OXIDATION OF NO2(-) BY [MN-2(IV)(MU-O)(2)(MU-OAC)(H2O)(2)(BIPY)(2)](3- A PROBABLE EXAMPLE OF A 2-ELECTRON TRANSFER-REACTION() ION )

The title complex 1 coexists in equilibrium with [Mn-2(IV) (mu-O)(2)(H 2O)(4)(bipy)(2)](4+) (2) and [Mn-2(IV) (mu-O)(2)(mu-OAc)(H2O)(4)(bipy) ](3+) (3) in mixed (OAc- + bipy) aqueous buffer. The complexes are qua ntitatively reduced to Mn-II by NO2-, which is itself oxidised to NO3- . There is no kinetic and UV-vis spectral evidence for any intermediat e Mn-III.IV complex, and the reactions appear to be two-electron trans fer processes. The rate of reduction increases with increasing extent of hydrolysis in the sequence 1 < 2 < 3. A plausible interpretation ha s been presented. (C) 1997 Elsevier Science Ltd.