Homogeneous and heterogeneous olefin epoxidation catalyzed by a binuclear Mn(II)Mn(III) complex

Crystal structure of aqua-chlorido-(nitrato-κ2O,O')[1-(pyridin-2-yl-κN)-2-(pyridin-2-yl-methyl-idene-κN)hydrazine-κN2]manganase(II)

The search for novel manganese(II) compounds having inter-esting magnetic properties, using 1-(pyridin-2-yl)-2-(pyridin-2-yl-methyl-idene)hydrazine (HL) as a tridendate ligand, led to the preparation of the title mononuclear material, [MnCl(NO3)(C11H10N4)(H2O)], and the determination of its structure by XRD. The asymmetric unit comprises a discrete mol-ecule in which the cation MnII is hepta-coordinated. The environment around the cation is an almost perfect penta-gonal bipyramid. The base is defined by the two N atoms of the pyridine rings, the N atom of the imino function of the ligand and the two O atoms of the chelating bidentate nitrate ligand. The apical positions are occupied by a Cl atom and a water mol-ecule. In the crystal, there are numerous hydrogen bonds of the types Ow-H⋯ONO2 and C-H⋯ONO2, which generate layers parallel to the bc plane in which the ligands in the axial positions point into the inter-layer space. These axial ligands give rise to hydrogen bonds of the types Ow-H⋯ONO2, Ow-H⋯Cl, N-H⋯Cl and C-H⋯Cl, leading to a three-dimensional framework. The chain bridging the two pyridine rings is disordered over two sets of sites in a 0.53 (2):0.47 (2) ratio.

Crystal structure of bis-(μ-4-nitro-benzoato-κ2O:O')bis-[bis-(4-methyl-pyridine-κN)(4-nitro-benzoato-κ2O,O')manganese(II)]

The title compound, [Mn2(C7H4NO4)4(C6H7N)4] or [Mn2(μ-NBz)2(κ2-NBz)2(4-Mepy)4], where NBz is 4-nitro-benzoate and 4-Mepy is 4-methyl-pyridine, is a centrosymmetric dinuclear complex in which the MnII atoms are bridged by two NBz ligands with Mn⋯Mn = 4.1324 (4) Å. The MnII atom in this dimeric species is present in a distorted octa-hedral environment with the four coordinating O atoms forming the equatorial plane and the two pyridyl N atoms occupying the axial sites. An important structural feature of the dimeric complex is that each of the bridging carboxyl-ate ligands binds to the metal ions in an asymmetric fashion involving bent and linear Mn-O-C units. The crystal packing is consolidated by C-H⋯O and C-H⋯π interactions.

Halogenated tetraphenyl porphyrin; iodosylbenzene an efficient catalytic system for olefin epoxidation

Olefin epoxidation using o-phenyl and [Formula: see text]-pyrrole substituted tetraphenyl porphyrin complexes of Fe(III) and Mn(III) as catalysts and [Formula: see text]Iodosylbenzene as oxidant was studied. Excellent yields of epoxide and secondary oxidation products were observed. Effect of pyridine, imadizole, sodium lauryl sulphate, and solvent variation was also studied. Effect of substituents on catalytic activity of the porphyrin complex is also explained. o-phenyl substituted complexes gave better yield of epoxide as compared to [Formula: see text]-pyrrole substituted complexes.

Oxidation mechanism of molecular oxygen over cyclohexene catalyzed by a cobalt l-glutamic acid complex

We introduce a new strategy towards the cyclohexene oxidation reaction, which is driven by molecular oxygen with a cobalt(ii)/amine acid complex as the catalyst without any solvents.