Kinetic and Thermodynamic Control of Nitrile Dissociation in the Complexes (RFe,RC)/(SFe,RC)-[CpFe(Prophos)NCR]X (X = I, PF6) by the Inductive Effect
| Autor: | Takaki Kurosawa, Takashi Tsuno, Henri Brunner, Hikaru Kitamura, Hayato Ike |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
Nitrile
010405 organic chemistry Chemistry Organic Chemistry Kinetics Diastereomer 010402 general chemistry Kinetic energy 01 natural sciences Kinetic control Dissociation (chemistry) 0104 chemical sciences Inorganic Chemistry chemistry.chemical_compound Crystallography Epimer Physical and Theoretical Chemistry Inductive effect |
| Zdroj: | Organometallics. 37:1892-1899 |
| ISSN: | 1520-6041 0276-7333 |
| DOI: | 10.1021/acs.organomet.8b00146 |
| Popis: | The chiral-at-metal complexes (RFe,RC)/(SFe,RC)-[CpFe(Prophos)NCR]X (X = I, PF6; R = Et, Ph, p-substituted Ph) were prepared, and the diastereomers were separated by fractional crystallization. Eight diastereomerically pure complexes (SFe,RC)-[CpFe(Prophos)NCR]X could be characterized by X-ray crystallography. The kinetics of epimerization with respect to the labile Fe-configuration in CDCl3 at ambient temperatures was measured for the EtCN, PhCN, and (p-C6H4NMe2) complexes. The half-lives of 162 and 760 min of the first-order reactions of (SFe,RC)-[CpFe(Prophos)NCPh]PF6 and (SFe,RC)-[CpFe(Prophos)NC(p-C6H4NMe2)]PF6 at 293 K demonstrate the importance of the inductive effect in the rate-determining cleavage of the Fe–NCR bond. The diastereomer ratios of 5:95 to 10:90 at equilibrium under thermodynamic control were strongly in favor of the (SFe,RC)-[CpFe(Prophos)NCR]X diastereomers. In ligand exchange reaction reactions, (RFe,RC)/(SFe,RC) diastereomer ratios of up to 35:65 were observed under kinetic control. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|