2009Pittcon会议(Ⅱ)

传感器与传感整合系统组的报告有:(1)Ashvarev,应用脉冲电极作离子选择电极的无偏压选择性测定;(2)R de Marco,离子选择性原子X显微术--一种新的材料鉴定技术;(3)S P Kounares,应用离子选择性电极分析火星表面;(4)M DPietrazak,以Rh(Ⅲ)络合物为基础的选择性测定NO2-的电化与学光传感器;(5)E Baker,聚合物膜离子传感器的电化激发;(6)A Raclu,应用电化阻抗谱探测离子选择膜的功能性质与程度;(7)MGratzl,在活体民试管中进行以光极为基础的银传感器试验,应用于型小实验室中的动物代谢监测.     

2009Pittcon会议(Ⅰ)

本届会议于2009年3月8日至13日在美国芝加哥市召开,由G M Whitesides博士作题为纸诊断学的大会报告。首次举办的网络互动会议项目有:(1)试样制备以适应极低数量级的检测;(2)电分析的生物体气溶胶的选择性检测——利用还原氧化与电荷转移机理以满足实时、无试剂检测与合理成本的需     

Kinetics and mechanism of the anation of (αβ)-hydroxo(tetraethylenepentamine)cobalt(III) by thiosulfate, the base hydrolysis of the (sulfur-bonded) thiosulfato(tetraethylenepentamine)-cobalt(III) and photochemistry of oxygen and sulfur-bonded thiosulfato complexes

Summary The reaction of ()-(tetren)CoOH²⁺ with S₂O ₃ ^2- in the 7.25–8.28 pH range at 20–40 °C yielded S- (yellow) and O- (purple) bonded thiosulfato(tetren)cobalt(III) complexes, the former in larger quantities. The rate determining step is preceded by diffusion-controlled ion-pair [(tetren)CoOH²⁺,S₂O ₃ ^2- ] formation. Replacement of coordinated OH^- by S₂O ₃ ^2- is interpreted in terms of an internal conjugate base mechanism: (tetren)CoOH²⁺ (tetren-H)CoOH ₂ ²⁺ , the reactive amido conjugate base being generated by intramolecular proton transfer from the coordinated NH site.In acid medium the S-bonded (tetren)Co(S₂O₃)⁺ is highly stable to redox decomposition, in contrast to its pentaammine analogue. The complex however, undergoes base hydrolysis yielding the corresponding hydroxo complex. The rate and activation parameters for the base hydrolysis have been reported. Photolysis of O- and S-bonded isomers of [(tetren)CoS₂O₃]⁺ in acidic medium at 254 and 313 nm, respectively, yielded aquation products accompanied by some decomposition of S₂O ₃ ^2- .     

Synthesis of (NHC)Rh(cod)Cl and (NHC)RhCl(CO)2 complexes – Translation of the Rh- into the Ir-scale for the electronic properties of NHC ligands

Twenty-three different Rh complexes of the (NHC)RhCl(cod) and (NHC)RhCl(CO)₂ type were synthesized from [RhCl(cod)]₂. The electron donating nature of the NHC ligands was changed in a systematic manner. The redox potentials of the various (NHC)RhCl(cod) and the ν(CO) of the various (NHC)RhCl(CO)₂ were determined. A correlation of the Rh redox potentials and the Rh ν(CO), respectively, with the related data from analogous (NHC)IrCl(cod) and (NHC)IrCl(CO)₂ complexes established two linear relationships. The linear regression (R² = 0.993) of the Rh and the Ir redox potentials results in an equation for the redox potential transformation: E_1/2(Ir) = 1.016 · E_1/2(Rh) ? 0.076 V. The linear regression (R² = 0.97) of the Rh and Ir ν_av(CO) results in an equation for the ν_av(CO) transformation: ν_av(CO)Ir = 0.8695 · ν_av(CO)Rh + 250.7 cm^?1. In this manner the Rh and the Ir-scale for the determination of the electron donating properties of NHC ligands are unified.     

Dependence of the chemical properties of macrocyclic [Ni(II)(2)L(μ-O(2)CR)](+) complexes on the basicity of the carboxylato coligands (L(2-) = macrocyclic N(6)S(2) ligand)

The dependence of the properties of mixed ligand [Ni(II)(2)L(μ-O(2)CR)](+) complexes (where L(2-) represents a 24-membered macrocyclic hexaamine-dithiophenolato ligand) on the basicity of the carboxylato coligands has been examined. For this purpose 19 different [Ni(II)(2)L(μ-O(2)CR)](+) complexes (2-20) incorporating carboxylates with pK(b) values in the range 9 to 14 have been prepared by the reaction of [Ni(II)(2)L(μ-Cl)](+) (1) and the respective sodium or triethylammonium carboxylates. The resulting carboxylato complexes, isolated as ClO(4)(-) or BPh(4)(-) salts, have been fully characterized by elemental analyses, IR, UV/vis spectroscopy, and X-ray crystallography. The possibility of accessing the [Ni(II)(2)L(μ-O(2)CR)](+) complexes by carboxylate exchange reactions has also been examined. The main findings are as follows: (i) Substitution reactions between 1 and NaO(2)CR are not affected by the basicity or the steric hindrance of the carboxylate. (ii) Complexes 2-20 form an isostructural series of bisoctahedral [Ni(II)(2)L(μ-O(2)CR)](+) compounds with a N(3)Ni(μ-SR)(2)(μ-O(2)CR)NiN(3) core. (iii) They are readily identified by their ν(as)(CO) and ν(s)(CO) stretching vibration bands in the ranges 1684-1576 cm(-1) and 1428-1348 cm(-1), respectively. (iv) The spin-allowed (3)A(2g) → (3)T(2g) (ν(1)) transition of the NiOS(2)N(3) chromophore is steadily red-shifted by about 7.5 nm per pK(b) unit with increasing pK(b) of the carboxylate ion. (v) The less basic the carboxylate ion, the more stable the complex. The stability difference across the series, estimated from the difference of the individual ligand field stabilization energies (LFSE), amounts to about 4.2 kJ/mol [Δ(LFSE)(2,18)]. (vi) The "second-sphere stabilization" of the nickel complexes is not reflected in the electronic absorption spectra, as these forces are aligned perpendicularly to the Ni-O bonds. (vii) Coordination of a basic carboxylate donor to the [Ni(II)(2)L](2+) fragment weakens its Ni-N and Ni-S bonds. This bond weakening is reflected in small but significant bond length changes. (viii) The [Ni(II)(2)L(μ-O(2)CR)](+) complexes are relatively inert to carboxylate exchange reactions, except for the formato complex [Ni(II)(2)L(μ-O(2)CH)](+) (8), which reacts with both more and less basic carboxylato ligands.     

“2009中国科学仪器发展年会(ACCSI 2009)”在京隆重召开

2009年4月9日,以“迎接挑战,把握机遇,自主创新”为主题,“2009中国科学仪器发展年会（AccsI 2009）”在北京隆重召开。本届年会由中国仪器仪表行业协会、中国仪器仪表学会分析仪器分会、仪器信息网（www.instrument.com.cn）联合主办,中国分析测试协会协办,多个相关学会予以了大力支持。     

Synthesis of the Natural Products Resveratrol (Ⅰ) and Isorhapotogenin (Ⅱ)

ResveratrolIandisorhapotigeninIIaretwonaturalproductswithmanybiologicalactivities',andtheirtotalsynthesis'havebeenreported.LinMaoetal3flrstisolatedthemfromG.parvofOlium,atraditionalChineseherbusedtotreatrheumatoidarthritis,ulcerbleedingandbronchitis.Inanattempttopreparecnoughsamplesfortlirtherpharmacologicalevaluation,severalsynthesisstrategieshavebeenexplored'.WchavcdevelopedtwosyntheticapproachesofIandIIinSchemelandScheme2,respectivcly.Startingfrom3,5-dihydroxybenzoicacid,thecompound2wa…     

Electrochemical and Theoretical Investigations of the Role of the Appended Base on the Reduction of Protons by [Fe(2) (CO)(4) (κ(2) -PNP(R) )(μ-S(CH(2) )(3) S] (PNP(R) ={Ph(2) PCH(2) }(2) NR, R=Me, Ph)

The behavior of [Fe(2) (CO)(4) (κ(2) -PNP(R) )(μ-pdt)] (PNP(R) =(Ph(2) PCH(2) )(2) NR, R=Me (1), Ph (2); pdt=S(CH(2) )(3) S) in the presence of acids is investigated experimentally and theoretically (using density functional theory) in order to determine the mechanisms of the proton reduction steps supported by these complexes, and to assess the role of the PNP(R) appended base in these processes for different redox states of the metal centers. The nature of the R substituent of the nitrogen base does not substantially affect the course of the protonation of the neutral complex by CF(3) SO(3) H or CH(3) SO(3) H; the cation with a bridging hydride ligand, 1?μH(+) (R=Me) or 2?μH(+) (R=Ph) is obtained rapidly. Only 1?μH(+) can be protonated at the nitrogen atom of the PNP chelate by HBF(4) ?Et(2) O or CF(3) SO(3) H, which results in a positive shift of the proton reduction by approximately 0.15?V. The theoretical study demonstrates that in this process, dihydrogen can be released from a η(2) -H(2) species in the Fe(I) Fe(II) state. When R=Ph, the bridging hydride cation 2?μH(+) cannot be protonated at the amine function by HBF(4) ?Et(2) O or CF(3) SO(3) H, and protonation at the N atom of the one-electron reduced analogue is also less favored than that of a S atom of the partially de-coordinated dithiolate bridge. In this situation, proton reduction occurs at the potential of the bridging hydride cation, 2?μH(+) . The rate constants of the overall proton reduction processes are small for both complexes 1 and 2 (k(obs) ≈4-7?s(-1) ) because of the slow intramolecular proton migration and H(2) release steps identified by the theoretical study.     

Structural effects of the lone pair on lead(II), and parallels with the coordination geometry of mercury(II). Does the lone pair on lead(II) form H-bonds? Structures of the lead(II) and mercury(II) complexes of the pendant-donor macrocycle DOTAM (1,4,7,10-tetrakis(carbamoylmethyl)-1,4,7,10-tetraazacyclododecane)

The synthesis and structures of [Pb(DOTAM)](ClO4)2.4.5H2O (1) and [Hg(DOTAM)](ClO4)2.0.5CH3OH.1.5H2O (2) are reported, where DOTAM is 1,4,7,10-tetrakis(carbamoylmethyl)-1,4,7,10-tetraazacyclododecane. Compound 1 is triclinic, space group P, a = 12.767(3) A, b = 13.528(2) A, c = 18.385(3) A, alpha = 101.45(2) degrees, beta = 93.32(2) degrees, gamma = 90.53(2) degrees, Z = 4, R = 0.0500. Compound 2 is monoclinic, space group Cc, a = 12.767(3) A, b = 13.528(2) A, c = 18.385(3) A, beta = 101.91(2) degrees, Z = 4, R = 0.0381. The Pb(II) ion in 1 has an average Pb-N = 2.63 A to four N-donors from the macrocyclic ring, and four O-donors (average Pb-O = 2.77 A) from the amide pendant donors of the macrocycle, with a water molecule placed with Pb-O = 3.52 A above the proposed site of the lone pair (Lp) on Pb. The Hg(II) in 2 appears to be only six-coordinate, with four Hg-N bond lengths averaging 2.44 A, and two Hg-O from pendant amide donors at 2.41 A. The other two amide donors appear to be noncoordinating, with Hg-O distances of 2.74 and 2.82 A. A water situated 3.52 A above the proposed site of the lone pair on Pb(II) in 1 is oriented in such a way that it might be thought to be forming a Pb-Lp.H-O-H hydrogen bond. It is concluded that that this is not an H-bond, but that the presence of the lone pair allows a closer approach of the hydrogens to Pb than would be true otherwise. The structural analogy in the VSEPR sense between Pb(II), which has the 5d(10)6s(2) outer electron structure, and the Hg(II) ion, which has the 5d10 structure, is examined. The tendency of Hg(II) toward linear coordination, with two short Hg-L bonds (L = ligand) at 180 degrees to each other, and other donor groups at roughly 90 degrees to this and at much longer bond distances, is paralleled by Pb(II). One of the short Hg-L bonds is replaced in the Pb(II) structures by the lone pair (Lp), which is opposite the short Pb-L bond, or in some cases 2-4 shorter Pb-L bonds.     

Co(η(5) -P(5) ){η(2) -P(2) H(mes)}](2-) : A Phospha-Organometallic Complex Obtained by the Transition-Metal-Mediated Activation of the Heptaphosphide Trianion

A carbon copy: The chemical activation of the heptaphosphide trianion with [Co(PEt(2) Ph)(2) (mes)(2) ] (see picture; 1) yields the novel phospha-organometallic complex [Co(η(5) -P(5) ){η(2) -P(2) H(mes)}](2-) (2). The reaction product maintains the nuclearity of the parent cluster, but extensive cage fragmentation takes place to yield a diamagnetic "inorganometallic" cobalt complex.     

Report of the TrainMiC® Convention, held in Celje, Slovenia (10–14 January 2009)

The main aim of the TrainMiC^® Convention was to gather TrainMiC^® authorized trainers from all 19 countries involved in this programme. About 90% of all authorized TrainMiC^® trainers assembled at this Convention, which shows the interest in and usefulness of the TrainMiC^® system. The role and position of the authorized trainers was formally recognized by the introduction of a User License Agreement (based on a European Commission Decision, concerning the granting of a copyright license for TrainMiC^® trainers, 17 December 2008) which was signed by the attendants. Participants received an update on the training material and could give their input and suggestions for improvement, which will then be discussed and reviewed by the Editorial Board. It is this which makes TrainMiC^® a truly devolved and living system which can adapt itself. Participants also gave their input on how to further develop TrainMiC^® from a system point of view. Topics included better focus on priority sectors, improved course interactivity, further improvement of pedagogical skills of authorized trainers, better marketing and identifying multiple sources of funding.     

In situ study of the breakout crystallization in the poly(butadiene)-block-poly(ε-caprolactone) thin film

Despite its wide occurrence in soft confined block co-polymers, breakout crystallization remains poorly understood and is difficult to control. In this work, thin films of cylinder-forming poly(butadiene)-block-poly(ε-caprolactone) (PB-b-PCL) diblock co-polymers, with PCL being the minority block, have been chosen as the study subject. We demonstrate a new route to study the breakout crystallization by obtaining the microphase separation structure within terraced lamellae first and then in situ tracking down the lamellar coalescence, resulting from the development of the crystal growth front. We find that the crystal growth front has sucked materials from the surrounding amorphous lamellae, which lead to the decrease of the lamellar zones and coalescence of the microphase separation structure. Dividing the breakout crystallization into parallel breakout and vertical breakout, we illustrate that it is the crystallization-driven molecular diffusion that make the molecules overcome the topography constraint and grow into large-scale spherulite. Moreover, the results show that the polymer microphase separation structure has a significant influence on the crystal nucleation and greatly retarded the crystal growth rate. With a well-designed microphase separation structure within terraces and an easily tunable atomic force microscopy in situ imaging technique, an intensive study of the breakout crystallization and concomitant microdomain coalescence has been offered.     

Effects of Y (Ⅲ) Ions on the Fluorescence Properties of Ce(Ⅲ) Ion and the Organic Ligands in the Complex

The enhancement effects of Y ( Ⅲ) ions on the fluorescence of Ce ( Ⅲ) in Ce ( Ⅲ)-Y ( Ⅲ)-PMMA (polymethylmethacrylate ) or Ce ( Ⅲ)-Y ( Ⅲ)-PVC (polyvinyl chloride ) complex systems were observed. The influence of Y ( Ⅲ) ions on the emission spectra of PMMA ligands in PMMA-Y ( Ⅲ) and the fluorescent enhance- ment of Y( Ⅲ) on Ce( Ⅲ) emission in PMMA-Ce-Y by Y( Ⅲ) ion were studied. It was also of interest to note that when Y ( Ⅲ) ions were added into PMMA and into bpy(bipyridine ), respectively, the emission spectrum of PMMA ligands was split into fine structure bands by Y ( Ⅲ), and the fluorescence intensities of bpy ligands in bpy-Y ( Ⅲ) complexes were considerably increased.     

Beryllium(II) complexes of the Kläui tripodal ligand cyclopentadienyltris(diethylphosphito-p)cobaltate(-)

The interactions of the beryllium(II) ion with the cyclopentadienyltris(diethylphosphito-P)cobaltate monoanion, L(-), have been investigated, in aqueous solution, by synthetic methods, potentiometry, ESMS, and (1)H, (31)P, and (9)Be NMR spectroscopy. L(-) has been found able to displace either two or three water molecules in the beryllium(II) coordination sphere, to form mononuclear, dinuclear, and trinuclear derivatives, in which the metal ion is pseudotetrahedrally coordinated. The species [BeL(H(2)O)](+) and [Be(2)L(2)(mu-OH)](+) have been identified in solution while complexes of formula BeL(2) and [Be(3)L(4)](ClO(4))(2) have been isolated as solid materials. The species [BeL(OPPh(2))](+), closely related to [BeL(H(2)O)](+), has been characterized in acetone solution and isolated as tetraphenylborate salt. The structure of the unusual trimeric complex [Be(3)L(4)](2+) has been elucidated by an unprecedented 2D (9)Be-(31)P NMR correlation spectrum showing the presence of a single central beryllium nucleus and two equivalent terminal beryllium nuclei. The three beryllium centers are held together by four cobaltate ligands, which display two different bonding modes: two ligands are terminally linked with all the three oxygen donors to one terminal beryllium, and the other two bridge two metal centers, sharing the oxygen donors between central and terminal beryllium atoms.     

Accessibility and Selective Stabilization of the Principal Spin States of Iron by Pyridyl versus Phenolic Ketimines: Modulation of the (6)A(1) ↔ (2)T(2) Ground-State Transformation of the [FeN(4)O(2)](+) Chromophore

Several potentially tridentate pyridyl and phenolic Schiff bases (apRen and HhapRen, respectively) were derived from the condensation reactions of 2-acetylpyridine (ap) and 2'-hydroxyacetophenone (Hhap), respectively, with N-R-ethylenediamine (RNHCH(2)CH(2)NH(2), Ren; R = H, Me or Et) and complexed in situ with iron(II) or iron(III), as dictated by the nature of the ligand donor set, to generate the six-coordinate iron compounds [Fe(II)(apRen)(2)]X(2) (R = H, Me; X(-) = ClO(4)(-), BPh(4)(-), PF(6)(-)) and [Fe(III)(hapRen)(2)]X (R = Me, Et; X(-) = ClO(4)(-), BPh(4)(-)). Single-crystal X-ray analyses of [Fe(II)(apRen)(2)](ClO(4))(2) (R = H, Me) revealed a pseudo-octahedral geometry about the ferrous ion with the Fe(II)-N bond distances (1.896-2.041 ?) pointing to the (1)A(1) (d(π)(6)) ground state; the existence of this spin state was corroborated by magnetic susceptibility measurements and M?ssbauer spectroscopy. In contrast, the X-ray structure of the phenolate complex [Fe(III)(hapMen)(2)]ClO(4), determined at 100 K, demonstrated stabilization of the ferric state; the compression of the coordinate bonds at the metal center is in accord with the (2)T(2) (d(π)(5)) ground state. Magnetic susceptibility measurements along with EPR and M?ssbauer spectroscopic techniques have shown that the iron(III) complexes are spin-crossover (SCO) materials. The spin transition within the [Fe(III)N(4)O(2)](+) chromophore was modulated with alkyl substituents to afford two-step and one-step (6)A(1) ? (2)T(2) transformations in [Fe(III)(hapMen)(2)]ClO(4) and [Fe(III)(hapEen)(2)]ClO(4), respectively. Previously, none of the X-salRen- and X-sal(2)trien-based ferric spin-crossover compounds exhibited a stepwise transition. The optical spectra of the LS iron(II) and SCO iron(III) complexes display intense d(π) → p(π)* and p(π) → d(π) CT visible absorptions, respectively, which account for the spectacular color differences. All the complexes are redox-active; as expected, the one-electron oxidative process in the divalent compounds occurs at higher redox potentials than does the reverse process in the trivalent compounds. The cyclic voltammograms of the latter compounds reveal irreversible electrochemical generation of the phenoxyl radical. Finally, the H(2)salen-type quadridentate ketimine H(2)hapen complexed with an equivalent amount of iron(III) to afford the μ-oxo-monobridged dinuclear complex [{Fe(III)(hapen)}(2)(μ-O)] exhibiting a distorted square-pyramidal geometry at the metal centers and considerable antiferromagnetic coupling of spins (J ≈ -99 cm(-1)).     

Cyclic structure of the β(γ)-hydroxy-(mercapto)alkylimines of aldoses

In solutions in DMSO-d₆, the products from the condensation of ethanolamine and 1,2- and 1,3-aminopropanols with aldoses are mixtures of the - and -pyranose forms, whereas the -mercaptoethylimines of aldoses have the 1,3-thiazolidine structure. Glucose -mercaptoethylimine is characterized by ring-chain tautomerism involving the -pyranose and diastereomeric 1,3-thiazolidine tautomers.Military-Medical Academy, St. Petersburg, Russia. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1068–1071, August, 1998.     

A μ(1,1)- or μ(1,3)-carboxylate bridge makes the difference in the magnetic properties of dinuclear Mn(II) compounds

Six new dinuclear Mn(II) compounds with carboxylate bridges have been synthesized and characterized by X-ray diffraction: [{Mn(phen)(2)}(2)(μ-RC(6)H(4)COO)(2)](ClO(4))(2) with R = 2-Cl (1), 2-CH(3) (2), 3-Cl (3), 3-CH(3) (4), 4-Cl (5) and 4-CH(3) (6). Compounds 1 and 2 show two μ(1,3)-carboxylate bridges in a syn-anti mode while compounds 3-6 present a very uncommon coordination mode of the carboxylate ligand: the μ(1,1)-bridge. The magnetic properties of these compounds are very sensitive to the bridging mode of the carboxylate ligands. While compounds 1 and 2 (μ(1,3)-bridge) display antiferromagnetic interactions, with J values of -1.41 and -1.66 cm(-1), respectively, compounds 3-6 (μ(1,1)-bridge) show ferromagnetic interactions, with J values of 1.01, 0.98, 1.04 and 1.06 cm(-1), respectively. It is worth noting that compounds 3-6 are the first of their class to be magnetically characterized. The EPR spectra at 4 K for compounds with antiferromagnetic coupling (1 and 2) are more complex than those for compounds with a ferromagnetic interaction (3-6). Quite good simulations can be obtained with the ZFS parameters of the Mn(II) ion D(Mn) ~ 0.095 cm(-1) and E(Mn) ~ 0.025 cm(-1) for compounds 1 and 2 and D(Mn) ~ 0.060 cm(-1) and E(Mn) ~ 0.004 cm(-1) for compounds 3-6.