Mechanisms in homogeneous catalysis

Dr. Hans-Joachim Drexler

For many years, the group's work has focused on investigations into the activation and deactivation of catalysts and their influence on the mechanism of homogeneously catalysed reactions. The insights gained lead to the reactions studied being more efficient and thus more sustainable. In addition to basic research, especially in the field of selective hydrogenation, many reactions have been and are being investigated for their optimisation potential in cooperation with partners from research and industry. The investigations are mostly carried out as a combination of kinetic measurements (in situ operando NMR and UV/Vis spectroscopy as well as our own developed method of online registration of gas consumption under isobaric conditions1) and coordination chemical investigations (NMR, UV-Vis, X-ray analysis).

One focus of our work in the field of basic research is on studies of the organometallic chemistry of rhodium-bis(phosphine) complexes in homogeneous catalysis. Examples are the activation of ammonia with complexes of the type [Rh(PP)(µ2-OMe)]2 (PP e.g. DIOP), the hydrogenation of prochiral olefins, e.g. with the ammine complex [Rh(binap)(NH3)2]2, cyclisation reactions3, as well as investigations on catalyst deactivation in propargylic C-H activation. The latter work is being carried out as part of a DFG project in cooperation with the Breit group (Freiburg).4


In cooperation with industry (e.g. Hansen & Rosenthal, DSM), systems for replacing toxic solvents, e.g. in extraction, are being investigated in addition to hydrogenation. Here, the transfer of a process to pilot scale was recently achieved.

The group uses standard equipment for working under inert conditions (high-vacuum Schlenk lines, gloveboxes), electrochemical equipment, fully automated volumetric instruments for measuring gas evolution and gas consumption, which can also be operated under photochemical conditions, autoclave equipment, as well as gas chromatography, 31P benchtop NMR spectroscopy, mass spectrometry and UV-vis spectroscopy.

Students interested in organometallic synthesis, ligand design and the application in homogeneous catalysis are welcome to join the group as part of internships, bachelor and master theses or PhD projects.

Please send an email to hans-joachim.drexler{at} or torsten.beweries{at}


[1] D. Heller, A. H. M. de Vries, J. G. de Vries, in „Handbook of Homogeneous Hydrogenation“ ed. by . H. G. deVries and C. Elsevier, chapter 10, 257-293, 2007.
[2] M. Horstmann, H. J. Drexler, N. Jannsen, W. Baumann, D. Heller, J. Organomet. Chem. 2020, 922, 121342.
[3] I. Thiel, M. Horstmann, P. Jungk, S. Keller, F. Fischer, H.-J. Drexler, D. Heller, M. Hapke, Chem. Eur. J. 2017, 23, 17048-17057.
[4] S. Möller, N. Jannsen, J. Rüger, H.-J. Drexler, M. Horstmann, F. Bauer, B. Breit, D. Heller, Chem. Eur. J. 2021, 27, 14034-14041.