Crosslinkable branched hydrazones as potential hole transporting materials

Abstract

Such branched hydrazone compounds were synthesized by the reaction of N-2,3-epoxypropyl-N-phenylhydrazones, having heterocyclic or aromatic chromophores R, with different linking agents X, for example, benzenediols or aromatic dimercapto compounds. The molecules of these TM consist of two hydrazone branches linked by the central flexible bridge. The existence of several diastereoisomers, the possibility of intermolecular hydrogen bonding and flexibility of aliphatic linking chains make crystallisation in solid state difficult, so these materials are molecular glasses. Another peculiarity of these TM is the presence of two hydroxyl groups in the molecule. This improves adhesion and compatibility not only with traditional polycarbonate (PC). binder material but also with polyvinylbutyral (PVB). Meanwhile, such branched hydrazone dimers can be chemically crosslinked in the layer, for example, by reaction of the hydroxyl groups with polyisocyanates. These branched hydrazone properties increase the layer stability to bending and stretching of electrophotography belts and the effects of liquid developer. The synthesized TM and compositions with binder exhibit good hole transporting properties and high mobility making them useful for preparation of high sensitivity electro-photographic photoconductors.