Synthesis and reactivity with sulfur dioxide of manganese(II) complexes containing pyridine-N-oxide and 4-methylpyridine-N-oxide as ligands

Abstract

The complexes MnL n X 2(H 2O) m (L = pyridine-N-oxide, 4-methylpyridine-N-oxide; X  Cl, Br, I, NO 3; n = 2−4; m = 0−4) have been prepared. Most of these complexes react with sulfur dioxide in the solid state and as toluene slurries at room temperature, yielding adducts of different stoichiometry, but an increase in the temperature clearly disfavours the interaction. The iodide derivatives of pyridine-N-oxide show the most interesting behaviour, being those which posses the ability of fixing a major quantity of SO 2. The studies of the reversibility of the reaction (desorption studies) show that none of the adducts fix all the SO 2 in a reversible way and more than one binding mode being present for most of the adducts studied here.