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A series of ten uranium(III) complexes with cyclopentadienyl and monodentate phosphine ligands [UCp3(PR3)] with R=Me, Et, nPr, iPr, tBu, Ph, Cy, F and CF3 was investigated using density functional theory calculations. The ligand dissociation energies were calculated, as well as bonding analysis of the uranium‐phosphorus bond performed, using molecular orbitals, bond orders, quantum theory of atom in molecules (QTAIM) analysis and energy decomposition analysis with natural orbitals for chemical valence (EDA‐NOCV). It was found that the bond orders correlate well with the U−P bond lengths and phosphine cone angles, indicating a large influence of phosphine sterics on the bond properties. All bonding analyses show partial covalent character of the U−P bond, which is most pronounced for PF3 and least for PtBu3. π‐Backbonding was found for the most π‐acidic phosphine ligands. No good correlation was found between the ligand dissociation energies and bond metrics. [ABSTRACT FROM AUTHOR]

Nickel carbenes are key reactive intermediates in the catalytic cyclopropanation of olefins and other reactions, but isolated examples are scarce and generally rely on low coordination numbers (≤3) to stabilize the metal−ligand multiple bond. Here we report the isolation and characterization of a stable tetracoordinated nickel carbene bearing a triphosphine pincer ligand. Its nucleophilic character is evidenced by reaction with acids, and it can transfer the carbene fragment to CO to form a ketene. A computational study of the Ni=C chemical bond sheds light on the role of the third phosphine in the pincer framework to the stabilization of the nickel carbene fragment. [ABSTRACT FROM AUTHOR]

Establishing unprecedented types of bonding interactions is one of the fundamental challenges in synthetic chemistry, paving the way to new (electronic) structures, physicochemical properties, and reactivity. In this context, unsupported element‐element interactions are particularly noteworthy since they offer pristine scientific information about the newly identified structural motif. Here we report the synthesis, isolation, and full characterization of the heterobimetallic Bi/Pt compound [Pt(PCy3)2(BiMe2)(SbF6)] (1), bearing the first unsupported transition metal→bismuth donor/acceptor interaction as its key structural motif. 1 is surprisingly robust, its electronic spectra are interpreted in a fully relativistic approach, and it reveals an unprecedented reactivity towards H2. [ABSTRACT FROM AUTHOR]

Establishing unprecedented types of bonding interactions is one of the fundamental challenges in synthetic chemistry, paving the way to new (electronic) structures, physicochemical properties, and reactivity. In this context, unsupported element‐element interactions are particularly noteworthy since they offer pristine scientific information about the newly identified structural motif. Here we report the synthesis, isolation, and full characterization of the heterobimetallic Bi/Pt compound [Pt(PCy3)2(BiMe2)(SbF6)] (1), bearing the first unsupported transition metal→bismuth donor/acceptor interaction as its key structural motif. 1 is surprisingly robust, its electronic spectra are interpreted in a fully relativistic approach, and it reveals an unprecedented reactivity towards H2. [ABSTRACT FROM AUTHOR]

Establishing unprecedented types of bonding interactions is one of the fundamental challenges in synthetic chemistry, paving the way to new (electronic) structures, physicochemical properties, and reactivity. In this context, unsupported element‐element interactions are particularly noteworthy since they offer pristine scientific information about the newly identified structural motif. Here we report the synthesis, isolation, and full characterization of the heterobimetallic Bi/Pt compound [Pt(PCy3)2(BiMe2)(SbF6)] (1), bearing the first unsupported transition metal→bismuth donor/acceptor interaction as its key structural motif. 1 is surprisingly robust, its electronic spectra are interpreted in a fully relativistic approach, and it reveals an unprecedented reactivity towards H2. [ABSTRACT FROM AUTHOR]

Establishing unprecedented types of bonding interactions is one of the fundamental challenges in synthetic chemistry, paving the way to new (electronic) structures, physicochemical properties, and reactivity. In this context, unsupported element‐element interactions are particularly noteworthy since they offer pristine scientific information about the newly identified structural motif. Here we report the synthesis, isolation, and full characterization of the heterobimetallic Bi/Pt compound [Pt(PCy3)2(BiMe2)(SbF6)] (1), bearing the first unsupported transition metal→bismuth donor/acceptor interaction as its key structural motif. 1 is surprisingly robust, its electronic spectra are interpreted in a fully relativistic approach, and it reveals an unprecedented reactivity towards H2. [ABSTRACT FROM AUTHOR]

Quantum chemical calculations using ab initio methods at the MRCI+Q(8,9)/def2‐QZVPPD and CCSD(T)/def2‐QZVPPD levels as well as using density functional theory are reported for the diatomic molecules AeN− (Ae=Ca, Sr, Ba). The anions CaN− and SrN− have electronic triplet (3Π) ground states with nearly identical bond dissociation energies De ~57 kcal/mol calculated at the MRCI+Q(8,9)/def2‐QZVPPD level. In contrast, the heavier homologue BaN− has a singlet (1Σ+) ground state, which is only 1.1 kcal/mol below the triplet (3Σ−) state. The computed bond dissociation energy of (1Σ+) BaN− is 68.4 kcal/mol. The calculations at the CCSD(T)‐full/def2‐QZVPPD and BP86‐D3(BJ)/def2‐QZVPPD levels are in reasonable agreement with the MRCI+Q(8,9)/def2‐QZVPPD data, except for the singlet (1Σ+) state, which has a large multireference character. The calculated atomic partial charges given by the CM5, Voronoi and Hirshfeld methods suggest small to medium‐sized Ae←N− charge donation for most electronic states. In contrast, the NBO method predicts for all species medium to large Ae→N− electronic charge donation, which is due to the neglect of the (n)p AOs of Ae atoms as genuine valence orbitals. Neither the bond orders nor the bond lengths correlate with the bond dissociation energies. The EDA−NOCV calculations show that the heavier alkaline earth atoms Ca, Sr, Ba use their (n)s and (n‐1)d orbitals for covalent bonding. [ABSTRACT FROM AUTHOR]

While π‐complexes of C=C bonds are ubiquitous in organometallic chemistry, analogous complexes of the isoelectronic but strongly polarized B=N double bond of aminoboranes are extremely scarce. To address this gap, a diphosphine‐aminoborane ligand (PhDPBAiPr) is introduced and its coordination with group 10 metals is investigated. The B=N bond does not coordinate to the metal in Pt(0) and Pd(II) complexes. In contrast, side‐on coordination of the B=N bond is observed in the Ni(0) complex (PhDPBAiPr)Ni(NCPh), and the X‐ray crystal structure reveals B−N bond elongation compared to the free ligand. The choice of co‐ligand strongly influences the presence or absence of side‐on coordination at Ni(0) as evidenced by NMR spectroscopy. While the B=N π‐complex is geometrically similar to C=C analogues, a bonding analysis reveals that the interaction of the B=N motif with the electron‐rich Ni(0) center is best described as 3c4e hyperbond, in which Ni and N are competing for the empty orbital on B. [ABSTRACT FROM AUTHOR]

Metal (iso)cyanides dominate the molecular inventory of metal-bearing species in the interstellar medium. Their oxide counterparts, metal (iso)cyanates, have potential as interstellar molecules and have received significant attention. However, cationic complexes HNCOM+ as precursors to metal (iso)cyanates are rarely studied. Herein, we investigated HNCOCa+ by exploiting infrared spectrometry with isotopic substitutions and quantum chemical calculations. For comparison, the light and heavy alkaline earth metal cationic complexes HNCOBe+ and HNCOBa+ were also explored. HNCOCa+ and HNCOBe+ rather than HNCOBa+ can be experimentally generated by the reactions of metal cations with HNCO. The observed antisymmetric and symmetric NCO stretching vibrations in HNCOCa+ (2362.6 and 1330.4 cm−1) are higher than those in free HNCO (2268.5 and 1320.3 cm−1) but lower than those in HNCOBe+ (2426.4 and 1355.2 cm−1). These shifts can be explained by the charge polarization within the NCO fragment in HNCOBe+ and HN-COCa+. Bonding analysis suggests that HNCO–Be+ bond favors covalent character (54%) while HNCO–Ca+ bond has higher electrostatic character (57%). The dominant electrostatic interaction (64%) in HNCO–Ba+ bond results in the low bond energy, which might account for its absence in experiments. [ABSTRACT FROM AUTHOR]

Structural stability, local density of states, bonding information, and charge distribution differences of C‐substituted ZnO (C/VZnxOy) monolayer structures, as well as their interactions with lithium atoms, are investigated using the density functional theory (DFT) method. The energy required to generate vacancies in pristine ZnO monolayers is considerably high, but since the C atoms are strongly adsorbed in the vacant sites, the energy required to form C/VZnxOy structures is reduced. These lattice substitutions cause an alteration of the Zn d‐states. The bonding analysis shows that the C−O interaction is stronger than the C−Zn interaction. So, it generates high stability for these structures. Furthermore, because the development of C/VZnxOy is aimed at lithium battery electrode applications, the most fundamental thing that needs to be examined initially is the interaction between the C/VZnxOy surfaces and the lithium atoms. Li3 strongly binds on all C/VZnxOy surfaces, and it turns to Li3+ based on a simple analysis of charge distribution differences. These findings will have a substantial impact on the future development of ZnO monolayers, and their potential as lithium battery electrodes can be studied further. [ABSTRACT FROM AUTHOR]

Dynamic bonds are essential structural ingredients of dynamic covalent chemistry that involve reversible cleavage and formation of bonds. Herein, we explore the electronic characteristics of Se−N bonds in the organo‐selenium antioxidant ebselen and its derivatives for their propensity to function as dynamic covalent bonds by employing high‐resolution X‐ray quantum crystallography and complementary computational studies. An analysis of the experimentally reconstructed X‐ray wavefunctions reveals the salient electronic features of the Se−N bonds with very low electron density localized at the bonding region and a positive Laplacian value at the bond critical point. Bond orders and percentage covalency and ionicity estimated from the X‐ray wavefunctions, along with localized orbital locator (LOL) and electron localization function (ELF) analyses show that the Se−N bond is unique in its closed shell‐like features, despite being a covalent bond. Time‐dependent DFT calculations simulate the cleavage of Se−N bonds in ebselen in the excited state, further substantiating their nature as dynamic bonds. [ABSTRACT FROM AUTHOR]

Chemical bonding is one of the core concepts in the whole field of chemistry and provides a very effective way of communication. It must be clear that chemical bonds are not real, they are artificially abstracted concepts. To accurately describe chemical bonding, various models or theories have been proposed throughout history. The most widely used models are the electron-pair bonding model and hybrid orbital theory. However, the rules of thumb have their limitations, as evident in the explanation of hypervalent molecules. We suggest that in teaching, hypervalent molecules should be used as examples to explicitly point out the shortcomings of empirical rules in describing chemical bonding to younger students. In another hand, molecular orbital theory or modern valence bond theory can be used on bonding analysis for senior students. It is expected that students maintain an open-minded attitude towards the behavior of chemical bonding and cultivate spirit of scientific inquiry. [ABSTRACT FROM AUTHOR]

Bismuth polycations have garnered significant attention from researchers due to their extraordinary and counter‐intuitive structures and stoichiometries. Despite extensive experimental and theoretical investigations, understanding of the bonding in such clusters remains insufficient. An AdNDP bonding analysis was conducted to elucidate the bonding characteristics using both homoatomic and heteroatomic bismuth clusters with various stoichiometries. Analysis of the calculated nucleus‐independent chemical shift data confirmed the aromatic nature of these species. Universal bonding patterns were identified that can be applied to a range of homoatomic and heteroatomic bismuth clusters. Additionally, calculations of absorbance and fluorescence spectra were performed to gain insights into the near‐infrared emission and establish a potential correlation between absorbance and the identified bonding patterns. [ABSTRACT FROM AUTHOR]

The symmetry‐decomposed Voronoi deformation density (VDD) charge analysis is an insightful and robust computational tool to aid the understanding of chemical bonding throughout all fields of chemistry. This method quantifies the atomic charge flow associated with chemical‐bond formation and enables decomposition of this charge flow into contributions of (1) orbital interaction types, that is, Pauli repulsive or bonding orbital interactions; (2) per irreducible representation (irrep) of any point‐group symmetry of interacting closed‐shell molecular fragments; and now also (3) interacting open‐shell (i.e., radical) molecular fragments. The symmetry‐decomposed VDD charge analysis augments the symmetry‐decomposed energy decomposition analysis (EDA) so that the charge flow associated with Pauli repulsion and orbital interactions can be quantified both per atom and per irrep, for example, for σ, π, and δ electrons. This provides detailed insights into fundamental aspects of chemical bonding that are not accessible from EDA. [ABSTRACT FROM AUTHOR]

To understand the interfacial bond formation between polycarbonate (PC) and magnetron‐sputtered metal nitride thin films, PC | X interfaces (X = AlN, TiN, (Ti,Al)N) are comparatively investigated by ab initio simulations as well as X‐ray photoelectron spectroscopy. The simulations predict significant differences at the interface as N and Ti form bonds with all functional groups of the polymer, while Al reacts selectively only with the carbonate group of pristine PC. In good agreement with simulations, experimental data reveal that the PC | AlN and the PC | (Ti,Al)N interfaces are mainly defined by interfacial C─N bonds, whereas for PC | TiN, the interface formation is also characterized by numerous C─Ti and (C─O)─Ti bonds. Bond strength calculations combined with the measured interfacial bond density indicate the strongest interface for PC | (Ti,Al)N followed by PC | AlN, whereas the weakest is predicted for PC | TiN due to its lower density of strong interfacial C─N bonds. This study shows that the employed computational strategy enables prediction of the interfacial bond formation between PC and metal nitrides and that it is reasonable to assume that the research strategy proposed herein can be readily adapted to other organic | inorganic interfaces. [ABSTRACT FROM AUTHOR]

The reported tetracoordinate dilithio methandiide complex from Liddle and co‐workers (1) is investigated from a coordination chemistry perspective, to probe the origin of its intriguing geometry. Through the application of a variety of computational techniques, non‐covalent (steric, electrostatic) interactions are found to be dominant. Further, we arrive at a bonding description which emphasizes the tricoordinate sp2‐hybridized nature of the central methandiide carbon, differing somewhat from the original proposal. Thus, 1 is distinct from other dilithio methandiides since it contains only one C−Li σ‐bond, and is found to be comparable to a simple aryllithium compound, phenyllithium. [ABSTRACT FROM AUTHOR]

Quantum chemical calculations have been carried out at the BP86/def2‐SVP level on Ge8(Sit‐butyl2methyl)6 (1) and the bonding situation has been analyzed with a variety of methods. The calculated equilibrium geometry of 1 is in good agreement with the reported x‐ray structure analysis. The D3 correction for dispersion interactions as a sum of pairwise attractions leads to an overestimate of the effect of dispersion forces. Calculations at BP86‐D3(BJ)/def2‐SVP give shorter bonds for Ge(I)−Ge(I) than for Ge(0)−Ge(I), which is in contrast to the experimental values and the BP86/def2‐SVP results. The NBO analysis suggests that the best Lewis structure of 1 has lone‐pair orbitals at the Ge(0) atoms with occupation numbers of 1.70 e. A lone‐pair character at Ge(0) albeit with less weight is also suggested by the shape of the HOMO, which is an antibonding orbital between the Ge(0) atoms with small contributions from the Ge(I) atoms. The LUMO of 1 is the corresponding bonding combination of the Ge(0) AOs, which can be explained with the reluctance of the heavier main‐group atoms to s/p hybridization of the valence orbitals. The calculated bond order values suggest significant direct Ge(0)−Ge(0) interactions. This is supported by the shape of the HOMO and by the results of EDA‐NOCV calculations. The deformation densities and the orbitals associated with the pairwise orbital interaction show that there is a direct charge flow between the Ge(0) atoms of the two fragments, but it is not completely separated from the Ge(0)−Ge(I) and Ge(I)−Ge(I) bond formation. The QTAIM calculations suggest that 1 has a cubic structure with a cage critical point but not a bond critical point for the Ge(0)−Ge(0) interactions. The dispersion interactions of the large substituents in 1 have a significant influence on the stability of the compound. [ABSTRACT FROM AUTHOR]

Quantum chemical calculations have been carried out at the BP86/def2‐SVP level on Ge8(Sit‐butyl2methyl)6 (1) and the bonding situation has been analyzed with a variety of methods. The calculated equilibrium geometry of 1 is in good agreement with the reported x‐ray structure analysis. The D3 correction for dispersion interactions as a sum of pairwise attractions leads to an overestimate of the effect of dispersion forces. Calculations at BP86‐D3(BJ)/def2‐SVP give shorter bonds for Ge(I)−Ge(I) than for Ge(0)−Ge(I), which is in contrast to the experimental values and the BP86/def2‐SVP results. The NBO analysis suggests that the best Lewis structure of 1 has lone‐pair orbitals at the Ge(0) atoms with occupation numbers of 1.70 e. A lone‐pair character at Ge(0) albeit with less weight is also suggested by the shape of the HOMO, which is an antibonding orbital between the Ge(0) atoms with small contributions from the Ge(I) atoms. The LUMO of 1 is the corresponding bonding combination of the Ge(0) AOs, which can be explained with the reluctance of the heavier main‐group atoms to s/p hybridization of the valence orbitals. The calculated bond order values suggest significant direct Ge(0)−Ge(0) interactions. This is supported by the shape of the HOMO and by the results of EDA‐NOCV calculations. The deformation densities and the orbitals associated with the pairwise orbital interaction show that there is a direct charge flow between the Ge(0) atoms of the two fragments, but it is not completely separated from the Ge(0)−Ge(I) and Ge(I)−Ge(I) bond formation. The QTAIM calculations suggest that 1 has a cubic structure with a cage critical point but not a bond critical point for the Ge(0)−Ge(0) interactions. The dispersion interactions of the large substituents in 1 have a significant influence on the stability of the compound. [ABSTRACT FROM AUTHOR]

Abstract To understand the interfacial bond formation between polycarbonate (PC) and magnetron‐sputtered metal nitride thin films, PC | X interfaces (X = AlN, TiN, (Ti,Al)N) are comparatively investigated by ab initio simulations as well as X‐ray photoelectron spectroscopy. The simulations predict significant differences at the interface as N and Ti form bonds with all functional groups of the polymer, while Al reacts selectively only with the carbonate group of pristine PC. In good agreement with simulations, experimental data reveal that the PC | AlN and the PC | (Ti,Al)N interfaces are mainly defined by interfacial C─N bonds, whereas for PC | TiN, the interface formation is also characterized by numerous C─Ti and (C─O)─Ti bonds. Bond strength calculations combined with the measured interfacial bond density indicate the strongest interface for PC | (Ti,Al)N followed by PC | AlN, whereas the weakest is predicted for PC | TiN due to its lower density of strong interfacial C─N bonds. This study shows that the employed computational strategy enables prediction of the interfacial bond formation between PC and metal nitrides and that it is reasonable to assume that the research strategy proposed herein can be readily adapted to other organic | inorganic interfaces.

Nanocrystalline Selenium was synthesized within a silica matrix using a sol-gel method with high-purity SeO2, ethyl alcohol, distilled water, and TEOS (Tetraethyl orthosilicate). This process encapsulated the selenium dioxide in the silica matrix, which was then reduced at about 100°C using an oil bath. Three reducing agents were employed: acetone vapor, and sodium borohydride (NaBH4) and hydrazine (N2H4) in liquid form. DSC-TGA analyses of the precursor mixture determined the crystallization temperature for selenium nanoparticle formation within the matrix to be around 100°C. Post-heating phase analysis via XRD revealed hexagonal structures, with crystallite sizes between 33 and 43 nm determined using Debye-Scherrer's formula. Morphological studies showed irregular polygonal shapes with rough surfaces, with particulate sizes under 0.2μ for acetone vapor, around 0.1μ for hydrazine, and slightly over 0.1μ for sodium borohydride. Time variations were explored to observe phase and crystallite size changes. FTIR analysis was conducted for bonding assessment, revealing M-O coordination. The composite's absorbance was examined through UV-VIS spectroscopy, and its morphological attributes were investigated using FESEM analysis, complemented by EDX to determine elemental composition. [ABSTRACT FROM AUTHOR]

The title silver(I) complex salts [Ag{Re2(CO)10}{Re(CO)5}2]+[Al(ORF)4]− (AgRe4; ORF=‐OC(CF3)3) and [Ag{Ir4(CO)12}2]+[Al(ORF)4]− (AgIr8) form upon reaction of Ag+[Al(ORF)4]− and the transition metal carbonyls (TMCs) Re2(CO)10 and Ir4(CO)12 respectively. The solid‐state structure of the AgRe4 cluster shows an unexpected asymmetric coordination motif, wherein the silver(I) cation has inserted into the Re−Re bond of one Re2(CO)10 moiety, while the other dirhenium carbonyl coordinates only over one metal atom towards the silver(I) cation. The AgIr8 cluster is formed by the edge‐on coordination of two Ir4 tetrahedra and the silver cation in a D2 symmetric fashion with a torsion angle of 46.5°. QTAIM analysis shows bond paths between the silver atom and the nearby metal atoms in all cases, whereas only the non‐inserted Re2(CO)10 moiety shows additional bond paths between the carbonyl ligands and the silver cation. In addition, the insertion of the Ag+ cation into the Re−Re bond in Re2(CO)10 removes the bond path between the two rhenium atoms. The EDA‐NOCV analysis suggests an increase of the interaction energy between the silver(I) cation and the respective metal carbonyls from the metal centered transition metal carbonyl (TMC) donors W(CO)6

Quantum chemical calculations using ab initio methods at the MRCI+Q(6,8)/def2‐QZVPP and CCSD(T)/def2‐QZVPP levels as well as density functional theory are reported for the diatomic molecules AeB− and isoelectronic AeC (Ae=Ca, Sr, Ba). The boride anions AeB− have an electronic triplet (3Σ−) ground state. The quintet (5Σ−) state is 5.8–12.3 kcal/mol higher in energy and the singlet (1Δ) state is 13.1–15.3 kcal/mol above the triplet. The isoelectronic AeC molecules are also predicted to have a low‐lying triplet (3Σ−) state but the quintet (5Σ−) state is only 2.2 kcal/mol (SrC) and 2.9 kcal/mol (CaC) above the triplet state. The triplet (3Σ−) and quintet (5Σ−) states of BaC are nearly isoenergetic. All systems have rather strong bonds. The calculated bond dissociation energies of the triplet (3Σ−) state are between De=38.3–41.7 kcal/mol for AeB− and De=49.4–57.5 kcal/mol for AeC. The barium species have always the strongest bonds whereas the calcium and strontium compounds have similar BDEs. The bonding analysis indicates that there is little charge migration in AeB− in the direction Ae→B− where the alkaline earth atoms carry positive charges between 0.09 e–0.22 e. The positive charges at the Ae atoms are much larger in AeC where the charge migration Ae→C is between 0.90 e–0.91 e. A detailed analysis of the interatomic interactions with the EDA‐NOCV method shows that all diatomic species AeB− and AeC are built from dative interactions between Ae (1S, ns2) and B− or C (3P, 2 s22pπ12pπ′1). The eventually formed bonds in AeC are better described in terms of interactions between the ions Ae+ (2S, ns1)+C− (4S, 2 s22pπ12pπ′12pσ1). Inspection of the orbital interactions suggests that the alkaline earth atoms Ca, Sr, Ba use mainly their (n‐1)d AOs besides the (n)s AOs for the covalent bonds. This creates a second energetically low‐lying σ‐bonding MO in the molecules, which feature valence orbitals with the order ϕ1 (σ‐bonding)<ϕ2 (σ‐bonding)<ϕ3 (degenerate π‐bonding). All four occupied valence MOs of AeB− and AeC are bonding orbitals. Since the degenerate π orbitals ϕ3 are only singly occupied, the formal bond order is three. [ABSTRACT FROM AUTHOR]

Context: Just how much effort and detail should we invest in analyzing interactions of the order of 5 kcal mol−1? This comment attempts to provide a conciliatory overview of what is often a contentious field and to pose some questions that I hope will eventually lead at least to some consensus. Methods: This is an opinion article without calculations or data. [ABSTRACT FROM AUTHOR]

The bonding situation in the tricoordinated beryllium phenyl complexes [BePh3]−, [(pyridine)BePh2] and [(trimethylsilyl‐N‐heterocyclic imine)BePh2] is investigated experimentally and computationally. Comparison of the NMR spectroscopic properties of these complexes and of their structural parameters, which were determined by single crystal X‐ray diffraction experiments, indicates the presence of π‐interactions. Topology analysis of the electron density reveals elliptical electron density distributions at the bond critical points and the double bond character of the beryllium‐element bonds is verified by energy decomposition analysis with the combination of natural orbital for chemical valence. The present beryllium‐element bonds are highly polarized and the ligands around the central atom have a strong influence on the degree of π‐delocalization. These results are compared to related triarylboranes. [ABSTRACT FROM AUTHOR]

The classic pnictogen dichotomy stands for the great contrast between triply bonding very stable N2 molecules and its heavier congeners, which appear as dimers or oligomers. A banner example involves phosphorus as it occurs in nature as P4 instead of P2, given its weak π‐bonds or strong σ‐bonds. The P2 synthetic value has brought Lewis bases and metal coordination stabilization strategies. Herein, we discuss the unrealized encapsulation alternative using the well‐known fullerenes' capability to form endohedral and stabilize otherwise unstable molecules. We chose the most stable fullerene structures from Cn (n = 50, 60, 70, 80) and experimentally relevant from Cn (n = 90 and 100) to computationally study the thermodynamics and the geometrical consequences of encapsulating P2 inside the fullerene cages. Given the size differences between P2 and P4, we show that the fullerenes C70–C100 are suitable cages to side exclude P4 and host only one molecule of P2 with an intact triple bond. The thermodynamic analysis indicates that the process is favorable, overcoming the dimerization energy. Additionally, we have evaluated the host‐guest interaction to explain the origins of their stability using energy decomposition analysis. [ABSTRACT FROM AUTHOR]

Understanding crystalline structures based on their chemical bonding is growing in importance. In this context, chemical bonding can be studied with the Crystal Orbital Hamilton Population (COHP), allowing for quantifying interatomic bond strength. Here we present a new set of tools to automate the calculation of COHP and analyze the results. We use the program packages VASP and LOBSTER, and the Python packages atomate and pymatgen. The analysis produced by our tools includes plots, a textual description, and key data in a machine‐readable format. To illustrate those capabilities, we have selected simple test compounds (NaCl, GaN), the oxynitrides BaTaO2N, CaTaO2N, and SrTaO2N, and the thermoelectric material Yb14Mn1Sb11. We show correlations between bond strengths and stabilities in the oxynitrides and the influence of the Mn−Sb bonds on the magnetism in Yb14Mn1Sb11. Our contribution enables high‐throughput bonding analysis and will facilitate the use of bonding information for machine learning studies. [ABSTRACT FROM AUTHOR]

Azo‐based energetic materials may initiate explosive decomposition by extruding molecular nitrogen to produce radical fragments. Density functional theory and Wiberg bond index analysis were used to determine trends in bond strength for a series of aromatic azo compounds. Interactions between ortho ring hydrogens and an azo nitrogen lone pair favor a planar molecule with a strengthened azo linkage. Steric groups substituted ortho to the azo linkage cause the molecule to twist, which disrupts delocalization of the π density and weakens the CNazo bond. The results of this study are generally consistent with the low sensitivity of various aromatic azo‐based energetic materials. Discrepancies between calculated bond strengths and the experimental impact sensitivities could be attributed to packing forces that affect molecular planarity in the solid state. [ABSTRACT FROM AUTHOR]

High-pressure, high-temperature synthesis at 12 GPa between 750 and 1000°C for 30 to 300 min yields the last missing rare-earth metal monogermanide, YbGe. Powder and single-crystal X-ray diffraction measurements reveal that the compound crystallizes in a FeB-type structure (space group Pnma, a = 7.901(2) Å, b = 3.8981(9) Å, and c = 5.873(2) Å). The results of the chemical bonding study, while supporting the presence of polyanionic Ge chains interacting with the surrounding Yb through multi-atomic polar bonds, suggest a transitional scenario between the monogermanides formed by alkaline‑earth metals and those formed by trivalent rare‑earth metals., (© 2025 Wiley‐VCH GmbH.)

The bonding situation in the intermetallic compounds LaBeGe and ThBeGe were investigated using the wavefunctions generated from the all‐electron relativistic density functional calculations. Following the quantum theory of atoms in molecules (QTAIM) the atomic basins were determined from the electron density and the effective charges computed. These were also compared to corresponding charges for the procrystal density. The bonding was analyzed utilizing the delocalization indices (DIs) computed from the overlap integrals over the QTAIM basins. The analysis was extended by the evaluation of the electron localizability indicator (ELI‐D) and completed by the calculation of DIs for the ELI‐D basins. [ABSTRACT FROM AUTHOR]

The structure, stability, and bonding situation of some exemplary noble gas-silicon cations were investigated at the MP2/aVTZ level of theory. The explored species include the mono-coordinated NgSiX3+ (Ng = He-Rn; X = H, F, Cl) and NgSiF22+ (Ng = He-Rn), the di-coordinated Ar2SiX3+ (X = H, F, Cl), and the "inserted" FNgSiF2+ (Ng = Kr, Xe, Rn). The bonding analysis was accomplished by the method that we recently proposed to assay the bonding situation of noblegas compounds. The Ng-Si bonds are generally tight and feature a partial contribution of covalency. In the NgSiX3+, the degree of the Ng-Si interaction mirrors the trends of two factors, namely the polarizability of Ng that increases when going from Ng = He to Ng = Rn, and the Lewis acidity of SiX3+ that decreases in the order SiF3+ > SiH3+ > SiCl3+. For the HeSiX3+, it was also possible to catch peculiar effects referable to the small size of He. When going from the NgSiF3+ to the NgSiF22+, the increased charge on Si promotes an appreciable increase inthe Ng-Si interaction, which becomes truly covalent for the heaviest Ng. The strength of the bond also increases when going from the NgSiF3+ to the "inserted" FNgSiF2+, likely due to the cooperative effect of the adjacent F atom. On the other hand, the ligation of a second Ar atom to ArSiX3+ (X = H, F, Cl), as to form Ar2(SiX3+), produces a weakening of the bond. Our obtained data were compared with previous findings already available in the literature. [ABSTRACT FROM AUTHOR]

Bonding Analysis, the support of pregnant individuals in relation with their child, allows us to access the reality of a primary layer of experience between the pregnant parent and child during the prenatal period and makes it available for reflection. The influence of this primary layer on our experiencing and our actions, both on an individual level and on the level of society and culture, becomes obvious. From these observations we can conclude that prenatal and perinatal dreamlike projections significantly influence sociocultural processes [ABSTRACT FROM AUTHOR]

In this work, a theoretical study for platinum(II)-8-hydroxyquinoline-tetrylene complexes [{PtCl–C9H6NO}–NHEPh] (Pt–EPh) is carried out for the first time by using the density functional theory (DFT). Quantum chemical calculations with DFT and charge methods at the BP86 level with basic sets SVP and TZVPP have been perfomed to get insight into the structures and property of Pt–EPh. The optimization of equilibrium geometries of the ligands EPh in Pt–EPh, bonded in the distorted end-on way to the Pt fragment is studied, in which the bending angle slightly decreases from carbene Pt–CPh to germylene Pt–GePh. Quantum chemical parameters such as EHOMO, ELUMO, the energy gap (ELUMO – EHOMO), electronegativity, global hardness, and global softness in the neutral molecules have been calculated and discussed. Bond dissociation energies decrease from the slighter to the heavier homologues. The hybridization of atoms E has large p characters, while the hybridization of atom Pt has a greater d character. Thus, the Pt–E bond possesses not only NHEPh→{PtCl–C9H6NO} strong -donation but also a significant contribution of π-donation NHEPh→{PtCl–C9H6NO}, and a weak π-backdonation metal-ligand NHEPh←{PtCl-C9H6NO} in complexes Pt-EPh is also considered.

We report a series of isostructural tetravalent actinide (Th, U−Pu) complexes with the N‐donor ligand N,N'‐ethylene‐bis((pyrrole‐2‐yl)methanimine) (H2L, H2pyren). Structural data from SC‐XRD analysis reveal [An(pyren)2] complexes with different An−Nimine versus An−Npyrrolide bond lengths. Quantum chemical calculations elucidated the bonding situation, including differences in the covalent character of the coordinative bonds. A comparison to the intensely studied analogous N,N′‐ethylene‐bis(salicylideneimine) (H2salen)‐based complexes [An(salen)2] displays, on average, almost equal electron sharing of pyren or salen with the AnIV, pointing to a potential ligand‐cage‐driven complex stabilisation. This is shown in the fixed ligand arrangement of pyren and salen in the respective AnIV complexes. The overall bond strength of the pure N‐donor ligand pyren to AnIV (An=Th, U, Np, Pu) is slightly weaker than to salen, with the exception of the PaIV complex, which exhibits extraordinarily high electron sharing of pyren with PaIV. Such an altered ligand preference within the early AnIV series points to a specificity of the 5f1 configuration, which can be explained by polarisation effects of the 5 f electrons, allowing the strongest f electron backbonding from PaIV (5f1) to the N donors of pyren. [ABSTRACT FROM AUTHOR]

Addition of PR3 (R=Ph or OPh) to [Cu(η(2)-Me6C6)2][PF6] results in the formation of [(η(6)-Me6C6)Cu(PR3)][PF6], the first copper-arene complexes to feature an unsupported η(6) arene interaction. A DFT analysis reveals that the preference for the η(6) binding mode is enforced by the steric clash between the methyl groups of the arene ligand and the phenyl rings of the phosphine co-ligand.

Diberyllium complexes with ultrashort metal−metal distances (USMMDs, defined as dM−M<1.900 Å) are fascinating for the nature of the valence electronic structure of Be atoms. In this paper a family of diberyllium complexes [L−BeH3Be−L]+ (1–7), in which L was an N‐heterocyclic carbene (NHC) or a mesoionic carbene (MIC), were studied by Density Functional Theory (DFT) at the B3LYP/cc‐pVTZ level. It was found that complexes 1–7 possessed ultrashort Be−Be distances of 1.754 Å–1.779 Å and strong covalent bonds between a Be atom and its adjacent carbene center (Ccarb) at once. Electronic structures and chemical bonding analyses ascribed USMMDs between the Be atoms to the Be−H−Be three‐center two‐electron (3c‐2e) bonds. The strong Be−Ccarb bonds were determined by combining effects of covalent interaction and electrostatic interaction between the Be and the Ccarb atoms. These complexes exhibited a great stability with large highest occupied molecular orbital‐lowest unoccupied molecular orbital (HOMO‐LUMO) gaps, high vertical detachment energies (VDEs) and low vertical electron affinities (VEAs) and are potential targets in future experiments. [ABSTRACT FROM AUTHOR]

Barium complexes ligated by bulky boryloxides [OBR2]− (where R=CH(SiMe3)2, 2,4,6‐iPr3‐C6H2 or 2,4,6‐(CF3)3‐C6H2), siloxide [OSi(SiMe3)3]−, and/or phenoxide [O‐2,6‐Ph2‐C6H3]−, have been prepared. A diversity of coordination patterns is observed in the solid state for both homoleptic and heteroleptic complexes, with coordination numbers ranging between 2 and 4. The identity of the bridging ligand in heteroleptic dimers [Ba(μ2‐X1)(X2)]2 depends largely on the given pair of ligands X1 and X2. Experimentally, the propensity to fill the bridging position increases according to [OB{CH(SiMe3)2}2)]−<[N(SiMe3)2]−<[OSi(SiMe3)3]−<[O(2,6‐Ph2‐C6H3)]−<[OB(2,4,6‐iPr3‐C6H2)2]−. This trend is the overall expression of 3 properties: steric constraints, electronic density and σ‐ and π‐donating capability of the negatively charged atom, and ability to generate Ba ⋅ ⋅ ⋅ F, Ba ⋅ ⋅ ⋅ C(π) or Ba ⋅ ⋅ ⋅ H−C secondary interactions. The comparison of the structural motifs in the complexes [Ae{μ2‐N(SiMe3)2}(OB{CH(SiMe3)2}2)]2 (Ae = Mg, Ca, Sr and Ba) suggest that these observations may be extended to all alkaline earths. DFT calculations highlight the largely prevailing ionic character of ligand‐Ae bonding in all compounds. The ionic character of the Ae‐ligand bond encourages bridging coordination, whereas the number of bridging ligands is controlled by steric factors. DFT computations also indicate that in [Ba(μ2‐X1)(X2)]2 heteroleptic dimers, ligand predilection for bridging vs. terminal positions is dictated by the ability to establish secondary interactions between the metals and the ligands. [ABSTRACT FROM AUTHOR]

Heteronuclear calcium–iron carbonyl cation complexes in the form of [CaFe(CO)n]+ (n=5–12) are produced in the gas phase. Infrared photodissociation spectroscopy in conjunction with quantum chemical calculations confirm that the n=10 complex is the coordination saturated ion where a Fe(CO)4 fragment is bonded with a Ca(CO)6 fragment through two side‐on bridging carbonyl ligands. Bonding analysis indicates that it is best described by the bonding interactions between a [Ca(CO)6]2+ dication and an [Fe(CO)4]− anion forming a Fe→Ca d−d dative bond in the [(CO)6Ca–Fe(CO)4]+ structure, which enriches the pool of experimentally observed complexes of calcium that mimic transition metal compounds. The molecule is the first example of a heteronuclear carbonyl complex featuring a d−d bond between calcium and a transition metal. [ABSTRACT FROM AUTHOR]

A fundamental and ubiquitous phenomenon in chemistry is the contraction of both C−H and C−C bonds as the carbon atoms involved vary, in s–p hybridization, along sp3 to sp2 to sp. Our quantum chemical bonding analyses based on Kohn–Sham molecular orbital theory show that the generally accepted rationale behind this trend is incorrect. Inspection of the molecular orbitals and their corresponding orbital overlaps reveals that the above‐mentioned shortening in C−H and C−C bonds is not determined by an increasing amount of s‐character at the carbon atom in these bonds. Instead, we establish that this structural trend is caused by a diminishing steric (Pauli) repulsion between substituents around the pertinent carbon atom, as the coordination number decreases along sp3 to sp2 to sp. [ABSTRACT FROM AUTHOR]

The bonding nature between chalcogenides and rare‐earth‐elements is typically described as ionic in the spirit of the Zintl‐Klemm formalism; yet, recent efforts showed that lanthanides also act as d‐metals in transition‐metal‐post‐transition‐metal‐element bonding. Hence, how can we describe the bonding nature between chalcogen and europium atoms, which have frequently acted as electron‐donors like group‐I/II‐elements? To answer this question, we prototypically explored the electronic structure of Eu2CuSe3, which was obtained in considerable yields from solid‐state reactions of the pure elements at 600 °C. The crystal structure of Eu2CuSe3 was determined based on X‐ray diffraction experiments and it is composed of diverse types of linear chains of selenium polyhedra enclosing the copper and europium atoms. These chains are condensed into ∞2 [EuCuSe3] layers, which are separated by additional europium atoms. From analyses of the crystal structure and electronic structure of Eu2CuSe3, it is clear that there are two different europium valence states, whose nature controls if europium acts as an electron‐donor like a group‐I/II‐element or as a d‐metal. [ABSTRACT FROM AUTHOR]

Syntheses of the copper and gold complexes [Cu{Fe(CO)5}2][SbF6] and [Au{Fe(CO)5}2][HOB{3,5-(CF3)2C6H3}3] containing the homoleptic carbonyl cations [M{Fe(CO)5}2]+ (M=Cu, Au) are reported. Structural data of the rare, trimetallic Cu2Fe, Ag2Fe and Au2Fe complexes [Cu{Fe(CO)5}2][SbF6], [Ag{Fe(CO)5}2][SbF6] and [Au{Fe(CO)5}2][HOB{3,5-(CF3)2C6H3}3] are also given. The silver and gold cations [M{Fe(CO)5}2]+ (M=Ag, Au) possess a nearly linear Fe-M-Fe' moiety but the Fe-Cu-Fe' in [Cu{Fe(CO)5}2][SbF6] exhibits a significant bending angle of 1478 due to the strong interaction with the [SbF6]- anion. The Fe(CO)5 ligands adopt a distorted squarepyramidal geometry in the cations [M{Fe(CO)5}2]+, with the basal CO groups inclined towards M. The geometry optimization with DFT methods of the cations [M{Fe(CO)5}2]+ (M= Cu, Ag, Au) gives equilibrium structures with linear Fe-M-Fe' fragments and D2 symmetry for the copper and silver cations and D4d symmetry for the gold cation. There is nearly free rotation of the Fe(CO)5 ligands around the Fe-M-Fe' axis. The calculated bond dissociation energies for the loss of both Fe(CO)5 ligands from the cations [M{Fe(CO)5}2]+ show the order M=Au (De=137.2 kcal mol-1)>Cu (De=109.0 kcal mol-1)>Ag (De=92.4 kcalmol-1). The QTAIM analysis shows bond paths and bond critical points for the M-Fe linkage but not between M and the CO ligands. The EDA-NOCV calculations suggest that the [Fe(CO)5]←M+→[Fe(CO)5] donation is significantly stronger than the [Fe(CO)5]→M+→[Fe(CO)5] backdonation. Inspection of the pairwise orbital interactions identifies four contributions for the charge donation of the Fe(CO)5 ligands into the vacant (n)s and (n)p AOs of M+ and five components for the backdonation from the occupied (n-1)d AOs of M+ into vacant ligand orbitals. [ABSTRACT FROM AUTHOR]

Syntheses of the copper and gold complexes [Cu{Fe(CO)5}2][SbF6] and [Au{Fe(CO)5}2][HOB{3,5-(CF3)2C6H3}3] containing the homoleptic carbonyl cations [M{Fe(CO)5}2]+ (M=Cu, Au) are reported. Structural data of the rare, trimetallic Cu2Fe, Ag2Fe and Au2Fe complexes [Cu{Fe(CO)5}2][SbF6], [Ag{Fe(CO)5}2][SbF6] and [Au{Fe(CO)5}2][HOB{3,5-(CF3)2C6H3}3] are also given. The silver and gold cations [M{Fe(CO)5}2]+ (M=Ag, Au) possess a nearly linear Fe-M-Fe' moiety but the Fe-Cu-Fe' in [Cu{Fe(CO)5}2][SbF6] exhibits a significant bending angle of 1478 due to the strong interaction with the [SbF6]- anion. The Fe(CO)5 ligands adopt a distorted squarepyramidal geometry in the cations [M{Fe(CO)5}2]+, with the basal CO groups inclined towards M. The geometry optimization with DFT methods of the cations [M{Fe(CO)5}2]+ (M= Cu, Ag, Au) gives equilibrium structures with linear Fe-M-Fe' fragments and D2 symmetry for the copper and silver cations and D4d symmetry for the gold cation. There is nearly free rotation of the Fe(CO)5 ligands around the Fe-M-Fe' axis. The calculated bond dissociation energies for the loss of both Fe(CO)5 ligands from the cations [M{Fe(CO)5}2]+ show the order M=Au (De=137.2 kcal mol-1)>Cu (De=109.0 kcal mol-1)>Ag (De=92.4 kcalmol-1). The QTAIM analysis shows bond paths and bond critical points for the M-Fe linkage but not between M and the CO ligands. The EDA-NOCV calculations suggest that the [Fe(CO)5]←M+→[Fe(CO)5] donation is significantly stronger than the [Fe(CO)5]→M+→[Fe(CO)5] backdonation. Inspection of the pairwise orbital interactions identifies four contributions for the charge donation of the Fe(CO)5 ligands into the vacant (n)s and (n)p AOs of M+ and five components for the backdonation from the occupied (n-1)d AOs of M+ into vacant ligand orbitals. [ABSTRACT FROM AUTHOR]

The donor base ligand stabilized compound (L)2C6F4 [1 for L=saturated N‐heterocyclic carbene (SNHCDip) and 2 for L=cyclic alkyl(amino) carbene (cAACMe)] has been investigated by energy decomposition analysis (EDA) coupled with natural orbital for chemical valence (NOCV) calculation. The bonding analysis of 1 has revealed that (SNHCDip)2+ prefers to form an electron sharing σ‐bond, a dative σ‐bond and two dative π‐bonds with the central C6F4− unit in their doublet states. In contrast, (cAACMe)2 forms two electron sharing σ‐bonds and two electron sharing π‐bonds with the neutral C6F4 unit of 2 in their quintet states. [ABSTRACT FROM AUTHOR]

The donor base ligand stabilized compound (L)2C6F4 [1 for L=saturated N‐heterocyclic carbene (SNHCDip) and 2 for L=cyclic alkyl(amino) carbene (cAACMe)] has been investigated by energy decomposition analysis (EDA) coupled with natural orbital for chemical valence (NOCV) calculation. The bonding analysis of 1 has revealed that (SNHCDip)2+ prefers to form an electron sharing σ‐bond, a dative σ‐bond and two dative π‐bonds with the central C6F4− unit in their doublet states. In contrast, (cAACMe)2 forms two electron sharing σ‐bonds and two electron sharing π‐bonds with the neutral C6F4 unit of 2 in their quintet states. [ABSTRACT FROM AUTHOR]

The carbon suboxide anion C3O2− is generated in solid neon matrix. It is characterized by infrared absorption spectroscopy as well as quantum chemical calculations to have a planar Cs structure where two CO groups with significantly different bond lengths and angles are attached in a zigzag fashion to the central carbon atom. Bonding analysis indicates that it is best described by the bonding interactions between a neutral CO in a triplet excited state and a doublet excited state of CCO−. [ABSTRACT FROM AUTHOR]

The chemistry of organic adsorbates on surfaces is often discussed in terms of Pauli repulsion as limiting factor regarding the packing of molecules. Here we show that the attractive part of the van der Waals potential can be similarly decisive. For the semiconductor surface Si(001), an already covalently bonded molecule of cyclooctyne steers a second incoming molecule via dispersion interactions onto the neighbouring adsorption site. This helps in understanding the nonstatistical pattern formation for this surface–adsorbate system and hints toward an inclusion of dispersion attraction as another determining factor for surface adsorption.