Group 1B organometallic chemistry XXVII. Complex forming reactions of polynuclear arylcopper compounds; Calk-P bond cleavage in 1,2-bis(diphenylphosphino)ethane (Diphos) by (2-Me2NCH2C6H4)4Cu4 and crystal structure of [(C6H5)2PCu.Diphos]2 -C6H6

Abstract

Molecular weight measurements and microwave titrations indicate that no interaction occurs between tetrameric 2-Me{2}NCH{2}C{6}H{4}Cu (Ar{4}Cu{4}) and the monodentate ligands PPh{3}, CH{3}CN or pyridine. However, the tetrameric structure Ar{4}Cu{4} breaks down upon interaction (1/1 molar ratio ArCu/L) with the bidentate ligands (L) Diphos or cis-DPPEE to give the monomeric 1/1 complexes ArCu . L.Addition of Diphos to ArCu . Diphos or conducting the reaction of Ar{4}Cu{4} with Diphos in a 1/2 ratio (ArCu/Diphos) gives rise to a C{a}{l}{k}@?P bond cleavage reaction resulting in the formation of dimeric (Ph{2}PCu . Diphos){2} . 2 C{6}H{6}, ArH and Ph{2}PCH@?CH{2}.The molecular structure of (Ph{2}PCu . Diphos){2} . 2 C{6}H{6}, has been determined by a single-crystal X-ray diffraction study. Crystals are monoclinic, space group P2{1}/c and have Z @? 2 in a unit cell of dimensions a @? 12.997(6), b @? 12.669(7), c @? 22.839(9) @9 and @b @? 94.48(4)}o{. The structure was refined to R @? 0.048 for 3048 independent reflections. The four copper atoms in the dimer are held together by two Ph{2}P bridges. The bonding in the dimer is discussed.