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A calorimetric sensor array consisting of designed receptors and metal salts is used for discrimination of structurally similar carboxylic acid analytes. The higher order stoichiometry is used for discussing the preselection as well as preprocessing and they have shown that an addition of only one designed receptor to an array of metal salts has discriminated the structurally similar analytes.

The interplay between the intramolecular B-N dative bonding and solvent insertion in various ortho-methylamino arylboronic acids in protic media is examined. The studies have shown that there is a slight increase in the amount of B-N dative bonding on going from a tertiary to a secondary to a primary amine group, but the solvent insertion has dominated in all cases of the boronate esters.

o-(Pyrrolidinylmethyl)phenylboronic acid and its complexes with bifunctional substrates such as catechol, alpha-hydroxyisobutyric acid, and hydrobenzoin are studied by X-ray crystallography, (super 11)B NMR and computational analysis. It is concluded that in an aprotic solvent where the solvent insertion pathway is absent, an N-B dative bond is usually present in an o-(N,N-dialkylaminomethyl)arylboronate.

o-(Pyrrolidinylmethyl)phenylboronic acid (4) and its complexes with bifunctional substrates such as catechol, α-hydroxyisobutyric acid, and hydrobenzoin have been studied in detail by X-ray crystallography, 11B NMR, and computational analysis. The N–B interactions in analogous boronic acids and esters have been extensively cited in molecular recognition and chemosensing literature. The focal point of this study was to determine the factors that are pertinent to the formation of an intramolecular N–B dative bond. Our structural study predicts that the formation of an N–B dative bond, and/or solvent insertion to afford a tetrahedral boronate anion, depends on the solvent and the complexing substrate present. Specifically, from 11B NMR studies, complexation of 4 with electron-withdrawing and/or vicinally bifunctionalized substrates promotes both the formation of N–B dative bonds and the solvation of sp² boron to a tetrahedral sp³ boronate. In the solid state, the presence of an N–B dative bond in the complex of 4 and catechol (7) depends on the solvent from which it crystallizes. From chloroform, an N–B bond was observed, whereas from methanol, a methoxylated boronate was formed, where the methoxy group is hydrogen-bonded with the neighboring tertiary ammonium ion. The structural optimization of compounds 4 and 7 using density functional theory in a simulated water continuum also predicts that complexation of 4 and catechol promotes either the formation of an N–B bond or solvolysis if 1 equiv of water is present. The conclusion from this study will help in the design of future chemosensing technologies based on o-(N,N-dialkylaminomethyl)-arylboronate scaffolds that are targeting physiologically important substances such as saccharides, α-hydroxycarboxylates, and catecholamines. [ABSTRACT FROM AUTHOR]

A general approach to high-throughput screening of enantiomeric excess (ee) and concentration was developed by using indicator displacement assays (IDAs), and the protocol was then applied to the vicinal diol hydrobenzoin. The method involves the sequential utilization of what we define herein as screening, training, and analysis plates. Several enantioselective boronic acid-based receptors were screened by using 96-well plates, both for their ability to discriminate the enantiomers of hydrobenzoin and to find their optimal pairing with indicators resulting in the largest optical responses. The best receptor/indicator combination was then used to train an artificial neural network to determine concentration and ee. To prove the practicality of the developed protocol, analysis plates were created containing true unknown samples of hydrobenzoin generated by established Sharpless asymmetric dihydroxylation reactions, and the best ligand was correctly identified.