Study of intramolecular competition between carboxylate and phosphonate for Pt(II) with the aid of a novel tridentate carboxylato-thioether-phosphonato ligand.
The tridentate dianionic ligand 2-[2'-(hydroxyisopropoxyphosphoryl)phenylsulfanyl]benzoate (L(2-)) reacts with cis-[Pt(NH(3))(2)(H(2)O)(2)](2+) to form an S,O-chelate in which the O-coordinated group is either carboxylate or phosphonate, depending on the degree of protonation of the complex. Carboxylate appears to be the stronger ligand, and the stoichiometric reaction between cis-[Pt(NH(3))(2)(H(2)O)(2)](2+) and L(2-) yields the neutral species [Pt(L)(NH(3))(2)], with L bound by sulfanyl and carboxylate groups, both in solution and in the solid state. Upon protonation of [Pt(L)(NH(3))(2)], the stronger basicity of the carboxylate causes the Pt coordination to switch from carboxylate to phosphonate, and the uncoordinated carboxylate group becomes protonated. In methanolic solution, the first-order kinetics of this rearrangement could be observed by (31)P NMR spectroscopy. Both complexes-the carboxylate-bound neutral complex [Pt(L)(NH(3))(2)].H(2)O (triclinic, P1 (no. 2), a=9.529(6), b=9.766(6), c=12.299(7) angstroms, alpha=106.91(2), beta=101.71(2), gamma=102.05(2) degrees, Z=2) and the perchlorate salt of the phosphonate-bound complex [Pt(LH)(NH(3))(2)]ClO(4).H(2)O (monoclinic, P2(1)/c (no. 14), a=12.095(2), b=14.046(2), c=14.448(2) angstroms, beta=95.55(2) degrees, Z=4)-were characterized by X-ray crystallography.
Hamel
Matthieu
M
Laboratoire de Chimie Moléculaire et Thio-organique, UMR CNRS 6507, Université de Caen, ENSICAEN, 6, Bld. Maréchal Juin, 14000 Caen, France.
Rizzato
Silvia
S
Lecinq
Matthieu
M
Sène
Aboubacary
A
Vazeux
Michel
M
Gulea
Mihaela
M
Albinati
Alberto
A
Kozelka
Jirí
J
D000970:Antineoplastic Agents / Q000737:chemistry*; D001565:Benzoates / Q000138:chemical synthesis / Q000737:chemistry*; D002945:Cisplatin / Q000737:chemistry*; D018360:Crystallography, X-Ray; D009682:Magnetic Resonance Spectroscopy; D063065:Organophosphonates / Q000138:chemical synthesis / Q000737:chemistry*; D013440:Sulfides / Q000138:chemical synthesis / Q000737:chemistry
D000970:Antineoplastic Agents; D001565:Benzoates; D063065:Organophosphonates; D013440:Sulfides; D002945:Cisplatin