%0 Journal Article %1 doi:10.1002/chem.201703313 %A Koy, Maximilian %A Elser, Iris %A Meisner, Jan %A Frey, Wolfgang %A Wurst, Klaus %A Kästner, Johannes %A Buchmeiser, Michael R. %D 2017 %J Chemistry – A European Journal %K N-heterocyclic alkylidynes alkynes carbenes metathesis molybdenum %N 61 %P 15484-15490 %R 10.1002/chem.201703313 %T High Oxidation State Molybdenum N-Heterocyclic Carbene Alkylidyne Complexes: Synthesis, Mechanistic Studies, and Reactivity %U https://onlinelibrary.wiley.com/doi/abs/10.1002/chem.201703313 %V 23 %X Abstract The first synthetic protocol to high oxidation state molybdenum(VI) N-heterocyclic carbene (NHC) alkylidyne complexes (NHC=1,3-diisopropylimidazol-2-ylidene, 1,3-dimethyl-4,5-R2-imidazol-2-ylidene, R2=H, Cl, CN) is reported. Steric limitations of the NHCs and the benzylidyne are described. All novel complexes were characterized by single crystal X-ray diffraction and solution NMR techniques. It was shown that all complexes presented here show activity in the self-metathesis of 1-phenyl-1-propyne at room temperature. To identify mechanistic differences, an experimental sequence to detect dissociation of ligands was developed. Results reveal dissociation of less electron-donating NHCs in course of the reaction. Mechanistic and reactivity differences were attributed to electronic and steric effects through Tolman's electronic parameter and the percentage of buried volume. Furthermore, Mo-1 containing the 1,3-dimethylimidazol-2-ylidene ligand showed good activity in self-metathesis reactions of p-substituted 1-phenyl-1-propynes with electron-donating moieties at room temperature.

@article{doi:10.1002/chem.201703313, abstract = {Abstract The first synthetic protocol to high oxidation state molybdenum(VI) N-heterocyclic carbene (NHC) alkylidyne complexes (NHC=1,3-diisopropylimidazol-2-ylidene, 1,3-dimethyl-4,5-R2-imidazol-2-ylidene, R2=H, Cl, CN) is reported. Steric limitations of the NHCs and the benzylidyne are described. All novel complexes were characterized by single crystal X-ray diffraction and solution NMR techniques. It was shown that all complexes presented here show activity in the self-metathesis of 1-phenyl-1-propyne at room temperature. To identify mechanistic differences, an experimental sequence to detect dissociation of ligands was developed. Results reveal dissociation of less electron-donating NHCs in course of the reaction. Mechanistic and reactivity differences were attributed to electronic and steric effects through Tolman's electronic parameter and the percentage of buried volume. Furthermore, Mo-1 containing the 1,3-dimethylimidazol-2-ylidene ligand showed good activity in self-metathesis reactions of p-substituted 1-phenyl-1-propynes with electron-donating moieties at room temperature.}, added-at = {2018-11-06T16:52:56.000+0100}, author = {Koy, Maximilian and Elser, Iris and Meisner, Jan and Frey, Wolfgang and Wurst, Klaus and Kästner, Johannes and Buchmeiser, Michael R.}, biburl = {https://puma.ub.uni-stuttgart.de/bibtex/250e26782367b467417239af51fd1ab40/dr.ruethlein}, doi = {10.1002/chem.201703313}, eprint = {https://onlinelibrary.wiley.com/doi/pdf/10.1002/chem.201703313}, interhash = {a0afdf7bf9a944b2c7ac1ce0ba587053}, intrahash = {50e26782367b467417239af51fd1ab40}, journal = {Chemistry – A European Journal}, keywords = {N-heterocyclic alkylidynes alkynes carbenes metathesis molybdenum}, number = 61, pages = {15484-15490}, timestamp = {2018-11-06T15:52:56.000+0100}, title = {High Oxidation State Molybdenum N-Heterocyclic Carbene Alkylidyne Complexes: Synthesis, Mechanistic Studies, and Reactivity}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/chem.201703313}, volume = 23, year = 2017 }