Pyridine-2-sulfonates as versatile ligands for the synthesis of novel coordinative and hydrogen-bonded supramolecules

The reactions of 3-methylpyridine-2-sulfonic acid (3-mpSO(3)H) with Cu-II and 4-methylpyridine-2-sulfonic acid (4-mpSO(3)H) with Zn-II in water formed one-dimensional infinite coordination polymers, [Cu(3-mpSO(3))(2)](n) (1) and [Zn(4-mpSO(3))(2)](n) (2). Similarly, two-dimensional hydrogen-bonded supramolecules of stoichiometries, [ML2(H2O)(2)] [L = 3-methylpyridine-2-sulfonate (3-mpSO(3)), M = Mn (3), Fe (4), Co (5), Zn (6); L = 5-methylpyridine-2-sulfonate (5-mpSO(3)), M = Zn (7); L = pyridine-2-sulfonate (PySO3), M = Zn (8); L = 4-mpSO(3), M = Co (9)], [Ni(3-mpSO(3))(2)(H2O)(2)](H2O)-H-. (10) and the one-dimensional hydrogen-bonded network [VO(acac)(3-mpSO(3))(H2O)] (11) (acac = acetylacetonate) have been prepared. The ligands are tridentate [N,O-chelating-Cu-mu-O-bridging] in 1 and 2, while in all the other compounds the N,O-chelating and uncoordinated 0 atoms are engaged in intermolecular hydrogen bonding leading to the formation of hydrogen-bonded networks. The geometry around each metal center is octahedral (9) or distorted octahedral (1-8, 10 and 11). The compounds 3-8, and 10 showed novel pi-pi stacking interactions, not shown by 9 and 11. The magnetic behavior of 3 and 11 indicates lack of any intermolecular magnetic interactions. The position of the substituents in the pyridyl ring and Jahn-Teller effect (Cu-II) appear to determine the stacking interactions as well as the density of ligands with regard to the formation of coordinative and hydrogen-bonded supramolecules. (C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.