Photochemistry of anthracene-appended cobalt(III) cyclam complexes

Abstract

The photochemistry of two anthracene-appended cobalt(iii) cyclam complexes is explored with a view to demonstrate a photoactivated ligand release process. The ligand exchange processes that occur in the complexes cis-[CoL(NO 2)(ONO)]+ and trans-[CoL(NO2)(ONO)]+ in which L = 6-(anthracen-9-ylmethyl)-1,4,8,11-tetraazacyclotetradecane were monitored upon illumination of the anthracenyl chromophore at 360 nm in the presence of a large excess of thiocyanate. The trans-[CoL(NO2)(ONO)] + complex underwent a ligand exchange reaction in the absence of light and displayed an enhancement of the reaction upon illumination. In contrast the cis-[CoL(NO2)(ONO)]+ complex was stable in the dark but displayed..