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molybdenum-compounds
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Intermolecular C-H⋯O and n → π∗ and short intramolecular σ → π∗ interactions in the molybdenum(0) tetracarbonyl complex of a very twisted 14-membered tetraazaannulene macrocyclic ligand: Structural and computational studies
, Article CrystEngComm ; Volume 21, Issue 35 , 2019 , Pages 5222-5226 ; 14668033 (ISSN) ; Hosseini, M ; Abdolrahimi, A ; Mahmoudi, M ; Sharif University of Technology
Royal Society of Chemistry
2019
Abstract
The structural and computational studies of a new molybdenum tetracarbonyl complex of 5,14-dihydro-6,17-dimethyl-8,15-diphenyldibenzo[b,i]-[1,4,8,11]tetraazacyclotetradecine, a 14-membered tetraazaannulene macrocyclic ligand, Me2Ph2H2TAA, were carried out by X-ray crystallography and density functional and natural bond orbital (NBO) theories. The complex showed an interesting intermolecular C-H⋯O hydrogen bond which was supported by n → π∗ interaction, forming a one-dimensional extended chain along the b-axis. Interesting intramolecular C-H⋯π and very short σ → π∗ (C-H⋯CO) interactions stabilized the twisted geometry of the coordinated ligand. © 2019 The Royal Society of Chemistry 2019
Intermolecular C-H⋯O and n → π∗ and short intramolecular σ → π∗ interactions in the molybdenum(0) tetracarbonyl complex of a very twisted 14-membered tetraazaannulene macrocyclic ligand: Structural and computational studies
, Article CrystEngComm ; Volume 21, Issue 35 , 2019 , Pages 5222-5226 ; 14668033 (ISSN) ; Hosseini, M ; Abdolrahimi, A ; Mahmoudi, M ; Sharif University of Technology
Royal Society of Chemistry
2019
Abstract
The structural and computational studies of a new molybdenum tetracarbonyl complex of 5,14-dihydro-6,17-dimethyl-8,15-diphenyldibenzo[b,i]-[1,4,8,11]tetraazacyclotetradecine, a 14-membered tetraazaannulene macrocyclic ligand, Me2Ph2H2TAA, were carried out by X-ray crystallography and density functional and natural bond orbital (NBO) theories. The complex showed an interesting intermolecular C-H⋯O hydrogen bond which was supported by n → π∗ interaction, forming a one-dimensional extended chain along the b-axis. Interesting intramolecular C-H⋯π and very short σ → π∗ (C-H⋯CO) interactions stabilized the twisted geometry of the coordinated ligand. © 2019 The Royal Society of Chemistry 2019
Direct extraction of Mo(VI) from sulfate solution by synergistic extractants in the rotation column
, Article Chinese Journal of Chemical Engineering ; Volume 28, Issue 2 , 2020 , Pages 445-455 ; Torab Mostaedi, M ; Outokesh, M ; Asadollahzadeh, M ; Sharif University of Technology
Chemical Industry Press
2020
Abstract
Direct extraction of molybdenum from sulfate solution with synergistic extractants (mixture of D2EHPA and TBP) was studied in the rotation column. The influence of extractant concentration and initial pH of aqueous phase was studied in the bench scale experiments. The outcomes demonstrated that the synergistic solvent extraction enhances the constancy of the extracted complexes for transfer into the organic phase. In the continuous experiments, the effect of different operating parameters such as speed of agitation, inlet solvent flow rate and inlet aqueous flow rate on the holdup, mean drop size, drop size distribution, slip and characteristic velocities and extraction percentage were...
Separation of rhenium and molybdenum from molybdenite leach liquor by the solvent extraction method
, Article Minerals and Metallurgical Processing ; Volume 30, Issue 1 , February , 2013 , Pages 53-58 ; 07479182 (ISSN) ; Yoozbashizadeh, H ; Mohammadi, M ; Abazarpoor, A ; Maarefvand, M ; Sharif University of Technology
2013
Abstract
Molybdenum resources around the world are mainly associated with porphyry copper ores. Molybdenite (MoS2) is the main Mo mineral that has rhenium in its crystal lattice. This paper investigates the recovery of rhenium and molybdenum from a molybdenite concentrate using a hydrometallurgical treatment method. The molybdenite concentrate is leached with nitric acid and subjected to solvent extraction to recover and separate rhenium and molybdenum from the leached liquor. The effects of pH and the chemicals' concentration on extraction characteristics of Mo and Re are investigated to define the best condition for selective extraction of these metals. The tested leached liquor contained of 8.2...
Molybdenum oxo-peroxo complex: A very fast catalyst for oxidation and reduction of sulfur-based compounds
, Article Catalysis Communications ; Volume 23 , June , 2012 , Pages 14-19 ; 15667367 (ISSN) ; Haghdoost, M. M ; Amini, M ; Derakhshandeh, P. G ; Sharif University of Technology
2012
Abstract
We have evaluated the catalytic activity of a molybdenum(VI) oxo-peroxo complex through the oxidation and reduction of sulfur-based compounds. Arylalkyl, diaryl and dialkyl sulfides are selectively oxidized to corresponding sulfoxides, with tert-butyl hydroperoxide (TBHP), in the presence of MoO(O 2)(phox) 2 complex as catalyst. This molybdenum complex was also found to be an efficient catalyst for the deoxygenation of sulfoxides to sulfides with PPh 3 in excellent yields and chemoselectivity
In situ and simultaneous synthesis of a novel graphene-based catalyst for deep hydrodesulfurization of naphtha
, Article Catalysis Letters ; Volume 145, Issue 9 , September , 2015 , Pages 1660-1672 ; 1011372X (ISSN) ; Kazemeini, M ; Rashidi, A ; Bazmi, M ; Sharif University of Technology
Kluwer Academic Publishers
2015
Abstract
In this research, a novel graphene-supported catalyst was prepared through which, a simultaneous chemical exfoliation of graphite and MoS2 powder performed preparing a new composite species and evaluated for the hydrodesulfurization reaction of naphtha and no sulfidation pretreatment was performed upon the catalyst. Also, the influences of the operating parameters such as temperature, and liquid hourly space velocity on HDS conversion evaluated. (Chemical Equation Presented)
Fabrication and surface stochastic analysis of enhanced photoelectrochemical activity of a tuneable MoS2-CdS thin film heterojunction
, Article RSC Advances ; Volume 6, Issue 20 , 2016 , Pages 16711-16719 ; 20462069 (ISSN) ; Ebrahimi, M ; Zhao, M ; Moradlou, O ; Samadi, M ; Bayat, A ; Zhang, H. L ; Moshfegh, A. Z ; Sharif University of Technology
Royal Society of Chemistry
2016
Abstract
A very simple and well-controlled procedure was employed to prepare CdS nanoparticle/few-layer MoS2 nanosheet/Indium tin oxide (ITO) thin film heterostructures. To tune and fabricate the CdS/MoS2(t)/ITO thin films with various surface topographies, first electrophoretic deposition (EPD) was used to deposit MoS2 nanosheets on the ITO substrate under an optimized applied potential difference (8 V) for different deposition times (t) of 30, 60, 120 and 240 s. Then, CdS nanoparticles were deposited via a successive ion layer adsorption and reaction (SILAR) technique. The highest photo-current density of 285 μA cm-2 was measured for the CdS/MoS2(60 s)/ITO sample, which was about 2.3 times higher...
Significant enhancement in the efficiency of photoconductive antennas using a hybrid graphene molybdenum disulphide structure
, Article Journal of Nanophotonics ; Volume 10, Issue 3 , 2016 ; 19342608 (ISSN) ; Safian, R ; Sharif University of Technology
SPIE
2016
Abstract
We propose a hybrid graphene molybdenum disulphide-based photoconductive antenna to overcome the restrictions of metallic photoconductive antennas and graphene-based photoconductive antennas, simultaneously. The structure is composed of a hybrid graphene-MoS2 strip as the antenna deposited on a low-temperature gallium arsenide substrate. A full-wave electromagnetic solver, namely, high frequency structural simulator (HFSS) is used to analyze the whole structure. It is shown that the proposed photoconductive antenna provides us with not only high input impedance and reconfigurability but also high values of matching efficiency and radiation efficiency. The impact of increasing MoS2 layers on...
Improving tribological behavior of friction stir processed A413/SiCp surface composite using MoS2 lubricant particles
, Article Transactions of Nonferrous Metals Society of China (English Edition) ; Volume 27, Issue 2 , 2017 , Pages 298-304 ; 10036326 (ISSN) ; Shamanian, M ; Sadeghian, M ; Sepehrinia, P ; Sharif University of Technology
Nonferrous Metals Society of China
2017
Abstract
The effect of MoS2 lubricant particles on the microstructure, microhardness and tribological behavior of A413/SiCp surface composite, fabricated via friction stir processing (FSP), was studied. For this purpose, the FSP was carried out with tool rotational speed of 1600 r/min, tool travel speed of 25 mm/min and tool tilt angle of 3° through only a “single pass”. The optical and scanning electron microscopies, microhardness and reciprocating wear tests were used to characterize the samples. The results showed that the addition of MoS2 lubricant particles to A413/SiCp surface composite leads to the decrease of friction coefficient and mass loss. In fact, the generation of mechanically mixed...
MoS2 quantum-dots as a label-free fluorescent nanoprobe for the highly selective detection of methyl parathion pesticide
, Article Analytical Methods ; Volume 9, Issue 4 , 2017 , Pages 716-723 ; 17599660 (ISSN) ; Rashti, A ; Hormozi Nezhad, M. R ; Mahdavi, V ; Sharif University of Technology
Royal Society of Chemistry
2017
Abstract
A reliable, simple, and sensitive fluorescence method was developed for the determination of methyl parathion (MP) in rice using MoS2 quantum dots (QDs). Rapid hydrolysis of MP under alkaline conditions, and thus the formation of p-nitrophenol (p-NP) can be used for MP detection. The functional mechanism of the nanoprobe relies on p-nitrophenol-induced photoluminescence quenching of MoS2 QDs. The high probability of resonance energy transfer (RET) stems from the spectral overlap of MoS2 QD emission spectra and the absorption spectra of p-NP. The high value of the Stern-Volmer constant (KSV = 3.73 × 104 M-1) suggests the efficient quenching of MoS2 QDs by MP in the course of the ET process....
Heterogeneous SBA-15-supported oxoperoxomolybdenum(VI) complex for enhanced olefin epoxidation
, Article Catalysis Communications ; Volume 88 , 2017 , Pages 9-12 ; 15667367 (ISSN) ; Moradi Shoeili, Z ; Ashouri, F ; Bagherzadeh, M ; Sharif University of Technology
Abstract
Heterogeneous nanoscale catalyst was successfully synthesized via anchoring of oxoperoxo molybdenum(VI) complex on the chloro-functionalized SBA-15. The mesoporous nanomaterials, MoO3(sal-phz)/SBA-15 (where sal-phz is salicylidene 2-picoloyl hydrazine) were identified by several characterization techniques. MoO3(sal-phz)/SBA-15 and MoO3(sal-phz) were also treated as catalysts in the olefins epoxidation reactions. Both homogenous and heterogeneous catalysts exhibit outstanding activity and selectivity for epoxide with tert-BuOOH in decane as oxidant at 95 °C. In addition, the heterogeneous nanocatalyst was chemically stable and can be efficiently reused for at least six cycles without a...
Oxazine containing molybdenum(VI)–oxodiperoxo complex immobilized on SBA-15 as highly active and selective catalyst in the oxidation of alkenes to epoxides under solvent-free conditions
, Article Microporous and Mesoporous Materials ; Volume 251 , 2017 , Pages 173-180 ; 13871811 (ISSN) ; Moradi Shoeili, Z ; Esmailpour, P ; Akbayrak, S ; Özkar, S ; Sharif University of Technology
Elsevier B.V
2017
Abstract
Molybdenum(VI)–oxodiperoxo complex containing an oxazine ligand, ([MoO(O2)2(phox)], phox: 2-(2′-hydroxyphenyl)-5,6-dihydro-1,3-oxazine) was conveniently synthesized and immobilized onto chloro-functionalized mesoporous silica SBA-15 by covalent bonding between the chloropropyl group on the internal surface of the pores and the nitrogen atom of oxazine ligand yielding [MoO(O2)2(phox)]/SBA-15. The resulting material was characterized by FT-IR, TGA, XRD, SEM, TEM, EDX, ICP-AES, BET and UV–vis spectroscopy. The heterogeneous catalyst [MoO(O2)2(phox)]/SBA-15 was employed in the epoxidation of alkenes, exhibiting high catalytic performance and selectivity for epoxide similar to that of homogeneous...
Extraction of molybdenum (VI) and vanadium (V) from nitrate solutions using coupling of acid and solvating extractants
, Article International Journal of Engineering, Transactions A: Basics ; Volume 32, Issue 10 , 2019 , Pages 1366-1371 ; 17281431 (ISSN) ; Torab Mostaedi, M ; Outokesh, M ; Asadollahzadeh, M ; Sharif University of Technology
Materials and Energy Research Center
2019
Abstract
In this study, solvent extraction method has been utilized for separation of molybdenum and vanadium from nitrate solution by utilizing coupling of acid and solvating extractants (D2EHPA and TBP extractants). The outcomes demonstrated that synergistic solvent extraction improves stability of formatted complexes for transfer to the organic phase. The main parameters such as pH value, concentration of extractants, NH4OH concentration as the stripping agent and contact time were optimized at 0.4, 15% (v/v) D2EHPA, 10% (v/v) TBP, 2 M and 30 min, respectively. The maximum separation factor of 24.84 was obtained with a new synergistic mixture of D2EHPA and TBP diluted with kerosene. According to...
Mass transfer coefficients of extracting Mo (VI) and W (VI) in a stirred tank by solvent extraction using mixture of Cyanex272 and D2EHPA
, Article Separation Science and Technology (Philadelphia) ; 2019 ; 01496395 (ISSN) ; Torab Mostaedi, M ; Outokesh, M ; Asadollahzadeh, M ; Sharif University of Technology
Taylor and Francis Inc
2019
Abstract
In this study, the mass transfer evaluation of an agitated liquid-liquid system for the extraction of molybdenum and tungsten from aqueous sulfate solution was investigated. It was found from batch experiments for separation of molybdenum from tungsten that the initial aqueous pH, Cyanex272 and D2EHPA concentration, contact time, dispersed phase volume fraction and impeller speed were optimized at 1.3, 0.07 M, 0.29 M, 15 min, 0.09 and 280 rpm, respectively. The results indicate that a suitable composition for stripping is 1.5 M NH4OH and 0.6 M NH4F. Furthermore, a modified correlation based on dimensionless numbers was derived for the prediction of continuous phase mass transfer in the...
Microstructure and mechanical properties of dissimilar nickel-based superalloys resistance spot welds
, Article Materials Science and Engineering A ; Volume 773 , 2020 ; Pouranvari, M ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
This paper addresses the factors affecting the mechanical properties of dissimilar resistance spot welds between Nimonic 263 and Hastelloy X nickel-based superalloys. The fusion zone (FZ) of the dissimilar weld displayed higher hardness values compared to the base metals which can be attributed to (i) the formation of Mo-rich carbide in the interdendritic zone due to positive segregation behavior of Mo and C during non-equilibrium solidification of the weld, (ii) the enhanced solid solution strengthening due to mixing of the base metals, and (iii) the formation of ultra-fine dendritic structure in the FZ due to ultra-fast cooling rate of the resistance spot welding. Formation of...
Resistance spot welding of Nimonic 263 nickel-based superalloy: microstructure and mechanical properties
, Article Science and Technology of Welding and Joining ; Volume 25, Issue 1 , 2020 , Pages 28-36 ; Pouranvari, M ; Sharif University of Technology
Taylor and Francis Ltd
2020
Abstract
This paper addresses the metallurgical and mechanical response of Nimonic 263 nickel-based superalloy to resistance spot welding. Solidification structure of the fusion zone is described in terms of dendrite arm spacing, segregation behaviour and secondary carbide formation in the inter-dendritic area. The heat affected zone is featured by negligible grain growth and constitutional liquation of primary (Ti, Mo)C carbide present in the initial microstructure of the base metal. Mechanical behaviour of the welds was characterised by interfacial to pullout failure mode transition, peak load and energy absorption of the joints during the tensile-shear loading. The fusion zone size and the...
Mass transfer coefficients of extracting Mo (VI) and W (VI) in a stirred tank by solvent extraction using mixture of Cyanex272 and D2EHPA
, Article Separation Science and Technology (Philadelphia) ; Volume 55, Issue 17 , 2020 , Pages 3140-3150 ; Torab Mostaedi, M ; Outokesh, M ; Asadollahzadeh, M ; Sharif University of Technology
Bellwether Publishing, Ltd
2020
Abstract
In this study, the mass transfer evaluation of an agitated liquid-liquid system for the extraction of molybdenum and tungsten from aqueous sulfate solution was investigated. It was found from batch experiments for separation of molybdenum from tungsten that the initial aqueous pH, Cyanex272 and D2EHPA concentration, contact time, dispersed phase volume fraction and impeller speed were optimized at 1.3, 0.07 M, 0.29 M, 15 min, 0.09 and 280 rpm, respectively. The results indicate that a suitable composition for stripping is 1.5 M NH4OH and 0.6 M NH4F. Furthermore, a modified correlation based on dimensionless numbers was derived for the prediction of continuous phase mass transfer in the...
Immobilization of dioxomolybdenum(VI) complex bearing salicylidene 2-picoloyl hydrazone on chloropropyl functionalized SBA-15: A highly active, selective and reusable catalyst in olefin epoxidation
, Article Applied Catalysis A: General ; Vol. 475 , April , 2014 , pp. 55-62 ; ISSN: 0926860X ; Zare, M ; Salemnoush, T ; Ozkar, S ; Akbayrak, S ; Sharif University of Technology
Abstract
A novel organic-inorganic hybrid heterogeneous catalyst system was obtained from the reaction of the molybdenum(VI) complex of salicylidene 2-picoloyl hydrazone with mesoporous silica containing 3-chloropropyl groups prepared by a direct synthetic approach involving hydrolysis and co-condensation of tetraethylorthosilicate (TEOS) and 3-chloropropyltrimethoxysilane in the presence of the triblock copolymer P123 as template under acidic conditions. Characterization of the functionalized materials by X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), N2 adsorption/desorption, FT-IR and UV-Vis spectroscopy, and thermogravimetric...
Wear and corrosion properties of electroless nickel composite coatings with PTFE and/or MoS 2 particles
, Article Journal of Coatings Technology Research ; Volume 8, Issue 4 , 2011 , Pages 527-533 ; 15470091 (ISSN) ; Ghorbani, M ; Sharif University of Technology
2011
Abstract
This study focuses on the effect of co-deposition of PTFE and/or MoS 2 particles on the morphology, wear, and corrosion properties of electroless nickel coating. The composite coating of EN-PTFE-MoS 2 was heat treated at different temperatures for hardness investigations. The surface morphology of coatings was characterized by scanning electron microscopy. Pin-on-disk and potentiodynamic polarization tests were used to study the tribological and corrosion properties of the coatings, respectively. Results of hardness analysis revealed that the hardness of electroless nickel coatings was increased by the heat treatment, and its maximum was gained at 400°C. Wear investigations showed that...
Mo(vi) complex supported on Fe3 O4 nanoparticles: magnetically separable nanocatalysts for selective oxidation of sulfides to sulfoxides
,
Article
RSC Advances
;
Volume 5, Issue 66
,
Jun
,
2015
,
Pages 53349-53356
;
20462069 (ISSN)
; Balali, M
; Haghdoost, M. M
; Bagherzadeh, M
;
Sharif University of Technology
Royal Society of Chemistry
2015
Abstract
A molybdenum complex, [MoO2 Cl2 (DMSO)2 ], was immobilized on amino propyl and Schiff base modified magnetic Fe3 O4 @SiO2 nanoparticles by covalent linkage. The resulting nanoparticles were used as efficient and recyclable catalysts for the selective oxidation of sulfides to sulfoxides using urea hydrogen peroxide as the oxidant. The complete characterization of catalysts was carried out by means of thermogravimetric analysis (TGA), scanning electron microscopy (SEM), transmission electron microscopy (TEM), vibrating sample magnetometry (VSM), X-ray photoelectron spectroscopy (XPS), elemental analysis, FT-IR and Raman microprobe...