Double dative bond between divalent carbon(O) and uranium

Dative bonds between p- and d-block atoms are common but species containing a double dative bond, which donate two-electron pairs to the same acceptor, are far less common. The synthesis of complexes between UCl4 and carbodiphosphoranes (CDP), which formally possess double dative bonds Cl4U paired left arrows CDP, is reported in this paper. Single-crystal X-ray diffraction shows that the uranium-carbon distances are in the range of bond lengths for uranium-carbon double bonds. A bonding analysis suggests that the molecules are uranium-carbone complexes featuring divalent carbon(O) ligands rather than uranium-carbene species. The complexes represent rare examples with a double dative bond in f-block chemistry. Our study not only introduces the concept of double dative bonds between carbones and f-block elements but also opens an avenue for the construction of other complexes with double dative bonds, thus providing new opportunities for the applications of f-block compounds.