Reduction-Oxidation Properties of Organotransition-metal Complexes. Part 26. The Synthesis of Paramagnetic Triazenido- and Aryl(1-aryliminoethyl)amido-bridged Dirhodium Carbonyl Derivatives containing the 3+ Core

Article abstract of DOI:10.1039/DT9870001403

Cyclic voltammetry shows that <1, L' = RNNNR, R = p-tolyl; 2, L' = R'NC(Me)NR', R' = Ph>, (3, L = PPh3 or CNBu^t), 2> (4, L = CO), 4-diene)2(μ-RNNNR)2> <5, diene = nbd (norborna-2,5-diene) or cod (cylo-octa-1,5-diene)>, and t)(μ-RNNNR)2> (6) undergo at least two diffusion-controlled one-electron oxidations at a platinum bead electrode in CH2Cl2.The first process is reversible for all of the complexes and corresponds to the formation of a monocation with a ³⁺ core.The second step is fully reversible only for (1), (3, L = PPh3), and (5, diene = nbd), and for the first two of these complexes a third reversible oxidation wave is also observed.The paramagnetic monocations (3⁺, L = PPh3 or CNBu^t), (4⁺, L = CO), and (5⁺, diene = nbd) have been isolated as stable hexafluorophosphate salts via the oxidation of the appropriate neutral complex with either or in CH2Cl2.The related complex (7⁺, dppm = Ph2PCH2PPh2) was also prepared, by the oxidation of a mixture of (1) and dppm.The tricarbonyl (4⁺, L = CO) undergoes substitution with Lewis bases, L, to give the cationic dicarbonyls <4⁺, L = PPh3, AsPh3, or P(OPh)3> which are readily reduced by n4> in CH2Cl2 to give the otherwise inaccesible neutral species <4, L = PPh3, AsPh3, or P(OPh)3>.

Full text of DOI:10.1039/DT9870001403

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