Isomerization from Silacyclopentadienyl Complexes to Rhodasilabenzenes, Possible or Not?

Ying huang

Si[Rh']

Si

Possible?

[Rh]

R

R

Contxet

Background

My work

Result Summary and next work

1. What’s metallabenzene complexes?

.

[M] = MLn, MLn-1X or MLn-2X2

2.History

In 1979 ,Thorn and Hoffmann predicted the three classes of stable metallabenzenes

.

D.L. Thorn, R. Hoffmann, Nouv. J. Chim,1979, 3, 39

Mn

L

L

LRh

L

L

Cl

Cl

Rh

L

L

LL

L is a neutral 2e- donor ligand

Metallabenzene

In 1982

Since then Various metallaaromatics have been reported.

the first metallabenzene

W.R. Roper, J. Chem. Soc. Chem.Commun. 1982, 811

M.M. Haley,Organometallics,2003, 22, 3279; M.M. Haley, Chem. Eur. J, 2005, 11,1191

Iridabenzene

3 1

Rhodabenzene

No rhodabenzene has yet been isolated. only rhodabenzvalene was isolated at -30 in 2002.℃

M. M. Haley, Organometallics ,2002,21,4320

48%

Reasons DFT calculations

(diffuse functions for use with the SDD and SDB-cc-pVDZ basis set-RECP combinations are presented for the transition metals.)

M. E.van der Boom,J.M. L. Martin, J. Am. Chem. Soc. 2004, 126, 11699

Rh

H3P PH3

RhH3P

PH3

H3P

20.5 kcalmol-1

-56.8 kcalmol-1

TS

SilabenzeneAromaticity HF(B3LYP/6-311G**)

Si- C :1.771 Å

ASE( aromatic stabilization energy) :70–85% (6-31G*) of that of benzene.

Apeloig, Y., Karni, M. ,Wiley: NewYork,1998, 2, Chapter 1.

But simple neutral silaaromatic compounds are known to be highly reactive.

Si

Free energy surface (kcal/mol) in the reaction of silabenzene with acetylene. ( B3LYP/6-31G(d))

N.Tokitoh,J. Chin. Chem. Soc,2008,55, 3

Reason

synthesis

No silabenzene stable at ambient temperature has ever been reported until 1999.

2,4,6-tris[bis(trimethylsilyl)methyl]phenyl

N . Tokitoh ,Pure Appl. Chem, 1999,71, 495.

Molecular structure of Tbt-substituted silabenzene

bond lengths (Å): Si-C=1.765(1.770)C-C =1.391(1.399;1.381;1.394)

N.Tokiton,Acc. Chem. Res. 2004, 37, 86

X-rayRaman

Schematic drawings of the vibrational modes for the strongest in-plane vibrations of benzene and silabenzene

N.Tokitoh,Organometallics , 2005 , 24 , 6141

Half-Sandwich complexes containing Si

A. Sekiguchi ,J. Am. Chem. Soc,2009, 131, 9902

Rhodium Half-Sandwich

47%

The first group 9 metal complex with the heavy cyclopentadienyl ligand and the first heavy cyclopentadienyl complex of half-sandwich type.

bond lengths (Å): Si1-Si2 =2.2294(8),Si2-Si3 = 2.2807(8), Si1-C2 =1.871(2), Si3-C1 = 1.857(2), C1-C2=1.413(3), Si1-Si4 =2.3864(8), Si2-Si5 =2.3821(8), Si3-Si6 =2.4001(8), Rh1-Si1 =2.5231(6), Rh1-Si2 =2.6845(6), Rh1-Si3 =2.4806(6), Rh1-C1 =2.371(2), Rh1-C2 = 2.323(2), Rh1-C34 =1.900(2), Rh1-C35 =1.873(2), C34-O1 =1.141(3), C35-O2 =1.147(3).

Zhenyang Lin , Guochen Jia,Dalton Trans., 2011, 40, 11315

DFTPackage : Gaussian 03Method: B3LYPbasis sets : 6-31G LanL2DZ (Re(z(f) = 0.869))

[Re']Possible?

[Re]

R

R

energies for the rearrangement reactions of rhenabenzenes. The relative electronic energies and Gibbs free energies at 298 K (in parentheses) are given in kcal mol -1.

Effect of 2OMe substituent on reaction energies for the rearrangement reactions of rhenabenzene.

possible

Energy profiles calculated for the formation of the rearrangement of 1 to 2. The relative electronic energies and Gibbs free energies at 298 K (in parentheses) are given in kcal mol-1.

TS

My work

bond lengths (Å): Si3-Si4 =2.21321 (2.2807),Si2-Si3 =2.21328(2.2294),Si4-C10=1.87771(1.857),Si2-C11=1.87793 (1.871), C10-C11=1.39592(1.413), Si4-Rh=2.51113(2.4806), Si2-Rh=2.51036(2.5231),Si3-Rh= 2.77879 (2.6845), C11-Rh=2.51842(2.323), C10-Rh=2.51852(2.371)

H. Yasuda, V. Ya. Lee, A. Sekiguchi ,J. Am. Chem. Soc, 2009, 131, 9902.

DFTPackage : Gaussian 03Method: m05basis sets : 6-31G * LanL2DZ (Rh (z(f) = 1.350) Si(z(f)= 0.262) P (z(f) =0.340))

The Gibbs free energies and the relative electronic energies (in parentheses) are given in kcal/mol

SiSi

Si

RhH3Si

H3Si

H3Si

CH3

CH3

OC CO

0.0(0.0)

Si

Rh Si

Si

H3Si

SiH3

SiH3

H3CCH3

CO

OC

57.10(58.34)

SiSi

Si

Rh

OC CO

Si

Rh Si

SiCO

OC

52.2(50.1)

Si

Rh

OC CO

Si

Rh

CO

OC34.0(35.8)

0.0(0.0)

Si

Rh

CO

OC

OC31.24(22.03)

0.0(0.0)

-CO

Si

[Rh] + SiH3CH3 + 3CH3CH3 + 2CH2CH2 CH3[Rh] SiH2

+ CH3SiH2CH3 + 4CH3CHCH2

[Rh]=Rh(CO)3

Si

Rh

CO

OC

OC

13.7(10.1)Kcal/mol

B3LYP

Guochen Jia, Zhenyang Lin, Organometallics 2003, 22, 3898

[Os] = Os(PH3)2(CO)I

Conjugation energies:46.66 kcal/mol

Conjugation energies:43.52 kcal/mol

Conjugation energies

Effect of OMe substituent on reaction energies for the rearrangement reactions of rhodasilabenzenes

The blue ones have imaginary frequencies

SiRh

CO 31.63(22.96)

0.0(0.0)

OMe

SiRh

CO35.50(25.90)

0.0(0.0)

OMe Si

RhOC CO

+COOMe

Si

RhOC CO

+COMeO

OC

OC

OC

OC

SiRh

CO

Si

RhOC CO

+CO

Si

RhOC CO

+CO

SiRh

CO

MeO

SiRh

CO

OMe

Si

RhOC CO

+COOMe

SiRhCO

MeO

Si

RhOC CO

+CO

OMe

31.24(22.03)

0.0(0.0)

(16.95)25.89

0.0(0.0)

0.0(0.0)

0.0(0.0)

22.64(13.03)

22.43(12.71) MeO

25.31(25.88)

20.34(21.62)

0.0(0.0)

OC

OC

OC

OC

OC

OC

OC

OC

SiRh

CO

Si

RhOC CO

+CO

MeO

OMeOMe

SiRh

COMeO

Si

RhOC CO

+COMeO

MeO

MeO

SiRh

COMeO

Si

RhOC CO

+COMeO MeO

OMe OMe

0.0(0.0)

0.0(0.0)

0.0(0.0)

19.35(8.75)

15.67(4.44)

12.26(0.714)

MeO

MeOOC

OC

OC

OC

OC

OC

Effect of 2OMe substituent on reaction energies for the rearrangement reactions of rhodasilabenzenes

Effect of PMe3 substituent on reaction energies for the

rearrangement reactions of rhodasilabenzenes.

SiRh

Si

RhOC CO

+CO

SiRh PMe3

Si

RhOC CO

+CO

PMe3

SiRhCO

Si

RhOC CO

+COMe3P

31.24(22.03)

0.0(0.0)

(22.82)31.81

0.0(0.0)

0.0(0.0)

23.62(12.54)

SiRh

Si

RhOC CO

+CO

30.38(21.24)

0.0(0.0)

PMe3

Me3P

SiRh

CO 27.65(18.28)

0.0(0.0)

PMe3 Si

RhOC CO

+COPMe3

Si

RhOC CO

+CO

SiRh

CO

Me3PPMe3

0.0(0.0)

35.33(24.89)

Me3P 1.16(2.86)

-3.56(-2.82)

0.00(0.00)

CO

CO

CO

OC

OC

OC

OC

OC

OC

OC

OC

OC

OC

OC

OC

Effect of PF3 substituent on reaction energies for the rearrangement reactions of rhodasilabenzenes

SiRh

COF3P

Si

RhOC CO

+CO

F3P 0.0(0.0)

9.98(1.42)

Si

RhOC CO

+CO

SiRhCO

F3P

SiRhCO

PF3

Si

RhOC CO

+COPF3

PF3

(27.23)35.12

0.0(0.0)

0.0(0.0)

26.01(16.04)

SiRhCO 27.88

(19.00)

0.0(0.0)

PF3

SiRhCO 25.53

(16.66)

0.0(0.0)

PF3 Si

RhOC CO

+COPF3

Si

RhOC CO

+COF3P

-6.71

(-6.41)

-15.09(-14.88)

0.00(0.00)

OC

OC

OC

OC

OC

OC

OC

OC

OC

OC

Effect of 2PF3 or 3PF3 substituent on reaction energies for the rearrangement reactions of rhodasilabenzenes

SiRhCO

Si

RhOC CO

+CO

PF3 PF3

SiRhCO

Si

RhOC CO

+COF3PF3P

F3P

F3P 0.0(0.0)

0.0(0.0)

14.96(7.72)

4.36(-7.22)

SiRh

CO

Si

RhOC CO

+COF3P

F3P F3P 0.0(0.0)

4.15(-6.42)

PF3 PF3

Si

Si

RhOC CO

+COF3P

F3P

0.0(0.0)

-9.29(-22.66)

SiRhCO

Si

RhOC CO

+COPF3F3P 0.0

(0.0)

7.69(0.47)

PF3

PF3

F3P

F3P

F3P

F3P

F3P

Rh

OCCO

OC

SiRh

CO

Si

RhOC CO

+COF3P

F3P F3P 0.0(0.0)

2.32(-9.68)

F3P PF3PF3

OC

OC

OC

OC

OC

OC

OC

OC

OC

OC

Effect of OMe and PF3 substituent on reaction energies for the rearrangement reactions of rhodasilabenzenes

SiRhCO

Si

RhOC CO

+CO

OMeOMe

SiRhCO

Si

RhOC CO

+COF3PMeO

MeO

F3P 0.0(0.0)

0.0(0.0)

15.60(7.20)

-3.04(-14.87)

Si

Si

RhOC CO

+COF3P

MeO 0.0(0.0)

3.51(-8.04)

Si

RhOC CO

+COOMeF3P 0.0

(0.0)

OMe

F3P

F3P

F3P

Rh

OCCO

OC

Si

F3P

RhOC

COOC

21.87(13.00)

OMe

SiRhCO

Si

RhOC CO

+CO

F3P

F3P 0.0(0.0)

F3P

11.86(1.46)

OMeF3POMe

SiRhCO

Si

RhOC CO

+CO

F3P

F3P 0.0(0.0)

F3P

4.30(-6.57)

F3P

OMe

OMe

OC

OC

OC

OC

OC

OC

OC

OC

path 1

Path 2

TS

Si

Rh

OC

COOC

Si

Rh

OC

COOC

SiRh

OCCO

OC

Si

Rh

OC CO

12.32(15.14)

-2.19(-11.83)

51.10(41.28)

Si

Rh COOC

31.24(22.03)

0.0(0.0)

?

TS2

IN2

IN1

TS1

+CO

SiRh

34.0(35.8)

Si

Rh

OC CO0.0(0.0)

SiRhOC

OC

38.42(41.41)

SiRh

31.24(22.03)

SiRh

OC

OC

CO

OCC O

OCCO

OC

44.38(37.63)

TS2IN1

TS1+CO

1. The thermodynamic of the Silacyclopentadienyl complexes is more stable than Rhodasilabenzene.

2. Computed how the substituents (OMe,PMe3,PF3) on the metallacycle affect the transformation and found that substituents and their locations on the metallacycle have a significant effect on the thermodynamic of the rearrangement reactions.

3. But can not realize the isomerization from Silacyclopentadienyl complexes to Rhodasilabenzenes.

4. Explore the possible pathway for the Rhodasilabenzene to Silacyclopentadienyl complexes.

Result Summary

1. realize the isomerization from Silacyclopentadienyl complexes to Rhodasilabenzenes by using substituents on the metallacycle

2. Find the reaction pathway from Silacyclopentadienyl complexes to Rhodasilabenzenes.

Next work

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Thanks for your attention