A Nickel(II)-Cornered Molecular Rectangle with Biscarbene and 4,4′-Bipyridine Bridging Groups

Nickelocene reacts with a rigid bisimidazolium salt to give cyclopentadiene and a biscarbene-bridged dinuclear nickel complex, which upon treatment with 4,4'-bipyridine and AgBF4 yields the CpNiII-cornered molecular rectangle [1](BF4)(4).