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

Graham Smith, Brett A. Cloutt, Karl A. Byriel and Colin H. L. Kennard

Australian Journal of Chemistry 50(7) 741 - 746
Published: 1997

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.