Bindungscharakteristik der H2-koordinierenden Fragmente W(CO)3(PR3)2. Aussergewöhnliche optische und elektrochemische Eigenschaften zweikerniger Pyrazinkomplexe

Abstract Dinuclear complexes of pyrazine with W(CO) 3 (PR 3 ) 2 , R = isopropyl and cyclohexyl, illustrate a remarkable combination of σ acceptor and π back-donating properties for these fragments. In particular, the complexes exhibit unique absorption spectra with a very intense (e 77000 1 M −1 cm −1 and extremely narrow charge transfer band (band width 850 cm −1 at half height) in the near infrared region. Facile oxidation of the chemically equivalent metal centers occurs in two widely separated (610 mV) reversible steps which set the boundary for the first organometallic analogues of the Creutz-Taube ion.