Synthesis, characterization, and the role of counterion in cyclopropanation of styrene catalyzed by [CuI(2,2′-bpy)(π-CH2CHC6H5)][A] (A=ClO4-,PF6-andCF3SO3-) complexes

Copper(I)/2,2′-bipyridine complexes, [CuI(bpy)(π-CH2CHC6H5)][A] (A=CF3SO3-(1),PF6-(2)) have been synthesized and characterized. The equilibrium constants for the coordination of styrene to [CuI(bpy)]+ cations at 300 K were determined to be 4.3 × 103 (1), 4.4 × 103 (2) and 3.8 × 103 M−1(A=ClO4-,3). These data suggested that the axial coordination of the counterion in these complexes observed in the solid state (2.4297(11) Å 1, 2.9846(12) Å 2, and 2.591(4) Å 3) did not significantly affect the binding constant of styrene to [CuI(bpy)]+ cations in solution. In cyclopropanation reactions catalyzed by 1–3, similar product distribution was obtained. The rate of decomposition of EDA in the presence of styrene at room temperature catalyzed by 3 (kobs = (7.7 ± 0.32) × 10−3 min−1) was slower than the rate observed for 1 (kobs = (1.4 ± 0.041) × 10−2 min−1) or 2 (kobs = (1.0 ± 0.025) × 10−2 min−1).

Graphical abstractSynthesis, characterization, and the role of counterion in cyclopropanation of styrene catalyzed by [CuI(2,2′-bpy)][(π-CH2CHC6H5)][A] (A=CF3SO3-,PF6-andClO4-,) are described.Figure optionsDownload full-size imageDownload as PowerPoint slide