Theoretical investigation of the reactivity of bispentamethylcyclopentadienyl uranium(IV) bisthiolate complexes with the heteroallene molecules CS2 and CO2

Comparative Insertion Reactivity of CO, CO2, tBuCN, and tBuNC into Thorium– and Uranium–Phosphorus Bonds

“…Insertion reactions with small molecules are some of the most common reaction pathways for these substrates, especially with weak metal–ligand bonds. While the insertion of CO, − CO 2 , − isocyanides, − and nitriles − with actinide complexes that contain bonds with the harder, first-row main-group elements are well-established, those of complexes containing soft donors, such as phosphorus, − are less established. In this case, the mismatch of the hard metal and soft donor ligand can lead to novel reactivity patterns with respect to small-molecule activation, since the soft donor ligand can give rise to a metal center more reactive than that with its 2p congener, nitrogen.…”

How the Ancillary Ligand X Drives the Redox Properties of Biscyclopentadienyl Pentavalent Uranium Cp2U(═N–Ar)X Complexes

“…This is presumably because of the lack of metal-to-ligand backdonating effect within the imide UN−C Ar coordination for the oxidized U VI (5f 0 ) cationic species. Indeed, keeping in mind that the U(V) LUMO and SOMO are pure metallic 5f MO during the reduction process, the UN imide bond length gets longer when passing from the neutral U(V) to the anionic U(IV) species as a result of the uranium ionic radii variation, 62 accompanied by the N−C Ar shortening, as shown in Table 1. This latter result is likely to follow from the weak back-donating effect consecutive to the metal−ligand UN bond lengthening.…”

“…The U­[5d] valence space of the heavy element includes the 5f/6s/6p/6d/7s/7p shells (14 valence electrons). Several studies have shown that the ZORA/BP86/TZP approach reproduces the experimental geometries and ground-state properties of f-element compounds with a satisfying accuracy. − ,, In our case, we carried out first the full geometry optimizations of the species under consideration, in the gas phase, at the spin unrestricted level. Next, the geometries were re-optimized in the THF solvent using the COSMO model.…”

“…For instance, it is likely that the more pronounced covalent character of the actinide−ligand bonds than lanthanide−ligand ones, involving the 5f electrons will play a role on their electrochemical properties. 4,5,17,18,22 In view of the rich diversity of organo−uranium complexes and the importance of the redox chemistry in the reactivity processes, 17,18,27,30,35,61,62 the aim of this work is to investigate the redox properties not only to get access theoretically to the electrochemical potentials but also to corelate these properties to the ligand's nature. The target systems are the series of pentavalent bis(cyclopentadienyl) imido-uranium(V) Cp 2 U( N−Ar)X complexes derived from [(C 5 Me 5 ) 2 U V (N−Ar)(X)] (Ar = 2,6-i Pr 2 -C 6 H 3; X = OTf, SPh, NPh 2 , OPh, Me, Ph, C CPh, NCPh 2 ) complexes (Figure 1), synthetized by the Kiplinger's group, 38,39 for which U V /U IV and U VI /U V redox (E 1/2 ) half-wave potentials have been measured for almost all of them.…”