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The activation of the [2,6-bis(1-((2,6-diisopropylphenyl)imino)ethyl)pyridine]iron(II) chloride complex (1) with methylaluminoxane (MAO) was investigated in tetrahydrofuran (THF) by means of electrospray ionization tandem mass spectrometry (ESI-MS) complemented by UVvisible spectroscopy studies. The four-coordinated cationic methyl iron(II) complex 2 ([LFe-Me] + , L ) 2,6-bis(1-((2,6-diisopropylphenyl)imino)ethyl)pyridine) was identified in the ESI-MS experiment. In addition, the cationic monochloride iron(II) complex 3 ([LFe-Cl] + ), the product of R-H transfer from 2 to trimethylaluminum (TMA) [LFe-CH 2 AlMe 2 ] + (4), and the cationic iron hydride complex 5 ([LFe-H] + ) were identified. Correlation of the ESI-MS experiments with UV-visible studies revealed that 2 and 3 are present in the THF solution as their solvent adducts.

A simple and efficient parallel screening method to evaluate the catalytic activities of homogeneous copper complexes for the oxidation of benzylic alcohols in aqueous solutions with molecular oxygen is reported. Copper(II) sulfate was treated in situ with 22 nitrogen donor ligands, and the catalytic activities of these combinations were studied at four different pH values with two substrates (benzyl alcohol and 3,4-dimethoxy benzyl alcohol (veratryl alcohol)), resulting in 176 oxidation experiments in the primary screening stage. Copper complexes based on N,N,N',N'-tetramethyl ethylenediamine (TMEDA), 9,10-diaminephenanthrene (DAPHEN), and 1,2-diaminocyclohexane (DACH) were determined to be the most active catalysts. In the second screenings, the influence of reaction conditions on Cu(DACH)-, Cu(TMEDA)-, and Cu(DAPHEN)-catalyzed reactions were investigated in more detail. It was found that highly basic reaction conditions favor the reaction with the exception of Cu(TMEDA), which is active at a lower pH range. Under optimized conditions, Cu(DAPHEN) catalyzes the transformation of veratryl alcohol to the corresponding aldehyde with 100% conversion.