Microheterogeneous catalytic system Nicolloid0-NiI-NiII for low-pressure polymerization of butadiene. I. Redox equilibria as studied by electron paramagnetic resonance in system Ni(acac)2-BF3·O(C2H5)2-AlR3

1972 ◽  
Vol 37 (2) ◽  
pp. 573-584 ◽  
Author(s):  
A. Tkáč ◽  
A. Staško
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Catalytic System ◽  
Low Pressure ◽  
Paramagnetic Resonance ◽  
Electron Paramagnetic ◽  
Redox Equilibria

scholarly journals First experimental evidence for a bis-ethene chromium(I) complex forming from an activated ethene oligomerization catalyst

2020 ◽  
Vol 6 (51) ◽  
pp. eabd7057
Author(s):  
S. Chabbra ◽  
D. M. Smith ◽  
N. L. Bell ◽  
A. J. B. Watson ◽  
M. Bühl ◽  
...  
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Experimental Evidence ◽  
Catalytic System ◽  
Isotope Labeling ◽  
Catalytic Transformation ◽  
Mechanistic Studies ◽  
Paramagnetic Resonance ◽  
Electron Paramagnetic

A bis-ethene chromium(I) species, which is the postulated key intermediate in the widely accepted metallacyclic mechanism for ethene oligomerization, is experimentally observed. This catalytic transformation is an important commercial route to linear α-olefins (primarily, 1-hexene and 1-octene), which act as comonomers for the production of polyethene. Here, electron paramagnetic resonance studies of a catalytic system based on [Cr(CO)4(PNP)][Al(OC(CF3)3)4] [PNP = Ph2PN(iPr)PPh2] activated with Et6Al2 provide the first unequivocal evidence for a chromium(I) bis-ethene complex. The concentration of this species is enhanced under ethene and isotope labeling studies that confirm its composition as containing [Cr(C2H4)2(CO)2(PNP)]+. These observations open a new route to mechanistic studies of selective ethene oligomerization.

ELECTRON PARAMAGNETIC RESONANCE STUDIES OF PHASE TRANSITIONS IN KCN

1976 ◽  
Vol 37 (C7) ◽  
pp. C7-241-C7-246 ◽  
Author(s):  
J.P. VON DER WEID ◽  
L.C. SCAVARDA DO CARMO ◽  
R. R. DO SANTOS ◽  
B. KOILLER ◽  
S. COSTA RIBEIRO ◽  
...  
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Phase Transitions ◽  
Paramagnetic Resonance ◽  
Electron Paramagnetic

Electron paramagnetic resonance in silicon and germanium

1964 ◽  
Vol 83 (7) ◽  
pp. 433-502 ◽  
Author(s):  
L.D. Bogomolova ◽  
V.N. Lazukin ◽  
I.V. Chepeleva
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Paramagnetic Resonance ◽  
Silicon And Germanium ◽  
Electron Paramagnetic
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