查看更多>>摘要：Regulating spin crossover(SCO)behavior,especially controlling the spin transition steps,is an important scientific issue,mainly be-cause people aim to control spin bistability and multistability.Presently,SCO bistability can be regulated by changing the lig-and-modifying species,non-coordinated anions,guest molecules,and metal-ion dopant.However,the control of multistability is ex-tremely challenging,especially in Fe(Ⅲ)SCO compounds.Here,we report that[FeⅢ(H-5-Br-thsa)(5-Br-thsa)]·H2O(5-Br-thsa=(5-bromo-2-hydroxybenzylidene)hydrazinecarbothioamide),a compound we have reported before,exists in two polymorphic forms:polymorph 1 exhibits three-step SCO,and polymorph 2 shows five-step SCO,with multi-step SCO behavior effectively regulated by polymorphism.According to single-crystal and powder X-ray diffractometry,polymorphs 1 and 2 crystallize in different space groups during their spin transitions,with two-step symmetry breaking observed(Pbcn → Pnc2 → Pbcn for polymorph 1;P21/n → Pn →P21/n for polymorph 2).We realized that the behavior of these two polymorphs depends significantly on the structure,including(ⅰ)the average Fe-N bond distance,(ⅱ)deformation of octahedral FeⅢ atoms,and(ⅲ)distinct crystal packing,which account for the large differences observed in magnetic properties.
查看更多>>摘要：Organofluorine compounds are central in synthetic chemistry,medicinal chemistry and material chemistry.In this review,we sum-marize the investigations on the synthesis of organofluorine compounds with acylsilanes.For the non-fluorinated acylsilanes,the in situ generation of difluoroenoxysilanes from the reactions of the acylsilanes with trifluoromethylation reagents is the major pathway,leading to the facile preparation of various a,a-difluoroketones.For the fluoroalkylacylsilanes,apart from the in situ generation of difluoroenoxysilanes through anion Brook rearrangement,radical Brook rearrangement of the photoexcited acylsilanes and the se-lective control of reactivities of the biradicals pave the way for the synthesis of a variety of organofluorine compounds.In general,most of these reactions gave racemic products,and the asymmetric synthesis of organofluorine compounds with acylsilanes is still rare,which would be a future direction of this field.
查看更多>>摘要：Sensing the chirality of molecules is of great importance to fields such as enantioselective synthesis,pharmaceutical industry,and biomedicine.Plasmonic nanoparticles are ideal candidates for molecular sensing due to their inherent plasmonic properties that sig-nificantly enhance their sensitivity to surrounding molecules.Developing plasmonic nanoparticle-molecule complexes for chirality sensing has drawn enormous attention in recent years due to their intriguing properties and potential applications.Thus,in this re-view,we believe it is timely to circumnavigate the rational design of plasmonic nanoparticle-molecule complexes and widen the scope of their emerging applications in chirality sensing.First,we present different fundamental mechanisms for plasmon-based chirality that are built on the system of plasmonic nanoparticle-molecule complexes.Second,we review the typical applications of plasmonic nanoparticle-molecule complexes in chirality sensing.Third,we discuss the emerging biomedical applications that the plasmon-based chirality has attracted enormous interest.Finally,we provide an outlook on the challenges and opportunities in the field of plasmonic approaches for chirality sensing.
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