Steric and electronic factors in rollover C−H bond activation of substituted 2,2′-bipyridines, mediated by platinum(II), have been investigated by comparing the influence of two substituents, CH3 and CF3, on the progress of the reaction. The substituents were chosen to have similar steric hindrance but different electronic effects and were placed in position 6 (i.e., near one of the nitrogen atoms) or in position 5, which allows, in part, electronic and steric influence to be distinguished. The ligands studied, 6-methyl-2,2′-bipyridine, 5-methyl-2,2′-bipyridine, 6-trifluoromethyl-2,2′-bipyridine, and 5-trifluoromethyl- 2,2′-bipyridine, were compared to unsubstituted 2,2′-bipyridine in the reaction with the electron-rich complex [Pt(Me)2(DMSO)2]. The electron-withdrawing CF3 group was found to have a significant effect in accelerating the cyclometalation reaction. The substituent in position 6 influences the stability of the intermediate adduct [Pt(N,N)(Me)2] (N,N = chelated bipyridine), as indicated by density functional theory calculations. The steric hindrance of substituted bipyridines was also evaluated by defining and measuring the angle ζ in [Pt(N,N)(Me)2] adducts. The presence of a substituent in position 6 causes destabilization of the adduct, acceleration of the cyclometalation reaction, and regioselectivity of C−H bond activation.

Electronic and steric effects in rollover C-H bond activation / Maidich, Luca; Dettori, G; Stoccoro, Sergio; Cinellu, Maria Agostina; Rourke, Jp; Zucca, Antonio. - In: ORGANOMETALLICS. - ISSN 0276-7333. - 34:5(2015), pp. 817-828. [10.1021/om500681u]

Electronic and steric effects in rollover C-H bond activation

MAIDICH, Luca;STOCCORO, Sergio;CINELLU, Maria Agostina;ZUCCA, Antonio
2015-01-01

Abstract

Steric and electronic factors in rollover C−H bond activation of substituted 2,2′-bipyridines, mediated by platinum(II), have been investigated by comparing the influence of two substituents, CH3 and CF3, on the progress of the reaction. The substituents were chosen to have similar steric hindrance but different electronic effects and were placed in position 6 (i.e., near one of the nitrogen atoms) or in position 5, which allows, in part, electronic and steric influence to be distinguished. The ligands studied, 6-methyl-2,2′-bipyridine, 5-methyl-2,2′-bipyridine, 6-trifluoromethyl-2,2′-bipyridine, and 5-trifluoromethyl- 2,2′-bipyridine, were compared to unsubstituted 2,2′-bipyridine in the reaction with the electron-rich complex [Pt(Me)2(DMSO)2]. The electron-withdrawing CF3 group was found to have a significant effect in accelerating the cyclometalation reaction. The substituent in position 6 influences the stability of the intermediate adduct [Pt(N,N)(Me)2] (N,N = chelated bipyridine), as indicated by density functional theory calculations. The steric hindrance of substituted bipyridines was also evaluated by defining and measuring the angle ζ in [Pt(N,N)(Me)2] adducts. The presence of a substituent in position 6 causes destabilization of the adduct, acceleration of the cyclometalation reaction, and regioselectivity of C−H bond activation.
2015
Electronic and steric effects in rollover C-H bond activation / Maidich, Luca; Dettori, G; Stoccoro, Sergio; Cinellu, Maria Agostina; Rourke, Jp; Zucca, Antonio. - In: ORGANOMETALLICS. - ISSN 0276-7333. - 34:5(2015), pp. 817-828. [10.1021/om500681u]
File in questo prodotto:
File Dimensione Formato  
Electronic and steric effects in rollover C-H bond activation.pdf

solo utenti autorizzati

Tipologia: Documento in Post-print (versione referata ma senza layout editoriale)
Licenza: Non pubblico (Accesso privato/ristretto)
Dimensione 2.04 MB
Formato Adobe PDF
2.04 MB Adobe PDF   Visualizza/Apri   Richiedi una copia

I documenti in IRIS 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/11388/46466
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 35
  • ???jsp.display-item.citation.isi??? 35
social impact