Chiral Recognition by Supramolecular Porphyrin–Hemicucurbit[8]uril-Functionalized Gravimetric Sensors

Abstract

Enantiorecognition of a chiral analyte usually requires the ability to respond with high specificity to one of the two enantiomers of a chiral compound. However, in most cases, chiral sensors have chemical sensitivity toward both enantiomers, showing differences only in the intensity of responses. Furthermore, specific chiral receptors are obtained with high synthetic efforts and have limited structural versatility. These facts hinder the implementation of chiral sensors in many potential applications. Here, we utilize the presence of both enantiomers of each receptor to introduce a novel normalization that allows the enantio-recognition of compounds even when single sensors are not specific for one enantiomer of a target analyte. For this purpose, a novel protocol that permits the fabrication of a large set of enantiomeric receptor pairs with low synthetic efforts by combining metalloporphyrins with (R,R)- and (S,S)-cyclohexanohemicucurbit­[8]­uril is developed. The potentialities of this approach are investigated by an array of four pairs of enantiomeric sensors fabricated using quartz microbalances since gravimetric sensors are intrinsically non-selective toward the mechanism of interaction of analytes and receptors. Albeit the weak enantioselectivity of single sensors toward limonene and 1-phenylethylamine, the normalization allows the correct identification of these enantiomers in the vapor phase indifferent to their concentration. Remarkably, the achiral metalloporphyrin choice influences the enantioselective properties, opening the way to easily obtain a large library of chiral receptors that can be implemented in actual sensor arrays. These enantioselective electronic noses and tongues may have a potential striking impact in many medical, agrochemical, and environmental fields.

Porphyrin-Based Hybrid Nanohelices: Cooperative Effect between Molecular and Supramolecular Chirality on Amplified Optical Activity

“…In this context, our focus is to develop chiral chemical sensors based on rationally designed sensing materials, intending to fill the existing gap between the production of enantioselective receptors and the realization of macroscopic devices being able to work in real scenarios. As an example of such sensors, we have recently reported that sensing layers consisting of metalloporphyrins combined with chiral cyclohexanohemicucurbit [8]urils deposited on quartz microbalances efficiently recognize vapor samples of limonene and 1-phenylethylamine enantiomers by application of a novel normalization procedure and multivariate analysis techniques to improve the classification performances. 8 In this paper, we report new chiral nanosystems by integrating porphyrin-based receptors into silica nanohelices.…”

“…As an example of such sensors, we have recently reported that sensing layers consisting of metalloporphyrins combined with chiral cyclohexanohemicucurbit [8]urils deposited on quartz microbalances efficiently recognize vapor samples of limonene and 1-phenylethylamine enantiomers by application of a novel normalization procedure and multivariate analysis techniques to improve the classification performances. 8 In this paper, we report new chiral nanosystems by integrating porphyrin-based receptors into silica nanohelices. Indeed, nanoscale siliceous materials offer a number of potential advantages for sensing applications, thanks to their stable structural and functional properties, 9−11 also in combination with organic dyes like porphyrins.…”

Stereoselective Interaction between Chiral Carbon Dots and Chiral Ligands for Developing Chiral Sensing Devices

“…Chirality is fundamental to molecules and nature, which plays a crucial role in various biological processes, chiral separation, chiral detection, chiral recognition, and asymmetric catalysis . Although chirality at the molecular level is well studied, however, transferring chirality from the molecular level to nanomaterials has opened up cutting-edge research areas in chiral nanomaterials. , Incorporating chirality in nanomaterials makes them unique candidates for biological sensing, photonics, and fabrication of spin-polarized optoelectronic devices .…”

Hemicucurbituril-Porphyrin Supramolecular Systems for Pollutant Sensing and Remediation

“…Chirality sensing adds another viewpoint to sensing systems, and we have shown that toxic organocatalysts can be sensed via complex formation with Zn porphyrins [6]. By merging chiral hemicucurbiturils and metalloporphyrins via noncovalent interactions into a solid thin material, one can construct an enantioselective electronic nose and very selectively discriminate different analytes and their handedness [7]. In this conference, we will present our findings on how hemicucurbiturils and porphyrins, as supramolecular receptors, can be employed for optical and gravimetric sensing, as well as for the remediation of chemical pollutants.…”