0

Very Strong Binding for a Neutral Calix[4]pyrrole Receptor Displaying Positive Allosteric Binding

Troels Duedal, Kent A Nielsen, Gunnar Olsen, Charlotte B G Rasmussen, Jacob Kongsted, Eric Levillain, Tony Breton, Eigo Miyazaki, Kazuo Takimiya, Steffen Bähring, Jan O Jeppesen

J Org Chem. 2017 Feb 17;82(4):2123-2128.

PMID: 28121143

Abstract:

The dual-analyte responsive behavior of tetraTTF-calix[4]pyrrole receptor 1 has been shown to complex electron-deficient planar guests in a 2:1 fashion by adopting a so-called 1,3-alternate conformation. However, stronger 1:1 complexes have been demonstrated with tetraalkylammonium halide salts that defer receptor 1 to its cone conformation. Herein, we report the complexation of an electron-deficient planar guest, 1,4,5,8-naphthalenetetracarboxylic dianhydride (NTCDA, 2) that champions the complexation with 1, resulting in a high association constant Ka = 3 × 1010 M-2. The tetrathiafulvalene (TTF) subunits in the tetraTTF-calix[4]pyrrole receptor 1 present a near perfect shape and electronic complementarity to the NTCDA guest, which was confirmed by X-ray crystal structure analysis, DFT calculations, and electron density surface mapping. Moreover, the complexation of these species results in the formation of a charge transfer complex (22⊂1) as visualized by a readily apparent color change from yellow to brown.

Chemicals Related in the Paper:

Catalog Number Product Name Structure CAS Number Price
AP81301 1,4,5,8-Naphthalenetetracarboxylic dianhydride 1,4,5,8-Naphthalenetetracarboxylic dianhydride 81-30-1 Price
qrcode