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The mechanism of the palladium-catalyzed homocoupling of arylboronic acids ArB[(OH).sub.2] in the presence of dioxygen, leading to symmetrical biaryls, is described. The peroxo complex has played a major role and this reaction is at the origin of the formation of biaryls as byproducts in palladium-catalyzed Suzuki-Miyaura reactions when they are not conducted under oxygen-free atmosphere.

The bond length alternation (BLA )of increasingly long oligomers by using six hybrid functionals and the Hartree-Fock model is calculated. It is shown that inclusion of self interaction corrections (SIC)dramatically improves the computed BLA (compared to pure-DFT) for medium chain lengths.

Ru(II) and Os(II) complexes (P) of[4'-(p-phenyl)]terpyridyl ligand (ptpy) derivatized with an electron acceptor (A) of the triphenylpyridinium (H3TP (super+)) type have been proposed as functional models for electron-transfer (ET) processes in the context of artificial photosynthesis. The ground- and excited state properties of these complexes both in their native and monoreduced forms have been studied by the means of density functional theory.

The dinuclear radical anion complexes like tricarbonylchlororhenium along with alpha-amines like bpy are studied by EPR, as they are important primary activated intermediates in photo or electro catalytic cycles of carbon dioxide reduction. The results showed partially reduced species when azo ligands reacted in chlorinated hydrocarbons and metal-carbonyl stretching vibrations from IR spectroscopy showed low energy shift on reduction.

A theoretical study of the linkage isomerization in [Co(NH3)(sub 5)ONO](super 2+) is presented. The results showed that his reaction is only marginally exothermic in the gas phase, while solvent significantly shifts equilibrium toward the nitro isomer.

Research is presented demonstrating the total bonding and structural analysis, low-lying excited stated and vibronic coupling calculations of the electronic structure of the Creutz-Taube ion by using Density Functional Theory.

An integrated computational method is used to study the structure, conformational behavior and magnetic properties of 1,5-dimethyl-3-phenyl-6-oxoverdazyl radical and 1,1',5,5'-tetramethyl-6,6'-dioxo-3,3'-biverdazyl biradical and of some related compounds. The integrated computational approach includes a hybrid Hartree-Fock (HF)/density functional theory electronic method combined with the polarizable continuum model for describing solvent effects. Its reliability is confirmed by the comparison of experimental data and with refined post HF computations for simplified model compounds.

Research was conducted to examine the magnetic exchange interactions in copper(II) mu-2-azido bridged complexes using different density functionals and both STO and GTO basis sets. The nonorthogonality effects were taken into consideration in the framework of the broken symmetry approach. Results provide a remarkable agreement with experimental data using the new MPW1PW functional and crystallographic geometry.

Research was conducted to examine the structural spectroscopic, electrochemical and magnetic properties of cobalt(II)derivative of (ethylsulfanyl)porphyrazine, Co(OESPz), in comparison with those of a peripherally substituted porphyrin, CoOEP, and of a well-studied tetraazapyrrole complex, CoPc. Results based on density functional calculations reveal that the ligand framework strongly influences the energy of the one-electron levels.

The magnetic properties and the electronic structure of the mixed valence dinuclear complex {Fe2(OH)3(tmtacn)2}2+ were characterized through density functional modeling by substituting the tmtacn ligand with three ammonia molecules. The ground and excited state properties obtained agreed well with experimental values. Moreover, minimum energy path computations enabled the calculation of the frequencies related to the normal coordinate Q- which accounts for the delocalization of the surplus electron.

Research was conducted to examine the electronic structure of Ti(CatNSQ)2 and Sn(CatNSQ)2, where CatNSQ2- is the tridentate radical ligand, using density functional measurements. Measurements revealed that the main exchange mechanism between the organic radicals, responsible for the ferromagnetism of the complexes, was a superexchange pathway mediated by the 3d orbitals of Ti and the 4p empty orbitals of Sn. The crystal structure of Sn(CaatNSQ)2 was solved and the M-O and M-N bond distances were established.

Two classes of head-to-tail expanded pyridiniums (EPs) are designed and their first representative elements are prepared and analyzed. A method is described for predicting the efficiency of photobiscyclization of branched EPs into fused ones, which is based on the analysis of computed difference maps in total electron density for singlet-excited states.

A theoretical study of eosin-Y (EY) loaded ZnO thin films which is the basic component of a dye-sensitized solar cell (DSSC), is presented. The results obtained highlighted strong adsorption of EY on the ZnO substrate which contributed significantly to the electronic structure of the adsorbed system.

A reliable and fast computational method developed for the calculation of p[K.sub.a]* of photoacids is examined. The results obtained from the five coumarins verify the reliability of the model that is developed by combination of density functional theory (DFT) for the excited states, time-dependent DFT, with a polarizable continuum model for solvent.

Density functional theory calculations are used for studying the structural and electronic properties of the derivatives of the N3 complex in order to improve their spectral absorption in the visible region for photoelectrochemical applications. The N3 complex is shown to be a good candidate for enhancing the response of the N3 dye to solar light.

Photoinduced processes occurring within a series of dyads made up of Os(II) bisterpyridyl complexes functionalized by 2,4,6-triarylpyridinium groups T[P.sub.+] are analyzed theoretically using density functional theory. A demonstration of excited-state structural relaxation upon spin-density redistribution is presented.

The adsorption of molecular species, such as [O.sub.2] and CO on model neutral and positively charged clusters is studied using an ab initio approach with the aim of understanding the elementary steps governing the oxidation of CO catalyzed by dispersed or supported gold nanoclusters. The computed structural and thermodynamic data related to the binding process show that molecular oxygen interacts better with neutral clusters, acting as an electron acceptor, while CO more strongly binds to positively charged species, thus acting as an electron donor.

By means of density functional theory (DFT), the ground and excited-state properties of [Ru(bpy)(tpy)dmso](super 2+) (bpy=2,2'-bipyridine, tpy=2,2':6',2'-terpyridine; dmso=dimethyl sulfoxide) are studied. The results highlight the power of DFT approaches in the description of complex transition metal containing systems especially helpful when the properties of the excited states can be only roughly derived from experimental data.