Download - Theoretical Study on the silaaromatics
Theoretical Study on the silaaromatics
Speaker: Xuerui WangAdvisor : Jun Zhu
Dec. 23. 2013
Bent's Rule Aromaticity
AromaticityBent' rule
SiO
RX
SiR OX
G = -28.5 ~ 122.2
kcal mol-1
pentalyne metallapentalyne metallasilapentalyne
III
Antiaromatic Aromatic Aromatic
III
[M] Si[M]?
Outline
11
3
[1,3]- substituent Shift for the Formation of the Silabenzenes
2
2
3 Summary and Future work
The aromaticity of metallasilapentalynes
3
Si
Ad
OTMS
TMS
TMSSi
Ad
OTMSTMS
TMS
hv
TMS = SiMe3
Ad = 1-adamantyl
Figure 1.Photochemically Induced [1,3]-Trimethylsilyl Shift from Si to O Applied by Brook et al. to the Formation of the First Silene Stable at room temperature1. Brook, A. G.; Abdesaken, F.; Gutekunst, B.; Gutekunst, G.; Kallury, R. K. J. Chem. Soc., Chem. Commun. 1981, 191. 2. Brook, A. G.; Nyburg, S. C.; Abdesaken, F.; Gutekunst, B.; Gutekunst, G.; Krishna, R.; Kallury, M. R.; Poon, Y. C.; Chang, Y. M.; Wong-Ng, W. J. Am. Chem. Soc. 1982, 104, 5667.
SiSiO
R3SiR3Si
R''R' R' R''
R'''R'''
OSiR3R3Si
R = Me or iPr
R' = H, Me, Et, iPr, tBu, OSiMe3
R'' = H, Me, Et, iPr, tBu
R''' = H, Me, tBu
Rouf, A. M.; Jahn, B. O.; Ottosson, H. Organometallics.2013, 32, 16.
Figure 2. Synthetic route to silabenzenes through the [1,3]-Si O TMS shift by Density functional theory (DFT) calculations
G= -11.1~ -22.6 kcal mol-1
G = 0.6 kcal/molSi SiO OSiMe3Me3Si
Me3SiMe3Si
nonaromatic six membered ring
driving force
Aromaticity
silicon atom is reluctant
to participate in bonding
Kutzelnigg, W. Angew. Chem., Int. Ed. Engl. 1984, 23, 272.
Background
1.928
1.481
1.346
1.472
1.343
1.8671.796
1.391
1.397
1.396
1.393
1.770
1.934
1.482
1.346
1.474
1.344
1.8671.796
1.389
1.3971.397
1.394
1.775
SiSiO
H3SiH OHH3Si
G = -0.3SiSi
OH3Si
Me2N ONMe2H3Si
G = +46.8
a b
A1 A1' A2'A2
4
Bent’s rule : atomic s character tends to concentrate in orbitals that are directed toward electropositive groups and atomic p character tends to concentrate in orbitals that are directed toward electronegative groups.
(a) Bent, H. A. Chem. Rec.1961, 61, 275. (b) Zhu, J.; Lin, Z.; Marder, T. B. Inorg.Chem. 2005, 44, 9384.
silicon atom is reluctant to participate in bonding sp3
Results and Discussion
5
Results and Discussion
Figure 3. [1,3]-substituent shift for the formation of silabenzenes with various substituents .
SiOXH3Si
SiH2Si OX
X = H ISE = -25.3
X = NMe2 ISE = -28.3
NICS(0)zz -11.2 (X = H) -11.6 (X=NMe2)
Evaluate Aromaticity : ISE(isomerization stabilization energy) method and NICS( nucleus independent chemical shift) calculations
SiSiO
R1
X OXR1
X: H, NMe2, F, OMe, Cl, SMe, Me, GeH3, SiH3, AlH2Set A: R1 = SiH3, Set B: R1 = Me
6Figure 4.Plot of reaction free energies (ΔG) against the percentage of the s character of Si in the Si-X bonds.
Results and Discussion
7
Results and Discussion
Figure 5. The plot of s character of Si to the Si-X σ bond vs reaction barriers (ΔG)
8
Results and Discussion
Figure 6. Plot of reaction free energies (ΔG) against the percentage of the s character of Si in the Si-X bonds by replacing the acyl group with methylene group in acylsilane..
9
Silabenzene (X) ΔG ΔG' ΔG'-ΔG
A1' (H)A2' (NMe2)
-0.346.8
27.674.8
27.928.0
A3' (Me)A4' (SMe)A5' (Cl)A6' (OMe)A7' (F)A8' (GeH3)A9' (SiH3)A10' (AlH2)
B1' (H)B2' (NMe2)
B3' (Me)B4' (SMe)B5' (Cl)B6' (OMe)B7' (F)B8' (GeH3)B9' (SiH3)B10' (AlH2)
17.838.177.284.8117.8-0.8-16.1-29.32.354.522.342.481.590.2122.20.1-14.8-28.5
46.167.0105.9114.0147.426.812.5-2.232.983.951.173.3114.1121.8153.830.015.6-0.2
28.328.928.729.229.627.628.631.530.629.428.830.932.631.631.629.930.428.7
Results and Discussion
Figure 7. Plot of reaction free energies (ΔG) against the percentage of the s character of Si in the Si-X bonds in nonaromatic system.
Si
[Os]G
OXR
Si
[Os]
OXR
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Figure 8. Plot of reaction free energies (ΔG) against the percentage of the s character of Si in the Si-X bonds in the osmasilabenznes.
Results and Discussion
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1. The contribution from aromaticity can be evaluated
quantitatively (ca. 30 kcal/mol) in such rearrangement .
2. Bent's rule plays an important role in both the
thermodynamics and kinetics of the rearrangement .
3. Our findings could be a useful guide to the synthesis of
silabenzenes.
Summary
12
Outline
11
3
[1,3]- substituent Shift for the Formation of the Silabenzenes
2
3 Future work
The aromaticity of metallasilapentalynes
13
pentalyne metallapentalyne metallasilapentalyne
III
Antiaromatic Aromatic Aromatic
III
[M] Si[M]?
8e
116 °
10e
129.5 °distorted triple
bondextremely strained
reduce the ring strain significantly
Introduce a metal silicon atom is reluctant to participate in
bonding
Kutzelnigg, W. Angew. Chem., Int. Ed. Engl. 1984, 23, 272.
Zhu, C.; Li, S.; Luo, M.; Zhou, X.; Niu, Y.; Lin, M.; Zhu, J.; Cao, Z.; Lu, X.; Wen, T.; Xie, Z.; Schleyer, P. v. R.; Xia, H. Nat. Chem. 2013, 5, 698.
Background
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Os
Si
PH3
PH3
Cl
A
B2.299
1.8091.381
1.429
1.382
1.4201.363
2.035
2.147
112.6
Ring A;NICS(0) = - 7.3 NICS(1) = - 9.8NICS(2) = - 5.9
NICS(-1) = - 10.0NICS(-2) = - 6.2
NICS(1)zz = - 19.8
Ring B:NICS(0) = - 8.9NICS(1) = - 8.8NICS(2) = - 4.1NICS(-1) = - 9.1NICS(-2) = - 4.2
NICS(1)zz = - 16.2
[Os] E
(E = Si)
(E = Si)
(E = Si)
[Os] E (E = Si)
[Os]=OsCl(PH3)2
(E = C)
(E = C)
(E = C)
(E = C)
[Os] E
[Os] E [Os] E
[Os] E[Os] E
[Os] E
ISE= - 22.8
ISE= - 23.3
ISE= - 21.2
ISE= - 19.6
ISE = -18.7
ISE= - 17.5
ISE= - 16.5
ISE= - 16.9
Results and Discussion
The aromaticity of metallasilapentalynes
Figure 9. The optimized structure 、 the ISEs values of the osmasilapentalynes and the NICS values of the each ring
The effect of ligand
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[Os] Si
N
[Os] Si-18.0 ( -32.8 )+N
N
N
2.388
[Os] SiN
N[Os] Si
0.2 -12.1 )+
The effect of base
[Os]
CH3
CH3
SiH3C
112.7
[Os]
CH3
CH3
SiH3C
partially optimized optimized
74.7
74.0
1
2
3
G = -10.0 E = -8.8
The ring strain
Os
Si
CO
PH3
Cl
Os
Si
CO
CO
Cl
Os
Si
PF3
PF3
Cl
Os
Si
PMe3
PMe3
Cl
Os
Si
CO
PH3
Cl
Os
Si
CO
CO
Cl
Os
Si
PF3
PF3
Cl
Os
Si
PMe3
PMe3
Cl
Os-Si
2.3030.8730
2.3200.8387
2.3080.8895
2.2841.0153
E = -18.09
E = -18.07
E = -18.46
E = -18.89
Os
Si
PH3
PH3
ClOs
Si
PH3
PH3
Cl 2.2910.9784
E = -18.70
HOMO-LOMO
2.96 ev
2.78 ev
2.83 ev
3.10 ev
3.07 ev
[Os]
CH3
CH3
CH3C
129.5
[Os]
CH3
CH3CH3C
partially optimized optimized
74.5
72.8
E = 24.8
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1. From the view of negative ISEs and negative NICS
values compared to benzene both reveal aromaticity in
osmasilapentalyne.
2. osmasilapentalyne prefer -donor ligands than -
accepter ligands.
Summary
17
Outline
1
3
[1,3]- substituent Shift for the Formation of the Silabenzenes
2
3 Future work
The aromaticity of metallasilapentalynes
18
Future work
1. Theoretical study on the [1,3]- substituent shift for the formation of the
stannumbenzenes and germaniumbenzene.
2. Tune the metal center by other transition metals.
[Os] Si Si[M]
M = other metals
GeGeO
R1
X OXR1
SnSnO
R1
X OXR1
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Organophosphorus
compounds
19
pesticide
flame retardant
medicine
antibacterial agents
enzyme inhibitors
anti HIV agents
?P
OEtO
EtOH
P
OEtO
EtO
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Entry initiator eq solvent T(oC) t[h]NMR yield
[%]
1 Mn(OAc)3 2.2 HOAc 80 12 15
2 Mn(OAc)3 2.2 DMF 80 12 5
3 Mn(OAc)3 2.2 THF 80 12 trace
4 AgNO3 0.5 DMF 80 12 trace
5 AIBN 1.2 THF 80 12 trace
Condition Optimization
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致谢
• 感谢朱军老师在学习、生活等各方面给予的关心与指导 !
• 感谢赵玉芬老师、特别要感谢唐果老师、高玉珍师姐、许健师兄、张鹏波、吴巨在实验上的悉心指导和帮助 !
• 感谢实验室的范景兰师姐、黄莹师姐以及其他同学的热心帮助!
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• Thank you for your attention!