pH-Responsive chromogenic-sensing molecule based on bis(indolyl)methene for the highly selective recognition of aspartate and glutamate

• Litao Wang,
• Xiaoming He,
• Yong Guo,
• Jian Xu and
• Shijun Shao

Beilstein J. Org. Chem. 2011, 7, 218–221, doi:10.3762/bjoc.7.29

• receptor and guest. However, the basic H-bond acceptor moiety of 1 is very sensitive to changes of pH. Herein, we report a pH-responsive chromogenic-sensing molecule 1 that shows high selectivity for Asp and Glu in a mixed acetonitrile/water medium. Results and Discussion The synthesis of 1 was according

• pH-responsive colorimetric sensor for amino acids, the receptor shows high selectivity and sensitivity for Asp and Glu. Structure of sensor 1. Changes in UV–vis spectra of 1 (5.0 × 10−5 M) after addition of: (a) 0–0.10 mL H2O; (b) various ratios of the CH3CN/H2O (fixed volume is 4 mL). pH-dependent

Novel multi-responsive P2VP-block-PNIPAAm block copolymers via nitroxide-mediated radical polymerization

• Cathrin Corten,
• Katja Kretschmer and
• Dirk Kuckling

Beilstein J. Org. Chem. 2010, 6, 756–765, doi:10.3762/bjoc.6.89

• -vinylpyridine (2VP), is one point of interest because at pH values lower than 5 it is possible to protonate the 2VP units and hence P2VP can be used as a pH-responsive component. Several techniques such as NMRP, ATRP and RAFT led to well-defined homo and block copolymers of different architectures whose

• ) chloride, well-defined PNIPAAm could be synthesized at room temperature [27]. Several graft copolymers are described in previous reports such as Chitosan-graft-PNIPAAm [28] and PNIPAAm-graft-P2VP polymers [29]. Both polymers show a temperature- and pH-responsive phase behavior in aqueous solutions. While