Inorganic-organic or hybrid perovskite materials,which are the complementary counterparts of pure inorganic perovskites,can provide many new opportunities in the researches of phase transitions,critical phenomena,and ...Inorganic-organic or hybrid perovskite materials,which are the complementary counterparts of pure inorganic perovskites,can provide many new opportunities in the researches of phase transitions,critical phenomena,and relevant properties,as they combine the characteristics of inorganic and organic components.Therefore,the hybrid perovskites of ammonium metal formate framework are very promising,and their properties have been found to be strongly dependent on the characteristics of the constituent metal ions and/or ammonium ions.Herein,we used solid solution strategies,borrowed from solid state chemistry,to investigate the anisotropic diluted magnetic hybrid perovskite system of[CH_(3)NH_(3)][CoxZn1−x(HCOO)3],wherein the B-sites are occupied by the mixed metal ions of Co^(2+)and Zn^(2+).The solid solution compounds of this series in the range x=0–1(or the molar percent Co%=0–100%)were successfully prepared using conventional solution chemistry methods.The resulting compounds were demonstrated to be iso-structural by using both single-crystal and powder X-ray diffraction analyses.The solid solution crystals belong to the orthorhombic space group Pnma,with the cell parameters being a=8.3015(2)–8.3207(3)Å,b=11.6574(4)–11.6811(5)Å,c=8.1315(3)–8.1427(4)Å,and V=787.89(5)–790.98(7)Å3.The perovskite structure consists of a simple cubic anionic metal-formate framework and CH_(3)NH_(3)+cations which are located in the framework cavities,with N―H···O hydrogen bonds formed between the framework and the cation.The members of this series showed negligible changes(<0.4%)in their respective lattice and structural parameters.Thus,the prepared solid solution compounds constitute good molecule-based examples for the study of magnetic dilution under almost the same structural parameters and molecular geometries.Upon dilution,the magnetization per mole of Co at low temperatures and low fields was suppressed by the magnetic anisotropy of Co^(2+)and gradual destruction of the large spin canting between coupled Co^(2+)ions,in contrast to the magnetization enhancement observed in the isotropic diluted system of[CH_(3)NH_(3)][MnxZn1−x(HCOO)3]with the same perovskite structure.The percolation limit was estimated as(Co%)P=27(1)%(or xP=0.27(1))from the magnetic data,which was slightly lower than that predicted by the percolation theory for a simple cubic lattice(31%);this trend was due to the strong magnetic anisotropy of the present system.In addition,rare incommensurate phase transitions were primarily detected below~120 K for the pure Co and Zn members,which may also affect the magnetic properties of the materials.展开更多
Anti-inflammatory therapy is often considered as an effective way to treat sepsis,but it only relives systemic inflammation without protecting the damaged vital organs.In our present study,we found that,lung is the mo...Anti-inflammatory therapy is often considered as an effective way to treat sepsis,but it only relives systemic inflammation without protecting the damaged vital organs.In our present study,we found that,lung is the most vulnerable organ compared to other vital organs in the progression of sepsis,characterized by excessively inflammatory response and activated platelet accumulation.Herein,an activated platelet-targted nanoparticle(P-TPNP-pD)was designed to facilitate drug delivery to sepsis-damaged lungs.Because of the high expression of P-selectin on activated platelets,P-TPNPpD,modified with a P-selectin-targeting peptide(PTP),could target activated platelets and significantly accumulate in sepsis-damaged lungs via effective Pselectin-PTP binding.Meanwhile,due to the low pH of inflammation sites in sepsis-damaged lungs,nanoparticles with polydopamine(pD)modification could release anti-inflammatory drugs(Piceatannol,PIC)in a pH-responsive manner.However,the anti-inflammatory treatment was insufficient to alleviate lung injury in sepsis.Aggregation of activated platelets in the lungs induced by sepsis often leads to the formation of thrombosis,resulting in pulmonary dysfunction.Therefore,we further co-loaded anti-thrombotic drugs(Ticagrelor,TIC)into those nanoparticles.The dual antiinflammatory/anti-thrombotic therapy could profoundly achieve lung protection in a sepsis mouse model with less infiltration of neutrophils and platelets,and reduce the risk of crosstalk between neutrophils and platelets simultaneously.This work provided proof-of-concept strategy to relive systemic inflammation and protect the vital organs of lung from inflammation and thrombosis in the progression of sepsis.展开更多
We report here a new class of ammonium metal-formate frameworks of[NH_(2)NH_(3)][M(HCOO)_(3)](M=Mn^(2+),Zn^(2+),Co^(2+)and Mg^(2+))incorporating hydrazinium as the cationic template and component.The perovskite Mn and...We report here a new class of ammonium metal-formate frameworks of[NH_(2)NH_(3)][M(HCOO)_(3)](M=Mn^(2+),Zn^(2+),Co^(2+)and Mg^(2+))incorporating hydrazinium as the cationic template and component.The perovskite Mn and Zn members possess anionic 4^(12)·6^(3)metal-formate frameworks with cubic cavities occupied by the NH_(2)NH_(3)^(+)cations,while the Co and Mg members have chiral 49·66 metal-formate frameworks,with chiral hexagonal channels accommodating NH_(2)NH_(3)+cations.On heating,the Mn and Zn members undergo phase transitions around 350 K.The structures change from low temperature(LT)polar phases in Pna2_(1)to high temperature(HT)non-polar phases in Pnma,due to the thermally activated librational movement of the NH_(2)end of the NH_(2)NH_(3)^(+)in the cavity and significant framework regulation.The Co and Mg members in LT belong to non-polar P2_(1)2_(1)2_(1),are probably antiferroelectric,and they show phase transitions at 380 K(Co)and 348 K(Mg),and the structures change to polar HT phases in P6_(3),triggered by the order-disorder transition of the cation from one unique orientation in LT to three of trigonally-disorder state in HT.Accompanying the phase transitions,which are ferro-to para-electric for Mn and Zn members while antiferro-to ferro-electric for Co and Mg,prominent anisotropic thermal expansions including negative ones,and dielectric anomalies,are observed.The spontaneous polarization values are estimated at 3.58(Mn,110 K),3.48(Zn,110 K),2.61(Co,405 K)and 3.44(Mg,400 K)μC cm^(-2),respectively,based on the positive and negative charge separations in the polar structures.The structure-property relevance is established based on the order-disorder transitions of NH2NH3+and the conformity and adaptability of the metal-formate frameworks to match such order-disorder alternations.The Mn and Co members show spin-canted antiferromagnetic long-range-ordering,with Néel temperatures of 7.9 K and 13.9 K,respectively.Therefore,the two members show coexistence of electric and magnetic orderings in the low temperature region,and they are possible molecule-based multiferroics.展开更多
文摘Inorganic-organic or hybrid perovskite materials,which are the complementary counterparts of pure inorganic perovskites,can provide many new opportunities in the researches of phase transitions,critical phenomena,and relevant properties,as they combine the characteristics of inorganic and organic components.Therefore,the hybrid perovskites of ammonium metal formate framework are very promising,and their properties have been found to be strongly dependent on the characteristics of the constituent metal ions and/or ammonium ions.Herein,we used solid solution strategies,borrowed from solid state chemistry,to investigate the anisotropic diluted magnetic hybrid perovskite system of[CH_(3)NH_(3)][CoxZn1−x(HCOO)3],wherein the B-sites are occupied by the mixed metal ions of Co^(2+)and Zn^(2+).The solid solution compounds of this series in the range x=0–1(or the molar percent Co%=0–100%)were successfully prepared using conventional solution chemistry methods.The resulting compounds were demonstrated to be iso-structural by using both single-crystal and powder X-ray diffraction analyses.The solid solution crystals belong to the orthorhombic space group Pnma,with the cell parameters being a=8.3015(2)–8.3207(3)Å,b=11.6574(4)–11.6811(5)Å,c=8.1315(3)–8.1427(4)Å,and V=787.89(5)–790.98(7)Å3.The perovskite structure consists of a simple cubic anionic metal-formate framework and CH_(3)NH_(3)+cations which are located in the framework cavities,with N―H···O hydrogen bonds formed between the framework and the cation.The members of this series showed negligible changes(<0.4%)in their respective lattice and structural parameters.Thus,the prepared solid solution compounds constitute good molecule-based examples for the study of magnetic dilution under almost the same structural parameters and molecular geometries.Upon dilution,the magnetization per mole of Co at low temperatures and low fields was suppressed by the magnetic anisotropy of Co^(2+)and gradual destruction of the large spin canting between coupled Co^(2+)ions,in contrast to the magnetization enhancement observed in the isotropic diluted system of[CH_(3)NH_(3)][MnxZn1−x(HCOO)3]with the same perovskite structure.The percolation limit was estimated as(Co%)P=27(1)%(or xP=0.27(1))from the magnetic data,which was slightly lower than that predicted by the percolation theory for a simple cubic lattice(31%);this trend was due to the strong magnetic anisotropy of the present system.In addition,rare incommensurate phase transitions were primarily detected below~120 K for the pure Co and Zn members,which may also affect the magnetic properties of the materials.
基金supported by the Regional Innovation and Development Joint Fund of National Natural Science Foundation of China(No.U22A20356).
文摘Anti-inflammatory therapy is often considered as an effective way to treat sepsis,but it only relives systemic inflammation without protecting the damaged vital organs.In our present study,we found that,lung is the most vulnerable organ compared to other vital organs in the progression of sepsis,characterized by excessively inflammatory response and activated platelet accumulation.Herein,an activated platelet-targted nanoparticle(P-TPNP-pD)was designed to facilitate drug delivery to sepsis-damaged lungs.Because of the high expression of P-selectin on activated platelets,P-TPNPpD,modified with a P-selectin-targeting peptide(PTP),could target activated platelets and significantly accumulate in sepsis-damaged lungs via effective Pselectin-PTP binding.Meanwhile,due to the low pH of inflammation sites in sepsis-damaged lungs,nanoparticles with polydopamine(pD)modification could release anti-inflammatory drugs(Piceatannol,PIC)in a pH-responsive manner.However,the anti-inflammatory treatment was insufficient to alleviate lung injury in sepsis.Aggregation of activated platelets in the lungs induced by sepsis often leads to the formation of thrombosis,resulting in pulmonary dysfunction.Therefore,we further co-loaded anti-thrombotic drugs(Ticagrelor,TIC)into those nanoparticles.The dual antiinflammatory/anti-thrombotic therapy could profoundly achieve lung protection in a sepsis mouse model with less infiltration of neutrophils and platelets,and reduce the risk of crosstalk between neutrophils and platelets simultaneously.This work provided proof-of-concept strategy to relive systemic inflammation and protect the vital organs of lung from inflammation and thrombosis in the progression of sepsis.
基金supported by the NSFC(grants 21171010,21290170,21290171)the National Basic Research Program of China(grant 2009CB929403).
文摘We report here a new class of ammonium metal-formate frameworks of[NH_(2)NH_(3)][M(HCOO)_(3)](M=Mn^(2+),Zn^(2+),Co^(2+)and Mg^(2+))incorporating hydrazinium as the cationic template and component.The perovskite Mn and Zn members possess anionic 4^(12)·6^(3)metal-formate frameworks with cubic cavities occupied by the NH_(2)NH_(3)^(+)cations,while the Co and Mg members have chiral 49·66 metal-formate frameworks,with chiral hexagonal channels accommodating NH_(2)NH_(3)+cations.On heating,the Mn and Zn members undergo phase transitions around 350 K.The structures change from low temperature(LT)polar phases in Pna2_(1)to high temperature(HT)non-polar phases in Pnma,due to the thermally activated librational movement of the NH_(2)end of the NH_(2)NH_(3)^(+)in the cavity and significant framework regulation.The Co and Mg members in LT belong to non-polar P2_(1)2_(1)2_(1),are probably antiferroelectric,and they show phase transitions at 380 K(Co)and 348 K(Mg),and the structures change to polar HT phases in P6_(3),triggered by the order-disorder transition of the cation from one unique orientation in LT to three of trigonally-disorder state in HT.Accompanying the phase transitions,which are ferro-to para-electric for Mn and Zn members while antiferro-to ferro-electric for Co and Mg,prominent anisotropic thermal expansions including negative ones,and dielectric anomalies,are observed.The spontaneous polarization values are estimated at 3.58(Mn,110 K),3.48(Zn,110 K),2.61(Co,405 K)and 3.44(Mg,400 K)μC cm^(-2),respectively,based on the positive and negative charge separations in the polar structures.The structure-property relevance is established based on the order-disorder transitions of NH2NH3+and the conformity and adaptability of the metal-formate frameworks to match such order-disorder alternations.The Mn and Co members show spin-canted antiferromagnetic long-range-ordering,with Néel temperatures of 7.9 K and 13.9 K,respectively.Therefore,the two members show coexistence of electric and magnetic orderings in the low temperature region,and they are possible molecule-based multiferroics.
