Synthesis, characterization and structure determination of Mu-15: a new fluorogallophosphate with fluoride as a specific template of the D4R units

The title compound (Mu-15) is a new three-dimensional fluorinated gallophosphate synthesized from an aqueous fluoride-containing medium, using N,N,N',N'-tetramethyl-1,3-propanediamine (TMP) as organic template. This material was characterized by XRD, SEM, thermal analysis and solid-state NMR spectroscopy (C-13, F-19, P-31, Ga-71). The structure of Mu-15 ([Ga16P16O60(OH)(2)F6O4][H2TMP](4)) was determined from XRD powder data. It crystallizes in the space group Pna2(1) [a = 16.5779(2), b = 9.8223(1), c = 13.8562(2) Angstrom, V = 2256.25(6) Angstrom(3)] and consists of an arrangement of double-four-ring units (D4R) hosting F- anions. The connection of these units leads to a three-dimensional but interrupted framework, with two types of channels. The first, parallel to the [100] direction, is delimited by 10-ring apertures, whereas the second channel system, parallel to the [010] direction, is characterized by 8-ring openings. This fluorogallophosphate is another example showing the structure-directing role of F- towards the D4R units.