Podophyllotoxin from suspension culture of Linum album

Callus and suspension cultures of Linum album as an Iranian species for synthesis of aryltetralin lactone were used. After cultivation period; we can isolate and characterize podophyllotoxin as glycosides compounds. Maximal product yield is 0.5% of the dry weight in dark grown cultures.     

Competition between chalcogen bond and halogen bond interactions in YOX<Subscript>4</Subscript>:NH<Subscript>3</Subscript> (Y = S,Se; X = F,Cl, Br) complexes: An ab initio investigation

Using ab initio calculations, the geometries, interaction energies and bonding properties of chalcogen bond and halogen bond interactions between YOX₄ (Y = S, Se; X = F, Cl, Br) and NH₃ molecules are studied. These binary complexes are formed through the interaction of a positive electrostatic potential region (σ-hole) on the YOX₄ with the negative region in the NH₃. The ab initio calculations are carried out at the MP2/aug-cc-pVTZ level, through analysis of molecular electrostatic potentials, quantum theory of atoms in molecules and natural bond orbital methods. Our results indicate that even though the chalcogen and halogen bonds are mainly dominated by electrostatic effects, but the polarization and dispersion effects also make important contributions to the total interaction energy of these complexes. The examination of interaction energies suggests that the chalcogen bond is always favored over the halogen bond for all of the binary YOX₄:NH₃ complexes.     

A Photoclick-Based High-Throughput Screening for the Directed Evolution of Decarboxylase OleT

Enzymatic oxidative decarboxylation is an up-and-coming reaction yet lacking efficient screening methods for the directed evolution of decarboxylases. Here, we describe a simple photoclick assay for the detection of decarboxylation products and its application in a proof-of-principle directed evolution study on the decarboxylase OleT. The assay was compatible with two frequently used OleT operation modes (directly using hydrogen peroxide as the enzyme's co-substrate or using a reductase partner) and the screening of saturation mutagenesis libraries identified two enzyme variants shifting the enzyme's substrate preference from long chain fatty acids toward styrene derivatives. Overall, this photoclick assay holds promise to speed-up the directed evolution of OleT and other decarboxylases.     

Effects of Solvent and Reaction Time in Sonochemical Synthesis of Cadmium(II) Compounds and Use them as Template for Synthesis of Cadmium(II) Oxide Nano Structures

Abstract . A cadmium(II) zero-dimensional supramolecular compound [Cd(L)₂(I)₂] ( 1 ), {L = 2-picolylamine}, was fabricated by branch tube and sonochemical irradiation techniques. Regardless of the method utilized, the same crystallographic structure is obtained for the complex. To investigate the effects of reaction time and solvent on the creation of [Cd(L)₂(I)₂] ( 1 ) supramolecule compound, certain tests were designed and four specimens of 1 were fabricated through sonochemical process. Less reaction time led to the creation of smaller particles with mixed morphologies. To prepare cadmium(II) oxide micro-crystals via calcination, four samples were utilized as new precursors. Micro- and nano-sphere of cadmium(II) oxide could be fabricated from 1. The morphology and structure of micro- and nano-crystals were identified by using Scanning Electron Microscopy (SEM), IR spectroscopy, and X-ray powder diffraction (XRD).     

Organosoluble and thermally stable polyimides derived from a new diamine containing bulky-flexible triaryl pyridine pendent group

A novel kind of aromatic diamine,N-(4-(4-(2,6-diphenyl pyridine-4-yl)phenoxy)phenyl)-3,5-diaminobezamide (DPDAB),was synthesized via aromatic nucleophilic substitution of 3,5-dinitrobenzoylchloride with 4-(4-(2,6- diphenylpyridine-4-yl)phenoxy)aniline(DPPA),followed by palladium-catalyzed hydrazine reduction.This monomer was used to prepare polyimides(PIs)based on reaction with several commerically avaiable tetracarboxylic dianhydrides such as pyromellatic dianhydride(PMDA),benzophenone tetracarboxylic acide dianhydride(BTDA)and bicycle[2.2.2]oct-7-enc- 2,3,5,6-tetracarboxylic dianhydride(BCDA).These PIs had inherent viscosity in the range of 0.34-0.76 dL/g and showed good solubility in various aprotic polar solvents.The glass-transition tempratures(T_gs)of the PIs were in the range of 184-302℃,and showed high thermal stability with 10%weight loss in the temperature range of 360-500℃under nitrogen atmosphere.     

Design of a coupled bioluminescent assay for a recombinant pyruvate kinase from a thermophilic Geobacillus

A simple and rapid method using coupled bioluminescent assay was developed to determine level of ADP. ADP is involved in many biological reactions and ADP assay can be used for assaying some reactions universally by monitoring ADP formation or depletion. ADP analysis involves incubation of ADP or extracts containing ADP with pyruvate kinase (PK) and PEP. The ATP formed by this reaction is determined by measuring the intensity of the initial light flash produced when luciferin-luciferase preparation injected into the reaction mixture. In regard to the main role of the PK in this assay, the gene of PK from a Geobacillus species has been cloned in expression vector pET28a (+), sequenced and overexpressed in Escherichia coli. Recombinant protein was purified using Ni-NTA column and then the purified PK was used in a coupled bioluminescent assay for ADP measurement. Kinetic properties of PK are determined according to a bioluminescent assay using firefly luciferase.     

Synthesis and characterization of polyamides derived from (4-(4-(2, 6-diphenylpyridin-4yl)phenoxy)phenyl)-3, 5-diaminobezamide

New types of polyamides containing pendent triaryl pyridine groups were successfully synthesized by direct polycondensation of a symmetry diamine,（4-（4-（2,6-diphenylpyridin-4yl）phenoxy）phenyl）-3,5-diaminobezamide（DPDAB）, and various aromatic and aliphatic dicarboxylic diacids in NMP using triphenyl phosphate（TPP） and pyridine as catalyst. The diamine and all the prepared polyamides were fully characterized by using FT-IR,¹H-NMR,UV-Vis spectroscopy, fluorimetry and elemental analysis.The inherent viscosity of polyamides ranged from 0.45 dL/g to 0.68 dL/g.All the polymers exhibited solubility in common polar aprotic solvents such as NMP,DMAc,DMF,DMSO,pyridine,HMPA,and even in less polar solvents such as THF and m-cresol at room temperature.Thermal properties of polyamides were evaluated by means of DSC,DMTA and TGA.These polymers showed glass transition temperatures（T_g） in the range of 138-210℃. Their initial decomposition temperature（T_i） varied from 265℃to 310℃under N₂.The dilute solution（0.2 g/dL） of polyamides in DMF exhibited fluorescence emission withλ_max in the range of 470-550 nm.     

Synthese und Kristallstruktur des gemischt‐valenten Komplexes [Sn2I3(NPPh3)3]

Synthesis and Crystal Structure of the Mixed Valent Complex [Sn₂I₃(NPPh₃)₃] The mixed valent phosphoraneiminato complex [Sn₂I₃(NPPh₃)₃] ( 1 ) was prepared by the reaction of the tin(II) complex [SnI(NPPh₃)]₂ with sodium in tetrahydrofuran. 1 crystallizes with two formula units of THF to form yellow, moisture sensitive single crystals, which were characterized by a crystal structure determination. 1 · 2 THF: Space group P2₁/c, Z = 4, lattice dimensions at –80 °C: a = 1964.5(2), b = 1766.0(2), c = 2058.6(2) pm; β = 118.33(1)°, R = 0.052. 1 forms dimeric molecules in which the tin atoms are linked by two nitrogen atoms of two (NPPh₃^–) groups to form a planar Sn₂N₂ four‐membered ring. The Sn^IV atom is additionally coordinated by a terminal iodine atom and by a terminal (NPPh₃^–) group, whereas the Sn^II atom is additionally coordinated by two iodine atoms forming a ψ trigonal‐bipyramidal surrounding.     

Gliclazide as novel carrier in construction of PVC-based La(III)-selective membrane sensor

A PVC-based sensor for La³⁺ ions based on N-[hexahydrocyclopentapyrol-2((1H)yl)amino]carbonyl]-4-methyl benzene sulfonamide (gliclazide) as a novel carrier was prepared. The electrode exhibits a Nernstian response for La³⁺ over a wide concentration range (1.0×10⁻¹-1.0×10⁻⁶ M) with a slope of 20.1 mV per decade. The limit of detection is 8.0×10⁻⁷ M. The sensor has a very short response time (<15 s) and a useful working pH range of 4.0-8.0. The proposed membrane sensor shows excellent discriminating ability towards La³⁺ ions with regard to several alkali, alkaline earth, transition and heavy metal ions. The electrode was successfully applied for determination of La³⁺ in binary mixtures.