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Pendant Alkyl and Aryl Groups on Tin Control Complex Geometry and Reactivity with H<sub>2</sub>/D<sub>2</sub> in Pt(SnR<sub>3</sub>)<sub>2</sub>(CNBu<sup>t</sup>)<sub>2</sub> (R = Bu<sup>t</sup>, Pr<sup>i</sup>, Ph, Mesityl)

By Anjaneyulu Koppaka (1446856), Lei Zhu (16642), Veeranna Yempally (1446865), Derek Isrow (1689856), Perry J. Pellechia (1689859) and Burjor Captain (1446871)


The complex Pt­(SnBu<sup>t</sup><sub>3</sub>)<sub>2</sub>­(CNBu<sup>t</sup>)<sub>2</sub>­(H)<sub>2</sub>, <b>1</b>, was obtained from the reaction of Pt­(COD)<sub>2</sub> and Bu<sup>t</sup><sub>3</sub>SnH, followed by addition of CNBu<sup>t</sup>. The two hydride ligands in <b>1</b> can be eliminated, both in solution and in the solid state, to yield Pt­(SnBu<sup>t</sup><sub>3</sub>)<sub>2</sub>­(CNBu<sup>t</sup>)<sub>2</sub>, <b>2</b>. Addition of hydrogen to <b>2</b> at room temperature in solution and in the solid state regenerates <b>1</b>. Complex <b>2</b> catalyzes H<sub>2</sub>−D<sub>2</sub> exchange in solution to give HD. The proposed mechanism of exchange involves reductive elimination of Bu<sup>t</sup><sub>3</sub>SnH from <b>1</b> to afford vacant sites on the Pt center, thus facilitating the exchange process. This is supported by isolation and characterization of Pt­(SnMes<sub>3</sub>)­(SnBu<sup>t</sup><sub>3</sub>)­(CNBu<sup>t</sup>)<sub>2</sub>, <b>3</b>, when the addition of H<sub>2</sub> to <b>2</b> was carried out in the presence of free ligand Mes<sub>3</sub>SnH (Mes = 2,4,6-Me<sub>3</sub>C<sub>6</sub>H<sub>2</sub>). Complex Pt­(SnMes<sub>3</sub>)<sub>2</sub>­(CNBu<sup>t</sup>)<sub>2</sub>, <b>5</b>, can be prepared from the reaction of Pt­(COD)<sub>2</sub> with Mes<sub>3</sub>SnH and CNBu<sup>t</sup>. The exchange reaction of <b>2</b> with Ph<sub>3</sub>SnH gave Pt­(SnPh<sub>3</sub>)<sub>3</sub>(CNBu<sup>t</sup>)<sub>2</sub>­(H), <b>6</b>, wherein both SnBu<sup>t</sup><sub>3</sub> ligands are replaced by SnPh<sub>3</sub>. Complex <b>6</b> decomposes in air to form square planar Pt­(SnPh<sub>3</sub>)<sub>2</sub>­(CNBu<sup>t</sup>)<sub>2</sub>, <b>7</b>. The complex Pt­(SnPr<sup>i</sup><sub>3</sub>)<sub>2</sub>­(CNBu<sup>t</sup>)<sub>2</sub>, <b>8</b>, was also prepared. Out of the four analogous complexes Pt­(SnR<sub>3</sub>)<sub>2</sub>­(CNBu<sup>t</sup>)<sub>2</sub> (R = Bu<sup>t</sup>, Mes, Ph, or Pr<sup>i</sup>), only the Bu<sup>t</sup> analogue does both H<sub>2</sub> activation and H<sub>2</sub>−D<sub>2</sub> exchange. This is due to steric effects imparted by the bulky Bu<sup>t</sup> groups that distort the geometry of the complex considerably from planarity. The reaction of Pt­(COD)<sub>2</sub> with Bu<sup>t</sup><sub>3</sub>SnH and CO gas afforded <i>trans</i>-Pt­(SnBu<sup>t</sup><sub>3</sub>)<sub>2</sub>­(CO)<sub>2</sub>, <b>9</b>. Compound <b>9</b> can be converted to <b>2</b> by replacement of the CO ligands with CNBu<sup>t</sup> via the intermediate Pt­(SnBu<sup>t</sup><sub>3</sub>)<sub>2</sub>­(CNBu<sup>t</sup>)<sub>2</sub>­(CO), <b>10</b>

Topics: Biophysics, Biochemistry, Medicine, Genetics, Molecular Biology, Neuroscience, Sociology, Developmental Biology, Cancer, Infectious Diseases, Computational Biology, Chemical Sciences not elsewhere classified, H 2 activation, Mes 3 SnH, ligand Mes 3 SnH, Pt, HD, Bu t, SnBu t 3 ligands, Bu t groups, Ph 3 SnH, Tin Control Complex Geometry, CO, CNBu t, Bu t 3 SnH, Bu t analogue, 3 C 6 H 2
Year: 2015
DOI identifier: 10.1021/ja511295h.s003
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Provided by: FigShare
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