ORIGINAL RESEARCH Theoretical study of hydrolysis of an imine oxime in aqueous solution and crystal structure and spectroscopic characterization of a platinum(II) complex containing the hydrolysis product Yunus Kaya • Veysel T. Yilmaz Received: 18 February 2013 / Accepted: 9 April 2013 Ó Springer Science+Business Media New York 2013 Abstract The hydrolysis of an imine oxime (ppeieoH) in neutral and acidic aqueous solutions was studied using DFT at the B3LYP/6-311G(d,p) level. The rate-determin- ing step at the neutral and acidic aqueous solutions is the nucleophilic attack of the water molecules to the neutral or protonated imine C atom of ppeieoH. The activation energy is much lower in the acidic hydrolysis. The hydrolysis of ppeieoH results in the parent carbonyl oxime (inapH) and amine compounds with DG cal values of 8.66 and 11.02 kJ mol -1 in the neutral and acidic solutions, respectively. The hydrolysis of ppeieoH was observed experimentally during its reaction with K 2 [PtCl 4 ] in an aqueous solution. The reaction yielded [PtCl(i- nap)(DMSO)], which contains only the hydrolysis product inap. The new platinum(II) complex was characterized spectroscopic techniques and X-ray diffraction. The plati- num(II) ion is coordinated by chlorido, carbonyl oxime (inap), and DMSO ligands forming a distorted square- planar arrangement. The molecules of the platinum(II) complex were connected by weak non-conventional C–HÁÁÁO and C–HÁÁÁp hydrogen bonds. Keywords Hydrolysis of imine oxime Á DFT/B3LYP calculations Á Carbonyl oxime Á Platinum(II) complex Á Crystal structure Introduction The chemistry of transition metal complexes of oximes has been investigated extensively [1–7]. The oxime group can function as monodentate (N or O), bidentate chelating (N, O), and bridging (N, O) ligand [7–12]. Although oximes and their metal complexes have received great attention, there have been few reports concerning their hydrolysis. For example, the hydrolysis of benzophenone oxime was reported in 1934 [13]. Depuy and Ponder [14] reported that the hydrolysis of various oximes in the presence of levu- linic acid produced the corresponding carbonyl com- pounds. The hydrolysis of O-(methylcarbamoyl)oximes in basic solutions was studied by Mrlina and Calmon [15]. In some cases, the conversion of oximes into their parent carbonyl compounds was achieved by the metal ion- assisted hydrolysis using CuSO 4 Á5H 2 O[16], SnCl 2 /TiCl 3 [17] and cerium(IV) [18]. Moreover, it has been theoreti- cally proposed that the hydrolysis of cyclohexanone-oxime in subcritical and supercritical water leads to the formation of cyclohexanone and e-caprolactam, respectively [19]. Recently, we synthesized an imine oxime, namely (1E,2E)-phenyl-[(1-phenylethyl)imino]-ethanal oxime (ppeieoH) [20]. During the preparation of the palladium(II) complex of ppeieoH, we observed that the partial hydrolysis of the imine oxime ligand occurs during complexation in the presence of water, resulting in the corresponding car- bonyl oxime and amine [21]. The hydrolysis of the imine bond (C=N) in this oxime compound directed us to study its mechanism theoretically using density functional theory (DFT). In addition, a platinum(II) complex containing the hydrolysis product of the imine oxime ligand was isolated and crystallized. This paper reports the theoretical study of the hydrolysis mechanism of ppeieoH to produce isonitr- osoacetophenone (inapH) and 1-phenylethaneamine in Electronic supplementary material The online version of this article (doi:10.1007/s11224-013-0273-6) contains supplementary material, which is available to authorized users. Y. Kaya Á V. T. Yilmaz (&) Department of Chemistry, Faculty of Arts and Sciences, Uludag University, 16059 Bursa, Turkey e-mail: vtyilmaz@uludag.edu.tr 123 Struct Chem DOI 10.1007/s11224-013-0273-6