|Publication type:||Article in scientific journal|
|Type of review:||Peer review (publication)|
|Title:||Facile synthetic access to rhenium(II) complexes : activation of carbon-bromine bonds by single-electron transfer|
Frech, Christian M.
|Published in:||Chemistry - A European Journal|
|Publisher / Ed. Institution:||Wiley|
|Subject (DDC):||540: Chemistry|
|Abstract:||The five-coordinated Re(I) hydride complexes [Re(Br)(H)(NO)(PR(3))(2)] (R=Cy 1 a, iPr 1 b) were reacted with benzylbromide, thereby affording the 17-electron mononuclear Re(II) hydride complexes [Re(Br)(2)(H)(NO)(PR(3))(2)] (R=Cy 3 a, iPr 3 b), which were characterized by EPR, cyclic voltammetry, and magnetic susceptibility measurements. In the case of dibromomethane or bromoform, the reaction of 1 afforded Re(II) hydrides 3 in addition to Re(I) carbene hydrides [Re(=CHR(1))(Br)(H)(NO)(PR(3))(2)] (R(1)=H 4, Br 5; R=Cy a, iPr b) in which the hydride ligand is positioned cis to the carbene ligand. For comparison, the dihydrogen Re(I) dibromide complexes [Re(Br)(2)(NO)(PR(3))(2)(eta(2)-H(2))] (R=Cy 2 a, iPr 2 b) were reacted with allyl- or benzylbromide, thereby affording the monophosphine Re(II) complex salts [R(3)PCH(2)R'][Re(Br)(4)(NO)(PR(3))] (R'=-CH=CH(2) 6, Ph 7). The reduction of Re(II) complexes has also been examined. Complex 3 a or 3 b can be reduced by zinc to afford 1 a or 1 b in high yield. Under catalytic conditions, this reaction enables homocoupling of benzylbromide (turnover frequency (TOF): 3 a 150, 3 b 134 h(-1)) or allylbromide (TOF: 3 a 575, 3 b 562 h(-1)). The reaction of 6 a and 6 b with zinc in acetonitrile affords in good yields the monophosphine Re(I) complexes [Re(Br)(2)(NO)(MeCN)(2)(PR(3))] (R=Cy 8 a, iPr 8 b), which showed high catalytic activity toward highly selective dehydrogenative silylation of styrenes (maximum TOF of 61 h(-1)). Single-electron transfer (SET) mechanisms were proposed for all these transformations. The molecular structures of 3 a, 6 a, 6 b, 7 a, 7 b, and 8 a were established by single-crystal X-ray diffraction studies.|
|Fulltext version:||Published version|
|License (according to publishing contract):||Licence according to publishing contract|
|Departement:||Life Sciences and Facility Management|
|Appears in collections:||Publikationen Life Sciences und Facility Management|
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Jiang, Y., Blacque, O., Fox, T., Frech, Christian M., & Berke, H. (2010). Facile synthetic access to rhenium(II) complexes : activation of carbon-bromine bonds by single-electron transfer. Chemistry - A European Journal, 16(7), 2240–2249. https://doi.org/10.1002/chem.200902600
Jiang, Y. et al. (2010) ‘Facile synthetic access to rhenium(II) complexes : activation of carbon-bromine bonds by single-electron transfer’, Chemistry - A European Journal, 16(7), pp. 2240–2249. Available at: https://doi.org/10.1002/chem.200902600.
Y. Jiang, O. Blacque, T. Fox, Christian M. Frech, and H. Berke, “Facile synthetic access to rhenium(II) complexes : activation of carbon-bromine bonds by single-electron transfer,” Chemistry - A European Journal, vol. 16, no. 7, pp. 2240–2249, 2010, doi: 10.1002/chem.200902600.
Jiang, Yanfeng, et al. “Facile Synthetic Access to rhenium(II) Complexes : Activation of Carbon-Bromine Bonds by Single-Electron Transfer.” Chemistry - A European Journal, vol. 16, no. 7, 2010, pp. 2240–49, https://doi.org/10.1002/chem.200902600.
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