COPPER-63 NUCLEAR-QUADRUPOLE RESONANCE FREQUENCIES AND MOLECULAR GEOMETRIES OF 3-CO-ORDINATE COMPLEXES OF COPPER(I) HALIDES WITH N-ALKYLIMIDAZOLIDINETHIONE AND THIAZOLIDINETHIONE LIGANDS
S. Ramaprabhu et al., COPPER-63 NUCLEAR-QUADRUPOLE RESONANCE FREQUENCIES AND MOLECULAR GEOMETRIES OF 3-CO-ORDINATE COMPLEXES OF COPPER(I) HALIDES WITH N-ALKYLIMIDAZOLIDINETHIONE AND THIAZOLIDINETHIONE LIGANDS, Journal of the Chemical Society. Dalton transactions, (1), 1995, pp. 115-121
The crystal structures of seven three-co-ordinated complexes of copper
(I) halides with thione ligands, [CuXL2], where L = 1,3-thiazolidine-2
-thione and X = Cl or Br, L = N-ethylimidazolidine-2-thione and X = Br
, L = N-isopropylimidazolidine-2-thione and X = Cl or Br, and L = N-pr
opylimidazolidine-2-thione and X = Cl or I have been determined. In al
l complexes, the copper lies in a trigonal-planar environment and the
thiazolidine or imidazolidine rings show no major distortion from plan
arity. Owing to the presence of hydrogen bonding involving H[N(2)], or
H[N(02)], and the halogen atom all complexes adopt a W-shaped conform
ation. The Cu-63 NQR frequencies of these complexes, together with tho
se of two other similar complexes whose structures were already availa
ble, depend, for a given halide, on the S-Cu-S bond angle, a decrease
in angle producing an increase in resonance frequency: V(Cl) = 28.7 -
0.544DELTAGTHETA and V(Br) = 26.9 - 0.229DELTATHETA MHz, where DELTATH
ETA is the difference between the S-Cu-S bond angle and 120-degrees-C.
This behaviour has been rationalized in terms of a partial field-grad
ient model of the resonance frequencies.