Redox reaction characteristics of riboflavin: a fluorescence spectroelectrochemical analysis and density functional theory calculation.
Riboflavin (RF), the primary redox active component of flavin, is involved in many redox processes in biogeochemical systems. Despite of its wide distribution and important roles in environmental remediation, its redox behaviors and reaction mechanisms in hydrophobic sites remain unclear yet. In this study, spectroelectrochemical analysis and density functional theory (DFT) calculation were integrated to explore the redox behaviors of RF in dimethyl sulfoxide (DMSO), which was used to create a hydrophobic environment. Specifically, cyclic voltafluorometry (CVF) and derivative cyclic voltafluorometry (DCVF) were employed to track the RF concentration changing profiles. It was found that the reduction contained a series of proton-coupled electron transfers dependent of potential driving force. In addition to the electron transfer-chemical reaction-electron transfer process, a disproportionation (DISP1) process was also identified to be involved in the reduction. The redox potential and free energy of each step obtained from the DFT calculations further confirmed the mechanisms proposed based on the experimental results. The combination of experimental and theoretical approaches yields a deep insight into the characteristics of RF in environmental remediation and better understanding about the proton-coupled electron transfer mechanisms.
Department of Chemistry, University of Science and Technology of China, Hefei 230026, China.
Wei
W
Chen
Department of Chemistry, University of Science and Technology of China, Hefei 230026, China.
Jie-Jie
JJ
Chen
Department of Chemistry, University of Science and Technology of China, Hefei 230026, China.
Rui
R
Lu
Department of Chemistry, University of Science and Technology of China, Hefei 230026, China.
Chen
C
Qian
Department of Chemistry, University of Science and Technology of China, Hefei 230026, China.
Wen-Wei
WW
Li
Department of Chemistry, University of Science and Technology of China, Hefei 230026, China. Electronic address: hqyu@ustc.edu.cn.
Han-Qing
HQ
Yu
D003627:Data Interpretation, Statistical; D004121:Dimethyl Sulfoxide / Q000737:chemistry; D055664:Electrochemical Techniques / Q000379:methods*; D057927:Hydrophobic and Hydrophilic Interactions; D008958:Models, Molecular; D010084:Oxidation-Reduction; D011522:Protons; D012256:Riboflavin / Q000737:chemistry*; D013050:Spectrometry, Fluorescence / Q000379:methods*
D011522:Protons; D012256:Riboflavin; D004121:Dimethyl Sulfoxide
Disproportionation process; Proton coupled electron transfer; Redox chemistry; Riboflavin; Spectroelectrochemistry