Trimethylplatinum complexes

Nitrogen ligands, which tend to coordinate to three meridional coordination sites of five- and six-coordinated transition metal centers, form trimethylplatinum complexes with these ligands as bidentates 974 and 975. "" ""... 

The magnitude of coupling between the methyl protons and platinum-195 also is helpful in assigning structures to trimethylplatinum(IV) complexes. The 2J(195Pt-CH3) coupling constant appears to be influenced primarily by the nature of the ligand trans to the methyl group, and the solvent used makes little difference (33, 54). This same effect... 

Clegg and Hall (8) noted that the addition of sulfuric acid to an aqueous solution of [(CH3)3Pt(NH3)3]Cl caused a shift of 0.5 ppm in the methyl proton resonance and an increase in the value of 2/( 195Pt-CH3) from 71.0 to 79.7 Hz because of rapid formation of the triaquo species. Addition of an excess of the ligands H3CNH2, pyridine, SCN", N02", and CN" all gave rise to spectra characteristic of the complexed trimethylplatinum (IV) cation (7). 

Telluranthrene formed complexes in reactions with pentacarbonylrhenium bromide and trimethylplatinum bromide2. 

Vhpi coupling of 79 Hz has been found by De Crisci et al for the neutral platinum (IV) complex, [(c/os o-CBnH6Br6)PtMe3], containing the c/oxo-CBiiHgBrg anion bonded to the trimethylplatinum(IV) cation via three boron-bound bromines, and used as indicator of the donor strength of the tripodal cap. The authors concluded that c/ojo-CBnHeBre- is a relatively weak donor towards the PtMe cation. 

A Pt-Ir dinuclear complex with trimethylplatinum(IV)- and bridging pyrazolide ligands 991 has been reported7 ... 

A trimethylplatinum(iv) complex with tris(3,5-bistrifluoromethylpyrazolyl)borate as a ligand has been prepared and studied by H-F two-dimensional NMR spectroscopy the spectra exhibit long-range G-H-F-C interaction which is evidenced also by IR spectra.1,4,7-Triazacyclononane coordinates to the Pt(ii) center as a bidentate ligand and to the Pt(iv) center as a facial tridentate ligand. Square-planar dimethylplatinum(ii) complex 1006 is in equilibrium with the octahedral hydrido (dimethyl)platinum(iv) complex 1007 in MeOH via reversible protonation of the Pt(ii)... 

The dimethylplatinum(ll) complex with a bidentate iV,iV,iV -trimethyl-A -(2-picolyl)ethylenediamine ligand undergoes methylation by Mel and protonation by several protic acids to produce cationic trimethylplatinum(iv) complex 1018 and methylplatinum(ll) complex 1019, respectively (Scheme 129). The protonation involves an intermediate cationic hydrido(dimethyl)platinum(lv) complex 1020. Scrambling of hydrogen atoms between hydride and methyl ligands during the reaction indicates an intermediate complex with methane as a ligand. 

Methylation of complex 20 using MeOTf has afforded dinuclear trimethylplatinum(iv) complexes that exist as an equilibrated mixture of 1021 and 1022 (Equation (189))." The complexes are in equilibrium via rotation of the C-C bonds of the ligand. 

Heating the acetate complex 1040 results in reductive elimination of methyl acetate to form the dimethylplatinum(ii) complex or of ethane to form the methyl(acetato)platinum(ii) complex, depending on the polarity of solvent.A cationic trimethylplatinum(iv) intermediate is proposed for the former reaction. 

Platinum(n) to Platinumljw). The stereochemistry of oxidative addition to the platinum(n) complexes [PtMeaCLL)] has been determined for LL = the bidentate arsenic ligands (9) and (10). The oxidative addition of methyl halides gives the 1,2,3-or /ac-trimethylplatinum(iv) compound (11) it is not possible to choose between cis and traits addition from this observation. 

Phosphorus-31 2D-EXSY NMR spectra have afforded evidence of sym-cis/sym-trans interconversions in a series of cyclopalladated tertiary phosphite complexes of type [Pd(/i-Cl)(P(OR )2(OC6H3R ))]2. The platinum analog behaved in a similar manner/ P NMR 2D-EXSY spectroscopy was also employed to probe the dynamics of interconversion between covalent and dative metal-bonded isomers of the mixed metal dinuclear complex [NiPd(CNMe)3(dppm)2](PF6)2. Isomer populations were strongly solvent-dependent with free energies of activation for interconversion of ca 67 kJ mol at 298 Dinuclear complexes of trimethylplatinum(IV) halides have been synthesized (26). The dominant solution structures were... 

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