The Experts below are selected from a list of 315 Experts worldwide ranked by ideXlab platform

Abdolkarim Chehregani Rad - One of the best experts on this subject based on the ideXlab platform.

Mehdi Shahraki - One of the best experts on this subject based on the ideXlab platform.

  • variable temperatures 1h nmr technique on the kinetics and thermodynamic parameters of equilibrium between the z and e isomers in a stable Phosphorus Ylide involving an imidazole
    RSC Advances, 2016
    Co-Authors: Elham Aghdaei, Sayyed Mostafa Habibikhorassani, Mehdi Shahraki
    Abstract:

    Analysis of 1H NMR spectra of a special Ylide involving an imidazole at variable temperatures has been employed to study the kinetics of the interchangeable process in the equilibrium between the two Z- and E-isomers of a stable Phosphorus Ylide. Activation data (k−1, k1, ktotal, Ea1, Ea−1, Eatotal, ΔH‡, ΔG‡, ΔS‡) and thermodynamic parameters (Ke, ΔH°, ΔG° and ΔS°) for the forward and reverse steps of the opposing reaction were obtained by means of the variable temperature 1H NMR technique and T-jump method. The 1H NMR results indicate that the interchangeable process of rotational isomers follows first-order kinetics with respect to both the forward and reverse reactions. The process was also entropy controlled.

  • dynamic 1h nmr studies of hindered internal rotations in the synthesized particular Phosphorus Ylide experimental and theoretical approaches
    Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2015
    Co-Authors: Sayyed Mostafa Habibikhorassani, Mehdi Shahraki, Malek Taher Maghsoodlou, Susan Erfani
    Abstract:

    Dynamic (1)H NMR measurements were performed within the synthesized particular Phosphorus Ylide involving 4-formylphenyl phenylcarbamate. Four rotational process and thereby parameters were targeted for rotation around the CC, C-C, HCNC and OCNC bonds. The Gibbs free activation energy in CDCl3, ΔG(≠)exp, was found to be 64 ± 2, 50 ± 2, 41 ± 2 and 63 ± 2, respectively. These findings were compared with related ab initio and DFT results on simulated situation. Theoretical methods tested, were comparable to the present D (1)H NMR data.

  • theoretical study around the c c bond in a stable Phosphorus Ylide derived from hexamethylphosphorous triamide
    2014
    Co-Authors: Fatemeh Ghodsi, Mehdi Shahraki, Sayyed Mostafa Habibikhorassani
    Abstract:

    A theoretical study has been performed within the Phosphorus Ylide derived from hexamethylphosphorous triamide around the carbon-carbon double bond (OCH3-C C-P(NMe2)3) using ab initio and DFT methods at the HF/6-31G** and B3LYP/6-31G** levels of theory in gas phase. Also, effects of temperature and solvent media were investigated. The results showed that the B3LYP/6-31G** level at solvent media and experimental temperatures provides better data in relation to experimental dynamic 1 H NMR data.

  • Intramolecular hydrogen bonding in chemoselective synthesized 2-substituted pyrrole stable Phosphorus Ylide: GIAO, AIM, and NBO approaches
    Structural Chemistry, 2013
    Co-Authors: Mehdi Shahraki, Malek Taher Maghsoodlou, Sayyed Mostafa Habibi-khorassani, Ali Ebrahimi, Younes Ghalandarzehi
    Abstract:

    The chemoselectivity of geometrically Ylide compounds is often hard to assign from experimental techniques, particular system with intramolecular hydrogen bonding (IHB) are even more challenging. Herein, theoretical calculations were performed to investigate whether theoretical results would provide consistent evidence for the existence of IHB to confirm experimental data and to evaluate strength of the N–H···O IHB from geometrical synthesized 2-substituted pyrrole stable Phosphorus Ylide (dimethyl 2-(1 H -pyrrol-2-yl)-3-(triphenylphosphoranYlidene) butanedioate in a single chemoselective compound. Topological parameters at the bond critical points (BCP) of intramolecular hydrogen bonds from Bader’s atoms in molecules (AIM) theory and Winhold’s natural bond orbital (NBO) calculations were analyzed at the B3LYP/6-311++g** level in details. A series of gage-including atomic orbital chemical shift (GIAO c.s.) calculations at the HF and DFT levels of theory were carried out to assign the ^1H NMR chemical shifts. The best prediction of the experimental ^1H NMR values was obtained at the mPW1PW91 levels using the 6-31G** basis set. Theoretical results, in agreement with the experimental data, were confirmed the N–H···O IHB was caused the deshielding of the proton to lower field. The barriers in double bond and single bond rotation were theoretically estimated in detailed and the AIM and NPA approaches were confirmed the loss of charge of the hydrogen atom involving in intramolecular N–H···O hydrogen bonding. The geometrical and topological parameters from AIM and NBO analyses were indicated the medium N–H···O IHB.

  • intramolecular hydrogen bonding in chemoselective synthesized 2 substituted pyrrole stable Phosphorus Ylide giao aim and nbo approaches
    Structural Chemistry, 2013
    Co-Authors: Mehdi Shahraki, Sayyed Mostafa Habibikhorassani, Malek Taher Maghsoodlou, Ali Ebrahimi, Younes Ghalandarzehi
    Abstract:

    The chemoselectivity of geometrically Ylide compounds is often hard to assign from experimental techniques, particular system with intramolecular hydrogen bonding (IHB) are even more challenging. Herein, theoretical calculations were performed to investigate whether theoretical results would provide consistent evidence for the existence of IHB to confirm experimental data and to evaluate strength of the N–H···O IHB from geometrical synthesized 2-substituted pyrrole stable Phosphorus Ylide (dimethyl 2-(1H-pyrrol-2-yl)-3-(triphenylphosphoranYlidene) butanedioate in a single chemoselective compound. Topological parameters at the bond critical points (BCP) of intramolecular hydrogen bonds from Bader’s atoms in molecules (AIM) theory and Winhold’s natural bond orbital (NBO) calculations were analyzed at the B3LYP/6-311++g** level in details. A series of gage-including atomic orbital chemical shift (GIAO c.s.) calculations at the HF and DFT levels of theory were carried out to assign the 1H NMR chemical shifts. The best prediction of the experimental 1H NMR values was obtained at the mPW1PW91 levels using the 6-31G** basis set. Theoretical results, in agreement with the experimental data, were confirmed the N–H···O IHB was caused the deshielding of the proton to lower field. The barriers in Open image in new window double bond and Open image in new window single bond rotation were theoretically estimated in detailed and the AIM and NPA approaches were confirmed the loss of charge of the hydrogen atom involving in intramolecular N–H···O hydrogen bonding. The geometrical and topological parameters from AIM and NBO analyses were indicated the medium N–H···O IHB.

Seyyed Javad Sabounchei - One of the best experts on this subject based on the ideXlab platform.

  • new stable Phosphorus Ylide p tolyl 3p chcoc6h4 p cn and its metal complexes crystal and molecular structure theoretical study and antibacterial investigation
    Journal of Coordination Chemistry, 2020
    Co-Authors: Leila Vatannavaz, Seyyed Javad Sabounchei, Asieh Sedghi, Kristof Van Hecke, Mehdi Bayat, Abdolkarim Chehregani Rad
    Abstract:

    AbstractA new stable Phosphorus Ylide (p-tolyl)3P = CHCOC6H4(p-CN) (Y) was synthesized and a series of novel complexes based on metalated Phosphorus Ylides were prepared through the reaction of (p-...

  • New stable Phosphorus Ylide (p-tolyl)3P = CHCOC6H4 (p-CN) and its metal complexes: Crystal and molecular structure, theoretical study and antibacterial investigation
    Journal of Coordination Chemistry, 2020
    Co-Authors: Leila Vatannavaz, Seyyed Javad Sabounchei, Asieh Sedghi, Kristof Van Hecke, Mehdi Bayat, Abdolkarim Chehregani Rad
    Abstract:

    AbstractA new stable Phosphorus Ylide (p-tolyl)3P = CHCOC6H4(p-CN) (Y) was synthesized and a series of novel complexes based on metalated Phosphorus Ylides were prepared through the reaction of (p-...

  • ^31P NMR study of the stoichiometry, stability, and thermodynamic data for the complexation of several HgX_2: acetylemethylene tripara tolyl phosphorane complexes in various tetrahydrofuran–dimethyl sulfoxide mixtures
    Journal of the Iranian Chemical Society, 2019
    Co-Authors: Mohammad Hasan Zebarjadian, Leila Vatannavaz, Seyyed Javad Sabounchei
    Abstract:

    Hg(II) halides are shown to react with the unsymmetrical Phosphorus Ylide, CH_3COCHP(p-tolyl)_3 (Y) to be shaped binuclear products with the composition {HgX_2[CH_3COCHP(p-tolyl)_3(Y)]}_2, where X  = I, Br, and Cl. ^31P NMR measurements were occupied to monitor the stability and stoichiometry of Phosphorus Ylide complexes with HgX_2 in binary tetrahydrofuran–dimethyl sulfoxide mixtures of changing composition. In all instance studied, the change of ^31P chemical shift with the [HgX_2]/[Y] mole ratio showed the formation of 1:1 complexes. The stable constants of the arising from complexes were appraised from computer fitting of the mole ratio information to an equation that relates the monitored chemical shifts to the stable constant. In all solvent mixtures studied, the stabilities of the consequence 1:1 complexes varied in the order HgI_2 

  • binuclear and polymeric hg ii complexes of an ambidentate Phosphorus Ylide synthesis crystal structure antibacterial activity and theoretical studies
    ISSN: 0268-2605, 2019
    Co-Authors: Seyyed Javad Sabounchei, Faeze Kazemi Andalib, Marjan Hosseinzadeh, Asieh Sedghi, Ali Hashemi, Roya Karamian, Kristof Van Hecke
    Abstract:

    The new alpha-keto-stabilized Phosphorus Ylide Ph3PCHC(O)PhCN (Y) was synthesized by addition of triphenylphosphine to 2-bromo-4 '-cyanoacetophenone, followed by treatment with NaOH 10%. Reaction of ligand (Y) with methanolic solution of mercury(II) halides under mild conditions yielded the binuclear complexes [Y center dot HgX2](2) [X=Cl (1), Br (2), I (3)]. The new organic/inorganic composite polymer [Hg(NO3)(2)(Y)](n) (4) was synthesized by the reaction of mercury(II) nitrate with the Phosphorus Ylide Y. Compounds synthesized were characterized by Fourier-transform infrared, H-1, P-31, and C-13 nuclear magnetic resonance spectroscopic methods, which confirmed the coordination of Ylide to the metal center through the ylidic carbon atom. Single-crystal X-ray structures of Phosphorus Ylide Y and polymeric complex 4 were also determined and the crystallographic data of complex 4 showed that the title complex has an infinite one-dimensional structure. Furthermore, the electronic and molecular structures of complexes 1-3 were investigated at the BP86/def2-SVP level of theory, indicating an increasing trend for C -> M bond lengths: Hg2I2 > Hg2Br2 > Hg2Cl2 in [Y -> HgX2](2) (X = Cl, Br, I) complexes. In addition, the antibacterial activity of ligand Y and all complexes using the agar disc diffusion method was examined against both selected gram-positive and gram-negative bacteria. Results indicated that the ligand Y and complexes 1 and 4 show good antibacterial effect against gram-positive bacteria tested; besides, the inhibition zones of complexes were significantly larger than those of chloramphenicol as standard.

  • new pallada and platinacycle complexes of Phosphorus Ylide synthesis structural characterization antioxidant capacity and catalytic behavior towards mizoroki heck reactions
    Polyhedron, 2017
    Co-Authors: Seyyed Javad Sabounchei, Ali Hashemi, Roya Karamian, Mostafa Asadbegy, Abed Yousefi, Parviz Gohari Derakhshandeh, Kristof Van Hecke
    Abstract:

    Abstract The reactions of α-keto stabilized Phosphorus Ylide Ph2P(CH2)2PPh2C(H)C(O)C6H4-m-Br (Y) with [MCl2(cod)] (M = Pd or Pt; cod = 1,5-cyclooctadiene) in equimolar ratio using dichloromethane as a solvent are reported. These reactions led to the formation of new P, C-chelated pallada- and platinacycle complexes [MCl2(Ph2P(CH2)2PPh2C(H)C(O)C6H4-m-Br)] (M = Pd (C1) and Pt (C2)). Characterization of the obtained compounds was performed by elemental analysis and IR, 1H, 13C, and 31P NMR spectroscopic methods. Also, the unequivocal structures of these complexes were characterized crystallographically. Both structures consist of six-membered rings formed by coordination of the Phosphorus Ylide (Y) through the phosphine group and the ylidic carbon atom to the metal center. Furthermore, palladacycle C1 was employed as an efficient catalyst in the Mizoroki-Heck coupling reaction of several aryl chlorides and olefins. The coupled products of these reactions were obtained under aerobic conditions in high yields using aqueous DMF as a solvent. Additionally, the antioxidant capacity of the reported compounds with butylated hydroxytoluene (BHT) as standard was evaluated by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging method. Apparently, all synthesized compounds possess strong antioxidant capacity (IC50; 0.584 ± 0.009–0.751 ± 0.003 mg/ml).

Leila Vatannavaz - One of the best experts on this subject based on the ideXlab platform.

Kristof Van Hecke - One of the best experts on this subject based on the ideXlab platform.

  • new stable Phosphorus Ylide p tolyl 3p chcoc6h4 p cn and its metal complexes crystal and molecular structure theoretical study and antibacterial investigation
    Journal of Coordination Chemistry, 2020
    Co-Authors: Leila Vatannavaz, Seyyed Javad Sabounchei, Asieh Sedghi, Kristof Van Hecke, Mehdi Bayat, Abdolkarim Chehregani Rad
    Abstract:

    AbstractA new stable Phosphorus Ylide (p-tolyl)3P = CHCOC6H4(p-CN) (Y) was synthesized and a series of novel complexes based on metalated Phosphorus Ylides were prepared through the reaction of (p-...

  • New stable Phosphorus Ylide (p-tolyl)3P = CHCOC6H4 (p-CN) and its metal complexes: Crystal and molecular structure, theoretical study and antibacterial investigation
    Journal of Coordination Chemistry, 2020
    Co-Authors: Leila Vatannavaz, Seyyed Javad Sabounchei, Asieh Sedghi, Kristof Van Hecke, Mehdi Bayat, Abdolkarim Chehregani Rad
    Abstract:

    AbstractA new stable Phosphorus Ylide (p-tolyl)3P = CHCOC6H4(p-CN) (Y) was synthesized and a series of novel complexes based on metalated Phosphorus Ylides were prepared through the reaction of (p-...

  • binuclear and polymeric hg ii complexes of an ambidentate Phosphorus Ylide synthesis crystal structure antibacterial activity and theoretical studies
    ISSN: 0268-2605, 2019
    Co-Authors: Seyyed Javad Sabounchei, Faeze Kazemi Andalib, Marjan Hosseinzadeh, Asieh Sedghi, Ali Hashemi, Roya Karamian, Kristof Van Hecke
    Abstract:

    The new alpha-keto-stabilized Phosphorus Ylide Ph3PCHC(O)PhCN (Y) was synthesized by addition of triphenylphosphine to 2-bromo-4 '-cyanoacetophenone, followed by treatment with NaOH 10%. Reaction of ligand (Y) with methanolic solution of mercury(II) halides under mild conditions yielded the binuclear complexes [Y center dot HgX2](2) [X=Cl (1), Br (2), I (3)]. The new organic/inorganic composite polymer [Hg(NO3)(2)(Y)](n) (4) was synthesized by the reaction of mercury(II) nitrate with the Phosphorus Ylide Y. Compounds synthesized were characterized by Fourier-transform infrared, H-1, P-31, and C-13 nuclear magnetic resonance spectroscopic methods, which confirmed the coordination of Ylide to the metal center through the ylidic carbon atom. Single-crystal X-ray structures of Phosphorus Ylide Y and polymeric complex 4 were also determined and the crystallographic data of complex 4 showed that the title complex has an infinite one-dimensional structure. Furthermore, the electronic and molecular structures of complexes 1-3 were investigated at the BP86/def2-SVP level of theory, indicating an increasing trend for C -> M bond lengths: Hg2I2 > Hg2Br2 > Hg2Cl2 in [Y -> HgX2](2) (X = Cl, Br, I) complexes. In addition, the antibacterial activity of ligand Y and all complexes using the agar disc diffusion method was examined against both selected gram-positive and gram-negative bacteria. Results indicated that the ligand Y and complexes 1 and 4 show good antibacterial effect against gram-positive bacteria tested; besides, the inhibition zones of complexes were significantly larger than those of chloramphenicol as standard.

  • new pallada and platinacycle complexes of Phosphorus Ylide synthesis structural characterization antioxidant capacity and catalytic behavior towards mizoroki heck reactions
    Polyhedron, 2017
    Co-Authors: Seyyed Javad Sabounchei, Ali Hashemi, Roya Karamian, Mostafa Asadbegy, Abed Yousefi, Parviz Gohari Derakhshandeh, Kristof Van Hecke
    Abstract:

    Abstract The reactions of α-keto stabilized Phosphorus Ylide Ph2P(CH2)2PPh2C(H)C(O)C6H4-m-Br (Y) with [MCl2(cod)] (M = Pd or Pt; cod = 1,5-cyclooctadiene) in equimolar ratio using dichloromethane as a solvent are reported. These reactions led to the formation of new P, C-chelated pallada- and platinacycle complexes [MCl2(Ph2P(CH2)2PPh2C(H)C(O)C6H4-m-Br)] (M = Pd (C1) and Pt (C2)). Characterization of the obtained compounds was performed by elemental analysis and IR, 1H, 13C, and 31P NMR spectroscopic methods. Also, the unequivocal structures of these complexes were characterized crystallographically. Both structures consist of six-membered rings formed by coordination of the Phosphorus Ylide (Y) through the phosphine group and the ylidic carbon atom to the metal center. Furthermore, palladacycle C1 was employed as an efficient catalyst in the Mizoroki-Heck coupling reaction of several aryl chlorides and olefins. The coupled products of these reactions were obtained under aerobic conditions in high yields using aqueous DMF as a solvent. Additionally, the antioxidant capacity of the reported compounds with butylated hydroxytoluene (BHT) as standard was evaluated by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging method. Apparently, all synthesized compounds possess strong antioxidant capacity (IC50; 0.584 ± 0.009–0.751 ± 0.003 mg/ml).