Reversible transformations of a hybrid molecule based on [60]fullerene and a spiropyran moiety under conditions of combined photo- and electrochemical exposure were found. It has been established that the electrochemical oxidation of the UV-photoinduced colored form of the hybrid spiropyran in solution significantly accelerates the discoloration process and does not affect the fullerene part of the hybrid molecule. The research results are promising for designing a photo-electrochromic device that modulates electromagnetic radiation in the visible range of the spectrum.
A comparative spectral study of water–acetonitrile systems containing photochromic spiropyran and spirooxazine derivatives in the absence and in the presence of silica nanoparticles was carried out. The photoinduced formation of proton complexes beetwen phenolic oxygen of the colored forms of spirocompounds and the surface hydroxyl groups of silica nanoparticles was established for all of the derivatives. The photoinduced proton complexes of the spiropyrans exhibit positive photochromism on the surface of silica nanoparticles. It is assumed that the previously discovered negative photochromism is due to the formation of proton complexes with not only phenolic oxygen, but also the OH group at the nitrogen atom of the indoline spiropyran moiety. These complexes can also exist in the absence of nanoparticles, because of interaction with water molecules.
The data obtained by the authors in the field of carbon cluster chemistry, namely, the catalytic cycloaddition of diazo compounds of modern pharmacologically significant and natural compounds to C60-fullerene under the action of complex Pd–catalysts, are summarized. Cycloaddition reactions of diazoacetates, diazoamides, and diazoketones with C60-fullerene, catalyzed by Pd(acac)2–PPh3–Et3Al, with the selective formation of methano– and pyrazolinofullerenes, are new and promising classes of biologically active derivatives of C60-fullerenes.
The results of studies of the spectral-kinetic (absorption and fluorescent) characteristics of the polymer nanospheres created by us (containing luminescent inorganic CdSe/ZnS quantum dots and photochromic diarylethene molecules) incorporated into a polymer film are presented. A reversible modulation of the fluorescence intensity of quantum dots, caused by the photoisomerization of diarylethene molecules, was found. It is shown that nanospheres in polymer matrices exhibit higher efficiencies of both photoinduced modulation of QD radiation and Forster resonance energy transfer (FRET) from QDs to the cyclic isomer of DAE as compared to solutions. The results can be used, for example, to create luminescent photocontrolled panels based on films containing fluorescent nanoparticles. Keywords: photochromism, fluorescence, quantum dot, Forster resonance energy transfer, polymer nanospheres, polymer films
The data obtained by the authors in the field of carbon cluster chemistry, namely the catalytic cycloaddition of sulfur-containing diazo compounds to C60-fullerene under the action of complex Pd catalysts, are summarized. Cycloaddition reactions of diazoalkanes, diazoketones, and diazothioates with C60-fullerene, catalyzed by Pd(acac)2–PPh3–Et3Al, with the selective formation of new sulfur-containing methano-, homo-, and pyrazolinofullerenes, are promising as modern nanosized additives in oils for highly loaded mechanisms.
The results of studies of the spectral-kinetic (absorption and fluorescent) characteristics of the polymer nanospheres created by us (containing luminescent inorganic CdSe/ZnS quantum dots and photochromic diarylethene molecules) incorporated into a polymer film are presented. A reversible modulation of the fluorescence intensity of quantum dots, caused by the photoisomerization of diarylethene molecules, was found. It is shown that nanospheres in polymer matrices exhibit higher efficiencies of both photoinduced modulation of QD radiation and Förster resonance energy transfer (FRET) from QDs to the cyclic isomer of DAE as compared to solutions. The results can be used, for example, to create luminescent photocontrolled panels based on films containing fluorescent nanoparticles.
Spectral and kinetic studies of the interaction of the surface groups of graphene oxide nanoplatelets with the molecules of photochromic compounds from the classes of chromenes and spiropyrans in solutions were carried out. It was shown that the interaction of the surface hydroxy groups of graphene oxide with the spiropyran molecules led to the formation of protonated complexes exhibiting negative photochromism. In the case of chromene, spectrally less pronounced interactions were detected, presumably due to physical adsorption of the molecules on the surface of the graphene oxide nanoplatelets.
Through the reaction of fullerenylazide with terminal acetylenes, previously undescribed 1-butyl-2-triazolylfullerenes, in which the heterocyclic fragment was directly attached to the fullerene backbone, were synthesized for the first time. Water-soluble complexes of the synthesized adducts of fullerene with polyvinylpyrrolidone showed a high cytotoxic activity towards tumor cells of the Jurkat, K562, and U937 lines.
Hybrid molecules based on fullerene C60 and dithienylethene and its perfluorinated analog not inferior in the efficiency of phototransformations to the initial photochromic compounds were synthesized for the first time. The resulting pyrrolidinofullerenes containing photochromic moieties were used to fabricate organic field-effect transistors (OFETs) with output and transfer characteristics ten times exceeding similar characteristics of devices based on staring dithienylethenes. It was found that OFETs based on hybrid molecules with dithienylethenes are four times less efficient than devices based on hybrid molecules with perfluorinated analogs.
A novel approach for introducing strained 2,3-dimethylenebicyclo[2,2,0]hexane structures into the C60 fullerene molecule, based on the reaction of C60 with substituted propargylamines, promoted by the Ti(Oi-Pr)4 and EtMgBr system.
The Bingel–Hirsch reaction was used to synthesize two new hexamethanofullerenes containing six quadricyclane fragments. Preliminary experiments have established that the synthesized compounds have a high antitumor effect in combination with cisplatin on human T-lymphoblastic leukemia cells (Jurkat cells).
Organic field-effect transistors with styryl fullerene as a semi conductor layer applied by centrifugation are considered. Electron mobility in the transistors was 0.067 ± 10% cm2 V−1 s−1, whereas the mobility of electrons in these devices after the vacuum deposition of a semiconductor layer was much lower (0.023 ± 10% cm2 V−1 s−1).
Previously unreported macrodiolides containing a 1Z,5Z-diene fragment in the structure have been synthesized with high yields and stereoselectivity by our research group, using the intermolecular esterification of malonic acid with α,ω-diols containing bis-methylene-separated Z-double bonds, catalyzed by Hf(OTf)4 hafnium triflate. Under Bingel-Hirsch conditions, the synthesized macrodiolides were chemically bonded with a C60 fullerene to produce the corresponding methanofullerenes. The cytotoxic activity of macrodiolides and methanofullerenes in relation to Jurkat, K562, U937, HL60 tumor cell lines and normal fibroblasts was studied. Covalent binding of macrodiolides to the C60 fullerene molecule was found to significantly increase the cytotoxic effect (from 5 to 170 times) of the hybrid molecule as compared to the initial macrodiolide. Moreover, the synthesized hybrid molecules initiate apoptosis by uncoupling oxidation and phosphorylation of the mitochondrial membrane of tumor cells.
Fullerenyltriazoles were synthesized by the interaction of azidofullerene with terminal acetylenes, in which the heterocyclic fragment is directly attached to the fullerene core. The electrochemical studies of the synthesized triazole-containing fullerenes have proved that the potentials of the first reduction peaks are shifted to a less cathodic region compared to unmodified C60. According to theoretical calculations, synthesized fullerene C60 derivatives can be considered as promising acceptor components of organic solar cells.
The review summarizes for the first time the results of reported experimental and theoretical studies on the synthesis of fullerenes and their derivatives, their antiwear and extreme pressure properties, and modern areas of application as dry lubricants and greases or oil additives for various purposes. Methods for synthesizing fullerene derivatives and correlations between their structure and tribological characteristics have been considered.
We prepared for the first time photoactive colloidal nanospheres consisting of hydrophobic CdSe/ZnS core-shell quantum dots encapsulated in an amphiphilic PMAT polymeric shell containing photochromic diarylethene DAE1 with stoichiometry of similar to 6 dye molecules per single quantum dot. The UV-induced photoisomerization of DAE1 molecules results in the partial quenching of the quantum dot emission due to FRET from the quantum dot to DAE1 photoisomer with its absorption band spectrally overlapped with the quantum dot emission. The modulation of the quantum dot emission is reversible under cyclic UV-vis-induced open-closed photoisomerization of DAE1.
Hybrids composed of 3-pentylnorbornadiene-2-carboxylic acid or its quadricyclane isomer molecules linked to methano-C60 fullerene via triethylene glycol spacer were synthesized by the Bingel–Hirsch reaction. The quadricyclane derivative possesses markedly higher apoptosis-inducing activity against the Jurkat tumor cells than the norbornadiene one.
Spiropyran-containing methanofullerenes able to rapidly and reversibly respond to optical and chemical stimuli were synthesized for the first time by the Bingel-Hirsch reaction and catalytic cycloaddition of diazo compounds to carbon clusters. The effects of substituent structure in the new hybrid molecule and the mode of spiropyran attachment to fullerene on the spectral kinetic properties and photo- and acidochromic behavior of the synthesized fullerene derivatives was established.
The present research project details synthesis of new hybrid methanofullerenes based on acetylene and triazole esters of malonic acid containing 5Z,9Z-dienoic acids and fullerene C60 under Bingel-Hirsch conditions, including study of the cytotoxic activity with respect to Jurkat, K562, U937 and HL60 tumor cell lines. Hybrid methanofullerenes containing acetylenic fragments, unlike triazole substituents, were found to exhibit higher cytotoxicity, but are characterized by lower selectivity of action in relation to healthy cells.