Two new one-dimensional chain complexes, ( NH4 ) 2 [ Cu ( NH3) 2 ( CrO4 ) 2 ] (1) and ( NH4 ) 2·[ Ni(NH3)2(Cr04)2] (2) , were obtained by mixing copper nitrate or nickel nitrate with the same molar of ammonium dichromate in ammonia water at room temperature, and they were characterized by single-crystal X-ray diffraction (XRD) , thermogravimetric analysis ( TGA) and differential thermal analysis ( DTA ). Furthermore , the complexes were magnetically characterized by temperature-dependent magnetic susceptibility, field-dependent magnetization, and alternate current (AC) magnetic measurements. The structure analysis resultsrnshow that crystals of both complexes are triclinic, space group P(1) with a = 0. 59090(12) nm, 6 = 0. 6929(3) nm, c = 0. 73740(15) nm, α = 107. 03 (4)°, β = 92. 79(3)°, γ=112.44(2)° for Cu(Ⅱ) complex and 0 = 0.56987(7) nm, b = 0. 69972(9) nm, c = 0. 73335(8) nm, α = 104. 929 (3 )°, β = 96.7121(3)°, γ=112. 325(4)° for Ni( Ⅱ ) complex. In the crystal structure, the [ M( NH3)2]2+ units are linked by two chromato bridges, forming an eight-member ring. As a whole, both complexes have one-dimensional chain structures. The two complexes began to break down as the temperature gradually reached 150℃ or so, leaving behind H2Cr2Cu05 and H2Cr2Ni05, and afterwards they are dehydrated at above 410℃. The temperature-dependent magnetic susceptibilities were measured in the range of 2-300 K, which implies a weak antiferro-magnetic interaction between the adjacent mental ions. The field-dependent magnetization and AC magnetic measurements indicate that the two complexes are both antiferromagnets.%设计合成了2个一维链状铬酸根桥连的配位聚合物(NH4)2[Cu(NH3)2(CrO4)2](1)和(NH4)2·[Ni(NH3)2(CrO4)2](2),并对其进行了X射线单晶结构分析、热重-差热分析和多种磁学测试.晶体结构分析表明,2个配合物的晶体均属于三斜晶系,空间群均为P1.配合物1的晶胞参数为:a=0.59090(12)nm,b=0.6929(3) nm,c=0.73740(15) nm,α=107.03(4)°,β=92.79(3)°,γ=112.44(2)°；配合物2的晶胞参数为:a=0.56987(7)nm,b=0.69972(9) nm,c=0.73335(8)nm,α=104.929(3)°,β=96.121(3)°,γ=112.325(4)°.热重分析结果表明,配合物1和2均在150 ℃左右开始分解,生成H2Cr2CuO5和H2Cr2NiO5,在410℃以上继续分解,脱水得到相应的氧化物.配合物的变温磁化率测试结果表明,相邻Cu(Ⅱ)离子(配合物1)或Ni(Ⅱ)离子(配合物2)之间存在较弱的反铁磁相互作用；低温变场和交流磁化率测试结果表明,2个配合物均为反铁磁体.
展开▼
