Synthesis and some properties of phosphoimino-1-azaazulene derivatives

3-Phenyl-8-triphenylphosphoimino- and 2-triphenylphosphoimino-1-azaazulenes were prepared by the reaction of the corresponding 8- and 2-amino-1-azaazulenes with triphenylphosphine dibromide. The structure of 3-phenyl-8-triphenylphosphoimino-1-azaazulene was investigated by X-Ray crystallographic analysis and molecular orbital calculation. The P-atom has trigonal bipiramidal coordination and the intramolecular distance between the N-1 and the P-atom is 2.762(6) Angstrom, the existence of an interaction between N-1 and the P-atom is considered.