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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.

Research has been conducted on bisannulated acridines. The biosynthetic origin of these compounds and their structural and biological activities have been investigated, and the results are reported.

Research into carbon-to-carbon identity proton transfer from ketene, allene, thioketene and ketenimine to their respective conjugate anions in the gas phase is presented. It was demonstrated that the acidities are all higher while the barriers are lower than for the corresponding CH3CH=X series.

Results reveal that the transition states of the proton transfer reactions are not in balance despite the absence of correlation between the degree of imbalance and the pi-acceptor strength of the Y group.

An ab initio study of the identity of carbon-to-carbon proton transfers between nitromethane and nitromethide anion and between oxygen protonated nitromethane and aci-nitromethane was reported. Transition state imbalances were shown to cause slight decrease in intrinsic gas phase barriers. Dependence of the barriers on the pi-acceptor was observed to be a result of complex reactions among resonance, inductive and hydrogen bonding effects.

Rate constants for the deprotonation of 2-nitro-4-X-phenylacetonitrile, 2-X (X = NO2, SO2CH3, CN, CF3, Br and Cl) by piperidine and morpholine and for the reverse reaction were determined in 90% Me2SO-10% water, 50% Me2SO-50% water and water (X = NO2, SO2CH3, CN only). There was an imbalance which is consistent with a transition state in which delocalization of the negative charge into the 2-nitrophenyl moiety lags behind proton transfer.

The identity carbon-to-carbon proton transfer between oxygen-protonated acetaldehyde (syn and anti) and acetaldehyde enol (syn and anti) was examined by ab initio methods at the 6-311+G**//6-311+G**, MP2/6-311+G**/6-311+G**, and MP2/6-311+G** levels. The transition states of all reactions under study indicate a strong imbalance because the charge shift in the product enol lags behind proton transfer and the charge shift in the reactant enol is ahead of proton transfer.

Ab initio calculations are employed to analyze the imbalance in the transition state of proton transfer step in the acetaldehyde to its enolate ion reaction. A charge imbalance toward charge delocalization is observed in the transition state of the gas phase reaction due to tightness and large positive charge on the protons. Imbalance in solution phase is higher than the gas phase due to solvation.

An ab initio study of two series of carbon-to-carbon proton transfer reactions is conducted to examine the degree of aromaticity of [C.sub.4][H.sub.4]X (X = CH(-), NH, S, O, PH) and the antiaromaticity of [C.sub.4][H.sub.4]X (X = AlH, BH) is expressed at the transition state of the proton transfer and its effect on the respective intrinsic barriers. The results revealed a disproportionately large degree of aromaticity at the transition state for the aromatic systems and a disproportionately small degree of transition state antiaromaticity for the antiaromatic systems.

A systematic analysis of the candidate structures of spiroleucettadine, a sponge with a bicyclic core meager in H-atoms, is performed by using density functional theory calculations. The results have provided a revised structure of spiroleucettadine, a bicyclic sponge alkaloid with a scarcity of H-atoms in its core.

The experimental data on the kinetic and thermodynamic acidities of pentacarbonyl(cyclobutenylidene)chromium complexes in acetonitrile is presented. Results of the gas phase ab initio calculations indicate that in the gas phase, the effect of antiaromaticity on the thermodynamic acidities is large but strongly attenuated in acetonitrile.

Research has been conducted on carbon-to-carbon proton-transfer. The authors describe the results of ab initio study of the proton-transfer identity in the gas phase, and discuss the effects of the cyano group on the proton-transfer barriers, transition state structure and acidities.

The carbon-to-carbon identity proton transfer was studied from ketene to its gas phase anion.