Synthesis and Structures of Oxyanion Encapsulated Copper(I)-dppm Complexes (dppm = Bis(diphenylphosphino)methane)

Abstract

Copper(I)-dppm complexes encapsulating the oxyanions ClO(4)(-), NO(3)(-), CH(3)C(6)H(4)CO(2)(-), SO(4)(2-), and WO(4)(2-) have been synthesized either by reduction of the corresponding Cu(II) salts and treatment with dppm, or by treating the complex [Cu(2)(dppm)(2)(dmcn)(3)](BF(4))(2) (1) (dmcn = dimethyl cyanamide) with the respective anion. The isolated complexes [Cu(2)(dppm)(2)(dmcn)(2)(ClO(4))] (ClO(4)) (2), [Cu(2)(dppm)(2)(dmcn)(2)(NO(3))] (NO(3)) (3), Cu(2)(dppm)(2)(NO(3))(2) (4), [Cu(2)(dppm)(2)(CH(3)C(6)H(4)CO(2))(2)]dmcn.2THF (5), Cu(2)(dppm)(2)(SO(4)) (6), and [Cu(3)(dppm)(3)(Cl)(WO(4))] 0.5H(2)O (7) have been characterized by IR, (1)H and (31)P{(1)H} NMR, UV-vis, and emission spectroscopy. The solid-state molecular structure of complexes 1, 2, 4, and 7 were determined by single-crystal X-ray diffraction. Pertinent crystal data are as follows: for 1, monoclinic P2(1)/c, a = 11.376(10) Å, b = 42.503(7) Å, c = 13.530(6) Å, beta = 108.08(2) degrees, V = 6219(3) Å(3), Z = 4; for 2, monoclinic P2(1)/n, a = 21.600(3) Å, b = 12.968(3) Å, c = 23.050(3) Å, beta = 115.97(2) degrees, V = 5804(17) Å(3), Z = 4; for 4, triclinic P&onemacr;, a = 10.560(4) Å, b = 10.553(3) Å, c = 22.698(3) Å, alpha = 96.08(2) degrees, beta = 96.03(2) degrees, gamma = 108.31(2) degrees, V = 2362(12) Å(3), Z = 2; and for 7, orthorhombic P2(1)2(1)2(1), a = 14.407(4) Å, b = 20.573(7) Å, c = 24.176(6) Å, V = 7166(4) Å(3), Z = 4. Analyses of the crystallographic and spectroscopic data of these complexes reveal the nature of interactions between the Cu(I)-dppm core and oxyanion. The anchoring of the oxyanion to the Cu(n)()(dppm)(n)() unit is primarily through coordination to the metal, but the noncovalent C-H.O interactions between the methylene and phenyl protons of the dppm and oxygen atoms of the oxyanion play a significant role. The solid-state emission spectra for complexes 1-6 are very similar but different from 7. In CDCl(3) solution, addition of ClO(4)(-) or NO(3)(-) (as their tetrabutylammonium salts) to 1 establishes a rapid equilibrium between the anion-complexed and uncomplexed forms. The association constant values for ClO(4)(-) and NO(3)(-) have been estimated from the (31)P{(1)H} NMR spectra.