Synthesis, crystal structure, and thermochemical behavior of the guest-host complex [(LH2)(BF4)2 H2O] (L = racemate-5,7,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane)

The interaction between BF3 (C2H5)2Oand a racemate of 5,7,7,12,12,14-hexamethyl-l,4,8,11-tetraazacyclotetradecane (L) in the presence of air moisture leads to the complex [(LH 2) BF4)2 - H2O] (I), whose structure was determined by X-ray structure analysis and confirmed by thermogravimetric data. The crystals are monoclinic, C16H40B2F8N4O, space group P21ln, a-25.570(7), b = 11.231(5), c = 8.715(4) a, α = 97.32(3)‡, Z = 4, the final R value is 0.0753 for 2800 unique reflections. The structure is built from the double-charged organic cations of the tetraazamacrocycle, tetrafluoroborate anions, and water molecules (1:2:1) linked by a system of hydrogen bonds of NH...F, NH...O, and OH...F type, in which all the four macrocycle nitrogens perform the function of proton donors. The macrocycle in the complex has approximately C2 symmetry.