- A One-Step Preparation of Tetradentate Ligands with Nitrogen and Phosphorus Donors by Reductive Amination and Representative Iron Complexes
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The synthesis and use of the first examples of unsymmetrical, mixed phosphine donor tripodal NPP2′ ligands N(CH2CH2PR2)2(CH2CH2PPh2) are presented. The ligands are synthesized via a convenient, one pot reductive amination using 2-(diphenylphosphino)ethylamine and various substituted phosphonium dimers in order to introduce mixed phosphine donors substituted with P/P′, those being Ph/Cy (2), Ph/iPr (3), Ph/iBu (4), Ph/o-Tol (5), and Ph/p-Tol (6). Additionally, we have developed the first known synthesis of a symmetrical tripodal NP3 ligand N(CH2CH2PiBu2)3 using bench safe ammonium acetate as the lone nitrogen source (7). This new protocol eliminates the use of extremely dangerous nitrogen mustard reagents typically required to synthesize NP3 ligands. Some of these tetradentate ligands and also P2NN′ ligands N(CH2-o-C5H4N)(CH2CH2PR2)2 (P2NN′-Cy, R = Cy; P2NN′-Ph, R = Ph) prepared by reductive amination using 2-picolylamine are used in the synthesis and reactions of iron complexes. FeCl2(P2NN′-Cy) (8) undergoes single halide abstraction with NaBPh4 to give the trigonal bipyramidal complex [FeCl(P2NN′-Cy)][BPh4] (9). Upon exposure to CO(g), complex 9 readily coordinates CO giving [FeCl(P2NN′-Cy)(CO)][BPh4] (10), and further treatment with an excess of NaBH4 results in formation of the hydride complex [Fe(H)(P2NN′-Cy)(CO)][BPh4] (11). Our previously reported complex FeCl2(P2NN′-Ph) undergoes double halide abstraction with NaBPh4 in the presence of the coordinating solvent to give [Fe(NCMe)2(P2NN′-Ph)][BPh4]2 (12). Ligand 3 can be coordinated to FeCl2, and upon sequential halide abstraction, treatment with NaBH4, and exposure to an atmosphere of dinitrogen, the dinitrogen hydride complex [Fe(H)(NPP2′-iPr)(N2)][BPh4] (13) is isolated. Our symmetrical NP3 ligand 7 can also be coordinated to FeCl2 and, upon exposure to an atmosphere of CO(g), selectively forms [FeCl(NP3)(CO)][BPh4] (14) after salt metathesis with NaBPh4. Complex 14 can be treated with an excess of NaBH4 to give the hydride complex [Fe(H)(NP3)(CO)][BPh4] (15), which can further be deprotonated/reduced to the Fe(0) complex Fe(NP3)(CO) (16) upon treatment with an excess of KH.
- Gradiski, Matthew V.,Kharat, Ali Nemati,Lough, Alan J.,Morris, Robert H.,Ong, Maegan S. E.,Smith, Samantha A. M.
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Read Online
- Method for conducting catalytic hydrogenation on nitrogen-containing unsaturated heterocyclic compound
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The invention provides a method for conducting catalytic hydrogenation on a nitrogen-containing unsaturated heterocyclic compound, and belongs to the technical field of catalytic hydrogenation. The provided method for conducting catalytic hydrogenation on the nitrogen-containing unsaturated heterocyclic compound comprises the following step: in the presence of hydrogen and a manganese catalyst, with the nitrogen-containing unsaturated heterocyclic compound as a substrate, carrying out a hydrogenation reaction. According to the method for conducting catalytic hydrogenation on the nitrogen-containing unsaturated heterocyclic compound, he adopted manganese catalyst is an NNP-type pincer manganese catalyst, has the advantages of being cheap, easy to obtain and low in toxicity compared with noble metal catalysts, has the advantages of being wide in substrate applicability and high in target product yield compared with an existing cheap metal iron catalyst or cobalt catalyst, and is higher in electron donating ability and smaller in steric hindrance compared with a PNP-type pincer manganese catalyst, and thus shows higher reaction activity in a series of hydrogenation reactions, and thetarget product yield is up to 99%.
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Paragraph 0071; 0077-0079
(2020/01/03)
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- β-Amino Phosphine Mn Catalysts for 1,4-Transfer Hydrogenation of Chalcones and Allylic Alcohol Isomerization
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Mn complexes with amino acid derived PN ligands were used in the catalytic transfer hydrogenation (TH) of ketone and chalcone substrates in 2-propanol with mild heating. Moreover, chalcones are reduced selectively to the saturated ketone at short times and can be fully converted to the alcohol when reactions are prolonged. The mechanism of chalcone reduction was briefly considered. Allylic alcohols are not reactive in 2-propanol, but quantitative isomerization occurs in toluene. Thus, we suspect that the allylic alcohols are dehydrogenated and the resulting ketone is formed through a direct 1,4-hydrogenation of the chalcone. Finally, several other related ligands that have been used in Mn-based TH reactions were explored to test the viability of ligand design in favoring chemoselectivity. The β-amino phosphine ligands proved most effective in this regard.
- Vigneswaran, Vipulan,MacMillan, Samantha N.,Lacy, David C.
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p. 4387 - 4391
(2019/11/14)
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- A Ruthenium Catalyst with Unprecedented Effectiveness for the Coupling Cyclization of - Amino Alcohols and Secondary Alcohols
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The ruthenium complex (8-(2-diphenylphosphinoethyl)aminotrihydroquinolinyl)(carbonyl)(hydrido)ruthenium chloride exhibited extremely high efficiency toward the coupling cyclization of -amino alcohols with secondary alcohols. The corresponding products, pyridine or quinoline derivatives, are obtained in good to high isolated yields. On comparison with literature catalysts whose noble-metal loading with respect to -amino alcohols reached 0.5-1.0 mol % for Ru and a record lowest of 0.04 mol % for Ir, the current catalyst achieves the same efficiency with a loading of 0.025 mol % for Ru. The mechanism of acceptorless dehydrogenative condensation (ADC) was proposed on the basis of DFT calculations; in addition, the reactive intermediates were determined by GC-MS, NMR, and single-crystal X-ray diffraction. The catalytic process is potentially suitable for industrial applications.
- Pan, Bing,Liu, Bo,Yue, Erlin,Liu, Qingbin,Yang, Xinzheng,Wang, Zheng,Sun, Wen-Hua
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p. 1247 - 1253
(2016/02/18)
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- Photosensitive iron(II)-based CO-releasing molecules (CORMs) with vicinal amino and diphenylphosphino substituted chelating ligands
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The reactions of [Fe(H2O)6] [BF4] 2 with aminoethyl-diphenylphosphane and 2-(diphenylphosphino)aniline lead to the formation of trans-[Fe(NC-Me)2(H2NCH 2CH2PPh2)2] [BF4] 2 (1a) and trans-[Fe(NC-Me)2(H2NC 6H4-2-PPh2)2] [BF4] 2 (1b), respectively. One acetonitrile ligand can be substituted by CO yielding [Fe(CO)(NC-Me)(H2NCH2CH2PPh 2)2] [BF4]2 (2a, CORM-P1) and [Fe(CO)(NC-Me)(H2NC6H4-2-PPh2) 2] [BF4]2 (2b, CORM-P2). Upon irradiation with visible light, CO is liberated making especially 2a a promising photo-CORM whereas for 2b a slow and incomplete CO release is observed.
- Jazzazi, Taghreed M.A.,G?rls, Helmar,Gessner, Guido,Heinemann, Stefan H.,Westerhausen
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- HYDROGENATION AND DEHYDROGENATION CATALYST, AND METHODS OF MAKING AND USING THE SAME
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The present application discloses complexes useful as catalysts for organic chemical synthesis including hydrogenation and dehydrogenation of unsaturated compounds or dehydrogenation of substrates. The range of hydrogenation substrate compounds includes esters, lactones, oils and fats, resulting in alcohols, diols, and triols as reaction products. The catalysts of current application can be used to catalyze a hydrogenation reaction under solvent free conditions. The present catalysts also allow the hydrogenation to proceed without added base, and it can be used in place of the conventional reduction methods employing hydrides of the main-group elements. Furthermore, the catalysts of the present application can catalyze a dehydrogenation reaction under homogenous and/or acceptorless conditions. As such, the catalysts provided herein can be useful in substantially reducing cost and improving the environmental profile of manufacturing processes for variety of chemicals.
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Paragraph 0088; 0089
(2013/03/26)
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- Aminophosphine ligands R2P(CH2)nNH 2 and ruthenium hydrogenation catalysts RuCl2(R 2P(CH2)nNH2)2
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The aminophosphine ligands R2P(CH2) 2NH2 and R2P(CH2)3NH 2 (R = Ph, iPr, tBu) were isolated in good to excellent yields from the reaction of LiPR2 with Cl(CH 2)2N(TMS)2 and Cl(CH2) 3N(TMS)2, respectively, followed by hydrolysis. This approach allows fine tuning of the ligands' stereoelectronic properties through the variation of the substituents on the phosphine. The aminophosphine ligands were used to prepare the ruthenium complexes RuCl2(R 2P(CH2)2NH2)2 and RuCl2(R2P(CH2)3NH2) 2 by reacting a 2:1 mixture of the respective ligand and [RuCl 2(cod)]n in an appropriate solvent. The resulting complexes were found to be excellent catalysts for the hydrogenation of ketones and imines. The Royal Society of Chemistry 2009.
- Jia, Wenli,Chen, Xuanhua,Guo, Rongwei,Sui-Seng, Christine,Amoroso, Dino,Lough, Alan J.,Abdur-Rashid, Kamaluddin
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experimental part
p. 8301 - 8307
(2010/03/04)
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- METHOD FOR THE PREPARATION OF AMINOPHOSPHINE LIGANDS AND THEIR USE IN METAL CATALYSTS
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The present application is directed to i) a two-step method for synthesizing phosphme-ammophosphme (P,N,P) ligands, ii) the use of such ligands in the preparation of metal complexes as hydrogenation catalysts, and iii) ammophosphme (P,N) and phosphme-ammo
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Page/Page column 33-34
(2009/01/24)
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- A mild and efficient CsOH-promoted synthesis of ditertiary phosphines
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A mild and efficient method for the synthesis of ditertiary phosphines has been developed. In the presence of cesium hydroxide, molecular sieves, and DMF, various dihalides were coupled with diphenylphosphine at room temperature, and the results have demonstrated that this methodology offers a general synthetic procedure producing a variety of ditertiary phosphines in high yields.
- Honaker, Matthew T.,Salvatore, Ralph Nicholas
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p. 277 - 283
(2007/10/03)
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- CsOH-promoted P-alkylation: A convenient and highly efficient synthesis of tertiary phosphines
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A mild and efficient method for the synthesis of tertiary phosphines and ditertiary phosphines has been developed. In the presence of cesium hydroxide, molecular sieves and DMF at room temperature, various secondary phosphines and alkyl bromides were examined, and the results have demonstrated that this methodology offers a general synthetic procedure to produce tertiary phosphines in moderate to high yields. Optically active tertiary phosphine synthesis is also described.
- Honaker, Matthew T.,Sandefur, Benjamin J.,Hargett, James L.,McDaniel, Alicia L.,Salvatore, Ralph Nicholas
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p. 8373 - 7377
(2007/10/03)
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- Control of aminophosphine chelate ring-opening in Pt(II) and Pd(II) complexes: Potential dual-mode anticancer agents
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We show that bis(aminophosphine) complexes of the type [M(R1R2N(CH2)nPPh2)2 ]2+, M = Pt(II) or Pd(II), can exist in chelate ring-closed and ring-opened forms both in the solid state and in aqueous solution. The equilibrium between them in solution can be controlled by the nature of the groups R1 and R2 (H, Me, Bz, cyclohexyl), by the bridge length n, and by the pH and Cl- concentration. X-Ray crystal structures are reported for the ring-closed complexes cis-[Pt(H2N(CH2)2PPh2-P,N)2 ]Cl2, cis-[Pt(H2N(CH2)3PPh2-P,N)2 ]Cl2, and cis-[Pt(Me(H)N(CH2)2PPh2-P,N)2][HCl 2]2, the mono-ring-opened complex cis-[Pd(Me2N(CH2)2PPh2-N,P)Cl(Me 2NH(CH2)2PPh2-P)](NO3) 2, the di-ring-opened complex cis-[Pt(Me2N(CH2)3PPh2-P)2 CL2], and, for comparison, the monochelate cis-[Pd(Me2N(CH2)3PPh2-N,P)CL2 ]. These square-planar complexes exhibit varying degrees of distortion and variable M-N bond lengths dependent not only on the trans influence of P but also on steric effects within the complex, pH-induced chelate ring-opening of cis-[Pt(Me2N(CH2)2PPh2-P,N)2 ]CL2 had an associated pK value of 6.9. In contrast, complexes with R1 and R2 = H, n = 2 or 3 or R1 = H and R2 = Me, n = 2, are more difficult to ring-open. Thus the complexes cis-[Pt(Me(H)N(CH2)2-PPh2-P,N)2]CL 2 and cis-[Pt(H2N(CH2)3PPh2-P,N)2 ]CL2, had associated pK values of 2.1 and 2.9, respectively. These aminophosphine complexes may exhibit anticancer activity by two mechanisms: by disrupting mitochondrial membrane potentials as bis-chelated (ring-closed) lipophilic cations, or by direct binding to DNA bases as ring-opened complexes.
- Habtemanam, Abraha,Watchman, Beth,Potter, Brian S.,Palmer, Rex,Parsons, Simon,Parkin, Andrew,Sadler, Peter J.
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p. 1306 - 1318
(2007/10/03)
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- Absorption, Circular Dichroism, and Nuclear Magnetic Resonance Studies of Bis(acetylacetonato)cobalt(III) Complexes Containing 2-Aminoalkylphosphine Chelates with Phosphorus and Nitrogen Donor Atoms
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Bis(acetylacetonato)cobalt(III) complexes containing a variety of 2-aminoalkylphosphines, NH2CH2CH2P(C6H5)2, (CH3)2NCH2CH2P(C6H5)2, (S)-NH2CH(CH3)CH2P(C6H5)2, rac-NH2CH2CH2P(CH3)(C6H5), (R)-NH2CH2CH2P(C4H9)(C6H5) and NH2CH2CH2P(CH3)2, and a diphosphine, (C6H5)2PCH2CH2P(C6H5)2 were prepared and resolved (or separated) into optical isomers by SP-Sephadex column chromatography.Absorption, circular dichroism, and 1H and 13C NMR spectra of the new complexes were measured and the results compared with those of the related complexes.Positions of the 2-aminoalkylphosphine and the related ligands in the spectrochemical series were as follows; CN- > NH2CH2CH2P(CH3)2 > (C6H5)2PCH2CH2P(C6H5)2 > NH2CH2CH2P(CH3)(C6H5) NH2CH2CH2P(C4H9)(C6H5) > NH2CH(CH3)CH2P(C6H5)2 NH2CH2CH2P(C6H5)2 NH2CH2CH2NH2 > (CH3)2NCH2CH2P(C6H5)2.For the 13C NMR spectra, all the signals including those due to two diastereotopic phenyl groups on a phosphorus atom were assigned, and the chemical shifts and the coupling constants were determined.The methyl and carbonyl carbons which are trans to a phosphorus atom give a doublet signal due to four-bond (4J(C,P) = 6-7 Hz) and three-bond 3J(C,P) = 2-3 Hz) couplings, respectively, through a cobalt(III) ion.
- Kashiwabara, Kazuo,Kinoshita, Isamu,Ito, Tasuku,Fujita, Junnosuke
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p. 725 - 732
(2007/10/02)
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