Synthesis, structure and catecholase activity of dinuclear copper and zinc complexes with an N(3)-ligand.
The preparation and characterization of dinuclear [M(II)(dbcat)(idpa)](2) (M[double bond]Zn (1), Cu (3); dbcat[double bond]3,5-di-tert-butylcatecholate; idpa[double bond]3,3'-iminobis(N,N-dimethylpropylamine)) complexes are described. Crystallographic characterization of the complex [Cu(II)(dbcat)(idpa)](2) has shown that the co-ordination geometry around copper(II) ions is distorted square pyramidal (triclinic, P-1, a=10.576(1) A, b=11.927(1) A, c=12.621(1) A, alpha=77.89(1) degrees, beta=88.65(1) degrees, gamma=70.21(1) degrees, V=1462.7(2) A(3), Z=2, R=0.0387). Both 1 and 3 were suitable catalysts for the catalytic oxidation of dbcatH(2) to dtbq (dtbq=3,5-di-tert-butyl-1,2-benzoquinone) with dioxygen at ambient conditions in good yields. However, on the basis of kinetic studies the copper- and zinc-catalyzed reactions showed different mechanisms. In the first case valence tautomerism [Cu(II)(dbcat)(idpa)]<==>[Cu(I)(dbsq)(idpa)] precedes the reaction with O(2), while with the zinc complex metal-bound catecholate reacts directly with O(2) with the formation of free superoxide anion.
Research Group for Petrochemistry, Hungarian Academy of Sciences, 8201 Veszprém, Hungary.
József
J
Kaizer
József
J
Pap
Gábor
G
Speier
László
L
Párkányi
László
L
Korecz
Antal
A
Rockenbauer
D002396:Catechols / Q000737:chemistry* / Q000378:metabolism; D003300:Copper / Q000737:chemistry*; D018360:Crystallography, X-Ray; D004578:Electron Spin Resonance Spectroscopy; D015394:Molecular Structure; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000737:chemistry* / Q000378:metabolism; D012996:Solutions; D015032:Zinc / Q000737:chemistry*
D002396:Catechols; D012996:Solutions; D003300:Copper; D010088:Oxidoreductases; D015032:Zinc