A new clover-shaped trinuclear uranium(VI) complex: Synthesis, structure and photoluminescence property

A new clover-shaped trinuclear uranium(VI) complex of the formula [(UO2)3(phen)3(μ3-O)(μ2-OH)2(NO2)]·NO3·3DMF·H2O (1) (phen = 1,10-phenanthroline, DMF = N,N′-dimethylformamide) was prepared by reaction of UO2(NO3)2·6H2O and phen under ultrasonic condition. X-ray single-crystal diffraction analysis shows that each U(VI) ion is in a seven-coordinated pentagonal–bipyramidal environment, with two O atoms in axial positions forming a uranyl ion. Each uranyl ion in 1 is coordinated by one chelating phen ligand and three O atoms at the equatorial plane. Interestingly, one central μ3-oxo incorporates two μ2-OH− and one NO2− to link uranyl ions into a clover-shaped motif. The molecules of 1 are packed within the space through hydrogen bonds, π···π and lone-pair···π interactions. The solid diffuse-reflectance UV/vis and photoluminescence spectra of 1 were measured and discussed.