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Investigation of Nickel Ion Release from Stainless Steel Crowns by Square Wave Voltammetry
(International Journal of Electrochemical Science, 2012) Menek, Necati; Başaran, Serpil; Karaman, Yeliz; Ceylan, Gözlem; Şen Tunç, Emine
No effort has been made to define nickel magnitude from stainless steel crowns in oral environment. Nickel ions released in sufficient quantities from nickel-containing alloys may induce nickel sensitization or elicit allergic contact dermatitis. In this work nickel ion release from stainless steel crowns in artificial saliva at different days and pH’s has been investigated which is used in pediatric dentistry. Totally 120 stainless steel crowns for primary teeth were immersed to artificial saliva in this study. Nickel in aqueous solutions was determined by square wave voltammetry, using dimethylglyoxime as a complexion agent on mercury electrode. The study revealed that nickel ion release was decreased with increasing pH. Furthermore nickel releasing ratio was decreased in all time periods. Results showed that metal ions released in this experimental condition were well below the critical value to induce allergy and below daily dietary intake level.
Investigation of Electrochemical Behaviour of 3-Allyl-4-Hydroxy-3'-4'- Dimethylazobenzene
(International Journal of Electrochemical Science, 2013) Menek, Necati; Başaran, Serpil; Karaman, Yeliz; Topçu, Saim
The reductive voltammetric and polarographic behaviour of the 3-allyl-4-hydroxy-3'-4' dimethylazobenzene at a hanging mercury drop electrode (HMDE) and static mercury drop electrode (SMDE) has been studied in Britton-Robinson (B-R) buffers in the pH range of 2.0-12.0. The 3-allyl-4-hydroxy-3'-4' dimethylazobenzene gave one voltammetric and polarographic peak, corresponding to the reduction of the azo group to hydrazo and amine. The reduction process was found to be dependent on the pH of the supporting electrolyte. The reduction of the azo group to amino group in acidic media and hydrazo step in neutral and basic media was observed. From the observation an electrode reaction mechanism has been suggested for the compound.
Investigation of Catalytic Effect Nitrite on Electrochemical Reduction of Cobalt Dimethylglyoxime Complex by Polarographic and Voltammetric Techniques
(International Journal of Electrochemical Science, 2014) Menek, Necati; Uçarlı, Okan; Topçu, Saim; Zeyrekli, Serpil; Karaman, Yeliz
The voltammetric and polarographic behaviour of Cobalt Dimethylglyoxime (Co-DMG) complex on a hanging mercury drop electrode (HMDE) and static mercury drop electrode (SMDE) has been studied by several techniques including Square wave voltammetry (SWV), Differential pulse polarography (DPP) and stripping techniques. Polarographic and voltammetric curves recorded at HMDE and SMDE provide information about electrode reaction mechanism. Catalytic effect of nitrite on the electrochemical reduction mechanism of the complex have been explained.
Electrochemical and Spectroscopic Study of 4-(Phenyldiazenyl)-2-{[tris- (hydroxymethyl)methyl]aminomethylene}cyclohexa-3,5-dien-1(2H)-one. Mechanism of the Azo and Imine Electroreduction
(Journal of the Brazilian Chemical Society, 2005) Çakır, Semiha; Biçer, Ender; Odabaşoğlu, Mustafa; Albayrak, Çiğdem
O composto 4-(fenildiazenil)-2-{[tris(hidroximetil)metil]aminometileno}ciclohexa-3,5-dien- 1(2H)-ona foi sintetizado e caracterizado por análise elementar, espectroscopia infravermelho, ressonância magnética nuclear, espectro eletrônico e voltametria cíclica. O equilíbrio tautomérico do 4-(fenildiazenil)-2-{[tris(hidroximetil)metil]aminometileno} ciclohexa-3,5-dien-1(2H)-ona emdimeteilsulfóxido deuterado é comprovado por dados de 1H RMN. A natureza do processo eletroquímico do 4-(fenildiazenil)-2-{[tris(hidroximetil)metil]aminometileno} ciclohexa-3,5-dien-1(2H)-ona em solução tampão de Britton-Robinson (pH 2-9) foi estudada com o eletrodo gotejante de mercúrio utilizando voltametria de onda quadrada, onda quadrada adsortiva e voltametria cíclica. Os parâmetros eletroquímicos do composto (Ip/Ep, Ip/v, Ip/pH, Ip/t acc) foram determinados. Newly synthesized 4-(phenyldiazenyl)-2-{[tris(hydroxymethyl)methyl]aminomethylene} cyclohexa-3,5-dien-1(2H)-one was characterized by elemental analysis, FT-IR, NMR, electronic spectra, voltammetry. Tautomeric equilibrium of 4-(phenyldiazenyl)-2-{[tris(hydroxymethyl) methyl]aminomethylene}cyclohexa-3,5-dien-1(2H)-one in DMSO dis supported by 1H NMR data. The nature of electrochemical process of 4-(phenyldiazenyl)-2-{[tris(hydroxymethyl) methyl]aminomethylene}cyclohexa-3,5-dien-1(2H)-one in Britton-Robinson buffer (pH 2–9) was studied on the HMDE by square-wave (SWV), adsorptive stripping square-wave (AdSWV) and cyclic voltammetry (CV). The electrochemical parameters (Ip/Ep,Ip/v,Ip/pH,Ip/tacc) of the compound were determined.
X-ray and computational structural study of (E)-2-(4-chlorophenyliminomethyl)-4-methoxyphenol
(Acta Crystallographica Section E, 2008) Özek, Arzu; Büyükgüngör, Orhan; Albayrak, Çiğdem; Odabaşoğlu, Mustafa
In the molecule of the title compound, C14H12ClNO2, the two aromatic rings are oriented at a dihedral angle of 5.92 (7)°. An intramolecular O-H...N hydrogen bond results in the formation of a nearly planar six-membered ring, which is oriented at dihedral angles of 1.55 (4) and 5.95 (4)° with respect to the phenol and chlorophenyl rings, respectively. In the crystal structure, weak intermolecular C-H...O hydrogen bonds link the molecules into a three-dimensional network.
X-ray crystal and computational structural study of (E)-2-[(2-chlorophenyl)iminomethyl]-4-methoxyphenol
(Acta Crystallographica Section E, 2008) Özek, Arzu; Büyükgüngör, Orhan; Albayrak, Çiğdem; Odabaşoğlu, Mustafa
In the molecule of the title compound, C14H12ClNO, the two aromatic rings are oriented at a dihedral angle of 12.28 (7)°. An intramolecular O-H...N hydrogen bond results in the formation of a nearly planar six-membered ring, which is oriented with respect to the aromatic rings at dihedral angles of 0.18 (5) and 12.10 (6)°. In the crystal structure, weak intermolecular C-H...O hydrogen bonds link the molecules into chains along the c axis. There is a C-H...[pi] contact between the methyl group and the chlorophenyl ring and a [pi]-[pi] contact between the two benzene rings [centroid-centroid distance = 3.866 (1) Å].
(E)-4-Methoxy-2-[3-(trifluoromethyl)phenyliminomethyl]phenol
(Acta Crystallographica Section E, 2009) Keleşoğlu, Zeynep; Büyükgüngör, Orhan; Albayrak, Çiğdem; Odabaşoğlu, Mustafa
The title compound, C15H12F3NO2, adopts the phenol-imine tautomeric form, with the H atom attached to oxygen rather than to nitrogen. There are two independent molecules aligned nearly parallel in the asymmetric unit with their trifloramethyl groups pointing in opposite directions. The dihedral angles between the aromatic rings are 40.43 (1)° in the first molecule and 36.12 (1)° in the second. Strong intramolecular O-H...N hydrogen bonding generates S(6) ring motifs. Weak intermolecular C-H...O hydrogen bonds link the independent molecules separately into sheets normal to [010]. In addition, C-H...[pi] interactions are also observed. The F atoms of the trifluoromethyl groups are disordered over two sets of sites with refined site occupancies of 0.59 (2)/0.41 (2) and 0.62 (3)/0.38 (3), respectively.
(E)-2-[(4-Ethoxyphenyl)iminomethyl]-4-methoxyphenol
(Acta Crystallographica Section E, 2009) Özek, Arzu; Albayrak, Çiğdem; Büyükgüngör, Orhan
In the molecule of the title compound, C16H17NO3, the aromatic rings are oriented at a dihedral angle of 29.25 (8)°. An intramolecular O-H...N hydrogen bond results in the formation of a nearly planar [maximum deviation 0.034 (13) Å] six-membered ring, which is oriented at dihedral angles of 0.91 (1) and 28.91 (12)° with respect to the aromatic rings. The title molecule is a phenol-imine tautomer, as evidenced by C-O, C-N and C-C bond lengths. In the crystal, molecules are linked by intermolecular C-H...O hydrogen bonds that generate C(8) chains.
(E)-3-[(3-Bromophenyl)iminomethyl]benzene-1,2-diol: a combined X-ray and computational structural study
(Acta Crystallographica Section E, 2009) Keleşoğlu, Zeynep; Büyükgüngör, Orhan; Albayrak, Çiğdem; Odabaşoğlu, Mustafa
The title compound, C13H10BrNO2, exists as an enol-imine form in the crystal and adopts an E configuration with respect to the C=N double bond. The molecule is close to planar, with a dihedral angle of 6.88 (14)° between the aromatic rings. Intramolecular O-H...N and O-H...O hydrogen bonds generate S(6) and S(5) ring motifs, respectively. The crystal structure is stabilized by intermolecular O-H...O hydrogen-bond interactions, forming R22(10) and R22(20) chains along [100]. ab initio Hartree-Fock (HF), density-functional theory (DFT) and semi-empirical (AM1 and PM3) calculations and full-geometry optimizations were also performed. Although there are some discrepancies between the experimental and calculated parameters, caused presumably by the O-H...O hydrogen-bond interactions, there is an acceptable general agreement between them.
(Z)-6-[(5-Chloro-2-hydroxyphenyl)aminomethylene]-2-ethoxycyclohexa-2,4-dienone
(Acta Crystallographica Section E, 2009) Özek, Arzu; Albayrak, Çiğdem; Büyükgüngör, Orhan
The title compound, C15H14ClNO3, exists as the keto-amine form in the crystal and two intramolecular N-H...O hydrogen bonds are observed. The aromatic rings are oriented at a dihedral angle of 5.85 (8)°. In the crystal structure, intermolecular O-H...O and C-H...O hydrogen bonds link the molecules into chains. A [pi]-[pi] contact between the benzene rings [centroid-centroid distance = 3.6623 (10) Å] further stabilizes the structure.
3-[(E)-(4-Ethylphenyl)iminomethyl]benzene-1,2-diol
(Acta Crystallographica Section E, 2009) Keleşoğlu, Zeynep; Büyükgüngör, Orhan; Albayrak, Çiğdem; Odabaşoğlu, Mustafa
The title compound, C15H15NO2, adopts the enol-imine tautomeric form. The dihedral angle between the two benzene rings is 48.1 (1)°. Intramolecular O-H...N and O-H...O hydrogen bonds generate S(6) and S(5) ring motifs, respectively. In the crystal, molecules are linked into centrosymmetric R22(10) dimers via pairs of O-H...O hydrogen bonds and the dimers may interact through very weak by [pi]-[pi] interactions [centroid-centroid distance = 4.150 (1) Å]. The ethyl group is disordered over two orientations, with occupancies of 0.587 (11) and 0.413 (11).
(E)-3-[(4-Butylphenyl)iminomethyl]benzene-1,2-diol
(Acta Crystallographica Section E, 2009) Keleşoğlu, Zeynep; Büyükgüngör, Orhan; Albayrak, Çiğdem; Odabaşoğlu, Mustafa
The title compound, C17H19NO2, exists as an enol-imine tautomer. The dihedral angle between the two benzene rings is 4.6 (2)°. The molecular structure is stabilized by intramolecular O-H...O and O-H...N hydrogen bonds which generate S(5) and S(6) ring motifs, respectively. In the crystal, molecules are linked into centrosymmetric dimers by pairs of O-H...O hydrogen bonds. In addition, C-H...[pi] interactions involving both benzene rings are observed.
(Z)-6-[(5-Chloro-2-hydroxyanilino)methylene]-4-methoxycyclohexa-2,4-dienone 0.25-hydrate
(Acta Crystallographica Section E, 2009) Özek, Arzu; Büyükgüngör, Orhan; Albayrak, Çiğdem; Odabaşoğlu, Mustafa
The title compound, C14H12ClNO3·0.25H2O, exists in the keto-amine form, and the aromatic rings are oriented at a dihedral angle of 7.24 (7)°. Bifurcated intramolecular N-H...(O,O) hydrogen bonds result in the formation of planar six- and five-membered rings. In the crystal structure, intermolecular O-H...O and C-H...O hydrogen bonds link the molecules into chains. [pi]-[pi] contacts between benzene rings [centroid-centroid distance = 3.5065 (9) Å] may further stabilize the structure. There also exists a weak C-H...[pi] interaction.
(E)-4-Methoxy-2-(o-tolyliminomethyl)phenol
(Acta Crystallographica Section E, 2009) Özek, Arzu; Büyükgüngör, Orhan; Albayrak, Çiğdem; Odabaşoğlu, Mustafa
In the molecule of the title compound, C15H15NO2, the aromatic rings are oriented at a dihedral angle of 15.46 (6)°. An intramolecular O-H...N hydrogen bond results in the formation of a nearly planar six-membered ring [maximum deviation of 0.035 (5) Å for the N atom] which is almost coplanar with the adjacent ring, making a dihedral angle of 0.8 (3)°. The title organic molecule is a phenol-imine tautomer, as evidenced by the C-O, C-N and C-C bond lengths. Molecules are linked by intermolecular C-H...O hydrogen bonds that generate a C(5) chain. C-H...[pi] and [pi]-[pi] interactions exist in the structure. The [pi]-[pi] interaction occurs between the phenol ring and its symmetry equivalent at (1 - x, 1 - y, -z), with a centroid-centroid distance of 3.727 (7) Å and a plane-to-plane separation of 3.383 (5) Å, resulting in an offset angle of 24.82 (1)°.
3-Diethylamino-6-[(Z)-(4-hydroxyanilino)methylidene]cyclohexa-2,4-dienone
(Acta Crystallographica Section E, 2010) Soydemir, Erkan; Büyükgüngör, Orhan; Albayrak, Çiğdem
In the molecule of the title compound, C17H20N2O2, the aromatic rings are oriented at a dihedral angle of 6.23 (22)°. Intramolecular N-H...O hydrogen bonding involving the amine H atom and the carbonyl O atom affects the conformation of the molecule. One of the ethyl arms is disordered over two conformations, with occupancies of 0.59 (2) and 0.41 (2). The crystal packing is stabilized by intermolecular C-H...O and O-H...O hydrogen bonds, and weak C-H...[pi] interactions.
(E)-2-Acetyl-4-[(3-methylphenyl)diazenyl]phenol: an X-ray and DFT study
(Acta Crystallographica Section E, 2010) Yazıcı, Serap; Albayrak, Çiğdem; Gümrükçüoğlu, İsmail; Şenel, İsmet; Büyükgüngör, Orhan
The title compound, C15H14N2O2, an azo dye, displays a trans configuration with respect to the N=N bridge. The dihedral angle between the aromatic rings is 0.18 (14)°. There is a strong intramolecular O-H...O hydrogen bond. Geometrical parameters, determined using X-ray diffraction techniques, are compared with those calculated by density functional theory (DFT), using hybrid exchange-correlation functional, B3LYP and semi-empirical (PM3) methods.
(E)-2-[(2-Ethylphenyl)iminiomethyl]-6-hydroxyphenolate
(Acta Crystallographica Section E, 2010) Yazıcı, Serap; Albayrak, Çiğdem; Gümrükçüoğlu, İsmail; Şenel, İsmet; Büyükgüngör, Orhan
The molecule of the title compound, C15H15NO2, crystallizes in a zwitterionic form, and displays an E configuration about the C=N bond. The dihedral angle between the two aromatic rings is 5.59 (6)°. An intramolecular N-H...O hydrogen bond generates an S(6) ring motif. In the crystal structure, pairs of molecules are linked into centrosymmetric R22(10) dimers by pairs of O-H...O hydrogen bonds. Aromatic [pi]-[pi] interactions are observed between the benzene rings of adjacent dimers [centroid-centroid distance = 3.4808 (7) Å].
(E)-2-[(2-Ethylphenyl)iminomethyl]-6-methoxyphenol
(Acta Crystallographica Section E, 2010) Yazıcı, Serap; Albayrak, Çiğdem; Gümrükçüoğlu, İsmail; Şenel, İsmet; Büyükgüngör, Orhan
The molecule of the title compound, C16H17NO2, adopts the phenol-imine tautomeric form with a strong intramolecular O-H...N hydrogen bond and an E conformation with respect to the azomethine C=N bond. The dihedral angle between the aromatic rings is 21.23 (9)°. The ethyl group is disordered over two orientations with occupancies of 0.598 (6) and 0.402 (6). In the crystal, the molecules are linked into chains along the b axis by C-H...[pi] interactions.
(E)-2-Hydroxy-6-[(4-propylphenyl)iminiomethyl]phenolate
(Acta Crystallographica Section E, 2009) Yazıcı, Serap; Albayrak, Çiğdem; Gümrükçüoğlu, İsmail; Şenel, İsmet; Büyükgüngör, Orhan
The title compound, C16H17NO2, crystallizes with three crystallographically independent zwitterionic molecules in the asymmetric unit which differ significantly in the orientations of the propyl side chains. The dihedral angles between the two benzene rings in the three molecules are 6.17 (7), 6.75 (7) and 23.67 (7)°, respectively. In each independent molecule, an intramolecular N-H...O hydrogen bond generates an S(6) ring motif. In the crystal, each independent molecule exists as part of an O-H...O hydrogen-bonded centrosymmetric R22(10) dimer.
5-Diethylamino-2-[(E)-(4-ethoxyphenyl)iminomethyl]phenol
(Acta Crystallographica Section E, 2011) Soydemir, Erkan; Büyükgüngör, Orhan; Albayrak, Çiğdem; Odabaşoğlu, Mustafa
The title compound, C19H24N2O2, adopts the phenol-imine tautomeric form. An intramolecular O-H...N hydrogen bond results in the formation of a six-membered ring. The aromatic rings are oriented at a dihedral angle of 17.33 (16)°. Intermolecular C-H...[pi] interactions occur in the crystal.

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