On the Supra-LUMO Interaction: Case Study of a Sudden Change of Electronic Structure as a Functional Emergence

0549128 - ÚFCH JH 2022 RIV DE eng J - Journal Article
Gosset, A. - Nováková Lachmanová, Štěpánka - Cherraben, S. - Bertho, G. - Forte, J. - Perruchot, Ch. - de Rouville, H.-P. J. - Pospíšil, Lubomír - Hromadová, Magdaléna - Bremond, E. - Lainé, P. P.
On the Supra-LUMO Interaction: Case Study of a Sudden Change of Electronic Structure as a Functional Emergence.
Chemistry - A European Journal. Roč. 27, č. 71 (2021), s. 17889-17899. ISSN 0947-6539. E-ISSN 1521-3765
R&D Projects: GA ČR(CZ) GA21-13458S; GA MŠMT(CZ) 8J21FR016
Institutional support: RVO:61388955
Keywords : potential sweep voltammetry * charge-transfer * redox * chemistry * electrochemistry * serendipity * complexity * pyridinium * parameters * transfers * electronic structure * electrostatic interactions * pyridinium * structure-activity relationships * supramolecular electrochemistry
OECD category: Electrochemistry (dry cells, batteries, fuel cells, corrosion metals, electrolysis)
Impact factor: 5.020, year: 2021
Method of publishing: Limited access

The synergistic functioning of redox-active components that emerges from prototypical 2,2 '-di(N-methylpyrid-4-ylium)-1,1 '-biphenyl is described. Interestingly, even if a trans conformation of the native assembly is expected, due to electrostatic repulsion between cationic pyridinium units, we demonstrate that cis conformation is equally energy-stabilized on account of a peculiar LUMO (SupLUMO) that develops through space, encompassing the two pyridiniums in a single, made-in-one-piece, electronic entity (superelectrophoric behavior). This SupLUMO emergence, with the cis species as superelectrophore embodiment, originates in a sudden change of electronic structure. This finding is substantiated by insights from solid state (single-crystal X-ray diffraction) and solution (NOE NMR and UV-vis-NIR spectroelectrochemistry) studies, combined with electronic structure computations. Electrochemistry shows that electron transfers are so strongly correlated that two-electron reduction manifests itself as a single-step process with a large potential inversion consistent with inner creation of a carbon-carbon bond (digital simulation). Besides, absence of reductive formation of dimers is a further indication of a preferential intramolecular reactivity determined by the SupLUMO interaction (cis isomer pre-organization). The redox-gated covalent bond, serving as electron reservoir, was studied via atropisomerism of the reduction product (VT NMR study). The overall picture derived from this in-depth study of 2,2 '-di(N-methylpyrid-4-ylium)-1,1 '-biphenyl proves that trans and cis species are worth considered as intrinsically sharply different, that is, as doubly-electrophoric and singly-superelectrophoric switchable assemblies, beyond conformational isomerism. Most importantly, the through-space-mediated SupLUMO may come in complement of other weak interactions encountered in Supramolecular Chemistry as a tool for the design of electroactive architectures.
Permanent Link: http://hdl.handle.net/11104/0325145