From Local Covalent Bonding to Extended Electric Field Interactions in Proton Hydration

Abstract

Seemingly simple yet surprisingly difficult to probe, excess protons in water constitute complex quantum objects with strong interactions with the extended and dynamically changing hydrogen‐bonding network of the liquid. Proton hydration plays pivotal roles in energy transport in hydrogen fuel cells and signal transduction in transmembrane proteins. While geometries and stoichiometry have been widely addressed in both experiment and theory, the electronic structure of these specific hydrated proton complexes has remained elusive. Here we show, layer by layer, how utilizing novel flatjet technology for accurate x‐ray spectroscopic measurements and combining infrared spectral analysis and calculations, we find orbital‐specific markers that distinguish two main electronic‐structure effects: Local orbital interactions determine covalent bonding between the proton and neigbouring water molecules, while orbital‐energy shifts measure the strength of the extended electric field of the proton.

Regioselectivity in the Nitration of Eugenol Is Independent of Inorganic Reagents: An Experimental and Theoretical Investigation with Synthetic and Mechanistic Implications

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Thermally processed Ni-and Co-struvites as functional materials for proton conductivity

“…53,54 Recent O-K-edge XAS results could prove the dominant occurrence of an H 7 O 3 + proton complex in contrast to the conventional explanation of Zundel or Eigen ions, H 5 O 2 + and H 9 O 4 + . 55 In the vehicle mechanism, molecules such as water H 2 O, ammonia NH 3 , or alkali metals Na, K, etc. act as proton acceptors/Brønsted bases and transport the protons as carriers through the compound over large molecular distances.…”

Remediation and recycling of inorganic acids and their green alternatives for sustainable industrial chemical processes

“…The proton mobility has been reported to be an order of magnitude higher than those of other cations in aqueous solution owing to its diffusion via some special transport mechanisms, such as the vehicle mechanism and Grotthuss mechanism. [289][290][291][292] In the vehicle mechanism, the proton moves through the medium as a water cluster by molecular diffusion, while in the Grotthuss mechanism, the protons move from oxygen to oxygen by simultaneously breaking and forming hydrogen bonds. Therefore, in a DD process, a net transport of HX, i.e.…”