Mining, manipulating molecules

Sun Journal

Chemistry: The "central science" touches all aspects of modern life, as well as most other sciences.

July 10, 1999|By Tom Siegfried | Tom Siegfried,DALLAS MORNING NEWS

DALLAS -- More than any other science, chemistry provided the products that made the 20th century modern.

From plastics to Prozac, new chemicals from the lab invaded every aspect of ordinary life. Chemists produced new sources of clothes for people, tires and gas for cars, cures for diseases. Fertilizers, pesticides, refrigerants, birth-control pills, air conditioners and copy machines owe their existence to clever chemists.

It was just a matter of mastering the magic of molecules.

As the science in charge of understanding how molecules are made and what they do, chemistry touches all aspects of life, as well as most other sciences.

Chemistry is "the central science," says Stanford University chemist Carl Djerassi, who developed the first effective chemical for birth-control pills.

"It is the only science of molecules, and molecules are what we're dealing with."

Physics, he points out, is mostly concerned with the atom and smaller particles. Real life is more connected to chemistry. "We are molecular animals and not atomic animals," Djerassi says.

From silicon chips and xerography to the Polaroid camera, he says, "if you're talking about anything that revolutionized life in my lifetime, it's all chemistry."

Chemistry's 20th-century successes virtually all stemmed from understanding the way molecules are put together. In the 19th century, scientists developed methods for determining the atoms making up a molecule and, in some cases, how those atoms were arranged.

But the nature of the links, or "chemical bonds," holding the atoms together remained a mystery until the discovery of the electron in 1897.

Electrons are tiny particles, carrying negative electrical charge, that swirl around an atom's massive positively charged nucleus. Gradually chemists realized that because opposite charges attract, the negative charge of the electrons could serve as a sort of glue to hold the positively charged atomic cores together.

As understanding developed of how atoms are linked in molecules, chemists were better able to make new molecules to perform specific tasks -- or to make greater quantities of important natural molecules that are in short supply.

An early example was artificial rubber, invented in the 1930s. Rubber is a polymer -- a lengthy molecule made by connecting a string of small molecules like links in a chain. Mastery of polymer chemistry soon led to a potpourri of consumer products, such as nylon -- invented in 1935 by Wallace Carothers -- and a wide range of new plastics.

Of course, chemists did not limit themselves to inventing new products. Much chemical research was driven by an interest in understanding life. Today's knowledge of heredity, how the brain controls behavior and how living cells stay alive all depend on modern chemistry.

Probably the most dramatic examples of better living through chemistry came from pharmaceutical research, which provided a treasure trove of miracle drugs -- sulfa drugs, antibiotics and drugs for psychiatric disorders, such as fluoxetine (trade name Prozac), widely used to treat depression.

Many of these achievements depended on devising ways to build complicated molecules from scratch, or at least from simpler, readily available molecules. In a true mix of science, art and magic, chemists learned how to make such complicated molecular assemblies as Vitamin B-12, containing 181 atoms.

"We can pretty much design a synthesis for any molecule you can think of," says Nobel laureate Dudley Herschbach, a chemist at Harvard University.

While many chemists have worked on finding ways to synthesize known molecules, for fun or profit, some still seek novel molecules never before seen in nature or imagined in minds. In the late 1980s, IBM researchers discovered a new class of molecular arrangements that conducted electricity with no resistance at relatively high temperatures.

In 1985, researchers at Rice University serendipitously created a new molecule made entirely of carbon atoms connected in the shape of an ultraminiature hollow soccer ball.

Since it resembled the geodesic domes invented by the architect Buckminster Fuller, the scientists called the 60-atom molecule buckminsterfullerene ("buckyball" for short). Richard Smalley and Robert Curl of Rice with Harold Kroto from England won the 1996 Nobel Prize in chemistry for the buckyball discovery.

For all of chemistry's Nobel-winning successes, though, the science's image has suffered in the closing decades of the century.

The dark side of molecular magic struck often enough for the very word "chemical" to be considered derogatory -- despite the fact that all the natural substances of the living world are also, in fact, chemicals.

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