Solvation of Co(II) in Methanol and Water Enriched in Oxygenhyphen;17

摘要

The solvation sphere of cobaltous ion in oxygenhyphen;17hyphen;enriched methanol and water solutions was observed by oxygenhyphen;17 magnetic resonance. The chemical shift between the coordinated methanol molecules and the bulk methanol and the transverse relaxation times of oxygenhyphen;17 in the two environments were measured in the temperature range of minus;27.5deg; to plus;21deg;C. The hyperfine coupling constant between the cobaltous ion unpaired electrons and the oxygenhyphen;17 nuclei was found to be temperature independent and its value minus;(1.70thinsp;plusmn;thinsp;0.03)thinsp;times;thinsp;107Hz. The relaxation time of the unpaired electrons of the cobaltous ion was calculated and found to be 7thinsp;times;thinsp;10minus;13sec at 25deg;C, assumingT1ethinsp;equals;thinsp;T2e. The dipolar contribution to the relaxation rate of the oxygenhyphen;17 was calculated and found to be about 1percnt; of the hyperfine contribution. The oxygenhyphen;17 chemical shift between the coordinate water molecules and the noncoordinated water molecules and their transverse relaxation times were measured at temperatures of minus;15deg;, minus;10deg;, and minus;5deg;C. The hyperfine coupling constant and the unpaired electron relaxation time were found to beAthinsp;sol;thinsp;hthinsp;equals;thinsp;minus;thinsp;lpar;1.74thinsp;plusmn;thinsp;0.03rpar;thinsp;times;thinsp;107Hzandtgr;ethinsp;equals;thinsp;1.7thinsp;times;thinsp;10minus;12secat minus;10deg;C assumingT1ethinsp;equals;thinsp;T2e.