Crystal structures of two solvates of (18-crown-6)potassium acetate

Abstract

The crystal and molecular strutures of two solvated forms of [K(18c6)]OAc (18c6 = 18-crown-6 = 1,4,7,10,13,16-hexaoxacyclooctadecane and OAc = acetate) were determined by single-crystal X-ray diffraction, namely (acetato-κ2O,O′)(1,4,7,10,13,16-hexaoxacyclooctadecane-κ6O)potassium dihydrate, [K(CH3COO)(C12H24O6)]·2H2O (1) and (acetato-κ2O,O′)aqua(1,4,7,10,13,16-hexaoxacyclooctadecane-κ6O)potassium acetic acid monosolvate [K(CH3COO)(C12H24O6)(H2O)]·CH3COOH (2). In both compounds, the acetate anion is bonded to the potassium ion in a chelating fashion and the metal atom is consequently slightly displaced from the O6 plane of the crown ether. In the crystals, O—H...O hydrogen bonds lead to a polymeric ladder structure in the dihydrate 1, while the acetic acid hydrate 2 features inversion dimers.

Keywords

• crystal structure
• potassium
• crown ether
• 18-crown-6
• acetate
• hydrate
• hydroacetate
• hydrogen bridge bonds