Stability constants of boronic acid diol esters in aqueous solution have been determined potentiometrically for a series of meta-, para-substituted phenylboronic acids and diols of variable acidity. The constants β(11-1) for reactions between neutral forms of reactants producing the anionic ester plus proton follow the Hammett equation with ρ depending on pKa of diol and varying from 2.0 for glucose to 1.29 for 4-nitrocatechol. Observed stability constants (K(obs)) measured by UV-vis and fluorometric titrations at variable pH for esters of 4,5-dihydroxy-1,3-benzenedisulfonate (Tiron) generally agree with those expected on the basis of β(11-1) values, but the direct fitting of K(obs) vs pH profiles gives shifted pKa values both for boronic acids and diol as a result of significant interdependence of fitting parameters. The subsituent effects on absorption and fluorescence spectra of Tiron arylboronate esters are characterized. The K(obs) for Tiron determined by (11)B NMR titrations are approximately 1 order of magnitude smaller than those determined by UV-vis titrations under identical conditions. A general equation, which makes possible an estimate of β(11-1) for any pair of boronic acid and diol from their pKa values, is proposed on the basis of established Brönsted-type correlation of Hammett parameters for β(11-1) with acidity of diols. The equation allows one to calculate stability constants expected only on basis of acid-base properties of the components, thus permitting more strict evaluation of contributions of additional factors such as steric or charge effects to the ester stability.

Abstract1,10‐Diaza‐18‐crown‐6 and 4,4′‐trimethylenedipiperidine were transformed into bis‐dithiocarbamate ligands, which were then reacted in situ with different di‐ and triorganotin(IV) chlorides to generate dinuclear monomeric or macrocyclic products. The identity of the compounds was established by elemental analysis, multinuclear NMR spectroscopy (1H, 13C, and 119Sn), IR spectroscopy, mass spectrometry, and for representative examples additionally by single‐crystal X‐ray diffraction analysis. In combination with DFT calculations, the structural characterization showed that diaryltin and dialkyltin fragments give macrocycles of different conformation owing to changes in the coordination stereochemistry (cis vs. trans isomers). The macrocycle cavities are suitable for the inclusion of guest molecules. At the supramolecular level, the Sn complex molecules are linked through intermolecular C–H···S and C–H···Cl interactions in the solid state.

Highly selective detection of pyrophosphate in the presence of inorganic phosphate, halides, acetate, ATP, other nucleotides and phosphate esters in neutral aqueous solutions is achieved by using fluorescent dimethyltin(iv)-alizarin red S complex.

The reaction of 1,10-diaza-18-crown-6 with CS2 in the presence of a base (MOH or Et3N) generates bis-dithiocarbamate salts with a 1D, 2D or 3D supramolecular solid-state structure based on M–O–M and M–S–M bridging and/or O/N–H⋯O/S hydrogen bonding.