Preparation and crystal structures of trans-bis(imidato)bis(1,2-diphenylethylamine)copper(II) complexes (imidato=5,5-diphenylhydantoinato and succinimidato). Particular boundary cases of coordination geometry and monodentateligand conformation

Two new copper(II) complexes, trans-[Cu(phent)(2)(R-diphenea)(S-diphenea)]. 2CHCl(3) (1) and trans-[Cu(succim)(2)(R-diphenea)(S-diphenea)] (2) (phent = 5,5-diphenylhydantoinate, succim = succinimidate, and diphenea = 1,2-diph enylethylamine) were prepared and crystal structures were determined. Never theless both complexes have the same diphenea ligands, 1 affords a distorte d square planar [CuN4] coordination with imidate and amine trans-N-Cu-N bon d angles 156.6(2) and 161.4(2)degrees, while 2 affords a square planar [CuN 4] coordination with both trans-N-Cu-N bond angle 180.0 degrees. Complex 2 was the first example of square planar [CuN4] complexes with 1-phenyl subst ituted ethylamine derivatives. Structural features are compared among 1, 2, and previously reported distorted square planar trans-[Cu(phent)(2)(R-phen ea)(S-phenea)] (3) and trans-[Cu(succim)(2)(R-phenea)(S-phenea)] (4) (phene a = 1-phenylethylamine) complexes. The structural features suggest that the [CuN4] coordination environment of 1 is distorted by particular edge-to-fa ce arrangement of phenyl groups of amines and imidates which reasonably cor responds to the most and the second stable conformation of diphenea ligands with respect to rotation of two phenyl groups. (C) 2001 Elsevier Science B .V. All rights reserved.