Synthesis, crystal structures, and modifications of novel framework gallium diphosphonates

The framework gallium diphosphonates Ga(2)[O(3)PC(2)H(4)PO(3)](H(2)O)(2)F(2).-2H(2)O (1) (triclinic, P1, a = 5.0432(2) Angstrom, b = 7.2468(3) Angstrom, c = 8.3499(4) Angstrom, alpha = 107.489(2)degrees, beta = 92.444(2)degrees, gamma = 109.338(2)degrees, Z =1) and Ga(2)[O(3)PCH(2)(C(6)H(4))CH(2)PO(3)](H(2)O)(2)F(2) (2) (triclinic, P1, a = 4. 9673(l) Angstrom, b = 7. 0898(2) Angstrom, c = 10. 1220(3) Angstrom, alpha = 92. 698(2)degrees, beta = 93.153(2)degrees, gamma = 109. 122(2)degrees, Z = 1) and the solid-solution series Ga(2){[O(3)PCH(2)(C(6)H(4))CH(2)PO(3)](1-x)(HPO(3))(2x)}(H(2)O)(2)F(2) (0 less than or equal to X less than or equal to 0. 146) x = 0.541 (3) and x = 0.144 Ga(2){[O(3)PCH(2)(C(6)H(4))CH(2)PO(3)](0.853(6))(HPO(3))(0.29(1))}(H(2)O)(2)F(2) (4) (triclinic, P1, a = 4.959(2) Angstrom, b = 7.078(2) Angstrom, c = 10.024(3) Angstrom,alpha = 92.404(5)degrees, beta = 92.955(5)degrees, gamma = 109.187(5)degrees, Z = 1) have been synthesized by solvothermal methods and their structures determined using X-ray diffraction data. All the materials contain linear chains of corner-sharing GaO(4)F(2) octahedra that are linked by the diphosphonate groups to form framework structures. The channels of 1 are found to contain two water molecules per unit cell while those in 2 are too narrow to contain extraframework species. The apertures created in the phosphite-substituted derivatives of 2 (3 and 4) are shown, by crystallographic methods, to be considerably larger than those in 2 and, by thermogravimetric methods, to create more open structures. The synthetic conditions or form of the diphosphonate group are found to play a defining role in the adoption of this particular configuration of the inorganic component in the reported compounds and provide an additional strategy for the rational design of framework hybrid organic -inorganic solids.