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91.
Salman R. Salman Gazi A. W. Derwish Sabri M. H. Al-Marsoumi 《Journal of inclusion phenomena and macrocyclic chemistry》1995,23(3):175-179
The intermolecular charge transfer complexes (CT) of two crown ethers (CE), viz, B15C5 and DB18C6 (as donors), and tetracyanoethylene (TCNE), as acceptor, were studied in the UV-visible region in dichloroethane (DCE), at 298.2 K. The sequence of addition of the cation was varied in the case of B15C5 such that in one system the sequence was (CE+Cation)+TCNE and in the other (CE+TCNE)+cation. These two systems were found to be non-interchangeable, even under reflux conditions, giving differentK
c
values which were explained as being due to the different geometries of the CE. For the first sequence, the values most affected depended on the fit of the metal cation with the ether cavity, thus in B15C5, Na+ showed the greatest effect, while for DB18C6 it was K+. 相似文献
92.
A template synthesis procedure yielded [Ni(HL1)NH3]I, where HL1 is the monoanion of the terdentate ONN benzoylacetone S-methylisothiosemicarbazone ligand. The reaction of this complex with an excess of NH4NCS, pyridine, or hydrazine resulted in the complexes [Ni(HL1)(NH3)NCS] and [Ni(L1)A] (A = Py, N2H4). The monoanionic form of the ligand is obtained by deprotonation of the enolic form of the benzoylacetone moiety, whereas the dianion is formed by additional deprotonation of the terminal NH2 group. Finally, the reaction of [Ni(HL1)NH3]I with salicyladehyde produced the NiL2 complex in which L2 stands for the dianion of the ONNO ligand N(1)-2-butylidene-4-oxo-4-phenyl-N(4)-salicylidene-S-methylisothiosemicarbazide. All complexes are diamagnetic and have a square-planar configuration, except for [Ni(HL1)(NH3)NCS], for which te data of i.r. spectra suggest a square-pyramidal structure. The electronic absorption spectra of the ethanolic solutions of all complexes are characteristic of typical square-planar coordination of nickel(II). 相似文献
93.
Two chromogenic monoaza crown ethers were synthesized and investigated for their lithium extraction capabilities. The chromogenic monoaza 14-crown-4 compound exhibited the best selectivity for lithium over sodium; ca. 2800, with a detection limit of 0.08 ppm. 相似文献
94.
Crystal Structure of the “Supramolecular” Complex [Cs2(18-crown-6)][HgI4] with Unusually Coordinated Cs Ions The reaction of 18-crown-6, 1,4,7,10,13,16-hexaoxacyclooctadecane, with HgI2/CsI in methanol yields crystals of [Cs2(C12H24O6)][HgI4]. The compound crystallizes monoclinically, space group P21/c, Z = 4, a = 1574.8(3), b = 1067.0(3), c = 1693.2(6) pm, and β = 98.29(3)º. The structure consists of a network made up of two different types of [Cs-(18-crown-6)-Cs]2+ cations, interconnected by [HgI4]2? anions. The cations form an “anti-sandwich” structure with relatively short Cs ? Cs distances of 382 pm in the first type of cations and a longer distance of 480 pm in the second type of cations. 相似文献
95.
Reaction of Tin Chlorides with Polysulfides. Crystal Structures of (PPh4)2[SnCl2(S6)2], (PPh4)2[Sn4Cl4S5(S3)O], and (PPh4)2[SnCl6] · S8 · 2CH3CN . The reaction of PPh4[SnCl3] with Na2S4 in acetonitrile in the presence of small amounts of water yields (PPh4)2[Sn4Cl4S5(S3)O] and minor amounts of (PPh4)2[SnCl2(S6)2], PPh4Cl · 2S8 and (PPh4)2[SnCl6]. SnCl4 is partially reduced by (PPh4)2Sx, PPh4[SnCl3] and (PPh4)2[SnCl6] · S8 · 2CH3CN being produced. According to the X-ray crystal structure determination the [Sn4Cl4S5(S3)O]2?-ion consists of an O atom that is coordinated by four Sn atoms which in turn are liked with one another by five single S atoms and one S3 group. In the [SnCl2(S6)2]2?-ion the Sn atom is octahedrally coordinated by two Cl atoms in trans arrangement and by two chelating S6 groups. Octahedral [SnCl6]2? ions and S8 molecules in the crown conformation are present in (PPh4)4[SnCl6] · S8 · 2CH3CN. 相似文献
96.
Liquid-liquid-liquid phase microextraction (LLLME) coupled with high-performance liquid chromatography (HPLC) for the analysis of some aromatic amines is described. These compounds were extracted from 4.0 mL aqueous sample that adjusted to pH 13 with, NaOH-NaCl buffer solution (donor phase, P1) into an organic phase (P2) 150 μl benzyl alcohol and ethyl acetate (2:1) and then back extracted into a microdrop of aqueous acceptor phase (P3), adjusted at pH 2, with Na2HPO4-H3PO4 buffer solution. The extraction time, T1 (from P1 to P2) was 20 min and T2 (from P2 to P3) was 1 min. Different crown ethers as complexing agents for amines were added to the acceptor phase to improve the extraction time. Factors such as organic solvents, extraction times, and addition of crown ethers to acceptor phase and stirring rate were optimised. The method was applied for determination of aromatic amines in wastewater samples. Enrichment factors ranged from 184.5 to 389.7. The linearity range was from 3 to 1000 ng/ml and the detection limits varied from 0.8 to 1.80 ng/ml. Relative standard deviations (%, n = 5) were found (at S/N 3) in the range of 1.9 to 10.1. All experiments were carried out at room temperature, 22 ± 0.5 °C. 相似文献
97.
A new method for the simultaneous determination of anions (sulfate, nitrate, and chloride) and cations (sodium, ammonium, potassium, magnesium, and calcium) in acid rain waters was investigated using high-performance ion-exclusion/cation-exchange chromatography with conductimetric detection on a separation column packed with a polymethacrylate-based weakly acidic cation-exchange resin in the hydrogen-form and an eluent comprising 1.5 mM sulfosalicylic acid–6 mM 18-crown-6 at pH 2.6, operated at 1.5 ml/min. Effective separation and highly sensitive conductimetric detection for the anions and the cations was achieved in about 14 min. Since the ionic balance (equivalents of anions/equivalents of cations) of acid rain waters of different pH (4.40–4.67) ranged from 0.97 to 0.94, evaluation of the water quality of acid rain was possible. This method was successfully applied to the simultaneous determination of the anions and the cations in acid rain transported from mainland China and North Korea to central Japan monitored by a meteorological satellite data analyzer. 相似文献
98.
Pseudohalogeno Metal Compounds. LXXV. Pentacarbonylrhenium and Triphenylphosphinegold Complexes of Pseudohalide Anions: (OC)5ReX, Ph3PAuX (x = ONC(CN)2, o-MeC6H4SO2C(CN)2, o-MeC6H4SO2NCN, Ph2(S)PNCN) The pseudohalides (X?) nitrosodicyanmethanide, o-tosyldicyanmethanide, o-tosylcyanamide and diphenylthiophosphinylcyanamide react with the Organometallic Lewis Acids (OC)5Re+ (as (OC)5ReFBF3) and Ph3PAu+ (as Ph3PAuNO3) to give the neutral title complexes (OC)5Re—X and Ph3PAu? X, respectively. X-ray diffraction shows that nitroso-dicyanmethanide is coordinated through the nitroso N-atom to the Re(CO)5 fragment. Cyanide-N-coordination is observed for the complexes with o-tosyldicyanmethanide and o-tosylcyanamide whereas diphenylthiophosphinylcyanamide is S-coordinated to the gold atom. Spectroscopic data (IR, NMR) of 1–6 are described. 相似文献
99.
Jeng-Shong Shih 《中国化学会会志》1994,41(3):309-314
Artificial macrocyclic polyethers were synthesized and applied as neutral carriers for ion-selective PVC membrane electrodes, ion-chromatographic packing materials, extractants and adsorbents for ion separation, coating materials for piezoeletrical membrane sensors for organic species, and ion-transport carriers through liquid membranes. Ion-selective electrodes such as those for K+ Na+, UO22+, Cs+, Pb2+, Fe3+, Hg2+ and Ag+ ions based on crown ether-phosphotungstic acid (PW) precipitates and dithio crown ethers respectively were prepared and showed good sensitivity and selectivity. Crown ether-PW precipitates were applied as adsorbents of rare-earth ions and some common heavy-metal ions. Some rare-earth ions were easily extracted with crown ethers, especially 15-crown-5. Poly(stytene/divinyl benzene) cryptand-22 resin was synthesized and applied as a bifunctional stationary phase of ion chromatography to separate bom cations and anions, even some organic carboxylate geometric isomers. Crown ethers such as mono-benzo-15-crown-5 was successfully applied as a coating material on piezoelectric quartz membrane sensors for some organic species. The oscillation frequency of the crown-ether quartz-membrane sensor was sensitive to organic vapours such as amines and alcohols. Upon adsorption of organic species on the crown-ether quartz membrane, the oscillation frequency of the sensor decreased obviously. Special crown ether such as dibenzo-16-crown-5-oxyacetic acid, decyl-cryptand-22 and 1, 4-dihydro-pyridine-18-crown-5 were synthesized and successfully applied as ion-transport carriers (ionophores) for transport of Na+ K+ and Mg2+ ions through liquid membranes. 相似文献
100.
Hella Folkerts Kurt Dehnicke Jrg Magull Helmut Goesmann Dieter Fenske 《无机化学与普通化学杂志》1994,620(7):1301-1306
Phosphorane Iminato-Trichloroselenates(II): Syntheses and Crystal Structures of [SeCl(NPPh3)2]+SeCl3? and [Me3SiN(H)PMe3]2+[Se2Cl6]2? [SeCl(NPPh3)2]+SeCl3? has been synthesized by the reaction of Se2Cl2 with Me3SiNPPh3 in acetonitrile solution, forming orangered crystals, whereas red crystals of [Me3SiN(H)PMe3]2+[Se2Cl6]2? were obtained by the reaction of Me3SiNPMe3 with SeOCl2 in acetonitrile solution. Both complexes were characterized by X-ray structure determinations. [SeCl(NPPh3)2]+SeCl3?: Space group P21/n, Z = 4, structure solution with 7 489 observed unique reflections, R = 0.057. Lattice dimensions at ?60°C: a = 1 117.0; b = 2 241, c = 1 407.5 pm, β = 95.61°. In the cation [SeCl(NPPh3)2]+ the selenium atom is φ-tetrahedrally coordinated by the chlorine atom and by the nitrogen atoms of the phosphorane iminato ligands, whereas the anion SeCl3? has a T-shaped structure with φ-trigonal-bipyramidale surrounding of the selenium atom. [Me3SiN(H)PMe3]2+[Se2Cl6]2?: Space group P21/c, Z = 4, structure solution with 2 093 observed unique reflections, R = 0.080. Lattice dimensions at ?70°C: a = 956, b = 828, c = 1 973 pm, β = 93.80°. The structure consists of [Me3SiN(H)PMe3]+ ions and planar [Se2Cl6]2? anions, in which the selenium atoms are bridged nearly symmetrically by two chlorine atoms. 相似文献