Octahedrally coordinated cobalt(II) complexes with ar edox-active bisguanidine ligand and acac co-ligands were synthesized and their redoxc hemistry analysed in detail. The N À Hfunctions in abisguanidine ligand with partially alkylated guanidino groups form N À H•••O hydrogen bonds with the acac co-ligands,t hereby massively influencing the redox chemistry. Fora ll complexes,t he first one-electron oxidation is metalcentred, leading to Co III complexes with neutral bisguanidine ligand units.Further one-electron oxidation is ligand-centred in the case of Co-bisguanidine complexes with fully alkylated guanidino groups,g iving Co III complexes with radical monocationic bisguanidine ligands.O nt he other hand, the hydrogen-bond strengthening upon oxidation of the Co-bisguanidine complex with partially alkylated guanidino groups initiates metal reduction (Co III !Co II )and two-electron oxidation of the guanidine ligand, providing the first example for the stimulation of redox-induced electron transfer by interligand hydrogen bonding.

The authors present a new method to determine film thicknesses and sticking coefficients (SC) of precursor molecules for atomic layer deposition (ALD) in high aspect ratio three dimensional (3D) geometries as they appear in microelectromechanical system manufacturing. The method combines a specifically designed experimental test structure with the theoretical predictions from a novel 3D Monte Carlo process simulation for large structures. The authors exemplify our method using Al2O3 and SiO2 ALD processes. SCs for trimethylaluminium and bis-diethyl aminosilane (BDEAS) are extracted. The SC for BDEAS is determined for the first time.

Herein, we report the first examples of the use of redox-active guanidines as catalysts in the green oxidation of organic molecules with dioxygen. In one half-reaction, the oxidized form of the redox-active guanidine is converted into the reduced, protonated state, thereby enabling dehydrogenative oxidation of the substrate (3,5-di-tert-butylcatechol→ortho-benzoquinone, benzoin→benzil, and 2,4-di-tert-butylphenol→biphenol). In the other half-reaction, efficient re-oxidation of the guanidine to the oxidized state is achieved with dioxygen in the presence of a copper catalyst. These results pave the way for the broader use of redox-active guanidines as oxidation catalysts.

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In this paper, the authors present the temperature dependent sticking coefficient (SC) of bis-diethyl aminosilane (BDEAS) and trimethylaluminum (TMA) in atomic layer deposition. SiO2 from BDEAS and ozone at substrate temperatures between 200 and 350 °C as well as Al2O3 from TMA and water deposited at substrate temperatures between 150 and 300 °C was deposited on our likewise in this journal published cavity test structures. The SC of BDEAS shows an Arrhenius dependence while for TMA no temperature dependent SC could be resolved. The activation energy for BDEAS which is extracted from a linear fit to the Arrhenius diagram is compared to the value gained by density functional theory calculations from the literature. Furthermore, the different growth behavior of BDEAS and TMA under substrate temperature considerations is identified with different deposition regimes as proposed in the literature.