Diazomethane Derivatives Bearing Dialkylaluminium or DialkylgalliumSubstituents – The Isomeric Diazomethane and Nitrile Imine Structures Realized by the Different Coordination Behavior of Aluminium and Gallium
✍ Scribed by Werner Uhl; Frank Hannemann; Wolfgang Saak; Rudolf Wartchow
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 252 KB
- Volume
- 1999
- Category
- Article
- ISSN
- 1434-1948
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✦ Synopsis
Lithium trimethylsilyldiazomethanide Li(SiMe 3 )CN 2 reacted chloride, and the aluminium atom in 2 is attached to the carbon atom of diazomethane. The almost linear N-N-C with the dialkylaluminium or -gallium halides R 2 AlCl and R 2 GaBr [R = CH(SiMe 3 ) 2 ] by the elimination of lithium halide group (174.1°) has N-N and N-C distances of 120.0 and 126.4 pm, respectively, inverse to that of the gallium derivative. and the formation of the corresponding aluminium or gallium diazo compounds. As shown by a crystal structure
The bonding situations can best be described by the resonance structures R-CϵN + -N --GaR 2 for 1 and R 2 Al-determination, the gallium derivative 1 adopts the nitrile imine structure, in which the gallium atom is coordinated by (R)C=N + =N -for 2. The nitrile imine isomer of the aluminium compound could be detected by NMR spectroscopy as a by-the terminal nitrogen atom of the diazo group. The N-N-C-Si moiety is almost ideally linear with N-N and C-N bond product. Both compounds gave dimers in the solid state, a Ga 2 N 2 four-membered heterocycle was formed of 1, while an lengths of 125.5 and 115.9 pm on average. In contrast, the diazomethane structure was formed with dialkylaluminium eight-membered Al 2 C 2 N 4 heterocycle resulted with 2.