Surface-assisted synthesis - a versatile route to novel organic molecules and polymers
Event details
| Date | 09.06.2016 |
| Hour | 16:30 › 17:30 |
| Speaker |
Prof. Michael Gottfried Philipps-Universität Marburg Department of Chemistry, Physical Chemistry |
| Location | |
| Category | Conferences - Seminars |
Surface-assisted synthesis of organic molecules, polymers, metal complexes, and organo-metallic compounds is a promising approach for surface modification and functionalization. Surface reactions can produce compounds which are not accessible by conventional synthesis in solution or which are too large or too reactive for vapor deposition. Catalytic and template effects exerted by the surface can help driving the reaction into the desired direction. The major challenges are structural control and selectivity, because post-reaction separation and purification, which are widely applied in solution-based synthesis, are difficult to perform on surfaces. This lecture focuses primarily on C-C coupling reactions of haloarenes on metal surfaces and their investigation with spectroscopic and microscopic techniques. Temperature-dependent studies show that the carbon-halogen bonds dissociate already at low temperatures and are replaced by carbon-metal-carbon bonds, resulting in the formation of linear, cyclic or two-dimensional organometallic oligomers and polymers. Formation of covalent C-C bonds is achieved at elevated temperatures. The hexagonal, fully conjugated honeycombenes are prominent examples for a class of macrocyclic hydrocarbons for which no solution-based synthesis is available, but which are obtained by on-surface synthesis. As room-temperature stable intermediates, the corresponding organometallic macrocycles are observed. Surface template effects were studied in the synthesis of low-dimensional organic nanostructures on different Cu surfaces, i.e., Cu(111), Cu(110) and Cu(110)-(2x1)O. The latter shows the 'piano keyboard' type pattern consisting of alternating stripes of bundled Cu-O chains and bare Cu(110). Since the reaction proceeds exclusively on the bare Cu stripes, the pattern provides a spatial confinement. Depending on the width of the Cu stripes, either 1D zigzag organometallic oligomeric chains with different lengths or organometallic macrocycles with different sizes are obtained. Finally, examples for structure formation of intact haloarenes are presented.
Practical information
- General public
- Free
Organizer
- Prof. Ulrich Lorenz
Contact
- Prof. Ulrich Lorenz