Metal-phosphine chalcogenide interactions. Crystal and molecular structures of [di-mu-iodo-bis{(methyl cyanide-N)(triphenylthiophosphorane-S)copper(I)}] and [di-mu-chloro-bis{mu-1,2-ethylenebis(diphenylphosphine selenide-Se,Se)} dicopper(I)]

Complexes of Cu-I with tertiary phosphine chalcogenides are described. CuI reacts with Ph3PS in MeCN/CH2Cl2 to form {CuI(Ph3PS)(MeCN)} and CuCl reacts with 1,2-ethylene-bis(tertiary phosphine selenide) {dpeSe(2)} in MeCN to y ield {CuCl(dpeSe(2))}. Both compounds exist as halogen-bridged centrosymmet ric dimers: [Cu-2(mu -I)(2)-(Ph3PS)(2)(MeCN)(2)] (1) and [Cu-2(mu -Cl)(2)(d peSe(2))(2)] (2) respectively. Compound (1) has almost symmetric Cu-I bonds , d(Cu-I) = 2.6503(8) Angstrom and d(Cu-I') = 2.7196(9) Angstrom, and each Cu is further bonded to a S atom [d(Cu-S) = 2.3444(13) Angstrom] from Ph3PS and to a N atom [d(Cu-N) = 2.030(5) Angstrom] from MeCN. Compound (2) has unequal Cu-Cl bonds, 2.6390(19) and 2.2806(18) Angstrom and nearly equal Cu -Se bonds [2.4042(11) and 2.4060(11) Angstrom]. The geometry about each Cu center in both cases is distorted tetrahedral. The Cu-Cu bond distance in ( 2) is 3.249(2) Angstrom as compared with 3.4141(16) Angstrom in (1). MeCN i s bonded strongly to Cu-I as the excess of Ph3PS failed to remove it from t he coordination sphere. Compound (2) represents the first structurally char acterised example of copper(I) with a bis(tertiary phosphine selenide) (dpe Se(2)) acting as a bridging ligand.