Reversible Halide-Modulated Nickel–Nickel Bond Cleavage: Metal–Metal Bonds as Design Elements for Molecular Devices


  • We thank Lawrence M. Henling for assistance with collection of crystallographic data. We are grateful to NSF GRFP (S.L.), Caltech, SURF office (N.C.L.), and bp for funding. The Bruker KAPPA APEXII X-ray diffractometer was purchased through an NSF CRIF:MU Award to Caltech (CHE-0639094). The 400 MHz NMR spectrometer was purchased through an NIH award, RR027690.


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The dinickel chloride affair: In dinuclear nickel(I) complexes supported by a tris(phosphinoaryl)benzene and stabilized by metal–arene interactions, chloride addition causes reversible Ni[BOND]Ni bond cleavage that induces 180° rotation around an aryl–aryl bond (see scheme). A dinickel–chloride moiety was found to rotate around the bridging arene by a mechanism involving breaking and forming Ni[BOND]P bonds.