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Cucurbiturils are magnificent macrocycles that are used as precise molecules for the fabrication of supramolecular chemotherapeutic agents through host-guest molecular recognition. In the present work, the host-guest complex of cucurbit[6]uril (CB[6]) with 5-fluorouracil (Flu, an anticancer drug) is synthesized and its structural study was carried out using UV, XRD, and TG/DTA techniques. The UV-Vis spectrum of the inclusion complex exhibited maximum absorbance with a blue shift at 302 nm whereas the maximum absorbance for free CB[6] was observed at 318 nm. This notable shift in wavelength proves the formation of the inclusion complex of CB[6] with fluorouracil. The host-guest complex of fluorouracil with CB[6] shows sharp endothermic peaks at 403.30C with a heat flow of -0.5 mW/mg the peak covers partially an area of 528.2 J/g, The large variations observed in the DSC curves of the complex compared with free host CB[6] confirm the formation of a stable host-guest complex. The XRD pattern of the host-guest complex is different from the parent compound and this reaffirms the formation of host-guest complex. The cytotoxic effect of 5-fluorouracil and the host-guest complex of CB[6] with fluorouracil on KB cells was determined by MTT assay and the cytotoxicity of anticancer drug Flu towards cancer cells significantly increases by encapsulating 5-fluorouracil into the hydrophobic cavity of CB[6], The ROS generation study was carried out by measurement of intracellular ROS using fluorescent and chemiluminescent probe. The ROS generation of anticancer drugs against cancer cells is significantly increased by encapsulating 5-fluorouracil into the hydrophobic cavity of CB[6], The inclusion complex of cucurbituril with fluorouracil treatment in KB cells showed higher anticancer potential than fluorouracil treatment in KB cells when compared to the control. The IC50 value of 5-flurouracil was found to be higher compared to the inclusion complex of cucurbituril with fluorouracil. The interesting results obtained, might open new avenues for the use of CB[6] host-guest complexes in anticancer and drug delivery studies. [ABSTRACT FROM AUTHOR]

Thiazolo[3,2-a]pyrimidines namely ethyl 2-acetyl-5-(2-fluorophenyl)-3,7-dimethyl-5H-thiazolo[3,2-a]pyrimidine-6-carboxylate 3a, ethyl 2-acetyl-5-(3-fluorophenyl)-3,7-dimethyl-5H-thiazolo[3,2-a]pyrimidine-6-carboxylate 3b, and ethyl 2-acetyl-5-(4-fluorophenyl)-3,7-dimethyl-5H-thiazolo[3,2-a]pyrimidine-6-carboxylate 3c were obtained by one pot synthesis using substituted 3,4 dihydropyrimidine2-thione (1a–1c) and 3-chloro-2,4-pentanedione in ethanol and characterized by single-crystal X-ray diffraction. The variation in the position of fluorine atom on pyrimidine nucleus and insight into the self-assembly of compounds with varied types of non-covalent interactions has great influence on crystal packing. [ABSTRACT FROM AUTHOR]

The single phase HfxCe1−xO2 (x = 0.01, 0.05 and 0.1) nanoparticles were produced via microwave refluxing technique. The substitution of Hf-ions into CeO2 lattice has been demonstrated by X-ray diffraction and transmission electron microscopy analyses. X-ray photoelectron spectroscopy analysis indicated that Ce was present in + 3 and + 4 states whereas Hf in + 4 state. Raman, UV-Vis and photoluminescence spectroscopic analyses revealed the formation of surface defects including oxygen vacancies in the samples. The estimated defect concentration was 1.09 × 1021, 1.32 × 1021 and 1.49 × 1021 cm−3 for x = 0.01, 0.05 and 0.1 samples respectively. The room temperature ferromagnetic behavior for the samples originate from the surface oxygen vacancies. The prevalence of ferromagnetic clusters considerably raised the MS value for x = 0.05 sample. The augmentation in the MS values with increased Hf concentration could be attributed to the increase in the defect concentration. [ABSTRACT FROM AUTHOR]

NiMnZnFeO ( x = 0.0-0.6) samples were synthesized using a combustion technique involving a mixture of hexamine and metal nitrate. XRD measurements confirmed the single-phase formation. The lattice parameters were found to increase gradually with increasing Mn substitution. The peak broadening observed for these ferrites indicates their nanocrystalline nature. FTIR spectra display two absorption bands which are characteristics of M-O stretching in tetrahedral and octahedral sites in the spinel lattice. SEM observations show that the particles occur as loose agglomerates. Lower DC resistivity values in the range of 10 to 10 Ωcm observed at room temperature suggests the protonic conductivity due to moisture trapped inside the pores. The resistivity was found to decrease with increasing Mn substitution at higher temperatures. AC susceptibility studies reveal the presence of clusters of both superparamagnetic and single-domain particles. Curie temperatures were found to decrease with increasing Mn concentration. The low dielectric losses of about 10 in the higher frequency region were observed. [ABSTRACT FROM AUTHOR]

Alloys of Fe-Si-B with varying compositions of Mn were prepared using high energy planetary ball mill for maximum duration of 120 h. X-ray diffraction (XRD) analysis suggests that Si gets mostly dissolved into Fe after 80 h of milling for all compositions. The residual Si was found to form an intermetallic FeSi. The dissolution was further confirmed from the field emission scanning electron microscopy/energy dispersive X-ray analysis (FE-SEM/EDX). With increased milling time, the lattice parameter and lattice strain are found to increase. However, the crystallite size decreases from micrometer (75-95 μm) to nanometer (10-20 nm). Mössbauer spectra analysis suggests the presence of essentially ferromagnetic phases with small percentage of super paramagnetic phase in the system. The saturation magnetization ( M), remanance ( M) and coercivity ( H) values for Fe-0Mn sample after 120 h of milling were 96.4 Am/kg, 11.5 Am/kg and 12.42 k Am, respectively. However, for Fe-10Mn-5Cu sample the M, H and M values were found to be 101.9 Am/kg, 10.98 kA/m and 12.4 Am/kg, respectively. The higher value of magnetization could be attributed to the favourable coupling between Mn and Cu. [ABSTRACT FROM AUTHOR]

The ultrathin channel in nanotube is an exciting host to encapsulate sub-nanometer size guest spices. The dynamics of confined C 60 s inside the nanoscale host tube have been investigated by various stimuli like e-beam irradiation, Ar-ion laser and Cu K α X-ray. It has been disclosed that the accelerating voltage of TEM higher than the threshold energies of the ballistic knockoff in carbon atoms can be used to understand the rotation of host species in the confined geometry. The radial breathing Raman mode of host SWCNTs has been studied to insight into the enhanced mobility of guest C 60 s at higher temperatures in the confined tube geometry of nanopeapod. We have highlighted the role of temperature as a function of kinetic energy of the confined C 60 s in SWCNTs and which leads to the reduction of stress in host–guest complex. The temperature-dependent XRD has been used to study the mobilities of C 60 molecules adsorbed onto the SWCNTs to move along the tube walls until they detect an opening to infuse in the confined space [ABSTRACT FROM AUTHOR]