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The nitrile complex [Ph3PCH2Ph][PtCl5(EtCN)] reacts with one equivalent of salicylaldoxime, HONCH(C6H4OH-o), in CH2Cl2 to afford mainly the addition product [Ph3PCH2Ph][PtCl5{NHC(Et)ONCH(C6H4OH-o)}] (1). In a diluted solution, i.e. if the same amount of the reagents is dissolved in 50-fold volume of dichloromethane, the four platinum-containing species, i.e. 1, [Ph3PCH2Ph][PtCl4{C6H4(O)C(H)NOH}] (2) [Ph3PCH2Ph][PtCl5(NH3)] (3), and [Ph3PCH2Ph]2[PtCl6] (4), are formed and the substitution compound 2 is the major product at low concentrations. Addition of EtCN to the less concentrated solution suppresses the formation of the substitution product 2 and moves the reaction back towards formation of the addition product 1. The complex 1 is unstable in non-dried solutions and decomposes to give 2 along with 3, 4 and EtCO2H. Compounds 1, 2 and 4·1/2H2O were characterized by elemental analyses, FAB mass-spectrometry, IR and 1H, 13C{1H}, 31P{1H} and 195Pt NMR spectroscopies. X-ray structure determinations have been performed for 2 and 4·1/2H2O.

The reaction of [ReOCl3(PPh3)2] with salicylaldoxime unexpectedly yields [ReCl4(OPPh3)2] (1) and [ReOCl2(PPh3)(η2-OC6H4-2-CHNH)] (2). The crystal structure of the Re(IV) complex 1 consists of discrete mononuclear units. The Re site is bound to four chlorides and two trans oxygens of the OPPh3 groups. The crystal structure of 2 is also mononuclear with the geometry of the Re(V) center defined by a terminal oxo-group, two cis chlorides, the phosphorus of the PPh3, and the nitrogen and oxygen donors of the phenoxyimino ligand [OC6H4-2-CHNH]−.

Reaction of K[PtCl3(Me2SO)] and salicylaldoxime gives trans-(S,N)-[PtCl2(o-HOC6H4CHNOH)(Me2SO)]·H2O, which contains the oxime coordinated in the unusual ligand monodentate fashion. In the presence of one equivalent KOH the reaction leads to a mixture of cis-(S,N)- and trans-(S,N)-[PtCl(o-OC6H4CHNOH)(Me2SO)]; the structure of the cis-(S,N)-isomer was determined by X-ray crystallography. On incubation the mixture of the isomers in chloroform or dichloromethane solutions at 20–25°C for 8 weeks, the geometrical cis → trans isomerization takes place, giving exclusively trans-(S,N)-isomer. Chlorination of both trans-(S,N)-[PtCl2(o-HOC6H4CHNOH)(Me2SO)]·H2O and trans-(S,N)-[PtCl(o-OC6H4CHNOH)(Me2SO)] with excess Cl2 results in oxidation of Pt(II) and instead of the Piloty reaction or oxidative deoximation, chlorination in para and ortho positions of the benzene ring giving, as a result of the overall process, the platinum(IV) complex trans-(S,N)-[PtCl3{Cl2(O)C6H2CHNOH}(Me2SO)] which was characterized by X-ray crystallography.

Cyclic voltammetry at a micro electrode of Co(II) salen, Fe(II) salen, electrode generated Fe(II)(acac)2, Fe(II) (salicylaldehyde)2, Fe(II) (salicylaldoxime)2, Fe(II) (bipy)3, Fe(II) (bipy)2, Co(II) (bipy)3, Co(II) (benzacac)2, and electrode generated Co(acac)2 in oxygen saturated aprotic solvents show positive shift of the O2 sigmoidal wave, as well as enhancement of the limiting current in the case of the first five compounds. In the case of Co(II) (bipy)3 the slope of the sigmoidal wave due to O2 becomes more positive, while for the other two Co(II) complexes there is no change except a small decrease in the wave height. The data are used to correlate and predict the O2 binding properties of the chelates in solution. The data for the diketone complexes of Co(II) indicate absence of any direct association, which is in line with the interpretation offered in the literature on the mechanism of their catalytic role in the O2 oxidation of substrates. The mechanism of the autoxidation of dimethylformamide in the presence of Fe(III) (bipy)3 and Cu(II) (bipy)2 is elucidated by the observation that these higher valent compounds are reduced to their next lower oxidation state by DMF.

The antineoplastic, antiproliferative and other biological properties of the copper(II) chelates of salicylaldoxime and related ligands are reviewed. Original results are reported on the toxicity and some other properties of the compounds, and possible mechanisms of action are discussed.

ESCA investigations of transition metal complexes of salicylaldoxime and its derivatives were used to demonstrate how the electron binding energies of the donor atoms and central atoms are affected by complex formation, by the stabilities of the resulting complexes, by substituents changing the electron densities of the donor atoms, and by cis-trans isomerism. A qualitative correlation was revealed between the ESCA data and the individual vibrational bands of the complexes, and also the bands of their electronic excitation spectra.

The acute toxicity of the recently discovered antiproliferative and antineoplastic agent trans-bis- (salicylaldoximato)copper(II) (CuSAO2) has been studied in Wistar rats. When given perorally as a suspension, the compound had no acute lethal toxicity even at the dose of 5000 mg per kg body weight. The peroral LD50 value (in rats) of the corresponding free ligand, salicylaldoxime, is known to be only 400 mg/kg. The decreased toxicity of CuSAO2, as compared to the free ligand, may at least in part be due to its lack of absorption. CuSAO2 was found to be absorbed poorly, if at all, when given perorally. When CuSAO2 was given intraperitoneally to Wistar rats, its absorption was found to be incomplete, and therefore no attempt was made to determine its intraperitoneal LD50 value.