An investigation of Cu(II) and Ni(II)-catalysed hydrolysis of (di)imines
Artikel i vetenskaplig tidskrift, 2010

The reactions of six diimine ligands with Cu(II) and Ni(II) halide salts have been investigated. The diimine ligands were Ph2C=N(CH2)(n)NC=Ph-2 (n = 2 (Bz(2)en, 1a), 3 (Bz(2)pn, 1b), 4 (Bz2bn, 1c)), N, N'-bis-(2-tert-butylthio- 1-ylmethylenebenzene)-2,2'diamino-biphenyl (2), N,N'-bis-(2-chloro-1-ylmethylenebenzene)-1,3diaminobenzene (3) and N,N'-bis-(2-chloro-1-ylmethylenebenzene)-1,2-ethanediamine (4). Reactions of 1a-c, 2-4 with CuCl2 center dot 2H(2)O in dry ethanol at ambient temperature led to complete or partial hydrolysis of the diimine ligands to ultimately form copper diamine complexes. The non-hydrolyzed complexes of 1b and 1c, [Cu(L)Cl-2] (L = 1b, 1c), could be isolated when the reactions were carried out at low temperatures, and the half-hydrolyzed complex [Cu(Bzpn)Cl-2] could also be identified via X-ray crystallography. Similarly, reactions of 1a or 1b with NiCl2 center dot 6H(2)O or [NiBr2(dme)] led to rapid hydrolysis of the imines and Ni complexes containing half-hydrolyzed 1a (Bzen; [trans-[Ni(Bzen)(2)Br-2]) and 1b (Bzpn; [Ni(Bzpn) Br-2] could be isolated and identified via single crystal X-ray analysis. Kinetic studies were made of the hydrolyses of 1a, 1b in THF and 2 in acetone, in the presence of Cu(II), and of 1a in acetonitrile, in the presence of Ni(II). Activation parameters were determined for the latter reaction and for the copper-catalyzed hydrolysis of 2; the relatively large negative activation entropies clearly indicate rate-determining steps of an associative nature.




copper(ii) complexes








M. Czaun

Lunds universitet

University of Southern California

S. M. Nelana

Vaal University of Technology

University of Johannesburg

I. A. Guzei

University of Wisconsin Madison

Catrin Hasselgren

Chalmers, Kemi- och bioteknik

M. Hakansson

Göteborgs universitet

Susan Elisabeth Jagner

Chalmers, Kemi- och bioteknik

G. Lisensky

Beloit College

J. Darkwa

University of Johannesburg

E. Nordlander

Lunds universitet

Inorganica Chimica Acta

0020-1693 (ISSN)

Vol. 363 12 3102-3112