Solid-State Examination of Conformationally Diverse Sulfonamide Receptors Based on Bis(2-anilinoethynyl)pyridine, -Bipyridine, and -Thiophene

Antifungal Application of Rosin Derivatives from Renewable Pine Resin in Crop Protection

In the current work, we synthesized two series of dehydroabietyl amide derivatives from natural product rosin and evaluated their antifungal effects on Valsa mali, Phytophthora capsici, Botrytis cinerea, Sclerotinia sclerotiorum, and Fusarium oxysporum. In vitro and in vivo antifungal activities results indicated that rosin-based amide compounds containing thiophene heterocycles had better inhibitory effects on B. cinerea. In particular, compound 5b (5-fluoro-2-thiophene dehydroabietyl amide) exhibited the excellent antifungal properties against B. cinerea with an EC₅₀ of 0.490 mg/L, which was lower compared to the positive control penthiopyrad (0.562 mg/L). Physiological and biochemical studies showed that the primary action mechanism of compound 5b on B. cinerea changes mycelial morphology, increases cell membrane permeability, and inhibits the TCA pathway in respiratory metabolism. Furthermore, QSAR and SAR studies revealed that charge distribution of rosin-based amides derivatives have a key role in the antifungal activity through the hydrogen bonding, conjugation, and electrostatic interaction between the compounds and the receptors of the target. To sum up, this study contributes to the development of rosin-based antifungal agents with a novel structure and preferable biological activity.

Anion Influence on the Packing of 1,3-Bis(4-Ethynyl-3-Iodopyridinium)-Benzene Halogen Bond Receptors

Rigid and directional arylethynyl scaffolds have been widely successful across diverse areas of chemistry. Utilizing this platform, we present three new structures of a dicationic 1,3-bis(4-ethynyl-3-iodopyridinium)-benzene halogen bonding receptor with tetrafluoroborate, nitrate, and hydrogen sulfate. Structural analysis focuses on receptor conformation, anion shape, solvation, and long range packing of these systems. Coupled with our previously reported structures, we conclude that anions can be classified as building units within this family of halogen bonding receptors. Two kinds of antiparallel dimers are observed for these dicationic receptors. An off-centered species is most frequent, present among geometrically diverse anions, and assorted receptor conformations. In contrast, the centered antiparallel dimers are observed with receptors adopting a bidentate conformation in the solid-state. While anions support the solid-state formation of dimers, the molecular geometry and characteristics (planarity, rigidity, and directionality) of arylethynyl systems increases the likelihood of dimer formation by limiting efficient packing arrangements. The significantly larger cation may have considerable influence on the solid-state packing, as similar cationic arylethynyl systems also display these dimers, suggesting.

Harnessing solid-state packing for selective detection of chloride in a macrocyclic anionophore

We report the synthesis of an inherently fluorescent macrocyclic receptor for chloride. The use of a disulphide tether provides for an excellent yield in the macrocyclization step. This compound binds chloride in the solution and solid state, and while unstable over time in aqueous solution, shows a selective response toward chloride over other anions in the solid state due to intermolecular interactions between fluorophore backbones. Surprisingly, the optoelectronic response to anions differs in solution and the films, with a distinct colorimetric response observed only in the film.

Anion-directed self-assembly of a 2,6-bis(2-anilinoethynyl)pyridine bis(amide) scaffold

Bis(sulfonamide) receptors based on the 2,6-bis(2-anilinoethynyl)pyridine scaffold form persistent dimers with water and halides in solution and in the solid-state. The structurally related bis(amide) receptor derived from 3,5-dinitrobenzoyl chloride is a dimer in the solid-state with two HCl molecules directing the self-assembly. The 2+2 dimer, with a twisted "S"-shaped backbone, is held together by six hydrogen bonds. Dissolution of the (H2⁺·Cl^- )₂ adduct in CHCl₃ results, however, in a monomeric structure. DOSY and ¹H NMR experiments were used to identify the dominance of monomer in solution for both 2 and H2⁺·Cl^- . The 'OFF-ON' fluorescence response of 2, 6-bis(2-anilinoethynyl)pyridine is retained with amide arms.

Protonation and Alkylation Induced Multidentate C-H•••Anion Binding to Perrhenate

A family of pyridyl functionalized arylacetylene C-H HB receptors were synthesized and binding interactions to perrhenate (ReO₄ ^-) studied in the solid state. The protonation and alkylation state of the pyridine nitrogen dictate the location and denticity of the interactions. X-ray structures of neutral 1 and singly charged 2a⁺•ReO₄ ^- reveal the formation of favorable self-complimentary dimers, owning to the presence of nitrogen HB acceptor sites. Dismissal of these dimers upon elimination of nitrogen HB acceptors on the receptor result in an array of multidentate C-H HB receptor-guest contacts.