Structures of inorganic rings as antitumor agents. II. Structure of the benzene clathrate of 2,2,4,4,6,6-hexa(1-aziridinyl)cyclotri(phosphazene), N₃P₃az₆

Abstract

Abstract2CI2H24N9P3. C6H6, M r = 852.71, is rhombohedral, space group R3, with a = 10.266(1)A, (t-79.21 (1) °, Z = 1, D e = 1.374 Mg m -3, 2(Mo Kal) = 0.70926 A,/1 = 0.260 mm -I, T = 288 + 0.05 K. The structure was solved by the heavy-atom method. R = 0.026 for 1206 independent reflections. The two cyclotri(phosphazene) molecules are related by the symmetry centre, the benzene is at the centre, and all three molecules lie on the crystallographic C 3 axis; in the cyclotri(phosphazene), the geminal aziridinyl groups adopt an unusual eis conformation.

Structures of inorganic rings as antitumor agents. III. Structures of the monoclinic and orthorhombic forms of 2,2,4,4,6,6-hexa(1-aziridinyl)cyclotri(phosphazene), N3P3az6

“…4c), and is quite different from that observed in the benzene clathrate (Cameron et al, 1982) (Fig. 4d).…”

“…1). The N-C bond lengths in the five groups are not significantly different and have a mean value of 1.466 (7) A, which compares well with 1.466 (3) and 1.467 (2),~ in the CCl 4 and benzene clathrates respectively (Galy et al, 1980;Cameron et al, 1982); the N-C lengths in the sixth group are 1.431 (8) and 1.461 (8)A, which are significantly different. A similar trend in distances is observed in the monoclinic form, but that structure is too ill defined for detailed comparison.…”

“…The conformation that is adopted by the aziridinyl groups is worth examining. In the benzene clathrate the lone pairs of the two geminal aziridinyl groups adopt a cis conformation with the two lone-pair orbitals eclipsed when they are viewed directly along the line joining the two N atoms (Cameron et al, 1982). In this compound, the axes of the lone-pair orbitals are inclined at angles of 96.7 [N(ll) In the aziridinyl groups themselves, five groups have very similar conformations with respect, to the P3Na ring; the sixth group -1~1(21)-C(211)-(~(212) has a different orientation (Fig.…”

“…This compound crystallizes in a number of different forms (Galy, Enjalbert & Labarre, 1980;Cameron, Labarre & Graffeuil, 1982); reported here is the structure of the compound which has been recrystallized from m-xylene to give an orthorhombic form (I) and from carbon disulphide to give a monoclinic form (II).…”

Structures of inorganic rings as antitumor agents. I. Structure of the two allotropic varieties of 1,3,3,5,5-penta(1-aziridinyl)-1λ6,2,4,6,3,5-thiatriazadiphosphorine 1-oxide, (NPaz2)2-(NSOaz)

“…Thus, we could expect that the difference in their melting points would be due to some structural peculiarities, involving either their space groups if the two SOaz are unsolvated in the crystal or an eventual insertion of solvent in the unit cell (clathrate structure): this was indeed observed previously for another anticancer inorganic ring, the hexaaziridinylcyclotri(phosphazene) N3P3az 6, which may either crystallize unsolvated (Cameron et al, 1981), or give clathrates with carbon tetrachloride (N3P3az6.3CCI4) (Galy, Enjalbert & Labarre, 1980) and with benzene (2N3P3az 6.C6H 6) (Cameron, Labarre & Graffeuil, 1982).…”