CRYSTAL-STRUCTURE AND NQR OF 2 COPPER(I) COMPLEXES OF 4,6-DIMETHYLPYRIMIDINE-2-THIONE

The crystal structure and Cu-63 NQR spectra of two neutral hexanuclear Cu(I) complexes of 4,6-dimethylpyrimidine-2-thione, (Hdmpt); [dmptCu] 6CHCl3 (1) and [dmptCu]6C2H4Cl2(2), are reported. The number and relat ive intensities of the NQR resonances are in agreement with the result s of the crystallographic study. The temperature-dependence of the res onances reveals that both compounds undergo a phase-change in the temp erature range 77 K-300 K, both of which may be associated with the los s of a symmetry-element present in the high-temperature phase. The Cl- 35 resonances of CHCl3 in 1 could be observed in the low-temperature p hase but the corresponding resonances for C2H4Cl2 in 2 were not detect ed.