Synthesis and structural characterization of ruthenium(II) complexes bearing phosphine-pyrazolyl based tripod ligands

Exceptionally Efficient Unsymmetrical Ruthenium(II) NNN Complex Catalysts Bearing a Pyridyl-Based Pyrazolyl−Imidazolyl Ligand for Transfer Hydrogenation of Ketones

“…In our case, a 2,6-bis(3,5-dimethylpyrazol-1-yl)pyridine-supported Ru(II) complex can efficiently catalyze the TH reactions of ketones in 2-propanol, achieving a final TOF value of 6000 h −1 at 82 °C. During our ongoing investigation on new polydentate N-heterocyclic ligands, we have become interested in the construction of unsymmetrical planar pyridyl-based 2,6-(mixed N-heterocycle) ligands in which the mixed N-heterocycles themselves are usually bestowed with poor capability to coordinate late transition metals and the tridentate ligand often exhibits some hemilability to the metal center of the complex, resulting in a highly active transition-metal complex catalyst. Herein, we report the synthesis of a new class of pyridyl-based pyrazolyl−imidazolyl ligands and the exceptionally high catalytic activity of their Ru(II) complexes in the TH of ketones.…”

Preparation, characterization, and catalytic properties of ruthenium nitrosyl complexes with polypyrazolylmethane ligands

“…Most of the reported ruthenium catalysts are based on phosphine-containing ligands. Recently ruthenium complexes supported by polydentate nitrogen ligands have been found to be very effective transfer hydrogenation catalyst to reduction of ketone [17][18][19][20][21]. To the best of our knowledge, there has been no report of ruthenium nitrosyl complexes used in this particular transformation to date.…”

Synthesis and structural characterization of (CH2)n-bridged indenyl-pyrazoles and their cyclopentadienyl nickel(II) complexes

“…Although a variety of bridged cyclopentadienyl ligands have been developed and the emerging importance of replacing cyclopentadienyl groups with their heterocyclic analogues such as g 5 -pyrazolato moieties has been aroused interest [9][10][11], a few reports have been reported on organometallic complexes bearing bridged indenyl-pyrazolato ligands [24,25,27]. During our ongoing investigation on pyrazole and pyrazolato chemistry [31][32][33][34], we have become interested in understanding whether the bridged indenyl-pyrazolato ligands display the same diversity in coordination chemistry as that of the non-functionalized pyrazolato ligands to late transition metals. Herein, we wish to describe synthesis and structural characterization of a new class of (CH 2 ) n -bridged indenyl-pyrazoles and their trimetallic and dimetallic cyclopentadienyl nickel(II) pyrazolato complexes.…”