Synthesis and crystal structure of tris(9,10-phenanthrenedioxy)cyclotriphosphazene. A new clathration system

Tris(9,10-phenanthrenedioxy)cyclotriphosphazene forms inclusion adducts wit h a wide range of organic small molecules. This novel host molecule crystal lized with p-xylene to form a triclinic 1:1 inclusion adduct, space group P (1) over bar (No. 2), having unit cell of dimensions a = 12.724(3) Angstro m, b = 19.347(5) Angstrom, c = 9.124(5) Angstrom and alpha = 97.55(3)degree s, beta = 106.13333 degrees, gamma = 72.46(2)degrees, Z = 2. In this adduct , p-xylene is confined within both cage and tunnel-like voids of the host l attice. The same host crystallized with 1,2-dichlorobenzene to form an orth orhombic inclusion adduct, space group P2(1)2(1)2(1) (No. 19), having a uni t cell of dimensions a = 14.880(3) Angstrom, b = 23.277(4) Angstrom, c 13.4 29(4) Angstrom, and Z = 4. In general, the guest to host molar ratios for t he 1,2-dichlorobenzene adduct varied from 1.1:1 to 1.3:1. 1,2-Dichlorobenze ne, o-xylene, p-xylene, benzene, tetrahydrofuran, and cyclohexane were dire ctly imbibed by tris(9, 10-phenanthrenedioxy)cyclotriphosphazene to form ai r stable inclusion adducts. Powder X-ray diffract-ion of these adducts indi cated that the crystal lattice formed is highly guest dependent. Inclusion adducts containing 1,2-dichlorobenzene, o-xylene, and p-xylene as guests we re more stable than those containing tetrahydrofuran, benzene, or hexane. S elective inclusion of cyclohexane and o-xylene was achieved from hexane/cyc lohexane and p-xylene/o-xylene mixtures.