Synthesis, Spectral Characterization and Electrochemistry of Vanadium(v) Complex With Tryptophan

Abstract

A new oxovanadium(V) complex of NH 4 VO 3 and tryptophan (TrpH) has been synthesized in aqueous solution at pH 6.0 and characterized by elemental analysis, UV-Vis, FT-IR, 1 H-NMR and mass spectroscopic data. The complex (Na 4 [V 3 O 9 (Trp)]) was diamagnetic in nature as was evident from the electron spin resonance spectroscopy (ESR) and the magnetic susceptibility measurements, in conformity with the presence of vanadium(V) in the structure. The electrochemical behaviour of Na 4 [V 3 O 9 (Trp)] complex was also studied on the hanging mercury drop electrode (HMDE) by using cyclic voltammetry (CV). The cyclic voltammograms of Na 4 [V 3 O 9 (Trp)] complex exhibit two new reduction waves at -0.38 V and -1.01 V in Britton-Robinson buffer (pH 6.0) for the potential range from 0.0 V to -1.2 V.

Synthesis, Characterization, and In Vitro Insulin-Mimetic Activity Evaluation of Valine Schiff Base Coordination Compounds of Oxidovanadium(V)

“…The vanadium-based compounds formation is confirmed both by the hypsochromic (blue) shift of about 52 ÷ 61 nm between the λ max of benzaldehyde derivative precursors (λ max = 326 nm for salicylaldehyde and λ max = 348 nm of o-vanillin, respectively) and the second band of the complexes (274 nm for 1a/1b and 287 nm for 2a/2b) and by the appearance of a third band at λ max = 371 nm for 1a/1b and λ max = 391 nm for 2a/2b, which can be assigned to the charge transfer (CT) from ligand to metal (LMCT), namely from double bond oxygen (V = O) to the vanadium atom (O → V) in both 1a/1b (V V , d 0 ) and 2a/2b (V V , d 0 ) (Figure 2A,B and Supplementary Figure S1A,B). Similar to the solutions of many other vanadate(V) species and vanadium(V) bound to oxygen donor ligands, our complexes give a yellow color in PBS (pH 7.4) solution, which is primarily due to the intense LMCT bands tailing from the UV region [35]. The CD spectra of the 5 × 10 −4 Μ vanadium compounds solutions and 2 × 10 -2 M L-/D-valine (PBS, pH 7.4), recorded between the 200 ÷ 500 nm range, are presented in Figure 2C,D, and Supplementary Figure S2.…”

“…Electronic spectral data of 1 × 10 −4 M 1a, 1b, 2a, and 2b complexes in PBS, pH 7.4. 232, 233 nm): π → π* transition of the benzene ring and charge-transfer transitions[13], 2nd band (274, 287 nm): the π → π* transitions of the benzene ring[33] and to imino (-CH = N-) group coordination[34], 3rd band (371, 391 nm): probably due to the O → V CT 1 from double bond oxygen to the vanadium atom[35].…”

Synthesis and stability of L-tryptophan adsorbed on Ti/MCM-41 as a catalyst for the regioselective aminolysis of styrene oxide

“…A sharp peak at 3404 cm À1 corresponds to the absorption of the asymmetric vibration band due to the indole (eNH) moiety of L-tryptophan [50]. weak and diffuse.…”

Synthesis, Characterization and DFT Calculations of Schiff-Base Vanadium(v) Complexes Derived From Salicyldehyde With 1,2-Diaminopropane or 2-Picolylamine

“…The free ligands L1 and L2 characteristic stretching vibration bands appear at 1635 and 1629 cm -1 corresponding to the C=N vibration [18][19][20][21], which are shifted to 1629 and 1624 cm -1 in their complexes C1 and C2, respectively indicating coordination of the nitrogen to vanadium [18][19][20][21]. The broad vibration bands above 3000 cm -1 characteristic of the stretching frequencies of H-bonding OH groups.…”