A convenient synthesis of isocyclam and aneN4 and the photophysics of their dicyanochromium(III) complexes
Grisenti, D. L.; Smith, M. B.; Fang, L.; Bishop, N.; Wagenknecht, P. S. A convenient synthesis of isocyclam and aneN4 and the photophysics of their dicyanochromium(III) complexes. Inorg. Chim. Acta 2010, 363, 157-162.
The syntheses of the tetraazamacrocyclic ligands 1,4,7,11-tetraazacyclotetradecane (isocyclam) and 1,5,9,13-tetraazacyclohexadecane (16]aneN4) in two steps starting from the corresponding tetraamine and diethylmalonate is reported. The trans-dicyanochromium(III) complexes, trans-Cr(isocyclam)(CN)2]PF6 and trans-Cr(16]aneN4)(CN)2]PF6 have also been prepared. Both are 2Eg emitters with 0-0 band emission wavelengths at 721.2 and 704.8nm, respectively. The isocyclam complex has a room temperature excited state lifetime of 147Î¼s in aqueous solution which increases to 215Î¼s upon macrocyclic N-H deuteration, whereas the corresponding lifetime of the 16]aneN4 complex is 25Î¼s and is unaffected by macrocyclic N-H deuteration. The implications of the temperature dependence of the excited state lifetimes are also presented.
Inorganica Chimica Acta