A thermally stable three-dimensional cobalt(II) coordination polymer based on the V-shaped ligand 4-(4-carboxyphenoxy)isophthalate

Syntheses, structures and magnetic properties of two CoII/NiII isostructural coordination polymers based on an asymmetric semirigid tricarboxylate ligand

Two new isostructural complexes, namely, poly[aqua[μ₃-2-(4-carboxyphenoxy)terephthalato-κ³O¹:O⁴:O^4'](1,10-phenanthroline-κ²N,N')cobalt(II)], [Co(C₁₅H₈O₇)(C₁₂H₈N₂)(H₂O)]_n or [Co(μ₃-Hcpota)(phen)(H₂O)]_n, I, and poly[aqua[μ₃-2-(4-carboxyphenoxy)terephthalato-κ³O¹:O⁴:O^4'](1,10-phenanthroline-κ²N,N')nickel(II)], [Ni(C₁₅H₈O₇)(C₁₂H₈N₂)(H₂O)]_n or [Ni(μ₃-Hcpota)(phen)(H₂O)]_n, II, have been synthesized by solvothermal reactions. Complexes I and II were fully characterized by IR spectroscopy, elemental analyses, thermogravimetric analyses, and powder and single-crystal X-ray diffraction. They both present two-dimensional structures based on [M₂(μ-COO)₂]²⁺ (M = Co^II or Ni^II) dinuclear metal units with a fes topology and a vertex symbol (4·8²). Interestingly, the positions of the two dimeric metal motifs and the two partially deprotonated Hcpota^2- ligands reproduce regular flying butterfly arrangements flipped upside down and sharing wings in the ab plane. Magnetic studies indicate antiferromagnetic interactions (J = -5.21 cm^-1 for I and -11.53 cm^-1 for II) in the dimeric units, with Co...Co and Ni...Ni distances of 4.397 (1) and 4.358 (1) Å, respectively, that are related to double syn-anti carboxylate bridges.

A novel three-dimensional tetranuclear CoII coordination polymer with water hexamers based on the V-shaped tetracarboxylate ligand 4-(2,4-dicarboxylatophenoxy)phthalate

A new coordination polymer (CP), namely, poly[[diaquatris[μ₂-1,4-bis(1H-imidazol-1-yl)benzene]bis[μ₆-4-(2,4-dicarboxylatophenoxy)phthalato]tetracobalt(II)] hexahydrate], {[Co₄(C₁₆H₆O₉)₂(C₁₂H₁₀N₄)₃(H₂O)₂]·6H₂O}_n, has been synthesized by solvothermal reaction. The CP was fully characterized by IR spectroscopy, elemental analysis, thermogravimetric analysis, and powder and single-crystal X-ray diffraction. It presents a three-dimensional (3D) structure based on tetranuclear Co^II secondary building units (SBUs) with a tfz-d net and point symbol (4³)₂(4⁶·6¹⁸·8⁴). The 4-(2,4-dicarboxyphenoxy)phthalic acid (H₄dcppa) ligands are completely deprotonated and link {Co₄(COO)₄}^4- SBUs into two-dimensional (2D) layers. Furthermore, adjacent layers are connected by 1,4-bis(1H-imidazol-1-yl)benzene (bib) ligands, giving rise to a 3D supramolecular architecture. Interestingly, there are numerous elliptical cavities in the CP where isolated unique discrete hexameric water clusters have been observed. The results of thermogravimetric and magnetic analyses are described in detail.

A new family of lanthanide coordination polymers based on 3,3'-[(5-carboxylato-1,3-phenylene)bis(oxy)]dibenzoate: synthesis, crystal structures and magnetic and luminescence properties

Six two-dimensional (2D) coordination polymers (CPs), namely, poly[{μ₅-3,3-[(5-carboxylato-1,3-phenylene)bis(oxy)]dibenzoato-κ⁶O¹:O^1':O³,O^3':O⁵:O^5'}bis(N,N-dimethylformamide-κO)lanthanide(III)], [Ln(C₂₁H₁₁O₈)(C₃H₇NO)₂]_n, with lanthanide/Ln = cerium/Ce for CP1, praseodymium/Pr for CP2, neodymium/Nd for CP3, samarium/Sm for CP4, europium/Eu for CP5 and gadolinium/Gd for CP6, have been prepared by solvothermal methods using the ligand 3,3'-[(5-carboxy-1,3-phenylene)bis(oxy)]dibenzoic acid (H₃cpboda) in the presence of Ln(NO₃)₃. The complexes were characterized by single-crystal X-ray and powder diffraction, IR spectroscopy, elemental analysis and thermogravimetric analysis (TGA). All the structures of this family of lanthanide CPs are isomorphous with the triclinic space group P-1 and reveal that they have the same 2D network based on binuclear Ln^III units, which are further extended via interlayer C-H...π interactions into a three-dimensional supramolecular structure. The carboxylate groups of the cpboda^3- ligands link adjacent Ln^III ions and form binuclear [Ln₂(RCOO)₄] secondary building units (SBUs), in which each binuclear Ln^III SBU contains four carboxylate groups from different cpboda^3- ligands. Moreover, with the increase of the rare-earth Ln atomic radius, the dihedral angles between the aromatic rings gradually increase. Magnetically, CP6 shows weak antiferromagnetic coupling between the Gd^III ions. The solid-state luminescence properties of CP2, CP5 and CP6 were examined at ambient temperature and CP5 exhibits characteristic red emission bands derived from the Eu³⁺ ion (CIE 0.53, 0.31), with luminescence quantum yields of 22%. Therefore, CP5 should be regarded as a potential optical material.

Structural diversity, magnetic properties and luminescence of NiII, CoII and ZnII coordination polymers derived from 3,3'-[(5-carboxy-1,3-phenylene)bis(oxy)]dibenzoic acid and 1,10-phenanthroline

Three novel coordination polymers (CPs), namely poly[[di-μ-aqua-bis{μ₄-3,3'-[(5-carboxylato-1,3-phenylene)bis(oxy)]dibenzoato-κ⁵O¹:O^1',O³:O⁵:O^5'}bis(1,10-phenanthroline-κ²N,N')trinickel(II)] dimethylformamide 1.5-solvate trihydrate], {[Ni₃(C₂₁H₁₁O₈)₂(C₁₂H₈N₂)₂(H₂O)₂]·1.5C₃H₇NO·3H₂O}_n, (I), poly[[di-μ-aqua-bis{μ₄-3,3'-[(5-carboxylato-1,3-phenylene)bis(oxy)]dibenzoato-κ⁵O¹:O^1',O³:O⁵:O^5'}bis(1,10-phenanthroline-κ²N,N')tricobalt(II)] diethylamine disolvate tetrahydrate], {[Co₃(C₂₁H₁₁O₈)₂(C₁₂H₈N₂)₂(H₂O)₂]·2C₂H₇N·4H₂O}_n, (II), and catena-poly[[aqua(1,10-phenanthroline-κ²N,N')zinc(II)]-μ-5-(3-carboxyphenoxy)-3,3'-oxydibenzoato-κ²O¹:O³], [Zn(C₂₁H₁₂O₈)(C₁₂H₈N₂)(H₂O)]_n, (III), have been synthesized by the reaction of different metal ions (Ni²⁺, Co²⁺ and Zn²⁺), 3,3'-[(5-carboxy-1,3-phenylbis(oxy)]dibenzoic acid (H₃cpboda) and 1,10-phenanthroline (phen) under solvothermal conditions. All the CPs were characterized by elemental analysis, single-crystal and powder X-ray diffraction, FT-IR spectroscopy and thermogravimetric analysis. Complexes (I) and (II) have isomorphous structures, featuring similar linear trinuclear structural units, in which the central Ni^II/Co^II atom is located on an inversion centre with a slightly distorted octahedral [NiO₆]/[CoO₆] geometry. This comprises four carboxylate O-atom donors from two cpboda^3- ligands and two O-atom donors from bridging water molecules. The terminal Ni^II/Co^II groups are each connected to the central Ni^II/Co^II cation through two μ_1,3-carboxylate groups from two cpboda^3- ligands and one water bridge, giving rise to linear trinuclear [M₃(μ₂-H₂O)₂(RCOO)₄] (M = Ni²⁺/Co²⁺) secondary building units (SBUs) and the SBUs develop two-dimensional-networks parallel to the (100) plane via cpboda^3- ligands with new (3²·4)₂(3²·8³·9)₂(3⁴·4².8²·9⁴·10³) topological structures. Zinc complex (III) displays one-dimensional coordination chains and the five-coordinated Zn atom forms a distorted square-pyramidal [ZnO₃N₂] geometry, which is completed by two carboxylate O-atom donors from two distinct Hcpboda^2- ligands, one O atom from H₂O and two N atoms from a chelating phen ligand. Magnetically, CP (I) shows weak ferromagnetic interactions involving the carboxylate groups, and bridging water molecules between the nickel(II) ions, and CP (II) shows antiferromagnetic interactions between the Co²⁺ ions. The solid-state luminescence properties of CP (III) were examined at ambient temperature and the luminescence sensing of Cr₂O₇^2-/CrO₄^2- anions in aqueous solution for (III) has also been investigated.