Crystal and Electronic Structure of a Mixed-Valent Np(IV)−Np(V) Compound: [BuMeIm]5[Np(NpO2)3(H2O)6Cl12]

• Published in: Inorganic chemistry 2010-03, Vol.49 (5), p.2077-2082
• Main Authors: Charushnikova, Iraida, Bossé, Emilie, Guillaumont, Dominique, Moisy, Philippe
• Format: Article
• Language: English
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/ic901526e

A new mixed valent neptunium compound [BuMeIm]5[Np(NpO2)3(H2O)6Cl12] was synthesized by evaporation of an ethyl acetate−acetone mixture where the salt [BuMeIm]2[NpCl6] was dissolved. The crystal structure was determined using single crystal X-ray diffraction; it consists of four crystallographically unique Np centers with two different coordination environments in two different oxidation states. In addition, five crystallographically independent dialkylimidazolium cations stabilize the crystal through C−H···Cl hydrogen bonds. [Np(NpO2)3(H2O)6Cl12] unit presents a highly symmetric structure with the formation of three Np(IV)−Np(V)O2 + bonds. According to the crystal structure and density functional theory (DFT) calculations, the stability of the three Np4+−NpO2 + interactions is due to the presence of chloride ions around NpO2 + which brings electronic charge into the system and also to the presence of water molecules which create hydrogen bond with chloride ions.