Dicoordinate Au(I)–Ethylene Complexes as Hydroamination Catalysts

A series of gold(I)–ethylene  complexes containing a family of bulky phosphine ligands has been prepared. The use of these sterically congested ligands is crucial to stabilize the gold(I)–ethylene bond and prevent decomposition, boosting up their catalytic performance in the highly underexplored hydroamination of ethylene. The precatalysts bearing the most sterically demanding phosphines showed excellent results reaching full conversion to the hydroaminated products under low ethylene pressure (1 bar). Kinetic analysis together with density functional theory (DFT) calculations revealed that the assistance of a second molecule of the nucleophile as a proton shuttle is preferred even when using an extremely congested cavity-shaped Au(I) complex.

Bis{N′-[3-(4-nitrophenyl)-1-phenylprop-2-en-1-ylidene]-N-phenylcarbamimidothioato}zinc(II): crystal structure, Hirshfeld surface analysis and computational study

The title zinc bis(thiosemicarbazone) complex, [Zn(C22H17N4O2S)2], comprises two N,S-donor anions, leading to a distorted tetrahedral N2S2 donor set. The resultant five-membered chelate rings are nearly planar and form a dihedral angle of 73.28 (3)°. The configurations about the endocyclic- and exocyclic-imine bonds are Z and E, respectively, and that about the ethylene bond is E. The major differences in the conformations of the ligands are seen in the dihedral angles between the chelate ring and nitrobenzene rings [40.48 (6) cf. 13.18 (4)°] and the N-bound phenyl and nitrobenzene ring [43.23 (8) and 22.64 (4)°]. In the crystal, a linear supramolecular chain along the b-axis direction features amine-N—H...O(nitro) hydrogen bonding. The chains assemble along the 21-screw axis through a combination of phenyl-C—H...O(nitro) and π(chelate ring)–π(phenyl) contacts. The double chains are linked into a three-dimensional architecture through phenyl-C—H...O(nitro) and nitro-O...π(phenyl) interactions.

6-Chloro-1-({[(2E)-2-methyl-3-phenylprop-2-en-1-yl]oxy}methyl)-1,2,3,4-tetrahydroquinazoline-2,4-dione

In the title compound, C19H17ClN2O3, the conformation about the ethylene bond [1.333 (2) Å] is E. The ten atoms comprising the quinazoline ring are essentially planar (r.m.s. deviation = 0.032 Å) and their mean plane forms a dihedral angle of 13.89 (7)° with the terminal phenyl ring; the molecule has an open conformation as these substituents are directed away from each other. In the crystal, centrosymmetrically related molecules are connected via N—H...O hydrogen bonds between the amide groups, leading to eight-membered {...HNCO}2 synthons. These are consolidated into a three-dimensional architecture by C—H...O, C—H...π and π–π interactions [ring centroid(N2C4)...centroid(C6) distance = 3.5820 (11) Å].

6-Methyl-1-({[(2E)-2-methyl-3-phenylprop-2-en-1-yl]oxy}methyl)-1,2,3,4-tetrahydroquinazoline-2,4-dione

In the title compound, C20H20N2O3, the ten atoms comprising the quinazoline ring are essentially planar (r.m.s. deviation = 0.024 Å), and this plane is almost orthogonal to the terminal phenyl ring [dihedral angle = 82.87 (7)°]. The conformation about the ethylene bond [1.335 (2) Å] is E and there is a significant twist between this residue and the adjacent phenyl ring [C—C—C— torsion angle = −48.4 (3)°]. The crystal structure features centrosymmetric dimeric units linked by pairs of N—H...O hydrogen bonds between the amide groups which lead to eight-membered {...HNCO}2 synthons. These are consolidated into a three-dimensional architecture by C—H...O, C—H...π and π–π interactions [centroid–centroid distances = 3.5087 (8) and 3.5645 (9) Å].

(E,E)-N,N′-Bis(1-phenylethylidene)ethylenediamine

The essentially planar title compound, C18H20N2, is disposed about a center of inversion located at the mid-point of the ethylene bond and features an E configuration about each C=N bond.

Benzazole derivatives, VI: Synthesis of some 2-styrylbenzimidazoles and their quaternization

In this paper an alternative method for obtaining styrylbenzimidazolium iodides was described. Thus, some 1-methyl-2-styrylbenzimidazoles were synthesized by the condensation of 1,2-dimethylbenzimidazoles containing a mono- or di-substituted benzene ring (X = NO2, Br), at their reactive 2-methyl group with aromatic aldehydes by heating at high temperature. Some of the 2-styrylbenzimidazoles were proved to be able to convert into benzimidazolium quaternary iodides by treating them with methyl iodide in an autoclave. The structures of the 2-styrylbenzimidazoles and corresponding iodomethyl derivatives were investigated by IR and 1H-NMR spectral measurements. The obtained compounds are valuable due to their structures of polyenic dyes, with a photoexcitable ethylene bond.