Pnicogen, halogen and hydrogen bonds in (E)-1-(2,2-dichloro-1-(2-nitrophenyl)vinyl)-2-(para-substituted phenyl)-diazenes.

Schiff base condensation of 2-nitrobenzaldehyde with ( para -substituted phenyl)hydrazine in the presence of CH 3 COONa in EtOH at 80 °C produces ( E )-1-( para -substituted phenyl)-2-(2-nitrobenzylidene)hydrazines [−OCH 3 ( 1 ), −CH 3 ( 2 ), −H ( 3 ), −Br ( 4 ), −Cl ( 5 ), −F ( 6 )]. CuCl catalyzed olefination of 1 − 6 with CCl 4 in the presence of tetramethylethylenediamine (TMEDA) in DMSO leads to ( E )-1-(2,2-dichloro-1-(2-nitrophenyl)vinyl)-2-( para- substituted phenyl)-diazenes [−OCH 3 ( 7 ), −CH 3 ( 8 ), −H ( 9 ), −Br ( 10 ), −Cl ( 11 ), −F ( 12 )], respectively. 1 – 12 were characterized by 1 H and 13 C NMR spectroscopies, ESI-MS, elemental and X-ray diffraction (for 8 , 9 and 12 ) analysis. The single crystal X-ray analysis of 8 , 9 and 12 evidence the intramolecular N ⋯ Cl pnicogen bonds which is significantly strengthened in view of the planarity of the four atoms involved in the 1,4-membered synthon. The intermolecular halogen and hydrogen bonds also contribute to stabilize the crystal structures of 8 , 9 and 12 . In DMSO solution 1 – 12 exist in the E -isomeric form, which stabilized by inter- and intramolecular noncovalent interactions. Solvatochromic behavior on UV–vis absorption spectra of azo dyes 7 – 12 were studied in CH 2 Cl 2 , DMF and MeOH, which λ max is dependent on the attached substituents at para- position of aromatic moiety. [ABSTRACT FROM AUTHOR]