No abstract

The Cover Feature shows an image of the final product of an elaborately designed pincer complex derived from triazolylidene, which has emerged through a long series of steps from the earth′s abundant nickel mines. The complex has interesting properties provided by the ligand with strong σ‐donor and π‐acceptor abilities, and bulky substituents. It is also active in the Suzuki‐Miyaura coupling of aryl bromides. The crystals are called annabergite and are known to be a landmark in nickel mining. Like this crystal, the complex is expected to become one of the landmarks for the development of organonickel chemistry. More information can be found in the Research Article by K. Matsubara and co‐workers.

Tridentate pincer-type triazolylidene nickel(II) complexes have been prepared and characterized. Despite increasing interest in the new series of mesoionic carbene (MIC) ligands in the field of homogeneous catalysis, pincer-type MIC metal complexes have rarely been used as catalysts, and there are few studies on MIC nickel complexes. Herein, MIC nickel(II) halide complexes were synthesized from their silver analogues and fully characterized. An anion exchange reaction with silver tetrafluorobo-rate in acetonitrile gave a dicationic acetonitrile complex in good yield. A comparison of the structures and frontier orbitals between the MIC-and NHC-nickel(II) chloride complexes has revealed that these complexes are comparable in nature. However, their use in the Suzuki-Miyaura (SM) cross-coupling reaction of aryl bromides with phenylboronic acid requires different conditions to provide sufficient results.