Pincer complexes are useful tools for organic synthesis. Their high stability and easy functionalization have allowed the development of novel catalytic systems that have had a tremendous impact in different areas of chemistry. Thus, catalytic reactions are nowadays a fundamental part of several synthetic routes, as they allow “greener” procedures with high atom efficiency. In this context, pincer complexes have contributed to the establishment of novel and efficient catalytic reactions. Thus, herein we summarize the most recent relevant advances involving pincer complexes as catalysts.

A series of iridium complexes containing phenanthro[4,5--abc]phenazino[11,12--d]imidazol--2--ylidene and ace-- [11,12--d]imidazol--2--ylidene ligands have been obtained and fully characterized. These com--plexes display highly extended polyaromatic systems attached to the backbone of the N--heterocyclic carbene. The pres--ence of this extended polyaromatic system makes the electron--donating character of these ligands sensitive to the pres--ence of π--stacking additives, such as pyrene and hexafluorobenzene. The computational studies predict that the addition of pyrene affords an increase of the electron--donating character of the polyaromatic ligand (TEP decreases), while the addition of hexafluorobenzene has the opposite effect (TEP increases). This prediction is experimentally corroborated by IR spectroscopy, by measuring the shift of the CO stretching bands of a series of IrCl(NHC)(CO) 2 complexes, where NHC is the N--heterocyclic carbene ligand with the polyaromatic system. Finally, the energy of the π--stacking interaction of one of the key Ir(I) complexes with pyrene and hexafluorobenzene has been estimated by using the Benesi--Hildebrand treat--ment, based on the δ--shifts observed by 1 H NMR spectroscopy.

Registro de acceso restringido Este recurso no está disponible en acceso abierto por política de la editorial. No obstante, se puede acceder al texto completo desde la Universitat Jaume I o si el usuario cuenta con suscripción. Registre d'accés restringit Aquest recurs no està disponible en accés obert per política de l'editorial. No obstant això, es pot accedir al text complet des de la Universitat Jaume I o si l'usuari compta amb subscripció. Restricted access item This item isn't open access because of publisher's policy. The full--text version is only available from Jaume I University or if the user has a running suscription to the publisher's contents.

No abstract

No abstract

Registro de acceso restringido Este recurso no está disponible en acceso abierto por política de la editorial. No obstante, se puede acceder al texto completo desde la Universitat Jaume I o si el usuario cuenta con suscripción. Registre d'accés restringit Aquest recurs no està disponible en accés obert per política de l'editorial. No obstant això, es pot accedir al text complet des de la Universitat Jaume I o si l'usuari compta amb subscripció. Restricted access item This item isn't open access because of publisher's policy. The full--text version is only available from Jaume I University or if the user has a running suscription to the publisher's contents.

Oxidant-free Au-catalyzed reactions are emerging as a new synthetic tool for innovative organic transformations. Still, a deeper mechanistic understanding is needed for a rational design of these processes. Here we...

A Janus--type di--NHC ligand based on a quinoxalinophenanthrophenazine core has been obtained and coordinated to iridium. The electronic properties of the ligand have been determined based on the evaluation of the TEP values. The new ligand disposes the two metals at a distance of 22.4 Å, significantly longer than any of the re--lated ligands reported so far.