New 2,4-dihydro-1H-1,2,4-triazole-3-selones and 3,3'-di(4H-1,2,4-triazolyl)diselenides. Synthesis, biological evaluation, and in silico studies as antibacterial and fungicidal agents.

The reaction of aromatic ring-substituted isoselenocyanates with 2-thiopheacetic and 4-pyridinecarboxylic acid hydrazides yielded selenosemicarbazides which were further converted into previously unknown 1,2,4-triazole-3-selones and 3,3'-di(4H-1, 2,4-triazolyl)diselenides. The structures of the obtained compounds were studied by NMR spectroscopy, IR spectroscopy, and high-resolution mass spectroscopy (HR-MS). The bactericidal and fungicidal activity of some obtained compounds was evaluated in molecular modeling studies such as docking and simulation studies. The compound 3ba was reported as the most promising compound to show robust binding energy with different antibacterial and antifungal compounds. The compounds were observed in strong hydrophilic and hydrophobic interactions and remained in stable binding conformation with the receptor enzymes. Furthermore, the interatomic interaction energies were dominated by Van der Waals and electrostatic energies indicating the formation of stable complexes.

Facile Access to 2-Selenoxo-1,2,3,4-tetrahydro-4-quinazolinone Scaffolds and Corresponding Diselenides via Cyclization between Methyl Anthranilate and Isoselenocyanates: Synthesis and Structural Features.

A practical method for the synthesis of 2-selenoxo-1,2,3,4-tetrahydro-4-quinazolinone was reported. The latter compounds were found to undergo facile oxidation with H2O2 into corresponding diselenides. Novel organoselenium derivatives were characterized by the 1H, 77Se, and 13C NMR spectroscopies, high-resolution electrospray ionization mass spectrometry, IR, elemental analyses (C, H, N), and X-ray diffraction analysis for several of them. Novel heterocycles exhibited multiple remarkable chalcogen bonding (ChB) interactions in the solid state, which were studied theoretically.

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

Correction for 'Novel cationic 1,2,4-selenadiazoles: synthesis via addition of 2-pyridylselenyl halides to unactivated nitriles, structures and four-center Se⋯N contacts' by Victor N. Khrustalev et al., Dalton Trans., 2021, 50, 10689-10691, DOI: 10.1039/D1DT01322J.

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

2-Pyridylselenyl halides undergo facile coupling with a triple CN bond of unactivated nitriles. Unprecedented heterocyclization allowed the preparation of a novel class of cationic 1,2,4-selenadiazoles in remarkably high yields. Cationic 1,2,4-selenadiazoles form supramolecular dimers in the crystal via SeN chalcogen bonding, which was studied theoretically.

Bromination of bis-(pyridin-2-yl) diselenide in methyl-ene chloride: the reaction mechanism and crystal structures of 1H-pyridine-2-selenenyl dibromide and its cyclo-adduct with cyclo-pentene (3aSR,9aRS)-2,3,3a,9a-tetra-hydro-1H-cyclo-penta-[4,5][1,3]selenazolo[3,2-a]pyridinium bromide.

1H-Pyridine-2-selenenyl dibromide, C5H5NSeBr2, 1, is a product of the bromination of bis-(pyridin-2-yl) diselenide in methyl-ene chloride recrystallization from methanol. Compound 1 is essentially zwitterionic: the negative charge resides on the SeBr2 moiety and the positive charge is delocalized over the pyridinium fragment. The C-Se distance of 1.927 (3) Šis typical of a single bond. The virtually linear Br-Se-Br moiety of 178.428 (15)° has symmetrical geometry, with Se-Br bonds of 2.5761 (4) and 2.5920 (4) Å, and is twisted by 63.79 (8)° relative to the pyridinium plane. The Se atom forms an inter-molecular Se⋯Br contact of 3.4326 (4) Å, adopting a distorted square-planar coordination. In the crystal, mol-ecules of 1 are linked by inter-molecular N-H⋯Br and C-H⋯Br hydrogen bonds, as well as by non-covalent Se⋯Br inter-actions, into a three-dimensional framework. (3aSR,(9aRS)-2,3,3a,9a-Tetra-hydro-1H-cyclo-penta[4,5][1,3]selenazolo[3,2-a]pyridinium-9 bromide, C10H12NSe+·Br-, 2, is a product of the cyclo-addition reaction of 1 with cyclo-pentene. Compound 2 is a salt containing a selenazolopyridinium cation and a bromide anion. Both five-membered rings of the cation adopt envelope conformations. The dihedral angle between the basal planes of these rings is 62.45 (11)°. The Se atom of the cation forms two additional non-covalent inter-actions with the bromide anions at distances of 3.2715 (4) and 3.5683 (3) Å, attaining a distorted square-planar coordination. In the crystal, the cations and anions of 2 form centrosymmetric dimers by non-covalent Se⋯Br inter-actions. The dimers are linked by weak C-H⋯Br hydrogen bonds into double layers parallel to (001).

The synthesis and crystal structure of 2-(chloro-selan-yl)pyridine 1-oxide: the first monomeric organoselenenyl chloride stabilized by an intra-molecular secondary Se⋯O inter-action.

The title compound, C5H4ClNOSe, is the product of the reaction of sulfuryl chloride and 2-selanyl-1-pyridine 1-oxide in di-chloro-methane. The mol-ecule has an almost planar geometry (r.m.s. deviation = 0.012 Å), and its mol-ecular structure is stabilized by an intra-molecular secondary Se⋯O inter-action of 2.353 (3) Å, closing a four-membered N-C-Se⋯O ring. The title compound represents the first monomeric organoselenenyl chloride stabilized intra-molecularly by an inter-action of this type. The non-valent attractive Se⋯O inter-action results in a substantial distortion of the geometry of the ipso-carbon atom. The endo-cyclic N-C-Se [102.1 (3)°] and exo-cyclic C-C-Se [136.9 (3)°] bond angles deviate significantly from the ideal value of 120° for an sp2-hybridized carbon atom, the former bond angle being much smaller than the latter. In the crystal, mol-ecules are linked by C-H⋯O hydrogen bonds, forming zigzag chains propagating along [010]. The chains, which stack along the a-axis direction, are linked by offset π-π inter-actions [inter-centroid distance = 3.960 (3) Å], forming corrugated sheets parallel to the ab plane.

3-(4-Meth-oxy-phen-yl)-1,3-selenazolo[2,3-b][1,3]benzo-thia-zol-4-ium hydrogen sulfate.

The title compound, C16H12NOSSe(+)·HSO4 (-), was obtained from a mixture of 3-(4-meth-oxy-phen-yl)[1,3]selenazolo[2,3-b][1,3]benzo-thia-zol-4-ium chloride and potassium hydrogen sulfate. In the cation, the benzene ring is twisted by 71.62 (7)° from the tricycle mean plane. In the crystal, O-H⋯O hydrogen bonds link the anions into chains along [100]. The anions in adjacent chains are linked via weak C-H⋯O hydrogen bonds. The crystal packing exhibits short inter-molecular contacts between the chalcogen unit and the O atoms: Se⋯O(anion) 2.713 (3), Se⋯O(cation) 2.987 (3) and S⋯O(anion) 2.958 (3) Å.

Dichloridobis(pyridine-2-thiol-ato-κ²N,S)tin(IV): a new polymorph.

The title compound, [SnCl2(C5H4NS)2], is the product of reaction of 2,2'-dipyridyl disulfide with tin tetra-chloride. The Sn(IV) atom adopts a distorted octa-hedral geometry, with the two bidentate pyridine-2-thiol-ate ligands forming two planar four-membered chelate rings. The two Sn-Cl, two Sn-N and two Sn-S bonds are in cis, cis and trans configurations, respectively. The crystal grown from acetonitrile represents a new monoclinic polymorph in space group C2/c with the mol-ecule having twofold rotational symmetry, the Sn(IV) atom lying on the twofold axis. The mol-ecular structure of the monoclinic polymorph is very close to that of the triclinic polymorph studied previously in space group P-1, the mol-ecule occupying a general position [Masaki & Matsunami (1976 ▶). Bull. Chem. Soc. Jpn, 49, 3274-3279; Masaki et al. (1978 ▶). Bull. Chem. Soc. Jpn, 51, 3298-3301]. Apparently, the formation of the two polymorphs is determined by the different systems of inter-molecular inter-actions. In the crystal of the monoclinic polymorph, mol-ecules are bound into ribbons along the c axis by C-H⋯Cl hydrogen bonds, whereas in the crystal of the triclinic polymorph, mol-ecules form chains along the a axis by attractive S⋯S inter-actions. The crystal studied was a pseudo-merohedral twin; the refined BASF value is 0.221 (1).

(7aR*,12bS*)-8,12b-Dihydro-7aH-indeno-[1',2':5,6][1,4]selenazino[2,3,4-ij]quinolin-13-ium hydrogen sulfate.

In the title compound, C(18)H(14)NSe(+)·HSO(4) (-), the cyclo-pentene ring in the cation has an envelope conformation while the central six-membered 1,4-selenazine ring adopts a sofa conformation. The dihedral angle between the planes of the terminal benzene rings is 68.08 (11)°. In the crystal, the anions form chains along the c axis through O-H⋯O hydrogen bonds. Weak C-H⋯O and C-H⋯π hydrogen bonds, as well as attractive Se⋯Se [3.5608 (8) Å] inter-actions, further consolidate the crystal structure.