Hydrothermal synthesis and characterisation of BIS (4- Hydroxybenzaldehyde) - P - Phenylenediamine zinc (ii) phosphate
The condensation of a para-phenylenediamine and two equivalent of para-hydroxybenzaldehyde in the presence of Zn2+ ions yielded a metallo-ligand of composition [ZnL2Ph(NH3)2(H2O)2] I. Compound I melts at 126oC and is soluble in common organic solvents such as ethanol (C2H5OH), dimethylformamide (DMF) and dimethylsulphoxide (DMSO). The scanning electron micrograph of compound I reveals a rectangular block crystals. The metalloligand synthesized was reacted with ortho-phosphoric acid under hydrothermal conditions at 105oC to obtain colourless crystals of compound II with composition [Zn4L2(HPO4)6(H2O)3]. Compound II is insoluble in common organic solvents and melts above 300oC. The structure of compounds I and II have been studied with the help of Infrared and UV- visible spectroscopy. The complexes show broad band absorption in the region 3760 – 3765.71 cm-1 due to the symmetric stretching vibration of the co-ordinated water molecule.
Keywords: Hydrothermal reaction, metalloligand, parahydroxybenzaldehyde, para-phenylenediamine, zinc phosphate.