Tag Archives: J. Fraser Stoddart

RIP (rest in peace) Sir Fraser Stoddart, nanotechnology pioneer

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I received (via email and it’s also here) a January 2, 2025 Northwestern University news release by Megan Fellman announcing Sir Fraser Stoddart’s (also known as, J. Fraser Stoddart) death on December 30, 2024, Note: Links have been removed,

Sir Fraser Stoddart, a pioneer in nanoscience, dies at 82

Stoddart received the 2016 Nobel Prize in Chemistry for work on molecular machines

EVANSTON, Ill. — Nobel laureate Sir Fraser Stoddart, a Board of Trustees Professor at Northwestern University, died Dec. 30 [2024]. He was 82.

Stoddart, a pioneer in the fields of nanoscience and organic chemistry, was an outsized figure on the Evanston campus and on campuses he visited around the globe. By introducing an additional type of bond — the mechanical bond — into chemical compounds, Stoddart became one of the
few chemists to have opened a new field of chemistry during the past 30 years.

His work on molecular recognition and self-assembly and his subsequent introduction of template-directed routes to mechanically interlocked molecules dramatically changed the way chemists make soft materials.

Throughout his long career of research and teaching, Stoddart mentored a diverse group of more than 500 graduate and postdoctoral students from around the world. Gregarious and thoughtful, he particularly cherished this work and the resulting relationships, many of them lifelong.

“Fraser was a giant in fields of nanoscience and organic chemistry, but his influence was equally impressive in the classrooms and labs on our campus,” said Northwestern President Michael Schill. “He was incredibly generous with his time and mentored so many students and
faculty, helping pave important new paths of inquiry and discovery. His impact on our university — and the world — was enormous.”

Omar Faha, the Charles E. and Emma H. Morrison Professor in Chemistry at Northwestern and chair of the department, said beyond his scientific brilliance, Stoddart was a steadfast friend and mentor, always generous with his time, wisdom and encouragement. “His contributions to our community went far beyond his accolades, as he supported and elevated each of us through his boundless energy and spirit.”

Since 2023, Stoddart was the Chair Professor of Chemistry at the University of Hong Kong.

A Northwestern Nobel

Stoddart received the Nobel Prize in Chemistry in 2016, along with Jean-Pierre Sauvage and Bernard L. Feringa, “for the design and synthesis of molecular machines.” The Royal Swedish Academy of Sciences credited them with developing “molecules with controllable movements, which can perform a task when energy is added.”

“The development of computing demonstrates how the miniaturization of technology can lead to a revolution,” the academy said in its announcement. “The 2016 Nobel Laureates in Chemistry have miniaturized machines and taken chemistry to a new dimension.”

For his part, Stoddart was awarded the prize because, the academy said, in 1991 he developed a rotaxane. He threaded a molecular ring onto a thin molecular axle and demonstrated that the ring was able to move along the axle. Among his developments based on rotaxanes are a molecular lift, a molecular muscle and a molecule-based computer chip.

Stoddart’s introduction of the mechanical bond, which has led to the fabrication of artificial molecular switches and motors, has been responsible for putting chemists at the forefront of the burgeoning field of molecular nanotechnology, with implications ranging all the way from information technology to health care.

Upon becoming the second Nobel Prize winner from Northwestern’s department of chemistry, Stoddart expressed his appreciation for the University’s academic community.

“I also share this recognition with my students, postdoctoral fellows and colleagues,” he said. “Northwestern is a special place, where everyone does science in a collaborative way. It happens seamlessly here. If you don’t have the expertise, you can find it, and people step forward without being asked. It is well known that we hunt in packs at Northwestern.”

Said Adrian Randolph, dean of the Weinberg College of Arts and Sciences at Northwestern: “Sir Fraser brought a sparkling creativity, an indefatigable work ethic, a global perspective and a sharp wit that often reflected his broad interests and his belief in the value of a liberal arts education to his work and life. His scientific findings and ambition will continue to reverberate through the College and University. He will be sorely missed.”

Scientific achievements

Stoddart’s achievements include raising the bar for molecular electronics. For example, he used molecules on the nanoscale as the tiniest of switches, which have been incorporated into the densest of memory chips in a device that can hold the Declaration of Independence but is only the size of a white blood cell. He also gave practical expression to artificial molecular switches using nanovalves planted on the surfaces of mesoporous glass nanoparticles to create controllable and targeted drug delivery systems for the treatment of cancer and other degenerative diseases.

In 2007, The Sunday Times in the U.K. wrote that Stoddart “is to nanotechnology what J.K. Rowling is to children’s literature.”

That same year, he was appointed by Her Majesty Queen Elizabeth II as a Knight Bachelor in her 2007 New Year’s Honours List for his services to “Chemistry and Molecular Nanotechnology.”

“After being knighted, the queen and I had a short exchange, and I concluded she had her wits about her and had done her homework,” Stoddart recalled in a 2022 interview with Northwestern Now after the Queen’s passing. He was one of three to receive knighthoods at a ceremony that included other significant honors. “The main subject of conversation among us afterwards was, ‘How did she know so much about me?’”

A native of Edinburgh, Scotland, Stoddart also received the Royal Medal in 2010 from His Royal Highness the Duke of Edinburgh at the Royal Society of Edinburgh (RSE), Scotland’s national academy of arts and sciences.

A common theme of Stoddart’s research was the quest for a better fundamental understanding of self-assembly and molecular recognition processes in chemical systems. He worked for more than three decades on using this growing understanding to develop template-directed protocols that rely upon such processes to create artificial molecular machines. Stoddart’s philosophy of transferring concepts from biology into chemistry was behind his bottom-up approach to the construction of integrated nanosystems.

“My research on mechanically interlocked molecules, which has taken the field of supramolecular chemistry, i.e., chemistry beyond the molecule, back into the molecular domain, heralds a game-changer for molecular nanotechnology,” Stoddart once said.

Northwestern nanoscientist Chad Mirkin said hiring Stoddart was one of the best moves the University made.

“He is a big part of the ‘rise of Northwestern’ story,” said Mirkin, the George B. Rathmann Professor of Chemistry and a professor of medicine, chemical and biological engineering, biomedical engineering, and materials science and engineering. “Generous with his time, intellect and support, he made Northwestern and everyone around him better.”

Other honors and activities

Stoddart was elected to Fellowship of the American Academy of Arts and Sciences in 2012, membership of the National Academy of Sciences in 2014, foreign membership of the Chinese Academy of Sciences in 2017 and Fellowship of the National Academy of Inventors in 2019.

During his career, Stoddart received many other prestigious national and international awards and honors. They include being elected an Honorary Fellow of both the RSE and the Royal Society of Chemistry (RSC) and receiving the Davy Medal from the Royal Society of London, the national
academy of science of the United Kingdom and the Commonwealth, of which he was also a Fellow. Other awards include the China International Science and Technology Cooperation Award, the Nagoya Gold Medal in Organic Chemistry, the American Chemical Society’s Arthur C. Cope Award, the Feynman Prize in Nanotechnology, the King Faisal International Prize in Science, the Tetrahedron Prize for Creativity in Organic Chemistry, the Albert Einstein World Award of Science and the RSC’s Centenary Prize.

Stoddart served on the international advisory boards of numerous journals, including Chemistry World, Organic Letters and ChemPlusChem. He published more than 1,300 scientific papers and trained more than 500 graduate and postdoctoral students during an academic career that spanned five decades.

Northwestern professor Will Dichtel was one of Stoddart’s postdoctoral researchers.

“Underlying his considerable accolades was an endlessly supportive and caring mentor, colleague and friend. I was fortunate to learn from him first as a postdoctoral researcher at UCLA, just before he moved to Northwestern, where he encouraged my creativity and courage to tackle big scientific problems,” said Dichtel, the Robert L. Letsinger Professor of Chemistry.

“Later, in my independent career, he continued to support, encourage and challenge me. Fraser played this role to hundreds of scientists around the world. We will all miss him dearly and take this sad occasion to reflect upon and acknowledge his considerable personal and scientific
impact.”

Prior to Northwestern

Before joining the Northwestern faculty, Stoddart was Fred Kavli Chair in Nanosystems Sciences at the University of California at Los Angeles and director of the California NanoSystems Institute. He came to UCLA in 1997 from England’s University of Birmingham, where he had been a professor of organic chemistry since 1990 and had headed the university’s School of Chemistry since 1993.

Born in Edinburgh in 1942, Stoddart received his Bachelor of Science (1964), Ph.D. (1966) and D.Sc. (1980) degrees from the University of Edinburgh.

In 1967, he moved to Queen’s University in Ontario, Canada, where he was a National Research Council postdoctoral fellow and then, in 1970, to England’s University of Sheffield, where he was first an Imperial Chemical Industries (ICI) research fellow before becoming a faculty lecturer (assistant professor) in chemistry. After spending a three-year “secondment” (1978 to 1981) at the ICI Corporate Laboratory in Runcorn, England, he returned full time to the University of Sheffield,
where he was promoted to a readership (associate professorship). He moved to the University of Birmingham in 1990 to take up the Chair of Organic Chemistry.

Survivors include his two daughters, Fiona McCubbin of Belmont, Massachusetts, and Alison Stoddart of Cambridge, UK, and five grandchildren. His wife, Norma, preceded him in death.

I have an October 6, 2016 post for when the 2016 Nobel Prize in Chemistry was announced but I find a February 19, 2018 posting “2016 Nobel prize winner introduces anti-aging skincare line” about Stoddart’s then latest venture more intriguing.

2016 Nobel prize winner introduces anti-aging skincare line

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When last mentioned here (Oct. 6, 2016 posting), J. Fraser Stoddart, along with his French colleague Jean-Pierre Sauvage and his Dutch colleague Bernard “Ben” Feringa, had just been awarded a 2016 Nobel Prize for Chemistry for developing molecular machines. In what seems like an unusual career move, Stoddart has recently introduced a skin care line. From a December 5, 2017 article by Marc S. Reisch for Chemical and Engineering News (c&en), Note: A link has been removed,

In 2016, J. Fraser Stoddart won the Nobel Prize in Chemistry for his part in designing a molecular machine. Now as chief technology officer and co-founder of nanotechnology firm PanaceaNano, he has introduced the “Noble” line of antiaging cosmetics including a $524 formula described as an “anti-wrinkle repair” night cream. The firm says the cream contains patented Nobel Prize-winning “organic nano-cubes” loaded with ingredients that reverse skin damage and reduce the appearance of wrinkles.

Other prize-winning chemists have founded companies, but Stoddart’s backing of the anti-aging cosmetic line takes the promotion of a new company by an award-winning scientist to the next level.

The nano-cubes are made of carbohydrate molecules known as cyclodextrins. The cubes, of various sizes and shapes, release ingredients such as vitamins and peptides onto the skin “at predefined times with molecular precision,” according to the Noble skin care website. PanaceaNano co-founder Youssry Botros, former nanotechnology research director at Intel, contends that the metering technology makes the product line “far superior to comparable products in the market today,” However, the nanocubes aren’t molecular machines, for which Stoddart won his Nobel prize.

A November 27, 2017 PanaceaNano news release on Cision PR Newswire provides more details about the skin care line,

The NOBLE skin care breakthrough technology is based on patented Organic Nano-Cube (ONC) molecules, which are made up of hollow cubes that work as molecular reservoirs to store and release skin care active ingredients in an extended release formulation directly onto the skin in a controlled manner, allowing for continuous skin revitalization, renewal and repair over a longer period of time.

Unlike other products, with ONC, you have more than just extended release. ONC molecules provide tunable release profiles that are engineered for delayed and multiple release of different ingredients that each have their own characteristics. ONC molecules are controllable at a smaller nano-scale to better control the individual molecular ingredients. NOBLE is “Skin Care with Molecular Precision” because ONC molecules really control the release of active skin care ingredients at the molecular level, instead of just putting the ingredients in a macroscopic slow-release matrix like other products in the market today.

“This molecular precision enables the NOBLE luxury skin care product line to reduce visible signs of aging more effectively by precisely releasing the anti-aging ingredients for over a longer period. Because of the revolutionary ONC technology, NOBLE has a much longer duration of anti-aging benefit with continuous and steady efficacy, making it far superior to comparable products in the market today,” says Dr. Youssry Botros, PanaceaNano Co-founder and CEO. “Other skin care brands have immediate release formulations whose active ingredients are often depleted immediately. NOBLE products are clinically proven to reverse and slow down skin aging.”

NOBLE skin care products will immediately start working on the skin. Most consumers notice relatively visible results within two weeks, while significant results are observed by most consumers after 10 to 12 weeks.

“It is an exciting moment to witness the birth of commercial products that improve the quality of life of people based on renewable, safe, organic, bio-degradable functional nanomaterials,” stated Sir Fraser.

For additional information, please go to www.noble-skincare.com

Noble/Nobel? Was someone indulging in word play?

According to the Noble skin care product page, costs range from $249. for .5 oz of anti-aging eye cream to $524 for 1.7 oz of anti-wrinkle repair cream, presumably in US dollars. Note: I am not endorsing this product as I have not used it.

For anyone interested in the parent company, PanaceaNano can be found here.

2016 Nobel Chemistry Prize for molecular machines

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Wednesday, Oct. 5, 2016 was the day three scientists received the Nobel Prize in Chemistry for their work on molecular machines, according to an Oct. 5, 2016 news item on phys.org,

Three scientists won the Nobel Prize in chemistry on Wednesday [Oct. 5, 2016] for developing the world’s smallest machines, 1,000 times thinner than a human hair but with the potential to revolutionize computer and energy systems.

Frenchman Jean-Pierre Sauvage, Scottish-born Fraser Stoddart and Dutch scientist Bernard “Ben” Feringa share the 8 million kronor ($930,000) prize for the “design and synthesis of molecular machines,” the Royal Swedish Academy of Sciences said.

Machines at the molecular level have taken chemistry to a new dimension and “will most likely be used in the development of things such as new materials, sensors and energy storage systems,” the academy said.

Practical applications are still far away—the academy said molecular motors are at the same stage that electrical motors were in the first half of the 19th century—but the potential is huge.

Dexter Johnson in an Oct. 5, 2016 posting on his Nanoclast blog (on the IEEE [Institute of Electrical and Electronics Engineers] website) provides some insight into the matter (Note: A link has been removed),

In what seems to have come both as a shock to some of the recipients and a confirmation to all those who envision molecular nanotechnology as the true future of nanotechnology, Bernard Feringa, Jean-Pierre Sauvage, and Sir J. Fraser Stoddart have been awarded the 2016 Nobel Prize in Chemistry for their development of molecular machines.

The Nobel Prize was awarded to all three of the scientists based on their complementary work over nearly three decades. First, in 1983, Sauvage (currently at Strasbourg University in France) was able to link two ring-shaped molecules to form a chain. Then, eight years later, Stoddart, a professor at Northwestern University in Evanston, Ill., demonstrated that a molecular ring could turn on a thin molecular axle. Then, eight years after that, Feringa, a professor at the University of Groningen, in the Netherlands, built on Stoddardt’s work and fabricated a molecular rotor blade that could spin continually in the same direction.

…

Speaking of the Nobel committee’s selection, Donna Nelson, a chemist and president of the American Chemical Society told Scientific American: “I think this topic is going to be fabulous for science. When the Nobel Prize is given, it inspires a lot of interest in the topic by other researchers. It will also increase funding.” Nelson added that this line of research will be fascinating for kids. “They can visualize it, and imagine a nanocar. This comes at a great time, when we need to inspire the next generation of scientists.”

The Economist, which appears to be previewing an article about the 2016 Nobel prizes ahead of the print version, has this to say in its Oct. 8, 2016 article,

BIGGER is not always better. Anyone who doubts that has only to look at the explosion of computing power which has marked the past half-century. This was made possible by continual shrinkage of the components computers are made from. That success has, in turn, inspired a search for other areas where shrinkage might also yield dividends.

One such, which has been poised delicately between hype and hope since the 1990s, is nanotechnology. What people mean by this term has varied over the years—to the extent that cynics might be forgiven for wondering if it is more than just a fancy rebranding of the word “chemistry”—but nanotechnology did originally have a fairly clear definition. It was the idea that machines with moving parts could be made on a molecular scale. And in recognition of this goal Sweden’s Royal Academy of Science this week decided to award this year’s Nobel prize for chemistry to three researchers, Jean-Pierre Sauvage, Sir Fraser Stoddart and Bernard Feringa, who have never lost sight of nanotechnology’s original objective.

…

…

Optimists talk of manufacturing molecule-sized machines ranging from drug-delivery devices to miniature computers. Pessimists recall that nanotechnology is a field that has been puffed up repeatedly by both researchers and investors, only to deflate in the face of practical difficulties.

There is, though, reason to hope it will work in the end. This is because, as is often the case with human inventions, Mother Nature has got there first. One way to think of living cells is as assemblies of nanotechnological machines. For example, the enzyme that produces adenosine triphosphate (ATP)—a molecule used in almost all living cells to fuel biochemical reactions—includes a spinning molecular machine rather like Dr Feringa’s invention. This works well. The ATP generators in a human body turn out so much of the stuff that over the course of a day they create almost a body-weight’s-worth of it. Do something equivalent commercially, and the hype around nanotechnology might prove itself justified.

Congratulations to the three winners!

Toggling atomic switches and other talks at the Foresight Institute’s 2013 technical conference

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The correct title for the conference, which took place almost one year ago (Jan. 11-13, 2013 in Palo Alto, California, US, is the 2013 Foresight Technical Conference: Illuminating Atomic Precision, and the organizers, the Foresight Institute in a Dec. 2, 2013 posting by James Lewis have announced a number of conference videos have been made available and have provided a transcript of sorts for one of the videos,

A select set of videos from the 2013 Foresight Technical Conference: Illuminating Atomic Precision, held January 11-13, 2013 in Palo Alto, have been made available on vimeo. Videos have been posted of those presentations for which the speakers have consented. Other presentations contained confidential information and will not be posted.

Here’s a listing of the 2013 conference presentations made available (click to access the videos),

  • Larry Millstein: Introductory comments at Foresight Technical Conference 2013
  • J. Fraser Stoddart: Introductory comments at Foresight Technical Conference 2013
  • Leonhard Grill: “Assembly and Manipulation of Molecules at the Atomic Scale”
  • John Randall: “Atomically Precise Manufacturing”
  • Philip Moriarty: “Mechanical Atom Manipulation: Towards a Matter Compiler?”
  • David Soloveichik: “DNA Displacement Cascades”
  • Alex Wissner-Gross: “Bringing Computational Programmability to Nanostructured Surfaces”
  • Joseph Puglisi: “Deciphering the Molecular Choreography of Translation”
  • Feynman Awards Banquet at Foresight Technical Conference 2013
  • Gerhard Klimeck: “Multi-Million Atom Simulations for Single Atom Transistor Structures”
  • William Goddard: “Nanoscale Materials, Devices, and Processing Predicted from First Principals” [Note: He’s a wearing a jaunty beret adding a note of style not usually found at technical conferences.]
  • Gerhard Klimeck: “Mythbusting Knowledge Transfer Mechanisms through Science Gateways”
  • Art Olson: “New Methods of Exploring, Analyzing, and Predicting Molecular Interactions”
  • George Church: “Regenesis: Bionano”
  • Dean Astumian: “Microscopic Reversibility: The Organizing Principle for Molecular Machines”
  • Larry Millstein: Closing comments at Foresight Technical Conference 2013

In his Foresight Institute blog posting  Lewis goes on to offer a description of Philip Moriarty’s presentation “Mechanical Atom Manipulation: Towards a Matter Compiler?,”

Prof. Moriarty presented his work with the qPlus technique of non-contact AFM of semiconductors, using chemical forces to mechanically move atoms around to structure matter, focusing on the tip of the probe—specifically how to optimize the tip structure, and how to return the tip to a previously known state. He begins with a brief review of how non-contact AFM uses a damped, driven oscillator to measure and manipulate what is happening at the level of single chemical bonds. The tip at the end of the oscillating cantilever measures the frequency shift of the cantilever as it approaches and interacts with the surface, and it maintains a constant amplitude of oscillation by pumping energy into the system. The frequency shift provides information about conservative forces acting on the tip, and the amount of energy pumped in gives a handle on non-conservative, or dissipative, forces. Before diving into the experimental details of his own work, Prof. Moriarty noted that various experimental accomplishments have vindicated Eric Drexler’s assertion that single atom chemistry could be done using purely mechanical force.

…

I found this description to be a beautiful piece of technical writing although I do have to admit to being distracted by thoughts of Sherlock Holmes on reading “Prof. Moriarty.” One final note, I noted the reference to Eric Drexler in the last sentence of my excerpt as Drexler was a Foresight Institute founder amongst his many other accomplishments.

When mining for gold nanoparticles use substitute cornstarch for cyanide

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A May 14, 2013 news release from Northwestern University (US) on EurekAlert notes that researchers have found cornstarch can be used in the place of cyanide to extract gold,

Northwestern University scientists have struck gold in the laboratory. They have discovered an inexpensive and environmentally benign method that uses simple cornstarch — instead of cyanide — to isolate gold from raw materials in a selective manner.

This green method extracts gold from crude sources and leaves behind other metals that are often found mixed together with the crude gold. The new process also can be used to extract gold from consumer electronic waste.

Commonly used techniques, according to the news release, are problematic,

Current methods for gold recovery involve the use of highly poisonous cyanides, often leading to contamination of the environment. Nearly all gold-mining companies use this toxic gold leaching process to sequester the precious metal.

“The elimination of cyanide from the gold industry is of the utmost importance environmentally,” said Sir Fraser Stoddart, the Board of Trustees Professor of Chemistry in the Weinberg College of Arts and Sciences. “We have replaced nasty reagents with a cheap, biologically friendly material derived from starch.”

Here’s how the researchers made their accidental discovery (from the news release),

Zhichang Liu, a postdoctoral fellow in Stoddart’s lab and first author of the paper, took two test tubes containing aqueous solutions — one of the starch-derived alpha-cyclodextrin, the other of a dissolved gold (Au) salt (called aurate) — and mixed them together in a beaker at room temperature.

Liu was trying to make an extended, three-dimensional cubic structure, which could be used to store gases and small molecules. Unexpectedly, he obtained needles, which formed rapidly upon mixing the two solutions.

“Initially, I was disappointed when my experiment didn’t produce cubes, but when I saw the needles, I got excited,” Liu said. “I wanted to learn more about the composition of these needles.”

…  said Stoddart, a senior author of the paper[,] “The needles, composed of straw-like bundles of supramolecular wires, emerged from the mixed solutions in less than a minute.”

After discovering the needles, Liu screened six different complexes — cyclodextrins composed of rings of six (alpha), seven (beta) and eight (gamma) glucose units, each combined with aqueous solutions of potassium tetrabromoaurate (KAuBr4) or potassium tetrachloroaurate (KAuCl4).

He found that it was alpha-cyclodextrin, a cyclic starch fragment composed of six glucose units, that isolates gold best of all.

“Alpha-cyclodextrin is the gold medal winner,” Stoddart said. “Zhichang stumbled on a piece of magic for isolating gold from anything in a green way.”

Alkali metal salt waste from this new method is relatively environmentally benign, Stoddart said, while waste from conventional methods includes toxic cyanide salts and gases. The Northwestern procedure is also more efficient than current commercial processes.

The supramolecular nanowires, each 1.3 nanometers in diameter, assemble spontaneously in a straw-like manner. In each wire, the gold ion is held together in the middle of four bromine atoms, while the potassium ion is surrounded by six water molecules; these ions are sandwiched in an alternating fashion by alpha-cyclodextrin rings. Around 4,000 wires are bundled parallel to each other and form individual needles that are visible under an electron microscope.

“There is a lot of chemistry packed into these nanowires,” Stoddart said. “The elegance of the composition of single nanowires was revealed by atomic force microscopy, which throws light on the stacking of the individual donut-shaped alpha-cyclodextrin rings.”

The atomic detail of the single supramolecular wires and their relative disposition within the needles was uncovered by single crystal X-ray crystallography.

As I’ve noted before, the perennial science story is a ‘mistake’ leading to an exciting discovery and this is one more example. I think it’s one of the things that scientists don’t get enough credit for, their ability to reshape a disappointing result into a new discovery or, in the vernacular, ‘make lemonade out of lemons’.

Here’s a link to and a citation for the research paper,

Selective isolation of gold facilitated by second-sphere coordination with α-cyclodextrin by Zhichang Liu, Marco Frasconi, Juying Lei, Zachary J. Brown, Zhixue Zhu, Dennis Cao, Julien Iehl, Guoliang Liu, Albert C. Fahrenbach, Youssry Y. Botros, Omar K. Farha, Joseph T. Hupp,  Chad A. Mirkin & J. Fraser Stoddart. Nature Communications 4, Article number: 1855  doi:10.1038/ncomms2891 Published 14 May 2013

This article is open access.

Love, hate, and the whole damn thing affect batteries, semiconductors, and electronic memory

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A Jan. 24, 2013 news item on ScienceDaily features love triumphing over hate where tetracationic rings are concerned,

Northwestern University graduate student Jonathan Barnes had a hunch for creating an exotic new chemical compound, and his idea that the force of love is stronger than hate proved correct. He and his colleagues are the first to permanently interlock two identical tetracationic rings that normally are repelled by each other. Many experts had said it couldn’t be done.

On the surface, the rings hate each other because each carries four positive charges (making them tetracationic). But Barnes discovered by introducing radicals (unpaired electrons) onto the scene, the researchers could create a love-hate relationship in which love triumphs.

The Jan. 24, 2013 Northwestern University news release by Megan Fellman, which originated the news item, probes into the nature of the problem and its solution (Note: A link has been removed),

Unpaired electrons want to pair up and be stable, and it turns out the attraction of one ring’s single electrons to the other ring’s single electrons is stronger than the repelling forces.

The process links the rings not by a chemical bond but by a mechanical bond, which, once in place, cannot easily be torn asunder.

The study detailing this new class of stable organic radicals will be published Jan. 25 [2013] by the journal Science.

“It’s not that people have tried and failed to put these two rings together — they just didn’t think it was possible,” said Sir Fraser Stoddart, a senior author of the paper. “Now this molecule has been made. I cannot overemphasize Jonathan’s achievement — it is really outside the box. Now we are excited to see where this new chemistry leads us.”

…

The rings repel each other like the positive poles of two magnets. Barnes saw an opportunity where he thought he could tweak the chemistry by using radicals to overcome the hate between the two rings.

“We made these rings communicate and love each other under certain conditions, and once they were mechanically interlocked, the bond could not be broken,” Barnes said.

Barnes’ first strategy — adding electrons to temporarily reduce the charge and bring the two rings together — worked the first time he tried it. He, Stoddart and their colleagues started with a full ring and a half ring that they then closed up around the first ring (using some simple chemistry), creating the mechanical bond.

When the compound is oxidized and electrons lost, the strong positive forces come roaring back — “It’s hate on all the time,” Barnes said — but then it is too late for the rings to be parted. “That’s the beauty of this system,” he added.

Most organic radicals possess short lifetimes, but this unusual radical compound is stable in air and water. The compound tucks the electrons away inside the structure so they can’t react with anything in the environment. The tight mechanical bond endures despite the unfavorable electrostatic interactions.

The two interlocked rings house an immense amount of charge in a mere cubic nanometer of space. The compound, a homo[2]catenane, can adopt one of six oxidation states and can accept up to eight electrons in total.

“Anything that accepts this many electrons has possibilities for batteries,” Barnes said.

“Applications beckon,” Stoddart agreed. “Now we need to spend more time with materials scientists and people who make devices to see how this amazing compound can be used.”

For anyone interested in the details of the work, here’s a citation and link to the paper published in Science,

A Radically Configurable Six-State Compound by Jonathan C. Barnes, Albert C. Fahrenbach, Dennis Cao, Scott M. Dyar, Marco Frasconi, Marc A. Giesener, Diego Benítez, Ekaterina Tkatchouk, Oleksandr Chernyashevskyy, Weon Ho Shin, Hao Li, Srinivasan Sampath, Charlotte L. Stern, Amy A. Sarjeant, Karel J. Hartlieb, Zhichang Liu, Raanan Carmieli, Youssry Y. Botros, Jang Wook Choi, Alexandra M. Z. Slawin, John B. Ketterson, Michael R. Wasielewski, William A. Goddard III, J. Fraser Stoddart. Science 25 January 2013: Vol. 339 no. 6118 pp. 429-433 DOI: 10.1126/science.1228429

This is paper is behind a paywall.