Crystal structures of an azobenzene-bridged aza-18-crown-6 cryptand and a sodium complex thereof

We report the single-crystal X-ray diffraction structures of the azobenzene-bridged aza-18-crown-6 cryptand 7,16-[3,3′-(diazene-1,2-diyl)bis(1,3-phenylenecarbonyl)]-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane, C 26 H 32 N 4 O 6 , 1 , and its sodium complex poly[[{μ-7,16-[3,3′-(diazene-1,2-diyl)bis(1,3-phenylenecarbonyl)]-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane}bis{tetrakis[3,5-bis(trifluoromethyl)phenyl]borato}disodium] benzene disolvate], {[Na 2 (C 32 H 12 F 24 B) 2 (C 26 H 32 N 4 O 6 )]·2C 6 H 6 } n . The free ligand 1 crystallizes in space group P 2 1 / n and adopts an elongated strain-distorted crown conformation with a slightly twisted azobenzene unit. In contrast, 2 [obtained with sodium tetrakis-3,5-bis(trifluoromethyl)phenyl borate (NaBArF)] crystallizes in space group P 1 and features multiple Na + centers that assemble into a three-dimensional network in the solid state. Hirshfeld surface analysis was used to provide a complementary, quantitative description of the dominant intermolecular contacts governing the crystal packing.