Bonding character of intermediates in on-surface Ullmann reactions revealed with energy decomposition analysis.

On-surface synthesis has become a thriving topic in surface science. The Ullmann coupling reaction is the most applied synthetic route today, but the nature of the organometallic intermediate is still under discussion. We investigate the bonding nature of prototypical intermediate species (phenyl, naphthyl, anthracenyl, phenanthryl, and triphenylenyl) on the Cu(111) surface with a combination of plane wave and atomic orbital basis set methods using density functional theory calculations with periodic boundary conditions.

The influence of copper on the optical band gap of heterometallic iodido antimonates and bismuthates.

Halogenido metalates of heavy main group elements are versatile semiconductor materials with broad applications. Especially the iodido metalates generally show small optical band gaps, making them suitable for photovoltaics. However, the most promising results have been generated using toxic lead-based materials, raising environmental concerns, while the related and far less toxic bismuth compounds show band gaps too large for direct use in photovoltaics.

Click Chemistry in Ultra-high Vacuum - Tetrazine Coupling with Methyl Enol Ether Covalently Linked to Si(001).

The additive-free tetrazine/enol ether click reaction was performed in ultra-high vacuum (UHV) with an enol ether group covalently linked to a silicon surface: Dimethyl 1,2,4,5-tetrazine-3,6-dicarboxylate molecules were coupled to the enol ether group of a functionalized cyclooctyne which was adsorbed on the silicon (001) surface via the strained triple bond of cyclooctyne. The reaction was observed at a substrate temperature of 380 K by means of X-ray photoelectron spectroscopy (XPS). A moderate energy barrier was deduced for this click reaction in vacuum by means of density functional theory based calculations, in good agreement with the experimental results.

Complementary Base Lowers the Barrier in SuFEx Click Chemistry for Primary Amine Nucleophiles.

The sulfur(VI) fluoride exchange (SuFEx) reaction is an emerging scheme for connecting molecular building blocks. Due to its broad functional group tolerance and rather stable resulting linkage, it is seeing rapid adoption in various fields of chemistry. Still, to date the reaction mechanism is poorly understood, which hampers further development.

Combined XPS and DFT investigation of the adsorption modes of methyl enol ether functionalized cyclooctyne on Si(001).

The reaction of methyl enol ether functionalized cyclooctyne on the silicon (001) surface was investigated by means of X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT). Three different groups of final states were identified; all of them bind on Si(001) via the strained triple bond of cyclooctyne but they differ in the configuration of the methyl enol ether group. The majority of molecules adsorbs without additional reaction of the enol ether group; the relative contribution of this configuration to the total coverage depends on substrate temperature and coverage.

Template-controlled on-surface synthesis of a lanthanide supernaphthalocyanine and its open-chain polycyanine counterpart.

Phthalocyanines possess unique optical and electronic properties and thus are widely used in (opto)electronic devices, coatings, photodynamic therapy, etc. Extension of their π-electron systems could produce molecular materials with red-shifted absorption for a broader range of applications. However, access to expanded phthalocyanine analogues with more than four isoindoline units is challenging due to the limited synthetic possibilities.

Synthesis of a two-dimensional organic-inorganic bismuth iodide metalate through in situ formation of iminium cations.

(Me2C[double bond, length as m-dash]NMe2)Bi2I7 represents a new layered organic-inorganic iodido bismuthate. It displays an unprecedented anion topology, a low band gap and good stability. Advanced electronic structure analysis finds the II interactions to be decisive for the compound's structural and electronic properties.

From Acenaphthenes to (+)-Delavatine A: Visible-Light-Induced Ring Closure of Methyl (α-Naphthyl) Acrylates.

Disclosed herein is a visible light mediated cyclization of methyl (α-naphthyl) acrylates and heteroaromatic analogues yielding substituted acenaphthenes and azaacenaphthenes. This highly functional-group-tolerant transformation was put to the test in an enantioselective formal synthesis of delavatine A. Mechanistic details were elucidated by DFT-calculations revealing an unusual intramolecular H-transfer mediated by a primary amine.

α-Pinene Autoxidation Products May Not Have Extremely Low Saturation Vapor Pressures Despite High O:C Ratios.

COSMO-RS (conductor-like screening model for real solvents) and three different group-contribution methods were used to compute saturation (subcooled) liquid vapor pressures for 16 possible products of ozone-initiated α-pinene autoxidation, with elemental compositions C10H16O4-10 and C20H30O10-12. The saturation vapor pressures predicted by the different methods varied widely. COSMO-RS predicted relatively high saturation vapor pressures values in the range of 10(-6) to 10(-10) bar for the C10H16O4-10 "monomers", and 10(-11) to 10(-16) bar for the C20H30O10-12 "dimers".

The Effect of Water and Bases on the Clustering of a Cyclohexene Autoxidation Product C6H8O7 with Sulfuric Acid.

We investigate the molecular interaction between sulfuric acid and a C6H8O7 ketodiperoxy acid compound (a proxy for highly oxidized products of, e.g., monoterpene autoxidation) in the presence of water, ammonia, or dimethylamine.