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An environmental catalyst derived from biological waste materials for green synthesis of biaryls via Suzuki coupling reactions
Dergi Makalesi

Dergi Makalesi Open Access
Kaynak :
DSpace Makaleler
Yayıncı :
Journal of Molecular Catalysis A-Chemical
Yazar(lar) :
Talat Baran , İdris Sargın , Murat Kaya , Ayfer Menteş
Konu :
Chitosan, Algae, Eco-friendly, Palladium, Microwave
Yıl :
2016
Journal of Molecular Catalysis A-Chemical
Yayıncı Web Sitesi Tam Metin
Kaydet
Synthesis of bio-macromolecular supported catalysts has gained much recent attention due to their greener nature. Among the biopolymers, chitosan is widely used as a support material due to its high affinity for metal ions. In this study, chitosan-Ulva sp. (green alga) composite microbeads were prepared as a support material for palladium catalyst. Ulva sp. particles were incorporated into chitosan matrix to enhance the interaction with palladium ions. The catalytic performance of chitosan-Ulva supported Pd(II) catalyst was investigated in the synthesis of biaryls via the Suzuki coupling reaction. All the experiments were conducted without using any solvent under the microwave irradiation, which is also considered as a green technique. This green catalyst exhibited high selectivity and efficiency in the reactions of phenyl boronic acid with different aryl halides in only 4 min at low temperature (50 degrees C). Excellent TON and TOF values were achieved for the catalyst; 4950 and 75000. In addition, the catalyst did not lose its activity even after 8 cycles. It showed high thermal stability (216.8 degrees C) and durability in presence of oxygen. This green catalyst has a potential to be used in pharmacology, medicine and cosmetics. (c) 2016 Elsevier B.V. All rights reserved.
Anahtar Kelimeler : Chitosan, Algae, Eco-friendly, Palladium, Microwave, article
Cilt: 420
ISSN: 1381-1169
Sınıflandırma :
Kimya %100
Kataliz %76
2
Routes of formation and composition of NOx complexes adsorbed on palladium-promoted tungstated zirconia
Dergi Makalesi

Dergi Makalesi Open Access
Kaynak :
DSpace Makaleler
Yayıncı :
Journal of Molecular Catalysis A: Chemical
Yazar(lar) :
M. Kantcheva , I. Cayirtepe
Konu :
FT-IR spectroscopy, NOO2 coadsorption, NOx adsorbed species, PdWO 3 - ZrO2, WO3 - ZrO2, Complexation, Fourier transform infrared spectroscopy, Palladium, Thermal effects, Zirconia, NO adsorption, NOOsub2sub coadsorption, NOsubxsub adsorbed species, PdWO sub3sub - ZrOsub2sub, WOsub3sub - ZrOsub2sub, Nitrogen oxides
Yıl :
2006
Journal of Molecular Catalysis A: Chemical
Yayıncı Web Sitesi Tam Metin
Kaydet
Surface species obtained during the adsorption of NO and NO/O2 coadsorption at room temperature on Pd-free (WZ) and Pd-promoted tungstated zirconia (Pd/WZ) are identified by means of in situ FT-IR spectroscopy. The WZ and Pd/WZ samples have a tetragonal structure and contain randomly distributed mesoporous phase. Dispersed palladium(II) species are present in two different environments: (i) Pd2+ ions, which have only Zr4+ ions in their second coordination sphere and (ii) Pd2+ ions, which are linked to both zirconium and tungsten ions via oxygen bridges. On the Pd/WZ sample, NO undergoes oxidation to various NOx species depending on the temperature. The compounds formed at room-temperature oxidation are adsorbed N2O3 and products of its self-ionization, NO+ and NO2-. In this process W(VI) is involved, being reduced to W(IV). At high temperature N2O3 decomposes, restoring the WO species. Under these conditions, NO undergoes oxidation to NO2 by the Pd(II) ions, which are reduced to Pd(I). The nitrosyls of Pd(I) display high thermal stability and do not disappear upon evacuation at 623 K. During NO/O2 coadsorption on the Pd/WZ catalyst at room temperature, the amounts of surface nitrates and NO2/N2O4 formed in the gas phase are significantly lower than those observed under identical conditions in the presence of tungstated zirconia. It is concluded that promotion of tungstated zirconia with palladium(II) suppresses the oxidation of NO by molecular oxygen at room temperature due to the elimination of acidic protons involved in the process. © 2005 Elsevier B.V. All rights reserved.
DOI : 10.1016/j.molcata.2005.11.022
Anahtar Kelimeler : FT-IR spectroscopy, NOO2 coadsorption, NOx adsorbed species, PdWO 3 - ZrO2, WO3 - ZrO2, Complexation, Fourier transform infrared spectroscopy, Palladium, Thermal effects, Zirconia, NO adsorption, NOOsub2sub coadsorption, NOsubxsub adsorbed species, PdWO sub3sub - ZrOsub2sub, WOsub3sub - ZrOsub2sub, Nitrogen oxides, Article
Cilt: 247
Sayı: 1-2
ISSN: 1381-1169
Sayfa: 88-98
Sınıflandırma :
Kimya %79
Kataliz %99
3
Synthesis and immobilization of N-heterocyclic carbene complexes of Ru(II): catalytic activity and recyclability for the furan formation
Dergi Makalesi

Dergi Makalesi
Kaynak :
DSpace Makaleler
Yayıncı :
Journal of Molecular Catalysis A-Chemical
Yazar(lar) :
Cetinkaya , B , Gurbuz , N , Seckin , T , Ozdemir , I
Konu :
N-heterocyclic carbenes, ruthenium complexes, immobilization, catalysts for furan formation
Yıl :
2002
Journal of Molecular Catalysis A-Chemical
Yayıncı Web Sitesi
Kaydet
Synthesis, characterization and immobilization of ruthenium(II) complexes of the type [RuCl2L(eta(6)-arene)] (L=CN(CH2PH)CH2CH2N(CH2)(3)Si(OEt)(3), arene = p-cymene, 3 and arene = C6Me6, 4) and [RuCl2L] (L = eta(1)-carbene-eta(6)-arene bidentate ligand, CN[(CH2)(3)Si(OEt)(3)]CH2CH2NCH2C6H2Me3-eta(6)), 5, morphologically different silicas by sol-gel method are described and their reactivity and recyclability in the furan formation were also reported. (C) 2002 Elsevier Science B.V. All rights reserved.
Anahtar Kelimeler : N-heterocyclic carbenes, ruthenium complexes, immobilization, catalysts for furan formation, article
Cilt: 184
Sayı: 01.Feb
ISSN: 1381-1169
Sınıflandırma :
4
Isomerisation of ?-pinene over Beta zeolites synthesised by different methods
Dergi Makalesi

Dergi Makalesi
Kaynak :
DSpace Makaleler
Yayıncı :
Journal of Molecular Catalysis A: Chemical
Yazar(lar) :
Gündüz G. , Dimitrova R. , Yilmaz S. , Dimitrov L. , Spassova M.
Konu :
?-Pinene, Beta zeolite, Isomerisation, Mesopores
Yıl :
2005
Journal of Molecular Catalysis A: Chemical
Yayıncı Web Sitesi
Kaydet
Liquid-phase ?-pinene isomerisation at l00°C in a batch reactor is studied over Beta zeolites synthesised by different methods. It is confirmed that ?-pinene forms a carbenium ion in an acidic environment, which rearranges without capture by nucleophiles, to form mainly hydrocarbons as camphene, terpinenes, terpinolenes and heavy products. The microporous Beta samples show low activity despite the high acidity most probably because of the hindered intermediate formation. The nature of the enhanced activity of Beta mesopores samples is suggested to be a result from the high accessibility of the acidic sites. The isomerisation of ?-pinene was studied over Beta zeolites synthesised by different methods. The main products are camphene, terpinenes, terpinolenes and heavy products. Beta zeolites with micro-/mesopores reveal excellent activity because of the appropriate balance between acidity and bimodal pore system. The microporous Beta samples show low activity despite the good total acidity most probably because of the steric effect for the formation of the intermediate cations. © 2004 Elsevier B.V. All rights reserved.
Anahtar Kelimeler : ?-Pinene, Beta zeolite, Isomerisation, Mesopores, article
Cilt: 225
Sayı: 2
ISSN: 1381-1169
Sınıflandırma :
Kimya %100
Kataliz %97
5
Ruthenium(II) complexes with 2,6-pyridyl-diimine ligands: synthesis, characterization and catalytic activity in epoxidation reactions
Dergi Makalesi

Dergi Makalesi
Kaynak :
DSpace Makaleler
Yayıncı :
Journal of Molecular Catalysis A-Chemical
Yazar(lar) :
Cetinkaya , B , Cetinkaya , E , Brookhart , M , White , PS
Konu :
pyridine-2, 6-diimines, ruthenium(II) complexes, epoxidation catalysts, epoxidation of cyclohexene, X-ray structure of Ru(II)
Yıl :
1999
Journal of Molecular Catalysis A-Chemical
Yayıncı Web Sitesi
Kaydet
Reaction of [RuCl2(p-cymene)](2) with the tridentate N-N-N ligands, 2,6-pyridyl-diimines, led to substitution of p-cymene. The resulting complexes, believed to be coordinatively unsaturated, exhibit efficient activity for the epoxidation of cyclohexene in the presence of iodosobenzene (PhIO): the complexes formed initially take up donor molecules such as acetonitrile to achieve hexacoordination. The molecular structure for one of these, (acetonitrile){2,6-bis[1-(4-methoxyphenylimino)ethyl]pyridine}dichlororuthenium(II), 2, has been determined by X-ray diffraction. The immediate coordination sphere is a distorted octahedron with trans chloride atoms and a short Ru-N(py) (1.906 Angstrom) bond. (C) 1999 Elsevier Science B.V. All rights reserved.
Anahtar Kelimeler : pyridine-2, 6-diimines, ruthenium(II) complexes, epoxidation catalysts, epoxidation of cyclohexene, X-ray structure of Ru(II), article
Cilt: 142
Sayı: 2
ISSN: 1381-1169
Sınıflandırma :
6
Water-soluble cis-(NHC)PdBr2(TPPTS) catalysts and their applications in Suzuki-Miyaura coupling of aryl chlorides
Dergi Makalesi

Dergi Makalesi
Kaynak :
DSpace Makaleler
Yayıncı :
Journal of Molecular Catalysis A-Chemical
Yazar(lar) :
Turkmen Hayati , Pelit Levent , Cetinkaya Bekir
Konu :
Water soluble complexes, Cross-coupling, Palladium, Electronic effects, NHC
Yıl :
2011
Journal of Molecular Catalysis A-Chemical
Yayıncı Web Sitesi
Kaydet
New palladium(II) complexes (2), bearing NHC/TPPTS ligands, (NHC = benzimidazol-2-ylidene; TPPTS = triphenylphosphine-3,3,3 -trisulfonic acid trisodium salt) have been prepared and characterized by elemental analyses and spectroscopic methods. Their ability to catalyze the Suzuki-Miyaura reaction in neat water has been studied at 100 degrees C. Very high activities have been observed in the coupling of phenylboronic acid with aryl chlorides in the presence of 1% of the catalyst. We have compared the electronic properties of cis-[PdBr2(NHC)(TPPTS)] with the related complexes, [PdX2(NHC)](2) and [trans-PdBr2(NHC)(pdca)](Pdca = pyridine-2,6-dicarboxyic acid) (3) via three different techniques: cyclic voltammetry, thermogravimetric analysis and C-13 NMR spectroscopy. Crown Copyright (C) 2011 Published by Elsevier B.V. All rights reserved.
Anahtar Kelimeler : Water soluble complexes, Cross-coupling, Palladium, Electronic effects, NHC, article
Cilt: 348
Sayı: 01.Feb
ISSN: 1381-1169
Sınıflandırma :
7
Mono- and binuclear ruthenium(II) complexes containing pyridine-2,6-diimine (Pydim) ligands: Synthesis, characterization and catalytic activity in the transfer hydrogenation of acetophenone
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Dergi Makalesi
Kaynak :
DSpace Makaleler
Yayıncı :
Journal of Molecular Catalysis A-Chemical
Yazar(lar) :
Dayan Osman , Cetinkaya Bekir
Konu :
tridentate triamine ligands, pyridine-2, 6-diimines, Ru(II) complexes, transfer hydrogenation of acetophenone
Yıl :
2007
Journal of Molecular Catalysis A-Chemical
Yayıncı Web Sitesi
Kaydet
A series of neutral mono- and binuclear Ru(II) complexes: [PydimCl(2)RuL] (Pydim (1) pyridine-2,6-diimine; (2) L = NCMe; (3) L = PPh3) and [PydimCl(2)Ru(L-L)RuCl(2)Pydim] (4) L-L = pyrazine; (5) L-L = 4,4-bipyridine) have been synthesized from the corresponding (p-cymene)ruthenium dichloride dimer, pydim and ancillary ligands L and L-L, respectively. The Pydim-Ru(II) complexes have been employed as catalysts for the transfer hydrogenation of acetophenone in the presence of KOH using 2-propanol as a hydrogen source. Ligand substitution studies indicate that there is a significant difference in reactivity between complexes containing L/L-L and Pydim. Yields of up to 93% were obtained after 5 min at 82 degrees C. (C) 2007 Elsevier B.V. All rights reserved.
Anahtar Kelimeler : tridentate triamine ligands, pyridine-2, 6-diimines, Ru(II) complexes, transfer hydrogenation of acetophenone, article
Cilt: 271
Sayı: 01.Feb
ISSN: 1381-1169
Sınıflandırma :
8
Synthesis of novel rhodium-carbene complexes as efficient catalysts for addition of phenylboronic acid to aldehydes
Dergi Makalesi

Dergi Makalesi
Kaynak :
DSpace Makaleler
Yayıncı :
Journal of Molecular Catalysis A-Chemical
Yazar(lar) :
Ozdemir I , Demir S , Cetinkaya B
Konu :
N-heterocyclic carbene, rhodium complexes, imidazolidinylidine, arylation, aldehydes
Yıl :
2004
Journal of Molecular Catalysis A-Chemical
Yayıncı Web Sitesi
Kaydet
Rhodium(I)-carbene complexes with 1,3-dialkylimidazolidin-2-ylidine ligand were prepared and characterized by conventional spectroscopic methods and elemental analyses. The rhodium-carbene complexes RhCl(COD)(1,3-dialkyl-imidazolinylidene), 2a-d, are an active catalyst for addition of phenylboronic acid to aldehydes. (C) 2004 Elsevier B.V. All rights reserved.
Anahtar Kelimeler : N-heterocyclic carbene, rhodium complexes, imidazolidinylidine, arylation, aldehydes, article
Cilt: 215
Sayı: 01.Feb
ISSN: 1381-1169
Sınıflandırma :
9
Visible light photocatalytic reduction of Cr(VI) by surface modified CNT
Dergi Makalesi

Dergi Makalesi Open Access
Kaynak :
DSpace Makaleler
Yayıncı :
Journal of Molecular Catalysis A: Chemical
Yazar(lar) :
A. Mohamed , T. A. Osman , M. S. Toprak , M. Muhammed , E. Yilmaz , A. Uheida
Konu :
Chromium (VI), Composite nanofibers, Photocatalytic reduction, Visible light
Yıl :
2016
Journal of Molecular Catalysis A: Chemical
Yayıncı Web Sitesi Tam Metin
Kaydet
In this work we report a highly efficient photocatalytic reduction of Cr(VI) based on PAN-CNT/TiO2-NH2 composite nanofibers fabricated by using electrospinning technique followed by chemical crosslinking of surface modified TiO2 NPs functionalized with amino group. The structure and morphology of the fabricated composite nanofibers were characterized by FTIR, SEM, TEM, TGA, and XPS. The results indicate that the composite nanofibers possess excellent photoreduction performance for Cr(VI) under visible light (125 W) after 30 min, which is much faster than previous reports. The effects of various experimental parameters such as catalyst dose, irradiation time, initial concentration of Cr(VI), and pH on the photoreduction efficiency of Cr(VI) were investigated. The highest photoreduction efficiency of Cr (VI) was obtained at low acidity and low amount of TiO2/CNT photocatalyst. The kinetic experimental data was attained and fitted well with a pseudo-first-order model. The UV–vis spectrophotometer and XPS analyses proved that chromate Cr(VI) was reduced to Cr(III). In addition, it can be concluded that the addition of the phenol enhances the photocatalytic reduction of Cr(VI). Furthermore, the photoreduction mechanism has also been discussed. Finally, the fabricated composite nanofibers were found to be stable after at least five regeneration cycles. © 2016
DOI : 10.1016/j.molcata.2016.08.010
Anahtar Kelimeler : Chromium (VI), Composite nanofibers, Photocatalytic reduction, Visible light, Article
Cilt: 424
ISSN: 1381-1169
Sayfa: 45-53
Sınıflandırma :
Kimya %84
Kataliz %75
10
Syntheses and catalytic properties of alternating copolymers of poly4-maleimidopyridyl(p-cymene)dichloro Ru(II) with ?-methacryloxypropyl trimethoxysilane
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Dergi Makalesi
Kaynak 1:
DSpace Makaleler
Kaynak 2:
DSpace Makaleler
Yayıncı :
Journal of Molecular Catalysis A: Chemical
Yazar(lar) :
Özdemir I. , Çetinkaya B. , Seçkin T. , Köytepe S.
Konu :
Hydrosilylation, Metal complex catalyst, Poly(4-maleimidopyridine), Polyimide, Ru(II) catalyst
Yıl :
2002
Journal of Molecular Catalysis A: Chemical
Kaydet
A new monomer, 4-maleimidopyridyl(p-cymene)dichloro Ru(II), was synthesized by the reaction of maleic anhyride with p-dimethylaminopyridine(p-cymene)dichloro ruthenium(II). The homopolymer of maleimidopyridyl(p-cymene)dichloro Ru(II) and its copolymers with ?-methacryloxypropyl trimethoxysilane were prepared by radical polymerization with benzoyl peroxide as an initiator at 75°C. The structures of the synthesized monomer and polymers were identified by Fourier transform infrared, 1H NMR, and 13C NMR spectroscopies. Thermal behavior of the polymers were determined by differential thermal analysis, and thermogravimetric analysis, glass transition temperature was determined by differential scanning calorimeter. Excellent selectivities were observed by using Ru(II) complex as the catalyst in hydrosilylation reactions. The heterogeneous Ru(II) catalyst can also be recyled and reused without significant loss of selectivity or activity. © 2002 Elsevier Science B.V. All rights reserved.
Anahtar Kelimeler : Hydrosilylation, Metal complex catalyst, Poly(4-maleimidopyridine), Polyimide, Ru(II) catalyst, article
Cilt: 179
Sayı: 01.Feb
ISSN: 1381-1169
Sınıflandırma :
11
Synthesis of novel 1-alkylimidazoline and 1-alkylbenzimidazole palladium(II) complexes as efficient catalysts for Heck and Suzuki reactions involving arylchlorides
Dergi Makalesi

Dergi Makalesi
Kaynak :
DSpace Makaleler
Yayıncı :
Journal of Molecular Catalysis A-Chemical
Yazar(lar) :
Ozdemir I , Cetinkaya B , Demir S
Konu :
palladium, imidazolidine, benzimidazole, Suzuki, Heck
Yıl :
2004
Journal of Molecular Catalysis A-Chemical
Yayıncı Web Sitesi
Kaydet
Six palladium(II) complexes of the type [PdCl2(PR3)L], {PR3 = PPh3 or PPhMe2; L = 1-alkyl-2-imidazoline(1) or 1-alkylbenzimidazole(2)} have been prepared by reactions of [PdCl2(PR3)](2). The complexes were characterized by conventional spectroscopic methods and elemental analyses. The incorporation of N-coordinated imidazoline and benzimidazole complexes of palladium(II) gave high catalytic activity in the Suzuki coupling and Heck reaction of aryl bromides and deactivated aryl chloride substrates. (C) 2003 Elsevier B.V. All rights reserved.
Anahtar Kelimeler : palladium, imidazolidine, benzimidazole, Suzuki, Heck, article
Cilt: 208
Sayı: 01.Feb
ISSN: 1381-1169
Sınıflandırma :
12
Acidic sites in beta zeolites in dependence of the preparation methods
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Dergi Makalesi
Kaynak :
DSpace Makaleler
Yayıncı :
Journal of Molecular Catalysis A-Chemical
Yazar(lar) :
Dimitrova R , Gunduz G , Dimitrov L , Tsoncheva T , Yialmaz S , Urquieta-Gonzalez EA
Konu :
acid beta zeolites, mesostructured beta seeds, methanol conversion
Yıl :
2004
Journal of Molecular Catalysis A-Chemical
Yayıncı Web Sitesi
Kaydet
Beta zeolites synthesized by different methods are compared in their structure peculiarities and acidic properties by nitrogen physisorption, IR-KBr. pyridine sorption-desorption and thermoprogrammed desorption of ammonia. It is found that mesopores could be obtained in beta zeolites with the change of the activation procedure. Methanol conversion to dimethyl ether and hydrocarbons is used as a test reaction for understanding of the acid center function. (C) 2004 Elsevier B.V. All rights reserved.
Anahtar Kelimeler : acid beta zeolites, mesostructured beta seeds, methanol conversion, article
Cilt: 214
Sayı: 2
ISSN: 1381-1169
Sınıflandırma :
Kimya %100
Kataliz %91
13
Synthesis and catalytic properties of 1-alkylperimidineruthenium (II) complexes
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Dergi Makalesi
Kaynak 1:
DSpace Makaleler
Kaynak 2:
DSpace Makaleler
Yayıncı :
Journal of Molecular Catalysis A-Chemical
Yazar(lar) :
Alici B , Ozdemir I , Karaaslan K , Cetinkaya E , Cetinkaya B
Konu :
perimidine, olefin isomerization, ruthenium complexes, cycloisomerization
Yıl :
2005
Journal of Molecular Catalysis A-Chemical
Kaydet
Four new [RuCl2(perimidine)(p-cymene)] complexes have been prepared and characterized. Upon reaction with 1,1-diphenylprop-2-yn-1-ol they generate catalyst precursors. which perform the cycloisomerization of diallyltosylamide into N-tosyl-alpha-methylenepyrrolidine. (c) 2005 Elsevier B.V. All rights reserved.
Anahtar Kelimeler : perimidine, olefin isomerization, ruthenium complexes, cycloisomerization, article
Cilt: 231
Sayı: 01.Feb
ISSN: 1381-1169
Sınıflandırma :
14
Novel N-heterocyclic-carbene-rhodium complexes as hydrosilylation catalysts
Dergi Makalesi

Dergi Makalesi
Kaynak :
DSpace Makaleler
Yayıncı :
Journal of Molecular Catalysis A: Chemical
Yazar(lar) :
Yigit M. , Özdemir I. , Çetinkaya B. , Çetinkaya E.
Konu :
Hydrosilylation, Imidazolin-2-ylidene N-heterocyclic carbene, Perhydrobenzimidazolin-2-ylidene, Rhodium
Yıl :
2005
Journal of Molecular Catalysis A: Chemical
Yayıncı Web Sitesi
Kaydet
Novel rhodium-1,3-dialkylperhydrobenzimidazolin-2-ylidene (2a,b) and 1,3-dialkylimidazolin-2-ylidene complexes (4a,b) have been prepared and characterized by C, H, N analysis, 1H NMR and 13C NMR. Triethylsilane reacts with acetophenone derivatives in the presence of catalytic amount of the new rhodium(I)-carbene complexes, RhCl(COD)(1,3- dialkylperhydrobenzimidazolin-2-ylidene) or RhCl(COD)(1,3-dialkylimidazolin-2- ylidene) to give the corresponding silylethers in good yields (63-99%). © 2005 Elsevier B.V. All rights reserved.
Anahtar Kelimeler : Hydrosilylation, Imidazolin-2-ylidene N-heterocyclic carbene, Perhydrobenzimidazolin-2-ylidene, Rhodium, article
Cilt: 241
Sayı: 01.Feb
ISSN: 1381-1169
Sınıflandırma :
15
In situ generated 1-alkylbenzimidazole-palladium catalyst for the Suzuki coupling of aryl chlorides
Dergi Makalesi

Dergi Makalesi
Kaynak :
DSpace Makaleler
Yayıncı :
Journal of Molecular Catalysis A-Chemical
Yazar(lar) :
Ozdemir I , Sahin N , Gok Y , Demir S , Cetinkaya B
Konu :
palladium, benzimidazole ligands, C-C coupling, Suzuki reaction
Yıl :
2005
Journal of Molecular Catalysis A-Chemical
Yayıncı Web Sitesi
Kaydet
Six 1-alkylbenzimidazole have been prepared and characterized by conventional spectroscopic methods and elemental analyses. Novel in situ generated palladium-benzimidazole complexes, tested in the Suzuki coupling reaction between phenylboronic acid and several aryl chlorides showed excellent catalytic activity. (c) 2005 Elsevier B.V. All rights reserved.
Anahtar Kelimeler : palladium, benzimidazole ligands, C-C coupling, Suzuki reaction, article
Cilt: 234
Sayı: 01.Feb
ISSN: 1381-1169
Sınıflandırma :
16
Synthesis of novel palladium-carbene complexes as efficient catalysts for amination of aryl chlorides in ionic liquid
Dergi Makalesi

Dergi Makalesi
Kaynak :
DSpace Makaleler
Yayıncı :
Journal of Molecular Catalysis A: Chemical
Yazar(lar) :
Özdemir I. , Demir S. , Gök Y. , Çetinkaya E. , Çetinkaya B.
Konu :
Amination, Imidazolidinylidine, Ionic liquid, N-heterocyclic carbene, Palladium complexes
Yıl :
2004
Journal of Molecular Catalysis A: Chemical
Yayıncı Web Sitesi
Kaydet
The synthesis and characterization of [PdCl 2(N-heterocyclic carbene) 2] (2, 3), an air and moisture-stable complexes are reported. Amination of aryl halides in 1-methy-3-butyl-imidazolidinium tetrafluoroborate in the presence of palladium-carbene complexes as catalysts are described. Aryl chlorides undergo smooth nucleophilic substitution reactions with primary amines in ionic liquid to afford the corresponding arylamines in excellent yields under mild conditions. The synthesis and characterization of [PdCl 2(carbene) 2] complexes are reported and their used as catalysts for amination of aryl halides in ionic liquid. © 2004 Elsevier B.V. All rights reserved.
Anahtar Kelimeler : Amination, Imidazolidinylidine, Ionic liquid, N-heterocyclic carbene, Palladium complexes, article
Cilt: 222
Sayı: 01.Feb
ISSN: 1381-1169
Sınıflandırma :
17
In situ generated palladium catalysts bearing 1,3-dialkylperimidin-2-yline ligands for Suzuki reactions of aryl chlorides
Dergi Makalesi

Dergi Makalesi
Kaynak :
DSpace Makaleler
Yayıncı :
Journal of Molecular Catalysis A: Chemical
Yazar(lar) :
Özdemir I. , Alici B. , Gürbüz N. , Çetinkaya E. , Çetinkaya B.
Konu :
Aryl chloride, Cross-coupling, Dialkylperimidinium halide, N-heterocyclic carbene, Suzuki
Yıl :
2004
Journal of Molecular Catalysis A: Chemical
Yayıncı Web Sitesi
Kaydet
Four new 1,3-dialkylperimidinium halides have been prepared and characterized. The in situ prepared three component system Pd(OAc) 2/1,3-dialkylperimidinium (1a-d) and Cs2CO3 catalyses the Suzuki cross-coupling of deactivated aryl chloride substrates in excellent yields under mild conditions. © 2004 Elsevier B.V. All rights reserved.
Anahtar Kelimeler : Aryl chloride, Cross-coupling, Dialkylperimidinium halide, N-heterocyclic carbene, Suzuki, article
Cilt: 217
Sayı: 01.Feb
ISSN: 1381-1169
Sınıflandırma :
18
Hydrogenation of naphthalene and methylnaphthalene: modeling and spectroscopy
Dergi Makalesi

Dergi Makalesi Open Access
Kaynak :
DSpace Makaleler
Yayıncı :
Journal of Molecular Catalysis A: Chemical
Yazar(lar) :
Ş. Sayan , J. Paul
Konu :
Hydrotreatment, Methylnaphthalene, Modeling, Naphthalene, Catalysts, Desorption, Hydrogenation, Infrared radiation, Isomerization, Isomers, Ring degeneracy, Naphthalene, Aluminum derivative, Bicyclo compound, Naphthalene derivative, Nickel complex, Sulfide, Titanium, Titanium dioxide, Adsorption, Chemical structure, Energy, Infrared spectroscopy, Isomerism, Model, Molecular interaction, Vibration
Yıl :
2002
Journal of Molecular Catalysis A: Chemical
Yayıncı Web Sitesi Tam Metin
Kaydet
In situ infrared spectra of 1-methylnaphthalene (1-MeNapht)hydrogenation, over sulfided NiMo/Al2O3-TiO2 catalysts, were compared with theoretically derived properties of methylnaphthalene and its bicyclic products: MeDilin, MeTetralin, MeOctalin and MeDecalin, and with conversion data from literature. Comparisons were also made between the un-substituted and methyl-substituted two-rings, and between the 1- and 5-methyl isomers of 1,4-dihydronaphthalene (dilin) and 1,2,3,4-tetrahydronaphthalene (tetralin). IR spectra of MeNapht adsorption, on the sulfided catalyst, were matched with data for adsorption on the catalyst without sulfidation and the empty support. Surface bound MeNapht is observed below 250°C on all catalysts. MeNapht adsorption suppresses OH groups nondiscriminatory on the empty support and the metal loaded catalyst. We relate the results to previous data on the interaction between the supported metal sulfides and titanium modified aluminas. Calculated total energies, and experimentally derived heats of formation, pointed at decahydronaphthalene (decalin) as the dominant product of naphthalene hydrogenation, with tetralin as an abundant intermediate, and dilin and 1,2,3,4,5,6,7,8-octahydronaphthalene (octalin) as short lived transient stages. The spectroscopic modeling showed that the orbital fingerprints of the five bicyclic compounds were not distinctly different, nor more than marginally modified by methyl substitution or isomerization. The only significant difference came at the highest occupied orbital, where a high naphthalene density of states (DoS) overlapped with the valence bands of metal or metal sulfide catalysts. The vibrational bands for naphthalene, dilin, tetralin and octalin were well separated. Octalin and decalin, alone, have similar vibrational spectra. Upheaval of ring degeneracy for methyl-substituted two-ring structures broadened all infrared bands in a characteristic way.
DOI : 10.1016/S1381-1169(02)00033-X
Anahtar Kelimeler : Hydrotreatment, Methylnaphthalene, Modeling, Naphthalene, Catalysts, Desorption, Hydrogenation, Infrared radiation, Isomerization, Isomers, Ring degeneracy, Naphthalene, Aluminum derivative, Bicyclo compound, Naphthalene derivative, Nickel complex, Sulfide, Titanium, Titanium dioxide, Adsorption, Chemical structure, Energy, Infrared spectroscopy, Isomerism, Model, Molecular interaction, Vibration, Article
Cilt: 185
Sayı: 1-2
ISSN: 1381-1169
Sayfa: 211-222
Sınıflandırma :
19
Supporting ruthenium initiator on PolyHIPE
Konferans Makalesi

Konferans Makalesi
Kaynak :
DSpace Makaleler
Yayıncı :
Journal Of Molecular Catalysis A-Chemical
Yazar(lar) :
Sevil Cetinkaya , Ezat Khosravi , Richard Thompson
Konu :
PolyHIPE, supported catalyst, Grubbs initiator, Rutherford backscattering, supported ruthenium initiator
Yıl :
2006
Journal Of Molecular Catalysis A-Chemical
Yayıncı Web Sitesi
Kaydet
PolyHIPE samples were successfully synthesised using divinylbenzene and styrene as polymerisable continuous phase, aqueous phase containing potassium persulphate and calcium chloride dihydrate, a mixture of emulsifiers (SPAN20, CTAB and DDBSS) and toluene as a porogen. The PolyHIPE samples 1 and 2 and the PolyHIPE sample 3 were designed to be 90 and 92% porous, respectively, based on the aqueous phase content. PolyHIPE samples were found to be porous and open-cell microstructures with the surface area of 370-430 m(2) g(-1). Alkylidene exchange reactions were carried out between the double bonds of the PolyHIPE and the ruthenium initiator, Ru(=CHPh)(PCy3)(2)Cl-2, for the attachment of the initiator. The amount of initiator loading was determined by phosphorous analysis and for the first time by Rutherford backscattering (RBS) analysis. The loading of the initiator on the PolyHIPE samples, based on phosphorous analysis, was found to be 0.09-0.19 mmol/g. The RBS analysis showed the level of initiator loading to be 0.053-0.097 mmol/g. The level of initiator loading obtained from the phosphorous and the RBS analysis is higher than 0.035 mmol/g reported previously for ruthenium initiator supported on crosslinked polystyrene. However, the level of initiator loading obtained from RBS analysis is lower than that obtained from the phosphorous analysis by ICP-OES. The reason for this discrepancy is believed to be due to inaccuracy of phosphorous analysis as the result of the insolubility of the PolyHIPE supported initiator. (c) 2006 Elsevier B.V. All rights reserved.
DOI : 10.1016/j.molcata.2006.02.071
Anahtar Kelimeler : PolyHIPE, supported catalyst, Grubbs initiator, Rutherford backscattering, supported ruthenium initiator, conferenceObject
Cilt: 254
Sayı: 1-2
ISSN: 1381-1169
Sınıflandırma :
20
Improved palladium-catalyzed coupling reactions of aryl halides using saturated N-heterocarbene ligands
Dergi Makalesi

Dergi Makalesi
Kaynak :
DSpace Makaleler
Yayıncı :
Journal of Molecular Catalysis A-Chemical
Yazar(lar) :
Gurbuz N , Ozdemir I , Demir S , Cetinkaya B
Konu :
palladium, imidazolidin-2-ylidene, aryl halides, phenylboronic acid, Suzuki, styrene, Heck
Yıl :
2004
Journal of Molecular Catalysis A-Chemical
Yayıncı Web Sitesi
Kaydet
The incorporation of saturated N-heterocyclic carbenes into palladium pre-catalysts gives high catalyst activity in the Suzuki coupling of aryl iodides, bromides and deactivated aryl chloride substrates, whereas the yield of the palladium catalyzed Heck reaction of deactivated aryl chlorides is negligible. The complexes were generated in the presence of Pd(OAc)(2) by in situ deprotonation of 1,3-dialkylimidazolinium salts LHX (1) which were characterized by conventional spectroscopic methods and elemental analyses. (C) 2003 Elsevier B.V. All rights reserved.
Anahtar Kelimeler : palladium, imidazolidin-2-ylidene, aryl halides, phenylboronic acid, Suzuki, styrene, Heck, article
Cilt: 209
Sayı: 01.Feb
ISSN: 1381-1169
Sınıflandırma :
21
Carboxymethyl chitosan schiff base supported heterogeneous palladium(II) catalysts for suzuki cross-coupling reaction
Dergi Makalesi

Dergi Makalesi Open Access
Kaynak :
DSpace Makaleler
Yayıncı :
Journal of Molecular Catalysis A: Chemical
Yazar(lar) :
Talat Baran , Eda Açıksöz , Ayfer Menteş
Konu :
Biopolymer-Supported Catalyst, O-Carboxymethyl Chitosan, Schiff Base, Suzuki, Reusable Catalyst
Yıl :
2015
Journal of Molecular Catalysis A: Chemical
Yayıncı Web Sitesi Tam Metin
Kaydet
In this study, two new O-carboxymethyl chitosan Schiff bases supported Pd(II) catalyst were synthesized (OCMCS-3aPd and OCMCS-4aPd). The catalysts were characterized with FTIR, TG/DTG, SEM/EDAX, XRD, ICP-OES, UV vis, magnetic moment and molar conductivity. The catalytic activities of these catalysts were tested in the synthesis of biaryl compounds by Suzuki cross-coupling reactions. Characterizations of the biaryls were performed with GC MS and H-1 NMR. In synthesis of the biaryl compounds in the presence of the Pd(II) catalyst, high selectivity was observed; no homo-coupling byproducts were detected in the spectra. A reusability test demonstrated that the catalysts were highly efficient even after ten run. The mercury poisoning and leaching tests indicated that the catalysts have heterogeneous nature.
Anahtar Kelimeler : Biopolymer-Supported Catalyst, O-Carboxymethyl Chitosan, Schiff Base, Suzuki, Reusable Catalyst, article
Cilt: 407
ISSN: 1381-1169
Sınıflandırma :
22
A comparative study on the structural and catalytic properties of zeolites type ZSM-5, mordenite, Beta and MCM-41
Dergi Makalesi

Dergi Makalesi
Kaynak :
DSpace Makaleler
Yayıncı :
Journal of Molecular Catalysis A-Chemical
Yazar(lar) :
Dimitrova R , Gunduz G , Spassova M
Konu :
zeolites, mesopores, alpha-pinene isomerization, methanol conversion
Yıl :
2006
Journal of Molecular Catalysis A-Chemical
Yayıncı Web Sitesi
Kaydet
Zeolites of different structures and textural mesoporosity (ZSM-5, mordenite, Beta and MCM-41) were investigated as catalysts in liquid phase isomerization of alpha-pinene at 373 K and in methanol conversion. The morphological characterization of the samples was fulfilled before and after the reaction by XRD, SEM, BET and temperature programmed desorption of ammonia. (c) 2005 Elsevier B.V. All rights reserved.
Anahtar Kelimeler : zeolites, mesopores, alpha-pinene isomerization, methanol conversion, article
Cilt: 243
Sayı: 1
ISSN: 1381-1169
Sınıflandırma :
Kimya %100
Kataliz %99
23
Testing catalytic activity of ruthenium(III) acetylacetonate in the presence of trialkylphosphite or trialkylphosphine in hydrogen generation from the hydrolysis of sodium borohydride
Araştırma Makalesi

Araştırma Makalesi Open Access
Kaynak :
Aperta - TÜBİTAK Açık Arşivi
Yayıncı :
JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL
Yazar(lar) :
Saim Ozkar , Tuelin Demiralp , Mehdi Masjedi
Yıl :
2009
JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL
Yayıncı Web Sitesi Piri Tam Metin Bulucu
Kaydet
Catalytic activity of Ru(acac)(3) in the presence of different phosphorus compounds (P(OMe)(3), P(OPh)(3), PPh3 and dppe) was investigated for the first time in the hydrolysis of NaBH4. Phosphorus compound, usually known as poison in catalysis, is involved in the formation of a species which has higher catalytic activity in comparison with Ru(aCaC)(3) alone. Varying the phosphorus compound affects the catalytic activity and lifetime of the catalyst as well as the kinetics and the activation parameters of the hydrolysis of NaBH4. For all of the phosphorus compounds, the hydrogen generation was found to be zero-order with respect to the substrate concentration and first-order regarding the catalyst concentration. The catalyst system with P(OMe)3 shows the highest catalytic activity and provides the largest total turnover number (TTON = 20,700 over 72 h) in the hydrolysis of NaBH4. The highest activation energy and enthalpy values were obtained for the catalyst with dppe (E-a = 59 +/- 2. Delta H-# = 60 +/- 2 kJ/mol) while the lowest values were found for the catalyst system with PPh3 (E-a = 46 +/- 2, Delta H-# = 43 +/- 1 kJ/mol). (C) 2009 Elsevier B.V. All rights reserved.
DOI : 10.1016/j.molcata.2009.05.022
Sayi :310
issue :1-2
Sayfa :59-63
Sınıflandırma :
24
Palladium(0) nanoclusters stabilized by poly(4-styrenesulfonic acid-co-maleic acid) as an effective catalyst for Suzuki-Miyaura cross-coupling reactions in water
Araştırma Makalesi

Araştırma Makalesi Open Access
Kaynak :
Aperta - TÜBİTAK Açık Arşivi
Yayıncı :
JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL
Yazar(lar) :
Saim Ozkar , Murat Aydemir , Feyyaz Durap , Onder Metin
Yıl :
2011
JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL
Yayıncı Web Sitesi Piri Tam Metin Bulucu
Kaydet
Palladium(0) nanoclusters stabilized by poly(4-styrenesulfonic acid-co-maleic acid), PSSA-co-MA, were generated in situ during the hydrolysis of ammonia-borane (AB) from the reduction of potassium tetrachloropalladate(II) in aqueous solution at room temperature. They were isolated from the reaction solution and characterized by UV-visible electronic absorption spectroscopy, TEM, SAED and XRD techniques. The PSSA-co-MA stabilized palladium(0) nanoclusters were used as catalyst in Suzuki-Miyaura cross-coupling reactions of various of arylbromides or aryl iodide with phenylboronic acid in water without any purification process after catalytic hydrolysis of AB. They show excellent catalytic activity in coupling of series of aryl bromides or aryl iodide with phenylboronic acid under the optimized reaction conditions in water. PSSA-co-MA stabilized palladium(0) nanoclusters provided turnover frequency of 1980 and 5940h(-1) in Suzuki-Miyaura coupling reactions of phenylboronic acid with p-bromoacetophenone or p-iodobenzene, respectively, which are the highest values ever reported for the Suzuki-Miyaura coupling reactions in water as sole solvent. (C) 2011 Elsevier B.V. All rights reserved.
DOI : 10.1016/j.molcata.2011.01.011
Sayi :337
issue :1-2
Sayfa :39-44
Sınıflandırma :
25
A skeletal rearrangement study of a carbon-13 labelled 3-methylpentane on doped sulphated zirconia catalysts
Araştırma Makalesi

Araştırma Makalesi Open Access
Kaynak :
Aperta - TÜBİTAK Açık Arşivi
Yayıncı :
JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL
Yazar(lar) :
Francois Garin , Umit Bilge Demirci
Yıl :
2006
JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL
Yayıncı Web Sitesi Piri Tam Metin Bulucu
Kaydet
The isomerization on sulphated zirconias of the 3-methyl(3-(13)C)pentane, molecule chosen to distinguish between the methyl and ethyl migrations, is studied.
DOI : 10.1016/j.molcata.2006.05.023
Sayi :258
issue :1-2
Sayfa :46-58
Sınıflandırma :
26
Investigation of ruthenium-copper bimetallic catalysts for direct epoxidation of propylene: A DFT study
Araştırma Makalesi

Araştırma Makalesi Open Access
Kaynak :
Aperta - TÜBİTAK Açık Arşivi
Yayıncı :
JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL
Yazar(lar) :
Isik Onal , Selim Senkan , Ali Can Kizilkaya
Yıl :
2010
JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL
Yayıncı Web Sitesi Piri Tam Metin Bulucu
Kaydet
Propylene epoxidation reactions are carried out on Ru-Cu(1 1 1) and Cu(1 1 1) surfaces with periodic density functional theory (DFT) calculations. Ru-Cu(1 1 1) surface is modeled as Cu(1 1 1) monolayer totally covering the Ru(0 0 0 1) surface underneath, in accordance with the literature. It is shown that the Ru-Cu(1 1 1) surface is ineffective for propylene oxide formation since it has a lower energy barrier (0.48 eV) for the stripping of the allylic hydrogen of propylene and a higher energy barrier (0.92 eV) towards oxametallacycle formation compared to Cu(1 1 1) surface which has a barrier of 0.83 eV for hydrogen stripping and 0.75 eV for oxametallacycle formation. The reason behind this ineffectiveness is shown to be the higher basicity of the atomic oxygen adsorbed on Ru-Cu(111) compared to Cu(1 11), evaluated by the adsorption of sulfur dioxide onto the systems. The results are consistent both with recent publications about propylene epoxidation and previous studies performed about the structure of Ru-Cu catalysts. (C) 2010 Elsevier B.V. All rights reserved.
DOI : 10.1016/j.molcata.2010.07.008
Sayi :330
issue :1-2
Sayfa :107-111
Sınıflandırma :
27
Novel homogeneous catalyst comprising ruthenium and trimethylphosphite for the hydrolysis of sodium borohydride
Araştırma Makalesi

Araştırma Makalesi Open Access
Kaynak :
Aperta - TÜBİTAK Açık Arşivi
Yayıncı :
JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL
Yazar(lar) :
Saim Ozkar , Leyla Tatar Yildirim , Mehdi Masjedi
Yıl :
2012
JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL
Yayıncı Web Sitesi Piri Tam Metin Bulucu
Kaydet
Homogeneous catalytic hydrolysis of sodium borohydride starting with Ru(acac)(3) (acac = acetylacetonate) and P(OMe)(3) was followed by monitoring the hydrogen evolution and the UV-vis electronic absorption spectra which shows the conversion of all ruthenium(III) to a ruthenium(II) species, most likely acting as catalyst. This active catalyst is alive only under reducing conditions and converted mainly to Ru(acac)(3) along with other minor complexes when the catalytic reaction is over. A ruthenium(II) complex was isolated from the reaction solution after the complete catalytic hydrolysis of sodium borohydride and characterized to be [Ru{P(OMe)(3)}(4)H-2] by single crystal XRD, MS. UV-vis, FTIR, H-1, C-13 and P-31 NMR spectroscopy. [Ru{P(OMe)(3)}(4)H-2] complex crystallizes in the triclinic space group P-1 with a = 10.066(2)angstrom, b = 19.108(3)angstrom, c = 20.938(4)angstrom, alpha = 78.839(14)degrees, beta = 87.308(16)degrees and gamma = 79.506(14)degrees. This ruthenium(II) complex was found not to be the active catalyst in the hydrolysis of sodium borohydride, rather one of its conversion products after catalysis. Although the active catalyst could not be isolated from the reaction solution, it could be stabilized by adding chelating 2,2-bipyridine into the solution during the catalysis. Thus, a stabilized form of the active catalyst, [Ru(acac)(bipy){P(OMe)(3)}H], could be isolated and characterized by MS, UV-vis, FTIR, H-1, C-13 and P-31 NMR spectroscopy. [Ru(acac)(bipy){P(OMe)(3)}H] is expectedly not as active as the ruthenium(II) species formed in situ during the catalysis. Taking all the results together reveals that the active catalyst is a ruthenium(II) complex, either [Ru(acac){P(OMe)(3)}(3)H] or most likely its dissociation product, [Ru(acac){P(OMe)(3)}(2)H]. Control experiments showed that 2,2-bipyridine can replace only the trimethylphosphite ligands but not the acetylacetonato ligand in the ruthenium(II) complex. (C) 2011 Elsevier B.V. All rights reserved.
DOI : 10.1016/j.molcata.2011.12.015
Sayi :355
Sayfa :186-191
Sınıflandırma :
28
Graphene-supported NiPd alloy nanoparticles: A novel and highly efficient heterogeneous catalyst system for the reductive amination of aldehydes
Araştırma Makalesi

Araştırma Makalesi Open Access
Kaynak :
Aperta - TÜBİTAK Açık Arşivi
Yayıncı :
JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL
Yazar(lar) :
Bela Toeroek , Arif Dastan , Onder Metin , Khadijeh Ganjehyan , Bilal Nisanci
Yıl :
2015
JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL
Yayıncı Web Sitesi Piri Tam Metin Bulucu
Kaydet
A novel and highly efficient heterogeneous catalytic reductive amination of aldehydes is described. The recently developed graphene supported NiPd alloy nanoparticle (G-NiPd) catalyst using ammonia borane (AB) as a green, stable and safe hydrogen donor was used in a water/methanol mixture (v/v=2/3) under ambient conditions. The catalytic system was successfully applied in the reductive amination of various substituted aldehydes with amines and the corresponding products were obtained in (up to) 99% yield in 6 h. The G-NiPd catalyst could be recycled up to five times without any significant loss in the product yield. (C) 2015 Elsevier B.V. All rights reserved.
DOI : 10.1016/j.molcata.2015.08.022
Sayi :409
Sayfa :191-197
Sınıflandırma :
Kimya %100
Kataliz %97

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