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A detailed picture of the structural distortions suffered by a water molecule in direct contact with small inorganic anions is emerging from a series of vibrational spectroscopy studies of the gas-phase X(super -.)H2O binary complexes. The behavior of H(sub 2)O in the X(super -.)H(sub 2)O (X= Br, CL, F, O, and OH) complexes, which all adopt symmetric structures where one hydrogen atom is H- bonded to the ion while the other is free, is highlighted.

A new type of mixed-ligand Pt(II) complexes, Pt([R.sub.2]SO)(pyrazine) [Cl.sub.2], was synthesized from the aqueous reaction of K[Pt([R.sub.2] SO)[Cl.sub.3]] with pyrazine. The compounds were characterized mainly by IR and multinuclear magnetic resonance spectroscopies ([sup.1]H, [sup.13]C, and [sup.195]Pt) and crystallography. Compounds with dimethylsulfoxide, tetramethylenesulfoxide, di-n-propylsulfoxide, di-n-butylsulfoxide, dibenzylsulfoxide, and diphenylsulfoxide were studied. IR spectroscopy suggested a cis geometry for the di-n-propylsulfoxide complex and trans geometry for the other compounds. The [sup.195]Pt NMR resonances of the complexes were observed between -3042 and -3121 ppm, with that of the diphenylsulfoxide complex being at higher field than those of the others. The pyrazine [sup.3]J([sup.195]Pt-[sup.1]H) coupling constant was observed for the DMSO compound (33 Hz), suggesting a trans geometry. No J([sup.195]Pt-[sup.13]C) coupling could be detected. The crystal structures of trans-Pt(tetramethylenesulfoxide)(pyrazine) [Cl.sup.2] and of cis-Pt(di-n-propylsulfoxide)(pyrazine)[Cl.sub.2] were determined and confirmed the geometry suggested by IR and NMR spectroscopies. The compound with di-n-butylsulfoxide could not be isolated, because it rapidly formed the pyrazine-bridged dimer. Key words: platinum, sulfoxide, pyrazine, crystal structure, NMR, IR.

The synthesis and properties of a new family of [pi]-extended dipyrrins capable of forming brightly fluorescent complexes with metal ions are reported. The metal complexes are observed to possess tunable spectral bands and exhibited different emission properties depending on the mode of metal coordination.

The form of 8-hydroxyquinoline in different solvents is examined by using spectroscopic and computational methods. The results have shown that 8-hydroxyquinoline has displayed a clear preference for the cis conformation, but a small fraction of the trans conformation is present in water solutions.

[super 27]Al nuclear magnetic resonance spectroscopy is used for studying the compositions in the [Ln.sub.2][O.sub.3]-[Al.sub.2][O.sub.3]-Si[O.sub.2] (Ln = Y or La) ternary phase diagram. The results obtained both on glasses and in situ at high-temperature have indicated a preferential localization of [Ln.sup.3+] nearby tetra-coordinated aluminum species, with possible formation of tricluster and/or [Ln.sup.3+] coordination changes.

The effects of the central metal ion on the vibrational dynamics of ligands are examined by using a vibrational circular dichroism (VCD) study on two kinds of tris-chelated complexes with a series of different metal ions. The results have shown that the modes representing the interligand correlative vibrations of C-O stretches are affected by the type of central metal ion.

Conventional radiationless transition approach is discussed to study exciplex emission spectra and rate constants of decay via internal conversion and intersystem crossing. It is demonstrated that exciplex decay gives evidence of radiationless quantum transition mechanism rather than thermally activated medium reorganization electron transfer (ET) reactions mechanism.

The emission properties of an erbium organic complex embedded in a polymer matrix are examined for laser and optical amplification applications in the 1550 nm telecommunication range. The results have shown that organic polymer hosts doped with erbium complexes have a great potential for amplification in the telecommunication spectral range, as they have displayed high gain cross section as compared to other erbium-containing materials.

The effect of lithium ion coordination with the bis(oxalate)borate [BOB.sup. -] [B[(C2O4).sub. 2]].sup.-] anion in DMSO, PEG, PPG and d-PPG is studied in detail by IR and Raman spectroscopy. The Raman spectra and the calculations together indicate that [Li.sup.+] coordinates bidentately with two end-oxygen atoms of the [BOB.sup. -] anion.

The characterization of imidazole (IM), imidazole dimer (IMD) and imidazole-water (IMW) binary systems formed in helium nanodroplets using infrared laser spectroscopy is presented. On comparing the experimental results with the ab initio calculations it was found that vibrational transition moment angles provide conclusive assignments for the various complexes including IM, one isomer of IMD and two isomers of IMW binary complexes.

The synthesis of conjugated rigid rod and nonconjugated flexible polymers and corresponding model compounds bearing the d(super 9)-d(super 9) M(sub 2)(dppm)(sub 2)(super 2+) fragments (where dppm=bis(diphenylphosphino)methane) is reported. The presence of pi-delocalization between the M(sub 2)(dppm)(sub 2) fragments is addressed using the comparison between aryl- and alkyl-diisocyanide assembling ligands.

The synthesis of novel four-coordinate boron complexes that contain the mixed phenol-pyridyl functional group is explored. Single-crystal X-ray diffraction demonstrates that the molecular packing is sensitive to the aromatic groups attached to the boron center, although the molecular structures are very similar to each other among compounds.

The formation and dissociation of organic solvent-solute complexes are investigated by performing temperature-dependent linear Infrared (IR) absorption experiments and two-dimensional (2D) IR nonlinear vibrational echo measurements. The results have shown that 2-ethoxyphenol (2EP) do not form complexes to any extent and density functional calculations have suggested that steric effects caused by the extra methyl group in 2EP are responsible for the difference.

The crystal structure, magnetic properties, and 57Fe Mossbauer spectroscopy of the two-dimensional coordination polymers [M(1,2-bis(1,2,4-triazol-4-yl)ethane)2(NCS)2] are discussed. [Fe(btre)2(NCS)2] is found to retain a HS ground state upon cooling from 293 K to 8 K.

A report that axial ligand substitution of a mononuclear nonheme oxorion(IV) complex, [Fe(super IV)(O)-(TMC)(NCCH3)](super 2+), leads to the formation of new Fe(super IV)=O species with relatively intense electronic absorption features in the near-UV region is presented. The presence of these near-UV features permits the first observation of Fe=O vibrations using resonance Raman spectroscopy.

A series of isostructural dimeric manganese complexes of the type [(Me4dtne)Mn2(Mu-O)2(Mu-R)](super 2+)[X(super -)](sub 2) are prepared and characterized. The dimanganese cores of the complexes are rigidly held together by the hexadentate ligand Me4dtne (Me4dtne = 1,2-bis(4,7-dimethyl-1,4,7-triazacyclonon-1-yl)ethane).

Photoinduced reactions in the complexes of Mg(super +1)(OCNC2H5)(sub n) (n=1-3) are studied as a function of the number of solvent molecules. Photodissociation action spectra of Mg(super +1)(OCNC2H5)(sub 1-3) were recorded in the spectral range of 230-440 nm.

The evidence of specificity of molecular recognition within the hydrophobic core of a metal-assembled homotrimeric coiled coil protein is examined. The noncovalent binding of the organic ligands within designed protein cores is investigated.

The method for tuning the tris(5-aryl-8-quinolinolate)Al(III) (Alq3) emission from blue-green to yellow and red through attaching electron rich and poor aryl moieties to the 5-position of the quinolinolate ligand, is presented. It is concluded that a successful tuning in the emission color is achieved.

Research has been conducted on isonitrile complexes. The authors describe the preparation and structural and spectral characterization of these complexes.