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A study of the oxidation of nitrite in aqueous solution and in H2O/CH3CN is conducted by a cationic trans-dioxoruthenium(VI) complex, trans-[[[Ru.sup.VI](L)(O)2].sup.2} (L= 1,12-dimethyl-3,4,9,10-dibenzo-1,12-diaza-5,8-dioxacyclopentadecane). The coordinated macrocyclic ligand L is resistant to oxidative degradation and ligand exchange.

The oxidation of a series of H(sub 2)Q-X compounds by trans-[Ru(super VI)(tmc)(O)(sub 2)](super 2+) in aqueous solutions and in CH(sub 3)CN, and by trans-[Ru(super IV) (tmc)(O)(CH(sub 3)CN)](super 2+) in CH(Sub 3)CN, occurs by initial, rate-limiting H-atom abstraction. The Marcus cross relation appears to hold well for these H-atom transfer reactions.

Here, we report the use of an amphiphilic Pt(II) complex, K[Pt{(O3SCH2CH2CH2)2bzimpy}Cl] (PtB), as a model to elucidate the key role of Pt···Pt interactions in directing self-assembly by combining temperature-dependent ultraviolet-visible (UV-Vis) spectroscopy, stopped-flow kinetic experiments, quantum mechanics (QM) calculations, and molecular dynamics (MD) simulations. Interestingly, we found that the self-assembly mechanism of PtB in aqueous solution follows a nucleation-free isodesmic model, as revealed by the temperature-dependent UV-Vis experiments. In contrast, a cooperative growth is found for the self-assembly of PtB in acetone–water (7:1, vol/vol) solution, which is further verified by the stopped-flow experiments, which clearly indicates the existence of a nucleation phase in the acetone–water (7:1, vol/vol) solution. To reveal the underlying reasons and driving forces for these self-assembly processes, we performed QM calculations and show that the Pt···Pt interactions arising from the interaction between the pz and dz² orbitals play a crucial role in determining the formation of ordered self-assembled structures. In subsequent oligomer MD simulations, we demonstrate that this directional Pt···Pt interaction can indeed facilitate the formation of linear structures packed in a helix-like fashion. Our results suggest that the self-assembly of PtB in acetone–water (7:1, vol/vol) solution is predominantly driven by the directional noncovalent Pt···Pt interaction, leading to the cooperative growth and the formation of fibrous nanostructures. On the contrary, the self-assembly in aqueous solution forms spherical nanostructures of PtB, which is primarily due to the predominant contribution from the less directional hydrophobic interactions over the directional Pt···Pt and π−π interactions that result in an isodesmic growth. [ABSTRACT FROM AUTHOR]

Research has been conducted on the pig purple acid phosphatase (uteroferrin). The involvement of Fe (super)II, Mn (super)II and Zn (super)II in naturally occutting forms of these phosphatases has been investigated and the details are reported.

Research is presented describing the use of oligopeptides to discover the radical cations of its molecules.

Research has been conducted on the osmium(VI) nitrido complexes that contain Schiff base ligands. The results of their synthesis in the presence of 2,6-dimethylpyridine are described.

The article explains the synthesis and the characterization of trans-[[[Os.sup.III](salen)[(CN).sub.2]].sup.-]. The complex is shown to be widely used as a new paramagnetic building block for the construction of molecule-based magnetic materials.

The oxidation of alkanes by various peroxides is efficiently catalyzed by [[[Os.sup.VI](N)[Cl.sub.4]].sup.-]/Lewis acid in C[H.sub.2][Cl.sub.2]/C[H.sub.3]C[O.sub.2]H to give alcohols and ketones. The new mechanism has involved initial O-atom transfer from ROOH to [[[Os.sup.VI](N)[Cl.sub.4]].sup.-]/Lewis acid to generate [[[Os.sup.VIII](N)(O)[Cl.sub.4]].sup.-]/Lewis acid, which has oxidized alkanes via H-atom abstraction.

A study was conducted to examine the kinetics and mechanisms of the oxidation iodide and bromide anion by trans-[[[Ru.sup.VI]([N.sub.2][O.sub.2])[(O).sub.2]].sup.2+] in aqueous solutions. The mechanism was observed to involve initial oxygen atom transfer from trans-[[[Ru.sup.VI]([N.sub.2][O.sub.2])[(O).sub.2]].sup.2+] to bromide to give trans-[[[Ru.sup.IV]([N.sub.2][O.sub.2])(O)(OBr)].sup.+] followed by parallel aquation and oxidation of bromide and both reactions are acid-catalyzed.

The article presents a new approach, which utilizes the N...N coupling of different (salen)ruthenium(VI) nitrides for the general synthesis of the (salen)ruthenium(III) complexes. These ruthenium salen complexes are shown to be widely used as the catalysts in different organic transformations.

The kinetics of the oxidation of trans-[[[Ru.sup.IV](tmc)(O)(solv)].sup.2+] to trans-[[[Ru.sup.VI](tmc)[(O).sub.2]].sup.2+] (tmc = 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane, a tetradentate macrocyclic tertiary amine ligand, solv = [H.sub.2]O or C[H.sub.3]CN) by Mn[O.sub.4.sup.-] is analyzed in aqueous solutions and in acetonitrile. Large deuterium and oxygen isotope effects are seen for reactions in water.

The design and synthesis of a novel tridentate C,N,[N.sub.pyrazolyl] cyclometalating ligand, 2-phenyl-6-(1H-pyrazol-3-yl)-pyridine (HL) is described. The pH dependence of luminescent properties of this system is attributed to the protonation/deprotonation of the 1-pyrazolyl-NH on the C,N,[N.sub.pyrazolyl] cyclometalated Pt(II) system.

(Salen)manganese (V) nitro species are activated by electrophiles such as trifluoroacetic anhydride (TFAA) or trifluoroacetic acid (TFA) to produce [N.sub.2]. Mechanistic studies suggest that the manganese(V) nitrido species first react with TFAA or TFA to produce an imido species, which then undergoes N...N coupling.

The kinetics and mechanistic study of the BF3-activated oxidation of alkanes and arylalkanes by KMnO4 are reported. The results have demonstrated that BF3 forms an adduct with MnO(sub 4)(super -) in CH3CN that oxidizes hydrocarbons at rates over 7 orders of magnitude faster than that by MnO(sub 4)(super -) alone.

The synthesis, structures, and magnetic properties of four cyano-bridged M(super II)Ru(super III)(sub 2) compounds prepared from the paramagnetic Ru(super III) building blocks, trans-[Ru(salen)(CN)2](super -) and trans-[Ru(acac)2(CN)2](super -) are described. The use of trans-[Ru(acac)2(CN)2](super -) and trans-[Ru(salen)-(CN)2](super -) as building blocks has produced a number of trinuclear, 2-D, and 3-D M(super II)Ru2(super III) compounds.

The synthesis and reactivities of a highly electrophillic, cationic ruthenium(VI) nitrido complex containing the cyclohexylene-bridged salen ligand, N,N'-bis(salicylidene) omicron-cyclohexyldiamine dianion is reported. The result indicates that the steric and electronic tunabality of slaen would be utilized to probe the mechanism of the aziridination reaction and reduction of Ru(sub IV) (AZ(-H) to RuIII(AZ).

A study of remarkable activating effects of FeCl3 on the oxidation of alkanes by the nitridoosmate(VIII) ion, [Os(N)(O)3](super -), is reported. Findings show that methane monooxygenase (MMO), which catalyzes the oxidation of methane to methanol by dioxygen, is believed to involve a bis(mu-oxo)-diiron(IV) species as the active oxidant.

Research has been conducted on alkylaromatic compounds. The study of the oxidation of these compounds in CH (sub)3 CN by trans-dioxoruthenium(VI) complex is presented.

Research has been conducted on three-dimensional malonate bridged networks. The authors describe the synthesis of these networks in H (sub)2 O -N,N-dimethylformamide solution.

Results suggest that oxidation of the phenolic compounds in water and acetonitrile by a cationic trans-dioxoruthenium(VI) complex occurs mostly through a hydrogen atom abstraction mechanism although an alternative mechanism is plausible. Data show that the correlation between rate constant and bond dissociation enthalpies is more consistent with the former mechanism.

The catalytic activities of the ruthenium(II) complex cis-[Ru(6,6-Cl2bpy)2(OH2)2](CF3SO3)2 (1) in organic oxidations using tert-butyl hydroperoxide (TBHP) as terminal oxidant are presented. Mechanistic studies showing a large primary kinetic isotope effect suggest a hydrogen-atom abstraction pathway for these oxidations. Data from these studies reveal that oxidations of saturated hydrocarbons by complex 2, the '1+TBHP' protocol and Gif-type systems are not similar from a mechanistic viewpoint.

Using the native mussel Unio crassus and artificial mussels (AMs), profiles of 11 metals (Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, U, Zn) were determined and compared in winter and summer along a pollution gradient in Sarıçay Stream, Turkey. Principal components analysis and correlation analysis showed that metal profiles in the native mussels and AMs were different. Concentrations of most metals were significantly higher in the native mussels compared with AMs, suggesting that metals in Sarıçay Stream predominantly existed in suspended particulates and food compartments, rather than in dissolved form. Although U was not readily accumulated by the native mussels, it could be taken up by AMs. Overall, the results suggest that the use of native mussels and AMs in water quality monitoring can provide complementary information and a better estimate and coverage of different metal species and forms in aquatic environments. [ABSTRACT FROM AUTHOR]

The research shows that the nucleophilic addition to salophen and salen coordinated to a high-valent metal center could be very facile. The reason for the low turnovers of most (salen)-mangnese epoxidation catalysts could be due to attack at the (salen) manganese (V) oxo intermediates by nucleophiles in the reaction mixture, hence suitable modifications of the salen ligand to inhibit attack at the imine carbons could increase the lifetime of the epoxidation catalysts.

The oxidation of ascorbic acid (H2A) by [RuVI(N)(L)(MeOH)]+ in aqueous acidic solutions has the following stoichiometry: 2[RuVI(N)] + 3H2A → 2[RuIII(NH2-HA)]+ + A. Mechanisms involving HAT/N-rebound at low pH (≤2) and nucleophilic attack at the nitride at high pH (≥5) are proposed. [ABSTRACT FROM AUTHOR]

A double-helical dicobalt(II) complex [Co2(spy)2](ClO4)4 (spy = 2,2':6',2'':6'',2''':6''',2'''':6'''',2'''''-sexipyridine) (1) is found to catalyze visible light-induced water oxidation by [Ru(bpy)3]2+/Na2S2O8, with a maximum turnover number of 442. Several lines of evidence suggest that 1 functions as amolecular catalyst and does not produce any CoOx in water oxidation. [ABSTRACT FROM AUTHOR]

The preparation of a number of binuclear (salen)osmium phosphinidine and phosphiniminato complexes using various strategies are described. Treatment of [OsVI(N)(L1)(sol)](X) (sol = H2O or MeOH) with PPh3affords an osmium(iv) phosphinidine complex [OsIV{N(H)PPh3}(L1)(OMe)](X) (X = PF61a, ClO41b). If the reaction is carried out in CH2Cl2in the presence of excess pyrazine the osmium(iii) phosphinidine species [OsIII{N(H)PPh3}(L1)(pz)](PF6) 2can be generated. On the other hand, if the reaction is carried out in CH2Cl2in the presence of a small amount of H2O, a μ-oxo osmium(iv) phosphinidine complex is obtained, [(L1){PPh3N(H)}OsIV–O–OsIV{N(H)PPh3}(L1)](PF6)23. Furthermore, if the reaction of [OsVI(N)(L1)(OH2)]PF6with PPh3is done in the presence of 2, the μ-pyrazine species, [(L1){PPh3N(H)}OsIII–pz–OsIII{N(H)PPh3}(L1)](PF6)24can be isolated. Novel binuclear osmium(iv) complexes can be prepared by the use of a diphosphine ligand to attack two OsVIN. Reaction of [OsVI(N)(L1)(OH2)](PF6) with PPh2–CC–PPh2or PPh2–(CH2)3–PPh2in MeOH affords the binuclear complexes [(MeO)(L1)OsIV{N(H)PPh2–R–PPh2N(H)}OsIV(L1)(OMe)](PF6)2(R = CC 5, (CH2)36). Reaction of [OsVI(N)(L2)Cl] with PPh2FcPPh2generates a novel trimetallic complex, [Cl(L2)OsIV{NPPh2–Fc–PPh2N}OsIV(L2)Cl] 7. The structures of 1b, 2, 3, 4, 5and 7have been determined by X-ray crystallography. [ABSTRACT FROM AUTHOR]

A polypyridyl ruthenium(ii) complex, cis-[RuII(2,9-Me2phen)2(H2O)2]2+, has been adsorbed onto the cation-exchange resins Dowex-50W and Chelex-100. The potential use of the supported ruthenium(ii) complex as catalyst for the oxidative degradation of organic pollutants in water has been investigated using bisphenol A, an emerging endocrine disruptor, as substrate; and the environmentally friendly H2O2as oxidant. These solid-supported catalysts are found to be efficient for the degradation of bisphenol A in aqueous solution by H2O2under ambient conditions. The intermediates and products formed during the oxidative degradation of bisphenol A by these catalytic systems have been identified and a mechanism is proposed. The supported catalysts are easily recovered by simple filtration and display no loss of activity when recycled. [ABSTRACT FROM AUTHOR]

Treatment of [NnBu4][OsVI(N)Cl4] with a stoichiometric amount of H2L (L = N,N′-bis(salicylidene)-o-cyclohexylenediamine dianion) in the presence of PF6−or ClO4−in MeOH affords [OsVI(N)(L)(OH2)](PF6) 1aand [OsVI(N)(L)(CH3OH)](ClO4) 1b, respectively. The structure of 1bhas been determined by X-ray crystallography and the OsN bond distance is 1.627(3) Å. In the presence of a N-donor heterocyclic ligand in CH3CN, 1areacts at room temperature to afford the mixed-valence μ-N2(salen)osmium species [(X)(L)OsIII–NN–OsII(L)(X)](PF6), 2–14(X = py 2; 4-Mepy 3; 4-tBupy 4; pz 5; 3-Mepz 6; 3,5-Me2pz 7; Im 8; 1-MeIm 9; 2-MeIm 10; 4-MeIm 11; 1,2-Me2Im 12; 2-Meozl 13; 4-MeTz 14). These complexes are formed by ligand-induced NN coupling of two [OsVIN]+to give initially [OsIII–N2–OsIII]2+, which is then reduced to give the more stable mixed-valence species [OsIII–N2–OsII]+. Cyclic voltammograms (CVs) of 2–14show two reversible couples, attributed to OsIII,III/OsIII,IIand OsIII,II/OsII,II. The large comproportionation constants (Kcom) of (5.36–82.3) × 1013indicate charge delocalization in these complexes. The structures of 3and 14have been determined by X-ray crystallography, the salen ligands are in uncommon cis-β configuration. Oxidations of 4and 14by [Cp2Fe](PF6) afford the symmetrical species [(X)(L)OsIII–NN–OsIII(L)(X)](PF6)2(X = 4-tBupy 15; 4-MeTz 16). These are the first stable μ-N2diosmium(iii,iii) complexes that have been characterized by X-ray crystallography. [ABSTRACT FROM AUTHOR]

An oxo-bridged diruthenium(iii) complex containing pyrazolato and pyrazole ligands is stable against ascorbic-acid reduction, induces apoptosis (60%, 48 h) against HeLa cells at 10 μM level and exhibits promising anti-angiogenic activity at its sub-cytotoxic concentrations. Other mononuclear ruthenium(iii) complexes containing pyrazole ligands [Ru(pz)4X2]+exhibit dual anti-angiogenic and cytotoxic properties. [ABSTRACT FROM AUTHOR]

A series of cyano-bridged LnIIIRuIII2 coordination polymers, Ph4P{Ln(NO3)2[Ru(acac)2(CN)2]2} [Ln = Tb (1), Dy (2), Er (3), Gd (4); Hacac = acetylacetone] have been synthesized by the reaction of Ln(NO3)3 with trans-Ph4P[Ru- (acac)2(CN)2] in methanol. X-ray crystallographic determination reveals that these compounds are isostructural and have a wavy (4,4) layer structure with the Ln3+ ions bridged by trans-[Ru(acac)2(CN)2]. Magnetic studies shows that the magnetic coupling between the Ln(lll) and Ru(III) ions through the cyano bridges in 1-4 is negligibly weak. [ABSTRACT FROM AUTHOR]