STRUCTURAL, DSC, AND IR STUDIES ON A NEW ORGANIC CATION CYCLOHEXAPHOSPHATE - 3-(CH2)(2)-NH2-(CH2)(2)-NH3]2P6O18-CENTER-DOT-2H2O

Chemical preparation, calorimetric studies, crystal structure, and IR absorption spectra are given for a new organic cyclohexaphosphate. The aza-3 pentanediyl-1,5 dihydrate, [NH3-(CH2)(2)-NH2-(CH2)(2)-NH3]2P6O1 8 . 2H2O is triclinic P (1) over bar with unit cell dimensions, a = 8. 709(2), b = 9.729(2), c = 9.145(2) Angstrom, alpha 99.11(2)degrees, be ta = 110.70(2)degrees, gamma 67.19(2)degrees, and Z = 1, V = 667.9(6). Angstrom(3), rho(m) = 1.72 g.cm(-3), mu = 0.268 mm(-1). The refinemen t of data, collected at room temperature, leads to a final R = 0.035 f or 3844 independent reflections. The P6O18 ring anion is centrosymmetr ic and significantly distorted with P-P-P angles varying from 93.6 deg rees to 134.8 degrees as commonly observed for such rings with (1) ove r bar internal symmetry. A three-dimensional network of strong hydroge n bonds interconnects the structural arrangement. Of the eight hydroge n atoms in the organic group, seven are connected to the external oxyg en atoms of four phosphoric rings and form a complex anion of formula [C4N3H16(P6O18)4](-21); the remaining one establishes a hydrogen bond with a water molecule which links, with the help of its proper hydroge n atoms, successive complex anions. The hydrogen bonding geometries ar e discussed. (C) 1995 Academic Press, Inc.