Search

In this study, PCR amplification of biodegradation related genes from NAR-2 bacterial consortium was accomplished. NAR-2 bacterial consortium consists of Citrobacter freundii A1, Enterococcus casseliflavus C1 and Enterobacter cloacae L17. The amplified genes were sequenced, bioinformatically analyzed and compared with the sequences from GenBank database of National Centre of Biotechnology Information (NCBI) using BLASTn and BLASTp search tools. The assembled sequences represented almost >70% of similarity to biodegradation related genes. These genes may act as a key intermediate enzyme in biodegradation pathway.

The ability of the NAR-2 bacterial consortium, consisting of A1, C1, and L17, to degrade the azo dye model, Remazol Black B (RBB), was studied in an upflow packed-bed reactor for continuous sequential microaerophilic–aerobic batch operations. Continuous decolourisation was performed in a borosilicate glass column (12 mm × 20 mm) packed with surfactant-modified clinoptilolite immobilised by the NAR-2 bacterial consortium. In column bioreactor studies, decolourisation was observed at 45 °C and was carried out by varying the flow rates and dye concentrations in a modified P5 medium with pH 7.0 under microaerophilic conditions. A decolourisation of 95.87 % of 0.1 g/L RBB was achieved at a flow rate of 0.2 mL/min under microaerophilic conditions by the immobilised NAR-2 bacterial consortium. An analysis of the decolourised and biodegradation products of the RBB using total aromatic amines showed that a reduction in the RBB resulted in the formation of aromatic amines. On further aerobic degradation for 15 days, the concentration of the amines dropped significantly, from an initial concentration of 34 to 11 mg/L, following the aerobic batch treatment experiment. The findings of this study showed that SMC can be a support material for bacterial cell immobilisation in a single upflow reactor with intermittent microaerophilic–aerobic operations, and it was found to be suitable and eco-friendly for the degradation of azo dyes.

National Nature Science Foundation of China (NNSFC)[20972129, 91027014]; Research Fund for New Teacher of Higher Education[200803841012]; National Fund for Fostering Talents of Basic Science (NFFTBS)[J1030415]

Two novel mono- and bi-functionalized organoimido derivatives of hexamolybdates bearing the strong electron-withdrawing nitro group, (Bu4N)2[Mo6O17( NAr)2] (1) and (Bu4N)2[Mo6O18( NAr)] (2) (Ar o-NO2–C6H4) have been synthesized for the first time via the reaction of hexamolybdate ions and 2 equivalent of aromatic amines with an excessive dehydrating agent N,N′-dicyclohexylcarbodiimide (DCC). By controlling the amount of DCC, such two derivatives can be selectively prepared in reasonable yields, which have been characterized with UV/vis, IR, 1H NMR, ESI-mass spectrometry and single-crystal X-ray diffraction techniques. The influences of [NAr] ligands and [NAr] incorporation number on properties and supermolecular assembly of such two derivatives have been systematically investigated.

LGe(Se)OH (2) (L = HC[(CMe)(NAr)]2, Ar = 2,6-iPr2C6H3) was obtained by oxidative addition of red selenium to LGeOH (1). Compound 2 was characterized by IR, multinuclear NMR, EI-MS, and single-crystal X-ray diffraction. Furthermore, theoretical calculations of the acid strength (pKa) of compound 2 and LGe(S)OH were carried out by means of density functional theory (DFT).

A kinetically controlled trans bifunctionalized organoimido derivative of hexamolybdate, (n-Bu(4)N)(2){trans-[Mo(6)O(17)(NAr)(2)]} (Ar = 2,6-dimethylphenyl) 1, in which the two 2,6-dimethylphenylimido groups are bonded to hexamolybdate at the trans positions, has been successfully synthesized in ca. 60% yield under mild reaction conditions. Its trans structure has been confirmed by a single-crystal X-ray diffraction study. In the crystals, cluster anions of 1 self-assemble into a 3D netlike structure via two different kinds of C-H...O hydrogen bondings, in which 1D supramolecular rectangular channels containing tetrabutylammonium cations form along the a axis. Compound 1 has also been characterized by (1)H NMR, IR, and UV-vis spectroscopic studies. UV-vis-near-IR reflectance spectroscopy measurements reveal the compound's nature of semiconductivity with an optical energy gap of 2.55 eV.

Reactions between the aluminum(I) monomer LAl (L = HC[(CMe)(NAr)]2, Ar = 2,6-iPr2C6H3) and organic azides (RN3, R = C10H15 (adamantyl), Ph3Si; tBuSi(N3)3) are reported. LAl reacted with the bulky a...

Reaction of LAl (1) or [LAl{η2-C2(SiMe3)2}] (2) {L = HC[(CMe)(NAr)]2, Ar = 2,6-iPr2C6H3} with azobenzene affords a five-membered ring compound [LAl{N(H)-o-C6H4N(Ph)}] (3). In the formation of 3 a three-membered intermediate [LAl(η2-N2Ph2)] (A) is suggested by a [1 + 2] cycloaddition reaction; A is not stable and further rearranges to 3. DFT calculations on similar compounds with modified L' {L' = HC[(CMe)(NPh)]2} show that the complexation energy of the reaction of L'Al with azobenzene to form [L'Al(η2-N2Ph2)] is about–39 kcal mol–1, and the best estimate of the energy difference between [L'Al(η2-N2Ph2)] and [L'Al{N(H)-o-C6H4N(Ph)}] is–76 kcal mol–1. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

In the presence of N, N′-dicyclohexylcarbodiimide (DCC), (Bu4N)2[Mo6O18(NAr)] (1) and (Bu4N)2[Mo6O17(NAr)2] (2), Ar = o-CH3C6H4, have been synthesized via the reaction of [α-Mo8O26]4— with o-toluidine. If the hydrochloride salt of o-toluidine was added into the reactive mixture, only the monofunctionalized imido derivative of [Mo6O19]2— was obtained; the bifunctionalized derivative of [Mo6O19]2— was exclusively synthesized in the presence of non-protonated o-toluidine. The molecular and crystal structures of the hybrid compounds 1 and 2 were determined by X-ray single crystal diffraction, and their UV, IR and NMR spectra were compared. Additionally, a possible reaction mechanism was proposed.

The compounds [MoCl(NAr)2R] (R=CH2CMe2Ph (1) or CH2CMe3(2); Ar=2,6-Pri2C6H3) have been prepared from [MoCl2(NAr)2(dme)] (dme=1,2-dimethoxyethane) and one equivalent of the respective Grignard reagent RMgCl in diethyl ether. Similarly, the mixed-imido complex [MoCl2(NAr)(NBut)(dme)] affords [MoCl(NAr)(NBut)(CH2CMe2Ph)] (3). Chloride substitution reactions of 1 with the appropriate lithium reagents afford the compounds [MoCp(NAr)2(CH2CMe2Ph)] (4) (Cp=cyclopentadienyl), [MoInd(NAr)2(CH2CMe2Ph)] (5) (Ind=Indenyl), [Mo(OBut)(NAr)2(CH2CMe 2Ph)] (6), [MoMe(NAr)2(CH2CMe2Ph)] (7), [MoMe(PMe3)(NAr)2(CH2CMe 2Ph)] (8) (formed in the presence of PMe3) and [Mo(NHAr)(NAr)2(CH2CMe2P h)](9). In the latter case, a by-product {[Mo(NAr)2(CH2CMe2Ph) ]2(μ-O)}(10) has also been isolated. The crystal structures of 1, 4, 5 and 10 have been determined. All possess distorted tetrahedral metal centres with cis near-linear arylimido ligands; in each case (except 5, for which the evidence is unclear) there are α-agostic interactions present.

The nature of the bonding between the two M( μ -NAr # )imido monomers [M = Si, Ge, Sn, Pb; Ar # =C 6 H 3 -2,6-(C 6 H 2 -2,4,6-R 3 ) 2 ; R = Me, iPr] in the {M( μ -NAr # )} 2 dimer is investigated with the help of a newly developed energy and density decomposition scheme as well as molecular dynamics. The approach combines the extended transition state energy decomposition method with the natural orbitals for chemical valence density decomposition scheme within the same theoretical framework. The dimers are kept together by two σ bonds and two π bonds. The σ bonding has two major contributions. The fi rst is a dative transfer of charge from nitrogen to M. It amounts to − 188 kcal/mol for {Si( μ -NAr # )} 2 , − 152 kcal/mol for {Ge( μ -NAr # )} 2 with − 105 kcal/mol for {Sn( μ -NAr # )} 2 , and − 79 kcal/mol for {Pb( μ -NAr # )} 2 . The second is a charge buildup within the ring made up of the two dimers. It amounts to − 82 kcal/mol for M = Si with − 61 kcal/mol for M = Ge and ∼− 50 kcal/mol for M = Sn and Pb. We fi nally have π bonding with a donation of charge from M to nitrogen. It has a modest contribution of ∼− 30 kcal/mol. The presence of isopropyl (iPr) groups is further shown to stabilize{M( μ -NAr # )} 2 [M = Si, Ge, Sn, Pb; Ar # =C 6 H 3 -2,6-(C 6 H 2 -2,4,6-iPr 3 ) 2 ] compared to the methylated derivatives (R = Me) through attractive van der Waals dispersion interactions.

Use of the very bulky amidinate ligand [tBuC(NAr)2]–(= Piso, Ar = C6H3iPr2–2,6) allowed the synthesis and structural characterization of the chloro-functional complex (Piso)2CeCl (1). Complex 1 represents a rare example of an unsolvated bis(amidinato) lanthanide chloride. An X-ray diffraction study confirmed the presence of a pentacoordinate cerium(III) complex.

LGeOH (1; L = HC[(CMe)(NAr)]2, Ar = 2,6-iPr2C6H3) reacted with iron and manganese complexes to give LGe(OH)Fe(CO)4 (2) and LGe(OH)Mn(Cp)(CO)2 (3; Cp = cyclopentadienyl). Compounds 2 and 3 were characterized by IR, multinuclear NMR, EI-MS, and single-crystal X-ray diffraction.

Mixed-valent imido-bridged dinuclear titanium complexes, [Cp(2)Co][{(C(5)R(5))TiCl}(2)(μ-NAr)(2)] (R = H, Me; Ar = 3,5-(CF(3))(2)C(6)H(3)), were prepared by one-electron reduction of the corresponding [(C(5)R(5))TiCl](2)(μ-NAr)(2). One unpaired electron is delocalized in the central Ti(μ-NR)(2)Ti core as the first example of a fully delocalized mixed-valent imido-bridged [Ti(2)](7+) species.

The complex Ru(TPP)(NAr)(2) inserts a nitrene group into allylic and benzylic C-H bonds and is the key intermediate in the ruthenium porphyrin-catalyzed amination of hydrocarbons by aryl azides.

Summary The isoperoxidases of Funaria hygrometrica (Sibth.) wild type were analyzed in the phase of differentiation from chloronema to caulonema and compared with the mutant NAR-2. The mutant is not able to produce caulonema spontaneously; however, caulonema can be induced by exogenous auxin. Depending on the developmental stage, differences between the wild type (at the age of 8 and 14 days) and the mutant (at the age of 14 days) can be shown for isoenzyme patterns, and guaiacol-peroxidase and IAA-oxidaseperoxidase activities. In addition, cross reactions with 3 different polyclonal tobacco peroxidase antisera indicate that the degradation of free IAA in the mutant may be caused by basic IAA-oxidase-peroxxdasass acting in the cell wall during the process of polar auxin transport.

Reaction of ArNCO with syn-[MoO(mu-O)(S2CNR2)]2 or syn-[MoO(mu-NAr)(S2CNR2)]2 at 110 degrees C leads to the facile formation of bridging ureato complexes [Mo2(NAr)2(mu-NAr){mu-ArNC(O)NAr}(S2CNR2)2](Ar = Ph, p-tol; R = Me, Et, Pr), formed upon substitution of all oxo ligands and addition of a further equivalent of isocyanate across one of the bridging imido ligands. Related sulfido-bridged complexes [Mo2(NAr)2(mu-S){mu-ArNC(O)NAr}(S2CNR2)2] have been prepared from syn-[Mo2O2(mu-O)(mu-S)(S2CNR2)2]. When reactions with syn-[MoO(mu-NAr)(S2CNEt2)]2 were followed by NMR, intermediates were observed, being formulated as [Mo2O(NAr)(mu-NAr){mu-ArNC(O)NAr}(S2CNEt2)2], which at higher temperatures convert to the fully substituted products. A crystallographic study of [Mo2(N-p-tol)2(mu-S){mu-p-tolNC(O)N-p-tol}(S2CNPr2)2] reveals that the bridging ureato ligand is bound asymmetrically to the dimolybdenum centre-molybdenum-nitrogen bonds trans to the terminal imido ligands being significantly elongated with respect to those cis-a result of the trans-influence of the terminal imido ligands. This trans-influence also leads to a trans-effect, whereby the exchange of aryl isocyanates can occur in a regioselective manner. This is followed by NMR studies and confirmed by a crystallographic study of [Mo2(N-p-tol)2(mu-N-p-tol){mu-p-tolNC(O)NPh}(S2CNEt2)2]--the PhNCO occupying the site trans to the terminal imido ligands. Ureato complexes also react with PhNCS, initially forming [Mo2(NAr)2(mu-S){mu-ArNC(O)NAr}(S2CNR2)2], resulting from exchange of the bridging imido ligand for sulfur, together with small amounts of [Mo2(NAr)2(mu-S)(mu-S2)(S2CNEt2)2], containing bridging sulfide and disulfide ligands. The ureato complexes [Mo2(NAr)2(mu-S){mu-ArNC(O)NAr}(S2CNR2)2] react further with PhNCS to give [Mo2(NAr)2(mu-S)2(S2CNR2)2]n (n = 1, 2), which exist in a dimer-tetramer equilibrium. In order to confirm these results crystallographic studies have been carried out on [Mo2(N-p-tol)2(mu-S)(mu-S2)(S2CNEt2)2] and [Mo2(N-p-tol)2(mu-S)2(S2CNPr2)2]2.

Reaction of two equivalents of ArNCO (Ar = 2,6-iPr2C6H3) with [MoO2(edtc)2] affords the bisimido complex [Mo(NAr)2(edtc)2] shown by crystallography to contain two linear imido ligands; this is in contrast to the parent complex [Mo(NPh)2(edtc)2] previously shown to contain both linear and bent imido groups.

The reaction of 2 equiv of MeMgCl with Tc{sub 2}(NAr){sub 4}({mu}-NAr){sub 2} (Ar = 2,6-dimethylphenyl) results in displacement of an imido ligand and the formation of TcMe{sub 2}(NAr)({mu}-NAr){sub 2}Tc(NAr){sub 2}. Treatment of TcMe{sub 2-}(NAr)({mu}-NAr){sub 2}Tc(NAr){sub 2}({mu}-NAr){sub 2}Me{sub 4}. Single crystal X-ray determinations of these complexes confirmed the unprecedented substitution of an imido ligand by two methyl groups.

Previously isolated susceptible host mutants were used in a genetic and functional study of the resistance response of barley specified by resistance gene Mla12 to the fungal pathogen Erysiphe graminis f sp hordei. Mutant M66 represents a defective allele of Mla12, whereas M22, M82, and M100 represent mutations in loci unlinked to Mla12. Intermutant crosses of the latter three show that susceptibility in M82 and M100 is caused by allelic, recessive mutations that define the Nar-1 gene (necessary for Mla12 resistance gene 1), whereas the semidominant mutation in M22 defines a second unlinked locus, Nar-2. We show that both genes are required for resistance specified by Mlal2 in different genetic backgrounds of barley. Nar-1 maps on barley chromosome 2 within an ~6-centimorgan restriction fragment length polymorphism interval: this is 0.5 centimorgans from the anthocyanin pigmentation gene Ant2. Quantitative cytological analysis showed that functional alleles of Mla12, Nar-1, and Nar-2 are required for triggering a cell death reaction of attacked host cells at early stages during infection. Functional alleles of all three genes were also required for high-level transcript accumulation of barley defense-related genes that encode chitinase, peroxidase, and pathogenesis-related protein-1. The data support the hypothesis that host cell death and high-level accumulation of defense-related gene transcripts, which are under common control of Mla12, Nar-1, and Nar-2, are crucial events of race-specific resistance to powdery mildew.

Room temperature reaction of K2[Ru3(CO)11] with the molybdenum(VI) bis(imido) complexes Mo(NAr)2Cl2(dme) (Ar = C6H3X2-2,6; X = Me, Pri, Cl; dme = 1,2-dimethoxyethane) affords new high-low valent clusters Ru3(CO)12{Mo(NAr)2} which adopt a butterfly arrangement of metal centres with [Ru3(CO)12]2 acting as a ligand at a molybdenum(VI) centre.