Exploration on Au(S–4-py)PR3 complexes as a viable building block for constructing hetero-nuclear supramolecules: synthesis and X-ray study on M(acac′)2[Au(S–4-py)PR3]2(ClO4)x (M = Cr, Cu; acac′ = acetylacetonate, hexafluoro-acetylacetonate; x = 0 or 1)

Transition metal acetylacetonates, M(acac′)2(ClO4)x (M = Cr, Cu; acac′ = acetylacetonate, hexafluoro-acetylacetonate; x = 0 or 1) were reacted as a scaffolding for constructing a hetero metallic supra molecule with Au(S–4-py)L (L = PPh3, PPh2(2-py)) as a ligand. A trimetallic monomer, Au–Cr–Au, 5 was yielded from [Cr(acac)2(H2O)2]ClO4. However, [Cu(hfac)2] yielded a dimer 6 composed of a trimetallic monomer (Au–Cu–Au) moiety and an infinite chain polymer(⋯Au–Cu–Au⋯Au–Cu–Au⋯) 7 by virtue of aurophilicity in the solid state, the higher order structure of which depends on the co-existing ligand L. Basic structures of 6 and 7 are affected by L; 6 has a cis geometry, while 7 a trans geometry. Cooperative effect of the steric bulkiness of L and aurophilicity is presumed to determine the geometry.