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The first metallasilsesquioxane bearing pyrazolylpyridine ligands, the Cu 8 -based complex 1, adopts a cage-like structure with two zigzag-type copper tetramers sandwiched by two cyclic Si 5 silsesquioxane ligands. The four 3-phenyl-5-(2-pyridyl)pyrazolate ligands in 1 exhibit dual (chelating and bridging) modes of ligation. Compound 1 is very active in the oxidation of alkanes and alcohols.

We report a high nuclear (Cu 14 ) complex synthesized via the self-assembly of copper-methylsilsesquioxane induced by the complexation with 1,2-bis(diphenylphosphino)ethane (dppe). The structure includes two cationic Cu I (dppe) 2 moieties and an anionic silsesquioxane cage of an unprecedented Cu II 12 structural type. The Cu 12 cage fragment exhibits a unique ( i ) combination of Si 4 -cyclic/Si 2 -acyclic silsesquioxane ligands and ( ii ) encapsulation of two different chloride and carbonate species. This complex acts as a promising precatalyst in the mild oxidation and carboxylation of light alkanes to produce alkyl hydroperoxides, alcohols, ketones, or carboxylic acids. The present study widens the family of copper-methylsilsesquioxane clusters with prospective use in oxidation catalysis.

An extended ( i.e. , 19 distinct species) family of cage-like Cu 4 -phenylsilsesquioxanes allowed us to accentuate the general regularities behind their structural organization. Influencing factors, namely the (i) size of external alkali metal ions (from Li to Cs) and (ii) nature of bridging linkers (including the smallest possible ones, like a water molecule) on the self-assembly/supramolecular assembly of such Cu 4 -building blocks have been thoroughly explored. A Cu 4 K 4 -based complex has been evaluated as a precatalyst in the oxidation of alkanes (cyclohexane, n -heptane, methylcyclohexane) and alcohols. The experimental evidence that radical species participate in the oxidation of alkanes is provided.

Convenient self-assembly synthesis of copper(II) complexes via double (phenylsilsesquioxane and acetate) ligation allows to isolate a family of impressive sandwich-like cage compounds. An intriguing feature of these complexes is the difference in the structure of a pair of silsesquioxane ligands despite identical (Cu 6 ) nuclearity and number (four) of acetate fragments. Formation of particular combination of silsesquioxane ligands (cyclic/cyclic vs condensed/condensed vs cyclic/condensed) was found to be dependent on the synthesis/crystallization media. A combination of Si 4 -cyclic and Si 6 -condensed silsesquioxane ligands is a brand new feature of cage metallasilsesquioxanes. A representative Cu 6 -complex (4) (with cyclic silsesquioxanes) exhibited high catalytic activity in the oxidation of alkanes and alcohols with peroxides. Maximum yield of the products of cyclohexane oxidation attained 30 %. The compound 4 was also tested as catalyst in the Baeyer-Villiger oxidation of cyclohexanone by m-chloroperoxybenzoic acid: maximum yields of 88 % and 100 % of ϵ-caprolactone were achieved upon conventional heating at 50 °C for 4 h and MW irradiation at 70 or 80 °C during 30 min, respectively. It was also possible to obtain the lactone (up to 16 % yield) directly from the cyclohexane via a tandem oxidation/Baeyer-Villiger oxidation reaction using the same oxidant., (© 2024 Wiley-VCH GmbH.)

Unprecedented iron-based silsesquioxane/acetylacetonate complexes were synthesized. The intriguing cage-like structure of compounds is alkaline metal-dependent: the Fe 2 Li 2 complex includes condensed Si 6 -silsesquioxane and four acetylacetonate ligands; the Fe 4 Na 4 complex exhibits two cyclic Si 4 -silsesquioxane and eight acetylacetonate ligands, while the Fe 3 K 3 complex features two cyclic Si 3 -silsesquioxane and six acetylacetonate ligands. The latter case is the very first observation of small trimeric silsesquioxane ligands in the composition of cage-like metallasilsesquioxanes. The Fe 4 Na 4 -based complex exhibits a record high activity in the oxidation of inert alkanes with peroxides (55% yield of oxygenates in cyclohexane oxidation). It also acts as a catalyst in the cycloaddition of CO 2 with epoxides, leading to cyclic carbonates in good yields (58-96%).

A small family of nonanuclear Cu 5 Cs 4 -based phenylsilsesquioxanes 1 - 2 were prepared by a convenient self-assembly approach and characterized by X-ray diffraction studies. The compounds 1 and 2 show some unprecedented structural features such as the presence of a [Ph 14 Si 14 O 28 ] 14- silsesquioxane ligand and a Cu II 5 Cs I 4 nuclearity in which the metal cations occupy unusual positions within the cluster. Copper ions are "wrapped" into a silsesquioxane matrix, while cesium ions are located in external positions. This resulted in cesium-involved aggregation of coordination polymer structures. Both compounds 1 and 2 realize specific metallocene (cesium-phenyl) linkage between neighboring cages. Compound 2 is evaluated as a catalyst in the Baeyer-Villiger (B-V) oxidation of cyclohexanone and tandem cyclohexane oxidation/B-V oxidation of cyclohexanone with m -chloroperoxybenzoic acid (mCPBA) as an oxidant, in an aqueous acetonitrile medium, and HNO 3 as the promoter. A quantitative yield of ε-caprolactone was achieved under conventional heating at 50 °C for 4 h or MW irradiation for 30 min (for cyclohexanone as substrate); 17 and 19% yields of lactone upon MW irradiation at 80 °C for 30 min and heating at 50 °C for 4 h, respectively (for cyclohexane as a substrate), were achieved. Complex 2 was evaluated as a catalyst for the oxidation of alkanes to alkyl hydroperoxides and alcohols to ketones with peroxides at 60 °C in acetonitrile. The maximum yield of cyclohexane oxidation products was 30%. Complex 2 exhibits high activity in the oxidation of alcohols.

A family of unusual octacopper cage methylsilsesquioxanes 1 - 4 were prepared and characterized. Features of their cagelike (prismatic) structure were established using X-ray diffraction studies. Effects of distortion of prismatic cages 1 - 4 due to variation of (i) additional alkaline metal ions (K, Rb, or Cs), (ii) combination of solvating ligands, and (iii) nature of encapsulating species were found. Opportunities for the design of supramolecular 1D extended structures were found. These opportunities are based on (i) formate linkers between copper centers (in the case of Cu 8 K 2 -based compound 2 ) or (ii) crown ether-like contacts between cesium ions and siloxane cycles (in the case of Cu 8 Cs 2 -based compound 4 ). Cu 8 Cs 2 -complex 4 was evaluated in the catalysis of alkanes and alcohols. Complex 4 exhibits high catalytic activity. The yield of cyclohexane oxidation products is 35%. The presence of nitric acid is necessary as a co-catalyst. The oxidation of alcohols with the participation of complex 4 as a catalyst and tert-butyl hydroperoxide as an oxidizer also proceeds in high yields of up to 98%.

A series of phenylsilsesquioxane-benzoate heptacopper complexes 1 - 3 were synthesized and characterized by X-ray crystallography. Two parallel routes of toluene spontaneous oxidation (into benzyl alcohol and benzoate) assisted the formation of the cagelike structure 1 . A unique multi-ligation of copper ions (from ( i ) silsesquioxane, ( ii ) benzoate, ( iii ) benzyl alcohol, ( iv ) pyridine, ( v ) dimethyl-formamide and ( vi ) water ligands) was found in 1 . Directed self-assembly using benzoic acid as a reactant afforded complexes 2 - 3 with the same main structural features as for 1 , namely heptanuclear core coordinated by ( i ) two distorted pentameric cyclic silsesquioxane and ( ii ) four benzoate ligands, but featuring other solvate surroundings. Complex 3 was evaluated as a catalyst for the oxidation of alkanes to alkyl hydroperoxides and alcohols to ketones with hydrogen peroxide and tert-butyl hydroperoxide, respectively, at 50 °C in acetonitrile. The maximum yield of cyclohexane oxidation products as high as 32% was attained. The oxidation reaction results in a mixture of cyclohexyl hydroperoxide, cyclohexanol, and cyclohexanone. Upon the addition of triphenylphosphine, the cyclohexyl hydroperoxide is completely converted to cyclohexanol. The specific regio- and chemoselectivity in the oxidation of n -heptane and methylcyclohexane, respectively, indicate the involvement of of hydroxyl radicals. Complex 3 exhibits a high activity in the oxidation of alcohols.

The first examples of metallasilsesquioxane complexes, including ligands of the 8-hydroxyquinoline family 1 - 9 , were synthesized, and their structures were established by single crystal X-ray diffraction using synchrotron radiation. Compounds 1 - 9 tend to form a type of sandwich-like cage of Cu 4 M 2 nuclearity (M = Li, Na, K). Each complex includes two cisoid pentameric silsesquioxane ligands and two 8-hydroxyquinoline ligands. The latter coordinates the copper ions and corresponding alkaline metal ions (via the deprotonated oxygen site). A characteristic (size) of the alkaline metal ion and a variation of characteristics of nitrogen ligands (8-hydroxyquinoline vs. 5-chloro-8-hydroxyquinoline vs. 5,7-dibromo-8-hydroxyquinoline vs. 5,7-diiodo-8-hydroxyquinoline) are highly influential for the formation of the supramolecular structure of the complexes 3a , 5 , and 7 - 9 . The Cu 6 Na 2 -based compound 2 exhibits high catalytic activity towards the oxidation of ( i ) hydrocarbons by H 2 O 2 activated with HNO 3 , and ( ii ) alcohols by tert -butyl hydroperoxide. Studies of kinetics and their selectivity has led us to conclude that it is the hydroxyl radicals that play a crucial role in this process.

The present study describes a new feature in the self-assembly of cagelike copperphenylsilsesquioxanes: the strong influence of acetone solvates on cage structure formation. By this simple approach, a series of novel tetra-, hexa-, or nonacoppersilsesquioxanes were isolated and characterized. In addition, several new complexes of Cu 4 or Cu 6 nuclearity bearing additional nitrogen-based ligands (ethylenediamine, 2,2'-bipyridine, phenanthroline, bathophenanthroline, or neocuproine) were produced. Single-crystal X-ray diffraction studies established molecular architectures of all of the synthesized products. Several coppersilsesquioxanes represent a novel feature of cagelike metallasilsesquioxane (CLMS) in terms of molecular topology. A Cu 4 -silsesquioxane complex with ethylenediamine (En) ligands was isolated via the unprecedented self-assembly of a partly condensed framework of silsesquioxane ligands, followed by the formation of a sandwich-like cage. Two prismatic Cu 6 complexes represent the different conformers─regular and elliptical hexagonal prisms, "cylinders", determined by the different orientations of the coordinated acetone ligands (" shape-switch effect"). A heterometallic Cu 4 Na 4 -sandwich-like derivative represents the first example of a metallasilsesquioxane complex with diacetone alcohol ligands formed in situ due to acetone condensation reaction. As a selected example, the compound [(Ph 6 Si 6 O 11 ) 2 Cu 4 En 2 ]·(acetone) 2 was explored in homogeneous oxidation catalysis. It catalyzes the oxidation of alkanes to alkyl hydroperoxides with hydrogen peroxide and the oxidation of alcohols to ketones with tert -butyl hydroperoxide. Radical species take part in the oxidation of alkanes. Besides, [(Ph 6 Si 6 O 11 ) 2 Cu 4 En 2 ]·(acetone) 2 catalyzes the mild oxidative functionalization of gaseous alkanes (ethane, propane, n -butane, and i -butane). Two different model reactions were investigated: (1) the oxidation of gaseous alkanes with hydrogen peroxide to give a mixture of oxygenates (alcohols, ketones, or aldehydes) and (2) the carboxylation of C n gaseous alkanes with carbon monoxide, water, and potassium peroxodisulfate to give C n +1 carboxylic acids (main products), along with the corresponding C n oxygenates. For these reactions, the effects of acid promoter, reaction time, and substrate scope were explored. As expected for free-radical-type reactions, the alkane reactivity follows the trend C 2 H 6 < C 3 H 8 < n -C 4 H 10 < i -C 4 H 10 . The highest total product yields were observed in the carboxylation of i -butane (up to 61% based on i -C 4 H 10 ). The product yields and catalyst turnover numbers (TONs) are remarkable, given an inertness of gaseous alkanes and very mild reaction conditions applied (low pressures, 50-60 °C temperatures).

The reactions of CuX 2 (X = Cl, Br) with dipinodiazafluorenes yielded four new complexes [CuX 2 L 1 ] 2 (X = Cl ( 1 ), Br ( 2 ), L 1 = (1R,3R,8R,10R)-2,2,9,9-Tetramethyl-3,4,7,8,9,10-hexahydro-1H-1,3:8,10-dimethanocyclopenta [1,2-b:5,4-b']diquinolin-12(2H)-one) and [(CuX 2 ) 2 L 2 ]n (X = Cl ( 3 ), Br ( 4 ), L 2 = (1R,3R,8R,10R,1'R,3'R,8'R,10'R)-2,2,2',2',9,9,9',9'-Octamethyl-1,1',2,2',3,3',4,4',7,7',8,8',9,9',10,10'-hexadecahydro-1,3:1',3':8,10:8',10'-tetramethano-12,12'-bi(cyclopenta [1,2-b:5,4-b']diquinolinylidene). The complexes were characterized by IR and EPR spectroscopy, HR-ESI-MS and elemental analysis. The crystal structures of compounds 1 , 2 and 4 were determined by X-ray diffraction (XRD) analysis. Complexes 1 - 2 have a monomeric structure, while complex 4 has a polymeric structure due to additional coordinating N,N sites in L 2 . All complexes contain a binuclear fragment {Cu 2 (μ-X) 2×2 } (X = Cl, Br) in their structures. Each copper atom has a distorted square-pyramidal coordination environment formed by two nitrogen atoms and three halogen atoms. The Cu-N ax distance is elongated compared to Cu-N eq . The EPR spectra of compounds 1 - 4 in CH 3 CN confirm their paramagnetic nature due to the d 9 electronic configuration of the copper(II) ion. The magnetic properties of all compounds were studied by the method of static magnetic susceptibility. For complexes 1 and 2 , the effective magnetic moments are µ eff ≈ 1.87 and 1.83 µ B (per each Cu 2+ ion), respectively, in the temperature range 50-300 K, which are close to the theoretical spin value (1.73 µ B ). Ferromagnetic exchange interactions between Cu(II) ions inside {Cu 2 (μ-X) 2 X 2 } (X = Cl, Br) dimers ( J / k B ≈ 25 and 31 K for 1 and 2 , respectively) or between dimers ( θ ' ≈ 0.30 and 0.47 K for 1 and 2 , respectively) were found at low temperatures. For compounds 3 and 4 , the magnetic susceptibility is well described by the Curie-Weiss law in the temperature range 1.77-300 K with µ eff ≈ 1.72 and 1.70 µ B for 3 and 4 , respectively, and weak antiferromagnetic interactions (θ ≈ -0.4 K for 3 and -0.65 K for 4 ). Complexes 1 - 4 exhibit high catalytic activity in the oxidation of alkanes and alcohols with peroxides. The maximum yield of cyclohexane oxidation products reached 50% (complex 3 ). Based on the data on the study of regio- and bond-selectivity, it was concluded that hydroxyl radicals play a decisive role in the oxidation reaction. The initial products in reactions with alkanes are alkyl hydroperoxides.

Methyl-substituted 8-hydroxyquinolines (Hquin) were successfully used to synthetize five-coordinated oxovanadium(IV) complexes: [VO(2,6-(Me) 2 -quin) 2 ] ( 1 ), [VO(2,5-(Me) 2 -quin) 2 ] ( 2 ) and [VO(2-Me-quin) 2 ] ( 3 ). Complexes 1 - 3 demonstrated high catalytic activity in the oxidation of hydrocarbons with H 2 O 2 in acetonitrile at 50 °C, in the presence of 2-pyrazinecarboxylic acid (PCA) as a cocatalyst. The maximum yield of cyclohexane oxidation products attained was 48%, which is high in the case of the oxidation of saturated hydrocarbons. The reaction leads to the formation of a mixture of cyclohexyl hydroperoxide, cyclohexanol and cyclohexanone. When triphenylphosphine is added, cyclohexyl hydroperoxide is completely converted to cyclohexanol. Consideration of the regio- and bond-selectivity in the oxidation of n-heptane and methylcyclohexane, respectively, indicates that the oxidation proceeds with the participation of free hydroxyl radicals. The complexes show moderate activity in the oxidation of alcohols. Complexes 1 and 2 reduce the viability of colorectal (HCT116) and ovarian (A2780) carcinoma cell lines and of normal dermal fibroblasts without showing a specific selectivity for cancer cell lines. Complex 3 on the other hand, shows a higher cytotoxicity in a colorectal carcinoma cell line (HCT116), a lower cytotoxicity towards normal dermal fibroblasts and no effect in an ovarian carcinoma cell line (order of magnitude HCT116 > fibroblasts > A2780).

A new monoiminoacenaphthenone 3,5-(CF 3 ) 2 C 6 H 3 -mian (complex 2 ) was synthesized and further exploited, along with the already known monoiminoacenaphthenone dpp-mian, to obtain oxidovanadium(IV) complexes [VOCl 2 (dpp-mian)(CH 3 CN)] ( 3 ) and [VOCl(3,5-(CF 3 ) 2 C 6 H 3 -bian)(H 2 O)][VOCl 3 (3,5-(CF 3 ) 2 C 6 H 3 -bian)]·2.85DME ( 4 ) from [VOCl 2 (CH 3 CN) 2 (H 2 O)] ( 1 ) or [VCl 3 (THF) 3 ]. The structure of all compounds was determined using X-ray structural analysis. The vanadium atom in these structures has an octahedral coordination environment. Complex 4 has an unexpected structure. Firstly, it contains 3,5-(CF 3 ) 2 C 6 H 3 -bian instead of 3,5-(CF 3 ) 2 C 6 H 3 -mian. Secondly, it has a binuclear structure, in contrast to 3 , in which two oxovanadium parts are linked to each other through V=O···V interaction. This interaction is non-covalent in origin, according to DFT calculations. In structures 2 and 3 , non-covalent π-π staking interactions between acenaphthene moieties of the neighboring molecules (distances are 3.36-3.40 Å) with an estimated energy of 3 kcal/mol were also found. The redox properties of the obtained compounds were studied using cyclic voltammetry in solution. In all cases, the reduction processes initiated by the redox-active nature of the mian or bian ligand were identified. The paramagnetic nature of complexes 3 and 4 has been proven by EPR spectroscopy. Complexes 3 and 4 exhibited high catalytic activity in the oxidation of alkanes and alcohols with peroxides. The yields of products of cyclohexane oxidation were 43% (complex 3 ) and 27% (complex 4 ). Based on the data regarding the study of regio- and bond-selectivity, it was concluded that hydroxyl radicals play the most crucial role in the reaction. The initial products in the reactions with alkanes are alkyl hydroperoxides, which are easily reduced to their corresponding alcohols by the action of triphenylphosphine (PPh 3 ). According to the DFT calculations, the difference in the catalytic activity of 3 and 4 is most likely associated with a different mechanism for the generation of ● OH radicals. For complex 4 with electron-withdrawing CF 3 substituents at the diimine ligand, an alternative mechanism, different from Fenton's and involving a redox-active ligand, is assumed.

The rate of hydrolysis-condensation reaction of phenyltrichlorosilane in water-acetone solutions and the product yields were shown to significantly depend on the concentration of HCl (C HCl ) in the solutions. The main product of the reaction was all- cis- (tetrahydroxy)(tetraphenyl)cyclotetrasiloxane. This was different from the earlier published results of analogous reactions of m -tolylSiCl 3 , m -ClPhSiCl 3 , and α -naphtylSiCl, in which some products of other types were formed. For example, trans -1,1,3,3-tetrahydroxy-1,3-di- α -naphtyldisiloxane was obtained in the case of α -naphtylSiCl 3 . All- cis- (tetrahydroxy)(tetraphenyl)cyclotetrasiloxane was treated in acetone with HCl to give the other three geometric isomers ( cis-cis-trans -, cis-trans- , and all- trans- ). The thermal self-condensation of these four isomers under "pseudo"-equilibrium conditions (under atmospheric pressure) was investigated in different solvents, in quartz or molybdenum glass flasks. The compositions of the products were monitored by APCI-MS and 29 Si NMR spectroscopy. It was shown that all- cis - and cis-cis-trans -isomers in toluene or anisole mostly gave the cage-like Ph-T 8,10,12,14 and uncompleted cage-like Ph-T 10,12 OSi(HO)Ph compounds. In contrast to these two isomers, the cis-trans -isomer in toluene mainly formed dimers with the loss of one or two molecules of water. However, in acetonitrile, significant amounts of Ph-T 10,12 and Ph-T 10,12 OSi(HO)Ph species were formed along with the dimers. All- trans -isomer did not enter into the reaction at all.

The hydrolysis-condensation reactions of m -tolyl, m -chlorophenyl, and α -naphtyl-trichlorsilanes, ( 1 , 2 , and 3 , respectively) in water-acetone solutions were examined for how they were influenced by the change in the concentration of HCl (C HCl ). The composition of the products was monitored by 29 Si NMR spectroscopy and atmospheric pressure chemical ionization mass spectrometry (APCI-MS). The acidity of the medium was shown to affect the yields of the products, and so, what products were formed. For 3 , e.g., APCI-MS showed peaks of α -naphtyl-T 8 and α -naphtyl-T 10 as the most abundant in the spectra taken after 48 and 240 h for the reaction conducted at C HCl = 0.037 mol L -1 . Unlike this, at C HCl = 0.15 mol L -1 , those peaks were of [ α -naphtyl(HO) 2 SiO] 2 ( α -naphtyl)(HO)Si and/or [ α -naphtyl(HO)Si] 3 , [ α -naphtyl(HO)Si] 4,5 , and α -naphtyl-T 8 after 192 h. However, at both C HCl values, the main product (and an intermediate) after 24 h was trans -1,1,3,3-tetrahydroxy-1,3-di- α -naphtyldisiloxane. It was isolated and its structure established by 1 H-, 29 Si-NMR, and X-ray powder diffraction.

A new "bicycle helmet"-like copper(ii),sodiumphenylsilsesquioxane Ph12Si12O12(OH)(O-)11Cu5Na(bipy)3(H2O) exhibited high catalytic efficiency in two homogeneous reactions: (i) functionalization of C-H compounds; (ii) formation of benzamides from alcohols.

Oligo- and polycyclosiloxanes were obtained by the polycondensation of (tetrahydroxy)(tetraaryl)cyclotetrasiloxanes in equilibrium and non-equilibrium conditions in the presence and absence of montmorillonite (MMT). Their composition and the structures of their components were investigated by infrared (IR) spectroscopy, 29 Si nuclear magnetic resonance (NMR) spectroscopy, atmospheric pressure chemical ionization (APCI) mass spectrometry, powder X-ray diffraction (XRD), and gel-penetrating chromatography (GPC). Also, a comparison of polymers formed in the presence of MMT and via anionic polymerization was performed showing differences in their structures., Competing Interests: The authors declare no conflict of interest.

The synthesis, composition, and catalytic properties of a new family of hexanuclear Cu(II)-based phenylsilsesquioxanes are described here. Structural studies of 17 synthesized compounds revealed the general principle underlying their molecular topology: viz., a central metal oxide layer consisting of two Cu 3 trimers is coordinated by two cyclic [PhSiO 1.5 ] 5 siloxanolate ligands to form a skewed sandwich architecture with the composition [(PhSiO 1.5 ) 10 (CuO) 6 ] 2+ . In addition to this O ligation by the siloxanolate rings, two opposite copper ions are additionally coordinated by the nitrogen atoms of corresponding N ligand(s), such as 2,2'-bipyridine (compounds 1-9), 1,10-phenanthroline (compounds 10-13), mixed 1,10-phenanthroline/2,2'-bipyridine (compound 14), or bathophenanthroline (compounds 15-17). Finally, the charge balance is maintained by two HO - (compounds 1-7, 10-13, and 15-17), two H 3 CO - (compound 8), or two CH 3 COO - (compounds 9 and 14) anions. Complexes 1 and 10 exhibited a high activity in the oxidative amidation oxidation of alcohols. Compounds 1, 10, and 15 are very efficient homogeneous catalysts in the oxidation of alkanes and alcohols with peroxides.

Six new copper(ii) complexes with 2,2':6',2''-terpyridine (4'-R n -terpy) [1 (R 1 = furan-2-yl), 2 (R 2 = thiophen-2-yl), and 3 (R 3 = 1-methyl-1H-pyrrol-2-yl)] and 2,6-di(thiazol-2-yl)pyridine derivatives (R n -dtpy) [4 (R 1 ), 5 (R 2 ), and 6 (R 3 )] have been synthesized by a reaction between copper(ii) chloride and the corresponding ligand. The complexes have been characterized by UV-vis and IR spectroscopy, and their structures have been determined by X-ray analysis. The antiproliferative potential of copper(ii) complexes of 2,2':6',2''-terpyridine and 2,6-di(thiazol-2-yl)pyridine derivatives towards human colorectal (HCT116) and ovarian (A2780) carcinoma as well as towards lung (A549) and breast adenocarcinoma (MCF7) cell lines was examined. Complex 1 and complex 6 were found to have the highest antiproliferative effect on A2780 ovarian carcinoma cells, particularly when compared with complex 2, 3 with no antiproliferative effect. The order of cytotoxicity in this cell line is 6 > 1 > 5 > 4 > 2 ≈ 3. Complex 2 seems to be much more specific towards colorectal carcinoma HCT116 and lung adenocarcinoma A549 cells. The viability loss induced by the complexes agrees with Hoechst 33258 staining and typical morphological apoptotic characteristics like chromatin condensation and nuclear fragmentation. The specificity towards different types of cell lines and the low cytotoxic activity towards healthy cells are of particular interest and are a positive feature for further developments. Complexes 1-6 were also tested in the oxidation of alkanes and alcohols with hydrogen peroxide and tert-butyl-hydroperoxide (TBHP). The most active catalyst 4 gave, after 120 min, 0.105 M of cyclohexanol + cyclohexanone after reduction with PPh 3 . This concentration corresponds to a yield of 23% and TON = 210. Oxidation of cis-1,2-dimethylcyclohexane with m-CPBA catalyzed by 4 in the presence of HNO 3 gave a product of a stereoselective reaction (trans/cis = 0.47). Oxidation of secondary alcohols afforded the target ketones in yields up to 98% and TON = 630.

A series of four unprecedented heterometallic metallagermsesquioxanes were synthesized. Their cage-like architectures have a unique type of molecular topology consisting of the hexairon oxo {Fe 6 O 19 } core surrounded in a triangular manner by three cyclic germoxanolates [PhGe(O)O] 5 . This structural organization induces antiferromagnetic interactions between the Fe III ions through the oxygen atoms. Evaluated for this first time in catalysis, these compounds showed a high catalytic activity in the oxidation of alkanes and the oxidative formation of benzamides from alcohols., (© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Cobalt pi-complexes, previously described in the literature and specially synthesized and characterized in this work, were used as catalysts in homogeneous oxidation of organic compounds with peroxides. These complexes contain pi-butadienyl and pi-cyclopentadienyl ligands: [(tetramethylcyclobutadiene)(benzene)cobalt] hexafluorophosphate, [(C₄Me₄)Co(C₆H₆)]PF₆ ( 1 ); diiodo(carbonyl)(pentamethylcyclopentadienyl)cobalt, Cp*Co(CO)I₂ ( 2 ); diiodo(carbonyl)(cyclopentadienyl)cobalt, CpCo(CO)I₂ ( 3 ); (tetramethylcyclobutadiene)(dicarbonyl)(iodo)cobalt, (C₄Me₄)Co(CO)₂I ( 4 ); [(tetramethylcyclobutadiene)(acetonitrile)(2,2'-bipyridyl)cobalt] hexafluorophosphate, [(C₄Me₄)Co(bipy)(MeCN)]PF₆ ( 5 ); bis[dicarbonyl(B-cyclohexylborole)]cobalt, [(C₄H₄BCy)Co(CO)₂]₂ ( 6 ); [(pentamethylcyclopentadienyl)(iodo)(1,10-phenanthroline)cobalt] hexafluorophosphate, [Cp*Co(phen)I]PF₆ ( 7 ); diiodo(cyclopentadienyl)cobalt, [CpCoI₂]₂ ( 8 ); [(cyclopentadienyl)(iodo)(2,2'-bipyridyl)cobalt] hexafluorophosphate, [CpCo(bipy)I]PF₆ ( 9 ); and [(pentamethylcyclopentadienyl)(iodo)(2,2'-bipyridyl)cobalt] hexafluorophosphate, [Cp*Co(bipy)I]PF₆ ( 10 ). Complexes 1 and 2 catalyze very efficient and stereoselective oxygenation of tertiary C-H bonds in isomeric dimethylcyclohexanes with MCBA: cyclohexanols are produced in 39 and 53% yields and with the trans / cis ratio (of isomers with mutual trans - or cis -configuration of two methyl groups) 0.05 and 0.06, respectively. Addition of nitric acid as co-catalyst dramatically enhances both the yield of oxygenates and stereoselectivity parameter. In contrast to compounds 1 and 2 , complexes 9 and 10 turned out to be very poor catalysts (the yields of oxygenates in the reaction with cis -1,2-dimethylcyclohexane were only 5%-7% and trans / cis ratio 0.8 indicated that the oxidation is not stereoselective). The chromatograms of the reaction mixture obtained before and after reduction with PPh₃ are very similar, which testifies that alkyl hydroperoxides are not formed in this oxidation. It can be thus concluded that the interaction of the alkanes with MCPBA occurs without the formation of free radicals. The complexes catalyze oxidation of alcohols with tert -butylhydroperoxide (TBHP). For example, tert -BuOOH efficiently oxidizes 1-phenylethanol to acetophenone in 98% yield if compound 1 is used as a catalyst.

A new pentanuclear "cylinder"-like cobalt(ii) phenylsilsesquioxane [(PhSiO1.5)10(CoO)5(NaOH)] exhibits a slow relaxation of the magnetization and a high catalytic activity and stereoselectivity in the oxidation of alkanes and alcohols.

The reactions of mer-[Re(p-NTol)X3(PPh3)2] (X = Cl, Br) with chelating phenolate-based ligands (2-(2-hydroxy-5-methylphenyl)benzotriazole (HL(1)), 2-(2-hydroxyphenyl)benzothiazole (HL(2)) or 2-(2-hydroxyphenyl)benzoxazole (HL(3))) afforded a series of p-tolylimido rhenium(v) complexes cis- or trans-(X,X)-[Re(p-NTol)X2(L)(PPh3)]·yMeCN (where X = Cl, Br; L = L(1), L(2), L(3) and y = 0-2) and [Re(p-NTol)X(L)(PPh3)2]Z·pPPh3 (where X = Cl, Br; Z = ReO4, PF6; L = L(1), L(2), L(3) and p = 0 or 1). The reported compounds were characterized by elemental analysis, FT-IR, NMR ((1)H, (13)C and (31)P) and X-ray crystallography. Interestingly, the halide ions of [Re(p-NTol)Cl2(L(1))(PPh3)]·MeCN (1) and [Re(p-NTol)Cl2(L(2))(PPh3)]·2MeCN (3) are in cis relative dispositions, whereas the complexes [Re(p-NTol)Br2(L)(PPh3)] (L(1) for 2, L(2) for 4 and L(3) for 6) and [Re(p-NTol)Cl2(L(3))(PPh3)] (5) were found to be trans-(X,X) isomers. The compounds [Re(p-NTol)X(L)(PPh3)2](PF6) (X = Cl, Br; L = L(1) and L(2)) and [Re(p-NTol)X(L(3))(PPh3)2](PF6)·PPh3 (X = Cl, Br) have been tested in oxidative catalysis. A few compounds exhibited very good catalytic properties in oxidation of alcohols with tert-BuOOH (TBHP) in acetonitrile solution at moderate temperatures. Complex [Re(p-NTol)Cl(L(2))(PPh3)2]PF6 (13) is the catalyst of choice for oxidation of 1-phenylethanol to acetophenone (in 80% yield; turnover number attained 290 after 30 h) and cyclooctanol to cyclooctanone (in 88% yield). Notably lower activity has been found in the oxidation of alkanes with TBHP. Product distribution in the oxidation of methylcyclohexane indicates some steric hindrance around the reaction center.

A (salen)titanium catalyst has been found to induce the asymmetric addition of potassium cyanide and acetic anhydride to aldehydes, giving enantiomerically enriched cyanohydrin esters with up to 92% enantiomeric excess using just 1 mol% of the catalyst. This is the first report of the asymmetric synthesis of cyanohydrin derivatives using a cyanide source which is non-volatile and inexpensive.

Gas-liquid chromatography was used to estimate content of short-chain fatty acids (SCFA) in 25 patients with cholelithiasis, 32 patients with irritable colon syndrome and constipation (ICS) and 35 healthy subjects. It was found that SCFA absolute and relative concentration in the feces of cholelithiasis patients is abnormal indicating disturbance of microbiocenosis as shown by changes in functional activity of some anaerobes of the intestinal microflora participating in enterohepatic circulation of bile acids. Alterations of SCFA content in the serum of cholelithiasis patients may be related to steroids disbolism. The study of SCFA in the feces and peripheral blood serum from cholelithiasis patients is of diagnostic value.

A new type of efficient chiral catalyst has been elaborated for asymmetric C-alkylation of CH acids under PTC conditions. Sodium alkoxides formed from chiral derivatives of tartaric acid and aminophenols (TADDOL's 2a-e and NOBIN's 3a-h) can be used as chiral catalysts in the enantioselective alkylation, as exemplified by the reaction of Schiff's bases 1a-e derived from alanine esters and benzaldehydes with active alkyl halides. Acid-catalyzed hydrolysis of the products formed in the reaction afforded (R)-alpha-methylphenylalanine, (R)-alpha-naphthylmethylalanine, and (R)-alpha-allylalanine in 61-93% yields and with ee 69-93%. The procedure could be successfully scaled up to 6 g of substrate 1b. When (S,S)-TADDOL or (R)-NOBIN are used, the (S)-amino acids are formed. A mechanism rationalizing the observed features of the reaction has been suggested.