35Cl NQR of dimethyl tetrachloroterephthalate

The title compound exhibits four 35Cl NQR lines. The NQR frequencies have been measured as a function of temperature between 77 and 425 K. Four lines exhibit normal negative temperature dependence. At 77 K the spectrum composed of the lines at 37.462, 37.521, 37.570, and 37.783 MHZ is different from that reported previously. The Zeeman effect on 35C1 NQR in a single crystal has been studied at room temperature. It is deduced on the basis of the orientations of the efg axes that there are two crystallographically nonequivalent molecules in the crystal. The angles between the adjacent C-CI bonds are estimated to be 62.99±0.05°in one of these molecules and 61.77±0.05°in another.