Sn–H bond additions to asymmetric trigonal phosphinidene-bridged dimolybdenum complexes. Issue 53 (30th June 2017)

• Record Type: Journal Article
• Authors: Alvarez, M. Angeles; Amor, Inmaculada; García, M. Esther; García-Vivó, Daniel; Ruiz, Miguel A.; Suárez, Jaime
• Is Part Of: RSC advances. Volume 7:Issue 53(2017)
• Page Start: 33293
• Page End: 33304
• Publication Date: 2017-06-30
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c7ra06439j
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : Organotin hydrides add across the Mo–P double bond of binuclear phosphinidene complexes, sometimes undergoing dehydrogenation involving a cyclopentadienyl ring. Abstract : The reactions between organotin hydrides HSnR3 (R = Bu, Ph) and the asymmetric trigonal phosphinidene-bridged complexes [Mo2 Cp(μ-κ 1 :κ 1, η 5 -PC5 H4 )(CO)2 (η 6 -HMes*)] (1 ), [Mo2 Cp2 (μ-PH)(CO)2 (η 6 -HMes*)] (2 ), and [Mo2 Cp2 (μ-PMe)(CO)2 (η 6 -HMes*)] (3 ) were examined, and found to be strongly dependent on the parent complex (Mes* = 2, 4, 6-C6 H2 t Bu3 ). Compound1 reacted with HSnR3 upon moderate heating (353–363 K), to give the corresponding derivatives [Mo2 Cp{μ-κ 1 :κ 1, η 5 -P(H)C5 H4 }(SnR3 )(CO)2 (η 6 -HMes*)], following from a formal 1, 2-addition of the Sn–H bond across the Mo–P double bond of the parent complex, with specific formation of Sn–Mo and H–P bonds. Complex2 reacted analogously, but much faster, to yield the corresponding phosphanyl-bridged derivatives [Mo2 Cp2 (μ-PH2 )(SnR3 )(CO)2 (η 6 -HMes*)] at room temperature. However, these products progressively degraded to the corresponding mononuclear phosphine complexes trans -[MoCp(SnR3 )(CO)2 (PH3 )] in the presence of trace amounts of water. The methylphosphinidene-bridged complex3 (Mo–P = 2.550(3) and 2.281(3) Å) was prepared upon reaction of MeLi with the phosphide-bridged complex [Mo2 Cp2 (μ-P)(CO)2 (η 6 -HMes*)](BAr′4 ), (Ar′ = 3, 5-C6 H3 (CF3 )2 ). Its reaction with HSnR3 proceeded at room temperature with H–Sn bond addition now accompanied by spontaneous dehydrogenation, to yield the corresponding cyclopentadienylidene–phosphanyl derivatives [Mo2 Cp{μ-κ 1 :κ 1, η 5 -P(Me)C5 H4 }(SnR3 )(CO)2 (η 6 -HMes*)]. The structures of the new complexes were analyzed using spectroscopic, diffractometric and, in some cases, density functional theory methods. The Sn–H bond cleavages leading to the complexes eventually isolated in these reactions were proposed to be initiated by σ-bond coordination of the organotin reagent, via its Sn–H bond, to the metal atom of the MoCp(CO)2 fragment in the parent compounds, this being followed by a H-shift to the P atom of the bridging phosphinidene ligand.