Palladium(II) Complexes of Bis(diphosphene) with the Different Coordination Behavior

Organophosphorus compounds possessing the P−P double-bond character are intriguing materials in coordination chemistry because it is possible to form a variety of coordination modes from the π-bond in addition to...

From zinco(ii) arsaketenes to silylene-stabilised zinco arsinidene complexes

The steric congestion of a N-heterocyclic silylene promotes the formation of a monomeric As-metallated silylene-arsinidene compound with somewhat double bond character through replacement of CO in the LZn–AsCO precursor (L = β-diketiminate).

The cyclo-Sb6 ring in the [Sb6(RuCp*)2]2− ion

The [Sb6(RuCp*)2]2− anion represents the first example of a Zintl cluster with a boat-like cyclo-Sb6 subunit and the first ruthenium polyantimonide complex. The anion is dynamic in solution and fragments in the gas phase. Structural parameters and DFT calculations suggest the possibility of SbSb double bond character.

Bis(μ-N,N-diallyldithiocarbamato)bis[(N,N-diallyldithiocarbamato)cadmium]

The title compound, [Cd2(C7H10NS2)4], is a neutral dinuclear cadmium(II) complex bearing four bisN,N-diallyldithiocarbamate ligands coordinating to two CdIIcations. In each of the monomeric subunits, there are four S atoms of two dithiocarbamate ligands [Cd—S = 2.5558 (3), 2.8016 (3), 2.6050 (3) and 2.5709 (3) Å] that coordinate to one CdIIatom in a bidentate mode. The dimers are located over an inversion centre bridged by two additional bridging Cd—S bonds [2.6021 (3) Å], leading to a substantial distortion of the geometry of the monomeric subunit from the expected square-planar geometry. The five-coordinate environment around each of the CdIIions in the dimer is best described as substantially tetragonally distorted square pyramidal. The dithiocarbamate groups are themselves planar and are also coplanar with the CdIIions. The negative charge on these groups is delocalized by resonance across the S atoms bound to the CdIIcation. This delocalization of the π electrons in the dithiocarbamate groups also extends to the C—N bonds as they reveal significant double bond character [C—N = 1.3213 (16) and 1.3333 (15) Å].

Ethyl 2-(4-methoxyphenyl)-1-methyl-1H-benzimidazole-5-carboxylate

In the title benzimidazole derivative, C18H18N2O3, the methoxyphenyl ring is twisted with respect to the benzimidazole ring system, making a dihedral angle of 28.81 (5)°. The pendant ethyl chain has an extended conformation. Within the imidazole ring, the C—N single bonds have a partial double-bond character. In the crystal, molecules are linked by weak C—H...π interactions and π–π stacking [the centroid-to-centroid distances being 3.6468 (7), 3.7279 (7) and 3.7481 (7) Å].

4-Fluoro-N-methyl-N-nitroaniline

Molecules of the title compound, C7H7FN2O2, are composed of a nitramine group which is twisted with the respect to the aromatic ring, with an N—N—C—C torsion angle of −117.38 (12)°. In the molecule, the N—N bond length [1.3510 (15) Å] indicates some double-bond character, while the angle between the aromatic ring and the nitramine group rules out further delocalization in the molecule. In the crystal, C—H...F hydrogen bonds connect the molecules intoC11(6) chains along theaaxis. C—H...O hydrogen bonds form, which featureR22(12) loops and further connect these chains.

N-(Pyrazin-2-yl)adamantane-1-carboxamide

Molecules of the title compound, C15H19N3O, are composed of an adamantine unit and a pyrazine ring connected to each other through an amide bond. The H—N—C=O moiety is close to planar [C—N—C—O and C—N—C—C torsion angles of 4.7 (2) and −173.8 (1)°, respectively]. The N3—C5 bond has partial double-bond character [1.370 (1) Å]. The geometries of the pyrazine ring and the adamantane substituent are normal and in good agreement with closely related structures. In the crystal, molecules are connected by N—H...O hydrogen bonds, forming zigzag chains in the [001] direction and are arranged in a herringbone fashion.

N,N,N′,N′,N′′,N′′-Hexamethylguanidinium 1,1,3,3-tetracyanoprop-2-en-1-ide

The asymmetric unit of the title salt, C7H18N3+·C7HN4−, comprises one cation and one anion. TheN,N,N′,N′,N′′,N′′-hexamethylguanidinium ion shows orientational disorder and two sets of N- and C-atom positions were found, with an occupancy ratio of 0.535 (3):0.465 (3). The C—N bond lengths in the guanidinium ion range from 1.339 (16) to 1.35 (2) Å, indicating partial double-bond character pointing towards charge delocalization within the NCN planes. The negative charge in the 1,1,3,3-tetracyanoprop-2-en-1-ide ion is delocalized within the CCC planes with the C—C bonds ranging in length from 1.379 (3) to 1.427 (3) Å, also indicating partial double-bond character.