Synthesis of [Pt(SnBu^t₃)(IBu^t)(μ-H)]₂, a Coordinatively Unsaturated Dinuclear Compound which Fragments upon Addition of Small Molecules to Form Mononuclear Pt–Sn Complexes

Abstract

The reaction of Pt(COD)2 with one equivalent of tri-tert-butylstannane, Bu(t)3SnH, at room temperature yields Pt(SnBu(t)3)(COD)(H)(3) in quantitative yield. In the presence of excess Bu(t)3SnH, the reaction goes further, yielding the dinuclear bridging stannylene complex [Pt(SnBu(t)3)(μ-SnBu(t)2)(H)2]2 (4). The dinuclear complex 4 reacts rapidly and reversibly with CO to furnish [Pt(SnBu(t)3)(μ-SnBu(t)2)(CO)(H)2]2 (5). Complex 3 reacts with N,N'-di-tert-butylimidazol-2-ylidene, IBu(t), at room temperature to give the dinuclear bridging hydride complex [Pt(SnBu(t)3)(IBu(t))(μ-H)]2 (6). Complex 6 reacts with CO, C2H4, and H2 to give the corresponding mononuclear Pt complexes Pt(SnBu(t)3)(IBu(t))(CO)(H)(7), Pt(SnBu(t)3)(IBu(t))(C2H4)(H)(8), and Pt(SnBu(t)3)(IBu(t))(H)3 (9), respectively. The reaction of IBu(t) with the complex Pt(SnBu(t)3)2(CO)2 (10) yielded an abnormal Pt-carbene complex Pt(SnBu(t)3)2(aIBu(t))(CO) (11). DFT computational studies of the dimeric complexes [Pt(SnR3)(NHC)(μ-H)]2, the potentially more reactive monomeric complexes Pt(SnR3)(NHC)(H) and the trihydride species Pt(SnBu(t)3)(IBu(t))(H)3 have been performed, for NHC = IMe and R = Me and for NHC = IBu(t) and R = Bu(t). The structures of complexes 3-8 and 11 have been determined by X-ray crystallography and are reported.

Metal–Metal Bonds: From Fundamentals to Applications

“…Also, dihydrogen activation by the heterobimetallic complex is heterolytic, which is similar to the reactivity characteristic of frustrated Lewis pairs . Captain and co-workers have also shown cooperative heterolysis of dihydrogen using a Pt–Sn bimetallic . On the basis of spectroscopic evidence, the authors propose an intriguing three-center Pt–H–Sn μ-hydride product, which could also be thought of as a platinum σ complex of H–SnR 3 .…”

“…37 Captain and co-workers have also shown cooperative heterolysis of dihydrogen using a Pt−Sn bimetallic. 38 On the basis of spectroscopic evidence, the authors propose an intriguing three-center Pt−H−Sn μ-hydride product, which could also be thought of as a platinum σ complex of H−SnR 3 . Transientmetal−metalbonded species may also play a significant role in palladium crosscoupling catalysis, and such a notion has generated lively debate in recent years.…”

Preparation of Heterobimetallic Ketimido-Actinide-Molybdenum Complexes

“…3 )(COD)(H)] (COD = 1,5-cyclooctadiene). 48 We are unaware of any activation of acetonitrile or other nitriles by metal-metal linkages, but the activation of nitriles by other An complexes in general is well established. For example, the insertion of acetonitrile into the U=C bond of [Cp 3 U=CHP(Ph) 2 Me] was reported to afford [Cp 3 UNC(Me)CHP(Ph) 2 Me] where the newly formed U-N linkage was ascribed multiple bond character due to its very short distance.…”

“…We and others have recently reported examples of heterobimetallic An-TM linkages supported by bridging phoshpino-amide linkages; , ligands of this type have also been shown to stabilize a range of TM–TM linkages in recent years. − The ability of bimetallic species to effect unusual reactivity modes or catalysis is well documented, with examples of naphthyridine–diamine stabilized Ni­(I)–Ni­(I) and Ru­(II)–Ru­(II) complexes being reported to effect the hydrosilylation of alkenes, dienes, alkynes, and other unsaturated substrates for the former and dehydrogenation of alcohols in the latter. , Other examples include the tris (amidinate) Mo–Mo paddlewheel complexes which were reported to activate the C–Cl bond in CCl 4 across an alkene . In particular, heterobimetallic linkages have shown interesting reactivity modes toward small molecules, with the Ag–Ru species [(IMes)-AgRu­(CO) 2 ] being reported to semihydrogenate alkynes, and the heterolytic splitting of dihydrogen by the Pt–Sn bimetallic [Pt­(SnBu 3 t )­(COD)­(H)] (COD = 1,5-cyclooctadiene) . We are unaware of any activation of acetonitrile or other nitriles by metal–metal linkages, but the activation of nitriles by other An complexes in general is well established.…”

“…46 In particular, heterobimetallic linkages have shown interesting reactivity modes toward small molecules, with the Ag−Ru species [(IMes)-AgRu(CO) 2 ] being reported to semihydrogenate alkynes, 47 and the heterolytic splitting of dihydrogen by the Pt−Sn bimetallic [Pt(SnBu 3 t )(COD)(H)] (COD = 1,5cyclooctadiene). 48 We are unaware of any activation of acetonitrile or other nitriles by metal−metal linkages, but the activation of nitriles by other An complexes in general is well established. For example, the insertion of acetonitrile into the UC bond of [Cp 3 UCHP(Ph) linkage was ascribed multiple bond character due to its very short distance.…”