Stabilisation of three coordinate Cu(I) a theoretical and experimental study

COPPER COORDINATION CHEMISTRY: POSTERS 57 P37 SYNTHESIS, SPKrRA, REDOX I~IONS AND CATJK8OJASE ACl’IVITp OF coppBR( II) m OF CERl’AIN TRIIQI&%LIGBNDS. UmaandMallayanPalaniandavar, Dept. of cliemistry, Bharathidasan University, Tiruchirapalli- 620 024. Tamilnadtl. INDIA Copper complexes of tripodal 1 igands containing benzimidazole and/or pyridine and one or two phenolic hydroxyl groups have been isolated. The electronic and EPR spectral studies reveal a square pyramidal geometry for these complexes. The crystal structure of one of the complexes reveal an unusual axial coordination of phenolate olrygen in a square pyramidal environment. The pyridyl complexes exhibit El/ 1 values more positive than the benzimidazolyl ones. The react vity of the complexes as catalysts for the aerobic oxidation of catechol to quinone has been studied spectrophotometrically. ~38 HUMAN DBH CDNA EXPRESSION IN E. COLZ AND SACCHAROMYCES CEREVZSZAE. &I. R6w1, J. Kessl 1, M. Pierrot 1, J. C. Chaix 2, X-J Guo 2, A. Lamouroux 3 and J. Mallet 3. 1 L. B. S. URA CNRS 1409; 2 B. B. M. C., Universitt! d’Aix-Marseille III, Facultb des Sciences de St. J&6me, F13397 Marseille Ct!akx 13; 3 L. N. M. C. UPR CNRS 23, Traverse de la Terrasse, F91190 Gif SW Yvette. Dopamine-p-hydroxylase (DBH) is a copper containing monooxygenase which converts dopamine into noradrenaline. As the exact nature of the copper site is not well understood we have undertaken a structural study including directed mutagenesis. We will describe here the first step of this work: human DBH cDNA 1 in E. coli and Saccharomyces cerevisiae using various expression plasmids. 1. A. Lamouroux, A. Vigny, N. Faucon Biguet, M. C. Darmon, R. Franck, J. P. Henry and J. Mallet, EMBO J., 13, 3931, (1987). P39 STABILISATION OF THREE COORDINATE Cu(1) A THEORETICAL AND EXPERIMENTAL STUDY Claire Russella, Peter Hubbersteya, Paul Walton,a Odile Eisensteinb, Sarah Jackson,b aNottingham University , Nottingham, NG7 2RD, UK, bLaboratoire de Chimie Theorique, Universite de Paris -Sud, 91405, Orsay, France. Deoxyhaemocyanin contains two 3-coordinate planar Cu(I) atoms in its active site. Using EHMO calculations we have studied the coordination of diverse ligands to Cu(I) and have shown that ligands which act as x-acceptors in the LUMO (eg, CN-, NCR) are most effective in stabilising 3-coordinate Cu(1). Using cyanoguanidine (cnge) and pyridazine (pz) we have synthesised [Cu$+(cnge)], [Cu2(cnge)d2+ and [Cu&z)2(cnge)2]2+; all three contain 3- coordinate planar Cu(1) atoms, the lattertwo in a binuclear system.

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Transcript of Stabilisation of three coordinate Cu(I) a theoretical and experimental study

Page 1: Stabilisation of three coordinate Cu(I) a theoretical and experimental study

COPPER COORDINATION CHEMISTRY: POSTERS 57

P37 SYNTHESIS, SPKrRA, REDOX I~IONS AND CATJK8OJASE ACl’IVITp OF coppBR( II) m OF CERl’AIN TRIIQI&% LIGBNDS. UmaandMallayanPalaniandavar,

Dept. of cliemistry, Bharathidasan University, Tiruchirapalli- 620 024. Tamilnadtl. INDIA

Copper complexes of tripodal 1 igands containing benzimidazole and/or pyridine and one or two phenolic hydroxyl groups have been isolated. The electronic and EPR spectral studies reveal a square pyramidal geometry for these complexes. The crystal structure of one of the complexes reveal an unusual axial coordination of phenolate olrygen in a square pyramidal environment. The pyridyl complexes exhibit El/

1 values more positive than the

benzimidazolyl ones. The react vity of the complexes as catalysts for the aerobic oxidation of catechol to quinone has been studied spectrophotometrically.

~38 HUMAN DBH CDNA EXPRESSION IN E. COLZ AND SACCHAROMYCES CEREVZSZAE. &I. R6w1, J. Kessl 1,

M. Pierrot 1, J. C. Chaix 2, X-J Guo 2, A. Lamouroux 3 and J. Mallet 3. 1 L. B. S. URA CNRS 1409; 2 B. B. M. C., Universitt! d’Aix-Marseille III, Facultb des Sciences de St. J&6me, F13397 Marseille Ct!akx 13; 3 L. N. M. C. UPR CNRS 23, Traverse de la Terrasse, F91190 Gif SW Yvette.

Dopamine-p-hydroxylase (DBH) is a copper containing monooxygenase which converts dopamine into noradrenaline. As the exact nature of the copper site is not well understood we have undertaken a structural study including directed mutagenesis. We will describe here the first step of this work: human DBH cDNA 1 in E. coli and Saccharomyces cerevisiae using various expression plasmids. 1. A. Lamouroux, A. Vigny, N. Faucon Biguet, M. C. Darmon, R. Franck, J. P. Henry and J. Mallet, EMBO J., 13, 3931, (1987).

P39 STABILISATION OF THREE COORDINATE Cu(1) A THEORETICAL AND EXPERIMENTAL STUDY

Claire Russella, Peter Hubbersteya, Paul Walton,a Odile Eisensteinb, Sarah

Jackson,b aNottingham University , Nottingham, NG7 2RD, UK, bLaboratoire de Chimie Theorique, Universite de Paris -Sud, 91405, Orsay, France.

Deoxyhaemocyanin contains two 3-coordinate planar Cu(I) atoms in its active site. Using EHMO calculations we have studied the coordination of diverse

ligands to Cu(I) and have shown that ligands which act as x-acceptors in the

LUMO (eg, CN-, NCR) are most effective in stabilising 3-coordinate Cu(1). Using cyanoguanidine (cnge) and pyridazine (pz) we have synthesised [Cu$+(cnge)], [Cu2(cnge)d2+ and [Cu&z)2(cnge)2]2+; all three contain 3- coordinate planar Cu(1) atoms, the latter two in a binuclear system.