Ferroelectricity is essential to many forms of current technology, ranging from sensors and
actuators to optical or memory devices. In this circumstance, organic ferroelectrics are of
particular importance because of their potential application in tomorrow's organic devices,
and several pure organic ferroelectrics have been recently developed. However, some
problems, such as current leakage and/or low working frequencies, make their application
prospects especially for ferroelectric memory (FeRAM) not clear. Here, we describe the
molecule-displacive ferroelectricity of supramolecular adducts of tartaric acid and
1,4-diazabicyclo[2.2.2]octane N,N′-dioxide. The adducts show large spontaneous
polarization, high rectangularity of the ferroelectric hysteresis loops even at high
operation frequency (10 kHz), and high performance in polarization switching up to 1 ×
106 times without showing fatigue. It opens great perspectives in terms of
applications, especially in organic FeRAM.
The development of highly efficient CO2 separation materials is very important for environmental preservation and energy conservation. Crystalline porous coordination polymers (PCPs)/metal–organic frameworks are one of a number of promising types of porous materials for CO2 separation because of their controllable pore size, shape and surface function. Simultaneously, the unique structural flexibility of PCPs affords both high CO2 selectivity and inexpensive regeneration. However, this family of materials suffers from the coexistence of water that destroys the framework of PCPs and its adsorption in the pores is greater than that of CO2, which results in a deterioration in CO2‐separation performance. Herein, a flexible and hydrophobic CuII PCP that is stable towards water has been designed and synthesised. This PCP has extremely high adsorption selectivity for CO2 over CH4, derived from its structural flexibility. Furthermore, the obtained water‐tolerant flexible PCP, under CO2/CH4 mixed‐gas conditions, exhibits highly selective CO2 adsorption over CH4, even in the presence of water.
A single crystal of (3-fluoro-4-methoxyanilinium)+([18]crown-6)[MnIICrIII(oxalate)3]−(CH3OH)2 had the space group Cc owing to the arrangement of the 3-fluoro-4-methoxyanilinium+ cation with C1 symmetry and, therefore, was pyroelectric. A ferromagnetic transition at 5.5 K was observed, which originated from the two-dimensional honeycomb structure of the [MnIICrIII(oxalate)3]− anion.
Metal−organic network structure based on oxalate bridges {[Mn II Cr III (oxalate) 3 ] − } ∞ and supramolecular cations (H 2 PPD 2+ )(benzo[18]crown-6) 2 [MnCr(oxalate) 3 ]-(CH 3 OH)(CH 3 CN) 2 (1) and (o-FAni + ) 2 (DCH[18]crown-6) 2 [Mn(CH 3 OH)Cr(oxalate) 3 ][MnCr(oxalate) 3 ](CH 3 OH)(2), where H 2 PPD 2+ , o-FAni + , and DCH[18]crown-6 denote p-phenylenediammonium 2+ , o-fluoroanilinium + , and cis-syn-cisdicyclohexano[18]crown-6, respectively, were synthesized. The crystal structure of 1 was the combination of [Mn(Λ)-Cr(Λ)(oxalate) 3 ] − and [Mn(Λ)Cr(Δ)(oxalate) 3 ] − , whereas that of crystal 2 was the combination of [Mn(Λ)(CH 3 OH)-Cr(Δ)(oxalate) 3 ] and [Mn(Λ)Cr(Δ)(oxalate) 3 ]. Large flexible supramolecular cations provide the three-dimensional structure of {[Mn II Cr III (oxalate) 3 ] − } ∞ , which is different from the twodimensional honeycomb structure often observed for {[Mn II Cr III (oxalate) 3 ] − } ∞ complexes. Temperature-dependent magnetic susceptibilities of the complexes 1 and 2 exhibited ferromagnetic behaviors following the Curie−Weiss law (C = 11.5 cm 3 K mol −1 , θ = 13.0 K for 1; C = 4.14 cm 3 K mol −1 , θ = 12.3 K for 2).
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.