Iron(III) meso-tetra(2-carboxyphenyl)porphine chloride (1) was investigated as a soluble electrocatalyst for the oxygen reduction reaction (ORR) in acetonitrile with [H(DMF)(+)]OTf(-). Rotating ring-disk voltammetry, spectroelectrochemistry, and independent reactions with hydrogen peroxide indicate that 1 has very high selectivity for reduction of O(2) to H(2)O, without forming significant amounts of H(2)O(2). Cyclic voltammetric measurements at high substrate/catalyst ratios (high oxygen pressure) allowed the estimation of a turnover frequency (TOF) of 200 s(-1) at -0.4 V vs Cp(2)Fe(+/0). This is, to our knowledge, the first reported TOF for a soluble ORR electrocatalyst under kinetically controlled conditions. The 4-carboxyphenyl isomer of 1, in which the carboxylic acids point away from the iron center, is a much less selective catalyst. This comparison shows that carboxylate groups positioned to act as proton delivery relays can substantially enhance the selectivity of ORR catalysis.

Fe(III)-meso-tetra(pyridyl)porphyrins are electrocatalysts for the reduction of dioxygen in aqueous acidic solution. The 2-pyridyl derivatives, both the triflate and chloride salts, are more selective for the desired 4e(-) reduction than the isomeric 4-pyridyl complexes. The inward-pointing pyridinium groups influence proton delivery despite their distance from the iron centre.

The C-N bond in aromatic N-heterocycles is a strong bond, its cleaving involving mostly examples of metal-element multiple bonds. We report on the C-C coupling of two molecules of an aromatic N-heterocycle mediated by scandium and yttrium benzyl complexes supported by a ferrocene 1,1'-diamide ligand. The reaction with 1-methylimidazole leads, ultimately, to the formation of a ring-opened imidazole coupled to a 1-methylimidazole fragment, a structure showing extended conjugation of double bonds. The experimental evidence agrees with involvement of only sigma bonds in these transformations.

This paper provides an industry perspective on atomic layer etching (ALEt) process. Two process sequences representing two different methods of ALEt are described, followed by several examples where ALEt can be an enabling process technology in the semiconductor industry. The authors believe that there needs to be an increased understanding of surface functionalization, modification and chemistry-based material removal. We are confident that this review article will allow for increased scientific and technological solutions for enabling ALEt.

Synthesis of a scandium dimethylbenzyl complex supported by a ferrocene diamide ligand was accomplished by alkane elimination from Sc(CH 2 Xy-3,5) 3 (THF) 2 . The scandium dimethylbenzyl complex Sc(fc[NSi(t-Bu)Me 2 ] 2 )(CH 2 Xy-3,5)(THF), 2-(CH 2 Xy-3,5)(THF), was used as a starting material for the synthesis of the corresponding chloride-bridged dimer, (2-Cl) 2 , which, in turn, led to a scandium bis(neo-pentyl) ate salt, Li[2-Np 2 ]. Attempts to remove the coordinated THF molecule from 2-(CH 2 Xy-3,5)(THF) with AlMe 3 led to the isolation of a scandium methyl complex with two coordinated AlMe 3 molecules, 2-Me(AlMe 3 ) 2 . Compound 2-Me(AlMe 3 ) 2 led to a scandium methyl complex, 2-Me(THF) 2 , by stirring in THF. All ferrocene diamido compounds were characterized by X-ray crystallography. DFT calculations on model compounds were used to explain the stability of the compounds synthesized and to probe the existence of an iron-scandium interaction. Compounds 2-(CH 2 Xy-3,5)(THF) and 2-Me(AlMe 3 ) 2 polymerize L-lactide.