Pincer Complexes of Lithium, Sodium, Magnesium and Related Metals: A Discussion of Solution and Solid-State Aggregated Structure and Reactivity

2015 ◽  
pp. 17-44 ◽  
Author(s):  
Robert A. Gossage
Keyword(s):  
Solid State ◽  
Pincer Complexes ◽  
Sodium Magnesium

Reactions of a pincer proligand with copper iodide: bridging instead of C–H metalation

2020 ◽  
Vol 98 (9) ◽  
pp. 524-530
Author(s):  
Taghrid Chahrour ◽  
Annie Castonguay ◽  
Paul O. Oguadinma ◽  
Frank Schaper ◽  
Davit Zargarian
Keyword(s):  
Solid State ◽  
The Other ◽  
Strong Preference ◽  
Pincer Complexes ◽  
Divalent Copper ◽  
Copper Iodide ◽  
Tetrahedral Geometry ◽  
Central Carbon ◽  
Copper Center ◽  
Solid State Structures

Various precursors of divalent copper have been treated with the meta-disubstituted phenylene-based proligand POC(H)OP (1,3-(i-Pr2PO)2C6H4) with the objective of preparing classical pincer complexes (POCOP)CuX. However, in no case was such species obtained, presumably owing to the difficult C–H metallation step. Analogous reactions of monovalent precursors were also unsuccessful, whereas reaction of POC(H)OP with CuI under different conditions gave the non-metallated adducts {(μ, κP, [Formula: see text]-POC(H)OP)Cu(μ-Ι)}2, 1, {(μ, κP, [Formula: see text]-POC(H)OP)Cu2(μ-Ι)2(DMAP)2}, 2 (DMAP = 4-dimethylaminopyridine), and {(μ, κP, [Formula: see text]-POC(H)OP)Cu2(μ3-Ι)2}2, 3. Treating 1 with DMAP gave the adduct 2, whereas 3 could be obtained by treating 1 with BuLi or by sublimation of 1. The solid state structures of these complexes revealed the tetrahedral geometry that might be anticipated for the d10 Cu(I) centers, in addition to fairly close I–H distances; on the other hand, no C–H interaction (agostic or otherwise) was observed with the Cu centers in any of these structures. The unsuccessful metallation of the C(2)–H moiety is thought to be a result of the strong preference of monovalent copper center to form bridging interactions with iodide and the POC(H)OP ligand; this appears to prevent the approach of the central carbon of the ligand to the Cu centers.

Striking Differences between the Solution and Solid-State Reactivity of Iron PNP Pincer Complexes with Carbon Monoxide

2009 ◽  
Vol 28 (24) ◽  
pp. 6902-6914 ◽  
Author(s):  
David Benito-Garagorri ◽  
Luis Gonçalo Alves ◽  
Michael Puchberger ◽  
Kurt Mereiter ◽  
Luis F. Veiros ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Solid State ◽  
Pincer Complexes

Capturing Re(i) in an neutral N,N,N pincer Scaffold and resulting enhanced absorption of visible light

2016 ◽  
Vol 45 (21) ◽  
pp. 8885-8896 ◽  
Author(s):  
Philip Bulsink ◽  
Ahlam Al-Ghamdi ◽  
Prajesh Joshi ◽  
Ilia Korobkov ◽  
Tom Woo ◽  
...  
Keyword(s):  
Solid State ◽  
Visible Light ◽  
Thermal Transformation ◽  
Pincer Complexes ◽  
Enhanced Absorption

A family of Re(i) pincer complexes [κ3-2,6-{ArNCMe}2(NC5H3)]Re(CO)2X (ArC6H5, Me2C6H3, iPr2C6H3; X = Cl, Br) and (κ3-terpy)Re(CO)2X (X = Cl, Br) is accessed via an unconventional thermal transformation of bidentate complexes by heating in the solid state to 200–240 °C under nitrogen.

scholarly journals Late Transition Metal Complexes of Pentafluorophenylphosphino-Pincer Ligands

2021 ◽  
Author(s):  
◽  
Bradley George Anderson
Keyword(s):  
Catalytic Activity ◽  
Coordination Chemistry ◽  
Solid State ◽  
Nucleophilic Attack ◽  
Pincer Complexes ◽  
Pincer Ligands ◽  
Late Transition Metals ◽  
Suzuki Reactions ◽  
Pincer Complex ◽  
Late Transition

<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>

Reversible Reactions of Ni and Pd Hydroxo Pincer Complexes [(iPrPCP)M-OH] with CO2: Solid-State Study of the Decarboxylation of the Monomeric Bicarbonate Complexes [(iPrPCP)M-OCOOH] (M = Ni, Pd)

2013 ◽  
Vol 2013 (32) ◽  
pp. 5555-5566 ◽  
Author(s):  
Luis Miguel Martínez-Prieto ◽  
Concepción Real ◽  
Elena Ávila ◽  
Eleuterio Álvarez ◽  
Pilar Palma ◽  
...  
Keyword(s):  
Solid State ◽  
Pincer Complexes ◽  
State Study ◽  
Reversible Reactions

scholarly journals Na1.85Mg1.85In1.15(PO4)3 and Ag1.69Mg1.69In1.31(PO4)3 with alluaudite-type structures

2018 ◽  
Vol 74 (9) ◽  
pp. 1358-1361 ◽  
Author(s):  
Ahmed Ould Saleck ◽  
Abderrazzak Assani ◽  
Mohamed Saadi ◽  
Cyrille Mercier ◽  
Claudine Follet ◽  
...  
Keyword(s):  
Solid State ◽  
Single Crystals ◽  
Three Dimensional ◽  
Solid State Reactions ◽  
Monovalent Cations ◽  
Coordination Numbers ◽  
Sodium Magnesium ◽  
Coordination Spheres ◽  
Silver Magnesium ◽  
Cationic Disorder

Single crystals of two new phosphates, sodium magnesium indium(III) tris(orthophosphate) and silver magnesium indium(III) tris(orthophosphate), were obtained from solid-state reactions. The two phosphates are isotypic and exhibit alluaudite-type structures. They are characterized by a cationic disorder of the Mg and In sites and a partial occupation of the Na and Ag sites, respectively. The structure of both phosphates is made up of chains of edge-sharing [(Mg,In)O6] octahedra extending parallel to [10\overline{1}]. Adjacent chains are linked by PO4 tetrahedra to form a three-dimensional framework delimiting two types of channels parallel to [001] in which the monovalent cations are situated. The coordination numbers of the Na+ cations are 6 and 8, and for both Ag+ cations 6. The corresponding coordination spheres are considerably distorted.

scholarly journals Late Transition Metal Complexes of Pentafluorophenylphosphino-Pincer Ligands

2021 ◽  
Author(s):  
◽  
Bradley George Anderson
Keyword(s):  
Catalytic Activity ◽  
Coordination Chemistry ◽  
Solid State ◽  
Nucleophilic Attack ◽  
Pincer Complexes ◽  
Pincer Ligands ◽  
Late Transition Metals ◽  
Suzuki Reactions ◽  
Pincer Complex ◽  
Late Transition

<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>

Water-soluble NNN-pincer complexes of cobalt, nickel and palladium: Solid-state structures and catalytic activity

Polyhedron ◽  
2018 ◽  
Vol 143 ◽  
pp. 138-143 ◽  
Author(s):  
Joshua Heidebrecht ◽  
Chris Gendy ◽  
Benjamin S. Gelfand ◽  
Roland Roesler
Keyword(s):  
Catalytic Activity ◽  
Solid State ◽  
Water Soluble ◽  
Pincer Complexes ◽  
Cobalt Nickel ◽  
Solid State Structures

Preparation of Thin Cadmium Telluride Samples for Electron Microscope Studies

1974 ◽  
Vol 32 ◽  
pp. 548-549
Author(s):  
T. J. Magee ◽  
J. Peng ◽  
J. Bean
Keyword(s):  
Electron Microscope ◽  
Sulfuric Acid ◽  
Solid State ◽  
Sample Preparation ◽  
Cadmium Telluride ◽  
Potassium Dichromate ◽  
Optical Components ◽  
The Past ◽  
Solid State Devices

Cadmium telluride has become increasingly important in a number of technological applications, particularly in the area of laser-optical components and solid state devices, Microstructural characterizations of the material have in the past been somewhat limited because of the lack of suitable sample preparation and thinning techniques. Utilizing a modified jet thinning apparatus and a potassium dichromate-sulfuric acid thinning solution, a procedure has now been developed for obtaining thin contamination-free samples for TEM examination.

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