Heterobimetallic Complexes Bridged by Imidazol{[4,5-f][1,10]-phenanthrolin}-2-ylidene: Synthesis and Catalytic Activity in Tandem Reactions
ORGANOMETALLICS, vol.38, no.2, pp.593-601, 2019 (SCI-Expanded, Scopus)
- Publication Type: Article / Article
- Volume: 38 Issue: 2
- Publication Date: 2019
- Doi Number: 10.1021/acs.organomet.8b00882
- Journal Name: ORGANOMETALLICS
- Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
- Page Numbers: pp.593-601
- Dokuz Eylül University Affiliated: Yes
Abstract
A series of monometallic complexes obtained by metalation of the phenanthrolin donor in 1,3-dibutyl-1H-imidazol[4,5-f][1,10]phenanthrolin}ium hexafluorophospate 1 (M = Pd 2, Ru 3, Ir 4) have been prepared. Subsequently, the imidazolium moiety of complexes 2-4 was metalated with M', leading to the heterobimetallic phenanthroline/NHC complexes (M/M' = Pd/Rh 5, Pd/Ir 6, Pd/Ru 7, Ru/Pd 8, Ir/Pd 9) and the homobimetallic complex (M/M' = Ir/Ir 10). The new complexes were characterized by elemental analysis, FTIR, UV-vis, and NMR spectroscopy. The molecular structures of the heterobimetallic complexes 5 and 6 were determined by X-ray diffraction studies. The catalytic activity of the heterobimetallic complexes 5-9 were tested in selected tandem reactions (dehalogenation/transfer hydrogenation and Suzuki-Miyaura coupling/transfer hydrogenation). It was found that the M/M' heterobimetallic complexes display higher catalytic activities when compared to equimolar mixtures of the mononuclear complexes M and M', thus indicating that an increase in the number of metal atoms in one complex leads to an increased activity in the tandem reactions.