Synthesis, structure and spectrum studies on Na4(LM)2(H2O)12 (H2LM=lumazine)

Single crystal of lumazine-sodium complex Na4(LM)2(H2O)12 (lumazine=pteridine-2,4(1H,3H)-dione) has been synthesized, and its structure has been determined with XRD method. It crystallizes in the monoclinic system (space group C2/c) with cell dimensions: a=26.842(7), b=6.6066(17), c=17.942(4) Å, β=126.056(4)°. The structure was solved from 2265 independent reflections with I>2σ(I). The final R [I>2σ(I)] was 0.0520 for 219 parameters. In its structure, every two Na2(LM)(H2O)6 units are connected to each other by two water molecules coordinated to Na(1) and Na(1A) separately forming a Na(1)-O(1)-Na(1A)-O(3) plane quadrangle coordination structure. And the formed dimers are linked by hydrogen bonds stacking the three-dimensional crystal structure. In IR spectra, the characteristic vibrations of υ(CO) at 1683 and 1640 cm−1 are red-shifted, compared with those of Lumazine (υCO 1716, 1701 cm−1). The fluorescence properties of solid Na4(LM)2(H2O)12 is determined at room temperature, the maximal excitation peak appeared at 473 nm, and the corresponding emission peak at 560 nm.