S. M. Jørgensen and the complex connections

Sophus Mads Jørgensen was a brilliant, hardworking and conscientious scientist. As one of the leading chemists of his day, he won international recognition for his meticulous experimental work. S.M. Jørgensen worked within the fields of both organic and inorganic chemistry, but was especially known for his work in complex chemistry. For more than 40 years he was the leading chemist at the College of Advanced Technology, now DTU.

The structure of chemical substances

S.M. Jørgensen worked on the structure of chemical substances, and was a proponent of the Swedish chemist Christian Wilhelm Blomstrand’s chain theory. Jørgensen modified Blomstrand’s model and ensured that it was experimentally well-founded. Many chemists of the time considered the chain model to be the best theory in the field, and the plethora of chemical experiments produced an extensive collection of complex compounds which have been preserved at DTU.

In 1893, the Swiss chemist Alfred Werner proposed a markedly different model for the structure of these substances, and unlike Blomstrand’s and Jørgensen’s chain models, Werner’s model was three-dimensional. The experimental basis for Werner’s new coordination theory was however weak, being based on just a few experimental results, and where experiments were made, they were often undertaken by S.M. Jørgensen. Jørgensen therefore had good reason to criticise Werner’s lack of empirical evidence, which triggered a lengthy debate between Jørgensen, Werner and their respective supporters. However, the outcome was that Werner’s theory became better and better founded, and the chain model eventually fell out of use.

The father of Danish chemistry

S.M. Jørgensen had a long career as a teacher of chemistry at the College of Advanced Technology, now DTU, and alongside his work there, he was also appointed an associate professor and later professor of chemistry at the University of Copenhagen. Jørgensen thus became the teacher of a whole generation of Danish chemists, including the prominent researcher S.P.L. Sørensen of the Carlsberg Research Laboratory, who developed the pH scale.

Thanks to Jørgensen

Respect for S.M. Jørgensen’s life’s work was demonstrated in Alfred Werner’s Nobel Prize acceptance speech of 1913, in which he said, inter alia:

“For the further development of our knowledge of the structure of metal ammine complexes, we are once again indebted to a Nordic scientist, i.e. the Danish chemist S. M. Jørgensen, who expanded and deepened the metal ammine field with studies that have become classics.”