Ligand effects on coordination properties of organolithium compounds: insights from computational experiments on a “weakened” Li+

The reaction of organolithium compounds with 1-substituted 2,4,6-triphenylpyridinium perchlorates Ia-Ic produces mixtures of 1,4-dihydropyridines IIa-IIe and 1,2-dihydropyridines IIIa-IIIe. Analogous reactions of phenylmagnesium bromide with compounds Ia-Ic proceed with very low conversions (less than 1%). Photochromism in visible range is observed only with the compounds II which have two aromatic substituents at 4-position, whereas compounds III and IId show no visible photochromism. The molecular spectra of the compounds newly prepared are discussed.

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Cover Feature: Precursor Nuclearity and Ligand Effects in Atomically‐Dispersed Heterogeneous Iron Catalysts for Alkyne Semi‐Hydrogenation (ChemCatChem 14/2021)

ChemCatChem ◽

10.1002/cctc.202100888 ◽

2021 ◽

Vol 13 (14) ◽

pp. 3199-3199

Author(s):

Dario Faust Akl ◽

Andrea Ruiz‐Ferrando ◽

Edvin Fako ◽

Roland Hauert ◽

Olga Safonova ◽

...

Keyword(s):

Iron Catalysts ◽

Ligand Effects

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A Comparative Study of Oxygen and Hydrogen Adsorption on Strained and Alloy-Supported Pt(111) Monolayers

Magnetochemistry ◽

10.3390/magnetochemistry7070101 ◽

2021 ◽

Vol 7 (7) ◽

pp. 101

Author(s):

Ian Shuttleworth

Keyword(s):

Comparative Study ◽

Density Functional ◽

Hydrogen Adsorption ◽

Binding Energies ◽

High Symmetry ◽

Density Functionals ◽

Functional Theory ◽

Ligand Effects ◽

Ferromagnetic Alloys ◽

Depth Study

A comparative study of the unreacted and reacted uniaxially strained Pt(111) and the layered (111)-Pt/Ni/Pt3Ni and (111)-Pt/Ni/PtNi3 surfaces has been performed using density functional theory (DFT). An in-depth study of the unreacted surfaces has been performed to evaluate the importance of geometric, magnetic and ligand effects in determining the reactivity of these different Pt surfaces. An analysis of the binding energies of oxygen and hydrogen over the high-symmetry binding positions of all surfaces has been performed. The study has shown that O and H tend to bind more strongly to the (111)-Pt/Ni/Pt3Ni surface and less strongly to the (111)-Pt/Ni/PtNi3 surface compared to binding on the equivalently strained Pt(111) surfaces. Changes in the surface magnetisation of the surfaces overlaying the ferromagnetic alloys during adsorption are discussed, as well as the behaviour of the d-band centre across all surfaces, to evaluate the potential mechanisms for these differences in binding. An accompanying comparison of the accessible density functionals has been included to estimate the error in the computational binding energies.

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