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1.
Organic–inorganic hybrid perovskite-type multiferroics have attracted considerable research interest owing to their fundamental scientific significance and promising technological applications in sensors and multiple-state memories. The recent achievements with divalent metal dicyanamide compounds revealed such malleable frameworks as a unique platform for developing novel functional materials. Herein, two 3D organic–inorganic hybrid perovskites [Et3P(CH2)2F][Mn(dca)3] ( 1 ) and [Et3P(CH2)2Cl][Mn(dca)3] ( 2 ) (dca=dicyanamide, N(CN)2) are presented. Accompanying the sequential phase transitions, they display a broad range of intriguing physical properties, including above room temperature ferroelastic behavior, switchable dielectricity, and low-temperature antiferromagnetic ordering (Tc=2.4 K for both 1 and 2 ). It is also worth noting that the spontaneous strain value of 1 is far beyond that of 2 in the first ferroelastic phase, as a result of the precise halogen substitution. From the point view of molecular design, this work should inspire further exploration of multifunctional molecular materials with desirable properties.  相似文献   
2.
Four linear trinuclear transition metal complexes have been prepared and characterized. The complexes [MII(MeOH)4][FeIII(L)2]2·2MeOH (M = Fe (1) or Ni (2)), [CoII(EtOH)2(H2O)2][FeIII(L)2]2·2EtOH (3), and [MnII(phen)2][MnIII(L)2]2·4MeOH (4) (H2L = ((2-carboxyphenyl)azo)-benzaldoxime, phen = 1,10-phenanthroline) possesses a similar synanti carboxylate-bridged structure. The terminal Fe(III) or Mn(III) ions are low spin, and the central M(II) ions are high spin. Magnetic measurements show that antiferromagnetic interactions were present between the adjacent metal ions via the synanti carboxylate bridges. The antiferromagnetic coupling between low-spin Fe(III) and Ni(II) is unusual, which has been tentatively assigned to the structural distortion of Fe(III).  相似文献   
3.
刘彩明  郝项 《无机化学学报》2020,36(6):1105-1112
用溶剂热方法合成了2个新的3d-4f异金属四核簇合物:[Zn2Ln2(salen)2(CO2PyCH2O)2(MeOH)2](ClO42·2MeOH(Ln=Dy(1),Tb(2);H2salen=N,N'-双(3-甲氧基水杨基)-1,3-二氨基丙烷;HCO2PyCH2OH=6-羧基吡啶-2-甲醇)。它们是由锌(Ⅱ)Schiff碱构筑模块和6-羧基吡啶-2-甲醇辅助配体组装而成的Zn-Ln2-Zn型簇合物。磁性测量表明稀土离子间存在铁磁性相互作用。Zn2Dy2配合物1在2 000 Oe直流磁场下显示出磁弛豫行为;而Zn2Tb2配合物2不但有磁场导致的磁弛豫行为,而且还具有荧光性质。  相似文献   
4.
利用超声波辅助萃取(USE)技术,联合固相萃取(SPE)净化浓缩以及液相色谱-电喷雾串联质谱(LC-ESI-MS/MS)技术,建立了城市污泥和河流底泥中微量-痕量大环内酯类、磺胺类抗生素、甲氧苄胺嘧啶和氯霉素的多目标定量分析方法.样品经USE提取,SPE净化后,用LC-ESI-MS/MS检测.选择C18为分析柱,甲醇、5 mmol/L醋酸铵和0.1%甲酸混合溶液为流动相,选择在ESI正电离源下多反应监测(MRM)模式检测.对比了USE和加速溶剂萃取(ASE)对抗生素的萃取效率,优化了萃取条件.结果表明: USE和ASE对所选抗生素的萃取效率相当; 而50%甲醇溶液在酸性条件下(pH 2)萃取效率最好.抗生素的方法检出限为2.2~66.9 ng/g(干重,下同); 回收率介于74.7%~111.8%之间; 相对标准偏差小于10.6%.应用此方法在广州某污水处理厂脱水污泥及某河涌底泥中检测到磺胺二甲基嘧啶、克拉霉素、脱水红霉素及罗红霉素等多种抗生素,含量为6.8~125.6 ng/g.  相似文献   
5.
建立了生物样品中9种微量内分泌干扰物(EDCs)的多目标分析方法.采用旋涡振荡-超声波辅助萃取,结合凝胶渗透色谱(GPC)除去大分子有机物干扰,再经硅胶柱层析进一步净化,最后应用超高效液相色谱-串联质谱(UHPLC-MS/MS)检测.GPC采用乙酸乙酯-环己烷混合溶液(1:1,V/V)为流动相,选择12~28 mL为目标化合物馏分的收集段;质谱采用电喷雾离子源正离子模式和大气压化学电离源负离子模式,数据采集为多重反应监测模式.方法回收率为65.2%~118.0%,定量限为0.1~9.7 ng/g dw(干重).采用本方法初步分析了珠江水系鲤鱼脊肉中的内分泌干扰污染物,结果表明,除均二苯腺和三氯卡班未被检出外,其它内分泌干扰污染物的含量为0.1~22.6 ng/g dw.  相似文献   
6.
A novel 2D metamagnetic compound composed of ferromagnetic Co(II) chains exhibits the intrinsic slow dynamics of single-chain magnets in the antiferromagnetic ordered phase and in the field-induced ferromagnetic phase.  相似文献   
7.
Six new carbonate-bridged Zn2Ln2 cluster complexes derived from salen-type Schiff base ligands [H2La = N, N′-bis(3-methoxysalicylidene)-1,3-diaminopropane and H2Lb = N, N′-bis(3-methoxysalicylidene)- 1,2-diaminoethane] have been synthesized. The bis-imine chain in Schiff base ligands have an obvious influence on the cluster complexes' structures, magnetic and luminescence properties. The carbonate bridging ligand exactly comes from autoimmobilization of carbon dioxide, which may mediate ferromagnetic coupling between Ln3+ ions, favoring magnetocaloric effects and single molecule magnet (SMM) properties. Complexes Zn2Dy2(μ3-CO3)2(La)2(NO3)2(MeOH)2 ( 1 ) and [Zn2Dy2(μ3-CO3)2(Lb)2(NO3)2]·2MeOH ( 2) show field-induced SMM properties; complexes Zn2Tb2(μ3-CO3)2(La)2(NO3)2(MeOH)2 ( 3 ) and [Zn2Tb2(μ3-CO3)2(Lb)2(NO3)2]·2MeOH ( 4 ) display both luminescence and field-induced SMM behaviors; while complexes [Zn2Gd2(μ3-CO3)2(La)2(NO3)2]·2MeOH ( 5 ) and [Zn2Gd2(μ3-CO3)2(Lb)2(NO3)2]·2MeOH ( 6 ) exhibit medium magnetic entropy changes, which are candidates for cryogenic molecular magnetic refrigerants.  相似文献   
8.
Two 3D coordination polymers of Mn(II) with azide and bifunctional zwitterionic ligands bearing both carboxylate and tetrazolate groups, 1-(carboxylatomethyl)-3-(5-tetrazolato)pyridinium (L(1)) and 1-(carboxylatoethyl)-4-(5-tetrazolato)pyridinium (L(2)), were synthesized, and structurally and magnetically characterized. They are formulated as [Mn(3)(L(1))(2)(N(3))(4)(H(2)O)(2)](n)·4nH(2)O (1) and [Mn(3)(L(2))(2)(N(3))(4)(H(2)O)(3)](n)·3.5nH(2)O (2). In both compounds, octahedral Mn(II) ions are linked by the mixed (μ(2)-EO-N(3))(μ(2)-syn,syn-COO)(μ(2)-N(2),N(3)-CN(4)) (CN(4) = tetrazolate and EO = end-on) triple bridges to give anionic linear trinuclear motifs. The motifs are connected through EE-N(3) (EE = end-to-end) bridges to give layers and chains in 1 and 2, respectively, and the cationic pyridinium spacers serve to interlink the layers or chains into three-dimensional frameworks with the α-Po and CdSO(4)-type topology, respectively. Magnetic studies demonstrated that the magnetic interactions within and between the trinuclear motifs, through the tricomponent and EE-N(3) bridges, respectively, are both antiferromagnetic in both compounds.  相似文献   
9.
用超声波辅助的方法合成得到了一个双核β-二酮镝配合物Dy2(Hpdm)2(dbm)4·2EtOH(1)(H2pdm=2,6-吡啶二甲醇,Hdbm=二苯甲酰甲烷)。单晶X-射线衍射结构分析表明双核镝(Ⅲ)结构单元通过2,6-吡啶二甲醇配体中去质子化的羟基氧原子桥联,每个镝(Ⅲ)离子呈现不规则的八面体配位构型。磁学性质研究表明,该配合物中镝(Ⅲ)离子之间存在着反铁磁性耦合作用, 但没有出现磁驰豫行为。  相似文献   
10.
The non-uniform chain manganese(III) complex constructed from EE-azido bridged MnIII3O units, [MnIII3O(Brppz)3-(MeOH)3(N3)] 2MeOH [1, Brppz = 3-(5-bromo-2-phenolate)-pyrazolate], is the first example of 1D azido-bridged coordination polymer showing both solvatomagnetic effect and spin-glass behavior.  相似文献   
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