Designing Chiral, Pro-Polar Structures for Observing Ferroelectricity: Molecular Analogue of KNO₃

Abstract

Observation and creation of a pro-chiral center is a prerequisite in chemical synthesis for generating chiral structures. On the other hand, temporary and reversible generation of chiral or polar structures using physical forces such as electricity is a need of present technology for observing nonlinear behavior. Thus, one can synthesize a pro-polar structure, akin to a pro-chiral center using chemical interactions, for facilitating physical forces in generating chiral/polar structures, a novel way for designing molecular materials. At room temperature, the structure of KNO 3 and anilinium nitrate (AnHNO 3 ) is centrosymmetric, although the latter showed molecular properties in the form of distinct helical NH•••O hydrogen bonding to generate a dipole moment, which in turn gets canceled due to the formation of antiparallel double helical chains. We could separate these helical chains of NH•••O hydrogen bonding, by chemical design, synthesis of analogues molecules (para-ethyl anilinium nitrate), and crystallization through a gel as well slow evaporation technique, to obtain a pro-polar and chiral structure with molecular ferroelectric behavior. Thus, creation of a pro-polar structure, presented here by modifying the cation in KNO 3 to observe room temperature ferroelectric behavior, will help in designing novel molecular ferroelectric materials.

Bis(3,5-lutidine)alkyl Dications and Their Use in the Fabrication of Organic–Inorganic 2D Polypseudorotaxane by Templated Self-Assembly

“…For example, the Leigh , and Aida groups demonstrated that inorganic nanocluster “wheels” are penetrable by finite or infinite organic “axles”, and more recently a tetrasilver cluster was shown to reside in a polypyridine macrocycle, forming a hybrid inorganic–organic pseudorotaxane; Dan Li’s Group reported a 1D hybrid polypseudorotaxane composed of mechanically interlocked infinite inorganic “axles” and finite organic “wheels” . This kind of hybrid polypseudorotaxane material not only combines the respective beneficial characteristics of inorganic and organic components, but also often exhibits unique properties that exceed what would be expected for a simple mixture of the components. − However, the rational design and fabrication of 2D polypseudorotaxane remains a great challenge, and few examples have been reported. − Cartoon representations of rotaxane and 1D and 2D polypseudorotaxane are shown in Figure .…”