Cooperative NH⋯O and CH⋯O interactions for sulfate encapsulation in a thiophene-based macrocycle
✍ Scribed by Musabbir A. Saeed; Douglas R. Powell; Frank R. Fronczek; Md. Alamgir Hossain
- Book ID
- 104097959
- Publisher
- Elsevier Science
- Year
- 2010
- Tongue
- French
- Weight
- 737 KB
- Volume
- 51
- Category
- Article
- ISSN
- 0040-4039
No coin nor oath required. For personal study only.
✦ Synopsis
A thiophene-based macrocycle containing four secondary and two tertiary amines has been synthesized and its binding affinity has been investigated toward sulfate anion in solution and solid states. Structural analysis of the sulfate salt suggests that the ligand in its hexaprotonated form is capable of encapsulating one sulfate within the cavity through cooperative NHÁ Á ÁO and CHÁ Á ÁO interactions. As investigated by 1 H NMR titrations, the ligand forms a 1:1 complex with sulfate in water at pH 2.1, showing a binding constant (K) of 3200 M À1 . The formation of the complex has been further confirmed by ESI-MS, indicating that the complex can exist in solution with considerable stability.