| 1. |
- Scholz, S. M., et al.
(författare)
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Nanoporous Aggregates of ZnS Nanocrystallites
- 1998
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Ingår i: Applied organometallic chemistry. - : John Wiley & Sons. - 0268-2605 .- 1099-0739. ; 12:5, s. 327-335
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Tidskriftsartikel (refereegranskat)abstract
- During the synthesis of ZnS powders by wet chemical precipitation, the formation of nanoporous spheres is observed. The powders have been investigated using thermogravimetric analysis, X-ray diffraction and optical spectroscopies. Nanopore formation can be explained by several stages of growth. The formation of nanoparticles as primary particles is followed by their agglomeration forming secondary particles. These secondary particles are monodispersed spheres with a considerable porosity, because the agglomeration of the nanoparticles is unlikely to be volume-filling. The voids or nanopores formed by this agglomeration process in the secondary particles is estimated to comprise around 35% of the sphere volume. They are mainly filled with water and the residues of the chemical reagents. Water in the pores partially reacts with ZnS and forms hydrated sulphates. The chemical reagents used for the precipitation reactions are also found to be bound to the nanocrystallite's surfaces as ligands in some cases. Depending on the reaction conditions and reagents, the agglomeration of the nanoparticles can also be modified or hindered by the use of complexing agents acting as a sterically stabilizing surface layer on the nanocrystallites. The agglomeration of nanoparticles to larger units being a general phenomenon, this use of complexing agents to control pore formation and agglomerate size should be applicable to other nanocrystalline systems.
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| 2. |
- Abdelhamid, Hani Nasser, 1986-
(författare)
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MOFTextile : Metal-organic frameworks nanosheets incorporated cotton textile for selective vapochromic sensing and capture of pyridine
- 2023
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Ingår i: Applied organometallic chemistry. - : Wiley. - 0268-2605 .- 1099-0739. ; 37:5
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Tidskriftsartikel (refereegranskat)abstract
- Metal–organic frameworks (MOFs) improved several trends and are promising for industrial applications. However, current synthesis processes offer powder form, rendering their applications difficult. A simple solvothermal method offered an in situ growth of copper-based MOFs, for example, CuBDC (BDC: benzene-1,4-dicarboxylic acid) into a cotton textile; the material was denoted as CuBDC@Textile. CuBDCTextile was used as a solid sensor and adsorbent for volatile organic compounds (VOCs). It exhibited good vapochromic properties that enabled a colorimetric detection of pyridine (Py) via naked eyes with high selectivity and good sensitivity. Adsorption of pyridine via pervaporation using CuBDC@Textile was recorded. CuBDCTextile is a flexible textile with a high adsorption capacity (137.9 mg g−1) toward pyridine. It offered dual functional: sensor probe and adsorbent. The synthesis of CuBDC@Textile and their excellent performance as a sensor and adsorbent are promising for further investigation of the “MOFs on textile materials” topic.
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| 3. |
- Bhunora, Suraj, et al.
(författare)
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The use of Cu and Zn salicylaldimine complexes as catalyst precursors in ring opening polymerization of lactides: ligand effects on polymer characteristics
- 2011
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Ingår i: Applied Organometallic Chemistry. - : Wiley. - 1099-0739 .- 0268-2605. ; 25:2, s. 133-145
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Tidskriftsartikel (refereegranskat)abstract
- A range of monomeric tetra-coordinate copper (II) and zinc (II) complexes based on N,O-bidentate salicylaldimine Schiff base ligands has been synthesized and characterized using various spectroscopic techniques. These complexes were then evaluated as initiators in ring-opening polymerization of lactides at both 70 degrees C and 110 degrees C. The effect of structural changes in the complexes on the ability of these compounds to initiate lactide polymerization as well as the impact on the chemical and physical characteristics of the polymers obtained indicate that the coordination geometry of the metal complex, M-O bond length and substituents on the Schiff base ligand all play a role in the catalyst activity. Electronic factors were dominant in the case of the copper complexes while steric factors prevailed in the case of Zn initiators. Both the Zn and Cu complexes exhibit characteristics of living ring opening polymerization. Copyright (C) 2010 John Wiley & Sons, Ltd.
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| 4. |
- Buitrago, Elina, et al.
(författare)
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Selective hydrosilylation of ketones catalyzed by in situ-generated iron NHC complexes
- 2011
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Ingår i: Applied organometallic chemistry. - : Wiley. - 0268-2605 .- 1099-0739. ; 25:10, s. 748-752
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Tidskriftsartikel (refereegranskat)abstract
- Aryl alkyl-, heteroaryl alkyl- and dialkyl ketones were readily reduced to their corresponding secondary alcohols in high yields, using the commercially available and inexpensive polymeric silane polymethylhydrosiloxane (PMHS), as reducing agent. The reaction is catalyzed by an in situ-generated iron complex, conveniently generated from iron(II) acetate and the commercially available N-heterocyclic carbene (NHC) precursor IPr·HCl.
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| 5. |
- Chen, Baowei, et al.
(författare)
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Methylation of inorganic mercury by methylcobalamin in aquatic systems
- 2007
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Ingår i: Applied organometallic chemistry. - : John Wiley & Sons. - 0268-2605 .- 1099-0739. ; 21:6, s. 462-467
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Tidskriftsartikel (refereegranskat)abstract
- The methylation of inorganic Hg(II) by methylcobalamin in aquatic systems was studied using high-performance liquid chromatography coupled with UV-digestion cold vapor atomic fluorescence spectrometry (HPLC-UV-CV AFS). Monomethylmercury (MMC) could be positively identified as the reaction product in the aqueous solution. The salinity and pH of the aquatic system have great effects on the formation of MMC, because they could change the species of the reactants in the solution. From an electrophile reaction point of view, salinity and pH alter the electron density of the methyl donor and the electrophilicity of metal ion in the reaction system. This methylation of inorganic Hg(II) is shown to be possible even in highly saline solutions, which indicates its importance in aquatic environments. Kinetic experiments showed that the methylation reaction was fast and first-order for Hg(II). The first-order reaction rate was determined to be 0.00612 and 0.000287 min-1 for pH 5.0 and 1.5, respectively. It is suggested that this methylation could occur in the absence of enzymes, in which Hg(II) acts as an electrophile to attack methylcobalamin with a subsequent transfer of carbanion methyl group to the higher oxidized state of Hg(II).
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| 6. |
- Chen, Baowei, et al.
(författare)
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Simulate methylation reaction of arsenic(III) with methyl iodide in an aquatic system
- 2006
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Ingår i: Applied organometallic chemistry. - : John Wiley & Sons. - 0268-2605 .- 1099-0739. ; 20:11, s. 747-753
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Tidskriftsartikel (refereegranskat)abstract
- The methylation reaction of inorganic arsenic occurring in aquatic systems was studied by HPLC-HGAFS as a method to separate and detect soluble methylarsenic species. Transformation from inorganic arsenic to methylarsenic was essential for major changes in toxicity to organisms. Monomethylarsenic [AsOCH(3)(OH)(2)] was the only product in the methylation reaction of inorganic arsenic(III) with methyl iodide (MeI). This process can be described as an oxidative carbonium-ion transfer, with MeI acting as a methyl donor. From a thermodynamic point of view, the activity of the carbonium ion and pH were the two major influencing factors. The pH dependence of redox potential of As(III) was the reason for the effect of pH on methylation of arsenic. The influences of salinity and concentration of the methyl donor may be explained by their effects on the activity of carbonium. Moreover, kinetics experiments demonstrated that the methylation reaction was first-order for both As(III) and methyl iodide. First-order reaction rates were also calculated at different pH, salinity and MeI, and were found to be in the range 0.0026-0.0123 h(-1). The methylation rate varied largely under different reaction conditions.
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| 7. |
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| 8. |
- Gao, Aiping, et al.
(författare)
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Asymmetric oxidation of sulfides catalyzed by chiral (salen)Mn(III) complexes with a pyrrolidine backbone
- 2006
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Ingår i: Applied organometallic chemistry. - : Wiley. - 0268-2605 .- 1099-0739. ; 20:12, s. 830-834
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Tidskriftsartikel (refereegranskat)abstract
- Catalytic properties of a series of chiral (pyrrolidine salen)Mn(III) complexes for asymmetric oxidation of aryl methyl sulfides were evaluated. Moderate activity, good chemical selectivity and low enantioselectivity were attained with iodosylbenzene as a terminal oxidant. Enantioselectivity of sulfide oxidation was affected slightly by polar solvent and the sulfoxidation carried out in THF for thioanisole and in CH3CO2Et for electron-deficient sulfides gave better enatioselctivities. The addition of the donor ligand PPNO (4-phenylpyridine N-oxide) or MNO (trimethylamine N-oxide) only has a minor positive effect on the enantioselectivity. Also explored was the steric effect of the N-aza-substituent in the backbone of (pyrrolidine salen)Mn(III) complexes on the enantioselectivity of sulfide oxidation. The sulfides' access pathway is discussed based on the catalytic results.
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| 9. |
- Kumar, Saurabh, et al.
(författare)
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Topical progress in medicinal applications of self‐assembled organoplatinum complexes using diverse Pt(II)‐ and N‐based tectons
- 2022
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Ingår i: Applied organometallic chemistry. - : John Wiley & Sons. - 0268-2605 .- 1099-0739. ; 36:11
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Forskningsöversikt (refereegranskat)abstract
- The last decade witnessed a flourishing advancement in the design and synthesis of discrete Pt-based metallamacrocycles self-assembled using coordination bonds. Such supramolecular entities were obtained using novel nitrogen-based ligands and have wide and versatile applications such as chemical sensors, catalysts, theranostic agents, optical materials, drug delivery, and others. Herein, we present a concise review of recently reported metallacycles obtained using various N-functionalized donor and Pt acceptor tectons of various shapes and sizes. While highlighting recent developments in the syntheses and characterization of such platinacycles, we lay special emphasis on their biological interactions and applications.
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| 10. |
- Liu, Haibin, et al.
(författare)
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Influence of substituents in the salicylaldehyde-derived Schiff bases on vanadium-catalyzed asymmetric oxidation of sulfides
- 2008
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Ingår i: Applied organometallic chemistry. - : Wiley. - 0268-2605 .- 1099-0739. ; 22:5, s. 253-257
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Tidskriftsartikel (refereegranskat)abstract
- A series of chiral Schiff bases (L-1-L-5) with different substituents in the salicylidenyl unit were prepared from condensation of 3-aryl-5-tert-butylsalicylaldehyde derivatives and optically active amino alcohols. Bromination of 3-phenyl-5-tert-butylsalicylaldehyde gave an unexpected product 3-(4-bromophenyl)-5-bromosalicylaldehyde, from which the corresponding Schiff base ligands L-6 and L-7, derived from (S)-valinol and (S)-tert-leucinol, respectively, were prepared. Ligands L-1-L-7 were applied to the vanadium-catalyzed asymmetric oxidation of aryl methyl sulfides. Under the optimal conditions, the oxidation of the thioanisole with H2O2 as oxidant in CH2Cl2 catalyzed by VO(acac)(2)-L-1-L-7 gives good yields (74-83%) with moderate enantioselectivity (58-77% ee). Ligand L-7, containing a 4-bromophenyl group on the 3-position and a Br atom on the 5-position of the salicylidenyl moiety, displays an 80-90% ee for vanadium-catalyzed oxidation of methyl 4-bromophenyl sulfide and methyl 2-naphthyl sulfide.
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