MODERN CHEMISTRY: AN INTRODUCTION
Welcome to the world of modern chemistry. To help you make sense of this important and fast-changing field of study this program has two parts. Part One will take you on a brief tour of the history of chemistry. Part Two will introduce you to some working chemists today.
So let’s get started.
Part 1: A Brief History of Chemistry
Chemistry, like the other sciences, has always had two sides, wonder and power. On the power side the chemists of yesterday were the people who learned how to make and control fire. The people who learned how to extract copper, tin, and iron from the rocks beneath their feet. The people who learned how to make beautiful, long-lasting ceramics in China, long before the western world achieved such mastery.
On the wonder side, the first chemists were more like philosophers. Natural philosophers they were called in ancient Greece. Men like Democritus, the laughing philosopher, who would sit here in the central market place of Athens and ask questions like, "What is the world made of?' And he would answer his own question with a new word-"atoms."
The world, and everything in it-earth, air, water, fire, leaves, animals, people too are all made of very small particles called atoms. It is the wandering of these tiny atoms, into and out of all things that creates the wonder that is our world.
Unfortunately these natural philosopher scientists had little connection to the men and women who mined the metal ores, made the cotton cloth, molded the shiny ceramics. Unfortunately the world had not yet caught on to the central idea of science- putting ideas to the test of fact. Scientific method had not yet been born. And scientific method would not be born for another thousand years.
Modern chemistry owes a great deal to the men called alchemists who lived and worked in medieval times in Europe, in China and in the vast Islamic empire which stretched from Spain in the west to India in the East. Sometimes these alchemists were more like magicians than scientists, but they were also the first to devise ingenious ways of distilling liquids, of making acids and bases, of preparing medicines and of making ever tougher and sharper metals.
Alchemists in Europe learned much of their craft from Arab alchemists but they also began to make their own contributions. They discovered, for instance how to make sulfuric acid, nitric acid, alcohol, sal ammoniac and many other new salts. These early alchemists also learned (probably from the Chinese this time) how to mix sulfur, charcoal and saltpeter to make gunpowder, the chemical product that more than any other single thing led to the end of the feudal system and the birth of the modern world.
That modern world-our modern western world-came directly out of what is called the Renaissance. This was the time of Michelangelo, Botticelli, Gutenberg and Vivaldi, The Renaissance was also the time of Copernicus, Galileo, Kepler and Isaac Newton. Scientists who made the great leaps forward in physics, mathematics and astronomy, taking the earth out of the center of the universe and sending it in orbit around a medium sized star at the far edge of the milky way galaxy.
The science of chemistry, however, has to wait another two hundred years before beginning its leap into modern times. It was in 1661 (about the time the American continent was first beginning to be settled by European immigrants) that Robert Boyle in England published the first really scientific book about chemistry, “The Sceptical Chymist. ” In his book he described the famous Boyle’s law of gases and more important, he gave the first clear scientific definition of an chemical element.
An element, he said, was any substance that could not be broken down into any simpler substance, but that could only be combined with other elements to make compounds. Boyle however had no way of knowing or discovering just which substances were elements, nor how many elements there might be in the world.
You remember, I said that the first chemists were probably the ancient people who discovered how to make and control fire. Strangely enough, it was this very same problem, fire, that led to the real birth of modern chemistry just about the time of the American Revolution.
One of the men who did the most to help solve the problem of fire lived here in what was then a frontier settlement in Pennsylvania. Joseph Priestley was a Unitarian minister and a friend of Benjamin Franklin. He moved here from his native England to escape persecution for his liberal political views. Like most chemists of his day, Priestley was an amateur. He had no training at all in chemistry and did not even begin any chemical studies until he was thirty eight years old. In his laboratory here in Pennsylvania, and before that in Birmingham, England,
Priestley discovered a whole new world of gases. He was the first to isolate nitric oxide, carbon monoxide, sulfur dioxide, hydrogen chloride, ammonia and most important of all, oxygen. Along the way he made the first bottle of soda pop!
At about the same time another amateur, an eccentric English millionaire, Henry Cavendish, added other important clues. Cavendish discovered the element hydrogen, and proved that water was not an element after all, but a compound of hydrogen and oxygen.
It remained for a brilliant French aristocrat, Antoine Lavoisier, to fit the new pieces together and solve the great mystery of fire. Chemists before Lavoisier had always had the common sense view that fire was the breaking apart of a substance. Some fiery part escaping from a combustible material. Chemists even had an impressive sounding name for the fiery part. They called it "phlogiston."
Lavoisier, after a long series of careful experiments in his Paris laboratory (aided by his wife) came to a different conclusion. If you burned mercury, or tin in an enclosed space, as Lavoisier did in a classic experiment, you always found that the air above the burning metal decreased in volume by about one fifth. And you always found that the metal increased in weight after being burned. If burning was phlogiston leaving, could phlogiston weigh less than nothing?
Of course not, said Lavoisier. We have got it backwards. What happens in burning is not a breaking apart, but a coming together. In other words, when something burns it combines with that new gas Priestley discovered, and which makes up a good part of air, approximately one fifth! We call this gas, oxygen. Fire is not phlogiston escaping. Fire is oxygen combining. Fire is what we now call oxidation.
Lavoisier even carried this into living chemistry, showing that a similar kind of “living fire" takes place inside us. We call it respiration. Chemistry was on its way to becoming something more than an alchemist's cookbook of exotic recipes. And this man, a poor English elementary schoolteacher named John Dalton, took the next big step forward just a few years later. Dalton invented what we now call atomic theory, the backbone of modern chemistry.
In between taking his young students on outings to nearby ponds and rivers, Dalton taught himself chemistry. Unlike Priestley, Cavendish and Lavoisier, Dalton was clumsy and unskilled in the laboratory. But in the study he shone, explaining in theory what other had discovered in fact. His first study was here at s small Quaker school in Kendall on the border of the beautiful lake country in northwestern England.
Dalton’s idea of the atom was similar to that of Democritus but there was one enormous difference. Dalton had solid evidence to back him up. Why not imagine, said Dalton, that all these elements chemists are discovering nowadays are themselves made of particular kinds of simple atoms. Atoms that might look like these round balls, models he himself made and now on view in a London museum. See how that simplifies things, he pointed out.
Water, for instance. Cavendish proved that water is made of hydrogen and oxygen, two parts hydrogen to one part oxygen. Dalton showed how this could happen. Each atom of oxygen must combine with two atoms of hydrogen to make one molecule of water. Similarly for other substances. Chemists knew they always combined in simple whole number ratios. Dalton explained why this had to be so. True, no one could yet see, taste, touch or smell these tiny atoms.
After Dalton, however, the atom idea proved to be one of the most useful in all scientific history. After Dalton, too, a new element, a new kind of atom, was discovered every few years. And new compounds and new reactions were discovered in nature and made in the laboratories.
The big breakthroughs of Cavendish, Priestley, Lavoisier and Dalton all happened at the end of the 18th and the beginning of the 19th centuries. These important breakthroughs however were still mostly in the world of pure theoretical science. The wonder side of science, in other words, had taken a giant leap forward, but the power side was still lagging behind. New knowledge of elements and compounds, of atoms and molecules still was of only marginal help to human beings in their daily struggles for existence.
All that changed in the 19th century as the power side of chemistry took giant leaps forward as well. In 1830 Friedrich Woehler, a young German chemist, made a shocking discovery. He made urea in a test tube. Almost all chemists of his time believed that living creatures had a special mysterious "life force" that enabled them to make living chemicals like urea. When Woehler made it in a test tube instead, the life force theory was proven false and the way was open to what we today call biochemistry, the chemistry of living things.
A few years later the French chemist, Louis Pasteur, took a giant step forward in the power side of chemistry. For all of human history until Pasteur’s day, disease epidemics had over and over again maimed and killed many more people than wars. And no one knew why. Pasteur used his knowledge of chemistry to find the first scientific answers to disease first in plants (he saved the French wine industry by discovering what was contaminating their fermentation tanks), in animals (he discovered how to prevent anthrax in sheep), and in human beings (he discovered how to cure rabies). Here was a case where at last the power and the wonder of science joined hands to give genuine help to human beings.
Hippocrates, a thousand years before, had said diseases have natural causes and must have natural cures. Pasteur, in the mid-nineteenth century, found some natural causes -- bacteria and viruses -- and invented some natural cures --inoculations.
Building on Pasteur’s germ theory of disease other chemists, biologists and medical researchers were able to find ways to slow down and then to conquer deadly diseases like anthrax, rabies, diptheria, smallpox, tuberculosis, plague, polio-- diseases that had routinely wiped out a third to a half of many communities in Europe, Asia, Africa and the Americas. As the cynic H.L. Mencken wrote later, “It was the most noble chapter in the history of mankind.”
At about the same time, the middle of the nineteenth century, a bearded Russian came along to make another historic breakthrough in pure theoretical chemistry. Dmitri Mendeleev worked in St. Petersburg searching for a better way of organizing all the fast growing new chemical knowledge. Mendeleev loved chess and card games. He would write down the names and atomic weights and properties of all the known elements (about 63 at that time) on blank cards. He would shuffle the cards and lay them out in a thousand different patterns.... trying to find a pattern in nature.
When he arranged the 63 known elements in rows of seven across, he noticed that the columns down always had elements that had much in common with one another. But occasionally there was a gap. He took a bold guess. "There is an element as yet undiscovered," he predicted. In fact there were three gaps. He predicted three undiscovered elements. And he predicted boldly what they would be like once they were discovered! All three were found, just as he predicted.
Mendeleev's Periodic Chart of the Elements was a scientific triumph. Just as gunpowder had destroyed the feudal manors, so chemists, physicists and self-taught inventors like America’s Thomas Edison used these new ideas to create the new metal alloys, chemicals, textiles, drugs and fuels that supported and powered the industrial revolution, a revolution that transformed western Europe and North America in the nineteenth century. And then just when chemists thought they had it all figured out about hundred years ago-new shocks, new opportunities!
A German physicist, Wilhelm Roentgen, was experimenting with high voltage vacuum tubes at the University of Wurzburg in Bavaria. He found some strange, penetrating, invisible rays coming out of the tubes. Rays that easily penetrated right through the skin of people, giving a picture of their bones. He called his mysterious rays, x rays. His x rays quickly became world famous. The question for science was-what were they? Where were they coming from? Where did they fit on the periodic chart?
Within months came more starling news from Paris where Henri Becquerel found that a chunk of uranium would darken photographic plates. At the same time Marie and Pierre Curie at the University of Paris were working in this garage and finding still more rays and other strange penetrating particles coming out of another new element they themselves discovered-radium. These rays and particles, scientists began to see, must be coming right out of the atom itself.
The atom was not a billiard ball as pictured by Dalton. Instead,inside each and every atom, there must be a structure as intricate as a fine watch. As chemists and physicists began taking apart that watch, they found protons, electrons, neutrons, energy levels and sophisticated bonding rules. And from this new atomic theory would come electronics, nuclear power and the marvelous new world of modern chemistry.
Modern alchemy. For indeed the late twentieth century chemist is heir to the old alchemist tradition. Using models, computer simulations and imagination, as well as old fashioned test tubes, beakers,and laboratory equipment, the modern chemists combine the wonder and power of new chemical bonding knowledge to perform modern chemical magic transforming one material into another, creating a cornucopia of new materials never before seen on earth.
Let's look at some of these modern wizards now. What makes them tick? How do they do what they do? Why do they do what they do? We'll learn something of all these things in Part Two of MODERN CHEMISTRY.
Part 2: Working Chemists Today
"We’ll start with a very simple experiment. I take a match, strike it, and light a candle. ..Not very exciting. Everyone has done this. ... But have you ever wondered why the candle stays lit?.
"... can't be done. This is why. All these reasons. An example of fallible thinking. You can’t do this because ... In my naivete at least in the beginning, I did it anyway."
"Alzheimer's disease is diagnosed by the presence of deposits in the brain called amyloid plaques. ... So one of the things we're looking for is how these plaques form. And why. Cause if you can figure that out you can figure out how to stop it."
"I recall being as old as sixteen and being asked what I was going to be and I didn't have an idea. I did realize that I wanted to do something that was related to chemistry. “
"the sequence of all the genes encodes the structure of all the proteins .. Sort of minimal fundamental building blocks.”
"When I was in high school I knew I wanted to do something in the medical area ... I did like chemistry.”
"We’ll start with alcohol. Alcohol is a carcinogen. I didn’t know that alcohol was a carcinogen, but there is very very good evidence that alcohol is a carcinogen.”
“Everything we've done in the lab has been fun whether it works or not. Some things are more fun than others."
There is a great secret about modern chemistry. About science as a matter of fact. Whether it's fair to get paid so well for having so much fun. Of course chemists are paid well not for having so much fun, but for being of service to others. Let's look and listen to some modern chemists tell about their work.
Some chemists today work directly in universities and in industry to produce useful new products. Others, like Dr. Bassam Shakishiri, a chemist at the University of Wisconsin work to gain new basic knowledge and to educate future chemists as well as scientifically literate citizens. Here he shows one of the demonstrations he uses in his famous nationally televised Christmas lecture, “Once upon a Christmas cheery in the lab of Shakashiri.” And he explains why science is fun.
“We put it in there. The second component is also clear and colorless. And the third component we have which is also clear and colorless and we watch ... A lot if interesting things seem to be happening. The initial color was clear and colorless. Now it’s light blue, then it’s also clear and colorless again and then the yellow color appears. This is an example of what is called a chemical oscillating system.
It’s a fascinating system. It’s one of a family of oscillating reations. It is one of about fifty known such reactions and this one is special It’s very special to me for two reasons. The first reason is that it was discovered by two high school teachers. In 1973 they published a paper in the Journal of Chemical Education about this beautiful system. In fact this reaction is named after them. It’s called the Briggs-Rauscher Reaction. And it wasn’t until 1982, nine years later that some high powered scientists, chemists, published a paper describing mathematically what this beautiful reaction is all about. That’s why science is fun. That’s why it is fascinating!”
On the practical side, Spencer Silver is an industrial chemist at the 3M company in St. Paul, Minnesota. He was the chemist who discovered the sticky glue that made Post-It Notes possible, those peel-off pads that are now sold world-wide. When we contacted him in St Paul he told us how he did it.
"I discovered the adhesive in 1968. It was a eureka in terms that, wow, this was really different. I took it to a bunch of my colleagues. I was fairly new at industrial research in those days. I said what do you think of this? Everybody said this kind of experiment can't be done. This is why. All these reasons. An example of fallible thinking. In my naivete, I just did it anyway.
“I really get a kick out of observing something that I've made becoming a product. It’s very enjoyable. When I first came here I thought, there's nothing to it. Just make something and someone sells it. Now I realize all the people involved, the money, the time involved in making that happen. Now the most difficult part, the part people should realize about industrial research, once you've found this better mousetrap, you've gotta find somebody willing to manufacture it, do the marketing, do development work. And that is really tough."
Dr. Silver is an example of an industrial chemist making a new kind of product based on a chemical discovery. Dr. Lloyd Smith is a chemist who has specialized in inventing not a product, but an automated technique for carrying out the most ambitious biological study of all times--s equencing the human gene pool. This multi-year project called the Human Genome Project was just successfully completed in the early 21st century. Like many chemists (and scientists in other fields today) Dr. Smith has also used his knowledge and talents to help form high-tech companies near the college campus to produce new products of use and profit. He explains one example.
“Another company I work with, Visible Genetics, has been doing sequencing of the retino blastoma gene. That is a gene that is involved in the generation of cancer of the eye and it turns out that if you’re in a family that has that gene and you don’t do any genetic testing then you don't know which of your children have that gene and which don't. And it turns out since you don't know what you have to do is end up having to do these examinations of the eye under general anaesthesia which are pretty expensive and they have to do them every six months on young children to detect if there is going to be an early occurrence of eye cancer...
“Visible Genetics put out this test that allows them to go in and rapidly sequence those genes from the affected members of the family. Once they do that they can find out what the mutation is in the gene that's causing the problem and that allows them to go and very quickly and easily test the children and find out which children have the bad gene and which don’t. The ones that don’t are right away free and clear. They're out of it. No test, no general anaesthesia, no anxiety. ...
“And the ones that do, you can also begin building up a data base to look at what the prognosis is based on different types of mutations and also try to tailor treatment that is specific for those mutations."
Dr. William Barnes at the University of Northeastern Illinois is a biochemist who teaches and does research on asbestos and other environmental chemicals. I had heard that there were different kinds of asbestos. I asked Dr. Barnes about this.
“Yes, there are different kinds of asbestos. They are all cilicates and they’re hydrated cilicates associated with iron. Some have particles that are more curly than others and some are more fibrous. It appears that the more fibrous kinds are the more toxic ones.”
Dr. Barnes is experimenting on ways to help the lungs recover from asbestos exposure. Of course the best thing would be to not get exposed in the first place. I asked him what his research has indicated about the value of eliminating asbestos from schools and other buildings.
“Yes, there is a controversy. At this time we are under mandate to remove asbestos from public buildings. On the other hand it seems that the kind of or form of asbestos in public buildings are the ones that are the least toxic. I would say that we are at higher risk for lung injury from cigarette smoking and it has become evident that even persons in the environment of cigarette smoking are at higher risk than that of asbestos in public buildings.”
I asked Dr. Barnes how he got interested in science and how he got started as a scientist?
"I got the impression when I was quite young that they would have liked for me to become a medical doctor. I felt some pressure as I was growing up, but I was always interested in investigating things. How do they work. ... I recall being as old as sixteen and being asked what I was going to be and I didn't have an idea. I did realize that I wanted to do something that was related to chemistry. ... but it wasn't until I got to college that I realized I wanted to major in chemistry and got very interested in research. It was after that that I realized that chemistry was indeed the right track, but I wanted to apply what I knew chemically to something that was living. So that brought me to biology."
African-americans and other minorities are underrepresented in science today. What do you think can be done about that?
"I think part of the reason is related to the fact that minorities in general are exposed more often to professions like doctors or lawyers-the TV will do that -but they seldom get to appreciate the relationship between experimentation and things that go on in society in general. I think we need to move to the neighborhood or the schools to expose the student at a very early age.
To how much fun science can be?
"It is fun. Sometimes it's frustrating too, but it's fun in that it's usually territory that has not been covered previously. It gives you a feeling of fitting in, so to speak, and you have a place. And new ideas are coming out. It gives you that feeling that you have made a contribution."
Most people today think of chemicals as man-made things that come out of scientific laboratories. Bruce Ames, a world famous biochemist at the University of California-Berkeley, never tires of pointing out that everything in the world, non-living and living, is chemicals. All things, in other words, are built, are made of chemicals, natural chemicals. And that natural chemicals besides being way way more common and numerous than man-made ones, can also be at least as deadly. In other words, despite advertising hype, “natural” is no assurance of quality or of safety. One of Dr. Ames’ most important contributions to science and society has been the Ames Test, a standard test used around the world to see whether a chemical, any chemical, natural or man-made, could cause cancer. Here he explains how he invented the Ames Test.
“I was reading all the labels on boxes of potato chips and seeing they had passed laws that said they had to list every ingredient and I became interested in all the compounds and wondered whether any of them might be mutagens, which is chemicals that damage the genes and wondering what would happen if something came into the environment that was a strong mutagen that we didn’t know about. I started playing around with a test that could tell whether a chemical was mutagen, chemical that damage the genes. And what we ended up doing was developing a test that could detect mutagens in bacteria.
“You put a billion bacteria on a petri plate and have them mutate to start with so they can’t grow and if you mutate them back to normal they can grow and you see a colony and you can count the colonies. So you can work out easy techniques.
“ .... In the course of that I became very interested in the relation of carcinogens to mutagens and we and other people showed that most carcinogens were really working as mutagens o you could detect there is one test which would just take an afternoon. We spent fifteen years developing ... this test was adopted to detect possible carcinogens and every industry in the world started using it. 3000 laboratories all over the world now use this test.”
You said earlier that smoking tobacco was the most definitely proven cause of cancer. But you also said that alcohol too was a carcinogen. How does drinking a few glasses of beer compare to the risk of PCBs or abestos or pesticides or whatever else might be polluting our soil or air and water?
“Nothing even comes close to alcohol when you look at the amounts. So it you put them in beer equivalents, all the pollution seems to fade away. The other thing is people have the idea that carcinogens are rare, they are mostly man-made and we can get rid of them. And that’s not true. Because 99.999% of the chemicals in the world are natural and natural chemicals, if you test them, if you ask what percent of man-made chemicals are carcinogens and what percent of natural chemicals are carcinogens, it’s about half for either one. That is, half the chemicals we ever tested come out as carcinogens among the natural group and about half of the man-made chemicals. So I think most of the carcinogens in the world re going to be natural and the natural substances are much closer to the toxic level than are the man-made ones. So we are just not getting enough of pollution to make a difference when you compare it to --cause every meal you eat is full of carcinogens!”
I know most toxicologists would agree with you that man-made chemicals are way down the list of possible carcinogens but that is definitely not what people around the country a nd the world seem to believe today. How come the sharp difference of opinion?
“Public opinion isn’t influenced by toxicologists. I think most ... For the last ten years newspaper articles have been having stories about a toxic chemical here and a toxic chemical there, pollution and carcinogens in the water. And most of this information comes from environmental organizations that have what I would consider a very extreme view about everything and I don’t think they are getting the general feeling of the scientific community on this ... Also the science is changing.”
As you can see, chemistry today is a crossroads for many sciences. It includes biology, physics, economics, technology, toxicology, agriculture and much more. Dr. Regina Murphy, researcher and professor at the University of Wisconsin-Madison is by training and degree a chemical engineer. She once worked in a large oil refinery. Today her research is directed to understanding more about the role of proteins in the human body, especially in the case of Alzheimer's Disease, a dread affliction of old people, and Down's syndrome, a genetic defect in newborn babies. I asked Dr. Murphy to explain her approach to Alzheimer's Disease and Down Syndrome.
"Alzheimers disease is diagnosed by the presence of deposits in the brain called amyloid plaques. They're extracellular, outside of the main cells, abnormal. It's not proven yet but a lot of people think that the plaques are an early stage of the disease. In fact, maybe the cause of the dementia, of all the problems patients have later. So one of the things we're looking for is how these plaques form and why. Cause if you can figure that out you can figure out how to stop it potentially or at least how to develop an earlier diagnosis so you can intervene with treatment sooner. One of the major components of the amyloid plaques is a protein called beta amyloid protein. That's what I'm studying.”
You are a chemical engineer. What is the difference between a chemist and a chemical engineer?
"Well some say ... chemists know things and engineers do things. That's probably a bit unfair. Engineers tend to be a lot more practical. In research you see a lot of overlap. Some people do different things. But if you're talking about people who don't do research but who are engineers, they tend to be working in chemical plants making products. That could be gasoline. It could be polyesters. It could be paper, drugs, food, all these kinds of fields. So engineers bring in some skills that chemists normally don't have so much. ... we also think in terms of processes. Chemical engineers think that ... well, if you start with something here, how does it get to someplace else. And chemists tend to, I think, think a little more about what am I looking at right now."
How did you get into this field? "I fell into it. When I was in high school I wanted to be either a writer or a journalist. Then talking to a friend she said you're really good at chemistry and math. I thought, well, maybe I am. No one had told me I was but actually I was probably better at that than English. So when applying to college I got lots of brochures from different colleges sent to me. I got one from MIT which I'd never thought of going to. I thought, well, I'11 apply there but I won't get in. But then I got in and said, OK, I'11 go for a year and flunk out and go some other school. But I didn't flunk out. ...
“I was kind of interested in chemistry. I didn’t know much about engineering. My father was a high school teacher, and he didn’t know what an engineer was either. ... I took a class my freshman year in chemical engineering and I loved it. Really fun and I saw it as something practical, useful that also involved a lot of the skills I liked, the chemistry physics, math, the whole combination. It wasn't esoteric, so far removed from anything that was part of daily life. It really was all about real things that people use every day."
DeAnne Liska is just beginning her chemistry career. She is a graduate student doing research for the first time. We asked her about research projects on vitamin K she is working on at the graduate level of a university. “In the university most people do more basic research. We are asking basic questions of how are these proteins made? How is vitamin K involved? How much vitamin K does a person need? How much do they get from their diet? How much do they get from the bacteria in their intestines and if you interrupt the vitamin K if you involved in the construction of these proteins. What does that do the person involved .. Will be applicable more clinically down the road, but the questions we ask is more directly how does blood coagulation work?”
What is it like in graduate school?
“Graduate school your life is always changing. What makes your life exciting is changes day to day when you are taking courses it’s exciting to get thru the courses and learning all the stuff you learn in the first two years you’ve covered so much biochemistry you have a background in it and it’s really exciting to be a part of that. Then you have teaching responsibilities that can be very rewarding. You get a chance to talk too people and see them get excited about the field too. And the research that for a lot of people and for myself too you get to a point where after a few years of graduate school you’re starting to do things that have never been done before and using techniques that you know better than anyone else and that’s really exciting. And when you start talking to people I’ve starting to get to this level right now ehnre they are asking you questions about how you do things and they’re telling you about what they do and you can learn and understand what they do and have ideas for other things that need doing.
“There are a lot of women in biochemistry now. Especially in my graduate department, fifty percent are women. There are not as many women professors right now but that is changing .”
Remember the candle that Dr. Shakashiri lit at the beginning of this program. He pointed out to us that there were hundreds of research questions about a simple experiment like a candle burning. Here is one example that has surprising implications today.
“I want to say one other thing about this candle. One of the products of combustion .. Coming out of that candle is soot,... Buckyballs.”
Our last chemist is a pioneer in the study of these Buckyballs. Let’s follow this story.
Over a hundred years ago a chemist in Germany figured out how carbon atoms hooked together in circles to make a liquid known as benzene. This discovery opened the way into a whole new world of modern carbon chemistry. Once chemists around the world knew the architecture they could proceed to create new kinds of carbon molecules and the result was hundreds of thousands of new substances never before seen on earth. Chemicals that would give us new sources of energy, new building materials, new ways to cure disease and new forms of art. Recently a group of physicists and chemists at the University of Arizona led by Donald Huffman found a way to make carbon hook together in a radically new way-a three dimensional soccer-ball shape. They called their new molecule Buckminsterfullerene, or Buckyballs for short.
Many people now think this new form of carbon will be as revolutionary in the coming decades as the discovery of benzene ring architecture was in the nineteenth century. This story is also a perfect example of the crossroads of pure basic chemistry and useful industrial chemistry. We interviewed Dr. Huffman in his laboratory office at the University of Arizona. Our first question was how did you make buckyballs?
“The story goes back a long time. Is really an example of perseverance and serendipity. We began studying carbon small particles in the early seventies in our lab here in Tucson. The way we did this is we took two carbon rods, imbedded them together and ran a large current through them in an environment of helium. This produced a soot smoke of carbon. We were interested because interstellar space grains are known to be rich in carbon. Studying these properties in the early 70s and producing soot most people didn't want to make in the labs.
“Then in 1982 I went to Germany on sabbatical, began working with my colleague Wolfgang Kratcher at the Max Planck Institute for Nuclear Physics in Heidelberg. There we decided we needed to study further carbon smoke cause we were interested in interstellar particles and there were still some unknown things. ... The big breakthrough actually came in 1990 about May when we realized working independently in our labs in Heidelberg and Tucson, it was possible to dissolve the Buckminterfullerene selectively in liquid such as benzene or toluene. In that case you mix the soot with benzene and it would produce a reddish liquid. This liquid would be Buckminsterfullerene dissolved. Then you filter out the black soot and you're left with pure Buckminsterfullerene. Then you could dry that and form little solid particles such as this no one had ever seen before.” W
hy are chemists all over the world so excited about this new molecule?
"Well, the reason is because this is a new building block for chemical compounds. One can make an analogy perhaps with the benzene ring. The benzene ring is six carbon atoms in a hexagonal array with hydrogens hanging out. The benzene ring was discovered in the early 1800s and it is now known to be the base for several million compounds, many of them natural, someof them artificial. What we have here now is a sort of three dimensional benzene ring.A very elegant structure made of sixty carbon atoms and the idea is that this may be the basis for many many organic compunds of a three dimensional nature just as benzene is the basis for compounds based on the six carbon ring.
“It's already been shown that one can attach hydrogens on the outside of this. That's the first new compound that's been produced, C60H36. Now the organic chemists are really working on this, they want to attach a tail of some sort. Then they can start attaching other organic members. Once you have a tail attached then the sky's the limit so to speak as far as how large a molecule one can begin to make. Also point out that there's not only the outside of this molecule that's very intriqueing for possible new chemistry but the inside.
“One of the unique things about the molecule is that it's the largest known totally enclosed caged molecule. Completely empty on the inside. A large enough enclosure here to easily encapsulate just about any atom and a number of small molecules. And then when you make a solid you have spaces in the interstices that you can fill. So you see there are many possibilities."
What would you say to yoong students just beginning their study of chemistry? What is the moral to your story?
"Well, I have given many many talks to groups .. From students in high school to adults. And I always like to have a moral to the story. The morals of my story are first of all that big bucks are not a prerequisite for good science. In other words we don't have to have millions of dollars to do good science. We had been working on this for twelve years before we even began to see anything new in it and twenty years before it was all over with.
“The second moral of the story is that everything-has not been discovered. A lot of kids get the idea that why go into science. Everything has been discovered already. Our story is one that shows that even something as basic as forms of carbon have not been discovered. There are many other things out there.
“Finally and most important, we already mentioned it's important to have fun in your work. We certainly have done that in all of that. This whole story has been just a real blast. Not just because we happened to be successful. We were having fun before we were successful: Everything we've done in the lab has been fun whether it works or not. Some things are more fun than others."