Bite-Angle-Regulated Coordination Geometries: Tetrahedraland Trigonal Bipyramidal in Ni(II) with Biphenyl-Appended (2-Pyridyl)alkylamine NN′-Bidentate Ligands

摘要

Two simple biphenyl-appended (2-pyridyl)alkylamine N-bidentate ligands, L^e and L^m, having ethylene and methylene spacers between donor groups, with bite angles L^e ≈ 100° and L^m ≈ 80°, dictate pseudotetrahedral and trigonal-bipyramidal geometries in six high-spin Ni(II)-halide complexes, [Ni(L^e)X2] and [Ni(L^m)2X](ClO4) (where X = Cl^–, Br^–, I^–), respectively. The structures in the solid state, determined using X-ray crystallography, and in solution, determined using spectroscopic methods (UV–vis–NIR and paramagnetic ¹H NMR), which complement each other, are described.