We have synthesized several novel palladium(0) olefin complexes stabilized by strong σ-donating bis-chelating carbene ligands characterized by one or two CH2spacers and electron-withdrawing olefins. Although it appears obvious that the σ-donating carbenes and electron-withdrawing olefins should cooperate in the stabilization of the ensuing complexes, the limit of their coexistence was not hitherto clear. On the basis of previously measured stabilizing capability of the olefins toward Pd(0) complexes we were able to synthesize ten complexes (nine new and one synthesized by a different protocol from that of the literature). The less electron-withdrawing olefin capable of stabilizing the complex was dimethylfumarate. However, the most interesting results were obtained with the (Z)-1,2-bis(p-tolylsulfonyl)ethene (cis-sulf) which instantly isomerizes upon coordination and in the case of the derivative bearing the olefin tetramethyl ethene-1,1,2,2-tetracarboxylate (tmetc) whose decomposition in CD2Cl2yields the saturated tetramethyl ethane-1,1,2,2-tetracarboxylate (D2). The solid-state structure of the complex 4d bearing the bis-carbene 1,1′-dibenzyl-3,3′methylenediimidazol-2,2′-diylidene and the olefin (E)-1,2-bis(p-tolylsulfonyl)ethene (trans-sulf) was also determined.

Synthesis and characterization of novel olefin complexes of palladium(0) with chelating bis(N-heterocyclic carbenes) as spectator ligands

Scattolin, T.;Canovese, L.
;
Visentin, F.;Santo, C.;
2018-01-01

Abstract

We have synthesized several novel palladium(0) olefin complexes stabilized by strong σ-donating bis-chelating carbene ligands characterized by one or two CH2spacers and electron-withdrawing olefins. Although it appears obvious that the σ-donating carbenes and electron-withdrawing olefins should cooperate in the stabilization of the ensuing complexes, the limit of their coexistence was not hitherto clear. On the basis of previously measured stabilizing capability of the olefins toward Pd(0) complexes we were able to synthesize ten complexes (nine new and one synthesized by a different protocol from that of the literature). The less electron-withdrawing olefin capable of stabilizing the complex was dimethylfumarate. However, the most interesting results were obtained with the (Z)-1,2-bis(p-tolylsulfonyl)ethene (cis-sulf) which instantly isomerizes upon coordination and in the case of the derivative bearing the olefin tetramethyl ethene-1,1,2,2-tetracarboxylate (tmetc) whose decomposition in CD2Cl2yields the saturated tetramethyl ethane-1,1,2,2-tetracarboxylate (D2). The solid-state structure of the complex 4d bearing the bis-carbene 1,1′-dibenzyl-3,3′methylenediimidazol-2,2′-diylidene and the olefin (E)-1,2-bis(p-tolylsulfonyl)ethene (trans-sulf) was also determined.
File in questo prodotto:
File Dimensione Formato  
poly2018 2°.pdf

accesso aperto

Tipologia: Documento in Post-print
Licenza: Accesso gratuito (solo visione)
Dimensione 985.03 kB
Formato Adobe PDF
985.03 kB Adobe PDF Visualizza/Apri

I documenti in ARCA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10278/3703203
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 10
  • ???jsp.display-item.citation.isi??? 10
social impact