Donor–Acceptor Complexes between 1,2,5‐Chalcogenadiazoles (Te, Se, S) and the Pseudohalides CN⁻and XCN⁻(X=O, S, Se, Te)

Abstract

Donor-acceptor (D-A) complexes between 3,4-dicyano-1,2,5-chalcogenadiazoles [chalcogen=Te (1 a), Se (1 b), S (1 c)] and the pseudohalides CN and XCN (X=O, S, Se, Te) were studied experimentally and theoretically. For 1 a, they were isolated as [K(18-crown-6)][1 a-CN] (2), [K(18-crown-6)][1 a-NCO] (3), [K(18-crown-6)][1 a-SCN] (4), [K(18-crown-6)][1 a-SeCN] (5), and [K][1 a-NCSe] (6) and characterized by X-ray diffraction (XRD), UV/Vis and NMR spectroscopy, and DFT and QTAIM calculations. For 1 b and 1 c, the complexes were not isolated due to unfavorable thermodynamics. In all isolated complexes, the D-A bonds, stabilized by negative hyperconjugation, were longer than the sum of the covalent radii and shorter than the sum of the van der Waals radii of the bonded atoms. In mixtures of 1 a, F , and SeCN , the complex [1 a-F] was selectively formed in accordance with thermodynamics. The reaction of 1 a with SeCN and the cyclic trimeric perfluoro-ortho-phenylene mercury afforded the complex [K(18-crown-6)][SCN]⋅(o-C F Hg) , which was characterized by XRD.

Radical Anions, Radical‐Anion Salts, and Anionic Complexes of 2,1,3‐Benzochalcogenadiazoles

“…Despite the wide variety of ligand binding modes of polychalcogenide anions, their coordination to neutral species was never observed . Overall, the findings of this work highlight the general character of the D–A interactions between Lewis bases and 1,2,5‐chalcogenadiazole derivatives, attract additional attention to chalcogen interactions towards anion recognition and transport, and create new possibilities. One can think that numerous other polychalcogenide (S, Se, Te) anions, as well as many other anions, could also be involved in D–A interactions with chalcogen atoms of various members of the 1,2,5‐chalcogenadiazole family.…”

Synthesis and Applications of 5‐Membered Chalcogen‐Nitrogen π‐Heterocycles with Three Heteroatoms

“…The wide disparity in the energies of the DA bonds implies a possibility of selective interactions. Those were really observed for a mixture of 3,4‐dicyano‐1,2,5‐telluradiazole with F − and SeCN − where a selective formation of DA complex with F − was detected by variable‐temperature multinuclear NMR . In the future, CT bands in the Vis spectra of the complexes can be employed for sensing.…”

Strongσ‐Hole Activation on Icosahedral Carborane Derivatives for a Directional Halide Recognition

“…[10][11][12][13][14][15] Moreover,molecules involving two activated chalcogen atoms have been used to chelate aLewis base,inthe field of organocatalysis or anion recognition. [16][17][18][19][20] Despite those observations and discoveries,h arnessing the ChB for crystal engineering remains challenging due to the presence of two s-holes that can significantly deviate from the CÀCh bond axis, [21,22] in contrast to monotopic and directional XB.…”