Synthesis and characterization of disubstituted arylcyanoximes and their several metal complexes
A series of new disubstituted halogenated arylcyanoximes was synthesized using nitrosation reaction of the respective phenylacetonitriles by CH3-ONO at room temperature in isopropanol. Six synthesized colorless arylcyanoximes containing two F and/or Cl atoms at 2-, 4-, 5- and 6-positions were characterized by means of NMR, IR, UV-Vis spectroscopy and pKa studies. Crystal structures were determined for four cyanoximes and revealed the presence of only the syn-isomers for fluorinated compounds in a solid state, while the chlorinated arylcyanoxime exists as anti-isomer in the crystal. However, five out of the six protonated arylcyanoximes HL exist as a mixture of syn- and anti-isomers in solutions. Deprotonation of HL with NaOC2H5 in ether solutions leads to yellow NaL which were used as precursors for the synthesis of a series of monovalent Ag, Tl and bivalent Pd, Pt complexes. Seven palladium and platinum arylcyanoximates of [M(HL)2Cl2] composition were synthesized and characterized. Obtained colored compounds are non-electrolytes in solution. However, in EtOH and DMSO solutions Pt(II) cyanoximates undergo two consecutive solvolysis reactions. First order rate constants were measured at 294 K for complexes in both solvents. Binding modes of the cyanoxime ligands and the possible solid state structures of the obtained coordination compounds are suggested on a basis of their IR spectra and MM-2 calculations. Because of their structural resemblance to the cisplatin family of anticancer drugs, synthesized Pd/Pt arylcyanoximates were tested in vitro against human colon carcinoma WiDr cell line using cis-[Pt(NH3)2Cl2] as positive control. Results showed that two Pd(II) and Pt(II) cyanoximates containing oximino(2,4-dichlorophenyl)acetonitrile exhibit cytotoxicity at 0.25 mM concentrations.
Cyanoximes, IR-, NMR, UV-Vis spectroscopy, Palladium(II), Platinum(II), Silver(I), Thallium(I), X-ray analysis
Gerasimchuk, Nikolay, Leon Goeden, Paul Durham, Charles Barnes, John F. Cannon, Svitlana Silchenko, and Ismael Hidalgo. "Synthesis and characterization of disubstituted arylcyanoximes and their several metal complexes." Inorganica Chimica Acta 361, no. 7 (2008): 1983-2001.
Inorganica Chimica Acta