Bulletin of the Korean Chemical Society

Korean Chemical Society (대한화학회)
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Cis-Trans Isomerization of Dimeric $[Me_2Al(μ-NH^tBu)]_2$

  • Published : 1996.12.20
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Abstract

The trans (2a)-cis (2b) isomerization of [Me2Al(μ-NHtBu)]2 (2) has been studied by 1H NMR spectroscopy. The equilibrium has been observed to follow reversible first order kinetics with ΔH0=2.22±0.07 kJmol-1 and ΔS0=2.85±0.07 JK-1mol-1. The activation parameters for the conversion 2a→2b are ΔH1=49.7±2.3 kJmol-1 and ΔS1=-126.3±0.2 JK-1mo1-1 and for the reverse reaction 2b→2a are ΔH-1=47.5±2.3 kJmol-1 and ΔS-1=-129.1±0.5 JK-1mol-1. The isomerization is markedly accelerated in the presence of Lewis bases. A crossover experiment indicates that the isomer interconversion is a unimolecular process. The large negative entropies of activation suggest either the existence of a sterically congested intermediate or the participation of solvent in the isomerization process.

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References

  1. Inorg. Chem. v.28 Interrante, L. V.;Sigel, G. A.
  2. J. Chem. Soc. Chem. Commun. Phani, A. R.;Devi, G. S.;Roy, S.;Rao, V. J.
  3. Mater. v.8 Lakhotia, V.;Neumayer, D. A.
  4. Organometallics v.11 Park, J. T.;Kim, Y.;Kim, K.;Kim, Y.
  5. J. Chem. Soc., Dalton Trans. Al-Wassil, A.-A. I.;Hitchcock, P. B.;Sarisaban, S.;Smith, J. D.;Wilson, C. L.
  6. J. Chem. Soc. v.A Gosking, K.;Smith, J. D.;Wharmby, D. H. W.
  7. Bull. Chem. Soc. Jpn. v.48 Watatsuk, K.;Tanaka, T.
  8. J. Inorg. Nucl. Chem. v.26 Stevens, L. G.;Park, B.;Oliver, J. P.
  9. Organometallics Elschenbroich, C.;Salzer, A.
  10. Organometallics v.11 Kawano, Y.;Tobita, H.;Ogino, H.
  11. J. Organomet. Chem. v.306 Altbach, M. I.;Muedas, C. A.;Korswagen, R. P.;Ziegler, M. L.
  12. Chem. Mater. v.7 Cowley, A. H.;Jones, R. A.;Ekerdt, J. G.
  13. Chem. Neumayer, D. A.;Ekerdt, J. G.