ESR Spectra of halo[1, 1, 1-tris(deiphenylphosphinomethyl)ethane] nickel(I) complexes

The single crystal ESR spectra of halo[1, 1, 1-tris(diphenylphosphinomethyl) ethane]nickel(I), Nip3X (X = Cl, Br, I) are reported. Due to short spin lattice relaxation the spetcra were recorded at 4.2 K. Completely anisotropic g calues were obtained for the chloride and the bromide doped into the corresponding copper(I) complex, and for the magnetically undiluted iodide. The hyperfine splitting due to two equivalend phospurus atoms was resolved. Single crystal polarized electronic spectra of Nip3I were recorded in order to gather information on the energies of the electronic levels. Attempts were made to calculate the g values through a ligand field model. An orbitally degenerate ground level is anticipated, which might be responsibel for the unusual features of the specrtra.