Uranium(VI) bis(imido) disulfonamide and dihalide complexes: Synthesis density functional theory analysis

Novel cis- and trans-bis(imido) uranium disulfonamide derivatives have been prepared from iodide metathesis reactions between two equivalents of K[N(Me)(SO2Ar')](Ar' = 4-Mc-C6H4) and U((NBu)-Bu-t)(2)(I)(2)(L)(x) (L = OPPh3, x = 2, Me(2)bpy, x= 1; Me-2 bpy = 4,4'-dimethyl-2,2'-bipyridyl). These bis(amide) derivatives serve as useful precursors for the synthesis of the trans-diphenolate complex U(N`Bu)(2)(O-2-(BuC6H4)-Bu-t)(2)(OPPh3)(2) (5), cis- and transdithiolate complexes U((NBu)-Bu-t)(2)(SPh)(2)(L)(x) (L= OPPh3 (6); Me(2)bPY (7)), and cis- and transchhalide complexes with the general formulas U((NBu)-Bu-t)(2)(X)(2)(L)(x) (X = Cl, L= OPPh3 (8), L = Me(2)bpy (10); X = Br, L= OPPh3 (9), L = Me(2)bPv (11)) DFT calculations performed on the trans-dihalide series U((NBu)-Bu-t)(2)(X)(2)(L)(2) and the UO22+ analogues UO2X2(OPPh3)(2) suggest that the uranium centers in the [U((NBu)-Bu-t)(2)](2+) ions possess more covalent character than analogous UO22+ derivatives but that the U-X bonds in the U(NtBu)(2)X2L2 complexes possess a more ionic nature. (C) 2010 Academic des sciences. Published by Elsevier Masson SAS. All rights reserved