Simple synthesis of [Ru(CO₃)(NHC)(p-cymene)] complexes and their use in transfer hydrogenation catalysis

Abstract

A novel, efficient and facile protocol for the synthesis of a series of [Ru(NHC)(CO3)(p-cymene)] complexes is reported. This family of Ru-NHC complexes was obtained from imidazol(in)ium tetrafluoroborate or imidazolium hydrogen...

Imidazolium-Based N-Heterocyclic Carbenes (NHCs) and Metal-Mediated Catalysis

“…Hydrogenation [85], transfer hydrogenation [86], hydrosilylation [87], hydroboration, and hydroamination [88] are the different types of NHC-transition metal catalyzed addition reactions. A brief outline of the various addition reactions catalyzed by NHC-transition metal complexes is summarized in Figure 19.…”

Base-free synthesis of benchtop stable Ru(iii)–NHC complexes from RuCl3·3H2O and their use as precursors for Ru(ii)–NHC complexes

“…8 These Ru-NHC complexes have found applications from homogeneous catalysis [9][10][11][12][13][14][15] to therapeutic drugs, 16,17 olefin metathesis reactions [18][19][20] and solar cells (DSSCs). [21][22][23] In general, the synthesis of Ru-NHC complexes involves one of the common Ru metal precursors Ru(Cl)2(PPh3)3, 24 [Ru(Cl)2(p-cymene)]2, 25 [Ru(Cl)2(CO)2]n, 26 Ru II (Cl)2(DMSO)4, 27 [Ru(Cl)2(COD)]n, 28 etc., where one or more of the ligands are replaced with the in situ generated NHC ligands. Ru-precursor complexes play a significant role in the development of new Ru-complexes.…”

“…[30][31][32] Involvement of base in such reactions has its shortcomings, namely, the limited or no use of aerobic conditions, less scope to employ green solvents, and possibility of forming undesired side products. 33 Nolan and coworkers have recently developed a "weak base" route 25,[33][34][35] for generating NHC-metal complexes. The simple "weak base" route has been described as a cost-effective and environmentally benign approach which can be extended further with various metals for NHC-based complexes.…”

Base-free synthesis of benchtop stable Ru(III)-NHC complexes from RuCl3·3H2O and their use as precursors for Ru(II)-NHC complexes

“…8 These Ru-NHC complexes have found applications from homogeneous catalysis [9][10][11][12][13][14][15] to therapeutic drugs, 16,17 olefin metathesis reactions [18][19][20] and solar cells (DSSCs). [21][22][23] In general, the synthesis of Ru-NHC complexes involves one of the common Ru metal precursors Ru(Cl)2(PPh3)3, 24 [Ru(Cl)2(p-cymene)]2, 25 [Ru(Cl)2(CO)2]n, 26 Ru II (Cl)2(DMSO)4, 27 [Ru(Cl)2(COD)]n, 28 etc., where one or more of the ligands are replaced with the in situ generated NHC ligands. Ru-precursor complexes play a significant role in the development of new Ru-complexes.…”