A new type of dicopper structure with side arm coordinating triarylphosphane ligands

Treatment of P(C6H4CH2NMe2-2)3 (1) with 2 equiv. of CuX (2a X=Cl, 2b X=Br) produces the novel dicopper complexes [P(C6H4CH2NMe2-2)3]Cu2X2 (3a X=Cl, 3b X=Br) in high yields. The X-ray structure of 3b was determined. Crystals of 3b are orthorhombic, space group Pna21, with a=19.280(4) Å, b=15.717(3) Å, c=11.201(2) Å, V=3394(1) Å3, Z=4, and final R1=0.0573 [I≥2σ(I)] for 2301 reflections used (1621 reflection with I≥2σ(I)) and 340 variables. The structure of 3b consists of two copper(I) centers of which one copper atom possesses a heavily distorted trigonal-pyramidal environment, while the other one is almost square-pyramidal coordinated; the Cu2Br2 segment gives rise to a situation, which may be considered as a contact ion pair between Cu+ and CuBr2 −.