Biomimetic oxidation of cyclic and linear alkanes: high alcohol selectivity promoted by a novel manganese porphyrin catalystElectronic supplementary information (ESI) available: FTIR and NMR spectra, and tables with the catalytic results. See DOI: 10.1039/c6nj03072f

A novel third-generation metalloporphyrin, chloro-5,10,15,20-tetrakis-(3′-bromine-4′-methoxyphenyl)-2,3,7,8,12,13,17,18-octabromoporphyrinatomanganese( iii ), [Mn III Br 12 T4(-OMe)PPCl], designated as MnBr 12 Por, was synthesized and characterized. The catalytic activity of the new manganese porphyrin was investigated in the oxidation of cyclohexane, adamantane and n -hexane by iodosylbenzene (PhIO) or iodobenzene diacetate (PhI(OAc) 2 ) in comparison to the catalytic activity of the second-generation catalyst [Mn III T4(-OMe)PPCl], designated as MnPor. All yields were based on oxidants. The MnBr 12 Por/PhIO system led to higher yields of cyclohexane oxidation products (45%) with high selectivity for cyclohexanol (80%) as compared to the MnPor/PhIO system (23% and 77%, respectively). Addition of imidazole to MnPor/PhIO increased the total product yield from 23 to 43%; addition of imidazole to MnBr 12 Por/PhIO did not alter the total product yield at all. For the MnPor/PhI(OAc) 2 and MnBr 12 Por/PhI(OAc) 2 systems, addition of imidazole increased the product yields from 19 to 45% and from 35 to 66%, respectively. Addition of water increased the total product yields during cyclohexane and adamantane oxidation for all the studied systems. In all cases, MnBr 12 Por performed better than MnPor. A novel β-brominated Mn-porphyrin acts as a good catalyst for alkane (cyclohexane, adamantine and n -hexane) oxidation in biomimetic systems.