Dendrimers as Multielectron Storage Devices

Ceroni, Paola; Venturi, Margherita

doi:10.1002/9780470583463.ch6

Cited by 14 publications

(4 citation statements)

References 119 publications

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“…Again, the measured current is seen to be much larger for the nanostructured biosensor than for the Pt electrode without NWs. If electron transfer at the electrode has no diffusive components, the peak current (i p ) is given by equation (4) [15,16],…”

Section: Discussionmentioning

confidence: 99%

Glucose biosensor based on functionalized ZnO nanowire/graphite films dispersed on a Pt electrode

et al. 2016

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We present a glucose biosensor based on ZnO nanowire self-sustained films grown on compacted graphite flakes by the vapor transport method. Nanowire/graphite films were fragmented in water, filtered to form a colloidal suspension, subsequently functionalized with glucose oxidase and finally transferred to a metal electrode (Pt). The obtained devices were evaluated using scanning electron microscopy, energy-dispersive x-ray spectroscopy, cyclic voltammetry and chronoamperometry. The electrochemical responses of the devices were determined in buffer solutions with successive glucose aggregates using a tripolar electrode system. The nanostructured biosensors showed excellent analytical performance, with linear response to glucose concentrations, high sensitivity of up to ≈17 μA cm(-2) mM(-1) in the 0.03-1.52 mM glucose concentration range, relatively low Michaelis-Menten constant, excellent reproducibility and a fast response. The detection limits are more than an order of magnitude lower than those achievable in commercial biosensors for glucose control, which is promising for the development of glucose monitoring methods that do not require blood extraction from potentially diabetic patients. The strong detection enhancements provided by the functionalized nanostructures are much larger than the electrode surface-area increase and are discussed in terms of the physical and chemical mechanisms involved in the detection and transduction processes.

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Section: Discussionmentioning

confidence: 99%

Glucose biosensor based on functionalized ZnO nanowire/graphite films dispersed on a Pt electrode

et al. 2016

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“…By virtue of their reduction properties they are suited to artificial systems developed for solar energy conversion, both in bimolecular schemes and in supramolecular (multicomponent) arrangements in which they play the role of electron acceptors (i.e., electrophores) . Their mild and reversible reduction processes also make them choice components in supramolecular assemblies designed to behave as electron-storage systems (e.g., polyviologen dendrimers) , or molecular machines , whose organization and machinery are based on charge-transfer interactions and redox inputs, respectively. , …”

Section: Introductionmentioning

confidence: 99%

Designing Multifunctional Expanded Pyridiniums: Properties of Branched and Fused Head-to-Tail Bipyridiniums

et al. 2010

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The multifaceted potentialities of expanded pyridiniums (EPs), based on one pyridinium core bearing a 4-pyridyl or 4-pyridylium as the N-pyridinio group, are established at both experimental and theoretical levels. Two classes of head-to-tail (htt) EPs were designed, and their first representative elements were synthesized and fully characterized. The branched (B) family is made up of 2,6-diphenyl-4-aryl-1,4'-bipyridin-1-ium (or 1,1'-diium) species, denoted 1B and 2B for monocationic EPs (with aryl = phenyl and biphenyl, respectively) and 1B(Me) and 2B(Me) for related quaternarized dicationic species. The series of fused (F) analogues comprises 9-aryl-benzo[c]benzo[1,2]quinolizino[3,4,5,6-ija][1,6]naphthyridin-15-ium species, denoted 1F and 2F, and their 2,15-diium derivatives referred to as 1F(Me) and 2F(Me). Electrochemistry (in MeCN vs SCE) reveals that branched EPs undergo a single reversible bielectronic reduction at ca. -0.92 V for 1B/2B and -0.59 V for 1B(Me)/2B(Me), whereas pericondensed species show two reversible monoelectronic reductions at ca. -0.83 and -1.59 V for 1F/2F and ca. -0.42 and -1.07 V for 1F(Me)/2F(Me). Regarding electronic absorption features, all htt-EP chromophores show absorptivity in the range of ca. 1-4 × 10(4) M(-1) cm(-1), with red-edge absorptions extending toward 450 and 500 nm (in MeCN) for 2B(Me) and 2F(Me), respectively. These lowest-energy pi-pi* transitions are ascribed to intramolecular charge transfer between the electron-releasing biphenyl group and the htt-bipyridinium electron-withdrawing subsystems. EPs display room-temperature photoemission quantum yields ranging from 10% to 50%, with the exception of 1B, and branched luminophores are characterized by larger Stokes shifts (8000-10 000 cm(-1)) than fused ones. Lastly, a method to predict the efficiency of photobiscyclization of branched EPs into fused ones, based on the analysis of computed difference maps in total electron density for singlet excited states, is proposed.

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“…Dimerization of the viologen units following electron transfer allows stabilization of the charge in the materials. ,− The reduced particles are highly stable and can be stored more than 1 year without any modification. Thus, ZnL n colloids have the ability to store and release multielectrons and could be employed in multielectron storage devices with utilization as redox sensors, molecular batteries, or mediators for redox catalysts with multielectron processes. ,,− Compared to small organic molecules and dendrimers designed for charge-storage applications, ZnL n particles overcome challenges such as chemical and morphological stability and their colloidal dimensions allow easy separation and size selectivity. Among the very rare examples of colloidal particles incorporating viologen units designed for charge-storage purposes, ZnL n particles are distinguished by their single-step preparation process in an aqueous solvent and by their high density in viologen units due to crystalline organization.…”

Section: Discussionmentioning

confidence: 99%

Redox-Responsive Colloidal Particles Based on Coordination Polymers Incorporating Viologen Units

et al. 2020

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Colloidal particles based on supramolecular polymers are emerging as promising functional materials because of their intrinsic dynamic features and the possibility of stimuli responsivity. In this work, ≈200 nm self-assembled redoxresponsive colloidal particles made of 1D-coordination polymers were readily prepared. In these metallopolymers, organic entities made of bis(viologen) groups covalently associated with terpyridine units are spontaneously bridged by Zn 2+ cations through the formation of coordination bonds. The properties of these particles were analyzed and their redox activities investigated. Upon reduction of the viologen units, the formation of π-dimers between the reduced viologen moieties was demonstrated by spectroscopic experiments. It was shown that intermolecular π-dimers (i.e., between different polymer chains) that do not exist in homogeneous polymer solutions were, nevertheless, formed in the particle's structure because of the effects of confinement. The presence of these π-dimers allows stabilization of the charge in the colloids.

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Dendrimers as Multielectron Storage Devices

Cited by 14 publications

References 119 publications

Glucose biosensor based on functionalized ZnO nanowire/graphite films dispersed on a Pt electrode

Glucose biosensor based on functionalized ZnO nanowire/graphite films dispersed on a Pt electrode

Designing Multifunctional Expanded Pyridiniums: Properties of Branched and Fused Head-to-Tail Bipyridiniums

Redox-Responsive Colloidal Particles Based on Coordination Polymers Incorporating Viologen Units

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