Deactivation Pathways of Neutral Ni(II) Polymerization Catalysts

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First publ. in: Journal of the American Chemical Society 131 (2009), 4, pp. 1565-1574

Konstanzer Online-Publikations-System (KOPS) URN: http://nbn-resolving.de/urn:nbn:de:bsz:352-opus-78991

URL: http://kops.ub.uni-konstanz.de/volltexte/2009/7899/

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plot of In[kMe- Me(I)/I1 vslIT) provided the activation parameters Ml'andM.

Methane Formation from I-DMSO and 3-PMe3 in CD2Cb.

NMR tubes were charged with 5 mg (4.9I'mol) of I-DMSO and 7 mg (6.9 zzmol) of 3-PMe3 (lA equiv of Ni(ll)-H per Ni(II)-CH3) , sealed with rubber septa (fixedwith Nesco Film), and cooled to -30 QC in a cold bath outside the glovebox. CD_2Ch (600 ,uL) was slowly added via syringe, and the tubes were shaken thoroughly to dissolve the solids, giving clear orange solutions. The samples were transferred from the cold bath directly to the prewanned NMR probe, and lH NMR spectra were acquired at predefined time intervals. For data analysis, integral values of the Ni(ll)-H, Ni(1l)-CH_3, andNi(ll)-DMSOresonances (the aver- aged sum of cis and trans isomers in each case) were determined and normalized to Ni(II)-H= 1 att = O. The concentrations of the reactants were calculated from the intial concentration of I-DMSO. Second-order rate constants kg-MeeT)were determined from linear regression of plots of([3-PMe3]t= 0 - [1-DMSO]t

~^0)-¹In([3-PMe3],[l-DMSO],~o/{[3-PMe3]'~⁰[l-DMSO],) versus time (Figure S13 in the Supporting Information). Linear regression of an Eyring plot of the temperature dependence of

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Berkefeld andMecklng kH-M,(T) (i.e., a plot of In[kH-M,(T)II] vs liT) provided the acti vation parameters

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and 8.S*.

Acknowledgment. Financial support by the DFG (Me1388/3- 2) is gratefully acknowledged. We thank Prof. Heiko M. Maller for discussions of NMR spectroscopy and Anke Friemel and Ulrich Haunz for technical support and Lars Bolk for GPC and DSC measurements. S.M. is indebted to the Fonds der Chernischen Industrie and to the Hennann-Schnell Foundation.

Supporting Information Available: Additional NMR specrroscopic data on the characterization and dynamics of 1-DMSO in CD2Ch and methanol-a, solution, the characterization, dynamics, and deactivation pathways of 2-DMSO in DMSO- d6solution, and comprehensive kinetic data obtained from NMR specrroscopic studies on the deactivation processes from I-DM- SO. This material is available free of charge via the Internet at http://pubs.acs .org.