A theoretical study of linear germacyanogen isomers

The structures of all possible linear isomers of Ge-containing cyanogens were optimized at MP2, B3LYP, and QCISD levels of theory. At all levels of theory, the most stable isomer was found to be GeNCN, while for cyanogen itself, the most stable isomer is well known to be NCCN. Our theoretical results predict that the order of stability of the acyclic germacyanogens is GeNCN>GeNNC>NGeCN>NGeNC. The difference between the order of stability among germacyanogen and cyanogen isomers is rationalized, taking into account the position of the unpaired electron on nitrogen in the GeN radical, and that on carbon in the CN radical.