Abstract Tetrakis [bis (trimethylsilyl) methyl] dialane (4) 1 reacted with trimethylsilyldiazomethane and bis (trimethylsilyl) diazomethane at room temperature by the insertion of the terminal nitrogen atoms into its aluminium–aluminium bond. As shown by a crystal structure determination, one of the aluminium atoms of each product enhanced its coordination number to four by the interaction with the central nitrogen atom of the C= N– ...