Author :
Amirnasr, Mehdi,Ford, Peter C
Title of Article :
Photochemistry of diacidobis (ethylenediamine)iridium (III) complexes,cis-and trans-Ir(en)2XY**n+. Observations regarding the photoisomerization of d**6 complexes.
Title Of Periodical :
INORGANIC CHEMISTRY
Descriptors :
Photochemistry,Iriduimamine complexes,Photoisomerization
Abstract :
Ligand field excitation of the bis (ethylenediamine)iridium (III) complexes cis- and trans-Ir(en)***2XY***+ (X = Y = C1**-, Br, or I7X=OH-Y = C1**-) in aqueous solution leads to halide photolabilization in each case. For the cis- and trans-dichloro complexes, quantum yields were independent of solution pH, displaying the same values in acidic and basic solutions. In acidic solution,the trans-dihalo complexes undergo photoaquation to give trans-Ir(en)**2(H2O)X**+2 with compete relention and cis-Ir(en)2(H2O)X**2+ with the extent of photoisomerization following the order C1- < I-. In acidic solution,trans-Ir(en)**2(H2O)Cl**2+ is apparently photoinert (H2O exchange excluded)while the cis analogue undergoes photoisomerization to the trans isomer with a modest quantum yield (0.03 mol/einstein). Making solutions of these ions alkaline (pH 12) gives the hydroxo analogues which demonstrate dramtically different photoreaction behavior,cis-lr(en)***2(OH)Cl**+ undergoing Cl**- labilization to give cis-Ir(en)***2(OH)Cl**+ undergoing concomitant photohydrolysis/photoiso-merization to give the same product.These results are interpreted in terms of the model proposed earlier to explain the photostereochemistry of similar rhodium(III) complexes.
Indexer :
1376/09a Shahsvary
