Karabiyik, HasanPetek, HandeIskeleli, Nazan OcakAlbayrak, Cigdem2025-03-232025-03-2320091040-04001572-9001https://doi.org/10.1007/s11224-009-9490-4https://hdl.handle.net/11486/6857The molecular and crystal structure of (E)-2-Acetyl-4-(2-bromophenyldiazenyl)phenol (1) and (E)-2-Methyl-4-(o-tolyldiazenyl)phenol (2) were characterized and determined by single crystal X-ray diffraction method besides spectroscopic means. The periodic organization of 1 is stabilized by C-H center dot center dot center dot O type weak H-bond and Br center dot center dot center dot O type weak halogen bonding and thus, a two dimensional puckered network is established almost parallel to 10((1) over bar) the plane. Molecules of 2 are linked into C(7) chains generated by translation along the [1 0 1] direction with the aid of O-H center dot center dot center dot N type H-bonds, and these chains are strengthened by C-H center dot center dot center dot pi interactions involving o-tolylphenol ring. Quantum chemical studies at B3LYP/6-311 ++G(d,p) level reveal that potential barrier of the compounds around Ar-N torsions is of double minimum character unless it is defected by the presence of o-substituent groups in the vicinity of the azo bridge. The results from crystallographic and quantum chemical studies suggest that azo benzene compounds may adapt non-planar geometry apart from the most stable planar conformation, which is located on the secondary minima of double potential barrier regarding rotational motion around Ar-N bonds.eninfo:eu-repo/semantics/closedAccessAzo benzeneDFT/B3LYPConformational analysisCrystal structureArticle20590391010.1007/s11224-009-9490-42-s2.0-70349883689Q2WOS:000268773900020Q2