A new potential toxaphene congener: synthesis, GC/EI-MS study, crystal structure, NMR analysis, and ab initio calculations of 3-endo,5-endo-dichloro-7,7-bis-chloromethyl-4-dichloromethyl-tricyclo[2.2.1.0(2,6)]heptane.

A new potential toxaphene congener 3-endo,5-endo-dichloro-7,7-bis-chloromethyl-4-dichloromethyl-tricyclo[2.2.1.0(2,6)]heptane 2 has been isolated from reaction mixture obtained by the chlorination of 2-exo, 10,10-trichlorobornane 1. The X-ray structural analysis of 2 revealed an unusual tricyclic structure, where the two chlorine atoms occupying endo-positions are in close spatial proximity with each other and near to the neighbouring CHCl2 group. Further, it revealed that the symmetry of the molecule is distorted. The 1H and 13C NMR spectra of 2 have been assigned by means of 1H, 1H double-quantum filtered correlation spectroscopy (DQF COSY), PFG 1H, 13C HMQC (pulsed field gradient heteronuclear multiple-quantum coherence), 1H, 13C heteronuclear multiple bond correlation (HMBC) experiments, and computer aided 1H NMR spectral analysis. The asymmetry of 2 is also discernible on the 1H NMR parameters. In addition, gas chromatographic (GC) properties and electron impact (EI) mass spectrum of 2 has been studied. Ab initio Hartree-Fock (HF) method with the basis set 6-31G(d) has been used for the optimization of the equilibrium geometry and calculation of total energy for 2. The optimized geometry is in good agreement with the crystal structure. According to the rotation energy profile calculated at the HF/6-31G(d) level, rotation of the chloromethyl and dichloromethyl groups are highly unlikely at the room temperature.

Relative retention times of chlorinated monoterpenes.

GC retention times for 67 chlorinated monoterpenes, belonging to the technical pesticide Toxaphene have been measured under the same conditions and relative retention times have been determined. They consisted of 45 chlorinated bornanes, 13 chlorinated bornenes, 8 chlorinated dihydrocamphenes and 1 chlorinated camphene. Useful correlations between structure and retention time were found. Similar changes in structure for different compounds lead to similar changes in retention times. These correlations allow to predict retention times for yet unknown Toxaphene congeners.