Synthesis and structures of oxyanion encapsulated copper(I)-dppm complexes(dppm = bis(diphenylphosphino)methane)

Copper(I)-dppm complexes encapsulating the oxyanions ClO4-, NO3-, CH3C6H4CO 2-, SO42-, and WO42- have been synthesized either by reduction of the corre sponding Cu(II) salts and treatment with dppm, or by treating the complex [ Cu-2(dppm)(2)(dmcn)(3)](BF4)(2) (1) (dmcn = dimethyl cyanamide) with the re spective anion. The isolated complexes [Cu-2(dppm)(2)(dmcn)(2)(ClO4)] (ClO4 ) (2), [Cu-2(dppm)(2)(dmcn)(2)(NO3)] (NO3) (3), Cu-2(dppm)(2)(NO3)(2) (4), [Cu-2(dppm)(2)(CH3C6H4CO2)(2)]dmcn.2THF (5), Cu-2(dppm)(2)(SO4) (6), and [C u-3(dppm)(3)(Cl)(WO4)] 0.5H(2)O (7) have been characterized by IR, H-1 and P-31{H-1} 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 P 2(1)/c, a = 11.376(10) Angstrom, b = 42.503(7) Angstrom, c = 13.530(6) Angs trom, beta = 108.08(2)degrees, V = 6219(3) Angstrom(3), Z = 4; for 2, monoc linic P2(1)/c, a = 21.600(3) Angstrom, b = 12.968(3) Angstrom, c = 23.050(3 ) Angstrom, beta = 115.97(2)degrees, V = 5804(17) Angstrom(3), Z = 4; for 4 , triclinic <P(1)over bar>, a = 10.560(4) Angstrom, b = 10.553(3) Angstrom, c = 22.698(3) Angstrom, alpha = 96.08(2)degrees, beta = 96.03(2)degrees, g amma = 108.31(2)degrees, V = 2362(12) Angstrom(3), Z = 2; and for 7, orthor hombic P2(1)2(1)2(1), a = 14.407(4) Angstrom, b = 20.573(7) Angstrom, c = 2 4.176(6) Angstrom, V = 7166(4) Angstrom(3), Z = 4. Analyses of the crystall ographic and spectroscopic data of these complexes reveal the nature of int eractions between the Cu-I-dppm core and oxyanion. The anchoring of the oxy anion to the Cu-n(dppm)(n) unit is primarily through coordination to the me tal, but the noncovalent C-H ... O interactions between the methylene and p henyl protons of the dppm and oxygen atoms of the oxyanion play a significa nt role. The solid-state emission spectra for complexes 1-6 are very simila r but different from 7. In CDCl3 solution, addition of ClO4- or NO3- (as th eir tetrabutylammonium salts) to 1 establishes a rapid equilibrium between the anion-complexed and uncomplexed forms. The association constant values for ClO4- and NO3- have been estimated from the P-31{H-1} NMR spectra.