Redox‐Controlled Intramolecular Motions Triggered by π‐Dimerization and Pimerization Processes

Kahlfuss, Christophe; Saint‐Aman, Eric; Bucher, Christophe

doi:10.1002/9781118858981.ch3

Cited by 29 publications

(48 citation statements)

References 210 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…From an electrochemical point of view, these dicationic compounds are subject to two consecutive Nernstian electron transfers attributed to the successive formation of the cation radical V +• and neutral quinonic forms V 0 . The growing interest for viologen derivatives in supramolecular chemistry over the past decades thus mainly stems from the acceptor properties of the dicationic V 2+ ‘ground’ state and from the stability of the radical cation state V +• which can both be implemented for the construction of supramolecular assemblies …”

Section: Soluble Supramolecular Assembliesmentioning

confidence: 99%

“…(b), wherein charge repulsion is lowered by the one‐electron reduction of each viologen. This homo‐valent complex involving extensive orbital overlaps between two viologen cation radicals is known as a π‐dimer . Ternary hetero‐caviplexes (1:1:1) are also frequently observed with CB[8], the latter case being illustrated in Fig.…”

Section: Soluble Supramolecular Assembliesmentioning

confidence: 99%

See 1 more Smart Citation

Dynamic supramolecular polymers built from cucurbit[n]urils and viologens

Correia

Chowdhury

Ramos

et al. 2018

Polymer International

Self Cite

View full text Add to dashboard Cite

This review article focuses on supramolecular assemblies involving cucurbit[n]uril‐based containers and viologen guests as key building elements. Cucurbit[n]urils (CB[n], n = 5–8,10) are fascinating hosts forming a wide range of inclusion complexes (caviplexes) with 4,4′‐bipyridinium salts, known as viologens, either as discrete 1:1 inclusion compounds with CB[7] or as ternary inclusion compounds involving two hosts or two guests (2:1 with CB[7] and 1:2 or 1:1:1 with CB[8]). This property is currently being actively exploited to design and prepare self‐assembled dynamic stimuli‐responsive supramolecular polymers including gels, vesicles, films and organized arrays of polymeric microspheres or nanoparticles. This review highlights the main benefits of such polymers and gives an overview of the achievements and progress made in this field over the past decades. © 2018 Society of Chemical Industry

show abstract

Section: Soluble Supramolecular Assembliesmentioning

confidence: 99%

Section: Soluble Supramolecular Assembliesmentioning

confidence: 99%

Dynamic supramolecular polymers built from cucurbit[n]urils and viologens

Correia

Chowdhury

Ramos

et al. 2018

Polymer International

Self Cite

View full text Add to dashboard Cite

show abstract

“…10–13 In recent years, π–π interactions have been incorporated in the design of functional molecular materials featuring tunable optical and conductive properties. 14–19 In biology, π–π interactions between tetrapyrrolic macrocycles are key to numerous electron transfer processes, 20 such as those originating at the bacteriochlorophyll dimer ( special pair ) in bacterial photosynthetic reaction centers. 21, 22 Inspired by the combination of π–π electronic interactions 23 and one-electron redox chemistry in biological tetrapyrroles, the chemistry of π dimers of porphyrin radical cations 24–26 continues to attract considerable attention.…”

Section: Introductionmentioning

confidence: 99%

Interactions of Metal-Based and Ligand-Based Electronic Spins in Neutral Tripyrrindione π Dimers

et al. 2017

View full text Add to dashboard Cite

The ability of tetrapyrrolic macrocycles to stabilize unpaired electrons and engage in π–π interactions is essential for many electron-transfer processes in biology and materials engineering. Herein, we demonstrate that the formation of π dimers is recapitulated in complexes of a linear tripyrrolic analog of naturally occurring pigments derived from heme decomposition. Hexaethyltripyrrindione (H3TD1) coordinates divalent transition metals (i.e., Pd, Cu, Ni) as a stable dianionic radical and was recently described as a robust redox-active ligand. The resulting planar complexes, which feature a delocalized ligand-based electronic spin, are stable at room temperature in air and support ligand-based one-electron processes. We detail the dimerization of neutral tripyrrindione complexes in solution through electron paramagnetic resonance (EPR) and visible absorption spectroscopic methods. Variable-temperature measurements using both EPR and absorption techniques allowed determination of the thermodynamic parameters of π dimerization, which resemble those previously reported for porphyrin radical cations. The inferred electronic structure, featuring coupling of ligand-based electronic spins in the π dimers, is supported by density functional theory (DFT) calculations.

show abstract

“…When the two switching units in 5 and 6 act nearly simultaneously, a sharp difference in delocalization would be realized for the molecular wires. A major issue is inter‐unit interaction, such as electrostatic repulsion, which may interrupt the redox conversion of one unit after another unit is oxidized to the corresponding dication. While both the through‐bond and the through‐space interactions should be considered, the former interaction is less important because X‐ray analysis of 2 2+ (SbCl 6 − ) 2 revealed that the delocalization of positive charges into the main‐chain component was proven to be minimal.…”

Section: Resultsmentioning

confidence: 99%

Molecular Wires with Controllable π‐Delocalization Incorporating Redox‐Triggered π‐Conjugated Switching Units

et al. 2018

View full text Add to dashboard Cite

A perfluorobiphenyl‐2,2′‐diyl dication and its corresponding dihydrophenanthrene‐type electron donor are interconvertible upon two‐electron transfer. Redox‐triggered C−C bond‐formation/cleavage caused a drastic change in the torsion angle of the biphenyl unit. Thus, π‐delocalization ON/OFF switching was observed as a change in the UV absorption upon electrolysis of the linearly extended analogue with two phenylethynyl groups. A further extended π‐system with a molecular length of ca. 3.5 nm, which has two switching units, was synthesized. Spectroelectrograms as well as voltammetric analyses showed that the two units act nearly simultaneously because of the very small inter‐unit electrostatic repulsion in the tetracationic state. Thus, the present pair is a promising candidate as a switching unit for “molecular wires” with controllable π‐delocalization, in which a higher ON/OFF ratio of delocalization could be realized by incorporating multiple switching units.

show abstract

Redox‐Controlled Intramolecular Motions Triggered by π‐Dimerization and Pimerization Processes

Cited by 29 publications

References 210 publications

Dynamic supramolecular polymers built from cucurbit[n]urils and viologens

Dynamic supramolecular polymers built from cucurbit[n]urils and viologens

Interactions of Metal-Based and Ligand-Based Electronic Spins in Neutral Tripyrrindione π Dimers

Molecular Wires with Controllable π‐Delocalization Incorporating Redox‐Triggered π‐Conjugated Switching Units

Contact Info

Product

Resources

About