Isomerization from Silacyclopentadienyl Complexes to Rhodasilabenzenes, Possible or Not? Ying huang

Contxet Background My work Result Summary and next work

1. What’s metallabenzene complexes?. [M] = ML n, ML n-1 X or ML n-2 X 2 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 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 M. M. Haley, Organometallics,2002,21, %

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

Silabenzene Aromaticity 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.

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 ,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-ray Raman 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 = (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, DFT Package : Gaussian 03 Method: B3LYP basis sets : 6-31G LanL2DZ (Re(z(f) = 0.869))

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 = (2.2807),Si2-Si3 = (2.2294),Si4-C10= (1.857),Si2-C11= (1.871), C10-C11= (1.413), Si4-Rh= (2.4806), Si2-Rh= (2.5231),Si3-Rh= (2.6845), C11- Rh= (2.323), C10-Rh= (2.371) H. Yasuda, V. Ya. Lee, A. Sekiguchi,J. Am. Chem. Soc, 2009, 131, DFT Package : Gaussian 03 Method: m05 basis 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

B3LYP Guochen Jia, Zhenyang Lin, Organometallics 2003, 22, 3898 [Os] = Os(PH3)2(CO)I Conjugation energies :46.66 kcal/mol Conjugation energies: kcal/mol Conjugation energies

Effect of OMe substituent on reaction energies for the rearrangement reactions of rhodasilabenzenes The blue ones have imaginary frequencies

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

Effect of PMe 3 substituent on reaction energies for the rearrangement reactions of rhodasilabenzenes.

Effect of PF 3 substituent on reaction energies for the rearrangement reactions of rhodasilabenzenes

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

Effect of OMe and PF 3 substituent on reaction energies for the rearrangement reactions of rhodasilabenzenes

path 1 Path 2 TS

1. The thermodynamic of the Silacyclopentadienyl complexes is more stable than Rhodasilabenzene. 2. Computed how the substituents (OMe,PMe 3,PF 3 ) 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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