Flash Communication: Sulfonyl Fluoride Activation via S-F and C-S Bond Cleavage by a Ni(0) Bis-Bidentate
Ethan B Chavarin1, Zoe Y Marr1, Jacob P Brannon1
1Chemistry & Biochemistry Department, California State Polytechnic University, Pomona, California 91768, United States.
Abstract:
This work investigates possible mechanisms and intermediates in the reactivity of p-toluenesulfonyl fluoride with a new bidentate N-heterocyclic carbene (NHC) nickel complex, (MesNHC2 oXy)-Ni-(COD) (Mes = 2,4,6-trimethylphenyl, oXy = ortho-xylyl, COD = cyclooctadiene). (MesNHC2 oXy)-Ni-(COD) was synthesized from the corresponding bis-(imidazolium) salt precursor, [MesNHC2 oXy]-[Br]2, and both were structurally characterized. (MesNHC2 oXy)-Ni-(COD) reacts with 1 equiv of p-toluenesulfonyl fluoride to furnish (MesNHC2 oXy)-Ni-(η2-SO2), HF, and 1/2 equiv of 4,4'-dimethylbiphenyl. (MesNHC2 oXy)-Ni-(η2-SO2) was structurally characterized and has a unique side-on SO2 coordination mode with a Ni-S-O angle of 60.49(5)°. DFT calculations of (MesNHC2 oXy)-Ni-(η2-SO2) are consistent with a Ni-(II) center and an activated SO2 fragment. DFT calculations also support an initial oxidative addition at either the S-F or S-C position, which have similar energetics.
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