Synthesis of electroactive hydrazones derived from 3-(10-alkyl-10H-phenothiazin-3-yl)-2-propenals and their corresponding 3,3′-bispropenals

3-(10-Alkyl-10H-phenothiazin-3-yl)-2-propenals and their corresponding 3,3′-bispropenals that represent a previously unexplored class of functionalised phenothiazine derivatives were prepared upon reacting N-alkylated 3-bromo- and 3,7-dibromo-10H-phenothiazines with acrolein diethyl acetal under Pd catalysis. The obtained heterocyclic 2,3-unsaturated aldehydes were condensed with N-methyl-N-phenylhydrazine and N,N-diphenylhydrazine resulting in mono- and dihydrazones that act as effective hole transporting materials. Thermal, optical, electrochemical and photophysical properties of the synthesised new organic electroactive derivatives have been investigated.