Dinuclear uranium complexation and manipulation using robust tetraaryloxides

Wells, J.A.; Seymour, Megan L.; Suvova, Markéta; Arnold, Polly L.

doi:10.1039/c6dt02630c

Cited by 13 publications

(22 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The anion of the meta-tetraphenol-arene H 4 (mTP) binds Lewis acidic metal cations via strong M-O bonds; 37 1:1 reactions with U IV or Th IV form rectangular metallacyclic M 2 (mTP) 2…”

Section: Resultsmentioning

confidence: 99%

Metallacyclic actinide catalysts for dinitrogen conversion to ammonia and secondary amines

et al. 2020

Self Cite

View full text Add to dashboard Cite

Chemists have spent over a hundred years trying to make ambient temperature/pressure catalytic systems that could convert atmospheric dinitrogen to ammonia, or to directly to amines. A handful of successful d-block metal catalysts have been developed in recent years, but even binding of dinitrogen to an f-block metal cation is extremely rare. Here we report the first f-block complexes that can catalyse the reduction and functionalisation of molecular dinitrogen, and the first catalytic conversion of molecular dinitrogen to a secondary silylamine. Simple bridging ligands assemble two actinide metal cations into narrow dinuclear metallacycles that can trap the diatom while electrons from an externally-bound group 1 metal, and protons or silanes, are added enabling N 2 to be functionalised with modest but catalytic yields of six equivalents of secondary silylamine per molecule at ambient temperature and pressure.Many complexes of the d-block metals can bind the abundant dinitrogen molecule, but the conversion to products is very difficult, and only a few are capable of catalytic conversion. The most successful catalysts are based on Mo or Fe 1,2,3,4,5,6,7,8 , and convert the bound dinitrogen to NH 3 or N(SiMe 3 ) 3 , using compatible sources of reducing equivalents and protons or silyl electrophiles (e.g. KC 8 powder and lutidinium borates or Me 3 SiCl) 9,10 . The use of soluble metal catalysts offers direct routes to other functionalised organo-nitrogen molecules and further insight into the workings of the exceptional heterogeneous Haber-Bosch catalyst or the low-energy nitrogenase enzymes that directly make ammonia. 11,12,13,14,15,16,17 An emerging key feature of some of the most successful homogeneous systems is the ability of the complex to incorporate alkali metal cations that bring the reducing electrons to the nitrogen centres, providing additional coulombic interactions, and the capacity of the resulting multi-metallic framework to flex sufficiently to enable the N 2 coordination mode to change during reduction. 18,19,20,21,22 Binding of dinitrogen by any f-block metal ion is extremely rare. 23,24 The eight known actinide-dinitrogen complexes were all made by exploiting the strongly reducing

show abstract

“…The anion of the meta-tetraphenol-arene H 4 (mTP) binds Lewis acidic metal cations via strong M-O bonds; 37 1:1 reactions with U IV or Th IV form rectangular metallacyclic M 2 (mTP) 2…”

Section: Resultsmentioning

confidence: 99%

Metallacyclic actinide catalysts for dinitrogen conversion to ammonia and secondary amines

et al. 2020

Self Cite

View full text Add to dashboard Cite

show abstract

“…Our previous electrochemical analyses of the free ligand, and the potassium salt, were not helpful. 39 The couples can be compared to a range of related O-ligated Ce IV complexes such as [Ce(O t Bu) 4 ( py) 2 ] (E pc = −1.99 V vs. Fc/ Fc + in DCM), 40 Ce(2-( t BuNO)py) 4 (E pc = −1.95 V vs. Fc/Fc + in DCM), 12,40 CeL(O t Bu) 4 (E pc = −2.39 V vs. Fc/Fc + in THF) 9 and imidophosphorane supported complexes Ce(NPPip 3 ) 4 (reduction range of −2.30 < E pc < −2.47 V vs. Fc/Fc + in THF). 10 In order to obtain a more chemically accurate view on the Ce complex oxidation state, HERFD-XAS (high energy resolution fluorescence detection X-ray absorption spectroscopy) was employed.…”

Section: Redox Chemistrymentioning

confidence: 99%

Dicerium letterbox-shaped tetraphenolates: f-block complexes designed for two-electron chemistry

et al. 2020

Self Cite

View full text Add to dashboard Cite

show abstract

“…Each uranium centre is ligated by one end of a bridging dioxane molecule in an axial position with a U-O distance of 2.577(3) Å, which is considerably longer than in [UI 4 (1,4dioxane) 2 ] or the [UI 2 (dioxane) 2 (aryloxide)] previously reported by our group (mean = 2.333(6) Å and 2.087 Å respectively). [14][15][16] The boroxide ligands in the equatorial positions have a U-O avg distance of 2.144(3) Å, which is shorter than in the uranium(III) complex 1 m , consistent with a U IV centre, and similar to the U-O bond length for [U(OBTrip) 4 ] with a U-O distance of 2.159(5) Å. The boroxide ligands in the axial positions have a U-O distance of 2.095(3) Å, which is much shorter than the equatorial boroxides.…”

Section: Crystallographymentioning

confidence: 99%

Applications of boroxide ligands in supporting small molecule activation by U(iii) and U(iv) complexes

et al. 2019

Self Cite

View full text Add to dashboard Cite

show abstract

Dinuclear uranium complexation and manipulation using robust tetraaryloxides

Abstract: Two lower-oxidation state uranium cations can be readily combined in a robust, yet flexible and derivatisable, tetraaryloxide ligand framework, affording a new platform at which to use the multi-electron reductive capacity of the two actinide centres.

Cited by 13 publications

References 34 publications

Metallacyclic actinide catalysts for dinitrogen conversion to ammonia and secondary amines

Metallacyclic actinide catalysts for dinitrogen conversion to ammonia and secondary amines

Dicerium letterbox-shaped tetraphenolates: f-block complexes designed for two-electron chemistry

Applications of boroxide ligands in supporting small molecule activation by U(iii) and U(iv) complexes

Contact Info

Product

Resources

About