Asian Journal of Chemical Sciences

The origins of the molecular-chiral homogeneity that is the very basis of life remain a tantalizing mystery. Molecular chirality itself is manifest in its interaction with radiation, particularly as optical activity, although an intriguing alternative technique based in X-ray crystallography is being increasingly employed. Thus, X-ray diffraction with anomalous dispersion is currently believed to lead to the absolute configuration of a stereogenic center, the ultimate goal of structural chemistry. However, despite its apparently unerring consistency, the fundamental basis of the anomalous dispersion technique is itself enigmatic. This is because it is unclear how the technique not only distinguishes two enantiomeric lattices but also assigns the absolute configuration: all, apparently, in the absence of an external chiral influence! Indeed, as argued previously, it is highly likely that the technique succeeds because the X-rays employed are circularly polarized, itself a possible consequence of parity violation. All the same, the question of how the absolute configuration is assigned remains, as the chiral sense of the putative circular polarization of the X-rays is unknown. It is argued herein that the anomalous dispersion method is essentially based in the chirality of X-rays that must have entered–although unbeknownst as such–into the calculations leading to the absolute configuration. In fact, the enigma surrounding the anomalous dispersion method derives from uncertainties concerning the theory of X-ray diffraction itself, thus leading to the apparently inescapable conclusion that both methods are essentially empirical — but without detracting from the brilliance of the scientific achievements that led to these methods.          

A new chalcone derivative (2E, 4E)-5-(4-(dimethylamino) phenyl)-1-(naphthalen-2-yl) penta-2,4-dien-1-one (DPNP) has been synthesized using Claisen-Schmidt condensation reaction using the slow evaporation method at ambient temperature. The 3D crystal structure was solved using the single-crystal X-ray diffraction method (XRD). XRD study reveals that the title compound crystallizes in a monoclinic crystal system with centrosymmetric space group P2₁/c with lattice parameters; a = 17.1467(10), b = 11.0395(7), c = 9.5821(5) Å β= 98.43(2)°. The packing diagram shows that the adjacent molecules are linked through a pair of C-H···O hydrogen bonds forming an inversion dimer. Hirshfeld surface mapped over the properties such as d_norm, Electrostatic potential, shape index, curvedness, and energy framework were also analyzed. The in-silico investigation of the title molecule discloses the efficacious for use as a drug in inhibiting breast Cancer.

The chemical compound 6-hydromethyl-4-methoxy-4- methoxytetrahydro-pyran-2, 3, 5-triol (C₇H₁₄O₆), was derived from the ethanol extract of Senna auriculata flower via GC-MS. FT-IR and NMR characterization of the compound support covalent bonding information and degree of degeneracy, respectively. 3D molecular structure was optimized to enhance the accuracy of computations. MEP, NBO, HOMO-LUMO, and Mulliken charge distribution studies provide details like reactive sites, electron density dislocation, and molecular interactions, charge transfer within the molecule and frontier orbital energies, electron density on the individual atom, and these were computed using hybrid B3-LYP quantum level with 6-311++G(d, p) basis set. Thermodynamic properties such as heat capacity, entropy, enthalpy, and their relation with temperature changes for the title molecule were also analyzed using THERMO.PL software. Non-linear optical properties namely polarizability, first-order hyperpolarizability, and electronic dipole moment have also been computed at B3-LYP level with 6-311++G (d, p) basis set. Docking simulation was initiated on the title molecule using Autodock 4.2 software and found to be an excellent inhibitor of ALR2, an enzyme.

Evaluation of physicochemical parameters and heavy metal levels in surface water of the Miniokoro stream, Port Harcourt, Nigeria were investigated to determine its potability and pollution status at various stations along the stream.  The physicochemical parameters analyzed in the water samples were: pH, Temperature, Salinity, Electrical conductivity, TDS, DO, BOD, Alkalinity, Chloride, NH₄⁺, NO₃^-, PO₄^3-, SO₄^2- while heavy metals such as Nickel, lead, Iron, Zinc and Chromium were analyzed using atomic absorption spectrophotometer. The results from the research showed an average concentration level of the physicochemical parameters such as pH (5.79-7.01), EC (136.43 - 960.67µS/cm), TDS (90.17 - 1517.67) and the spatial distribution of heavy metals: zinc (0.07 - 1.09mg/l), chromium (0.03 - 0.09mg/l), nickel (0.07 - 0.08mg/l) and iron (12.29 - 39.95mg/l). Water samples from various stations depicts the varying level of pollution along the stream when compared with national and international permissible limit. Thus, it suggests that the government should develop and implement an effective waste management plans due to environmental and other anthropogenic impacts on the stream.

Local chickens sold in the central markets of Ado-Ekiti, Akure and Owena were randomly sampled and slaughtered. Lead (Pb), cadmium (Cd) and zinc (Zn) in their blood and selected organs (intestine, heart, liver and gizzard) were isolated using wet digestion and their concentrations determined using atomic absorption spectrophotometer. Apart from the blood of chickens from Ado-Ekiti and Owena where Pb was not detected, its concentrations in the blood and organs of the chickens obtained from the three towns ranged from 2.00 to 7.33 mg/kg, exceeding the maximum tolerance levels (0.1 mg/kg) in internal organs of poultry birdsset by EU, ANZFA and FAO/WHO. With the exception of intestine of chickens from the three towns, Cd was only detected in the heart, blood and gizzard of chickens from Akure as well as liver and gizzard of chickens from Owena, covering a range of 0.11 to 0.67 mg/kg. The upper limit exceeded the maximum limits (0.5 mg/kg) according to FAO/WHO. Zn was detected in all selected parts of chickens from the three towns ranging 5.67 to 183.17 mg/kg. Its concentrations were within the permissible limit(10-50 mg/kg) by EU and FAO/WHO in certain selected parts of some chickens while it exceededthe permissible limit (150 mg/kg) by ANZFA especially in the liver of chicken from Ado-Ekiti. Some organs and blood of local chickens sold in the central markets at Ado-Ekiti, Akure and Owena may pose health risks.