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Journal of the Chilean Chemical Society

versão On-line ISSN 0717-9707

J. Chil. Chem. Soc. v.54 n.2 Concepción jun. 2009 

J. Chil. Chem. Soc, 54, N° 2 (2009)






Selçuk University, Faculty of Arts and Sciences, Department of Chemistry, 42075 Konya, Turkey. e-mail:


In this study, anti-1-acetyl-l-cyclohexenylchloroglyoxime (C8HUC1N2O2) has been synthesized by chlorination of anti-1-acetyl-1-cyclohexeneglyoxime. As a result of the reaction of C8HnC1N2O2with aryl- or arylalkylamines in ethanol between -10 °C and -15 °C , unsymmetrical vic-dioximes were obtained and the obtained products were named as: anilino-1-acetyl-1-cyclohexeneglyoxime (C14H17N3O2), benzylamino -1-acetyl-1-cyclohexeneglyoxime (C15H19N3O2), p-toluidino -1-acetyl-1-cyclohexeneglyoxime (C15H19N3O2) respectively. Their transition metal complexes have been synthesized. The form of the obtained Ni(II) and Cu(II) complexes were found as square-planer as it is known usually. 'H n.m.r, conductivity measurements, magnetic properties, i.r spectra and elemental analyses data of ligands and complexes are given. In addition to this, thermal characterizations of the ligands and their complexes have been investigated.

Key Words: Copper(II), Ligands, Nickel(II), Oximes, v1c-dioximes.



Vic-dioximes have received considerable attention as model compounds which mimic bifunctions such as the reduction of B1212. Oxime metal chelates are biologically active3 and are reported to possess semiconduction properties4,5. Derivates of some momoaminoglyoxime, vic-dioximes, tetraoximes and their transition metal complexes have been described2,6-16.

Nowadays, vic-dioximes are appreciated as coordination compounds in lots of usage areas such as analytical, biologically, pigment and medicinal chemistry. Many researchers have studied vic-dioximes, and the important role of the complexes especially 1,2-dioximes in coordination chemistry4,5. The substitution pattern of v/c-dioxime moiety affects the structure and stability of the complexes4-8, but the complexes are decomposed in the case of aminogl-yoxime derivates17. In the present paper, I report the synthesis of and complex formation by two new substituted amino-1-acetyl-1-cyclohexeneglyoximes as examples of unsymmetrically substituted v¿c-dioximes. The unssymmetry of the ligands is also expected to enhance the solubility of planar complexes derived from them.



Materials and methods

1-acetyl-1-cyclohexene was bought ready-made from Merck. Anti-1-acetyl-1-cyclohexeneglyoxime was prepared by reported procedures13,17-19. M.p.s.'s were measured on an Electrothermal IA 9100 digital melting point apparatus. Elemental analyses (C, H and H) were realized using a Carlo-Erba 1106 model analyzer. 1H-n.m.r. and i.r. spectras were obtained with Bruker 200 MHz spectrometer and Jasco FT/I.r-300 instrument, respectively. The pH of the solutions were adjusted and controlled with WTW pH.537 pH meter. Molar conductance of the ligands and their metal complexes were determined at room temperature using a CMD 750 WPA conductivity meter. TGA curves were recorded on a Shimadzu TG-50 thermo balance.


Anti-1 -acetyl- 1-cyclohexenechloroglyoximes, anti-C8 h11CIN2O2

Dry chloro gas was passed through a suspension of anti-1-acetyl-l-cy-clohexeneglyoxime (3.36 g, 0.020 mol) in 30 niL chloroform under sun light for 1/2 h until the color of suspended material became grey. After the transition of Cl2 for 2 h under UV-irradiation (254 run), it was observed that the temperature of the mixture reached 35 °C and crystals formed. The mixture was cooled to room temperature, excess Cl2 was expelled in vacuum and then the solution was filtered and the solid was washed with chloroform and then water. By the recrystalization in ethanol-water (1:2) 3.95 g (%78) product was gained with m.p. as 130 °C.

It was determined that this obtained compound was soluble in ethanol, DMSO, DMF and diethyl ether but insoluble in water.

Synthesis of Substituted Amino-1-acetyl-1-cyclohexeneglyoximes [L1H2], [L2H2] and [L3H2J

The solution of 0.01 mol freshly distilled amino compounds such as [aniline (2 niL), benzylamine (2.2 mL), p-toluidine (1.07 g) ] in absolute ethanol (30 mL) was added to a stirred of anti-C8HnClN202 (2.025 g, 0.01 mol) in absolute ethanol (35 mL) between -10 °C and -15 °C drop by drop in 30 min. The reaction mixture was further stirred for 2 h and then diluted with water to 120 mL and left overnight at 5 °C. The precipitate was filtered and then recrys-tallized from ethanol-water (1:2). The crysalline product was filtered, washed with water and dried at room temperature.

Synthesis of the Ni(II) and Cu(II) Complexes

When a solution of 0.6 mmol metal salt [ NiCl2 6H20 (0.143 g), CuCl2 2H20 (0.103 g)] in 25 mL absolute ethanol was added into a solution of the ligand (1.2 mmol) [C14H17N302 (0.311 g), C15H19N302 (0.328 g), C15H19N302 (0.328 g)] dissolved in 25 mL of ethanol, the pH of the mixture changed as 3.0-3.5 and its color turned to red-brown. In order to raise the pH to 4.5, 1% NaOH solution in ethanol was added and the mixture was stirred in a water bath at 50-55 °C for 15 min. The precipitated complexes were filtered while they were hot, washed with water, ethanol and diethyl ether and dried at 100 °C. The colors, yields and melting point of the compounds are given in table 1.


In this study, starting with methylcyclohexylketone( 1-acetyl-l-cyclohexene), anti-1-acetvl-1-cvclohexenvlglvoxime was carried first by oxidation of the methyl group to the isonitroso group and, subsequently, conversion of C = O to the oxime by condensation with hydroxylammonium chloride, as given in the literature18. Chlorination of this compound in chloroform afforded anti-1-acetyl-1-cyclohexenylchloroglyoxime (C8HUC1N202), an acceptable starting material to obtain various unsymmetrically substituted 1-acetyl-1 cyclohexenylglyoxime (Figure 1).





The reaction of C8HnC1N202 with three different arylamines inethanol at-15 °C gave three new substituted amino-1-acetyl-1-cyclohexenylglyoximes (Figure 2)

In the 1H-n.m.r. spectra, two different -OH peaks were seen for these ligands (Table 1). These two deuterium exchangeable singlets correspond to two non equivalent structures which indicate the anti-configuration such as cis -and trans - form of this compound17,19-20. The chemical shift of the O-H protons is seen at 11.90-12.05 ppm and the N-H protons at 6.96-8.65 ppm. The losing of these peaks with the addition of D2O to the solution guides that the observed chemical shifts belong to the protons of O-H and N-H groups. 1H-n.m.r. for L2H2 : 6.96ppm (N-H, 1H), 4.25 ppm, CH2, 2H).

1H-n.m.r. spectra of the complexes

The solubility of the complexes of the three new unsymmetrical ligands is not enough to obtain 1H-n.m.r. spectra in solution except [Ni(HL2)2J. The proton n.m.r. spectrum of this diamagnetic complex indicates the formation of O - H...H bridge by the strong shift of the peak of complex at 14.15 ppm and this obtained data were contrary to the L1 H210,20. These values were given as 4.30 ppm (-CH2, 4H). for Ni(II)complex. In conclusion of the unsymmetry in the ligands, the complexes are accepted to form two isomers (Fig 2). TLC (sili-cagel-G) was employed with different solvent mixtures and varying polarities, but only one spot appears in each case. This result implies that the formation of only one isomer is possible under these reaction conditions. The geometric iso-merism of [Ni(HL1)2] can be inferred from the 1H-n.m.r. spectrum, since the alternative chemical environments will show two O — H - O bridge protons in the cis-form, but only one of them is in the trans-structure. The observed spectrum has only one resonance at 14.15 ppm implying the trans-form of complex.

Magnetic properties

Magnetic susceptibility measurement provides information to characterize the structure as shown in Table 2. The mononuclear Ni(II) complexes of these ligands are diamagnetic as expected for a d8 metal ion in a square planer field20,21. The Cu(II) complexes at 20 °C are paramagnetic, Heff= 1.20 - 1.44 BM.

Conductivity measurements

The molar conductance values of the synthesized ligands and their Ni(II) and Cu(II) complexes were measured and by the way it was seen that all the complexes are non-electrolytes.

I. r. spectra of ligands and complex

In the i.r. spectra of the ligands, -NH (3370-3420 cm1), OH (320-3110 cm1), C=N ( 1680-1610 cm1) and NO (980-960 cm1) stretches appear at frequencies expected for substituted glyoxime12,18,21 (Table 3). The characteristic i.r. absorptions of the complexes are given in Table 3. The range of the metal-ligand 1:2. From the results it can be said that Ni(II) and Cu(II) compounds were square-planar coordination as it is seen from Figure 2.. The i.r. spectra of the complexes support these structures by weak bending vibration of the O-H O bridges around 1640-1720 cm-1 and the shift of the C=N vibration to lower frequencies at 1600 -1630 cm-1 due to N,N-metal coordination12,22.

TGA Analysis of metal complexes

The TGA curves for the Ni(II) and Cu(II) complexes were obtained at a heating rate of 10 °C / min in a nitrogen atmosphere between the temperature range of 362-1086 °C. It was seen from the TGA results that decomposition of Ni(II) and Cu(II) complexes began between 362-441 °C and finished between 728-1086 °C. Ni(II) and Cu(II) complexes decompose to NiO and CuO in 3 steps in the temperature ranges. These results showed similarity with the results of other literatures23-26.



The authors are greatefull for the kind financial support provided by Sel-cuk University Research Foundation (SUAF).



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(Received: March 10, 2008 - Accepted: January 28, 2009)

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