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The Same and Not the Same
Positioned at the crossroads of the physical and biological sciences, chemistry deals with neither the infinitely small, nor the infinitely large, nor directly with life. So it is sometimes thought of as dull, the way things in the middle often are. But this middle ground is precisely where human beings exist. As Hoffmann shows in his inspired prose, the world observed at its molecular level is complex and agitated, as are the emotions of the supposedly dispassionate scientists who explore it. In The Same and Not the Same the vital tensions of chemistry are revealed; with down-to-earth explanations, Hoffmann uncovers the polarities that power, rend, and reform the world of molecules. When we wash an apple before eating it, we are thinking not merely of the dirt that may still be on it but of the pesticides used in agricultural production. When we take medication, we expect relief for our pain but also fear side effects. The Same and Not the Same shows this ambivalence to be only one of a number of dualities pervading the world of molecules. The theme of identity, reflected in the title of the book, is central to the story. Other dualities, from stasis and dynamics, to creation and discovery to the rich complexity of revealing and concealing, are lucidly delineated for nonscientist and scientist alike. The Same and Not the Same also offers a rare and compelling personal statement of the social responsibility of scientists. Unabashedly confronting some of the major ethical controversies in chemistry today, the book strives for balance in facing the pressing ecological and environmental concerns of our time.
294 pages, Paperback
First published January 1, 1995
10 people are currently reading
303 people want to read
About the author
Roald Hoffmann
44 books13 followersRoald Hoffmann (born Roald Safran; July 18, 1937) is an American theoretical chemist who won the 1981 Nobel Prize in Chemistry. He is the Frank H. T. Rhodes Professor of Humane Letters, Emeritus, at Cornell University, in Ithaca, New York.
Hoffmann graduated in 1955 from New York City's Stuyvesant High School, where he won a Westinghouse science scholarship. He received his Bachelor of Arts degree at Columbia University (Columbia College) in 1958. He earned his Master of Arts degree in 1960 from Harvard University. He earned his Doctor of Philosophy degree from Harvard University while working under direction of subsequent 1976 Nobel Prize in Chemistry winner William Lipscomb. Under Lipscomb's direction the Extended Hückel method was developed by Lawrence Lohr and by Roald Hoffmann. This method was later extended by Hoffmann. He went to Cornell in 1965 and has remained there, becoming professor emeritus.
Hoffmann has investigated both organic and inorganic substances, developing computational tools and methods such as the extended Hückel method, which he proposed in 1963.
He also developed, with Robert Burns Woodward, rules for elucidating reaction mechanisms (the Woodward–Hoffmann rules). He also introduced the isolobal principle.
In 1981, Hoffmann received the Nobel Prize in Chemistry, which he shared with Kenichi Fukui "for their theories, developed independently, concerning the course of chemical reactions".
Other awards:
Priestley Medal (1990)
Arthur C. Cope Award in Organic Chemistry
Organic Chemistry Award (American Chemical Society), 1969
Inorganic Chemistry Award (American Chemical Society), 1982
Pimentel Award in Chemical Education (1996)
Award in Pure Chemistry
Monsanto Award
Literaturpreis of the Verband der Chemischen Industrie for his textbook The Same and Not The Same (1997)
National Medal of Science
National Academy of Sciences
American Academy of Arts and Sciences Fellow
American Philosophical Society Fellow
Kolos Medal
Foreign Member, Royal Society
Member of the Royal Swedish Academy of Sciences
Harvard Centennial Medalist
James T. Grady-James H. Stack Award for Interpreting Chemistry
Hoffmann is member of the International Academy of Quantum Molecular Science and is a member of the Board of Sponsors of The Bulletin of the Atomic Scientists.
In August 2007, the American Chemical Society held a symposium at its biannual national meeting to honor Hoffmann's 70th birthday. He also has served as a consultant with Eli Lilly and Company, a global pharmaceutical corporation.
Hoffmann graduated in 1955 from New York City's Stuyvesant High School, where he won a Westinghouse science scholarship. He received his Bachelor of Arts degree at Columbia University (Columbia College) in 1958. He earned his Master of Arts degree in 1960 from Harvard University. He earned his Doctor of Philosophy degree from Harvard University while working under direction of subsequent 1976 Nobel Prize in Chemistry winner William Lipscomb. Under Lipscomb's direction the Extended Hückel method was developed by Lawrence Lohr and by Roald Hoffmann. This method was later extended by Hoffmann. He went to Cornell in 1965 and has remained there, becoming professor emeritus.
Hoffmann has investigated both organic and inorganic substances, developing computational tools and methods such as the extended Hückel method, which he proposed in 1963.
He also developed, with Robert Burns Woodward, rules for elucidating reaction mechanisms (the Woodward–Hoffmann rules). He also introduced the isolobal principle.
In 1981, Hoffmann received the Nobel Prize in Chemistry, which he shared with Kenichi Fukui "for their theories, developed independently, concerning the course of chemical reactions".
Other awards:
Priestley Medal (1990)
Arthur C. Cope Award in Organic Chemistry
Organic Chemistry Award (American Chemical Society), 1969
Inorganic Chemistry Award (American Chemical Society), 1982
Pimentel Award in Chemical Education (1996)
Award in Pure Chemistry
Monsanto Award
Literaturpreis of the Verband der Chemischen Industrie for his textbook The Same and Not The Same (1997)
National Medal of Science
National Academy of Sciences
American Academy of Arts and Sciences Fellow
American Philosophical Society Fellow
Kolos Medal
Foreign Member, Royal Society
Member of the Royal Swedish Academy of Sciences
Harvard Centennial Medalist
James T. Grady-James H. Stack Award for Interpreting Chemistry
Hoffmann is member of the International Academy of Quantum Molecular Science and is a member of the Board of Sponsors of The Bulletin of the Atomic Scientists.
In August 2007, the American Chemical Society held a symposium at its biannual national meeting to honor Hoffmann's 70th birthday. He also has served as a consultant with Eli Lilly and Company, a global pharmaceutical corporation.
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Displaying 1 - 16 of 16 reviews
January 10, 2024
I don't know what made me buy this but I'm glad that I did and glad that I've read it. Chemistry is a subject that leaves many people absolutely cold...or frightened. Maybe it's because of the way it's taught at schools or the teachers who purport to teach. Certainly, in the case of my children they were put off the subject by their teachers. And, maybe, it should be taught more along the lines of this book, which I found fascinating. It's written by a Nobel laureate in chemistry who looks at the world of chemistry from the perspective of synthesising molecules and deriving structures. Along the way he discusses isomerism, analytical chemistry, structure of molecules and ways of deriving structures and synthesising them. He finishes up with some philosophical ruminations on the role of chemists in society. Here are some of the take-aways that I had from the book:
"....nature is a tinkerer; the solutions for ensuring survival of a plant or animal are the result of millions of years of random experimentation. The patches on the fabric of life come in a bewildering variety of molecular shapes and colors. Anything that works is co-opted. And banged into shape by all those natural experiments.?
So the realistic question becomes not "What is it?" but "How much is there of what?" One must separate a substance into its constituent components. Each component is a compound, a persistent grouping of atoms that stick together. That group of atoms is called a molecule;.... After separation of a substance into its components, one wants to identify the constituent compounds. To a chemist, structure means the identity of the atoms that are in the pure compound, how those atoms are connected to each other, and what their arrangement in space is..... Illustration 2.2 is the outcome of such a machine at work. This "gas chromatograph" may cost about $5,000. It separates molecules by a repeated process of adsorbing them on little sandlike grains, then releasing them. In this duality of holding on and letting go, different molecules find a different balance and pass through the machine slower or faster".
"The psychology of finding solutions [in terms of analysis] involves a certain mental "drawing of a line," a self-imposed limit on how deep you need to go in. The people who go deeper and deeper are seeking another kind of knowledge than those who want to solve the problem......This brings us to reductionism and ways of understanding. By reductionism I mean the idea that there is a hierarchy of sciences, with an associated definition of understanding and an implied value judgment about the quality of that understanding. That hierarchy goes from the humanities, through the social sciences to biology, to chemistry, physics, and mathematics".
"By further refining, a minute amount of active material [of cockroach sex attractant] was obtained and a structure was proposed on the basis of physical measurements (illustration 5.2).... Within 3 years, six approaches were reported, all most ingenious. Two of them were successful, the others were honourable near misses. So the molecule was well and truly synthesized and the compound became readily available. There was only one snag—the proposed structure was wrong and the synthetic material inactive. A lady I know remarked at the time that, although this molecule wasn't very good at attracting male cockroaches, it certainly attracted a lot of organic chemists....."
Very soon one finds that the rules of the game (very simple-each carbon can form four bonds, each hydrogen one) allow two or more molecules made up of the same atoms, containing the same number and type of bonds, to exist. Thus for CH4H10 we have n-butane and isobutane..... Each has three C-C bonds and ten C-H bonds. Yet they are different; not very different, mind you, but different enough —in their volatility, in the heat generated when these petroleum constituents burn—to matter.....The phenomenon is called isomerism, its elucidation a triumph of nineteenth-century chemistry. Structural isomerism is not the only type of isomerism one has.....There is also geometrical isomerism, exemplified by the two ethylenes substituted by two bromines, as shown in illustration 7.6. Note that in both C,H,Br, isomers the atoms are connected up in the same way, but that there is a difference in geometry-in one case the two bromines are next to each other, in the other case they are opposite.
In the visual system, in the cones and rods of our retina, the energy of the light causes a transformation of one geometrical isomer of a molecule called retinal into another. The change is not that different in its essence from that illustrated for dibromoethylene. A nerve impulse is triggered, and eventually the molecule returns to the original geometry, ready for the next photon.
"......for hydrogen there are three isotopes: normal hydrogen (one electron moving around a nucleus made up of a single proton); "heavy" hydrogen or deuterium (one electron around a nucleus containing one proton and one neutron), and tritium (one electron still, but now a nucleus with one proton, two neutrons). In the official nomenclature of isotopes, the total number of protons and neutrons together is given as a superscript preceding the symbol for the element."......This is why the molecules made of elements that exist in a mixture of isotopes are a wonderful example of the same and not the same.......The isotopic modifications of a molecule are different enough so that we can tell they are there (with an instrument costing a few kilodollars".
The evolutionary tinkering that led to hemoglobin apparently took place in the absence of much carbon monoxide. Then we, humankind, came along, and incomplete combustions occasioned by us and our tools (notably, the automobile engine) now may generate locally high levels of CO...which binds very well to the haemoglobin molecule...much better than oxygen ...and so the organism can be starved of oxygen.
The molecule vibrates; it does not have a static structure. Another chemist comes and says: "You've just drawn the positions of the nuclei. But chemistry is in the electrons. You should draw out the chance of finding them at a certain place in space at a certain time-the electronic distribution." This is attempted in illustration 15.7. I could go on...
Some of the molecules are indeed there, just waiting to be known by us. "Known" in their static properties—what atoms are in them, how these are connected up, the shapes of molecules, their splendid colors....... But so many more molecules of chemistry are made by us, in the laboratory. We're awfully prolific—a registry of known, well-characterized compounds now numbers over ten million. Ten million compounds that were not on earth before!
"....uroporphyrino-gen-Ill (even in the trade, the name of this molecule is abbreviated as uro'gen-lIl). It isn't a glamorous molecule, but it should be. For from this precursor plants make chlorophyll, the basis of all photosynthetic activity. All cells use another uro'gen-Ill derivative in cytochromes for electron transport. And the crucial iron-containing oxygen carrier piece of hemoglobin derives from this small disk-shaped molecule...... How this natural molecule is assembled, within us, is clearly a discovery question...... This incredible but true story was deduced by Battersby and coworkers using a sequence of synthetic molecules, not natural ones." Each was designed to model some critical way station molecule in the living system...... The synthesis of molecules puts chemistry very close to the arts. We create the objects that we or others then study or appreciate..."
....There is high logic in synthetic strategy. The design of a multistep synthesis resembles the making of a chess problem. [In this example] ...at the end is cubane-the mating situation. [a molecule to be synthesised] In between are moves, with rules for making them. The rules are much more interesting and free than those of chess. The synthetic chemist's problem is to design a situation on the chessboard, ten moves back, which has the most ordinary appearance. But from that position, one player (or a team of chemists), by a clever sequence of moves, reaches the mating position no matter what the recalcitant opponent, the most formidable opponent of all, Nature, does.
The isotopic tracers of use in probing the mechanism of the ethane reaction were those of hydrogen, particularly deuterium, or "heavy" hydrogen. Okabe and McNesby took a mixture of normal ethane (CH,) and an ethane in which every last hydrogen was replaced with deuterium (C,D.). Where did they get the "deuterated" compound? They bought it, and back in the laboratories of Merck it was synthesized. What was the first thing they did after they got a sealed flask or ampoule of the gas from the chemical supplier? They probably analyzed it. In this business you do not trust anyone. [I really liked these informal practical details]
Let me restate, in colloquial language, what one might say from Popper's point of view about this beautiful experiment of Okabe and MeNesby: We have, in the weakness of our minds, written down three and only three hypotheses for how ethane might fragment under ultraviolet irradiation. And in the strength and beauty of our hands and our minds, we have constructed experiments to eliminate two such hypotheses. That does not prove the third one at all. There may be a fourth or a fifth one we just were not clever enough to devise......Now, everyone knows that. I know that, the people who did this experiment know that. But these are people who are doing experiments and interpreting them. It is in the nature of people not to want to write wishy-washy conclusions in papers, such as: I have disproven A and B. I hope it's C, but maybe it's something else." No, people want to say, "I have proven C." Scientists want to do something positive.
Note the enormous speed of these molecules; oxygen moves at close to the speed of sound (which is no accident-sound propagation depends on the molecular medium). The molecules don't get very far, however, before they collide with each other. The collision frequency and distance between collisions (called mean free path) do depend on the pressure and temperature of the gas. In outer space, the mean free path would be much, much greater (~10 to power of 9 kilometers in the intergalactic diffuse clouds; a friend remarks, "The poor chaps meet only every few hundred years")...... The average distance between O, molecules in our atmosphere is about 3.5 x 10-7 centimeters. This is about ten times the linear dimension of the molecule. One way to think about it is that the molecules through their rapid motions and collisions bang out an effective space around them that is substantially larger than the space they actually take up.
Enzymes are proteins, chains of amino acids. They are almost entirely made up of C, H, O, N, and S atoms. But often the active site of an enzyme uses essential metal atoms-among others, iron, copper, manganese, molybdenum, magnesium, zinc. Their importance in biological systems does not correlate with their abundance in the crust of the earth.
We eat (we need) proteins. Carboxypeptidase A is a protease, an enzyme that chops up protein by unhooking an amino acid from one end of the polypeptide chain. It specializes, as proteins do, in certain amino acids........ We are curious, we want to know how the enzyme works. To find that out, we certainly want to begin with the enzyme's structure. But we also want to know the shape of the intermediate ES. And ... that is like catching the wind. The enzyme is not called an enzyme for noth-ing— it catalyzes the relevant chemistry most efficiently. ES is there, but ever so fleetingly; the enzyme factory typically processes 100 million molecules a second. [ES is a "complex" of the enzyme with the protein to be degraded, the intermediate.].... In the end Lipscomb's beautiful work has led to a detailed mechanism for carboxypeptidase A's magic cleaving. This is shown in illustration 36.4. The bound enzyme complex (ES) is attacked (top of illustration) by a water molecule that is "activated" by a zine ion and a specific amino acid of the protein, glutamate 270....etc.,.....
About here, Hoffmann verges into philosophical/moral speculation: ......"Sandman points to "outrage factors," all the psychological components of risk perception. Let me choose some from among many he enumerates:......... Diffusion in time and space: Hazard A kills 50 anonymous people a year across the country. Hazard B has one chance in 10 of wiping out its neighborhood of 5,000 people sometime in the next decade. Risk assessment tells us the two have the same expected annual mortality: 50. "Outrage assessment" tells us A is probably acceptable and B is certainly not.
Friends, chemist friends, if someone comes before you verbalizing anxiety over a chemical in the environment, don't harden your hearts and assume a scientistic, analytical stance. Open your hearts, think of one of your children waking at night from a nightmare of being run over by a locomotive. Would you tell him (or her),....."Don't worry, the risk of you being bitten by a dog is greater"?
And his views on climate change ".... What we have added, mostly for the best of reasons, is in danger of modifying qualitatively the great cycles of the planet. The amount of nitrogen fixed from the atmosphere by the Haber-Bosch process, that masterpiece of chemical ingenuity, is, I suspect, comparable to global biological nitrogen fixation." These changes have been wrought in the geological equivalent of the blink of any eye. Gaia may have the restoring forces to deal with our transformations, but the world that results could be one in which humankind will not play a role".
I really liked the book. Five stars from me.
"....nature is a tinkerer; the solutions for ensuring survival of a plant or animal are the result of millions of years of random experimentation. The patches on the fabric of life come in a bewildering variety of molecular shapes and colors. Anything that works is co-opted. And banged into shape by all those natural experiments.?
So the realistic question becomes not "What is it?" but "How much is there of what?" One must separate a substance into its constituent components. Each component is a compound, a persistent grouping of atoms that stick together. That group of atoms is called a molecule;.... After separation of a substance into its components, one wants to identify the constituent compounds. To a chemist, structure means the identity of the atoms that are in the pure compound, how those atoms are connected to each other, and what their arrangement in space is..... Illustration 2.2 is the outcome of such a machine at work. This "gas chromatograph" may cost about $5,000. It separates molecules by a repeated process of adsorbing them on little sandlike grains, then releasing them. In this duality of holding on and letting go, different molecules find a different balance and pass through the machine slower or faster".
"The psychology of finding solutions [in terms of analysis] involves a certain mental "drawing of a line," a self-imposed limit on how deep you need to go in. The people who go deeper and deeper are seeking another kind of knowledge than those who want to solve the problem......This brings us to reductionism and ways of understanding. By reductionism I mean the idea that there is a hierarchy of sciences, with an associated definition of understanding and an implied value judgment about the quality of that understanding. That hierarchy goes from the humanities, through the social sciences to biology, to chemistry, physics, and mathematics".
"By further refining, a minute amount of active material [of cockroach sex attractant] was obtained and a structure was proposed on the basis of physical measurements (illustration 5.2).... Within 3 years, six approaches were reported, all most ingenious. Two of them were successful, the others were honourable near misses. So the molecule was well and truly synthesized and the compound became readily available. There was only one snag—the proposed structure was wrong and the synthetic material inactive. A lady I know remarked at the time that, although this molecule wasn't very good at attracting male cockroaches, it certainly attracted a lot of organic chemists....."
Very soon one finds that the rules of the game (very simple-each carbon can form four bonds, each hydrogen one) allow two or more molecules made up of the same atoms, containing the same number and type of bonds, to exist. Thus for CH4H10 we have n-butane and isobutane..... Each has three C-C bonds and ten C-H bonds. Yet they are different; not very different, mind you, but different enough —in their volatility, in the heat generated when these petroleum constituents burn—to matter.....The phenomenon is called isomerism, its elucidation a triumph of nineteenth-century chemistry. Structural isomerism is not the only type of isomerism one has.....There is also geometrical isomerism, exemplified by the two ethylenes substituted by two bromines, as shown in illustration 7.6. Note that in both C,H,Br, isomers the atoms are connected up in the same way, but that there is a difference in geometry-in one case the two bromines are next to each other, in the other case they are opposite.
In the visual system, in the cones and rods of our retina, the energy of the light causes a transformation of one geometrical isomer of a molecule called retinal into another. The change is not that different in its essence from that illustrated for dibromoethylene. A nerve impulse is triggered, and eventually the molecule returns to the original geometry, ready for the next photon.
"......for hydrogen there are three isotopes: normal hydrogen (one electron moving around a nucleus made up of a single proton); "heavy" hydrogen or deuterium (one electron around a nucleus containing one proton and one neutron), and tritium (one electron still, but now a nucleus with one proton, two neutrons). In the official nomenclature of isotopes, the total number of protons and neutrons together is given as a superscript preceding the symbol for the element."......This is why the molecules made of elements that exist in a mixture of isotopes are a wonderful example of the same and not the same.......The isotopic modifications of a molecule are different enough so that we can tell they are there (with an instrument costing a few kilodollars".
The evolutionary tinkering that led to hemoglobin apparently took place in the absence of much carbon monoxide. Then we, humankind, came along, and incomplete combustions occasioned by us and our tools (notably, the automobile engine) now may generate locally high levels of CO...which binds very well to the haemoglobin molecule...much better than oxygen ...and so the organism can be starved of oxygen.
The molecule vibrates; it does not have a static structure. Another chemist comes and says: "You've just drawn the positions of the nuclei. But chemistry is in the electrons. You should draw out the chance of finding them at a certain place in space at a certain time-the electronic distribution." This is attempted in illustration 15.7. I could go on...
Some of the molecules are indeed there, just waiting to be known by us. "Known" in their static properties—what atoms are in them, how these are connected up, the shapes of molecules, their splendid colors....... But so many more molecules of chemistry are made by us, in the laboratory. We're awfully prolific—a registry of known, well-characterized compounds now numbers over ten million. Ten million compounds that were not on earth before!
"....uroporphyrino-gen-Ill (even in the trade, the name of this molecule is abbreviated as uro'gen-lIl). It isn't a glamorous molecule, but it should be. For from this precursor plants make chlorophyll, the basis of all photosynthetic activity. All cells use another uro'gen-Ill derivative in cytochromes for electron transport. And the crucial iron-containing oxygen carrier piece of hemoglobin derives from this small disk-shaped molecule...... How this natural molecule is assembled, within us, is clearly a discovery question...... This incredible but true story was deduced by Battersby and coworkers using a sequence of synthetic molecules, not natural ones." Each was designed to model some critical way station molecule in the living system...... The synthesis of molecules puts chemistry very close to the arts. We create the objects that we or others then study or appreciate..."
....There is high logic in synthetic strategy. The design of a multistep synthesis resembles the making of a chess problem. [In this example] ...at the end is cubane-the mating situation. [a molecule to be synthesised] In between are moves, with rules for making them. The rules are much more interesting and free than those of chess. The synthetic chemist's problem is to design a situation on the chessboard, ten moves back, which has the most ordinary appearance. But from that position, one player (or a team of chemists), by a clever sequence of moves, reaches the mating position no matter what the recalcitant opponent, the most formidable opponent of all, Nature, does.
The isotopic tracers of use in probing the mechanism of the ethane reaction were those of hydrogen, particularly deuterium, or "heavy" hydrogen. Okabe and McNesby took a mixture of normal ethane (CH,) and an ethane in which every last hydrogen was replaced with deuterium (C,D.). Where did they get the "deuterated" compound? They bought it, and back in the laboratories of Merck it was synthesized. What was the first thing they did after they got a sealed flask or ampoule of the gas from the chemical supplier? They probably analyzed it. In this business you do not trust anyone. [I really liked these informal practical details]
Let me restate, in colloquial language, what one might say from Popper's point of view about this beautiful experiment of Okabe and MeNesby: We have, in the weakness of our minds, written down three and only three hypotheses for how ethane might fragment under ultraviolet irradiation. And in the strength and beauty of our hands and our minds, we have constructed experiments to eliminate two such hypotheses. That does not prove the third one at all. There may be a fourth or a fifth one we just were not clever enough to devise......Now, everyone knows that. I know that, the people who did this experiment know that. But these are people who are doing experiments and interpreting them. It is in the nature of people not to want to write wishy-washy conclusions in papers, such as: I have disproven A and B. I hope it's C, but maybe it's something else." No, people want to say, "I have proven C." Scientists want to do something positive.
Note the enormous speed of these molecules; oxygen moves at close to the speed of sound (which is no accident-sound propagation depends on the molecular medium). The molecules don't get very far, however, before they collide with each other. The collision frequency and distance between collisions (called mean free path) do depend on the pressure and temperature of the gas. In outer space, the mean free path would be much, much greater (~10 to power of 9 kilometers in the intergalactic diffuse clouds; a friend remarks, "The poor chaps meet only every few hundred years")...... The average distance between O, molecules in our atmosphere is about 3.5 x 10-7 centimeters. This is about ten times the linear dimension of the molecule. One way to think about it is that the molecules through their rapid motions and collisions bang out an effective space around them that is substantially larger than the space they actually take up.
Enzymes are proteins, chains of amino acids. They are almost entirely made up of C, H, O, N, and S atoms. But often the active site of an enzyme uses essential metal atoms-among others, iron, copper, manganese, molybdenum, magnesium, zinc. Their importance in biological systems does not correlate with their abundance in the crust of the earth.
We eat (we need) proteins. Carboxypeptidase A is a protease, an enzyme that chops up protein by unhooking an amino acid from one end of the polypeptide chain. It specializes, as proteins do, in certain amino acids........ We are curious, we want to know how the enzyme works. To find that out, we certainly want to begin with the enzyme's structure. But we also want to know the shape of the intermediate ES. And ... that is like catching the wind. The enzyme is not called an enzyme for noth-ing— it catalyzes the relevant chemistry most efficiently. ES is there, but ever so fleetingly; the enzyme factory typically processes 100 million molecules a second. [ES is a "complex" of the enzyme with the protein to be degraded, the intermediate.].... In the end Lipscomb's beautiful work has led to a detailed mechanism for carboxypeptidase A's magic cleaving. This is shown in illustration 36.4. The bound enzyme complex (ES) is attacked (top of illustration) by a water molecule that is "activated" by a zine ion and a specific amino acid of the protein, glutamate 270....etc.,.....
About here, Hoffmann verges into philosophical/moral speculation: ......"Sandman points to "outrage factors," all the psychological components of risk perception. Let me choose some from among many he enumerates:......... Diffusion in time and space: Hazard A kills 50 anonymous people a year across the country. Hazard B has one chance in 10 of wiping out its neighborhood of 5,000 people sometime in the next decade. Risk assessment tells us the two have the same expected annual mortality: 50. "Outrage assessment" tells us A is probably acceptable and B is certainly not.
Friends, chemist friends, if someone comes before you verbalizing anxiety over a chemical in the environment, don't harden your hearts and assume a scientistic, analytical stance. Open your hearts, think of one of your children waking at night from a nightmare of being run over by a locomotive. Would you tell him (or her),....."Don't worry, the risk of you being bitten by a dog is greater"?
And his views on climate change ".... What we have added, mostly for the best of reasons, is in danger of modifying qualitatively the great cycles of the planet. The amount of nitrogen fixed from the atmosphere by the Haber-Bosch process, that masterpiece of chemical ingenuity, is, I suspect, comparable to global biological nitrogen fixation." These changes have been wrought in the geological equivalent of the blink of any eye. Gaia may have the restoring forces to deal with our transformations, but the world that results could be one in which humankind will not play a role".
I really liked the book. Five stars from me.
June 5, 2018
Uma boa descrição de toda a beleza da química. Vale MUITO a pena.
April 28, 2021
Enjoyed the book thoroughly.
November 21, 2021
化學的部分很有趣，但其實佔的篇幅不多，感覺像是哲學的書而不是化學咧。
March 3, 2022
La edición es español del FCE es una basura, muy incomodo de leer la mayoría del tiempo, no me encantó
May 5, 2024
Bello nea larte di descrizione tecnica ma un po' noioso nella parte finale più politica e filosofica
April 25, 2025
Very interesting at times, incomprehensible for the chemistry layman at others.
April 23, 2024
*memo
제1부 정체 - 핵심문제
기체 크로마토그래피
X-선회절기
NMR 핵자기 공명 -> 분자에 들어 있는 수소 원자의 자기장 세기 측정
화학에서 사용되는 어떤 개념이 물리학분야로 한원될 수 없는 경우도 있다. 그런 경우에 억지로 환원시키면 처음의 매력이 거의 모두 사라지게 된다. 화학에서의 일반적인 개념인 방향성, 산성도와 염기도, 작용기, 치환기 효과 등이 바로 그런 예가 된다. (39p)
comment: 더 많은 것을 알게 된다면 결국 한원되지 않을까. 화학과 물리 사이의 단절
그래도 흥미로운 관점. 학문 간 현실적인 관계로는 공감
? -> 모델 생물 강연할 때 물어볼걸.
실험 목적에 적합한 모델 생물은 어떻게 찾는지? 다양한 생물을 다 알 수 없을텐데.
이성질현상 구조이성질체 (메탄계 탄화수소), 기하이성질체
레티날 기하이성질체 변환 -> 신경펄스 -> 뇌 -> 레티날 기하이성질체 변환
-> 레티날 분자 회복
트랜스지방, 트랜스 불포화 지방? 포화지방, 불포화지방?
큰 분자의 경우에는 버마고양이의 몸 전체에서도 똑같은 분자를 2개 이상 찾을 수는 없다. (58p)
-> 동위원소 때문
광학회전..? 화합물 중에는 편광면을 회전시키는 물질이 있다. (61p)
-> 설탕. 공돌이 용달 실험.
프랑스 과학자들은 겉모습이 서로 거울상에 해당하는 두 개의 수정 결정이 편광면을 서로 반대 방향으로 회전시킨다는 사실을 발견했다. (61p) -> 탄소 원자 사면체형이기 때문.
comment: 헐 신기하다 이렇게 연결이 되는구나
같기도 하지만 다르기도 하다.(69p)
comment: 제목이 이성질체 말하는 거였구나.
광학분리는 왼손성과 오른손성 분자의 혼합물에 키랄성 분자를 넣어주었을 때 물리학적으로 명백하게 구별되는 두 가지 화합물이 만들어지는 반응을 사용한다. (66p)
화학적 속임수
1) 일산화탄소(헤모글조빈. 산소)
2) 에틸렌 글리콜 (에탄올)
3) 술파제(엽산): 연쇄상구균성 감염에 효과
1) d-투보쿠라린 (쿠라레, 아세틸콜린)
제2부 화학의 표현방법
화학논문-> 억제된 긴박감. 실제 사실 보고.. 비현실적.
comment: 교과서에서 과학적 사실만을 배우다 이 사실이 밝혀진 배경을 알고 왜 이걸 몰랐을까 아쉬웠다. 논문작성도 같은 맥락이 아닐까.
언어학적구조 = 분자 및 분자의 변환. 흥미롭다.
분자구로 속기식 -> 탄소의 골격만
3차원 표현. 공막대기 모형 공간 채움 모형. 조화운동. 전자분포 -> 비유.
잘못된 절대 배열?
주사 터널 현미경법.
이론 화학자, 실험 화학자 구분이 되는 구나.
경제활동 관련, 특허권은 연구 결과 공개에 걸림돌
익명의 심사과장 - <생물과 미생물 사이> <이중나선> 논문심사과정.
논문에 감정이 노출되지 않도록 노력. 앞으로 논문 볼 때 유의해서 읽으면 재밌겠다.
제3부 분자의 합성
화학 -> 발전보다 창조, 통합. 창조로서의 과학. 근사와 복잡성 사이의 균형. 발견으로서의 예술.
화학 합성
1) 단순합성(열 + a)
2) 계획과 우연에 의한 합성
3) 산업에 의한 합성
comment: 자연적인 것을 선호? 우리나라는 양치 후 입 8번 이상 헹굼. 케미컬 포비아 현상.
가습기 살균제 사건. 의학 연관 추가 조사?
원유 -> 벤진 -> … -> 아세트산
comment: 진짜 석유 고갈나면 큰일나겠다. 다 석유야.
화학 합성은 명백한 건축 과정이다. (150p) -> 큐반. 받침에 필요. 보호기의 기법. 진짜 재밌다.
주변의 무질시도를 증가시킴으로써 부분적인 질서를 창조하게 된다. (152p)
미학적 과학적 분석 -> 자연적인 것, 인공적인 것 구분은 혼돈스러운 것.
제4부 뭔가 잘못될 때
탈리도마이드 -> 화학자. 의사.. 윤리.
아주 작은 차이 -> 극단적으로 다른 결과
세상에 나쁜 분자란 없고 다만 부주의함이 있을 뿐이며, (196p)
제 5부 도대체 어떻게 일어날까?
29. 메커니즘
comment: 과학철학에 대한 생각을 바꾸었다.
과학철학자들의 놀쟁이 소오적인 측면이 강하다고 생각했으나 과학철학이 더 발달했다면 지연과학도 다른 방향으로 발전했을 것.
기체의 속력 분포 측정 장치(221p) 기깔난다
N2 + 3H2 <-> 2MH3
화학 평형에 관계되는 조건들을 완전히 이해함으로써 가능한 일 (233p)
1) 암모니아 즉시 꺼낸다
2) 온도 변화
3) 압력 변화
4) 촉매 이용 (오스뮴. 우라늄)
제6부 화학에서의 삶
33. 프리스하버
1차 세계대전 후 추일에 엄청난 배상금이 부과되었고, 하버는 바닷물에서 금 추출하는 방법 개발 시작. 마음이 복잡하다. 이후 히틀러 집권. 불행한 사람 그리고 무책임한 사람.
제7부 확실한 마술.
촉매. 예) 효소
A + X <-> AX
AX + B <-> C + D + X
효소가 쉽게 휘어진다. (구조 재조정)
여기서 내가 주장하고 싶은 것은 화학을 비롯한 과학이 어쩔 수 없이 사회의 민주화에 기여해왔다는 것이다. (290p)
comment: <원령공주> 생각남. 파푸아뉴기니 마녀사냥. 문명이 발전되어야할 이유.
vs <엔트로피> 세계대전. 식민지 쟁탈전. 홀로코스트 핵무기
우리 본성의 선한 천사: 시간이 흐를수록 폭력성이 감소한다
휴먼카인드: 시간이 흐를수록 폭력성이 증가했다가 현대에 이르러 감소한다
우리가 살고 있는 세상은 단순한 과학적 분석으로는 이해할 수 없다. (301p)
그들의 사회주의는 인간이 자연을 변화시킨 것처럼 사회도 변환시킬 능력을 가지고 있다는 생각과, 사회는 무한히 발전할 수 있을 것이라는 미신에 그 근거를 두고 있다. (303p)
화학 공부를 해야하는 이유
1. 주변세상을 모르면 소외된다. 세상을 이해하지 못하면 비합리적인 생각을 하게 된다.
2. 민주주의를 위해서. 유전공학, 폐기물 처리장, 공장, 습관성 약물 등 시민이 결정해야한다.
과학을 공부해야 한다. 비합리적인 과학에 대한 공포 등
제10부 생동하는 이원성
관찰/간섭
원자보다 작은 수준에서의 관찰은 간섭을 의미한다. (337p) -> 하이젠베르크 불확정성의 원리
순수/불순 -> 헤겔의 변증법, 주제와 반주제의 경쟁으로부터 조화
우리의 모든 경험은 우리 자신이 모순 덩어리일 뿐만 아니라 모순이 없다면 아무것도 존재할 수 없다. (344p)
comment: 경계. 아와 비아 사이
우리의 정신은 유전과 경험과 우연에 의해서 만들어진 신경세포들의 가지 달린 나무가 아니라 완전히 서로 연결된 다차원의 공간이라고 생각하고 싶다. (349p)
분자에게 제기하는 의문은 우리 자신도 모르는 사이에 우리 자신에게 제기해야만 할 핵심적인 질문을 소리없이 건드리게 된다. (350p)
인간이면서 괴수이다.
온전한 인간도 아니었고, 온전한 괴수도 아니었다.
정적이면서 빠르게 움직이고 긴박하며, 복잡하면서도 통합된 존재였다.
해칠 능력이 있으면서도 선을 추구한 존재였다.
마치 화학과 같이. (355p)
제1부 정체 - 핵심문제
기체 크로마토그래피
X-선회절기
NMR 핵자기 공명 -> 분자에 들어 있는 수소 원자의 자기장 세기 측정
화학에서 사용되는 어떤 개념이 물리학분야로 한원될 수 없는 경우도 있다. 그런 경우에 억지로 환원시키면 처음의 매력이 거의 모두 사라지게 된다. 화학에서의 일반적인 개념인 방향성, 산성도와 염기도, 작용기, 치환기 효과 등이 바로 그런 예가 된다. (39p)
comment: 더 많은 것을 알게 된다면 결국 한원되지 않을까. 화학과 물리 사이의 단절
그래도 흥미로운 관점. 학문 간 현실적인 관계로는 공감
? -> 모델 생물 강연할 때 물어볼걸.
실험 목적에 적합한 모델 생물은 어떻게 찾는지? 다양한 생물을 다 알 수 없을텐데.
이성질현상 구조이성질체 (메탄계 탄화수소), 기하이성질체
레티날 기하이성질체 변환 -> 신경펄스 -> 뇌 -> 레티날 기하이성질체 변환
-> 레티날 분자 회복
트랜스지방, 트랜스 불포화 지방? 포화지방, 불포화지방?
큰 분자의 경우에는 버마고양이의 몸 전체에서도 똑같은 분자를 2개 이상 찾을 수는 없다. (58p)
-> 동위원소 때문
광학회전..? 화합물 중에는 편광면을 회전시키는 물질이 있다. (61p)
-> 설탕. 공돌이 용달 실험.
프랑스 과학자들은 겉모습이 서로 거울상에 해당하는 두 개의 수정 결정이 편광면을 서로 반대 방향으로 회전시킨다는 사실을 발견했다. (61p) -> 탄소 원자 사면체형이기 때문.
comment: 헐 신기하다 이렇게 연결이 되는구나
같기도 하지만 다르기도 하다.(69p)
comment: 제목이 이성질체 말하는 거였구나.
광학분리는 왼손성과 오른손성 분자의 혼합물에 키랄성 분자를 넣어주었을 때 물리학적으로 명백하게 구별되는 두 가지 화합물이 만들어지는 반응을 사용한다. (66p)
화학적 속임수
1) 일산화탄소(헤모글조빈. 산소)
2) 에틸렌 글리콜 (에탄올)
3) 술파제(엽산): 연쇄상구균성 감염에 효과
1) d-투보쿠라린 (쿠라레, 아세틸콜린)
제2부 화학의 표현방법
화학논문-> 억제된 긴박감. 실제 사실 보고.. 비현실적.
comment: 교과서에서 과학적 사실만을 배우다 이 사실이 밝혀진 배경을 알고 왜 이걸 몰랐을까 아쉬웠다. 논문작성도 같은 맥락이 아닐까.
언어학적구조 = 분자 및 분자의 변환. 흥미롭다.
분자구로 속기식 -> 탄소의 골격만
3차원 표현. 공막대기 모형 공간 채움 모형. 조화운동. 전자분포 -> 비유.
잘못된 절대 배열?
주사 터널 현미경법.
이론 화학자, 실험 화학자 구분이 되는 구나.
경제활동 관련, 특허권은 연구 결과 공개에 걸림돌
익명의 심사과장 - <생물과 미생물 사이> <이중나선> 논문심사과정.
논문에 감정이 노출되지 않도록 노력. 앞으로 논문 볼 때 유의해서 읽으면 재밌겠다.
제3부 분자의 합성
화학 -> 발전보다 창조, 통합. 창조로서의 과학. 근사와 복잡성 사이의 균형. 발견으로서의 예술.
화학 합성
1) 단순합성(열 + a)
2) 계획과 우연에 의한 합성
3) 산업에 의한 합성
comment: 자연적인 것을 선호? 우리나라는 양치 후 입 8번 이상 헹굼. 케미컬 포비아 현상.
가습기 살균제 사건. 의학 연관 추가 조사?
원유 -> 벤진 -> … -> 아세트산
comment: 진짜 석유 고갈나면 큰일나겠다. 다 석유야.
화학 합성은 명백한 건축 과정이다. (150p) -> 큐반. 받침에 필요. 보호기의 기법. 진짜 재밌다.
주변의 무질시도를 증가시킴으로써 부분적인 질서를 창조하게 된다. (152p)
미학적 과학적 분석 -> 자연적인 것, 인공적인 것 구분은 혼돈스러운 것.
제4부 뭔가 잘못될 때
탈리도마이드 -> 화학자. 의사.. 윤리.
아주 작은 차이 -> 극단적으로 다른 결과
세상에 나쁜 분자란 없고 다만 부주의함이 있을 뿐이며, (196p)
제 5부 도대체 어떻게 일어날까?
29. 메커니즘
comment: 과학철학에 대한 생각을 바꾸었다.
과학철학자들의 놀쟁이 소오적인 측면이 강하다고 생각했으나 과학철학이 더 발달했다면 지연과학도 다른 방향으로 발전했을 것.
기체의 속력 분포 측정 장치(221p) 기깔난다
N2 + 3H2 <-> 2MH3
화학 평형에 관계되는 조건들을 완전히 이해함으로써 가능한 일 (233p)
1) 암모니아 즉시 꺼낸다
2) 온도 변화
3) 압력 변화
4) 촉매 이용 (오스뮴. 우라늄)
제6부 화학에서의 삶
33. 프리스하버
1차 세계대전 후 추일에 엄청난 배상금이 부과되었고, 하버는 바닷물에서 금 추출하는 방법 개발 시작. 마음이 복잡하다. 이후 히틀러 집권. 불행한 사람 그리고 무책임한 사람.
제7부 확실한 마술.
촉매. 예) 효소
A + X <-> AX
AX + B <-> C + D + X
효소가 쉽게 휘어진다. (구조 재조정)
여기서 내가 주장하고 싶은 것은 화학을 비롯한 과학이 어쩔 수 없이 사회의 민주화에 기여해왔다는 것이다. (290p)
comment: <원령공주> 생각남. 파푸아뉴기니 마녀사냥. 문명이 발전되어야할 이유.
vs <엔트로피> 세계대전. 식민지 쟁탈전. 홀로코스트 핵무기
우리 본성의 선한 천사: 시간이 흐를수록 폭력성이 감소한다
휴먼카인드: 시간이 흐를수록 폭력성이 증가했다가 현대에 이르러 감소한다
우리가 살고 있는 세상은 단순한 과학적 분석으로는 이해할 수 없다. (301p)
그들의 사회주의는 인간이 자연을 변화시킨 것처럼 사회도 변환시킬 능력을 가지고 있다는 생각과, 사회는 무한히 발전할 수 있을 것이라는 미신에 그 근거를 두고 있다. (303p)
화학 공부를 해야하는 이유
1. 주변세상을 모르면 소외된다. 세상을 이해하지 못하면 비합리적인 생각을 하게 된다.
2. 민주주의를 위해서. 유전공학, 폐기물 처리장, 공장, 습관성 약물 등 시민이 결정해야한다.
과학을 공부해야 한다. 비합리적인 과학에 대한 공포 등
제10부 생동하는 이원성
관찰/간섭
원자보다 작은 수준에서의 관찰은 간섭을 의미한다. (337p) -> 하이젠베르크 불확정성의 원리
순수/불순 -> 헤겔의 변증법, 주제와 반주제의 경쟁으로부터 조화
우리의 모든 경험은 우리 자신이 모순 덩어리일 뿐만 아니라 모순이 없다면 아무것도 존재할 수 없다. (344p)
comment: 경계. 아와 비아 사이
우리의 정신은 유전과 경험과 우연에 의해서 만들어진 신경세포들의 가지 달린 나무가 아니라 완전히 서로 연결된 다차원의 공간이라고 생각하고 싶다. (349p)
분자에게 제기하는 의문은 우리 자신도 모르는 사이에 우리 자신에게 제기해야만 할 핵심적인 질문을 소리없이 건드리게 된다. (350p)
인간이면서 괴수이다.
온전한 인간도 아니었고, 온전한 괴수도 아니었다.
정적이면서 빠르게 움직이고 긴박하며, 복잡하면서도 통합된 존재였다.
해칠 능력이 있으면서도 선을 추구한 존재였다.
마치 화학과 같이. (355p)
July 1, 2016
Just some passages/quotes:
"Scientists have bought the reductionist mode of thinking as their guiding ideology. Yet this philosophy bears so little relationship to the reality within which scientists themselves operate. And it carries potential danger to the discourse of scientists with the rest of society.
I think the reality of understanding is the following: Every field of human knowledge or art develops its own complexity of questions... Much of what people call understanding is a discussion of questions in the context of the complexity or hierarchy or concepts which are developed within that field. If you wanted to deprecate this way of thinking, you would call it quasi-circular. I wouldn't deprecate it; I think this kind of understanding is quintessentially human and has led to great art and science.
There are vertical and horizontal ways of understanding. The vertical way is by reducing a phenomena to something deeper--classical reductionism. The horizontal way is by analyzing the phenomena within its own discipline and seeing its relationships to other concepts of equal complexity." 19
"The duality of benefit and potential harm is faced by real, fallible, ethical human beings in the context of any object in their environment." 199
"My second point of concern about chemical illiteracy returns me to democracy. Ignorance of chemistry poses a barrier to the democratic process. I believe deeply, as must be clear now, that "ordinary people" must be empowered to make decisions--on genetic engineering or on waste disposal sites, on dangerous and safe factories or on which addictive drugs should or should not be controlled. Citizens can call on experts to explain the advantages and disadvantages, the options, the benefits and risks. But experts do not have the mandate; the people and their representatives do. The people also have a responsibility--they need to learn enough chemistry to be able to resist the seductive words of, yes, chemical experts who can be assembled to support any nefarious activity you please." 228
"Scientists have bought the reductionist mode of thinking as their guiding ideology. Yet this philosophy bears so little relationship to the reality within which scientists themselves operate. And it carries potential danger to the discourse of scientists with the rest of society.
I think the reality of understanding is the following: Every field of human knowledge or art develops its own complexity of questions... Much of what people call understanding is a discussion of questions in the context of the complexity or hierarchy or concepts which are developed within that field. If you wanted to deprecate this way of thinking, you would call it quasi-circular. I wouldn't deprecate it; I think this kind of understanding is quintessentially human and has led to great art and science.
There are vertical and horizontal ways of understanding. The vertical way is by reducing a phenomena to something deeper--classical reductionism. The horizontal way is by analyzing the phenomena within its own discipline and seeing its relationships to other concepts of equal complexity." 19
"The duality of benefit and potential harm is faced by real, fallible, ethical human beings in the context of any object in their environment." 199
"My second point of concern about chemical illiteracy returns me to democracy. Ignorance of chemistry poses a barrier to the democratic process. I believe deeply, as must be clear now, that "ordinary people" must be empowered to make decisions--on genetic engineering or on waste disposal sites, on dangerous and safe factories or on which addictive drugs should or should not be controlled. Citizens can call on experts to explain the advantages and disadvantages, the options, the benefits and risks. But experts do not have the mandate; the people and their representatives do. The people also have a responsibility--they need to learn enough chemistry to be able to resist the seductive words of, yes, chemical experts who can be assembled to support any nefarious activity you please." 228
September 3, 2010
When I go to libraries, I tend to surf the shelves and grab any book that looks interesting. I usually don't end up reading anything I grab, but it's still fun. Anyways, I grabbed this book in one such moment and surprised myself by actually reading it. And I really enjoyed it - it was a fascinating look into chemistry, which is a lot more interesting than I remember from high school. Besides talking about how chemists approach things and some general ground rules for the molecular world Hoffman talks about everything in the light of the title, "The Same and not the Same". Basically, that chemistry is full of dualities, from the molecules to the way scientists study them and try to manipulate them, and even the way the public perceives chemists. Plus, it made me feel smart when people asked me, "What are you reading?" and I got the smug satisfaction of saying, "A chemistry book."
April 30, 2013
The ideas are beautiful and novel, and it was enjoyable to see chemistry talked about in a manner that many of the others sciences are but it is not, often: as a poetry and a conceptual pursuit, as well as a way to look at and a methodology with which to compute the world, but the execution is not as splendiferous. I would have enjoyed it even more if the author's handle of language were as good as his handle of lots of other things.
January 27, 2014
Though some of the heavy chemistry chapters went a bit over my head, I surprisingly enjoyed this book. It has a textbook quality to it, but also a novel quality to it. There was one particularly beautiful quote, "It is not 'us' (whoever 'us' is) versus 'them', those irrational, Luddite critics of our lifestyle. There is so much of 'them' in 'us' - allow for that life-enhancing and beautiful complexity of human beings..."
And look at that, we've related aspects of chemistry to all of life.
And look at that, we've related aspects of chemistry to all of life.
May 13, 2009
odd yet good book-- can't remember how came across it, but likely from Carbon Age references.
it's a collection of Hoffman's lectures (sort of)-- about chemistry, the nature of chemistry & it's place in the world. Odd mix of ideas & points-- appropriate from both a Nobel chemist & poet.
it's a collection of Hoffman's lectures (sort of)-- about chemistry, the nature of chemistry & it's place in the world. Odd mix of ideas & points-- appropriate from both a Nobel chemist & poet.
April 20, 2011
This book was recommended to me by my organic chemistry professor. Hoffmann writes about science in a very accessible and lucid way. The book focuses mostly on chemistry, which is no surprise, the author is a Nobel laureate in chemistry.
March 24, 2015
Excellent book - if I were to write a popular book about chemistry, I would want it to be half as good. Roald Hoffman has a unique perspective on chemistry, life, and everything. Highly recommended for any scientist (or non-scientist, for that matter).
June 20, 2008
An enlightening reflection on the art and science of chemistry. Equally recommendable to scientists and non-scientists.
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