Novel cationic 1,2,4-selenadiazoles: synthesis via addition of 2-pyridylselenyl halides to unactivated nitriles, structures and four-center Se⋯N contacts

Abstract

2-Pyridylselenyl halides undergo facile coupling with a triple CN bond of unactivated nitriles. Unprecedented heterocyclization allowed the preparation of novel class of cationic 1,2,4-selenadiazoles in remarkably high yields. Cationic 1,2,4-selenadiazoles...

Exploring Supramolecular Assembly Space of Cationic 1,2,4-Selenodiazoles: Effect of the Substituent at the Carbon Atom and Anions

“…The structural analysis revealed that dicationic 1,2,4-selenadiazoles in 7 formed [Se–Cl] 2 squares ( Figure 7 ), which we observed earlier [ 22 ]. It should be noted that the second chloride did not participate in ChB ( Figure 7 ).…”

“…), zero or very close to zero energy density (0.000–0.002 a.u.) in these bond critical points (3, –1), and estimated strength for appropriate short contacts (0.9–5.0 kcal/mol) are typical for weak hydrogen bonds [ 3 , 4 , 36 ] and non-covalent interactions involving halogen [ 8 , 9 , 10 , 11 , 12 , 32 , 37 , 38 ] and chalcogen [ 22 , 23 , 39 , 40 , 41 , 42 ] atoms in similar chemical systems. The strongest non-covalent interactions in the studied model supramolecular associates 3 – 10 were chalcogen bonds: Se1···Cl24 in 3 (4.7 kcal/mol), Se1···Cl30 in 4 (4.4 kcal/mol), Se1···Cl38 in 5 (5.0 kcal/mol), Se1···Cl24 in 6 (3.5 kcal/mol), Se29···Cl56 in 7 (5.0 kcal/mol), Se1···Br15 in 8 (3.5 kcal/mol), Se2···C31 in 9 (1.3 kcal/mol), and Se1···F29 (4.7 kcal/mol) in 10 .…”

“…We recently introduced novel cationic 1,2,4-selenodiazole building blocks, which can be easily prepared via the coupling between 2-pyridylselenyl halides and nitriles in high yields [ 22 , 23 ]. In contrast to the exhaustively studied earlier chalcogenodiazoles, the supramolecular chemistry of these novel 1,2,4-selenodiazole is virtually unexplored, but could be a fruitful research field in the near future.…”

2-Pyridylselenenyl versus 2-Pyridyltellurenyl Halides: Symmetrical Chalcogen Bonding in the Solid State and Reactivity towards Nitriles

“…We have recently showcased that the addition of 2-pyridylselenenyl halides to a triple CN bond of unactivated nitriles resulted in the formation of novel cationic 1,2,4-selenadiazoles [11]. Moreover, we showed that the Se atom in the adducts of 2-pyridylselenenyl halides and nitriles could provide two σ-holes and act as a donor ChB (Figure 1).…”

Synthesis and Crystal Structure of the Dirhodium Tetraacetate-Di(cyclohexylisocyanide) Complex

“…Following our interest in CN triple bond activation [1][2][3][4][5][6][7][8][9], here we report the synthesis of dirhodium tetraacetate di(cyclohexylisocyanide) [Rh 2 (O 2 CCH 3 ) 4 (C≡NCy) 2 ] (1) and the evaluation of the Rh(II) ability to activate isocyanides towards nucleophilic addition.…”