Biosynthesis and Characterization of Poly (3-hydroxybutyrate-<Emphasis Type="Italic">co</Emphasis>-3-hydroxyvalerate-<Emphasis Type="Italic">co</Emphasis>-4-hydroxybutyrate) Terpolymer with Various Monomer Compositions by <Emphasis Type="Italic">Cupriavidus</Emphasis> sp. USMAA2-4

Poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-4-hydroxybutyrate) [P(3HB-co-3HV-co-4HB)] terpolymer was produced using Cupriavidus sp. USMAA2-4 via one-step cultivation process through combination of various carbon sources such as 1,4-butanediol or γ-butyrolactone with either 1-pentanol, valeric acid, or 1-propanol. Oleic acid was added to increase the biomass production. The composition of 3HV and 4HB monomers were greatly affected by the concentration of 1,4-butanediol and 1-pentanol. Terpolymers with 3HV and 4HB molar fractions ranging from 2 to 41 mol.% and 5 to 31 mol.%, respectively, were produced by varying the concentration of carbon precursors. The thermal and mechanical properties of the terpolymers containing different proportions of the constituent monomers were characterized using gel permeation chromatography (GPC), DSC, and tensile machine. GPC analysis showed that the molecular weights (M _w) of the terpolymer produced were within the range of 346 to 1,710 kDa. The monomer compositions of 3HV and 4HB were also found to have great influences on the thermal and mechanical properties of the terpolymer P(3HB-co-3HV-co-4HB) produced.     

Centrosymmetric [Mn2(CO)6(μ-thpymS)2] (thpymS = tetrahydropyrimidine-2-thionato) as a synthon to mixed-metal clusters

Reaction of [Mn₂(CO)₉(NCMe)] with tetrahydropyrimidine-2-thione (thpymSH) at 25 °C furnishes the mono- and dinuclear complexes [Mn(CO)₄(κ¹:η¹-SCNHC₃H₆NCO)] (2) and [Mn₂(CO)₆(μ-thpymS)₂] (1), respectively. Carbon-nitrogen coupling is observed in compound 2 resulting in the formation of κ¹:η¹-SCNHC₃H₆NCO ligand while compound 1 adopts a centrosymmetric structure. Reaction of 1 with [Os₃(CO)₁₀(NCMe)₂] at 80 °C affords the mixed Mn-Os cluster [MnOs₃(CO)₁₃(μ₃-thpymS)] (3) which possesses a butterfly skeleton of four metal atoms whereas with Ru₃(CO)₁₂ at 110 °C gives the mixed Mn-Ru complex [MnRu₃(CO)₁₄(μ₄-S)(κ¹:η¹-thpym)] (4). In contrast, treatment of 1 with Fe₃(CO)₁₂ at 80 °C furnishes two triiron complexes [Fe₃(CO)₉(μ₃-S)(μ₃-κ¹:η¹-C₄H₆N₂)] (5) and [Fe₃(CO)₈(μ₃-S)₂(η¹-C₄H₈N₂)] (6). The former also results from the direct reaction of thpymSH with Fe₃(CO)₁₂ and reacts with H₂S to afford 6. The molecular structures of all these new complexes have been determined by X-ray diffraction studies.     

Seven-coordinate anion complex with a tren-based urea: binding discrepancy of hydrogen sulfate in solid and solution states

Structural characterization of a hydrogen sulfate complex with a tren-based urea suggests that the anion is coordinated with six NH···O bonds (d(N···O) = 2.857 (3) to 3.092 (3) ?) and one OH···O bond (d(O···O) = 2.57 (2) ?) from three receptors; however, in solution the anion is bound within the pseudo-cavity of one receptor.     

Transition metal mediated construction of pyrrole ring on 2,3-dihydroquinolin-4(1H)-one: synthesis and pharmacological evaluation of novel tricyclic heteroarenes

A facile two-step method for the construction of fused pyrrole ring leading to 5-substituted 2,3-dihydro-1H-pyrrolo[3,2,1-ij]quinolin-1-ones via C-C followed by intramolecular C-N bond forming reaction is described. In vitro pharmacological evaluation and molecular modelling studies of some of the compounds synthesized are presented.     

Room-temperature combinatorial screening of cyclometallated iridium(III) complexes for a step towards molecular control of colour purity

A library of emission spectra of 90 bis-cyclometallated iridium complexes has been obtained using a simple combinatorial approach performed at room temperature. Trends in emission maxima are rationalized using Hammett parameters and invoking inter ligand energy transfer (ILET) processes. The screening approach allowed us to observe trends in the broadness of emission spectra opening the way for a rational approach to the engineering of the emission colour purity at a molecular level. Finally limitations to the screening strategy are discussed using a case study that involves two different monodentate ligands.     

Syntheses and reactivities of non-symmetrical "active ester" bi-dentate cross-linking reagents having a phthalimidoyl and acid chloride, 2-benzothiazole, or 1-benzotriazole group

We have newly synthesized the non-symmetrical "phthalimidoyl active ester" bi-dentate cross-linking reagents having an acid chloride, 2-benzothiazole, or 1-benzotriazole group (i.e., 9, 15, and 16) on the basis of the reactivity study of the "active ester" model compounds, 11-14, toward the various nucleophiles and examined their reaction selectivity towards the same nucleophiles. Then, we applied for the modification of cholesterol at the more reactive site of the bi-dentate linkers to give 3β-cholesteryl 4-(phthalimidoyloxycarbonyl)butyrate (39), and the subsequent reaction of 39 with several amines, such as benzylamine, 4-chlorobenzylamine, 2-phenylethylamine, L-phenylalanine methyl ester, or diphenylalanine benzyl ester as a protein model of the cholesterol antigen.     

A novel metal-free panchromatic TiO2 sensitizer based on a phenylenevinylene-conjugated unit and an indoline derivative for highly efficient dye-sensitized solar cells

A novel donor-π-spacer-acceptor type organic dye (AK01) bearing a phenylenevinylene-conjugated system and a derivative of indoline donor was synthesized for dye-sensitized solar cells. AK01 showed panchromatic TiO(2) sensitization with high overall conversion efficiency of 6.2% under AM 1.5 illumination (100 mW cm(-2)).     

Synthetic applications of 3H‐1,2,4‐dithiazoles: Structure and reactivity studies

Synthetic applications of 3H‐1,2,4‐dithiazoles have been studied extensively. The facile synthesis of hitherto unknown 3H‐1,2,4‐dithiazole S‐oxides was realized by the mCPBA oxidation of 3H‐1,2,4‐dithiazoles. The structural information of the 1,2,4‐dichalcogenazole ring system was revealed by the ORTEP analysis of 3‐tert‐butyl‐5‐4‐chloro‐phenyl‐3H‐1,2,4‐dithiazole S‐oxide. The reactivities of 3H‐1,2,4‐dithiazoles are also discussed. © 2011 Wiley Periodicals, Inc. Heteroatom Chem 23:154–159, 2012; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.20764     

Study of redox behavior of Cd(II) and interaction of Cd(II) with proline in the aqueous medium using cyclic voltammetry

The redox behavior of Cd(II) and the interaction of Cd(II) with cyclic amino acid, proline, have been studied in 0.1 M KCl, 0.1 M NaClO₄ and acetate buffer of different pH. The CVs were recorded at glassy carbon electrode within the potential window 200 and ?1500 mV. The reference and counter electrode used were Ag/AgCl and Pt wire, respectively. The cyclic voltammograms show one pair of cathodic and anodic peaks for the Cd(II)/Cd(0) system indicating the involvement of two electron transfer processes. The peak potential shift and charge transfer rate constant (k_f) values strongly support the interaction between metal and ligand. The higher value of peak current ratio and peak potential separation (ΔE) indicate that the systems are quasireversible. The effect of supporting electrolyte and concentration of electro active species on the interaction were also studied.