Transformations and Reactions of Re2(CO)8(μ-SbPh2)(μ-H) Induced by the Addition of a Platinum(tri-t-butylphosphine) Group

• Published in: Inorganic chemistry 2009-01, Vol.48 (2), p.652-662
• Main Authors: Adams, Richard D, Hall, Michael B, Pearl, William C, Yang, Xinzheng
• Format: Article
• Language: English
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/ic801876s

Three products Re2[Pt(PBut 3)](μ-SbPh2)(CO)8(μ-H), 2, Re2[Pt(CO)(PBut 3)]Ph(CO)8(μ3-SbPh)(μ-H), 3, and Re2[Pt(PBut 3)]2(CO)8(μ4-Sb2Ph2)(μ-H)2, 4, were obtained from the reaction of Re2(CO)8(μ-SbPh2)(μ-H), 1, with Pt(PBut 3)2. Compound 3 was also obtained from 2 by further reaction with Pt(PBut 3)2. Compound 2 is a Pt(PBut 3) adduct of 1 formed by the insertion of the platinum atom into one of the Re−Sb bonds of 1 with formation of two Pt−Re bonds. Compound 3 contains an open Re2Pt cluster and was also obtained in a low yield by the addition of CO to 2. The addition of SbPh3 to 2 yielded the compound Re2Pt(PBut 3)(Ph)(CO)8(SbPh3)(μ3-SbPh)(μ-H), 5, a SbPh3 derivative of 3. Compound 4 can be viewed as a dimer of the fragment Re[Pt(PBut 3)](CO)4(SbPh)(μ-H). The two halves of the molecule are held together by Pt−Sb bonds and a significant interaction directly between the Sb atoms, Sb−Sb distance, 2.9834(7) Å. The Sb−Sb bonding in 4 was explained by density functional calculations. Compound 4 adds 2 equiv of CO at 1 atm/25 °C, one to each platinum atom, to yield the compound [Re(CO)4Pt(H)(CO)(PBut 3)(μ3-SbPh)]2 which exists as a mixture of two noninterconverting isomers, cis-6 and trans-6. Both isomers of 6 were isolated and structurally characterized. Each isomer of 6 consists of a central planar Re2Sb2 core composed of two Re(CO)4 groups with two bridging SbPh ligands. There is a Pt(H)(CO)(PBut 3) group coordinated to each antimony atom of 6. In the cis-isomer both Pt(H)(CO)(PBut 3) groups lie on the same side of the Re2Sb2 plane. In the trans-isomer the Pt(H)(CO)(PBut 3) groups lie on opposite sides of the Re2Sb2 plane.