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The reaction of copper(II) perchlorate with the macrocyclic ligand [22]py4pz in the presence of a base leads to formation of a dinuclear complex [Cu2([22]py4pz)(mu-OH)](CIO4)3.H2O, in which two copper ions are bridged by a single mu-hydroxo bridge. The mu-hydroxo bridge mediates a strong antiferromagnetic coupling (2J=-694-1(35) cm(super -1) between the metal centres leading to relatively sharp and well resolved resonances in the H NMR spectrum of the complex in solution.

Research has been conducted on manganese complexes which represent functional, structural and spectroscopic system for manganese catalases. The synthesis, characterization and catalase activity of these complexes have been investigated and the details are reported.

Crystal structures suggest that the type-3 copper proteins, tyrosinase and hemocyanin possess a dinuclear copper center and similar spectroscopic properties. They are evolutionarily and functionally related as well. However, catechol oxidase exhibits a diverse function as suggested by its three-dimensional structure.

The reinvestigation of the molecular structure of the parent molecule N(sub 4)P(sub 4)F(sub 8) by using x-ray diffraction, gas electron diffraction and differential scanning calorimetry is described. The results from each of these measurements support a nonplanar eight-membered ring for N(sub 4)P(sub 4)F(sub 8) that is puckered and that undergoes a phase transition at -74 degrees C.

The heteropolyanions (Bi2W22O74(OH)2)12- and (X2W20M2O70(H2O)6)(14-2n)- (X = Sb3+, Bi3+; M(super n+) = Fe3+, Co2+, Zn2+) were synthesized as alkali metal and ammonium salts, respectively. They were characterized by elemental analysis, infrared spectroscopy and X-ray crystallography. These tungsto bismutates and antimonates have one common characteristic: the trivacant beta-B-XW9O33 Keggin fragment as the structural building unit.

The dienes' epoxidation was facilitated by the novel manganese(II)-substituted heteropolyanions, [(MnII-(H2O)3)2(WO2)2(BiW9O33)2]10-, [(MnII-(H2O)3)(SbW9O33)2]12- and [(MnII(H2O)3)2(MnII(H20)2)2(TeW9O33)2]8-. X-ray structure analyses, chromatography/mass spectrometry and ultraviolet visible studies were performed. The findings revealed the enhancement of catalytic performance as shown by the model substrate (R)-(+)-limonene displaying regioselectivity even in the presence of small molar excess of hydrogen peroxide.

Homoleptic [NEt4]2{TI(1,2-(mu-S)2C6H4)}2] ([NEt4]) and [NEt4][TI(1,2-S2C6H4)2] (NEt4) thiolate complexes were synthesized by the salt elimination reaction of cationic thallium and anionic thiolates. The thallium(I) complex is composed of a linear chain of thallium atoms that are aligned to the a-axis without bridging interactions. The complex also contains S2C6H4 fragments that are co-planar with the bc-plane. The formation of linear chains of thallium atoms is due to the Tl-Tl interactions between the dimeric units.

The active site of urease is modeled using the dinuclear nickel(II) complexes of symmetric and asymmetric polydentate ligands. The complexes are studied for their x-ray structure as well as spectroscopic and magnetic properties to evaluate their reactivities. They are then synthesized to mimic the structure and function of the dinuclear active site of urease. Results show that the dinuclear centers of all the complexes are bridged by the alkoxy donor of the ligand and a carboxylate function. The data also suggest that their magnetic and spectroscopic properties are very similar to those of urease.

Dinuclear copper complexes containing tridentate dinucleating ligands are prepared and considered as structural and functional models for catechol oxidases. In these complexes, the Cu(II) centers undergo antiferromagnetic coupling. The crystal structure of the complexes remain unchanged in the methanolic solution. The copper complex of 1,5-bis(2-benzimidazolyl)-3-pentanol exhibits catecholase activity by oxidizing 3,5-di-tert-butylcatechol to quinone.

The structure of the dinuclear nickel(II) complex Ni2(ppepO)(C6H5COO)2(CH3COOH) ClO4 C4H10O was characterized by X-ray crystallography. The asymmetric cation of the complex displayed a monodentate acetic acid molecule located at the coordination site of the less highly coordinated Ni(2). The nickel ions were connected by the benzoate anions with similar C-O bond lengths, and also by the alkoxo donor of the ligand. The conditions provided by the dinuclear active sites was facilitated by the asymmetric relation of the metal ions which enhanced the catalytic action of the dinuclear enzymes.

The synthesis and characterization of the antitumor active platinum compound (bis N-methylimidazol-2yl carbinol)dichloroplatinum(II) are described. The complex showed preference for G-N7 binding based on its interaction with short DNA fragments. The inactivity of its analog dichloro(N1,N1'-dimethyl-2,2'-biimidazole)platinum(I) has been attributed to differences in steric and kinetic properties.

The reaction of (Pt(bmik)(H2O)2)(2+), where bmik is bis((N-methylimidazol-2-yl)ketone), with the bases 9-methylguanine and 1-methylcytosine yields mononuclear complexes. The reaction of the bmik diaqua complex with 1-methylthymine and 1-methyluracil yields dinuclear complexes. X-ray studies of the complexes reveal a head-to-tail arrangement in the bases. The properties and complexing behavior of cis-DDP and Pt(bmik)Cl2 toward nucleobases are compared.

Germanium dibromide undergoes metathesis reactions with sodium salts of benzene thiol, benzene selenol and ethane diol in mixed diethyl ether-methanol solutions to yield various Ge(II) thiolato and selenolato complexes. X-ray studies of these crystals reveal that the complexes contain trigonal pyramidal Ge(II)S3 or Ge(II)Se3 cores. Mononuclear Ge(IV) complexes deviate from the ideal T(d) symmetry. IR and Raman spectroscopic studies help characterize the complexes.

CuBr2 and sodium benzoate react with 2, 6-bis(morpholinomethyl)-4-methylphenol (Hbmmk) yielding two novel mu4-oxo-bridged tetranuclear copper(II) complexes. X-ray crystallography, magnetic measurements and NMR techniques reveal the molecular structure, magnetic properties and spectra properties of the complexes, respectively. The Cu(II) cluster complexes are the first members of this class to have chelating ligands.

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