Formation of helix-containing rods in a hybrid inorganic–organic material

The novel aluminum ethylenediphosphonate fluoride, [HN(CH2CH2NH3)3][Al2(O3PCH2CH2PO3)2F2]·H2O (1) (monoclinic, P21/n, a=12.145(4) Å, b=9.265(3) Å, c=20.422(6) Å, β=104.952(4)°, Z=3, R1=0.092, wR2=0.196) has been synthesized by solvothermal methods in the presence of tris(2-aminoethyl)amine and its structure determined using single microcrystal X-ray diffraction data. Compound 1 is a one-dimensional extended chain structure composed of well-separated anionic [Al2(O3PCH2CH2PO3)2F2]4− rods containing helical chains of corner-shared cis-AlO4F2 octahedra at their core. The charge-compensating tris(2-aminoethyl)ammonium cations separate the anionic [Al2(O3PCH2CH2PO3)2F2]4− rods that contain either left- or right-handed helical chains. The incorporation of the organic components into this hybrid material has aided the adoption of one-dimensionality by the compound and defined the pitch of the helical AlO4F chain.