% Encoding: UTF-8
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@article{faucris.120239064,
abstract = {A molecular donor-acceptor dyad comprising a hexarhenium cluster core, [Re(m-Se)], and a fullerene moiety which are covalently linked through a pyridine ligand was synthesized and fully characterized. The electrochemical and photophysical properties are reported. The detailed study includes cyclic voltammetry, steady-state absorption and fluorescence spectroscopy, radiation chemistry and transient absorption spectroscopy. A light-induced electron transfer between the inorganic cluster moiety and the fullerene can be excluded. However, a light-induced energy transfer from the rhenium cluster to the fullerene is proposed © Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.},
author = {Kahnt, Axel and Heiniger, Leo-Philipp and Liu, Shi-Xia and Tu, Xiaoyan and Zheng, Zhiping and Hauser, Andreas and Decurtins, Silvio and Guldi, Dirk Michael},
doi = {10.1002/cphc.200900728},
faupublication = {yes},
journal = {ChemPhysChem},
pages = {651-658},
peerreviewed = {Yes},
title = {{An} electrochemical and photophysical study of a covalently linked inorganic-organic dyad},
volume = {11},
year = {2010}
}
@article{faucris.123911964,
abstract = {Luminescent carbon nanodots exhibit enormous potential to be used as functional building blocks in energy conversion devices. Their intrinsic heterogeneity, however, hinders a thorough characterization and subsequently their applicability. In this work, the spectroscopic and electrochemical properties of prototype carbon nanodots were thoroughly studied in solution. Spectro-electrochemical experiments revealed information on the spectral features of several oxidized and reduced species of our carbon nanodots. Therefore, these experiments were complemented with pulse radiolysis where the spectral signature of the one-electron oxidized and reduced forms were identified. Both, electrochemically and radiolytically reduced and oxidized products show high reactivity in solution which correlates with an open-shell character, detected by paramagnetic resonance spectroscopy. The herein presented studies help to understand the complex nature of carbon nanodots and serve to overcome difficulties in device fabrication.},
author = {Strauß, Volker and Kahnt, Axel and Zolnhofer, Eva and Meyer, Karsten and Maid, Harald and Placht, Christian and Bauer, Walter and Nacken, Thomas and Peukert, Wolfgang and Etschel, Sebastian and Halik, Marcus and Guldi, Dirk Michael},
doi = {10.1002/adfm.201602325},
faupublication = {yes},
journal = {Advanced Functional Materials},
pages = {7975-7985},
peerreviewed = {unknown},
title = {{Assigning} {Electronic} {States} in {Carbon} {Nanodots}},
url = {http://onlinelibrary.wiley.com/doi/10.1002/adfm.201602325/full},
volume = {26},
year = {2016}
}
@article{faucris.112369004,
abstract = {Different nanocarbons, that is, single-wall carbon nanotubes, graphene, single-wall carbon nanohorns (SWCNHs), and their respective oxidized analogs have been used to fabricate novel doped TiO2 electrodes for DSSCs. Our results indicate that all of the nanocarbons significantly enhance the device characteristics when compared to standard TiO2 electrodes. Overall, our most outstanding finding is that SWCNH derivatives are also a plausible material for developing highly-efficient DSSCs.},
author = {Costa Riquelme, Rubén Dario and Feihl, Sebastian and Kahnt, Axel and Gambhir, Sanjeev and Officer, David L. and Wallace, Gordon G. and Lucio, Mara Isabel and Herrero, Mara Antonia and Vzquez, Ester and Syrgiannis, Zois and Prato, Maurizio and Guldi, Dirk Michael},
doi = {10.1002/adma.201301527},
faupublication = {yes},
journal = {Advanced Materials},
peerreviewed = {Yes},
title = {{Carbon} {Nanohorns} as {Integrative} {Materials} for {Efficient} {Dye}-{Sensitized} {Solar} {Cells}},
year = {2013}
}
@article{faucris.107567724,
abstract = {A photo- and redoxactive system ZnPc-oPPV-C 2, in which the photoexcited state electron donor - zinc phthalocyanine - and the ground state electron acceptor - C - are connected by a oligo(p- phenylenevinylene) (oPPV) spacer, has been synthesized in a multi-step synthesis by means of two consecutive Wadsworth-Horner-Emmons and a dipolar 1,3-cycloaddition reactions as key steps. The simpler system ZnPc-C 1 has also been prepared as a reference model for photophysical studies. In this regards, the photophysical investigations by means of fluorescence, flash photolysis, and transient-absorption spectroscopy have manifested a clear dependence between charge transfer kinetics and spatial arrangement. In both systems, intramolecular charge separation evolves from the photoexcited ZnPc and yields the ZnPc /C radical ion pairs. Interestingly, the ZnPc /C radical ion pair lifetimes and quantum yields are strongly impacted by the solvent polarity and the distance. To this end, maximum radical ion pair lifetimes of 2900 and 5530 ps were found in anisol for 1 and 2, respectively. © 2011 Elsevier Inc. All rights reserved.},
author = {Cid, Juan-Jose and Kahnt, Axel and Vazquez, Purificacion and Guldi, Dirk Michael and Torres, Tomas},
doi = {10.1016/j.jinorgbio.2011.11.011},
faupublication = {yes},
journal = {Journal of Inorganic Biochemistry},
pages = {216-224},
peerreviewed = {Yes},
title = {{Charge} separation in a covalently-linked phthalocyanine-oligo(p- phenylenevinylene)-{C60} system. {Influence} of the solvent polarity},
volume = {108},
year = {2012}
}
@article{faucris.258182481,
abstract = {Substituted 2,6-dicyanoanilines are versatile electron donor-acceptor compounds, which have recently received considerable attention, since they exhibit strong fluorescence and may have utility in the synthesis of fluorescent materials, non-natural photosynthetic systems, and materials with nonlinear optical properties. The majority of known synthetic procedures are, however, "stop-and-go"reaction processes involving time-consuming and waste-producing isolation and purification of product intermediates. Here, we present the synthesis of substituted 2,6-dicyanoanilines via atom-economical and eco-friendly one-pot processes, involving metal-free domino reactions, and their subsequent photochemical and photophysical measurements and theoretical calculations. These studies exhibit the existence of an easily tunable radical ion pair-based charge-transfer (CT) emission in the synthesized 2,6-dicyanoaniline-based electron donor-acceptor systems. The charge-transfer processes were explored by photochemical and radiation chemical measurements, in particular, based on femtosecond laser photolysis transient absorption spectroscopy and time-resolved emission spectroscopy, accompanied by pulse radiolysis and complemented by quantum chemical investigations employing time-dependent density-functional theory. This chromophore class exhibits a broad-wavelength-range fine-tunable charge recombination emission with high photoluminescence quantum yields up to 0.98. Together with its rather simple and cost-effective synthesis (using easily available starting materials) and customizable properties, it renders this class of compounds feasible candidates as potential dyes for future optoelectronic devices like organic light-emitting diodes (OLEDs). },
author = {Plass, Fabian and Bönisch, Simon and Held, Felix and Ullrich, Tobias and Fischer, Florian and Guryev, Anton and Görling, Andreas and Kahnt, Axel and Tsogoeva, Svetlana},
doi = {10.1021/acs.joc.0c02944},
faupublication = {yes},
journal = {Journal of Organic Chemistry},
note = {CRIS-Team Scopus Importer:2021-05-14},
peerreviewed = {Yes},
title = {{Controlling} and {Fine}-{Tuning} {Charge}-{Transfer} {Emission} in 2,6-{Dicyanoaniline} {Multichromophores} {Prepared} through {Domino} {Reactions}: {Entry} to a {Potentially} {New} {Class} of {OLEDs}},
year = {2021}
}
@article{faucris.259851673,
abstract = {Herein, the synthesis of three covalently linked donor-acceptor zinc porphyrin-fullerene (ZnP-C-60) dyads (C(60)trZnPCOOH, C(60)trZnPtrCOOH and C60ZnPCOOH) is described, and their application as sensitizers in NiO-based dye-sensitized solar cells (DSCs) is discussed. To the best of our knowledge, this is the first example where covalently linked ZnP-C-60 dyads have been used as chromophores in NiO-based DSCs. In an effort to examine whether the distance of the chromophore from the electron acceptor entity and/or the NiO surface affects the performance of the cells, a triazole ring was introduced as a spacer between ZnP and the two peripheral units C-60 and -COOH. The triazole ring was inserted between ZnP and C-60 in dyad C(60)trZnPCOOH, whereas both the anchoring group and C-60 were connected to ZnP through triazole spacers in C(60)trZnPtrCOOH, and dyad C60ZnPCOOH did not contain any triazole linker. Photophysical investigation performed by ultrafast transient absorption spectroscopy in solution and on the NiO surface demonstrated that all the porphyrin-fullerene dyads exhibited long-lived charge-separated states due to electron shifts from the reduced porphyrin core to C-60. The transient experiments performed in solution showed that the presence of triazole ring influenced the photophysical properties of the dyads C(60)trZnPCOOH and C(60)trZnPtrCOOH and in particular, increased the lifetime of the charge-separated states compared to that of the C60ZnPCOOH dyad. On the other hand, the corresponding studies on the NiO surface proved that the triazole spacer has a rather moderate impact on the charge separation (NiO-ZnP center dot+-C-60(center dot-)) and charge recombination (NiO-(3)*ZnP-C-60) rate constants. All three dyads exhibited enhanced performance in terms of photovoltaic measurements with more than threefold increase compared to the reference compound PhtrZnPCOOH in which the C-60 acceptor is absent. Two different electrolytes were examined (I-3(-)/I- and Co-III/II) and in most cases, the presence of the triazole ring enhanced their photovoltaic performance. The best performing dyad in I-3(-)/I- was C(60)trZnPCOOH (PCE = 0.076%); in Co-III/II, the best performing dyad was C(60)trZnPtrCOOH (PCE = 0.074%).},
author = {Nikolaou, Vasilis and Plass, Fabian and Planchat, Aurelien and Charisiadis, Asterios and Charalambidis, Georgios and Angaridis, Panagiotis A. and Kahnt, Axel and Odobel, Fabrice and Coutsolelos, Athanassios G.},
doi = {10.1039/c8cp04060e},
faupublication = {yes},
journal = {Physical Chemistry Chemical Physics},
note = {Created from Fastlane, WoS look-up},
pages = {24477-24489},
peerreviewed = {Yes},
title = {{Effect} of the triazole ring in zinc porphyrin-fullerene dyads on the charge transfer processes in {NiO}-based devices},
volume = {20},
year = {2018}
}
@article{faucris.213382297,
abstract = {We use free-standing TiO2 nanotube membranes that are transferred onto FTO slides in front-side illuminated dye-sensitized solar cells (DSSCs). We investigate the key parameters for solar cell arrangement of self-ordered anodic TiO2 nanotube layers on the FTO substrate, namely the influence of the annealing procedure on the DSSC light conversion efficiency. The results show that using an optimal temperature annealing profile can significantly enhance the DSSC efficiency (in our case \textgreekh = 9.8%), as it leads to a markedly lower density of trapping states in the tube oxide, and thus to strongly improved electron transport properties.},
author = {Mohammadpour, F. and Moradi, M. and Lee, Kiyoung and Cha, Gi and So, Seulgi and Kahnt, Axel and Guldi, Dirk Michael and Altomare, Marco and Schmuki, Patrik},
doi = {10.1039/c4cc08266d},
faupublication = {yes},
journal = {Chemical Communications},
note = {EAM Import::2019-03-14},
pages = {1631-1634},
peerreviewed = {Yes},
title = {{Enhanced} performance of dye-sensitized solar cells based on {TiO2} nanotube membranes using an optimized annealing profile},
volume = {51},
year = {2015}
}
@article{faucris.120424084,
abstract = {Charge carriers, that is, holes as well as trapped and "free" electrons were investigated by means of time resolved spectroscopy in anodic TiO nanotubes that were heat treated at different temperatures. The lifetimes of the charge carrier were compared with those generated in reference layers of Solaronix Ti-Nanoxide D and Degussa P25 nanoparticles. Remarkably long lived "free" electrons were only noted in the TiO nanotubes. These findings have significance in view of any photoelectrochemical applications of TiO nanotubes. © 2013 2013 Author(s).},
author = {Kahnt, Axel and Oelsner, Christian and Werner, Fabian and Guldi, Dirk Michael and Albu, Sergiu and Kirchgeorg, Robin and Lee, Kiyoung and Schmuki, Patrik},
doi = {10.1063/1.4810762},
faupublication = {yes},
journal = {Applied Physics Letters},
peerreviewed = {Yes},
title = {{Excited} state properties of anodic {TiO2} nanotubes},
volume = {102},
year = {2013}
}
@article{faucris.205204088,
abstract = {Most of the known approved drugs comprise functionalized heterocyclic compounds as subunits. Among them, non-fluorescent quinazolines with four different substitution patterns are found in a variety of clinically used pharmaceuticals, while 4,5,7,8-substituted quinazolines and those displaying their own specific fluorescence, favourable for cellular uptake visualization, have not been described so far. Here we report the development of a one-pot synthetic strategy to access these 4,5,7,8-substituted quinazolines, which are fluorescent and feature strong antiviral properties (EC50down to 0.6±0.1 μM) against human cytomegalovirus (HCMV). Merging multistep domino processes in one-pot under fully metal-free conditions leads to sustainable, maximum efficient and high-yielding organic synthesis. Furthermore, generation of artesunic acid-quinazoline hybrids and their application against HCMV (EC50down to 0.1±0.0 μM) is demonstrated. Fluorescence of new antiviral hybrids and quinazolines has potential applications in molecular imaging in drug development and mechanistic studies, avoiding requirement of linkage to external fluorescent markers.},
author = {Held, Felix and Guryev, Anton and Fröhlich, Tony and Hampel, Frank and Kahnt, Axel and Hutterer, Corina and Steingruber, Mirjam and Bahsi, Hanife and Von Bojnicic-Kninski, Clemens and Mattes, Daniela S. and Foertsch, Tobias C. and Nesterov-Mueller, Alexander and Marschall, Manfred and Tsogoeva, Svetlana},
doi = {10.1038/ncomms15071},
faupublication = {yes},
journal = {Nature Communications},
note = {EVALuna2:33762},
peerreviewed = {Yes},
title = {{Facile} access to potent antiviral quinazoline heterocycles with fluorescence properties via merging metal-free domino reactions},
volume = {8},
year = {2017}
}
@article{faucris.263540901,
abstract = {Hexaarylbenzene (HAB) derivatives are versatile aromatic systems playing a significant role as chromophores, liquid crystalline materials, molecular receptors, molecular-scale devices, organic light-emitting diodes and candidates for organic electronics. Statistical synthesis of simple symmetrical HABs is known via cyclotrimerization or Diels-Alder reactions. By contrast, the synthesis of more complex, asymmetrical systems, and without involvement of statistical steps, remains an unsolved problem. Here we present a generally applicable synthetic strategy to access asymmetrical HAB via an atom-economical and high-yielding metal-free four-step domino reaction using nitrostyrenes and alpha,alpha-dicyanoolefins as easily available starting materials. Resulting domino product-functionalized triarylbenzene (TAB)-can be used as a key starting compound to furnish asymmetrically substituted hexaarylbenzenes in high overall yield and without involvement of statistical steps. This straightforward domino process represents a distinct approach to create diverse and still unexplored HAB scaffolds, containing six different aromatic rings around central benzene core.},
author = {Grau, Benedikt and Dill, Maximilian and Hampel, Frank and Kahnt, Axel and Jux, Norbert and Tsogoeva, Svetlana},
doi = {10.1002/anie.202104437},
faupublication = {yes},
journal = {Angewandte Chemie International Edition},
note = {CRIS-Team WoS Importer:2021-09-03},
peerreviewed = {Yes},
title = {{Four}-{Step} {Domino} {Reaction} {Enables} {Fully} {Controlled} {Non}-{Statistical} {Synthesis} of {Hexaarylbenzene} with {Six} {Different} {Aryl} {Groups}**},
year = {2021}
}
@article{faucris.290208846,
author = {Bottari, Giovanni and Trukhina, Olga and Kahnt, Axel and Frunzi, Michael and Murata, Yasujiro and Rodríguez-Fortea, Antonio and Poblet, Josep M. and Guldi, Dirk Michael and Torres, Tomás},
doi = {10.1002/anie.201683761},
faupublication = {yes},
journal = {Angewandte Chemie International Edition},
keywords = {atropisomerism; cycloaddition; fullerenes; phthalocyanines; supramolecular chemistry},
note = {CRIS-Team Scopus Importer:2023-03-07},
peerreviewed = {Yes},
title = {{Frontispiece}: {Regio}-, {Stereo}-, and {Atropselective} {Synthesis} of {C60Fullerene} {Bisadducts} by {Supramolecular}-{Directed} {Functionalization}},
volume = {55},
year = {2016}
}
@article{faucris.213332362,
abstract = {A new insight into photoinduced charge transfer processes across carbon nanotube@TiO2 interfaces has been gained based on experimental details from transient absorption spectroscopy. We show that photoinduced, interfacial hole transfer to carboxylic acid-functionalized multiwalled carbon nanotubes (oxMWCNTs) from TiO2 results in hole-doped oxMWCNTs and reduced TiO2. The latter is inferred from femto- and nanosecond transient absorption spectroscopy performed with oxMWCNT@TiO2 dispersions and complemented with investigations using methyl viologen and N,N,N',N'-tetramethyl-p-phenylenediamine as an electron scavenger and a hole scavenger, respectively. The results of ultraviolet photoemission spectroscopy (UPS) of the compounds corroborate the findings, highlighting the strong coupling between oxMWCNTs and TiO2 in these hybrids.},
author = {Saha, Avishek and Moya, Alicia and Kahnt, Axel and Iglesias, Daniel and Marchesan, Silvia and Wannemacher, Reinhold and Prato, Maurizio and Vilatela, Juan J. and Guldi, Dirk Michael},
doi = {10.1039/c7nr00759k},
faupublication = {yes},
journal = {Nanoscale},
note = {EAM Import::2019-03-13},
pages = {7911-7921},
peerreviewed = {Yes},
title = {{Interfacial} charge transfer in functionalized multi-walled carbon nanotube@{TiO2} nanofibres},
volume = {9},
year = {2017}
}
@article{faucris.259851924,
abstract = {We report on the synthesis, characterization and photophysical properties of a donor-bridge-acceptor supramolecular hybrid system, consisting of a tetrapyridyl fullerene derivative (C-60-tpyr) as electron acceptor, with the four pyridyl groups as part of oligophenyleneethynylene/phenylenevinylene bridges, and zinc porphyrin dimers (ZnP)(2) as electron donor species. Based on the metal-to-ligand coordination between the zinc metal centers of (ZnP)(2) and the four pyridyl entities of C-60-tpyr, a strong binding constant (5 x 10(5) M-1) for the formation of C-60-tpyr[(ZnP)(2)](2) was evidenced. Insights into the electronic interactions between the photoactive (ZnP)(2) units and C-60-tpyr emanated from complementary physicochemical assays, which were further supported by theoretical calculations. Notably, the absorption and emission titration assays revealed strong interactions between the electron donor and acceptor species within C-60-tpyr[(ZnP)(2)](2), both in the ground and excited state. Moreover, femtosecond and nanosecond laser photolysis transient absorption measurements were performed and provided solid evidence for intramolecular electron transfer processes derived from the singlet excited state of (ZnP)(2) to C-60-tpyr. Comparison with systems in which either four monomeric zinc porphyrins (ZnP) were complexed with C-60-tpyr or a (ZnP)(2) was coordinated with a dipyridylfullerene revealed the beneficial role of C-60-tpyr in increasing the lifetime of charge-separation.},
author = {Stangel, Christina and Plass, Fabian and Charisiadis, Asterios and Giannoudis, Emmanouil and Chararalambidis, Georgios and Karikis, Kostas and Rotas, Georgios and Zervaki, Galateia E. and Lathiotakis, Nektarios N. and Tagmatarchis, Nikos and Kahnt, Axel and Coutsolelos, Athanassios G.},
doi = {10.1039/c8cp03172j},
faupublication = {yes},
journal = {Physical Chemistry Chemical Physics},
note = {Created from Fastlane, WoS look-up},
peerreviewed = {Yes},
title = {{Interfacing} tetrapyridyl-{C}-60 with porphyrin dimers via -conjugated bridges: artificial photosynthetic systems with ultrafast charge separation},
volume = {20},
year = {2018}
}
@article{faucris.121906444,
abstract = {Ball milling TiO2 anatase together with TiH2 can create an effective photocatalyst. The process changes the lattice and electronic structure of anatase. Lattice deformation created by mechanical impact combined with hydride incorporation yield electronic gap-states close to the conduction band of anatase. These provide longer lifetimes of photogenerated charge carriers and lead to an intrinsic cocatalytic activation of anatase for H2 evolution.},
author = {Zhou, Xuemei and Liu, Ning and Schmidt, Jochen and Kahnt, Axel and Osvet, Andres and Romeis, Stefan and Zolnhofer, Eva and Marthala, Venkata and Guldi, Dirk Michael and Peukert, Wolfgang and Hartmann, Martin and Meyer, Karsten and Schmuki, Patrik},
doi = {10.1002/adma.201604747},
faupublication = {yes},
journal = {Advanced Materials},
keywords = {Anatase; Ball milling; Hydrogen evolution; Photocatalysis; Titanium hydride},
peerreviewed = {unknown},
title = {{Noble}-{Metal}-{Free} {Photocatalytic} {Hydrogen} {Evolution} {Activity}: {The} {Impact} of {Ball} {Milling} {Anatase} {Nanopowders} with {TiH2}},
year = {2016}
}
@article{faucris.120259524,
abstract = {We report on the synthesis of hybrid molecules consisting of a porphyrin or corrole chromophore axially coordinated to a [Co(dmgH) (Cl)] (dmg = dimethylglyoxime) unit via a pyridine group as potential hydrogen forming entities in HO/THF medium. Photophysical, electrochemical, and pulse radiolysis studies on the hybrids and/or their separate components show that selective excitation of the porphyrin or corrole chromophore in its first singlet excited state leads to fast charge separation due to chromophore to cobalt electron transfer. However, this charge separation is followed by even faster charge recombination thereby preventing the accumulation of a reduced cobalt species which would lead to hydrogen production. It is important, nevertheless, that addition of a sacrificial electron donor slows the charge recombination down. In light of the latter it comes as hardly surprising that the photocatalysis experiments in the presence of a sacrificial electron donor (i.e., triethylamine) show modest rates of hydrogen production. © 2012 American Chemical Society.},
author = {Peuntinger, Katrin and Lazarides, Theodore and Dafnomili, Dimitra and Charalambidis, Georgios and Landrou, Georgios and Kahnt, Axel and Sabatini, Randy Pat and Mccamant, David W. and Gryko, Daniel T. and Coutsolelos, Athanassios G. and Guldi, Dirk Michael},
doi = {10.1021/jp311766s},
faupublication = {yes},
journal = {Journal of Physical Chemistry C},
pages = {1647-1655},
peerreviewed = {Yes},
title = {{Photoinduced} charge transfer in porphyrin-cobaloxime and corrole-cobaloxime hybrids},
volume = {117},
year = {2013}
}
@article{faucris.120233784,
abstract = {The effect of the protonation on the photophysical properties (i.e., ground state and excited state properties) of Zn(II)phthalocyanine (Zn(II)Pc) 2 and covalently-linked, electron donor-acceptor Zn(II)Pc-C 1 have been investigated. On one hand, important changes in the absorption features of these two systems have been seen upon addition of trifluoroacetic acid due to protonation of some meso nitrogens of the Pc moiety. On the other hand, significant changes in the lifetime of the singlet excited states - in the case of 1 and 2 - and of the charge-separated state - in the case of 1 - were also observed. We reckon that this study, unprecedented in term of the study of the time-resolved excited state features of a protonated Pc-C conjugate, will contribute in terms of shedding light toward a better understanding of photoinduced processes in Pc-based systems. © 2013 The Electrochemical Society.},
author = {Bottari, Giovanni and Kahnt, Axel and Guldi, Dirk Michael and Torres, Tomas},
doi = {10.1149/2.016310jss},
faupublication = {yes},
journal = {ECS Journal of Solid State Science and Technology},
peerreviewed = {unknown},
title = {{Protonation}-induced changes in the photophysical properties of a phthalocyanine and a covalently-linked, phthalocyanine-{C60} fullerene dyad},
volume = {2},
year = {2013}
}
@article{faucris.120243464,
abstract = {In this work we focused on the reaction of water-soluble fullerene derivatives with various organic (i.e., methyl radical and t-butyl radical) and inorganic (i.e., superoxide radical and azide radical) radicals to mimic their superoxide dismutase (SOD) activity. Importantly, with the help of time-resolved pulse radiolysis and steady-state gamma radiolysis measurements all of the assays were conducted in aqueous solutions. Our fully-fledged spectroscopic and kinetic investigations leave no doubt about a diffusion-controlled addition mechanism (10 M s) by which superoxide radical reacts with fullerenes to yield (C-O) . Notable is that the formations of (C-CH), (C-(CH)(CH)COH), and (C -N) are much slower and proceed with activation-controlled rate constants less than 10 M s. The major deactivation path of (C-O ) is a pH dependent protonation (10 M s). Despite lacking unambiguous evidence for the formation of C - via a direct impact or an indirect dissociation mechanism - (C-O) is still redoxactive. The latter has been confirmed by an activation-controlled reduction (10 M s) of a series of p-benzoquinones that display different electron affinities. In other words, (C -O) - but not C - is likely to emerge as a key intermediate in the SOD activity of fullerenes. Its slow protonation is beneficial toward an efficient dismutation to form H O. © 2010 The Royal Society of Chemistry.},
author = {Kahnt, Axel and Guldi, Dirk Michael and Brettreich, Michael and Hartnagel, Uwe and Hirsch, Andreas},
doi = {10.1039/b917346n},
faupublication = {yes},
journal = {Journal of Materials Chemistry},
pages = {83-89},
peerreviewed = {Yes},
title = {{Reaction} of water-soluble fullerenes with {O2} - and other reactive radical species},
volume = {20},
year = {2010}
}
@article{faucris.201113196,
author = {Dürr, Maximilian and Klein, Johannes and Kahnt, Axel and Becker, Sabine and Puchta, Ralph and Sarkar, Biprajit and Ivanovic-Burmazovic, Ivana},
doi = {10.1021/acs.inorgchem.7b02192},
faupublication = {yes},
journal = {Inorganic Chemistry},
pages = {14912-14925},
peerreviewed = {Yes},
title = {{Redox} {Behavior} of a {Dinuclear} {Ruthenium}({II}) {Complex} {Bearing} an {Uncommon} {Bridging} {Ligand}: {Insights} from {High}-{Pressure} {Electrochemistry}},
volume = {56},
year = {2017}
}
@article{faucris.290209099,
abstract = {The regio- and stereocontrolled synthesis of fullerene bisadducts is a topic of increasing interest in fullerene chemistry and a key point for the full exploitation of these derivatives in materials science. In this context, while the tether-directed remote functionalization strategy offers a valid approach to this synthetic challenge, no examples of such control have yet been reported using nontethered species. Presented here is a conceptually novel, supramolecular-directed functionalization approach in which noncovalent interactions between untethered residues have been used, for the first time, to amplify (>2800-fold) the regio-, stereo-, and atropselective formation of a C60fullerene bisadduct racemate from a complex mixture of 130 bisadducts. Remarkably, both enantiomers, which present a sterically demanding cis-1 C60addition pattern, represent the first examples of fullerene derivatives which combine central, axial, and helical chirality.},
author = {Bottari, Giovanni and Trukhina, Olga and Kahnt, Axel and Frunzi, Michael and Murata, Yasujiro and Rodriguez-Fortea, Antonio and Poblet, Josep M. and Guldi, Dirk Michael and Torres, Tomas},
doi = {10.1002/anie.201602713},
faupublication = {yes},
journal = {Angewandte Chemie International Edition},
keywords = {atropisomerism; cycloaddition; fullerenes; phthalocyanines; supramolecular chemistry},
note = {CRIS-Team Scopus Importer:2023-03-07},
pages = {11020-11025},
peerreviewed = {Yes},
title = {{Regio}-, {Stereo}-, and {Atropselective} {Synthesis} of {C60Fullerene} {Bisadducts} by {Supramolecular}-{Directed} {Functionalization}},
volume = {55},
year = {2016}
}
@article{faucris.272769730,
abstract = {An unprecedented family of novel electron-donor acceptor conjugates based on fullerenes as electron acceptors, on one hand, and triphenyl amines as electron donors, on the other hand, have been synthesized and characterized in a variety of solvents using steady state absorption/emission as well as transient absorption spectroscopy. These are unprecedented in terms of their outcome of radical ion pair formation, that is, the singlet versus triplet excited state. This was corroborated by femto/nanosecond pump probe experiments and by molecular orbital calculations. Not only has the donor strength of the triphenylamines been systematically altered by appending one or two sulfur rich dithiafulvenes, but the presence of the latter changed the nature of the radical ion pair state. Importantly, depending on the excitation wavelength, that is, either where the fullerenes or where the triphenylamines absorb, short-lived or long-lived radical ion pair states, respectively, are formed. The short-lived component with a lifetime as short as 6 ps has singlet character and stems from a fullerene singlet excited state precursor. In contrast, the long-lived component has a lifetime of up to 130 ns in THF, has triplet character, and evolves from a triplet excited state precursor. Key in forming more than three orders of magnitude longer lived radical ion pair states is the presence of sulfur atoms, which enhance spin-orbit coupling and, in turn, intersystem crossing. Independent confirmation for the singlet versus triplet character came from temperature dependent measurements with a focus on the radical ion pair state lifetimes. Here, activation barriers of 2.4 and 10.0 kJ mol-1 for the singlet and triplet radical ion pair state, respectively, were established.},
author = {Saha, Avishek and Chen, Muqing and Lederer, Marcus and Kahnt, Axel and Lu, Xing and Guldi, Dirk Michael},
doi = {10.1039/C6SC03207A},
faupublication = {yes},
journal = {Chemical Science},
note = {CRIS-Team Scopus Importer:2022-04-14},
pages = {1360-1368},
peerreviewed = {Yes},
title = {{Sulfur} rich electron donors-formation of singlet versus triplet radical ion pair states featuring different lifetimes in the same conjugate},
volume = {8},
year = {2017}
}
@article{faucris.120399884,
abstract = {Here, we show that the synergistic interplay between two binding equilibria, acting at different sites of a (Zn)phthalocyanine-amidine molecule (Pc1), enables the dissociation of the photoinactive phthalocyanine dimer (Pc1) into a three-component system, in which a sequence of light harvesting, charge separation, and charge shift is successfully proven. The aforementioned dimer is assembled by dual amidine-Zn(II) coordination between neighboring Pc1 molecules and gives rise to high association constants (K ≈ 10 M). Such extraordinary stability hampers the individual binding of either carboxylic acid ligands through the amidine group or pyridine-type ligands through the Zn(II) metal atom to (Pc1). However, the combined addition of both ligands, which cooperatively bind to different sites of Pc1 through distinct noncovalent interactions, efficiently shifts the overall equilibrium toward a photoactive tricomponent species. In particular, when a fullerene-carboxylic acid (C A) and either a dimethylamino-pyridine (DMAP) or a phenothiazine-pyridine ligand (PTZP) are simultaneously present, the photoactivity is turned on and evidence is given for an electron transfer from photoexcited Pc1 to the electron-accepting CA that affords the DMAP-Pc1-CA or PTZP-Pc1 -CA radical ion pair states. Only in the latter case does a cascade of photoinduced electron transfer processes afford the PTZP-Pc1-CA radical ion pair state. The latter is formed via a thermodynamically driven charge shift evolving from PTZP-Pc1- CA and exhibits lifetimes that are notably longer than those of DMAP-Pc1-CA. © 2013 American Chemical Society.},
author = {Garcia-Iglesias, Miguel and Peuntinger, Katrin and Kahnt, Axel and Krausmann, Jan and Vazquez, Purificacion and Gonzalez-Rodriguez, David and Guldi, Dirk Michael and Torres, Tomas},
doi = {10.1021/ja410114d},
faupublication = {yes},
journal = {Journal of the American Chemical Society},
pages = {19311-19318},
peerreviewed = {Yes},
title = {{Supramolecular} assembly of multicomponent photoactive systems via cooperatively coupled equilibria},
volume = {135},
year = {2013}
}
@article{faucris.117623924,
abstract = {To optimize electron transfer and optoelectronic properties in nanoparticulate thin films for electronics we show the surface functionalization of ZnO nanorods by means of replacing surface active 2-[2-(2-methoxyethoxy) ethoxy]acetic acid (TODA) by a redoxactive organic component, that is, 5,10,15,20-(phenoxyacetat)-porphyrin bearing four carboxylic acids as possible ZnO anchors. Microscopy-transmission electron microscopy-And spectroscopy-optical spectroscopy-verifies the successful and homogenous integration of the porphyrin onto the surface of ZnO nanorods, a process that is facilitated by the four anchoring groups. Photophysical investigations based on emission and absorption spectroscopy prompt to distinct electronic interactions between ZnO nanorods and the porphyrins. Consequently, we performed further photophysical studies flanked by pulse radiolysis assays to corroborate the nature of the electronic interactions. © 2014 American Chemical Society.},
author = {Klaumünzer, Martin and Kahnt, Axel and Burger, Alexandra and Mackovic, Mirza and Muenzel, Corinna and Srikantharajah, Rubitha and Spiecker, Erdmann and Hirsch, Andreas and Peukert, Wolfgang and Guldi, Dirk Michael},
doi = {10.1021/am5004552},
faupublication = {yes},
journal = {ACS Applied Materials and Interfaces},
pages = {6724-6730},
peerreviewed = {unknown},
title = {{Surface} functionalization and electronic interactions of {ZnO} nanorods with a porphyrin derivative},
volume = {6},
year = {2014}
}
@article{faucris.121150744,
abstract = {Two new functionalized 4,4-disubstituted 2,2-bipyridines that were end-capped with cyanoacrylic acid or cyanoacrylic acid ester anchoring groups, which might allow their efficient functionalization on TiO2 or other metal-oxide semiconductor surfaces, have been synthesized and characterized by electrochemical, photophysical, and spectroscopic measurements. The electrochemical and photophysical properties of these 4,4-disubstituted 2,2-bipyridines with extended systems, in particular their LUMO energies, make them promising candidates to build up inorganic-organic hybrid photosensitizers for the sensitization of metal-oxide semiconductors (e.g., TiO2 nanoparticles and/or nanotubes).},
author = {Fingerhut, Anja and Wu, Yanlin and Kahnt, Axel and Bachmann, Julien and Tsogoeva, Svetlana},
doi = {10.1002/asia.201501324},
faupublication = {yes},
journal = {Chemistry-An Asian Journal},
keywords = {adsorption;bipyridines;conjugation;fluorescence;photosensitizers},
pages = {1232-1239},
peerreviewed = {Yes},
title = {{Synthesis} and {Electrochemical} and {Photophysical} {Characterization} of {New} 4,4-{Conjugated} 2,2-{Bipyridines} that are {End}-{Capped} with {Cyanoacrylic} {Acid}/{Ester} {Groups}},
volume = {11},
year = {2016}
}
@article{faucris.120236864,
abstract = {A series of three novel ZnPc-C conjugates (Pc = phthalocyanine) 1a-c bearing different spacers (single, double, and triple bond) between the two electroactive moieties was synthesized and compared to that of ZnPc-C conjugate 2, in which the two electroactive moieties are linked directly. The synthetic strategy - towards the preparation of 1a-c - involved palladium-catalyzed cross-coupling reactions over a monoiodophthalocyanine precursor 4 to introduce the corresponding spacer, and subsequent dipolar cycloaddition reaction to C . Detailed photophysical investigations of 1a-c and 2 prompted an intramolecular electron transfer that evolves from the photoexcited ZnPc to the electron-accepting C . In particular, with the help of femtosecond laser photolysis charge separation was indeed confirmed as the major deactivation channel. Complementary time-dependent density functional calculations supported the spectral assignment, namely, the spectral identity of the ZnPc radical cation and the C radical anion as seen in the differential absorption spectra. The lifetimes of the correspondingly formed radical ion-pair states depend markedly on the solvent polarity: they increase as polarity decreases. Similarly, although to a lesser extent, the nature of the linker impacts the lifetime of the radical ion-pair states. In general, the lifetimes of these states tend to be shortest in the system that lacks any spacer at all (2), whereas the longest lifetimes were found in the system that carries the triple-bond spacer (1a). © 2008 Wiley-VCH Verlag GmbH & Co. KGaA.},
author = {Quintiliani, M. and Kahnt, Axel and Wölfle, Thorsten and Hieringer, Wolfgang and Vázquez, P. and Görling, Andreas and Guldi, Dirk Michael and Torres, T.},
doi = {10.1002/chem.200701700},
faupublication = {yes},
journal = {Chemistry - A European Journal},
pages = {3765-3775},
peerreviewed = {Yes},
title = {{Synthesis} and photoinduced electron-transfer properties of phthalocyanine-[60]fullerene conjugates.},
volume = {14},
year = {2008}
}
@article{faucris.272771743,
abstract = {Sulfur-containing molecules participate in many essential biological processes. Of utmost importance is the methylthioether moiety, present in the proteinogenic amino acid methionine and installed in tRNA by radical-S-adenosylmethionine methylthiotransferases. Although the thiol–ene reaction for carbon–sulfur bond formation has found widespread applications in materials or medicinal science, a biocompatible chemo- and regioselective hydrothiolation of unactivated alkenes and alkynes remains elusive. Here, we describe the design of a general chemoselective anti-Markovnikov hydroalkyl/aryl thiolation of alkenes and alkynes—also allowing the biologically important hydromethylthiolation—by triplet–triplet energy transfer activation of disulfides. This fast disulfide–ene reaction shows extraordinary functional group tolerance and biocompatibility. Transient absorption spectroscopy was used to study the sensitization process in detail. The hereby gained mechanistic insights were successfully employed for optimization of the catalytic system. This photosensitized transformation should stimulate bioimaging applications and carbon–sulfur bond-forming late-stage functionalization chemistry, especially in the context of metabolic labelling.},
author = {Teders, Michael and Henkel, Christian and Anhaeuser, Lea and Strieth-Kalthoff, Felix and Gomez-Suarez, Adrian and Kleinmans, Roman and Kahnt, Axel and Rentmeister, Andrea and Guldi, Dirk Michael and Glorius, Frank},
doi = {10.1038/s41557-018-0102-z},
faupublication = {yes},
journal = {Nature chemistry},
note = {CRIS-Team Scopus Importer:2022-04-14},
pages = {981-988},
peerreviewed = {unknown},
title = {{The} energy-transfer-enabled biocompatible disulfide–ene reaction},
volume = {10},
year = {2018}
}