Facile synthetic access to rhenium(II) complexes : activation of carbon-bromine bonds by single-electron transfer

Jiang, Yanfeng; Blacque, Olivier; Fox, Thomas; Frech, Christian M.; Berke, Heinz

doi:10.1002/chem.200902600

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
Authors:	Jiang, Yanfeng Blacque, Olivier Fox, Thomas Frech, Christian M. Berke, Heinz
DOI:	10.1002/chem.200902600
Published in:	Chemistry - A European Journal
Volume(Issue):	16
Issue:	7
Page(s):	2240
Pages to:	2249
Issue Date:	2010
Publisher / Ed. Institution:	Wiley
ISSN:	0947-6539 1521-3765
Language:	English
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.
URI:	https://digitalcollection.zhaw.ch/handle/11475/10471
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, Olivier BLACQUE, Thomas FOX, Christian M. FRECH und Heinz BERKE, 2010. Facile synthetic access to rhenium(II) complexes : activation of carbon-bromine bonds by single-electron transfer. Chemistry - A European Journal. 2010. Bd. 16, Nr. 7, S. 2240–2249. DOI 10.1002/chem.200902600

Jiang, Yanfeng, Olivier Blacque, Thomas Fox, Christian M. Frech, and Heinz Berke. 2010. “Facile Synthetic Access to rhenium(II) Complexes : Activation of Carbon-Bromine Bonds by Single-Electron Transfer.” Chemistry - A European Journal 16 (7): 2240–49. https://doi.org/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.