N-heterocyclic carbenes bearing a naphthyl substituent and their metal complexes: synthesis, structure, and application in catalytic transfer hydrogenation

Authors : Aylin ATİK, Lütfiye Gök PEZÜK, Hayati TÜRKMEN

Pages : 29-39

View : 14 | Download : 12

Publication Date : 0000-00-00

Article Type : Research Paper

Abstract :A series of unsymmetrical imidazolinium bromides insert ignore into journalissuearticles values(3a-d); bearing naphthyl and benzyl groups insert ignore into journalissuearticles values(R` = CH$_{2}$C$_{6}$H$_{2}$insert ignore into journalissuearticles values(CH$_{3});_{3}$-2,4,6 insert ignore into journalissuearticles values(a);; CH$_{2}$C$_{6}$Hinsert ignore into journalissuearticles values(CH$_{3});_{4}$-2,3,5,6 insert ignore into journalissuearticles values(b);; CH$_{2}$C$_{6}$insert ignore into journalissuearticles values(CH$_{3});_{5}$ insert ignore into journalissuearticles values(c);; CH$_{2}$C$_{6}$F$_{5\, }$insert ignore into journalissuearticles values(d);); at the N$^{1}$ and N$^{3}$ positions were successfully synthesized. [RuCl$_{2}$insert ignore into journalissuearticles values(NHC);insert ignore into journalissuearticles values($p$-cymene);] insert ignore into journalissuearticles values(NHC= N-heterocyclic carbene); complexes insert ignore into journalissuearticles values(4a-d); were prepared by the reaction of [RuCl$_{2}insert ignore into journalissuearticles values(p$-cymene);]$_{2}$ with imidazolinium salts insert ignore into journalissuearticles values(3a-d);. The new salts insert ignore into journalissuearticles values(3a-d); and their rutheniuminsert ignore into journalissuearticles values(II); complexes insert ignore into journalissuearticles values(4a-d); were characterized by $^{1}$H, $^{13}$C, $^{19}$F NMR, and elemental analysis. The rutheniuminsert ignore into journalissuearticles values(II); complexes insert ignore into journalissuearticles values(4a-d); were employed as catalysts for the transfer hydrogenation insert ignore into journalissuearticles values(TH); of ketones in the presence of KOH using 2-propanol as a hydrogen source and the results were compared. The best results in the transfer hydrogenation of ketones were obtained with 4b. [MClinsert ignore into journalissuearticles values(NHC);L] insert ignore into journalissuearticles values(M = Ir, L = Cp$^{\ast });$ insert ignore into journalissuearticles values(5b);, cod insert ignore into journalissuearticles values(6b);; M = Rh, L= Cp$^{\ast}$ insert ignore into journalissuearticles values(5b`);, and cod insert ignore into journalissuearticles values(6b`); complexes were prepared and investigated in the TH of ketones. The reactivity of Rh complexes in comparison to those of Ir also appears to be somewhat better. The catalysis appears to be homogeneous.
Keywords : Arene ruthenium II, complexes, N heterocyclic carbene, transfer hydrogenation, naphthyl substituent