Ruthenium tetrazene complexes with general formula [Cp*RuCl(1,4-R 2 N 4)] (Cp* = η 5-C 5 Me 5), where R = benzyl (1), 2-fluorobenzyl (2), β-D-glucopyr anosyl-unprotected (3a) and acyl-protected (3b-d), 2-acetamido-β-Dglucopyranosyl-unprotected (4a) and acyl-protected (4b-d), propyl-β-D-glucopyranoside-unprotected (5a), and O-acetylated (5b), were synthesized and characterized using nuclear magnetic resonance and electrospray ionizationmass spectrometry. In addition, the molecular structure of 3b was determined using X-ray crystallography. The cytotoxicity of complexes against ovarian (A2780, SK-OV-3) and breast (MDA-MB-231) cancer cell lines and noncancerous cell line HEK-293 was evaluated and compared to cisplatin activity. The carbohydrate-modified complexes bearing acyl-protecting groups exhibited higher efficacy (in low micromolar range) than unprotected ones, where the most active 4d was superior to cisplatin up to five times against all investigated cancer cell lines; however, no significant selectivity was achieved. The complex induced apoptotic cell death at low micromolar concentrations (0.5 μM for A2780 and HEK293; 2 μM for SK-OV-3 and MDA-MB-231). K E Y W O R D S anticancer activity, glucose derivatives, ruthenium complexes, tetrazene ligands V. Hamala and A. Martišová contributed equally to this study.

The reactivity of variously substituted alkynylsilanes toward selected group 4 metallocene complexes was investigated. Reactions of the alkynylsilanes R(1)C(2)SiR(2)(2)H (R(1) = SiMe(3), R(2) = Me, 1; R(1) = SiMe(3), R(2) = Ph, 2; R(1) = SiMe(2)H, R(2) = Me, 5) with Cp(2)TiMe(2) (Cp = eta(5)-cyclopentadienyl) resulted, upon methyl group transfer to the silyl group, in the previously described titanocene alkyne complexes Cp(2)Ti(R(1)C(2)SiR(2)(2)R(3)) (R(1) = Me(3)Si, R(2) = R(3) = Me, 3; R(1) = HMe(2)Si, R(2) = R(3) = Me, 6) or the unreported complex 4 (R(1) = Me(3)Si, R(2) = Ph, R(3) = Me). The Cp(2)TiCl(2)/n-BuLi system yielded alkyne complexes 6 and 7 (R(1) = HMe(2)Si, R(2) = Me, R(3) = H); no alkyl group transfer was detected. On the other hand, reactions utilizing the Cp(2)ZrCl(2)/n-BuLi system afforded inseparable mixtures; however, complexes of the type Cp(2)Zr[R(1)C(2)SiMe(2)(n-Bu)] (R(1) = Me(3)Si, 8; R(1) = HMe(2)Si, 9) were detected. Cp(2)Hf(n-Bu)(2) reacted with the alkynylsilanes in a diverse way, depending on the substituents of the alkyne substrate. The reaction with an excess of alkyne 1 (R(1) = Me(3)Si, R(2) = Me) afforded only an intractable mixture, which contained Me(3)SiC(2)SiMe(2)(n-Bu) (10). Hafnacyclopentadienes 13-15 as precedented product types were obtained when alkyne 12 (R(1) = Ph, R(2) = Me) was used. In sharp contrast, the symmetrically substituted alkynes 5 (R(1) = HMe(2)Si, R(2) = Me) and H(2)PhSiC(2)SiPhH(2) (18) yielded the hitherto unknown Si-containing metallacycles 16 and 19. A reaction mechanism leading to these products was proposed and subsequently supported by DFT calculations. In addition, the reduction of Cp(2)HfCl(2) with magnesium in THF in the presence of alkynylsilanes was shown to be an alternative route to compounds 14-16 and 19. Presumably due to steric reasons, alkyne 1 could not form any of the product types described above. Nevertheless, it was utilized for the preparation of the PMe(3)-stabilized hafnocene alkyne complex 11.

A series of supported catalysts is prepared by treatment of SBA-15-type mesoporous molecular sieve bearing [triple chemical bond]SiCH(2)CH(2)CH(2)NHCH(2)CH(2)NEt(2) groups with palladium(II) acetate. These catalysts are studied in Suzuki biaryl couplings and in Heck reactions to establish the influence of metal loading and innocent surface modifications (trimethylsilylation). The Suzuki reaction proceeded efficiently with model and practically relevant substrates; the catalyst performance increasing with an increasing degree of metalation (decreasing N/Pd ratio). Catalyst poisoning tests revealed that the reaction takes place in the liquid phase with the catalyst serving as a reservoir of active metal species and also as a stabilizing support once the reaction is performed. In the Heck reactions, on the other hand, the catalyst performance strongly changed with the reaction temperature and with the N/Pd ratio. The material with the lowest metal loading (0.01 mmol palladium per gram of material, N/Pd ratio ca. 100:1) proved particularly attractive in the Heck coupling, being highly active at elevated temperatures, recyclable, and capable of acting as a bifunctional catalyst (i.e., functioning without any external base.

Cationic group 4 metallocene complexes with pendant imine and pyridine donor groups were prepared as stable crystalline [B­(C6F5)4]− salts either by protonation of the intramolecularly bound ketimide moiety in neutral complexes [(η5-C5Me5)­{η5-C5H4CMe2CMe2C­(R)N-κN}­MCl] (M = Ti, Zr, Hf; R = t-Bu, Ph) by PhNMe2H+[B­(C6F5)4]− to give [(η5-C5Me5)­{η5-C5H4CMe2CMe2C­(R)NH-κN}­MCl]+[B­(C6F5)4]− or by chloride ligand abstraction from the complexes [(η5-C5Me5)­(η5-C5H4CMe2CH2C5H4N)­MCl2] (M = Ti, Zr) by Li­[B­(C6F5)4]·2.5Et2O to give [(η5-C5Me5)­(η5-C5H4CMe2CH2C5H4N-κN)­MCl]+[B­(C6F5)4]−. Solid state structures of the new compounds were established by X-ray diffraction analysis, and their electrochemical behavior was studied by cyclic voltammetry. The cationic complexes of Zr and Hf, compared to the corresponding neutral species, exhibited significantly enhanced luminescence predominantly from triplet ligand-to-metal (3LMCT) excited states with lifetimes up to 62 μs and quantum yields up to 58% in the solid state. DFT calculations were performed to explain the structural features and optical and electrochemical properties of the complexes.

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Neutral[Pd(κP,κO-P~O)(κ 3 C,C,C-carbocycloenyl)] complexes, where P~O is a chiral or achiral chelating phosphanylferrocenecarboxylate ligand, were synthesized and characterized by multinuclear NMR spectroscopy. The crystal structure of a representative complex was determined by single-crystal X-ray diffraction analysis. In all complexes, the palladium(II) ion is located at the centre of a square plane formed by the P and O donor atoms from an anionic P~O -ligand, a σ-carbon atom and a C-C double bond from a carbocycloenyl ligand. Neutral methyl complexes with the formulas [PdCl(Me)(κP,κH-P~OH)] and [Pd(Me)(OTs)(κP,κH-P~OH)] were also synthesized and characterized. On the basis of IR, NMR and MS-FAB data, the methyl complexes are proposed to be formulated with the fourth coordination position occupied by an agostic O-H···Pd interaction from a free carboxylic acid moiety [P~OH = 1Ј-(diphenylphosphanyl)ferrocenecarboxylic acid] or a solvent molecule. Selected complexes were employed as catalyst precursors for CO-ethyl-

This material has been used as a photo catalyst for water splitting since 1972 when Fujishima and Honda reported its ability to generate hydrogen and oxygen from water molecules. [1] Titanium dioxide is normally used in advanced oxidation processes, [2] in systems capable of elimi nating a wide variety of chemicals in air and water, as well as solar fuel production (such as H 2 ). [3,4] The photoactivated pro cesses of titanium dioxidebased photo catalysts are achieved when the irradiation energy is higher than its band gap. This generates electrons in the conduction band and holes in valence band, which rapidly migrate to the TiO 2 surface and provoke the generation of extremely reactive spe cies. For example, H 2 O 2 and the radicals OH • , O 2-• formed after the electron and the holes reach the external surface of titanium dioxide, are very important for the photodecomposition of organic pol lutants to CO 2 and H 2 O, which is true for the most active titanium dioxidebased materials. [5,6] The band gap value has a direct impact on the rate of electronhole (e --h +) recombination during the photocatalytic processes. In the case of titanium dioxide, the relatively large band gap, means there is a slow recombination rate compared to most of the other photocatalysts. [7] Three main phases are present in TiO 2 : 1) Anatase (tetrag onal, a = b = 3.785 Å, c = 9.54 Å), 2) brookite (orthorhombic, a = 5.143 Å, b = 5.456 Å, c = 9.182 Å), and 3) rutile (tetragonal a = b = 4.593 Å, c = 2.959 Å). [8,9] The thermodynamically meta stable phases, anatase, and brookite, irrevocably pass into the stable phase of rutile at high temperatures. [7] Each of these phases show its own morphological characteristics and band gap value: In the case of anatase the band gap is of 3.2 eV, while rutile and brookite have band gaps of 3.0 and 3.3 eV, respec tively. In general, anatase shows the most attractive photocata lytic behavior due to its versatility and textural properties. [10][11][12] However, the anatase phase, due to its band gap, can only be activated by UV light, which accounts for approximately only 4% of the solar spectrum. Thus, in order to stabilize the anatase phase at elevated temperatures, and to utilize UV and visible light for photocatalysis, chemical modifiers and dopants are generally employed for the modification of the photocatalytic Titanium dioxide nanomaterials with improved catalytic and photo catalytic properties through codoping with copper and fluorine are synthesized and contain optimal textural and compositional properties, which are not possible without doping or with a single doping of Cu or F separately. The codoped systems promote the generation of a synergistic effect increasing activity of the systems in photocatalytic processes of both potential environmental or energy interest. The photocatalysts show very effective degradations of industrial and emerging contaminants such as ciprofloxacin (80% degradation) and naproxen (72% degradation) using UV light (300 W) in short periods of up to 15 min. An ad...

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