Two MnII coordination polymers with azide and the zwitterionic dicarboxylate ligand bis(N-carboxymethyl-4-pyridinium) (bcp) were synthesized, and structurally and magnetically characterized. They are formulated as [Mn3(bcp)2(N3)2(SO4)2(H2O)4]·6H2O (1) and [Mn4(bcp)2(N3)8(H2O)2]·4H2O (2). Compound 1 contains anionic linear [Mn3(N3)2(COO)4(SO4)2(H2O)4]4â units with simultaneous μ2-EO (end-on) azide, sulfate and carboxylate bridges, while compound 2 contains [Mn4(COO)4(N3)8(H2O)2]4â clusters with mixed μ2-EO azide, μ3-EO azide and carboxylate bridges. In these compounds, the anionic tri- or tetranuclear units are linked into coordination chains by the cationic bipyridinium spacers, and are also hydrogen bonded into chains by double OâHâ¯O bridges. Magnetic analyses were carried out on temperature-variable susceptibility data for both compounds, and also on isothermal magnetization data for 1. It is revealed that all the mixed double and triple bridges, [(EO-N3)(COO)(SO4)] in 1, [(COO)(EO-N3)2] and [(COO)(EO-N3)] in 2, transmit antiferromagnetic coupling between MnII ions. The [(EO-N3)2] bridge in 2, with MnâNâMn = 96.6°, also transmits antiferromagnetic coupling, providing the first example in the antiferromagnetic regime predicted theoretically for double EO-azide bridges between MnII ions. The double hydrogen bonding [(OâHâ¯O)2] bridges in both compounds induce weak antiferromagnetic interactions.
研究人员合成了两种含有
叠氮化物和双(N-羧甲基-4-
吡啶鎓)(bcp)二
羧酸盐
配体的 MnII 配位聚合物,并对其结构和磁性进行了表征。它们的配方分别为[Mn3(bcp)2(N3)2(SO4)2(
H2O)4]Â-6 (1)和[Mn4(bcp)2(N3)8( )2]Â-4 (2)。化合物 1 含有阴离子线性[Mn3(N3)2(COO)4(SO4)2( )4]4â单元,同时具有δ2-
EO(端对端)
叠氮桥、
硫酸桥和
羧酸桥;化合物 2 含有[Mn4(COO)4(N3)8( )2]4â团簇,具有混合的δ2-
EO 叠氮桥、δ3-
EO 叠氮桥和
羧酸桥。在这些化合物中,阴离子三核或四核单元通过阳离子双
吡啶鎓间隔物连接成配位链,并通过双 OâHâ¯O 桥氢键连接成链。对这两种化合物的温变磁感应强度数据和 1 的等温磁化数据进行了磁性分析。结果表明,所有混合双桥和三桥,即 1 中的 [(
EO-N3)(COO)(SO4)] 、2 中的 [(COO)(
EO-N3)2] 和 [(COO)(
EO-N3)] 都在 MnII 离子之间传递反
铁磁耦合。2 中的[(
EO-N3)2]桥(MnâNâMn = 96.6°)也传递反
铁磁耦合,这是在理论上预测的 MnII 离子间双
EO 叠氮桥的反
铁磁机制中的第一个实例。这两种化合物中的双氢键[(OâHâ¯O)2]桥引起了微弱的反
铁磁相互作用。