120th General Meeting of the KCS

Type Poster Presentation
Area Physical Chemistry
Room No. Exhibition Hall 2+3
Time 10월 20일 (금요일) 13:00~14:30
Code PHYS.P-105
Subject Systematic Ligand Modification of TM Complexes for Improved Redox Potentials
Authors FRANCIS KIRBY BURNEA, JONGHYEON LIM, Salimi Abbas1, JIN YONG LEE*
Department of Chemistry, Sungkyunkwan University, Korea
1Department of Chemical Engineering, Sungkyunkwan University, Korea
Abstract An electrolyte with redox potential as high as possible is one of the important properties of an efficient redox flow battery (RFB) material. Many systems have been considered for this application including organometallic complexes. Such systems have the benefit of a metal center that can handle several oxidation states and an organic ligand which can be modified to attain desired increase in reduction potential (E0). In this study, a series of first row transition metal (M = Cr, Mn, Fe, Co, Ni) complexes with known E0 were systematically modified via its ligand by adding electron donating (EDG) and withdrawing (EWG) groups. Using DFT calculations we found that EDG such as –NH2 will cause a negative shift in E0 while EWG have the opposite effect. The overall trend of the calculated E0s according to ligand modifications were predicted to have the order as -NH2 < Pristine < -F ≈ -CN < -NO2. In addition, optimized geometries, LUMO, vertical electron attachment and energy components constituting E0 were discussed in detail to assist the further understanding for E0s. Consequently, we suggested that 16 complexes can play a role as a catholyte in aqueous redox flow battery. Especially, it is expected that [MnLF], [MnLCN] and [NiLNH2] can be used as promising catholyte candidates possibly possessing high E0s which almost reach to the reduction potential limitation 1.25 V in aqueous redox flow battery. Our systematic approach to tune E0 can be applied to the design other complexes via rational ligand modification.
E-mail franciskirby_burnea@yahoo.com