Comparative study of three magnetic nano-particles (FeSO4, FeSO4/SiO2, FeSO4/SiO2/TiO2) in plasmid DNA extraction

Recent updates on Magnetic Nano-Particles (MNPs) based separation of nucleic acids have received more attention due to their easy manipulation, simplicity, ease of automation and cost-effectiveness. It has been indicated that DNA molecules absorb on solid surfaces via hydrogen-bonding, and hydrophobic and electrostatic interactions. These properties highly depend on the surface condition of the solid support. Therefore, surface modification of MNPs may enhance their functionality and specification. In the present study, we functionalized Fe₃O₄ nano-particle surface utilizing SiO₂ and TiO₂ layer as Fe₃O₄/SiO₂ and Fe₃O₄/SiO₂/TiO₂ and then compare their functionality in the adsorption of plasmid DNA molecules with the naked Fe₃O₄ nano-particles. The result obtained showed that the purity and amount of DNA extracted by Fe₃O₄ coated by SiO₂ or SiO₂/TiO₂ were higher than the naked Fe₃O₄ nano-particles. Furthermore, we obtained pH 8 and 1.5 M NaCl as an optimal condition for desorption of DNA from MNPs. The result further showed that, 0.2 mg nano-particle and 10 min at 55 °C are the optimal conditions for DNA desorption from nano-particles. In conclusion, we recommended Fe₃O₄/SiO₂/TiO₂ as a new MNP for separation of DNA molecules from biological sources.     

Inhibition by cupric ions of the hydration of CO2 catalyzed by carbonic anhydrase II

The inhibition by cupric ions of the hydration of CO₂ catalyzed by carbonic anhydrase II is interesting because of the results of Tuet al. obtained at chemical equilibrium, indicating that Cu²⁺ inhibits specifically a proton transfer in the catalytic pathway. We have measured this inhibition at steady state, using stopped-flow methods. The inhibition by Cu²⁺ of the hydration of CO₂ catalyzed by carbonic anhydrase II had aK_I near 1×10^–6 M atpH 7.0 and gave inhibition that is noncompetitive atpH 6.0 and mixed, but close to uncompetitive, atpH 6.8. ThepH dependence of this binding is consistent with a binding site for Cu²⁺ on the enzyme with apK_a near 7. The binding interaction between Cu²⁺ and the fluorescent inhibitor 5-dimethylaminonaphthalene-l-sulfonamide on carbonic anhydrase II was noncompetitive, indicating that the binding site for Cu²⁺ is distinct from the coordination sphere of zinc in which the actual interconversion of CO₂ and HCO₃^– and the binding of sulfonamides takes place.     

New molybdenum(V) complexes based on the {Mo2O4} structural core with esters or anions of malonic and succinic acid

A series of malonato complexes of molybdenum(V) was prepared by reacting (PyH)₅[MoOCl₄(H₂O)]₃Cl₂ or (PyH)_n[MoOBr₄]_n with malonic acid (H₂mal) or a half-neutralized acid, hydrogen malonate (Hmal⁻), at ambient conditions: (PyH)₃[Mo₂O₄Cl₄(μ₂-Hmal)] · CH₃CN (1), (PyH)₃[Mo₂O₄Br₄(μ₂-Hmal)] · CH₃CN (2), (PyH)₂[Mo₂O₄Cl(η²-mal)(μ₂-Hmal)Py] (3), (3,5-LutH)₂(H₃O) [Mo₂O₄(η²-mal)₂(μ₂-Hmal)] (4), (PyH)[Mo₂O₄Cl₂(μ₂-Memal)Py₂] (5), (3,5-LutH)[Mo₂O₄Cl₂(μ₂-Memal)(3,5-Lut)₂] (6), (PyH)[Mo₂O₄Cl₂(μ₂-Etmal)Py₂] (7), (3,5-LutH)[Mo₂O₄Cl₂(μ₂-Prmal)(3,5-Lut)₂] (8) and [{Mo₂O₄(μ₂-Memal)Py₂}₂(μ₂-OCH₃)₂] (9) (where Py = pyridine, C₅H₅N; PyH⁺ = pyridinium cation, C₅H₅NH⁺; 3,5-Lut = 3,5-lutidine, C₇H₉N; 3,5-LutH⁺ = 3,5-lutidinium cation, C₇H₉NH⁺; mal²⁻ = malonate, ⁻OOCCH₂COO⁻; Memal⁻ = monomethyl malonate, ⁻OOCCH₂COOCH₃; Etmal⁻ = monoethyl malonate, ⁻OOCCH₂COOC₂H₅ and Prmal⁻ = monopropyl malonate, ⁻OOCCH₂COOC₃H₇). The complex anions of compounds 1-8 have a common structural feature: a dinuclear, singly metal-metal bonded {Mo₂O₄}²⁺ core with the carboxylate moiety of the malonato ligand coordinated in a syn-syn bidentate bridging manner to the pair of metal atoms. The remaining four coordination sites of the {Mo₂O₄}²⁺ core are occupied with halides in 1 and 2, with halides/pyridine ligands in 5-8, with a pair of bidentate malonate ions in 4 and with the combination of all in 3. The neutral molecules of 9 consist of two {Mo₂O₄}²⁺ cores linked with a pair of methoxide ions into a chain-like, tetranuclear cluster. An esterification of malonic acid was observed to take place in the reaction mixtures containing alcohols. Solvothermal reactions with malonic acid carried out at 115 °C produced anionic acetato complexes as found in (PyH)[Mo₂O₄Cl₂(μ₂-OOCCH₃)Py₂] · Py (10), (PyH)[Mo₂O₄Cl₂(μ₂-OOCCH₃)Py₂] (11), (3,5-LutH)[Mo₂O₄Cl₂(μ₂-OOCCH₃)(3,5-Lut)₂] (12) and (4-MePyH)₃[Mo₂O₄Cl₂(μ₂-OOCCH₃)(4-MePy)₂]₂Cl (13) (4-MePy = 4-methylpyridine, C₆H₇N). The acetate coordinated in the syn-syn bidentate bridging mode in all. Reactions of (PyH)₅[MoOCl₄(H₂O)]₃Cl₂ with succinic acid (H₂suc) at ambient conditions resulted in a complex with a half-neutralized acid, (PyH)[Mo₂O₄Cl₂(μ₂-Hsuc)Py₂] · Py (14) (Hsuc⁻ = hydrogen succinate, ⁻OOC(CH₂)₂COOH), while those carried out at 115 °C in a tetranuclear succinato complex, (4-MePyH)₂[{Mo₂O₄Cl₂(4-MePy)₂}₂(μ₄-suc)] (15) (suc²⁻ = succinate, ⁻OOC(CH₂)₂COO⁻). The tetranuclear anion of 15 consists of two {Mo₂O₄}²⁺ cores covalently linked with a tetradentate succinato ligand. The compounds were fully characterized by infrared vibrational spectroscopy, elemental analyses and X-ray diffraction studies.     

A new mixed-valence hexanuclear cobalt complex, [Co4Co2(dea)2(Hdea)4)(piv)4](ClO4)2·H2O: Synthesis, crystal structure and magnetic properties

A new Co^II/Co^III hexanuclear complex, [Co₄^IICo₂^III(dea)₂(Hdea)₄)(piv)₄](ClO₄)₂·H₂O 1, has been obtained by reacting cobalt(II) perchlorate, diethanolamine, and pivalic acid (H₂dea = diethanolamine and piv = pivalato anion). The cobalt ions are held together by four μ₃ and four μ₂ alkoxo bridges as well as by four syn-syn carboxylato groups. The hexanuclear motif contains four Co(II) and two Co(III) ions. The {Co^II₄Co^III₂(μ₂-O)₄(μ₃-O)₄} core can be described as a four face-sharing monovacant and bivacant distorted heterocubane units. The cobalt(III) ions are hexacoordinated. Two of the cobalt(II) are hexacoordinated, while the two others are pentacoordinated with a bipyramidal stereochemistry. The magnetic properties of 1 have been investigated in the temperature range 1.9-300 K. Compound 1 exhibits an overall antiferromagnetic behaviour with a ground singlet spin state.     

Emission of N2O, N2, CH4, and CO2 from constructed wetlands for wastewater treatment and from riparian buffer zones

We measured nitrous oxide (N₂O), dinitrogen (N₂), methane (CH₄), and carbon dioxide (CO₂) fluxes in horizontal and vertical flow constructed wetlands (CW) and in a riparian alder stand in southern Estonia using the closed chamber method in the period from October 2001 to November 2003. The replicates’ average values of N₂O, N₂, CH₄ and CO₂ fluxes from the riparian gray alder stand varied from −0.4 to 58 μg N₂O-N m⁻² h⁻¹, 0.02–17.4 mg N₂-N m⁻² h⁻¹, 0.1–265 μg CH₄-C m⁻² h⁻¹ and 55–61 mg CO₂-C m⁻² h⁻¹, respectively. In horizontal subsurface flow (HSSF) beds of CWs, the average N₂ emission varied from 0.17 to 130 and from 0.33 to 119 mg N₂-N m⁻² h⁻¹ in the vertical subsurface flow (VSSF) beds. The average N₂O-N emission from the microsites above the inflow pipes of the HSSF CWs was 6.4–31 μg N₂O-N m⁻² h⁻¹, whereas the outflow microsites emitted 2.4–8 μg N₂O-N m⁻² h⁻¹. In VSSF beds, the same value was 35.6–44.7 μg N₂O-N m⁻² h⁻¹. The average CH₄ emission from the inflow and outflow microsites in the HSSF CWs differed significantly, ranging from 640 to 9715 and from 30 to 770 μg CH₄-C m⁻² h⁻¹, respectively. The average CO₂ emission was somewhat higher in VSSF beds (140–291 mg CO₂-C m⁻² h⁻¹) and at the inflow microsites of HSSF beds (61–140 mg CO₂-C m⁻² h⁻¹). The global warming potential (GWP) from N₂O and CH₄ was comparatively high in both types of CWs (4.8 ± 9.8 and 6.8 ± 16.2 t CO₂ eq ha⁻¹ a⁻¹ in the HSSF CW 6.5 ± 13.0 and 5.3 ± 24.7 t CO₂ eq ha⁻¹ a⁻¹ in the hybrid CW, respectively). The GWP of the riparian alder forest from both N₂O and CH₄ was relatively low (0.4 ± 1.0 and 0.1 ± 0.30 t CO₂ eq ha⁻¹ a⁻¹, respectively), whereas the CO₂-C flux was remarkable (3.5 ± 3.7 t ha⁻¹ a⁻¹). The global influence of CWs is not significant. Even if all global domestic wastewater were treated by wetlands, their share of the trace gas emission budget would be less than 1%.     

Structural characterization, electrochemistry, and spectroelectrochemistry of trans-dioxorhenium(V) complex with 4-methoxypyridine, [ReO2(4-MeOpy)4]PF6, and characterization of [ReO2(4-MeOpy)4] generated electrochemically

Crystal structure of [ReO₂(4-MeOpy)₄][PF₆] (4-MeOpy = 4-methoxypyridine) complex has been examined by the single crystal X-ray analytical method. This complex shows a trans-dioxo geometry (average Re-O bond length = 1.766(2) Å) and its equatorial plane is occupied by four 4-MeOpy molecules (average Re-N bond length = 2.156(4) Å). Electrochemical reaction of [ReO₂(4-MeOpy)₄]⁺ in CH₃CN solution containing tetra-n-butylammonium perchlorate as a supporting electrolyte has been studied using cyclic voltammetry at 24 °C. Cyclic voltammograms show one redox couple around 0.65 V (E_pa) and 0.58 V (E_pc) [versus ferrocene/ferrocenium ion redox couple, (Fc/Fc⁺)]. Potential differences between two peaks (ΔE_p) at scan rates in the range from 0.01 to 0.10 V s⁻¹ are 65 mV, which is almost consistent with the theoretical ΔE_p value (59 mV) for the reversible one electron transfer reaction at 24 °C. The ratio of anodic peak currents to cathodic ones is 1.04 ± 0.03 and the (E_pa + E_pc)/2 value is constant, 0.613 ± 0.001 V versus Fc/Fc⁺, regardless of the scan rate. Spectroelectrochemical experiments have also been carried out by applying potentials from 0.40 to 0.77 V versus Fc/Fc⁺ with an optically transparent thin layer electrode. It was found that the UV-visible absorption spectra show clear isosbestic points at 228, 276, and 384 nm, and that the electron stoichiometry is evaluated as 1.03 from the Nernstian plot. These results indicate that the [ReO₂(4-MeOpy)₄]⁺ complex is oxidized reversibly to the [ReO₂(4-MeOpy)₄]²⁺ complex. Furthermore, it was clarified that the [ReO₂(4-MeOpy)₄]²⁺ in CH₃CN has the characteristic absorption bands at 236, 278, 330, 478, and 543 nm and their molar absorption coefficients are 4.3 × 10⁴, 4.5 × 10³, 1.0 × 10⁴, and 6.1 × 10³ M⁻¹ cm⁻¹ (M = mol dm⁻³), respectively.     

Specificity of receptors for leukotrienes A4, B4, C4, D4, E4 and histamine on the guinea-pig lung parenchyma. Effect of FPL-55712 and desensitization of the myotropic activity

The novel metabolites of arachidonic acid, leukotriene (LT) A₄, B₄, C₄, D₄ and E₄ have potent myotropic activity on guinea-pig lung parenchymal strip . The receptors responsible for their action were characterized using desensitization experiments and the selective SRS-A antagonist, FPL-55712. During the continuous infusion of LTB₄, the tissues became desensitized to LTB₄ but were still responsive to histamine, LTA₄, LTC₄, LTD₄ and LTE₄. When LTD₄ was infused continuously, the lung strips contracted to LTB₄ and histamine but were no longer responsive to LTA₄, LTC₄, LTD₄ and LTE₄. Furthermore, FPL-55712 (10 ng ml⁻¹− 10 ug ml⁻¹) produced dose-dependent inhibitions of LTA₄, LTC₄, LTD₄ and LTE₄ without inhibiting the contraction to LTB₄ and histamine. On the basis of these results, it appears that the guinea-pig lung parenchyma may have one type of receptor for LTB₄ and another for LTD₄; LTA₄, LTC₄ and LTE₄ probably act on the LTD₄ receptor.     

Phosphane effects on formation and reactivity of [Ru(L)(PR3)(`N2Me2S2')] complexes with L=N2, N2H4, NH3, and CO

Metal-sulfur complex fragments, to which small molecules like N₂, N₂H₂, N₂H₄, NH₃, or CO can bind, are desirable model compounds concerning enzymatic N₂ fixation.This paper reports on the effects of the phosphane co-ligand on formation and reactivity of [Ru(L)(PR₃)(`N<sub>2</sub>Me<sub>2</sub>S<sub>2</sub>')] [`N₂Me₂S₂'²⁻=1,2-ethanediamine-N,N^′-dimethyl-N,N^′-bis(2-benzenethiolate)(2−)] complexes with nitrogenase relevant ligands, especially N₂, N₂H₄, NH₃, and CO.Treatment of [Ru(NCCH₃)₄Cl₂] with Li₂`N<sub>2</sub>Me<sub>2</sub>S<sub>2</sub>', excessive LiOMe, bulky PPh<sub>3</sub> or PCy<sub>3</sub>, respectively, led to the formation of two series of [Ru(L)(PR<sub>3</sub>)(`N₂Me₂S₂')] complexes [for R=Ph: 1b, 1c (L=NCCH₃), 6b (L=N₂H₄), 7b (L=N₂), 8b_1-3 (L=CO), 9b (L=NH₃); for R=Cy: 1a (L=NCCH₃), 6a (L=N₂H₄), 7a (L=N₂), 8a (L=CO), 9a (L=NH₃)]. While the use of PPh₃ (θ=145°) yielded cis,trans and cis,cis isomers of [Ru(NCCH₃)(PPh₃)(`N<sub>2</sub>Me<sub>2</sub>S<sub>2</sub>')] (1b, 1c), no isomer formation was observed with the bulkier phosphane PCy<sub>3</sub> (θ=170°). Sterically less demanding phosphanes (θ=118-132°) afforded bisphosphane complexes [Ru(PR<sub>3</sub>)<sub>2</sub>(`N₂Me₂S₂')] [2d (R=Me), 2e (R=Et), 2f (R=nPr), and 2g (R=nBu)], which were practically inert and could only be converted in two cases and under drastic reaction conditions into the CO complexes [Ru(CO)(PR₃)(`N<sub>2</sub>Me<sub>2</sub>S<sub>2</sub>')] [4e (R=Et), 4f (R=nPr)]. The chelating bidentate phosphane dppe (bisdiphenylphosphanoethane) yielded exclusively the mononuclear complex [Ru(dppe)(`N₂Me₂S₂')] (3).     

Hydrothermal synthesis and structure of an open framework Co0.7Zn1.3(PO4)2(NH3-CH2CH2NH3) and Co6.2(OH)4(PO4)4Zn1.80, a new adamite type phase

The hydrothermal reaction of cobalt(II)oxalate di-hydrate, zinc oxide, and triethyl-orthophosphate, using 1,2-diaminoethane as structure directing template in water, produced two major crystal phases in almost equal amount: the purple crystals of [NH₃-CH₂CH₂NH₃][Co_0.7Zn_1.3(PO₄)₂] (1) and the red burgundy crystals of Co_6.2(OH)₄(PO₄)₄Zn_1.80 (2), a new adamite type phase. The structure of [NH₃-CH₂CH₂NH₃] [Co_0.7Zn_1.3(PO₄)₂] (1) exhibits a 3D open framework built from PO₄ and (Co/Zn)O₄ tetrahedra, and (Co/Zn)O₅ trigonal bipyramids, forming two major channels, an 8-membered ring channel and a 16-membered ring channel, that host the ethanediammonium ions. The Co_6.2(OH)₄(PO₄)₄Zn_1.80 (2) is isomorphous with adamite-type M₂(OH)XO₄ structure, with a condensed vertex and edge sharing network of (Co/Zn)O₅, and distorted CoO₆, and PO₄ subunits. The cobalt preference for higher coordination numbers is displayed in this structure, where the octahedral sites are wholly occupied by cobalt. Thermal analysis confirmed that these compounds display high thermal stability.     

Heterobimetallic aggregates of copper(I) with thiotungstates and thiomolybdates. Synthesis and characterization of polymeric (NEt4)3[Cu4(NCS)5WS4], (NEt4)2[(CuNCS)3WS4] and (NEt4)2[(CuNCS)4WS4], M = Mo, W

Reaction of (NEt₄)₂MS₄ (M = Mo, W) with CuCl and KSCN (or NH₄SCN) in acetone or acetonitrile affords a new set of mixed metal–sulfur compounds: infinite anionic chains Cu₄(NCS)₅MS_4³⁻ (1,2), (CuNCS)₃WS_4²⁻ (3) and two dimensional polymeric dianions (CuNCS)₄MS_4²⁻ (4,5). Crystal of 1 (M = W) and 3 are triclinic, space group P1(1:a = 10.356(2),b = 15.039(1),c = 17.356(2)Å, = 78.27(1)°, β = 88.89(2)° and γ = 88.60(1)°,Z = 2,R = 0.04 for 3915 independent data;3:a = 8.449(2),b = 14.622(4),c = 15.809(8)Å, = 61.84(3)°, β = 73.67(3)° and γ = 78.23(2)°,Z = 2,R = 0.029 for 6585 independent data). Crystals of 4 (M = W) and 5 (M = Mo) are monoclinic, space group P2₁/m,Z = 2 (4:a = 12.296(4),b = 14.794(4),c = 10.260(3)Åand β = 101.88(3)°,R = 0.034 for 4450 independent data;5:a = 12.306(2),b = 14.809(3),c = 10.257(2)Åand β = 101.99(3)°,R = 0.043 for 3078 independent data). The crystal structure determinations of 4 and 5 show that four edges of the tetrahedral MS_4²⁻ core are coordinated by copper atoms forming WS₄Cu₄ aggregates linked by eight-membered Cu(NCS)₂Cu rings. A two-dimensional network is thus formed in the diagonal (101) plane. The space between the anionic two-dimensional networks is filled with the NEt_4⁺ cations. Additional NCS groups lead to the [Cu₄(NCS)₅WS₄]³⁻ (1) trianion connected by NCS bridges forming pseudo-dimers. These latter are held together by weak CuS(NCS) interactions giving rise to infinite chains along a direction parallel to [100]. In contrast complex3 develops infinite chains from WS₄Cu₃ aggregates with the same Cu(NCS)₂Cu bridges as in 4 and 5. These chains are running along a direction parallel to [010]. The structural data of the different types of polymeric compounds containing MS_4²⁻ and CuNCS have been used to interpret vibrational spectroscopic data of the thiocyanate groups.     

Utility of d4-PGE2 as an internal standard to quantify endogenous levels of PGE1, PGE2, 190H PGE1 and 190H PGE2 in human seminal fluid by GC-MS-SIM

Four prostaglandins-PGE₁, PGE₂, 190H PGE₁ and 190H PGE₂-were quantified in human seminal fluid by GC-MS-SIM using only the internal standard, d₄-PGE₂. Methods and calculations were developed to minize errors inherent in using only one internal standard for quantifying four closely related prostaglandins. Preliminary data concerning the statistical significance of the differences found between PGE and 190H PGE levels in fertile, azospermic and oligospermic men are reported.     

Biological oxidation of hydrogen in soils flushed with a mixture of H2, CO2, O2 and N2

Abstract A stainless steel cylinder filled with soil was flushed upstream with a H₂/CO₂/air mixture. The consequence was a strong enrichment of the aerobic, autotrophic hydrogen-oxidising microflora, which reached densities enabling them to oxidize 84.5 ml H₂· dm⁻²· h⁻¹ in the first 25-cm layer. H₂ concentration profiles, hydrogen uptake activity and cell numbers correlated well with each other. Most of the organisms isolated were dinitrogen fixers. Thus, soils containing hydrogen-oxidising bacteria may act as a biological shield between H₂-rich environments and air, and may be utilized as biofilters, e.g., in the waste-processing industry.     

Thermal deamination kinetics of the nickel-containing chabazite-like aluminophosphate, Ni(NH2-CH2-CH2-NH2)2(AlPO4)6(OH)2, deposition of nanocrystalline NiO particles

Thermogravimetrical analysis has been used to study the kinetics of thermal deamination of bis(ethylenediamine)nickel(II)-containing aluminophosphate (Ni-CHA) which is a precursor of nickel(II)-containing chabazite-like AlPO₄-34. The deamination occurs as a single-step kinetic process which is best described by the contracting cylinder model. The obtained activation energy of 200 kJ/mol is mainly a reflection of the strong Ni-N coordination bond. The thermal decomposition of Ni-CHA results in the deposition of crystalline NiO particles homogeneously dispersed in the AlPO₄-34 lattice. Average particle size was found to be about 5 nm. The study confirms that the thermal decomposition of amine complexes of Ni(II) encapsulated inside the microporous aluminophosphate host can be a suitable method for obtaining fine nano-oxide particles.     

Syntheses and X-ray structures of a series of V2S4(RCS2)4 (R=alkoxy, dialkylamino) complexes

A simple synthetic procedure leading to the V₂(S₂)₂(RCS₂)₄ species (R=Et₂N (1), cyclo-C₄H₈N (2), n-Bu₂N (3), EtO (4), i-PrO (5)) has been developed. X-ray structures of 3 and 5 have been reported, featuring the centrosymmetric molecules with VV distances 2.850(3) Å for 3 and 2.838(2) Å for 5.The FAB mass spectra were recorded. In all cases molecular peaks are observed. Fragmentation patterns are discussed.     

Supramolecular assemblies of new 2-D complexes: Syntheses, crystal structures, spectroscopic and magnetic properties of {[MnAu2(CN)4(NITpPy)2(H2O)2]}n and {[Co(N(CN)2)2(NITpPy)2(H2O)2]}n

Two new complexes, {[MnAu₂(CN)₄(NITpPy)₂(H₂O)₂]}_n (1) and {[Co(N(CN)₂)₂(NITpPy)₂(H₂O)₂]}_n (2), have been synthesized and characterized. The single-crystal X-ray analysis for the complexes 1 and 2 demonstrates that each M(II) (M = Mn or Co) ion assumes a distorted octahedral MN₄O₂ coordination polyhedron. Four nitrogen atoms come from the cyanide groups and the pyridyl rings in a common plane, and two oxygen atoms come from the H₂O molecules in trans-positions. The structures of complexes 1 and 2 illustrate that aurophilicity and/or hydrogen bonding interactions play important roles in increasing dimensionality. Magnetic investigations on complexes 1 and 2 show the presence of weak antiferromagnetic interactions.     

Spectral properties and bio-activity of copper(II) clofibriates, part III: crystal structure of Cu(clofibriate)2(2-pyridylmethanol)2, Cu(clofibriate)2(4-pyridylmethanol)2(H2O) dihydrate, and Cu2(clofibriate)4(N,N-diethylnicotinamide)2

New copper(II) clofibriates (clof, {2-(4-chlorophenoxy)-2-methylpropionic or 2-(4-chlorophenoxy)isobutyric acid}) of composition Cu(clof)₂L₂ (where L=2-pyridylmethanol (2-pymeth) (1), N-methylnicotinamide (Menia) (4), N,N-diethylnicotinamide (Et₂nia) (5), isonicotinamide (isonia) (7) or methyl-3-pyridylcarbamate (mpc) (8)), [Cu(clof)₂(4-pymeth)₂(H₂O)] · 2H₂O (4-pymeth=4-pyridylmethanol) (2 · 2H₂O) and Cu(clof)₂L (where L=4-pymeth (3) or Et₂nia (6)) have been prepared and spectroscopically characterized. All the Cu(clof)₂L₂ compounds seem to possess distorted octahedral copper(II) stereochemistry with differing tetragonal distortions. An X-ray analysis of 1 was carried out and it featured a tetragonal-bipyramidal geometry around the copper(II) atom. X-ray analysis of 2 · 2H₂O featured a square-pyramidal geometry around copper(II) atom. Both the Cu(clof)₂L compounds seem to consist of a binuclear unit of tetracarboxylate type bridging. An X-ray analysis of 6 revealed typical binuclear paddle-wheel type structure, consisting of two copper(II) atoms in square-pyramidal geometry bridged by four carboxylate anions in the xy-plane. All complexes under study were characterized by EPR and electronic spectroscopy. The antimicrobial effects have been tested on various strains of bacteria, yeasts and filamentous fungi.     

Synthesis, spectroscopic and structural characterization of adducts of stoichiometry CuX:dppe (1:2) (X = I, ClO4, BH4, O3SCF3, SCN, dppe = Ph2P(CH2)2PPh2)

Syntheses and spectroscopic features (IR, NMR and ESI MS) are reported for five 1:2 adducts of CuX with dppe (X = I, ClO₄, NCS, O₃SCF₃ (tfs) BH₄; dppe = Ph₂P(CH₂)₂PPh₂). ESI MS and ³¹P NMR spectroscopy indicate that these species dissociate in solution yielding free diphosphine and 3:2 species. A single crystal X-ray structure determination has been carried out on Cu(dppe)₂NCS defining a four-coordinate complex of the form [(P,P′-dpex)M(P-dpex)X] for M = Cu, the thiocyanate being N-bound; the ionic [Cu(P,P′-dppe)₂]tfs has also been structurally characterized.     

Synthesis, crystal structure and vibrational spectroscopy of a novel mixed ligands Ni(II) pentaborate: [Ni(C4H10N2)(C2H8N2)2][B5O6(OH)4]2

A novel organic-inorganic hybrid pentaborate [Ni(C₄H₁₀N₂)(C₂H₈N₂)₂][B₅O₆(OH)₄]₂ has been synthesized by hydrothermal reaction and characterized by FT-IR, Raman spectroscopy, elemental analyses and DTA-TGA. Its crystal structure was determined from single crystal X-ray diffraction. The structure consists of isolated polyborate anion [B₅O₆(OH)₄]⁻ and nickel complex cation of [Ni(C₄H₁₀N₂)(C₂H₈N₂)₂]²⁺, in which the two kinds of ligands come from the decomposition of triethylenetriamine material. The [B₅O₆(OH)₄]⁻ units are connected to one another through hydrogen bonds, forming a three-dimensional framework with large channel along the a and c axes, in which the templating [Ni(C₄H₁₀N₂)(C₂H₈N₂)₂]²⁺ cations are located. The assignments of the record FT-IR absorption frequencies and Raman shifts were given.     

Synthesis and characterization of SrCu2(O2CR)3(bdmap)3 and Bi2(O2CCH3)4(bdmap)2(H2O) (R = CH3, CF3; bdmap = 1,3-bis(dimethylamino)-2-propanolato)

New mixed metal complexes SrCu₂(O₂CR)₃(bdmap)₃ (R = CF₃ (1a), CH₃ (1b)) and a new dinuclear bismuth complex Bi₂(O₂CCH₃)₄(bdmap)₂(H₂O) (2) have been synthesized. Their crystal structures have been determined by single-crystal X-ray diffraction analyses. Thermal decomposition behaviors of these complexes have been examined by TGA and X-ray powder diffraction analyses. While compound 1a decomposes to SrF₂ and CuO at about 380°C, compound 1b decomposes to the corresponding oxides above 800°C. Compound 2 decomposes cleanly to Bi₂O₃ at 330°C. The magnetism of 1a was examined by the measurement of susceptibility from 5–300 K. Theoretical fitting for the susceptibility data revealed that 1a is an antiferromagnetically coupled system with g = 2.012(7), −2J = 34.0(8) cm⁻¹. Crystal data for 1a: C₂₇H₅₁N₆O₉F₉Cu₂Sr/THF, monoclinic space group P2₁/m, A = 10.708(6), B = 15.20(1), C = 15.404(7) Å, β = 107.94(4)°, V = 2386(2) ų, Z = 2; for 1b: C₂₇H₆₀N₆O₉Cu₂Sr/THF, orthorhombic space group Pbcn, A = 19.164(9), B = 26.829(8), C = 17.240(9) Å, V = 8864(5) ų, Z = 8; for 2: C₂₂H₄₈O₁₁N₄Bi₂, monoclinic space group P2₁/c, A = 17.614(9), B = 10.741(3), C = 18.910(7) Å, β = 109.99(3)°, V = 3362(2) ų, Z = 4.     

Effects of raised CO2 on potential CH4 production and oxidation in, and CH4 emission from, a boreal mire

1 In a glasshouse experiment we studied the effect of raised CO₂ concentration (720 p.p.m.) on CH₄ emission at natural boreal peat temperatures using intact cores of boreal peat with living vascular plants and Sphagnum mosses. After the end of the growing season half of the cores were kept unnaturally warm (17–20 °C). The potential for CH₄ production and oxidation was measured at the end of the emission experiment.
2 The vascular cores ('Sedge') consisted of a moss layer with sedges, and the moss cores (' Sphagnum ') of Sphagnum mosses (some sedge seedlings were removed by cutting). Methane efflux was 6–12 times higher from the Sedge cores than from the Sphagnum cores. The release of CH ₄ from Sedge cores increased with increasing temperature of the peat and decreased with decreasing temperature. Methane efflux from Sphagnum cores was quite stable independent of the peat temperatures.
3 In both Sedge and Sphagnum samples, CO₂ treatment doubled the potential CH₄ production but had no effect on the potential CH₄ oxidation. A raised concentration of CO₂ increased CH₄ efflux weakly and only at the highest peat temperatures (17–20 °C).
4 The results suggest that in cool regions, such as boreal wetlands, temperature would restrict decomposition of the extra substrates probably derived from enhanced primary production of mire vegetation under raised CO₂ concentrations, and would thus retard any consequent increase in CH₄ emission.