Metal-to-bridge charge transfer bands

As was noted earlier, the dominant mode of electronic coupling for dicarboxylate bridged compounds involves the it orbitals of the bridge and the MM8 orbitals. Thus complexes of this type show intense MLCT bands that typically fall in the visible region of the spectrum. Once again the oxalate bridged series of complexes 

Since the electronic coupling between the M2 centers is dependent upon the conjugation within the bridge this may be modulated by both steric and electronic 

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