From planar to nonplanar cyclotriphosphazenes

Abstract A possible existence of planar (PNX 2 ) 3 cyclotriphosphazene, where X = H, F, Cl and Br, or nonplanar (PXNX) 3 was studied at the B3LYP/6-311++G ∗∗ and MP2/6-311++G ∗∗ level of calculations. A linear correlation of total electronic energy difference (Δ E  =  E nonplanar  −  E planar ) on electronegativity of the X substituent was observed. The more stable nonplanar form was predicted (Δ E  = −43.49 kcal/mol) only in case of X = H. The remaining planar halogenocyclotriphosphazenes are more stable, in agreement with a few available experimental data.