Synthesis and activation potential of an open shell diphosphine

Helmdach, Kai; Ludwig, Stephan; Villinger, Alexander; Hollmann, Dirk; Kösters, Jutta; Seidel, Wolfram W.

doi:10.1039/c7cc02114c

Cited by 16 publications

(22 citation statements)

References 49 publications

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“…Intramolecular oxidation of W II by the terminal carbeniumc entre could lead to ab iradical or triplet state which is NMR silent. [15,[34][35][36] The existence of at ungsten-based S = 1/2 system was confirmed by an EPR experiment. The Xb and spectrum in solution (see Supporting Information, Figure S1) displayed ani sotropic hyperfine coupling A I = 26 10 À4 cm À1 to 127 I( I = 5/2, 100 %) centreda t< g > = 2.003, while signs for an additional organic radicalw ere missing.…”

Section: Cyclization Mechanismmentioning

confidence: 76%

“…[23] We did not observe any phosphorus based spin density,w hich is confirmed by the fact that the W III complex [Tp*W(CO)I{h 2 -C 2 (PPh 2 ) 2 }](BF 4 )c ould be isolated and fully characterized. [34] Accordingly, the W(II/III) redox potential lies between those of the carbenium ion and the phosphine.…”

Section: Discussionmentioning

confidence: 99%

“…[Tp*W(CO)I(HC 2 H)] (1)a nd [Tp*W(CO)I(Ph 2 PC 2 H)] (2)w ere prepared according to literature methods. [34] NMR spectra were recorded at 300 Ku sing Bruker Avance2 50, 300 or 500 MHz spectrometers. In 1 Ha nd 13 CNMR the chemical shifts are internally referenced to the solvent residual peak.…”

Section: Methodsmentioning

confidence: 99%

“…Solvents were dried and saturated with argon by standard methods and freshly distilled prior to use. [Tp*W(CO)I(HC 2 H)] ( 1 ) and [Tp*W(CO)I(Ph 2 PC 2 H)] ( 2 ) were prepared according to literature methods . NMR spectra were recorded at 300 K using Bruker Avance 250, 300 or 500 MHz spectrometers.…”

Section: Methodsmentioning

confidence: 99%

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Facile Synthesis of a Stable Side‐on Phosphinyne Complex by Redox Driven Intramolecular Cyclisation

Lange

Schröder

Oberem

et al. 2020

Chemistry A European J

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Alkyne complexes with vicinal substitution by a Lewis acid and a Lewis base at the coordinated alkyne are prospective frustrated Lewis pairs exhibiting a particular mutual distance and, hence, a specific activation potential. In this contribution, investigations on the generation of a WII alkyne complex bearing a phosphine as Lewis base and a carbenium group as Lewis acid are presented. Independently on potential substrates added, an intramolecular cyclisation product was always isolated. A subsequent deprotonation step led to an unprecedented side‐on λ5‐phosphinyne complex, which is interpreted as highly zwitterionic according to visible absorption spectroscopy supported by TD‐DFT. Low‐temperature 31P NMR and EPR spectroscopic measurements combined with time‐dependent IR‐spectroscopic monitoring provided insights in the mechanism of the cyclisation reaction. Decomposition of the multicomponent IR spectra by multivariate curve resolution and a kinetic hard‐modelling approach allowed the derivation of kinetic parameters. Assignment of the individual IR spectra to potential intermediates was provided by DFT calculations.

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Section: Cyclization Mechanismmentioning

confidence: 76%

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 2 more Smart Citations

Facile Synthesis of a Stable Side‐on Phosphinyne Complex by Redox Driven Intramolecular Cyclisation

Lange

Schröder

Oberem

et al. 2020

Chemistry A European J

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“…Interestingly, no incorporation of deuterium into trans and geminal positions of vinyltungsten complex 157 was observed in the reaction of acetylene with tungsten complex WDCp(CO) 3 ( Scheme 82 ). Tungsten complexes with diphosphines [Tp*W(CO)(I){ η 2 -C 2 (PPh 2 ) 2 }] (Tp* = hydrido-tris(3,4,5-trimethyl-pyrazolyl)borate) showed highly reversible redox potentials [ 190 ]. A variety of substituted bisphosphine acetylene bridged dinuclear complexes with a side-on bound Tp*W(CO)(I) moiety and a chelate-like coordinated PtCl 2 unit was reported [ 191 ].…”

Section: Acetylene In Organic Synthesismentioning

confidence: 99%

Acetylene in Organic Synthesis: Recent Progress and New Uses

et al. 2018

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Recent progress in the leading synthetic applications of acetylene is discussed from the prospect of rapid development and novel opportunities. A diversity of reactions involving the acetylene molecule to carry out vinylation processes, cross-coupling reactions, synthesis of substituted alkynes, preparation of heterocycles and the construction of a number of functionalized molecules with different levels of molecular complexity were recently studied. Of particular importance is the utilization of acetylene in the synthesis of pharmaceutical substances and drugs. The increasing interest in acetylene and its involvement in organic transformations highlights a fascinating renaissance of this simplest alkyne molecule.

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Boosting the Donor Effect of Side‐On W(II) Alkyne Complex Based Diphosphines

et al. 2022

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Redox-active tungsten alkyne complex-based phosphines of the type [Tp*W(CO)Br(η 2 -C 2 (PR 2 ) x ] (x = 1, 2; R = Ph, i-Pr) and coordination experiments with the corresponding diphosphines are described. The pK B values of the terminal free phosphine groups were estimated indirectly by the 1 J P/Se coupling constants in the associated P-selenides. A ten orders of magnitude higher basicity for the bis(diisopropyl)phosphine derivatives compared to the diphenyl congener as well as a significant difference in basicity of the phosphine depending on its position at the alkyne was determined. The diphosphines were utilized for comparative coordination experiments with Ni(II) and Cu(I) as first row transition metals. The heterobimetallic complexes {[Tp*W(CO)Br(μ-η 2 -C,C'-k 2 -P,P'-C 2 (PR 2 ) 2 ]NiCl 2 } (R = Ph, i-Pr) were synthesized and fully characterized, the large difference in basicity and donor strength being underlined by a different degree of stability. Furthermore, two Cu(I) complexes of the isopropyl diphosphine derivative are presented and discussed; one of both being a dinuclear phenanthroline Cu(I) complex and the other a tetranuclear complex exhibiting an angled Cu 2 Br + core.

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Synthesis and activation potential of an open shell diphosphine

Cited by 16 publications

References 49 publications

Facile Synthesis of a Stable Side‐on Phosphinyne Complex by Redox Driven Intramolecular Cyclisation

Facile Synthesis of a Stable Side‐on Phosphinyne Complex by Redox Driven Intramolecular Cyclisation

Acetylene in Organic Synthesis: Recent Progress and New Uses

Boosting the Donor Effect of Side‐On W(II) Alkyne Complex Based Diphosphines

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