A look at recent advances in supramolecular analytical chemistry using optical sensing is presented. Topics discussed include single analyte sensing versus differential sensing and types of sensors.
Recently, reversible click reactions have found numerous applications in chemical biology, supramolecular chemistry, and biomedical applications. Boronic acid (BA)-mediated
cis
-diol conjugation is ...one of the best-studied reactions among them. An excellent understanding of the chemical properties and biocompatibility of BA-based compounds has inspired the exploration of novel chemistries using boron to fuel emergent sciences. This topical review focuses on the recent progress of iminoboronate and salicylhydroxamic-boronate constituted reversible click chemistries in the past decade. We highlight the mechanism of reversible kinetics and its applications in chemical biology, medicinal chemistry, biomedical devices, and material chemistry. This article also emphasizes the fundamental reactivity of these two conjugate chemistries with assorted nucleophiles at variable pHs, which is of utmost importance to any stimuli-responsive biological and material chemistry explorations.
Fundamental progress, current developments, and rapidly growing applications of iminoboronate and salicylhydroxamic-boronate conjugate esters are deliberated.
Statistical analysis techniques such as principal component analysis (PCA) and discriminant analysis (DA) have become an integral part of data analysis for differential sensing. These multivariate ...statistical tools, while extremely versatile and useful, are sometimes used as "black boxes". Our aim in this paper is to improve the general understanding of how PCA and DA process and display differential sensing data, which should lead to the ability to better interpret the final results. With various sets of model data, we explore several topics, such as how to choose an appropriate number of hosts for an array, selectivity compared to cross-reactivity, when to add hosts, how to obtain the best visually representative plot of a data set, and when arrays are not necessary. We also include items at the end of the paper as general recommendations which readers can follow when using PCA or DA in a practical application. Through this paper we hope to present these statistical analysis methods in a manner such that chemists gain further insight into approaches that optimize the discriminatory power of their arrays.
By mimicking the mammalian senses of taste and smell, artificial arrays of cross-reactive receptors have found use in a variety of sensing applications. Pattern recognition algorithms allow these ...arrays to be used for discriminating analytes and even for predicting the identity of unknown analytes. Furthermore, in selecting a signaling method for these assays, the choice of optical detection is particularly desirable due to its high sensitivity and the associated convenient instrumentation. This tutorial review provides a brief introduction to array sensing using optical detection and chemometrics. While differential sensing approaches have been used for a number of applications, this review focuses on progress towards the detection of chemical and biological hazards.
A large fraction of the field of supramolecular chemistry has focused in previous decades upon the study and use of synthetic receptors as a means of mimicking natural receptors. Recently, the demand ...for synthetic receptors is rapidly increasing within the analytical sciences. These classes of receptors are finding uses in simple indicator chemistry, cellular imaging, and enantiomeric excess analysis, while also being involved in various truly practical assays of bodily fluids. Moreover, one of the most promising areas for the use of synthetic receptors is in the arena of differential sensing. Although many synthetic receptors have been shown to yield exquisite selectivities, in general, this class of receptor suffers from cross-reactivities. Yet, cross-reactivity is an attribute that is crucial to the success of differential sensing schemes. Therefore, both selective and nonselective synthetic receptors are finding uses in analytical applications. Hence, a field of chemistry that herein is entitled "Supramolecular Analytical Chemistry" is emerging, and is predicted to undergo increasingly rapid growth in the near future.
High-throughput screening (HTS) methods are becoming increasingly essential in discovering chiral catalysts or auxiliaries for asymmetric transformations due to the advent of parallel synthesis and ...combinatorial chemistry. Both parallel synthesis and combinatorial chemistry can lead to the exploration of a range of structural candidates and reaction conditions as a means to obtain the highest enantiomeric excess (ee) of a desired transformation. One current bottleneck in these approaches to asymmetric reactions is the determination of ee, which has led researchers to explore a wide range of HTS techniques. To be truly high-throughput, it has been proposed that a technique that can analyse a thousand or more samples per day is needed. Many of the current approaches to this goal are based on optical methods because they allow for a rapid determination of ee due to quick data collection and their parallel analysis capabilities. In this critical review these techniques are reviewed with a discussion of their respective advantages and drawbacks, and with a contrast to chromatographic methods (180 references).
A new auto‐inductive protocol employs a Meldrum's‐acid‐based conjugate acceptor (1) as a latent source of thiol for signal amplification, as well as optical detection of thiols. The auto‐induction is ...initiated by a thiol‐disulfide exchange that leads to the generation of β‐mercaptoethanol, which in turn decouples the conjugate acceptor to release more thiols, resulting in a self‐propagating cycle that continues until all the conjugate acceptor is consumed. Using 1 in a two‐step integrated protocol yields a rapid, sensitive, and precise diagnostic assay for the ultratrace quantitation of a thiophosphate nerve agent surrogate.
Thiol detection: Combining thiol‐disulfide exchange with decoupling of a conjugate acceptor (1), a new thiol auto‐inductive cascade was developed for signal amplification, as well as colorimetric and fluorometric detection of thiols. Using 1 in a two‐step protocol yields a rapid assay for the ultratrace quantitation of a thiophosphate nerve agent surrogate at ppb levels.
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