Unsupported Mg–Alkene Bonding
| Autor: | Katharina Thum, Alexander Friedrich, Sjoerd Harder, Jürgen Pahl, Jens Langer, Holger Elsen |
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| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Magnesium Alkene Complexes | Hot Paper
magnesium 010402 general chemistry 01 natural sciences Catalysis Dissociation (chemistry) noncovalent interactions chemistry.chemical_compound Transition metal Cyclooctene Non-covalent interactions Lewis acids and bases alkene ligands chemistry.chemical_classification Full Paper 010405 organic chemistry Alkene Organic Chemistry Intermolecular force General Chemistry Full Papers 0104 chemical sciences Crystallography chemistry Bromobenzene density functional calculations Lewis acids ddc:546 |
| Zdroj: | Chemistry (Weinheim an Der Bergstrasse, Germany) |
| Popis: | The first intermolecular early main group metal–alkene complexes were isolated. This was enabled by using highly Lewis acidic Mg centers in the Lewis base‐free cations (MeBDI)Mg+ and (tBuBDI)Mg+ with B(C6F5)4 − counterions (MeBDI=CH[C(CH3)N(DIPP)]2, tBuBDI=CH[C(tBu)N(DIPP)]2, DIPP=2,6‐diisopropylphenyl). Coordination complexes with various mono‐ and bis‐alkene ligands, typically used in transition metal chemistry, were structurally characterized for 1,3‐divinyltetramethyldisiloxane, 1,5‐cyclooctadiene, cyclooctene, 1,3,5‐cycloheptatriene, 2,3‐dimethylbuta‐1,3‐diene, and 2‐ethyl‐1‐butene. In all cases, asymmetric Mg–alkene bonding with a short and a long Mg−C bond is observed. This asymmetry is most extreme for Mg–(H2C=CEt2) bonding. In bromobenzene solution, the Mg–alkene complexes are either dissociated or in a dissociation equilibrium. A DFT study and AIM analysis showed that the C=C bonds hardly change on coordination and there is very little alkene→Mg electron transfer. The Mg–alkene bonds are mainly electrostatic and should be described as Mg2+ ion‐induced dipole interactions. Weak but important: The first unsupported alkene complexes of an s‐block metal have been realized. Alkene–magnesium coordination is in all cases asymmetric and leads to polarization of π‐electron density in the C=C bond. There is no alkene→Mg charge transfer and only minimal C=C bond lengthening. Although weak, these interactions are important in early main group metal catalysis. |
| Databáze: | OpenAIRE |
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