Refine
Year of publication
Document Type
- Article (2231)
- Doctoral Thesis (348)
- Postprint (226)
- Review (30)
- Other (27)
- Conference Proceeding (15)
- Habilitation Thesis (14)
- Monograph/Edited Volume (13)
- Preprint (7)
- Part of a Book (1)
Language
- English (2913) (remove)
Keywords
- nanoparticles (28)
- self-assembly (22)
- DNA origami (20)
- Nanopartikel (19)
- biomaterials (19)
- block copolymers (15)
- Conformational analysis (14)
- SERS (14)
- ionic liquids (14)
- fluorescence (13)
Institute
- Institut für Chemie (2913) (remove)
Driven mostly by the search for chemical syntheses under biocompatible conditions, so called "click" chemistry rapidly became a growing field of research. The resulting simple one-pot reactions are so far only scarcely accompanied by an adequate optimization via comparably straightforward and robust analysis techniques possessing short set-up times. Here, we report on a fast and reliable calibration-free online NMR monitoring approach for technical mixtures. It combines a versatile fluidic system, continuous-flow measurement of H-1 spectra with a time interval of 20 s per spectrum, and a robust, fully automated algorithm to interpret the obtained data. As a proof-of-concept, the thiol-ene coupling between N-boc cysteine methyl ester and ally] alcohol was conducted in a variety of non-deuterated solvents while its time-resolved behaviour was characterized with step tracer experiments. Overlapping signals in online spectra during thiol-ene coupling could be deconvoluted with a spectral model using indirect hard modeling and were subsequently converted to either molar ratios (using a calibration free approach) or absolute concentrations (using 1-point calibration). For various solvents the kinetic constant k for pseudo-first order reaction was estimated to be 3.9 h(-1) at 25 degrees C. The obtained results were compared with direct integration of non-overlapping signals and showed good agreement with the implemented mass balance. (C) 2017 Elsevier Inc. All rights reserved.