Dye synthesis in nothing but water instead of toxic solvents – researchers at TU Wien develop a highly efficient and environmentally friendly synthesis for organic pigments.
Perylene bisimides are a heavily investigated and sought after class of organic pigments, since they show interesting dye properties. While these compounds are red pigments in the solid state, when dissolved, they generate bright yellowish-green solutions under UV irradiation. Aside their optical appeal; organic molecules that appear colored in daylight often also show intriguing electronic properties. Therefore, organic dyes are promising lightweight materials for application as e.g. organic semiconductors, but also in for instance LCD displays or solar cells.
Rethinking a complex chemical synthesis
The laboratory of Dr. Miriam M. Unterlass at the Institute of Materials Chemistry at TU Wien has just reported the synthesis of more than 20 different perylene bisimide dyes. This is not impressive per se. The way they prepare these compounds is though: Conventionally, perylene bisimides are generated in highly toxic solvents and employing toxic and expensive catalysts. Moreover, classical reactions towards these dyes require an important excess of the starting compounds. Finally, tedious purification is necessary for obtaining dye products of sufficient purity. All in all, the conventional route is a complex chemical synthesis. “In our approach, we are using the starting compounds in a 1:1 ratio, i.e. without an excess of reactants. The starting compounds are dispersed in water inside a closed reactor. Then the mixture is heated to 200?C and increased pressure is generated”, explains Dr. Unterlass. “In fact, the reactor basically works like a pressure cooker.” Such reactions in hot water under pressure are called hydrothermal syntheses. After the reaction has completed, the final perylene bisimide dyes are obtained with high purity, thus removing the necessity for tedious purification. For actual electronic applications, perylene bisimdes are mostly implemented by device engineers and physicists, who often do not have access to chemical laboratories. The novel hydrothermal synthesis bears the potential of enabling an easy access to these materials – an important step towards realistic application.
From big molecules to small molecules
Previously, Miriam Unterlass’ team had developed a novel process for high-performance polymers, which equally takes place in hot water. The hydrothermal synthesis of perylene bisimide dyes now shows for the first time that small molecules can also be generated “in the pressure cooker”. The order of developments is rather untypical. Normally, novel synthetic pathways are first developed for small molecules – which are often easier to conceive – and later transposed to polymers, i.e. “big molecules”. Despite their small size, the hydrothermal synthesis was however very challenging. For perylene bisimides. They are very apolar, which means that they do not like water – at room temperature. By heating the water to increased temperatures, this challenge can however be met. The hydrothermal synthesis of perylene bisimides is highly efficient and environmentally friendly, and has just been published in the journal Chemical Communications.
Learn more: Fluorescence Dyes from the Pressure Cooker
Receive an email update when we add a new FLOURESCENCE DYES article.
The Latest on: Organic fluorescence dyes
via Google News
The Latest on: Organic fluorescence dyes
- Organic nanotubes could change the delivery of targeted cancer treatments on November 5, 2019 at 10:18 am
Nanotubes synthesized from organic molecules could provide a new method for the precise ... “By precisely engineering these nanotubes with fluorescent dyes and cancer-targeting molecules, scientists ...
- PV against cancer on October 27, 2019 at 5:00 pm
Research from the United States has demonstrated how PV technology can be used to kill cancer cells. Although still at an embryonic stage, the findings of the study and initial test results suggest ...
- Scientists say solar technology may detect, attack cancer cells on October 27, 2019 at 8:32 am
Prior to the Lunts’ combined effort, fluorescent dyes used for therapeutics and diagnostics, aka “theranostics,” had shortcomings, such as low brightness, high toxicity to cells, poor tissue ...
- Modulating cellular cytotoxicity and phototoxicity of fluorescent organic salts through counterion pairing on October 25, 2019 at 2:23 am
However, current fluorescent dyes are limited by low brightness ... control of the optical properties from the electronic properties of fluorescent organic salts. This is achieved through cation-anion ...
- Long‐term thermal stability of fluorescent dye used for chiral amino acid analysis on future spaceflight missions on October 20, 2019 at 5:00 pm
Abstract Future spaceflight missions focused on life detection will carry with them new, state‐of‐the‐art instrumentation capable of highly selective and sensitive organic analysis ... stability of ...
- Water Tracing Dyes Suppliers on October 17, 2019 at 5:00 pm
Manufacturer of water tracing and UltraViolet(UV) leak detection dyes. Organic Dyes and Pigments offers water tracing ... ORCOACID® RHODAMINE WT LIQUID is a fluorescent red tracer dye to detect water ...
- Fluorescent slab detects liquid level on September 30, 2019 at 5:00 pm
As fluid level rises, light escapes the slab at a higher point, reducing fluorescence (right). In this case, the test fluid is water. Click here to enlarge image Made of methyl styrene doped with an ...
- Petroleum and Fuel Dyes and Markers Market based on geographical scope, Revenue Models and financial performance end 2027 on September 13, 2019 at 8:47 am
The global petroleum and fuel dyes and markers market is segmented by type:-fluorescent dyes, azo dyes ... request-1027 Petroleum and fuel dyes and markers are synthetic or organic, unsaturated ...
- One-atom switch supercharges fluorescent dyes: Rice University lab discovers simple technique to make biocompatible 'turn-on' dyes on September 12, 2019 at 5:00 pm
With one-step organic synthesis, they replaced an oxygen atom in the ... "We demonstrated in the paper that it works the same for a range of fluorescent dyes. Basically, one reaction solves a lot of ...
via Bing News