NMR investigation of spin transfer to H in K2CuCl4∙2H2O

Abstract

Nuclear magnetic resonance of 1H in K2CuCl4∙2H2O has been measured with frequencies of 3 to 35 MHz at room temperature, 163, and 77 K. The fractional spin transfer from the copper ion to hydrogen due to the transferred hyperfine interaction is analyzed: 0.19 ± 0.03% at 300 K, 0.23 ± 0.02% at 163 K, and 0.27 ± 0.02% at 77 K, showing that the spin transfer is temperature dependent. This temperature dependence is closely associated with the unusually strong temperature dependent super-exchange interaction between Cu2+ ions in this crystal.