The practical synthesis of two new classes of polytopic azole-based ligands is reported.
The synthesis of the precursor amines was achieved by substitution of a leaving group
by an azide followed by reduction with triphenylphosphine and water. Another efficient
method employs a Mitsunobu coupling with phthalimide allowing the conversion of a
primary alcohol into a primary amine. The triazole and tetrazole were obtained by
cyclization of these amine precursors. The first family consisted of ditopic ligands
containing both 1-R-tetrazole and 4-R-1,2,4-triazole moieties linked by an alkyl spacer,
while the second consists of branched ligands with three azole cycles linked to a
benzene core through ether bonds. Both classes are suitable for building multidimensional
polynuclear coordination assemblies and for the observation of thermal spin state
crossover behavior with iron(II) ions.
ligands - heterocycles - Mitsunobu reaction - coordination chemistry
