Copper Phthalocyanine Improving Nonaqueous Catalysis of Pseudomonas cepacia Lipase for Ester Synthesis.

The nonaqueous catalysis of lipases is significant for synthesis of high pure esters, but they usually behave low catalytic activity due to denaturation and aggregation of enzyme protein in organic phases. To improve the nonaqueous catalysis, the inexpensive copper phthalocyanine was taken as a new carrier on which Pseudomonas cepacia lipase was immobilized by physical absorption, and used for synthesis of hexyl acetate, an important flavor, via transesterification of hexanol and vinyl acetate. Results showed that the desired loading was 10-mg lipase immobilized on 10-mg copper phthalocyanine powder. When the immobilized lipase was employed in the reaction system consisted of 1.5-mL hexanol and 1.5-mL vinyl acetate at 37°C and 160 rpm, the conversion was fivefolds of that catalyzed by native lipase after 1 h, and reached 99.0% after 8 h. In six times of 8-h reuses, the immobilized lipase behaved an activity attenuation rate 1.22% h-1, lower than 1.77% h-1 of native lipase, which meant that the immobilized lipase was more stable. Even at the room temperature and the static state without shaking or stirring, the immobilized lipase still brought conversion 42.8% after 10 h and the native lipase gave 20.1%. Obviously, the immobilized lipase is an available biocatalyst in organic phase and has great potential in food industry.

Copper Phthalocyanine Improving Nonaqueous Catalysis of Pseudomonas cepacia Lipase for Ester Synthesis.

The nonaqueous catalysis of lipases is significant for synthesis of high pure esters, but they usually behave low catalytic activity due to denaturation and aggregation of enzyme protein in organic phases. To improve the nonaqueous catalysis, the inexpensive copper phthalocyanine was taken as a new carrier on which Pseudomonas cepacia lipase was immobilized by physical absorption, and used for synthesis of hexyl acetate, an important flavor, via transesterification of hexanol and vinyl acetate. Results showed that the desired loading was 10 mg lipase immobilized on 10 mg copper phthalocyanine powder. When the immobilized lipase was employed in the reaction system consisted of 1.5 mL hexanol and 1.5 mL vinyl acetate at 37℃ and 160 rpm, the conversion was five fold of that catalyzed by native lipase after 1 h, and reached 99.0% after 8 h. Undergoing six times of 8-h reuses, the immobilized lipase had an activity attenuation rate 1.22% h- 1, lower than 1.77% h- 1 of native lipase, which meant that the immobilized lipase was more stable. Even at the room temperature and the static state without shaking or stirring, the immobilized lipase could bring conversion 42.8% after 10 h and the native lipase gave 20.1%. Obviously, the immobilized lipase is an available biocatalyst in organic phase and has great potential in food industry.

Rice straw enhancing catalysis of Pseudomonas fluorescens lipase for synthesis of citronellyl acetate.

Citronellyl acetate as an important flavor, can be effectively synthesized by lipase catalysis in nonaqueous system. But lipases usually behave low catalytic activity due to aggregation and denaturation of them in organic phase. To enhance the nonaqueous catalysis, based on the mechanism of lipases activated at water/oil (organic phase) interface, the inexpensive race straw was processed into powder and filaments on which Pseudomonas fluorescens lipase was immobilized by physical adsorption, used for synthesis of citronellyl acetate via transesterification of citronellol and vinyl acetate. Results showed that the desired loading was 10 mg lipase immobilized on 30 mg rice straw filaments or 25 mg rice straw powder. When the two immobilized lipases were employed in the reaction system consisted of 1-mL citronellol and 2-mL vinyl acetate at 37 â„ƒ and 160 rpm, the conversions all reached 99.8% after 12 h. Under the reaction condition, the conversion catalyzed by 10 mg native lipase was 85.1%. Undergoing six times of 8-h reuses in the organic system, the filament and power immobilized lipases had weak activity attenuation rates 0.36 and 0.32% h-1, lower than 1.52% h-1 of native lipase. Even at the room temperature and the static state without shaking and stirring, the rice straw filaments immobilized lipase could brought conversion 62.9% after 10 h but the native lipase only gave 37.0%. Obviously, the rice straw, especially its filaments, is an inexpensive and available natural material to prepare immobilized lipase with desired catalysis in organic phase, meant significant potential in flavor industry.

A series of asymmetrical phthalocyanines: synthesis and near infrared properties.

We report here the preparation of asymmetrical phthalocyanine dimers 1a-3a, which are endowed with novel charge transfer bands at 1,151-1,154 nm and strong NIR luminescences at 840-860 nm and 1,600-1,650 nm. Through H-bonding interaction, 1a-3a are inclined to self-assemble into hexrod nanotubes at the interface of CHCl3 and CH3H. Our results provide further insights into the interaction in molecular dimers, and suggest that 1a-3a have potential application in magnets and supramolecular architectures.

Enhanced activity and enantioselectivity of a hyperthermophilic esterase from archaeon Aeropyrum pernix K1 by acetone treatment.

To improve the activity and enantioselectivity of hyperthermophilic archaeon Aeropyrum pernix K1 esterase (APE1547) and its mutants, they were purified by acetone-treated method. It was found that the acetone treatment not only caused APE1547 and its mutants to display higher activity and enantioselectivity but also saved more than 90% of time spent in purifying them by Ni-chelating column. In hydrolysis of p-nitrophenyl caprylate, the acetone-treated APE1547 and mutant A containing the following substitutions R11G, L36P, V225A, I551L, and A564T showed 5.7- and 6.9-fold active increase, respectively. In the resolution of 2-octanol acetate, the acetone-treated mutant A had a 9-fold enantioselective increase relative to that purified by Ni-chelating column. In addition, the impact of pH, temperature, and chemical reagents on activity of APE1547 and mutant A was discussed in this paper.

Bis(2-methyl-1H-imidazole-κN)silver(I) nitrate dihydrate.

The Ag(I) atom in the salt, [Ag(C(4)H(6)N(2))(2)]NO(3)·2H(2)O, shows a nearly linear coordination [N-Ag-N = 178.26 (7)°]. The cation, anion and water mol-ecules are linked by N-H⋯O and O-H⋯O hydrogen bonds into a layer motif extending parallel to (101).

Poly[aqua-bis(µ(4)-naphthalene-1,4-di-carboxyl-ato)(1,10-phenanthroline-5,6-dione)dimanganese(II)].

The three-dimensional coordination polymer, [Mn(2)(C(12)H(6)O(4))(2)(C(12)H(6)N(2)O(2))(H(2)O)](n), features a water-coord-inated Mn(II) ion and an N-heterocycle-chelated Mn(II) ion, both in six-coordinate octa-hedral geometries. Of the two rigid dianions, one is bonded to four Mn(II) ions, with each of the O atoms being connected to a different metal ion. The other dianion uses one carboxyl-ate group to chelate to one Mn(II) ion and its other carboxyl-ate group to bind to two Mn(II) ions.

catena-Poly[[(1,10-phenanthroline-5,6-dione-κN,N')lead(II)]-µ-terephthalato-κO:O].

The Pb(II) atom in the polymeric title compound, [Pb(C(8)H(4)O(4))(C(12)H(6)N(2)O(2))](n), is chelated by the N-heterocycle, and adjacent atoms are bridged by rigid terephthalate dianions into a linear chain. The Pb(II) atom is stereochemically active in a ψ-square-pyramidal coordination geometry in which the lone-pair electrons occupy a basal site. When three other weaker Pb⋯O inter-actions are considered, the geometry is a ψ-dodeca-hedron.

Tuning J-type dimers of non-peripherally substituted zinc tetra-4-tert-butylphenophthalocyanine.

It was found, by UV-vis and TOF-MS, that the head-to-tail dimers of non-peripherally substituted zinc tetra-4-tert-butylphenophthalocyanine are inclined to form in non-coordinated solvent, e.g. chloroform and especially in dilute solution under 1.25 x 10(-6)mol/mL. The aforementioned dimers in solution can be tuned by altering concentration or adding coordinated solvent, e.g. methanol, which might be further improved to a practical strategy for preparation of J-aggregates in the future.

The control of phthalocyanine properties through nitro-group electronic effect.

The UV-vis spectra of peripherally substituted tetranitrometallophthalocyanines (TNMPcs) 1a-1d and non-peripherally substituted TNMPcs 2a-2d were investigated. In comparison of 1a with 2a, there is the only difference in the substitution position of nitro-groups. The structural diversity of 1a and 2a resulted in different electronic effects of nitro-group on Pc rings, which caused them have two kinds of Q bands. The Q band in the UV-vis spectra of 1a-1d was split into two peaks, which were obviously influenced by temperature, while no split was observed in the Q band of 2a-2d. We can draw a conclusion that tuning nitro-group electronic effect is an important approach for controlling the properties of Pcs.

[5C + 1N] annulation: a novel synthetic strategy for functionalized 2,3-dihydro-4-pyridones.

A novel and facile route to functionalized mono/bicyclic 2,3-dihydro-4-pyridones has been developed via formal [5C + 1N] annulation of readily available alpha-alkenoyl ketene-(S,S)-acetals with various aliphatic primary amines.