The water-promoted hydrolysis of a highly twisted amide is studied using density functional theory in conjunction with continuum dielectric method to introduce bulk solvent effects. aim these studies reveal how the twisting C−N bond affects neutral amides. To do so, both concerted and stepwise mechanisms are results compared ones from an undistorted used as reference. In addition, extra explicit water molecule that assits required proton-transfer processes taken into account. Our predict...

<italic>Ab initio</italic> computations show that the global minimum structure of CBe₅Li_nⁿ⁻⁴ clusters (<italic>n</italic> = 1 to 5) contains a planar pentacoordinate carbon atom.

Time-dependent density-functional theory (TDDFT) is used to study the excitation energies of global minima small Zn(i)O(i) clusters, i = 1-15. The relativistic compact effective core potentials and shared-exponent basis set Stevens, Krauss, Basch, Jasien (SKBJ), systematically enlarged with extra functions, were throughout this work. In general, calculated excitations occur from nonbonding p orbitals oxygen. These are perpendicular molecular plane in case rings normal spheroid surface for 3D...

We report a new sandwich-like structure (Al4TiAl42-) based on the recently synthesized all-metal aromatic Al42- squares. This has two squares (-2 charged each) trapping titanium +2 cation. These have been detected by various metallic counterions, with global charge of -1. Thus, we also characterized similar interacting one and sodium atoms charges -1 0. The properties these compounds strongly support idea that they may be formed

In recent years, BN fullerenes have been synthesized experimentally. As their carbon counterparts, these could be assembled in molecular solids, but this possibility has studied little the literature. work, we focus on smallest fullerene, B12N12, which is built by squares and hexagons. First, interaction between two of analyzed, using hybrid B3LYP MPW1PW91 density functional methods. Two different interactions dimer, a square facing (S−S) hexagon (H−H). both cases, B N. The most stable dimer...

A systematic study of cation-pi interactions between alkali metal ions and the cyclopentadienyl ring ferrocene is presented. The (Li+, Na+, K+, Rb+, Cs+) salts ditopic mono(pyrazol-1-yl)borate ligand [1,1'-fc(BMe2pz)2]2- crystallize from dimethoxyethane as multiple-decker sandwich complexes with M+ bound to pi faces rings in an eta5 manner (fc = (C5H4)2Fe; pz pyrazolyl). X-ray crystallography lithium complex reveals discrete trimetallic entities each ion being coordinated by only one ring....

A series of clusters with the general formula CBe(5)E(-) (E = Al, Ga, In, Tl) are theoretically shown to have a planar pentacoordinate carbon atom. The structures show simple and rigid topological framework-a EBe(4) ring surrounding C center, one Be-Be bonds capped in-plane by fifth Be system is stabilized network multicenter σ in which central atom acceptor, π systems as well donates charge E atoms that encircle it.

The aromaticity of dicupra[10]annulenes closely resembles that naphthalene.

This work presents a novel approach to distribute orbitals into subspaces within electron-pairing-based natural orbital functionals (NOFs). modifies the coupling between weakly and strongly occupied by applying an alternating sorting strategy. In contrast previous that enforced electron pairing of contiguous orbitals, new provides greater flexibility, enabling calculation scheme where size can be gradually expanded. As consequence, one start using only (perfect pairing) progressively enlarge...

Several structures of small CdiXi clusters, i ≤ 16, have been characterized. Ringlike found to be the lowest lying for 5 clusters and three-dimensional spheroid larger ones, = 6−16. This trend has ascribed stability obtuse X−Cd−X angles in first case gained from higher coordination second case. The may envisioned as being built Cd2X2 squares Cd3X3 hexagons, it was ZniOi, X O, S, Se, Te, CdiOi structures, studied previously our group. Second-order free-energy differences reveal that most...

The stable isomers of the ferrocene--lithium cation gas-phase ion complex have been studied with hybrid density functional theory. method calculation chosen has tested checking its performance for more protonated ferrocene species. Our calculations demonstrate that procedure used is reliable. We found two separated by a barrier 25.6 kcal/mol. most isomer this Li(+) on-top one cyclopentadienyls, while in least binds central iron metal. latter characterized as planetary system sense thermally...

We present an ab initio study of the pKa a series twisted amides in aqueous solution. The shift with respect to known value for trimethylamine (TMA) is used evaluation. Calculations were made density functional theory using B3PW91 functional. Aqueous solvent effect introduced by use polarizable continuum model. protocol tested on tertiary amines and amides, good agreement available experimental data found. Finally, mechanistic implications change basicity nitrogen as function twist amide...

Sandwich structures are readily formed with the aromatic N42− anion. The complexes, which form early- and late-transition-metal centers described their properties analyzed. These sandwich complexes can oligomerize or polymerize to multidecker chains. Supporting information for this article is available on WWW under http://www.wiley-vch.de/contents/jc_2002/2004/z460498_s.pdf from author. Please note: publisher not responsible content functionality of any supporting supplied by authors. Any...

We report on novel sandwichlike structures [Al(4)MAl(4)](q-) (q=0-2 and M=Ti, V, Cr, Zr, Nb, Mo, Hf, Ta W) based the recently synthesized all-metal aromatic Al(4)(2-) square ring. The have two tetraaluminum rings which trap a transition-metal cation from either first, second, or third row. stability of anionic complexes towards electron detachment is discussed, addition alkali cations found to stabilize 2- charged complexes, preventing spontaneous detachment. Once are formed, properties...

The catalytic, enantio- and diastereoselective addition of hydantoin surrogates II to "rigidified" vinylidene bis(sulfone) reagents is developed, thus overcoming the inability commonly employed β-substituted vinylic sulfones react. Adducts are transformed in enantioenriched 5,5-disubstituted hydantoins through hydrolysis reductive desulfonylation processes providing new structures for eventual bioassays. Density functional theory studies that rationalize observed reactivity stereoselectivity...

The structure, energetics, vibrations, and barrier to internal rotation around the N···H−O hydrogen bond of binary pyridine−formic acid complex are calculated using one properly selected hybrid density functional theory procedure. calculations demonstrate that most stable isomer has a strong hydrogen-bonding interaction, whose strength is enhanced by presence an agostic interaction between carbonylic oxygen α pyridine. Rotation N···H−O, which prevents such occur, results in decrease bonding...

Density functional theory and a polarizable continuum model are used to (i) understand the affinity modulating mechanisms of interaction between metal-ion-dependent adhesion site (MIDAS) selected integrin, lymphocyte function-associated antigen-1 (LFA-1) ligand mimetic acetate molecule (ii) propose new, promising family inhibitors block integrin with intercellular molecule-1 (ICAM-1). We quantify effect isolated factors, such as metal coordination, nature or cation present on MIDAS,...

Multiconfigurational high-level electronic structure calculations show that the Al3(-) ring-like cluster anion has three close low-lying states of different spin, all them having strong multiconfigurational character. The aromaticity has, therefore, been studied by means total electron delocalization and normalized multicenter indices evaluated from wave functions each state. lowest-lying singlet triplet are found to be highly aromatic, whereas next state, quintet much less, though...