This study examines a variety of compounds containing silicon-phosphorus multiple bonds as well as a selection of hydrogen-bridged species, including a doubly bridged structure. The structures of 29 minima and 37 transition states of the form Si2PHn (n ) 7, 5, 3, 1) have been optimized at the MP2(full)/6-31G(d) level of theory; a representative subset was also optimized at the QCISD/6-311G(d,p)...

The equilibrium properties of the p-bonded Al–ethylene complex in its ground state are calculated by coupled-cluster theory. Significant changes in the geometry of the ethylene molecule upon complexation ~elongation of the CC bond, pyramidalization of the CH2 groups! are consistent with the formation of a chemical bond between fragments. The overall interaction is rather weak because bonding is...

Electronically excited states in CH2Cl and CH2F radicals are studied at the EOM–CCSD/6-311~31, 31!G~3df, 3pd! level of theory. Excited states’ characters and changes in the electronic spectrum in the CH3→CH2F→CH2Cl sequence are interpreted in terms of a simple molecular orbital picture. The key factors determining the electronic structure of these radicals are ~i! the presence of lone pairs on ...

Using ab initio density functional theory, here we systematically study the monolayer ${\mathrm{MoOCl}}_{2}$ with a $4{d}^{2}$ electronic configuration. Our main result is that an orbital-selective Peierls phase (OSPP) develops in ${\mathrm{MoOCl}}_{2}$, resulting dimerization of Mo chain along $b$ axis. Specifically, Mo-${d}_{xy}$ orbitals form robust molecular-orbital states inducing localize...

The results of (low energy) photoelectron spectroscopy render possible a better appreciation of bonding in molecules. The application of the new experimental method is demonstrated utilizing representative phosphorus compounds, and the close symbiosis delineated with molecular orbital models. Among the topics discussed are: the element P4, phosphine PH3 and derivatives, phosphorus substituent e...

Geometry is one of the primary and most direct indicators of aromaticity and antiaromaticity: a regular structure with delocalized double bonds (e.g., benzene) is symptomatic of aromaticity, whereas a distorted geometry with localized double bonds (e.g., 1,3-cyclobutadiene) is characteristic of antiaromaticity. Here, we present a molecular-orbital (MO) model of aromaticity that explains, in ter...

Metal-thiolate active sites play major roles in bioinorganic chemistry. The M--S(thiolate) bonds can be very covalent, and involve different orbital interactions. Spectroscopic features of these active sites (intense, low-energy charge transfer transitions) reflect the high covalency of the M--S(thiolate) bonds. The energy of the metal-thiolate bond is fairly insensitive to its ionic/covalent a...

Recent state-of-the-art crystallographic investigations of transition metal spinel compounds have revealed that the d-orbital charge carriers undergo ordering transitions with the formation of local ‘molecular bonding’ units such as dimers in MgTi2O4, octomers in CuIr2S4, and heptamers in AlV2O4. Herein, we provide a unifying scheme involving one-dimensional (1D) orbital wave (OW) ordering appl...

The results of a theoretical study on the interaction of o-tetrafluorophenylene mercury with ethylene and acetylene are reported. The AM1 molecular orbital semiempirical method is applied through a complete optimization procedure without any restrictions to find the optimal equilibrium geometries. The comparative capabilities of ethylene and acetylene molecules to form stable complexes with o-t...

Easily prepared and highly modular organic amide proligands have been used to synthesize a series of new bis(amidate)-bis(amido) Ti and Zr complexes via protonolysis. These complexes have been structurally characterized by NMR spectroscopy and X-ray crystallography. The solid-state molecular structures of these complexes indicate that the amidate ligands bind to the metal centers in an exclusiv...