Rhodium and iridium β-diiminate complexes - Olefin hydrogenation step by step

European Journal of Inorganic Chemistry

Volumn , Issue 4, 2000, Pages 753-769

  Budzelaar, Peter H M ^a   Moonen, Nicolle N P ^a   De Gelder, René ^a   Smits, Jan M M ^a   Gal, Anton W ^a  

^a RADBOUD UNIVERSITY NIJMEGEN   (Netherlands)

Author keywords

Hydrides; Hydrogenation; Iridium; Isomerization; Rhodium

Indexed keywords

HYDROGENATION; IRIDIUM COMPOUNDS; ISOMERIZATION; ISOMERS; LIGANDS; OLEFINS; RHODIUM COMPOUNDS;

COORDINATION NUMBER; COORDINATIVE UNSATURATIONS; CYCLOOCTENE; DIIMINATE; INTRAMOLECULAR COORDINATION; IR COMPLEXES; ISOMERISATION; LOW COORDINATION; OLEFIN HYDROGENATION; RH COMPLEXES;

HYDRIDES;

ALKENE; IRIDIUM COMPLEX; RHODIUM COMPLEX;

ARTICLE; CATALYSIS; COMPLEX FORMATION; CRYSTAL STRUCTURE; HYDROGENATION; ISOMERISM; NUCLEAR MAGNETIC RESONANCE; TEMPERATURE; X RAY CRYSTALLOGRAPHY;

EID: 0034049651     PISSN: 14341948     EISSN: None     Source Type: Journal    
DOI: 10.1002/(sici)1099-0682(200004)2000:4<753::aid-ejic753>3.3.co;2-m     Document Type: Article

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4. Most of these complexes are chloro-bridged dimers in the solid state, but dissociate in solution. See, e.g. [3a] H. L. M. van Gaal, F. G. Moers, J. J. Steggerda, J. Organomet. Chem. 1974, 65, C43; H. L. M. van Gaal, F. L. A. van den Bekerom, J. P. J. Verlaan, J. Organomet. Chem. 1976, 114, C35; H. L. M. van Gaal, F. L. A. van den Bekerom, J. Organomet. Chem. 1977, 134, 237; C. Busetto, A. d'Alfonso, F. Maspero, G. Perego, A. Zazzetta, J. Chem. Soc., Dalton Trans. 1977, 1828; P. R. Hoffman, T. Yoshida, T. Okano, S. Otsuka, J. A. Ibers, Inorg. Chem. 1976, 15, 2462; T. Yoshida, T. Okano, D. L. Thorn, T. H. Tulip, S. Otsuka, J. A. Ibers, J. Organomet. Chem. 1979, 181, 183; P. Binger, J. Haas, G. Glaser, R. Goddard, C. Krüger, Chem. Ber. 1994, 727, 1927.
5. Most of these complexes are chloro-bridged dimers in the solid state, but dissociate in solution. See, e.g. [3a] H. L. M. van Gaal, F. G. Moers, J. J. Steggerda, J. Organomet. Chem. 1974, 65, C43; H. L. M. van Gaal, F. L. A. van den Bekerom, J. P. J. Verlaan, J. Organomet. Chem. 1976, 114, C35; H. L. M. van Gaal, F. L. A. van den Bekerom, J. Organomet. Chem. 1977, 134, 237; C. Busetto, A. d'Alfonso, F. Maspero, G. Perego, A. Zazzetta, J. Chem. Soc., Dalton Trans. 1977, 1828; P. R. Hoffman, T. Yoshida, T. Okano, S. Otsuka, J. A. Ibers, Inorg. Chem. 1976, 15, 2462; T. Yoshida, T. Okano, D. L. Thorn, T. H. Tulip, S. Otsuka, J. A. Ibers, J. Organomet. Chem. 1979, 181, 183; P. Binger, J. Haas, G. Glaser, R. Goddard, C. Krüger, Chem. Ber. 1994, 727, 1927.
6. Most of these complexes are chloro-bridged dimers in the solid state, but dissociate in solution. See, e.g. [3a] H. L. M. van Gaal, F. G. Moers, J. J. Steggerda, J. Organomet. Chem. 1974, 65, C43; H. L. M. van Gaal, F. L. A. van den Bekerom, J. P. J. Verlaan, J. Organomet. Chem. 1976, 114, C35; H. L. M. van Gaal, F. L. A. van den Bekerom, J. Organomet. Chem. 1977, 134, 237; C. Busetto, A. d'Alfonso, F. Maspero, G. Perego, A. Zazzetta, J. Chem. Soc., Dalton Trans. 1977, 1828; P. R. Hoffman, T. Yoshida, T. Okano, S. Otsuka, J. A. Ibers, Inorg. Chem. 1976, 15, 2462; T. Yoshida, T. Okano, D. L. Thorn, T. H. Tulip, S. Otsuka, J. A. Ibers, J. Organomet. Chem. 1979, 181, 183; P. Binger, J. Haas, G. Glaser, R. Goddard, C. Krüger, Chem. Ber. 1994, 727, 1927.
7. Most of these complexes are chloro-bridged dimers in the solid state, but dissociate in solution. See, e.g. [3a] H. L. M. van Gaal, F. G. Moers, J. J. Steggerda, J. Organomet. Chem. 1974, 65, C43; H. L. M. van Gaal, F. L. A. van den Bekerom, J. P. J. Verlaan, J. Organomet. Chem. 1976, 114, C35; H. L. M. van Gaal, F. L. A. van den Bekerom, J. Organomet. Chem. 1977, 134, 237; C. Busetto, A. d'Alfonso, F. Maspero, G. Perego, A. Zazzetta, J. Chem. Soc., Dalton Trans. 1977, 1828; P. R. Hoffman, T. Yoshida, T. Okano, S. Otsuka, J. A. Ibers, Inorg. Chem. 1976, 15, 2462; T. Yoshida, T. Okano, D. L. Thorn, T. H. Tulip, S. Otsuka, J. A. Ibers, J. Organomet. Chem. 1979, 181, 183; P. Binger, J. Haas, G. Glaser, R. Goddard, C. Krüger, Chem. Ber. 1994, 727, 1927.
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15. A distorted T-shape and easy movement of the chlorine atom in three-coordinate bis(phosphane)RhCl complexes has been predicted on the basis of extended-Hückel calculations; see ref. [3b].
16. 8]toluene (down to -40°C) were virtually identical, indicating the absence of significant THF coordination. However, the presence of some arene complexes (to be described in a future paper) in the toluene spectra made interpretation more difficult in these cases.
17. The allyl hydride mechanism is one of the accepted mechanisms for olefin isomerization. However, only a few examples of rapid equilibration between the two structures have been reported: J. W. Byrne, H. U. Blaser, J. A. Osborn, J. Am. Chem. Soc. 1975, 97, 3871; H. Bönneman, Angew. Chem. 1970, 82, 699 (Int. Ed. Engl. 1970, 9, 736). Decomposition of rhodium(III) allyl hydride complexes to give free olefin has also been demonstrated: J. F. Nixon, B. Wilkins, J. Organomet. Chem. 1972, 44, C25; 1974, 80, 129. For an example of rapid allylic C-H activation at Ir, see R. Dorta, A. Togni, Organometallics 1998, 17, 5441.
18. The allyl hydride mechanism is one of the accepted mechanisms for olefin isomerization. However, only a few examples of rapid equilibration between the two structures have been reported: J. W. Byrne, H. U. Blaser, J. A. Osborn, J. Am. Chem. Soc. 1975, 97, 3871; H. Bönneman, Angew. Chem. 1970, 82, 699 (Int. Ed. Engl. 1970, 9, 736). Decomposition of rhodium(III) allyl hydride complexes to give free olefin has also been demonstrated: J. F. Nixon, B. Wilkins, J. Organomet. Chem. 1972, 44, C25; 1974, 80, 129. For an example of rapid allylic C-H activation at Ir, see R. Dorta, A. Togni, Organometallics 1998, 17, 5441.
19. The allyl hydride mechanism is one of the accepted mechanisms for olefin isomerization. However, only a few examples of rapid equilibration between the two structures have been reported: J. W. Byrne, H. U. Blaser, J. A. Osborn, J. Am. Chem. Soc. 1975, 97, 3871; H. Bönneman, Angew. Chem. 1970, 82, 699 (Int. Ed. Engl. 1970, 9, 736). Decomposition of rhodium(III) allyl hydride complexes to give free olefin has also been demonstrated: J. F. Nixon, B. Wilkins, J. Organomet. Chem. 1972, 44, C25; 1974, 80, 129. For an example of rapid allylic C-H activation at Ir, see R. Dorta, A. Togni, Organometallics 1998, 17, 5441.
20. The allyl hydride mechanism is one of the accepted mechanisms for olefin isomerization. However, only a few examples of rapid equilibration between the two structures have been reported: J. W. Byrne, H. U. Blaser, J. A. Osborn, J. Am. Chem. Soc. 1975, 97, 3871; H. Bönneman, Angew. Chem. 1970, 82, 699 (Int. Ed. Engl. 1970, 9, 736). Decomposition of rhodium(III) allyl hydride complexes to give free olefin has also been demonstrated: J. F. Nixon, B. Wilkins, J. Organomet. Chem. 1972, 44, C25; 1974, 80, 129. For an example of rapid allylic C-H activation at Ir, see R. Dorta, A. Togni, Organometallics 1998, 17, 5441.
21. The allyl hydride mechanism is one of the accepted mechanisms for olefin isomerization. However, only a few examples of rapid equilibration between the two structures have been reported: J. W. Byrne, H. U. Blaser, J. A. Osborn, J. Am. Chem. Soc. 1975, 97, 3871; H. Bönneman, Angew. Chem. 1970, 82, 699 (Int. Ed. Engl. 1970, 9, 736). Decomposition of rhodium(III) allyl hydride complexes to give free olefin has also been demonstrated: J. F. Nixon, B. Wilkins, J. Organomet. Chem. 1972, 44, C25; 1974, 80, 129. For an example of rapid allylic C-H activation at Ir, see R. Dorta, A. Togni, Organometallics 1998, 17, 5441.
22. The allyl hydride mechanism is one of the accepted mechanisms for olefin isomerization. However, only a few examples of rapid equilibration between the two structures have been reported: J. W. Byrne, H. U. Blaser, J. A. Osborn, J. Am. Chem. Soc. 1975, 97, 3871; H. Bönneman, Angew. Chem. 1970, 82, 699 (Int. Ed. Engl. 1970, 9, 736). Decomposition of rhodium(III) allyl hydride complexes to give free olefin has also been demonstrated: J. F. Nixon, B. Wilkins, J. Organomet. Chem. 1972, 44, C25; 1974, 80, 129. For an example of rapid allylic C-H activation at Ir, see R. Dorta, A. Togni, Organometallics 1998, 17, 5441.
23. Reductive elimination from palladiutn(II) and platinum(II) allyl hydrides has been studied computationally: S. Sakaki, H. Satoh, H. Shono, Y. Ujino, Organometallics 1996, 15, 1713.
24. [2] gives a smaller energy difference and a lower barrier. Apart from correlation treatment, sources of errors could be the basis set (not very large) and the lack of an explicit treatment of direct relativistic effects on the valence electrons.
25. Steric effects are expected to favor the allyl hydride structure over the olefin complex because of the more "central" position of the allyl group relative to the diiminate aryl groups.
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27. Formation of iridium allyl hydrides from olefin precursors has been reported previously. See, e.g. R. S. Tanke, R. H. Crabtree, Inorg. Chem. 1989, 28, 3444; Y. Alvarado, O. Boutry, E. Gutiérrez, A. Monge, M. C. Nicasio, M. L. Poveda, P. J. Pérez, C. Ruiz, C. Bianchini, E. Carmona, Chem. Eur. J. 1997, 3, 860.
28. MeIr(H)(cyclooctenyl) decomposes rapidly on heating in solution, hence we could not verify the onset of dynamic behavior expected at higher temperatures.
29. 2] described in the section on hydrogenation.
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35. 2 out"). These observations support our hypothesis that the agostic "bond" is not strong even in the NBE complex. The attractive force is rather weak, but since there is no repulsive force and the olefin is pre-organized, a close Rh-H contact still results.
36. 1(min) studies were not carried out.
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