Featured Research

from universities, journals, and other organizations

Blue-fluorescent molecular nanocapsules created by simple mixing 'green-environmentally friendly' metal ions and bent organic blocks

Date:
July 12, 2012
Source:
Tokyo Institute of Technology
Summary:
New fluorescent molecular nanocapsules have potential applications as sensors, displays, and drug delivery systems (DDS).

Fluorescent properties of the copper capsule.
Credit: Tokyo Institute of Technology

New fluorescent molecular nanocapsules have potential applications as sensors, displays, and drug delivery systems (DDS).

Michito Yoshizawa, Zhiou Li, and collaborators at Tokyo Institute of Technology (Tokyo Tech) synthesized ~1 nanometer-sized molecular capsules with an isolated cavity using green and inexpensive zinc and copper ions. In sharp contrast to previous molecular capsules and cages composed of precious metal ions such as palladium and platinum, these nanocapsules emit blue fluorescence with 80% efficiency.

Molecular nanocapsules have potential applications as photo-functional compounds and materials but so far molecular capsules synthesized by incorporating palladium ions and so on exhibit poor fluorescence.

The Tokyo Tech researchers expect to be able to prepare multicolor fluorescence composites by the simple insertion of appropriate fluorescent molecules into the isolated cavity of the nanocapsules.

Fluorescence has widespread applications, helping researchers to understand issues in the fundamental sciences and develop practical materials and devices. Among the useful fluorescent compounds in development, capsule-shaped molecular architectures, which possess both strong fluorescent properties and a nanometer-sized cavity, are particularly promising.

Molecular cages and capsules can be prepared through a simple synthetic process called coordinative self-assembly. However, most of them are composed of precious metal ions such as palladium and platinum, and are non-emissive due to quenching by the heavy metals.

Now, Michito Yoshizawa, Zhiou Li, and co-workers from the Chemical Resources Laboratory at Tokyo Institute of Technology report novel molecular nanocapsules with the M2L4 composition (where M represents zinc, copper, platinum, palladium, nickel, cobalt, and manganese). Their zinc and copper capsules, in particular, display unique fluorescent properties.

The M2L4 capsules self-assemble from two metal ions and four bent ligands that include anthracene fluorophores (fluorescent parts). X-ray crystallographic analysis verified the closed shell structures where the large interior cavities of the capsules, around one nanometer in diameter, are shielded by eight anthracene panels.

The zinc capsule emitted strong blue fluorescence with a high quantum yield (80%), in sharp contrast to the weakly emissive nickel and manganese capsules and the non-emissive palladium, platinum, and cobalt capsules. The fluorescence of the copper capsule, on the other hand, depends on the solvent; for example, it shows blue emission in dimethyl sulfoxide but no emission in acetonitrile.

This study is the first to show such emissive properties of molecular capsules bearing an isolated large cavity. The researchers believe their nanocapsules could have novel applications in devices such as chemosensors, biological probes, and light-emitting diodes.


Story Source:

The above story is based on materials provided by Tokyo Institute of Technology. Note: Materials may be edited for content and length.


Journal Reference:

  1. Zhiou Li, Norifumi Kishi, Kenji Yoza, Munetaka Akita, Michito Yoshizawa. Isostructural M2L4 Molecular Capsules with Anthracene Shells: Synthesis, Crystal Structures, and Fluorescent Properties. Chemistry - A European Journal, 2012; 18 (27): 8358 DOI: 10.1002/chem.201200155

Cite This Page:

Tokyo Institute of Technology. "Blue-fluorescent molecular nanocapsules created by simple mixing 'green-environmentally friendly' metal ions and bent organic blocks." ScienceDaily. ScienceDaily, 12 July 2012. <www.sciencedaily.com/releases/2012/07/120712111634.htm>.
Tokyo Institute of Technology. (2012, July 12). Blue-fluorescent molecular nanocapsules created by simple mixing 'green-environmentally friendly' metal ions and bent organic blocks. ScienceDaily. Retrieved July 28, 2014 from www.sciencedaily.com/releases/2012/07/120712111634.htm
Tokyo Institute of Technology. "Blue-fluorescent molecular nanocapsules created by simple mixing 'green-environmentally friendly' metal ions and bent organic blocks." ScienceDaily. www.sciencedaily.com/releases/2012/07/120712111634.htm (accessed July 28, 2014).

Share This




More Matter & Energy News

Monday, July 28, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Lithium Battery 'Holy Grail' Could Provide 4 Times The Power

Lithium Battery 'Holy Grail' Could Provide 4 Times The Power

Newsy (July 28, 2014) Stanford University published its findings for a "pure" lithium ion battery that could have our everyday devices and electric cars running longer. Video provided by Newsy
Powered by NewsLook.com
The Carbon Trap: US Exports Global Warming

The Carbon Trap: US Exports Global Warming

AP (July 28, 2014) AP Investigation: As the Obama administration weans the country off dirty fuels, energy companies are ramping-up overseas coal exports at a heavy price. (July 28) Video provided by AP
Powered by NewsLook.com
Shipping Crates Get New 'lease' On Life

Shipping Crates Get New 'lease' On Life

Reuters - Business Video Online (July 25, 2014) Shipping containers have been piling up as America imports more than it exports. Some university students in Washington D.C. are set to get a first-hand lesson in recycling. Their housing is being built using refashioned shipping containers. Lily Jamali reports. Video provided by Reuters
Powered by NewsLook.com
Europe's Highest Train Turns 80 in French Pyrenees

Europe's Highest Train Turns 80 in French Pyrenees

AFP (July 25, 2014) Europe's highest train, the little train of Artouste in the French Pyrenees, celebrates its 80th birthday. Duration: 01:05 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins