Effect of variation of the halides on the proton isotropic shifts of triphenylphosphine in trihalogeno-(triphenylphosphine)cobaltate(II) anion

Abstract

The effect of X (Cl^–, Br^– and I^–) on the proton isotropic shifts of the triphenylphosphine protons in the complex anion [CoX₃(PPh₃)]^– has been studied. The magnitude of the proton isotropic shifts of the meta-¹H and para-¹H increases from Cl^– to I^– in all the solvents studied, but the reverse is true for the ortho-¹H. Ion-induced magnetic anisotropy accounts for the reversed trend.