André S. Dreiding (22 June 1919 in

Zürich , neighboring_municipalities = Adliswil, Dübendorf, Fällanden, Kilchberg, Maur, Oberengstringen, Opfikon, Regensdorf, Rümlang, Schlieren, Stallikon, Uitikon, Urdorf, Wallisellen, Zollikon , twintowns = Kunming, San Francisco Zürich ...

– 24 December 2013 in

Herrliberg Herrliberg is a municipality in the district of Meilen in the canton of Zürich in Switzerland. History There are findings dating back to the Bronze Age. In the 8th century, a village called ''Tächliswil'' was established. A hamlet called ...

near Zurich) was a Swiss chemist.University of Zurich, Institute of Organic Chemistry: André S. Dreiding
, accessed 2010-07-22 He finished his high school studies in Zürich and then studied at

Columbia University Columbia University (also known as Columbia, and officially as Columbia University in the City of New York) is a private research university in New York City. Established in 1754 as King's College on the grounds of Trinity Church in Manhatt ...

in New York, where he was awarded BS and MS degrees. After two years as a research assistant at Hoffmann-La Roche, he continued postgraduate studies at the

University of Michigan , mottoeng = "Arts, Knowledge, Truth" , former_names = Catholepistemiad, or University of Michigania (1817–1821) , budget = $10.3 billion (2021) , endowment = $17 billion (2021)As o ...

in Ann Arbor under professor

Werner Emmanuel Bachmann Werner Emmanuel Bachmann (November 13, 1901 – March 22, 1951) was an American chemist. Bachmann was born in Detroit, Michigan where he studied chemistry and chemical engineering at Wayne State University and later at the University of Michiga ...

and was awarded his PhD in 1947. He remained at the university until 1949 as Rackham and Lloyd Postdoctoral Fellow. From 1949 to 1954, Dreiding was an assistant professor at Wayne University, Detroit Institute of Cancer Research. He also temporarily took over Bachmann's teaching and research duties at the University of Michigan after Bachmann's death in 1951 and held them until 1952. In 1954, Dreiding turned to Switzerland and the

University of Zurich The University of Zürich (UZH, german: Universität Zürich) is a public research university located in the city of Zürich, Switzerland. It is the largest university in Switzerland, with its 28,000 enrolled students. It was founded in 1833 f ...

, where he became professor and stayed until his retirement in 1987, after which he was an

emeritus professor ''Emeritus'' (; female: ''emerita'') is an adjective used to designate a retired chair, professor, pastor, bishop, pope, director, president, prime minister, rabbi, emperor, or other person who has been "permitted to retain as an honorary title ...

Dreiding Stereomodels

In 1958, Dreiding invented a

molecular model A molecular model is a physical model of an atomistic system that represents molecules and their processes. They play an important role in understanding chemistry and generating and testing hypotheses. The creation of mathematical models of molecu ...

, used primarily in stereochemistry, named the ''Dreiding Stereomodel''. It was a so-called skeletal model, consisting of slim stainless steel tubes and rods. Unlike the older

ball-and-stick model In chemistry, the ball-and-stick model is a molecular model of a chemical substance which displays both the three-dimensional position of the atoms and the bonds between them. The atoms are typically represented by spheres, connected by rods ...

s, the atoms were not represented by a ball but rather by the point of intersection of the steel tubes.Aldrich Technical Bulletin AL-199: Dreiding Stereomodels
/ref> The intersection area was painted with a color to indicate the atom's identity . As the tubes represented the bonds, the model focused on the geometry of the bonds between atoms rather than the atoms themselves. The Dreiding Stereomodel was not the first skeletal model, but was the first to do away with the connectors used in, e.g.

John Kendrew Sir John Cowdery Kendrew, (24 March 1917 – 23 August 1997) was an English biochemist, crystallographer, and science administrator. Kendrew shared the 1962 Nobel Prize in Chemistry with Max Perutz, for their work at the Cavendish La ...

's earlier

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, res ...

models. Instead, the Dreiding Stereomodels used a valency of the bonds/steel tubes to facilitate connections; they were either a hollow tube or a slightly narrower solid rod which fit into the tube. A tube not connected to another tube represented a

hydrogen Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic ...

atom and the bond from the other atom (for example

carbon Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent—its atom making four electrons available to form covalent chemical bonds. It belongs to group 14 of the periodic table. Carbon mak ...

oxygen Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as ...

nitrogen Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at se ...

) to the hydrogen atoms. This gave the Dreiding Stereomodels a neat look and made the assembly much quicker than earlier skeletal models. They were also quite precise in representing the molecular geometry, so rulers could be used to determine inter-atomic distances and angles.

Availability of Dreiding Stereomodels

The Dreiding Stereomodels were primarily used as a research tool rather than an educational tool for undergraduates. They were widely used by organic chemists, stereochemists and natural products chemists in universities and other research laboratories. The models were sold by Büchi in Europe and by Aldrich in North America. A simpler and cheaper plastic version was later introduced, intended for educational purposes, but never became as widely spread as the original steel version. When molecular modeling software became more readily available in the 1990s, the use of Dreiding Stereomodels declined, production stopped, and the models were discontinued around 2005. However, especially for spectroscopic structure elucidation using NMR and MS, the availability of "hands-on" accurate molecular models remains very valuable. E.g., in natural products chemistry, where structures are often elucidated ab initio, Dreiding Stereomodels can be extremely useful as they allow the rapid assembly of alternative and closely related structures with high geometric precision (e.g., for NOE or 2D NMR interpretations). Because of their widespread use and availability for >40 years, many researchers and departments still maintain and use their collections. In order to ease the general supply problem for spare parts or entire models, the '
Dreiding Model Exchange
'' was established in 2010 at the University of Illinois at Chicago.

References

{{DEFAULTSORT:Dreiding, Andre Swiss chemists Columbia University alumni University of Michigan alumni Wayne State University faculty Academic staff of the University of Zurich 1919 births 2013 deaths