theoretical studies on the polymerization and copolymerization processes catalyzed by the late...
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Theoretical studies on the polymerization
and copolymerization processes catalyzed by
the late transition metal complexes
Theoretical studies on the polymerization
and copolymerization processes catalyzed by
the late transition metal complexes
Artur Michalaka,b and Tom Zieglera
aDepartment of Chemistry,
University of Calgary,
Calgary, Alberta, Canada
bDepartment of Theoretical Chemistry
Jagiellonian University
Cracow, Poland
Artur Michalaka,b and Tom Zieglera
aDepartment of Chemistry,
University of Calgary,
Calgary, Alberta, Canada
bDepartment of Theoretical Chemistry
Jagiellonian University
Cracow, Poland
April 3, 2002April 3, 2002
OutlineOutline
• Influence of catalyst and reaction conditions on the polymer microstructure – DFT calculations and stochastic simulations• Copolymerization of -olefin with methyl acrylate – comparison of Ni- and Pd-based diimine catalysts
• Influence of catalyst and reaction conditions on the polymer microstructure – DFT calculations and stochastic simulations• Copolymerization of -olefin with methyl acrylate – comparison of Ni- and Pd-based diimine catalysts
OutlineOutline
• Influence of catalyst and reaction conditions on the polymer microstructure – DFT calculations and stochastic simulations• Copolymerization of -olefins with methyl acrylate – comparison of Ni- and Pd-based diimine catalysts
• Influence of catalyst and reaction conditions on the polymer microstructure – DFT calculations and stochastic simulations• Copolymerization of -olefins with methyl acrylate – comparison of Ni- and Pd-based diimine catalysts
Ethylene polymerization mechanismEthylene polymerization mechanism
-agostic
-complex
+ ethylene
-agostic
-agosticinsertion
Chain isomerization
-olefin polymerization mechanism-olefin polymerization mechanism
Diimine catalystsDiimine catalysts
n
Propylene:
n
Etylene:
333 methyl branches / 1000 C atoms
Linear chain
Observed: up to 130 branches / 1000 C
Observed: 210 - 333 branches / 1000 C
n
Propylene:
n
Propylene:
n
Etylene:
n
Etylene:
333 methyl branches / 1000 C atoms
Linear chain
Observed: up to 130 branches / 1000 C
Observed: 210 - 333 branches / 1000 C
CCC
CC
CC
C
C
CC
C
CC
C
CC
C
C
CC
C
N CNC CC
C
C
CCC C
CC
Pd
CC
Diimine catalystsDiimine catalysts
Influence of olefin pressure on the polymer structurehigh p - linear structureslow p - hyperbranched structures
Pd – No. of branches independent of pNi – No. of braches influenced by p
n
Propylene:
n
Etylene:
333 methyl branches / 1000 C atoms
Linear chain
Observed: up to 130 branches / 1000 C
Observed: 210 - 333 branches / 1000 C
n
Propylene:
n
Propylene:
n
Etylene:
n
Etylene:
333 methyl branches / 1000 C atoms
Linear chain
Observed: up to 130 branches / 1000 C
Observed: 210 - 333 branches / 1000 C
-olefin polymerization mechanism-olefin polymerization mechanism
Models for the catalyst:Models for the catalyst:
1) generic system: R = H; Ar = H1) generic system: R = H; Ar = H
2) a variety of systems with different substituents:
• R = H; Ar = Ph• R = H; Ar = Ph (Me)2
• R = H; Ar = Ph (i-Pr)2
• R = Me; Ar = H• R = Me; Ar = Ph (Me)2
• R = Me; Ar = Ph (i-Pr)2
• R2 = An; Ar = H• R2 = An; Ar = Ph (i-Pr)2
2) a variety of systems with different substituents:
• R = H; Ar = Ph• R = H; Ar = Ph (Me)2
• R = H; Ar = Ph (i-Pr)2
• R = Me; Ar = H• R = Me; Ar = Ph (Me)2
• R = Me; Ar = Ph (i-Pr)2
• R2 = An; Ar = H• R2 = An; Ar = Ph (i-Pr)2
CC
NN
Pd
R R
Ar Ar
+
CC
NN
Pd
R R
Ar Ar
+
CC
NN
Pd
Models for the catalyst:Models for the catalyst:
1) generic system: R = H; Ar = H1) generic system: R = H; Ar = H
2) a variety of systems with different substituents:
• R = H; Ar = Ph• R = H; Ar = Ph (Me)2
• R = H; Ar = Ph (i-Pr)2
• R = Me; Ar = H• R = Me; Ar = Ph (Me)2
• R = Me; Ar = Ph (i-Pr)2
• R2 = An; Ar = H• R2 = An; Ar = Ph (i-Pr)2
2) a variety of systems with different substituents:
• R = H; Ar = Ph• R = H; Ar = Ph (Me)2
• R = H; Ar = Ph (i-Pr)2
• R = Me; Ar = H• R = Me; Ar = Ph (Me)2
• R = Me; Ar = Ph (i-Pr)2
• R2 = An; Ar = H• R2 = An; Ar = Ph (i-Pr)2
CC
NN
Pd
R R
Ar Ar
+
CC
NN
Pd
R R
Ar Ar
+
CC
CCCC
CNN CCC
CCC C
Pd
Models for the catalyst:Models for the catalyst:
1) generic system: R = H; Ar = H1) generic system: R = H; Ar = H
2) a variety of systems with different substituents:
• R = H; Ar = Ph• R = H; Ar = Ph (Me)2
• R = H; Ar = Ph (i-Pr)2
• R = Me; Ar = H• R = Me; Ar = Ph (Me)2
• R = Me; Ar = Ph (i-Pr)2
• R2 = An; Ar = H• R2 = An; Ar = Ph (i-Pr)2
2) a variety of systems with different substituents:
• R = H; Ar = Ph• R = H; Ar = Ph (Me)2
• R = H; Ar = Ph (i-Pr)2
• R = Me; Ar = H• R = Me; Ar = Ph (Me)2
• R = Me; Ar = Ph (i-Pr)2
• R2 = An; Ar = H• R2 = An; Ar = Ph (i-Pr)2
CC
NN
Pd
R R
Ar Ar
+
CC
NN
Pd
R R
Ar Ar
+
C
CC
C
CCCC
CNN CCC
CCC C
C
Pd
C
Models for the catalyst:Models for the catalyst:
1) generic system: R = H; Ar = H1) generic system: R = H; Ar = H
2) a variety of systems with different substituents:
• R = H; Ar = Ph• R = H; Ar = Ph (Me)2
• R = H; Ar = Ph (i-Pr)2
• R = Me; Ar = H• R = Me; Ar = Ph (Me)2
• R = Me; Ar = Ph (i-Pr)2
• R2 = An; Ar = H• R2 = An; Ar = Ph (i-Pr)2
2) a variety of systems with different substituents:
• R = H; Ar = Ph• R = H; Ar = Ph (Me)2
• R = H; Ar = Ph (i-Pr)2
• R = Me; Ar = H• R = Me; Ar = Ph (Me)2
• R = Me; Ar = Ph (i-Pr)2
• R2 = An; Ar = H• R2 = An; Ar = Ph (i-Pr)2
CC
NN
Pd
R R
Ar Ar
+
CC
NN
Pd
R R
Ar Ar
+
CC
C
CC
C
CC
C
CC
C
C
CNN CCC
CC
C
C C
CC
Pd
CC
Models for the catalyst:Models for the catalyst:
1) generic system: R = H; Ar = H1) generic system: R = H; Ar = H
2) a variety of systems with different substituents:
• R = H; Ar = Ph• R = H; Ar = Ph (Me)2
• R = H; Ar = Ph (i-Pr)2
• R = Me; Ar = H• R = Me; Ar = Ph (Me)2
• R = Me; Ar = Ph (i-Pr)2
• R2 = An; Ar = H• R2 = An; Ar = Ph (i-Pr)2
2) a variety of systems with different substituents:
• R = H; Ar = Ph• R = H; Ar = Ph (Me)2
• R = H; Ar = Ph (i-Pr)2
• R = Me; Ar = H• R = Me; Ar = Ph (Me)2
• R = Me; Ar = Ph (i-Pr)2
• R2 = An; Ar = H• R2 = An; Ar = Ph (i-Pr)2
CC
NN
Pd
R R
Ar Ar
+
CC
NN
Pd
R R
Ar Ar
+
CC
CC
NN
Pd
Models for the catalyst:Models for the catalyst:
1) generic system: R = H; Ar = H1) generic system: R = H; Ar = H
2) a variety of systems with different substituents:
• R = H; Ar = Ph• R = H; Ar = Ph (Me)2
• R = H; Ar = Ph (i-Pr)2
• R = Me; Ar = H• R = Me; Ar = Ph (Me)2
• R = Me; Ar = Ph (i-Pr)2
• R2 = An; Ar = H• R2 = An; Ar = Ph (i-Pr)2
2) a variety of systems with different substituents:
• R = H; Ar = Ph• R = H; Ar = Ph (Me)2
• R = H; Ar = Ph (i-Pr)2
• R = Me; Ar = H• R = Me; Ar = Ph (Me)2
• R = Me; Ar = Ph (i-Pr)2
• R2 = An; Ar = H• R2 = An; Ar = Ph (i-Pr)2
CC
NN
Pd
R R
Ar Ar
+
CC
NN
Pd
R R
Ar Ar
+
CC
C
CC
C
CCCC
CNN CCC
CCC C
C
Pd
C
Models for the catalyst:Models for the catalyst:
1) generic system: R = H; Ar = H1) generic system: R = H; Ar = H
2) a variety of systems with different substituents:
• R = H; Ar = Ph• R = H; Ar = Ph (Me)2
• R = H; Ar = Ph (i-Pr)2
• R = Me; Ar = H• R = Me; Ar = Ph (Me)2
• R = Me; Ar = Ph (i-Pr)2
• R2 = An; Ar = H• R2 = An; Ar = Ph (i-Pr)2
2) a variety of systems with different substituents:
• R = H; Ar = Ph• R = H; Ar = Ph (Me)2
• R = H; Ar = Ph (i-Pr)2
• R = Me; Ar = H• R = Me; Ar = Ph (Me)2
• R = Me; Ar = Ph (i-Pr)2
• R2 = An; Ar = H• R2 = An; Ar = Ph (i-Pr)2
CC
NN
Pd
R R
Ar Ar
+
CC
NN
Pd
R R
Ar Ar
+
C
CC
C
C
CC
C
CC
C
CC
C
C
N CNC CC
CC
C
C C
CC
Pd
CC
Models for the catalyst:Models for the catalyst:
1) generic system: R = H; Ar = H1) generic system: R = H; Ar = H
2) a variety of systems with different substituents:
• R = H; Ar = Ph• R = H; Ar = Ph (Me)2
• R = H; Ar = Ph (i-Pr)2
• R = Me; Ar = H• R = Me; Ar = Ph (Me)2
• R = Me; Ar = Ph (i-Pr)2
• R2 = An; Ar = H• R2 = An; Ar = Ph (i-Pr)2
2) a variety of systems with different substituents:
• R = H; Ar = Ph• R = H; Ar = Ph (Me)2
• R = H; Ar = Ph (i-Pr)2
• R = Me; Ar = H• R = Me; Ar = Ph (Me)2
• R = Me; Ar = Ph (i-Pr)2
• R2 = An; Ar = H• R2 = An; Ar = Ph (i-Pr)2
CC
NN
Pd
R R
Ar Ar
+
CC
NN
Pd
R R
Ar Ar
+
CC
CC
C
CC
C
CC
CC
NN
Pd
Models for the catalyst:Models for the catalyst:
1) generic system: R = H; Ar = H1) generic system: R = H; Ar = H
2) a variety of systems with different substituents:
• R = H; Ar = Ph• R = H; Ar = Ph (Me)2
• R = H; Ar = Ph (i-Pr)2
• R = Me; Ar = H• R = Me; Ar = Ph (Me)2
• R = Me; Ar = Ph (i-Pr)2
• R2 = An; Ar = H• R2 = An; Ar = Ph (i-Pr)2
2) a variety of systems with different substituents:
• R = H; Ar = Ph• R = H; Ar = Ph (Me)2
• R = H; Ar = Ph (i-Pr)2
• R = Me; Ar = H• R = Me; Ar = Ph (Me)2
• R = Me; Ar = Ph (i-Pr)2
• R2 = An; Ar = H• R2 = An; Ar = Ph (i-Pr)2
CC
NN
Pd
R R
Ar Ar
+
CC
NN
Pd
R R
Ar Ar
+
CCC
CC
CC
C
C
CC
C
CC
C
CC
C
C
CC
C
N CNC CC
C
C
CCC C
CC
Pd
CC
DFT calculations:DFT calculations:
A. Michalak, T. Ziegler, "Pd-catalyzed Polymerization of Propene - DFT Model Studies", Organometallics, 18, 1999, 3998-4004.
A. Michalak, T. Ziegler, "DFT studies on substituent effects in Pd-catalyzed olefin polymerization", Organometallics, 19, 2000, 1850-1858.
Examples of results:
Ethylene insertion barrier:DFT: 16.7 kcal/molexp.: 17.4 kcal/mol
Isomerization barrier:DFT: 5.8-6.8 kcal/molexp: 7.2 kcal/mol
C
CC
C
C
CC
C
CC
C
CC
C
C
N CNC CC
CC
C
C C
CC
Pd
CC
Substituent effect in real systemsSubstituent effect in real systems
Electronic preference Steric effect(generic system) (real systems)
alkyl complexes iso-propyl iso-propyl
olefin -complexes iso-propyl alkyl n-propyl alkyl
olefin -complexes propene ethene
propene insertion 2,1- 1,2-
Electronic preference Steric effect(generic system) (real systems)
alkyl complexes iso-propyl iso-propyl
olefin -complexes iso-propyl alkyl n-propyl alkyl
olefin -complexes propene ethene
propene insertion 2,1- 1,2-
Isomerization reactionsIsomerization reactions
0.000.00
+4.56+4.56
-3.42-3.42
0.000.00+5.84+5.84
+1.59+1.59
following1,2-insertion
following2,1-insertion
Isomerization reactionsIsomerization reactions
0.000.00
+4.56+4.56
-3.42-3.42
0.000.00+5.84+5.84
+1.59+1.59
following1,2-insertion
following2,1-insertion
Isomerization reactionsIsomerization reactions
0.000.00
+4.56+4.56
-3.42-3.42
0.000.00+5.84+5.84
+1.59+1.59
following1,2-insertion
following2,1-insertion
1 C atom attached to the catalyst:olefin capture
followed by 1,2- or 2,1-
insertion
Stochastic simulation - how it worksStochastic simulation - how it works
1 C atom attached to the catalyst:olefin capture
followed by 1,2- or 2,1-
insertion
Stochastic simulation - how it worksStochastic simulation - how it works
Primary C attached to the catalyst:1) 1 possible isomerization 2) olefin capture and 1,2- insertion3) olefin capture and 2,1- insertion4) termination
Stochastic simulation - how it worksStochastic simulation - how it works
1
2
3
4
Secondary C attached to the catalyst:1) isomerization to primary C2) isomerisation to secondary C3) olefin capture and 1,2- insertion4) olefin capture and 2,1- insertion5) termination
Stochastic simulation - how it worksStochastic simulation - how it works
Secondary C attached to the catalyst:1) isomerization to secondary C2) isomerisation to secondary C3) olefin capture and 1,2- insertion4) olefin capture and 2,1- insertion5) termination
Stochastic simulation - how it worksStochastic simulation - how it works
Secondary C attached to the catalyst:1) isomerization to primary C2) isomerisation to secondary C3) olefin capture and 1,2- insertion4) olefin capture and 2,1- insertion5) termination
Stochastic simulation - how it worksStochastic simulation - how it works
Primary C attached to the catalyst:1) isomerization to secondary C2) olefin capture and 1,2- insertion3) olefin capture and 2,1- insertion4) termination
Stochastic simulation - how it worksStochastic simulation - how it works
Primary C attached to the catalyst:1) isomerization to tertiary C2) olefin capture and 1,2- insertion3) olefin capture and 2,1- insertion4) termination
Stochastic simulation - how it worksStochastic simulation - how it works
Stochastic simulation - how it worksStochastic simulation - how it works
Stochastic simulation - how it worksStochastic simulation - how it works
Stochastic simulation - how it worksStochastic simulation - how it works
Stochastic simulation - how it worksStochastic simulation - how it works
Probablities of the eventsProbablities of the events
Basic assumption:relative probabilities (microscopic)
= relative rates (macroscopic):
Basic assumption:relative probabilities (microscopic)
= relative rates (macroscopic):
i
π j
=ri
rj
i
i∑ = 1
35
Macroscopic kinetic expressions with microscopic barriers for elementary reactions(calculated or experimental)
Macroscopic kinetic expressions with microscopic barriers for elementary reactions(calculated or experimental)
Use of macroscopic kinetic expressions allows us to discuss the effects of the reaction conditions (temperature and olefin pressure)
Use of macroscopic kinetic expressions allows us to discuss the effects of the reaction conditions (temperature and olefin pressure)
Propylene polymerization (theoretical data)Propylene polymerization (theoretical data)
R = H; Ar = H
CC
NN
Pd
A. Michalak, T. Ziegler, „Stochastic modelling of the propylene polymerization catalyzed by the Pd-based diimine catalyst: influence of the catalyst structure and the reaction conditions on the polymer microstructure”, J. Am. Chem. Soc, 2002, in press.
R=H; Ar= Ph
CC
CCCC
CNN CCC
CCC C
Pd
Propylene polymerization (theoretical data)Propylene polymerization (theoretical data)
R=An; Ar= Ph(i-Pr)2
CCC
CC
CC
C
C
CC
C
CC
C
CC
C
C
CC
C
N CNC CC
C
C
CCC C
CC
Pd
CC
Propylene polymerization (theoretical data)Propylene polymerization (theoretical data)
220
240
260
280
300
320
0 100 200 300 400 500
T [K]
No. of branches / 1000 C
Propylene polymerization - temperature effectPropylene polymerization - temperature effect
T=98K
T=198K
T=298K
T=398K
T=498K
39
C
CC
C
C
CC
C
CC
C
CC
C
C
N CNC CC
CC
C
C C
CC
Pd
CC
220
240
260
280
300
320
0 100 200 300 400 500
T [K]
No. of branches / 1000 C
Propylene polymerization - temperature effectPropylene polymerization - temperature effect
T=98K
T=198K
T=298K
T=398K
T=498K
40
C
CC
C
C
CC
C
CC
C
CC
C
C
N CNC CC
CC
C
C C
CC
Pd
CC
• Two insertion pathways: 1,2- i 2,1-
• Chain straightening follows 2,1-insertion only
•Lower barrier for the 1,2-insertion (by c.a. 0.6 kcal/mol)
• Practically each 2,1-insertion is followed by chain straighening
220
240
260
280
300
320
0.001 0.01 0.1 1
p [ arbitrary units]
No. of branches
Propylene polymerization - pressure effectPropylene polymerization - pressure effect41
C
CC
C
C
CC
C
CC
C
CC
C
C
N CNC CC
CC
C
C C
CC
Pd
CC
220
240
260
280
300
320
0.001 0.01 0.1 1
p [ arbitrary units]
No. of branches
Propylene polymerization - pressure effectPropylene polymerization - pressure effect42
C
CC
C
C
CC
C
CC
C
CC
C
C
N CNC CC
CC
C
C C
CC
Pd
CC
Exp.: 213br. / 1000 C
„Ideal” – no chain straighening333.3
Propylene polymerization - pressure effectPropylene polymerization - pressure effect
p=0.1
p=0.01
p=0.001
p=0.0001
43
C
CC
C
C
CC
C
CC
C
CC
C
C
N CNC CC
CC
C
C C
CC
Pd
CC
Ethylene polymerization by Pd-based diimine catalyst Simulations from experimental data (G)
Ethylene polymerization by Pd-based diimine catalyst Simulations from experimental data (G)
44
CCC
CC
CC
C
C
CC
C
CC
C
CC
C
C
CC
C
N CNC CC
C
C
CCC C
CC
Pd
CC
0
30
60
90
120
150
0.001 0.01 0.1 1
p [ arbitrary units]
No. of branches
Ethylene polymerization by Pd-based diimine catalyst Simulations from experimental data
Ethylene polymerization by Pd-based diimine catalyst Simulations from experimental data
45
CCC
CC
CC
C
C
CC
C
CC
C
CC
C
C
CC
C
N CNC CC
C
C
CCC C
CC
Pd
CC
Exp.
Ethylene polymerization by Pd-based diimine catalyst Simulations from experimental data
Ethylene polymerization by Pd-based diimine catalyst Simulations from experimental data
46
p
Ethylene polymerization - model studies on the effects of catalyst (elementary reaction barriers), temperature, and pressure on the
microstructure of polymers
Ethylene polymerization - model studies on the effects of catalyst (elementary reaction barriers), temperature, and pressure on the
microstructure of polymers
47
Ethylene polymerization - pressure / catalyst effects
Ethylene polymerization - pressure / catalyst effects
0
50
100
150
200
250
300
350
0.0001 0.001 0.01 0.1 1
E2=1E2=2E2=3E2=4E2=5E2=6E2=7E2=8E2=9N
o. o
f b
ran
ches
/ 10
00 C
p [arbitrary units]
E1=1.0 kcal/mol
48
Ethylene polymerization - pressure / catalyst effects
Ethylene polymerization - pressure / catalyst effects
0
50
100
150
200
250
300
350
0.0001 0.001 0.01 0.1 1
E2=1E2=2E2=3E2=4E2=5E2=6E2=7E2=8E2=9N
o. o
f b
ran
ches
/ 10
00 C
p [arbitrary units]
E1=1.0 kcal/mol
49
pressure independent region
0
50
100
150
200
250
300
350
400
450
0.0001 0.001 0.01 0.1 1
E1=2.0 kcal/mol
0
50100
150200
250
300350
400450
500
0.0001 0.001 0.01 0.1 1
E1=3.0 kcal/mol
0
100
200
300
400
500
600
0.0001 0.001 0.01 0.1 1
E1=4.0 kcal/mol
0
100
200
300
400
500
600
0.0001 0.001 0.01 0.1 1
E1=6.0 kcal/mol
50
The faster is the isomerisation (compared to insertions), the more extended is the pressure independent region.
The faster is the isomerisation (compared to insertions), the more extended is the pressure independent region.For Ni-diimine catalyst the isomerisation is slower then for Pdi.e. for Pd the pressure independent region is more extended toward higher values of the pressure
For Ni-diimine catalyst the isomerisation is slower then for Pdi.e. for Pd the pressure independent region is more extended toward higher values of the pressure
The polyethylene galleryThe polyethylene gallery
E1E2=2 kcal/mol
E1E2=5 kcal/mol
E1E2=7 kcal/mol
E1E2=5 kcal/mol
E1E2=5 kcal/mol
p=0.0001; T=298 K
51
Ethylene polymerization with the Ethylene polymerization with the neutral anilinotropone Ni-based neutral anilinotropone Ni-based
catalystcatalyst
Ethylene polymerization with the Ethylene polymerization with the neutral anilinotropone Ni-based neutral anilinotropone Ni-based
catalystcatalyst
Experimental data:
Hiks, F.A., Brookhart M.
Organometallics 2001, 20, 3217.
Experimental data:
Hiks, F.A., Brookhart M.
Organometallics 2001, 20, 3217.
Ethylene polymerization with the Ethylene polymerization with the neutral anilinotropone Ni-based neutral anilinotropone Ni-based
catalystcatalyst
Ethylene polymerization with the Ethylene polymerization with the neutral anilinotropone Ni-based neutral anilinotropone Ni-based
catalystcatalyst
Experimental data:
Hiks, F.A., Brookhart M.
Organometallics 2001, 20, 3217.
Experimental data:
Hiks, F.A., Brookhart M.
Organometallics 2001, 20, 3217.
0
20
40
60
80
100
120
0 100 200 300 400 500 600 700
p [psig]
br./1000C
0
10
20
30
40
50
60
70
80
20 40 60 80 100 120
T [C]
br./1000C
0
5
10
-5
-10
-15
-20N-isomers
O-isomers
Alkyl
AlkylAlkyl
Alkyl
-
-
- -
ins. TS
ins. TS ins. TS
ins. TS
iso. TS
iso. TS
1.9
-12.9
-17.9
0.01.9
9.5
5.8
1.33.4
-17.5-17.1
5.7
1.7
Secondary alkyl Primary alkyl
Ni-anilinotropone catalyst – results for real catalyst
0
20
40
60
80
100
120
140
160
0 0.0038 0.0076 0.0114 0.0152 0.019 0.0228
p [arb.u.]
br./1000C
14 50 100 200 400 600p [psig]
Ni-anilinotropone catalyst – stochastic simulations
Theoret.
Exp.
0102030405060708090
100
40 50 60 70 80 90 100
T [C]
br./1000C
p = 0.011 arb.u. / p = 400 psig
Theoret.
Exp.
Ni-anilinotropone catalyst – stochastic simulations
Polar copolymerization – diimine catalysts
Copolymerization of -olefins with methyl acrylate
N^N-Pd+ - activeN^N-Ni+ - inactive (???)
Diimine catalystsDiimine catalysts
Copolymerization mechanism – acrylate insertionCopolymerization mechanism – acrylate insertion
A. Michalak, T. Ziegler, „DFT Studies on the Copolymerization of -Olefins with Polar Monomers: Ethylene-Methyl Acrylate Copolymerization Catalyzed by a Pd-based Diimine Catalyst” , J. Am. Chem. Soc, 123, 2001, 12266-12278.
0
-10
-5
-15
-20
-25
-30
-35
-40
alkyl agostic+acrylate
acrylate complex
insertion TS
-agostic
-agostic
4-memb. chelate
5-memb. chelate
6-memb. chelate
-20.7
+19.4
-18.5
-5.3
-8.5
-6.1
-1.1
-20.7
CC
C
NN
O
O
C
Pd
C
CC
C
C
C C
N N
Pd
CO
C
C
C
C
C
OC
C C
C
N N
C
Pd
C
CO
C
C
CO
C C
N N
Pd
CO
C
C
C
C
C
C
O
C C
N N
Pd
C
C
O
C
C
C
C
C
O
C C
N N
PdO
C
C
C
CC
O
CC
CC
NN
Pd
C C
C
O
CC
C
C
O
kcal/mol
Acrylate insertion (2,1-) – Pd catalystAcrylate insertion (2,1-) – Pd catalyst
0
-10
-5
-15
-20
-25
-30
-35
-40
alkyl agostic+acrylate
acrylate complex
insertion TS
-agostic
-agostic
4-memb. chelate
5-memb. chelate
6-memb. chelate
CC
C
NN
O
O
C
Pd
C
CC
C
C
C C
N N
Pd
CO
C
C
C
C
C
OC
C C
C
N N
C
Pd
C
CO
C
C
CO
C C
N N
Pd
CO
C
C
C
C
C
C
O
C C
N N
Pd
C
C
O
C
C
C
C
C
O
C C
N N
PdO
C
C
C
CC
O
CC
CC
NN
Pd
C C
C
O
CC
C
C
O
kcal/mol
Acrylate insertion (2,1-) - Pd and Ni catalystsAcrylate insertion (2,1-) - Pd and Ni catalysts
Chelate opening: ethylene insertionChelate opening: ethylene insertion
Two-step chelate openingTwo-step chelate opening
very high insertion barrierslower for Ni-catalyst
Ni – high barrier (higher than insertion)Pd – low barrier (lower than insertion)
low insertion barriers,lower for Ni-catalyst
Two-step chelate openingTwo-step chelate opening
very high insertion barrierslower for Ni-catalyst
Ni – high barrier (higher than insertion)Pd – low barrier (lower than insertion)
A. Michalak, T. Ziegler, „DFT Studies on the Copolymerization of -Olefins with Polar Monomers: Ethylene-Methyl Acrylate Copolymerization Catalyzed by a Pd-based Diimine Catalyst” , J. Am. Chem. Soc, 123, 2001, 12266-12278.
A. Michalak, T. Ziegler, „First-principle MD studies on the methyl acrylate – ethylene copolymerization: comparison of the Ni and Pd-based diimine catalysts”, in preparation
A. Michalak, T. Ziegler, „DFT Studies on the Copolymerization of -Olefins with Polar Monomers: Ethylene-Methyl Acrylate Copolymerization Catalyzed by a Pd-based Diimine Catalyst” , J. Am. Chem. Soc, 123, 2001, 12266-12278.
A. Michalak, T. Ziegler, „First-principle MD studies on the methyl acrylate – ethylene copolymerization: comparison of the Ni and Pd-based diimine catalysts”, in preparation
Copolymerization mechanism– catalyst-monomer complexes
Copolymerization mechanism– catalyst-monomer complexes
A. Michalak, T. Ziegler, „DFT Studies on the Copolymerization of a-Olefins with Polar Monomers: Comonomer Binding by Nickel- and Palladium-Based Catalysts with Brookhart and Grubbs Ligands”, Organometallics, 20, 2001, 1521-1532.
A. Michalak, T. Ziegler, „Molecular Dynamics Studies of the Interconversion Between Oxygen- and Olefin-bound Methyl Acrylate in Nickel- and Palladium-based Diimine Complexes. Implications for the Copolymerization of a-Olefins with Polar Monomers”, in preparation
A. Michalak, T. Ziegler, „DFT Studies on the Copolymerization of a-Olefins with Polar Monomers: Comonomer Binding by Nickel- and Palladium-Based Catalysts with Brookhart and Grubbs Ligands”, Organometallics, 20, 2001, 1521-1532.
A. Michalak, T. Ziegler, „Molecular Dynamics Studies of the Interconversion Between Oxygen- and Olefin-bound Methyl Acrylate in Nickel- and Palladium-based Diimine Complexes. Implications for the Copolymerization of a-Olefins with Polar Monomers”, in preparation
Ni- (inactive):O-complex preferred
Pd- (active) -complex preferred
Preference of the - / O- complex - theoretical catalyst screening test
- / O- complexes- / O- complexes
- / O- complexes- / O- complexes
Methyl acrylate: molecular electrostatic potential
Electrostatic origin of the O-complex preferrence for Ni-system
Table 1. The monomer binding energies for the generic models for the Ni- and Pd-based Brookhart and Grubbs catalysts.
Catalyst Monomer E (C=C)1 E (O)2 E(C=C) - E(O)2
1a. Brookhart/Ni MA -17.10 -21.10 +4.001b. Brokhart/Pd MA -20.70 -17.30 -3.40
1a. Brookhart/Ni VA -17.07 -17.75 +0.681b. Brokhart/Pd VA -20.12 -14.96 -5.16
1a. Brookhart/Ni FMA -13.93 -16.25 +2.321b. Brokhart/Pd FMA -17.95 -12.92 -5.03
1a. Brookhart/Ni FVA -11.41 -9.99 -1.421b. Brokhart/Pd FVA -14.76 -8.10 -6.66
3a. Grubbs/Ni MA -17.74 -10.18 -7.563b. Grubbs/Pd MA -24.34 -10.17 -14.17
3a. Grubbs/Ni VA -16.09 -9.72 -7.183b. Grubbs/Pd VA -21.72 -9.56 -12.16
1 -complex stabilization energy, in kcal/mol;2 stabilization energy of the O-complex, in kcal/mol;3 the difference in the energies of the -complex and O-complex;
Table 1. The monomer binding energies for the generic models for the Ni- and Pd-based Brookhart and Grubbs catalysts.
Catalyst Monomer E (C=C)1 E (O)2 E(C=C) - E(O)2
1a. Brookhart/Ni MA -17.10 -21.10 +4.001b. Brokhart/Pd MA -20.70 -17.30 -3.40
1a. Brookhart/Ni VA -17.07 -17.75 +0.681b. Brokhart/Pd VA -20.12 -14.96 -5.16
1a. Brookhart/Ni FMA -13.93 -16.25 +2.321b. Brokhart/Pd FMA -17.95 -12.92 -5.03
1a. Brookhart/Ni FVA -11.41 -9.99 -1.421b. Brokhart/Pd FVA -14.76 -8.10 -6.66
3a. Grubbs/Ni MA -17.74 -10.18 -7.563b. Grubbs/Pd MA -24.34 -10.17 -14.17
3a. Grubbs/Ni VA -16.09 -9.72 -7.183b. Grubbs/Pd VA -21.72 -9.56 -12.16
1 -complex stabilization energy, in kcal/mol;2 stabilization energy of the O-complex, in kcal/mol;3 the difference in the energies of the -complex and O-complex;
1a (Ni)1a (Ni)
1b (Pd)1b (Pd)
Fig 1. MA - and O-complexes with diimine catalysts
Copolymerization of ethylene with methyl acrylateCopolymerization of ethylene with methyl acrylate
• Ni-catalyst poissoned at lower temperatures by formation of the O-complexes and chelates
• Chelate opening has to happen prior to ethylene insertion (at the -complex stage);
• Electrostatic origin of the O-complex stability for the Ni-catalyst suggests use of neutral complexes
• Ni-catalyst poissoned at lower temperatures by formation of the O-complexes and chelates
• Chelate opening has to happen prior to ethylene insertion (at the -complex stage);
• Electrostatic origin of the O-complex stability for the Ni-catalyst suggests use of neutral complexes
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