Hydrothermal synthesis, characterization and fluorescence property of a novel layered fluorinated gallium phosphite with heptameric building unit

A new fluorinated gallium phosphite, Ga3F2(2,2'-bipy)(2)(HPO3)(2)(H1.5PO3)(2) 1, which is the first layered gallium phosphite with neutral framework, has been hydrothermally synthesized in the presence of 2,2'-bipyridine (2,2'-bipy) acting as a ligand. The as-synthesized product was characterized by single-crystal X-ray diffraction, powder X-ray diffraction, IR spectroscopy, thermogravimetric analysis (TGA), ICP-AES and elemental analyses and fluorescent spectrum. Single-crystal X-ray diffraction analysis reveals that compound 1 crystallizes in the monoclinic space group C2/c (No. 15) with cell parameters a = 17.633(3) angstrom, b = 9.883(2) angstrom, c = 16.793(3) angstrom, beta = 109.88(3)degrees, V = 2752. 1 (9) angstrom(3) and Z = 4. The construction of two-dimensional (2D)-layered structure in compound I may be viewed as the assembly of heptameric building unit, which is the first to be found in gallium phosphate/phosphite. The heptameric building unit exists in two types of configuration, which alternately connect through oxygen atoms from HPO3 pseudo-pyramids to form a layer with 10-membered ring windows viewed along the a-axis. The adjacent layers are stably packed together and exhibit interesting three-dimensional (3D) supramolecular array via pi-pi interactions of the 2,2'-bipy groups. Additionally, compound 1 shows strong fluorescent property in solid state at room temperature. (c) 2008 Elsevier Inc. All rights reserved.