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A series of cobaltIJII) coordination polymers {; ; [CoIJL1)2(H2O)2]·4H2O·2DMF}; ; n (1 ; HL1 = 4-(3, 5- (dicyano-2, 6- dipyridyl)dihydropyridyl)benzoic acid ; DMF = N, N-dimethylformamide), {; ; [Co(L1a)2(H2O)2]·2H2O}; ; n (2, HL1a = 4-(3, 5-dicyano-terpyridyl)benzoic acid), and [Co3(μ3-OH)2(L1a)2(TP)(H2O)2]n (3, TPA = terephthalic acid) are reported, in which the conformation of the primary ligand L1 − has been regulated by in situ oxidative dehydrogenation into L1a− in different solvent systems. Single crystal structural analyses reveal that compound 1 exhibits a 44 -sql coordination layer structure constructed from cobalt centres and parent L1 − ligands ; compound 2 is constructed from Co2+ cations doubly connected by L1a− anions, which are generated in situ through oxidative dehydrogenation of L1 − ; while compound 3 features a rod-packing 3D network with a pcu-type topology, in which cobalt–oxygen chain units are interconnected by L1a− and TP2− mixed ligands. The formation mechanism of L1a− ligand via an in situ oxidative dehydrogenation reaction has been briefly discussed. This current study confirms that in situ ligand transformation is viable for controlled coordination polymer assembly, and is also adaptable to a more complexed ligand system.

2-Fold interpenetrating chiral quartz nets with opposite handedness have been observed in a centrosymmetric coordination polymer {[Zn3(bmzbc)6]·11.5DMF}n (Hbmzbc = 4-(benzimidazole-1-yl)benzoic acid), which is a unique example of an interpenetrating enantiomorphic pair of quartz nets that have never been realized before.

Two mononuclear compounds Ln(e-urea)8(NO3)3 (Ln = Dy(1) and Tb(2)) have been urothermally synthesized by using the ethyleneurea (e-urea) as an organic ligand and a solvent. The e-urea ligand with a single donor atom is a unique ligand for coordinating to lanthanide ions, which is very different from those commonly observed polytopic ligands with suitable coordination pockets to encapsulate lanthanide(III) ions or chelating organic ligands. The lanthanide center surrounded by eight e-urea ligands is in a square antiprismatic environment with an approximate D4d local symmetry. Magnetic properties of both compounds have been investigated in detail using direct-current and alternating-current susceptibility measurements. The Dy(1) analogue displays slow magnetic relaxation behavior with an effective energy barrier of the magnetic relaxation of 37.68 K and the pre-exponential factor τ0 of 1.47 × 10−9 s in the presence of direct-current field of 2 kOe.

Two metal–organic frameworks {[Zn2(DSBDC)(dpp)2](H2O)2}n (1) (H4DSBDC = 2,5-disulfonylterephthalate acid and dpp = 1,3-di(4-pyridyl)propane) and [Cd2(SBTC)(dpp)1.5]n (2) (H4SBTC = 5-sulfonyl-1,2,4-benzenetricarboxylic acid) with novel sulfonate–carboxylate ligands have been synthesized and structurally characterized. The in situ formation of the H4DSBDC ligand derived from H4SBTC is unprecedented and involves a fundamentally new substitution of sulfonate for carboxylate in the in situ ligand synthesis reaction. The solid state structures of 1 and 2 consist of neutral 2D metal aromatic sulfonate–carboxylate layers, which are pillared by the dpp ligands to generate different 3D architectures. The topological structure of 1 is a trinodal net based on three kinds of topologically equivalent 4-connected nodes with the Schlafli symbol of (64.82). The framework of 2 can be classified as a 4,5,6-connected 3D net with the Schlafli symbol of (43.63) (43.65.82) (46.66.83). In the solid state, compounds 1 and 2 exhibit white-ish and blue photoluminescences, respectively.

Hydrothermal reactions of Zn(NO3)2 or Pb(NO3)2 with 1,4-naphthalenedicarboxylic acid (1,4-H2ndc) and 1,3-di(4-pyridyl)propane (dpp) lead to two novel metal oxo cluster-based coordination polymers, namely, [Zn5(μ3-OH)2(1,4-ndc)4(dpp)2]n (1) and [Pb5(μ4-O)(1,4-ndc)4(dpp)]n (2). The structures exhibit different cluster motifs depending on the nature of the metal ions. Compound 1 features a 3D structure based on the pentanuclear [Zn5(μ3-OH)2] secondary building unit (SBU) where the five zinc atoms are coplanar; its topological structure is an uninodal 10-connected network of (36.434.53.62) topology. The zinc ions in 1 have a coordination number varying from 4 to 6 and are accompanied by a variety of coordination geometries such as tetrahedral, trigonal bipyramidal, and octahedral. Compound 2 has a 3D architecture containing an unusual hexanuclear [Pb6(μ4-O)2] cluster unit composed of two edge-sharing oxygen-centred [Pb4(μ4-O)] tetrahedrons. One explanation for the presence of the centred bridging oxide ligands in 2 is that owing to steric constraints sufficient carboxylate ligands cannot coordinate to the Pb(II) centers to satisfy the positive charges of the Pb(II) cations. The Pb(II) ions in 2 exhibit diverse hemidirected coordination geometries with coordination numbers of 6 and 7. In the solid state, compounds 1 and 2 exhibit photoluminescence with emission maximum at 495 and 420 nm, respectively.

Hydro(solvo)thermal reactions of cadmium(II) salts with 4-methyl-1,2,4-triazole-3-thiol (Hmptrz) afforded six novel cadmium(II) coordination polymers, namely, [Cd(mptrz)2]n (1), [Cd(mptrz)X]n (X = Br (2) and I (3)), [Cd(mptrz)(μ2-X)]n (X = Br (4) and Cl (5)), and [Cd3(μ3-OH)2(mptrz)4]n (6). Compound 1 is a 1D looped chain structure. Compounds 2 and 3 are isostructural and have 1D ladder structures. Compounds 4 and 5 are isomorphs and feature 2D layered structures. Cadmium(II) bromide formed 1D ladder of 2 and 2D layer of 4, representing an unusual example of Br bond isomerism. Compound 6 has a 1D tape structure with an uncommon 1D inorganic ⋯Cd2(μ3-OH)2–Cd–Cd2(μ3-OH)2⋯ chain. The structural diversity of these materials is reflected in the variety of coordination polyhedra displayed by the cadmium sites: tetrahedral; trigonal bipyramidal; octahedral. The solid state photoluminescence of all compounds have been investigated. However, only compound 6 exhibits photoluminescence with an emission maximum at 435 nm upon excitation at 346 nm. Solid-state density functional theory (DFT) calculations were performed on compound 6. In addition, these compounds were characterized by IR, elemental analysis, and thermogravimetric analysis.

Solvothermal reactions of zinc acetate, sodium hydroxide, and sulfosuccinic acid (H3SSC) in alcohol/H2O, afforded two new three-dimensional (3D) heterometallic sulfonate-carboxylate frameworks, namely, [Na2Zn3(μ3-OH)2(SSC)2(H2O)4]n (1) and [Na4Zn(SSC)2(H2O)3.5]n (2). Compound 1 contains 2D anionic [Zn3(μ3-OH)2(SSC)2]2− layers based on the centrosymmetric mononuclear [Zn(SSC)2]4− units, while compound 2 has 2D anionic [NaZn(SSC)2]3− layers based on the [Zn2(SSC)2] macrocycle units. In both compounds, the 2D anionic layers are linked by sodium ions in various manners to generate quite different 3D architectures. Compounds 1 and 2 exhibit violet photoluminescences in the solid state. In addition, IR spectra, powder X-ray diffraction, elemental analysis, and thermogravimetric analysis of compounds 1 and 2 are also investigated.

The reactions of Ln(NO3)3 with 2,5-dihydroxy-1,4-benzenedicarboxylic acid (H2-DHBDC) under solvothermal conditions produce a series of isomorphous lanthanide coordination polymers with the empirical formula {[Ln2(DHBDC)3(DMF)4](DMF)2}n (Ln = La(1), Nd(2), Sm(3), Gd(4), and Er(5)). Compound {[Ln2(DHBDC)3(DMF)4](DMF)2}n contains dinuclear Ln2(COO)6 units, which are linked by the –C6H2(OH)2– spacers to form a three-dimensional framework exhibiting α-Po topology (pcu-(412·63) net) based on dinuclear Ln2(COO)6 nodes. The three-dimensional framework shows one-dimensional open channels that accommodate the coordinated and guest DMF molecules. Gas adsorption measurements on compound 4 indicate that the desolvated solid of 4 adsorbs CO2 and shows nonporous behavior toward N2. The adsorption favoring CO2 over N2 may arise from the chemical environments of the host framework, which contains the polar –OH groups of the phenyl and the π-electrons of the ligands. Magnetic measurements on compound 4 indicate that there is an antiferromagnetic interaction between Gd3+ ions.

Self-assembly of Ag(NO3)2 with 5-sulfoisophthalic acid monosodium salt (NaH2SIP) in the presence of piperazine (pip) or 4,4′-bipyridyl (bpy) produced two new silver(I) coordination polymers, {(H2pip)2[Ag8(SIP)4(H2O)4](H2O)4}n (1) and {[Ag(bpy)][Ag(HSIP)(bpy)](H2O)2}n (2), respectively. Single-crystal X-ray diffraction reveals that compound 1 has a 2D silver carboxylate-sulfonate layered structure containing an uncommon octanuclear [Ag8(CO2)8] cluster wherein the eight silver(I) atoms form two intersecting Ag4 planes. The 2D layers are further linked by the H2pip molecules through hydrogen bonds into a 3D supramolecular structure. Compound 2 features a 2D supramolecular network formed by silver(I)-bpy double chains and HSIP ligands through the combination of coordination bonds, ligand unsupported Ag⋯Ag interactions and weak Ag⋯O coordinative interactions. In the solid state at room temperature, compound 1 exhibits blue photoluminescence with a maximum at 450 nm upon excitation at 365 nm. Compound 2 shows green photoluminescence with a maximum at 564 nm upon excitation at 392 nm.