Cryptomelane-type manganese oxide shows high efficiency for the NN formation reaction in the oxidative coupling of anilines to azobenzenes. The difference of the Hammett constants (Δσ) of two substituted groups determines the selectivity to unsymmetric azobenzenes in cross-coupling reactions, which are favored at Δσ < 0.32.
Cryptomelane型锰氧化物在苯胺氧化偶联反应中对N-N形成反应表现出高效率。两个取代基的Hammett常数差(Δσ)决定了在交叉偶联反应中对非对称偶氮苯的选择性,当Δσ < 0.32时,会倾向于非对称偶氮苯。