Crystal Structures of N,N’-bis(5-Dodecyloxytropon-2-yl)piperazine and N,N’-bis(4-Butoxyphenyl)piperazine

Abstract

The crystal structures of N,N'-bis(5-dodecyloxytropon-2-yl)piperazine (1) and N,N'-bis(4-butoxyphenyl)piperazine (2) were analyzed by X-ray crystallography. The molecules of 1 and 2 sit on a center of symmetry such that the two aromatic rings are in an anti conformation with respect to one another across the piperazine ring. The molecules (1, 2) form a tilted layer structure via intermolecular C-H•••O and C-H•••π interactions in 1 and intermolecular C-H•••O, C-H•••N, and C-H•••π interactions in 2. The synthesis, elucidation of crystal structures and investigation of physical properties of new liquid crystals are important for studying the relationship between molecular structures and mesophases. 1-6 Numerous studies have been dedicated to the structural investigation and the determination of the molecular aggregation mechanism. X-Ray crystallographic analysis plays an important role in obtaining information about intermolecular interactions controlling mesophases. The development of new type of crystals is an important and challenging subject from theoretical and practical view, because liquid crystalline materials are widely applied in communication and information processing systems. Recently

Crystal Structure of 5-[4-(Dodecyloxy)benzoyloxy]-2-(hexadecanoyloxy)tropone

“…3,4 For the intermolecular C-H•••π interaction, the H7•••C27 iii distance (symmetry code: (iii) -x, 1-y, 2-z) is 2.722 Å, which agrees with the distance for this type of interaction (2.8 -3.1 Å). 3,4 These intermolecular C-H 5.9(4) C5-O4-C24-C25 -170.4(2) C24-O4-C5-C4 -89.9(3) C24-O4-C5-C6 91.3(3) C31-O6-C28-C27 9.9(4) C31-O6-C28-C29 -169. 4(2) O4-C24-C25-C26 -11.5(4) O4-C24-C25-C30 167.4(2) O5-C24-C25-C26 172.4 3O5-C24-C25-C30 -8.8(5)…”

“…3,4 These intermolecular C-H 5.9(4) C5-O4-C24-C25 -170.4(2) C24-O4-C5-C4 -89.9(3) C24-O4-C5-C6 91.3(3) C31-O6-C28-C27 9.9(4) C31-O6-C28-C29 -169. 4(2) O4-C24-C25-C26 -11.5(4) O4-C24-C25-C30 167.4(2) O5-C24-C25-C26 172.4 3O5-C24-C25-C30 -8.8(5)…”

Crystal Structure of <i>N,N</i>′-Bis(5-butoxytropon-2-yl)piperazine

“…Recently, we prepared liquid crystals with a N,N′-bis(tropon-2-yl)piperazine core. [3][4][5] N,N′-Bis(5-alkoxytropon-2-yl)piperazines had a phase sequence of crystals-smectic C phase-isotropic for n = 8 -16, while N,N′-bis(5-buthoxytropon-2-yl)piperazine (1) (Fig. 1) was not mesomorphic.…”