A Novel Tris(2-aminoethyl)amine Based Tripodal Ligand: Synthesis and Solution Coordination Studies with Trivalent Iron and Chromium

Abstract

A novel tris(2-aminoethyl)amine (TREN) based tripodal ligand TRENOL (L) has been synthesized and characterized by elemental analysis and UV-VIS, IR, 1H, and 13C NMR spectroscopic methods. The coordination behaviour of the ligand with H+ and trivalent metal ions, Fe(III) and Cr(III), was investigated in aqueous medium at 0.1 M KCl at 25±1°C by potentiometric and spectrophotometric studies. Tripodal ligand showed seven protonation constants in the adopted pH range 2–11 and its electronic spectra exhibited three bands at 216, 323, and 423 nm. Ligand formed various metal complex species of the type MLH5, MLH4, MLH3, MLH, and ML with trivalent metal ions. The determined values of the formation constants (for ML species) of the ligand with Fe(III) and Cr(III) were 24.19 and 18.64, respectively. Molecular modeling studies revealed that the metal complexes formed distorted octahedral geometry. Besides, ligand showed fluorescence at 496 nm when excited at 289 nm. The fluorescence behaviour of the ligand in the presence of Fe(III) ions showed noticeable quenching in comparison to the other metal ions at physiological pH (7.4). So, as per the outcomes of the present study, TRENOL has the potential to be used as the iron detector in environmental, agricultural, and medical fields.

Advances in the Synthesis of Enterobactin, Artificial Analogues, and Enterobactin-Derived Antimicrobial Drug Conjugates and Imaging Tools for Infection Diagnosis

“…245 TRENOL 313 (Figure 9), a similarly imine connected TREN-based analogue bearing a 2,3,4-trihydroxybenzaldehyde chelating unit was also reported by Kanungo and co-workers in 2016. 274 In accordance with the general trend for TREN-based iron chelators, TRENOL 313 showed a much smaller Fe(III) binding constant compared to the natural antetype enterobactin. The compound showed a fluorescence with a maximum emission wavelength of 490 nm, which was quenched This document was downloaded for personal use only.…”

“…in the presence of Fe(III) or Cr(III) upon binding and could therefore be used as fluorescent sensor for the detection of iron. 274 Artificial siderophore backbones structural closely related to TREN are the nitrilotriacetic acid (NTA) and nitrilotripropionic acid (NTP) unit. However, these backbones have so far only been used for a limited number of tripodal enterobactin analogues, bearing different hydroxy-oxopyridines as chelating units (Figure 10).…”

“…245 TRENOL 313 (Figure 9 ), a similarly imine connected TREN-based analogue bearing a 2,3,4-trihydroxybenzaldehyde chelating unit was also reported by Kanungo and co-workers in 2016. 274…”

“…The compound showed a fluorescence with a maximum emission wavelength of 490 nm, which was quenched in the presence of Fe(III) or Cr(III) upon binding and could therefore be used as fluorescent sensor for the detection of iron. 274…”

Inducing Ferrimagnetic Exchange in 1D-FeSe2 Chains Using Heteroleptic Amine Complexes: [Fe(en)(tren)][FeSe2]2

“…27,28 Many tren-based tripod ligands have been employed to design Fe(II) spin crossover complexes. 29,30 Because of its high affinity toward 3d transition metal (TM) cations, tren is also popular in the main group thiometallate chemistry to generate [TM(amine) x ] 2+ complexes. 31−33 Moreover, in polymer synthesis, derivatives of tren have been extensively applied as catalysts for copper-based atom transfer radical polymerization.…”