To Oleg Shishkin

Dr.Sc. in Chemistry, Acting General Director of the SSI “Institute for Single Crystals” of the National Academy of Sciences of Ukraine, Head of the Department of X-ray Diffraction Studies and Quantum Chemistry, an extraordinary man – Prof. Oleg Valeryevich Shishkin who passed away at the age of 47

First insights into the synthesis of carbo-phospholane and carbo-phospholene oxides

Fifteen-membered ring carbo-mers of five-membered rings are considered in the heterocyclic series of the phosphole oxide and less unsaturated parents. The synthesis of the first carbo-phospholane oxides is achieved by a [14+1] two-step/one-pot macrocyclization route with 86 % yield. Reduction of the latter phosphora-[5]pericyclyne with SnCl­2 allowed consistent 1H and 31P NMR characterization of the corresponding carbo-phospholene, produced with 11 % yield. The ultimate carbo-phosphole oxide could not be isolated, but preliminary results on alternative strategies towards this 14 pz-electron Hückel carbo-aromatic are reported.

7th International Scientific Conference in Chemistry ‘Kiev-Toulouse’

7th International Scientific Conference in Chemistry Kiev-Toulouse was held June 2-7, 2013 at the Department of Chemistry of the National Taras Shevchenko University of Kiev (KNU)

Towards fluorescent indolyl-carbo-benzenes

The C18 macro-aromatic carbo-benzene core is a strong chromophoric unit resembling the porphine ring which is prone to quench the emission of fluorophoric substituents. Within the aim of preparing fluorescent carbo-benzenes (and carbo-cyclohexadiene parents) for measurement of their two-photon absorption cross-section by the TPEF method, several indole derivatives were devised and anchored to the C18 macrocycle either directly, p-phenylogously or ethynylogously. Synthesis methodology and spectroscopical measurements are presented in a comparative prospec

First example of ring carbomer of 1,4-cyclohexadiene

While a series of carbo-mers of 1,3-cyclohexadienes was reported through the use of a specifically developed synthetic strategy, no example of their 1,4-regioisomers was known. Inspired by the methodology elaborated for the preparation of the 1,3-isomers, the synthesis of the first example of carbo-mer of 1,4-cyclohexadiene is presented. Comparison of physico-chemical properties of this first representative with those of the recently described 1,4-regioisomer, especially UV-vis absorption properties, is also addressed

En route to a dianilinyl-substituted carbo-cyclohexadiene with promising electrical properties

The macro-aromatic carbo-benzene core para-disubstituted by 4-anilinyl groups is known to be an efficient single-molecule conductor, exhibiting a conductance of 106 nS measured by the scanning tunneling microscopy-break junction technique. The linear carbo-butadiene analogue bearing the same anilinyl substituents was found to be less efficient, with a conductance of 2.7 nS. The reason of this difference could be elucidated through the study of the charge transport properties of a cyclically locked carbo-butadiene core in a carbo-cyclohexadiene derivative. In this paper, advances in the synthesis of this challenging dianilinyl-substituted carbo-cyclohexadiene are presented

A difluorenyl-carbo-cyclohexadiene: prospective chromophore for two-photon absorption

For the purpose of outlining structure-property relationships for two-photon absorption (2PA), a "s-locked" carbo-cyclohexadiene with two fluorenyl substituents has been envisaged for comparison with previously studied aromatic carbo-benzene and non-aromatic carbo-quinoid congeners. A representative where the C10-π-conjugated fluorenyl moieties are also connected by a C8-π-insulating 3,6‐dimethoxy‐3,6‐bis(trifluoromethyl)octa‐1,4,7‐triyn-1,8-diyl edge has thus been synthesized in four steps from known C8F triyne and C10 triynyldial, through a [8F+10] cyclization process. In spite of a relatively strong absorbance (e = 84 800 L.mol-1.cm-1 at 634 nm), the non-vanishing green fluorescence (at 533 nm) of the chromophore should allow measurements of the 2PA cross section by both the TPEF and Z-scan methods

Fluorinated analogues of lipidic dialkynylcarbinol pharmacophores: synthesis and cytotoxicity in HCT116 cancer cells

Lipidic alkynylcarbinols (LACs) have been identified as potential antitumor compounds, and a thorough understanding of their pharmacophoric environment is now required to elucidate their biological mode of action. In the dialkynylcarbinol (DAC) series, a specific study of the pharmacophore potential has been undertaken by focusing on the synthesis of three fluorinated derivatives followed by their biological evaluation. This work highlights the requirement of an electron-rich secondary carbinol center as a key structure for cytotoxicity in HCT116 cells