The synthesis of binuclear iron and chromium complexes with bridging dppe ligands is reported, e.g. [μ-dppe{C5H5Fe(CO)Br}2] or [μ-dppe{C5H5Cr(CO)(NO)}2], (dppe = (C6H5)2PC2H4P(C6H5)2). With hydrazine, these compounds yield no doubly bridged complexes with dppe and N2H4 bridges, neither in dark- nor in photo-reactions. In case of the iron complexes either reduction of the starting complex or transformation of the dppe bridging ligand into a chelating ligand are observed instead. The reactions

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... end upon the polarity of the solvent and yield [μ-dppe{C5H5Fe(CO)}2] in benzene, however, [C5H5Fe(CO)(dppe)]Br in tetrahydrofuran. The chromium complex undergoes decomposition on UV irradiation, splitting off CO and yielding the chelate complex [C5H5Cr(NO)(dppe)] as well as polymeric [C5H5Cr(NO)]x.