Zusammenfassung
The first paramagnetic Cu(I) dimers [L2Cu(m-L1)CuL2]+.bul. (L = PPh3, L2 = Ph2PCH2CH2PPh2, 1,5-cyclooctadiene) were obtained as stable species from the reactions of Cu(I) reagents with electron-deficient binucleating ligands L1 = 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine (I) and 4,7-phenanthroline-5,6-dione (II) under reducing conditions. ESR spectroscopy reveals that the unpaired electron resides mainly in the p* orbital of the bridging ligand L1 whereas a small amt. of spin d. is hyperconjugatively transferred to the L2Cu(I) fragments. Complexes of I may be regarded as models for the metal-to-ligand charge-transfer excited state in (a-diimine)/Cu(I) species whereas the a-amino-o-quinone ligand II can serve as model for the dehydrogenase and amine oxidase cofactor methoxatin. [on SciFinder(R)]
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