PREPARATION AND PHOTOINDUCED PROCESSES OF FERRIC COMPLEXES CONTAININGFLUORIDE AND TETRADENTATE SALEN-TYPE LIGANDS

Tetradentate open-chain Schiff base ligands R-salen (R-salen are N,N'- ethylenebis(R-salicylideneiminato) dianions) and fluoride anions F- co ordinate to the iron(III) central atom in methanol forming the complex es trans-[Fe(R-salen)(CH3OH)F]. The complexes are redox stable in the dark. Photoexcitation into their intraligand or ligand-to-metal charge transfer excited states leads to the photoreduction of Fe(III) to Fe( II), as a product of metanol oxidation the radical . CH2OH was identif ied. The final products of the redox processes, Fe(II) and CH2O, are f ormed in a 2:1 molar ratio. The efficiency of the photoredox processes is strongly wavelength dependent and influenced by the peripheral gro ups R of the tetradentate ligands. A mechanism of deactivation process es is proposed and the influence of the peripheral groups R on the pho toredox efficiency and electrochemical properties of the complexes is discussed.