Abstract ▼ AI-Helper

Complexes of the type Pd(tripod)X2 [tripod = MeC(CH2PPh2)3; X = Cl (1), Br (2), I (3)] and Pt(tripod)X2 [X = Cl (4), Br (5), I (6)] have been synthesized. In these complexes tripod acts as a bidentate chelating ligand. The uncoordinated phosphorus atom can bind to AuI to form the bimetallic complex...

Complexes of the type Pd(tripod)X2 [tripod = MeC(CH2PPh2)3; X = Cl (1), Br (2), I (3)] and Pt(tripod)X2 [X = Cl (4), Br (5), I (6)] have been synthesized. In these complexes tripod acts as a bidentate chelating ligand. The uncoordinated phosphorus atom can bind to AuI to form the bimetallic complexes PdAu(tripod)X3 [X = Cl (7), Br (8), I (9)] and PtAu(tripod)X3 [X = Cl (10), Br (11), I (12)]. Complexes (1)-(12) have been characterized by microanalysis, f.a.b. mass spectrometry, i.r. spectroscopy, 31P and 195Pt n.m.r. spectroscopies, and conductivity measurements. The structures of complexes (1), (4) and (11), as well as that of the unusual complex Cl2Pt(tripod)AuBr0.5Cl0.5 (13), isolated from reaction of Pt(tripod)Br2 (5), and [Au(thiodiglycol)Cl], have been determined. All complexes show square-planar geometry for PdII or PtII and linear geometry for AuI. The X-ray crystal structure of (1) showed partial oxidation of the dangling phosphorus of the ligand in 50% of the molecule distributed randomly over the lattice. Reactions of complex (4), Pt(tripod)Cl2, with the tripeptide glutathione (GSH) showed the formation of [Pt2(tripod)2(GS-µ-S)2]2+ (15a). No reaction with N-acetyl-L-methionine (AcMet) or guanosine 5´-monophosphate (5´-GMP) was observed. Reactions of [Pt(tripod-O)(ONO2)2] (14) with GSH resulted in the formation of [Pt2(tripod-O)2(GS-µ-S)2]2+ (15b). Displacement of the S-containing molecules by 5´-GMP in the presence of AuI, via Pt-S bond cleavage, was observed for complex (15b). PtAu(tripod)Cl3 (10) reacted with GSH, with initial attack on the AuI centre.