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The typical design of chiral electroactive materials involves attaching chiral pendants to an electroactive polyconjugated backbone and generally results in modest chirality manifestations. Discussed herein are electroactive chiral poly-heterocycles, where chirality is not external to the electroactive backbone but inherent to it, and results from a torsion generated by the periodic presence of atropisomeric, conjugatively active biheteroaromatic scaffolds, (3,3'-bithianaphthene). As the stereogenic element coincides with the electroactive one, films of impressive chiroptical activity and outstanding enantiodiscrimination properties are obtained. Moreover, chirality manifestations can be finely and reversibly tuned by the electric potential, as progressive injection of holes forces the two thianaphthene rings to co-planarize to favor delocalization. Such deformations, revealed by CD spectroelectrochemistry, are elastic and reversible, thus suggesting a breathing system., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A family of highly stable (poly)perfluoroalkylated metallic nitride cluster fullerenes was prepared in high-temperature reactions and characterized by spectroscopic (MS, (19)F NMR, UV-vis/NIR, ESR), structural and electrochemical methods. For two new compounds, Sc(3)N@C(80)(CF(3))(10) and Sc(3)N@C(80)(CF(3))(12,) single crystal X-ray structures are determined. Addition pattern guidelines for endohedral fullerene derivatives with bulky functional groups are formulated as a result of experimental ((19)F NMR spectroscopy and single crystal X-ray diffraction) studies and exhaustive quantum chemical calculations of the structures of Sc(3)N@C(80)(CF(3))(n) (n = 2-16). Electrochemical studies revealed that Sc(3)N@C(80)(CF(3))(n) derivatives are easier to reduce than Sc(3)N@C(80), the shift of E(1/2) potentials ranging from +0.11 V (n = 2) to +0.42 V (n = 10). Stable radical anions of Sc(3)N@C(80)(CF(3))(n) were generated in solution and characterized by ESR spectroscopy, revealing their (45)Sc hyperfine structure. Facile further functionalizations via cycloadditions or radical additions were achieved for trifluoromethylated Sc(3)N@C(80) making them attractive versatile platforms for the design of molecular and supramolecular materials of fundamental and practical importance.

In situ spectroelectrochemistry is of high importance for the characterization of doping reactions in pi-conjugated polymers. In this paper we present the results of simultaneous ESR and UV-vis-NIR measurements performed in situ during electrochemical p- and n-doping of polyazulene (PAz). In previous studies on p-doping of PAz the assignment of the optical absorption bands to specific charge carriers have been somewhat controversial, therefore the aim of this study is to clarify the nature of the doping-induced charge carriers and their corresponding optical absorption bands by in situ ESR-UV-vis-NIR spectroelectrochemistry. PAz was polymerized in two different potential ranges in order to obtain films with different structures and morphologies. On the basis of our spectroelectrochemical results we propose that polarons and polaron pairs are formed during p-doping in the two different types of PAz films electrodeposited on ITO. For studying n-doping of PAz, a Pt electrode was used. The ESR signal first decreased in intensity at low doping levels and then increased in intensity at higher doping levels pointing to the formation of new paramagnetic species. At high negative potentials there occurred an additional line broadening of the ESR signal indicating the existence of rather localized negative charge carriers.

Electrochemical nanostructuring of ordered C60 fullerene layers in aqueous solution was studied by in situ Raman spectroelectrochemistry. A completely changed molecular film structure was found for nanostructured films. C60 polymers/oligomers and hydrogenated C60 were identified as the main fullerene structures after nanostructuring. No significant contributions of Ax C60 fullerides (A=alkaline metal; x=1, 3, 6) were found. [ABSTRACT FROM AUTHOR]

The doping level of spin-coatedpoly(ethylenedioxythiophene):poly(styrenesulfonate) (PEDT:PSS) films was adjusted quantitatively by an electrochemical doping/dedoping process in toluenesulfonic acid containing solution. The increase in doping level leads to an improvement of hole injection from the PEDT:PSS/ITO (indium--tin oxide) anode to the hole transporting layer, which is attributed to the enhanced work function of PEDT. The performance of vapor-deposited tri(8-hydroxyquinoline) aluminum (Alq[SUB3]) based organic light-emitting devices with these anodes is shown to depend strongly on the doping level of PEDT:PSS. The device, built on a highly oxidized anode by electrochemical modification (electrochemical equilibrium potential of 0.59 V vs Ag/AgCl), shows a reduction of the operating voltage by 2 V, as well as remarkable enhancement of the luminance compared to the device on a pristine polymer anode. [ABSTRACT FROM AUTHOR]