S-dioxide Derivatives Research Articles

Synthesis, structure and mechanofluorochromic properties of phenothiazine-S-oxide and phenothiazine-S,S-dioxide derivatives

In this work, two novel luminescent molecules containing distorted phenothiazine-S-oxide and phenothiazine-S,S dioxide skeletons were synthesized by oxidation reactions using different oxidants (m-chloroperoxybenzoic acid, acetic acid /hydrogen peroxide). The target compounds were all confirmed by 1H NMR, 13C NMR and EI-MS. Combined with the results of UV–vis absorption spectra and fluorescence emission spectra, we found that the different oxidation states of S-atom, from sulfide (+2) to sulfoxide (+4) and sulfone (+6), led to the blue, yellow-green and yellowish fluorescence of these compounds in the solid states. Subsequent studies showed that the molecule containing the phenothiazine-S-oxide skeleton exhibited obvious solvatochromism, and the increase of solvent polarity induced a red-shift in the emission wavelength. Moreover, this molecule also exhibited a rare self-recovery mechanochromatic behavior. In addition, these properties were further confirmed by theoretical calculations and X-ray single-crystal diffraction analysis.

1,2,5-ThiadiazolineS,S-dioxide derivatives as corrosion inhibitors for mild steel in sulphuric acid solution. Electrochemical studies and cytotoxic effect evaluation

The first report on 1,2,5-thiadiazolineS,S-dioxide derivatives as effective corrosion inhibitors is presented. The biological assay results evidence the necessity to perform cytotoxicity tests for the new compounds.

Dibenzothiophene-S,S-dioxide derivatives containing triphenylamine and tetraphenylethene: Synthesis, aggregation-induced emission and electroluminescence

Several well-defined donor-acceptor (D-A) dibenzothiophene-S,S-dioxide (SO) derivatives possessing aggregation-induced emission (AIE) behaviour decorated by tetraphenylethene (TPE) and triphenylamine (TPA) were synthesized and characterized. The photophysical, thermal, electrochemical and electroluminescent (EL) properties, as well as the AIE property of the luminogens were discussed. All the luminogens show high thermal stability and exhibit good photoluminescence, and exhibit atypical AIE characteristic. Among the three OLEDs, the device of TPA–FSO–TPA showed the best performances with a Von of 4.0 V, LEmax of 10.05 cd A−1, EQEmax of 3.8% and Lmax of 14,670 cd m−2. Upon change of the operating voltage, the electroluminescent (EL) spectra of the devices based on TPA–FSO–TPA, TPA–FSO–TPE and TPE–FSO–TPE show negligible shift, indicating good device stability could be achieved in this system.

Germanium-Bridged 2-Phenylbenzoheteroles as Luminophores Exhibiting Highly Efficient Solid-State Fluorescence.

[1]Benzogermolo[3,2-b]indoles, [1]benzogermolo[3,2-b]benzofuran, [1]benzogermolo[3,2-b]benzothiophene, and [1]benzogermolo[3,2-b]benzothiophene-S,S-dioxide were synthesized from the corresponding 3-bromo-2-(2-bromophenyl)benzoheteroles and characterized. A comparison of the absorption spectra of the Ph2 Ge- and Ph2 Si-bridged 2-phenylindoles reveals that the Ge bridge has the effect of slightly widening the HOMO-LUMO energy gap of the bridged 2-phenylindole π-system with regard to the Si-bridged system. Replacement of the indole ring by benzofuran or benzothiophene rings induces blueshifts in the absorption spectrum, whereas the absorption spectrum of the benzothiophene-S,S-dioxide derivative was redshifted with respect to the indole derivative. These results are consistent with the changes in the HOMO-LUMO energy gaps calculated by using density functional theory. The Ph2 Ge-bridged indole, benzofuran, and benzothiophene-S,S-dioxide derivatives exhibit brilliant fluorescence in the violet-to-blue region with good-to-excellent quantum yields in toluene (λem =376-439 nm, Φ=0.62-0.99) and powder form (λem =401-451 nm, Φ=0.64-0.80).

VIT-CMJ2: Endophyte of Agaricus bisporus in Production of Bioactive Compounds.

Agaricus bisporus is an edible basidiomycete fungus. Both the body and the mycelium contain compounds comprising a wide range of antimicrobial molecules, contributing in improvement of immunity and tumor-retardation. The presence of endophytes capable of producing bioactive compounds was investigated in Agaricus bisporus. Endophytes from Agaricus bisporus was isolated on LB agar. The obtained isolates were characterized morphologically and biochemically. Further 16S rRNA sequencing was implemented for molecular analysis of isolates. The isolate was mass produced and the bioactive compounds were extracted using ethyl acetate, chloroform and hexane. Agar well diffusion method was carried out to seek the potential of any antimicrobial activity of the crude bioactive compounds against known pathogens. GC-MS and FT-IR analysis were performed for the identification of bioactive compounds. VIT-CMJ2 was identified as Enterobacter sp. as revealed by 16S rRNA sequencing. Chloroform extract of VIT-CMJ2 showed a maximum zone of inhibition of 19 mm against Salmonella typhi followed by hexane and ethyl acetate extracts. The GC-MS analysis revealed the presence of several bioactive compounds having effective antimicrobial activity like butyl ester, Behenicalcohol, S , S-dioxide derivatives and some others which were later confirmed by FT-IR spectral stretches. The present study shows the insight on the way endophytes interact with Agaricus bisporus; thereby improving the nutritional profile.

Blue light-emitting polymers containing fluorene-based benzothiophene-S,S-dioxide derivatives

Blue light-emitting polymers were synthesized via introducing a 9,9-dioctylfluorene bis[2,3-b;6,7-b]benzo-[d]thiophene-S,S-dioxide (FBTO) unit into the polyfluorene or polycarbazole backbone.

Dibenzothiophene-S,S-dioxide based medium-band-gap polymers for efficient bulk heterojunction solar cells

Medium-band-gap polymers based on indacenodithiophene (IDT) and dibenzothiophene-S,S-dioxide (SO) derivatives, PIDT-SO and PIDT-DHTSO, were synthesized via a microwave assisted Stille polycondensation. The polymers have the maximum absorption ∼500nm, high absorption coefficients above 0.6×10−2nm−1, and medium band gaps of ∼2.2eV. Their hole mobilities are around 2×10−4cm2V−1s−1 as measured by field effect transistors. The photovoltaic performances of the polymers were investigated on the inverted bulk heterojunction (BHJ) devices of ITO/PFN/PIDT-DHTSO:PC71BM (1:3, w/w)/MoO3/Al, and a power conversion efficiency (PCE) of 3.81% with an open-circuit voltage (Voc) of 0.95 V, a short-circuit current (Jsc) of 8.20mAcm−2 and a fill factor (FF) of 48% were achieved. Those results indicated that dibenzothiophene-S,S-dioxide derivatives could be an excellent electron-deficient building block for medium-band-gap electron-donor polymers.

Fluorescent oligomers of dibenzothiophene-S,S-dioxide derivatives: the interplay of crystal conformations and photo-physical properties

Fluorescent oligomers where the backbone of dibenzothiophene-S,S-dioxide acts as the acceptor and side chains of aryl methoxy, fluorene, and arylamine act as the donors have been effectively synthesized by the palladium-catalyzed Suzuki coupling reactions, and the photo-physical properties of the compounds were investigated. From the single-crystal XRD patterns the compounds reveal a twisted conformation with an intramolecular structure and show close relationship between intramolecular or intermolecular charge transfer and their photo-physical properties. These patterns provide more comprehensive information, which is unattainable from 1H NMR and 2D-COSY spectra. The emission spectrum in the range of 450–510nm can be finely tuned by systematically altering the position of substitution on the donor units of side chains connected with the backbone acceptor. The fabricated devices displayed a sky blue to deep green in terms of color and performed the CIE (x,y) coordinates with values of (0.18–0.21, 0.25–0.46), respectively.

Live-Cell-Permeant Thiophene Fluorophores and Cell-Mediated Formation of Fluorescent Fibrils

In our search for thiophene fluorophores that can overcome the limits of currently available organic dyes in live-cell staining, we synthesized biocompatible dithienothiophene-S,S-dioxide derivatives (DTTOs) that were spontaneously taken up by live mouse embryonic fibroblasts and HeLa cells. Upon treatment with DTTOs, the cells secreted nanostructured fluorescent fibrils, while cell viability remained unaltered. Comparison with the behavior of other cell-permeant, newly synthesized thiophene fluorophores showed that the formation of fluorescent fibrils was peculiar to DTTO dyes. Laser scanning confocal microscopy of the fluorescent fibrils showed that most of them were characterized by helical supramolecular organization. Electrophoretic analysis and theoretical calculations suggested that the DTTOs were selectively recognized by the HyPro component of procollagen polypeptide chains and incorporated through the formation of multiple H-bondings.

A new route to thiopyran S, S-dioxide derivatives via an overall ring-enlargement protocol from 3-nitrothiophene

(1 E,3 Z)-1-Aryl-4-methanesulfonyl-2-nitro-1,3-butadienes ( 8), derived from the initial ring-opening of 3-nitrothiophene ( 5), have been found to undergo a facile base-induced cyclization leading to thiopyran S, S-dioxides ( 9), thus furnishing a further example of effective ring-enlargement from 5- to 6-membered sulfur heterocycles. Compounds 9 are obtained as single racemic mixtures in satisfactory yields; they still contain a nitrovinylic moiety, which can be exploited for further modifications targeted to new derivatives endowed with either synthetic or pharmacological potentialities e.g., in the field of L-type Ca 2+-channel blockers.

Synthesis, antimalarial activity, structure–activity relationship analysis of thieno-[3,2- b]benzothiazine S, S-dioxide analogs

An improved procedure for the synthesis of 3-amino-9-arylsubstituted-thieno[3,2- b]benzothiazine S, S-dioxide 2-decarboxylated is reported. Thieno-[3,2- b]benzothiazine S, S-dioxide derivatives were investigated for their abilities to inhibit β-hematin formation, hemoglobin hydrolysis and in vivo for their efficacy in rodent Plasmodium berghei. Compounds 5j– o were the most promising as inhibitors of hemoglobin hydrolysis, however, the compounds are not as efficient as chloroquine. A structure–activity relationship (SAR) study was carried out in this series. Our results allow us to determine the minimal structural requirements to produce the biological response.

A new method for the synthesis of tetrahydrothiophene-S,S-dioxide derivatives: the Michael ring closure reaction between halomethyl (E)-β-styryl sulfones and CH-acids

Bromomethyl and chloromethyl (E)-β-styryl sulfones enter a Michael ring closure reaction with sodium enolates prepared from dimethyl malonate, malononitrile and ethyl acetoacetate. The condensation results in formation of substituted tetrahydrothiophene-S,S-dioxides. It is a new instance of α-haloalkyl sulfones transformations, which are not connected with Ramberg–Bäcklund reaction.

Nonradiative Relaxation in Thiophene-S,S-dioxide Derivatives: The Role of the Environment

The intramolecular radiative and nonradiative relaxation processes of three thiophene-S,S-dioxide derivatives with different molecular rigidity are investigated in different solutions and in inert matrix. We show that the fluorescence quantum efficiency and the relaxation dynamics are strongly dependent on the environment viscosity, whereas they are almost independent of the environment polarity. We demonstrate that this strong dependence is due to an environment dependent nonradiative decay rate, whereas no relevant variations of the radiative decay rate are observed. We demonstrate that the dipole coupling with the solvent does not provide an efficient nonradiative decay channel and that the S(n) - S(1) vibrational relaxation is very efficient in all of the molecules and for all of the investigated environments. Moreover first-principles time-dependent density-functional theory calculations in the correct, i.e., excited-state, molecular conformation, suggest that significant contributions of intersystem crossing to the triplet manifold can be excluded. We then conclude that the main nonradiative process determining the fluorescence quantum efficiency of this class of molecules is S(1) - S(0) internal conversion (IC). An explanation for the IC rate dependence in terms of the environment viscosity, molecular rigidity, S(1) - S(0) energy-gap, and molecular volume is presented.

Electron-transporting materials for organic electroluminescent and electrophosphorescent devices

One of the requirements for efficient organic electroluminescent devices (OLEDs) is balanced charge injection from the two electrodes and efficient transport of both holes and electrons within the luminescent layer in the device structure. Many of the common luminescent conjugated polymers, e.g. derivatives of poly(phenylenevinylene) and poly(fluorene), are predominantly hole transporters (i.e. p-dopable). This article gives a brief overview of organic electroluminescence and electrophosphorescence and provides a more detailed consideration of ways in which electron transport in these systems has been enhanced by the incorporation of electron-deficient (i.e. n-dopable) small molecules and polymers into the devices, either as blends or by covalent attachment of sub-units to the luminophore or as an additional electron-transporting, hole-blocking (ETHB) layer adjacent to the cathode. The chemical structures of these systems are presented and their roles are assessed. Most of these ETHB molecules are electron-deficient aromatic nitrogen-containing heterocycles, e.g. derivatives of 1,3,4-oxadiazole, pyridine, pyrimidine, pyrazine, quinoline, etc. Non-aromatic thiophene-S,S-dioxide derivatives are also discussed. The article is written from an organic chemist's perspective.

Effects of intermolecular interactions on photoluminescence efficiency of crystalline thienylene-S,S-dioxide molecular semiconductors

The effects of intermolecular interactions on the photoluminescence (PL) quantum efficiency of differently substituted thienylene-S,S-dioxide derivatives in the crystalline phase are investigated. The exciton resonance interactions and the transfer integrals are evaluated using a quantum chemistry approach by considering the supramolecular structures obtained from X-ray data. Two classes of thienylene-S,S-dioxides are investigated: (1) rigid, fused ring compounds, for which the PL quantum efficiency can be well correlated with the rate of formation of non-radiatively decaying charge-transfer pairs upon photoexcitation; (2) flexible oligothiophenes for which the high PL quantum efficiency in the solid-state is assigned to a decrease of intramolecular internal conversion process, as confirmed by time-resolved PL measurements in solvents of different viscosity.

Effects of intermolecular interactions on photoluminescence efficiency of crystalline thienylene-S,S-dioxide molecular semiconductors

The effects of intermolecular interactions on the photoluminescence (PL) quantum efficiency of differently substituted thienylene-S,S-dioxide derivatives in the crystalline phase are investigated. The exciton resonance interactions and the transfer integrals are evaluated using a quantum chemistry approach by considering the supramolecular structures obtained from X-ray data. Two classes of thienylene-S,S-dioxides are investigated: (1) rigid, fused ring compounds, for which the PL quantum efficiency can be well correlated with the rate of formation of non-radiatively decaying charge-transfer pairs upon photoexcitation; (2) flexible oligothiophenes for which the high PL quantum efficiency in the solid-state is assigned to a decrease of intramolecular internal conversion process, as confirmed by time-resolved PL measurements in solvents of different viscosity.

Use of 19F NMR spectroscopy to probe enzymatic oxidation of fluorine‐tagged sulfides

AbstractA novel 19F NMR‐based method for monitoring the enzymatic oxidation of thia fatty acid analogues is presented. Our approach is based on the observation that methyl ω‐monofluorinated 9‐thia‐ and 10‐thiaoctadecanoates and their S‐oxide and S‐dioxide derivatives are easily distinguishable via their 1H‐decoupled 19F spectra. These long‐range substituent effects were used to probe the regio‐ and chemoselectivity of stearoyl ACP (acyl carrier protein) Δ9 desaturase‐mediated sulfoxidation. The results clearly demonstrate that mono‐oxygenation of a 10‐thia analogue ACP Δ9 desaturase was more efficient than that of a 9‐thia substrate. A product previously undetected by TLC was observed for the first time in the product mixture obtained from 18‐fluoro‐9‐thiaoctadecanoyl‐ACP. Copyright © 2002 John Wiley & Sons, Ltd.

C2-Symmetric sulfur derivatives of 2,2′,3,3′-tetramethoxybiphenyl

A practical route to prepare dithioether, thiophene and thiophene S-dioxide derivatives of 2,2′,3,3′-tetramethoxy-1,1′-biphenyl 1 is described. Resolution of 6,6′-bis(methylthio)-3,3′-dimethoxy-[1,1′-biphenyl]-2,2′-diol 15 was achieved and its absolute configuration was assigned by X-ray analysis of the corresponding phosphorothioamidate diastereomer 18.

Stereoespecific syntheses of 2,3-dimethyl-1,4-oxathian S-oxides

The stereoespecific syntheses of cis - and trans -2,3-dimethyl-1,4-oxathian, their diastereomeric S-oxides and their S-dioxide derivatives are reported. The key step in the synthetic pathways is the cyclization ofa 2-hydroxyalkyl vinylsulphoxide, by intramolecular conjugated addition with retention of configuration in the C and S chiral centers.

Hydrotreating of halogeno-benzo[ b]thiophenes and their S-oxide and S-dioxide derivatives over [formula omitted] catalyst

Hydrotreating experiments were carried out with a sulfided CoO-MoO 3 Al 2O 3 catalyst at various pressures and temperatures under stirred batch reactor conditions. The reactants were hydrogen and pure halogeno-sulfur compounds in the benzothiophene series. In the case of the benzo[ b]-thiophene itself, the dehalogenation reaction takes place without any observed hydrogenation or hydrodesulfurization. For the S-oxidized derivatives a deoxygenation takes place first. For the halogeno-sulfone the dehalogenation is also the first step of the overall process. In the halogenobenzo[ b]thiophene series a correlation between the rate constants and the ionisation potential of the molecules suggests that electronic effects may be preponderant.