Webbläsaren som du använder stöds inte av denna webbplats. Alla versioner av Internet Explorer stöds inte längre, av oss eller Microsoft (läs mer här: * https://www.microsoft.com/en-us/microsoft-365/windows/end-of-ie-support).

Var god och använd en modern webbläsare för att ta del av denna webbplats, som t.ex. nyaste versioner av Edge, Chrome, Firefox eller Safari osv.

Pseudo-rotation mechanism for fast olefin exchange and substitution processes at orthometalated C,N-complexes of platinum(II)

In English

Författare

Summary, in English

Bridge splitting in chloroform of the orthometalated chloro-bridged complex [Pt(mu-Cl)(2-Me2NCH2C6H4)](2) (1), with ethene, cyclooctene, allyl alcohol and phosphine according to 1 + 2L --> 2 [PtCl(2-Me2NCH2C6H4)(L)], where L = C2H4 (3a), C8H14, (3b), CH2CHCH2OH (3c), and PPh3 (4a and 4b) gives monomeric species with L coordinated trans or cis to aryl. With olefins the thermodynamically stable isomer with L coordinated cis to aryl is formed directly without an observable intermediate. With phosphine and pyridine, the kinetically controlled trans-product isomerizes slowly to the more stable cis-isomer. Bridge splitting by olefins is slow and first-order in 1 and L, with largely negative DeltaS(double dagger). Substitution of ethene cis to aryl by cyclooctene and allyl alcohol to form 3b and 3c, and substitution of cot from 3b by allyl alcohol to form 3c are first order in olefin and complex, ca. six orders of magnitude faster than bridge cleavage due to a large decrease in DeltaH(double dagger), and with largely negative DeltaS(double dagger). Cyclooctene exchange at 3b is first-order with respect to free cyclooctene and platinum complex. All experimental data for olefin substitution and exchange are compatible with a concerted substitution/isomerization process via a turnstile twist pseudo-rotation in a short-lived labile five-coordinated intermediate, involving initial attack on the labile coordination position trans to the sigma-bonded aryl. Bridge-cleavage reactions of the analogous bridged complexes occur similarly, but are much slower because of their ground-state stabilization and steric hindrance.

Publiceringsår

2004

Språk

Engelska

Sidor

3662-3668

Publikation/Tidskrift/Serie

Dalton Transactions

Issue

21

Dokumenttyp

Artikel i tidskrift

Förlag

Royal Society of Chemistry

Ämne

  • Inorganic Chemistry

Nyckelord

  • Olefin exchange
  • Fast reactions
  • Pseudo-rotation mechanism

Status

Published

ISBN/ISSN/Övrigt

  • ISSN: 1477-9234