Computational exploration of the copper(I)-catalyzed conversion of hydrazones to dihalogenated vinyldiazene derivatives.

This computational study explores the copper (I) chloride catalyzed synthesis of (E)-1-(2,2-dichloro-1-phenylvinyl)-2-phenyldiazene (2Cl-VD) from readily available hydrazone derivative and carbon tetrachloride (CCl4). 2Cl-VD has been extensively utilized to synthesize variety of heterocyclic organic compounds in mild conditions. The present computational investigations primarily focus on understanding the role of copper (I) and N1,N1,N2,N2-tetramethylethane-1,2-diamine (TMEDA) in this reaction, TMEDA often being considered a proton scavenger by experimentalists. Considering TMEDA as a ligand significantly alters the energy barrier. In fact, it is only 8.3 kcal/mol higher compared to the ligand-free (LF) route for the removal of a chlorine atom to form the radical ·CCl3 but the following steps are almost barrierless. This intermediate then participates in attacking the electrophilic carbon in the hydrazone. Crucially, the study reveals that the overall potential energy surface is thermodynamically favorable, and the theoretical turnover frequency (TOF) value is higher in the case of Cu(I)-TMEDA complex catalyzed pathway.

Crystal structure and Hirshfeld surface analysis of 3-[2-(3,5-di-methyl-phen-yl)hydrazinyl-idene]benzo-furan-2(3H)-one.

In the title compound, C16H14N2O2, the 2,3-di-hydro-1-benzo-furan ring system is essentially planar and makes a dihedral angle of 3.69 (7)° with the di-methyl-phenyl ring. The mol-ecular conformation is stabilized by an intra-molecular N-H⋯O hydrogen bond with an S(6) ring motif. In the crystal, mol-ecules are connected by C-H⋯π and π-π stacking inter-actions, forming a layer lying parallel to the (11) plane. One methyl group is disordered over two orientations, with occupancies of 0.67 (4) and 0.33 (4). Hirshfeld surface analysis indicates that the most important contributions to the crystal packing are from H⋯H (51.2%), O⋯H/H⋯O (17.9%), C⋯H/H⋯C (15.2%) and C⋯C (8.1%) contacts.

Crystal structure and Hirshfeld surface analysis of (3Z)-7-meth-oxy-3-(2-phenyl-hydrazinyl-idene)-1-benzo-furan-2(3H)-one.

In the title compound, C15H12N2O3, pairs of mol-ecules are linked into dimers by N-H⋯O hydrogen bonds, forming an R 2 2(12) ring motif, with the dimers stacked along the a axis. These dimers are connected through π-π stacking inter-actions between the centroids of the benzene and furan rings of their 2,3-di-hydro-1-benzo-furan ring systems. Furthermore, there exists a C-H⋯π inter-action that consolidates the crystal packing. A Hirshfeld surface analysis indicates that the most important contacts are H⋯H (40.7%), O⋯H/H⋯O (24.7%), C⋯H/H⋯C (16.1%) and C⋯C (8.8%).

Crystal structure and Hirshfeld surface analysis of (2Z)-N,N-dimethyl-2-(penta-fluoro-phen-yl)-2-(2-phenyl-hydrazin-1-yl-idene)acetamide.

In the title compound, C16H12F5N3O, the dihedral angle between the aromatic rings is 31.84 (8)°. In the crystal, the mol-ecules are linked into dimers possessing crystallographic twofold symmetry by pairwise N-H⋯O hydrogen bonds and weak C-H⋯O hydrogen bonds and aromatic π-π stacking inter-actions link the dimers into a three-dimensional network. A Hirshfeld surface analysis indicates that the most important contributions to the crystal packing are from F⋯H/H⋯F (41.1%), H⋯H (21.8%), C⋯H/H⋯C (9.7%) C⋯C (7.1%) and O⋯H/H⋯O (7.1%) contacts. The contribution of some disordered solvent to the scattering was removed using the SQUEEZE routine [Spek (2015 ▸). Acta Cryst. C71, 9-18] in PLATON. The solvent contribution was not included in the reported mol-ecular weight and density.

Crystal structure and Hirshfeld surface analysis of (E)-4-{2,2-di-chloro-1-[(3,5-di-methyl-phen-yl)diazen-yl]ethen-yl}-N,N-di-methyl-aniline.

In the title compound, C18H19Cl2N3, the planes of the benzene rings subtend a dihedral angle of 77.07 (10)°. In the crystal, mol-ecules are associated into inversion dimers via short Cl⋯Cl contacts [3.3763 (9) Å]. A Hirshfeld surface analysis indicates that the most important contact percentages for the different types of inter-actions are H⋯H (43.9%), Cl⋯H/H⋯Cl (22.9%), C⋯H/H⋯C (20.8%) and N⋯H/H⋯N (8.0%).

Crystal structure and Hirshfeld surface analysis of 4-{2,2-di-chloro-1-[(E)-2-(4-methyl-phen-yl)diazen-1-yl]ethen-yl}-N,N-di-methyl-aniline.

In the tile compound, C17H17Cl2N3, the dihedral angle between the benzene rings is 62.73 (9)°. In the crystal, there are no classical hydrogen bonds. Mol-ecules are linked by a pair of C-Cl⋯π inter-actions, forming an inversion dimer. A short inter-molecular HL⋯HL contact [Cl⋯Cl = 3.2555 (9) Å] links the dimers, forming a ribbon along the c-axis direction. The Hirshfeld surface analysis and two-dimensional fingerprint plots reveal that the most important contributions for the crystal packing are from H⋯H (45.4%), Cl⋯H/H⋯Cl (21.0%) and C⋯H/H⋯C (19.0%) contacts.

Crystal structure and Hirshfeld surface analysis of 4-{2,2-di-chloro-1-[(E)-(4-fluoro-phen-yl)diazen-yl]ethen-yl}-N,N-di-methyl-aniline.

In the title compound, C16H14Cl2FN3, the dihedral angle between the two aromatic rings is 64.12 (14)°. The crystal structure is stabilized by a short Cl⋯H contact, C-Cl⋯π and van der Waals inter-actions. The Hirshfeld surface analysis and two-dimensional fingerprint plots show that H⋯H (33.3%), Cl⋯H/H⋯Cl (22.9%) and C⋯H/H⋯C (15.5%) inter-actions are the most important contributors towards the crystal packing.

Crystal structure and Hirshfeld surface analysis of (E)-4-{[2,2-di-chloro-1-(4-meth-oxy-phen-yl)ethen-yl]diazen-yl}benzo-nitrile.

In the title compound, C16H11Cl2N3O, the 4-meth-oxy-substituted benzene ring makes a dihedral angle of 41.86 (9)° with the benzene ring of the benzo-nitrile group. In the crystal, mol-ecules are linked into layers parallel to (020) by C-H⋯O contacts and face-to-face π-π stacking inter-actions [centroid-centroid distances = 3.9116 (14) and 3.9118 (14) Å] between symmetry-related aromatic rings along the a-axis direction. A Hirshfeld surface analysis indicates that the most important contributions to the crystal packing are from Cl⋯H/H⋯Cl (22.8%), H⋯H (21.4%), N⋯H/H⋯N (16.1%), C⋯H/H⋯C (14.7%) and C⋯C (9.1%) inter-actions.