Crystal structures of three hexakis­(fluoroar­yloxy)cyclo­triphosphazenes

The syntheses and crystal structures of three cyclo­triphosphazenes, all with fluorinated ar­yloxy side groups that generate different steric characteristics, viz. hexa­kis­(penta­fluoro­phen­oxy)cyclo­triphosphazene, N(3)P(3)(OC(6)F(5))(6), 1, hexa­kis­[4-(tri­fluoro­methyl)­phen­oxy]cyclo­triphosphazene, N(3)P(3)[OC(6)H(4)(CF(3))](6), 2 and hexa­kis­[3,5-bis(­tri­fluoro­methyl)­phen­oxy]cyclo­triphosphazene, N(3)P(3)[OC(6)H(3)(CF(3))(2)](6) 3, are reported. Specifically, each phospho­rus atom bears either two penta­fluoro­phen­oxy, 4-tri­fluoro­methyl­phen­oxy, or 3,5-tri­fluoro­methyl­phen­oxy groups. The central six-membered phosphazene rings display envelope pucker conformations in each case, albeit to varying degrees. The maximum displacement of the ‘flap atom’ from the plane through the other ring atoms [0.308 (5) Å] is seen in 1, in a mol­ecule that is devoid of hydrogen atoms and which exhibits a ‘wind-swept’ look with all the aromatic rings displaced in the same direction. In 3 an intra­molecular C—H(aromatic)⋯F inter­action is observed. All the –CF(3) groups in 2 and 3 exhibit positional disorder over two rotated orientations in close to statistical ratios. The extended structures of 2 and 3 are consolidated by C—H⋯F inter­actions of two kinds: (a) linear chains, and (b) cyclic between mol­ecules related by inversion centers. In both 1 and 3, one of the six substituted phenyl rings has a parallel-displaced aromatic π–π stacking inter­action with its respective symmetry mate with slippage values of 2.2 Å in 1 and 1.0 Å in 3. None of the structures reported here have solvent voids that could lead to clathrate formation.