Synthesis, Fluorescence and NMR Spectroscopic Studies of a Novel Phosphinoxido-18-crown-6 Ether Containing an Anthracene Fluorophore Unit

Anna Márton,Csaba Szántay,Dávid Pál,Gergő Dargó,György Tibor Balogh,Hajnalka Szabó-Szentjóbi,Péter Huszthy,Tünde Tóth,Áron Szigetvári

doi:10.3311/ppch.14646

Abstract

The synthesis of the (R,R) and (S,S) enantiomers of a new enantiopure monophospha-18-crown-6 ether (1), which contains an anthracene fluorophore unit and methyl groups at its stereogenic centers, was accomplished. The structure of one enantiomer ((S,S)-1) was studied using one-dimensional (1H, 13C{1H}, and 31P{1H}) and two-dimensional NMR spectra. Because (R,R)-1 and (S,S)-1 can act as new fluorescent chemosensors, we examined their enantiomeric differentiation abilities toward the enantiomers of protonated chiral primary amines and amino acid esters (PEA, 1-NEA, PGME, PAME) using UV-Vis and fluorescence spectroscopies. These monophospha-crown ethers showed moderate enantiomeric discrimination abilities.

Highlights

Molecular recognition is a general phenomenon in Nature
Fluorescent chemosensors that contain a chiral unit and can selectively recognize enantiomers are highly useful in that regard, because they allow for the application of fluorescence spectroscopy, which is an excellent tool owing to its sensitivity, selectivity, versatility and relatively simple handing [5]
In this paper we report the preparation of the (R,R) and (S,S) enantiomers of a new monophospha-18-crown-6 ether (1) containing an anthracene fluorophore unit, and having methyl groups at its stereogenic centers. [Note that the (R,S) and (S,R) forms involve diastereomeric as well as homomeric relationships if one considers the configuration of the P atom]

Summary

Introduction

There are many examples of its action, such as the enzyme-substrate interaction or the immunological response These interactions are governed by non-covalent intermolecular forces between the host and the guest molecules [1,2,3,4]. The determination of enantiomeric compositions of biologically active chiral compounds has great importance, because the enantiomers may have very different physiological properties. Chiral ‘hosts’ that can differentiate between enantiomeric guest molecules via some form of molecular recognition are always sought for, since they play an essential role in the analytical methods developed for the identification of enantiomers and the determination of enantiomeric ratios in non-racemic compositions. Optically active crown ethers containing various fluorophore units were synthesized and their enantiomeric recognition abilities toward different chiral organic ammonium salts were examined [6]. Earlier we reported the preparation and evaluation of enantiopure crown ethers containing a pyridine or an acridine moiety or BODIPY linked azacrown ethers [7,8,9,10,11,12]

Objectives

Methods

Results

Conclusion