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Several crystalline polymorphs have been discovered for picryl bromide. Among the several forces that control the formation of such polymorphs are the interactions among the nitro groups and phenyl rings of those crystals. Although there are >300 structures to be found in the Cambridge Structural Database displaying the nitro-phenyl interaction, nonetheless this interesting and apparently important, interaction, seems not to have been discussed within any of the papers reporting the structures. In this article, quantum calculations are reported that assess the strength of these nitro-phenyl interactions within a crystal of picryl bromide. The rather flat molecules of picryl bromide are arranged in layered planes within the crystal, and we examine the attractive interactions that occur within a given plane, and between adjacent planes. Calculations of Hartree Fock and Moller Plesset perturbation theory carried to a second-order expansion are used. Both quantum mechanical approximations are implemented with 6-31G* basis functions. Hartree Fock | Moller Plesset perturbation theory | quantum mechanics

Ab initio study of six carbon-to-carbon identify proton transfers is described. There is no correlation between the transition state and the development of aromaticity and charge delocalization has lagged behind proton transfer as is commonly seen in nonaromatic systems involving [pi]-acceptor groups.

Product analyses and nanosecond time-resolved spectroscopy on laser flash photolysis are analyzed for the photoinduced electron-transfer reaction of 3,4-di([alpha]-styryl)furan. A new method is provided for the generation of aryl-substituted tetramethyleneethane (TME)-type intermediates.

The restrictions of [pi]-orbital interactions (GOR) was developed to estimate stabilization energies fro aromatic molecules of various types. The GOR can isolate the [pi] system of a specific group from those of other groups and a substitute effect can be partitioned into the conjugative and inductive parts indicating that the conjugative effect plays the predominant role in determining substituent effects.

Induced current calculations were used to construct maps of the ring currents in two- boron wheel systems. [B.sub.8.sup.2-] and [B.sub.9.sup.2-] were found to be [sigma] aromatic with four active [sigma] electrons and they were also [pi] aromatic with four [pi] electrons.

Different decouplings of the electron propagator were employed to provide theoretical comparison to experimental electron detachment energies for the pyrrolide, imidazolide, and pyrazolide anions. The ab initio electron propagator results were found to be in close agreement with experimental values, and the associated Dyson orbitals provide a detailed catalog of bonding changes as the number and positions of N atoms vary within the set of pentagonal aromatic anions.

Quantum chemistry calculations were performed on the systems of Ca2N6, CaN6, [CaN6.sup.2-], N6, and [N6.sup.4-] at the B3LYP/6-311G* level to explore the possibility of inducing an aromatic N6 ring cation-[pi] interaction. Results reveal that the alkaline earth metal Ca is capable of inducing an aromatic N6 ring through the cation-[pi] interaction formed by electron transfer from the Ca atom to the N6 ring.

Molecular aromaticity in the linear polyacenes is examined by using atoms in molecules based six-center index (SCl-AIM), which measures the electron delocalization. The SCI-AIM values for the linear-polyacenes have shown decreasing aromaticity going from outer to inner rings in the polyacene series and this approach is compared to a Mulliken-like approach.

Resonant electron captures mass spectra of aliphatic and aromatic amino acids and their methyl esters show intense [M-H](super minus) negative ions in the low-energy range. The results have significant implications in biological systems as they suggest that amino acids could serve as radiation protectors since they are found to efficiently thermalize electrons.

A study was conducted about the interaction of large neural aromatic molecules, such as benzene, naphthalene, tetracyanoquinodimethane and DDQ with both metallic and semiconducting single-wall carbon nanotubes (SWNTs) by using the density function theory within the local density approximation. The interaction between small charge transfer aromatic molecules and SWNTs is dependent on the electronic structure of SWNTs and sensitive to the molecular orientation.

Local aromacities of the six-membered rings in the two lowest-lying singlet states of [n]acenes (n= 6- 9) are assessed by means of three probes of local aromacity based on structural, magnetic, and electron delocalization properties. It is found that the inner rings have the largest aromatic character in the closed-shell singlet states, and the outer rings become the most aromatic for the diradical singlet states.

The study of properties of aromatic anion species, which is of fundamental importance, is carried out, to understand the relationships between proton transfer in self-assembled monolayers on metal surfaces and nonlinear optical properties in solution and in crystals. Results of polarizabilities of aromatic anions have shown that benzenesulfinate is an anion with exceptional values for beta and that the benzenethiolate shows large values of gamma compared with the rest of anions.

An attempt is made to generate and characterize a triplet carbene, bis(2,4,6-trichlorophenyl)carbene ((super 3)1), in zeolites Y and L and in a molecular sieve VPI-5 in which a possible dimerization and reaction with the precursor of carbene are significantly retarted, thus making the triplet carbene longer lived than in solution at room temperature. A triplet carbene was generated and characterized in a zeolite for the first time and shown to be stabilized extrinsically.

Several homodesmotic aromatic stabilization energy (ASE) reaction systems are examined to demonstrate the role played by these factors in the calculation of an ASE value for the fluorenyl cation. The magnitudes of the derived ASE are quite similar for four, very different determinative, homodesmotic reaction systems, giving strong support to the inherent accuracy of the final derived ASE value.

The comparison of the adsorption of benzene, naphthalene, and anthracene molecules on Pt(111) surfaces is studied. Periodic density functional theory (DFT) calculations are presented for this purpose.

The dynamics of the polyaromatic cores are of vital importance as they help in examining the electrical conductivities of the columns. It is found that the dynamics of the inner core and the alkyl tails of discotics are strongly correlated.

The studies was conducted to calculate the complexes formed by variety of anions with perfluoro derivatives of benzene, napthalene, plyridine, thiophene and furan using DFT (B3LYP/6-31++G(super **) and MP2)6-311++G(super **)) ab initio methods. The AIM analysis of the electron density showed a variety of topologies depending on the aromatic system considered.

Research is done on the radical anions of aromatic diimides, which are implicated in a wide variety of photochemical electron transfer reactions. The results impose design constraints on the use of these excited radical anions as electron donors in electron-transfer systems targeted towards molecular electronics and solar energy conversion.

The symmetric polygonal structures of Ni(sub n) rings in the tiara Ni thiolates, [NiS(sub 2)](sub n) and [Ni(SR)(sub 2)]n (n = 3-6) primarily arise from the effective delocalization of the d-orbital electron across the Ni(sub n) rings leading to bond length equalization and thereby aromaticity. These d-orbital rings are introduced to explain the polygonal structures of cyclic metal rings bridged by thiol linkages.

An atoms-in-molecules (AIM) and electron density localization function (ELF) critical point analysis for two types of lemniscular system, each of which displays double-half-twist Mobius topology is reported. The results obtained provide insight into the consequences of the (enforced) [pi]-[pi] stacking at the cross-over point of the lemniscate.

The local electronic structures of the different isomers of dicarba-closo-dodecarboranes [C.sub.2][B.sub.10][H.sub.12] are studied. The approach is found to be extremely useful for conducting the excited state calculations of aromatic polyhedral boranes and related systems.

The mechanistic studies of the Heck-Mizoroki reaction of a vinylboronate ester with different aryl iodides have indicated that electron donors accelerate cross-coupling. The dienylboronate ester is converted through a series of highly stereoselective iodo-deboronations and Heck-Mizoroki reactions into a trienyl iodide precursor in order to use in the total synthesis of viridenomycin.

Two new aromaticity index based on the analysis of electron delocalization in aromatic species using the quantum theory of atoms-in-molecules are defined. One of these indexes is para-delocalization index (PDI) that measures the electronic delocalization between para-related carbon atoms in six-membered rings. Study is presented to show that this index can be partitioned into individual molecular orbital contributions.

A series of different aryl-donor groups (Ar) around a central platform is studied to evaluate the very fast intramolecular electron movement among these tethered redox centers, and the delocalization possible within p-doped aromatic cofacial arrays. It is observed that at transition temperatures of about -20 degrees Celsius, the electron-transfer dynamics becomes barrierless, since the whizzing occurs beyond the range of states and effectively achieves complete pi-delocalization.

The scope and limitation of the asymmetric nucleophilic aromatic substitution reaction of [alpha]-substituted 1,3-dicarbonyl compounds and activated aromatic systems catalyzed by N-benzyl-O-benzoylcinchoninium or cinchonidinium salts are presented. Various 1,3-dicarbonyl compounds and activated aromatic systems are evaluated for the aromatic nucleophilic substitution reaction, and it was found that the yield and enantioselectivity are very dependent on the substrate and reagent.

Polyaromatic molecules were found capable of precipitating DNA-solubilized single-walled carbon molecules from solution through a competitive binding mechanism whereby DNA is displaced from the nanotube surface, allowing nanotubes to rebundle. The findings were diversified to include techniques for controlled desolubilization and to provide additional elucidation into the interaction of single walled carbon nanotubes and noncovalent solubilizing agents.

Oxidative cyclodehydrogenation is an important process in the formation of the new graphene, N-1/2HSB, which results from the FeCl3-catalyzed oxidative cyclodehydrogenation of 1,2-dipyrimidyl-3,4,5,6-tetra-(4-tert-butylphenyl)benzene. The new ligand N-1/2HSB, its Ru(II) complexes and also the half-cyclized N-1/2HSB are characterized by (super 1)H, NMR, infra-red (IR), ESI-MS, and accurate aromatic ligands.

Aromaticity and homoaromaticity of a parent barbaralane and a tetraphosphabarbaralane of C2-symmetry are visualized by means of three-dimensional nucleus-independent chemical shift (NICS) maps. The characteristic response properties of the electronic structure of these molecules are highlighted.

A study was conduct to show the transport and electronic structure measurements on rigid, conjugated oligoacenes of increasing length with either thiol (-S) or isocyanide (-CN) linkers. The smaller offset observed for the aromatic thiols should produce more effective coupling between states in the metal and the HOMO level of the molecules, thereby reducing the effective barrier to tunneling at the contact.

The first unambiguous case of bond forming reactions of medium-sized organic dications with maintenance of two charges was reported. A new route for the gas-phase synthesis polyaromatic hydrocarbons (PAH) in the extremely cold and diluted conditions of interstellar manner was proposed.

The synthesis and characterization of stable phosphanylidene-sigma(super 4)-phosphoranes such as Mes*P = PMe3 and 2,6-Mes2C6H3P = PMe3 is reported. Studies indicate potential catalytic role of phosphine in chlorine atom transfer processes.