Kinetics of site-exchange reactions in di- and tri-methylplatinum(IV) glycinate complexes, from N.M.R. lineshape analysis

Abstract

Site-exchange reactions for PtMe3(gly)(D2O), and isomers of PtMe2Br(gly)(D2O) with D2O coordinated trans to methyl have been studied, and rate constants determined by complete line shape analysis of 1H n.m.r. spectra in the methyl region (gly = H2NCH2CO2-). It is proposed that these reactions involve exchange of the labile water molecule with solvent water, with an associated migration of a donor atom (nitrogen or oxygen). Dissociative and associative (edge displacement) reaction pathways compete. The site-exchange reaction for PtMe3(gly)2- appears to occur by dissociation of a Pt-O bond.

Oxidation of Methylplatinum(II) Complexes K[(L)PtIIMe] with O2 and C(sp3)-X (X = O and C) Reductive Elimination Reactivity of Methylplatinum(IV) Products (L)PtIVMe(OH): The Effect of Structure of Sulfonated CNN-Pincer Ligands L

“…The remaining two signals of equal intensity at 1.25 ppm ( 2 J 195PtH = 65 Hz) and 0.85 ppm ( 2 J 195PtH = 69 Hz) were assigned to 13b . A facile isomerization of trihydrocarbylplatinum­(IV) species was reported earlier. − …”

Synthesis of dimethylplatinum(IV) compounds, [{PtMe2X2}n], [{PtMe2XY}n], and, in solution,fac-[PtMe2X(H2O)3]+, where X and Y are anionic ligands

“…Displacement of water molecules coordinated cis to the methyl ligands requires heating or long standing. Exploitation of the differential lability of the aqua ligands in dimethylplatinum(1V) complexes, combined with the photolabilization of coordination sites trans to bromide in dimethylbromo compounds (7), has allowed the synthesis of a wide range of derivatives -for example, with amino acids and related ligands (6,(8)(9)(10)(11)(12)(13)(14). These compounds were all prepared using 2 or 3 as starting material.…”