Synthesis and catalytic activities of copper(I) complexes of Bis(diphenylphosphinomethyl)amino ligand and its Silica-supported form

Cu(I) complexes of free ditertiary aminomethylphosphine ligand, N,N-bis(diphenylphosphinomethyl)aminopropyltriethox- ysilane (DIPAPTES) and its silica supported form (SiO2-DIPAPES), have been synthesized under nitrogen atmosphere using Schlenk method and characterized by atomic absorption, FT-IR, NMR (1H and 31P), and elemental analysis. Acetylacetonate (acac)- complexes of Cr(III) and Mn(III) complexes were prepared according to the literature. All the complexes were used as catalysts for the oxidation of 2-methyl naphthalene (2MN) to 2-methyl-1,4-naphthoquinone (Vitamin K3, menadione, 2MNQ) using hydrogen peroxide as a clean and cheap oxidant. All the complexes did not show good catalytic activity for the selective oxidation of 2-methyl naphthalene to 2-methyl-1,4-naphthoquinone. Copyright © Taylor & Francis Group, LLC

Synthesis, characterization, and antimicrobial activities of Cu(I), Ag(I), Au(I), and Co(II) complexes with [CH3N(CH2PPh 2)2]

Transition metal complexes of ditertiary aminomethylphosphine ligand, (Ph2PCH2)NCH3 [N, N-bis (diphenylphospinomethyl)aminomethane], dppam, with metal ions which are Ag(I), Au(I), Cu(I), and Co(II) have been synthesized under nitrogen atmosphere by the Schlenk method. [Ag(dppam)2]NO3 (1), [Au(dppam) 2]Cl (2), and [Cu(dppam)2]Cl (3) complexes have been isolated as colorless solids, whereas [CoCl2 (dppam)J (4) complex as a blue solid. All complexes have been characterized by atomic absorption, FT-IR, NMR (1H, 13C, 31P) spectroscopic, thermogravimetric/differantial thermal analysis (TG/DTA), and elemental analysis techniques. Antimicrobial activity of 1, 2, 3, and 4 were studied in vitro on 13 bacteria and 4 yeasts. The cobalt(II) phosphine complex has shown the best antimicrobial activity in comparison with the other metal complexes. © 2005 Wiley Periodicals, Inc

Synthesis of silica-supported Platinum(II) and nickel(II) complexes of bis(Diphenylphosphinomethyl)amino ligand: Applications as catalysts for the synthesis of 2-Methyl-1,4-Naphthoquinone (vitamin K 3 )

Pt(II) and Ni(II) complexes of N,N-bis(diphenylphosphinomethyl)aminopropyltriethoxysilane [(CH 3 CH 2 O) 3 Si(CH 2 ) 3 N(CH 2 PPh 2 ) 2 ] (DIPAPTES) and silica supported [SiO 2 -(DIPAPES)] ligands have been synthesized under nitrogen atmosphere using Schlenk method and characterized by using atomic absorption, FT-IR, NMR ( 1 H and 31 P) and elemental analysis techniques. All the complexes were used as catalysts for the oxidation of 2-methyl naphthalene (2MN) to 2-methyl-1,4-naphthoquinone (vitamin K 3 , menadione, 2MNQ) using hydrogen peroxide as a clean and cheap oxidant. [Pt-(DIPAPTES)Cl 2 ] and supported complex [SiO 2 -(DIPAPES)-PtCl 2 ] showed medium catalytic activity whereas Ni(II) complexes did not show any catalytic activity for the selective oxidation of 2-methyl naphthalene to 2-methyl-1,4-naphthoquinone. © Springer Science+Business Media, LLC 2010.Acknowledgments We would like to thank to Oxyvit Kimya San.Tic.A.S¸ . for their all supports. The authors also thank to C¸ ukur-ova University (Project No: FEF2007D007) and Sütc¸ü İmam University for financial support

Catalytic synthesis of 2-methyl-1,4-naphthoquinone (vitamin K3) over silica-supported aminomethyl phosphine-Ru(II), Pd(II), and Co(II) complexes

Ru(II), Pd(II), and Co(II) complexes of the free ditertiary aminomethylphosphine ligand, N,N-bis(diphenylphosphinomethyl) aminopropyltriethoxysilane [(EtO)3Si(CH2)3 N(CH2PPh2)2] (DIPAPTES), and its SiO2-DIPAPES have been synthesized under a nitrogen atmosphere using Schlenk techniques. All the complexes were used as catalysts for the oxidation of 2-methyl naphthalene (2MN) to give 2-methyl-1,4-naphthoquinone (vitamin K3, menadione, 2MNQ) in the presence of hydrogen peroxide as a clean and cheap oxidant. The catalytic synthesis of vitamin K3 was investigated using both homogeneous catalysis with free complexes and heterogeneous catalysis with silica-supported complexes. [(DIPAPTES)PdCl2] and its silica-supported form showed the best catalytic activity for the selective oxidation of 2-methyl naphthalene to 2-methyl-1,4-naphtoquinone compared to the other metal complexes. 2MNQ yield reached 52.26% with the 2MN conversion of 90.52% using complex [(DIPAPTES)PdCl2] and 58.59% with the 2MN conversion of 99.56% using the silica supported [SiO2(DIPAPES)PdCl2] complex for 1 h. Recycling was investigated for the silica-supported Pd(II) complex and compared with the classical production of vitamin K3. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file. Copyright © Taylor & Francis Group, LLC

Frequency-Dependent Electrical Characterization of GO-SiO2 Composites in a Schottky Device

An Al/GO-SiO2/p-Si device was obtained via the spin coating technique for the GO-SiO2 interfacial composite layer, and the thermal evaporation technique was employed for Al contacts. The device was subsequently analyzed via impedance spectroscopy for on a wide range of frequency (from 10 kHz to 5 MHz) and voltage (± 1 V) at room temperature. Main electrical parameters including barrier height, series resistance, doping concentration and interface states of the device were calculated using C–V and G–V characteristics. According to the C–V and G–V characteristics, the main electrical parameters were affected by the series resistance and interface states. The device exhibited negative capacitances, and the capacitance and conductance values were found to be a strong function of the frequency and voltage. The Al/GO-SiO2/p-Si device was also characterized via dielectric characterization. The profiles of ?',?¨ tan ?, M'M¨ and ? in relation to frequency and voltage were plotted and are discussed in details. All the dielectric parameters were found to be a strong function of frequency and voltage, and the interface states were more effective at low frequencies for this device. Instead of using only a SiO2 layer in the interface, a GO-SiO2 composite structure can be used as a new material for more effective metal–oxide–semiconductor (MOS) devices. © 2018, The Minerals, Metals & Materials Society

The structural analysis of MWCNT-SiO2 and electrical properties on device application

Al/MWCNT-SiO2/p-Si device were obtained using chemical techniques and characterized using the I-V (under dark and light conditions) and C-V measurements depending on various frequency. MWCNT-SiO2 composite layer of the device were also characterized using XRD, FTIR, SEM, TEM and TGA measurements. These all results indicated that the MWCNT-SiO2 layer synthesized successfully on Si wafer as a composite form with chemical processes and spin coating. I-V measurements showed that device has good rectifying properties, small saturation current and good photodiode properties. Solar cell conversion efficiency (?p) and fill factor (FF) values of the device also were calculated as 0.12% and 47.6%, respectively. It could be seen from C-V measurements that capacitance and conductance properties of the device strongly depended on frequency and voltage. It may be used and improved this device as rectifier, photodiode and capacitor in the future. © 2017 Elsevier B.V.111T211We would like to thank The Scientific & Technological Research Council of Turkey (T?B?TAK) (Project No: 111T211) and Kahramanmara? S?t?? ?mam University (Project No: 2013/6?33?M and 2015/2?13 YLS) for their financial supports

The structural and electrical characterization of Al/GO-SiO2/p-Si photodiode

GO-SiO2 composite structures were synthesized chemically and characterized by FTIR, XRD, TGA and SEM. The characterization results highlighted that the composite of the GO-SiO2 was obtained successfully and can be thought as interfacial layer between the metal and semiconductor. For that reason, the GO-SiO2 composites were inserted between Al metal and p-type Si semiconductor by spin coating technique, and Al/GO-SiO2/p-type Si device was obtained by aid of thermal evaporation. The obtained device was tested with I-V measurements for various illumination conditions. Ideality factor, barrier height and series resistance values were determined according to thermionic emission theory, Cheung and Norde functions. In addition, we studied transient photocurrent properties of the device. The results confirm that the device can be used as photodiode in the industrial applications as having good photostability and photoresponsivity. © 2018 Elsevier B.V

The synthesis, characterization, antimicrobial and antimutagenic activities of hydroxyphenylimino ligands and their metal complexes of usnic acid isolated from Usnea longissima

PubMed ID: 24589530Novel multifunctional hydroxyphenylimino ligands (L1, L2 and L3) were synthesized by the condensation of 2-aminophenol, 3-aminophenol and 4-aminophenol with usnic acid, a lichen metabolite. The synthesized ligands and their Cu(ii), Co(ii), Ni(ii) and Mn(ii) complexes were characterized using FT-IR, UV-Vis, 1H-NMR, 13C-NMR, 1D- and 2D NMR (DEPT, COSY, HMQC and HMBC), LC-MS and TGA. In addition, the metal complexes of the novel ligands were prepared with high yields using Cu(ii), Co(ii), Ni(ii) and Mn(ii) salts and were characterized using the FT-MIR/FAR, UV-Vis, elemental analysis, ICP-OES and TG/DTA techniques. The ligands and their complexes were tested against ten important pathogen microorganisms using the disc diffusion method and the metal complexes of the ligands were more active against all of the microorganisms tested with a broad spectrum than the ligands exhibiting 11–32 mm inhibition zones. On the other hand, a broad spectrum of the strongest antimicrobial activity was determined for the Mn(ii) and Cu(ii) complexes of the hydroxyphenylimino ligand with usnic acid (L3). In addition, the antimutagenic activities of all of the ligands and their metal complexes were determined using the Ames-Salmonella and E. coli WP2 microbial assay systems and they showed varied and strong antimutagenic effects. In general, it has been found that the Co and Mn complexes of the ligands possess potent antimutagenic activity. In view of these results, it can be concluded that some metal complexes can be used as antimicrobial and anticancer agents. © 2014 The Partner Organisations