Cobalt(III) complexes with linear hexadentate N-6 or N4S2 donor set atoms providing pyridyl-amide-amine/thioether coordination

摘要

Two new cobalt(III) complexes of symmetric hexadentate ligand with N-6 [1,10-bis(2-picolinamide)-4,7-diazadecane (pycdpnen)] and N4S2 [1,8-bis(2-picolinamide)-3,6-dithiaoctane (pycdadt)] donor set atoms have been synthesized as perchlorate salts and characterized by spectroscopic methods. All two ligands with strong-field pyridylcarboxamido N donor stabilize Co(III) as demonstrated by the facile oxidation of the cobalt center. The structures of [Co(pycdpnenH(-2))](ClO4) (1) and [Co(pycdadtH(-2))]ClO4) center dot H2O (2) investigated by COSY, HMBC, HMQC and NOESY NMR studies show that compounds 1 and 2 have the same geometrical configuration. The X-ray analysis reveals that complex 2 crystallizes in a orthorhombic space group Pccn. The cation [Co(pycdadtH(-2))](+) is distorted octahedral with the two pyridyl groups in cis position. (c) 2006 Elsevier B.V. All rights reserved.