Organogold(I) macrocycles and [2]catenanes containing pyridyl and bipyridyl substituents - Organometallic catenanes as ligands

The synthesis of achiral gold(I) macrocycles [RCH(4-C6H4OCH2CCAu)(2)(mu-Ph(2)PZPPh(2))] and the corresponding chiral gold(I) [2]catenanes, bearing substituents R = 2-pyridyl, 4-pyridyl, and 4-(2,2'-bipyridyl), is reported. The gold(I) compounds form by self-assembly on reaction of oligomeric digold(I) diacetylides [{RCH(4-C6H4OCH2CCAu)(2)}(n)] or the isocyanide complexes [RCH(4-C6H4OCH2CCAuCN-t-Bu)(2)] with diphosphine ligands Ph(2)PZPPh(2), Z = CC or (CH2)(n) with n = 2-5, or on reaction of [Au-2(O2CCF3)(2)(mu-Ph(2)PZPPh(2))] with diacetylenes RCH(4-C6H4OCH2CCH)(2) in the presence of a base. The equilibrium between macrocycles and chiral [2]catenanes in solution was established by NMR spectroscopy, while the structures of several [2]catenanes in the solid state were established crystallographically. The coordination of the gold(I) compounds with R = 4-(2,2'-bipyridyl) to platinum(IV), by formation of the corresponding [PtIMe3(bipy)] units, is established, showing that organometallic [2]catenanes can act as ligands.