Reactions of hydrogenated thiamine derivatives with K2[MX4], where M is PdII or PtII and X is Cl or Br

Abstract

The reactions of K₂[MX₄], where M is Pd^II or Pt^II and X is Cl or Br, with the hydrogenated thiamine derivatives L, 3-[(4′-amino-2′-methyl-5′-pyrimidinyl)methyl]-5-(β-hydroxyethyl)-4-methylthiazolidine (L¹), 3-[(4′-amino-2′-methyl-5′-pyrimidinyl)methyl]-5-(β-hydroxyethyl)-4-methylthiazoline (L²), 3-[(4′-amino-2′-methyl-5′-pyrimidinyl)methyl]-4-methyl-5-(β-monophosphatoethyl)thiazolidine (L³), 3-[(4′-amino-2′-methyl-5′-pyrimidinyl)methyl]-4-methyl-5-(β-pyrophosphatoethyl)thiazolidine (L⁴) and their deuteriated derivatives, have been studied in aqueous solutions at pH ca. 1 and 5.5. The products, [ML₂X₂].2HX and [ML₂X₂], have been isolated from these studies and characterized by elemental analyses, conductivity measurements, pH-metric titrations, i.r., ¹H n.m.r., and ¹³C n.m.r. spectra. A complete assignment of the ¹H and ¹³C n.m.r. spectral resonances is presented for both the ligands and the complexes. The results show that the ligands are protonated primarily at the N¹′ atom of the pyrimidine moiety, while the metallation site is either the N³ or the S atom of the thiazoline or thiazolidine ring.