RROLIDINO-N)PHOSPHONIUM]TRIFLUOROMETHANESULFONATE, A SALT WITH A DIPHOSPHONIUM ION WITH A NONLINEAR P-O-P SEQUENCE

The title compound contains the diphosphonium ion, [(C4H3N)(3)P-O-P(NC 4H8)(3)](2+). The structure of the compound is disordered at room temp erature. By slow cooling, it goes through a phase transition near -100 degrees C and as a result becomes ordered. Unlike the similar cations [(Me(2)N)(3)P-O-P(NMe(2))(3)](2+), and [(OC4H8N)(3)P-O-P(NC4H8O)(3)]( 2+), it has a non-linear P-O-P sequence both in the disordered and ord ered phase with P-O-P angles between 155.5(3) and 159.2(3)degrees. The X-ray crystallographic study of the title compound, both at 273 and 1 03 K, shows that the P-O and P-N bond lengths are very similar to thos e of the linear cations. The P-O and P-N bond lengths in the title com pound ranges from 1.578(4) to 1.602(4) Angstrom and from 1.585(5) to 1 .605(5) Angstrom, respectively.