Four organotin complexes containing furosemide as a ligand (L), Ph3SnL, Me2SnL2, Bu2SnOHL and Bu2SnL2, were synthesized in alcoholic medium.These complexes are:
Dimethyltin di-[4-hloro-2-(furan-2-ylmethylamino)-5-sulfamoylbenzoic acid], Me2SnL2
Dibutyltin di-[ 4-chloro-2-(furan-2-ylmethylamino)-5-sulfamoylbenzoic acid], Bu2SnL2
Dibutyltin hydroxy [4-chloro-2-(furan-2-ylmethylamino)-5-sulfamoylbenzoic acid], Bu2SnOHL
Triphenyltin [4-chloro-2-(furan-2-ylmethylamino)-5-sulfamoylbenzoic acid], Ph3SnL
The ligand and its organotin complexes were characterized by using: FTIR, UV-visible spectroscopy, 1H-NMR, conductivity measurements and melting point. According to the spectral data of the complexes an octahedral geometry was proposed for the Me2SnL2 and Bu2SnL2, while the Ph3SnL and Bu2SnOhL complex has trigonal bipyramid geometry.The synthesized organotin complexes (0.5% by weight) were used as additives to improve the photostability of poly(vinyl chloride), (40 μm thickness) upon irradiation. The photostabilization of poly(vinyl chloride) films were studied at room temperature under irradiation of light( λ= 313)nm wave length with light intensity of 7.75*10-7 Einstein Dm-3 Sec-1.The photostabilization activity of organotin(IV) complexes were determined by monitoring the hydroxyl (IOH) , polyene (Ic=c) and carbonyl (IC=O) indexes, weight loss method with irradiation time. It was found that carbonyl, polyene and hydroxyl indexes values increased with irradiation time and this increase depend on the type of additives. The surface morphology for these films was studied during irradiation time and changes in viscosity average molecular weight of PVC with irradiation time were also tracked. The quantum yield of the chain scission (Φcs) of these complexes in PVC films was also evaluated.The following trend was obtained for the photostabilization effect on PVC films in presence of additives as shown below:
Me2SnL2 < Bu2SnOHL < Bu2SnL2 < Ph3SnL
Increasing the photostability
According to the experimental results obtained several mechanisms were suggested depending on the structures of the organotin complexes. Among these mechanisms, HCl scavenging, UV absorption, peroxide decomposer and radical scavenger for photostabilizer additives.
