One-step synthesis of highly water-dispersible Mn(3)O(4) nanocrystals

Highly water-dispersible Mn(3)O(4) nanocrystals with well-controlled size, size distribution and high crystallinity have been successfully synthesized through a modified polyol process. Poly(acrylic acid) is used as the capping agent, conferring upon the particles high water-dispersion, of which the carboxylate groups partially bind to the nanocrystal surface and the uncoordinated carboxylate groups extend into water. The water-dispersible Mn(3)O(4) nanocrystals can be further transferred to nonpolar solvent by linking oleylamine molecules through electrostatic interaction. The as-prepared Mn(3)O(4) nanocrystals exhibit ferromagnetic behavior at low temperature and weak paramagnetic behavior at room temperature. The Curie-Weiss temperature and the blocking temperature are 40 K and 32 K, respectively.     

One-step synthesis of fluorescein modified nano-carbon for Pd(II) detection via fluorescence quenching

Carbon black (CB) nanoparticles modified with fluorescein, a highly fluorescent molecule, were prepared using a facile and efficient methodology. Simply stirring CB in aqueous solution containing fluorescein resulted in the strong physisorption of fluorescein onto the CB surface. The resulting Fluorescein/CB was then characterised by means of X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV), fluorescence microscopy and fluorescence spectroscopy. The optimum experimental conditions for fluorescence of Fluorescein/CB viz. fluorescence excitation and emission wavelengths, O(2) removal and the amount of Fluorescein/CB used, were investigated. The Fluorescein/CB was used as a fluorescent probe for the sensitive detection of Pd(II) in water, based on fluorescence quenching. The results demonstrated that the fluorescence intensity of Fluorescein/CB decreased with increasing Pd(II) concentration, and the fluorescence quenching process could be described by the Stern-Volmer equation. The limit of detection (LOD) for the fluorescence quenching of Fluorescein/CB by Pd(II) in aqueous solution was found to be 1.07 μM (based on 3σ). Last, approaches were studied for the removal of Fe(III) which interferes with the fluorescence quenching of Fluorescein/CB. Complexation of Fe(III) with salicylic acid was used to enhance and control the selectivity of Fluorescein/CB sensor towards Pd(II) in the presence of Fe(III).     

3-(Aryl)-2-sulfanylpropenoates of mercury(II) and phenylmercury(II)

Compounds [HQ]₂[Hg(L)₂] and [HQ][PhHg(L)] [where HQ = diisopropylammonium cation; L = pspa, fspa, tspa, where p = 3-(phenyl), f = 3-(2-furyl), t = 3-(2-thienyl), and spa = 2-sulfanylpropenoato] have been prepared by the reaction of mercury(II) acetate or phenylmercury(II) acetate with the corresponding acid in the presence of diisopropylamine in ethanol. The compounds have been characterized by elemental analysis, FAB mass spectrometry and IR and NMR (¹H, ¹³C) spectroscopy. The crystal structures of the [HQ]₂[Hg(L)₂] compounds show the presence of diisopropylammonium cations and [Hg(L)₂]²⁻ anions. In each anion the Hg atom is in an HgO₂S₂ environment and this can be described as nido-tbp. The crystal structures of the [HQ][PhHg(L)] compounds show the presence of diisopropylammonium cations and [PhHg(L)]⁻ anions in which the Hg atom adopts an HgCOS distorted T-environment. The NMR data suggest that the coordination mode of the ligand L²⁻ determined by X-ray diffractometry in the solid remains in solution.     

Preparation and Spectral Investigation of Bis[N(2-methyl-phenyl) 4-Nitro-thiobenzamidato] mercury(II), Bis[N(2-methoxy-phenyl) 4-Nitro-thiobenzamidato]mercury(II), and Bis[N(2-chloro-phenyl) 4-Nitro-thiobenzamidato]mercury(II) Complexes

Several preparative routes to bis[N(substituted-phenyl) 4-nitro-thiobenzamidato] mercury(II) complexes are presented, including the reaction of mercury(II) oxide, fluoride, chloride, bromide, cyanide, acetate, and nitrate with N(substituted-phenyl) 4-nitro-thiobenzamide derivatives. ¹ H-NMR, Raman, and IR measurements confirmed the complexation of mercury to sulphur.     

Oscillometric titration of inorganic halides with mercury(II) acetate

Summary The difference between the relative ion mobility of the acetate and halide ions, and the well known slight dissociation of the mercury halides can be used for the titrimetric determination of the inorganic chlorides, bromides and iodides with oscillometric determination of the end-point. Errors in the determination of various halogenides were between 0,2 and 1,4%.

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Oscillometrische Titration von anorganischen Halogeniden mit Quecksilber(II)-acetat

Zusammenfassung Der Unterschied zwischen der relativen Ionenbeweglichkeit der Acetat- und Halogenidionen und die bekannte geringe Dissoziation der Quecksilberhalogenide wurde zur volumetrischen Bestimmung von anorganischen Chloriden, Bromiden und Jodiden mit oscillometrischer Endpunktsanzeige verwendet. Die Fehler bei der Bestimmung verschiedener Halogenide lagen zwischen 0,2 und 1,4%.

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Communicated at the 2nd Conference on Applied physical Chemistry in Veszprém on August 2–5, 1971.     

Study of the interaction of Lewis bases with mercury(II) chloride and mercury(II) acetate by mercury-199 NMR

The mercury-199 NMR spectra of mercury(II) chloride and mercury(II) acetate in the presence of amines and sulfides in DMSO were recorded. The structure of the coordination compounds is discussed.     

Practical synthesis of 6-aryluridines via palladium(II) acetate catalyzed Suzuki-Miyaura cross-coupling reaction

Sugar-protected 6-halouridine derivatives underwent Suzuki-Miyaura cross-coupling reactions with arylboronic acids in the presence of palladium(II) acetate as a catalyst, triphenylphosphine as a ligand, and sodium carbonate as a base. This methodology is applicable to both the C5- and C6-position of uridine and provides a direct access for versatile uridine derivatives.     

The synthesis of mesoporous aluminosilicate using microcline for adsorption of mercury(II)

An economical mesoporous aluminosilicate was synthesized with microcline as starting material and the precursor 13X zeolite as seed for crystal structure on mesoporous walls. In this method, a mixture of microcline and Na2CO3 with a molar ratio of 1:1.05 was first calcined at 1093 K for 2.5 h. The calcined materials were mixed with 35 ml C16TMABr aqueous solution (containing 8.2 g C16TMABr) and the precursors of 13X zeolite, resulting in mesoporous aluminosilicate after crystallization of the solution at 378 K for 48 h and calcination of the powder at 823 K for 5 h. The as-synthesized sample has a uniform pore diameter distribution centered at 3.7 nm. The as-synthesized sample had BET surface area of 725 m2/g and BJH mean pore diameter of 3.7 nm. The FT-IR results revealed that the building units of 13X zeolite were inserted into the pore walls of the as-synthesized sample. The adsorption ratio of mercury(II) onto the as-synthesized adsorbent was about 95%. The adsorption process was found to be spontaneous and can be explained by particle diffusion and chemical ion-exchange mechanisms. The equilibrium concentration of mercury(II) using the as-synthesized sample as the adsorbent was under 1 microg/L, making the concentration of mercury meet the limit for drinking water in China as recommended by the World Health Organization.     

Zinc(II), cadmium(II) and mercury(II) complexes of 4-amino-benzophenone

The following zinc(II), cadmium(II) and mercury(II) complexes of 4-amino-benzophenone (L) have been prepared and studied by i.r. and electronic spectra: 2MX₂·3L (M=Zn, Cd; X=Cl, Br), 3ZnI₂·2L, 2ZnI₂·L, MX₂·L (M=Cd, X=I; M=Hg, X=Cl, Br). Infrared spectra show that in the zinc complexes the ligand is principally bonded through the aminic nitrogen atom and in the cadmium and mercury(II) complexes through the carboxylic oxygen atom.     

Novel mercury (II) ion-selective polymeric membrane sensor based on ethyl-2-benzoyl-2-phenylcarbamoyl acetate

Mercury (II) ion-selective PVC membrane sensor based on ethyl-2-benzoyl-2-phenylcarbamoyl acetate (EBPCA) as a novel nitrogen containing sensing material is successfully developed. The sensor exhibits good linear response of 30 mV per decade within the concentration range 10(-6)-10(-3) mol l(-1) Hg(II). The sensor shows good selectivity for mercury (II) ion in comparison with alkali, alkaline earth, transition and heavy metal ions. The EBPCA-based sensor is suitable for use with aqueous solutions of pH 2.0-4.5 and exhibits minimal interference by Ag(I) and Fe(III), which are known to interfere with other previously suggested sensors. The nature and composition of the sensing material and its mercury complex are examined using Fourier-transform infrared analysis, elemental analysis and X-ray fluorescence techniques. The proposed sensor is applied as a sensor for the determination of Hg(II) content in some amalgam alloys. The results show good correlation with data obtained by atomic absorption spectrometric method.     

One-step synthesis of 3-aryl- and 3,4-diaryl-(1H)-pyrroles using tosylmethyl isocyanide (TOSMIC)

A one-step synthesis of 3-aryl and 3,4-diaryl-(1H)-pyrroles from TOSMIC and commercially available or readily synthesized arylalkenes is reported. Optimal conditions were found to be NaOtBu in DMSO. The methodology was particularly efficient (yields > 65%) when electron poor aryl groups were attached to the alkene.[ reaction: see text]     

Direct synthesis of furans by 3 + 2 cycloadditions between rhodium(II) acetate stabilized carbenoids and acetylenes

Whan appropriate substituents are used, rhodium(II) acatate catalyzed decomposition of diazocarbonyls in the presence of acetylenes results in the formation of furans, derived from dipolar intermediates.     

Synthesis of N-unsubstituted 1,2,3-triazoles via aerobic oxidative N-dealkylation using copper(II) acetate

A copper-catalyzed aerobic oxidative CN bond cleavage reaction was developed for the synthesis of 4-substituted-NH-1,2,3-triazoles. Diverse β-ketotriazoles derivatives, which are the starting materials for the aerobic oxidative CN bond cleavage reaction, were prepared from nine aryl and seven alkyl alkynes and α-azidoacetophenone by a copper(I)-catalyzed [3 + 2]cycloaddition reaction. The aerobic oxidation of α-(1,2,3-triazol-1-yl)acetophenones using a catalytic amount of copper(II) acetate in the presence oxygen under neutral conditions gave the title compounds in high yield.     

Zinc (II), cadmium (II) and mercury (II) complexes of 2-methyl-benzothiazole

The following zinc (II), cadmium (II) and mercury (II) complexes of 2-methyl-benzothiazole (2Mebt=L) have been prepared and studied by conductometric methods, i.r. and Raman spectra: ML₂ (M = Zn, X = Cl, I, NO₃; M = Cd, X = NO₃, ClO₄; M = Hg, X = NO₃), ML_1.5X₂ (M = Zn, X = ClO₄ (H₂O); M = Hg, X = ClO₄) and MLX₂ (M = Cd and Hg, X = Cl, Br, I). The ligand is N-bonded when acting as monodentate and N,S-bonded as bridging ligand. The halide, nitrate and perchlorate ions are coordinated.