Six complexes of di-and tri-(2-pyridyl)amine have been prepared for pairs of metal isotopes (63Cu, 65Cu; %Fe, 57Fe). When the electronic ground state of the metal-tri-(2-pyridyl)amine complex ion is non-degenerate and the microsymmetry of the metal l&and array approximates closely to Oh only one mode is metal sensitive (e.g. [Fe(II)(tripyam)z] (ClO&). However, for [Cu-(II)(tripyam)J (PF& the observation of two metal sensitive modes indicates a lower effective symmetry, which is reasoned to arise from a "tetragonal"distortion of the CuNe array. The isomeric [Cu(II)(tripyam)2(C104)z], with bidentate ligands, gives shift data consistent with a transdiperchlorato~omplex. The structure of [Cu(II)(dipyam)a] (ClO& is known and the shift data are in good accord with expectation. The trigonal bipyramidal structure previously proposed for [Cu(II)(dipyam)zClj Cl is completely supported, but the structure of [Cu(II)-(dipyam)2(N03),] appears less regular than formerly believed. All metal-nitrogen stretching frequencies are located below 300 cm-' with the exception of the low spin bis-tri-(2-pyridyl)amineiron(II) perchlorate for which v,, (FeN) = 307 cm-', a value in good agreement with proposed for low spin bis-tri-(2-pyridyl)aminecobalt
using a different experimental approach to the assignment.