Synthesis and crystal structure of tris(2,3-triphenylenedioxy)cyclotriphosphazene: a new clathration system

A new host compound TTPP (tris(2,3-triphenylenedioxy)cyclotriphosphazene), which is able to form a porous network, has been synthesized in five steps. When it crystallizes as a single component, TTPP exhibits a crystal structure with a monoclinic unit cell, the space group P21/c (no. 14) and unit cell dimensions of a = 14.909(2) A, b = 31.013(4) A, c = 9.074(1) A, [small beta] = 102.12(1)[degree]. Co-crystallization of TTPP with 1,2,4-trichlorobenzene forms an inclusion crystal having a triclinic unit cell with a P[1 with combining macron] space group (no. 2) and unit cell dimensions of a = 8.769(2) A, b = 15.024(2) A, c = 21.216(2) A, [small alpha] = 94.82(0)[degree], [small beta] = 99.98(0)[degree], [gamma] = 98.23(1). The guest lies in two kinds of channel-like cavities with dimensions of 6.1 [times] 8.4 A2 and 10.7 [times] 12.4 A2 respectively. This represents the biggest porous network built up by spirocyclotriphosphazene derivatives to date.