title: X-ray crystallographic, spectroscopic and quantum chemical studies on ethyl 2-cyano-3-N ,N-dimethyl amino acrylate.
abstract: Structural and spectral characteristics of ethyl 2-cyano-3-N,N-dimethyl amino acrylate have been studied by methods of X-ray crystallography, infrared spectroscopy and quantum chemistry. The compound crystallizes in monoclinic space group P2(1)/n with unit cell parameters a=4.26(1)A, b=11.16(1)A, c=19.63(3)A and beta=95.5(1) degrees . The X-ray based three-dimensional structure analysis has been carried out by direct methods and fully refined. Density functional theory calculations for potential energy curves, optimized geometries and vibrational spectra have been carried out using 6-31 G and 6-31 G basis sets and B3LYP functionals. These suggest the possibility of existence of two structural isomers for the molecule-a more stable s-cis and a less stable s-trans isomer, having enthalpy difference of 2.85 kcal/mol. The optimized molecular geometry is in agreement with experimental geometry from X-ray analysis and suggests a preferential s-cis conformation for the molecule in the solid state. Based on experimental and theoretical studies, it may be concluded that the molecule has an almost planar conformation with the cyanide group also lying in the molecular plane; the deviation from planarity does not exceed 3 degrees . The structure is stabilized by the presence of intra-molecular and inter-molecular interactions.
authors.affiliation: Spectroscopy Laboratory, Department of Physics, University of Jammu, Jammu-Tawi 180006, India. vpgpt1@yahoo.co.in
authors.forename: V P
authors.initials: VP
authors.lastname: Gupta
authors.forename: Archna
authors.initials: A
authors.lastname: Sharma
authors.lastname: Dinesh
authors.lastname: Rajnikant
mesh_terms: D018360:Crystallography, X-Ray; D003487:Cyanoacrylates / Q000737:chemistry*; D008968:Molecular Conformation; D011789:Quantum Theory; D017550:Spectroscopy, Fourier Transform Infrared; D013237:Stereoisomerism; D013816:Thermodynamics
chemical_list: D003487:Cyanoacrylates