Structural Determinations of Four Mono- and Binuclear Tertiary Phosphine and Arsine Complexes of Copper(I) Chloride

Abstract

The structure of [(C6H5)3CuCl has been determined by x-ray diffraction. The compound crystallizes in the trigonal space group P3, with unit cell dimensions a = 19.2775 (14) Å and c = 10.4720 (9) Å, and Z = 3. A crystallographic threefold rotation axis passes through the Cu-Cl bond. Some important bond distances and angles are Cu-Cl(av) = 2.34 (2) Å, Cu-P(av) = 2.351 (4) Å, Cl-Cu-P(av) = 109.1 (7)°, and P-Cu-P(av) = 109.8 (7)°. The compound [(C6-H5)2(CH3)P]3CuCl crystallizes in the orthorhombic space group Pn21a, with Z = 4 and cell constants a = 20.229 (14) Å, b = 17.180 (10) Å, and c = 10.309 (5) Å. The molecular geometry is approximately tetrahedral. The rotational conformation about the three Cu-P bonds creates a sterically favorable pocket for the chlorine atom. Some distances and angles are Cu-Cl = 2.366 (4) Å, Cu-P(av) = 2.289 (6) Å, Cl-Cu-P(av) = 103 (2)°, and P-Cu-P = 108.3 (1), 117.7 (1), 118.1 (1)°. The compound {[(C6H5)(CH3)2As]2CuCl}2 crystallizes in the monoclinic space group P21/n, with unit cell parameters a = 9.888 (3) Å, b = 17.082 (5) Å, c = 11.277 (6) Å, and β = 94.11 (2)°, and Z = 2 (dimers). The molecule is a dichloride-bridged dimer having two pseudotetrahedral copper atoms related by an inversion center. Selected distances and angles are Cu-Cl(av) = 2.380 (6) Å, Cu-As(av) = 2,36 (1) Å, As-Cu-As = 118.00 (9)°, Cl-Cu-Cl = 100.9 (1)°, and Cl-Cu-As = 100.7 (1), 105.3 (1), 115.1 (1), 115.8 (1)°. Finally, [(C6H5)3P]3Cu2Cl2-C6H6 is triclinic, space group P, with cell constants a = 12.307 (5) Å, b = 18.722 (9) Å, c = 13.574 (5) Å, α = 117.174 (13)°, β = 73.794 (6)°, and γ = 107.554 (12)°, and Z = 2. Each molecule contains the di-μ-chloro-dicopper(I) core with two triphenylphosphine ligands bonded to one copper atom and one triphenylphosphine ligand bonded to the other copper atom. The result is a binuclear compound containing both three- and pseudotetrahedral four-coordinate copper. The mean copper-chlorine distance of 2.46 (2) Å and copper-phosphorus distance of 2.260 (5) Å in the latter are significantly longer than the respective values of 2.28 (2) and 2.183 (3) Å in the former. Selected interbond angles are Cl-Cu-P(trig) = 123.63 (9), 134.74 (8)°, Cl-Cu-Cl(trig) = 101.63 (9)°, P-Cu-P(tet) = 130.40 (8)°, Cl-Cu-Cl(tet) = 91.57 (8)°, and Cu-Cl-Cu(av) = 82.9 (2)°. Geometries of the four compounds are discussed in detail and compared to those of other Lm(CuX)n complexes, where L = tertiary phosphine or arsine and X = coordinating anion. © 1976, American Chemical Society. All rights reserved.