Egbertus Havinga

Egbertus Havinga (born July 5, 1909 in Amersfoort , † November 22, 1988 in Wassenaar ) was a Dutch chemist and professor of organic chemistry at the University of Leiden (organic chemistry, stereochemistry).

Live and act

Havinga studied chemistry and physics in Utrecht and received his doctoral degree in 1934 with a combination of organic chemistry and theoretical physics. His teachers in Utrecht were Hendrik Anthony Kramers and Fritz Kögl . In 1939 he was with Fritz Kögl with the work Monomoleculaire; structuur en chemical reacties (Monomolecular layers; Structure and Reactions) PhD . Then he was a conservator at the Medicinal Chemistry Laboratory in the Faculty of Veterinary Medicine in Utrecht. In 1946 he was the successor to Jan Johannes Blanksma on the chair for organic chemistry at the University of Leiden. In 1979 he retired.

He dealt with theoretical investigations in organic chemistry (which was unusual at the beginning of his career in the Netherlands) and introduced modern physical investigation methods in his laboratory in Leiden (X-ray and electron diffraction, various spectroscopic methods, measurement of dipole moments). He had many students in the Netherlands. Havinga was particularly interested in the relationship between the spatial structure (conformation) of organic molecules and their reactivity. He initiated stereochemical model studies on flexible aliphatic ring systems and clearly demonstrated that the chair form of cyclohexane and some of its simple derivatives is energetically the most favorable, while for some other derivatives (such as diketones ) a more flexible form is more favorable. These fundamental insights into the dynamic equilibrium of molecules with different spatial structures later led to the discovery and explanation of the anomeric effect . He later investigated photoreactions of vitamin D (transition between isomers), investigations into the connection between orbital symmetry and reactions with his colleague LJ Oosterhoff (in advance of the later Woodward-Hoffmann rules ) and conformational equilibria (NEER principle: Non Equilibrium of Excited Rotamers). He also dealt with photo-substitution reactions on aromatics ( heterolysis , they were previously associated with homolysis and radical binding ), which were discovered by chance in his laboratory in nitro compounds of aromatics that were exposed to sunlight over the lunch break.

In 1973 he gave the Paul Karrer lecture on vitamin D.

He had been a member of the Royal Netherlands Academy of Sciences since 1956 and he was a Knight of the Order of the Dutch Lion. The University of Leiden awards a medal named after him.

He was married to Louise D. Oversluys, a doctor of pharmacy.

literature

• Th.J. de Boer: Levensbericht E. Havinga, in: Jaarboek KNAW, 1989, Amsterdam, pp. 152–156

Web links

• Biographical Portaal van Nederland

Individual evidence

1. ↑ biographical data, publications and Academic pedigree of Egbert Havinga at academictree.org, accessed on February 8 2018th