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Pregled bibliografske jedinice broj: 238553

Časopis

Autori: Egle, Ian; Gabelica, Vesna; Kresge, Alexander J., Tidwell, Thomas T.
Naslov: The acid-catalyzed demetalation of 1-(tri-n-butylstannyl)-2-phenylethyne. A surprisingly small beta-stannyl effect
( The acid-catalyzed demetalation of 1-(tri-n-butylstannyl)-2-phenylethyne. A surprisingly small beta-stannyl effect )
Izvornik: Canadian Journal of Chemistry (0008-4042) 74 (1996); 1366-1368
Vrsta rada: članak
Ključne riječi: beta-stannyl effect; beta-silyl effect; carbocation stabilization; protodemetalation
( beta-stannyl effect; beta-silyl effect; carbocation stabilization; protodemetalation )
Sažetak:
Rates of conversion of 1-(tri-n-butylstannyl)-2-phenylethyne to phenylethyne in H2O and D2O solutions of perchloric acid were found to be proportional to acid concentration, giving the hydroniuj ion rate constant kH+=1.85x10-2M-1s-1 and the isotope effect kH+/kD+=3.10. Magnitude of this isotope effect suggests that the reaction occurs by rate-determining hydron transfer to the substrate, producing a vinyl carbocation ; this carbocation then loses its tributhylstannyl group, giving phenylacetylene as the only detectable aromatic product. The hydronium ion rate constant, when compared to the rates of protonation of phenylethyne and 1-(trimethylsilyl)-2-phenlyethyne, gives a beta-stannyl stabilizing effect of delta Δ G≠ = 6.6 kcalmol-1 and a differential beta-stannyl/beta-silyl effect of delta Δ G≠ = 3.2 kcalmol-1. These stabilizations are very much smaller than proviously reported beta-stannyl effects. Possible reasons for the difference are suggested.
Izvorni jezik: eng
Rad je indeksiran u
bazama podataka:
Current Contents Connect (CCC)
Scopus
SCI-EXP, SSCI i/ili A&HCI
Kategorija: Znanstveni
Znanstvena područja:
Kemija
URL cjelovitog teksta:
Google Scholar: The acid-catalyzed demetalation of 1-(tri-n-butylstannyl)-2-phenylethyne. A surprisingly small beta-stannyl effect



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