A cathodic reduction potential shift of L substituted derivatives vs the parent clusters showed that coordination of L to Co resulted in the increase of charge density on CCo_3 unit, wkioh made the cluster hard to reduce.

• 取代簇合物的还原电势相对于母体簇合物的负移表明P的配位增大了CCo_3上的电荷密度,导致簇合物难被还原。