Synthesis and Single-Crystal X-ray Characterization of 4,4‘ ‘-Functionalized 4‘-(4-Bromophenyl)-2,2‘:6‘,2‘ ‘-terpyridines

To expand the utility of bis(terpyridine) metal connectivity, the selective symmetrical and unsymmetrical 4,4‘ ‘-functionalization (−CN, −Me, −CO₂Me) of 4‘-(4-bromophenyl)-2,2‘:6‘,2‘ ‘-terpyridines was achieved using the Kröhnke synthesis. The final substituted 2,2‘:6‘,2‘ ‘-terpyridines along with their corresponding intermediates, 4a−c, were recrystallized and characterized by ¹H NMR and ¹³C NMR as well as X-ray crystallography; COSY correlations were also conducted to permit definitive proton assignment.