Synthesis and Catalytic Activity of Molybdenum-Nitride Complexes Bearing Pincer Ligands

2015 ◽  
Vol 2015 (10) ◽  
pp. 1789-1794 ◽  
Author(s):  
Eriko Kinoshita ◽  
Kazuya Arashiba ◽  
Shogo Kuriyama ◽  
Aya Eizawa ◽  
Kazunari Nakajima ◽  
...  
2014 ◽  
Vol 67 (10) ◽  
pp. 1387 ◽  
Author(s):  
Shi-Qiang Bai ◽  
Lu Jiang ◽  
Sheng-Li Huang ◽  
Ming Lin ◽  
Shuang-Yuan Zhang ◽  
...  

Composite Pd/Fe3O4 (1) was designed and synthesised by immobilization of tridentate pincer ligands with triethoxysilane groups on Fe3O4 nanoparticles, PdII complexation, and in-situ reduction process. The composite was characterised by transmission electron microscopy, scanning electron microscopy energy-dispersive X-ray spectroscopy, powder X-ray diffraction, vibrating sample magnetometer, Fourier transform infrared spectroscopy, thermogravimetric analysis, and Brunauer–Emmett–Teller analysis. The composite featured Pd nanoparticles of ~2–4 nm, exhibited good thermal stability and hydrophilic property as well as excellent catalytic activity towards the reduction of 4-nitrophenol to 4-aminophenol in water.


2017 ◽  
Vol 7 (8) ◽  
pp. 1671-1678 ◽  
Author(s):  
Xiaojuan Fu ◽  
Haiquan Su ◽  
Wenchao Yin ◽  
Yixiu Huang ◽  
Xiaojun Gu

The synergistic effect between Mo–Co in Co3Mo3N leads to its enhanced catalytic activity and stability in CO2 reforming of methane.


2012 ◽  
Vol 31 (23) ◽  
pp. 8437-8443 ◽  
Author(s):  
Eriko Kinoshita ◽  
Kazuya Arashiba ◽  
Shogo Kuriyama ◽  
Yoshihiro Miyake ◽  
Ryuji Shimazaki ◽  
...  

2016 ◽  
Vol 45 (36) ◽  
pp. 14335-14342 ◽  
Author(s):  
Ashwin G. Nair ◽  
Roy T. McBurney ◽  
D. Barney Walker ◽  
Michael J. Page ◽  
Mark R. D. Gatus ◽  
...  

A series of hemilabile NHC Ru(ii) complexes were synthesised and assessed for their catalytic activity for transfer hydrogenation reactions.


2021 ◽  
Author(s):  
◽  
Bradley George Anderson

<p>This thesis details the synthesis of new examples of electron-poor pincer ligands, featuring bis(pentafluorophenyl)phosphine donors attached to 1,3-substituted phenylene or 2,6-substituted pyridine backbones, to create tridentate PCP and PNP ligands. The effect of the ligands’ electronic nature on the coordination chemistry and ease of pincer complex synthesis with late transition metals is discussed, as is the catalytic activity of the resultant palladium pincer complexes in the Heck and Suzuki reactions. Symmetric PCP and PNP ligands possessing bis(pentafluorophenyl)phosphinite and bis(pentafluorophenyl)phosphoramine functionalities were synthesised by reaction of bis(pentafluorophenyl)phosphine bromide with resorcinol, 3-hydroxybenzyl-di- tert -butylphosphine, 2,6-diaminopyridine, or 2,6-dihydroxypyridine, affording 1,3- [(C6F5)2PO]2C6H4 (POCOPH, 1), 1-[(C6F5)2PO]-3-(tBu2PCH2)2C6H4 (POCCPH, 3), 2,6-[(C6F5)2PNH]2C6H3N (PNNNP, 10), and 2,6-[(C6F5)2PO]2C6H3N (PONOP, 11) respectively. The previously reported 1,3-[(C6F5)2PCH2]2C6H4 (PCCCPH, 2) was also synthesised, with the literature yield improved upon by the use of magnesium-anthracene to generate the required Grignard reagent. The coordination chemistry of the POCOPH ligand 1 with platinum(0) alkene and platinum(II) dimethyl precursors revealed an affinity for the formation of cis-bridged oligomeric structures. The dimer [(POCOPH)Pt(nb)]2 (14, nb = norbornene) was isolated and crystallographically characterised from the reaction between 1 and [Pt(nb)3]. The solid state structure revealed the presence of stabilising - interactions between the aromatic ligand backbones, which were also observed in solution by 1H NMR spectroscopy. Reactions of ligand 1 with platinum and palladium dichloride or chloromethyl starting materials led to rare examples of cis,trans-dimers of the type cis,trans-[(POCOPH)MClX]2 (M = Pd, Pt; X = Cl, Me). In part due to facile dimer formation with 1, metallation of the ligand backbone to form the tridentate pincer complex [(POCOP)PtCl] (25) required long reaction times and high temperatures. It was observed that platinum dichloride starting materials with more strongly binding ancillary ligands were less prone to oligomer formation, and could facilitate more rapid metallation to from 25. More facile pincer complex formation was also observed for more electron-rich ligands with both PCP and PNP pincer ligands. The electron poor platinum and palladium POCOP, PCCCP, and POCCP pincer complexes (where the free ligand had been deprotonated upon metallation) were synthesised and subsequently converted into the metal carbonyl species [(PCP)M(CO)]+. Analysis of C−O stretching frequencies by infrared spectroscopy confirmed complexes of POCOP ligand 1 were the most electron poor, while those of POCCP ligand 3 were the most electron rich. Decarbonylation of the palladium pincer complexes was observed in solution and in the solid state, and was more facile for complexes with a higher wavenumber C−O stretch. Reaction of the [(PCP)PtCl] pincer complexes with methyl nucleophiles revealed that treatment with methylmagnesium iodide resulted in halide exchange, while methyllithium promoted nucleophilic attack at phosphorus. Spectroscopic data indicated that in one instance this led to pentafluorophenyl migration to the metal centre to form a [(PCP)Pt(C6F5)] complex. Dimethylzinc was successful in methylating the platinum PCP complexes; however, it was observed to degrade the palladium PCP pincer complexes. Treatment of the rhodium PNP pincer complex [(PNNNP)RhCl] (49) with dimethylzinc also resulted in degradation, which spectroscopic evidence indicated proceeded via ligand deprotonation and the formation of a zinc adduct of 49. Low temperature protonolysis of the [(PCP)PtMe] species did not reveal any information about possible interactions between the metal and liberated methane. The catalytic activity of the electron-poor [(PCP)PdCl] complexes were assessed in the Heck and Suzuki cross-coupling reactions. The complexes of 1, 2, and 3 were all found to possess only modest activity in the Heck reaction, functioning as precatalysts which decomposed to give catalytically-active Pd(0) colloids. Under milder Suzuki reaction conditions, the most electron-poor complex, [(POCOP)PdCl] (28) proved to be one of the most active pincer catalysts known for this reaction, able to achieve a turnover number of 176,000 for the coupling of electronically-deactivated aryl bromides and phenylboronic acid. Mercury poisoning tests revealed that Suzuki reactions catalysed by 28 proceeded via a homogeneous active species.</p>


2017 ◽  
Vol 845 ◽  
pp. 63-70 ◽  
Author(s):  
Ashwin G. Nair ◽  
Roy T. McBurney ◽  
Mark R.D. Gatus ◽  
D.Barney Walker ◽  
Mohan Bhadbhade ◽  
...  

2019 ◽  
Vol 48 (43) ◽  
pp. 16322-16329 ◽  
Author(s):  
Sandeep Kaur-Ghumaan ◽  
Patrick Hasche ◽  
Anke Spannenberg ◽  
Torsten Beweries

The catalytic activity of a series of nickel complexes with different phosphinite/thiophosphinite ligands for electrocatalytic proton reduction strongly depends on the nature of the pincer ligands.


2019 ◽  
Vol 48 (47) ◽  
pp. 17633-17643 ◽  
Author(s):  
Yazhou Ding ◽  
Qiang-Qiang Ma ◽  
Jiaxin Kang ◽  
Jie Zhang ◽  
Shujun Li ◽  
...  

The structure, properties and catalytic activity of two series of Pd(ii) complexes supported by PBP and POCOP pincer ligands were investigated.


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