63Cu High Resolution NMR of Cu(I) Halides in Aqueous Solution and Suspension

Article abstract of DOI:10.1246/bcsj.60.2803

In an aqueous solution, 63Cu chemical shielding order (^3- ca. ^3- < ^3-) and line widths (10 to 30 kHz) for CuX-KX systems (where X=Cl,Br,I) have been obtained.The chemical shift (-694 ppm) between ^3- and ^3- is interpreted by the paramagnetic term which depends mainly upon a 3d-hole on a Cu(I) atom by using perturbation theory with an average excitation energy approximation.The line-broadening of Cu(I) halide complexes in aqueous solution is explained dominantly by a Cu(I) nuclear quadrupole interaction with the electric field gradient which arises from a 3d-hole on a Cu atom.For the abnormal increasing metal shielding order of ^(4-i)-(^{(4-i)- (4-i)-} < ^(4-i)-), a possibility of the heavy-atom effect in the metal shielding of ^3- (649 ppm, using the lowest excitation energy of the diatomic molecule) and ^3- (1941 ppm using the lowest excitation energy of the diatomic molecule), is evaluated.