Lewis-Base Adducts of Group 11 Metal(I) Compounds. LI. Synthesis and Structural Characterization of Mononuclear Chloro-, Bromo- and Iodo-pyridinebis(triphenylphosphine)copper(I) Complexes

Abstract

Complexes [ XCu ( py )(PPh₃)₂], X = Cl, Br, I, py = pyridine, have been synthesized and characterized by single-crystal X-ray structure determination. Chloride and iodide derivatives have similar cells [ isomorphous (?) but not isostructural ], triclinic, pi, a = 19.5 A, b = 10.5, c = 9.6 Å , α ≈ 66, β ≈ 86, γ ≈ 83º, Z = 2; the bromide is monoclinic, Cc, a 13.568(9), b 15.760(12), c 16.545(8) Å , β 95.65(5)º, Z = 4. Cl, Br, I structures were refined to residuals of 0.042, 0.055, 0.039 for 4288, 2241, 4808 'observed' reflections. In all cases, the copper atom is four-coordinate; for such an array, Cu-X lengths are unusually short [2.318(2), 2.459(2), 2.636(1) Å (Cl, Br, I) and Cu-N unusually long (2.14(1) Å ], while (Cu-P) increase from 2.26₄ to 2.28₈ Å across the series. The dominant aspect of the complexes is thus that of XCu (PPh₃)₂ solvated by pyridine.