Studies on Magnetic and Dielectric Properties of Antiferromagnetically Coupled Dinuclear Cu(II) in a One-Dimensional Cu(II) Coordination Polymer

A one-dimensional Cu­(II) coordination polymer with encapsulated antiferromagnetically coupled binuclear Cu­(II) has been synthesized by using 5-nitroisophthalic acid (5-N-IPA) and 4-aminopyridine (4-APY) [Cu2(5-N-IPA)2(4-APY)4]n (1). Electrical properties are examined by complex impedance (Z*), dielectric permittivity (ε*), and ac conductivity studies at different frequencies (10 kHz–5 MHz) and temperatures (253–333 K). The contribution of grain and grain boundary has been explained by a different theoretical model. The variable temperature magnetic susceptibility data for compound 1 were recorded between 300 and 2 K. The shape of the curve (χMT vs T) indicates dominant antiferromagnetic coupling, which results from the interaction between the copper­(II) atoms.本研究以5-硝基间苯二甲酸（5-nitroisophthalic acid，5-N-IPA）与4-氨基吡啶（4-aminopyridine，4-APY）为配体，合成了一种封装有反铁磁耦合双核铜(II)单元的一维铜(II)配位聚合物，其分子式为[Cu₂(5-N-IPA)₂(4-APY)₄]ₙ（化合物1）。在10 kHz至5 MHz的不同频率以及253~333 K的温度区间内，通过复阻抗（complex impedance, Z*）、介电常数（dielectric permittivity, ε*）与交流电导率测试，对该配位聚合物的电学性能进行了表征。本研究借助不同理论模型阐释了晶粒与晶界对电学性能的贡献。针对化合物1，在300 K至2 K的温度范围内采集了变温磁化率数据；磁化率积χ_MT随温度T的变化曲线形态表明体系存在主导性的反铁磁耦合作用，该作用源于铜(II)原子间的相互作用。