Proton sponge phosphines: electrospray-active ligands

Farrer, Nicola J.; McDonald, Robert; McIndoe, J. Scott

doi:10.1039/b609561e

Cited by 44 publications

(48 citation statements)

References 62 publications

(58 reference statements)

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“…Their findings explain some general mechanistic findings in palladium cross coupling reactions. Our group's contributions to the area of developing and employing charged and chargeable ESI-MS tags include: the development of various chargeable or charged phosphine ligands analogous to commonly used mono-or bi-dentate neutral phosphine ligands [90][91][92]; using a tethered charged pyridinium group to study distannoxane speciation during esterification catalysis [93]; and examining olefin hydrogenation and silane dehydrocoupling with a charged analogue of Wilkinson's catalyst [91,92].…”

Section: Charged or Chargeable Tagsmentioning

confidence: 99%

The application of electrospray ionization mass spectrometry to homogeneous catalysis

Vikse

Ahmadi

McIndoe

2014

Coordination Chemistry Reviews

116

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Section: Charged or Chargeable Tagsmentioning

confidence: 99%

The application of electrospray ionization mass spectrometry to homogeneous catalysis

Vikse

Ahmadi

McIndoe

2014

Coordination Chemistry Reviews

116

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“…An X-ray crystal structure determination was performed on a single crystal of 3b (Figure 4, CCDC-837947). Comparison of the structure of 3b to that of 3a [14] reveals that the torsion angle reflecting the in-and-out of plane bending of the dimethylamino groups is 22.8°in 3b, significantly less than the 37.4°seen for 3a. The reduced strain is no doubt due to the -PPh 2 group being moved from the proximal 2-to the remote 4-position.…”

Section: Resultsmentioning

confidence: 93%

“…In the reactions with Fe(CO) 5 and W(CO) 5 (thf), 3a coordinated only through the phosphorus atom, and the ESI-MS showed only the expected [M + H] + ions. [14] Reaction of 3a with [Ru(η 6 -p-cymene)-…”

Section: Resultsmentioning

confidence: 99%

“…[14] First studied by Alder and co-workers, Proton Sponge ® (1) is a very strong, non-nucleophilic base (pK a = 12.34 in H 2 O) with high thermodynamic basicity but relatively low kinetic basicity. [15] 1 binds H + by forming intramolecular hydrogen bonds with both nitrogen centers in the molecule to give the charged [N···H···N] + moiety.…”

Section: Introductionmentioning

confidence: 99%

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Proton Sponge Phosphanes: Reversibly Chargeable Ligands for ESI‐MS Analysis

et al. 2011

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Proton sponge phosphanes are unusual ligands in that they possess two basic sites with very different functions: the phosphorus binds to a metal center, while the 1,8‐bis(dimethylamino)naphthalene binds protons strongly. Both groups are selective for their target, and the binding of the proton iseasily reversible by controlling the pH of the solution. Proton sponge phosphanes therefore make useful chargeable ligands for the purposes of electrospray ionization mass spectrometric analysis of the complexes in which they are bound. However, where the 1,8‐bis(dimethylamino)naphthalene is functionalized with the phosphane is critical, and the 1‐dimethylamino group can become involved in binding to the metal when diphenylphosphane is in the 2‐position. This behavior is undesirable from the point of view of keeping proton and metal binding segregated, and we introduce an efficient synthesis of the 4‐substituted proton sponge phosphane in which the two functional groups are on opposite sides of the naphthalene ring. This precaution solves the problem of the molecule acting as a bidentate ligand, but caution is still needed when using the ligand, because ionization pathways such as halide dissociation to form [M – X]+ ions and oxidation of electron‐rich metal complexes to form [M]·+ can be competitive with protonation.

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“…Formally anionic ligands can be lost from the metal center either as radicals, X· (with difficulty), or in combination with another ligand, XY, in a reductive elimination (often a relatively low-energy process). For the most part, the product ion contains the metal, except in special circumstances where a ligand is identifiably the site at which the charge resides [58].…”

Section: Data Interpretationmentioning

confidence: 99%

Gas-phase reactivity of ruthenium carbonyl cluster anions

Henderson

Kwok

McIndoe

2008

J. Am. Soc. Mass Spectrom.

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Partially-ligated anionic ruthenium carbonyl clusters react with alkenes, arenes, and alkanes in the gas phase; the products undergo extensive C-H activation and lose dihydrogen and carbon monoxide under collision-induced dissociation conditions. Triethylsilane and phenylsilane are also reactive towards the unsaturated clusters, and oxygen was shown to rapidly break down the cluster core by oxidative cleavage of the metal-metal bonds. These qualitative gas-phase reactivity studies were conducted using an easily-installed and inexpensive modification of a commercial electrospray ionization mass spectrometer. Interpretation of the large amounts of data generated in these studies is made relatively straightforward by employing energydependent electrospray ionization mass spectrometry (EDESI-MS). here are many examples of reactions between molecules and metal cluster ions in the gas phase, and the area has been well reviewed [1,2]. Of intense current interest are those systems in which catalytic reactions (homogeneous or heterogeneous) are modeled [3,4]. The information gleaned from these studies is particularly advantageous in systems where little or nothing is known about reactivity. Interest in the area stems from the fact that the chemistry of highly reactive, metallic nanoparticles is fundamentally difficult to study, and it is high surface area metals and metal oxides that are responsible for the most industrially important heterogeneous catalytic reactions. Any means of gaining insight into the mechanism of these reactions may prove useful in designing more efficient and more selective catalysts. The absence of surfaces, solvents, and counterions make the gas phase a considerably less complicated environment than that found in solution. Just how good the correspondence is between gas-phase and solution results is subject to active debate [5][6][7], but there is little argument that the gas phase benefits from the reduction in the number of variables, especially when dealing with complicated systems. The gas-phase reactivity of a wide variety of partially ligated clusters have been studied, including oxides [8 -11] [18]. and even some mixed species [19,20]. However, for the most part, the extent of ligation is low and, correspondingly, so is the relevance to solution chemistry. Homogeneous catalysis is generally performed under conditions that are relatively mild and in which the catalysts maintain a (near) complete coordination sphere, so the comparison with nearly naked gas-phase metal clusters is somewhat tenuous (though interestingly, may more closely approximate the conditions of heterogeneous catalysis, which frequently involves unligated metal particles on a surface) [21,22].Some work has also been done on partially ligated carbonyl clusters; an early paper by Ridge [23] example by Ridge demonstrated that in a Fourier transform ion cyclotron resonance mass spectrometer (FTICR-MS), partially ligated cationic transition-metal carbonyl clusters generated by electron ionization reacted readily with cycl...

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Proton sponge phosphines: electrospray-active ligands

Cited by 44 publications

References 62 publications

The application of electrospray ionization mass spectrometry to homogeneous catalysis

The application of electrospray ionization mass spectrometry to homogeneous catalysis

Proton Sponge Phosphanes: Reversibly Chargeable Ligands for ESI‐MS Analysis

Gas-phase reactivity of ruthenium carbonyl cluster anions

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