3-Iodobenzaldehyde: XRD, FT-IR, Raman and DFT studies

Kumar CS 1 , Parlak C 2 , Tursun M 2 , Fun HK 3 , Rhyman L 4 , Ramasami P 5 Show all authors , Alswaidan IA 6 , Keşan G 7 , Chandraju S 8 , Quah CK 9

Affiliations 

  • 1 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, Modbidri, 574225, Karnataka, India
  • 2 Department of Physics, Dumlupinar University, Kütahya 43100, Turkey
  • 3 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
  • 4 Computational Chemistry Group, Department of Chemistry, Faculty of Science, University of Mauritius, Réduit 80837, Mauritius
  • 5 Department of Pharmaceutical Chemistry, College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia; Computational Chemistry Group, Department of Chemistry, Faculty of Science, University of Mauritius, Réduit 80837, Mauritius. Electronic address: [email protected]
  • 6 Department of Pharmaceutical Chemistry, College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia
  • 7 Institute of Physics and Biophysics, Faculty of Science, University of South Bohemia, Branišovská 31, České Budějovice 370 05, Czech Republic
  • 8 Department of Sugar Technology and Chemistry, Sir M. Visvesvaraya PG Center, University of Mysore, Tubinakere, Mandya 571402, India
  • 9 X-ray Crystallography Unit, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia
Spectrochim Acta A Mol Biomol Spectrosc, 2015 Jun 15;145:90-7.
PMID: 25767992 DOI: 10.1016/j.saa.2015.02.079

Abstract

The structure of 3-iodobenzaldehyde (3IB) was characterized by FT-IR, Raman and single-crystal X-ray diffraction techniques. The conformational isomers, optimized geometric parameters, normal mode frequencies and corresponding vibrational assignments of 3IB were examined using density functional theory (DFT) method, with the Becke-3-Lee-Yang-Parr (B3LYP) functional and the 6-311+G(3df,p) basis set for all atoms except for iodine. The LANL2DZ effective core basis set was used for iodine. Potential energy distribution (PED) analysis of normal modes was performed to identify characteristic frequencies. 3IB crystallizes in monoclinic space group P21/c with the O-trans form. There is a good agreement between the theoretically predicted structural parameters, and vibrational frequencies and those obtained experimentally. In order to understand halogen effect, 3-halogenobenzaldehyde [XC6H4CHO; X=F, Cl and Br] was also studied theoretically. The free energy difference between the isomers is small but the rotational barrier is about 8kcal/mol. An atypical behavior of fluorine affecting conformational preference is observed.

* Title and MeSH Headings from MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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