Our group has had a long standing interest in fundamental nitrogen chemistry. In a recent paper, Chem. Eur. Journal, 2015,54,13739, (http://dx.doi.org/10.1002/chem.201501241 ) we have demonstrated a new way to stabilize chains of nitrogen atoms such as in 2. In this project this strategy and scheme will be tested and extended to include longer chains and heterocycles.
Clearly the capacity for synthetic development is enormous with this strategy. What are the limits? There is no reason why we cannot build even longer chains!