UBC Undergraduate Research

Reactivity of CpCr(III) N-Heterocyclic Carbene Diiodide Yallits, Emily


Chromium complexes are well known for their applications in alkene and alkyne trimerization. In this thesis, a previously synthesized CpCr(NHC)I2 complex (where NHC stands for N-heterocyclic carbene), were investigated for alkyne trimerization. The objective was to optimize the reduction and initial alkyne-coupling steps of the mechanism to isolate a well-defined chromacyclopentadiene complex which could later be used for synthetically applicable alkyne trimerization. Initial attempts to utilize the complex to couple two alkyne substrates appeared promising; however, obstacles in spectral analysis prevented any conclusive characterization of the desired complex. The possibility of bimolecular decomposition with similar complexes reported by Jolly6a led to the synthesis of a novel CpCr(iPr-NHC)Cl with bulkier isopropyl substituents on the NHC ancillary ligand. Applications of CpCr(iPr-NHC)Cl in alkyne trimerization appear to be very promising as the isopropyl substituent likely prevents decomposition and improves the crystalline structure of the compound which is helpful for characterization. A number of other CpCr(L)X2 compounds were also tested for reactivity in alkyne trimerization which illustrated the significance of ancillary ligand electron-donating abilities in this type of reactivity.

Item Media

Item Citations and Data


Attribution-NonCommercial-NoDerivatives 4.0 International