The Role of Structural Flexibility in Plasmon‐Driven Coupling Reactions: Kinetic Limitations in the Dimerization of Nitro‐Benzenes. Issue 22 (24th October 2021)

• Record Type: Journal Article
• Authors: Koopman, Wouter; Titov, Evgenii; Sarhan, Radwan M.; Gaebel, Tina; Schürmann, Robin; Mostafa, Amr; Kogikoski, Sergio; Milosavljević, Alexandar R.; Stete, Felix; Liebig, Ferenc; Schmitt, Clemens N.Z.; Koetz, Joachim; Bald, Ilko; Saalfrank, Peter; Bargheer, Matias
• Is Part Of: Advanced materials interfaces. Volume 8:Issue 22(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-10-24
• Subjects: coupling reactions -- density functional theory calculations -- nanoscale heat -- plasmons -- surface‐enhanced Raman spectroscopy; Materials science -- Periodicals; 620.11
• DOI: 10.1002/admi.202101344
• Languages: English
• ISSNs: 2196-7350

Abstract

Abstract: The plasmon‐driven dimerization of 4‐nitrothiophenol (4NTP) to 4‐4′‐dimercaptoazobenzene (DMAB) is a testbed for understanding bimolecular photoreactions enhanced by nanoscale metals, in particular, regarding the relevance of electron transfer and heat transfer from the metal to the molecule. By adding a methylene group between the thiol bond and the nitrophenyl, structural flexibility is added to the reactant molecule. Time‐resolved surface‐enhanced Raman‐spectroscopy proves that this (4‐nitrobenzyl)mercaptan (4NBM) molecule has a larger dimerization rate and dimerization yield than 4NTP and higher selectivity toward dimerization. X‐ray photoelectron spectroscopy and density functional theory calculations show that the electron transfer prefers activation of 4NTP over 4NBM. It is concluded that the rate limiting step of this plasmonic reaction is the dimerization step, which is dramatically enhanced by the additional flexibility of the reactant. This study may serve as an example for using nanoscale metals to simultaneously provide charge carriers for bond activation and localized heat for driving bimolecular reaction steps. The molecular structure of reactants can be tuned to control the reaction kinetics. Abstract : Combining surface‐enhanced Raman‐spectroscopy, X‐ray photoelectron spectroscopy, and density functional theory calculations proves that (4‐nitrobenzyl)mercaptan (4NBM) has a larger plasmon‐induced dimerization rate, dimerization yield, and selectivity toward dimerization than 4‐nitrothiophenol 4NTP because the additional methylene group increases the structural flexibility. In both molecules, the nanoscale metal provides charge carriers for bond activation and localized heat for driving the bimolecular reaction step.