Metal phosphonates based on {[(benzimidazol-2-ylmethyl)imino]bis-(methylene)}bis(phosphonic acid):: Syntheses, structures and magnetic properties of the chain compounds [M{(C7H5N2)CH2N(CH2PO3H)2}] (M = Mn, Fe, Co, Cu, Cd)

Five compounds based on 1[(benzimidazol-2-ylmethyl)imino]bis (methylene)bis (phosphonic acid) [(C7H5N2)CH2N(CH2PO3H2)(2)], namely [M{(C7H5N2)CH2N(CH2PO3H)(2)}] [M = Mn (1), Fe (2), Co (3), Cu (4), Cd (5)] have been synthesized under hydrothermal conditions. These compounds are isostructural, crystallizing in the orthorhombic space group Pbca, with a = 15.331(2), b = 10.7150(16), and c = 16.715(2) angstrom for 1; a = 15.320(3), b = 10.477(2), and c = 16.764(3) angstrom for 2; a = 15.207(2), b = 10.4626(16), and c = 16.794(3) angstrom for 3; a 15.101(3), b = 10.3517(17), and c = 16.997(3) angstrom for 4; and a = 15.4679(19), b = 10.8923(13), and c = 16.6175(19) for 5. Each compound shows a one-dimensional chain structure where [MO3N2] trigonal bipyramids are connected by {CPO3} tetrahedra through corner-sharing. The chains are further connected to each other through aromatic stacking of the benzimidazole rings and extensive hydrogen bonds, forming a supramolecular 3D structure. Magnetic susceptibility studies of 1-4 reveal that weak antiferromagnetic interactions occur between the metal centers. (c) Wiley-VCH Verlag GmbH & Co.