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Chemoselective Preparation of 1-Iodoalkynes, 1,2-Diiodoalkenes, and 1,1,2-Triiodoalkenes Based on the Oxidative Iodination of Terminal Alkynes
Published on: September 12, 2018
Surface concentration dependent structures of iodine on Pd(110).
Mats Göthelid1, Michael Tymczenko, Winnie Chow
1Materialfysik, ICT Electrum 229, Kungliga Tekniska Högskolan (KTH), S-164 40 Kista, Sweden. gothelid@kth.se
The Journal of Chemical Physics
|December 5, 2012
Summary
This study reveals how iodine atoms arrange on a palladium surface at different coverages, forming distinct structures with varying electronic properties that influence chemical reactivity.
Area of Science:
- Surface Science
- Materials Chemistry
- Condensed Matter Physics
Background:
- Understanding surface structures is crucial for catalysis and materials science.
- Iodine adsorption on transition metals can significantly alter surface properties.
Purpose of the Study:
- To investigate the coverage-dependent structures of iodine on Palladium(110).
- To analyze the electronic structure differences between various iodine adsorption sites.
- To correlate electronic properties with potential chemical reactivity.
Main Methods:
- Photoelectron spectroscopy
- Low energy electron diffraction (LEED)
- Scanning tunneling microscopy (STM)
- Density functional theory (DFT) calculations
Main Results:
- At 0.5 ML, a c(2x2) structure with iodine in four-fold hollow sites was observed.
- At 2/3 ML, a quasi-hexagonal structure formed with iodine in hollow and long bridge sites.
- Significant electronic structure differences were found between hollow and bridge-bonded iodine, with higher electron density on bridge-bonded iodine.
- Positively charged iodine atoms near vacancies along domain walls were identified.
Conclusions:
- Iodine adsorption on Pd(110) leads to coverage-dependent structural transitions.
- Distinct electronic structures of iodine at different sites suggest varied chemical behavior.
- The presence of charged iodine species and vacancies may influence surface reactions.
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