Evgeny A. Katayev

Synthesis and study of a new diamidodipyrromethane macrocycle. An anion receptor with a high sulfate-to-nitrate binding selectivityElectronic supplementary information (ESI) available: detailed experimental data and UV-vis spectrophotometric titration data. See http://www.rsc.org/suppdata/cc/b4/b403665d/

A new 2,6-diamidopyridinedipyrromethane hybrid macrocycle () has been synthesized that shows a high selectivity for dihydrogen phosphate and hydrogen sulfate relative to nitrate in acetonitrile solution as judged from UV-vis spectrophotometric titrations; this leads to the suggestion that this or related systems might find use in nuclear waste remediation applications requiring the selective removal of hydrogensulfate from nitrate-rich waste mixtures.

Molecular recognition of pertechnetate and perrhenate

This tutorial review covers the chemistry of artificial receptors designed to recognize the pertechnetate and perrhenate anions. It focuses on the molecular features that give rise to effective and selective complexation. Specific receptor classes are discussed in the context of available solution-phase and solid-state data with differences between pertechnetate and perrhenate binding behavior being highlighted where appropriate.

Supramolecular Chemistry of Environmentally Relevant Anions

Publisher Summary This chapter discusses supramolecular chemistry of environmentally relevant anions. The ultimate goal of the studies on the basic chemical aspects of anion receptor design of functional pH-independent systems is to target selective binding of anions of environmental significance. In applications-oriented aspects of the research on the design of separations, strategies for selective and efficient removal of targeted anions have been a major long-term goal. The chapter discusses (1) some of the first synthetic sulfate-selective anion-binding agents; (2) simple, structure-based methods for modifying the intrinsic anion selectivity of a given class of anion receptors; and (3) the first system capable of extracting sulfate anion from acidic, nitrate-containing aqueous media. These initial findings point the way to more effective systems involving receptors with higher selectivity, binding strength, and solubility. The evolution of anion-binding ligands from simple ammonium-based systems through mixed amide/amine and thioamide/amine receptors is reviewed. Thus, the emphasis is largely on synthetic design strategy carried out in the Bowman–James group.

Expanding sapphyrin: towards selective phosphate binding.

The anion-templated syntheses and binding properties of novel macrocyclic oligopyrrole receptors in which pyrrole rings are linked through amide or imine bonds are described. The efficient synthesis was accomplished by anion-templated [1+1] Schiff-base condensation and acylation macrocyclization reactions. Free receptors and their host-guest complexes with hydrochloric acid, acetic acid, tetrabutylammonium chloride, and hydrogen sulfate were analyzed by single-crystal X-ray diffraction analysis. Stability constants with different tetrabutylammonium salts of inorganic acids were determined by standard 1H NMR and UV/Vis titration techniques in [D6]DMSO/0.5% water solution. According to the titration data, receptors containing three pyrrole rings (10 and 12) exhibit high affinity (log Ka=5-7) for bifluoride, acetate, and dihydrogen phosphate, and interact weakly with chloride and hydrogen sulfate. The amido-bipyrrole receptors 11 and 13 with four pyrrole rings exhibit 10(4)- and 10(2)-fold selectivity for dihydrogen phosphate, respectively, as inferred from competitive titrations in the presence of tetrabutylammonium acetate.

Macrocyclic receptor for pertechnetate and perrhenate anions

The design and synthesis of a neutral macrocyclic host that is capable of perrhenate and pertechnetate recognition is described. The anion affinities and underlying coordination modes were estimated by several experimental and theoretical methods including a new technique--reverse (99)Tc NMR titration.

Anion binding by pyrrole–pyridine-based macrocyclic polyamides

The synthesis, characterisation and anion-binding properties of new pyrrole–pyridine-based macrocyclic polyamides 7a and 7b are presented. Chloride anion templation in the macrocyclisation reaction has been shown to control [1 + 1] acylation. The anion-binding properties of the receptors have been determined by UV–vis titrations in a DMSO solution and compared with systems with a similar design. The new receptors have been found to display a 10-fold selectivity for hydrogensulphate, dihydrogenphosphate and acetate anions over other anions studied.

Mono-palladium(II) complexes of diamidopyridine–dipyrromethane hybrid macrocycles

The reaction of diamidopyridine-dipyrromethane or dipyrromethene hybrid macrocycles with palladium(II) affords mono-metalated complexes, wherein the metal centre is coordinated to the macrocycle exclusively through pyrrolic nitrogen donor atoms.

Insertion of an electron-rich alkyne into a molybdenum amido bond

A pseudo-octahedral molybdenum dimethylamido complex that readily inserts 3-hexyne forming a new C-N bond has been characterized.

Binuclear and polynuclear transition metal complexes with macrocyclic ligands. 4. New polydentate azomethine ligands based on 2,5-diformylpyrrole and 2,6-diformylpyridine

The reactions of 2,5-diformylpyrrole (1) and 2,6-diformylpyridine (2) with propane-1,3-diamine afforded new macrocyclic Schiffs bases 5 and 6, respectively. Their structures were established by NMR spectroscopy and mass spectrometry. Binuclear copper(ii) and nickel(ii) complexes with ligand 5 were synthesized. Pentadentate Schiffs base, viz., 2,6-bis[(2-aminophenylimino)methyl]pyridine, was prepared by demetallation of its complex with Cd(ClO4)2 using Na2S. In solutions, the latter Schiffs base is quantitatively transformed into 2,6-bis(benzoimidazolyl)pyridine under the action of atmospheric oxygen or other mild oxidizing agents.

2,25-Dioxo-27,28-diphenyl-30-oxa-29-thia-3,10,17,24-tetra­aza­penta­cyclo­[24.2.1.112,15.04,9.018,23]triaconta-5,7,9(4),10,12,14,16,18,20,22,26,28-dodeca­ene chloro­form disolvate

The macrocycle of the title compound, C36H24N4O3S·2CHCl3, contains a rigid framework with the nitrogen and oxygen heteroatoms pointing in towards the center of the macrocyclic cavity. The macrocycle is essentially planar (r.m.s. deviation = 0.027 Å) except for the thiophene ring. The dihedral angle between the thiophene ring plane and the mean plane of the central macrocyclic core including all atoms except sulfur is 21.6 (1)°. Four intramolecular hydrogen bonds occur: two are between the amide hydrogen atoms and the Schiff base nitrogen atoms, while the others are between the amide hydrogen atoms and the sulfur atom of the thiophene. The two solvate chloroform molecules are bound to the carbonyl oxygen atoms of the ligand by weak C—H⋯O hydrogen bonding. In addition, the structure reveals intermolecular Cl⋯Cl close contacts [3.308 (2), 3.404 (2) and 3.280 (2) Å] between the chloroform solvate molecules. In the crystal, the macrocycles form layers parallel to (101), with an interlayer distance of 3.362 (3) Å. This short distance is determined by the stacking interactions between the amide carbonyl and imine fragments of neighboring ligands.