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An in situ spectroelectrochemical study of the oxidation of the μ-oxosilicon phthalocyanine dimer [(SiPc)2O][OSiHx3]2 utilizing cyclic voltammetry, electron spin resonance spectroscopy, and visible–near infrared spectroscopy has been carried out. The results of this study show that oxidation of the dimer yields the paramagnetic radical dimer [(SiPc)2O][OSiHx3]2 + and then the diamagnetic dimer [(SiPc)2O][OSiHx3]22+. The study shows that the rings of [(SiPc)2O][OSiHx3]22+ are antiferromagnetically coupled.

The first intermediates of electrochemical reduction of nitro compounds in nonaqueous DMF are stable radical anions. In the series of mono-, di-, tri- and tetranitro calix[4]arenes each nitro group represents a reduction center, therefore the question about the spin state of intermediary anions arises. In this communication, the voltammetric and coulometric investigation of these compounds is performed together with the spectral measurements (ESR and UV-vis). The in-situ spectroelectrochemical approach proved that during reduction, in all polynitro radicalic intermediates the electrons remain unpaired and thus relatively stable mono-, di-, tri- and tetraradical mono-, di-, tri- and tetraanions, respectively, can be electrochemically generated in aprotic DMF from polynitrocalix[4]arenes. This finding confirms that the nitrophenyl units in polynitrocalix[4]arenes are completely independent and no mutual electronic communication takes place among them.

A detailed spectroelectrochemical and theoretical study of thienyl derivatives based on pyrene, namely 1-(2-thienyl)-pyrene (1), 1,6-bis(2-thienyl)-pyrene (2), 1,4-bis(2-thienyl)-pyrene (3), 1,3,6-tris(2-thienyl)-pyrene (4) and 1,3,6,8-tetra(2-thienyl)-pyrene (5), and their oxidation products with focus on the formation of their corresponding cationic states are presented. Regioregular polymeric systems were prepared by means of electrochemical polymerization from monomers 2–4. The redox behavior of the corresponding polymers was studied by cyclic voltammetry and in situ EPR/UV–vis–NIR spectroelectrochemistry with the aim of obtaining details on the type of charge carriers within the polymer film. Quantum chemical calculations of the optimal geometries and optical transitions for the neutral and charged forms were performed in order to reveal the influence of electrochemical oxidation on the molecular structure of the monomers and corresponding dimers and/or polymers.

Poly(2-methoxynaphthalene) (P2MN) belongs to the category of fused ring organic semiconductors that due to their planar structure have very interesting optical and electrical properties like a reduced band gap and easiness of undergoing both oxidation and reduction. Here, we present a spectroelectrochemical study by means of simultaneous recording of electron spin resonance–UV–vis–near infrared spectra (ESR–UV–vis–NIR) to probe the nature of the charge carriers in both p- and n-doped P2MN. As shown earlier P2MN is both p- and n-dopable, however, further information of the nature of both types of charge carriers is needed. In this work we demonstrate that the dominant charge carrier in p- and n-doped P2MN is positive and negative polarons, respectively. The material under study constitutes an example of an ambipolar organic conjugated polymer capable to conduct both holes and electrons. This is a unique property worthy to be further studied since only a few organic conducting polymers can reversibly be both p- and n-doped.

The three diphenylamino-endcapped thiophene compounds 1,4-bis-(2-diphenylamino-thiophen-5-yl)-benzene ( A ), 1,4-bis-[2-(phenothiazin-10-yl)-thiophen-5-yl]-benzene ( B ), and 1,4-bis-(5-diphenylamino-[2,2′]bithiophen-5′-yl)-benzene ( C ) with a central phenylene core were investigated by in situ ESR/UV–vis–NIR and in situ NMR spectroelectrochemistry and quantum chemical studies. The computed vertical ionization potentials are 4.85 eV for A , 5.39 eV for B and 4.80 eV for C while the adiabatic ionization potentials are slightly lower 4.45 eV (for A ), 4.96 eV (for B ) and 4.47 eV (for C ). The minimal difference between computed ionization potentials of A and C and the lower oxidation ability of B are in good agreement with the experimental electrochemical findings with the first half-wave anodic potentials 0.69 V (for A ), 0.81 V (for B ) and 0.67 V (for C ), all vs. decamethylferrocene (DmFc + /DmFc). For the radical monocations A + and C + the spin delocalisation on the central phenylene moiety was confirmed both experimentally and by theoretical calculations. For the radical cation B + , the presence of a phenothiazinyl moiety is responsible for the delocalization of unpaired electron in the lateral part of this molecule. The stability of the charged states was increased substantially by the incorporation of two further 2,5-thienylene moieties between the central moiety and the side groups in C . Detailed spectroelectrochemical studies of the cation radical, dication, trication and tetracation of C are in good agreement with the calculated electronic transitions and experimental values for all redox states. In situ NMR spectroelectrochemical studies at different temperatures indicate dimerisation reactions of charged 1,4-bis-(5-diphenylamino-[2,2′]bithiophen-5′-yl)-benzenes.

We demonstrate a single-molecule switch based on tunneling electron-driven rotation of a triangular Sc3N cluster within an icosahedral C80 fullerene cage among three pairs of enantiomorphic configurations. Scanning tunneling microscopy imaging of switching within single molecules and electronic structure theory identify the conformational isomers and their isomerization pathways. Bias-dependent action spectra and modeling identify the antisymmetric stretch vibration of Sc3N cluster to be the gateway for energy transfer from the tunneling electrons to the cluster rotation. Hierarchical switching of conductivity through the internal cluster motion among multiple stationary states while maintaining a constant shape, is advantageous for the integration of endohedral fullerene-based single-molecule memory and logic devices into parallel molecular computing architectures.

In situ electron spin resonance (ESR) spectroelectrochemical and thermoelectrochemical studies of the non-substituted α - and the alkyl substituted (in α , ω -positions) sexithiophenes as single molecules in solution are presented. Thus any influence of interactions of the molecules in the solid state is avoided. In nitrobenzene solution the life time of the cation radicals is sufficiently high to detect and characterize them by in situ ESR spectroscopy. Furthermore, the α -sexithiophene ( α -6T) was found to form insoluble films at the electrode surface by dimerization and polymerization while no film deposition at the electrode was detected for the end-capped α , ω -dihexylsexithiophene (DH-6T). In thermoelectrochemical experiments with continuous heating during anodic polarization, the polymer formation appears to be completely stopped. Obviously, the thermal stirring prevents the deposition of the generated polymer at the heated surface. The voltammetric waves corresponding to the radical cation or even the dication formation keep maintained in CV with permanent heating as well as with temperature-pulse voltammetry (TPV). With heating pulses being too short to initialize convection, the behavior was found different from that with permanent heating. Here, the polymerization at room temperature even with a somewhat increased rate causes a film formation at the electrode.

New experimental results on perfluoroalkylation of C{sub 60} and C{sub 70} with the use of R{sub f}I (R{sub f} = CF{sub 3}, C{sub 2}F{sub 5}, n-C{sub 3}F{sub 7}, n-C{sub 4}F{sub 9}, and n-C{sub 6}F{sub 13}), along with a critical overview of the existing synthetic methods, are presented. For the selected new fullerene (R{sub f}){sub n} compounds we report spectroscopic, electrochemical and structural data, including improved crystallographic data for the isomers of C{sub 70}(C{sub 2}F{sub 5}){sub 10} and C{sub 60}(C{sub 2}F{sub 5}){sub 10}, and the first X-ray structural data for the dodecasubstituted perfluoethylated C{sub 70} fullerene, C{sub 70}(C{sub 2}F{sub 5}){sub 12}, which possesses unprecedented addition pattern.

A series of novel oligoarylenes based on donor–acceptor system, containing triazine moiety as an electron-transporting central core, have been prepared by electrochemical polymerization. The redox behaviour of poly(2,4,6-tri[p-(2-(3,4-ethylenedioxythienyl))-phenyl]-1,3,5-triazine) was studied by cyclic voltammetry and triple in situ ESR/UV–vis–NIR spectroelectrochemistry to get more details on the type of charge carriers within the film. To obtain desired oligoarylenes, triazine-core monomers possessing various electrochromic side groups have been synthesized by the Stille cross-coupling methodology. The structures have been confirmed by 1H NMR, 13C NMR, and elemental analysis. Monomers show good chemical stability in common organic solvents such as chloroform, dichloromethane or toluene and also exhibit excellent thermal stability over wide range of temperatures. Furthermore, their photophysical properties have been established with the use of fluorescence spectroscopy. Electrochemical results accompanied with fluorescence spectroscopy suggest that these derivatives of triazine can be successfully used in the fabrication of organic light-emitting diodes (OLEDs).

The interaction of semiconducting single wall carbon nanotubes (SWCNT) and the conducting polymer poly(3,4-ethylendioxythiophene/polystyrenesulfonate) (PEDOT/PSS) was studied by Raman spectroscopy and in-situ Raman spectroelectrochemistry. The mixing of SWCNT with PEDOT/PSS caused a partial doping of SWCNT as indicated by the change of the relative intensity of the Raman features of SWCNT. The in situ Raman spectroelectrochemical measurements showed that semiconducting tubes could be doped even if they are embedded in PEDOT/PSS. However, in contrast to the neat SWCNT, the doping of SWCNT in composite is less efficient. For SWCNT in composite it is necessary to apply larger potential (by about 0.4–0.6 V) to achieve the same level of bleaching of Raman bands as in the case of neat SWCNT.

The interaction of double wall carbon nanotubes (DWCNTs) and the conducting polymer poly(3,4-ethylenedioxythiphene)/polystyrenesulfonate (PEDOT/PSS) was studied by in-situ Raman spectroelectrochemistry. The mixing of DWCNTs with PEDOT/PSS caused a partial doping of the outer tube of DWCNTs, which was indicated by the relative change of the Raman intensity of the DWCNTs features. On the other hand, the bands corresponding to inner tubes of DWCNTs and to the polymer were almost untouched by assembling both species into a composite. The in-situ Raman spectroelectrochemical experiments have shown that the changes in electronic structure of inner tubes of DWCNTs embedded in PEDOT/PSS matrix are dependent on the doping level. While at the low doping level of the composite, the Raman features of inner tubes of DWCNTs do not change significantly, at high doping level they reflect the changes caused by the applied electrochemical potential similar to those observed in the polymer-free DWCNTs.

Poly[2-(3-thienyl)ethyl acetate] (PTEtAc) was chemically synthesized and transformed to partially hydrolyzed PTEtAc (PTEtAcOH) and poly[2-(3-thienyl)ethanol] (PTEtOH). The influence of the acetoxy and hydroxyl terminal functionalities in the side groups on the electrochemical properties of these polyalkylthiophenes was studied by cyclic voltammetry and in situ FTIR spectroelectrochemistry. The cyclic voltammograms point to a chemically reversible behaviour of the p-doping process for PTEtAc and PTEtAcOH, while for PTEtOH the redox activity of the polymer film is lost during consecutive potential scans. The attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) was used to investigate the p-doping of the three different type of thiophene polymer films. In situ FTIR spectra taken at different electrode potentials in a cyclovoltammetric scan display the doping induced changes of the polymer pattern. Important differences in the behaviour of the polymers were observed and interpreted in terms of different film structures.

Superoxide radical (O2 −) was both electrochemically generated and detected at room temperature. In situ ESR spectroelectrochemistry with spin trapping was used for the radical detection. That is, the O2 − radical was obtained in a DMSO solution under cyclic voltammetry conditions as soon as the potential of the dioxygen electroreduction was reached. This radical reacted then with a 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) spin-trap reagent present in solution to form the DMPO– OOH adduct. The hyperfine coupling constants determined for the adduct were aN = 1.285 mT, a H β = 1.042 mT and a H γ = 0.142 mT in accord to those reported in literature.

The application of in situ ESR–UV/VIS/NIR spectroelectrochemistry to the highly purified C82:3 fullerene isomer with C2 symmetry made the detailed characterization of the radical structures formed by electrochemical generation possible. This first comprehensive spectroelectrochemical study of the stable radical anion and cation of an empty cage higher fullerene in acid-free organic electrolyte is a contribution to the general understanding of charged states at endohedral fullerenes. Keywords: Fullerenes, Fullerene ions, Ion radicals, ESR–UV/VIS/NIR spectroelectrochemistry

The influence of films of differently prepared single-walled carbon nanotubes (SWCNTs) and Ti6Al4V alloy on human osteoblasts was investigated. We focused on a metabolic activity of human osteoblasts as well as on their spreading and adherence ability on tested substrates. It was found that the metabolic activity of osteoblasts cultured on SWCNTs films was decreased of about 15% independently on the SWCNTs preparation technique. This result is comparable with that of osteoblasts cultured on Ti6Al4V alloy. It indicates that SWCNTs films are not toxic for human osteoblasts and could be used for biomedical applications.

The interaction of single wall carbon nanotubes (SWCNT) and the conducting polymer poly(3,4-ethylendioxythiophene/polystyrenesulfonate) (PEDOT/PSS) was studied by in situ Raman spectroelectrochemistry. The mixing of SWCNT with PEDOT/PSS caused a partial doping of SWCNT which was indicated by the change of relative intensity of the SWCNT Raman features. We have demonstrated for the first time that in situ Raman spectroelectrochemistry is a method of choice for precise and effective control of doping level of composites of conducting polymers and SWCNT. For electrochemical doping of SWCNT embedded in PEDOT/PSS the bleaching of RBM and TG modes of the SWCNT is delayed as compared to that in pure SWCNT. The delay is of about 0.2 V. This potential difference vanishes at higher potentials. The delayed response to doping is observed for both the SWCNT and the polymer matrix features. In the latter case the response is specific for individual polymer bands. Furthermore, during p-doping most of the polymer bands exhibit a subsequent monotonous bleaching. This contrasts with the behavior of the pristine polymer where the intensity changes are non-monotonous.

We have successfully resolved and visualized the structure of some chemically functionalized carbon nanotubes (CNTs) using high-resolution transmission electron microscopy (HRTEM) and electron energy loss spectroscopy (EELS). To represent the chemically modified CNT, we selected three systems. The first system is oxidized and surface thiolated MWCNT, the second system is Dy 3 N @ C 80 peapods prepared by depositing trimetal nitride fullerenes into SWCNT. The formed structure is the Dy 3 N @ C 80 @SWCNT. The third system is the conventional C 60 @SWCNT fullerene peapods, fluorinated by xenon difluoride (XeF2) up to 18% of F. We achieved detection of very low amount (0.6%) of sulfur and proved covalent bonding onto MWCNT surface. We present EELS imaging of the separated metal clusters inside endohedral metallofullerene peapod bundles and in the fluorinated C 60 peapods we show homogeneous fluorination across the whole surface.

This work reports on theoretical and spectroscopic study of recently prepared thermally and chemically stable ladder type molecules with extended π-conjugation consisting of fluoranthenopyracylene units. Density functional theory (DFT) and time-dependent DFT calculations were performed for the electronic ground and lowest excited states to obtain optimal geometries. Our calculations indicate both a planar structure of the central ladder part and a negligible influence of lateral phenylene rings. Geometrical changes upon the electronic excitations are indicated in the center of the molecular skeleton. Experimental absorption spectra of the investigated series measured in ortho dichlorobenzene consist of several bands, with well-distinguished vibronic structure. Effective conjugation length for excitation and fluorescence energy was estimated to be 10 and 9 repeating units, respectively.

A carbon allotrope containing solely linear sp-carbon chains (carbyne) [1] has not yet been demonstrated convincingly, but composite carbonaceous structures containing sp/sp carbon atoms attract increasing attention. Among various challenges, the possible occurrence of spcarbon chain in the interior of carbon nanotube [2] and its formation during heat treatment of double wall carbon nanotubes [3] have been discussed recently. In 1994, Heimann [4] suggested that sp-carbon chains may play a role as intermediates during shock-induced transformation of graphite into diamond. Indeed, diamond was found in the products of shock compression of carbynoid material grown by dehydrohalogenation of poly(vinylidene halide) [1,5]. An opposite effect, i.e., formation of carbyne via shock-compression of diamond was observed, too [6]. Interestingly, carbyne was found in a diamond mine in China [7], but geochemical aspects of the carbyne/diamond conversion are unknown. Sun et al. [8] prepared diamond by pyrolysis (600 C) of poly(phenylcarbyne), (PhC)n made by total dechlorination of a,a,a-trichlorotoluene [9]. This reaction is an explicit demonstration of terminological inconsistency of carbyne: the (PhC)n is solely sp -bonded polymer, in which the name ‘‘carbyne’’ is correctly used in terms of the IUPAC-codified name for a triply bonded carbon radical. Curiously, various sp-bonded carbon allotropes (also termed ‘‘carbyne’’ in historical sense) were found in the products of pyrolysis (1000–1600 C) of poly(phenylcarbyne), (PhC)n along with cubic and hexagonal diamond [9]. Kudryavtsev and Evsyukov [10] reported on diamond growth in dehydrohalogenated poly(vinylidene chloride) mixed with a catalytic amount (1 wt.%) of ultra-dispersed diamond. The growth took place at 360–370 C and atmospheric pressure, but the mechanism for catalytic diamond growth remained unknown. Here we report on a variant of this synthesis, in which the sp-chains were generated in situ from a mixture of poly(tetrafluoroethylene) PTFE with nanodiamond (nD) by the action of gaseous potassium. This study has been motivated by the fact that the ex-PTFE sp-chains are of exceptional quality [1,11] compared to other chemically synthesized analogues, and, secondly, the reaction can be carried out with a complete exclusion of air oxygen and humidity. As the sp-carbon chains are extremely reactive, the absence of any undesired reactant is a prerequisite for detailed studies of their reactions and structural modifications. Also the nanodiamond used by Kudryavtsev and Evsyukov [10] has been revealed to be composed of submicron-sized aggregates of primary particles [12]. Hence, it would be challenging to use the primary particles of nD with 4–5 nm in diameter [13] instead of their aggregates. The sample of primary nD particles used in this work was prepared by disintegrating of the commercial ultradispersed diamond, which in turn was isolated as grey powder by oxidizing detonation soot from TNT–RDX explosion with hot nitric acid, washing with water and drying at 120 C for 12 h [14]. Disintegration of aggregates was

ESR spectroelectrochemical measurements of 2-diphenylamino-substituted oligothiophenes 8m proved the existence of radical cations 8m+ upon oxidation. Their stability and dimerization depend significantly on the number m of thiophene units. The radical cations 81+ and 82+ are very reactive and dimerize spontaneously to yield either 2,5-bis(diphenylamino)-2,2′-bithiophene 102 or 2,5-bis(diphenylamino)-5,5′-bis(2-thienyl)-3,3′-bithiopene 112, respectively. In contrast, the radical cations 83+–85+ are highly stable and do not dimerize at all.

The first in situ electron paramagnetic resonance (EPR) spectroelectrochemical study of C 60 fullerene peapods (C 60 @SWCNT) as well as that of single-walled carbon nanotubes (SWCNTs) in different electrolyte solutions describes the formation of spin states by charge transfer reactions. Electrochemical reduction of peapods at high negative potentials causes the production of spins at the SWCNT site, while the intratubular fullerene is unchanged. Slightly anisotropic EPR signals were detected during electrochemical reduction of single-walled carbon nanotubes and fullerene peapods in the potential region from −1.75 to −2.15 V vs. decamethylferrocene/decamethylferrocinium couple. They are centered at g = 2.0038 and exhibit a hyperfine structure indicating the presence of functional groups containing N, O, H atoms in neighborhood. They differ from the EPR signals of chemically (potassium) doped SWCNT and C 60 @SWCNT. As the EPR signal is influenced by the electrolyte counter ions a reaction with electrolysis products of tetraalkylammonium cations is taken into consideration. No EPR lines of fullerene anions were found in electrochemically treated peapods, but these anions are detectable, if a free C 60 in solution is cathodically reduced on a SWCNT electrode.

The electronic properties of aminothiophene/gold interfaces have been investigated by photoemission spectroscopy in dependence of the amonithiophene conjugation length. The valence band onset as a measure for the charge injection barrier at these interfaces as well as the ionization potential depend on the length of the conjugated thiophene chain while the value of the interface dipole hardly varies. These results are discussed on the basis of recent theoretical approaches that aim to explain the interface dipoles.

Different types of redox doping of C60@SWCNT were monitored by Raman spectroscopy. Chemical doping was carried out by gaseous potassium, liquid potassium amalgam and gaseous fluorine diluted with argon. Electrochemical doping was investigated by in situ Raman spectroelectrochemistry in LiClO4 + acetonitrile solution and in 1-butyl-3-methylimidazolium tetrafluoroborate (ionic liquid). The peapods exhibit characteristic and complex feedback to chemical as well as to electrochemical doping. In contrast to chemical p-doping by F2, the Raman scattering of intratubular fullerene is selectively enhanced during electrochemical p-doping. Similar selective enhancement is traced at chemical n-doping with gaseous potassium. Doping by gaseous potassium causes deep reduction of intratubular C60 to C 60 6 - , which is not fully re-oxidizable upon contact to air. On the other hand, doping with liquid potassium amalgam causes reduction of intratubular C60 to C 60 4 - or C 60 5 - , and complete re-oxidation to neutral fullerene occurs spontaneously upon contact to air. In general, the doping chemistry of peapods is significantly dependent on the applied redox potential, charge-compensating counterions and on the actual doping technique used. A critical review of the current data is provided.

The preferential electrodeposition of Cu on a nanostructured C60 template was investigated and its mechanism presented. A template driven formation of copper nanocluster arrays was observed and spherical diffusion (UME) patterns were indicated. Variability in template local composition and internal resistance is expected to modulate individual nanoelement’s activity.

Double-walled carbon nanotubes were prepared by XeCl-laser irradiation of fullerene (C60 or C70) peapods. Raman spectroscopy evidences less defect structure of outer tubes, as compared to those in double-walled carbon nanotubes grown by thermal treatment of peapods. The diameter distribution also differs from that of the thermally prepared nanotubes. At the given laser fluence, the conversion of C70@SWCNT into double-walled carbon nanotubes was more efficient than the corresponding conversion of C60@SWCNT.

The design and characterisation of new electroactive polymers carrying functional (receptor) groups for ion recognition in the main or the side chain of the polymer are presented. For this purpose, thiophene polymer with an acetophenone group, 6-hydroxy-2-(2-(3-thienyl)-ethoxy)-acetophenone (3-AcpT), as well as salen-based polymers such as poly[(6,6′-bis-( o -methoxyphenyl)-2,2′-bipyridine)Ni(II)] and poly[( N , N ′-bis-(salicylidene)-ethylendiamine)Cu(II)] were studied. As spectroelectrochemical methods in situ ESR, ESR/UV–vis–NIR and FTIR spectroelectrochemistry were applied to follow both the paramagnetic and the diamagnetic species formed in redox reactions. Quantitative spectroelectrochemical analysis supports the preferable formation of ESR-silent (dicationic) chain segments upon oxidation in investigated polymer and copolymer structures, where the bipolarons and two interacting polarons in singlet state should be considered. The presented contribution besides the spectroelectrochemical characterisation discusses the potentiometric and voltammetric responses of salen-based polymers and copolymers in detection of Ni 2+ -ions.

The temperature dependence of the magnetic susceptibility of polyaniline at significant different doping levels has been investigated. The samples cover the conducting as well as the insulating region. The conductivity varies from 10−4 to 5 S cm−1. A temperature independent behaviour of the spin susceptibility is found in all cases. While the interpretation of the temperature dependence was formerly done by assuming metallic properties (Pauli paramagnetism) we give an alternative explanation of the results here based on the temperature dependence of a chemical equilibrium.

As model systems, differently fluorinated representatives from the family of phthalocyanines (CuPC, CuPCF4, and CuPCF16) with different ionization potentials were evaporated onto PEDOT:PSS (mixture of poly-3,4-ethylenedioxy-thiophene (PEDOT) and polystyrenesulfonate (PSS)) thin films, which are often applied as electrode material in (all-)organic semiconductor devices. The electronic interface properties were studied using both core and valence level photoemission spectroscopy. The alignment of the electronic levels of the phthalocyanines on PEDOT:PSS is compared to inert and reactive inorganic substrates. For reactive systems, the direction of the charge transfer depends clearly on both the ionization potential of the organic semiconductor and the work function of the substrate.

Using in situ ESR/UV–Vis–NIR cyclovoltammetry at different temperatures, model systems for blue copper proteins like [CuI(bite)]BF4 and [CuII(bite)](BF4)2 (bite=biphenyldiimino dithioether) were studied with respect to their redox behavior. Chemically reversible processes in the electrode reaction were observed by ESR and UV–Vis–NIR spectroscopy during the repetitive redox cycling of [CuI(bite)]BF4. The complex cyclovoltammetric feature of the compounds in acetonitrile can be explained by adsorption and a slow heterogeneous electron transfer with rate constant ks=2×10−4 cm s−1. Spectroelectrochemical studies of the redox products at 77 K confirmed the formation of a metastable pseudo-tetrahedral [CuII(bite)]2+ intermediate. This is direct experimental proof of processes in redox reactions of the [CuI(bite)]+ within a dual-pathway square reaction scheme indicating preferable electron transfer from the pseudo-tetrahedral [CuI(bite)]+ as the initial step. The DFT optimized geometries of quasi-tetrahedral and quasi-planar [CuI(bite)]+/2+ complexes are in reasonable agreement with experimental data.

The class of endohedral fullerenes is demonstrated in its large variety by the new type of nitride cluster fullerenes. These endohedral fullerenes were obtained as the most abundant fullerenes in the soot extract. This is reached by the concept of reactive gas atmosphere in arc burning fullerene production. The chemical reactions in the gas atmosphere during the production are described. Different nitride cluster fullerenes were produced with selectivity up to 90% by using reactive gas addition to the cooling gas of the arc burning process. Fullerenes prepared by this method are Sc3N@C80, Sc3−xErxN@C80 (x=1,2,3), Sc3N@C78, Y3N@C80, Ho3N@C80 and Tb3N@C80. By studying Vis/NIR spectra, it is demonstrated that nitride cluster fullerenes are generally large band-gap endohedrals. Therefore, the M3N@C80 structures are very stable and suitable for applications. This stability is caused by a charge transfer from the cluster to the carbon cage and the formation of a M3N–carbon cage bond as well as covalent metal–nitrogen bonds. Infrared spectroscopy of M3N@C80 was used to study the metal and cage size influence on the structure of the nitride cluster.

The work function of spin cast films of poly(3,4-ethylenedioxythiophene):poly(styrene-sulfonate) (PEDOT:PSS) was adjusted by electrochemical oxidation/reduction. The electrochemical equilibrium potential of these films was compared to the absolute value of the work function measured at dry films in ultra high vacuum by ultraviolet photoemission spectroscopy. A linear relationship between work function and equilibrium potential was found. It is shown that the redox state of the films is not changed by transferring the films into the dry state. The sodium content of the layers is strongly diminished after electrochemical treatment.

Single-wall carbon nanotubes, fullerene peapods (C60@SWCNT, C70@SWCNT) and double-wall carbon nanotubes can be charged electrochemically in various media, such as acetonitrile electrolyte solutions or 1-butyl-3-methylimidazolium tetrafluoroborate/hexafluorophosphate melts (ionic liquid). Electrochemistry of nanotubes and peapods is dominated by their capacitive double-layer charging. In-situ Vis-NIR spectra of nanotubes and peapods demonstrate reversible bleaching of the allowed optical transitions between van Hove singularities. The bleaching of optical transitions, induced by charge-transfer, is mirrored by quenching of resonance Raman spectra in the region of tube-related modes. The Raman modes of intratubular C60 in peapods exhibit considerable intensity increase upon anodic doping, but these modes are not enhanced at cathodic charging. The “anodic Raman enhancement” is specific for C60@SWCNT only. In the case of C70@SWCNT, symmetric quenching of the C70 Raman modes is detected at both cathodic and anodic potentials. Electrochemical charging in DWCNT points at specific response of the inner and outer tubes, the latter being more sensitive to doping.

Highly ordered C60 layers prepared on mica and HOPG (highly ordered pyrolytic graphite) substrates by physical vapour deposition were nanostructured by different electrochemical procedures using ionic liquid (1-butyl-3-methyl-imidazolium tetrafluoroborate) as electrolyte. The topology of the films is completely changed and a tenfold larger cluster size than in aqueous solutions was obtained. The most homogeneous films were obtained when lithium trifluoromethanesulfonate was added to the ionic liquid. FTIR spectroscopy was used to study the molecular structure of the nanostructured fullerene films.

Double wall carbon nanotubes (DWCNT) were studied by Raman spectroscopy and by in situ Raman spectroelectrochemistry. Two components of the G′-mode were assigned to the signals from inner and outer tubes. The dependence of the G′-mode intensity and frequency on the excitation laser energy was different for the inner and outer tubes. The changes in G′-mode caused by the applied electrochemical potential were discussed in detail. The red shifted component of the G′-mode exhibits delayed response to the electrochemical charging. Moreover, bleaching of the red shifted component was less symmetrical than that of the blue shifted component, if the applied electrode potential swept in anodic and cathodic directions. Hence, the Raman G′-mode has favorable properties for detailed characterization of DWCNT, both in the pristine state and upon electrochemical charging.

Redox reactions of C60, C120, C120O and C120OS in tetrabutylammonium tetrafluoroborate/o-dichlorobenzene solutions of high purity are studied by simultaneous measurement of UV–vis–NIR and ESR spectra during electrochemical reduction in dependence on the dimeric fullerene structure. It was found that C120 shows ESR behavior similar to C120O in the first electron transfer at 260 K characterized by the single ESR line of R2C60− fullerides. C120OS anions exhibit a sharp ESR line (linewidth 0.04 mT) with the characteristic feature of R4C60 anions indicating a strongly perturbed icosahedral symmetry of both C60 cages in the dimer. The stability of radical ions of the C60 dimers under study increases with the number of chemical bonds between both fullerene cages (C120

The population of valence-band electronic states of fullerene peapods (C60@SWCNT) was tuned electrochemically in acetonitrile solutions. Electrochemistry of peapods was dominated by their capacitive charging without distinct faradaic processes. In situ Vis–NIR spectra of peapods showed similar features as those of empty nanotubes. Electrochemical charging caused reversible bleaching of the transitions between Van Hove singularities. This bleaching was mirrored by quenching of resonance Raman spectra of the tube-related modes. The Ag(2) mode of C60 exhibits considerable intensity increase upon anodic doping of peapods, but this mode is not enhanced at cathodic charging.

Relatively stable Langmuir films of mono-, di-, and tetra- n -octyl adducts of C 60 were prepared at the water–air interface. The adducts were obtained by selective bulk electrosynthesis at controlled potential. For the films, surface pressure ( π ) and a surface potential change (Δ V ) were simultaneously measured as a function of surface area per molecule ( A ) during the film compression. The spreading properties of the adducts strongly depend on the number of n -octyl chains linked to the C 60 cage and nature of the spread solution. The determined zero-pressure limiting area per molecule ( A 0 ) is larger the more n -octyl chains are attached to the C 60 cage. Aggregated multilayer films are formed for the toluene and tetrahydrofuran spread solutions while liquid monolayer films for the chloroform solutions. Remarkably, relatively stable liquid monolayer films of pristine C 60 are obtained also from the chloroform solutions. For relatively concentrated chloroform solutions, plateaus are developed in the π – A adduct isotherms. Isotherms for both concentrated and diluted chloroform solutions show reversible compression and expansion with virtually no hysteresis. Comparison of the estimated and determined A 0 values indicates that all adduct molecules are horizontally oriented in the monolayer films. Unexpectedly, large mean dipole moment components normal to the water–air interface, determined from inflection points of the Δ V – A isotherms, are presumably due to preferential orientation of water molecules adjacent to the interface of the water subphase and the floating adduct film.

The kinetic and structural consequences of dimerisation as one of the main chemical follow-up reactions in electron transfer in organic molecules is very often not understood. As electrochemical methods result in an indirect description of dimerisation processes following electron transfer steps, spectroelectrochemical methods are needed for direct evidence of dimerisation. The triple in situ experimental technique for the simultaneous measurement of ESR and UV–vis–NIR spectra in electrochemical experiments at different temperatures, including a special TE102 optical ESR cavity and Bruker temperature control system, is presented in its application to redox reactions of dimeric structures and dimerisation reactions following an electron transfer. As redox systems, Wurster's reagent and thianthrene are used for reference work. The triple spectroelectrochemical method is successfully applied to extended organic π-conjugated systems like end-capped quarter-thiophene and dimeric fullerene C120 where the dimeric structures have been characterised in detail.

Raman scattering and infrared absorption is reported for various empty and filled fullerene isomers in the low-energy range below 600 cm−1 to clarify the influence of different carbon cage structures on the bonding strength between encapsulated metal ion and fullerene cage and to check the potential of vibrational spectroscopy for isomer identification. The spectra of three isomers of Tm@C82 and three isomers of Sc2@C84 were measured at room temperature. The results are compared to the response of the most abundant isomers of empty C84 as well as to data for C82 and C60. The vibrational structure of the higher empty fullerene cages C82 and C84 resembles a downshifted and split C60 spectrum. Moreover the spectra of the two C84 isomers exhibited only small differences due to the very similar molecular structure, i.e. identical hexagon indices and direct neighbourhood in the Stone–Wales conversion map. Larger differences of the low-energy cage modes were found for the Tm@C82 isomers and in particular for the Sc2@C84 isomers. This goes along with an increasing difference in hexagon indices and a larger distance on the Stone–Wales conversion map. Due to the charge transfer from the endohedral metal to the fullerene the low-energy cage modes are shifted in the same direction as the modes of C60 during the exohedral doping process with alkali metals. New lines induced by the endohedral scandium and thulium ions with almost complementary Raman and infrared intensities were found for Sc2@C84 below 200, around 250 and 260 cm−1 and for Tm@C82 at 116 to 118 cm−1 and at 42 cm−1. These vibrations were further identified as M–C2n stretching and M–C2n deformation modes. Only a minor influence of the cage isomerism on these modes was observed. This is consistent with a simple ionic picture for the interaction between carbon cage and encapsulated metal ion. It is the amount of metal to fullerene charge transfer and the distance of the oppositely charge centres which determine the carbon cage–metal ion bond strength.

Pyrex-filtered irradiation of C60 solutions in liquid diphenylmethane in the absence of oxygen is shown to result in Ph2CH⋅ radicals, which further react with the electron-deficient C60 to give Ph2CH–C60Hn (n=1, 3, 5). The fullerene ground state to 3 C 60 transition is suggested to be accompanied by the increase of the fullerene solvation affecting thus the acidity of methylene hydrogens in Ph2CH2 as well as the feasibility of their dissociation. Also, photolysis of C60 solutions in weakly acidic phenylacetylene is shown to lead to the addition of a varying number of phenylethinyl groups to the fullerene core.

The Raman spectra of metallic tubes in SWCNTs (Single wall carbon nanotubes) bundles during electrochemical doping have been investigated using three different electrolyte solutions: LiClO 4 /CH 3 CN, LiClO 4 /propylenecarbonate/poly(methyl methacrylate) and LiClO 4 /polyethyleneimine. Precise control of the electrochemical charging enabled us to follow the detailed development of the tangential displacement (TG) mode of SWCNT bundles in dependence on the electrode potential. The response of the TG mode to electrode potential was dependent on electrolyte used as a consequence of different doping efficiency. We demonstrate that the liquid electrolyte solution (LiClO 4 /CH 3 CN) has superior doping efficiency to those of both the tested polymer electrolytes.

The electrochemical redox process to charge and discharge polyaniline layers is studied by simultaneous Electron Spin Resonance (ESR) and UV–vis spectroscopic measurements. For this purpose, optically transparent electrodes were applied under potential-controlled conditions. The use of a calibrated manganese ESR standard ensures the calculation of the absolute numbers of free spins in the polymer layer during electrochemical doping. A general procedure is given to analyse the simultaneously recorded electrochemical and spectroscopic data. The procedure proposed following the time dependence of charge, ESR absorption and the absorbance demonstrates that the electrochemical charging/discharging mechanism of polyaniline can be described on the base of three oxidation states. In this way, the separated UV–vis spectra and the time/potential dependence of each redox state can be shown. Only little changes are observed in the shape of the separated spectra using the polaron/bipolaron model in comparison to the polaron/ σ -dimer model. A square ladder scheme of the redox mechanism is discussed, considering neutral, polaronic and bipolaronic states and the protonation equilibria. Furthermore, experimental evidence for the Faradaic nature of the “capacitive” current plateau is presented.

We present here the first studies on copolymer layers obtained from electrosynthesis of pyrrole and salen compounds. This work comes into the field of modified electrodes for sensoring applications. We investigated this electro-copolymerization because the coupling occurs by radical cation (RC) coupling for both compounds. The electrochemical behavior was studied by cyclic voltammetry, spectroelectrochemistry and in situ electron spin resonance (ESR); quantitative characterization was performed with electron dispersive spectroscopy and mass spectrometry (Maldi-Tof). In the case of the copolymer prepared with little pyrrole (versus salen) in the starting solution, the ESR data gave no typical PPy signal although cyclic voltammograms (CVs) were completely different from those of poly(salen). The composition of the layers is estimated with good approximation and this is evidently an interesting material for sensoring applications such as gas (vapor) or heavy metal sensors.

Stable regular honeycomb structures of various polypyrroles having a stick width of 50 μm and a structure height of 110 μm were formed by the electropolymerization of pyrrole or substituted pyrrole in aqueous solutions at high current densities. The advantages of these microstructures in sensorics and spectroelectrochemistry are shown for specific applications. The high electrical conductivity and the stability of the polymer were attained using aromatic sulfonate derivatives as electrolytes. Regular honeycomb structured polymer electrodes with channels of 50 μm were prepared and used for electrochemical and spectroelectrochemical studies. The cation-exchange properties of such structures were tested by Al3+ ions. The preparation of PPy–LIGA structures with specific groups was demonstrated by copolymerization of pyrrole with pyrrole-2-carboxylic acid. The high sensitivity and specificity of ESR signal of PPy–LIGA structures to the oxygen was observed.

The interaction of divalent metal ions with styrene–maleic acid-copolymer (SMA copolymer) has been studied. Polarography, voltammetry on a hanging mercury electrode and UV-VIS spectroscopy were applied to evaluate formation constants for complexation of Cu(II), Zn(II) and Ni(II) ions with the polyelectrolyte SMA copolymer as well as monomeric dicarboxylic acids in aqueous solution. Considering adsorption of the polymer on the Hg electrode the studies show that SMA acts as strong ligand for Cu(II) ions while complexation with Zn(II) is less strong. Voltammetric behavior of Ni(II) in polymer solutions was found to be rather complex. Formation constants of Cu(II) and Zn(II) polymer complexes are considerably greater compared to the corresponding monomeric metal complexes. The results reported point to a strong influence of metal dissolution on the mechanism of deposition of MA copolymers on copper, zinc and nickel electrodes.

Eu@C74, the first europium metallofullerene isolated so far is studied by VIS/NIR, infrared, Raman and ESR spectroscopy to clarify its redox state. The electrochemical behaviour was investigated by cyclic voltammetry. Based on the results of all these characterisation methods, we propose an electronic state Eu2+@C742−. No isomerism was to be detected for this endohedral fullerene.

The study on the very first stages of electrochemical polymerization of aniline and p-aminodiphenylamine (p-ADPA) on electrodes by in situ FT-IR/ATR and UV-Vis transmission techniques is presented. The in situ FT-IR/ATR measurements indicate the highest polymer growth rate during the reversed cathodic potential scan in potentiodynamic electropolymerization. In this scan direction the p-ADPA radical is formed in a less anodic potential region by symproportionation of the soluble oxidized dimer N-phenyl-quinonediimine with p-ADPA formed by re-reduction. The resulting radical formed by symproportionation causes the polymer growth. The radical cations form the tetrameric Willstatter blue and red imine by dimerization and further oxidation. Therefore, the main step in polymer deposition is the radical reaction of p-ADPA. By further reactions of the first oligomers, insoluble higher oligomers are formed and deposited on the electrode. The preferred occurrence of these reactions is the reason for the more intense polymer growth by cycling of the potential in comparison to potentiostatic methods. Comparative studies of the p-ADPA polymerization were done under the same conditions. The comparison of FT-IR vibration modes of PANI and polymerized p-ADPA shows significant structural differences of both polymers. By FT-IR and UV-Vis spectroscopy it is shown that the main structure of polymerized p-ADPA is the aniline tetramer Willstatter blue/red imine.

In situ FTIR spectroscopy has been used to study the structures of the very first polymerization products of aniline and the structural changes of the initial layers during redox processes. In the present study, the techniques of Attenuated Total Reflection (ATR) and IR Reflection Absorption Spectroscopy (IRRAS) have been coupled with electrochemical measurements. The low penetration depth of the IR radiation in the ATR spectroscopy gives rise of structural information of the polymer film at the electrode. The IRRAS technique was used to study the changes of the interface polymer/electrolyte. With ATR spectroscopy spectra of the initial states of potentiodynamic electropolymerization in aqueous solution are presented. The highest polymer growth rate was found during the cathodic scan when radicals are formed by symproportionation of oxidized and reduced dimers. With IRRAS technique structural changes of PANI were observed during oxidation. Pure benzoid ring vibrations decrease and alternating benzoid and quinoid sequences were detected.

The electrochemical reduction of 2,5-diphenyl-1,3,4-oxadiazole has been studied by both cyclic voltammetry and spectroelectrochemistry. The in situ spectroscopic techniques were applied to obtain structural information on the products of the follow-up reactions. Time-resolved UV-vis spectroscopy, with spectra measured on a time scale of 20ms by a diode array spectrometer, was used in cyclic voltammetry to obtain up to 60 single spectra in the forward and backward scans. The radical anion of 2,5-diphenyl-1,3,4-oxadiazole, which is formed in the electron transfer reaction at the electrode, was studied by ESR spectroscopy. Furthermore, paramagnetic products of the follow-up reactions were detected. A reaction mechanism is formulated that includes an irreversible protonation reaction and, in parallel, a reversible ion-pairing reaction with the supporting electrolyte cation for the electrochemically generated radical anion and an irreversible follow-up reaction for the dianion of 2,5-diphenyl-l,3,4-oxadiazole.

Simultaneous in situ measurements by both ESR and UV-vis spectroscopy have been carried out at the same electrode for the first time during a single electrochemical experiment in order to spectroscopically characterize the electrochemical reaction products. The experimental technique, including a special TE102 optical ESR cavity and an electrochemical cell for both ESR and UV-vis spectroscopy in transmission, is described. It is shown that the UV-vis absorbance measured in situ, as well as the ESR intensity characteristics of the electrochemical system under study, can be understood in terms of the faradaic current. The reliability of this system is proved by measuring the organic redox couple of methyl-substituted p-phenylenediamine and by comparing calculated and experimental curves.