Chemistry is an experimental science, and the best way to enjoy it and learn about it is performing experiments. COA of Formula: C17H14O. Introducing a new discovery about 538-58-9, Name is 1,5-Diphenylpenta-1,4-dien-3-one
Modular Pincer-type Pyridylidene Amide Ruthenium(II) Complexes for Efficient Transfer Hydrogenation Catalysis
A set of bench-stable ruthenium complexes with new N,N,N-tridentate coordinating pincer-type pyridyl-bis(pyridylideneamide) ligands was synthesized in excellent yields, with the pyridylidene amide in meta or in para position (m-PYA and p-PYA, respectively). While complex [Ru(p-PYA)(MeCN)3]2+ is catalytically silent in transfer hydrogenation, its meta isomer [Ru(m-PYA)(MeCN)3]2+ shows considerable activity with turnover frequencies at 50% conversion TOF50 = 100 h-1. Spectroscopic, electrochemical, and crystallographic analyses suggest considerably stronger donor properties of the zwitterionic m-PYA ligand compared to the partially pi-acidic p-PYA analogue, imparted by valence isomerization. Further catalyst optimization was achieved by exchanging the ancillary MeCN ligands with imines (4-picoline), amines (ethylenediamine), and phosphines (PPh3, dppm, dppe). The most active catalyst was comprised of the m-PYA pincer ligand and PPh3, complex [Ru(m-PYA)(PPh3)(MeCN)2]2+, which reached a TOF50 of 430 h-1 under aerobic conditions and up to 4000 h-1 in the absence of oxygen. The presence of oxygen reversibly deactivates the catalytically active species, which compromises activity, but not longevity of the catalyst. Ligand exchange kinetic studies by NMR spectroscopy indicate that the strong trans effect of the phosphine is critical for high catalyst activity. Diaryl, aryl-alkyl, and dialkyl ketones were hydrogenated with high conversion, and alpha,beta-unsaturated ketones produced selectively the saturated ketone as the only product due to exclusive C=C bond hydrogenation, a distinctly different selectivity from most other transfer hydrogenation catalysts.
Note that a catalyst decreases the activation energy for both the forward and the reverse reactions and hence accelerates both the forward and the reverse reactions.COA of Formula: C17H14O, you can also check out more blogs about538-58-9
Reference£º
Synthesis and Crystal Structure of a Chiral?C3-Symmetric Oxygen Tripodal Ligand and Its Applications to Asymmetric Catalysis,
Chiral lanthanide(III) complexes of sulphur¨Cnitrogen¨Coxygen ligand derived from aminothiourea and sodium?D-camphor-¦Â-sulfonate