Publication Details (including relevant citation information):
J. Org. Chem. 2008,73,474-484.
Three new isomeric dipyridoannulenes were synthesized and characterized. These molecules possess differing conjugation pathways between the substituent alkoxy donating groups and the pyridyl acceptor groups. Optical absorption and emission properties of the dipyridoannulenes and their corresponding acyclic precursors were measured and correlated to structural differences and used to evaluate conjugation effectiveness and charge-transfer pathways. Optical properties of protonated dipyridoannulenes were also measured and found to be somewhat insensitive to the degree of protonation. Density functional studies of these systems at the B3LYP/6-31G* level provided insight into their stabilities, polarities, and quinoidal character. An analysis of the **** and LUMO molecular orbitals provided further information regarding charge-transfer behavior. These systems are good metal binding candidates, as the pyridine moiety can act as both an electron-acceptor and a site for metal coordination.