Heavy multiple bond systems violate the double bond rule. Consequently, difficult to access but display high reactivity. Steric shielding allowed the synthesis of heavy multiple bond systems, because the aggregation to higher oligomers was prevented. Landmark studies in the field were conducted by Lappert (distannene), West (disilene), and Sekiguchi (disilyne). At the example of Power's digermyne the first reaction of a main group molecule with dihydrogen at mild conditions could be demonstrated in 2005. The interest in heavy multiple bond systems has grown steadily since and just recently Tokitoh showed that digermynes can catalyse the cyclooligomerisation of alkynes.
Because there is no stable nitrile analogue with a heavy group 14 element known yet, we strive to synthesise heteroatomic triple bond species, such as germa-nitriles (see picture on the right). To achieve this goal, sterically very demanding substituents are required, exceeding the properties of known systems.
The developed synthetic methodology can also be applied to related transition metal compounds which opens up low-coordinate transition metal nitrido complexes as synthetic targets.
A potentially suitable class of substituents was generated on the basis of aryl(silyl)amides. Their steric bulk already exceeds the sterics of known monodentate monoanionic substituents and due to their step-wise synthesis readily modifyable on both the aryl and the silyl group. As with related compounds the preparation of terminal nitrido compounds shall be achieved by photolysis of corresponding azido precursors.
Dr. Alexander Hinz
Karlsruhe Institute of Technology (KIT)
Institute of Inorganic Chemistry (AOC)