Dynamic nuclear magnetic resonance study of the effects of cis-chelate ligands on 1,2-metallotropic shifts in trimethylplatinum(IV) complexes of pyridazine

Exchange of pyridine and bipyridine ligands in trimethylplatinum(iv) iodide complexes: substituent and solvent effects

“…The structure of [PtMe 3 (4-MeObipy)I] was found to be closely related to the previously reported structure [PtMe 3 (bipy)(OAc)]$(H 2 O) in which the primary coordination sphere of the platinum atom was also built up by the three methyl groups in facial binding fashion, a bipyridine ligand and a monodentate acetate ligand. 25 The N1-Pt1-N2 bite angle in the complexes is close to the value found in [PtMe 3 (bipy)(OAc)]$(H 2 O) (76.7 ), 25 [PtMe 3 (bipy)I] (76.5 ), 23 [PtMe 3 (bipy)Br] (76.6 ), 24 [PtMe 3 (bipy)(pydz)][BF 4 ] (75.3 ), 22 [PtMe 3 (terpy)I] (76.1 ). 41 The Pt-N bond distances in all the structures do not differ signicantly (2.12-2.16 Å).…”

“…All other key bond distances and angles (see Table S1 in the ESI †) are very much comparable to the value for the previously reported mononuclear trimethylplatinum(IV)-bipyridine complexes. 22,25 Reaction of mononuclear pyridine complexes [PtMe The population ratios of the bipyridine complexes to the pyridine complexes and the relative population of different bipyridine complexes for the reaction of 1 : 1 mixture of mononuclear pyridine complexes and corresponding 2,2 0bipyridine ligands in two different solvents (CDCl 3 and nitrobenzene-d 5 ) at different time intervals are tabulated in Table 2. The compositions of the platinum(IV) complexes at different time intervals for all the four ligand-exchange reactions are also given in Tables S3-S10 in the ESI.…”

“…[18][19][20][21] It was also found that trimethylplatinum(IV) complexes of bipyridine ligands exhibit curious dynamic behavior in solution. 22 In this regard, it is somewhat surprising that there exists very few structural reports of trimethylplatinum(IV) complexes of simple 2,2 0 -bipyridine ligand [22][23][24][25][26] and to the best of our knowledge, no structural characterization of simple 4,4 0disubstituted 2,2 0 -bipyridine ligands of trimethylplatinum(IV) iodide complexes has yet been reported. Herein, in the present paper, we report the synthesis and spectroscopic characterization of a series of mononuclear trimethylplatinum(IV) complexes of 2,2 0 -bipyridine ligands, [PtMe 3 (L-L)I] where L-L ¼ 2,2 0 -bipyridine (bipy), 4,4 0 -dimethyl-2,2 0 -bipyridine (4-Mebipy), 4,4 0 -dimethoxy-2,2 0 -bipyridine (4-MeObipy), 4,4 0 -bis(dimethylamino)-2,2 0 -bipyridine (4-Me 2 Nbipy).…”

Substituent effects in solution speciation of the mononuclear and dinuclear trimethylplatinum(iv) iodide complexes of pyridines

“…The Pt-N bond distances in all the structures do not differ significantly (2.17-2.20 Å). A similar feature was also observed in previously reported mononuclear trimethylplatinum(IV)pyridine complexes 19,37,38 and was in contrast to the situation found for the mononuclear trimethylplatinum(IV)-terpyridine complexes where the metal-nitrogen bond distance to the central pyridine ring was longer than the corresponding distance to the outer ring. 39,40 The Pt-I bond distance in all the structures is almost the same.…”

“…All the other key bond lengths and angles were quite similar (Table S4, ESI †) and were very much comparable to the value for the previously reported mononuclear Pt IV -pyridine complexes. 19,37,38 Crystal structures of dinuclear complexes. into the solution containing an equimolar mixture of trimethylplatinum iodide and the corresponding mononuclear pyridine complexes in CDCl 3 at room temperature.…”