Synthesis, spectroscopic characterization, insulin-enhancment, and competitive DNA binding activity of a new Zn(ii) complex with a vitamin B6 derivative—a new fluorescence probe for Zn(ii)

Abstract

This paper describes the activity of a Schiff base ligand, derived from pyridoxal, as a promising fluorescence probe for biologically important Zn(II) ion sensing. This is the first report of a vitamin based ligand as a fluorescent probe for sensing Zn(II) ions. The Schiff base H 2 pydmedpt, derived from the condensation of pyridoxal ( pyd) and N,N-bis[3-aminopropyl]methylamine (medpt), exhibits around a 325-fold increase in fluorescence quantum yield due to zinc triggered fluorescence switching. The response is specific for Zn(II) ions, and remains unaffected by the presence of alkali and alkaline earth metals but is suppressed to varying degrees by transition metal ions. The corresponding Zn(II)-complex, [Zn( pydmedpt], is isolated. The DFT optimized structure of the complex is compatible with elemental analysis, mass spectrometry, FT-IR, electronic and NMR spectra. The isolated complex, having pK a values of ∼5.3 and ∼5, is a moderate intercalator for DNA with an apparent binding constant of 2.3 × 10 6 M −1 . The complex also shows insulin-enhancing activity at par with other reported complexes, with an IC 50 value of 0.65 with respect to ZnSO 4 . † Electronic supplementary information (ESI) available. See

[N′-(2-Hydroxy-3-methoxybenzylidene)-2-methoxybenzohydrazonato](quinolin-8-olato)oxovanadium(V): Synthesis, Crystal Structure and Thermal Property

“…The presence of vanadium(IV) and vanadium(V) compounds in many vanadium-dependent enzymes, for instance, nitrogenases and haloperoxidases, [1][2][3] as well as insulin mimicking, [4,5] have stimulated the search for structural and functional models based on vanadium complexes. Moreover, oxovanadium complexes have been attracted tremendous attention for their versatile catalytic properties in organic synthesis.…”

Thirty years through vanadium chemistry

“…The compounds prepared are slightly to moderately soluble in water and the order of stability of the complexes formed is pyridoxamine b H 2 pyr 2 en b H 2 pyr 2 an. Pyridoxal and pyridoxamine are forms of Vitamin B 6 and are non-toxic metabolites and this work promoted the start of many other studies involving pyridoxal Schiff base (pyr 2 en) and reduced Schiff base derivatives (pyr 2 an) by several groups including ours [155][156][157][158][159].…”

“…[154] were published, either for the preparation and use of vanadium complexes or of other metal ions. As mentioned Schiff bases and reduced Schiff bases derived from pyridoxal have the advantage of being more compatible with solvents containing water, thus they were proposed either as ligands for the preparation of complexes with potential pharmaceutical use, or for homogeneous or supported catalytic systems to be used with water containing solvents [155][156][157][158][159].…”

Synthesis, Crystal Structure, and Thermal Property of [N′-(2-hydroxy-3-methoxybenzylidene)-2-methoxybenzohydrazonato](methanol)(methoxy)oxovanadium(V)

“…The presence of vanadium(IV) and vanadium(V) compounds in many vanadium-dependent enzymes, [1][2][3] as well as insulin mimicking, [4,5] have stimulated the search for structural and functional models based on vanadium complexes. In addition, oxovanadium complexes have been attracted much attention for their versatile catalytic properties in organic preparation.…”