Heterotrimetallic clusters with U-Ni-Ge and U-Ni-Sn units

Metal-metal bonds in complexes with d-block transition metals are common; but those with metal–metal bonds involving both p-, d-, and f-block metals are extremely rare. Here, we report two examples of heterotrimetallic clusters featuring U-Ni-Ge and U-Ni-Sn units. The heterotrimetallic clusters [(CH2OCH2CH2NPiPr2)2U(µ-Ni)(GePh3)(µ-Cl)]2 (2) and [(CH2OCH2CH2NPiPr2)2U(µ-Ni)(SnPh3)(µ-Cl)]2 (3) were synthesized by the salt elimination reactions of [(CH2OCH2CH2NPiPr2)2UCl(µ-Ni)(µ-Cl)]n (1) with Ph3SnK or Ph3GeLi, respectively. Complexes 2 and 3 were fully characterized by single crystal X-ray diffraction, elemental analysis, UV–Vis-NIR and SQUID. Theoretical studies at the DFT level showed that the Ni-Ge and Ni-Sn bonding interactions are polarized toward Ge and Sn. In both cases, the covalent part of the bonding is controlled by the atomic orbital overlap rather than by the energy difference. This study provides a new opportunity to explore the property of heterometallic clusters with diversified metal–metal bonds.