Metal π-complexes of cyclooctatetraenes. V. Synthesis and x-ray analysis of tetrameric dibenzo[a,e]cyclooctatetraenecopper(1) chloride, a new "step" configuration for the Cu 4Cl 4 ring

Abstract

Tetrameric dibenzo[a,e]cyclooctatetraenecopper(I), 3 3 IUPAC name: cyclotetra-μ-chlorotetrakis[9-10:11-12-η-dibenzo[a,e]cyclooctenecopper(I)] [2]. [(C 16H 12)CuCl] 4, 1, has been synthesized and characterized by X-ray crystallography. Complex 1 crystallizes in space group P1 with a 9.287(7), b 10.818(7), c 13.234(5) Å, α 91.34(4), β 103.44(4), γ 95.20(5)°, V 1287(1) Å 3, and Z = 1. The structure has been refined to R F= 0.063 and R wF= 0.078 for 3286 observed Mo-K α data and 325 variables. The cyclic molecule, which has crystallographically imposed 1 symmetry, consists of an eight-membered ring of alternating Cu and Cl atoms in a "step" (or "chair") configuration, with an organic ligand π-bonded to each metal center via a pair of olefinic double bonds. The two symmetry-independent copper(I) atoms are in distorted trigonal pyramidal coordination, each being bound asymmetrically to chloride and olefin ligands at distances in the ranges 2.263(2)-2.278(2) and 2.099(5)-2.801(6) Å, respectively. © 1983.