title: Crystal structure, vibrational spectra and DFT simulations of 2-fluoro-4-bromobenzaldehyde.
abstract: Molecular structure and properties of 2-fluoro-4-bromobenzaldehyde (FBB, C7H4BrFO) was experimentally investigated by X-ray diffraction technique and vibrational spectroscopy. Experimental results on the molecular structure of FBB were supported with computational studies using the density functional theory, with the Becke-3-Lee-Yang-Parr functional and the 6-311+G(3df,p) basis set. Molecular dimer formed by the intermolecular hydrogen bonding was investigated. Potential energy distribution analysis of normal modes was performed to identify characteristic frequencies. FBB crystallizes in orthorhombic space group P2(1)2(1)2(1) with the O-trans conformation. In order to investigate halogen effect, the chloro- (CBB) and bromo- (BBB) analogs of FBB have also been studied theoretically. It is observed that all compounds prefer the stable O-trans conformation. Although the free energy difference between the O-cis and O-trans conformers is less than 2.5 kcal/mol, the free energy rotational barrier is at least 7.4 kcal/mol. There is a good agreement between the experimentally determined structural parameters, and vibrational frequencies of FBB and those predicted theoretically.
authors.affiliation: Department of Physics, Dumlupinar University, Kütahya 43100, Turkey.
authors.forename: Mahir
authors.initials: M
authors.lastname: Tursun
authors.affiliation: X-ray Crystallography Unit, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia; Department of Engineering Chemistry, Alva's Institute of Engineering & Technology, Mijar, Moodbidri 574225, Karnataka, India. Electronic address: chidankumar@gmail.com.
authors.forename: Chandraju Sadolalu Chidan
authors.initials: CS
authors.lastname: Kumar
authors.affiliation: Department of Physics, Science Faculty, Ege University, İzmir 35100, Turkey.
authors.forename: Metin
authors.initials: M
authors.lastname: Bilge
authors.affiliation: Computational Chemistry Group, Department of Chemistry, Faculty of Science, University of Mauritius, Réduit 8083, Mauritius.
authors.forename: Lydia
authors.initials: L
authors.lastname: Rhyman
authors.affiliation: X-ray Crystallography Unit, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia; Department of Pharmaceutical Chemistry, College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia.
authors.forename: Hoong Kun
authors.initials: HK
authors.lastname: Fun
authors.affiliation: Department of Physics, Dumlupinar University, Kütahya 43100, Turkey.
authors.forename: Cemal
authors.initials: C
authors.lastname: Parlak
authors.affiliation: Computational Chemistry Group, Department of Chemistry, Faculty of Science, University of Mauritius, Réduit 8083, Mauritius.
authors.forename: Ponnadurai
authors.initials: P
authors.lastname: Ramasami
authors.affiliation: Department of Sugar Technology and Chemistry, Sir M. Visvesvaraya PG Center, University of Mysore, Tubinakere, Mandya 571402, India.
authors.forename: Siddegowda
authors.initials: S
authors.lastname: Chandraju
authors.affiliation: X-ray Crystallography Unit, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia.
authors.forename: Ching Kheng
authors.initials: CK
authors.lastname: Quah
mesh_terms: D001547:Benzaldehydes / Q000737:chemistry*; D018360:Crystallography, X-Ray; D006842:Hydrocarbons, Brominated / Q000737:chemistry*; D006843:Hydrocarbons, Chlorinated / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D001547:Benzaldehydes; D006842:Hydrocarbons, Brominated; D006843:Hydrocarbons, Chlorinated; C032175:benzaldehyde
keywords: 2-Fluoro-4-halogenobenzaldehyde; Crystal structure; DFT; Vibrational spectra; XRD