Hybrid Molecules Based on Fullerene C60 and Dithienylethenes. Synthesis and Photochromic Properties. Optically Controlled Organic Field-Effect Transistors.

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.

Synthesis of fullerenyl-1,2,3-triazoles by reaction of fullerenyl azide with terminal acetylenes.

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.

Synthesis and cytotoxic activity of unsaturated macrolides and their hybrid molecules with a C60 fullerene.

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.

Hybrid molecules based on fullerene C60 and 5Z,9Z-dienoic acids: Synthesis and cytotoxic activity.

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.

Synthesis and Electrochemical Properties of Fullerenylstyrenes.

An efficient preparative method was developed for the synthesis of previously unreported fullerenylstyrenes based on the reaction of C60 fullerene with terminal acetylenes and EtMgBr in the presence of Ti(Oi-Pr)4. The voltammetric curves of the prepared fullerenylstyrenes were studied, and good prospects for their application as acceptor materials for bulk heterojunction solar cell were demonstrated.

Photochromic systems with photoinduced emission modulation of colloidal CdSe quantum wells.

A spectroscopic study of photochromic systems containing two-dimensional CdSe nanoparticles (colloidal quantum wells) and photochromic compounds of the thermally relaxing chromene and thermally irreversible diarylethene classes in solutions was carried out. First, the systems were found to exhibit modulation of emission of two-dimensional nanoparticles in accordance with the photochromic transformations of compounds due to Förster resonance energy transfer (FRET) from the two-dimensional nanoparticles to photoinduced photochromic isomers.

Synthesis of C60 Fullerene-Quadricyclane Hybrid Compound and Its Preliminary In Vitro Antitumor Activity in Combination with Cisplatin.

This paper describes the authors' preliminary studies directed toward the possibility of the practical implementation of the idea to design efficient antitumor drugs based on hybrid molecules composed of fullerene C60 and quadricyclanes. The essence of the proposed idea is that these hybrid molecules are able to cleave DNA owing to the fullerene moiety they contain and to simultaneously thermally affect tumor cells via cleavage of the carbon-carbon bond in quadricyclanes under the action of Pd and Pt ions. As a result, testing of the cytotoxic activity in vitro for a number of fullerene C60 hybrids with the norbornadiene or quadricyclane moieties against the human T-lymphoblastic leukemia cells (Jurkat cells) in combination of the known cisplatin drug, which was taken as the source of Pt ions, showed a statistically reliable dose-dependent increase in the number of dead cells in each group, which were formed according to the amount of cisplatin added, in comparison with the control, that is, cells treated with cisplatin or quadricyclane fullerene derivatives alone. Indeed, the difference between the percentages of viable cells after treatment with either cisplatin alone or cisplatin in combination with methanofullerene 5 ranged from ∼10% (for Pt (0.015 mkM), 5 (0.015 mkM)) to ∼55% (for Pt (0.03 mkM), 5 (0.045 mkM)).

Synthesis and Properties of Energy-Rich Methanofullerenes Containing Norbornadiene and Quadricyclane Moieties.

The energy-rich methanofullerenes were synthesized for the first time by the reaction of fullerene C60 with mono- and bisquadricyclane esters of malonic acid. The C-C bond cleavage in the quadricyclane moieties of new hybrid molecules takes place in the presence of catalytic amounts of Cu, Pd, and Pt salts or complexes or SiO2 and is accompanied by heat evolution.

Aminomethylation of Fullerene C60 with N,N',N″-Triaryl- or N,N',N″-Trihetaryl-1,3,5-perhydrotriazines in the Presence of EtMgBr and Ti(Oi-Pr)4.

A new method for the functionalization of fullerenes based on the reaction between in situ generated aryl- or hetaryl-containing 1,3,5-perhydrotriazines and EtMgBr in the presence of Ti(Oi-Pr)4 has been developed. The cleavage of the triazine ring under previously developed conditions1-6 results in the formation of aminomethylated derivatives of fullerene C60 with high yields (80-90%) and selectivity (∼90%).

Inheritance of Photochromic Properties of Nitro-Substituted and Halogenated Spiropyrans Containing the Pyrrolidino[60]fullerene.

The photophysical and isomerization properties of hybrid molecular compounds that consist of photochromic nitro-substituted and halogenated spiropyran derivatives bonded to the surface of the [60]fullerene cage through the pyrrolidine bridge were investigated using various functionals and basis sets of TD-DFT and semiempirical quantum-chemical approaches. The role of nπ* states formed by the lone pairs of substituents in changing of the electronic structure and photochromic properties of spiropyran derivatives was evaluated. The Sππ(spiropyran) → intermediate nπ* states → Sππ(merocyanine) channel for phototransformation of the hybrid compound containing a nitro-substituted spiropyran moiety was established and compared with similar systems of halogenated spiropyrans attached to the [60]fullerene bulk where photoinduced isomerization does not process due to high probability of internal conversion from the excited electronic state localized on the spiropyran fragment to the states of the pyrrolidino[60]fullerene.

One-Pot Method for the Synthesis of 2,5-Unsubstituted Pyrrolidino[3',4':1,9]fullerenes.

A new, efficient process has been developed for the preparation of 2,5-unsubstituted pyrrolidino[3',4':1,9]fullerenes by the Ti(O-i-Pr)4-promoted reaction of fullerene C60 with 1,3,5-perhydrotriazines generated in situ upon the reaction of primary alkyl- and benzylamines with paraformaldehyde and EtMgBr.

Diastereotopic splitting in the 13C NMR spectra of sulfur homofullerenes and methanofullerenes with chiral fragments.

Using gauge-invariant atomic orbital PBE/3ζ quantum chemistry approach, (13)C NMR chemical shifts and diastereotopic splittings of sp(2) fullerenyl carbons of a number of sulfur homofullerenes and methanofullerenes have been predicted and discussed. An anisochrony of fullerene carbons is caused by a chiral center of attached moieties. Clearly distinguishable diastereotopic pairs (from 8 to 11) of fullerenyl carbons of homofullerenes were observed. Unambiguous assignments of (13)C NMR chemical shifts were performed, and diastereotopic splittings of methanofullerenes were observed for α, ß and γ to a functionalization site.

Homo- and methano[60]fullerenes with chiral attached moieties--1H and 13C NMR chemical shift assignments and diastereotopicity effects.

(1)H and (13)C NMR chemical shift predictions of homo- and methano[60]fullerenes containing chiral centers in attached fragment were made using the two-dimensional NMR technique (HH COSY, (1)H-(13)C HSQC and HMBC) and the quantum chemistry GIAO calculation method in the PBE/3ζ approach. The influence of a chiral substituent on the (13)C chemical shifts of diastereotopic fullerene carbons was estimated by comparing the calculated and experimental (13)C NMR spectra. The resonances of the fullerene carbons in α-, ß- and δ-positions relative to the position of the substituent exhibit the greatest diastereotopic splitting.