My Favorite Reaction’s Not A Reaction
Sep26

My Favorite Reaction’s Not A Reaction

As 7-Up was once called the “Un-Cola,” I am going to call my favorite reaction for CENtral Science’s Chemistry Blog Carnival the “Un-reaction.” When I was a graduate student and then postdoc, I wasn’t a synthesizer of things—I was a studier of molecular interactions: drugs sticking to DNA, proteins sticking to surfaces, lipids assembling into cell membrane mimics.   Some in the field might think this makes me an “un-chemist,” but I was indeed trained as a legitimate one. I was a physical chemist, which means that I still have books on my shelf with fun titles such as “Introduction to Electrodynamics,” “Symmetry and Spectroscopy,” and “Lasers in Chemistry.” It also means that I spent a lot of time in the dark and used physics-based tools in my work. Lasers, for instance. Spectroscopists in particular couldn’t survive without ‘em. My favorite laser would have to be the “HeNe” (pronounced hee-nee). That’s “helium neon” to all you synthesizers of compounds out there. In the lab, HeNe lasers are indispensible for their ability to help spectroscopists align optical tables. For instance, when you’re working with a high-repetition Nd:YAG laser, which puts out not-visible-to-the-naked-eye near-infrared light that can burn things (hair, especially, if you don’t tie it up in a ponytail while leaning over the optics), you want a visible, non-dangerous stand-in to put all the mirrors and lenses you’re using in place. Only then can you safely send the high-powered beam bouncing along down the optical pathway toward your sample. HeNe lasers are great stand-ins. And they work by electronic excitation and collisional energy transfer. That might not be a reaction in the purest sense of making and breaking bonds, but you’ll have to forgive this un-chemist for bending the rules of the Carnival a little bit. The first HeNe ever constructed was also the first available commercially—in 1962. It was then, and is still, composed of a small glass tube filled with, you guessed it, helium and neon atoms. An electrical discharge excites the electrons of the low-pressure helium atoms, which then collide with the neon atoms and their electrons, passing along the “excitement.” This energy transfer is possible because helium’s excited state is close in energy to neon’s. Excited-state neon atoms accumulate, creating what’s called a population inversion, and eventually, with nowhere left to go but down, they emit light and drop to an intermediate energy level before bumping up against the tube walls, releasing further energy in collision and reaching ground state. The burst of light the neon atoms emit is a red shade—632.8 nm—based on the difference in energy levels of their excited and intermediate states. Other...

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The Ozone Zone
Sep26

The Ozone Zone

I chose my favorite chemical reaction based purely on aesthetics. Ozonolysis, wherein ozone—that tricky triumvirate of oxygen atoms—slashes its way through double bonds to make aldehydes, ketones, and carboxylic acids. Most synthetic organic chemists make things, but ozonolysis has a certain destructive appeal. Plus, there’s the pretty blue color that the solution takes on when the alkene is consumed, a sight not common to the largely colorless reactions of organic chemistry. My graduate work involved making analogs of Vitamin D to fight, among other things, cancer. We started the synthesis of our analogs by taking commercially available Vitamin D2, and using ozonolysis to break it into its components like so: I was after the molecule’s fused ring system. I’ll never forget when the senior graduate student teaching me how to use the ozonolysis setup placed a latex glove in front of the O3 stream to show me the potential hazards of not paying attention to her instructions. The air stream ripped the glove to shreds in a matter of moments. The reaction also features a nifty mechanism bound to show up on O-Chem exams: There’s the 1,3-dipolar cycloaddition (love to draw those leaping arrows), which leads to molozonide. Wikipedia shows this intermediate breaking into a carbonyl and a carbonyl oxide, which then undergo another 1,3-dipolar cycloaddition to produce a trioxolane (Or is it an ozonide? Nomenclature was never my strong suit). I, however, prefer the drawing that appeared in my O-Chem text (Morrison & Boyd), where an oxygen atom appears to shimmy its way through the C-C bond:   As an aside, you should know that “What’s your favorite chemical reaction?” is not a great conversation starter. I tried it last weekend with my husband and was met with...

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Chemistry Cartoons For IYC 2011
Sep23

Chemistry Cartoons For IYC 2011

For a little Friday afternoon fun, I thought I’d share some chemistry cartoons that came across the Newscripts desk recently as part of an International Year of Chemistry competition. Sponsored by the Physical & Biophysical Chemistry Division of the International Union of Pure & Applied Chemistry (IUPAC), the contest asked participants to submit cartoons illustrating a chemical principle “that would be clear and accessible to the general public.” The international panel of judges accepted entries from Jan. 1 to May 31 and awarded prizes during the 43rd IUPAC Congress in Puerto Rico in early August. Even though my personal favorite (shown above to the right) among the six winners didn’t take home the grand prize, it did win a merit award for Bruno Demoro, a graduate student at Uruguay’s University of the Republic. As a physical chemist, I enjoyed the humor, although I suppose the general public might not get the reference to “degenerate” orbitals. Just us geeks here in the Newscripts gang. Five students received merit awards of $100 for their entries, and one lucky winner—high schooler Jessica Hough of Valley Central High, in Montgomery, N.Y., took home $1,000 for her illustration entitled “Chemical Attraction.” On the basis of the success of the contest, IUPAC’s Physical & Biophysical Chemistry Division says it plans to run an annual student chemistry cartoon competition. So check in with the organization early next year for...

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Chemistry Cartoons For IYC 2011
Sep23

Chemistry Cartoons For IYC 2011

For a little Friday afternoon fun, I thought I’d share some chemistry cartoons that came across the Newscripts desk recently as part of an International Year of Chemistry competition. Sponsored by the Physical & Biophysical Chemistry Division of the International Union of Pure & Applied Chemistry (IUPAC), the contest asked participants to submit cartoons illustrating a chemical principle “that would be clear and accessible to the general public.” The international panel of judges accepted entries from Jan. 1 to May 31 and awarded prizes during the 43rd IUPAC Congress in Puerto Rico in early August. Even though my personal favorite (shown above to the right) among the six winners didn’t take home the grand prize, it did win a merit award for Bruno Demoro, a graduate student at Uruguay’s University of the Republic. As a physical chemist, I enjoyed the humor, although I suppose the general public might not get the reference to “degenerate” orbitals. Just us geeks here in the Newscripts gang. Five students received merit awards of $100 for their entries, and one lucky winner—high schooler Jessica Hough of Valley Central High, in Montgomery, N.Y., took home $1,000 for her illustration entitled “Chemical Attraction.” On the basis of the success of the contest, IUPAC’s Physical & Biophysical Chemistry Division says it plans to run an annual student chemistry cartoon competition. So check in with the organization early next year for...

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What’s In A Name? For Chemists, Their Field’s Soul
Aug03

What’s In A Name? For Chemists, Their Field’s Soul

This post was originally published at Scientific American’s Guest Blog. Don’t forget to check out all the contributions to the Scientific American Blog Network’s Chemistry Day! By 1992, the Soviet Union was formally dissolved, and the entire world’s political, economic, and military alliances were in the throes of transformation. But you could forgive officials at the International Union of Pure and Applied Chemistry (IUPAC) if they didn’t notice much of a difference. At the time, they were still embroiled in a very Cold War-era standoff. At issue was one of the biggest prizes in the field of chemistry– naming rights for new elements in the periodic table. In the 1960s, American and Russian laboratories both laid claim to the discoveries of elements 104 and 105. And IUPAC had to play the role of arbiter. It took until 1997 to sort out the squabble, and along the way, several other new elements got dragged into the controversy, which some nuclear chemists dubbed the Transfermium Wars. In the end, the Americans got their way on element 104, which was officially named Rutherfordium, in honor of British chemist and physicist Ernest Rutherford. Element 105, Dubnium, is named for the Russian town of Dubna. Belying the decades-long conflict, IUPAC explained its decision in rather understated terms: The Commission hopes that the present collection of names will be accepted as a fair compromise between the various claims and suggestions. A Bunsen burner, named for German chemist Robert Wilhelm Eberhard Bunsen (Wikimedia Commons/NASA) All researchers name the trappings of their discipline– whether elements, equations, or species. To some extent, the naming happens as a matter of convenience, as a form of shorthand to convey a complex concept to a fellow scientist. But hidden within those monikers are the stories of science: sweeping triumphs, competition, the ascent of young stars. Chemists have a particular affinity for names– they name not only their elements but also their lab equipment, their reactions, their catalysts, even portions of catalysts called ligands, which modify catalyst activity. Unlike the elements, these namings aren’t regulated by IUPAC. Instead, they’re an informal process dictated by the community that plays out in the scholarly literature, in books, and at conferences. As a result, they are a fascinating window on how discoveries in chemistry become chemistry fundamentals, not to mention a way to learn the tales of legends in the field. Among the simplest examples of 2010’s Nobel-winning chemistry Consider 2010 chemistry Nobel Laureate Richard Heck, retired from the University of Delaware. Heck shared the prize with Ei-Ichi Negishi of Purdue University and Akira Suzuki of Japan’s Hokkaido University. Each of the three chemists has...

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CENtral Science Represents at Scientific American Blogs’ Chemistry Day
Aug02

CENtral Science Represents at Scientific American Blogs’ Chemistry Day

Devoted CENtral Science followers may recall two posts about a big development in the blogosphere that went up at Terra Sigillata last month. There, my esteemed blog colleague David Kroll played host to a vibrant discussion about the shiny new Scientific American blog network– of course congratulating the massive effort on the part of Chief Editor and Community Manager Bora Zivkovic and many others that led to its creation, but also noting the paucity of chemistry blogs on the high-profile new network. The discussion spilled over into other prominent blogs, including those of American University chemist Matt Hartings and San Jose State U. professor of philosophy (and physical chemist by training) Janet Stemwedel. Well, SciAm’s blogerati were clearly listening. Today, in honor of the International Year of Chemistry and the IUPAC World Chemistry Congress in Puerto Rico, it’s all chemistry all day today at the Scientific American blog network. What exactly does that mean? A smorgasbord of chemistry blog posts, both from regular SciAm contributors and guest bloggers. There’s even a Twitter hashtag, #SciAmChem. Bora has put together the master list of posts. I’m a bit biased, but I’d like to highlight two of them: From CENtral’s own David Kroll: Drugs From The Crucible of Nature Bora was even nice enough to extend me an invitation to guest blog with this illustrious group. It’s an honor to blog about one of my favorite topics, named reactions, for Scientific American. From C&EN’s own Carmen Drahl: What’s In A Name? For Chemists, Their Field’s Soul Of course, scores of other great posts are on the list, including writing from Hartings, Stemwedel, Ashutosh of Curious Wavefunction, Deborah Blum of Speakeasy Science, Antony Williams of ChemSpider/ChemConnector and SciAm blogger Michelle Clement, who works for the American Chemical Society. It’s been a great day for chemistry blogging. But C&EN Assistant Managing Editor Amanda Yarnell put it best this morning on Twitter: amandayarnell: Grt posts on @sciamblogs today by @discodermolide @sciencegeist @chemconnector & more. Here’s to hoping there’s not just 1 day of...

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