Synthesis and fluxional behavior of protonated 1,3-diene complexes of ruthenium(0), osmium(0), rhodium(I), and iridium(I) containing 2,3-dimethylene-5,6,7,8-dibenzobicyclo[2.2.2]octane (ddbo, C18H14). Single-crystal X-ray study of the agostic complex [Ru(

Bennett, M. A., Pelling, S., Robertson, G. B. and Wickramasinghe, W. A. (1991) Synthesis and fluxional behavior of protonated 1,3-diene complexes of ruthenium(0), osmium(0), rhodium(I), and iridium(I) containing 2,3-dimethylene-5,6,7,8-dibenzobicyclo[2.2.2]octane (ddbo, C18H14). Single-crystal X-ray study of the agostic complex [Ru(C18H15)(η-C6H3Me 3)]PF6. Organometallics, 10 7: 2166-2172. doi:10.1021/om00053a019


Author Bennett, M. A.
Pelling, S.
Robertson, G. B.
Wickramasinghe, W. A.
Title Synthesis and fluxional behavior of protonated 1,3-diene complexes of ruthenium(0), osmium(0), rhodium(I), and iridium(I) containing 2,3-dimethylene-5,6,7,8-dibenzobicyclo[2.2.2]octane (ddbo, C18H14). Single-crystal X-ray study of the agostic complex [Ru(C18H15)(η-C6H3Me 3)]PF6
Journal name Organometallics   Check publisher's open access policy
ISSN 0276-7333
1520-6041
Publication date 1991-07
Sub-type Article (original research)
DOI 10.1021/om00053a019
Volume 10
Issue 7
Start page 2166
End page 2172
Total pages 7
Place of publication Washington, DC, United States
Publisher American Chemical Society
Language eng
Formatted abstract
The 1,3-diene 2,3-dimethylene-5,6,7,8-dibenzobicyclo[2.2.2] octane (ddbo, C18H14,6) forms complexes Ir(η-C5H5)(C18H14) (7), M(η-C5Me5)(C18H14) [M = Rh (8), Ir (9)], and M(η-1,3,5-C6H3Me3)(C18H 14) [M = Ru (10) Os (11)], which react with aqueous HPF6 or triflic acid to give fluxional monoprotonated cations [Ir(η-C5H5)(C18H15)]+ (14), [Rh(η-C5Me5)(C18H15)] + (12), [Ru(η-C6H3Me3)(C18H 15)]+ (13), and [Os,(η-C6H3Me3)(C18H 15)]+ (15). Crystals of 13·PF6 are orthorhombic, space group P212121, with a = 14.243 (2) Å b - 13.554 (2) Å, c = 12.894 (2) Å, and Z = 4. The structure was solved by heavy-atom methods and refined by least-squares analysis to R = 0.034 and Rw = 0.043 for 2020 unique observed reflections. The C18H15 moiety is bound to a (η6-mesitylene)ruthenium unit through a η3-enyl linkage [Ru-C(1) = 2.180 (8) Å, Ru-C(2) = 2.196 (7) Å, Ru-C(17) = 2.148 (7) Å] and a two-electron, three-center interaction Ru-H(18C)-C(18) to the terminal methyl group of the butenyl moiety [Ru-C(18) = 2.357 (9) Å, C(18)-H(18C) = 0.98 (8) Å, Ru-H(18C) = 1.81 (8) Å, 〈C(17)-C(18)-H(18C) = 108 (5)°, 〈C(18)-H(18C)-Ru = 112 (6)°]. The NMR (1H, 13C) spectra of the rhodium complex 12 at -60°C are consistent with a similar ground-state agostic η3-methallyl structure, but unexpectedly, the 1H NMR spectrum of 13 at -100°C resembles that expected for a hydrido (1,3-diene) structure. It is suggested that in 13 reversible C-H bond cleavage occurs more easily than M-H bond cleavage, whereas 12 shows the more usual reverse behavior. The NMR and IR spectra of 14 show this complex to have a hydrido 1,3-diene structure; the same is probably true for 15, although a η3-methallyl structure with a strong agostic interaction cannot be excluded. Treatment of 13 and 15 with tert-butyl isocyanide causes irreversible hydride transfer to ddbo, giving [M(η-C6H3Me3)(C18H 15)(CN-t-Bu)]PF6 [M = Ru (17), Os (16)].
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: National Research Centre for Environmental Toxicology Publications
 
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