A UV-vis study of the effects of alcohols on formation and stability of Mn(por)(O)(OAc) complexes

作者：Mohajer Daryoush^*; Jahanbani Maryam

来源：Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy , 2012, 91: 360-364.

DOI：10.1016/j.saa.2012.01.001

• Manganese porphyrin
• UV-vis
• Alcohols
• O ligand

Interactions of three different (acetato) (tetraarylporphyrinato) manganese (III) Mn-III(por) with tetra-n-butylammonium hydrogen monopersulfate (n-Bu4NHSO5), in the presence of excess tetra-n-butylammonium acetate (n-Bu4NOAc) and in the absence or presence of various alcohols (alcohols =CH3OH, C2H5OH, i-C3H7OH, t-C4H9OH) in CH2Cl2, were monitored by their UV-vis spectral changes, under identical conditions, at room temperature. (Acetato) (tetrakispentafluorophenylporphyrinato) manganese (III) Mn-III(tpfpp)(OAc) and (acetato) (tetramesitylporphyrinato) manganese (III) Mn-III(tmp)(OAc) produced their corresponding high valent Mn(tpfpp)(O)(OAc) and Mn(tmp)(O)(OAc) both in the absence or presence of alcohols. Whereas, (acetato) (tetraphenylporphyrinato) manganese (III) Mn-III(tpp)(OAc) only generated Mn(tpp)(O)(OAc) in the presence of less bulky alcohols. In the absence of alcohols or in the presence of t-C4H9OH, the UV-vis spectra displayed a very weak sign of formation of Mn(tpp)(O)(OAc) complex. It was observed that alcohols generally increased the rate of formation of Mn-oxo species in accordance with their acidity or hydrogen bonding strength, and enhanced the stability of Mn-oxo complexes, as their size increases. Attempts are made to explain these effects. A mechanistic scheme is also suggested for the decomposition of HSO5- to O-2 and HSO4-, through the formation and dimerization of Mn-oxo species.

• 出版日期2012-6