X-ray crystal structure determination of a complex between 4 ',5 '-dibromobenzo-12-crown-4 and NaBr

The crystal structure of a complex between 4',5'-dibromobenzo-12-crown-4(4' ,5'-dibromo-B12C4) and NaBr with the component ratio ligand : Na : Br : H2O = 2 : 1 : 1 : 2 is studied by X-ray diffraction, The crystallographic para meters of single crystals are a = 8.281(2), b = 12.199(3), and c = 16.862(5 ) Angstrom; alpha = 73.73(2)degrees, beta = 86.57(2)degrees, and gamma = 72 .42(2)degrees; V = 1558.2(8) Angstrom(3); P-calcd = 2.17 g/cm(3); Z = 2; an d sp. gr. P (1) over bar. The structure is solved by the direct method and refined by the least-squares technique to R = 0.056. All the oxygen atoms o f the macrocycles of two ligand molecules are involved in the coordination with the sodium ion to form a sandwich biligand cation. The charge neutrali ty of the crystal is provided by cocrystallization with the bromine ions.