Reaction of platinum(II) derivatives with 1-hydroxyalkyl-3,5-dimethylpyrazole ligands. Cleavage of the N(pz)C(sp 3) bond. X-ray crystal structure of cis-[PtCl 2(HL 2) 2] (HL 2=1-(2-hydroxyethyl)-3,5-dimethylpyrazole) and trans-[PtCl 2(dmpz) 2] (dmpz=3,5-dimethylpyrazole)

Abstract

The reactions of 1-hydroxymethyl-3,5-dimethylpyrazole (HL 1) and 1-(2-hydroxyethyl)-3,5-dimethylpyrazole (HL 2) with several platinum starting materials ([PtCl 2(CH 3CN) 2], cis- and trans-[PtCl 2(PhCN) 2], PtCl 2 and K 2PtCl 4) under different conditions have been examined and compared with those obtained from the reactions with Pd(II). cis and trans Pt(II) adducts are obtained in a different ratio depending on the metallic starting complex. The reaction of HL 1 with any of the Pt(II) complexes differs from that with Pd(II) and also from the equivalent reaction of HL 2 with Pt(II). This reaction implies the rupture of the ligand: the cleavage of the N(pz)C(sp 3) bond leads to [PtCl 2(dmpz) 2] (dmpz=3,5-dimethylpyrazole). For comparison, the direct reaction of dmpz with Pt(II) has also been studied. The crystal structure of cis-[PtCl 2(HL 2) 2] and trans-[PtCl 2(dmpz) 2] are here reported.