Preparation and Electrochemical Behaviour of Dinuclear Platinum Complexes Containing NCN Ligands (NCN + [C6H3(Me2NCH2)2-2,6]-). The Crystal Structure of [C2H2(Me2NCH2)2-1,3-(CMC)-5]2

A series of homodinuclear Pt compounds containing the anionic, potentially terdentate NCN ligand (NCN=[C{6}H{3}(Me{2}NCH{2}){2}-2, 6]}-{) or its 4-ethynyl derivative were prepared. The two platinum centres are linked together in two different fashions: (i) directly linked by an ethynyl or diethynylphenyl group (head-to-head) and (ii) indirectly bonded by a ethynyl- or butadiynyl-linked bis-NCN ligand (tail-to-tail). The reaction of the head-to-head @s,@s'-ethynylide complex {Pt}C@8C{Pt} ({Pt}=[Pt(C{6}H{3}{CH{2}NMe{2}}{2}-2,6)]}+{) with [CuCl]{n} yields {Pt}Cl and [Cu{2}C{2}]{n}, while with [Cu(NCMe){4}][BF{4}] a Cu(I) bridged complex was formed: [(@h}2{-{Pt}C@8C{Pt}){2}Cu][BF{4}]. The results of cyclic voltammetry experiments reveal that both connection modes of the two platinum centres lead to electrochemically independent Pt-NCN units. The X-ray crystal structure analysis of the neutral, tail-to-tail bridging butadiyne bis-NCNH ligand [C{6}H{3}(CH{2}NMe{2})-1,3-(C@8C)-5]{2} is reported