Studies on the magnetic cross-over in five-co-ordinate complexes of iron(II), cobalt(II), and nickel(II). Part II

Dahlhoff, W. V.; Nelson, S. M.

doi:10.1039/j19710002184

Cited by 108 publications

(90 citation statements)

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“…Pentane and diethyl ether were distilled with sodium and benzophenone, and dichloromethane with calcium hydride under nitrogen immediately before use. Bis[(η 3 -allyl)chloropalladium], [28] bis[(η 3 -1-methylallyl)chloropalladium], [28] bis[(η 3 -1,1-dimethylallyl)chloropalladium], [28] and 2,6-bis(diphenylphosphanylmethyl)pyridine [25] were prepared as described in the literature. 2,2Ј:6Ј,2"-terpyridine was purchased from Aldrich and used as received.…”

Section: Methodsmentioning

confidence: 99%

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η1- and η3-Allylpalladium(II) Complexes Bearing Potentially Tridentate Ligands: Synthesis, Solution Dynamics, and Crystal Structures

Barloy

Ramdeehul

Osborn

et al. 2000

Eur. J. Inorg. Chem.

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The potentially tridentate ligands 2,2′:6′,2"‐terpyridine (terpy) and 2,6‐bis(diphenylphosphanylmethyl)pyridine (PNP) have been used to prepare novel palladium−allyl complexes of general formula [(terpy)Pd(CH2CHCRR′)](BF4) [R = R′ = H (1); R = H, R′ = Me (2); R = R′ = Me (3)] and [(PNP)Pd(CH2CHCRR′)](BF4) [R = R′ = H (4); R = H, R′ = Me (5); R = R′ = Me (6)], which were characterized by elemental analysis, IR spectroscopy, and 13C, 31P and variable‐temperature 1H NMR spectroscopy. The low‐temperature 1H NMR spectra show that the configuration of the complexes in solution depends strongly on the nature of the ligand. The terpy complexes 1−3 are η3‐allyl species, where terpy is dihapto and one pyridine ring remains uncoordinated, whereas the PNP complexes 4−6 occur as η1‐allyl compounds with a trihapto PNP ligand. All complexes are fluxional through η3‐η1 exchange processes. Energy barriers of 47.5−48.6 kJ·mol−1 (243−262 K) are reported for the interconversion of terminal allylic protons (complexes 2−4). ΔG‡ is higher (71.1 kJ·mol−1 at 350 K) for the interconversion of the methyl groups in complex 6. A lower‐barrier oscillatory mechanism involving terpy (ΔG‡ = 43.9 kJ·mol−1 at 231 K) is also involved in complex 1. The X‐ray structures of complexes [(η3‐terpy)Pd(η1‐C5H9)](BF4) (3a) and [(η3‐PNP)Pd(η1‐C4H7)](BF4) (5a) are reported; the structure of 3a corresponds to a species that is not observed in solution.

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Section: Methodsmentioning

confidence: 99%

“…In addition, two bands are observed at 1599 and 1565 cm Ϫ1 in the spectra of complexes 4Ϫ6; this confirms that the nitrogen atom of PNP actually coordinates with the palladium atom in the solid state. [25] …”

Section: Solid-state Analysismentioning

confidence: 99%

η1- and η3-Allylpalladium(II) Complexes Bearing Potentially Tridentate Ligands: Synthesis, Solution Dynamics, and Crystal Structures

Barloy

Ramdeehul

Osborn

et al. 2000

Eur. J. Inorg. Chem.

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“…[29] Addition of a secondary phosphine to 2,6-bis(chloromethyl)pyridine followed by selective deprotonation using triethylamine was described specifically for the tert-butyl analogue 12…”

Section: Phmentioning

confidence: 99%

“…[29,30] One special feature of these 2,6-lutidinederived systems is their ease of deprotonation of the methylene spacer group, which effectively renders this ligand class "non-innocent". [31] The aim of this Minireview is to give a tantalizing overview of the interesting and useful chemistry available with this type of ligands, with a particular emphasis on the non-innocent (cooperative) ligand reactivity and (potential) applications in catalysis.…”

Section: Introductionmentioning

confidence: 99%

Neutral Tridentate PNP Ligands and Their Hybrid Analogues: Versatile Non‐Innocent Scaffolds for Homogeneous Catalysis

Vlugt¹,

Reek²

2009

Angew Chem Int Ed

414

145

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Ligands in coordination chemistry and homogeneous catalysis are traditionally "static" spectators that do not actively participate in the catalytic cycle. However, such classic systems do not provide additional "handles" that could facilitate or trigger alternative productive reaction pathways. Recent advances in the use of novel nitrogen-centered pincer systems have unveiled interesting opportunities for cooperative catalysis. The chemistry of pyridine-derived, neutral ligands is discussed, with a specific focus on their non-innocent behavior and potential as facilitators for metal-mediated organic transformations. This overview should provide inspiration and an incentive to incorporate non-innocent ligands and their metal complexes within old and new homogeneously catalyzed reactions.

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“…Two bands at 1615 and 1560 cm -1 are observed, the former being at higher energy than in the free ligand. [18] (11), PMePh 2 (12)] were prepared from 5 by the same procedure. On the contrary, attempts to abstract the chloride with AgBF 4 did not provide satisfactory results.…”

Section: Resultsmentioning

confidence: 99%

Synthesis and Structural Characterization of Pincer Pyridine Diphosphite Complexes of Rhodium and Iridium

et al. 2011

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The synthesis of a novel pyridine diphosphite ligand 1 has been described. From this ligand, rhodium– and iridium–chlorido complexes of formula [MCl(1)] (M = Rh, Ir) have been prepared. Chloride abstraction by treatment with NaBPh4 and a phosphane produced the corresponding cationic phosphane derivatives [M(1)L][BPh4] [L = PPh3 (Rh, Ir), PPh2Me (Ir)]. The analogous reaction of [RhCl(1)] with CNXy (Xy = 2,6‐Me2‐C6H3) and NaBPh4 yielded the monosubstituted complex [Rh(1)(CNXy)][BPh4], whereas the reaction between [IrCl(1)] and isonitriles led to the disubstituted complexes [Ir(1)(L)2][BPh4] (L = CNBn, CNCy). Ethylene compound [Rh(1)(C2H4)][BPh4] was obtained from the reaction of [RhCl(1)] with NaBPh4 under ethylene, whereas [Ir(1)(C2H4)][BPh4] was synthesized by a treatment of [{IrCl(COE)2}2] with ethylene followed by addition of 1 and NaBPh4. An IR analysis of the isocyanide complexes indicates a very poor π‐donor ability of the [M(1)]+ fragment, therefore the isocyanide metal bond is mostly due to σ donation from the isocyanide. Characterization by X‐ray crystallography of [Rh(1)(PPh3)][BPh4], [Rh(1)(MeCN)][BPh4] and [Ir(1)(PPh2Me)][BPh4] displays a square‐planar structure with ligand 1 coordinated in a pincer fashion for these complexes. In addition, the ethylene derivative [Rh(1)(C2H4)][BPh4] shows a near in‐plane conformation of the ethylene ligand, with a short C–C distance (1.319 Å). Moreover, in all the structures, the diphosphite ligand exhibits a meso conformation irrespective of the size of the neutral ancillary ligand. An examination of the behaviour of some of these complexes in catalytic hydrogenation has shown that [IrCl(1)] is an active catalyst in the reduction of 2‐methylquinoline and 2‐methylquinoxaline.

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Studies on the magnetic cross-over in five-co-ordinate complexes of iron(II), cobalt(II), and nickel(II). Part II

Cited by 108 publications

References 0 publications

η1- and η3-Allylpalladium(II) Complexes Bearing Potentially Tridentate Ligands: Synthesis, Solution Dynamics, and Crystal Structures

η1- and η3-Allylpalladium(II) Complexes Bearing Potentially Tridentate Ligands: Synthesis, Solution Dynamics, and Crystal Structures

Neutral Tridentate PNP Ligands and Their Hybrid Analogues: Versatile Non‐Innocent Scaffolds for Homogeneous Catalysis

Synthesis and Structural Characterization of Pincer Pyridine Diphosphite Complexes of Rhodium and Iridium

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