128729-12-4Relevant academic research and scientific papers
Crystal Structure and Nuclear Quadrupole Resonance. The Bond Length C-Cl and 35Cl NQR
Brummer, Stefanie,Weiss, Alarich
, p. 497 - 513 (2007/10/02)
The intramolecular distances dC-Cl for chlorine bound to sp2 carbon and to sp3 carbon, respectively, and the 35Cl NQR frequencies assigned to the corresponding Cl atoms correlate quite well according to the theory: ν(35Cl) ca. (dC-Cl)-3.The relation is ν(35Cl) = (4 +/- 6) MHz + (166 +/- 31)*1E6*(dC-Cl)-3* MHz*pm3 for 2-C>-Cl and ν(35Cl) = (21 +/- 5) MHz + (101 +/- 25) *1E6 * (dC-Cl)-3 *MHz * pm3 for 3-C>-Cl.The crystal structures and chemical bonds of (1) (4-methyl-4-trichloromethyl-2,5-cyclohexadiene-1-one), (2) (2-chloro-4,5-dimethyl-4-trichloromethyl-2,5-cyclohexadiene-1-one), (3) (4,5-dichloro-1- phenyl-pyridazine-6-one), and (4) ( 2,2,4,5-tetrachloro-cyclopentene-1,3-dione) were studied by single crystal X-ray diffraction and 35Cl nuclear quadrupole resonance (NQR). (1) crystallizes with the space group D152h-Pbca, Z = 8.The lattice constants are a= 1206.0(3) pm, b= 1341.3(3) pm, and c = 1178.8(3) pm. (2) crystallizes monoclinic, space group C52h-P21/c, Z = 4, a = 696.3(3) pm, b = 1404.0(5) pm, c = 1151.4(5) pm, and β = 100.23(1) deg. (3) crystallizes in the orthorhombic space group D42-P212121 , Z = 4, a = 4303(1) pm, b = 586.8(2) pm, and c = 390.5(1) pm. (4) crystallizes cubic, space group T4h-Fd3, with 48 molecules in the unit cell, a = 2181.5(5) pm.The 35Cl NQR spectra were observed for the two 2,5-cyclohexadiene-1-ones, (1) and (2) in the temperature range 77 less equal T/K less melting point.For (3), the 35Cl NQR spectra was determined at T = 77 K and T = 295 K.No phase transition has been found for the three compounds in the temperature range in which the 35Cl NQR spectroscopy was performed.
