Synthesis and characterization of a novel tetranuclear 5f compound: a new synthon for exploring U(IV) chemistry.
In the course of structurally characterizing previously reported complexes based on the 1,2-bis(dimethylphosphino)ethane)) (dmpe) ligand ([(dmpe)(2)UCl(4)] (1) and [(dmpe)(2)UMe(4)] (2)), we find that adjusting the U/dmpe ratio leads to an unprecedented species. Whereas the use of two or three equivalents of dmpe relative to UCl(4) produces 1 as a blue-green solid, the use of a 1:1 dmpe/UCl(4) stoichiometry yields [(dmpe)(4)U(4)Cl(16)]·2CH(2)Cl(2)·(3·2CH(2)Cl(2)) as a green solid. In turn, 3 is used to prepare a mixed-chelating ligand complex featuring the bidentate ligand 4,4'-dimethyl-2,2'-bipyridine (dmbpy), [(dmpe)(dmbpy)UCl(4)] (4). The measured magnetic susceptibilities for 1-4 trend toward nonmagnetic ground states at low temperatures.
Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, USA.
Brian S
BS
Newell
Trevor C
TC
Schwaab
Matthew P
MP
Shores