120121-01-9Relevant academic research and scientific papers
A homochiral microporous hydrogen-bonded organic framework for highly enantioselective separation of secondary alcohols
Li, Peng,He, Yabing,Guang, Jie,Weng, Linghong,Zhao, John Cong-Gui,Xiang, Shengchang,Chen, Banglin
, p. 547 - 549 (2014)
A homochiral microporous hydrogen-bonded organic framework (HOF-2) based on a BINOL derivative has been synthesized and structurally characterized to be a uninodal 6-connected {3355667} network. This new HOF exhibits not only a permanent porosity with the BET of 237.6 m 2 g-1 but also, more importantly, a highly enantioselective separation of chiral secondary alcohols with ee value up to 92% for 1-phenylethanol.
Construction of pincer-type symmetrical ruthenium(II) complexes bearing pyridyl-2,6-pyrazolyl arms: Catalytic behavior in transfer hydrogenation of ketones
Zhu, Zhu,Zhang, Jie,Fu, Haiyan,Yuan, Maolin,Zheng, Xueli,Chen, Hua,Li, Ruixiang
, p. 52734 - 52739 (2014)
Convenient synthesis of four new distorted octahedral ruthenium(II) complexes (1, 2, 3, 4) having general molecular formula [RuCl2LPAr3] (L = pyridine-based tridentate ligands not containing N-H bonds) is described. Their composition and structure were determined by elemental analysis and NMR spectra, and complexes 2 and 4 were also identified by X-ray single-crystal diffraction. All ruthenium(II) complexes exhibited good to excellent catalytic activity in the transfer hydrogenation of ketones. Among them, complex 4 achieved the highest final TOF value of 51600 h-1 for a high molar ratio of substrate to catalyst (2000:1).
Iron(II) complexes for the efficient catalytic asymmetric transfer hydrogenation of ketones
Meyer, Nils,Lough, Alan J.,Morris, Robert H.
, p. 5605 - 5610 (2009)
Iron(II) carbonyl compounds of the type trans-[Fe(NCMe)(CO)(P-N-N-P)] [BF4]2 bearing the ethylenediamine-derived diiminodiphosphine ligands (R,R)- or (5,5)-1,2-diphenyl-1,2-diaminoethane were synthesized and characterized, including by their crystal structures. The new complexes are suitable precatalysts for the transfer hydrogenation of ketones at room temperature, giving turnover frequencies of up to 2600 h-1 with low catalyst loadings (0.025-0.17%). Screening experiments showed that the precatalysts are able to produce alcohols from a wide range of simple ketones. For sterically demanding prochiral ketones, excellent enantioselectivities were obtained (up to 96% ee).
Ruthenium(II) Complexes of 4′-(Aryl)-2,2′:6′,2′′-terpyridyl Ligands as Simple Catalysts for the Transfer Hydrogenation of Ketones
Maity, Apurba,Sil, Amit,Patra, Sanjib K.
, p. 4063 - 4073 (2018)
A series of cationic [Ru(L)(PPh3)2Cl]+ (1–3) and neutral [Ru(L)(PPh3)Cl2] (4–6) RuII complexes were synthesized by reacting [RuCl2(PPh3)2] with 4′-(aryl)-2,2′:6′,2′′-terpyridyl-based ligands (L1–L3) with various aryl groups (tolyl, phenyl and 4-fluorophenyl). The synthesized RuII complexes were unambiguously characterized by various spectroscopic techniques such as FTIR and multinuclear NMR spectroscopy as well as HRMS. The neutral complexes (4–6) were also structurally characterized by single-crystal X-ray diffraction studies. Photophysical and electrochemical studies of the RuII complexes were performed to elucidate the effects of the 4′-aryl substituents of L1–L3. These RuII complexes show good catalytic activities in the transfer hydrogenation (TH) of ketones with a wide substrates scope in 2-propanol under reflux. An optimization study revealed that the neutral RuII complexes are better catalysts than the cationic RuII complexes for TH reactions. Finally, [Ru(L1)(PPh3)2H]+ (7) with a [RuII–H] functionality was successfully synthesized and isolated and is proposed as the catalytically active species. A control experiment with the [RuII–H] complex in the absence of base was performed to establish the mechanism for the catalytic TH of ketones.
Novel chiral tetraaza ligands: synthesis and application in asymmetric transfer hydrogenation of ketones
Shen, Wei-Yi,Zhang, Hui,Zhang, Hua-Lin,Gao, Jing-Xing
, p. 729 - 733 (2007)
Novel chiral tetraaza ligands, N1,N2-bis(2-(piperidin-1-yl)benzylidene)cyclohexane-1,2-diamine 1 and N1,N2-bis(2-(piperidin-1-yl)benzyl)cyclohexane-1,2-diamine 2, have been synthesized and fully characterized by
Room-temperature Ru(II)-catalyzed transfer hydrogenation of ketones and aldehydes in air
Zhao, Miao,Yu, Zhengkun,Yan, Shenggang,Li, Yang
, p. 4624 - 4628 (2009)
Transfer hydrogenation (TH) of ketones and aldehydes was efficiently carried out in 2-propanol at room temperature by means of a ruthenium(II) complex catalyst bearing a 2-(benzoimidazol-2-yl)-6-(pyrazol-1-yl)pyridine ligand. TH of the ketone substrates proceeded in air, reaching final TOFs of up to 59,400 h-1, and the reduction of aldehydes proceeded under a nitrogen atmosphere to achieve final TOFs of up to 5940 h-1.
Dimeric Ruthenium(II)-NNN Complex Catalysts Bearing a Pyrazolyl-Pyridylamino-Pyridine Ligand for Transfer Hydrogenation of Ketones and Acceptorless Dehydrogenation of Alcohols
Wang, Qingfu,Chai, Huining,Yu, Zhengkun
, p. 3638 - 3644 (2017)
Dimeric pincer-type ruthenium(II)-NNN complexes bearing an unsymmetrical pyrazolyl-pyridylamino-pyridine ligand were prepared and characterized by NMR, elemental analysis, and X-ray single crystal structural determination. These complexes exhibited very high catalytic activity for both transfer hydrogenation of ketones and acceptorless dehydrogenation of secondary alcohols, achieving TOF values up to 1.9 × 106 h-1 in the transfer hydrogenation of ketones. The high catalytic activity of the Ru(II) complex catalysts is attributed to the presence of the unprotected NH functionality in the ligand and hemilabile unsymmetrical coordination environment around the central metal atoms in the complex.
Assembled Multinuclear Ruthenium(II)-NNNN Complexes: Synthesis, Catalytic Properties, and DFT Calculations
Liu, Tingting,Wu, Kaikai,Wang, Liandi,Fan, Hongjun,Zhou, Yong-Gui,Yu, Zhengkun
, p. 93 - 104 (2020)
Using a coordinatively unsaturated 16-electron mononuclear ruthenium(II)-pyrazolyl-imidazolyl-pyridine complex [Ru(II)-NNN] as the building block and oligopyridines as the polydentate ligands, pincer-type tri- A nd hexanuclear ruthenium(II) complexes [Ru(II)-NNNN]n were efficiently assembled. These complexes were characterized by elemental analyses, NMR, IR, and MALDI-TOF mass spectroscopies. In refluxing 2-propanol, the multinuclear ruthenium(II)-NNNN complexes exhibited exceptionally high catalytic activity for the transfer hydrogenation of ketones at very low concentrations and reached turnover frequencies (TOFs) up to 7.1 × 106 h-1, featuring a remarkable cooperative effect from the multiple Ru(II)-NNNN functionalities. DFT calculations have revealed the origin of the high catalytic activities of these Ru(II)-NNNN complexes.
A family of novel cationic ruthenium pincer complexes: Synthesis, characterization and catalytic activity in the transfer hydrogenation of ketones
Wang, Lei,Pan, Hai-Ran,Yang, Qin,Fu, Hai-Yan,Chen, Hua,Li, Rui-Xiang
, p. 1422 - 1427 (2011)
A family of novel cationic ruthenium complexes [RuHL(PAr3) 2]Cl (Ar = phenyl, p-methoxyphenyl, and p-trifluoromethylphenyl; L = 2,6-bis(1,5-diphenyl-1H-pyrazol-3-yl)pyridine) has been synthesized and characterized by IR, 31P{1H} NMR, 1H NMR and elemental analyses. The [RuHL(PPh3)2]Cl was further identified by X-ray crystallography. These complexes exhibit good to excellent catalytic activities for the transfer hydrogenation of ketones in refluxing 2-propanol, and the highest TOF is up to 3534 h- 1. The effect of electronic factors of these complexes on the transfer hydrogenation of ketones reveals that the catalytic activity is promoted by the electron-withdrawing phosphine.
Aza-crown compounds synthesised by the self-condensation of 2-amino-benzyl alcohol over a pincer ruthenium catalyst and applied in the transfer hydrogenation of ketones
Zhang, Shanshan,Wang, Zheng,Cao, Qianrong,Yue, Erlin,Liu, Qingbin,Ma, Yanping,Liang, Tongling,Sun, Wen-Hua
, p. 15821 - 15827 (2020)
A well-defined PNN-Ru catalyst was revisited to self-condense 2-aminobenzyl alcohol in forming a series of novel aza-crown compounds [aza-12-crown-3 (1), aza-16-crown-4 (2) and aza-20-crown-5 (3)]. All aza-crown compounds are separated and determined by NMR, IR, and ESI-MS spectroscopy as well as X-ray crystallography, indicating the saddle structure of 1 and the twisted 1,3-alternate conformation structure of 3. These aza-crown compounds have been explored to study ferric initiation of transfer hydrogenation (TH) of ketones into their corresponding secondary alcohols in the presence of 2-propanol with a basic t-BuOK solution, achieving a high conversion (up to 95%) by a ferric complex with 2 in a low loading (0.05 mol%). This journal is
