An unprecedented A2MIMIIIX6-type double perovskite adopting a fully hexagonal BaNiO3-type structure, (piperidinium)2[KBiCl6], undergoes a 2/mF1̅ ferroelastic phase transition at 285 K with a spontaneous strain of 0.0615, arising from order-disorder...

The molecular iodine-catalyzed threecomponent reaction of amides or amide derivatives, paraformaldehyde and styrenes allows for the clean generation of allylamine derivatives in good yields and high regioselectivities. The reaction, forming water as the sole co-product, is an experimentally easy to conduct transformation in the absence of transition metals under mild conditions.

A domino desulfitative coupling/acylation/hydration process to synthesize C-2-(2-oxo-2phenylethylidene)-and N-3-carbonyl-substituted pyrimidines by unprecedented C À C and C À N crosscoupling reactions is described. This methodology couples 3,4-dihydropyrimidine-2-thiones and alkynes under modified Liebeskind-Srogl conditions using palladium acetate and copper(I) carboxylate. Remarkably the copper(I) carboxylates simultaneously act as desulfitative and acylation reagents in the reaction.

Molecular ferroelectrics have promising potential as next-generation flexible electronic materials by the advantage of flexibility, structural tunability, and easy processability. However, an obstacle in expanding their promising applications is effectively raising the ferroelectric transition temperature (Tc) necessary for practical applications, especially under high-temperature operating conditions. Herein, taking the advantage of a hydroxyl group that could form stronger hydrogen bonds to insert/tune host–guest and guest–guest interactions, we employed the 3-hydroxypyrrolidine cation to construct two new enantiomeric hexagonal perovskite ferroelectrics, (R)-3-OH-(C4H9N)[CdCl3] and (S)-3-OH-(C4H9N)[CdCl3]. Both of them undergo a ferroelectric phase transition from C2221 to P21 with a high Tc of 350 K, which is 110 K and 47 K higher than that of their parent compound (C4H10N)[CdCl3] (240 K) and F-substituted analogues (R/S)-3-F-(C4H9N)[CdCl3] (303 K), respectively. These findings well demonstrate that, besides the F-substitution strategy, an OH-substitution strategy provides an important and practical way in designing high-Tc ferroelectrics.

Two room-temperature polymorphic forms could be long-term stable yet easily interconvertible by switching the inter-cationic H-bonds in chiral molecular perovskites.