Stubenhofer, Markus and Kuntz, Christian and Bodensteiner, Michael and Zenneck, Ulrich and Sierka, Marek and Scheer, Manfred (2010) The Complexed 1,3-Diphospha-2-Arsaallyl Radical and Its Cationic and Anionic Derivatives. CHEMISTRY-A EUROPEAN JOURNAL, 16 (25). pp. 7488-7495. ISSN 0947-6539,
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Photolysis of [Cp*As{W(CO)(5)}(2)] (1a) in the presence of Mes*P=PMes* (Mes*=2,4,6-tri-tert-butylphenyl) leads to the novel 1,3-diphospha-2-arsaallyl radical [(CO)(5)W(mu,eta(2):eta(1)P(2)AsMes*(2))W(CO)(4)] (2a). The frontier orbitals of the radical 2a are indicative of a stable pi-allylic system that is only marginally influenced by the d orbitals of the two tungsten atoms. The SOMO and the corresponding spin density distribution of the radical 2a show that the unpaired electron is preferentially located at the two equivalent terminal phosphorus atoms, which has been confirmed by EPR spectroscopy. The protonated derivative of 2a, the complex [(CO)(5)W-(mu,eta(2):eta(1)-P(2)As(H)Mes*(2))W(CO)(4)] (6a) is formed during chromatographic workup, whereas the additional products [Mes*P=PMes*(W(CO)(5)}]1 as the Z-isomer (3) and the E-isomer (4), and [As(2){W(CO)(5)}(3)] (5) are produced as a result of a decomposition reaction of radical 2a. Reduction of radical 2a yields the stable anion [(CO)(5)W(mu,eta(2):eta(1)-P(2)AsMes*(2))W(CO)(4)]- in 7a, whereas upon oxidation the corresponding cationic complex [(CO)5W(mu,eta(2):eta(1)-P(2)AsMes*(2))W(CO)(4)](-) [SbF(6)] (8a) is formed, which is only stable at low temperatures in solution. Compounds 2a, 7a, and 8a represent the hitherto elusive complexed redox congeners of the diphospha-arsa-allyl system. The analogous oxidation of the triphosphaallyl radical [(CO)(5)W(mu,eta(2):eta(1)-P(3)Mes*(2)(CO)(4)] (2b) also leads to an allyl cation, which decomposes under CH activation to the phosphine derivative [(CO)(5)W{mu,eta(2):eta(1)-P(3)Mes*) (C(5)H(2)tBu(2)C(CH(3))(2)CH(2))}W(CO)(4)] (9), in which a CH bond of a methyl group of the Mes* substituent has been activated. All new products have been characterized by NMR spectrometry and IR spectroscopy, and compounds 2a, 3, 6a, 7a, and 9 by X-ray diffraction analysis.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | PHOSPHORUS TRIPLE BOND; MAIN-GROUP; COORDINATION CHEMISTRY; BASIS-SETS; AB-INITIO; LIGANDS; ENERGY; REACTIVITY; ELEMENTS; GROUP-15; allyl ligands; arsenic; arsenidenes; phosphorus; radicals |
| Subjects: | 500 Science > 540 Chemistry & allied sciences |
| Divisions: | Chemistry and Pharmacy > Institut für Anorganische Chemie > Chair Prof. Dr. Manfred Scheer |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 12 Aug 2020 13:02 |
| Last Modified: | 12 Aug 2020 13:02 |
| URI: | https://pred.uni-regensburg.de/id/eprint/25397 |
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