Preparation and Crystal Structures of the Urea Adducts of Silver(I) Perchlorate and Silver(I) p-Toluenesulfonate

Abstract

The urea adducts with silver(I) perchlorate (2 : 1) (1) and silver(I) p-toluenesulfonate (1 : 1) (2) have been prepared and their structures determined by single-crystal X-ray diffraction methods. Crystals of adduct (1) are monoclinic, space group P21/a, with four molecules in a cell with dimensions a 7·806(2), b 15·929(2), c 7·861(3) Å, β 113·35(1)°, while (2) is also monoclinic, space group P21, with two dimer units in a cell with a 5·380(3), b 25·72(2), c 7·926(5) Å, β 94·22(3)°. Both form polymer structures which are stabilized by extensive hydrogen bonding. Adduct (1) is based upon a square planar trans-AgN2O2 repeating unit involving bonds to the two independent urea molecule with the perchlorate anion uncoordinated, while with (2), the oxygens of two urea molecules bridge two trigonal bipyramidal (AgNO4) silver centres, forming cyclic pseudo-centrosymmetric four-membered dimer repeats. The silver coordination of (2) also includes two cis-related sulfonate oxygens from bridging p-toluenesulfonate ligands, as well as a third bridging urea amine nitrogen. The result is a step-polymer ribbon structure.