Substituted diaryldiazomethanes and diazofluorenes: structure, reactivity and stability

Davis, Philip J.; Harris, Lawrence D.; Karim, Aman; Thompson, Amber L.; Gilpin, Martin L.; Moloney, Mark G.; Pound, Matthew J.; Thompson, Claire

doi:10.1016/j.tetlet.2011.01.116

Cited by 37 publications

(40 citation statements)

References 39 publications

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“…The relative reactivity of the four diaryldiazomethane systems was found to conform to that observed in a related set of systems recently reported by us, 23 for which electron releasing groups were shown to lower the temperature of diaryldiazomethane decomposition. The relative reactivity of the four diaryldiazomethane systems was found to conform to that observed in a related set of systems recently reported by us, 23 for which electron releasing groups were shown to lower the temperature of diaryldiazomethane decomposition.…”

Section: Resultssupporting

confidence: 85%

Sidewall functionalisation of carbon nanotubes by addition of diarylcarbene derivatives

et al. 2011

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Section: Resultssupporting

confidence: 85%

Sidewall functionalisation of carbon nanotubes by addition of diarylcarbene derivatives

et al. 2011

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“…[13] In this case, along with 2 and 2,2Ј-bipyridine was formed a small amount of the previously synthesized Tp*U(dmpz) 3 (dmpz = 3,5-dimethylpyrazolide). Distances for the same bonds in the uncoordinated diazoalkanes range from 1.130-1.145 Å (N-N) and 1.28-1.32 Å (C-N), [28][29][30] which indicates that the diazoalkane has been significantly reduced by interaction with the uranium center; a hydrazonido ligand, [N 2 CPh 2 ] 2-, is formed. [14] In our hands, thermal decomposition of bis-Tp* U IV complexes with uranium-nitrogen multiple bonds also produces Tp*U(dmpz) 3 .…”

Section: Resultsmentioning

confidence: 99%

Diazoalkane Reduction for the Synthesis of Uranium Hydrazonido Complexes

2012

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The reactivity of the uranium(III) alkyl Tp*2UCH2Ph (1) toward diazoalkanes is reported. Addition of 1 equiv. N2CPh2 produces 0.5 equiv. bibenzyl, along with Tp*2U(N2CPh2) (2). This species is dynamic in solution at room temperature and rapidly interconverts between the η1‐ and η2 isomers as determined by variable‐temperature 1H NMR spectroscopy. X‐ray crystallographic analysis at low temperature shows exclusively the η2 isomer, which features a short U–N multiple bond analogous to an imido species. The η1 isomer reacts quantitatively with aldehydes and ketones through multiple bond metathesis to produce Tp*2U(O) and the corresponding ketazine. Treatment of 1 with N2CHSiMe3 generates 0.5 equiv. bibenzyl and the η1 isomer Tp*2U(N2CHSiMe3) (3). This species is unstable over the course of hours, and there is no spectroscopic evidence for the η2 isomer. Tp*2U(η1‐N2CHSiMe3) can be trapped by addition of phenylacetylene by a [2+2] cycloaddition to afford the uranium(IV) metallacycle Tp*2U[(N‐N = CHSiMe3)CHCPh] (4). Crystallographic data for 4 are presented.

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“…Compound L2 was prepared by subjecting the respective thioketone [2d] and diazo [24] precursors to aB arton-Kellogg coupling in refluxing THF (see the Supporting Information for details). Theproduct, isolated in 52 %yield as aracemate, was subsequently stirred under reflux in ethanol with cis-[Ru(bpy) 2 Cl 2 ].…”

Section: Osmentioning

confidence: 99%

Visible‐Light‐Driven Photoisomerization and Increased Rotation Speed of a Molecular Motor Acting as a Ligand in a Ruthenium(II) Complex

2015

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Toward the development of visible-light-driven molecular rotary motors, an overcrowded alkene-based ligand and the corresponding ruthenium(II) complex is presented. In our design, a 4,5-diazafluorenyl coordination motif is directly integrated into the motor function. The photochemical and thermal isomerization behavior has been studied by UV/Vis and NMR spectroscopy. Upon coordination to a Ru(II) bipyridine complex, the photoisomerization process can be driven by visible (λmax = 450 nm) instead of UV light and furthermore, a large increase of the speed of rotation is noted. DFT calculations point to a contraction of the diazafluorenyl lower half upon metal-coordination resulting in reduced steric hindrance in the "fjord region" of the molecule. Consequently, it is shown that metal-ligand interactions can play an important role in the adjustment of both photophysical and thermodynamic properties of molecular motors.

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Substituted diaryldiazomethanes and diazofluorenes: structure, reactivity and stability

Cited by 37 publications

References 39 publications

Sidewall functionalisation of carbon nanotubes by addition of diarylcarbene derivatives

Sidewall functionalisation of carbon nanotubes by addition of diarylcarbene derivatives

Diazoalkane Reduction for the Synthesis of Uranium Hydrazonido Complexes

Visible‐Light‐Driven Photoisomerization and Increased Rotation Speed of a Molecular Motor Acting as a Ligand in a Ruthenium(II) Complex

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