Istvan Hargittai - Academia.edu (original) (raw)

Papers by Istvan Hargittai

Structural Chemistry, Oct 30, 2021

He received his degrees from Glasgow University, was at the ETH Zurich since 1957, and retired in... more He received his degrees from Glasgow University, was at the ETH Zurich since 1957, and retired in 1990. His research interests included crystal structure analysis as a tool for solving chemical problems, polymorphism, solid state reactions, and a broad area of structural variations during chemical events under the umbrella term of structure correlation.

The use of general descriptive names, registered names, trademarks, service marks, etc. in this p... more The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use.

Structural Chemistry, 2022

On April 8, 1982, Dan Shechtman conducted an electron diffraction experiment on an aluminum/manga... more On April 8, 1982, Dan Shechtman conducted an electron diffraction experiment on an aluminum/manganese alloy. The diffraction pattern showed tenfold symmetry although the rules of crystallography excluded such symmetry in extended structures. Alan L. Mackay had anticipated such structures, which fit his view of generalized crystallography. Shechtman persisted in claiming to have observed quasiperiodic structures despite denial of such structures even by Linus Pauling, the greatest authority in chemistry. When Shechtman's claim was finally accepted, he was amply awarded for his contribution, including his Nobel Prize in 2011. The theoretical physicists Paul J. Steinhardt and Dove Levine coined the name quasicrystals, and advanced the field greatly by their models, but appeared to downplay somewhat the significance of prior predictions and of the experimental discovery.

Structural Chemistry, 2021

Croatica Chemica Acta, 1996

A broad overview is presented about the importance of molecular structure determination and about... more A broad overview is presented about the importance of molecular structure determination and about the structural considerations that come in view when molecular units build assemblies. Structural chemistry and crystallography constitute an integral part of today's supramolecular chemistry as demonstrated by various statements of giants of the field. The challenge of supramolecular chemistry to the structural chemist is in detecting and understanding the structural changes accompanyingmolecular recognition and assembly formation and in providing assistance for the design of new assemblies and molecular devices with desired properties.

Structural Chemistry, 2021

Jack D. Dunitz (1923–2021) was Professor of Chemical Crystallography at the Swiss Federal Institu... more Jack D. Dunitz (1923–2021) was Professor of Chemical Crystallography at the Swiss Federal Institute of Technology, Zurich. He received his degrees from Glasgow University, was at the ETH Zurich since 1957, and retired in 1990. His research interests included crystal structure analysis as a tool for solving chemical problems, polymorphism, solid state reactions, and a broad area of structural variations during chemical events under the umbrella term of structure correlation.

Structural Chemistry, 2021

In 1962, the MRC Laboratory of Molecular Biology in Cambridge, UK, moved into a new building and ... more In 1962, the MRC Laboratory of Molecular Biology in Cambridge, UK, moved into a new building and continued a success story that had begun 15 before. Milestone discoveries and Nobel Prizes have followed ever since. They have led to profound changes in our basic ideas about the nature of life and the way medicine operates. Structural chemistry has paved the way for this unprecedented progress.

European Review, 2021

The world-renowned physicist Andrei D. Sakharov (1921–1989) was ‘the father of the Soviet hydroge... more The world-renowned physicist Andrei D. Sakharov (1921–1989) was ‘the father of the Soviet hydrogen bomb’ and, as such, an architect of the Soviet superpower. He developed into a fierce fighter for human rights, distinguished by the Nobel Peace Prize. In his words, ‘my fate was larger than what would have followed from my personality. I was merely trying to be worthy of my fate.’1 His life and career provide thought-provoking lessons and is worthy of review on the eve of his centennial.

Structural Chemistry, 2010

Torvard C. Laurent (1930-2009) was one of the pioneers of hyaluronan science and in particular of... more Torvard C. Laurent (1930-2009) was one of the pioneers of hyaluronan science and in particular of its structural aspects. He was the first who ever established the metrical characteristics of hyaluronan. He determined many of its physicochemical properties and their relationship to the versatile biological functions of this noted molecule. He also contributed to its medical applications. He was a leading personality in science administration and science policy in Sweden and internationally. Keywords Torvard C. Laurent Á Hyaluronan Á Macromolecular structures Á X-ray studies of amorphous bodies Á Structure and biological function I believe that a lot of the future of the biological function can be revealed by studies of protein-hyaluronan complexes. Torvard C. Laurent, 2003 [1] Torvard C. Laurent (Fig. 1) was born in 1930 in Stockholm into an academic family. Of his family's history, he especially revered his great-grandfather, Carl-Erik Bergstrand (1830-1914) who became Professor of Agricultural Chemistry in 1864 and taught at Ultuna, which was the predecessor of today's Swedish Agricultural University. In the period of 1869-1882, he was in charge of the Chemical Research Station of the Academy of Agricultural Sciences in Stockholm. His principal research area was in fertilizers. In order to expand his knowledge and gain experience, he visited German and Austrian laboratories in 1859 [2]. Laurent learned about his great-grandfather's life and activities from his diary. Laurent's aunt, Vivi Täckholm, was a professor of botany at Cairo University and was probably the best known among his relatives [3]. When Laurent was a teenager, he collected many plants for her in Fig. 1 Torvard C. Laurent in 2002 (photograph by Birgitta Hellsing; all photographs courtesy of the late Torvard C. Laurent and Agneta Laurent, Stockholm) This Editorial was being prepared simultaneously with a more detailed commemorative chapter, Hargittai I (2010) Torvard C Laurent, In Hargittai M, More conversations with hyaluronan scientists. Volume 2 in Balazs EA, General Editor, Hyaluronan: From Basic Science to Clinical Applications, PubMatrix, Edgewater, NJ (to be published).

Structural Chemistry, 2009

Structural Chemistry, 2009

Structural Chemistry, 2009

Linus Pauling, arguably the greatest chemist of the twentieth century, never publicly admitted th... more Linus Pauling, arguably the greatest chemist of the twentieth century, never publicly admitted that there was a race for the determination of the structure of the most important biopolymers. But according to his competitors there was a race, in fact, there were two, and Pauling won one and lost the other. He had a tremendous amount of ideas, many of them worthless, but a few were spectacular. Not only did he make seminal discoveries, he was also a master of announcing them in a most dramatic way. Eventually, Pauling shifted toward politics and controversial issues, but his science ensured him his place among the greats. Here, we follow Pauling's route to the discovery of the alpha-helix; the defeat of the star-studded British team in the same quest; and a seemingly unrelated story about the fate of the theory of resonance that assured Pauling's victory yet at the same time it was excommunicated in the Soviet Union.

Structural Chemistry, 2010

Geometry is an important ingredient in the chemical sciences and especially in structural chemist... more Geometry is an important ingredient in the chemical sciences and especially in structural chemistry. It is closely related to modeling, which is a favorite epistemological tool in chemistry. In the history of chemistry, simple geometrical models have often preceded sound experimental elucidation of structures. A series of examples are presented that include gas-phase electron diffraction; the origin of molecular mechanics; estimation of experimental error in quantum chemical computations; qualitative models of molecular structures; symmetrylowering effects; biological macromolecules; and chirality. Keywords Geometry Á Modeling Á Molecular mechanics Á Experimental error in computation Á Precision and accuracy Á Molecular packing Á Biomolecular structures Á Enantiomers Ubi material, ibi geometria.

Journal of Molecular Structure, 1984

Effets des substituants sur la geometrie du cycle benzenique determines par diffraction d'ele... more Effets des substituants sur la geometrie du cycle benzenique determines par diffraction d'electrons en phase gazeuse

European Review, 2005

Symmetry and chemistry have been in a fruitful interplay, initially in spectroscopy and crystallo... more Symmetry and chemistry have been in a fruitful interplay, initially in spectroscopy and crystallography, lately in more traditional domains of chemistry, such as reactivity and conformational analysis. A simple phenomenological approach suffices to get an idea about the symmetries of molecules whereas group theoretical approach greatly facilitates the understanding of molecular vibrations, electronic structure, and the mechanism of chemical reactions. In our discussion, the multi-level relationship between symmetry and chemistry is demonstrated by a sampler of examples, including the variations of symmetry of free molecules and molecular packing in crystals. Symmetry considerations continue to assist chemistry in systematizing and interpreting observations and also in discovering new reactions, molecules, and other materials.

Chemische Berichte, 1991

The molecular structure of 1,3-diphenylpropane-1,2,3-trione (diphenyl triketone) has been determi... more The molecular structure of 1,3-diphenylpropane-1,2,3-trione (diphenyl triketone) has been determined by gas-phase electron diffraction at 130°C nozzle temperature. It has been found that the phenyl rings are nearly coplanar with the adjacent carbonyl groups, and the two Cph–C(O)–C(O)–C(O) dihedral angles are - 129.5 ± 0.8 and - 107.1 ± 0.8° (0° corresponds to the syn form). Bond distances (rg, A) and bond angles (deg) with estimated total errors are CH 1.105 ± 0.006, O C 1.213 ± 0.003, 1.404± 0.003, Cph–C(O) 1.478 ± 0.005, C(O)–C(O) 1.558 ± 0.004, Cph–C(O)–C(O) 120.0 ± 0.3, CphC(O)O 120.8 ± 0.4, C(O)–C(O)–C(O) 117.3 ± 0.4, Cph–Cph(CO)–Cph 119.8 ± 0.6. Although there is a general agreement between the gas-phase and crystal molecular structures there are some notable differences. One of the benzene rings is slightly turned about the Cph–C(O) axis in the opposite direction in the gas molecule as compared to the crystal. This causes a marked shortening of the O… H intramolecular contact (to 2.18 A) between the central oxygen and an ortho-hydrogen.

Chemical Reviews, 2000

Figure 7. Lowest-energy structures for some polymeric forms of alkali halides. (a) (NaCl) n clust... more Figure 7. Lowest-energy structures for some polymeric forms of alkali halides. (a) (NaCl) n clusters for cluster sizes n) 2-10; binding energies in eV, decreasing from left to right. (Reprinted with permission from ref 55a. Copyright 1983 Elsevier Science.) (b) (LiF) n and (KCl) n clusters, for cluster sizes n) 3-8. The energy differences with respect to the most stable structures are given, in eV: first row refers to KCl, second row to LiF. (Reprinted with permission from ref 90.

Acta Crystallographica Section B Structural Science, 2008

Journal of Molecular Structure, 2001

Academia Molecular Biology and Genomics, Jun 10, 2024

This personal essay for the new publication Academia Molecular Biology and Genomics highlights so... more This personal essay for the new publication Academia Molecular Biology and Genomics highlights some developments in the early history of molecular biology.

Structural Chemistry, Oct 30, 2021

He received his degrees from Glasgow University, was at the ETH Zurich since 1957, and retired in... more He received his degrees from Glasgow University, was at the ETH Zurich since 1957, and retired in 1990. His research interests included crystal structure analysis as a tool for solving chemical problems, polymorphism, solid state reactions, and a broad area of structural variations during chemical events under the umbrella term of structure correlation.

The use of general descriptive names, registered names, trademarks, service marks, etc. in this p... more The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use.

Structural Chemistry, 2022

On April 8, 1982, Dan Shechtman conducted an electron diffraction experiment on an aluminum/manga... more On April 8, 1982, Dan Shechtman conducted an electron diffraction experiment on an aluminum/manganese alloy. The diffraction pattern showed tenfold symmetry although the rules of crystallography excluded such symmetry in extended structures. Alan L. Mackay had anticipated such structures, which fit his view of generalized crystallography. Shechtman persisted in claiming to have observed quasiperiodic structures despite denial of such structures even by Linus Pauling, the greatest authority in chemistry. When Shechtman's claim was finally accepted, he was amply awarded for his contribution, including his Nobel Prize in 2011. The theoretical physicists Paul J. Steinhardt and Dove Levine coined the name quasicrystals, and advanced the field greatly by their models, but appeared to downplay somewhat the significance of prior predictions and of the experimental discovery.

Structural Chemistry, 2021

Croatica Chemica Acta, 1996

A broad overview is presented about the importance of molecular structure determination and about... more A broad overview is presented about the importance of molecular structure determination and about the structural considerations that come in view when molecular units build assemblies. Structural chemistry and crystallography constitute an integral part of today's supramolecular chemistry as demonstrated by various statements of giants of the field. The challenge of supramolecular chemistry to the structural chemist is in detecting and understanding the structural changes accompanyingmolecular recognition and assembly formation and in providing assistance for the design of new assemblies and molecular devices with desired properties.

Structural Chemistry, 2021

Jack D. Dunitz (1923–2021) was Professor of Chemical Crystallography at the Swiss Federal Institu... more Jack D. Dunitz (1923–2021) was Professor of Chemical Crystallography at the Swiss Federal Institute of Technology, Zurich. He received his degrees from Glasgow University, was at the ETH Zurich since 1957, and retired in 1990. His research interests included crystal structure analysis as a tool for solving chemical problems, polymorphism, solid state reactions, and a broad area of structural variations during chemical events under the umbrella term of structure correlation.

Structural Chemistry, 2021

In 1962, the MRC Laboratory of Molecular Biology in Cambridge, UK, moved into a new building and ... more In 1962, the MRC Laboratory of Molecular Biology in Cambridge, UK, moved into a new building and continued a success story that had begun 15 before. Milestone discoveries and Nobel Prizes have followed ever since. They have led to profound changes in our basic ideas about the nature of life and the way medicine operates. Structural chemistry has paved the way for this unprecedented progress.

European Review, 2021

The world-renowned physicist Andrei D. Sakharov (1921–1989) was ‘the father of the Soviet hydroge... more The world-renowned physicist Andrei D. Sakharov (1921–1989) was ‘the father of the Soviet hydrogen bomb’ and, as such, an architect of the Soviet superpower. He developed into a fierce fighter for human rights, distinguished by the Nobel Peace Prize. In his words, ‘my fate was larger than what would have followed from my personality. I was merely trying to be worthy of my fate.’1 His life and career provide thought-provoking lessons and is worthy of review on the eve of his centennial.

Structural Chemistry, 2010

Torvard C. Laurent (1930-2009) was one of the pioneers of hyaluronan science and in particular of... more Torvard C. Laurent (1930-2009) was one of the pioneers of hyaluronan science and in particular of its structural aspects. He was the first who ever established the metrical characteristics of hyaluronan. He determined many of its physicochemical properties and their relationship to the versatile biological functions of this noted molecule. He also contributed to its medical applications. He was a leading personality in science administration and science policy in Sweden and internationally. Keywords Torvard C. Laurent Á Hyaluronan Á Macromolecular structures Á X-ray studies of amorphous bodies Á Structure and biological function I believe that a lot of the future of the biological function can be revealed by studies of protein-hyaluronan complexes. Torvard C. Laurent, 2003 [1] Torvard C. Laurent (Fig. 1) was born in 1930 in Stockholm into an academic family. Of his family's history, he especially revered his great-grandfather, Carl-Erik Bergstrand (1830-1914) who became Professor of Agricultural Chemistry in 1864 and taught at Ultuna, which was the predecessor of today's Swedish Agricultural University. In the period of 1869-1882, he was in charge of the Chemical Research Station of the Academy of Agricultural Sciences in Stockholm. His principal research area was in fertilizers. In order to expand his knowledge and gain experience, he visited German and Austrian laboratories in 1859 [2]. Laurent learned about his great-grandfather's life and activities from his diary. Laurent's aunt, Vivi Täckholm, was a professor of botany at Cairo University and was probably the best known among his relatives [3]. When Laurent was a teenager, he collected many plants for her in Fig. 1 Torvard C. Laurent in 2002 (photograph by Birgitta Hellsing; all photographs courtesy of the late Torvard C. Laurent and Agneta Laurent, Stockholm) This Editorial was being prepared simultaneously with a more detailed commemorative chapter, Hargittai I (2010) Torvard C Laurent, In Hargittai M, More conversations with hyaluronan scientists. Volume 2 in Balazs EA, General Editor, Hyaluronan: From Basic Science to Clinical Applications, PubMatrix, Edgewater, NJ (to be published).

Structural Chemistry, 2009

Structural Chemistry, 2009

Structural Chemistry, 2009

Linus Pauling, arguably the greatest chemist of the twentieth century, never publicly admitted th... more Linus Pauling, arguably the greatest chemist of the twentieth century, never publicly admitted that there was a race for the determination of the structure of the most important biopolymers. But according to his competitors there was a race, in fact, there were two, and Pauling won one and lost the other. He had a tremendous amount of ideas, many of them worthless, but a few were spectacular. Not only did he make seminal discoveries, he was also a master of announcing them in a most dramatic way. Eventually, Pauling shifted toward politics and controversial issues, but his science ensured him his place among the greats. Here, we follow Pauling's route to the discovery of the alpha-helix; the defeat of the star-studded British team in the same quest; and a seemingly unrelated story about the fate of the theory of resonance that assured Pauling's victory yet at the same time it was excommunicated in the Soviet Union.

Structural Chemistry, 2010

Geometry is an important ingredient in the chemical sciences and especially in structural chemist... more Geometry is an important ingredient in the chemical sciences and especially in structural chemistry. It is closely related to modeling, which is a favorite epistemological tool in chemistry. In the history of chemistry, simple geometrical models have often preceded sound experimental elucidation of structures. A series of examples are presented that include gas-phase electron diffraction; the origin of molecular mechanics; estimation of experimental error in quantum chemical computations; qualitative models of molecular structures; symmetrylowering effects; biological macromolecules; and chirality. Keywords Geometry Á Modeling Á Molecular mechanics Á Experimental error in computation Á Precision and accuracy Á Molecular packing Á Biomolecular structures Á Enantiomers Ubi material, ibi geometria.

Journal of Molecular Structure, 1984

Effets des substituants sur la geometrie du cycle benzenique determines par diffraction d'ele... more Effets des substituants sur la geometrie du cycle benzenique determines par diffraction d'electrons en phase gazeuse

European Review, 2005

Symmetry and chemistry have been in a fruitful interplay, initially in spectroscopy and crystallo... more Symmetry and chemistry have been in a fruitful interplay, initially in spectroscopy and crystallography, lately in more traditional domains of chemistry, such as reactivity and conformational analysis. A simple phenomenological approach suffices to get an idea about the symmetries of molecules whereas group theoretical approach greatly facilitates the understanding of molecular vibrations, electronic structure, and the mechanism of chemical reactions. In our discussion, the multi-level relationship between symmetry and chemistry is demonstrated by a sampler of examples, including the variations of symmetry of free molecules and molecular packing in crystals. Symmetry considerations continue to assist chemistry in systematizing and interpreting observations and also in discovering new reactions, molecules, and other materials.

Chemische Berichte, 1991

The molecular structure of 1,3-diphenylpropane-1,2,3-trione (diphenyl triketone) has been determi... more The molecular structure of 1,3-diphenylpropane-1,2,3-trione (diphenyl triketone) has been determined by gas-phase electron diffraction at 130°C nozzle temperature. It has been found that the phenyl rings are nearly coplanar with the adjacent carbonyl groups, and the two Cph–C(O)–C(O)–C(O) dihedral angles are - 129.5 ± 0.8 and - 107.1 ± 0.8° (0° corresponds to the syn form). Bond distances (rg, A) and bond angles (deg) with estimated total errors are CH 1.105 ± 0.006, O C 1.213 ± 0.003, 1.404± 0.003, Cph–C(O) 1.478 ± 0.005, C(O)–C(O) 1.558 ± 0.004, Cph–C(O)–C(O) 120.0 ± 0.3, CphC(O)O 120.8 ± 0.4, C(O)–C(O)–C(O) 117.3 ± 0.4, Cph–Cph(CO)–Cph 119.8 ± 0.6. Although there is a general agreement between the gas-phase and crystal molecular structures there are some notable differences. One of the benzene rings is slightly turned about the Cph–C(O) axis in the opposite direction in the gas molecule as compared to the crystal. This causes a marked shortening of the O… H intramolecular contact (to 2.18 A) between the central oxygen and an ortho-hydrogen.

Chemical Reviews, 2000

Figure 7. Lowest-energy structures for some polymeric forms of alkali halides. (a) (NaCl) n clust... more Figure 7. Lowest-energy structures for some polymeric forms of alkali halides. (a) (NaCl) n clusters for cluster sizes n) 2-10; binding energies in eV, decreasing from left to right. (Reprinted with permission from ref 55a. Copyright 1983 Elsevier Science.) (b) (LiF) n and (KCl) n clusters, for cluster sizes n) 3-8. The energy differences with respect to the most stable structures are given, in eV: first row refers to KCl, second row to LiF. (Reprinted with permission from ref 90.

Acta Crystallographica Section B Structural Science, 2008

Journal of Molecular Structure, 2001

Academia Molecular Biology and Genomics, Jun 10, 2024

This personal essay for the new publication Academia Molecular Biology and Genomics highlights so... more This personal essay for the new publication Academia Molecular Biology and Genomics highlights some developments in the early history of molecular biology.