SYNTHESIS OF POLYMER-SUPPORTED TRIPHENYLPHOSPHINE OXIDE COMPLEXES OF DIVALENT COPPER AND COBALT - A STUDY ON THEIR REACTIVITY WITH SULFUR-DIOXIDE

Polymer-supported triphenylphosphine oxide dihalide and dinitrate comp lexes of copper(II) and cobalt(II), MLnX2 . xH(2)O (L = polystyryl dip henylphosphine oxide; n = 2-4; x = 0-7; X = Cl-, Br- and NO3-) have be en synthesised and characterised. Their reactions with sulfur dioxide have been investigated in the solid state and in toluene slurries at r oom temperature. The absorption of SO2 by these complexes and the free polymeric ligand was also studied by thermogravimetrical analysis (TG A) in the 230-30 degrees C temperature range. All the copper and some cobalt complexes form SO2 adducts on exposure to sulfur dioxide in the solid state at room temperature. When the complexes were exposed to S O2 as toluene slurries, the initial stoichiometry of some complexes wa s found to be modified by the loss of one or two equivalents of neutra l polymeric ligand. TGA studies show that SO2 adducts can only be form ed from initial nitrate complexes. For all nitrate complexes studied, at room temperature (solid state or toluene slurries) and high tempera ture, it was found that nitrate ions were displaced and replaced by su lfate groups. These reactions have been found to be dependent on the m edium of the reaction, on the temperature and on the nature of metal, anionic and neutral ligand. Some air stable SO2 adducts of accurate fo rmulae could be isolated and their infrared spectra have been recorded . Sulfur dioxide desorption of some SO2 adducts has also been studied by heating at 160 degrees C and reduced pressure for 1 h.