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In early seventies ligand-bridged ruthenium ammine
complexes [(NH3)5Ru-L-Ru(NH3)5](4+,5+,6+) have been prepared
with L=pyrazine,4,4''-bipyridine,and 4,4''-bipyridine derivation
derivatives .Many of there compounds Ru(II)-L-Ru(III)belong
to class II of the Robin-Day classification,ie,the oxidation
states ofthe two metallic centers are still welll defined and
only a weak coupling betw-een ruthenium centers is observed.
Interest in long-range electron transfer through bipyridine
system ofthis type Ru(II)-L-Ru(III) where L=1,2-bis(4-
pyridyl)ethane or (E,E)-1,4-Bis(4-pyridyl)-1,3-bytadiene or (E,
E,E)-1,6-Bis(4-pyridyl)-1,3,5-hexatriene or (E,E,E,E)-1,8-Bis(4-
pyridyl)-1,3,5,7-octatetraene has been hammered by the
extremelyweak intervalence bands.In search of a system with
decent electronic interacti-on between the two ruthenium centers
, the follwing ligand Di(2PyFc),Di(3PyFc),Di(4PyFc) where
prepared and characterized.
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