3153-26-2Relevant academic research and scientific papers
Selective oxidation of sulfides to sulfoxides in water using 30% hydrogen peroxide catalyzed with a recoverable VO(acac)2 exchanged sulfonic acid resin catalyst
Prasanth, K. Leon,Maheswaran
, p. 45 - 49 (2007)
Various types of sulfides are selectively oxidized to sulfoxides in good to excellent yields in aqueous media using 30% aqueous hydrogen peroxide as an oxidant in the presence of catalytic amounts of a VO(acac)2-exchanged strongly acidic polymeric resin catalyst in water at room temperature. The catalyst can be recovered and reused at least five times without loss of activity and selectivity.
Thermal Stability of Substituted Pyridine Adducts of Bis(acetylacetonato)-oxovanadium(IV) in Solid State
Shibutani, Yasuhiko,Shinra, Koichiro
, p. 1477 - 1481 (1989)
The kinetic of the elimination reaction of axial ligand B in 2B> complexes (Hacac = acetylacetone;B = pyridine, its derivatives, and ammonia) was studied in solid state by the Coats-Redfern method.The frequency factor and activation en
Volatility and thermal stability of vanadyl β-diketonate complexes
Malkerova,Makarevich,Alikhanyan,Kuz’mina
, (2017)
Thermal behavior and thermodynamic characteristics of vanadyl β-diketonates—acetylacetonate VO(acac)2, dipivaloylmethanate VO(thd)2, and tris-hexafluoroacetylacetonate VO(hfa)2 (Hacac, 2,4-pentanedione; Hthd, 2,2,6,6-tetra
Composition and geometry of oxovanadium(IV) and (V)-aminoethanol-Schiff base complexes and stability of their peroxo complexes in solution
Ando, Ryuji,Nagai, Mayumi,Yagyu, Takeyoshi,Maeda, Masunobu
, p. 107 - 113 (2003)
Vanadium(IV) and (V) complexes (VO(sal-ae)) with Schiff bases prepared from 2-aminoethanol and salicylaldehyde and its derivatives have been synthesized and characterized in solid and in solution by EPR, IR, and UV-Vis spectroscopy. The complexes of both V(IV) and V(V) contain bridges (V-O-V) by alkoxy oxygens(oxo) in the solid state. The complexes of V(IV) in dichloromethane are binuclear,in which two alkoxy oxygens serve as bridges between the two metal atoms. They are mononuclear with one solvent ligated in the equatorial plane in each complex in dimethyl sulfoxide and methanol. The extent of the formation and the stability of organic hydroperoxide complexes of V(V) prepared from the V(IV)-Schiff base complexes increase with decreasing donor number of the solvent. The difference in electron-donating and withdrawing ability of the substituent groups affects the A∥ values for the V(IV)-Schiff base complexes in DMSO.
Giant spin-phonon bottleneck effects in evaporable vanadyl-based molecules with long spin coherence
Tesi,Lunghi,Atzori,Lucaccini,Sorace,Totti,Sessoli
, p. 16635 - 16643 (2016)
Vanadium(iv) complexes have recently shown record quantum spin coherence times that in several circumstances are limited by spin-lattice relaxation. The role of the environment and vibronic properties in the low temperature dynamics is here investigated by a comparative study of the magnetization dynamics as a function of crystallite size and the steric hindrance of the β-diketonate ligands in VO(acac)2 (1), VO(dpm)2 (2) and VO(dbm)2 (3) evaporable complexes (acac- = acetylacetonate, dpm- = dipivaloylmethanate, and dbm- = dibenzoylmethanate). A pronounced crystallite size dependence of the relaxation time is observed at unusually high temperatures (up to 40 K), which is associated with a giant spin-phonon bottleneck effect. We model this behaviour by an ad hoc force field approach derived from density functional theory calculations, which evidences a correlation of the intensity of the phenomenon with ligand dimensions and the unit cell size.
Immobilized some of vanadium compounds on modified graphene oxide as nanofiber network for epoxidation of allyl alcohols
Farzaneh, Faezeh,Ahmadi, Zahra,Azarkamanzad, Zahra,Ghahremani, Maryam
, (2021)
VO(acac)2 and the in situ generated VO(Salen) complex were immobilized on the covalently modified graphene oxide (GO) with ethylenediamine (en) and designated as VO(acac)2@en-GO and VO@Salen@en-GO, respectively. Characterization of the prepared compounds was carried out with FT-IR, XRD, ICP, CHN, Raman, SEM, TEM, and BET techniques. The SEM results confirmed the formation a nanofiber network and nanointerconnected needles. The prepared immobilized complexes were then used as heterogeneous catalysts for epoxidation of some allyl alcohols such as geraniol, trans-2-hexene-1-ol, and 1-octen-3-ol. Based on the results obtained by GC and GC–mass analyses, epoxidation of geraniol with 97% conversion and 100% selectivity seemed promising. Readily recycling of the catalyst and reusing for four successive catalytic runs without significant loss of activity revealed that this catalysis system deserves nomination for practical application.
Performance of a non-aqueous vanadium acetylacetonate prototype redox flow battery: Examination of separators and capacity decay
Escalante-Garca, Ismailia L.,Wainright, Jesse S.,Savinell, Robert F.,Thompson, Levi T.
, p. A363 - A372 (2015)
Non-aqueous electrolytes are stable over wide electrochemical potential windows, generally a critical component that to a great extent determines the performance of RFB systems for practical applications. In this work, the performance of a RFB was evaluated with Nafion 1035 membranes and Daramic 175 SLImicroporous separators. The non-aqueous electrolyte was based on vanadium (III) acetylacetonate. This chemistry possesses two couples over ～2.2 V. Charge-discharge cycles were performed in a RFB at a current density of 10 mA cm-2. Coulombic and energy efficiencies of 91% and 80% were achieved using the Nafion membrane. A similar RFB using the Daramic microporous separator achieved columbic and energy efficiencies of 73% and 68%, respectively. The source of capacity decay during multiple charge-discharge cycles was also investigated. The loss in the capacity was related to the poor chemical stability of the vanadium acetylacetonate in the positive electrolyte during battery cycling.
New oxovanadium(IV) complexes with mixed ligands - Synthesis, thermal stability, and crystal structure of (VO)2(acac)2(μ-OEt) 2 and (VO)2(thd)2(μ-OEt)2
Ahmed,Fjellvag,Kjekshus,Klewe
, p. 2311 - 2318 (2004)
Synthesis, crystal structure, thermal stability, and magnetic properties of the new oxovanadium(IV) complexes [(VO)2L2(μ-OEt) 2] with mixed β-diketonato [L = acac = C5H 7O2 or L = thd = C11H19O 2-] and ethanolato (OEt) ligands are reported. The structure determinations of (VO)2(acac)2(μ-OEt) 2 [P21/c, with a = 14.775(2), b = 8.788(1), c = 15.742(2) A, β = 112.43(1)°] and (VO)2(thd)2(μ- OEt)2 [P1, with a = 8.871(3), b = 9.988(4), r = 10.299(4) A, α = 73.51(1), β = 68.70(1), γ = 65.85(1)°] are based on single-crystal X-ray diffraction data collected at 105 K. Structure data for VO(acac)2 and VO(thd)2 are redetermined at 105 and 295 K. (VO)2(acac)2(μ-OEt)2 and (VO) 2(thd)2(μ-OEt)2 comprise binuclear five-coordinated molecular units. The configuration of five oxygen atoms around a central vanadium atom is approximately square pyramidal in all the four studied complexes. (VO)2(thd)2(μ-OEt)2 exhibits conspicuous changes in unit-cell dimensions (expansion in a and c, shrinkage in b, and appreciable variation in α, β, and γ) on going from 105 to 295 K, which appear to reflect adjustments in the configuration of its (anti-arranged) ligands. The interatomic distances in the crystal structures are analyzed in terms of the bond-valence concept. The four-valent state of vanadium is verified by magnetic susceptibility measurements. All complexes are subject to sublimation.
Oxovanadium(IV), copper(II) or cobalt(II) acetylacetone complexes immobilized on amino-functionalized CMK-3 for the aerobic epoxidation of styrene
Wang, Xiufang,Wu, Shujie,Li, Zhifang,Yang, Xiaoyuan,Hu, Jing,Huo, Qisheng,Guan, Jingqi,Kan, Qiubin
, p. 698 - 706 (2015/09/28)
Oxovanadium(IV), copper(II) and cobalt(II) acetylacetone complexes have been grafted onto amino-modified CMK-3-O (VO-NH2-CMK-3, Cu-NH2-CMK-3 and Co-NH2-CMK-3,respectively) and the materials thus prepared were used as heterogeneous catalysts for the aerobic oxidation of styrene. X-ray diffraction, nitrogen adsorption-desorption and transmission electron microscopy measurements confirmed the structural integrity of the mesoporous hosts, and spectroscopic characterization techniques (Fourier transform infrared, X-ray photoelectron, Raman) and thermogravimetry confirmed the ligands and the successful anchoring of the acetylacetone complexes to the modified mesoporous support. VO-NH2-CMK-3 displayed a relatively good catalytic performance with 94.6% of styrene conversion using air as oxidant, while Cu-NH2-CMK-3 gave 99.6% of styrene conversion using tert-butyl hydroperoxide as oxidant.
Heterogeneous catalytic oxidation of styrene by an oxo bridged divanadium(V) complex of an acetohydrazide-Schiff base
Sadhukhan, Dipali,Maiti, Monami,Zangrando, Ennio,Pathan, Soyeb,Mitra, Samiran,Patel, Anjali
, p. 1 - 9 (2014/01/06)
We have synthesized a μ-oxido divanadium compound [(VOL) 2(μ-O)] with an aliphatic hydrazone ligand LH2 = (E)-N'-(1-(2-hydroxyphenyl)ethylidene)acetohydrazide. The complex was characterized by elemental analysis, IR and UV-Vis spectroscopy and the molecular structure was established by single crystal X-ray diffraction technique. The complex has been infused over alumina to prepare a heterogeneous catalyst which was characterized by IR spectroscopy, thermogravimetric and powder XRD analyses. The catalyst has been studied for the oxidation of styrene in presence of H2O2 and appears to be easily recyclable. A conversion of 99.7% and selectivity of 88.1% for benzaldehyde formation and a turnover number of 1354 was detected under the most favorable reaction conditions.
