Molecular and electronic structure of 1,3,2-diazaphosphinine derivatives

GRAPHICAL ABSTRACT

ABSTRACT

Structure of 1,3,2-diazaphosphinine heterocyclic system was studied using quantum chemical calculations and X-ray diffraction method for one derivative. It was found that two P–N single bonds were different in their nature: one of them turned out to be significantly shorter and stronger, whereas the other one is longer and more diffused. The found effect is strengthened by π-donor substituents. The effect was interpreted by equilibrium of Lewis structures and analyzing the charge distribution by the NBO approach. The observed effect can be considered as the special form of π-conjugation in the heterocycles with the phosphorus (V) atom included.

KEYWORDS:

• Diazaphosphinine
• DFT
• conjugation
• P–N bonds
• NBO

Acknowledgments

The authors are grateful to Prof. Dr. Uwe Manthe and Dr. Thorsten Tönsing, University of Bielefeld (Germany), for access to the computer cluster and Gaussian 03 packets of programs and also for technical support for the calculations.