A unique parameterization for the transition potential in muonic x-rays

A single-parameter form approximating the transition potential in muonic atoms is presented. The single-parameter form yields comparable results with that obtained by the Barrett form in radial moment analysis. The single parameter,β, is isotopically independent and is uniquely defined by the particular transition of a given element.     

Spectrophotometric study of molecular complex formation between o-chloranil and a series of methylated pyridines

o-Chloranil has been shown to form 1:1 molecular complexes with pyridine and 2-, 3- and 4-picolines in CCl4 medium. Isosbestic points have been found but charge-transfer bands could not be detected. The formation constants of the complexes exhibit a very good linear free energy relationship from which the Hammett p parameter for the complexation reaction is found to be -3.67.     

Optical rotatory dispersion of rare earth crystal

The ORD spectrum of optically active single crystal of praseodymium oxydiacetate has been studied in the visible range at 77 K. The results have been compared with those obtained in the cases of transition metal complexes and other RE complexes with optically active ligands, and correlated with the site symmetry of the RE ion in the crystal. The optical activity has been related to the magnetic dipole strengths of the transitions.     

Crystal and molecular structure of di(2-methylbenzotriazole) sulfate, (C7N3H9)2SO4

The structure of di(2-Methylbenzotriazole) sulphate, (C₇N₃H₉)₂SO₄, has been solved by X-ray diffraction methods. The compound crystallises in triclinic space group P witha=6.986(1),b=18.914(1),c=6.990(1) Å, =95.083 (1), =115.56 (1) and =84.93(1)^o, respectively.M _r=362.36,F(000)=380,Z=2,D _m=1.45 mg m^–3, finalR=0.060,R _w=0.064. The structure was solved by direct methods (SHELXS86) and refined by least-squares methods. Dimers of planar 2-Methylbenzotriazole (MBT) molecules form stacks, one along thea-axis and the other parallel to thec-axis. The SO ₄ ^–2 ions are confined by the two sets of stacks and are responsible for holding them together. The structure is mainly stabilized by the stacking forces. The average interplanar distances in any stack are 3.281 Å, within a dimer, and 3.361 Å, between the dimers.     

Influences of cooperative hydrogen bonding economy on protein-nucleic acid complexation: Structure of unidecahydrated Inosine C5′-monophosphate and L-glutamine (2C10H13N4O8P · C5H10N2O3 · 11H2O) cocrystal at atomic resolution

The crystal structure of a unidecahydrated co-complex between two Inosine 5-monophosphate (IMP) and one L-glutamine has been determined at atomic resolution by X-ray crystallographic methods. The crystal belongs to the monoclinic space group P2₁ with cell dimensions a = 8.690(2), b = 21.900(3), c = 12.370(1) Å, and = 110.59(3)°. This structure reveals the recognition mechanism of glutamine to the nucleotide through direct and water-mediated hydrogen bonds. The phosphate oxygen (O23) seems to prefer the nonspecific interaction with the functional sites of glutamine (NA···O23 = 2.672, OH···O23 = 3.063, OE···O23 = 3.104 Å), whereas the bases prefer specific (N23···O = 2.874 Å) bindings. But here no specific interaction has been observed at N17 and N27, which were observed in serine—IMP complex. However, the solvent mediated N17···OW3···N27 hydrogen bonds for stabilization of the stacked purine bases have been observed as in other aminoacid-nucleotide cocrystals. The striking habit of glutamine to occupy the nearly same region of the nucleotide cocrystal as was found in the serine—IMP complex through substantial replacement of free and bound water molecules, shows certainly the cooperative hydrogen bonding economy of water molecules.