A Water Rich Crystalline Hydrate Formed by 1,4,7,10-Tetraazacyclododecane, Siliconhydrofluoric Acid and Water: Structure and Properties

Abstract

Novel complementary associations have been found in a crystalline ternarycomplex of the macrocyclic tetramine, [12]aneN4 (e.g. =1,4,7,10-tetraazacyclododecane, cyclen, L), hexafluorosilicate ions andwater (I). The final compound belongs to the host—guest type with themacrocycle as the host (H), the inorganic entity as a guest (G) and watermolecules. It was characterized by X-ray techniques, IR spectroscopy andthermogravimetric study. X-ray crystal analysis revealed that the structureis built of the charged entities, with a 3D-network uniting thequadriprotonated form of the macrocycle, hexafluorosilicate as counterionsand lattice water molecules viaN—H+...F-,N—H+...O(w),OH...F- and O—-H(w)...O(w)hydrogen bonds. The overall complex stoichiometry comprises fourSiF62- anions and seven water molecules per two[LH4]4+ cations. Crystals of (I) are monoclinic,space group P21/n with a = 14.585(3), b = 16.384(2), c =16.500(3) A, β = 92.84(3)°, V = 3938(1)A3 and Z = 8 forC8H31F12N4O3.5Si2.