μ-OXO-BIS[TRIS(PYRROLIDINO-N)PHOSPHONIUM] TRIFLUOROMETHANESULFONATE, A SALT WITH A DIPHOSPHONIUM ION WITH A NON-LINEAR P[sbnd]O[sbnd]P SEQUENCE
Taylor & Francis
Phosphorus, Sulfur, and Silicon and the Related Elements
The title compound contains the diphosphonium ion, [(C4H8N)3P[sbnd]O[sbnd]P(NC4H8)3]2+. The structure of the compound is disordered at room temperature. By slow cooling, it goes through a phase transition near −100°C and as a result becomes ordered. Unlike the similar cations [(Me2N)3P[sbnd]O[sbnd]P(NMe2)3]2+, and [(OC4H8N)3P[sbnd]O[sbnd]P(NC4H8O)3]2+, it has a non-linear P[sbnd]O[sbnd]P sequence both in the disordered and ordered phase with P[sbnd]O[sbnd]P angles between 155.5(3) and 159.2(3)°. The X-ray crystallographic study of the title compound, both at 273 and 103 K, shows that the P[sbnd]O and P[sbnd]N bond lengths are very similar to those of the linear cations. The P[sbnd]O and P[sbnd]N bond lengths in the title compound ranges from 1.578(4) to 1.602(4) Å and from 1.585(5) to 1.605(5) Å, respectively.