Oxyfluorinated compounds with an open framework XX. Synthesis and structural characterization of aza-crown ether templated Ga 5F 2(HPO 4) 2(PO 4) 4,C 12H 27N 6 (MIL-1)

Abstract

A new monoclinic [space group: C2/m (no. 12)] fluorinated gallium phosphate Ga 5F 2(HPO 4) 2(PO 4) 4,C 12H 27N 6, a = 8.6552(6) Å, b= 16.4521 (14) Å, c= 11.9391(8) Å, β= 102.993(7), V= 1656.6(2) Å 3, Z = 2, has been hydrothermally synthesized (180 °C, 24 h, autogenous pressure), in the presence of an aza-crown ether, hexacyclen trisulfate, C 12H 30N 6 6−,3SO 4 2− (1,4,7,10,13,16-hexaazacyclooctadecane = A 618-Crown-6). as a structural agent. It exhibits an open-framework structure which consists of layers built up from the corner sharing of GaO 4, GaO 4F, GaO 4F 2 and PO 4 polyhedra, the layers being linked together by HPO 4 groups in order to form a three-dimensional network, with 12-ring channels along the [100] direction and 8-ring channels along the [001] direction. The A 618-Crown-6 molecule, delocalized on two positions, is located in the larger channels. 31P MAS NMR spectrometry indicated a statistical site distribution for the interlayer HPO 4 groups.