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A series of novel organometallic sandwich molecular wires (SMWs) are constructed with alternating iron atoms and cyclopentadienyl (Cp) rings by using density functional theory (DFT) and nonequilibrium Green's function techniques. The studies have shown that the SMWs are good materials for using in molecular electronics.

Density functional theory (DFT) is used for assessing the [pi]-acidity and [pi]-basicity of metal-organic trimetallic macromolecular complexes of the type [[M([mu]-L)].sub.3], where M = Cu, Ag, or Au and L = carbeniate, imidazolate, pyridiniate, pyrazolate or triazolate. The results have indicated that the metal-organic macromolecules have shown superior [pi]-acidity and -basicity when compared to their organic counterparts.

The influence of molecular geometry, type of exchange-correlation functional, and contraction scheme of basis set applied at the iron nuclei in the calculation of [super.57.Fe] Mossbauer isomer shifts and quadrupole splittings for a wide range of ligand types in inorganic and organometallic systems is studied. Results suggest the use of only pure exchange-correlation functionals for accurate prediction Mossbauer spectra parameters in ferrocenes.

A large and diverse data set is presented which is used for testing existing density functionals and developing new ones. The most highly recommended functionals for accurate predictions of energetics and bond lengths of inorganometallic and organometallic compounds are G96LYP, followed closely by MPWLYP1M, XLYP, BLYP, and MOHLYP.

The electrochromic linear and nonlinear optical properties of alkynylbis(diphosphine)ruthenium complexes are examined. A combination of cyclic voltammetry, UV-vis-NIR spectroelectrochemistry, and time-dependent density functional theory is used for this purpose.

Research gas-phase molecular association reactions of dimethylaluminum hydride have been studied with density functional theory (DFT) and ab initio MP2 methods to understand the dimer trimer equilibrium. In conclusion, on the basis of the current results, experimental observations of a complex DMAH dimer trimer equilibrium can be understood in terms of a series of the slow, bimolecular and relatively faster unimolecular reactions.

The methanolytic cleavage of a series of O,O-dimethyl O-aryl phosphorothioates (1a-g) catalyzed by a C,N-palladacycle, (2-[N,N-dimethylamino(methyl)phenyl]-[C.sup.1],N)(pyridine)palladium(II) triflate in methanol is described along with data for the methanolytic cleavage of 1a-g. The results have provided an example where a palladacycle-promoted solvolysis reaction has displayed a break in the Bronsted plot showing at least one intermediate, while the DFT calculations have provided insights into a more complex mechanism involving two intermediates.

Density functional theory (DFT) is used for studying the geometric and electronic structure of [[(PCN)Pt[double bond]O].sup.+], composition in solution and reactivity. Stabilization of the Pt-oxo bonding is ascribed to bending of the terminal oxo ligand out of the plane of the complex and to the transfer of electron density from compact low lying Pt 5d orbitals to more diffuse 6s and 6p orbitals.

Scanning tunneling microscopy (STM) is used to image and study the [{Cp*(dppe)Fe(C[triple bond]C-)}.sub.2](1,3-[C.sub.6][H.sub.4]) both as a neutral molecule, Fe(II)-Fe(II), and as a mixed-valence complex, Fe(II)-Fe(III). The observation of charge localization in mixed-valence complexes outside of the solution environment offer new routes for the control and patterning of charge on surfaces which could find potential applications in smart materials and molecular electronic devices.

The cationic functionlization of metallabenzenes [Ir([C.sub.5][H.sub.4]{SMe-1})([[kappa].sup.2]-[S.sub.2]CN[Et.sub.2])[(P[Ph.sub.3]).sub.2]]PF6 and [Os([C.sub.5][H.sub.4]{SMe-1})[(CO).sub.2][(P[Ph.sub.3]).sub.2]][C[F.sub.3]S[O.sub.3]] through regioselective nucleophilic aromatic substitution of hydrogen is described. The results from DFT calculations rationalized the preferred sites for nucleophilic attack at both the metallabenzene rings position.

ESI-MS, isotope labeling studies and DFT calculations were performed to study the reaction mechanism of cis-dihydroxylation of dimethyl fumarate with oxone catalyzed by the iron complexes of a macrocyclic tetraaza ligands. The cis-dihydroxylation reactions involving cis-HO-[Fe.sup.V]=O and cis-O=[Fe.sup.V]=O species both proceed by a concerted but highly asynchronous mechanism, with that involving cis-HO-[Fe.sup.V]=O observed to be more favorable due to a smaller activation barrier.

NMR-Spectroscopic and s olid-s tate studies are conducted to gain insight into the dimeric structures in cometal-free asymmetric conjugate addition reactions of dialkylzinc reagents with aldehydes. X-ray structure determination of a zinc complex with a [2.2]paracyclophane ligand are supported by the DFT calculations for the structures of the zinc complexes of monomeric and dimeric species.

Density functional theory and multiconfigurational quantum chemical studies were performed to differentiate nitride versus oxide in polymetallic uranium molecules containing [(N).sup.3-] and [(O).sup.2-]. The crystallographic data obtained provide insight into the electronic structure and unique chemical bonding of uranium polymetallic compounds.

The preparation and x-ray structural studies of Gold(I) bis(acetylide) complexes [PPN][Au[R.sub.2]] where PPN = bis(triphenylphosphine)iminium) and R = ethisterone (1); 1-ethynylcyclopentanol (2); 1-ethynylcyclohexanol are described. The gold polymorphs are found to exhibit different emission energies with colors ranging from blue to yellow solid state and the DFT calculations provide insight into the orbitals involved in the electronic transitions of gold polymorphs.

The first example of electrophilic insertion of a terminal nitride into an aromatic C-H bond is reported. The two-step exotherimic reaction mechanism is supported by differential scanning calorimetry and thermogravimetric analysis.

Highly stereospecific, palladium-catalyzed decarboxylative allylation of allyl sulfonylacetic esters which allows the stereospecific formation of tertiary homoallylic sulfones in high yield. The results indicated that allylation of the intermediate [alpha]-sulfonyl anion is more rapid than racemization, leading to a highly enantiospecific process.