Tertiary phosphine abstraction from a platinum(II) coordination complex with SeCN−: Crystal and molecular structures of SePTA and [SePTA-Me]I · CH3OH

Reacting [PtCl(PTA)3]Cl(PTA = 1,3,5-triaza-7-phosphatricyclo[3.3.1.13,7]decane) with KSeCN in aqueous or MeOH medium results in the abstraction of the PTA ligands to yield SePTA. The reaction also proceeds quantitatively by direct reaction of PTA and KSeCN in water or methanol. The methylated PTA ligand, [PTA-Me]I (1-methyl-1-azonia-3,5-diaza-7-phosphatricyclo[3.3.1.13,7]decane iodide), reacts accordingly with KSeCN, albeit significantly slower. The crystal structure of SePTA, 1, and [SePTA-Me]I · CH3OH, 2, revealed PSe bond distances of 2.0991(19) and 2.100(2) Å, respectively. The first order phosphorous selenium coupling constants, 1JP–Se (D2O), of 722 and 788 Hz for SePTA and [SePTA-Me]I, respectively, indicates the latter is significantly less electron rich.

Graphical abstractReacting [PtCl(PTA)3]Cl (PTA = 1,3,5-triaza-7-phosphatricyclo[3.3.1.13,7]decane) with KSeCN in water or MeOH results in abstraction of PTA to yield SePTA. The reaction also proceeds by reaction of PTA or the methylated PTA ligand, [PTA-Me]I with KSeCN in water or methanol. The crystal structures of SePTA and [SePTA-Me]I · CH3OH are reported.Figure optionsDownload full-size imageDownload as PowerPoint slide