Carbon monoxide :acceptor oxidoreductase from Pseudomonas thermocarboxydovorans strain C2 and its use in a carbon monoxide sensor

The carbon monoxide:acceptor oxidoreductase from autotrophically-grown Pseudomonas thermocarboxydovorans strain C2 was purified to 95% homogeneity and found to contain fiavin, iron, acid-labile sulphide and possibly molybdenum; its molecular weight was 2.7 × 10⁵. The enzyme catalyzed the oxidation of CO to CO₂ with various electron acceptors including phenazine ethosulphate, methylene blue, hexacyanoferrate(III) and ferrocene derivatives (ferrocene monocarboxylic acid, 1,1′dimethylferrocene and horse heart cytochrome C) but not viologen dyes, NAD(P) and oxygen. The optimum pH and temperature for enzyme activity in the in vitro assay were 7.5 and 80°C, respectively. Carbon monoxide is the only known electron donor (apparent K_m 5 × 10^?7 M) and acetylene, cyanide, 8-quinolinol and sulphydryl reagents inhibited the enzyme. Second-order homogeneous rate constants for the reaction between the reduced enzyme and either cytochrome C (3.0 × 10⁴ l mol^?1 s^?1) or the ferricinium ion of ferrocene monocarboxylic acid (4.0 × 10⁵ l mol^?1 s^?1) were calculated by using cyclic voltammetry. The latter reaction was exploited by incorporating 1,1′-dimethylferrocene in a carbon electrode and retaining carbon monoxide oxidoreductase behind a membrane at the surface. The probe gave a linear current response to aqueous concentrations of carbon monoxide up to 65 μM and achieved a steady current in < 15 s. A similar configuration was used to detect gaseous carbon monoxide. With a fuel cell mode, 20 nmol could be detected.     

A green synthesis of chemiluminescent N-sulfopropyl acridinium esters in ionic liquids without using the carcinogen 1,3-propane sultone

Chemiluminescent acridinium dimethylphenyl esters containing hydrophilic N-sulfopropyl groups in the acridinium ring are used as labels in automated immunoassays for clinical diagnostics. Introduction of the N-sulfopropyl group in these labels is normally accomplished by N-alkylation of the corresponding, nonchemiluminescent acridine ester precursors with the toxic carcinogen 1,3-propane sultone. In the current study, we report that sodium 3-bromopropane sulfonate in ionic liquids (ILs) is a benign alternative to 1,3-propane sultone for introducing the N-sulfopropyl group in chemiluminescent acridinium ester labels. The sultone reagent can be eliminated in the synthesis of N-sulfopropyl acridinium dimethylphenyl ester labels by taking advantage of the increased reactivity of acridan esters toward nontoxic sodium 3-bromopropane sulfonate in [BMIM][BF₄]. Sodium 3-bromopropane sulfonate in ILs is also potentially a nontoxic alternative to 1,3-propane sultone for introducing the water-soluble, three-carbon sulfobetaine moiety in other molecules as well.     

New ferrocenyl derivative with controllable aggregation-induced emission (AIE) characteristics

A novel molecular switch, 7-(N,N-diethylamino)-2-oxo-2H-chromen-4-yl ferrocene carboxylate (FCC), was synthesized and fully characterized by ¹H NMR, ¹³C NMR, and HRMS. Taking advantage of the properties of ferrocene as an electron donor active unit and the coumarin as a fluorescent unit, the dyad FCC shows a fast and reversible redox-switchable fluorescence emission. In sharp contrast to most photoluminescent chromophores, FCC has a unique enhanced emission through aggregation. The change of electrochemical signals (CV and DPV) indicated that the ferrocene (F_c) unit of FCC could form inclusion complex with Me-β-cyclodextrin (CD). This inclusion complex could further weaken the aggregation-induced emission (AIE) effect remarkably. This advance paves the way to introduce AIE property into molecular devices applications.     

Luminescent Chiral Exciplexes with Sky-Blue and Green Circularly Polarized-Thermally Activated Delayed Fluorescence

Luminescent exciplexes based on a chiral electron donor and achiral acceptors are reported as a new approach to design circularly polarized (CP) and thermally activated delayed fluorescence (TADF) emitters. This strategy results in rather high CP luminescence (CPL) values with g_lum up to 7×10⁻³, one order of magnitude higher in comparison to the CPL signal recorded for the chiral donor alone (g_lum ∼7×10⁻⁴). This increase occurs concomitantly with a CPL sign inversion, as a result of the strong charge-transfer emission character, as experimentally and theoretically rationalized by using a covalent chiral donor-acceptor model. Interestingly, blue, green-yellow and red chiral luminescent exciplexes can be obtained by modifying with the electron accepting character of the achiral unit while keeping the same chiral donor unit. These results bring new (inter)molecular guidelines to obtain simply and efficiently multi-color CP-TADF emitters.     

Precise Control of Intramolecular Charge‐Transport: The Interplay of Distance and Conformational Effects

A new series of donor–bridge–acceptor (D–B–A) compounds consisting of π‐conjugated oligofluorene (oFL) bridges between a ferrocene (Fc) electron‐donor and a fullerene (C₆₀) electron‐acceptor have been synthesized. In addition to varying the length of the bridge (i.e., mono‐ and bi‐fluorene derivatives), four different ways of linking ferrocene to the bridge have been examined. The Fc moiety is linked to oFL: 1) directly without any spacer, 2) by an ethynyl linkage, 3) by a vinylene linkage, and 4) by a p‐phenylene unit. The electronic interactions between the electroactive species have been characterized by cyclic voltammetry, absorption, fluorescence, and transient absorption spectroscopy in combination with quantum chemical calculations. The calculations reveal exceptionally close energy‐matching between the Fc and the oFL units, which results in strong electronic‐coupling. Hence, intramolecular charge‐transfer may easily occur upon exciting either the oFLs or Fcs. Photoexcitation of Fc–oFL–C₆₀ conjugates results in transient radical‐ion‐pair states. The mode of linkage of the Fc and FL bridge has a profound effect on the photophysical properties. Whereas intramolecular charge‐separation is found to occur rather independently of the distance, the linker between Fc and oFL acts (at least in oFL) as a bottleneck and significantly impacts the intramolecular charge‐separation rates, resulting in beta values between β_CS 0.08 and 0.19 Å^?1. In contrast, charge recombination depends strongly on the electron‐donor–acceptor distance, but not at all on the linker. A value of β_CR (0.35±0.01 Å^?1) was found for all the systems studied. Oligofluorenes prove, therefore, to be excellent bridges for probing how small structural variations affect charge transport in D–B–A systems.     

HYDROXYALKANESULFONYL CHLORIDES FROM CHLORINATION OF HYDROXYALKANESULFINATE SALTS IN A NONPOLAR MEDIUM: 3-HYDROXY-1-PROPANESULFONYL AND 4-HYDROXY-1-BUTANESULFONYL CHLORIDES

Abstract

3-Hydroxy-1-propanesulfonyl chloride (1b) was obtained for the first time (admixed with 10% of propane sultone, 2b) by chlorination of a dichloromethane suspension of sodium 3-hydroxy-1-propanesulfinate (3b). 4-Hydroxy-1-butanesulfonyl chloride (1c) containing 13% butane sultone (2c) was prepared similarly from 3c. The cyclizations of 1b and 1c in CDCl₃ containing 1-butanol (0.9 M) showed first order rate constants of 1.4 × 10^?4 and 6.4 × 10^?5 s^?1, corresponding to effective concentrations of 4.5 × 10² and 2.1 × 10² M, respectively. Reaction of triethylamine in ethanol-d (a) with 1b gave exclusively the undeuterated sultone (2b), evidently by a direct cyclization, and (b) with 1c produced mainly ethyl 4-hydroxy-1-butanesulfonate largely monodeuterated at the α-position, and presumably formed by way of the sulfene (6c).     

SYNTHESES OF BRANCHED POLY(ETHER KETONE)S WITH PENDANT FUNCTIONAL GROUPS BASED ON 1,1,1-TRIS(4-HYDROXYPHENYL)ETHANE

ABSTRACT

1,1,1-Tris(4-hydroxyphenyl)ethane, THPE, was silylated with chlorotrimethylsilane and the silylated THPE was polycondensed with 1,4-bis(4-fluorobenzoyl)benzene, BFBB, in dry N-methylpyrrolidone. The resulting poly(ether ketone) had a moderate molecular weight and contained a significant fraction of cyclic oligomers and polymers. The pendant trimethylsiloxy group allowed an in situ alkylation with chloropropionitrile, allylbromide, 3,4-dichlorobenzyl chloride, 4-nitrobenzyl bromide, 1,3-propane sultone and 1,4-butane sultone. The latter alkylating agents yielded poly(ether ketone)s having pendant sulfonic acid groups. Further functional groups were introduced by acylation of the pendant free OH-group (resulting from the hydrolysis of the Me₃SiO group) with acetic anhydride, methacrylic anhydride, cinnamoyl chloride and undecenoyl chloride.     

Mechanism and Linear Free Energy Relationships in Michael‐Type Addition of 4‐Substituted Anilines to Activated Olefin in Acetonitrile

Kinetic studies for the Michael‐type reactions of ethyl‐3‐(4′‐N,N‐dimethylaminophenyl)‐2‐(nonafluorobutane)sulfonylpro‐penoate 1 with 4‐X‐substituted anilines 2a–e (X = OCH₃, CH₃, H, F, and Cl) have been investigated in acetonitrile at 20°C. A quadratic dependence of the pseudo–first‐order rate constants (k_obsd) versus [ 2a–e ] has been observed and has been interpreted in terms of a dimer nucleophile mechanism. The finding of a relatively large negative ρ value (?3.09) for the Hammett plot suggests that the intermediate ( I^± ) is highly zwitterionic in nature. A linear correlation (r² = 0.9989) between the Hammett's substituent constants σ and nucleophilicity parameters N of 4‐X‐substituted anilines in acetonitrile has been observed. The electrophilicity parameters E of the olefin 1 is evaluated, using the correlations σ versus N and log k versus σ and compared with the electrophilicities of analogously Michael acceptors.     

Synthesis and characterization of a new phenanthrenequinoxaline‐based polymer for organic solar cells

Two donor–acceptor (D‐A) conjugated polymers, PQx and PphQx, composed of alkylthienyl‐substituted benzo[1,2‐b:4,5‐b']dithiophene (BDTT) as the electron donor and the new electron acceptors quinoxaline (Qx) or phenanthrenequinoxaline (phQx), were synthesized with Stille cross‐coupling reactions. The number‐averaged molecular weights (M_n) of PQx and PphQx were found to be 25.1 and 23.2 kDa, respectively, with a dispersity of 2.6. The band‐gap energies of PQx and PphQx are 1.82 and 1.75 eV, respectively. These results indicate that, because phQx units have highly planar structures, their inclusion in D‐A polymers will be a very effective method for increasing the polymers' effective conjugation lengths. The hole mobilities of PQx and PphQx were determined to be 5.0 × 10^?5 and 2.2 × 10^?4 cm² V^?1 s^?1, respectively. A polymer solar cell device prepared with PphQx as the active layer was found to exhibit a power conversion efficiency (PCE) of 5.03%; thus, the introduction of phQx units enhanced both the short circuit current density and PCE of the device. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 2804–2810     

Solvent effects on the electron donor acceptor complex properties of ferrocene and tetranitromethane

Summary Spectral investigations in the 350–800 nm range of ferrocene (FcH) and tetranitromethane [C(NO₂)₄] solutions in cyclohexane and carbon tetrachloride at concentration-constant (FcH) and variable (tetranitromethane) were made. The electron donor acceptor (EDA) complex of ferrocene and tetranitromethane and its dissociation to the ferricenium cation (FcH⁺) were studied as a function of the solvent, the initial C(NO₂)₄ concentration and reaction time.     

Synthesis of multi-hydroxyl and sulfonyl dual-functionalized room temperature ionic liquids

Starting from the hydroxylamine (dimethyl amino ethanol, triethanolamine) and 1,3-propane sultone, a series of hydroxyl and sulfonyl dual-functionalized zwitterionic salts and corresponding acidic room temperature ionic liquids have been synthesized. The hydroxyl groups of the synthesized substances were confirmed by the 1H NMR measurement. These zwitterionic salts and ionic liquids may be used for synthesizing other functionalized ionic liquids or ionic liquid-polymer (polyelectrolyte).     

Ultrafast Photoinduced Energy and Electron Transfer in Multi‐Modular Donor–Acceptor Conjugates

New multi‐modular donor–acceptor conjugates featuring zinc porphyrin (ZnP), catechol‐chelated boron dipyrrin (BDP), triphenylamine (TPA) and fullerene (C₆₀), or naphthalenediimide (NDI) have been newly designed and synthesized as photosynthetic antenna and reaction‐center mimics. The X‐ray structure of triphenylamine‐BDP is also reported. The wide‐band capturing polyad revealed ultrafast energy‐transfer (k_ENT=1.0×10¹² s^?1) from the singlet excited BDP to the covalently linked ZnP owing to close proximity and favorable orientation of the entities. Introducing either fullerene or naphthalenediimide electron acceptors to the TPA‐BDP‐ZnP triad through metal–ligand axial coordination resulted in electron donor–acceptor polyads whose structures were revealed by spectroscopic, electrochemical and computational studies. Excitation of the electron donor, zinc porphyrin resulted in rapid electron‐transfer to coordinated fullerene or naphthalenediimide yielding charge separated ion‐pair species. The measured electron transfer rate constants from femtosecond transient spectral technique in non‐polar toluene were in the range of 5.0×10⁹–3.5×10¹⁰ s^?1. Stabilization of the charge‐separated state in these multi‐modular donor–acceptor polyads is also observed to certain level.     

基于柔性四羧酸的三个一维/二维/三维Zn(Ⅱ)/Co(Ⅱ)配合物的晶体结构及荧光性质

通过水热/溶剂热合成的方法制备了3个 Zn(Ⅱ)/Co(Ⅱ)配合物{[Zn(H2L)(H2O)3]·H2O·0.5H4L}n(1)、{[Co(L0.5(4,4'-bpy)]·0.5H2O}n(2)和{[Co(L)0.5(pbmb)(H2O)]·H2O}n(3)(H4L=5,5'-(hexane-1,6-diyl)-bi...     

Lutetium bisphthalocyanine: the first molecular semiconductor. Conduction properties of thin films of p- and n-doped materials

Thin films of bisphthalocyaninatolutetium derivatives (Pc₂Lu) have been doped using a co-sublimation technique with an electron acceptor (dichlorodicyanoquinodimethane, DDQ) and an electron donor (tetraphenyldithiapyranylidene, DIPSΦ₄). The conduction properties of Pc₂Lu and of p- and n-type doped materials have been determined and correlated with the optical characteristics of the films. Pc₂Lu is the first molecular semiconductor that satisfies the following three criteria: (i) it is a molecular material, (ii) its intrinsic conductivity is in the range 10⁻⁶−10⁻¹Ω⁻¹cm⁻¹, (iii) it can be doped with both electron acceptors and electron donors.     

Complexation and extraction of non-ferrous metals by calix[n]arene phosphine oxides

The extraction of non-ferrous metal (M²⁺) nitrates by the calix[4,6]arenes (L), bearing four or six phosphine oxide donor groups at the upper or at the lower rim, was quantitatively described in the form of [M_n(NO₃)_2nL] (n = 1, 2) complexes. The extraction constants (Zn²⁺ > Cu²⁺ > Co²⁺ > Ni²⁺) for the both types of L coincide with Irving-Williams sequence. Calix[4]arenes, phosphorylated at the lower (narrow) rim, provide better stability of ML complexes because of the best spatial fitting of M²⁺ by the donor groups. For the upper (wide) rim phosphorylated calix[4]arenes M₂L and ML₂ complexes are more stable. Unusual zwitterionic [Co₂(NO₃)₄L] complex of the lower rim tetraphosphorylated calix[4]arene 1 was determined by X-ray structural analysis.     

Synthesis and applications of low‐bandgap conjugated polymers containing phenothiazine donor and various benzodiazole acceptors for polymer solar cells

A series of soluble donor‐acceptor conjugated polymers comprising of phenothiazine donor and various benzodiazole acceptors (i.e., benzothiadiazole, benzoselenodiazole, and benzoxadiazole) sandwiched between hexyl‐thiophene linkers were designed, synthesized, and used for the fabrication of polymer solar cells (PSC). The effects of the benzodiazole acceptors on the thermal, optical, electrochemical, and photovoltaic properties of these low‐bandgap (LBG) polymers were investigated. These LBG polymers possessed large molecular weight (M_n) in the range of 3.85?5.13 × 10⁴ with high thermal decomposition temperatures, which demonstrated broad absorption in the region of 300?750 nm with optical bandgaps of 1.80?1.93 eV. Both the HOMO energy level (?5.38 to ?5.47 eV) and LUMO energy level (?3.47 to ?3.60 eV) of the LBG polymers were within the desirable range of ideal energy level. Under 100 mW/cm² of AM 1.5 white‐light illumination, bulk heterojunction PSC devices containing an active layer of electron donor polymers mixed with electron acceptor [6,6]‐phenyl‐C₆₁‐butyric acid methyl ester (PC₆₁BM) or [6,6]‐phenyl‐C₇₁‐butyric acid methyl ester (PC₇₁BM) in different weight ratios were investigated. The best performance of the PSC device was obtained by using polymer PP6DHTBT as an electron donor and PC₇₁BM as an acceptor in the weight ratio of 1:4, and a power conversion efficiency value of 1.20%, an open‐circuit voltage (V_oc) value of 0.75 V, a short‐circuit current (J_sc) value of 4.60 mA/cm², and a fill factor (FF) value of 35.0% were achieved. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

Reaktionsverhalten verschiedener Carbodiimide mit Ferrocen‐1, 1'‐dicarbonsäure

Reaction Behaviour of Several Carbodiimides with 1, 1'‐Ferrocenedicarboxylic Acid 1, 1'‐bis‐(1, 3‐dicyclohexylureidocarbonyl)‐ferrocene ( 1 ), 1, 1'‐bis‐(1, 3‐diisopropylureidocarbonyl)‐ferrocene ( 2 ) and ferrocene‐1, 1'‐bis‐N‐p‐tolylcarboxamide ( 6 ) were synthesized by melting down 1, 1'‐ferrocenedicarboxylic acid ( 7 ) together with N, N'‐dicyclohexylcarbodiimide (DCC), N, N'‐diisopropylcarbodiimide (DIC) or N, N'‐di‐p‐tolylcarbodiimide ( 8 ), respectively, without application of any solvent in a short space of time. Substance 1 , 2 , 1, 1'‐bis‐(1‐ethyl‐3‐tert‐butylureidocarbonyl)‐ferrocene ( 3 ), 1‐(1‐tert‐butyl‐3‐ethylureidocarbonyl)‐1'‐(1‐ethyl‐3‐tert‐butylureidocarbonyl)‐ferrocene ( 4 ) and 1, 1'‐bis‐(1‐tert‐butyl‐3‐ethylureidocarbonyl)‐ferrocene ( 5 ) were obtained in good yield by reacting 7 DCC, DIC, or N‐tert‐butyl‐N'‐ethylcarbodiimide ( 9 ), respectively, with in ethyl acetate for weeks. Transannular 1, 1'‐ferrocenedicarboxylic anhydride was not detectable or isolable in these reactions. All new compounds were characterized by ¹H‐NMR, ¹³C‐NMR, IR, MS and elementar analysis. In the case of 1 a single crystal structure analysis was made.     

Spectroscopic studies of charge transfer complexes of meso‐tetra‐p‐tolylporphyrin and its zinc complex with some aromatic nitro acceptors in different organic solvents

The charge transfer complex (CTC) formation of 5,10,15,20‐tetra(p‐tolyl)porphyrin (TTP) and zinc 5,10,15,20‐tetra(p‐tolyl)porphyrin with some aromatic nitro acceptors such as 2,4,6‐trinitrophenol (picric acid), 3,5‐dinitrosalicylic acid, 3,5‐dinitrobenzoic acid (DNB) and 2,4‐dinitrophenol (DNP) was studied spectrophotometrically in different organic solvents at different temperatures. The spectrophotometric titration, Job's and straight line methods indicated the formation of 1:1 CTCs. The values of the equilibrium constant (K_CT) and molar extinction coefficient (ε_CT) were calculated for each complex. The ionization potential of the donors and the dissociation energy of the charge transfer excited state for the CTC in different solvents was also determined and was found to be constant. The spectroscopic and thermodynamic properties were observed to be sensitive to the electron affinity of the acceptors and the nature of the solvent. No CT band was observed between Zn‐TTP as donor and DNP or DNB as acceptors in various organic solvents at different temperature. Bimolecular reactions between singlet excited TTP (¹TTP*) and the acceptors were investigated in solvents with various polarities. A new emission band was observed. The fluorescence intensity of the donor band decreased with increasing the concentration of the acceptor accompanied by an increase in the intensity of the new emission. The new emission of the CTCs can be interpreted as a CT excited complex (exciplex). Copyright © 2007 John Wiley & Sons, Ltd.     

Some donor-acceptor complexes of silicon phthalocyanine dianions

Studying the reaction of PcSiX₂ (X = Cl, OH) with KOH in DMSO we first discovered red D-A complexes [(Pc²⁻)·PcSiX²] and [(Pc²⁻)·O²] in which silicon phthalocyanine dianion Pc²⁻ is a donor, and the parent phthalocyanine silicon or oxygen are acceptors of electron density. The complexes were characterized by electron absorption, NMR, and ESR spectra. In the reactions with Me₃SiCl, H₂O, or CH₃COOH the complexes regenerate phthalocyanine and O₂. In O₂ atmosphere the [(Pc²⁻)·O₂] complex gradually degrades affording a product of unknown nature.     

Effect of lithium perchlorate on the spontaneous copolymerization of 4‐vinylpyridine with various electron‐rich vinyl monomers

The spontaneous copolymerization of 4‐vinylpyridine (4‐VP) activated with lithium perchlorate (LiClO₄) with various electron rich monomers (p‐methoxystyrene, MeOSt; p‐methylstyrene, MeSt; styrene, St) was investigated in various solvent systems at 75°C. Increasing the LiClO₄ concentration and the nucleophilicity of the electron rich monomer increased the copolymer yields. Both ¹H‐NMR and elemental analysis confirmed the almost 1:1 copolymer structure for VP/MeOSt system which possessed high molecular weight and narrow polydispersity (PDI). Compared to 4‐VP activated with zinc chloride, LiClO₄ systems showed slightly lower yields and much narrower PDI. We also investigated the spontaneous copolymerization of 4‐VP activated with various protic acids in the reaction with various electron rich comonomers. However, generally protic salt forms showed less solubility in organic solvents and showed low molecular weight polymer products with low yields. The proposed initiation mechanism exhibits the formation of a σ‐bond between the β‐carbons of the two donor‐acceptor monomers, creating the 1,4‐tetramethylene biradical intermediate initiating the copolymerization. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 1709–1716, 1999