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The complexes of copper and nitrocatechol dioxygenases are analyzed by x-ray crystallogrphy and various spectroscopies. The activity of catechol dioxygenase is proved.

Copper(I) and copper(II) flavonolate complexes with the tridentate ligand isoindoline were prepared, oxygenated to copper o-benzoylsalicylate complexes and carbon monoxide, and used as catalysts for the oxygenations of flavonol in reactions that mimic the quercetinase enzyme reaction. The crystal structures of a copper(II) flavonolate complex with indH and that of (O-benzoylsalicylato)copper(I) complex are reported.

Research was conducted to examine in detail the synthesis and characterization of (Cu(PPh3)2(fla)) (fla = flavonolate) and (Cu(PPh3)2(O-bs)) (O-bs = O-benzoylsalicylate). The crystallographic characterization of the complex has demonstrated that the coordination geometry of the molecule is tetrahedral. The details of the oxidative ring cleavage reaction supported by 18O-labeling and kinetic experiments are also reported.

The presence of copper enhances the selectivity and direction to the amine condensation process of the oxidation chemistry of trihydroxyphenylalanine models. The three synthetic reaction series of Cu(II), Cu(I) and Cu(0) produces Cu(py)2(Cat-N-SQ) as a major product. The oxidative dimerization of iminosemiquinone ligands at the metal ion forms azenophenolates that are bound to Cu in Cu(py). The Cu(Cat-N-SQ) subunits play a major role in the synthesis of extended polymers with cooperative ferromagnetic properties. N-N bonds are detected after the condensation of trihydroxyphenylalanine.

Spectroscopic and crystallographic studies of iminosemiquinone complexes of copper indicate that the complexes possess a tetrahedral geometry and that the iminoquinone ligands undergo one-electron oxidation and reduction reactions. An S=1/2 magnetic ground state is observed in the complexes at low temperatures. A ferromagnetic exchange takes place between the phenoxazinolate semiquinone (PhenoxSQ) ligands, while an antiferromagnetic exchange occurs between copper and PhenoxSQ.

Reaction between copper metal and 3,5-di-tert-butyl-1,2-benzoquinone (3, 5-DBBQ) results in the formation of Cu(py)2(3,5-DBCat) and characterization is done in the presence of triphenylphosphte monomeric units attached at basal centers by connecting catecholate oxygen atoms. Charge distribution is controlled by coligand banding effects and quinone ligands and is sensitive to the orbital energy of the metal ion.

The compound (tetramethylethylenediamine)(9,10-phenanthrenequinone) (9, 10-phenanthrenediolato)copper(II), Cu(TMEDA)(PhenCat)(PhenBQ), was prepared by refluxing a solution of copper wire, 9,10-phenanthrenequinone and tetramethylethylenediamine. The Cu(TMEDA)(PhenCat)(PhenBQ) molecule shows a square pyramidal coordination geometry with basal sites determined by the TMEDA and phenanthrenediolate ligands. The 9,10-phenanthrenequinone ligand is bonded to the metal at the apex through one oxygen atom. Crystals of the complex form in the monoclinic crystal system, space group P2(sub 1)/n.

A mild alternative to the conversion of a nitro compound to a ketone is described. Mesitylcopper(I) reacts with 2-nitropropane in the presence of PPh3 to yield the copper(I) aci-2-nitropropanate complex, which, in turn, gives acetone and O,O'-nitritobis(triphenylphosphine)copper(I) upon reaction with triplet dioxygen. This may indicate that the presence of copper(I) is crucial in the activation of triplet dioxygen and that the reduced oxygen species is inclined toward oxidative splitting of the C=N double bond.

The reaction of C6O6.8H2O, copper and N,N,N',N'-tetramethylethylenediamine in acetonitrile was analyzed to characterize the copper-quinone coordination chemistry. Reactions involving metallic copper and triquinoyl octahydrate involved the chelation of oxalate ligands with Cu ions which led to the formation of a linear polymer composed of complex units of [(tmeda)Cu(mu-C5O5)Cu(tmeda)(mu-C2O4)]n. The reaction process was also characterized by the formation of (tmeda)CuI(C6O6.-) during the addition of triquinoyl to metallic copper.