Hydrogen bonding patterns in pyrazole Pt(II- and IV) chloride complexes

The solid-state packing arrays of the platinum(II) trans- and cis-[PtCl2(PzH)(2)] (1 and 2) and platinum(IV) trans- and cis-[PtCl4(PzH)21 (3 and 4) complexes have been examined and the occurrence of N-(HCl)-Cl-... hydrogen-bonding associations in those structures has been discussed. Although different packing motifs are observed, in all cases molecules are interacting mostly via (NHCl)-Cl-... and (CHCl)-Cl-... associations. The square planar 1 and 2 form stacked arrays of PtCl2(PzH)(2), which are supported by (NHCl)-Cl-... and (CHCl)-Cl-... hydrogen bonding. The isomeric structure of the complexes and orientation of the PzH rings determine (NHCl)-Cl-... bonding mode (intermolecular or intramolecular) and also the extent of the platinum-platinum interaction. The synthetic procedures for the preparation of 1-4 along with elemental and X-ray analyses, TG/DTA, FAB(+)-MS, IR, and H-1 and C-13{H-1} NMR data are also given in this article. (c) 2005 Elsevier B.V. All rights reserved.