Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Cages Strung Together

09.01.2012
Persilastaffanes: silicon frameworks with delocalized sigma electrons

Persilastaffanes are an unusual new class of compounds that are introduced in the journal Angewandte Chemie by Japanese researchers led by Takeaki Iwamoto at Tohoku University.


They are rod-shaped molecules with a core consisting of one or more tiny “cages” made of silicon atoms. Even more unusual than the name and structure of these materials are the properties of their electrons, which make the materials intriguing candidates as building blocks to make new materials for electronic applications.

Where does the name persilastaffane come from? Persila indicates an organic molecule in which all (“per”) carbon atoms are replaced by silicon atoms (“sila”). A staffane is a special arrangement of five carbon atoms: two “bridgeheads” are bound to each other by way of three “bridges”, each of which has a carbon atom at its center. This results in a cage-like spatial structure. Alternatively, the structure of the cage can be viewed as a wavy ring made of four carbon atoms in which two opposite sides are additionally bridged by another carbon atom. A persilastaffane is a molecule that contains this type of cage made out of silicon atoms.

The Japanese team has developed a synthetic technique to make molecules containing one, two, or three such cages. What is so fascinating about these rod-shaped molecules? To date, there have been few studies of linear chains of silicon-containing ring systems; however theory suggests that there should be significant interactions between the cages. In these cases, the bonding electrons (sigma electrons) in the silicon–silicon bonds should not be localized between the two bonding partners as is usual in chemical bonds; instead, they should be able to move freely (delocalized) over the entire three-dimensional framework of silicon atoms, as in solid silicon.

This property is very interesting because silicon compounds with delocalized sigma electrons absorb light in the UV range, as well as being light-sensitive or conducting. They can also become conducting under light. Iwamoto and his colleagues examined the tiny rods by spectroscopic methods. They were able to confirm considerable delocalization of the sigma electrons over the silicon cages. Iwamoto remarks: “Persilstaffanes are fascinating rod-shaped silicon molecules that could serve as linear connectors for novel silicon-based finely defined materials, such as conductive molecular wires.”

About the Author
Dr Takeaki Iwamoto is Professor of Chemistry at Tohoku University and has been working in the area of organosilicon and main-group-element chemistry for over 15 years.
Author: Takeaki Iwamoto, Tohoku University, Sendai (Japan), http://www.ssoc.chem.tohoku.ac.jp/en_index.html
Title: Persilastaffanes: Design, Synthesis, Structure, and Conjugation between Silicon Cages

Angewandte Chemie International Edition, Permalink to the article: http://dx.doi.org/10.1002/anie.201106422

Dr Takeaki Iwamoto | Angewandte Chemie
Further information:
http://www.ssoc.chem.tohoku.ac.jp/en_index.html
http://pressroom.angewandte.org

More articles from Life Sciences:

nachricht Water forms 'spine of hydration' around DNA, group finds
26.05.2017 | Cornell University

nachricht How herpesviruses win the footrace against the immune system
26.05.2017 | Helmholtz-Zentrum für Infektionsforschung

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Can the immune system be boosted against Staphylococcus aureus by delivery of messenger RNA?

Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.

Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....

Im Focus: A quantum walk of photons

Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.

The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

 
Latest News

How herpesviruses win the footrace against the immune system

26.05.2017 | Life Sciences

Water forms 'spine of hydration' around DNA, group finds

26.05.2017 | Life Sciences

First Juno science results supported by University of Leicester's Jupiter 'forecast'

26.05.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>