Reversible radical complex formation of an organometallic diplatinum(IV) compound

Crystallographically characterized anti-[(μ-bmptz){fac-PtBrMe3}2], bmptz = 3,6-bis(2-(4-methylpyridyl))-1,2,4,5-tetrazine, could be reversibly reduced at −0.36 V vs. [FeCp2]+/∘ in CH2Cl2/0.1 M Bu4NPF6 to a persistent anion. Despite the presence of two conjugatively coupled platinum(IV) centers and the bromide ligands as potential leaving groups it is the bridging bmptz ligand which accepts the added electron within the tetrazine ring as evident from EPR and UV–Vis spectroelectrochemistry of that diplatinum(IV) radical complex. The function of the methyl groups in the [fac-PtMe3]+ ions is discussed in contrast with the related entity [fac-Re(CO)3]+.

Despite the presence of two platinum(IV) centers and two bromide ligands as potential leaving groups the complex anti-[(μ-bmptz){fac-PtBrMe3}2] accepts the first added electron in the tetrazine ring to form a spectroscopically (EPR, UV–Vis) detectable radical anion.Figure optionsDownload as PowerPoint slide