Synthesis and structural characterisation of a series of cobalt complexes of N-appended anthracenyl cyclam

The synthesis and structural characterisation of a series of cobalt complexes of 1-(anthracen-9-ylmethyl)-1,4,8,11-tetraazacyclotetradecane (hereafter L2) is described. The complexes, of the type trans-[CoL2X2]+ in which X = Cl−, NCS− and NO2- were synthesised for their use in photoactivated ligand release studies. X-ray crystal structures show that the macrocycle in all three complexes of the series adopts a trans-(III) configuration. Both thiocyanato ligands were found to be N-bound in trans-[CoL2(NCS)2]+ while trans-[CoL2(NO2)2]+ contained both a nitro and nitrito ligand in the one complex. The synthesis of the complex cis-[CoL2(NO2)2]+ from sodium hexanitrocobaltate(III) is also described. This complex also contains both a nitro and nitrito ligand in the one complex, with the cyclam in a cis-(V) arrangement about the metal centre.

Graphical abstractGeometric and linkage isomerism is a feature of a series of anthracenylcyclam cobalt(III) complexes which have been synthesised for future use in photochemical studies.Figure optionsDownload full-size imageDownload as PowerPoint slide