Effect of positive-charges in diphosphino-imidazolium salts on the structures of Ir-complexes and catalysis for hydroformylation
摘要:
The effect of positive charges in the diphosphino-imidazolium salts of L2 was investigated in terms of coordinating character, structures of corresponding Ir-complexes and catalysis for hydroformylation. It was found that the involved positive charges exhibited strong electron-withdrawing effect on the neighbored phosphine fragment, rendering L2 more pi-acceptor ability than the corresponding neutral counterpart of L1. Consequently, the changed coordinating ability of L1 and L2 led to the variety in the structures and components for the Ir-complexes (Ir-L1a, Ir-L1b, Ir-L2a, and Ir-L2b). The complexation of L2 with Ir(acac)(CO)(2) led to a novel five-coordinate Ir(II)-complex of Ir-L2a chelated by a PCC (phosphine-carboanion-carbene) pincer in tripodal mode, whereas the complexation of L1 with Ir(acac)(CO)(2) led to a four-coordinate square-planar KO-complex of Ir-L1a chelated by a PCP (phosphine-carboanion-phosphine) pincer. In addition, the different catalytic performances of these Ir-complexes ligated by L1 and L2 for hydroformylation of olefins were investigated. (C) 2015 Elsevier B.V. All rights reserved.
Co-catalysis of a bi-functional ligand containing phosphine and Lewis acidic phosphonium for hydroformylation–acetalization of olefins
作者:Yong-Qi Li、Peng Wang、Huan Liu、Yong Lu、Xiao-Li Zhao、Ye Liu
DOI:10.1039/c5gc02127h
日期:——
L2 containing a phosphine and a Lewis acidic phosphonium exhibited synergetic catalysis and sequential catalysis for one-pot hydroformylation–acetalization.
L2 包含一种膦和一种路易斯酸性磷酸铵,展示了协同催化和顺序催化,用于一锅法羰基化-缩醛化。
Direct Amination of Bio-Alcohols Using Ammonia
作者:Dennis Pingen、Olivier Diebolt、Dieter Vogt
DOI:10.1002/cctc.201300407
日期:2013.10
A slightly adapted catalyst system has been successfully applied in the directamination of primary and secondaryalcohols. Moreover, the applicability to diols has been shown, giving high selectivity towards the primary diamines. It was found that the Ru/P ratio as well as the amount of ammoniaused are highly important in this system, especially for higher substrate loadings. The catalyst was employed
Monosubstituted, Anionic Imidazolyl Ligands from N−H NHC Precursors and Their Activity in Pd‐Catalyzed Cross‐Coupling Reactions
作者:Erin E. Martinez、Christopher A. Jensen、Alexandra J. S. Larson、Karissa C. Kenney、Kyle J. Clark、S. Hadi Nazari、Gabriel A. Valdivia‐Berroeta、Stacey J. Smith、Daniel H. Ess、David J. Michaelis
DOI:10.1002/adsc.202000483
日期:2020.7.29
We report that treatment of several 2‐diphenylphosphinoimidazoles with Pd(II) salts generates monosubstituted N−H NHC−Pd complexes via insertion into the C−P bond. Removal of the N−H proton in situ leads to anionic (X‐type) or imidazolyl‐Pd complexes that are highly stable and catalytically active, achieving up to 340,000 turnovers at 1 ppm catalyst loading in Suzuki‐Miyaura reactions. DFT‐calculated
作者:M. N. Chevykalova、L. F. Manzhukova、N. V. Artemova、Yu. N. Luzikov、I. E. Nifant"ev、E. E. Nifant"ev
DOI:10.1023/a:1022483912466
日期:——
The influence of aryl, heterocyclic, amide. alkyl, alkoxyl, thioalkoxyl, and ferrocenyl substituents at the phosphorus atom on its electron-donating ability was studied by the measurement of direct P-31-Se-77 spin-spin coupling constants for the corresponding selenides. Series of diphenylorganylphosphines and their selenides were studied.
Synthesis, spectroscopic and structural characterization of novel adducts of some silver(I) salts with the ambidentate donor PPh2py
作者:Augusto Cingolani、Effendy、Domenico Martini、Claudio Pettinari、Brian W. Skelton、Allan H. White
DOI:10.1016/j.ica.2005.12.031
日期:2006.4
Syntheses, spectroscopic (R, H-1 and P-31 NMR) and some 'low'-temperature single-crystal X-ray structural characterizations are reported for a wide variety of adducts of AgX:PPh(2)py (:S) (n:m(:x)) (X = Cl, Br, I, NO2, SCN, ClO4, BF4, O2CCF3 (tfa), O2CCH3 (ac), O2CC3R7 (hefb), S2CN(C2H5)(2) (dtc), 1/2 SO42-; PPh(2)py = L = diphenyl-2-pyridylphosphine) stoichiometry. All compounds are binuclear, a wide range of (AgAg)-Ag-... distances being found, bridging entities being diverse, either anionic X or the P,N-ambidentate ligand PPh(2)py. PPh(2)py acts as a terminal P-donor in Agdtc: PPh(2)py (1:1)(2) and in [(Ph(2)py)(2)Ag([mu-Cl)(2)Ag(PPh(2)py)(NCMe)], but fully utilizes its coordinating capabilities in [(MeCN)Ag(mu-PPh(2)py)(3)Ag(OHI2)](ClO4)(2) and [(NO2)Ag(p-PPh(2)py)(2)Ag(O2N)]. Comparison is made between the latter compound and the analogous species [(NO2)Ag(mu-PPh(2)bim)(2)Ag(O2N)] (PPh(2)bim=L'=1-benzyl-2-imidazolyldiphenylphosphine). (c) 2005 Elsevier B.V. All rights reserved.