Unprecedented ROMP activity of low-valent rhenium-nitrosyl complexes : mechanistic evaluation of an electrophilic olefin metathesis system

Frech Nabold, Christian M.; Blacque, Olivier; Schmalle, Helmut W.; Berke, Heinz; Adlhart, Christian; Chen, Peter

doi:10.1002/chem.200501025

Publication type:	Article in scientific journal
Type of review:	Peer review (publication)
Title:	Unprecedented ROMP activity of low-valent rhenium-nitrosyl complexes : mechanistic evaluation of an electrophilic olefin metathesis system
Authors:	Frech Nabold, Christian M. Blacque, Olivier Schmalle, Helmut W. Berke, Heinz Adlhart, Christian Chen, Peter
DOI:	10.1002/chem.200501025
Published in:	Chemistry - A European Journal
Volume(Issue):	12
Issue:	12
Page(s):	3325
Pages to:	3338
Issue Date:	12-Apr-2006
Publisher / Ed. Institution:	Wiley
Publisher / Ed. Institution:	Weinheim
ISSN:	0947-6539 1521-3765
Language:	English
Subjects:	Reaction mechanisms; Ring-opening polymerization; Density functional calculations; Metathesis
Subject (DDC):	540: Chemistry 660: Chemical engineering
Abstract:	The reaction of [Re(H)(NO)2(PR3)2] complexes (1 a: R = PCy3; 1 b: R = PiPr3) with [H(OEt2)2][BArF4] ([BArF4] = tetrakis{3,5‐bis(trifluoromethyl)phenyl}borate) in benzene at room temperature gave the corresponding cations [Re(NO)2(PR3)2][BArF4] (2 a and 2 b). The addition of phenyldiazomethane to benzene solutions of 2 a and 2 b afforded the moderately stable cationic rhenium(I)‐benzylidene‐dinitrosyl‐bis(trialkyl)phosphine complexes 3 a and 3 b as [BArF4]− salts in good yields. The complexes 2 a and 2 b catalyze the ring‐opening metathesis polymerization (ROMP) of highly strained nonfunctionalized cyclic olefins to give polymers with relatively high polydispersity indices, high molecular weights and over 80 % Z configuration of the double bonds in the chain backbone. However, these complexes do not show metathesis activity with acyclic olefins. The benzylidene derivatives 3 a and 3 b are almost inactive in ROMP catalysis with norbornene and in olefin metathesis. NMR experiments gave the first hints of the initial formation of carbene complexes from [Re(NO)2(PR3)2][BArF4] (2 a and 2 b) and norbornene. In a detailed mechanistic study ESI‐MS/MS measurements provided further evidence that the carbene formation is initiated by a unique reaction sequence where the cleavage of the strained olefinic bond starts with phosphine migration forming a cyclic ylide–carbene complex, capable of undergoing metathesis with alternating rhenacyclobutane formation and cycloreversion reactions (“ylide” route). However, even at an early stage the ROMP propagation route is expected to merge into an “iminate” route by attack by the ylide function on one of the NNO atoms followed by phosphine oxide elimination. The formation of phosphine oxide was confirmed by NMR spectroscopy. The proposed mechanism is supported further by detailed DFT calculations.
URI:	https://digitalcollection.zhaw.ch/handle/11475/2111
Fulltext version:	Published version
License (according to publishing contract):	Licence according to publishing contract
Departement:	Life Sciences and Facility Management
Organisational Unit:	Institute of Chemistry and Biotechnology (ICBT)
Appears in collections:	Publikationen Life Sciences und Facility Management

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Frech Nabold, C. M., Blacque, O., Schmalle, H. W., Berke, H., Adlhart, C., & Chen, P. (2006). Unprecedented ROMP activity of low-valent rhenium-nitrosyl complexes : mechanistic evaluation of an electrophilic olefin metathesis system. Chemistry - A European Journal, 12(12), 3325–3338. https://doi.org/10.1002/chem.200501025

Frech Nabold, C.M. et al. (2006) ‘Unprecedented ROMP activity of low-valent rhenium-nitrosyl complexes : mechanistic evaluation of an electrophilic olefin metathesis system’, Chemistry - A European Journal, 12(12), pp. 3325–3338. Available at: https://doi.org/10.1002/chem.200501025.

C. M. Frech Nabold, O. Blacque, H. W. Schmalle, H. Berke, C. Adlhart, and P. Chen, “Unprecedented ROMP activity of low-valent rhenium-nitrosyl complexes : mechanistic evaluation of an electrophilic olefin metathesis system,” Chemistry - A European Journal, vol. 12, no. 12, pp. 3325–3338, Apr. 2006, doi: 10.1002/chem.200501025.

FRECH NABOLD, Christian M., Olivier BLACQUE, Helmut W. SCHMALLE, Heinz BERKE, Christian ADLHART und Peter CHEN, 2006. Unprecedented ROMP activity of low-valent rhenium-nitrosyl complexes : mechanistic evaluation of an electrophilic olefin metathesis system. Chemistry - A European Journal. 12 April 2006. Bd. 12, Nr. 12, S. 3325–3338. DOI 10.1002/chem.200501025

Frech Nabold, Christian M., Olivier Blacque, Helmut W. Schmalle, Heinz Berke, Christian Adlhart, and Peter Chen. 2006. “Unprecedented ROMP Activity of Low-Valent Rhenium-Nitrosyl Complexes : Mechanistic Evaluation of an Electrophilic Olefin Metathesis System.” Chemistry - A European Journal 12 (12): 3325–38. https://doi.org/10.1002/chem.200501025.

Frech Nabold, Christian M., et al. “Unprecedented ROMP Activity of Low-Valent Rhenium-Nitrosyl Complexes : Mechanistic Evaluation of an Electrophilic Olefin Metathesis System.” Chemistry - A European Journal, vol. 12, no. 12, Apr. 2006, pp. 3325–38, https://doi.org/10.1002/chem.200501025.