进样阀(I)

高效液相色谱进样阀（或进样器）的作用是将一定量的样品送入色谱仪。样品在流动相的带动下进入色谱柱系统完成分离过程。现代高效液相色谱仪对于进样阀的要求如下：（１）耐高压,因为高效液相色谱通常要在３５．０ＭＰａ或更高的压力下工作;（２）进样量精确;（３）进样重复性好;（４）方便、适用,且可根据需要选择不同的进样量;（５）价格低廉;（６）保证在色谱柱中心进样,操作时不产生流量或压力波动。到目前为止,液相色谱进样阀共有３种形式：１．手动注射进样器;２．手动进样阀;３．自动进样器。从原理上讲,自动进样器是在…     

Acidity constants in different media (I=0 and I=0.1 M KCl) from the uncertainty perspective

Procedures for estimating the measurement uncertainty for the acidity constant Ka (or the pKa value) in different media (I=0 and I=0.1 mol L(-1) KCl), as determined by potentiometric titration, are presented. The uncertainty budgets (the relative contributions of the different input quantities to the uncertainty in the result) of the pKa (I=0) and pKa (I=0.1 mol L(-1) KCl) values are compared. Unlike the values themselves, the uncertainties and uncertainty budgets of the values are comparable. The uncertainty estimation procedures are based on mathematical models of pKa measurement and involve the identification and quantification of individual uncertainty sources according to the ISO GUM approach. The mathematical model involves 52 and 48 input parameters for pKa (I=0) and pKa (I=0.1 mol L(-1) KCl), respectively. The relative importance of each source of uncertainty is discussed. In both cases, the main contributors to the uncertainty budget are the uncertainty components due to the hydrogen ion concentration/activity measurement, which provide 63.7% (for pKa (I=0)) and 89.3% (for pKa (I=0.1 mol L(-1) KCl)) of the uncertainty. The remaining uncertainty contributions arise mostly from the limited purity of the acid. From this work, it is clear that the uncertainties of the pKa (I=0.1 mol L(-1) KCl) values tend to be lower than those of the pKa (I=0) values. The main reasons for this are that: (1) the uncertainty due to the residual liquid junction potential is nominally absent in the case of pKa (I=0.1 mol L(-1) KCl) due to the similarly high concentrations of background electrolyte in the calibration solutions and measured solution; (2) the electrode system is more stable in solutions containing the 0.1 mol L(-1) KCl background electrolyte and so the readings obtained in these solutions are more stable.     

Tunability of the M(II)M(III)/M(II)(2) and M(III)(2)/M(II)M(III) (M=Mn, Co) couples in bis-μ-O,O'-carboxylato-μ-OR bridged complexes

A comparison of the electrochemical properties of a series of dinuclear complexes [M(2)(L)(RCO(2))(2)](+) with M = Mn or Co, L = 2,6-bis(N,N-bis-(2-pyridylmethyl)-sulfonamido)-4-methylphenolato (bpsmp(-)) or 2,6-bis(N,N-bis(2-pyridylmethyl)aminomethyl)-4-tert-butylphenolato (bpbp(-)) and R = H, CH(3), CF(3) or 3,4-dimethoxybenzoate demonstrates: (i) The electron-withdrawing sulfonyl groups in the backbone of bpsmp(-) stabilize the [M(2)(bpsmp)(RCO(2))(2)](+) complexes in their M(II)(2) oxidation state compared to their [M(2)(bpbp)(RCO(2))(2)](+) analogues. Manganese complexes are stabilised by approximately 550 mV and cobalt complexes by 650 mV. (ii) The auxiliary bridging carboxylato ligands further attenuate the metal-based redox chemistry. Substitution of two acetato for two trifluoroacetato ligands shifts redox couples by 300-400 mV. Within the working potential window, reversible or quasi-reversible M(II)M(III)? M(II)(2) processes range from 0.31 to 1.41 V for the [Co(2)(L)(RCO(2))(2)](+/2+) complexes and from 0.54 to 1.41 V for the [Mn(2)(L)(RCO(2))(2)](+/2+) complexes versus Ag/AgCl for E(M(II)M(III)/M(II)(2)). The extreme limits are defined by the complexes [M(2)(bpbp)(CH(3)CO(2))(2)](+) and [M(2)(bpsmp)(CF(3)CO(2))(2)](+) for both metal ions. Thus, tuning the ligand field in these dinuclear complexes makes possible a range of around 0.9 V and 1.49 V for the one-electron E(M(II)M(III)/M(II)(2)) couple of the Mn and Co complexes, respectively. The second one-electron process, M(II)M(III)? M(III)(2) was also observed in some cases. The lowest potential recorded for the E°(M(III)(2)/M(II)M(III)) couple was 0.63 V for [Co(2)(bpbp)(CH(3)CO(2))(2)](2+) and the highest measurable potential was 2.23 V versus Ag/AgCl for [Co(2)(bpsmp)(CF(3)CO(2))(2)](2+).     

Metalloligand-induced Synthesis of Two Cu(I)–M (M=Ni,Co) Heterobimetallic Coordination Polymers: Structures,Thermal and Luminescence Properties

Two interesting heterobimetallic coordination polymers (CPs), {[Ni(4-pytpy)₂]₂[Cu₄(N(CN)₂)₇](NO₃)(DMF)(DMSO)(H₂O)₄}_n (1) and {[Co(4-pytpy)(N(CN)₂)]₂[Cu₂(N(CN)₂)₄]}_n (2), have been synthesized based on different metalloligands [M(4-pytpy)₂]²⁺ (M=Ni 1, Co 2) (4-pytpy = 4′-(4-pyridyl)-2,2′:6′,2″-terpyridine). CPs 1 and 2 have been well characterized by elemental analysis, IR spectroscopy, thermal analysis and single-crystal X-ray diffraction. Both CPs 1 and 2 crystallize in the triclinic crystal system with the P-1 space group but feature different structures. CP 1 exhibits a unique one dimensional double-chain structure, while CP 2 possesses an infinite 2D network structure. It is interesting to note that the metalloligand [Co(4-pytpy)₂]²⁺ in CP 2 was decomposed into [Co(4-pytpy)]²⁺. Thermal analysis indicates that the chain structure of CP 1 begins to collapse after about 360 °C, while CP 2 can be stable up to 300 °C. The solid-state luminescence properties of CPs 1 and 2 have also been investigated.     

伟大的分析化学家——I．M．Kolthoff

本文简介Ｋｏｌｔｈｏｆ的主要工作并初步探讨了他的学术、教育思想的某些特点     

Small Gold(I) and Gold(I)–Silver(I) Clusters by C−Si Auration

Auration of o-trimethylsilyl arylphosphines leads to the formation of gold and gold–silver clusters with ortho-metalated phosphines displaying 3c–2e Au−C−M bonds (M=Au/Ag). Hexagold clusters [Au₆L₄](X)₂ are obtained by reaction of (L−TMS)AuCl with AgX, whereas reaction with AgX and Ag₂O leads to gold–silver clusters [Au₄Ag₂L₄](X)₂. Oxo-trigold(I) species [Au₃O]⁺ were identified as the intermediates in the formation of the silver-doped clusters. Other [Au₅], [Au₄Ag], and [Au₁₂Ag₄] clusters were also obtained. Clusters containing PAu−Au−AuP structural motif display good catalytic activity in the activation of alkynes under homogeneous conditions.     

Nitridsulfidchloride der Lanthanide: I. Der Formeltyp M4NS3Cl3 (M = La?Nd)

Nitride Sulfide Chlorides of the Lanthanides. I. The Composition M₄NS₃Cl₃ (M = La Nd) The oxidation of the „light”︁ lanthanides (M = La Nd) with sulfur and NaN₃ the presence of the chlorides MCl₃ results in the formation of the first lanthanide nitride sulfide chlorides M₄NS₃Cl₃ when appropriate molar ratios of the reactants are used. The addition of some NaCl (or an excess of MCl₃) as a flux secures complete and fast reaction (7 d) at 850°C in evacuated silica vessels as well as single-crystalline products. Since these nitride sulfide chlorides (fine transparent needles) are not sensitive against hydrolysis, the surplus chloride can be removed easily with water. The crystal structure was determined from X-ray single crystal data for the example of La₄NS₃Cl₃ (hexagonal, P6₃mc (no. 186), Z = 2, a = 941.40(3), c = 700.36(3) pm, R = 0.026, R_w = 0.021) and the nitride sulfide chlorides M₄NS₃Cl₃ with M = Ce Nd proved to be isostructural from Guinier powder data. According to their Ba₃OCl₆-analogue structure, two crystallographically different M³⁺ cations are present (CN(M1) = 10, CN(M2) = 8). „Isolated”︁ tetrahedra [(N³⁻)(M³⁺)₄] build up the Mayn structural feature according to [NM₄]S₃Cl₃. They are hexagonally closest packed and interconnected via the crystallographically different but by X-ray diffraction indistinguishable anions S²⁻ and Cl⁻, which take care for charge neutrality.     

Étude structurale comparée des chromates: M(I)M(III)(CrO4)2; M(I) = Li+, Na+, K+, Rb+, Cs+, NH4+, Ag+ et Tl+; M(III) = Al3+, Fe3+, Cr3+, Tl3+ et Bi3+

Among compounds of formula type M(I)M(III)(CrO₄)₂, the structures of trivalent bismuth compounds are always different from the others, because the surrounding of bismuth is never well-defined. Besides, nearly all these compounds have two-dimensional structures with the exception of Tl(I)Tl(III)(CrO₄)₂ which is three-dimensional. This structural type can exist only when the ionic radius of the monovalent cation has a value near that of O²⁻ ion (1.40 Å), as for Rb⁺, NH₄⁺ and Tl⁺.     

三元体系MCl-M′Cl-HOAc(25℃)的研究(M,M′=K、Rb、Cs,M≠M′)

测定了25℃下KCl-RbCl-HOAc,KCl-CsCl-HOAc,RbCl-CsCl-HOAc三个体系的溶度数据,绘制了相应的相图以及分配图。第一个体系中只有一种固相存在,属于Roozeboom第Ⅰ型;后两个体系互溶性都有十分明鲜的裂隙,但比以水为溶剂的体系中的互溶性显著增强,二者均属Roozeboom第Ⅳ型。     

M. S. Tswett and the discovery of chromatography I: Early work (1899–1903)

Summary On the occasion of the 90th anniversary of the Warsaw lecture of M. S. Tswett representing the first report on the chromatographic technique, this two-part article outlines the evolution of the method. This part deals with Tswett's early work in 1899–1901 and his research in 1901–1903 leading to the lecture at Warsaw. The second part will deal with the fundamental twin papers of 1906, with his book of 1910, summarizing all his activities related to the investigation of plant pigments and to the development of chromatography, and with a few special questions related to Tswett's scientific activities in this field.Part II of this article will be published in the next month's issue ofChromatographia.     

Lumineszierende Cu(I)-, Ag(I)- und Tl(I)-Komplexe mit N-Butyl-N′-benzolsulfonylthioharnstoff- Tetra- und hexamere (ML)x-Cluster

Zusammenfassung Das Säureanion von N-Butyl-N-benzolsulfonylthioharnstoff (BuBsT) bildet mit Cu(I) einen lumineszierenden hexameren und einen nicht lumineszierenden tetrameren Cluster (Cu(BuBsT))_x; x=6, 4. Röntgenstrukturanalysen belegen für x=6 eine verzerrt oktaedrische und für x=4 eine verzerrt tetraedrische Anordnung der Cu-Atome. Die Liganden beider Cluster sind über den Thioharnstoff-Schwefel und den Sulfonamid-Stickstoff mit den Cu-Atomen verknüpft (S,N-Koordination). Jeweils ein Sulfonyl-Sauerstoffatom pro Ligand bildet eine intramolekulare Wasserstoffbrücke zu der NHC₄H₉-Gruppe der gleichen Ligandeinheit aus. Ag(BuBsT) tritt in Form von drei lumineszierenden Modifikationen auf, von denen eine (Ag(BuBsT)-II) hexamer ist (isotyp mit (Cu(BuBsT))₆). Tl(BuBsT) liegt in CHCl₃-Lösung überwiegend als Dimer vor.

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Luminescent Cu(I)-, Ag(I)- and TI(I)-complexes with N-Butyl-N-benzenesulfonylthiourea-tetramer and hexamer (ML)_x-clusters

Summary The acid anion of N-butyl-N-benzenesulfonylthiourea (BuBsT) forms numerous 1/1 complexes with the univalent ions Cu(I), Ag(I) and Tl(I). The crystal structures of two different copper(I) clusters (Cu(BuBsT))_x, (x=6, 4) are discussed. The hexamer containing a distorted Cu₆ octahedron is luminescent, while the analogous tetramer containing a distorted Cu₄ tetrahedron is not. The copper atoms of both clusters form coordinate linkages with the sulfonamide nitrogen and the thiourea sulphur of the ligands (S,N-coordination). One sulfonyl oxygen per ligand is bound to the NHC₄H₉ group of the same ligand through a hydrogen bond. Ag(BuBsT) forms three different luminescent modifications. One of them (Ag(BuBsT)-II) is isotype to (Cu(BuBsT))₆ and therefore hexamer, too. Tl(BuBsT) mainly forms dimers in CHCl₃ solution.

     

Self-assembled supramolecular M9 (Mn(II), Fe(III), Zn(II)), M5 (Fe(III)), and [M3]2 (Pb(II)) complexes: structural,magnetic, and Mössbauer properties

The tritopic ligand 2poap self-assembles in the presence of Zn(NO(3))(2) and Fe(NO(3))(3) to form homoleptic [3 x 3] nonanuclear M(9) (M = Zn(II), Fe(III)) square grid structures and with Pb(ClO(4))(2) to form a dimerized linear trinuclear [Pb(3)](2) structure. Cl2poap and Cl2poapz form self-assembled homoleptic [3 x 3] Mn(II)(9) square grids with Mn(ClO(4))(2) and Mn(NO(3))(2), respectively, but an unusual incompletely metalated Fe(III)(5) square grid is formed on reaction of Cl2poap with Fe(ClO(4))(3). X-ray structures are reported for [Mn(9)(Cl2poap-2H)(6)](ClO(4))(6).10H(2)O (3), [Mn(9)(Cl2poapz-2H)(6)] (NO(3))(6).22H(2)O (4), [Zn(9)(2poap-2H)(3)(2poap-H)(3)](NO(3))(9).24H(2)O (5), [Pb(3)(2poap-2H) (ClO(4))(4)](2).8H(2)O (6), and [Fe(5)(Cl2poap-H)(6)](ClO(4))(9).34.5H(2)O (7). Compound 3 crystallized in the monoclinic system, space group P(-)1, with a = 18.179(1) A, b = 18.857(1) A, c = 25.871(2) A, alpha = 70.506(2) degrees, beta = 86.440(1) degrees, gamma = 75.175(2) degrees, and z = 2. Compound 4 crystallized in the monoclinic system, space group P(-)1, with a = 16.900(2) A, b = 20.02393) A, c = 25.663() A, alpha = 84.743(3) degrees, beta = 84.885(2) degrees, gamma = 67.081(2) degrees, and z = 2. Compound 5 crystallized in the monoclinic system, space group P(-)1, with a = 18.482(1) A, b = 18.774(1) A, c = 28.112(2) A, alpha = 104.020(1) degrees, beta = 97.791(1) degrees, gamma = 117.036(1) degrees, and z = 2. Compound 6 crystallized in the monoclinic system, space group P(-)1, with a = 10.0513(6) A, b = 11.0958(6) A, c = 17.334(1) A, alpha = 100.932(1) degrees, beta = 100.387(1) degrees, gamma = 94.565(1) degrees, and z = 2. Compound 7 crystallized in the monoclinic system, space group P(-)1, with a = 19.164(1) A, b = 19.587(2) A, c = 26.673(2) A, alpha = 76.430(2) degrees, beta = 78.834(2) degrees, gamma = 64.973(1) degrees, and z = 2. Compound 3 exhibits intramolecular antiferromagnetic exchange within the nonanuclear [Mn(9)(mu-O)(12)] grid structure (J = -4.6 cm(-1)), while the analogous nonanuclear complex [Fe(9)(2poap-2H)(6)](NO(3))(15).18H(2)O (8) is dominated by intramolecular antiferromagnetic coupling at high temperatures but exhibits a low-temperature feature indicative of additional ferromagnetic interactions. The isolated pentanuclear Fe(5) [4 + 1] square grid in 7, with distant Fe-Fe bridging, exhibits very weak antiferromagnetic coupling (J = -0.2 cm(-1)). M?ssbauer spectroscopy data are consistent with high-spin Fe(III)(9) and Fe(III)(5) structures.     

Syntheses, structure, and a Mössbauer and magnetic study of Ba(4)Fe(2)I(5)S(4)

The compound Ba4Fe2I5S4 has been prepared at 1223-1123 K by the "U-assisted" reaction of FeS, BaS, S, and U with BaI2 as a flux. A more rational synthesis was also found; however, the presence of U appears to be essential for the formation of single crystals suitable for X-ray diffraction studies. Ba4Fe2I5S4 crystallizes in a new structure type with two formula units in space group I4/m of the tetragonal system. The structure consists of a Ba-I network penetrated by (1)infinity[Fe2S4] chains. Each Fe atom, which is located on a site with 4 symmetry, is tetrahedrally coordinated to four S atoms. The FeS4 tetrahedra edge-share to form linear (1)infinity[Fe2S4] chains in the [001] direction. The Fe-Fe interatomic distance in these chains is 2.5630(4) A, only about 3% longer than the shortest Fe-Fe distance in -Fe metal. Charge balance dictates that the average formal oxidation state of Fe in these chains is +2.5. The M?ssbauer spectra obtained at 85 and 270 K comprise a single quadrupole doublet that has hyperfine parameters consistent with an average Fe oxidation state of +2.5. The M?ssbauer spectrum obtained at 4.2 K consists of a single magnetic sextet with a small hyperfine field of -15.5 T. This spectrum is also consistent with rapid electron delocalization and an average Fe oxidation state of +2.5. The molar magnetic susceptibility of Ba4Fe2I5S4, obtained between 3.4 and 300 K, qualitatively indicates the presence of weak pseudo-one-dimensional ferromagnetic exchange within a linear chain above 100 K and weak three-dimensional ordering between the chains at lower temperatures.     

Cu(I),Ag(I)/分子筛化学吸附脱硫的π-络合机理

应用DFT研究了一系列含硫的杂环化合物(噻吩、苯并噻吩、二苯并噻吩和4,6-二甲基二苯并噻吩)以及苯分子在Cu(I)-Y、Ag(I)-Y分子筛上的化学吸附.计算采用16T分子筛簇模型(H22Si15AlO22),对过渡金属采用了赝势基组,在BLYP/DNP水平上完成.相互作用能的结果表明,阳离子交换的分子筛对含硫杂环芳香族化合物吸附能力的顺序为Cu(I)-Y>Ag(I)-Y.两种吸附剂对噻吩类分子的吸附能力大于苯分子.噻吩衍生物的吸附能顺序依次为,4,6-二甲基二苯并噻吩<二苯并噻吩<噻吩<苯并噻吩,与实验结果相近.通过自然键轨道计算,研究了分子筛上担载的Cu(I)、Ag(I)金属离子与噻吩和苯分子之间的π-络合作用,分析比较了自然键电子给体-受体之间的二阶微扰稳定化能,并探索其络合机理.     

Cu(I), Ag(I)/分子筛化学吸附脱硫的π-络合机理

应用DFT 研究了一系列含硫的杂环化合物(噻吩、苯并噻吩、二苯并噻吩和4, 6-二甲基二苯并噻吩)以及苯分子在Cu(I)-Y、Ag(I)-Y 分子筛上的化学吸附. 计算采用16T 分子筛簇模型(H22Si15AlO22), 对过渡金属采用了赝势基组, 在BLYP/DNP水平上完成. 相互作用能的结果表明, 阳离子交换的分子筛对含硫杂环芳香族化合物吸附能力的顺序为Cu(I)-Y >Ag(I)-Y. 两种吸附剂对噻吩类分子的吸附能力大于苯分子. 噻吩衍生物的吸附能顺序依次为, 4, 6-二甲基二苯并噻吩<二苯并噻吩约噻吩<苯并噻吩, 与实验结果相近. 通过自然键轨道计算,研究了分子筛上担载的Cu(I)、Ag(I)金属离子与噻吩和苯分子之间的π-络合作用, 分析比较了自然键电子给体-受体之间的二阶微扰稳定化能, 并探索其络合机理.     

127I MÖSSBAUER SPECTRA AND X-RAY CRYSTAL STRUCTURES FOR HYPERVALENT IODINE(III) COMPLEX OF HEXAFLUOROCUMYL ALCOHOL AND RELATED 10‐I‐3 COMPOUNDS

Abstract

The crystal structures of 1-chloro-3,3-bis(trifluoromethyl-1λ³,2(1H)-benzoiodoxole (I(hfpp)Cl) and 1-chloro-1λ³, 2-benzoiodoxole-3(1H)-one (I(ba)Cl) are determined. Although the T-shaped molecular structure for I(hfpp)Cl is quite similar to that for I(ba)Cl, the intermolecular interactions including the secondary bondings are significantly different; I(ba)Cl adopts an infinite chain structure with two longer I … O′ interactions, whereas I(hfpp)Cl has a dimeric structure with one I … O′ secondary bonding. The ¹²⁷I Mössbauer spectrum for I(hfpp)Cl is quite similar to those of hypervalent iodine(III) compounds having carboxylic and sulfonic ligands and chloride. This shows that the 5p electrons of the iodine(III) atom in I(hfpp)Cl are markedly withdrawn by apical oxygen and chlorine atoms almost equally, suggesting that the alcoholic oxygen atom of the ligand is quite electronegative.