Diverse manganese(ii) coordination polymers derived from achiral/chiral imidazolium-carboxylate zwitterions and azide: structure and magnetic properties
作者:Xuan Wang、Xiu-Bing Li、Ren-He Yan、Yan-Qin Wang、En-Qing Gao
DOI:10.1039/c3dt50510c
日期:——
Five Mn(II) coordination polymers containing azide and carboxylate as simultaneous bridges have been derived from different imidazolium-carboxylate zwitterionic ligands: 1-methyl-3-(carboxylatomethyl)imidazolium (L1), 1,3-bis(carboxylatomethyl)imidazolium (L2), (S,S)-, (R,R)-, and (R,S)-1,3-bis(1-carboxylatoethyl)imidazolium (S,S-L3, R,R-L3 and R,S-L3). The compounds are formulated as [Mn(L1)(N3)2] (1), [Mn(L2)(N3)] (2), [Mn(R,R-L3)(N3)]·0.5CH3OH (3-R), [Mn(S,S-L3)(N3)]·0.5CH3OH (3-S), [Mn(R,S-L3)(N3)] (4). In compound 1, the neutral monocarboxylate zwitterion ligand (L1) leads to uniform chains with bis(azide)(carboxylate) bridges. For compounds 2–4, the anionic dicarboxylate zwitterions L2 and L3 lead to (azide)bis(carboxylate) bridges, but the overall coordination networks are different. In 2 and 3-S (or 3-R), chains with the (azide)bis(carboxylate) bridges are connected by L2 and S,S-L3 (or R,R-L3), respectively, to give achiral and chiral 2D coordination networks with different connecting topologies. In compounds 4, which is derived from the mesomeric ligand R,S-L3, linear trinuclear units with the (azide)bis(carboxylate) bridges are linked by μ-1,3 azides to give 2D layers, and the layers are pillared into a 3D framework by the 1,3-dimethyleneimidazolium tethers. Magnetic analyses suggested that compounds 1–3 behave as 1D antiferromagnetic systems, while 4 shows canted antiferromagnetism with weak ferromagnetic ordering below TC = 12.4 K.
由不同的
咪唑鎓-
羧酸盐齐聚物衍生出了五种同时含有
叠氮化物和
羧酸盐作为桥的
锰(II)配位
聚合物:
1-甲基-3-(羧基
甲基)
咪唑鎓(L1)、
1,3-双(羧基
甲基)
咪唑鎓(
L2)、(S,S)-、(R,R)- 和 (R,S)-
1,3-双(1-羧基乙基)
咪唑鎓(S,S-L3、R,R-L3 和 R,S-L3)。这些化合物的配方为[Mn(L1)(N3)2](1)、[Mn(
L2)(N3)](2)、[Mn(R,R-L3)(N3)]-0.5CH3OH(3-R)、[Mn(S,S-L3)(N3)]-0.5CH3OH(3-S)、[Mn(R,S-L3)(N3)](4)。在化合物 1 中,中性单
羧酸盐齐聚物
配体(L1)形成了具有双(
叠氮)(
羧酸盐)桥的均匀链。对于化合物 2-4,阴离子二
羧酸盐齐聚物
L2 和 L3 会产生(
叠氮)双(
羧酸)桥,但整体配位网络不同。在 2 和 3-S(或 3-R)中,带有(
叠氮)双(
羧酸)桥的链分别由
L2 和 S,S-L3(或 R,R-L3)连接,从而得到具有不同连接拓扑结构的非手性和手性二维配位网络。在由中间
配体 R,S-L3 衍生出的化合物 4 中,具有(
叠氮)双(
羧酸)桥的线性三核单元通过 μ-1,3
叠氮化物连接,形成二维层,这些层通过 1,3-二亚
甲基咪唑鎓拴成三维框架。磁性分析表明,1-3 号化合物表现为一维反
铁磁系统,而 4 号化合物在 TC = 12.4 K 以下表现为具有弱
铁磁有序性的悬臂反
铁磁。