African Journal of
Pharmacy and Pharmacology

  • Abbreviation: Afr. J. Pharm. Pharmacol.
  • Language: English
  • ISSN: 1996-0816
  • DOI: 10.5897/AJPP
  • Start Year: 2007
  • Published Articles: 2252

Full Length Research Paper

Synthesis and characterization of Cu(II) and Fe(II) metal complexes of oxazepine derivative via Schiff base [Fe(HPOHBOT)Cl2] and [Cu(HPOHBOT)Cl2]

Najim abbas Jabir Al awwadi
  • Najim abbas Jabir Al awwadi
  • Thi-qar University-College of Pharmacy, Iraq.
  • Google Scholar
Bassam Abdulhussein Hasan Alsafee
  • Bassam Abdulhussein Hasan Alsafee
  • Thi-qar University-College of Pharmacy, Iraq.
  • Google Scholar
Maitham Mohamed Abdulridha
  • Maitham Mohamed Abdulridha
  • Technical institute of Shatra, Iraq.
  • Google Scholar

  •  Received: 04 August 2016
  •  Accepted: 24 August 2016
  •  Published: 22 September 2016


A Schiff base and its derivative (oxazepine) have been synthesized by the reaction between thio-semicarbazide and aromatic aldehyde 4-hydroxybenzaldehyde in ethanol in the presence of acetic acids to yield the Schiff base. This Schiff base on treatment with phthalic anhydride to give seven-member heterocyclic ring called oxazepine. Oxazepineas di-dentate ligand treated with hydrated metal chlorides CuCl2 and FeCl2 in the presence of ethanol as solvent to yield tetrahedral complexes. The structures of synthesized ligand and complexes have been established on the basis of their spectral Fourier transform infrared (FTIR), mass, 1H-NMR, elemental analysis C, H, N as well as molar conductance. The purity of the compounds was confirmed by thin layer chromatography (TLC).

Key words: Characterization, complexes, oxazepine, Schiff bases.


1,3-Oxazepine is unsaturated seven-member heterocyclic ring containing oxygen atom in position1 and nitrogen atom in position 3 in addition to the five carbon atoms (Zeid, 2013).

It is synthesized by (2+5) → 7 cycloaddition reaction of imine group (Schiff bases) as two-member component to five-member component such as maleic or phthalic, nitrophthalic and succinic anhydrides to give a seven-membered heterocyclic ring (Rahman, 2011).

Oxazepine derivatives showed a vast variety of biological activities like cancer diseases, psychotic depression (Khalid et al., 2014), mental depression associated with schizophrenia, affecting the nervous centre (CNS) (Khuluod and Hamid, 2013) used for the control of anxiety and tension states, the relief of muscle spasm and for the management of acute agitation during with drawls from alcohol (Saoud, 2011). Oxazepine derivatives showed biological activities against different types of bacteria (Abood, 2009).

The aim of this study was to synthesize new metals complexes of oxazepine derivative via Schiff base which are expected to have enhanced biological activity compared to free oxazepine (Nagham et al., 2014).


Melting points of ligand and metal complexes were taken in melting points apparatus U.k. 1H NMR spectra was recorded on a Bruker avance Mercury-300BB NMR 300 spectrometer. FT-IR spectra was obtained in KBr pallet in the 4000 to 200 cm-1 region on a Fourier transform infrared spectrophotometer Shimandzu. Mass spectra were recorded in the range of 0 to 900 m/z on a 5973 network mass selective detector. Elemental analysis C, H, and N were carried out on a Thermo finigan flash analyser, molar conductance, and molar conductance measurements were made in anhydrous DMSO at 25°C using Inolabcond 720 professional bench top meter.

Step I: Synthesis of 2-(4-hydroxybenzylidene) hydrazine carbothioamide (Schiff bases)

An equimolar amount of thiosemicarbazide (0.01 mole) and 4-hydroxybenzaldehyde (0.01 mole) was dissolved in 60 ml ethanol. The resulting mixture was refluxed for 6 h in the presence of few drops of catalytic amount of glacial acetic acid. After completion of the reaction, the mixture was poured into crushed ice; thereafter, the separated product was filtered and dried at room temperature. The product was purified by re-crystallization from ethanol, and was followed by TLC giving a yellow colour, yield percent of 81 and a melting point (m.p) of between 141 to 143°C (Rakesh et al., 2011).

Step II: Synthesis of 1-[3-(4-hydroxyphenyl)-1,5-dioxo-1,5-dihydro-2,4-benzoxazepin-4(3H)-yl]thiourea (Ligand) (HPOHBOT) .

The resulting mixture of an equimolar amount (0.02 mole) of Schiff’s bases and 0.02 mole phthalic anhydride in 25 ml of dry toluene was refluxed for 7 h. After completion of the mixture, it was allowed to cool down at room temperature. The separated product was filtered and dried at room temperature. The product was purified by re-crystallization from dioxin. The purity of the compound was followed by TLC. The physical appearance yield and melting point are shown in Table 1 (Zainab and Hasan, 2011).



Step III: Synthesis of Cu(II) and Fe (II) metal complexes of oxazepine derivative

Ligand HPOHBOT was obtained by refluxing the mixture of hydrated metal chlorides CuCl2 and FeCl2 (0.001) and (0.001) of the ligand (HPOHBOT) in 70 ml ethanol until the complexes precipitated out. The colours of the complexes were filtered, washed with water, ethanol and dried under vacuum. The purity of the compound was followed by TLC. The physical appearance yield and melting point are shown in Table 1 (Matheel et al., 2009).


The HPOHBOT ligand and their metal complexes were subjected to elemental analyses. The results of elemental analyses (C, H, N) with molecular formula and melting points are presented in Table 1. The results obtained are in good agreement with those calculated for the suggested formula. The structures of the ligand and metal complexes are also confirmed by IR, MASS, 1H NMR spectra and molar electrical conductivity which are discussed subsequently.

Infra-red spectroscopy

FTIR (KBr, cm-1) of ligand HPOHBOT showed 3483(O-H), 3409 (N-H), 3062(C-H)A, 2940(C-H)Ali, and 1639 (C= O)1482 (Abood, 2009). The band (N-H) of the complexes was shifted to a lower frequency, indicating its involvement in coordination with metal ion. These findings were further supported by the appearance of new bands at 694 to 696 and 700 to 703 cm-1 which belong to both ν(M–N) vibrations, respectively. All data tabulated in Table 1 are as shown in Figures 1 and 2 (Nagham, 2013).




1H NMR spectra data of ligand

The 1H NMR spectra of the HPOHBOT (L) in DMSO solutions with assignments are collected in Table 2 and 3. The 1H NMR spectra of the free ligand (Figure 3) showed the aromatic proton signals appearing at 7 to 8 ppm and also showed C-H proton at 8.2 ppm, secondary amine proton at 9.8 and 9.2 ppm of primary amine proton. The phenol OH proton has a signal at 10.5 ppm (Dhanya et al., 2014).





Mass spectra

Mass spectral data confirm the structure of the ligand and their Cu(II) and Fe (II) complexes as indicated by the molecular ion peaks corresponding to their molecular weight. All data are as shown in Scheme 1 and 2, tabulated in Table 4 (Figures 4, 5 and 6) (Mukhlus et al., 2012).








Molar conductance measurements

The molar conductance data of the prepared complexes solution tabulated in the Table 6 were measured at room temperature in 10-3 M DMSO solvent. All exhibited low value of molar conductivity (0 to 20) which indicates that complexes under study is non-electrolyte Table 5. The obtained value suggested that no anions (Counter Ions) present outside the coordination sphere and showed good agreement with that reported in the literature (Alya, 2015).




In the present study, Fe(II) and Cu(II) complexes with ligand HPOHBOT (L) have been synthesized and identified by IR, 1HNMR, mass spectra, elemental analyses C, H, N, and molar conductance. ν(M-N) band of ligand appeared in the prepared complexes at 694 cm-1 in Cu complex and 669 cm-1 in Fe complex and also (N-H) band of NH2 for the synthesized ligand shifted from 3361 to 3416 cm-1 in Cu complex and 3409 cm-1 in Fe complex due to the coordination with the matal. This view further support that the coordinate appeared through the nitrogen of (C-N) and N of NH2.

In all the physical and chemical measurements, it was suggested that the chemical configuration of the prepared complexes as tetrahedral geometry complexes is as shown in Scheme 3 and 4 (Selvana, 2012).




The authors have not declared any conflict of interest.


Abood ZH (2009). Synthesis of Some New 1,3-Oxazepine and Tetrazole Derivatives Containing Azo Group. J. Karbala University Scientific. 7(1):297-303.


Alya KA (2015). Lanthanide Ions Complexes of 2-(4-amino antipyrine) -L-Tryptophane (AAT). preparation, identification and antimicrobial assay. Iraqi J. Sci. 56(4C):3297-3309. ascorbic Acid. 25(2):1-7.


Dhanya S, Ranjitha C, Rama M, KSR Pai (2014). Oxazepine Derivative as an Antitumor Agent and Snail1 Inhibitor against Human Colorectal Adenocarcinoma; Inter. J. Innovative Res. Sci. Eng. Technol. 3(8):15357-15363.


Khalid M, Mohamad Al-janaby Ali I, Mustafa AL-Jobory (2014). Synthesis and Biological testing of new 1,3- oxazepine derivatives of pharmaceutical interest; Karbala J. Pharmaceut. Sci., p. 7 .


Khuluod FH, Hamid HE (2013). Synthesis, characterization, biological evaluation and anti corrosion activity of some heterocyclic compounds oxazepine derivative from schiff bases. Inter. J Chem. Tech Res. 5(6):2924-2940.


Matheel D, Al-Sabti, Ahmed AH, Al-Amiery Ysmien K, Al-Majedy Anaheed H Hameed (2009). Synthesis and characterization of some complexes of Cr (III), Co (II), Ni (II), and Cu(II) with (1-Benzoyl-1H-3-Methyl-1H Pyrazol-5 (4H) – one. J. Al-Nahrain University Science. 12(4):31-37.


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Rahman TH (2011). Synthesis and characterization of Some New Tetrazole and 1,3-Oxazepine Derivatives; J of Karbala University Scientific. 9(3).


Rakesh T, Naimish C, Manish KS (2011). Synthesis and characterization of some new thiosemicarbazide derivatives and their transition metal complexes. J. Chem. Pharm. Res. 3(2): 290-297.


Saoud SA (2011). Synthesis and Characterization of Some New 1,3-Oxazepine Derivatives; Ibn Al- Haitham J. Pure Appl. Sci. 24(1):170-177.


Selvana AY (2012). Synthesis of substituted (oxazepine, Diazepine, tetrazde) via Schiff Bases for 2- Aminobenzo Thaizole Derivatives. J.Baghdad Sci. 10(3).


Zainab AS, Hasan TG (2011). Synthesis of New 1,3-Oxazepine Derivatives Containing Azo Group. J. Kufa Chem. Sci. 2:11-23.


Zeid HA (2013). Synthesis and Characterization of Some New Bis- 1,3-Oxazepines-4,7-Dione and Bis-1,5-Disubstituted tetrazoles Linked to Benzothiazole and Thiadiazole Moieties and Containing Two Azo Groups Chemistry Department; Iraqi National J. Chem. (50): 207.