Crystal structure and Hirshfeld surface analysis of 8-benzyl-1-[(4-methyl-phen-yl)sulfon-yl]-2,7,8,9-tetra-hydro-1H-3,6:10,13-diep-oxy-1,8-benzodi-aza-cyclo-penta-decine ethanol hemisolvate.

The asymmetric unit of the title compound, 2C31H28N2O4S·C2H6O, contains a parent mol-ecule and a half mol-ecule of ethanol solvent. The main compound stabilizes its mol-ecular conformation by forming a ring with an R 1 2(7) motif with the ethanol solvent mol-ecule. In the crystal, mol-ecules are connected by C-H⋯O and O-H⋯O hydrogen bonds, forming a three-dimensional network. In addition, C-H⋯π inter-actions also strengthen the mol-ecular packing.

Crystal structure and Hirshfeld surface analysis of dimethyl 4-hy-droxy-5,4'-dimethyl-2'-(toluene-4-sulfonyl-amino)-biphenyl-2,3-di-carboxyl-ate.

In the title compound, C25H25NO7S, the mol-ecular conformation is stabilized by intra-molecular O-H⋯O and N-H⋯O hydrogen bonds, which form S(6) and S(8) ring motifs, respectively. The mol-ecules are bent at the S atom with a C-SO2-NH-C torsion angle of -70.86 (11)°. In the crystal, mol-ecules are linked by C-H⋯O and N-H⋯O hydrogen bonds, forming mol-ecular layers parallel to the (100) plane. C-H⋯π inter-actions are observed between these layers.

Crystal structure and Hirshfeld surface analysis of 4-cyano-N-[(4-cyano-phen-yl)sulfon-yl]-N-[2-(5-methyl-furan-2-yl)phen-yl]benzene-sulfonamide.

In the title compound, C25H17N3O5S2, intra-molecular π-π inter-actions [centroid-to-centroid distance = 3.5640 (9) Å] are observed between the furan and benzene rings of the 4-cyano-phenyl group. In the crystal, mol-ecules are connected via C-H⋯O and C-H⋯N hydrogen bonds, forming layers parallel to the (100) plane. These layers are inter-connected by C-H⋯π inter-actions and weak van der Waals inter-actions. Hirshfeld surface analysis indicates that H⋯H (30.2%), N⋯H/H⋯N (22.3%), C⋯H/H⋯C (17.9%) and O⋯H/H⋯O (15.4%) inter-actions make the most significant contributions to the crystal packing.

Crystal structure and Hirshfeld surface analysis of N-[2-(5-methyl-furan-2-yl)phen-yl]-3-nitro-N-[(3-nitro-phen-yl)sulfon-yl]benzene-sulfonamide.

In the title compound, C23H17N3O9S2, C-H⋯O hydrogen bonds link adjacent mol-ecules in a three-dimensional network, while π-π stacking inter-actions, with centroid-centroid distances of 3.8745 (9) Å, between the furan and an arene ring of one of the two (3-nitro-phen-yl)sulfonyl groups, result in chains parallel to the a axis. The Hirshfeld surface analysis indicates that O⋯H/H⋯O (40.1%), H⋯H (27.5%) and C⋯H/H⋯C (12.4%) inter-actions are the most significant contributors to the crystal packing.

Robust Supramolecular Dimers Derived from Benzylic-Substituted 1,2,4-Selenodiazolium Salts Featuring Selenium⋯π Chalcogen Bonding.

The series of benzylic-substituted 1,2,4-selenodiazolium salts were prepared via cyclization reaction between 2-pyridylselenyl chlorides and nitriles and fully characterized. Substitution of the Cl anion by weakly binding anions promoted the formation supramolecular dimers featuring four center Se2N2 chalcogen bonding and two antiparallel selenium⋯π interactions. Chalcogen bonding interactions were studied using density functional theory calculations, molecular electrostatic potential (MEP) surfaces, the quantum theory of atoms-in-molecules (QTAIM), and the noncovalent interaction (NCI) plot. The investigations revealed fundamental role of the selenium⋯π contacts that are stronger than the Se⋯N interactions in supramolecular dimers. Importantly, described herein, the benzylic substitution approach can be utilized for reliable supramolecular dimerization of selenodiazolium cations in the solid state, which can be employed in supramolecular engineering.

Towards Anion Recognition and Precipitation with Water-Soluble 1,2,4-Selenodiazolium Salts: Combined Structural and Theoretical Study.

The synthesis and structural characterization of a series of supramolecular complexes of bicyclic cationic pyridine-fused 1,2,4-selenodiazoles with various anions is reported. The binding of trifluoroacetate, tetrachloroaurate, tetraphenylborate, perrhenate, and pertechnetate anions in the solid state is regarded. All the anions interact with selenodiazolium cations exclusively via a pair of "chelating" Se⋯O and H⋯O non-covalent interactions, which make them an attractive, novel, non-classical supramolecular recognition unit or a synthon. Trifluoroacetate salts were conveniently generated via novel oxidation reaction of 2,2'-dipyridyl diselenide with bis(trifluoroacetoxy)iodo)benzene in the presence of corresponding nitriles. Isolation and structural characterization of transient 2-pyridylselenyl trifluoroacetate was achieved. X-ray analysis has demonstrated that the latter forms dimers in the solid state featuring very short and strong Se⋯O and Se⋯N ChB contacts. 1,2,4-Selenodiazolium trifluoroacetates or halides show good solubility in water. In contrast, (AuCl4)-, (ReO4)-, or (TcO4)- derivatives immediately precipitate from aqueous solutions. Structural features of these supramolecular complexes in the solid state are discussed. The nature and energies of the non-covalent interactions in novel assembles were studied by the theoretical methods. To the best of our knowledge, this is the first study that regards perrhenate and pertechnetate as acceptors in ChB interactions. The results presented here will be useful for further developments in anion recognition and precipitation involving cationic 1,2,4-selenodiazoles.