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981.
982.
Jing-An Zhang Mei Pan Rui Yang Zhi-Gang She Wolfgang Kaim Zhi-Jin Fan Cheng-Yong Su 《Polyhedron》2010
The semirigid tridentate 8-(2-pyridinylmethylthio)quinoline ligand (Q1) is shown to form the structurally characterized transition metal complexes [Cu(Q1)Cl2] (1), [Co(Q1)(NO3)2] (2), [Cd(Q1)(NO3)2] (3), [Cd(Q1)I2] (4). [Cu(Q1)2](BF4)2·(H2O)2 (5), [Cu(Q1)2](ClO4)2·(CH3COCH3)2 (6), [Zn(Q1)2](ClO4)2(H2O)2 (7), [Cd2(Q1)2Br4] (8), [Ag2(Q1)2(ClO4)2] (9), and [Ag2(Q1)2(NO3)2] (10). Four types of structures have been observed: ML-type in complexes 1–4, in which the anions Cl−, NO3− or I− also participate in the coordination; ML2− type in complexes 5–7 without direct coordination of the anions BF4− or ClO4− and with more (Cu2+) or less (Zn2+) distorted bis-fac coordinated Q1; M2L2-type in complex 8, in which two Br− ions act as bridges between two metal ions; and M2(μ-L)2-type in complexes 9 and 10, in which the ligand bridges two anion binding and Ag–Ag bonded ions. Depending on electron configuration and size, different coordination patterns are observed with the bonds from the metal ions to Npyridyl longer or shorter than those to Nquinoline. Typically Q1 acts as a facially coordinating tridentate chelate ligand except for the compounds 9 and 10 with low-coordinate silver(I). Except for 6 and 8, the complexes exhibit distinct constraining effects against both G(+) and G(-) bacteria. Complexes 1, 3, 4, 5, 7 have considerable antifungal activities and complexes 1, 5, 7, and 10 show selective effects to restrain certain botanic bacteria. Electrochemical studies show quasi-reversible reduction behavior for the copper(II) complexes 1, 5 and 6. 相似文献
983.
Wolfgang W. Schoeller 《Theoretical chemistry accounts》2010,127(3):223-229
A density functional investigation into differently substituted silylenes with respect to the first step in the addition to white phosphorus is presented. The investigations include dispersion corrections in the density functional treatment. They become sizable for the transition state geometries for the silylenes as they become increasingly substituted by bulky groups. Hence, dispersion corrections are essential for a quantum chemical treatment of real molecules using density functional theory. The different singlet–triplet energy separations of differently substituted silylenes were also investigated and compared with calculated activation barriers for the first step in the addition reaction. 相似文献
984.
985.
986.
987.
Katharina K. Strelau Thomas Schüler Dr. Robert Möller Dr. Wolfgang Fritzsche Dr. habil. Jürgen Popp Prof. Dr. 《Chemphyschem》2010,11(2):394-398
Surface‐enhanced Raman spectroscopy (SERS) is an emerging technology in the field of analytics. Due to the high sensitivity in connection with specific Raman molecular fingerprint information SERS can be used in a variety of analytical, bioanalytical, and biosensing applications. However, for the SERS effect substrates with metal nanostructures are needed. The broad application of this technology is greatly hampered by the lack of reliable and reproducible substrates. Usually the activity of a given substrate has to be determined by time‐consuming experiments such as calibration or ultramicroscopic studies. To use SERS as a standard analytical tool, cheap and reproducible substrates are required, preferably with a characterization technique that does not interfere with the subsequent measurements. Herein we introduce an innovative approach to produce low‐cost and large‐scale reproducible substrates for SERS applications, which allows easy and economical production of micropatterned SERS active surfaces on a large scale. This approach is based on an enzyme‐induced growth of silver nanostructures. The special structural feature of the enzymatically deposited silver nanoparticles prevents the breakdown of SERS activity even at high particle densities (particle density >60 %) that lead to a conductive layer. In contrast to other approaches, this substrate exhibits a relationship between electrical conductivity and the resulting SERS activity of a given spot. This enables the prediction of the SERS activity of the nanostructure ensemble and therewith the controllable and reproducible production of SERS substrates of enzymatic silver nanoparticles on a large scale, utilizing a simple measurement of the electrical conductivity. Furthermore, through a correlation between the conductivity and the SERS activity of the substrates it is possible to quantify SERS measurements with these substrates. 相似文献
988.
Wolfgang Baether Stefan Zimmermann Frank Gunzer 《International Journal for Ion Mobility Spectrometry》2010,13(3-4):95-101
Ion mobility spectrometry (IMS) is a well-known method for detecting hazardous compounds in air. Most ion mobility spectrometers use a radioactive source to provide electrons with high energy (5–50 keV) to ionize analytes in a series of chemical reactions. Instead of a radioactive source, we use a non-radioactive electron gun which can be operated in pulsed mode. Thus a delay time between ionization and ion extraction can be introduced which offers the possibility to use the signal decay characteristic of substances as a further discrimination parameter. The influence of voltages supplied to the reaction region and to the electron gun on signal intensities and decay times will be investigated in order to obtain further insight into the dependence of this signal decay on different experimental parameters and correspondingly into the underlying mechanisms. 相似文献
989.
Jeon IeR Ababei R Lecren L Li YG Wernsdorfer W Roubeau O Mathonière C Clérac R 《Dalton transactions (Cambridge, England : 2003)》2010,39(20):4744-4746
In an attempt to develop novel coordination networks of SMMs, a Cu(II) picolinate complex has been used to coordinate S(T) = 9 tetranuclear Mn-based SMMs resulting in an intriguing 2D framework exhibiting a magnet-like behavior at low temperature. 相似文献
990.
Dmitrii A. Guschin John Castillo Nina Dimcheva Wolfgang Schuhmann 《Analytical and bioanalytical chemistry》2010,398(4):1661-1673
The design of polymers carrying suitable ligands for coordinating Os complexes in ligand exchange reactions against labile
chloro ligands is a strategy for the synthesis of redox polymers with bound Os centers which exhibit a wide variation in their
redox potential. This strategy is applied to polymers with an additional variation of the properties of the polymer backbone
with respect to pH-dependent solubility, monomer composition, hydrophilicity etc. A library of Os-complex-modified electrodeposition
polymers was synthesized and initially tested with respect to their electron-transfer ability in combination with enzymes
such as glucose oxidase, cellobiose dehydrogenase, and PQQ-dependent glucose dehydrogenase entrapped during the pH-induced
deposition process. The different polymer-bound Os complexes in a library containing 50 different redox polymers allowed the
statistical evaluation of the impact of an individual ligand to the overall redox potential of an Os complex. Using a simple
linear regression algorithm prediction of the redox potential of Os complexes becomes feasible. Thus, a redox polymer can
now be designed to optimally interact in electron-transfer reactions with a selected enzyme. 相似文献