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
Angewandte Chemie International Edition, Permalink to the article: http://dx.doi.org/10.1002/anie.201106422
New image of a cancer-related enzyme in action helps explain gene regulation
05.06.2020 | Penn State
Protecting the Neuronal Architecture
05.06.2020 | Universität Heidelberg
Humans rely dominantly on their eyesight. Losing vision means not being able to read, recognize faces or find objects. Macular degeneration is one of the major...
In meningococci, the RNA-binding protein ProQ plays a major role. Together with RNA molecules, it regulates processes that are important for pathogenic properties of the bacteria.
Meningococci are bacteria that can cause life-threatening meningitis and sepsis. These pathogens use a small protein with a large impact: The RNA-binding...
An analysis of more than 200,000 spiral galaxies has revealed unexpected links between spin directions of galaxies, and the structure formed by these links...
Two prominent X-ray emission lines of highly charged iron have puzzled astrophysicists for decades: their measured and calculated brightness ratios always disagree. This hinders good determinations of plasma temperatures and densities. New, careful high-precision measurements, together with top-level calculations now exclude all hitherto proposed explanations for this discrepancy, and thus deepen the problem.
Hot astrophysical plasmas fill the intergalactic space, and brightly shine in stellar coronae, active galactic nuclei, and supernova remnants. They contain...
In living cells, enzymes drive biochemical metabolic processes enabling reactions to take place efficiently. It is this very ability which allows them to be used as catalysts in biotechnology, for example to create chemical products such as pharmaceutics. Researchers now identified an enzyme that, when illuminated with blue light, becomes catalytically active and initiates a reaction that was previously unknown in enzymatics. The study was published in "Nature Communications".
Enzymes: they are the central drivers for biochemical metabolic processes in every living cell, enabling reactions to take place efficiently. It is this very...
19.05.2020 | Event News
07.04.2020 | Event News
06.04.2020 | Event News
05.06.2020 | Life Sciences
05.06.2020 | Physics and Astronomy
05.06.2020 | Life Sciences