Tatyana V. Rybalova

Optically active ZnII and PtII complexes of the 3-carene type α-amino oxime

Abstract (1S,3S,6R)-3- N,N- Dimethylaminocaran-4-one E-oxime forms stable 1:1 chelate complexes with ZnCl2 and PtCl2 whose structures are supported by X-ray, 1H, 13C, 14N and 195Pt NMR data. The conformation of the six-membered carbon cycle in the complexes was found to be changed as compared to the starting compound.

Highly-emissive solution-grown furan/phenylene co-oligomer single crystals

Solution-processed furan/phenylene co-oligomer single crystals combine high photoluminescence quantum yield (>65%) and efficient charge transport (mobility 0.12 cm2 V−1 s−1) making them promising materials for printable organic optoelectronics.

Methyl substituent effect on structure, luminescence and semiconducting properties of furan/phenylene co-oligomer single crystals

Single crystals of furan/phenylene co-oligomers are among the most promising highly-emissive materials for applications in various optoelectronic devices. In this work, we synthesized and studied furan/phenylene co-oligomers with the same conjugated core 1,4-bis(5-phenylfuran-2-yl)benzene and methyl substituents at p- and m-positions of the terminal phenyls. The effect of substituents on the crystal packing, charge transport and luminescence of the single crystals was studied. Compared to the unsubstituted compound, the methyl-substituted co-oligomers demonstrated improved thermostability and enhanced photoluminescence, which we assign to J-aggregation resulting from the strong inclination of the molecules against the main crystal facet. The charge mobility in single crystal organic field-effect transistors decreased upon the inclination of the molecules. We conclude that the molecular tilt angle, intermolecular distances and interactions in crystals of heteroaryl-containing linear conjugated oligomers can be controlled by the introduction of end methyl groups in the appropriate positions.

Molecular Rearrangements of (-)-α-Cedrene in Superacids

Abstract The (-)-α-cedrene was for the first time rearranged into isomeric compounds with the zizaane and patchoulane skeletons. The possible mechanisms of carbocationic rearrangements were studied by methods of molecular mechanics with the use of the ICAR software .

Isomerization as a tool to design volatile heterometallic complexes with methoxy-substituted β-diketonates

Abstract A series of new heterometallic compounds have been obtained by the co-crystallization of Cu(II) methoxy-substituted β-diketonates and Pb(II) hexafluoroacetylacetonate (hfac) from organic solvents. Their crystal structures were established by X-ray analysis. It is shown that the formation of heterometallic compounds proceeds with geometrical isomerization of the initial copper complexes, which can be controlled by varying terminal substituents in the ligand. Due to the ability of copper complexes to isomerize, the structure of the resulting heterocomplexes can be flexibly and purposefully changed from polymeric to discrete molecular forms. The study of the thermal properties shows that all the reported compounds are volatile and can be re-sublimed in a vacuum, with their composition and structure being retained.

Long-Range Exciton Transport in Brightly Fluorescent Furan/Phenylene Co-oligomer Crystals

The design of light-emitting crystalline organic semiconductors for optoelectronic applications requires a thorough understanding of the singlet exciton transport process. In this study, we show that the singlet exciton diffusion length in a promising semiconductor crystal based on furan/phenylene co-oligomers is 24 nm. To achieve this, we employed the photoluminescence quenching technique using a specially synthesized quencher, which is a long furan/phenylene co-oligomer that was facilely implanted into the host crystal lattice. Extensive Monte-Carlo simulations, exciton–exciton annihilation experiments and numerical modelling fully supported our findings. We further demonstrated the high potential of the furan/phenylene co-oligomer crystals for light-emitting applications by fabricating solution-processed organic light emitting transistors.

Enantioselective Benzylic Hydroxylation of Arylalkanes with H2O2 in Fluorinated Alcohols in the Presence of Chiral Mn Aminopyridine Complexes

A series of chiral bioinspired Mn‐aminopyridine complexes of the type [L*MnII(OTf)2] (where L* is 2,2′‐bipyrrolidine derived ligand, bearing trifluoroalkoxy and alkyl substituents) have been tested as catalysts in benzylic C−H hydroxylation of arylalkanes with H2O2 in fluorinated ethanols media. In 2,2,2‐trifuoroethanol, the yield of the target ethylbenzene oxidation product, chiral 1‐phenylethanol, reaches 45u2009%, which is much better than in the common solvent CH3CN (5‐6u2009%). The selectivity for 1‐phenylethanol formation increases in the following order: CH3CN<2‐fluoroethanol<2,2‐difluoroethanol<2,2,2‐trifuoroethanol, while 2,2‐difluoroethanol ensures the highest asymmetric induction in this series, affording chiral benzylic alcohols with up to 89u2009% ee. In trifluoroethanol, the observed primary kH/kD value of 2.3 has been measured for the oxidation of 1‐phenylethanol/α‐D‐1‐phenylethanol, which is similar to that in CH3CN (2.2). At the same time, depending on the solvent, CH3CN or 2,2,2‐trifuoroethanol, the oxidations of 1‐phenylethanol demonstrates drastically different linear free‐energy relationships; possible effect of the hydrogen‐bond donor (HBD) nature of CF3CH2OH is discussed in this context. Noticeably, it has been shown that by switching the absolute chirality ((S,S)− or (R,R)−) of the catalyst, the oxidation of complex substrate of natural origin, estrone acetate, can be diverted to predominant formation of either the tertiary C9‐alcohol or of the C6‐ketone, respectively.

CCDC 1520469: Experimental Crystal Structure Determination

Related Article: Maxim S. Kazantsev, Alina A. Beloborodova, Ekaterina S. Frantseva, Tatyana V. Rybalova, Vladislav G. Konstantinov, Inna K. Shundrina, Dmitry Yu. Paraschuk, Evgeny A. Mostovich|2017|CrystEngComm|19|1809|doi:10.1039/C6CE02565J

CCDC 1520470: Experimental Crystal Structure Determination

Related Article: Maxim S. Kazantsev, Alina A. Beloborodova, Ekaterina S. Frantseva, Tatyana V. Rybalova, Vladislav G. Konstantinov, Inna K. Shundrina, Dmitry Yu. Paraschuk, Evgeny A. Mostovich|2017|CrystEngComm|19|1809|doi:10.1039/C6CE02565J

Cytotoxic and cancer preventive activity of benzotrithioles and benzotrithiole oxides, synthetic analogues of varacins

The cytotoxic and cancer preventive activities of synthetic analogs of natural varacins with polysulfide groups were studied. Presence of a sulfoxide group was found to have no significant effect on the cytotoxicity of these compounds. At the same time, this group is important for inhibition of colony formation of tumor cells treated with tumor promoter thus demonstrating cancer preventive activity. The most promising compound appears to be a synthetic varacin C analog, sulfoxide 10a, which exhibits the cancer preventive activity at dose into 100 times lower than its cytotoxic concentrations.