1-Methyl-2,3-dihydro-1H-benzimidazole-2-selone

The title compound C8H8N2Se, is the product of the reaction of 2-chloro-1-methyl­benzimidazole with sodium hydro­selenide. The mol­ecule is almost planar (r.m.s. deviation = 0.041 Å) owing to the presence of the long chain of conjugated bonds (Se=C—NMe—C=C—C=C—C=C—NH). The C=Se bond length [1.838 (2) Å] corresponds well to those found in the close analogs and indicates its pronounced double-bond character. In the crystal, mol­ecules form helicoidal chains along the b axis by means of N—H⋯Se hydrogen bonds

(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, C18H14NSe+·HSO4 −, the cyclo­pentene 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] inter­actions, further consolidate the crystal structure

1,3-Benzothia­zole-2(3H)-selone

The title compound, C7H5NSSe, is the product of the reaction of 2-chloro­benzothia­zole with sodium hydro­selenide. The mol­ecule is almost planar (r.m.s. deviation = 0.018 Å) owing to the presence of the long chain of conjugated bonds (Se=C—N—C=C—C=C—C=C). The geometrical parameters correspond well to those of the analog N-methyl­benzothia­zole-2(3H)-selone, demonstrating that the S atom does not take a significant role in the electron delocalization within the mol­ecule. In the crystal, mol­ecules form centrosymmetric dimers by means of inter­molecular N—H⋯Se hydrogen bonds. The dimers have a nonplanar ladder-like structure. Furthermore, the dimers are linked into ribbons propagating in [010] by weak attractive Se⋯S [3.7593 (4) Å] inter­actions

[Bis(pyridin-2-yl) selenide-κ2N,N′]tetrachloridotin(IV)

The title compound, [SnCl4(C10H8N2Se)], was obtained by the reaction of 2,2′-dipyridyl diselenide with tin tetrachloride. The SnIV ion is coordinated by two N atoms [Sn—N = 2.266 (2) and 2.274 (2) Å] from the bis(2-pyridyl)selenide ligand and four chloride anions [Sn—Cl = 2.3717 (6)–2.3939 (6) Å] in a distorted octahedral geometry. The central six-membered chelate ring has a boat conformation with the Se and Sn atoms deviating by 0.692 (3) and 0.855 (3) Å, respectively, from the mean plane through the remaining four ring atoms. The pyridine rings are inclined to each other by a dihedral angle of 49.62 (8)°. The crystal packing exhibits short intermolecular Se...Cl contacts [3.5417 (7) and 3.5648 (7) Å], weak C—H...Cl hydrogen bonds and π–π stacking interactions between the pyridine rings with a centroid–centroid distance of 3.683 (3) Å

Dichloridobis(pyridine-2-thiolato-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 tetrachloride. The SnIV atom adopts a distorted octahedral geometry, with the two bidentate pyridine-2-thiolate 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 molecule having twofold rotational symmetry, the SnIV atom lying on the twofold axis. The molecular structure of the monoclinic polymorph is very close to that of the triclinic polymorph studied previously in space group P-1, the molecule 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 intermolecular interactions. In the crystal of the monoclinic polymorph, molecules are bound into ribbons along the c axis by C—H...Cl hydrogen bonds, whereas in the crystal of the triclinic polymorph, molecules form chains along the a axis by attractive S...S interactions. The crystal studied was a pseudo-merohedral twin; the refined BASF value is 0.221 (1)

Dichloridobis(pyridine-2-selenolato-κ2N,Se)tin(IV)

The title compound, [SnCl2(C5H4NSe)2], is the product of a reaction of 2,2′-dipyridyl diselenide with tin tetrachloride. The molecule is located about a twofold rotation axis. The coordination environment of the SnIV atom is a distorted octahedron, with two bidentate 2-pyridineselenolate ligands inclined to each other at an angle of 83.96 (7)°. The two Sn—Cl and two Sn—N bonds are in cis configurations, while the two Sn—Se bonds of 2.5917 (3) Å are in a trans configuration, with an Se—Sn—Se angle of 157.988 (15)°. In the crystal, π–π interactions between the pyridine rings [centroid-to-centroid distance of 3.758 (3) Å] and weak intermolecular C—H...Cl hydrogen bonds link the molecules into chains along the c axis