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691.
The ring-opening oligomerization reaction of propylene carbonate in the presence of the tert-butylphenol/KHCO3 initiating system was studied by means of Matrix-Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry (MALDI-TOF MS) and Electrospray Ionization Time of Flight Mass Spectrometry (ESI-TOF MS). According to the MS spectra obtained, different series of peaks were identified. The MS spectra clearly showed that besides the chain-extension reaction yielding oligomers with all propylene oxide units, the formation of oligomers containing carbonate linkages in the chain, and condensation reaction between the latter two also took place. The structure of the oligomers carrying carbonate linkages was determined by the post-source decay (PSD) MALDI-TOF MS/MS method. Based on the MS results, a mechanism for the oligomerization reaction is proposed. 相似文献
692.
Elisabeth Holder Veronica Marin Michael A. R. Meier Ulrich S. Schubert 《Macromolecular rapid communications》2004,25(16):1491-1496
Summary : A monoterpyridine‐poly(ethylene glycol) (mono‐tpy‐PEG) and a novel monoterpyridine‐PEG‐functionalized iridium(III ) complex were successfully synthesized and fully characterized by means of NMR, IR, and UV‐vis spectroscopy, as well as gel permeation chromatography and matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry. The functionalized monoterpyridine iridium(III ) complex was synthesized by a bridge‐splitting reaction of a dimeric iridium(III ) precursor complex using a chelating terpyridine ligand with a poly(ethylene glycol) tail. With this approach, a new class of light‐emitting polymeric materials revealing interesting optical properties was made avaialable.
693.
Hiroshi Katayama Hiroaki Kitaguchi Masami Kamigaito Mitsuo Sawamoto 《Journal of polymer science. Part A, Polymer chemistry》2000,38(22):4023-4031
Matrix‐assisted laser desorption ionization time of flight mass spectrometry (MALDI‐TOF‐MS) was utilized for the analysis of polymers obtained by the living cationic polymerization of isobutyl vinyl ether (IBVE) with the HCl‐VE adduct/SnCl4/n‐Bu4NCl initiating system in CH2Cl2 at −78 °C. Under optimized analysis conditions, well‐resolved spectra were obtained for samples with number‐average molecular weights of ≤104 with the use of 1,8‐dihydroxy‐9(10H)‐anthracenone (dithranol) as a matrix and sodium trifluoroacetate as an added salt. The MS spectra showed only one series of peaks separated exactly by the mass of the IBVE. The observed mass of each peak was in good agreement with the theoretical one, which possesses one initiator fragment at the α end and one methoxy group originated from quenching with methanol at the ω end. Thus, detailed end group analysis is possible for poly(VE). © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 4023–4031, 2000 相似文献
694.
The present study attempted to apply the capillary electrophoresis technique for the fractionation and separation of S. Staphylococcus hominis and Escherichia coli bacteria isolated from urine samples and the detection of migrated fraction with spectrometric method. This involved the selection of suitable conditions for separation as well as the identification of pathogens. The result of the research was the separation of Gram-negative and Gram-positive bacteria, as well as their subsequent identification by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry using two different approaches (culture of fractions on an agar plate and direct analysis of the collected fractions). The preliminary results provide a solid basis for further research on the use of electromigration techniques with LDI detection to identify pathogens such as bacteria and viruses in biological samples. 相似文献
695.
Niklas Gangloff Corinna Fetsch Robert Luxenhofer 《Macromolecular rapid communications》2013,34(12):997-1001
The nucleophilic living ring‐opening polymerization of N‐substituted glycine N‐carboxyanhydrides using solid‐phase synthesis resins is reported. By variation of experimental parameters, products with near Poisson distributions are obtained. As opposed to reversible deactivation radical polymerization, the living polymerization is demonstrated to be viable to high monomer conversion and through multiple monomer addition steps. Successful preparation of a multiblock copolypeptoid is proof for a highly living and robust character of the solid‐phase peptoid polymerization.
696.
Michael A. R. Meier Bas G. G. Lohmeijer Ulrich S. Schubert 《Macromolecular rapid communications》2003,24(14):852-857
The characterization of metal‐containing supramolecular polymers by gel permeation chromatography (GPC) or matrix‐assisted laser desorption ionisation time‐of‐flight mass spectrometry (MALDI‐TOF MS) is complicated because of the interaction of the charged materials with the GPC column material in the first case and fragmentation due to the applied laser energy in the latter case. In this contribution we report recent advances made for the characterization of supramolecular polymers based on terpyridine metal complexes utilizing GPC and MALDI‐TOF MS. In particular for GPC analysis, the choice of solvent and additive was found to be crucial for a successful characterization. Furthermore, MALDI‐TOF MS spectra of these compounds are not straightforward to interpret. Both aspects are discussed in detail with the result of a better understanding and improved analysis possibilities of the mentioned supramolecular polymers.
697.
Christian Slugovc Silvia Riegler Gertraud Hayn Robert Saf Franz Stelzer 《Macromolecular rapid communications》2003,24(7):435-439
The “3rd generation Grubbs” initiator (H2IMes)(3‐bromopyridine)2(Cl)2RuCHPh ( 1 ) accomplishes the synthesis of ABC triblock copolymers via living ring‐opening metathesis polymerisation (ROMP) of norbornene derivatives. Complete initiation and an outstanding tolerance of functional groups are provided, which is proven by a combined study by means of matrix‐assisted laser desorption/ionisation mass spectrometry, gel permeation chromatography and NMR spectroscopy on an ABC triblock cooligomer.
698.
Emilio Scamporrino Sebastiano Bazzano Daniele Vitalini Placido Mineo 《Macromolecular rapid communications》2003,24(3):236-241
The preparation of a bisphenol‐A carbonate copolymer, containing Cu‐diimine units with nonlinear optical (NLO) properties, and its MALDI‐TOF mass spectrometric characterization are reported. Contrary to the usual synthetic method, NLO groups were inserted directly into a commercial polycarbonate by prolonged heating at 250 °C. This innovative procedure allows to obtain a Cu/diimine‐containing polymer of high molecular weight.