NMR Quantification of Halogen-Bonding Ability To Evaluate Catalyst Activity
摘要:
Quantification of halogen-bonding abilities is described for a series of benzimidazolium-, imidazolium- and bis(imidazolium) halogen-bond donors (XBDs) using P-31 NMR spectroscopy. The measured Delta delta(P-31) values correlate with calculated activation free energy Delta G(double dagger) and catalytic activity for a Friedel-Crafts indole addition. This rapid method also serves as a sensitive indicator for Bronsted acid impurities.
NMR Quantification of Halogen-Bonding Ability To Evaluate Catalyst Activity
摘要:
Quantification of halogen-bonding abilities is described for a series of benzimidazolium-, imidazolium- and bis(imidazolium) halogen-bond donors (XBDs) using P-31 NMR spectroscopy. The measured Delta delta(P-31) values correlate with calculated activation free energy Delta G(double dagger) and catalytic activity for a Friedel-Crafts indole addition. This rapid method also serves as a sensitive indicator for Bronsted acid impurities.
Activation of Michael Acceptors by Halogen-Bond Donors
作者:Martin Breugst、Daniel von der Heiden、Eric Detmar、Robert Kuchta
DOI:10.1055/s-0036-1591841
日期:2018.6
catalysis, experimental investigations show that various halogen-bond donors can also be employed to accelerate the Michael addition between trans -crotonophenone and indole. Solvent as well as counteranion effects have been analyzed, and kinetic and computational investigations provide additional insights into the mode of activation.
Activation of a carbonyl compound by halogen bonding
作者:Stefan H. Jungbauer、Sebastian M. Walter、Severin Schindler、Laxmidhar Rout、Florian Kniep、Stefan M. Huber
DOI:10.1039/c4cc03124e
日期:——
are capable of activating a neutral organic substrate. By various comparison experiments, the action of traces of acid or of other structural features of the halogen-bond donor not related to halogenbonding are excluded with high certainty.