Synthesis, spectroscopic characterization, X-ray crystal structure, antimicrobial, DNA-binding, alkaline phosphatase and insulin-mimetic studies of oxidovanadium(IV) complexes of azomethine precursors

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.

Graphical abstract

Keywords:

• Oxidovanadium(IV) complexes
• crystal structure
• DNA-binding
• insulin-mimetic studies
• antimicrobial activity
• alkaline phosphatase inhibition

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Higher Education Commission under Indigenous 5000 Program [PIN NO. 106-1087-ps6-016].