一种热响应介电开关型零维有机-无机杂化材料:(C_(3)H_(6)NH_(2))_(2)CoCl_(4)

A Thermally Responsive Dielectric Switchable Zero-Dimensional Organic-Inorganic Hybrid Material:(C_(3)H_(6)NH_(2))_(2)CoCl_(4)

刺激响应型智能材料,因其制备简单、结构多变、成本低廉,在信息存储和传感器等方面有着广阔的应用前景.本工作通过溶剂挥发法成功制备了一例新型零维有机-无机杂化材料:(C_(3)H_(6)NH_(2))_(2)CoCl_(4).差示扫描量热(DSC)和变温介电测试结果表明,(C_(3)H_(6)NH_(2))_(2)CoCl_(4)在347.7 K处发生可逆的结构相变,并伴随着明显的“台阶状”介电异常,表现出优良的介电开关特性.并通过变温单晶X-射线衍射(SCXRD)对相变机理进行研究,发现其经历了从P21/n空间群转变为Pnma空间群的结构变化,这主要源于(C_(3)H_(6)NH_(2))^(+)阳离子剧烈的有序-无序运动和(CoCl_(4))^(2–)阴离子微小的畸变作用.此外,本工作通过Crystal Explorer计算了阳离子周围的弱相互作用,并发现了阳离子之间的H...H相互作用和阴、阳离子之间的H...Cl相互作用是形成该杂化材料的主要原因.紫外-可见吸收光谱显示,该化合物的吸收截止边为743 nm,其禁带宽度Eg为4 eV.

Stimuli-responsive smart materials have garnered significant interest due to their potential applications in information storage and sensors.These materials possess a simple preparation process,versatile structure,and are cost-effective,particularly the organic-inorganic hybrid-type thermally responsive dielectric switching materials.To this end,we selected azetidine hydrochloride and cobalt chloride hexahydrate and utilized a straightforward solvent evaporation method to obtain blue transparent crystals,(C_(3)H_(6)NH_(2))_(2)CoCl_(4),a zero-dimensional organic-inorganic hybrid material exhibiting temperature responsiveness.It is notable that this compound undergoes a reversible structural phase transition at 347.7 K.And the enthalpy change of the material was consistent,as revealed by the differential scanning calorimetry(DSC)curves tested at different ramp-up and ramp-down rates.The heat absorption and exothermic peaks also displayed consistency at different rates,with the peaks demonstrating a tendency to contract.The crystal structure of the material underwent a phase transition from P21/n to Pnma space group,as evidenced by single crystal X-ray diffraction(SCXRD)data at variable temperatures.This transition was attributed to the deformation and displacement of the(CoCl_(4))^(2–)anions and the ordered-disordered movements of the(C_(3)H_(6)NH_(2))^(+)cation.The dielectric test results of(C_(3)H_(6)NH_(2))_(2)CoCl_(4) exhibited a step-like dielectric anomaly,with consistent dielectric changes over several dielectric cycles,demonstrating excellent dielectric switching properties.Weak interactions around the cations were calculated by Crystal Explorer,indicating that the main cause of the hybrid material formation was due to H⋅⋅⋅H interactions between the cations and H⋅⋅⋅Cl interactions between the anions and cations.Additionally,based on the ultraviolet-visible absorption spectroscopy,(C_(3)H_(6)NH_(2))_(2)CoCl_(4) displayed an absorption edge at 743 nm,with an estimated optical bandgap Eg of 4 eV.Moreover,the material demonstrated exceptional stability,cycle life,and durability,indicating its potential for a wide range of applications in energy storage,sensors,catalysts,and other fields.In conclusion,this work provides novel insights into the structural design and property modulation of organic-inorganic hybrid materials.