Ali Haider

4-Methyl­benzyl 4-amino­benzoate

The dihedral angle between the two benzene rings in the title compound, C15H15NO2, is 65.28u2005(12)°. The crystal structure is stabilized by N—H⋯N and N—H⋯O hydrogen bonds, leading to the formation of supramolecular chains along the a-axis direction.

Tuning the band gap of TiO 2 by tungsten doping for efficient UV and visible photodegradation of Congo red dye

Tungsten-doped TiO2 (W@TiO2) nanoparticles, with different percentages of atomic tungsten dopant levels (range of 0 to 6u202fmol%) have been synthesized by the sol-gel method and characterized by UV-Visible spectroscopy, XRD, SEM, EDX, ICP-OES and XPS analysis. By means of UV-Vis spectroscopy, it has been observed that with 6u202fmol% tungsten doping the wavelength range of excitation of TiO2 has extended to the visible portion of spectrum. Therefore, we evaluated the photocatalytic activity of W@TiO2 catalysts for the degradation of Congo red dye under varying experimental parameters such as dopant concentration, catalyst dosage, dye concentrations and pH. Moreover, 6u202fmol%u202fW@TiO2 catalyst was deposited on a glass substrate to form thin film using spin coating technique in order to make the photocatalyst effortlessly reusable with approximately same efficiency. The results compared with standard titania, Degussa P25 both in UV- and visible light, suggest that 6u202fmol%u202fW@TiO2 can be a cost-effective choice for visible light induced photocatalytic degradation of Congo red dye.

Designing of new cationic surfactant based micellar systems as drug carriers: an investigation into the drug cell membrane interactions

Abstract This study highlights the utility of new pyridinium based cationic surfactants, N-(n-heptyl)-3-methylpyridinium bromide (Py7) and N-(n-nonyl)-3-methylpyridinium bromide (Py9), formed via a single step substitution reaction, for their application towards drugs delivery. Fourier-transform infrared (FT-IR) and nuclear magnetic resonance (NMR) spectroscopic methods have been employed for the characterization of these amphiphiles. Aggregation behavior of the surfactants in solution i.e. the critical micelle concentration (CMC), has been investigated by conductometric and spectrophotometric analyses. The results reveal that the amphiphiles can act as excellent surface active agents due to their low critical micelle concentration (CMC). Furthermore, the interaction of these surfactants with two anionic drugs i.e., Ketoprofen (KP, 2-(3-Benzoylphenyl)propanoic acid) and Diclofenac sodium (DF, Sodium 2-(2,6-dichloranilino) phenylacetate), has been explored below and above the CMC value using UV-visible spectroscopy. The enhanced absorption intensities of both the drugs in the presence of synthesized surfactants indicated stronger interactions between surfactants and drugs molecules. GRAPHICAL ABSTRACT

Synthesis, spectroscopic characterization, and biological screening of levofloxacin based organotin(IV) derivatives

Four new organotin (IV) complexes with general formula R3SnL/R2SnL2, where R = CH3, n-C4H9, C6H5 and L = Levofloxacin, were synthesized and characterized by elemental analyses, FT-IR and NMR (1H and 13C) spectroscopy. Spectroscopic data suggested a six-coordinated geometry for diorganotin(IV) derivatives and a five-coordinated geometry for triorganotin(IV) derivatives. The value of Me–Sn–Me bond angle for di- and trimethyltin complexes using the Lockhart equation, were 150° and 116°, respectively, that corresponded to six and five-coordinate geometry, accordingly. The ligand and its complexes were screened for their antibacterial, antifungal, cytotoxic, and free radical scavenging (DPPH) antioxidant activities. The biological data indicated those as potentially bioactive in each field of the study. Accumulated data of DNA interaction with the synthesized complexes based on UV-Vis, cyclic voltammetry and viscometry suggested an intercalative mode of the interaction.

Therapeutic properties of organotin complexes with reference to their structural and environmental features

Abstract Organotin complexes are being extensively studied and screened for their therapeutic potential. Although many recent advances and achievements in this field have been made, the exact mode of action of these complexes is yet to be unveiled. In the present review, an attempt has been made to correlate the therapeutic properties of organotin complexes with their structural features and the environment in which these interact with biological systems. The mechanism, various modes of interaction with biological systems, and physiological target sites of organotin complexes have been highlighted as well.

Synthesis, structural elucidation and biological activities of organotin(IV) derivatives of 4-(2-thienyl)butyric acid

A series of tri- and diorganotin(IV) derivatives of 4-(2-thienyl)butyric acid have been synthesized by the reaction of ligand acid with tri- and diorganotin salts in 1:1 and 2:1 molar ratios, respectively. The synthesized compounds have been confirmed by CHNS elemental analyses, FTIR, multinuclear NMR (1H and 13C) spectroscopy and X-ray diffraction studies. NMR data reveal a 5-coordinate geometry for the triorganotin(IV) derivatives, while 6-coordinate for the diorganotin(IV) derivatives, respectively. The X-ray crystallographic analysis of the compound 2 showed polymeric 5-coordinate trigonal bipyramidal geometry. Antimicrobial studies were also evaluated against different strains of bacteria (Escherichia coli, Klebsiella pneumoniae, Bacillus subtilis and Staphylococcus aureus) and fungi (Mucor species, Aspergillus solani, Helminthosporium oryzae, Aspergillus flavus, Aspergillus niger) to establish the biological significance of these compounds. The synthesized compounds probably work by interfering with the ability of bacteria to form cell walls by keeping unwanted substances from entering their cells and stop the contents of their cells from leaking out due which the bacteria get die. The antifungal activity of some of the tested compound is comparable to that of the standard drug, terbinafine. From their antimicrobial results, it was concluded that they might be used as potential candidate for the generation of new antimicrobial drugs.

2-{5-[2-(4-Nitro-phen-oxy)phen-yl]-1-phenyl-1H-pyrazol-3-yl}phenol.

In the title compound, C27H19N3O4, the phenol and pyrazole rings are almost coplanar [dihedral angle = 0.95u2005(12)°] due to an intramolecular O—H⋯N hydrogen bond, whereas the phenyl ring is tilted by 40.81u2005(7)° with respect to the plane of the pyrazole ring. The aromatic ring with a nitrophenoxy substituent makes a dihedral angle of 54.10u2005(7)° with the pyrazole ring.