Self-assembly of a chiral phosphinegold(I) building block into a two-dimensional netsheet based on a hydrogen bond between one Cl- anion and three hydroxy groups, co-ordination and aurophilicity interactions†

Abstract

The trigold(I) complex [{Au(mbpa)} ₃ S]Cl 2 [mbpa = methyl 4,6-O-benzylidene-3-deoxy-3-(diphenylphosphino)-α- D-altropyranoside] has been obtained from the compound [Au(mpba)Cl] 1 and L-cysteine. Complex 2 crystallizes in space group P6 ₆ with a = 15.165(2), c = 18.897(3) Å and Z = 2, R = 0.030, R′ = 0.050. The crystal structure shows that the Au ₃ S core is a perfect trigonal pyramid with angles Au–S–Au and P–Au–S of 88.7 and 179.6°, respectively, and that the chiral building blocks [{Au(mpba)} ₃ S] ⁺ assemble through triple hydrogen bonding between one hydrogen-bond acceptor, Cl ^- , and three hydrogen-bond donors [Cl · · · O(2) 3.017(10) Å], and form infinite two-dimensional netsheets. The netsheets align in the same direction. A relativistic interaction of the d ¹⁰ closed shell of gold(I) was revealed by NMR studies. Complex 2 displays a strong bright white emission at 495 nm when excited at 303 nm at room temperature, where the lowest-energy transition is of metal-to-ligand charge-transfer (Au→S) type.