Assembling diuranium complexes in different states of charge with a bridging redox-active ligand

Abstract

Radical-bridged diuranium complexes are desirable for their potential high exchange coupling and single molecule magnet (SMM) behavior, but remain rare. Here we report for the first time radical-bridged diuranium(IV) and...

Multimetallic Uranium Nitride Cubane Clusters from Dinitrogen Cleavage

“…69,70,65 Variable-temperature X-band EPR measurements performed on frozen 2-methyltetrahydrofuran solutions of 2 showed that the complex is EPR-silent at room temperature as well as at 6 K. Similarly, the radical-bridged U(IV)/U(IV) diuranium complex [{((Me 3 Si) 2 N) 3 U IV } 2 (μ-bpym)][BPh 4 ] did not show any EPR signal at 6 K or at RT. 71 Several mononuclear uranium(IV) radical species, such as [{(SiMe 2 NPh) 3 -tacn}-U IV (η 2 -N 2 Ph 2 )] 65 and [(( t-Bu ArO) 3 tacn)U IV (η 2 -NNCPh 2 )] (tacn = 1,4,7-triazacyclononane), 72 also lack EPR features.…”

Actinide-based single-molecule magnets: alone or in a group?

“…(35c), and [{((Me 3 Si) 2 N) 3 U(IV)} 2 (μ-bpym)][BPh 4 ] (35d), 57 showing analogous structures but different metrical parameters. Complexes 35b and 35d present radical-bridged U(III)-bpym •− -U(III) and U(IV)-bpym •− -U(IV) cores, respectively.…”

“…Recently, Mazzanti et al reported a series of bpym-bridged diuranium complexes (Fig. 11), [{((Me 3 Si) 2 N) 3 U( iv )} 2 (μ-bpym)] ( 35a ), [K(2.2.2-cryptand)][{((Me 3 Si) 2 N) 3 U( iii )} 2 (μ-bpym)] ( 35b ), [K(2.2.2-cryptand)] 2 [{((Me 3 Si) 2 N) 3 U( iii )} 2 (μ-bpym)] ( 35c ), and [{((Me 3 Si) 2 N) 3 U( iv )} 2 (μ-bpym)][BPh 4 ] ( 35d ), 57 showing analogous structures but different metrical parameters. Complexes 35b and 35d present radical-bridged U( iii )–bpym˙ − –U( iii ) and U( iv )–bpym˙ − –U( iv ) cores, respectively.…”

A trinuclear metallasilsesquioxane of uranium(iii)

“…The design of polymetallic assemblies is attracting high interest in uranium chemistry because of their ability to promote small molecule activation, [1][2][3][4][5][6][7][8][9][10] and their interesting magnetic properties, [11][12][13][14][15] yet synthetic routes to such assemblies remain elusive. Moreover, the recent identification of the first example of actinide metal-metal bonding interactions in a trinuclear thorium complex 16,17 suggests that trinuclear assemblies may be used to promote metal-metal interactions in uranium compounds.…”

“…To further confirm that N 2 activation had occurred the reaction was also performed with labelled 15 N 2 (Fig. S19, ESI †) yielding the distinctive signals of 15 NH 4 Cl after quenching. The observed reduction of N 2 by the complex 1 in the presence of KC 8 suggests that N 2 binding to the uranium centres must occur to some extent also in thf solution, but could not be detected by 1 H NMR spectroscopy.…”