Copper(I) Bromide-Mediated Coupling of Imidazoles. Trapping and X-Ray Crystal Structures of the Reaction Intermediates

2008-06-04T00:00:00Z (GMT) by Xue-Feng Huang Da-Wei Fu Ren-Gen Xiong
Solvothermal reaction of 5,10,10-trimethyl-bicyclo[2.2.1]-heptano-2-phenyl imidazole (TBHPI-H) with CuBr as a catalyst gave a one-dimensional infinite chain metal organic framework (MOF) (<b>1</b>) with the formulation {[(<i>cis</i>-(2C-2C)bi-TPHPI)<sub>2</sub>(<i>trans</i>-(2C-2C)Bi-TPHPI)](Cu<sub>2</sub>Br<sub>2</sub>)(Cu<sub>4</sub>Br<sub>4</sub>)}<sub><i>n</i></sub>. The (2C-2C)bi-TPHPI ligand formed in situ was shown to be present as both the cis and trans C(2)−C(2) coupling isomers, which was confirmed by LC-MS analysis revealing two peaks at 19.96 and 21.65 min containing a peak at 503 Da assignable to the [M + H]<sup>+</sup> molecular ion fragment. To our knowledge, the trapping and structural characterization of such intermediates through formation of MOF complexes is unprecedented.