Selective [2+1+1] Fragmentation of P by heteroleptic Metallasilylenes.

Small-molecule activation by low-valent main-group element compounds is of general interest. We here report the synthesis and characterization ( H, C, Si NMR, IR, sc-XRD) of heteroleptic metallasilylenes L (Cl)MSiL (M=Al 1, Ga 2, L =HC[C(Me)NDipp] , Dipp=2,6- Pr C H ; L =PhC(N Bu) ). Their electronic nature was analyzed by quantum chemical computations, while their promising potential in small-molecule activation was demonstrated in reactions with P , which occurred with unprecedented [2+1+1] fragmentation of the P tetrahedron and formation of L (Cl)MPSi(L )PPSi(L )PM(Cl)L (M=Al 3, Ga 4).

Synthesis, electronic nature, and reactivity of selected silylene carbonyl complexes.

Room-temperature stable main group element carbonyl complexes are rare. Here we report on the synthesis of two such complexes, namely gallium-substituted silylene-carbonyl complexes [L(X)Ga]SiCO (X = I 2, Me 3; L = HC[C(Me)NDipp], Dipp = 2,6-PrCH) by reaction of three equivalents of LGa with IDippSiI (IDipp = 1,3-bis(2,6-PrCH)-imidazol-2-ylidene) or by salt elimination from [L(Br)Ga]SiCO with MeLi. Both silylene carbonyl complexes were spectroscopically characterized as well as with single crystal X-ray diffraction (sc-XRD), while their electronic nature and the specific influence of the Ga-substituents X was evaluated by quantum chemical computations.

A silicon-carbonyl complex stable at room temperature.

Main-group-element compounds with energetically high-lying donor and low-lying acceptor orbitals are able to mimic chemical bonding motifs and reactivity patterns known in transition metal chemistry, including small-molecule activation and catalytic reactions. Monovalent group 13 compounds and divalent group 14 compounds, particularly silylenes, have been shown to be excellent candidates for this purpose. However, one of the most common reactions of transition metal complexes, the direct reaction with carbon monoxide and formation of room-temperature isolable carbonyl complexes, is virtually unknown in main-group-element chemistry.

Synthesis and structures of gallaarsenes LGaAsGa(X)L featuring a Ga-As double bond.

Three equivalents of LGa {L = HC[C(Me)N(2,6-i-PrCH)]} react with AsX (X = Cl, Br) by insertion into two As-X bonds, followed by the elimination of LGaX and formation of LGaAsGa(Cl)L (1) and LGaAsGa(Br)L (2). According to single crystal X-ray analysis, 1 and 2 each exhibit one Ga-As single bond and one Ga-As double bond. The π-bonding contribution (9.