Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

XXL Cages - Organometallic lattice with unusually large pores can house gases and ferrocene molecules

07.09.2007
It’s full of holes and yet it holds together: Whether as a place to store gas molecules; for the separation of substances; as sensors, catalysts, and nanoreactors; or materials for optoelectronics, porous crystalline solids with a regular array of defined pores have become indispensable in science and technology.

Organometallic compounds can also form porous structures and have greatly broadened the palette of porous materials, though until now these have been limited to species with very small pores. In the journal Angewandte Chemie, Korean researchers led by Jaheon Kim now report the synthesis and characterization of a mesoporous organometallic lattice with cagelike pores that are 3.9 to 4.7 nm in diameter.

Previously, only a few stable structures made of metal atoms or ions and organic ligands have been made that have larger pores, called mesopores (>3 nm in diameter). Among the reasons for this is the special type of bonding that takes place between a metal and a ligand, known as complex coordination. Large cavities can easily destabilize this type of lattice. Just as difficult as the synthesis of such structures is their characterization at the atomic level. The Korean researchers have overcome both challenges. Their lattice structures are made of ions of the rare-earth metal terbium and an organic ligand. By using X-ray crystallographic methods, the scientists were also able to precisely determine the structures of both the crystal and the pores.

The use of nitrogen adsorption measurements also allowed them to confirm that there are two types of pore in the structure, some a little bigger, some smaller. When the samples are activated at 160 °C, the specific surface area of the porous crystals increases further, but its sorption ratio does not change. This behavior is also confirmed in adsorption experiments with carbon dioxide.

... more about:
»ferrocene »lattice »optoelectronic »porous

When irradiated with light, the crystals fluoresce green. They are very thermally stable and hold out well enough in a vacuum to be loaded up by means of a sublimation process with guest molecules that are catalytically active or useful for optoelectronics. The researchers tested this with ferrocene, a molecular “sandwich” with two aromatic five-membered rings acting as the “bread” and an iron atom as the “filling”. With ferrocene guests in its pores, the crystal no longer fluoresces green. Instead, emission from the ferrocene is observed. The researchers believe that the crystal lattice absorbs the photons like an antenna and passes them on to the ferrocene unit in the form of “energy bundles”. The ferrocene molecule in turn gives off this energy in the form of light. However, its emission is stronger than that given off in the irradiation of ferrocene alone. Systems using this construction principle could be useful for future optoelectronic components such as novel light-emitting diodes.

Author: Jaheon Kim, Soongsil University, Seoul (Korea), mailto:jaheon@ssu.ac.kr

Title: Crystal Structure and Guest Uptake of a Mesoporous Metal-Organic Framework Containing Cages of 3.9 and 4.7nm in Diameter

Angewandte Chemie International Edition, doi: 10.1002/anie.200702324

Jaheon Kim | Angewandte Chemie
Further information:
http://pressroom.angewandte.org

Further reports about: ferrocene lattice optoelectronic porous

More articles from Life Sciences:

nachricht 'Y' a protein unicorn might matter in glaucoma
23.10.2017 | Georgia Institute of Technology

nachricht Microfluidics probe 'cholesterol' of the oil industry
23.10.2017 | Rice University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Salmonella as a tumour medication

HZI researchers developed a bacterial strain that can be used in cancer therapy

Salmonellae are dangerous pathogens that enter the body via contaminated food and can cause severe infections. But these bacteria are also known to target...

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

3rd Symposium on Driving Simulation

23.10.2017 | Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

 
Latest News

Microfluidics probe 'cholesterol' of the oil industry

23.10.2017 | Life Sciences

Gamma rays will reach beyond the limits of light

23.10.2017 | Physics and Astronomy

The end of pneumonia? New vaccine offers hope

23.10.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>