Acetyl hydrazone oxime, [(1E,26)-2-(hydroxyimino)-1-phenylethylidene]acetohydrazone (hipeahH(2)) and its palladium(II) and platinum(II) complexes, [M(hipeahH)(2)] (M = Pd-II and Pt-II), have been synthesized and characterized by elemental analysis, UV-vis IR, NMR and LC-MS techniques. X-ray diffraction analysis of [Pd(hipeahH)(2)] shows that the two hipeahH(2) ligands are not equal; one of the ligands loses the hydrazone proton, while the other one loses the oxime proton, resulting in a different coordination behavior to form five- and six-membered chelate rings. The molecular geometries from X-ray experiments in the ground state were compared using the density functional theory (DFT) with the B3LYP method combined with the 6-311++G(d,p) basis set for the ligand and the LanL2DZ basis set for the complexes. Comprehensive theoretical and experimental structural studies on the molecule have been carried out by FT-IR, NMR and UV-vis spectrometry. In addition, the isomer studies of ligand and its complexes were made by DFT. (C) 2015 Elsevier B.V. All rights reserved.