Arslan H. | Küçük Y. | Menteş A. | Acar M.H.

Makale | 2013 | Turkish Journal of Chemistry37 ( 5 ) , pp.824 - 831

Atom transfer radical polymerization (ATRP) of styrene was carried out with multidentate nitrogenbased ligands, namely N,N'-bis[phenyl(pyrid-2-yl) methylene] ethane-1,2-diamine (BPDA) and N,N'-bis[methyl(pyrid- 2-yl)methylene] ethane-1,2-diamine (BMDA), and catalyst systems at catalyst/ligand molar ratios of 1/0.33, 1/0.5, 1/1, and 1/1.5 by using 2 different initiators, (1-bromoethyl)benzene (BEB) and ethyl-2-bromopropionate (EBP). Linear first-order kinetic plots were observed for ATRP of styrene upon using BPDA as a ligand with both initiators. Even though the linear slopes indicate that radical concentration remains constant duri . . .ng reactions, high molecular weights were obtained at low conversion and showed a linear relation thereafter. To investigate the molecular weight effect, reactions were also performed in the presence of (1-bromoethyl)benzene initiator in dimethylformamide (DMF) for BPDA and in toluene for BMDA using a catalyst/ligand ratio of 1/1.© TÜBITAK Daha fazlası Daha az

Baran Y. | Baran S. | Tunali N.K.

Makale | 1997 | Turkish Journal of Chemistry21 ( 2 ) , pp.105 - 110

The syntheses, pKa and spectrospcopic characterization of [Fe(CN)5(H2O)]-3 and [Ru(CN)5(H2O)]-3 complexes of alanine(Ala), glycine(Gly), valine(Val), lysine(Lys), arginine(Arg) and cysteine(Cys) complexes were investigated in aqueous solution. The spectra of the complexes containing amino acid ligands were similar to that of [Fe(CN)5(NH3)]-3. The pKa values of the complexes were measured by spectrophotometric titration at 22°C and µ = 0.100 M(NaClO4).

Baran Y. | Erk B.

Makale | 1996 | Turkish Journal of Chemistry20 ( 4 ) , pp.312 - 317

The synthesis and characterization of Sn(II) and Sn(IV) complexes of nitrogen and oxygen ligands, p-dimethyl aminophenylenesalicyladimine (DPS), N,N'phenylenebis(salicylaldimine)(PBS) and N, N'-triethylenetetramine bis (salicylaldimine)(TTS) are reported. The structure of free ligands and their tin complexes were determined by elemental analysis, ir and nmr measurements. The kinetics of formation of the complexes were studied by stopped-flow technique at several temperatures with µ=0.100 M (NaClO4). Activation parameters ?H* and ?S* were determined.

Sengul A. | Agaç H. | Çoban B. | Eroglu E.

Makale | 2011 | Turkish Journal of Chemistry35 ( 1 ) , pp.25 - 36

The tetradentate ligand 6,6'-diacetyl-2,2'-bipyridine dioxime (L) was obtained in high yield by the condensation reaction of 6,6'-diacetyl-2,2'- bipyridine with hydroxyl amine in alkaline solution. Density functional calculations and 3D modeling of the structure at the B3LYP/6-31G(d) level of theory for L revealed that the energy difference between the global trans conformer (trans-L), which possesses the C2h point group, and the distorted cis conformer (cis-L) was 5.214 kcal/mol. Synthesis and characterization of the metal complexes with Cu(I), Cu(II), Pt(II), and Pd(II) metal ions were reported. L acted as a N4- donor ligand to co . . .ordinate to the metal centers via N atoms of the 2,2'-bipyridine and the imine moieties to afford tetrahedral complex [CuI L]PF6 (1), distorted octahedral complex [CuII L(OH2)2](NO 3)2 (2), and square-planar complexes [PtII L]Cl2 (3) and [PdII L]Cl (4), respectively. The CHN analysis for 1 implies that L coordinated to 2 copper(I) ions as a bridging ligand to form a dinuclear metal complex, [Cu2L2] 2+, due to the twisting of the coordinated bonds exposed by the tetrahedral geometry preference for the metal ion. The ligand formed intramolecular hydrogen bonds between the oxime groups in 4, as revealed by the spectroscopic studies. The most stable conformations of the compounds were obtained by using the molecular mechanics optimization feature in CAChe software with an augmented MM2 force field. 1. © 2011 Tübïtak Daha fazlası Daha az

Agaç C. | Yilmaz I. | Şengül A. | Coles S.J.

Makale | 2010 | Turkish Journal of Chemistry34 ( 5 ) , pp.781 - 791

The single crystal X-ray structure of the novel multimodal ligand 6, 6'-bis(2-(di(pyridin-2-yl)methylene)- 1-methylhydrazinyl)-2, 2'-bipyridine, C34 H28N10 (L), was determined at 120 (2) K. The ligand possesses a centre of symmetry that generates a planar bipyridyl core with the hydrazone substituents in a trans- geometry. The di-2-pyridyl moieties at either terminus of the molecule twist out of the plane (52.90 and 56.32 A). The crystal structure comprises 2-dimensional ribbons that stack about each other so as to optimise van der Waals interactions and packing efficiency. Studies of the coordination properties of the novel multimo . . .dal ligand with copper(I) show that 2 ligand strands wrapped around the copper(I) having a preference for tetrahedral geometry to furnish a supramolecular self-assembled of a double-stranded tri-nuclear helical complex, {[Cu3L 2](PF6)3-3H2O} (1), as revealed by the ESI-MS, and further characterised by 1H-NMR, UV-Vis, and FT-IR spectra. © TÜBITAK Daha fazlası Daha az

Menteş A. | Sezek S. | Hanhan M.E. | Büyükgüngör O.

Makale | 2007 | Turkish Journal of Chemistry31 ( 6 ) , pp.667 - 676

Multidentate N-ligands (Schiff bases) were prepared by the condensation of 2-acetylpyridine or 2-benzoylpyridine, and 1,2-diaminoethane or 1,6-diaminohexane (2:1 ratio) in ethanol. These ligands were reacted with Mo(CO)6 to obtain dinuclear metal tetracarbonyl compounds. Both terminal amine groups were seen to form imines from the reaction of mono-ketones with diamines in 2:1 or 1:1 ratios. The structures of these ligands and metal complexes were characterized by elemental analysis, and FT-IR, 1H-NMR, 13C-NMR, and LC-MS spectral techniques. N,N'-bis[1-(pyridin-2-yl)ethylidene]ethane-1,2-diamine, which was obtained by the reaction of . . . 2-acetylpyridine and 1,2-diaminoethane, was also characterized by single crystal X-ray structure analysis. The crystal packing is stabilized by intermolecular H-bonding and ?-? interactions. © TÜBİTAK Daha fazlası Daha az

Köse, Mahmut | Orhan, Ersin

Makale | 2009 | Turkish Journal of Chemistry33 ( 5 ) , pp.579 - 588

New thermally stable photochromic fulgimides and benzimidazole[1,2-a]pyrrolidin-2-one derivatives of furylfulgide and thienylfulgide were prepared and their photochromic properties were investigated. Thermal stabilities of some of the new isomers in an alcoholic solution and in PMMA (poly(methyl methacrylate)) polymer films, and pyrolytic behaviors in inert atmosphere with TGA were compared. The colored form of fulgimide and that of benzimidazole[1,2-a]pyrrolidin-2-one derivatives showed large bathochromic shifts for visible absorption maximum compared with the colored form of corresponding fulgides. The imides and benzimidazole[1,2 . . .-a]pyrrolidin-2-one derivatives of fulgide displayed better thermal stability than corresponding fulgides. New thermally stable photochromic fulgimides and benzimidazole[1,2-a]pyrrolidin-2-one derivatives of furylfulgide and thienylfulgide were prepared and their photochromic properties were investigated. Thermal stabilities of some of the new isomers in an alcoholic solution and in PMMA (poly(methyl methacrylate)) polymer films, and pyrolytic behaviors in inert atmosphere with TGA were compared. The colored form of fulgimide and that of benzimidazole[1,2-a]pyrrolidin-2-one derivatives showed large bathochromic shifts for visible absorption maximum compared with the colored form of corresponding fulgides. The imides and benzimidazole[1,2-a]pyrrolidin-2-one derivatives of fulgide displayed better thermal stability than corresponding fulgides Daha fazlası Daha az

Kızgut, Sait | Çuhadaroğlu, Dilek | Toroğlu, İhsan

Diğer | 2003 | Turkish Journal of Chemistry27 ( 4 ) , pp.521 - 528

This study focused on the thermal gravimetric characterization of Turkish bituminous coals for combustion. The combustion properties considered were based on the burning profile of coal samples and their chars produced in a PL 1500 TGA apparatus. The coal seam samples used in the study were obtained from TTK (Turkish Hardcoal Enterprise) mines as channel samples. The majority of the samples from 12 seams were medium-volatile bituminous and only three of them were high-volatile bituminous. Combustion profile parameters of coal samples and chars were correlated with petrographic, proximate and ultimate analysis data in order to establ . . .ish the combustion differences of the samples. The results indicated that only the combustion profile parameters of ignition and burnoff temperatures of coal were correlated with H/C ratio, fuel ratio and petrofactor. The amount of total reactive macerals showed a strong relationship with char reactivity for the same rank coal samples. However, the same result was not obtained for the whole range of coal samples, since rank effect was not included. The petrofactor, combining both effects of petrographic composition and reflectance data, showed a strong relationship with char reactivity for the whole range of coal samples. This study focused on the thermal gravimetric characterization of Turkish bituminous coals for combustion. The combustion properties considered were based on the burning profile of coal samples and their chars produced in a PL 1500 TGA apparatus. The coal seam samples used in the study were obtained from TTK (Turkish Hardcoal Enterprise) mines as channel samples. The majority of the samples from 12 seams were medium-volatile bituminous and only three of them were high-volatile bituminous. Combustion profile parameters of coal samples and chars were correlated with petrographic, proximate and ultimate analysis data in order to establish the combustion differences of the samples. The results indicated that only the combustion profile parameters of ignition and burnoff temperatures of coal were correlated with H/C ratio, fuel ratio and petrofactor. The amount of total reactive macerals showed a strong relationship with char reactivity for the same rank coal samples. However, the same result was not obtained for the whole range of coal samples, since rank effect was not included. The petrofactor, combining both effects of petrographic composition and reflectance data, showed a strong relationship with char reactivity for the whole range of coal samples Daha fazlası Daha az

Bal M. | Ceyhan G. | Avar B. | Köse M. | Kayraldiz A. | Kurtöglu M.

Makale | 2014 | Turkish Journal of Chemistry38 ( 2 ) , pp.222 - 241

A new, substituted 2-[(E) -f[4-(benzyloxy)phenyl]iminog methyl]-4-[(E)-(4-nitrophenyl)diazenyl]phenol azoazomethine ligand (mbH) was synthesized from 2-hydroxy-5-[(4-nitrophenyl)diazenyl]benzaldehyde and 4-benzyloxyanilinehydrochloride in ethyl alcohol solution. These mononuclear Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) complexes of the ligand were prepared and their structures were proposed by elemental analysis, and infrared and ultraviolet-visible spectroscopy; the proton NMR spectrum of the mbH ligand was also recorded. The azo-azomethine ligand, mbH, behaves as a bidentate ligand coordinating through the nitrogen atom of the . . .azomethine (-CH=N-) and the oxygen atom of the phenolic group. Elemental analyses indicated that the metal:ligand ratio was 1:2 in the metal chelates. Powder X-ray diffraction parameters suggested a monoclinic system for the mbH ligand and its Ni(II), Cu(II), Co(II), and Zn(II) complexes, and an orthorhombic system for the Mn(II) complex. Electrochemical properties of the ligand and its metal complexes were investigated in 1 × 10-3 -1 × 10-4 M DMF and CH3CN solvent in the range 200, 250, and 500 mV s-1 scan rates. The ligand showed both reversible and irreversible processes at these scan rates. In addition, genotoxic properties of the ligand and its complexes were examined. © Tubitak Daha fazlası Daha az

Şengül A.

Makale | 2004 | Turkish Journal of Chemistry28 ( 6 ) , pp.703 - 713

2,2'-Bipyridyl-3,3'-dicarboxylic acid (H2BDC) spontaneously resolves on crystallization from water, giving monohydrated crystals of the space group P212121. In any individual crystal, all the atropisomeric-skewed molecules are of one hand; however, on dissolution in water, optical activity is lost. Strong hydrogen bonding leads to a helical structure, via O-H?N links, and 3 further strong bonds between water and carboxylate groups produce a framework structure. The pKa values measured for H2BDC (3.18 ± 0.04 and 4.59 ± 0.02 at 20 ± 1°C, in dilute aqueous solution) agree with the zwitterionic form. The reaction of H2BDC with potassium . . . tetrachloroplatinate(II) in water gives Pt(H2BDC)Cl 2·H2O. The complex was characterized by elemental analysis and spectroscopic techniques Daha fazlası Daha az

Kizgut S. | Çuhadaroglu D. | Toroglu I.

Makale | 2003 | Turkish Journal of Chemistry27 ( 4 ) , pp.521 - 528

This study focused on the thermal gravimetric characterization of Turkish bituminous coals for combustion. The combustion properties considered were based on the burning profile of coal samples and their chars produced in a PL 1500 TGA apparatus. The coal seam samples used in the study were obtained from TTK (Turkish Hardcoal Enterprise) mines as channel samples. The majority of the samples from 12 seams were medium-volatile bituminous and only three of them were high-volatile bituminous. Combustion profile parameters of coal samples and chars were correlated with petrographic, proximate and ultimate analysis data in order to establ . . .ish the combustion differences of the samples. The results indicated that only the combustion profile parameters of ignition and burnoff temperatures of coal were correlated with H/C ratio, fuel ratio and petrofactor. The amount of total reactive macerals showed a strong relationship with char reactivity for the same rank coal samples. However, the same result was not obtained for the whole range of coal samples, since rank effect was not included. The petrofactor, combining both effects of petrographic composition and reflectance data, showed a strong relationship with char reactivity for the whole range of coal samples Daha fazlası Daha az

Şengül, Abdurrahman | Ağac, Hakan | Çoban, Burak | Eroğlu, Erol

Makale | 2011 | Turkish Journal of Chemistry35 ( 1 ) , pp.25 - 36

The tetradentate ligand 6,6' -diacetyl-2,2' -bipyridine dioxime (L) was obtained in high yield by the condensation reaction of 6,6' -diacetyl-2,2'-bipyridine with hydroxyl amine in alkaline solution. Density functional calculations and 3D modeling of the structure at the B3LYP/6-31G(d) level of theory for L revealed that the energy difference between the global trans conformer (trans-L), which possesses the C2h point group, and the distorted cis conformer (cis-L) was 5.214 kcal/mol. Synthesis and characterization of the metal complexes with Cu(I), Cu(II), Pt(II), and Pd(II) metal ions were reported. L acted as a N4 - donor ligand to . . . coordinate to the metal centers via N atoms of the 2,2? -bipyridine and the imine moieties to afford tetrahedral complex [CuI L]PF6 (1), distorted octahedral complex [CuII L(OH2)2 ](NO3)2 (2), and square-planar complexes [Pt II L]Cl 2 (3) and [PdII L]Cl (4), respectively. The CHN analysis for 1 implies that L coordinated to 2 copper(I) ions as a bridging ligand to form a dinuclear metal complex, [Cu2L2 ]2+ , due to the twisting of the coordinated bonds exposed by the tetrahedral geometry preference for the metal ion. The ligand formed intramolecular hydrogen bonds between the oxime groups in 4, as revealed by the spectroscopic studies. The most stable conformations of the compounds were obtained by using the molecular mechanics optimization feature in CAChe software with an augmented MM2 force field. 1 The tetradentate ligand 6,6' -diacetyl-2,2' -bipyridine dioxime (L) was obtained in high yield by the condensation reaction of 6,6' -diacetyl-2,2'-bipyridine with hydroxyl amine in alkaline solution. Density functional calculations and 3D modeling of the structure at the B3LYP/6-31G(d) level of theory for L revealed that the energy difference between the global trans conformer (trans-L), which possesses the C2h point group, and the distorted cis conformer (cis-L) was 5.214 kcal/mol. Synthesis and characterization of the metal complexes with Cu(I), Cu(II), Pt(II), and Pd(II) metal ions were reported. L acted as a N4 - donor ligand to coordinate to the metal centers via N atoms of the 2,2? -bipyridine and the imine moieties to afford tetrahedral complex [CuI L]PF6 (1), distorted octahedral complex [CuII L(OH2)2 ](NO3)2 (2), and square-planar complexes [Pt II L]Cl 2 (3) and [PdII L]Cl (4), respectively. The CHN analysis for 1 implies that L coordinated to 2 copper(I) ions as a bridging ligand to form a dinuclear metal complex, [Cu2L2 ]2+ , due to the twisting of the coordinated bonds exposed by the tetrahedral geometry preference for the metal ion. The ligand formed intramolecular hydrogen bonds between the oxime groups in 4, as revealed by the spectroscopic studies. The most stable conformations of the compounds were obtained by using the molecular mechanics optimization feature in CAChe software with an augmented MM2 force field. Daha fazlası Daha az