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91.
Kinetico‐Mechanistic Insights on the Assembling Dynamics of Allyl‐Cornered Metallacycles: The PtNpy Bond is the Keystone 下载免费PDF全文
Dr. Inmaculada Angurell Dr. Montserrat Ferrer Dr. Albert Gutiérrez Prof. Manuel Martínez Dr. Mercè Rocamora Dr. Laura Rodríguez Prof. Oriol Rossell Dipl.‐Chem. Yvonne Lorenz Dr. Marianne Engeser 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(44):14473-14487
The square‐like homo‐ and heterometallamacrocycles [{Pd(η3‐2‐Me‐C3H4)( L n )2}2{M(dppp)}2](CF3SO3)6 (dppp=1,3‐bis(diphenylphosphino)propane) and [{Pd(η3‐2‐Me‐C3H4)( L1 )2}2{M(PPh3)2}2](CF3SO3)6 [py=pyridine, M=Pd, Pt, L n =4‐PPh2py ( L1 ), 4‐C6F4PPh2py ( L2 )] containing allyl corners were synthesised by antisymbiotic self‐assembly of the different palladium and platinum metallic corners and the ambidentate N,P ligands. All the synthesised assemblies displayed a complex dynamic behaviour in solution, the rate of which is found to be dependent on the electronic and/or steric nature of the different building blocks. A kinetico‐mechanistic study by NMR line shape analysis of the dynamics of some of these assemblies was undertaken in order to determine the corresponding thermal activation parameters. Both an enhanced thermodynamic stability and slower dynamics were observed for platinum‐pyridine‐containing species when compared with their palladium analogues. Time‐dependent NMR spectroscopy in combination with ESI mass spectrometry was used to study the exchange between the assemblies and their building blocks, as well as that occurring between different metallamacrocycles. Preliminary studies were carried out on the activity of some of the metallamacrocyclic compounds as catalytic precursors in the allylic substitution reaction, and the results compared with that of the monometallic allylic corner [Pd(η3‐2‐Me‐C3H4)( L1 )2]+. 相似文献
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Reaction of N-tert-butyloxycarbonylasparagine (Boc-Asn) with 2 equiv of benzyl bromide in presence of cesium carbonate led to N-benzyl-3-Boc-amino-pyrrolidin-2,5-dione 1a (N-benzyl-3-Boc-aminosuccinimide). Borane dimethylsulfide reduced 3-Boc-aminopyrrolidine-2,5-dione 1a into 3-Boc-aminopyrrolidin-2-one 2a. The same procedure could also be used to prepare derivatives 1 and 2 substituted on the aromatic ring. 相似文献
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Non-enzymic glycation of human serum albumin (HSA) induces a change in its charge heterogeneity that may account for its particular renal clearance in patients with early diabetic nephropathy. A new high-performance liquid chromatographic analysis for the study of HSA heterogeneity is described based on a high content of formic acid in the mobile phase combined with a concave gradient of isopropanol. Under these conditions, native HSA was separated into three individual components (I, II and III). When glycated HSA was analysed, it was found that although the present method is not suitable for the separation of glycated from non-glycated HSA, it shows the effect of glycation in producing changes in HSA heterogeneity that are different from those reported on surface change. This finding suggests an additional factor (probably conformational changes) that is contributing to the heterogeneity of glycated HSA. 相似文献
95.
Montserrat Ferrer Anna Juli Roser Reina Oriol Rossell Miquel Seco Dominique de Montauzon 《Journal of organometallic chemistry》1998,560(1-2)
Treatment of [(ClAu)2(diphosphine)] {diphosphine=bis(diphenylphosphino)methane (dppm), bis(diphenylphosphino)isopropane (dppip), 1,2-bis(diphenylphosphino)ethane (dppe), 1,3-bis(diphenylphosphino)propane (dppp)} with two equivalents of the anion [Fe2(μ-CO)(CO)6(μ-PPh2)]− in the presence of TlBF4 gives the new heterometallic diclusters [{Fe2(μ-CO)(CO)6(μ-PPh2)Au}2(diphosphine)] that have been isolated and characterized. Their 31P-NMR spectra show different patterns as a function of the diphosphine ligand. The electrochemical behavior of these compounds has been investigated and compared with that of the mono- [Fe2(μ-CO)(CO)6(μ-PPh2)(μ-AuPPh3)] and tricluster [{Fe2(μ-CO)(CO)6(μ-PPh2)Au}3(triphos)] derivatives. 相似文献
96.
A Garrido Frenich J R Torres-Lapasió K De Braekeleer D L Massart J L Martínez Vidal M Martínez Galera 《Journal of chromatography. A》1999,855(2):487-499
Simple to use interactive self-modelling mixture analysis (SIMPLISMA), orthogonal projection (OPA) and Needle Search (NS) approaches have been applied to the determination of a number of compounds present in a complex multicomponent system. None of these three approaches succeeded completely when they were tested using the whole data matrix. When OPA and NS were applied to three simpler submatrices, obtained by dividing the total data matrix, and where a smaller number of compounds were present, better performance was achieved. 相似文献
97.
Sergio Escalera Oriol Pujol Josepa Mauri Petia Radeva 《Journal of Signal Processing Systems》2009,55(1-3):35-47
Intravascular ultrasound (IVUS) represents a powerful imaging technique to explore coronary vessels and to study their morphology and histologic properties. In this paper, we characterize different tissues based on radial frequency, texture-based, and combined features. To deal with the classification of multiple tissues, we require the use of robust multi-class learning techniques. In this sense, error-correcting output codes (ECOC) show to robustly combine binary classifiers to solve multi-class problems. In this context, we propose a strategy to model multi-class classification tasks using sub-classes information in the ECOC framework. The new strategy splits the classes into different sub-sets according to the applied base classifier. Complex IVUS data sets containing overlapping data are learnt by splitting the original set of classes into sub-classes, and embedding the binary problems in a problem-dependent ECOC design. The method automatically characterizes different tissues, showing performance improvements over the state-of-the-art ECOC techniques for different base classifiers. Furthermore, the combination of RF and texture-based features also shows improvements over the state-of-the-art approaches. 相似文献
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