Periodic Reporting for period 1 - cAAC-Light (New Strategies for Bond Activation and Catalysis with subvalent Main Group Complexes)
Berichtszeitraum: 2021-09-01 bis 2022-08-31
The main objectives of this projects are:
To synthesize a variety of MG-carbene complexes to explore their capacity towards the activation of small molecules.
To test the capacity of the MG-carbene and MG-TM complexes for the light-driven activation of non-classical bonds.
To explore the cooperativity of the MG/TM complexes on the reversible activation of E-H bonds.
To synthesize and characterize a variety of hybrid MG/TM complexes based on P,carbene chelating scaffolds functionalised with bulky moieties or N,P ligands.
Once the synthesis of the ligands was performed, the following step was the preparation of the MG complexes. GeCl2 was the precursor chosen for this aim. The reactivity of the GeCl2 with cAAC in the presence of catalytic amounts of lithium diisopropylamide (LDA) leads to the Ge(cAAC)Cl2. Using the same procedure for the MICs carbenes the formation of Ge(MIC)Cl2 was performed. Also, we prepared Ge(terpenyl)Cl and Ge(terphenyl)2 compounds following the synthesis previously reported by Power´s group (Figure 1).
The next step was the abstraction of one or two chlorides ligands of the Ge(MIC)Cl2 and Ge(cAAC)Cl2 for the preparation of Ge(II)(Carbene)Cl+ or Ge(0)(carbene) complexes. These species should be more reactive for the activation of small molecules. We are still working on the characterization and isolation of these species due to their great instability.
In the area of Ge(terphenyl)Cl and Ge(terphenyl)2 complexes, Ge-TM complexes were isolated and characterized. Also the activation of small molecules and the catalytic hydrogenation, hydrosilylation and isomerization of olefins were performed (Figure 2), revealing an unusual selectivity pattern that we attribute to the combination of a germanium centre with rhodium, one of the core ideas of this Marie Curie proposal. These results have already led to a publication in ChemCatChem (2022, 14, e2022001).