Serre Christian

Hydrothermal synthesis and structure determination of [VF(PO4), N2C2H9] and [Ti(OH)(PO4), N2C2H9], two M(III) phosphates with the ULM-11 bidimensional topology

Abstract [V III F(PO 4 ), en ] and [Ti III (OH)(PO 4 ), en ] ( en = ethylenediamine) are two new layered compounds isostructural with ULM-11. Both were synthesized hydrothermally (453 K, 3 days for ULM-11 (V III ) and 453 K, 28 days for ULM-11 (Ti III )). Structures were determined by single-crystal X-ray diffraction (V III sample) or powder X-ray diffraction (Ti III sample). Both compounds crystallize in the monoclinic system (space group P 2 1 / c ) with cell parameters at 293 K: a = 9.2272 (3) A, b = 7.3532 (2) A, c = 9.8496 (2) A, β = 101.315 (1) °, V = 655.30 A 3 , Z = 4 for the vanadium phase and a = 9.265 (1) A, b = 7.329 (1) A, c = 9.911 (1) A, β = 100.89 (1) °, V = 660.90 A 3 , Z = 4 for the titanium compound. In both lamellar structures, layers consist of chains of MO 3 X 2 N octahedra (M = V, Ti and X = F, OH) related together via PO 4 tetrahedra. One amino group of the diamine is directly bound to the metallic center (via the N atom) while the protonated second amino group points at the interlayer space interacting with terminal P-O groups by strong hydrogen bonds.