Hamid Reza Aghabozorg

Ab initio DFT study of bisphosphonate derivatives as a drug for inhibition of cancer: NMR and NQR parameters.

DFT computations were carried out to characterize the 17Oand 2H electric field gradient, EFG, in various bisphosphonate derivatives. The computations were performed at the B3LYP level with 6-311++G (d,P) standard basis set. Calculated EFG tensors were used to determine the 17O and 2H nuclear quadrupole coupling constant, χ and asymmetry parameter, η. For better understanding of the bonding and electronic structure of bisphosphonates, isotropic and anisotropic NMR chemical shieldings were calculated for the 13C, 17O and 31P nuclei using GIAO method for the optimized structure of intermediate bisphosphonates at B3LYP level of theory using 6-311++G (d, p) basis set. The results showed that various substituents have a strong effect on the nuclear quadrupole resonance (NQR) parameters (χ, η) of 17O in contrast with 2H NQR parameters. The NMR and NQR parameters were studied in order to find the correlation between electronic structure and the activity of the desired bisphosphonates. In addition, the effect of substitutions on the bisphosphonates polarity was investigated. Molecular polarity was determined via the DFT calculated dipole moment vectors and the results showed that substitution of bromine atom on the ring would increase the activity of bisphosphonates.

Synthesis and Characterization of Re-, Mo-, and W-Doped Vanadium Oxide Nanotubes

In this research study for the first time, Re-, (Re + W)-, and (Re + Mo)-doped vanadium oxide nanotubes (VONTs) were synthesized. Doping of these elements into vanadium oxide nanotubes up to 10 at% was performed by using a sol–gel method. The structure and morphology of the nanotubes were investigated by x-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The obtained samples were found to have a tubular morphology, be nanosized, and be multiwalled with open ends. The outer diameter of the nanotubes varied from 50 to 100 nm and the inner diameter of them varied from 20 to 40 nm with a length of larger than 1 μm. The results showed that interlayer distances of the nanotubes for Re-doped VONTs were larger than those of (Re + W)-doped VONTs and (Re + Mo)-doped VONTs. In addition, interlayer distances of the (Re + W)-doped VONTs were larger than those of (Re + Mo)-doped VONTs.

Synthesis of Mo, W, and Mo- and W-Doped Multiwall VONTs via Sol-Gel and Hydrothermal Methods

Mo, W, and Mo and W were doped into multiwall vanadium oxide nanotubes. The syntheses were performed using sol-gel method followed by hydrothermal method. The synthesized samples were characterized by XRD, SEM, EDX, and TEM techniques. The XRD patterns of the synthesized samples indicated that Mo and W could be doped into VONTs totally up to 50%. The SEM and TEM images showed that the prepared samples have tubular and multiwall morphology and open ends.

Synthesis and investigation of anchored copper (II) complexes within MCM-41 as selective catalysts for epoxidation of olefins

In the present study, preparation, characterization and catalytic activity of encapsulated copper (II) complexes within MCM-41 were investigated. The mesoporous molecular sieve MCM-41 was synthesized and grafted with 3-(trimethoxysilyl)-1-propanethiol to give a thiol modified material (MCM-41-S). The prepared material successively was reacted with acrylic acid and acrylonitrile to give AA-MCM-41 and AN-MCM-41, respectively. Using hexamethyldisilazane and copper (II) chloride, copper (II) complexes in the cavities of MCM-41 (Cu-AA-MCM-41 and Cu-AN-MCM-41) were prepared. The presence of copper (II) complex on the surfaces of host matrix and the structure of prepared catalyst is investigated by FT-IR, inductively coupled plasma-optical emission spectroscopy (ICP-OES), powder X-ray diffraction (XRD) and BET nitrogen adsorption–desorption methods. The catalytic activities of the catalysts were studied in epoxidation of olefins. The results showed that activities of the prepared catalysts (Cu-AA-MCM-41 and Cu-AN-MCM-41) and their selectivity to corresponding epoxides were more than those of MCM-41. In addition, the synthesized heterogeneous catalysts were truly reusable.

Synthesis and Characterization of Ce1-xZrxO2 Nanopaticles

A series of crystalline Ce1-xZrxO2 nanoparticles (where x = 0, 0.25, 0.5, 0.75 and 1.0) have been prepared by (i) hydrothermal (ii) polymer based metal-complex precursor solution reactions. Hydrothermal method was performed with diethanol amine as hydrolysis catalyst. The effect of reaction conditions on the size of particles and their morphology were investigated. In the polymer based method, by calcination of suitable polymer precursor solutions at a temperature range between 300 and 450 °C along with variation in the period of time, the metal oxide powders were subsequently obtained. The prepared powders have been characterized by powder X-ray diffraction (XRD), X-ray Fluorescence (XRF) .These studies reveled that zirconium is a good host for insertion into Cerium oxide in fluorite structure. The as-prepared samples were further characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The average diameter of the nanoparticles were calculated from line broadening of XRD peaks and confirmed by SEM and TEM studies.