Facile N-functionalization and strong magnetic communication in a diuranium(v) bis-nitride complex. Issue 12 (18th February 2019)

• Record Type: Journal Article
• Authors: Barluzzi, Luciano; Chatelain, Lucile; Fadaei-Tirani, Farzaneh; Zivkovic, Ivica; Mazzanti, Marinella
• Is Part Of: Chemical science. Volume 10:Issue 12(2019)
• Page Start: 3543
• Page End: 3555
• Publication Date: 2019-02-18
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c8sc05721d
• Languages: English
• ISSNs: 2041-6520

Abstract

Abstract : A diuranium(v ) bis-nitride complex supported by siloxide ligands displays remarkable reactivity in ambient conditions with small molecules such as CS2, CO2, CO and H2 resulting in N–C and N–H bond formation. The nitride linker also leads to an unusually strong antiferromagnetic coupling between uranium(v ) ions. Abstract : Uranium nitride complexes are of high interest because of their ability to effect dinitrogen reduction and functionalization and to promote magnetic communication, but studies of their properties and reactivity remain rare. Here we have prepared in 73% yield the diuranium(v ) bis-nitride complex [K2 {[U(OSi(O t Bu)3 )3 ]2 (μ-N)2 }], 4, from the thermal decomposition of the nitride-, azide-bridged diuranium(iv ) complex [K2 {[U(OSi(O t Bu)3 )3 ]2 (μ-N)(μ-N3 )}], 3. The bis-nitride4 reacts in ambient conditions with 1 equiv. of CS2 and 1 equiv. of CO2 resulting in N–C bond formation to afford the diuranium(v ) complexes [K2 {[U(OSi(O t Bu)3 )3 ]2 (μ-N)(μ-S)(μ-NCS)}], 5 and [K2 {[U(OSi(O t Bu)3 )3 ]2 (μ-N)(μ-O)(μ-NCO)}], 6, respectively. Both nitrides in4 react with CO resulting in oxidative addition of CO to one nitride and CO cleavage by the second nitride to afford the diuranium(iv ) complex [K2 {[U(OSi(O t Bu)3 )3 ]2 (μ-CN)(μ-O)(μ-NCO)}], 7 . Complex4 also effects the remarkable oxidative cleavage of H2 in mild conditions to afford the bis-imido bridged diuranium(iv ) complex [K2 {[U(OSi(O t Bu)3 )3 ]2 (μ-NH)2 }], 8 that can be further protonated to afford ammonia in 73% yield. Complex8 provides a good model for hydrogen cleavage by metal nitrides in the Haber–Bosch process. The measured magnetic data show an unusually strong antiferromagnetic coupling between uranium(v ) ions in the complexes4 and6 with Neel temperatures of 77 K and 60 K respectively, demonstrating that nitrides are attractives linkers for promoting magnetic communication in uranium complexes.