Ilia V. Eltsov

Supramolecular architecture of betulin diacetate complexes with arabinogalactan from Larix sibirica.

Supramolecular ensembles of arabinogalactan (AG) and its complexes with betulin diacetate (BDA) were studied in water and dimethyl sulfoxide (DMSO) using ablation, induced by submillimeter radiation from the free electron laser. Solutions of 1wt% AG resulted in formation of aerosol particles with a maximum size of 60-70nm. In contrast, with DMSO as the solvent, the majority of particles were significantly smaller. Nevertheless, the addition of water shifted the particle size distribution to a larger size, suggesting the cross-linking of AG chains due to hydrogen bonding through water molecules. The ensembles of molecules were larger in solutions of the AG-BDA complex as compared to pure AG aqueous solution, and the distribution was narrow. The role of side chain interactions in the formation of AG-BDA complexes in aqueous solutions was confirmed by NMR.

Two alternative approaches to modification of a cage complex: nucleophilic substitution and electrophilic addition for the synthesis of an iron(II) clathrochelate with an annulated imidazole fragment

A rib-functionalized iron(II) tris-dioximate clathrochelate bearing an annulated phenylimidazole fragment was prepared using nucleophilic substitution and electrophilic addition at the chelating α-dioximate fragment of the macrobicyclic framework. The resultant cage complex was identified with single crystal XRD, analytical data, 1H, 13C, 19F, 11B NMR spectroscopy, and examined with UV–vis spectroscopy and CVA. Two approaches to modification of the clathrochelate framework are compared. Graphical abstract

Synthesis, structure and luminescence properties of new chalcogenide octahedral rhenium cluster complexes with 4-aminopyridine [{Re6Q8}(4-NH2-py)6]2+

Abstract Two new cationic octahedral rhenium cluster complexes [{Re6Q8}(4-NH2-py)6]2+ (Q=S, Se; 4-NH2-py = 4-aminopyridine) were synthesized by reactions of cesium salts of cluster anions [{Re6Q8}Br6]4−/3− with molten 4-aminopyridine. Both complexes were separated as salts with Br− as counterions and the structure of [{Re6S8}(4-NH2-py)6]Br2·6DMF was revealed by X-ray single-crystal diffraction analysis. The compounds were characterized by elemental analysis, energy dispersive X-ray, IR, NMR, and luminescence spectroscopies.

Iron(II) clathrochelate with an annelated 4,5-dimercapto-[1,3]dithiol-2-thione moiety: Synthesis, structure, and redox reactions

Nucleophilic substitution of chlorine atoms in iron(II) dichloroclathrochelate induced by 4,5-dimercapto-[1,3]dithiol-2-thione dianion gave rise to a cage complex with an annelated sulfur-containing heterocyclic moiety. The composition and structure of this complex were determined by X-ray crystallography and multinuclear NMR spectroscopy in a crystal and in solution, respectively; cyclic voltammetry (CVA) and EPR were used to study the redox reactions of the complex in solution to yield a ligand-centered radical-anionic product.

1-Alkyl-3-methylimidazolium 4-organyloxy-2,3,5,6-tetrafluorophenyltrifluoroborates as a new platform for ionic liquids with specific properties

A new synthetic platform for ionic liquids (ILs) with specific properties was suggested based on the polyfluorophenyltrifluoroborate anions, Q[4-XC6F4BF3] (X = F, RO). Convenient preparative approaches to these ILs including the ones with chiral counteranions were developed. The dependence of physicochemical properties of ILs on the nature of substituents in the fluorinated ring was studied.

From photoinduced to dark cytotoxicity via an octahedral cluster hydrolysis

Octahedral molybdenum and tungsten clusters have potential biological applications in photodynamic therapy and bioimaging. However, poor solubility and hydrolysis stability of these compounds hinder their application. The first water-soluble photoluminescent octahedral tungsten cluster [{W6 I8 }(DMSO)6 ](NO3 )4 was synthesised and demonstrated to be at least one order of magnitude more stable towards hydrolysis than its molybdenum analogue. Biological studies of the compound on larynx carcinoma cells suggest that it has a significant photoinduced toxicity, while the dark toxicity increases with the increase of the degree of hydrolysis. The increase of the dark toxicity is associated with the in situ generation of nanoparticles that clog up the cisternae of rough endoplasmic reticulum.