Host-guest interaction of tryptophane with acid-functionalized calix[4]pyrrole: a fluorescence-based study

Abstract

Functionalized calix[4]pyrroles are at forefront of host-guest aided molecular sensors. They offer unique platform for flexible functionalization to develop receptors suitable for different applications. In this context, calix[4]pyrrole derivative (TACP) was functionalized with an acidic group to investigate its binding behavior with different amino acids. The acid functionalization facilitated host-guest interactions through hydrogen bonding and increase the solubility of ligand in 90% aqueous media. The results indicated that TACP exhibited significant fluorescence enhancement in the presence of tryptophan while no considerable changes were observed with other amino acids. The other complexation properties such as LOD and LOQ were determined to be 25 µM and 22 µM respectively with 1:1 stoichiometry. In addition, the proposed binding phenomena were further confirmed through computational docking studies and NMR complexation study. Overall, this work highlights the potential of acid functionalization in developing molecular sensors for amino acid detection using calix[4]pyrrole derivatives.

Communicated by Ramaswamy H. Sarma

Keywords:

• amino acid sensing
• calix[4]pyrrole
• docking
• fluorescence enhancement
• selectivity

Acknowledgment

The authors would like to acknowledge Chemistry Research Laboratory (CRL)-MUIS, Ganpat University for providing with infrastructure to carry out research work and Gujarat University for providing access to the spectrofluorometer and related resources .Authors are thankful to Dr. Alan Liska for providing the access to the computing and storage facilities owned by parties and projects corresponding to the National Grid Infrastructure Meta Centrum under the programme of “Projects of Large Research, Development, and Innovations Infrastructures” (CESNETLM2015042) Czech Republic.

Disclosure statement

The authors report there are no competing interests to declare.

Author contributions

Jaymin Parikh: Writing - Original Draft, Investigation, Formal Analysis Nihal Patel: Visualization, Software Keyur Bhatt: Validation, Supervision, Resources Krunal Modi: Supervision, Methodology, Conceptualization Nirali Parmar: Investigation

Scheme 1. Synthesis scheme of TACP.

Additional information

Funding

The authors declare that no funds, grants, or other support were received during the preparation of this manuscript.