Understanding the excited state dynamics and redox behavior of highly luminescent and electrochemically active Eu(iii)–DES complex

• DOI: 10.1039/d3dt02764c
• Publication Date: 2023-10-28T15:01:56Z
• Authors: Sushil M. Patil; Ruchi Agrawal; Ruma Gupta; Santosh Kumar Gupta; Ayan Ghosh; Sumit Kumar; Kavitha Jayachandran; Tapan K. Ghanty
• Keywords: Europium; Oxidation state

Deep eutectic solvents (DES) are considered a novel class of environmentally benign molecular that as potential for nuclear fuel reprocessing, material recycling, and many other technological applications in both research industry. However, there is complete dearth understanding pertaining to the behavior metal ions DES. Herein, we have investigated speciation, complexation behavior, photochemistry, redox properties tried obtain insight into chemical aspects europium ion DES (synthesized from heptyltriphenylphosphonium bromide decanoic acid). The same has been probed using time-resolved photoluminescence (TRPL), cyclic voltammetry (CV), synchrotron-based extended X-ray absorption fine structure (EXAFS) spectroscopy, density functional theory (DFT) calculations. TRPL indicated stabilization +3 oxidation state, favoring Eu(III)-DES complex emit red light under near UV excitation existence inefficient energy transfer between Eu3+. EXAFS analysis revealed presence Eu-O Eu-Br, which represent local surroundings Eu3+ complex. measurement also suggested two distinct environments DFT calculations supported findings, confirming involves not only oxygen atom acid but atoms nitrate ions, contributing coordination Eu(III). Electrochemical studies demonstrated reaction Eu(III)/Eu(II) displays quasi-reversible behavior. rate was observed increase with higher temperatures. findings this study can contribute fundamental luminescent electrochemically active pave way further development materials enhanced electrochemical properties.