Iron and Ruthenium Fragment Substituted Disilanes C5R5(OC)2M–Si2X5 (R = H, Me; M = Fe, Ru; × = Cl, H): Synthesis, Structural and Raman Spectroscopic Characterisation, DFT Calculation

Extremely bulky secondary phosphinoamines as substituents for sterically hindered aminosilanes

The synthesis of a series of extremely bulky secondary amines with a phosphine function, Ar^†(PR₂)NH (Ar^†= C₆H₂{C(H)Ph₂}₂Prⁱ-2,6,4; R = Ph, NEt₂, NPrⁱ₂) is described. Deprotonation with eithern-BuLi or KH yields the respective alkali metal amides. Reactions with a series of chlorosilanes allows access to monomeric molecular compounds bearing the extremely bulky amino substituentsviasalt elimination.

σ-Silane, disilanyl, and [W(μ-H)Si(μ-H)W] bridging silylene complexes via the reactions of W(PMe3)4(η2-CH2PMe2)H with phenylsilanes

W(PMe3)4(η(2)-CH2PMe2)H reacts with PhSiH3 to give the first examples of diphenyldisilanyl compounds, W(PMe3)4(SiH2SiHPh2)H3 and W(PMe3)3(SiH2Ph)(SiH2SiHPh2)H4, via a mechanism that is proposed to involve migration of a SiHPh2 group to a silylene ligand. In addition to the formation of the aforementioned mononuclear compounds, the reaction of W(PMe3)4(η(2)-CH2PMe2)H with PhSiH3 also yields a novel dinuclear compound, [W(PMe3)2(SiHPh2)H2](μ-Si,P-SiHPhCH2PMe2)(μ-SiH2)[W(PMe3)3H2], which features a bridging silylene ligand that participates in 3-center-2-electron interactions with both tungsten centers. The bonding within the [W(μ-H)Si(μ-H)W] core can be described by a variety of resonance structures, some of which possess multiple bond character between tungsten and silicon. In this regard, [W(PMe3)2(SiHPh2)H2](μ-Si,P-SiHPhCH2PMe2)(μ-SiH2)[W(PMe3)3H2] possesses the shortest W-Si bond length reported. The corresponding reaction of W(PMe3)4(η(2)-CH2PMe2)H with Ph2SiH2 yields the σ-silane compound, W(PMe3)3(σ-HSiHPh2)H4.

Synthesis and structural studies of germyl and germyl/stannyl substituted tungstenocenes

One-pot reactions of [WCp2(H)2] and [WCp2(H)(SnMe3)] with "BuLi followed by an equivalent of GeMe2Cl2 afford mono(germyl) substituted tungstenocenes [WCp2(H)(GeMe2Cl)] (1) and [WCp2(SnMe3)(GeMe2Cl)] (7). Reactions of the products with tin halides in the presence NEt3 afford the mixed complexes [WCp2(SnR2X)(GeMe2Y)] (X, Y = Cl, Br, R = Me, Et), which were further converted to moderately stable compounds [WCp2(SnR2H)(GeMe2H)] (R = Me (10), Et (11)). A number of asymmetric mono(halo)-substituted germyl/stannyl tungstenocenes [WCp2(SnMe2X)(GeMe2H)] (X = Cl (12), Br (13)) and [WCp2(SnEt2Y)(GeMe2H)] (Y = Br (14), I (15)) were prepared by selective halogenation of the Sn-H bond in 10 and 11. X-Ray studies of [WCp2(H)(GeMe2Cl)] (1), [WCp2(SnEt2Br)(GeMe2Cl)] (4), and [WCp2(SnEt2Br)(GeMe2H)] (14) established classical structures of these compounds. X-Ray study of complex [WCp2(SnMeCl)(GeMe2Cl)] (3) revealed the presence of interligand Ge-Cl...Sn-Cl interactions in a highly Ge/Sn disordered structure. Analyses of molecular parameters of 1, 4, and 14 suggest the presence of a negative hyperconjugation between metal lone pairs and the sigma*-orbital of the E-X bond, which is stronger in bromo substituted complexes in comparison with chloro substituted ones.