Mono and bimetallic CoIII Schiff base complexes: Coordination induced ligand imidazolidine ring cleavage and stabilization
作者:Supriti Paul、Wing-Tak Wong、Debashis Ray
DOI:10.1016/j.ica.2011.03.058
日期:2011.6
2-(2'-Hydroxyphenyl) imidazoline ring grafted dinucleating diimine-diamine-tris-phenol ligand (H(3)aeas) has been obtained from a two-step reaction of 2-hydroxy acetophenone, N,N'-bis-(2-aminoethyl)ethylenediamine and 2-hydroxy benzaldehyde. Reaction of the ligand with Co(ClO4)(2)center dot 6H(2)O and NEt3 in MeOH-DCM solvent mixture yielded the monometallic complex [Co(aea)]ClO4 center dot H2O (1) of imidazolidine ring hydrolyzed hexadentate proligand H(2)aea. Any solvent derived MeO bridged Co-2 complex could not be obtained due to facile cobalt coordination assisted hydrolytic cleavage of substituted imidazolidine ring. When the reaction is carried out with Co(NO3)(2)center dot 4H(2)O and CoCl2 center dot 6H(2)O in presence of NH4NCS and NaN3 in MeOH-DCM and MeOH under aerobic conditions, preassembly of bimetallic [Co-2(mu-OMe)](5+) and [Co-2(mu-N-3)](5+) cores takes place on the solvent derived methoxido and azido clips through non-hydrolytic pathways in [(SCN)(2)Co-2(mu-OMe)(mu-aeas)]center dot DMF (2), and cocrystals of [(N-3)(2)Co-2(mu-OMe)(mu-aeas)] (3a) and [(N-3)(2)Co-2(mu-N-3)(mu-aeas)] (3b), respectively. Crown Copyright (C) 2011 Published by Elsevier B. V. All rights reserved.