碘化物-结晶紫-聚乙烯醇体系分光光度法测定自来水中痕量二氧化氯

在稀磷酸介质中，二氧化氯（ＣｌＯ２）氧化Ｉ离子形成 Ｉ３配阴离子，Ｉ３进一步与结晶紫（ＣＶ）阳离子形成离子缔合物［ＣＶ］［Ｉ３」。在聚乙烯醇存在下，该离子缔合物最大吸收波长λｍａｘ位于５５２ ｎｍ处，摩尔吸光系数ε＝２５ × １０５Ｌ·ｍｏｌ－１·ｃｍ－１，对 ＣｌＯ２的检出限为 ０．６ μｇ／Ｌ，线性范围是 ０．６～２８０μｇ／Ｌ。加入适量 ＫＦ溶液可消除自来水中Ｆｅ（Ⅲ）的干扰。方法对μｇ／Ｌ级ＣｌＯ２ 的测定有较好的选择性，可成功地用于自来水样品分析。     

压电石英晶体在电解质水溶液中的振荡性能研究(Ⅱ)——频率、频移特性

根据两面电极浸入液体中的压电晶体等效电路模型和Pierce振荡器振荡方程的解,得到晶体在电解质溶液中的振荡频率(F_1)与溶液电导率(x)的关系式:F_1=(1/2π)(1/C_1+1/C_2)(1/X_e)[(R_e~2+X_e~2)x~2+2R_ex+1]。以自行设计的Pierce晶体振荡器。研究了晶体和主振电路参数、输入电压及检测池外壳屏蔽接地对AT切9MHz石英晶体在KCl、Na_2SO_4水溶液中的频率、相对于纯水频移随溶液电导率变化的影响规律,结果与上式相符。     

Crystal and Molecular Structure of Quinide

ＣｒｙｓｔａｌａｎｄＭｏｌｅｃｕｌａｒＳｔｒｕｃｔｕｒｅｏｆＱｕｉｎｉｄｅＷＡＮＧＧａｎｇ－Ｌｉ；ＺＨＡＯＳｈｕ－Ｊｉｅ；ＣＨＥＮＤｅ－Ｃｈａｎｇ（ＮａｔｉｏｎａｌＩｎｓｔｉｔｕｔｅｆｏｒｔｈｅＣｏｎｔｒｏｌｏｆＰｈａｒｍａｃｅｕｔｉｃａｌａｎｄＢｉ...     

液晶性芳香酰胺化合物的合成

合成了一系列炖粹以酰胺基为中心桥键的刚性芳香酰胺小分子化合物，并对其作了表征，发现其中有些化合物具有液晶性。酰胺键之间能形成很强的分子间氢键，使芳香酰胺小分子化合物的熔点很高，难于形成液成液晶态。研究发现，如果在这类化合物的中心苯环上引入合适的取代基以减弱分子间氢键，同时引入合适的末端基时，则可使芳香酰胺化合物生成液晶相的能力增强。     

Na2B2Se7, K2B2S7 und K2B2Se7: Drei Perchalkogenoborate mit neuem polymeren Anionengerüst

Na₂B₂Se₇, K₂B₂S₇, and K₂B₂Se₇: Three Perchalcogenoborates with a Novel Polymeric Anion Network Na₂B₂Se₇ (I 2/a; a = 11.863(4) Å, b = 6.703(2) Å, c = 13.811(6) Å, β = 109.41(2)°; Z = 4), K₂B₂S₇ (I 2/a; a = 11.660(2) Å, β = 6.827(1) Å, c = 12.992(3) Å, β = 106.78(3)°; Z = 4), and K₂B₂Se₇ (I 2/a; a = 12.092(4) Å, b = 7.054(2) Å, c = 13.991(5) Å, β = 107.79(3)°; Z = 4) were prepared by reaction of stoichiometric amounts of sodium selenide (potassium sulfide) with boron and sulfur or of potassium selenide and boron diselenide, respectively, at 600°C with subsequent annealing. The crystal structures consist of polymeric anion chains of composition ([B₂S₇]^2?)_n or ([B₂Se₇]^2?)_n formed by spirocyclically connected five-membered B₂S₃ (B₂Se₃) rings and six-membered B₂S₄ (B₂Se₄) rings. The nine-coordinate alkaline metal cations are situated in between.     

X-ray study of volatile Ni(II), Cu(II), and Pd(II) complexes of β-ketoimine pivalyltrifluoroacetone

Synthesis of volatile complexes based on -ketoimine pivalyltrifluoroacetone, C(CH₃)₃C(NH)CH₂COCF₃, is described. The general formula of the complexes is M(L)₂, where M = Cu, Ni, Pd. Complexes of this kind with Ni and Pd were obtained for the first time. The Cu and Pd complexes were found to be isostructural. A comprehensive crystal-chemical study showed that all structures are molecular and built of trans-complexes. The central atom has a square plane environment. The average M-O and M-N distances are nearly equal in all compounds: 1.84 , 1.92 , and 1.98 for Ni, Cu, and Pd complexes, respectively; the mean values of the O-M-N chelate angles are 93.4°, 91.9°, and 92.7°, respectively.Original Russian Text Copyright © 2004 by I. A. Baidina, G. I. Zharkova, N. V. Pervukhina, S. A. Gromilov, and I. K. IgumenovTranslated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 4, pp. 713–722, July–August, 2004.This revised version was published online in April 2005 with a corrected cover date.     

Synthesis, Structure and Conductivity of the New Charge-transfer Salt (ET)_2(CH_2=CH-CH_2-SO_3)·H_2O

ET is one of the most famous electron-donor molecules, which forms charge-transfer complexes (abbr. CT-complexes) with various types of counterions. These complexes have received intense attention because a wide range of physical properties such as conductivity and superconductivity1, ferromagnetism2-4 and nonlinear optical properties5 was found in these materials. Although the majority of the ET-based CT-complexes were prepared by combining with inorganic counterions, CT-complexes with o…     

One-dimensional Infinite Chain Organotin Compounds: Synthesis and Structural Characterization of Triphenyltin Thiazole-2-carboxylate and Triphenyltin 3-Pyridinylcarboxylate

ＩｎｔｒｏｄｕｃｔｉｏｎＯｒｇａｎｏｔｉｎｃａｒｂｏｘｙｌａｔｅｓａｒｅｗｉｄｅｌｙｕｓｅｄａｓｂｉｏｃｉｄｅｓ ,ｆｕｎｇｉｃｉｄｅａｎｄａｓｈｏｍｏｇｅｎｅｏｕｓｃａｔａｌｙｓｔｓｉｎｉｎｄｕｓｔｒｙ .1 6Ｉｎｏｒｄｅｒｔｏｅｘｐｌｏｒｅｔｈｅｒｅｌａｔｉｏｎｓｈｉｐｓｂｅｔｗｅｅｎｂｉｏｌｏｇｉｃａｌａｃｔｉｖ ｉｔｙａｎｄｓｔｒｕｃｔｕｒｅ ,ａｎｕｍｂｅｒｏｆｓｕｃｈｍｏｌｅｃｕｌｅｓｈａｖｅｂｅｅｎｓｙｎｔｈｅｓｉｚｅｄａｎｄｓｔｕｄｉｅｄｉｎｒｅｃｅｎｔｙｅａｒｓ .7 15Ｓｔｕｄｉｅｓｏｎ…     

Polyhedral clathrate hydrates of a strong base: Phase relations and crystal structures in the system tetramethylammonium hydroxide-water

The tetramethylammonium hydroxide-water system has been studied by low-temperature differential thermal analysis and X-ray powder diffraction. The melting diagram was constructed for concentrations between 66.7 and 100 mol% H₂O. It shows the existence and stability ranges of as many as eight crystalline hydrate phases:- and-Me₄NOH·2H₂O (phase transition at –85°C, decomposition atca. 105°C), Me₄NOH·4 H₂O (melting point 44°C, incongruent), and-Me₄NOH·5 H₂O (phase transition at 42°C, melting point 68°C, congruent),- and-Me₄NOH·7.5 H₂O (phase transition at 6°C, melting point 16°C, incongruent), and Me₄NOH·10 H₂O (melting point –20°C, incongruent). The structures of all these phases, except the already known one of-Me₄NOH·5 H₂O, were determined from single-crystal MoK diffractometer data. The decahydrate and the high-temperature forms of the 7.5-hydrate and the pentahydrate are genuinepolyhedral clathrate hydrates, the first ones reported of a strong base. Their mostly novel three-dimensional anionic host structures, formed by the hydrogen-bonded OH^– ions and H₂O molecules, arefour-connected throughout, in spite of their proton deficiency which is apparently leveled by disorder. Disorder also affects the enclosed cationic Me₄N⁺ guest species. Like the low-temperature form of the pentahydrate, that of the 7.5-hydrate has a clathrate-related, but not fully polyhedral structure, some of the oxygen atoms being three-connected only. The tetrahydrate presents the rare case of both a hydrogen bond of the type OH^–...OH₂ and a (deprotonated) water-channel structure. This is fully ordered and apart from that can be derived from the polyhedral one of the-pentahydrate just by removing the appropriate number of water molecules from certain positions. The structures of- and-Me₄NOH·2 H₂O contain identical one-dimensionalspiro chains [HO^–(HOH)_/42] with the hydroxide protonnot participating in the hydrogen bonding. The Me₄N⁺ ion is ordered in the and disordered in the phase.Supplementary Data relating to this article are deposited with the British Library as Supplementary Publication No. SUP 82076 (66 pages).Dedicated to Dr D. W. Davidson in honor of his great contributions to the sciences of inclusion phenomena.     

Darstellung,Ramanspektren und Kristallstrukturen von V2O3(SO4)2, K[VO(SO4)2] und NH4[VO(SO4)2]

Preparation, Raman Spectra, and Crystal Structures of V₂O₃(SO₄)₂, K[VO(SO₄)₂], and NH₄[VO(SO₄)₂] The oxo-sulfato-vanadates(V) V₂O₃(SO₄)₂, K[VO(SO₄)₂], and NH₄[VO(SO₄)₂] have been prepared as crystals suitable for X-ray structure determination. In all structures sulfate acts as an unidentate ligand only toward a single vanadium atom. The structure of V₂O₃(SO₄)₂ consists of a threedimensional network of pairs of cornershared VO₆ octahedra with one terminal oxygen atom each, and SO₄ tetrahedra. All oxygen atoms of the sulfate ions are coordinated. NH₄[VO(SO₄)₂] and K[VO(SO₄)₂] are isostructural. VO₆ octahedra with one terminal oxygen atom and pairs of sulfate tetrahedra form infinite chains by corner sharing. The chains are weakly interlinked to layers. The sulfate ions are distorted towards planar SO₃ molecules and single oxygen atoms attached to vanadium. This structural detail gives an explanation for the mechanism of the reversible reaction K[VO(SO₄)₂] ? K[VO₂(SO₄)] + SO₃ at 400°C. Raman spectra of the compounds have been recorded and interpreted with respect to their structures. Crystal data: V₂O₃(SO₄)₂, monoclinic, space group P2₁/a, a = 947.2(4), b = 891.3(3), c? 989.1(4) pm, β = 104.56(3)°, Z = 4, 878 unique data, R(R_w) = 0.039(0,033); K[VO(SO₄)₂], orthorhombic, space group P2₁2₁2₁, a = 495.3(2), b = 869.6(9), c = 1 627(1)pm, Z = 4, 642 unique data, R(R_w) = 0,11(0,10); NH₄[VO(SO₄)₂], orthorhombic, space group P2₁2₁2₁, a = 495.3(1), b = 870.0(2), c = 1 676.7(4)pm, Z = 4, 768 unique data, R(R_w) = 0.088(0.083).