Brunner, Henri and Kitamura, Hikaru and Tsuno, Takashi (2017) Kinetics of the S(N)1 Dissociation of Ligands L (Nitrites, Phosphines) in the Complexes [CpFe(P-P)L]PF6 with Variable Chelate Ring Size. A Surprising Bimolecular Substitution in the Nonchelate Complex [CpFe(PPh2Me)(2)L]PF6. ORGANOMETALLICS, 36 (13). pp. 2424-2436. ISSN 0276-7333, 1520-6041
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The complexes [CpFe{Ph2P(CH2)(n)PPh2}NCMe]-PF6, [CpFe(PPh2Me)(2)NCMe]PF6, and [CpFe{Ph2P(CH2)(n)PPh2}-PPh2(OR)PF6, R = Me, Et, and iPr, with chelate ring sizes between 4 and 7 were synthesized and characterized by spectroscopy and Xray analysis. In these complexes, the monodentate ligands acetonitrile and PPh2(OR) tend to dissociate. The kinetics of the ligand exchanges MeCN/P(OMe)(3) and PPh2(OR)/P(OMe)(3) was measured. In the acetonitrile series, the first-order reaction of the five-membered chelate complex [CpFe(dppe)NCMe]PF6 had a half-life of 549 min in CDCl3 at 293 K. The other chelate complexes [CpFe(P-P)NCMe]PF6 and the nonchelate analogue [CpFe(PPh2Me)(2)NCMe]PF6 reacted faster by factors of 20-50. The PPh2(OR) series revealed a dramatic difference between the complexes [CpFe(P-P)PPh2(OR)]PF6 with five- and six-membered chelate rings. The PPh2(OR)/P(OMe)(3) exchange in the dppp complex (six-membered chelate ring) was 500 times faster than in the dppe complex (five-membered chelate ring). This is due to the increase of the P-Fe-P angle in the dppp chelate ring, which diminishes the binding pocket of the PPh2(OR) ligand. In the nonchelate complex [CpFe(PPh2Me)(2)NCMe]PF6, a novel and unexpected bimolecular PPh2Me/PPh2(OMe) substitution was observed.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | CHIRAL-AT-METAL; CRYSTAL-STRUCTURES; IRON COMPLEXES; ARENE CATIONS; ACETONITRILE; REACTIVITY; CHEMISTRY; EXCHANGE; ATOMS; |
| Subjects: | 500 Science > 540 Chemistry & allied sciences |
| Divisions: | Chemistry and Pharmacy > Institut für Anorganische Chemie Chemistry and Pharmacy > Institut für Anorganische Chemie > Alumni or Retired Professors > Prof. Dr. Henri Brunner |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 14 Dec 2018 13:16 |
| Last Modified: | 20 Feb 2019 07:54 |
| URI: | https://pred.uni-regensburg.de/id/eprint/1547 |
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