Crown-tetrathiafulvalenes attached to a pyrrole or an EDOT unit: synthesis, electropolymerization and recognition properties.

A crown-tetrathiafulvalene electroactive receptor has been covalently linked to electropolymerizable pyrrole or 3,4-ethylenedioxythiophene monomers. The synthetic route to the monofonctionalized tetrathiafulvalene (TTF) ligand has been optimized. Two derivatives of pyrrole (N- and 3-substituted) were synthesized. The various substituted monomers have been electropolymerized to produce polypyrrole (PP) and poly(ethylenedioxothiophene) (PEDOT) films bearing the electroactive TTF moiety. The electroactivity of the polymer films is efficiently controlled by the well-defined two-step redox behavior of the TTF unit. In the case of PEDOT, an alternative post-polymerization derivatization strategy has been used, involving the grafting of the crown-TTF ligand on the previously grown PEDOT backbone. Though chemical derivatization is realized under heterogeneous conditions, in the bulk of the film, this strategy proved to be particularly efficient. These electrodes constitute the first examples of conducting polymer-based modified electrodes incorporating a TTF electrochemical probe, able to interact with a guest ion, such as Ba2+. The cation recognition properties of these various electrodes have been analyzed by cyclic voltammetry and their electroactivity in water as well as their regeneration capability have been investigated.

Does charge carrier dimensionality increase in mixed-valence salts of tetrathiafulvalene-terminated dendrimers?

[structure: see text] In four new dendrimers terminated by 12 electroactive tetrathiafulvalenyl substituents, the tridimensional character of the inter- and intradendrimeric charge and electron transfer, and hence of the electroconductivity, is evidenced by examination of the electronic spectra of their corresponding neutral state and cation radical, dication, and mixed-valence salts, including a closed-shell anion.

Electrochemical recognition of cations by bis(pyrrolo)tetrathiafulvalene macrocycles.

[structure: see text] Tetrathiafulvalene redox-responsive ligands devoid of cis/trans isomerism containing the electroactive bis(pyrrolo[3,4-d])tetrathiafulvalene moiety and polyether subunits have been synthesized. One ligand exhibits high binding affinities for Pb2+ and Ba2+ cations as shown by independent methods (1H NMR, UV-vis spectroscopy, and cyclic voltammetry). The ability of this receptor to electrochemically recognize Pb2+ and Ba2+ is shown by cyclic voltammetry.

Electroregulated Metal-Binding with a Crown Ether Tetrathiafulvalene Derivative: Toward Electrochemically Addressed Metal Cation Sponges.

A redox responsive ligand incorporating the tetrathiafulvalene unit has been synthesized. The crystal structure of the free ligand (Z)-1 (C(20)H(30)O(5)S(8), triclinic P&onemacr;, Z = 2, a = 9.087(6) Å, b = 11.637(7) Å, c = 14.370(8) Å, alpha = 65.54(3) degrees, beta = 82.32(5) degrees, gamma = 84.18(6) degrees, V = 1368 Å(3)) shows the redox-active tetrathiafulvalene core to be essentially planar, which allows observation of two reversible one-electron processes upon electrochemical oxidation. The efficiency of this system in the control of the reversible complexation/expulsion sequence of a metallic cation (i.e., Ba(2+)) has been made possible thanks to a combination of (a) an unprecedented high coordination ability among tetrathiafulvalene-based macrocycles as determined by LSI mass spectrometry (log K degrees = 3.5, NBA-matrix) as well as by solution investigations ((1)H NMR and cyclic voltammetry titration studies), which remarkably converge to similar binding constant values (i.e., log K degrees = 4.2-4.3), and (b) reversible metal cation expulsion upon electrochemical oxidation to the dicationic state. A channel-like solid-state structure is observed for the Ba(2+) complex (C(20)H(30)O(5)S(8), Ba(2+)(CF(3)SO(3))(2)(2-), (H(2)O)(2), CD(3)CN, monoclinic C2/c, Z = 8, a = 45.66(1) Å, b = 8.897(5) Å, c = 23.124(8) Å, beta = 105.54(4) degrees, V = 9050 Å(3)), which results from the segregated stacking mode of the crown ether and the redox-active tetrathiafulvalene subunits, respectively.

A New Dyad Based on C(60) and a Conjugated Dimethylaniline-Substituted Dithienylethylene Donor.

A facile synthesis of the title compound is described, and its optical and electrochemical properties are discussed.