| 1. |
- Adams, Samuel J., et al.
(författare)
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Surfactant-Enhanced Luminescence Lifetime for Biomolecular Detection on Luminescent Gold Surfaces Decorated with Transition Metal Complexes
- 2018
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Ingår i: ChemistrySelect. - 2365-6549. ; 3, s. 3251-3257
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Tidskriftsartikel (refereegranskat)abstract
- In the development of sensors based on multimodal detection, luminescent probes are attractive for providing a sensitive signal read-out, based either on intensity, wavelength shift or luminescence lifetime. The implicit simplicity of the devices that can be created is dependent of the judicious design of the multimodal probe. We have used transition metal probes which offer combined versatility due to their electroactive and photoluminescent properties, as well as their sensitivity to local environment. We report the influence of surfactant upon the formation of luminescent surfaces with metal complexes based on ruthenium(II), iridium(III) and osmium(II) bearing surface active groups. The results reveal an enhancement of the luminescence lifetime when a mixed monolayer with surfactant is formed. Characteristically, the luminescence lifetime of the ruthenium tris-bipyridyl complex attached to the gold surface increases from 210 ns to 765 ns in the presence of a fluorinated surfactant. The luminescence signal of the modified gold surfaces is also responsive to bovine serum albumin and fetal bovine serum adsorption, demonstrating interaction of the protein with the metal complex in the presence of the surfactant. The biomolecular interaction with the functionalised surfaces is also evidenced by surface plasmon resonance response.
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| 2. |
- Annes, Sesuraj Babiola, et al.
(författare)
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Deep Eutectic Solvent Mediated Alkyne-Carbonyl Metathesis (ACM) Reaction for the Synthesis of 2H-Chromene Derivatives
- 2019
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Ingår i: ChemistrySelect. - : Wiley. - 2365-6549. ; 4:20, s. 6245-6249
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Tidskriftsartikel (refereegranskat)abstract
- 2H-Chromene is an important structural motif present in many biologically active compounds, natural products and showed many other properties. Deep Eutectic Solvent (DES) an environmentally benign and alternative to the conventional organic volatile solvents has been utilized first time for the synthesis of the 2H-chromene derivatives in moderated to excellent yields. The DES is recycled for 5 times for the synthesis of 2H-chromene derivatives. Based on the stability of ring size, we justified the regio-selectivity on the formation of cyclization product. Based on the control experiments, we ruled out the free radical mechanism and propose the ACM mechanistic path to construct chromene skeleton.
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| 3. |
- Ans, Muhammad, et al.
(författare)
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Designing Three‐dimensional (3D) Non‐Fullerene Small Molecule Acceptors with Efficient Photovoltaic Parameters
- 2018
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Ingår i: ChemistrySelect. - : WILEY-VCH VERLAG GMBH. - 2365-6549. ; 3:45, s. 12797-12804
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Tidskriftsartikel (refereegranskat)abstract
- Three dimensional (3D) acceptor‐donor‐acceptor (A−D‐A) type small molecules (M1, M2, M3 and M4) are theoretically investigated for optoelectronic properties. The designed molecules contain spirobifluorene as core unit linked with end capped acceptors through four four thieno‐[3,2‐b]Thiophene (TT) units. The end capped acceptors are (3‐methyl‐2‐thioxothiazolidin‐4‐one) (M1), 2‐(2‐ethylidene‐5,6‐difluoro‐3‐oxo‐2,3‐dihydroinden‐1‐ylidene)malononitrile (M2), 2‐(3‐ethyl‐4‐oxothiazolidin‐2‐ylidine)malononitrile (M3) and 2‐(2‐ethylidene‐5,6‐dicyano‐3‐oxo‐2,3‐dihydroinden‐1‐ylidene)malononitrile (M4). The photovoltaic parameters of the designed molecules are compared with the recently reported reference compound R. Among all designed molecules, M4 is a low energy gap material (2.28 eV), broad absorption which is attributed to excellent communication between strong electron withdrawing end capped acceptors through extended conjugation. All newly designed molecules have lower binding energy as compared to reference molecule R which results in higher exciton dissociation in excited state. The reorganization energy calculations indicate good charge transfer ability of the designed molecules. M4 shows the lowest λe (0.0022) value with respect to the reference molecule R (0.034) which signifies its enhanced electronic transport behavior. The calculated open circuit voltages (Voc) ranges from 1.97 to 2.36 eV, 2.11 to 2.49 eV and 1.9 eV to 2.28 eV with respect to three different well known donor materials PTB7‐Th, PBDB−T and P3HT, respectively.
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| 4. |
- Asfaw, Habtom D., et al.
(författare)
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Boosting the thermal stability of emulsion–templated polymers via sulfonation : an efficient synthetic route to hierarchically porous carbon foams
- 2016
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Ingår i: ChemistrySelect. - : Wiley. - 2365-6549. ; 1:4, s. 784-792
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Tidskriftsartikel (refereegranskat)abstract
- Hierarchically porous carbon foams with specific surface areas exceeding 600 m2 g−1 can be derived from polystyrene foams that are synthesized via water-in-oil emulsion templating. However, most styrene-based polymers lack strong crosslinks and are degraded to volatile products when heated above 400 oC. A common strategy employed to avert depolymerization is to introduce potential crosslinking sites such as sulfonic acids by sulfonating the polymers. This article unravels the thermal and chemical processes leading up to the conversion of sulfonated high internal phase emulsion polystyrenes (polyHIPEs) to sulfur containing carbon foams. During pyrolysis, the sulfonic acid groups (-SO3H) are transformed to sulfone (-C-SO2-C-) and then to thioether (-C−S-C-) crosslinks. These chemical transformations have been monitored using spectroscopic techniques: in situ IR, Raman, X-ray photoelectron and X-ray absorption near edge structure spectroscopy. Based on thermal analyses, the formation of thioether links is associated with increased thermal stability and thus a substantial decrease in volatilization of the polymers.
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| 5. |
- Aslan, Sema, et al.
(författare)
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Development of a Bioanode for Microbial Fuel Cells Based on the Combination of a MWCNT-Au-Pt Hybrid Nanomaterial, an Osmium Redox Polymer and Gluconobacter oxydans DSM 2343 Cells
- 2017
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Ingår i: ChemistrySelect. - : Wiley. - 2365-6549. ; 2:36, s. 12034-12040
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Tidskriftsartikel (refereegranskat)abstract
- In this work, a carbon felt electrode (CFE) was modified with a multiwalled carbon nanotube-gold-platinum (MWCNT-Au-Pt) hybrid nanomaterial and integrated with an osmium redox polymer (OsRP, [Os(2, 2’-bipyridine)2(poly-vinylimidazole)10Cl]Cl) and Gluconobacter oxydans DSM 2343 (G. oxydans) cells. The developed electrode was used as the bioanode in a 5.0 mM K3Fe(CN)6mediator containing phosphate buffer (pH 6.5) anolyte and combined with a Pt wire cathode in phosphoric acid medium (pH 3.5). As a result, a two chamber microbial fuel cell (MFC) was formed, in which an activated Nafion membrane was used as a proton exchange membrane. The OsRP/G.oxydans/MWCNT-Au-Pt/CFE based bioanode was electrochemically examined in differently deoxygenated bioanode chambers and additionally the amounts of hybrid nanomaterial and OsRP were optimized. In terms of MFC characteristics, it was found that an anaerobic OsRP/G.oxydans/MWCNT-Au-Pt/CFE bioanode based MFC had a maximum power density of 32.1 mW m-2(at 90 mV), a maximum current density of 1032 mA m-2and a charge transfer efficiency (E%) value of 22.30 (open circuit potential 180 mV).
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| 6. |
- Bisagni, Serena, et al.
(författare)
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Enhancing the Activity of a Dietzia sp. D5 Baeyer-Villiger Monooxygenase towards Cyclohexanone by Saturation Mutagenesis
- 2017
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Ingår i: ChemistrySelect. - : Wiley. - 2365-6549. ; 2:24, s. 7169-7177
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Tidskriftsartikel (refereegranskat)abstract
- A recombinant Baeyer-Villiger monooxygenase, BVMO4 from Dietzia sp. D5 has been previously reported. The enzyme exhibited good thermostability and was active with a wide range of cyclic ketone substrates but catalysed poorly the conversion of cyclohexanone to caprolactone. The present work focuses on protein engineering of BVMO4 to improve the conversion of cyclohexanone. Thus, a structural model of BVMO4 was generated and used in combination with literature information on substrate specificity of BVMOs to identify ‘hotspots’ whose mutation would influence substrate specificity. Site saturation mutagenesis was performed on 12 selected sites and 528 mutants were screened with expected coverage of about 98 %. About one-fourth of the mutants screened exhibited more than 50 % increase in cyclohexanone oxidation activity. Compared to the wild type BVMO, the best mutants, Y499I, Y499F and Y499 L have shown about 12-fold increase for caprolactone production.
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| 7. |
- Blomkvist, Björn, et al.
(författare)
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Mild and Rapid Aniline/HBF4 center dot DEE-Catalysed Formation of Sulfinyl Imines
- 2019
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Ingår i: ChemistrySelect. - : Wiley-VCH Verlagsgesellschaft. - 2365-6549. ; 4:25, s. 7431-7436
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Tidskriftsartikel (refereegranskat)abstract
- The combination of anline and tetrafluoroboric acid diethyl etherate (2.5 mol% and 5 mol%, respectively) significantly accelerates the formation of sulfinyl imines in dichloromethane and isopropylacetate at room temperature compared to previous procedures. A DFT and NMR spectroscopic study shows that the anilinium tetrafluoroborate complex is solvated by sulfinamide molecules in the initial state and that the rate-limiting step of the reaction is the addition of the sulfinamide molecule to the protonated aniline-based imine. In addition, the catalytic system was also utilised in a one-pot, two step reaction, where the in situ formed sulfinyl imine was arylated in a rhodium catalysed reaction with high diastereoselectivity.
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| 8. |
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| 9. |
- El Maatougui, Abdelaziz, et al.
(författare)
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3-Oxopyridazin-5-yl-Chalcone Hybrids : Potent Antiplatelet Agents That Prevent Glycoprotein IIb/IIIa Activation
- 2017
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Ingår i: CHEMISTRYSELECT. - : Wiley. - 2365-6549. ; 2:17, s. 4920-4933
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Tidskriftsartikel (refereegranskat)abstract
- A novel family of potent and broad-spectrum antiplatelet agents has been discovered by exploration of a library of 3-oxopyridazin-5-yl-chalcone hybrids. The pharmacological evaluation of the collection established the most salient features of the SAR in this series and allowed the identification of lead compounds that exhibit antiplatelet activity that is substantially superior to drugs in clinical use and 3,4-methylenedioxy-β-nitrostyrene (MNS). The derivatives reported herein act on GPIIb/IIIa, but in a different manner to classical antagonists (e.g., tirofiban), by preventing GPIIb/IIIa activation. Given their mechanism of action, these compounds might avoid the adverse effects of antagonists (paradoxical GPIIb/IIIa activation) and constitute attractive pharmacological tools for the development of tailored agents for the treatment of platelet-dependent thrombosis.
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| 10. |
- Gao, Jiajia, et al.
(författare)
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Crystallography as Forensic Tool for Understanding Electrolyte Degradation in Dye-sensitized Solar Cells
- 2017
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Ingår i: CHEMISTRYSELECT. - : WILEY-V C H VERLAG GMBH. - 2365-6549. ; 2:4, s. 1675-1680
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Tidskriftsartikel (refereegranskat)abstract
- The precipitation of solid compounds from model electrolytes for liquid dye-sensitized solar cells has a story to tell regarding decomposition processes to be expected in such systems. Of course, the crystal lattice energy for a specific crystalline compounds plays a role in what compound that will eventually precipitate, but the compounds nevertheless serve as indicators for what type of processes that take place in the solar cell electrolytes upon ageing. From the compounds isolated in this study we learn that both ligand exchange processes, double-salt precipitation and oxidation are degradation processes that should not be overlooked when formulating efficient and stable electrolytes for this type of electrochemical system.
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