Complexes of vanadyl and uranyl ions with a benzoxazole derivative: Synthesis, structural features and remarks on luminescence properties

UO2(NO3)2·6H2O and VO(acac)2 react with 2-(2′-hydroxylphenyl)benzoxazole (Hpbx) in methanol to give [UO2(pbx)2(CH3OH)] (1) and [VO(pbx)2] (2). Complex 1 shows a distorted pentagonal bipyrimidal geometry, characteristic for the coordination number 7. Reciprocal OH⋯O interactions between neighbored molecules hold 1 in a pseudo-dimeric association with an inversion center. Complex 2 achieves a distorted octahedral geometry and the molecules “stack” along the b axis through secondary interactions. The molecule heaping is wholly linear, with Vn′−O(1)n′⋯V x′ angles of 180°. Luminescence properties of Hpbx, 1 and 2 are discussed.