Guanidinates as chelating anionic ligands for early, middle and late transition metals: syntheses and crystal structures of [Ti{eta(2)-(NPh)(2)CNEt2}(2)Cl-2], [Ru{eta(2)-(NPh)(2)CNHPh}(3)] and [Pt{eta(2)-(NPh)(2)CNHPh}(2)]

摘要

Treatment of the dimeric ruthenium halide complex [Ru(eta-C6H6)Cl-2](2) with 1,2,3-triphenylguanidine provided the tris-chelate [Ru{eta(2)-(NPh)(2)CNHPh}(3)] with loss of the aromatic ligand and metal oxidation. This product may also be prepared by treatment of the previously reported [Ru(eta-p-(PrC6H4Me)-C-i){eta(2)-(NPh)(2)CNHPh}Cl] with bases (KOH, (LiNPr2)-Pr-i, NEt3). Complexes containing chelating guanidinate ligands are also available by means of metathesis of the monolithiated ligands Li[C(NR)(2)NR2] with metal halide complexes, as exemplified by the synthesis of the square planar bis-chelate [Pt{eta(2)-(NPh)(2)CNHPh}(2)] from [Pt(PhCN)(2)Cl-2] and [Ti{eta(2)-(NPh)(2)CN(Et)(2)}(2)Cl-2] from [TiCl4(THF)(2)]. The characterisation of these complexes allows a comparison of the co-ordination properties of chelating guanidinates with early, middle and late transition metals. [References: 34]