Title: Dinitrosyl rhenium complexes for ring-opening metathesis polymerization (ROMP)
Authors : Frech, Christian Manfred
Blacque, Olivier
Berke, Heinz
Published in : Pure and Applied Chemistry
Volume(Issue) : 78
Issue : 10
Pages : 1877
Pages to: 1887
Conference details: International Symposium on Fine Chemistry and Functional Polymers (FCFP-XV) and the 1st International Symposium on Novel Materials and Synthesis (NMS-I), Novel Materials and their Synthesis, NMS, Novel Materials and their Synthesis, 15th, Shanghai, China, 17-20 October 2005
Publisher / Ed. Institution : De Gruyter
Publisher / Ed. Institution: Berlin
Issue Date: 2006
License (according to publishing contract) : Licence according to publishing contract
Type of review: Peer review (Publication)
Language : English
Subject (DDC) : 540: Chemistry
Abstract: The treatment of benzene solutions of the cations [Re(NO)2(PR3)2][BArF4] (R = Cy and R = iPr; [BArF4] = tetrakis{3,5-bis(trifluoromethyl)phenyl}borate) with phenyldiazomethane afforded the moderately stable cationic rhenium(I) benzylidene dinitrosyl bis(trialkyl) phosphine complexes as [BArF4]- salts in good yields. The cationic rhenium dinitrosyl bisphosphine complexes 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 Z configurations of the double bonds in the polymer chain backbones of over 80 %. The benzylidene derivatives are almost inactive in ROMP catalysis with norbornene and in olefin metathesis. NMR experiments gave first hints for the initial formation of carbene complexes when [Re(NO)2(PR3)2][BArF4] was treated with norbornene. The carbene formation is initiated by an unique reaction sequence where the cleavage of the strained olefinic bond starts with phosphine migration forming a cyclic ylid carbene complex. The [2+2] addition of a norbornene molecule to the Re=C bond leads to the rhenacyclobutane complex, which is expected to be converted into an iminate complex by attack of the ylid function onto one of the NNO atoms followed by Wittig-type phosphine oxide elimination. The formation of phosphine oxide was confirmed by NMR spectroscopy. This species is thought to drive the ROMP metathesis with alternating rhenacyclobutane formations and cycloreversions. The proposed mechanism is supported by density functional theory (DFT) calculations.
Departement: Life Sciences and Facility Management
Publication type: Conference Paper
DOI : 10.1351/pac200678101877
ISSN: 1365-3075
URI: https://digitalcollection.zhaw.ch/handle/11475/10488
Appears in Collections:Publikationen Life Sciences und Facility Management

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