Kristallstrukturen von [TiF3(NPPh3)(HNPPh3)]2 und von HNPPh3

Grün, Marion; Harms, Klaus; Köcker, Rolf Meyer zu; Dehnicke, Kurt; Goesmann, Helmut

doi:10.1002/zaac.19966220626

Cited by 24 publications

(5 citation statements)

References 14 publications

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“…To produce compounds 4 , the benzyne that is eliminated upon β-X elimination is trapped by the Ti−N bond in 2X , forming a new Ti−C aryl bond and converting the phosphinimido ligand into a neutral phosphinimine ligand. This is indicated by the significant lengthening of the Ti(1)−N(1) bond to 2.051(2) Å and the bending of the Ti(1)−N(1)−P(1) angle from ∼170 to 139.45(14)°. The 31 P NMR chemical shifts for the phosphinimine ligands of compounds 4 appear at ∼81 ppm, shifted downfield by approximately 24−25 ppm in comparison to the anionic ligands.…”

Section: Resultsmentioning

confidence: 99%

Competitive ArC−H and ArC−X (X = Cl, Br) Activation in Halobenzenes at Cationic Titanium Centers

Piers

Parvez

2006

J. Am. Chem. Soc.

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The titanium methyl cation [Cp*((tBu3P=N)TiCH3]+ [B(C6F5)4]- reacts rapidly with H2 to give the analogous cationic hydride [Cp*((tBu3P=N)TiH(THF)n]+ [B(C6F5)4]- (n = 0, 1), which can be trapped and isolated as its THF adduct 1 x THF (n = 1). When generated in the presence of chloro or bromobenzene, 1 undergoes C-X activation or ortho-C-H activation, depending on the amount of dihydrogen present in the reaction medium. At approximately 4 atm of H2, C-X activation is preferred, giving the halocations [Cp*((tBu3P= N)TiX]+ [B(C6F5)4]- (2X) and C6H6/biphenyl mixtures. At lower pressures of H2 (>1 atm), the beta-halophenyl cations [Cp*((tBu3P=N)Ti(2-X-C6H4)]+ [B(C6F5)4]- (3X) are the products isolated. In the absence of H2, these compounds are quite thermally stable, but undergo beta-halogen elimination upon moderate heating, to give 2X (approximately 20%) and compounds 4X which are the result of reaction between 2X and benzyne via addition of the benzyne C-C triple bond across the Ti-N bond of the phosphinimide ligand. Thus, three separate bond activation processes are operative in this system: direct C-X activation, ortho-C-H activation, and indirect C-X activation via beta-halogen elimination. Mechanistic studies on all three processes have been done and support a radical pathway for direct C-X cleavage, sigma-bond metathesis of the ortho-C-H bond of eta(1)-coordinated C6H5X, and beta-halogen elimination from base-free compound 3X.

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Section: Resultsmentioning

confidence: 99%

Competitive ArC−H and ArC−X (X = Cl, Br) Activation in Halobenzenes at Cationic Titanium Centers

Piers

Parvez

2006

J. Am. Chem. Soc.

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“…21 The PdN [1.605(1) Å] bond distance in 1 is greater than that of the free ligand Ph 3 PNH [1.582(2) Å]. 23 The only other f element complex containing a Ph 3 PNH ligand [Cp* 2 -UCl 2 (Ph 3 PNH)] shows no change upon complexation [PdN, 1.58( 1) Å], despite suggestions that the resonance form, Ph 3 P +-HN -, is stabilized by multiple U-N bond character. 24 (16) [Caution!…”

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confidence: 99%

Preference for Nitrogen versus Oxygen Donor Coordination in Uranyl- and Neptunyl(VI) Complexes

et al. 2005

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The first actinyl phosphinimine complexes have been synthesized and, in the case of uranium, exhibit strong U-N interactions. Competition reactions clearly demonstrate a surprising preference for R3P=NH ligands over R3P=O in the system [AnO2Cl2(R3PX)2] (An = U(VI), Np(VI); R = Ph, Cy; X = O, NH). Spectroscopic evidence for N-donor coordination to [NpO2]2+ in solution indicates chemical similarities to the [UO2]2+ moiety.

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“…The X‐ray crystal structure analysis shows the presence of the endocyclic [P]=N−H phosphinimine moiety (Figure ). Consequently, the P1−N1 bond of 19 is rather short (1.622(1) Å), which is shorter than the corresponding P1−N1 bond of its precursor 18 (1.676(2) Å), but due to its internal borane Lewis acid coordination it is longer than typical phosphinimine P=N− bonds (Ph 3 P=NH 1.524(3) Å) . The B1−N1 bond in 19 is also rather short at 1.581(2) Å: both these values indicate a delocalized structure as described by the mesomeric formulae 19 ↔ 19′ in Scheme .…”

Section: Resultsmentioning

confidence: 92%

The Chemistry of a Non‐Interacting Vicinal Frustrated Phosphane/Borane Lewis Pair

Elmer

Kehr

Daniliuc

et al. 2016

Chemistry A European J

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The dimesitylphosphinocyclopentene/HB(C F ) -derived vicinal trans-1,2-P/B frustrated Lewis pair (FLP) 4 shows no direct phosphane-borane interaction. Toward some reagents it behaves similar to an intermolecular FLP; it cleaves dihydrogen, deprotonates terminal alkynes, and adds to organic carbonyl compounds including CO . It shows typical intramolecular FLP reaction modes (cooperative 1,1-additions) to mesityl azide, to carbon monoxide, and to NO. The latter reaction yields a persistent P/B FLPNO nitroxide radical, which undergoes H-atom abstraction reactions. The FLP 4 serves as a template for the CO reduction by [HB(C F ) ] to generate a FLP-η -formylborane. The formylborane moiety is removed from the FLP template by reaction with pyridine to yield a genuine pyridine stabilized formylborane that undergoes characteristic borane carbaldehyde reactions (Wittig olefination, imine formation). Most new products were characterized by X-ray diffraction.

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Kristallstrukturen von [TiF₃(NPPh₃)(HNPPh₃)]₂ und von HNPPh₃

Cited by 24 publications

References 14 publications

Competitive ArC−H and ArC−X (X = Cl, Br) Activation in Halobenzenes at Cationic Titanium Centers

Competitive ArC−H and ArC−X (X = Cl, Br) Activation in Halobenzenes at Cationic Titanium Centers

Preference for Nitrogen versus Oxygen Donor Coordination in Uranyl- and Neptunyl(VI) Complexes

The Chemistry of a Non‐Interacting Vicinal Frustrated Phosphane/Borane Lewis Pair

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