The synthesis and characterisation of a 1-titanacyclobuta-2,3-diene complex, an organometallic analog of elusive 1,2-cyclobutadiene, is presented.

A new synthetic approach enabled the generation of highly labile thionylimide, H-NSO, which was trapped by adduct formation with the bulky Lewis acid B(C6 F5 )3 and fully characterized. For comparison, a series of different Me3 Si-NSO Lewis acid adducts were studied. Treatment of Me3 Si-NSO with the silylium ion [Me3 Si](+) led to the formation of the hitherto unknown iminosulfonium ion [Me3 Si-N=S-O-SiMe3 ](+) , which could be isolated and fully characterized as a salt in the presence of weakly coordinating carborate anions.

Using titanocene synthon [Cp2Ti(Me3SiC2SiMe3)] the selective conversion of aryl-substituted triphosphiranes P3Ar3 into Cp2TiP2Ar2 complexes was achieved.

Abstract:The reactions of the group 4 metallocene alkyne complexes Cp* 2 M(η 2 -Me 3 SiC 2 SiMe 3 ) (M = Ti, Zr) with different cyanopyridines were investigated. For the zirconium compound, the unstable products Cp* 2 Zr(η 2 -Me 3 SiC 2 SiMe 3 )(N≡C-py) were first formed by the end-on coordination of the substrate. Subsequent reaction with a second equivalent resulted in the elimination of the alkyne and in the formation of 1-zircona-2,5-diazacyclopenta-2,4-dienes. By applying (2-bromo)-5-cyanopyr-

This work describes the unexpected synthesis and characterization of the first persilylated ammonium ion, [(Me 3 Si) 3 NSi(H)Me 2 ] + , in the reaction of (Me 3 Si) 3 N with [Me 3 Si−H−SiMe 3 ][B(C 6 F 5 ) 4 ]. NMR and Raman studies revealed a transition-metal-free silylium ion catalyzed substituent redistribution process when [Me 3 Si−H−SiMe 3 ] + was used as the silylating reagent. These observations were affirmed in the reaction with [Et 3 Si−H−SiEt 3 ][B(C 6 F 5 ) 4 ]. A Lewis acid catalyzed scrambling process always occurs if an excess of silanes is present in the formation of silylium cations while employing the standard Bartlett−Schneider−Condon type reaction. Additionally, the thermodynamics of this process was accessed by DFT computations at the pbe1pbe/aug-cc-pVDZ level, indicating alkyl substituent exchange equilibria at the silane and preference of the formation of [(Me 3 Si) 3 NSi(H)Me 2 ] + over [(Me 3 Si) 4 N] + .

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The reaction of m-terphenyl amine (2,6-bis-(2,4,6-trimethylphenyl)aniline, m-Ter = m-terphenyl = 2,6-bis-(2,4,6-trimethylphenyl)) and ECl(3) (E = P, As) in the presence of different bases (Et(3)N, n-BuLi, LDA, DBU) and under different reaction conditions was studied. The reaction with excess Et(3)N yielded m-Ter-N(H)-AsCl(2) for E = As, while for E = P m-Ter-N(PCl(2))(2) was formed. m-Ter-N(H)-ECl(2) was obtained in the reaction of m-terphenyl amine with n-BuLi and ECl(3) for E = As and P. Further treatment of m-Ter-N(H)-PCl(2) with Et(3)N led to the formation of 1,3-dichloro-cyclo-1,3-diphospha-2,4-diazane, a synthesis protocol which cannot be applied to the analogous arsenic species. 1,3-dichloro-cyclo-1,3-diarsa-2,4-diazane was isolated when DBU was added to m-Ter-N(H)-AsCl(2) at low temperature (-80 °C).

The dinuclear zirconocene chloride complex 1 is a highly active precatalyst for the dehydropolymerisation of methylamine borane. Comparison with mononuclear Zr chlorides and related dinuclear complexes suggests that the nature of the bridging motif is essential for the unique reactivity of 1.