Synthesis, crystal structure and luminescence properties of a cadmium(II) complex based on 2-hydroxy-6-methylisonicotinic acid

A new cadmium(II) complex [Cd(Hminic)(IP)]n (1, Hminic = 2-hydroxy-6-methylisonicotinic acid, IP = imidazo[4,5-f]-1,10-phenanthroline), has been synthesized by the reaction of a Hminic and auxiliary N-containing ligands with Cd(II) ion under hydrothermal conditions. The complex was studied by elemental analysis, IR spectroscopy and X-ray crystallography. It is formulated as C20H13CdN5O3, crystallizes in monoclinic system, space group C2/c with α = 9.6764(8), b = 26.767(2), c = 14.1332(11) Å and β = 97.4510(10)°. V = 3629.7(5) Å3, Z = 8, Mr = 483.75, Dc = 1.770 g/cm3, F(000) = 1484 and μ = 1.237 mm-1. The final refinement gave R = 0.0309 and wR = 0.0703 for 4151 reflections with I > 2σ(I). In the structure of 1, two Cd(II) atoms are joined by a pair of μ2-hydroxyl oxygen atoms giving rise to a dinuclear Cd(II) unit which is bridged by Hminic linkers to form a 1D ladder-like polymer chain. The chelating ligand IP coordinated to the Cd(II) atom, and alternately attached to both sides of the ladder-like polymer chain. Adjacent chains are further bound together by strong intermolecular hydrogen bonds and face-To-face φφ interactions, resulting in the formation of a 3D supramolecular architecture. Furthermore, the thermal stability and luminescent properties of this complex and the free ligands have been investigated

Study of the processes χcJ → Ξ−Ξ¯+ and Ξ0Ξ¯0

Using 448.1 × 106 ψ(3686) decays collected with the BESIII detector at the BEPCII e+e− storage rings, the branching fractions and angular distributions of the decays χcJ → Ξ−Ξ¯¯¯¯+ and Ξ0Ξ¯¯¯¯0 (J = 0, 1, 2) are measured based on a partial-reconstruction technique. The decays χc1 → Ξ0Ξ¯¯¯¯0 and χc2 → Ξ0Ξ¯¯¯¯0 are observed for the first time with statistical significances of 7σ and 15σ, respectively. The results of this analysis are in good agreement with previous measurements and have significantly improved precision