Crystal structures of a series of Co-II, Cu-II and Zn-II complexes of 4 '-(3,4-dihydroxyphenyl)-2,2 ': 6 ',2 ''-terpyridine and 4 '-(3,4-dimethoxyphenyl)-2,2 ': 6 ',2 ''-terpypidine

摘要

The crystal structures of the bis(terpyridyl)-metal(II) complexes [Co(L-1)(2)][PF6](2) . 2.5MeCN, [Co(L-2)(2)][PF6](2) . 3dmf, [Cu(L-2)(2)][PF6](2) . MeCN, [Zn(L-1)(2)][PF6](2) . 2.5MeCN, and [Zn(L-2)(2)][NO3](2) . 3dmf are reported, where L-1 is 4'-(3,4-dihydroxyphenyl)-2,2':6',2 "-terpyridine and L-2 is 4'-(3,4-dimethoxyphenyl)-2,2':6',2 "-terpyridine. The two Co-II complexes and the Cu-II complex all show elongation along one axis in addition to the normal tetragonal compression imposed by terpyridyl chelates; this is ascribed to the Jahn-Teller effect, in the case of the Co-II complexes arising from the presence of a significant proportion of the low-spin state being present at the temperature used for the structural determination (173 K). The Zn-II complexes are the first structurally characterised bis(terpyridyl)-Zn-II compounds. These do not show the elongation along one axis that was apparent in the Co-II and Cu-II structures. The relatively small bite angles for the terpyridyl chelates (ca. 150 degrees, compared to ca. 160 degrees for the first three complexes), results in a greater distortion away from regular octahedral geometry, reflecting the absence of stereoelectronic requirements for Zn-II compared to Co-II and Co-II. (C) 1997 Elsevier Science Ltd. [References: 23]