (CH2)n (Dnh) and (HBCO)n (Cnv) rings. While the strain energies of all the planar carbon rings, relative to the most stable D5h (CH2)5, were large, the strain energies of all the planar (HBCO)n (Cnv) rings were small. Remarkably, the three-membered (HBCO)3 (C3v) ring was the most stable. Finally, large (BCO)n systems prefer tubelike rather than cage structures.

Isolobal substitution of CH units by boron carbonyl groups (BCO) at C2,6 and C2,8,4,6 in semibullvalene favors the delocalized neutral bishomoaromatic systems substantially. The homoaromaticity is documented by the computed diatropic nucleus independent chemical shifts (NICS). In addition, BCO substitution can result in low-lying triplet and open-shell singlet states. In contrast, substitution at C1,5 more than doubles the related Cope rearrangement barrier. The C2,6 and C2,8,4,6 BCO-substituted barbaralanes, barbaralones, and bullvalenes have substantially reduced barriers.

Monocyclic boron carbonyls, (BCO)nm, with 4n + 2 delocalized electrons are highly aromatic, as indicated by the computed nucleus independent chemical shift (NICS) and the computed energies for benzene analogue.

A set of novel oligomeric polycyclic neutral oxocarbons has been computed at the B3LYP level of density functional theory. On the basis of the calculated dissociation enthalpies, the most stable structures are C(9)O(9) and C(12)O(12) with benzene-like central ring, in agreement with the experimental finding, and the enhanced stability is due to their aromaticity. Several other oxocarbons also have been identified as stable and are targets for further experimental investigations.