A. Shokrollahi | Yasouj University (original) (raw)

Papers by A. Shokrollahi

Research paper thumbnail of Cloud point extraction for the determination of copper in environmental samples by flame atomic absorption spectrometry

Química Nova, 2008

A simple cloud point extraction procedure is presented for the preconcentration of copper in vari... more A simple cloud point extraction procedure is presented for the preconcentration of copper in various samples. After complexation by 4-hydroxy-2-mercapto-6-propylpyrimidine (PTU), copper ions are quantitatively extracted into the phase rich in Triton X-114 after centrifugation. Methanol acidified with 0.5 mol L-1 HNO 3 was added to the surfactant-rich phase prior to its analysis by flame atomic absorption spectrometry (FAAS). Analytical parameters including concentrations for PTU, Triton X-114 and HNO 3 , bath temperature, centrifugation rate and time were optimized. The influences of the matrix ions on the recoveries of copper ions were investigated. The detection limits (3SD b /m, n=4) of 1.6 ng mL-1 along with enrichment factors of 30 for Cu were achieved. The proposed procedure was applied to the analysis of environmental samples.

Research paper thumbnail of Three new supramolecular compounds of copper (II), cobalt (II) and zirconium (IV) with pyridine-2,6-dicarboxylate and 3,4-diaminopyridine: Solid and solution states studies

Polyhedron, 2012

Three new Cu(II), Co(II) and Zr(IV) compounds, [Cu(pydcH)(pydcH 2 )]ÁOH À Á2H 2 O (1), (dapH 2 )[... more Three new Cu(II), Co(II) and Zr(IV) compounds, [Cu(pydcH)(pydcH 2 )]ÁOH À Á2H 2 O (1), (dapH 2 )[Co (pydc) 2 ]ÁpydcH 2 Á4H 2 O (2) and (dapH) 2 [Zr(pydc) 3 ]Á0.5H 2 O (3) [pydcH 2 = pyridine-2,6-dicarboxylic acid, dap = 3,4-diaminopyridine] have been synthesized and characterized by elemental analysis, spectral (IR, UV-Vis), thermal (TG/DTG/DTA) analysis, electrochemical and X-ray single crystal diffraction. Compound 1 consists of a cationic complex and in 1 the acid is coordinated to metal ion in the neutral form, which is quite rare, whereas 2 and 3 are anionic complexes with dianionic ligands. In all the compounds, the acid is coordinated to the metal center in a tridentate fashion. The coordination polyhedron in 1 and 2 is a distorted octahedron, however for 3 it is a distorted tricapped trigonal prism. These compounds are stabilized in the solid state by a complicated network of hydrogen bonds between crystallization water molecules, anionic and cationic fragments, which form 3D-supramolecular arrays. Furthermore hydrogen bonds, p-p and C-OÁ Á Áp stacking interactions seem to be effective in stabilizing the crystal structures.

Research paper thumbnail of Cloud point extraction for the determination of copper in environmental samples by flame atomic absorption spectrometry

Química Nova, 2008

A simple cloud point extraction procedure is presented for the preconcentration of copper in vari... more A simple cloud point extraction procedure is presented for the preconcentration of copper in various samples. After complexation by 4-hydroxy-2-mercapto-6-propylpyrimidine (PTU), copper ions are quantitatively extracted into the phase rich in Triton X-114 after centrifugation. Methanol acidified with 0.5 mol L-1 HNO 3 was added to the surfactant-rich phase prior to its analysis by flame atomic absorption spectrometry (FAAS). Analytical parameters including concentrations for PTU, Triton X-114 and HNO 3 , bath temperature, centrifugation rate and time were optimized. The influences of the matrix ions on the recoveries of copper ions were investigated. The detection limits (3SD b /m, n=4) of 1.6 ng mL-1 along with enrichment factors of 30 for Cu were achieved. The proposed procedure was applied to the analysis of environmental samples.

Research paper thumbnail of Three new supramolecular compounds of copper (II), cobalt (II) and zirconium (IV) with pyridine-2,6-dicarboxylate and 3,4-diaminopyridine: Solid and solution states studies

Polyhedron, 2012

Three new Cu(II), Co(II) and Zr(IV) compounds, [Cu(pydcH)(pydcH 2 )]ÁOH À Á2H 2 O (1), (dapH 2 )[... more Three new Cu(II), Co(II) and Zr(IV) compounds, [Cu(pydcH)(pydcH 2 )]ÁOH À Á2H 2 O (1), (dapH 2 )[Co (pydc) 2 ]ÁpydcH 2 Á4H 2 O (2) and (dapH) 2 [Zr(pydc) 3 ]Á0.5H 2 O (3) [pydcH 2 = pyridine-2,6-dicarboxylic acid, dap = 3,4-diaminopyridine] have been synthesized and characterized by elemental analysis, spectral (IR, UV-Vis), thermal (TG/DTG/DTA) analysis, electrochemical and X-ray single crystal diffraction. Compound 1 consists of a cationic complex and in 1 the acid is coordinated to metal ion in the neutral form, which is quite rare, whereas 2 and 3 are anionic complexes with dianionic ligands. In all the compounds, the acid is coordinated to the metal center in a tridentate fashion. The coordination polyhedron in 1 and 2 is a distorted octahedron, however for 3 it is a distorted tricapped trigonal prism. These compounds are stabilized in the solid state by a complicated network of hydrogen bonds between crystallization water molecules, anionic and cationic fragments, which form 3D-supramolecular arrays. Furthermore hydrogen bonds, p-p and C-OÁ Á Áp stacking interactions seem to be effective in stabilizing the crystal structures.