Structures and magnetic properties of copper(ii) and manganese(ii) polymers derived from pseudohalides and a flexible zwitterionic dicarboxylate ligand

Abstract

The flexible zwitterionic dicarboxylate ligand 1,4-bis(4-carboxylato-1-pyridinium)butane (bcpb) assumes different conformations to collaborate with pseudohalides in various coordination modes to produce coordination polymers in which distinct anionic motifs with mixed carboxylate and pseudohalide bridges are interlinked by the cationic butylenebis(pyridinium) tethers. The Cu(II) compound, [Cu2(bcpb)(N3)4]n·nH2O (1), is a 1D coordination polymer based on the defective dicubane-like [Cu4(μ3-1,1,1-N3)2(μ-1,1-N3)2(μ-1,1-OCO)2] cluster. With Mn(II), four distinct 3D coordination polymers, [Mn4(bcpb)4(N3)(H2O)4]n(ClO4)7n·nCH3OH·3nH2O (2), [Mn2.5(bcpb)(N3)5(H2O)2]n (3), [Mn2(bcpb)(N3)4]n·nH2O (4), and [Mn2(bcpb)(NCO)4]n·nH2O (5), were characterized. 2 is the first Mn(II) compound with the rare μ4-1,1,3,3 azide bridge and exhibits an unusual 3D framework based on the [Mn4(μ4-1,1,3,3-N3)(μ-1,3-OCO)6] cluster. In 3, the unique undulated honeycomb-like [Mn2(μ-1,3-N3)3]n layers are interlinked into a 3D framework by disordered [Mn(μ-1,1-N3)4(μ-1,3-OCO)2] and [(O(aqua)-H)2···OCO]2 moieties, and the bcpb ligands serve as additional interlayer linkers to lead to the rare self-catenated 6(6) net. 4 and 5 show 3-fold interpenetrated 3D frameworks based on the chains with (μ-1,1-N3)2(μ-1,3-OCO) and (μ-N,N-NCO)2(μ-1,3-OCO) bridges, respectively. Magnetic studies indicated that 1 shows competing ferromagnetic and antiferromagnetic interactions. Compounds 2-5 all show antiferromagnetic coupling between Mn(ii) ions, while 3 shows 3D ordering. Analyses of magneto-structural data suggest a general trend that the antiferromagnetic interaction through (μ-1,1-N3)2(μ-1,3-OCO) or (μ-N,N-NCO)2(μ-1,3-OCO) increases with a decrease of the Mn···Mn distance.

Synthesis, Crystal Structure, Luminescence and Magnetism of Three Novel Coordination Polymers Based on Flexible Multicarboxylate Zwitterionic Ligand

“…According to the aforementioned considerations, we chose H 3 CbdcpCl as our organic ligand to react with different d-block metal salts under similar hydrothermal conditions, in order to explore the influence of multicarboxylate groups, the flexible linker and metal ions in the final frameworks. Applying this strategy, here we successfully get three new complexes, namely, {[Zn(HCbdcp) 2 (3). Their syntheses, crystal structures, luminescence and magnetic properties were reported in this paper.…”

“…Their syntheses, crystal structures, luminescence and magnetic properties were reported in this paper. Results proved that the Cbdcp ligand is a good candidate to construct novel CPs, for its various coordination modes and its rotationally flexible CH 2 linker. In addition, the luminescence properties of 1 and the magnetic properties of 2 and 3 indicate that compound 1 may be used as luminescent materials, and 2 and 3 have potential to be used in magnetic materials.…”

“…The asymmetric unit of 2 contains one crystallographically independent Mn(II) ion and one Cbdcp 2− ligand. Each Mn(II) ion is six-coordinated with oxygen atoms from six fully deprotonated Cbdcp 2− ligands, to conform to a distorted octahedral coordination geometry with the Mn-O bond lengths varying from 2.145 (2) …”

“…Flexible multicarboxylate zwitterionic ligands are one of the intensely studied topics in designing and constructing coordination polymers (CPs) [1][2][3][4], for they not only take advantage of carboxylate compounds, but also develop their potentials as flexible ligands. Under hydrothermal conditions or when deprotonated, multicarboxylate groups in flexible multicarboxylate zwitterionic ligands are efficient to create diverse frameworks owing to their mutable linking or coordination modes [5][6][7][8].…”

Synthesis, Structures, and Photoluminescence Properties of Five Novel Zinc(II) and Cadmium(II) Coordination Polymers based on Different Zwitterionic Pyridine Ligands

“…Zwitterionic pyridine ligands are one of the intensely studied topics in rational designing and constructing coordination polymers (CPs) and they are of great interest owing to their intriguing frameworks and potential application as functional materials in magnetism, optical properties, drug delivery, gas storage, and chemical separation . In the formation of CPs, molecular self‐assembly of metal ions and organic ligands, especially polycarboxylate ligands based on the principle of crystal engineering has proved to be an efficient approach .…”