Synthesis, spectroscopic characterization, X-ray crystal structure, antimicrobial, DNA-binding, alkaline phosphatase and insulin-mimetic studies of oxidovanadium(IV) complexes of azomethine precursors
Khurram Shahzad Munawar, Saqib Ali, Muhammad Nawaz Tahir, Nasir Khalid, Qamar Abbas, Irfan Qureshi, Shabbir Hussain, Muhammad Ashfaq
Abstract
A series of novel azomethine precursors were synthesized by the condensation reactions of 3-(trifluoromethyl)benzenamine (tfmb) with 2-hydroxybenzaldehyde (HL1) (tfmbs), 2,3-dihydroxybenzaldehyde (HL2) (tfmbdh), 2-hydroxy-1-naphthaldehyde (HL3) (tfmbnd) and 5-chloro-2-hydroxybenzaldehyde (HL4) (tfmbCl). The oxidovanadium(IV) complexes of the type [VO(tfmbs)2] (1), [VO(tfmbdh)2] (2), [VO(tfmbnd)2] (3) and [VO(tfmbCl)2] (4) were also prepared by the reaction of ligands HL1–HL4 with vanadyl(V) isopropoxide [VO(OCHMe2)3]. The synthesized compounds were characterized by elemental analysis, FT-IR, multinuclear (1H and 13C) NMR spectroscopies, magnetic susceptibility measurements and thermogravimetry. The studies revealed that binding of precursors with metal took place through azomethine nitrogen and phenolic oxygen. The single-crystal analysis of HL1, HL4 and 3 has been carried out. The intercalation mode of interaction of the complexes with Salmon sperm DNA (SS-DNA) was established by the observed hypochromicity through UV–vis spectroscopic studies. The determined negative ΔG values confirmed the spontaneity of the binding process of complexes with SS-DNA. All the synthesized precursors and complexes were screened for their alkaline phosphatase inhibition, antimicrobial, hemolytic and insulin-mimetic properties, which exhibited significant activities with a few exceptions.