Nanotechnology Now

Our NanoNews Digest Sponsors
Heifer International



Home > Press > Chromium-Centered Cycloparaphenylene Rings as New Tools for Making Functionalized Nanocarbons

One-pot selective monofunctionalization of CPP via a chromium complex
One-pot selective monofunctionalization of CPP via a chromium complex

Abstract:
Professor Kenichiro Itami, Yasutomo Segawa and Natsumi Kubota of the JST-ERATO Itami Molecular Nanocarbon Project and the Institute of Transformative Bio-Molecules (ITbM), Nagoya University have synthesized novel cycloparaphenylene (CPP) chromium complexes and demonstrated their utility in obtaining monofunctionalized CPPs, which could become useful precursors for making carbon nanotubes with unprecedented structures. CPPs consist of a chain of benzene rings and are the shortest segment of carbon nanotubes. Since their first synthesis and isolation in 2008, CPPs have attracted wide attention in the fields of materials science and supramolecular chemistry. Applying the basic concepts of chromium arene chemistry, Itami and his coworkers have performed the first selective installation of a functional group on CPP, which has previously been difficult due to multiple reactive arene sites on the CPP ring. By being able to selectively install and tune the functional groups on CPPs, it is envisaged that carbon nanotubes with new properties can be constructed by this method. The study, published online on January 12, 2015 in the Journal of the American Chemical Society, illustrates the first synthesis, isolation and analysis of a CPP chromium complex, which enables a one-pot access to monofunctionalized CPPs. This outcome is believed to be a significant advance in the fields of both CPP chemistry and organometallic chemistry.

Chromium-Centered Cycloparaphenylene Rings as New Tools for Making Functionalized Nanocarbons

Nagoya, Japan | Posted on February 24th, 2015

Arenes are known to coordinate to transition metals and the corresponding metal complexes exhibit different reactivities relative to the free arene. CPPs, which consist of a chain of arenes, also reacted with chromium carbonyl to successfully generate the first chromium complex of CPP. Interestingly, the main product was a CPP with one chromium moiety complexed to one arene on the outer side of the ring, as confirmed by 1H NMR (nuclear magnetic resonance) spectroscopy, high-resolution mass spectrometry and X-ray crystallography.

"Chromium arene chemistry is a well-established area and we decided to apply this organometallic method to synthesize the first CPP chromium complex," says Itami, the Director of the JST-ERATO project and the Institute of Transformative Bio-Molecules. "As CPPs have a number of arene rings, we initially expected that chromium would form a complex with each arene ring," says Segawa, a group leader of the JST-ERATO project. "However, we were surprised to see that CPP reacted with chromium in a 1:1 ratio in all the conditions that we tried. Simulation of the molecular structure suggested that the first equivalent of chromium complexed to CPP lowers its reactivity, thus preventing the reaction with a second chromium moiety."

Upon finding that a monometallic CPP complex could be obtained, Itami's team explored the possibility of obtaining monofunctionalized CPPs from this complex. Itami and Segawa describe the steps in achieving this. "This was not an easy task as chromium arene complexes are usually air and light sensitive, and CPP chromium complexes were no exception. But Natsumi worked persistently to obtain a pure crystal of the first CPP chromium complex," says Itami. "We then performed the subsequent reactions in one-pot, to synthesize monofunctionalized CPPs after addition of base/electrophiles and removal of the metal from the CPP chromium complex," says Segawa.

Selective monofunctionalizations of CPPs i.e. installation of one functional group at a single position on the arene ring, are difficult to achieve as all carbon-hydrogen bonds on the arene rings are chemically equivalent. Direct functionalization of metal-free CPPs usually leads to multiple substitutions on the arene rings in an uncontrolled manner. Despite CPPs being desirable components for carbon nanotubes, there has been no efficient method to obtain directly functionalized CPPs up to now.

"We were pleased to see that a functional group could be selectively installed on one arene ring via chromium coordination of CPPs," says Segawa. "As electrophiles, we utilized silyl, boryl and ester groups, which act as handles that can be easily transformed to other useful functionalities," he continues. Itami says, "We hope that this new approach evolves to become a valuable method to construct carbon nanotubes with unique structures and properties."

####

About ITbM, Nagoya University
The World Premier International Research Center Initiative (WPI) for the Institute of Transformative Bio-Molecules (ITbM) at Nagoya University in Japan is committed to advance the integration of synthetic chemistry, plant/animal biology and theoretical science, all of which are traditionally strong fields in the university. As part of the Japanese science ministry’s MEXT program, ITbM aims to develop transformative bio-molecules, innovative functional molecules capable of bringing about fundamental change to biological science and technology. Research at ITbM is carried out in a “Mix-Lab” style, where international young researchers from multidisciplinary fields work together side-by-side in the same lab. Through these endeavors, ITbM will create “transformative bio-molecules” that will dramatically change the way of research in chemistry, biology and other related fields to solve urgent problems, such as environmental issues, food production and medical technology that have a significant impact on the society.

About JST-ERATO Itami Molecular Nanocarbon Project (www.jst.go.jp/erato/itami/index.html)

This project entails the design and synthesis of as-yet largely unexplored nanocarbons as structurally well-defined molecules, and the development of novel, highly functional materials based on these nanocarbons. Through the combination of chemical and physical methods, the project aims to achieve the controlled synthesis of well-defined uniquely structured nanocarbon materials. Interdisciplinary research is conducted to encompass the control of molecular arrangement and orientation, structural and functional analysis, and applications in devices and biology.

About JST-ERATO (www.jst.go.jp/erato/en/about/index.html)

ERATO (The Exploratory Research for Advanced Technology), one of the Strategic Basic Research Program, aims to form a headstream of science and technology, and ultimately contribute to science, technology, and innovation that will change society and the economy in the future. In ERATO, a Research Director, a principal investigator of ERATO research project, establishes a new research base in Japan and recruits young researchers to implement his or her challenging research project within a limited time frame.

For more information, please click here

Contacts:
Professor Kenichiro Itami
Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University
Furo-Cho, Chikusa-ku, Nagoya 464-8601, Japan
TEL/FAX: +81-52-788-6098


Media Contact
Dr. Ayako Miyazaki
Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University
Furo-Cho, Chikusa-ku, Nagoya 464-8601, Japan
TEL: +81-52-789-4999 FAX: +81-52-789-3240

Copyright © ITbM, Nagoya University

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related Links

Full bibliographic information

Related News Press

Chemistry

What heat can tell us about battery chemistry: using the Peltier effect to study lithium-ion cells March 8th, 2024

Two-dimensional bimetallic selenium-containing metal-organic frameworks and their calcinated derivatives as electrocatalysts for overall water splitting March 8th, 2024

News and information

Researchers develop artificial building blocks of life March 8th, 2024

How surface roughness influences the adhesion of soft materials: Research team discovers universal mechanism that leads to adhesion hysteresis in soft materials March 8th, 2024

Two-dimensional bimetallic selenium-containing metal-organic frameworks and their calcinated derivatives as electrocatalysts for overall water splitting March 8th, 2024

Nanotubes/Buckyballs/Fullerenes/Nanorods/Nanostrings

Catalytic combo converts CO2 to solid carbon nanofibers: Tandem electrocatalytic-thermocatalytic conversion could help offset emissions of potent greenhouse gas by locking carbon away in a useful material January 12th, 2024

TU Delft researchers discover new ultra strong material for microchip sensors: A material that doesn't just rival the strength of diamonds and graphene, but boasts a yield strength 10 times greater than Kevlar, renowned for its use in bulletproof vests November 3rd, 2023

Tests find no free-standing nanotubes released from tire tread wear September 8th, 2023

Detection of bacteria and viruses with fluorescent nanotubes July 21st, 2023

Discoveries

What heat can tell us about battery chemistry: using the Peltier effect to study lithium-ion cells March 8th, 2024

Researchers’ approach may protect quantum computers from attacks March 8th, 2024

High-tech 'paint' could spare patients repeated surgeries March 8th, 2024

Nanoscale CL thermometry with lanthanide-doped heavy-metal oxide in TEM March 8th, 2024

Announcements

What heat can tell us about battery chemistry: using the Peltier effect to study lithium-ion cells March 8th, 2024

Curcumin nanoemulsion is tested for treatment of intestinal inflammation: A formulation developed by Brazilian researchers proved effective in tests involving mice March 8th, 2024

The Access to Advanced Health Institute receives up to $12.7 million to develop novel nanoalum adjuvant formulation for better protection against tuberculosis and pandemic influenza March 8th, 2024

Nanoscale CL thermometry with lanthanide-doped heavy-metal oxide in TEM March 8th, 2024

Interviews/Book Reviews/Essays/Reports/Podcasts/Journals/White papers/Posters

Researchers develop artificial building blocks of life March 8th, 2024

How surface roughness influences the adhesion of soft materials: Research team discovers universal mechanism that leads to adhesion hysteresis in soft materials March 8th, 2024

Curcumin nanoemulsion is tested for treatment of intestinal inflammation: A formulation developed by Brazilian researchers proved effective in tests involving mice March 8th, 2024

Nanoscale CL thermometry with lanthanide-doped heavy-metal oxide in TEM March 8th, 2024

NanoNews-Digest
The latest news from around the world, FREE




  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project