Regioselective Synthesis of V‑Shaped Bistriazinyl-phenanthrolines

A new,
regioselective synthesis of V-shaped 2,9-bis­(6-(4-halophenyl)-1,2,4-triazin-3-yl)-1,10-phenanthrolines
(4XPhBTPhen) ligands was developed, creating access to a simple and
reliable synthesis of precursors for future supramolecular actinide
complexing systems. Described is a reactant-directed regioselective
synthetic method, which was found to be high yielding and reliable
and yields exclusively 6,6′-phenyl BTPhen derivatives (including
4-chloro and 4-bromo) in five simple steps. Molecular and crystal
structures of PhBTP and PhBTPhen products are fully determined and
both were found to be in space group C2/c. Additionally, molecular and crystal structures of Z and E isomers of 2-hydrazono-2-phenylacetaldehyde
oxime, a reagent in the synthetic route, reveal existence of strong
intramolecular N–H···O hydrogen bonding in the Z isomer explaining its lower solubility in water.