Triazolate-based 3D frameworks and a 2D layer with centrosymmetric Cu^II₇, Cu^II₅, Cu^II₄ clusters and tunable interlayer/interchain compactness: hydrothermal syntheses, crystal structures and magnetic properties

Abstract

Four 1,2,3-triazolate-based coordination polymers (CPs) with varied dimensionality, different nuclearity numbers and core topologies, [Cu4(μ-OH)(μ3-OH)(ta)2(btec)]n (1), {[Cu6(μ3-OH)2(ta)8(tp)]·2.5H2O}n (2), {[Cu5(μ3-OH)2(ta)4(ip)2]·2H2O}n (3) and {[Cu5(μ-OH)2(μ3-OH)2(ta)2(pa)2]·2H2O}n (4) (ta = 1,2,3-triazolate, btec = 1,2,4,5-benzenetetracarboxylate, tp = terephthalate, ip = isophthalate and pa = phthalate), were hydrothermally synthesized by varying the numbers and positions of the carboxylate group appended on the phenyl tether, and structurally and magnetically characterized. The former three entities are three-dimensional (3D) robust frameworks with a (4(4)·6(2))(4(11)·6(5))2(4(13)·6(10)·8(5)) topological net containing centrosymmetric Cu(II)7 clusters, square-planar Cu(II)1 cores and tetratopic btec(4-) linkers for 1, a pillared-layered structure consisting of Cu(II)5 + Cu(II)1-based coplanar layers and ditopic tp(2-) pillars for 2 as well as a microporous architecture derived from Cu(II)5 clusters and directional ip(2-) connectors for 3. In contrast, complex exhibits an undulated two-dimensional (2D) layer with alternating Cu(II)4 + Cu(II)1 chains interconnected by anionic pa(2-) connectors. Crystallographically, the increment of the local nuclearity from Cu(II)4 up to Cu(II)7 in 1-4 benefits greatly from the synergistic co-coordination of the hydroxyl group and the coplanar ta(-) ligand towards the metal ion, and the interlayer/interchain compactness is significantly tuned by the position isomerism of the dicarboxylate moieties. Due to the antiferromagnetic coupling in the local clusters and the asymmetric superexchange by μ3-ta(-) mediator, these complexes 4 exhibit different spin ground states (paramagnetic S = 1 and 1/2, ferrimagnetic S = 1/2 as well as spin canting) at low temperatures, which are informative for polynuclear-based magnetic materials.

Copper(II) Coordination Polymers Self-Assembled from Aminoalcohols and Pyromellitic Acid: Highly Active Precatalysts for the Mild Water-Promoted Oxidation of Alkanes

“…The structural difference between 1 and 2 mainly concerns the absence in 2 of H 2 O ligands and the presence of only one η 1 :η 0 –COO mode of carboxylate groups in μ 4 -pma. The bonding parameters in 1 and 2 are comparable to those of other copper­(II) compounds bearing dmea, , Hedea, , or pyromellitate , moieties. Besides, compound 2 represents the first coordination polymer derived from N -ethyldiethanolamine …”

“…The selection of pyromellitic acid was governed by its recognized application as a linker in crystal engineering of copper­(II)-organic networks. , Despite similar network dimensionality, compounds 1 – 3 are built from the structurally distinct dicopper­(II) or monocopper­(II) aminoalcoholate secondary building units (SBUs). Their self-assembly appeared to be primarily guided by the type of aminoalcohol building block, which also influences the solubility of the resulting product in H 2 O.…”

Crystal structure of catena-poly[octaaqua-bis(μ2-4,6-dicarboxyisophthalate-κ2 O:O′)cadmium(II)disodium(I)] dihydrate, C20H28CdNa2O26

“…Crystal engineering provides a powerful tool for the design and synthesis of novel compounds, and the advances in theory and practice of molecular crystallography have increased the speed and scope of structure determination enormously. Organic aromatic polycarboxylate ligands, as one kind of multi-dentate O-donor ligands have been extensively employed in the preparation of coordination polymer in possession of multi-dimensional networks and interesting properties [5,6]. Taking these advantages into account, recently we have begun to assemble H4btec, sodium ions and cadmium ions into polymeric complexes under hydrothermal conditions.…”

Synthesis, X-ray structures, and magnetic properties of seven polynuclear Cu(ii) complexes containing pyrazole-3,5-dicarboxylate with various ancillary ligands

“…13 Polynuclear Cu( ii ) complexes display diverse magnetic behaviors, such as ferromagnetic (F), antiferromagnetic (AF), spin canted antiferromagnetic interactions, and metamagnetism. 14–18 Copper( ii ) center contains one unpaired electron ( S = 1/2) and exhibits versatile coordination numbers and geometries owing to the Jahn–Teller distortion. 19,20 The short magnetic bridging ligands such as carboxylate, pyrazole, azide, and cyanide are excellent candidates for constructing magnetic materials.…”