Identification of the U(v) complex (C₅Me₅)₂U^VI(NSiMe₃) in the reaction of (C₅Me₅)₂U^IIII(THF) with N₃SiMe₃

Abstract

The U(V) imido complex (C5Me5)2UVI(=NSiMe3), 1, was crystallographically characterized from the reaction of (C5Me5)2UIIII(THF) with N3SiMe3 which demonstrates that it can be an intermediate in the reaction which ultimately forms...

Investigating the reactivity of a Lewis base-supported terminal uranium imido metallocene

“…Terminal imido organoactinide complexes featuring an AnN double bond have been studied for more than four decades because of their potential applications in small molecule activation and/or catalysis. 1–4 Despite these efforts and plenty of gathered structural information, the influence of small structural changes on the structure–reactivity relationship still leaves room for further exploration. 2–4 This also aligns well with the central themes in organoactinide chemistry, that is, small molecule activation 5 and the even more fundamental question of to what extent the 6d and 5f orbitals are involved in metal–ligand bonding and how this influences the reactivity of these complexes.…”

“…1–4 Despite these efforts and plenty of gathered structural information, the influence of small structural changes on the structure–reactivity relationship still leaves room for further exploration. 2–4 This also aligns well with the central themes in organoactinide chemistry, that is, small molecule activation 5 and the even more fundamental question of to what extent the 6d and 5f orbitals are involved in metal–ligand bonding and how this influences the reactivity of these complexes. 6 Our contributions to this area have focused on thorium and uranium complexes containing metal–ligand multiple bonds and their intrinsic reactivity, 7 and in our most recent contribution, we detail the reactivity of [η 5 -1,2,4-(Me 3 Si) 3 C 5 H 2 ] 2 UN( p -tolyl)(dmap) 8 a – c with a wide range of small organic substrates such as alkynes, isothiocyanates, amidates, organic nitriles and imines, chlorosilanes, copper iodide, diphenyl disulfide, organic azides and diazoalkane derivatives.…”

Uranium versus Thorium: A Case Study on a Base-Free Terminal Uranium Imido Metallocene

“…Actinide complexes with a terminal imido AnNR functionality have been studied in detail, because of their involvement in small molecule activation and/or catalysis. − Besides these more applied reactivity aspects, research in this part of the periodic table is also motivated by a more fundamental question concerning the impact of 6d and 5f orbitals on bonding and reactivity . Both aspects are essential to establish a structure–reactivity relationship, − which may also expand the general utility of organoactinides in transformations involving small organic and inorganic compounds .…”

“…Actinide complexes with a terminal imido AnNR functionality have been studied in detail, because of their involvement in small molecule activation and/or catalysis. − Besides these more applied reactivity aspects, research in this part of the periodic table is also motivated by a more fundamental question concerning the impact of 6d and 5f orbitals on bonding and reactivity . Both aspects are essential to establish a structure–reactivity relationship, − which may also expand the general utility of organoactinides in transformations involving small organic and inorganic compounds . This led to the synthesis and structural characterization of a large number of actinide imido compounds and several studies implied that small changes in the 5f orbital contributions besides steric effects may also have a pronounced impact on the reactivity of organoactinide compounds. − We have been interested in the preparation and reactivity of thorium and uranium complexes featuring actinide-element multiple bonds for many years, , and, as part of these studies, we also established some significant differences in the reactivity of thorium and uranium phosphinidene, − which are, e.g., exemplified by the fact that the phosphinidene moiety in [η 5 -1,2,4-(Me 3 C) 3 C 5 H 2 ] 2 ThP-(2,4,6-(Me 3 C) 3 C 6 H 2 ) acts as a nucleophile toward heterounsaturated molecules or as a strong base inducing the intermolecular C–H bond activations, , whereas the related uranium complex [η 5 -1,2,4-(Me 3 C) 3 C 5 H 2 ] 2 UP-(2,4,6-(Me 3 C) 3 C 6 H 2 ) serves as a synthetically useful synthon for the [η 5 -1,2,4-(Me 3 C) 3 C 5 H 2 ] 2 U­(II) fragment when reacted with unsaturated molecules .…”

Reactivity Studies on the Lewis Base-Supported Terminal Uranium Imido Metallocene [η5-1,3-(Me3C)2C5H3]2U═N(p-tolyl)(dmap)

“…Actinide complexes featuring terminal imido groups An = NR have now been studied for more than four decades. − These investigations have been centered not only around structural aspects but also on their utility in small-molecule functionalization and to engage in catalytic processes. − Despite these efforts, small modifications in the supporting ligand architecture modulate the structure–reactivity relationship in these systems, which still leaves room for further systematic explorations. Besides pure reactivity aspects, a fundamental, yet controversial question in organoactinide chemistry is the question of covalence and the contribution of 6d and 5f orbitals to the metal–ligand bond .…”