ABSTRACT
X band studies of alkyl/alkloxy phenyl substituted Cu complexes indicate that only C8O-Cu exhibits a complex hyperfine structure (h. f. s.) at 300K. It also undergoes a first-order phase transition around 213K. However, the complex h. f. s. could not be delineated at X band. In the Q band, in addition to the four permitted h. f. lines, 10 forbidden lines due to quadrupole effects are observed. Further, the forbidden lines disappear in the discophase but the permitted h. f. lines remain. This difference between C8O-Cu and C8Cu could be explained from their crystal structures. In C8O-Cu, the repeating unit is a Cu dimer, as opposed to a single Cu atom placed at the inversion centre in CnCu. Distortion in the dimer, possibly accounts for the observed quadrupole effects.