Mustafa Keleş

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 publishers online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.

Hydrogenation of Acetophenone and Its Derivatives with 2-Propanol Using Aminomethylphosphine-Ruthenium Catalysis

The reaction of 3′-aminopropyltriethoxysilane with the phosphonium salt ([Ph2P(CH2OH)2]Cl) gives an aminomethylphosphine-type ligand ((CH3CH2O)3Si(CH2)3N(CH2PPh2)2). Reaction of the ligand ((CH3CH2O)3Si(CH2)3N(CH2PPh2)2) with silica gives silica supported aminomethylphosphine ligand (SiO2)-O-Si(CH2)3N(CH2PPh2)2). The ligands were refluxed with [RuCl2(p-cymene)]2 in toluene to give [RuCl2((CH3CH2O)3Si(CH2)3N(CH2PPh2)2)] and silica-supported SiO2)-O-[RuCl2((Si(CH2)3N(CH2PPh2)2)2] complex, respectively. The catalytic studies show that the complexes [RuCl2((CH3CH2O)3Si(CH2)3N(CH2PPh2)2)] and SiO2)-O-[RuCl2((CH3CH2O)3Si(CH2)3N(CH2PPh2)2)2] are very active catalysts for the transfer hydrogenation of acetophenone by 2-propanol in basic media. The best yield was observed in hydrogenation of m-methoxy acetophenone (95%) with catalyst [RuCl2((CH3CH2O)3Si(CH2)3N(CH2PPh2)2)].

Preparation of Heterogeneous Palladium Catalysts Supported on Sporopollenin for Heck Coupling Reactions

The immobilized Schiff bases, S-[N-(2-aminoethyl)salicylal diimino] (1a), S-[N-(2-aminoethyl)cinnamaldiimino] (1b), S-[N-(2-aminoethyl)acetaldiimino] (1c), and their palladium(II) (2a–c) complexes, were synthesized onto a chemically modified sporopollenin with ethylenediamine. These complexes were investigated as catalysts in a Heck reaction of aryl halide with olefins. These immobilized palladium complexes is an efficient catalysts for Heck reaction of aryl halides with methyl and butyl acrylate.

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.

Adsorption and anticorrosion behaviour of an imine compound on low carbon steel in HCl solution at different potentials

Abstract The inhibition capability of an imine compound named (2-methoxyphenyl)-N-(2-(phenylthio)phenyl)methanimine (MPM) on low carbon steel corrosion in HCl solution was investigated at various concentrations and temperatures by using electrochemical and microscopic techniques. The electrochemical results revealed that the inhibition efficiency increases with an increase in the MPM concentration, and MPM has provided 98.8% protection for 120 h. Electrochemical studies at different potentials showed that electrostatic effects have an important role on the adsorption of MPM on the metal surface. scanning electron microscopy and energy-dispersive X-ray spectroscopy results also confirmed that MPM has reduced the corrosive effect of HCl.

Multi-walled carbon nanotube supported aminomethylphosphine-Ru(II) complexes: Optical behavior and catalytic properties in transfer hydrogenation of acetophenone derivatives

ABSTRACT The novel multi-walled carbon nanotube (MWCNT) supported bis(diphenylphosphinomethyl)amine [MWCNT@CHO-NHArN(CH2PPh2)2 type] ligands and their Ru(II) complexes have been synthesized and characterized with Fourier Transform Infrared Spectrometry (FT-IR), Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray (EDX), Transmission Electron Microscopy (TEM), Ultraviolet-Visible Spectrometry, X-Ray Diffraction Spectrometry (XRD), and Thermal analysis (TG/DTA) techniques. In addition, MWCNT@CHO-NHArN(CH2PPh2)2Ru(p-cymene)Cl2 type complexes were tried as catalysts in the catalytic transfer hydrogenation reactions of acetophenone derivatives. The crystallite size and lattice strain of the MWCNT-based compounds were calculated by the Scherrers equation. The optical parameters of the MWCNT-based structures were analyzed and the band gap enhanced from 4.42 eV to 4.98 eV. It was confirmed that the reduction of bromo and chloro acetophenone derivatives using all the catalysts, the conversions were high. The results showed that MWCNT-supported Ru(II) complexes were efficient catalysts in the reduction of bromo and chloro acetophenone derivatives with 99% efficiency in K2CO3 media at 80 °C.

Correction to: 3-Aminoquinazolinone–phosphine ligands and their ruthenium(II) complexes: application in catalytic hydrogenation and transfer hydrogenation reactions

In the initial online publication, there was a mistake in the title. The first words read “3-Aminoquinazolinone–phosphine” instead of “3-Aminoquinazolinone–phosphine”. The original article has been corrected.

Protection Effect of 2-(phenylthio)phenyl)-1-(2- (trifluoromethyl)phenyl) methanimine on Low Carbon Steel at Open Circuit and Different Potentials

The inhibition capability of (2-(phenylthio)phenyl)-1-(2-(trifluoromethyl)phenyl) methanimine (PFM) on corrosion of low carbon steel (LCS) in 1.0 M HCl solution was investigated at various potentials and temperatures using electrochemical and microscopic techniques. The electrochemical results showed that the inhibition efficiency increases with increasing PFM concentration. Besides this electrochemical studies at open circuit and different potentiostatic potentials showed that electrostatic effects have an important role on the adsorption of PFM on the metal surface. Time dependent stability of the inhibitor was also investigated by Electrochemical Impedance Spectroscopy (EIS), Scanning Electron Microscopy (SEM) and Energy-dispersive X-ray spectroscopy (EDS). The results confirmed that PFM has reduced the corrosive effect of HCl on low carbon steel even 120 h later.

Synthesis of Some Nickel(II) Diphosphine Complexes Having Coordinated Carboxylates

Treatment of aminobis(methylphosphine) complexes of nickel(II) with carboxylic acids in the presence of silver(I) salts in dichloromethane gives the corresponding nickel(II) complexes of the type [NiA(P-P] where A = CO3 −− (carbonate), (2),2-− OC6H4CO2 − (salicylate, Sal), (3),−O2CCH2CH2 CH(NH2)CO2 − (glutamate, Glu), (4), −O2 CCH2CH2CO2 − (succinicate, Suc), (5); P-P = (Cy2PCH2)2NMe (dcpam), (Ph2PCH2)2NMe (dppam). The complexes have been characterized by spectroscopic techniques such as 31P-{1H} NMR, FT-IR, UV-Vis. and mass spectrometry.