Synthesis, spectroscopic characterization, DFT optimization and biological activities of Schiff bases and their metal (II) complexes

Publication date: 5 October 2017
Source:Journal of Molecular Structure, Volume 1145
Author(s): Abdur Rauf, Afzal Shah, Khurram Shahzad Munawar, Abdul Aziz Khan, Rashda Abbasi, Muhammad Arfat Yameen, Asad Muhammad Khan, Abdur Rahman Khan, Irfan Zia Qureshi, Heinz-Bernhard Kraatz, Zia-ur-Rehman
A Novel Schiff base, 3-(((4-chlorophenyl)imino)methyl)benzene-1,2-diol (HL¹) was successfully synthesized along with a structurally similar Schiff base 3-(((4-bromophenyl)imino)methyl)benzene-1,2-diol (HL²). Both the Schiff bases were used to synthesize their zinc (II) and cobalt (II) complexes. These compounds were characterized by FTIR, ¹H NMR, ¹³C NMR and elemental analysis. Metal complexes were confirmed by TGA. Crystals of Schiff bases were also characterized by X-ray analysis and experimental parameters were found in line with the theoretical parameters. Quantum mechanical approach was also used to fine useful structural parameters and to ensure the geometry of metal complexes. The photometric behaviors of all the synthesized compounds were investigated in a wide pH range using BR buffers. The appearance of isosbestic points indicated the existence of Schiff bases in more than one isomeric form. Moreover, these compounds were screened for enzyme inhibition; antibacterial, cytotoxic and in vivo antidiabetic activities and compounds were found active against one or other activity. Results indicate that ZnL22 is a good inhibitor of alkaline phosphatase enzyme and possess highest potential against diabetes, blood cholesterol level and cancer cells. This effort just provides preliminary data for some biological properties. Further investigations are required to precisely determine mechanistic pathways of their use towards drug development.

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