The Frenking Group
With this page we want to introduce the members and the research activities of the computational chemistry group of Prof. Frenking, Philipps Universität of Marburg. For comments or questions you may contact us via eMail: firstname.lastname@example.org. We kindly ask former members of the group to keep us updated about their address, in order that we can contact them for future group meetings.
Research Profile of the Frenking Group
The main research area of the Frenking-Group focuses on quantum chemical calculations of molecules which have unusual bonding situations. We are using state-of-the-art methods for analyzing the nature of the chemical bond. The goal of our work is to build a bridge between the physical mechanism of bond formation and the heuristic bonding models of experimental chemistry. At present we are engaged in a thorough investigation of the nature of the chemical bond across the periodic table using an energy decomposition analysis (EDA). The EDA method makes it possible to quantify the contributions of covalent and classical electrostatic interactions to a chemical bond. It is also possible to estimate the strength of σ, π and δ bonding in multiple bonds. The EDA is very useful in providing a qualitative description of chemical bonds in terms of classical bonding models which is based on accurate quantum chemical calculations rather than speculation.
We are very much interested in new molecules which possess novel types of chemical bonds in compounds of main group elements or transition metals. Our research is often done in cooperation with experimental groups. In collaboration with the group of Prof. R. A. Fischer from the University Bochum we could show that there is a new class of transition metal complexes where the highest coordination number that could experimentally become realized is 12. Complexes like [Mo(ZnCp*)3(ZnMe)9] are substituted homologues of the parent icosahedron [Mo(ZnH)12].
Our research in low-coordinated main group compounds led us to the discovery of an unrecognized class of dicoordinated carbon compounds CL2 where a divalent C(0) atom retains all four valence electrons as two electron lone pairs. The name “carbone” was suggested by us for molecules which possess two donor-acceptor bonds between a strong σ donor ligand L and a bare carbon atom in the 1D state L→C←L. Carbones CL2 have two electron lone-pairs at the divalent C(II) atom while carbones have two lone pairs at divalent C(0). Carbones where L = PR3 (“carbodiphosphoranes”) are known since 1961. Carbones where L = N-heterocyclic carbene have been theoretically predicted by us in 2007 and they were synthesized in 2008. In the meantime we could show that the donor-acceptor bonding situation is also found in stable compounds of the heavier group-14 atoms EL2 where E = Si–Pb which were previously considered as heavy allenes. All compounds EL (C–Pb) are strongly bent. We are presently engaged in theoretical studies of compounds of group-13 and group-15 elements which have a related bonding situation as the ylidones EL2.
Another research area in our group are theoretical investigations of reaction mechanisms. The main focus lies in the field of transition metal mediated reactions. We are particularly interested in homogeneously catalysed reactions. Recent work has been carried out in the field of oxidation reactions of transition metal oxides and peroxides. A particular emphasis of our work lies in the analysis of the calculated data in order to provide an understanding of the theoretical and experimental results in terms of chemical models, which are derived from accurate theoretical calculations rather than ad hoc assumptions.
The following publications are representative examples of our work:
- “Synthesis and Characterization of a Neutral Tricoordinate
Organoboron Isoelectronic with Amines.” R. Kinjo, B. Donnadieu, M. A.
Celik, G. Frenking, G. Bertrand, Science 333, 610 (2011) online (DOI)
- “A Digermyne with a Ge–Ge Single Bond that Activates Dihydrogen in
the Solid State.” J. Li, C. Schenk, C. Goedecke, G. Frenking, C. Jones,
J. Am. Chem. Soc. 133, 18622 (2011) online (DOI)
- “Borylene Complexes (BH)L2 and Nitrogen Cation Complexes
(N+)L2: Isoelectronic Homologues of Carbones
CL2.” M. A. Celik, R. Sure, S. Klein, R. Kinjo, G. Bertrand,
G. Frenking, Chem. Eur. J. 18, 5676 (2012)
- “Spacer Separated Donor-Acceptor Complexes
[D→C6F4→BF3] (D = Xe, CO,
N2) and the Dication
[Xe→C6F4←Xe]2+. A Theoretical Study.”
C. Goedecke, R. Sitt, Gernot Frenking, Inorg. Chem. 51, 11259
(2012) online (DOI)
- “A Stable Singlet Biradicaloid Siladicarbene: (L:)2Si.”
K. C. Mondal, H. W. Roesky, F. Klinke, M. C. Schwarzer, G. Frenking, B.
Niepötter, H. Wolf, R. Herbst-Irmer, D. Stalke, Angew. Chem.
125, 3036 (2013)
online (DOI); Angew. Chem.
Int. Ed. 52, 2963 (2013)
- “Dinitrogen as Double Lewis Acid: Structure and Bonding of
Triphenylphosphinazine N2(PPh3)2.” N.
Holzmann, D. Dange, C. Jones, G. Frenking, Angew. Chem. 125,
online (DOI); Angew. Chem.
Int. Ed. 52, 3004 (2013)
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