Crystal structure of [HgAg(C4H6NO)2(NO3)]2: A dimeric heterometallic complex containing both bi- and trinucleating 2-pyrrolidinone anion ligands and a folded ring

Abstract

Reaction of mercuric acetate, 2-pyrrolidinone and silver nitrate leads to the formation of a dimeric mixed-metal complex, [HgAg(C 4 H 6 NO) 2 (NO 3 )] 2 (where C 4 H 6 NO is the anion of 2-pyrrolidinone). The complex has been characterized by X-ray diffraction; the crystals are orthorhombic, Pbcn , a = 15.532(3), b = 16.244(2), c = 19.755(2) Å, Z = 8. The structure was refined on 2549 reflections to R = 0.054. The dimeric complex has at its centre a folded Ag 2 O 2 ring with the bridging oxygen atoms being provided by the 2-pyrrolidinone anions, the first example of this compound functioning as a trinucleating ligand. There are also significant inter-dimer interactions, giving rise to unusually distorted silver coordination geometries. Further, weak electrostatic, anion-mediated interactions serve to bridge adjacent dimers so as to form loosely linked polymeric sheets.