Hydrothermal synthesis and structure determination of Ag3(VVO2){O3P-CH2-PO3} or MIL-42:: a new vanadium(V) methylendiphosphonate inserting silver cations

A new formulated compound, Ag-3((VO2)-O-V){O3P-CH2-PO3} or MIL-42, was synthesized hydrothermally at 170 degreesC. It crystallizes in the monoclinic system (space group P2(1)/n(n degrees 14)) with lattice parameters a = 8.9404(2) Angstrom, b = 8.0226(2) Angstrom; c = 11.7395(1) Angstrom and beta = 100.720(1)degrees, V = 827.32(3) Angstrom (3), Z = 4. Its structure was determined from single crystal X-ray diffraction data (R-1(F-o) = 0.0231, wR(2)(F-o(2)) = 0.0588 for 2126 unique reflections with I greater than or equal to 2 sigma (1)). MIL-42 is three-dimensional with one-dimensional chains of corner linked trimeric units related by sheets of Ag+ in tetrahedral and five-fold coordination. The chains are built up from (VO5)-O-V trigonal bipyramids; one edge of their equatorial plane is chelated by one methylendiphosphonate group. The silver sheets are built up from corner-sharing hexamers in which silver exhibits tetrahedral and five-fold coordination. (C) 2001 Editions scientifiques et medicales Elsevier SAS. All rights reserved.