Three new hetero-metallic Cu^II–Ln^III complexes [(CuL)Gd(NO₃)₃(CH₃OH)]_n (1), [(CuL)Tb(NO₃)₃(H₂O)]·[CuL] (2) and [(CuL)Dy(NO₃)₃(H₂O)]·[CuL] (3) have been synthesized using a mono-nuclear Cu(II) complex, [CuL], of an unsymmetrically di-condensed N₂O₃ donor Schiff base ligand, N-(3-methoxysalicylidene)-N-(salicylidene)-1,2-ethylenediamine (H₂L). Single crystal X-ray crystallography revealed that complex 1 is a nitrate bridged 1D chain of dinuclear Cu(II)–Gd(III) units whereas in 2 and 3, the dinuclear Cu(II)–Ln(III) units are co-crystallized with a [CuL] unit. The Ln(III) centers are nine coordinated with the geometry of a spherical capped square antiprism for Gd and spherical tricapped trigonal prism for Tb and Dy. The geometry of the Cu(II) center is distorted octahedral for complex 1 and distorted square planar for complexes 2 and 3. Temperature-dependent molar magnetic susceptibility measurements in 1–3 revealed the presence of overall ferromagnetic coupling between the Cu(II) and Ln(III) centers. Notably, field induced single-molecule magnet behavior was witnessed in the Tb(III) derivative (2). The ab initio calculations indicated that upon application of an external magnetic field, the tunneling in the ground state of complex 2 gets reduced and thereby field-induced SMM behaviour is observed. Besides, in the case of complex 1, BS-DFT calculations were carried out to gain further insights into the magnetic exchange coupling interactions between the Cu(II) and Gd(III) centers.

中文翻译：

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不对称 N2O3 供体配体的 Cu(II)–Ln(III)（Ln = Gd、Tb 和 Dy）配合物：Cu(II)–Tb(III) 配合物的场诱导 SMM 行为

三种新的异金属Cu ^II –Ln ^III配合物[(CuL)Gd(NO ₃ ) ₃ (CH ₃ OH)] _n ( 1 ),[(CuL)Tb(NO ₃ ) ₃ (H ₂ O)]·[ CuL] ( 2 ) 和 [(CuL)Dy(NO ₃ ) ₃ (H ₂ O)]·[CuL] ( 3 ) 使用单核 Cu( II ) 配合物 [CuL] 合成，其具有不对称结构双缩合N ₂ O ₃供体席夫碱配体，N- (3-甲氧基水杨基)-N- (水杨基)-1,2-乙二胺(H ₂ L)。单晶X射线晶体学显示配合物1是双核Cu( II )–Gd( III )单元的硝酸盐桥接一维链，而在2和3中，双核Cu( II )–Ln( III )单元是共结晶的带有[CuL]单位。 Ln( III ) 中心有九个，与 Gd 的球形封顶方形反棱镜和 Tb 和 Dy 的球形三封三棱柱的几何形状配位。配合物1的 Cu( II ) 中心的几何形状是扭曲的八面体，配合物2和3 的Cu(II) 中心的几何形状是扭曲的方形平面。1-3中与温度相关的摩尔磁化率测量揭示了 Cu( II ) 和 Ln( III ) 中心之间总体铁磁耦合的存在。值得注意的是，在 Tb( III ) 衍生物 ( 2 )中观察到了场感应单分子磁体行为。从头计算表明，在施加外部磁场时，配合物2基态的隧道效应会减少，从而观察到场诱导的 SMM 行为。此外，对于配合物1，进行了BS-DFT计算，以进一步了解Cu( II )和Gd( III )中心之间的磁交换耦合相互作用。