Three Cu(II) complexes of [Cu(L1)(Br)2]·CH3CN (1), [Cu(L2)2(OAc)](PF6)·2C2H5OH (2), and [Cu(L1)(L2)](PF6)2 (3) (L1 = 2-(6-(pyridine-2-yl)-4-p-tolylpyridin-2-yl)pyridine, L2 = 2-(4-(pyridine-2-yl)-6-p  -tolylpyridin-2-yl)pyridine) were designed and synthesized as anti-cancer drugs. All complexes were structurally characterized by X-ray crystallography showing that three complexes were the mononuclear compounds with the triclinic crystal system p1¯ space group. The interaction between each of these three complexes and calf thymus DNA (CT-DNA) was investigated via spectroscopic techniques and viscosity measurement, which indicated that these complexes could bind to CT-DNA by intercalation. Moreover, DNA cleavage experiment showed that, in the natural light under an aerobic environment, all complexes could cleave DNA in the absence of exogenous oxidant agent, and that singlet oxygen (1O2) might serve as the major cleavage active species. Protein binding experiment indicated that 1–3 could bind to bovine serum albumin (BSA) with moderate bonding via the static quenching mechanism. In addition, the IC50 values of these three complexes were significantly lower which denoted highly anti-cancer activities in comparison to cisplatin. And each of these complexes could individually inhibit proliferation potential of cancer cells by promoting G1-phase cell cycle arrest (G1 arrest) and inducing apoptosis through the production of reactive oxygen species (ROS) and the activation of caspase-3Three Copper(II) complexes with two isomers of terpyridyl ligands could bind to DNA/BSA and exhibited good DNA cleavage activity, which arrested cells at the G0/G1 phase. And the generation of 1O2, ROS, was under the natural light in an aerobic environment, which activated the caspase family mediated mitochondrial apoptotic pathway.

The employment of a reduced Schiff-base ligand, 1,3-bis(3-methoxy-salicylamino)-2-propanol (H3L), with the assistance of acetate anions led to the isolation of eight heptanuclear heterometallic complexes containing [Cu5Ln2] cores. Single-crystal X-ray diffraction analyses have been performed for all the complexes and show that they all have dicationic [Cu5Ln2] cores with two nitrate or hexafluorophosphate anions to compensate the charge. The dicationic parts in 1–8 display centrosymmetric hexagonal-like arrangements in which one CuII ion sits on the inversion centre with six peripheral metal ions (two LnIII and four CuII) around it. The magnetic susceptibilities of all the complexes have been studied by dc magnetic measurements. The temperature dependent magnetic susceptibility data for the CuII–GdIII complex have been processed using PHI software. The results reveal that the magnetic exchange interactions between CuII and CuII ions are antiferromagnetic while those between CuII and GdIII ions are ferromagnetic. The magnetostructural correlations reveal that the bridging angles of Cu–O–Cu and Cu–O–Gd greatly influence the magnetic coupling of CuII–CuII and CuII–GdIII, respectively. Further, ac susceptibility studies have been carried out for DyIII and TbIII complexes and HoIII derivatives. The complexes CuII–HoIII and CuII–TbIII show slow magnetization relaxation behaviour of an SMM.

Three series of NiII–LnIII complexes were synthesized with the general formulae [(μ3-CO3)2{Ni(HL)(CH3–CH2OH)Ln(CH3COO)}2]·2CH3CH2OH (1–6) (Ln = Tb (1), Dy (2), Ho (3), Er (4), Tm (5), Yb (6); H3L = N,N′-bis(3-methoxysalicylidene)-1,3-diamino-2-prop-anol), [Ni(HL)Ln(dbm)3]·CH3OH2·2CH2Cl2 (7–10) (Ln = Tb (7), Eu (8), Gd (9), Ho (10); Hdbm = 1,3-diphenyl-1,3-propanedione) and [Ni(HL)(H2O)(tfa)Ln(hfac)2] (11–15) (Ln = Tb (11), Dy (12), Eu (13), Gd (14), Ho (15); Hhfac = 1,1,1,5,5,5-hexafluoropentane-2,4-dione, tfa− = trifluoroacetate) using compartmental Schiff base ligands in conjunction with auxiliary ligands. For the NiII2LnIII2 series, the tetranuclear structure could be considered as two NiII–LnIII dinuclear subunits bridged by two carbonates derived from atmospheric carbon dioxide. The LnIII ions of complexes 1–6 were octa-coordinated with distorted triangular dodecahedral geometry, while the LnIII ions of the dinuclear complexes 7–15 were nona-coordinated with distorted muffin geometry. The magnetic properties of the three series complexes were studied using dc and ac magnetic measurements. For the NiII–GdIII complexes, the dc magnetic susceptibility measurements suggested the existence of the anticipated ferromagnetic interaction between NiII and GdIII ions. The fitting of the χMT vs. T data processed by PHI software provided the parameters g = 2.08 (J = +0.87 cm−1) for 9 and g = 2.02 (J = +1.83 cm−1) for 14. The interaction exchange was magneto-structurally correlated to the Ni–O–Gd angle (α) and Ni(μ-O)Gd dihedral angle (β). With an applied dc field, complexes 1 (Tb), 2 (Dy), 7 (Tb) and 12 (Dy) exhibited single magnetic relaxation with SMM parameters of Ueff/k = 13.60 K, 11.52 K, 7.69 K and 5.14 K, respectively. Analysis of the Cole–Cole plots for complexes 2 and 7 suggested that a single relaxation process was mainly involved in the relaxation process, with α values in the range of 0.37–0.17 and 0.14–0.11, respectively.

A multifunctional three-dimensional lanthanide metal–organic framework has been rationally constructed. Highly selective sensing of benzaldehyde and Cu2+ ions makes it a potential bifunctional sensor. Also, it could serve as a good candidate material for the removal of dyes from effluents based on the size exclusion.

Three types of lanthanide coordination polymers with the formulas [Ln(Habtc)(H2O)(DMA)]n (1–3) {Ln = Ho (1), Er (2), Tm (3)}, [Ln(Habtc)(H2O)2(DMF)]n (4–6) {Ln = Gd (4), Er (5), Tm (6)} and {[(CH3)2NH2][(H2abtc)2Ln(H2O)]·5H2O}n {Ln = Gd (7), Dy (8), Er (9), Tm (10)} were constructed under solvothermal conditions in the presence of 3,3′,5,5′-azobenzenetetracarboxylic acid (H4abtc). They have three structural types from 3D to 1D polymers. The structural features of the three types of Ln-CPs are as follows: 1–3 shows a three-dimensional (3D) framework with an sni-type topology. Compounds 4–6 form a 2D sheet-like extended structure and these sheets stack on each other to give a 3D supramolecular architecture. The structures of 7–10 can be described as 1D chains constructed from Ln3+ ions and H2abtc2− ligands. The versatile structures well exhibit the rich coordination chemistry of H4abtc and the coordination geometries of LnIII ions. In addition, the magnetic and luminescence properties of complex 8 were investigated. Luminescent selective and sensitive sensing of Cr3+ compared with other metal ions was investigated by using 8. Moreover, the 1D anionic lanthanide coordination polymer 10 presents highly selective adsorption of cationic dyes via ion-exchange processes. The results show that H4abtc is a good ligand for constructing CPs with varying structures and properties.

Two novel clusters [CoII14(μ6-O2−)(sbha)12(sba)2 (DMF)7(DMA)]·(DMF)8 (1) and [NiII14(μ6-O2−)(sbha)12(sba)2(DMF)8] (2) (sH2bha = 4-bromo-benzohydroximic acid; sHba = 4-bromobenzene carboxylic acid; DMF = N,N-dimethylformamide; DMA = dimethylamine) have been synthesized. The novel body-centred μ6-O2− bridged Co14 and Ni14 clusters are packed in distorted face-centered cubic (FCC) patterns with different symmetries. Magnetic studies confirmed the antiferromagnetic exchange interactions between magnetic centers.

Framework-isomeric three-dimensional (3D) Zn–Ln heterometallic metal–organic frameworks, {[Ln2Zn(abtc)2(H2O)4]·2H2O}∞ {Ln = Sm(1), Tb(2)}, were synthesized using a convenient solvothermal reaction. They can serve as excellent sensors for the specific identification of benzaldehyde and NO2− through a fluorescence quenching process.

A series of NiII, CoII, ZnII and CdII complexes 1–9 with polytopic Schiff base ligands have been synthesized. The single-crystal X-ray crystallography results show that tetranuclear complexes 1–6 have common face-shared defective dicubane cores, whereas trinuclear CdII complexes 7–9 are almost linear entities. Synthesis methods (solvent evaporation and hydrothermal synthesis), reaction conditions (pH, solvents and dosage) and coligands (azide, methanol, chloride and acetate) play vital roles in determining the final structure of the complexes and therefore their magnetic properties. In complexes 1–6, the terminal and central M2+ ions are connected through mixed bridges, μ-phenoxido/μ1,1,1-X and μ-Oalphatic/μ1,1,1-X, while central two M2+ ions are linked by double bridges, μ1,1,1-X (X = azido and methoxido groups for 1 and 2–6 respectively). For complex 1, two central NiII ions are connected through two μ1,1,1-N3− which is relatively less reported. For complexes 7–9, there are two kinds of CdII, the centre CdII ions are eight-coordinated with triangle dodecahedral geometries, while the two side CdII ions are six-coordinated with trigonal prism geometries using chlorides or acetates as terminal ligands. Magnetic susceptibility measurements (χM) for compounds 1–6 have been performed, and they reveal predominant ferromagnetic exchange interactions in CoII and NiII tetramers. The photoluminescence studies show that the ZnII complex 6 and three CdII complexes 7–9 have strong fluorescence, and the lifetimes are measured to be in the 102 nanosecond timescale.

•A three-dimensional lanthanide metal-organic framework has been synthesized.•Complex 1 exhibits dual functional detection benzyl alcohol and benzaldehyde among different aromatic molecules.•Complex 1 displays a turn-on luminescence sensing with respect to ethanol among different alcohol molecules.A 3D lanthanide MOF with formula [Sm2(abtc)1.5(H2O)3(DMA)]·H2O·DMA (1) has been successfully synthesized via solvothermal method. Luminescence studies reveal that 1 exhibits dual functional detection benzyl alcohol and benzaldehyde among different aromatic molecules. In addition, 1 displays a turn-on luminescence sensing with respect to ethanol among different alcohol molecules, which suggests that 1 is also a promising luminescent probe for high selective sensing of ethanol.

Four novel coordination polymers based on an unsymmetrical angular ligand, 4-(5-(pyridin-3-yl)-4H-1,2,4-triazol-3-yl) benzoic acid (H2L), namely, Co(HL)2(H2O)4 (1), {[Ni(HL)2(H2O)2]·2H2O}n (2), [Ni(HL)2(H2O)2]n (3), and [Zn2(HL)L(μ2-OH)]n (4) have been synthesized under hydrothermal conditions and characterized. Compounds 1–4 have totally different architectures. Compound 1 is 0D mononuclear molecule. Complex 2 displays a unique 1D chain structure. Complexes 3 and 4 show 2D network layers. These various architectures demonstrate the versatile coordination abilities of the pyridine-substituted triazolyl benzoate ligand. Variable-temperature magnetic susceptibility measurements in the range 2–300 K revealed the existence of antiferromagnetic interactions among the adjacent Ni ions in 3. Besides, the luminescence properties of 4 and ligand were also discussed.Four novel coordination polymers based on an unsymmetrical angular ligand, 4-(5-(pyridin-3-yl)-4H-1,2,4-triazol-3-yl) benzoic acid (H2L) have been prepared and characterized.

Mononuclear compound I ([Co(Ptia)2(H2O)4] • H2O) and 1D chain compound II ([Ni4(Cptia)4(H2O)12]∞) have been constructed from the new ditopic 1,2,3-trazol-based aromatic heterocyclic carboxylic ligand, 4-(4-carboxy-1H-1,2,3-triazol-1-yl) benzoic acid) (H2Cptia), under different pH conditions by using the hydrothermal method. Their structure was characterized by single crystal X-ray diffraction (СIF files CCDC nos. 1409531 (I) and 1409531 (II)), IR spectra, and elemental analysis. Compound I is a mononuclear compound. In II, two sets of parallel arrangement 1D chains orient in different directions. The results of their magnetic measurements display the antiferromagnetic interaction exists among the paramagnetic ions.

A self-assembled functionalized metal–organic nanotube, compound 1, has been hydrothermally synthesized using 5-(3-methyl-5-phenyl-4H-1, 2, 4-triazol-4-yl)isophthalic acid (H2L) with Zn(II) ions. Compound 1 possesses a one-dimensional (1D) nanotubular architecture. Luminescence studies show that compound 1 displays strong blue emission at room temperature. Benzene adsorption results show that the latter adsorbed benzene only on the outer walls, while the former adsorbed benzene also on the inner walls since the holes through the walls enabled benzene to reach the inner tubules.

A 1D anionic lanthanide coordination polymer {[(CH3)2NH2] [(H2abtc)2Ho(H2O)]}n (1) (H4abtc = 3,3′,5,5′-azobenzene-tetracarboxylic acid) has been synthesized under hydrothermal reaction conditions. The protonated [(CH3)2NH2]+ is generated from decomposed DMA during the reaction, and balances the negative charge of the framework. The as-obtained samples were characterized using single-crystal and powder X-ray diffraction and TGA. Interestingly, 1 can selectively capture cationic dye molecules from mixtures of dye molecules containing different charges in aqueous solutions. Furthermore, 1 exhibits a different adsorption efficiency toward different cationic dyes (crystal violet, rhodamine B, safranine T and methylene blue). Among the studied dyes, methylene blue has a higher adsorption efficiency in comparison to the others. Thus, complex 1 could serve as a good candidate material for the selective removal of cationic dyes during the treatment of wastewater.

•With same ligand, three structural difference complexes have been synthesized.•1, with two rare μ3 -η1, η1, η1-CrO42−  moieties, is a tetranuclear complex.•Complexes show effective DNA binding and cleavage activity.•Complexes could quench fluorescence of BSA in a static quenching process.•1 shows about 6-fold higher anticancer activity against HeLa cell than cisplatin.Three new Co(II) complexes, [Co4(L)2(μ3-CrO4)2](ClO4)2 · 2CH3CN (1), [Co2(L)(μ2-na)(H2O)](ClO4)2 (2) and [Co2(L)(μ2-ba)](ClO4)2 · 0.5CH3CN (3) (Hna = nicotinic acid, Hba = benzoic acid, HL = N,N,N′,N′-tetrakis (2-quinolylmethyl)-1,3-diaminopropan-2-ol), have been synthesized and characterized by various physicochemical techniques. The Co(II) centers are connected by endogenous alkoxy bridge from L− and various extrinsic auxiliary linkers, some of which display coordination number asymmetry (5, 6-coordinated for 1 and 2; 5, 5-coordinated for 3). It is worth mentioning that complex 1 contains two rare reported μ3-η1, η1, η1-CrO42−  moieties. Susceptibility data of three complexes indicated intramolecular antiferromagnetic coupling of high-spin Co(II) atoms with exchange integral values (J) − 14.94 cm− 1, − 11.26 cm− 1 and − 13.66 cm− 1 for 1, 2 and 3, respectively. Interaction of compounds with calf thymus DNA (CT-DNA) have been investigated by absorption spectral titration, ethidium bromide (EB) displacement assay and viscosity measurement, which revealed that compounds bound to CT-DNA with a moderate intercalative mode, accompanied the affinities order: 1 > 2 ≈ 3. Three complexes exhibit oxidative cleavage of pBR322 plasmid DNA including a reliance on H2O2 as the activator. Compound 1 demonstrates an increased DNA cleavage activity as compared with 2 and 3, which could degrade super coiled DNA (SC DNA) into nicked coiled DNA (NC DNA) in lower concentration (5 μM). Moreover, all compounds could quench the intrinsic fluorescence of bovine serum albumin (BSA) in a static quenching process. Complex 1 also shows higher anticancer activity than cisplatin with lower IC50 value of incubation for both 24 h and 48 h.The tetranuclear CoII complex, containing two rare μ3 -η1, η1, η1-CrO42−  moieties and bearing coordination number asymmetry, displays good DNA cleavage activity in a low concentration (5 μM) in the presence of H2O2.

Two new mononuclear complexes [CuL(η2-SO4)] (1) and [NiL(η-SO4)(H2O)2]·3(H2O)·CH3CH2OH (2), where L is bis(2-quinolinyl methyl) benzyl-amine, have been synthesized and characterized by X-ray crystallography, ESI-MS and elemental analysis techniques. Complex 1 possesses a distorted square pyramidal geometry while complex 2 possesses distorted octahedral geometry. Interestingly, 2 dissolves in DMF–H2O mixed solvent, while 1 shows good water solubility. Both electronic absorption and EB displacement assay show that these complexes could bind to CT-DNA through partial intercalation. Though the DNA-binding abilities of 1 and 2 are similar, their chemical nuclease activities exhibit a great difference. Under physiological conditions, 1 could effectively convert pBR322 plasmid DNA from Form I to Form II at about 50 μM without any external agent, which shows self-oxidation cleavage activity; however, 2 shows poor DNA cleavage activity at 75 μM even in the presence of H2O2. At the same time, 1 also displays about 11-fold potential than 2 against HeLa cells with IC50 values 6.89 μM (1) and 74.85 μM (2). The IC50 value of 1 is even lower than the widely used drug cisplatin. The redox activity of Cu(II) and Ni(II) may play a main role in the biological activity of the two complexes, but the exact mechanism is still unclear. In addition, interactions of complexes with BSA have also been explored by fluorescence and UV-visible spectroscopic methods. The results indicated that complexes could quench the intrinsic fluorescence of BSA in a static quenching process.

•A unique Ag–Cu mixed metal-based polymer [CuII(DMF)4](CN)2CuI2[Ag2(CN)4] has been synthesized.•The luminescent experiment indicated two peaks with maxima near 425 (Ag) and 660 nm (Cu).•The luminescent experiment of this polymer displays high-performance selectivity for Ca2 + and Zn2 + ions.A novel luminescent probe based on Ag–Cu mixed metal coordination polymer has been designed and synthesized. Luminescent experiment indicates two peaks with maxima near 425 (Ag) and 660 nm (Cu), which shows high selectivity to Ca2 + and Zn2 +.A novel luminescent probe based on Ag–Cu mixed metal coordination polymer has been designed and synthesized, which shows high selectivity to Ca2 + and Zn2 +.

A three-dimensional, highly symmetric, terpyridine-based, spherical complex was synthesized via the coordination of four novel, trisdentate ligands and six Ru2+ ions, and it exhibits excellent stability over a wide range of pH values (1–14). Structural confirmation was obtained by NMR and ESI-TWIM-MS.

A series of metal–organic framework {Ln(BCPBA)(H2O)}n {Ln = Nd (1), Sm (2), Eu (3), Tb (4), Dy (5)}; {[Ln(BCPBA)(H2O)](H2O)}n {Ln = Pr (6), Gd (7)} have been synthesized through the hydrothermal synthesis method. These compounds possess non-interpenetrating 3D networks with 10.1438 Å × 17.9149 Å rhombic channels along the [001] direction. The results of temperature-dependent magnetic susceptibility measurements indicate that compounds 4 and 7 exhibit LnIII⋯LnIII antiferromagnetic interactions, while compound 5 exhibits LnIII⋯LnIII ferromagnetic interactions. Frequency dependent out-of-phase signals were observed in alternating current (ac) magnetic susceptibility measurements which indicate that they have slow magnetic relaxation characteristics. The luminescent properties of 1, 2, 3, 4, and 5 are also discussed. Due to the good match between the lowest triplet state of the ligand and the resonant energy level of the lanthanide ion, compound 4 has longer fluorescence lifetime (τ1 = 400.0000 ms, τ2 = 1143.469 ms) and higher quantum yield (Φ = 42%) compared with other compounds.

Two water-soluble ternary copper(II) complexes of [Cu(L)Cl](ClO4) (1) and [Cu(L)Br2] (2) (L = (2-((quinolin-8-ylimino)methyl)pyridine)) were prepared and characterized by various physico-chemical techniques. Both 1 and 2 were structurally characterized by X-ray crystallography. The crystal structures show the presence of a distorted square-pyramidal CuN3Cl2 (1) or CuN3Br2 (2) geometry in which Schiff-base L acts as a neutral tridentate ligand. Both complexes present intermolecular π–π stacking interactions between quinoline and pyridine rings. The interaction of two complexes with CT-DNA (calf thymus-DNA) and BSA (bovine serum albumin) was studied by means of various spectroscopy methods, which revealed that 1 and 2 could interact with CT-DNA through intercalation mode, and could quench the intrinsic fluorescence of BSA in a static quenching process. Furthermore, the competition experiment using Hoechst 33258 indicated that two complexes may bind to CT-DNA by a minor groove. DNA cleavage experiments indicate that the complexes exhibit efficient DNA cleavage activities without any external agents, and hydroxyl radical (HO) and singlet oxygen (1O2) may serve as the major cleavage active species. Notably, the in vitro cytotoxicity of the complexes on three human tumor cells lines (HeLa, MCF-7, and A549) demonstrates that two compounds have broad-spectrum antitumor activity with quite low IC50 ranges of 0.43–1.85 μM. Based on the cell cycle experiments, 1 and 2 could delay or inhibit cell cycle progression through the S phase.The complexes exhibit efficient DNA cleavage activity without any external agents. They could quench the intrinsic fluorescence of BSA in a static quenching process.

The in situ hydrothermal reaction of 5-(4-carboxy-1H-1,2,3-triazol-1-yl)isophthalic acid (H3ctia) with M(NO3)2·nH2O (M = Cu, Ni) afforded two new coordination polymers, {[Cu4(tia)4(H2O)3]·H2O}n (1) and {Ni(H2O)6·[Ni2(ctia)2(H2O)6]·2H2O}n (2) (tia2− = 5-(1H-1,2,3-triazol-1-yl)isophthalate). X-ray structural analysis reveals complex 1 is an unusual 3D framework containing D4h paddle-wheel copper units and two kinds of mononuclear copper units, and its resulting structure can be rationalized as a new topology with the Schläfli symbol of {4.82}2{42.85.106.122}{82.10}2{83}2. Compound 2 displays a 1D zigzag chain structure. Strong antiferromagnetic interactions are observed among dinuclear units in complex 1. Interestingly, complex 2 exhibits spin-glass-like behaviour with the spin glass freezing temperature at 15.8 K. In addition, the thermal stability of these compounds was also studied.

•Three alkaline earth compounds with different structures were synthesized.•The luminescent spectra of compounds 1–3 exhibit different degree of redshift.•Compounds 2 and 3 can sensitize Tb(III) ion to exhibit its characteristic emission.Three alkaline earth (AE) coordination polymers, namely, [Mg(H2BCPBA)2(H2O)4]n (1), [Sr(HBCPBA)(H2O)2]n (2), [Ba(H2BCPBA)2]n (3), (H3BCPBA = 3,5-bi(4-carboxy-phenolxy)-ben-zoic acid) have been synthesized in mixed solvents under hydrothermal conditions. The single crystal analysis show 1 is mononuclear compound, which forms 3D supramolecular framework through H-bonding and π–π interaction. In compound 2, dinuclear Sr(II) subunits were connected by the tripod linkers to afford the 3D metal–organic framework. Compound 3 displays 3D structure and each Ba(II) center in the framework acts as a 4,8-connected binode to give a unique network with a Schläfli symbol of {44.62}2{48.618.82}. The solid-state luminescent spectra of complexes 1–3 reveals that all of them have different degree of redshift compared with free ligand. The experiments of sensitization to Eu(III) and Tb(III) are performed on these three compounds. The results show that 2 and 3 can sensitize Tb(III) ion to exhibit its characteristic green emission.Graphical abstractThree alkaline earth compounds with different structures were designed and synthesized through hydrothermal synthesis method. Their fluorescence emission spectra have some redshift compared with free ligand. Compounds 2 and 3 can be Tb3+ sensitizers.

•A rare copper cyanide coordination polymer has been hydrothermally synthesized.•A ({6.8.10}2{6.8^3.10^2}) topology in 1 is created.•The existence of a cyanide group in compound 1 may be due to the decomposition of acetonitrile.•The optical and catalytic properties have been investigated.One-pot solvothermal treatments of acetonitrile, water, LiOH, Cu(CH3COO)2·H2O and 3-(5-(pyridin-4-yl)-1H-1,2,4-triazol-3-yl)pyridine (HL) yielded a rare copper cyanide coordination polymer, [Cu2(L) (CN)]n (1). The existence of a cyanide group in compound 1 may be due to the decomposition of acetonitrile at the relatively high temperature (160 °C) and autogenous pressure of the reaction. Compound 1 has been characterized by single-crystal X-ray diffraction, XRPD, IR, and elemental analysis. Compound 1 is a 3D copper cyanide coordination polymer, and a ({6.8.10}2{6.8^3.10^2}) topology in 1 is created. In addition, the optical and catalytic properties have been investigated.

•A series of novel lanthanide-based coordination polymers have been synthesized.•Compound 1 (Tb) shows typical antiferromagnetic interaction.•Compound 2 (Dy) has ferromagnetic behavior.•Compound 1 (Tb) exhibits strong characteristic emissions in the visible region.•Compounds of 2, 4 and 6 display NIR luminescence upon irradiation at the ligand band.A series of novel lanthanide-based coordination polymers, [Ln(L)(atpa)(H2O)2]n·1.5nH2O (HL = 4-[3-methyl-5-(pyridin-4-yl)-1,2,4-triazol-4-yl]benzoic acid, H2atpa = 2-aminoterephthalic acid and Ln = Tb(1), Dy(2), Ho(3), Er(4), Tm(5), Yb(6)) have been hydrothermally synthesized and characterized by single-crystal X-ray diffraction, optical and magnetic measurements. Compounds 1–6 are isomorphous, which can be described as a 2D network based on Ln2(CO2)2 units. The magnetic properties of compound 1 (Tb) show typical antiferromagnetic interaction, while compound 2 (Dy) has ferromagnetic behavior. The room-temperature photoluminescence spectra of 1 exhibit strong characteristic emissions in the visible region, whereas compounds of Dy(2), Er(4) and Yb(6) display NIR luminescence upon irradiation at the ligand band.A series of novel lanthanide-based coordination polymers have been synthesized. Compound 1 (Tb) shows typical antiferromagnetic interaction. Compound 2 (Dy) has ferromagnetic behavior. Compound 1 (Tb) exhibits strong characteristic emissions in the visible region. Compounds of 2, 4 and 6 display NIR luminescence upon irradiation at the ligand band.

Three different structural metal-organic frameworks (MOFs), [Zn(HPIDC)]n (1), {[Zn3(PIDC)2(H2O)3]·0.5H2O}n (2), and [Zn(HPIDC)(H2O)]n (3), were hydrothermally synthesized and characterized by single-crystal X-ray diffraction, X-ray powder diffraction, circular dichroism spectrum, and thermogravimetric analysis (H3PIDC = 2-(pyridine-3-yl)-1H-imidazole-4, 5-dicarboxylic acid). Single crystal X-ray diffractions show that ligands H3PIDC are doubly deprotonated in complexes 1 and 3, while ligand H3PIDC is triply deprotonated in complex 2. The doubly deprotonated HPIDC2 − coordinates in the μ3 mode to generate 3D or 2D MOFs, displaying two coordination modes. The triply deprotonated HPIDC3 − coordinates in the μ4 mode to generate a 3D MOF. In 1 a (10^3) metal organic net was fabricated (srs SrSi2 topology). In 2, however, a ({6.8^2}{6^2.8^2.10^2}) framework was formed. In 3 a (8^2.10) metal organic net was fabricated. Complexes 1 and 3 are crystallized in the orthorhombic, a chiral space group (P212121). Complex 3 is a chiral compound. Solid-state fluorescence emission spectra: complex 1 shows stronger luminescence than complexes 2 and 3. Absolute quantum yield of complex 2 is 3.60%, which is larger than that of the ligand by more than almost 1.7 folds.Three different structural metal-organic frameworks (MOFs), [Zn(HPIDC)]n (1), {[Zn3(PIDC)2(H2O)3]·0.5H2O}n (2), and [Zn(HPIDC)(H2O)]n (3), were hydrothermally synthesized. Complexes 1 and 3 are crystallized in the orthorhombic, a chiral space group (P212121). Complex 3 is a chiral compound.Highlights► Three different structural complexes have been synthesized. ► Complexes 1 and 3 crystallized in the orthorhombic, a chiral space group (P212121). ► Complex 3 is a chiral compound. ► Complex 1 shows stronger luminescence than complexes 2 and 3.

A family of novel Co(II)–Ln(III) heterometallic coordination polymers [Ln2Co(tia)4(H2O)4]∞ (tia2– = 5-(1H-1,2,3-triazol-1-yl) isophthalate, Ln = La 1, Ce 2, Pr 3, Nd 4, Sm 5, Eu 6, Gd 7, Tb 8, Dy 9) have been synthesized through in situ ligand transformation reactions, in which 5-(4-carboxy-1H-1,2,3-triazol-1-yl) isophthalic acid (H3ctia) undergoes decarboxylation and double deprotonation to tia2–. X-ray structural analysis reveals that compounds 1–9 are isomorphous. The heterometallic Ln3+ and Co2+ ions are connected by the dianionic linker (tia2–) to form unique 3D heterometallic frameworks. Moreover, we have systematically investigated the magnetic behaviors and fluorescent properties of these compounds. The out-of-phase ac signals observed for 9 suggest slow magnetization relaxation, which is unusual in 3D coordination polymers, especially in 3D heterometallic frameworks. In NIR regions, complexes 3, 4, 5, and 9 show the characteristic luminescence of the corresponding Ln(III ions.

Three new metal–organic frameworks (MOFs), formulated as [Cd(tia)(H2O)2]n (1), [Cu(tia)(H2O)2]n (2) and {[Zn3(ctia)2·(H2O)8]·2H2O}n (3) (tia2− = 5-(1H-1,2,3-triazol-1-yl) isophthalate, ctia3− = 5-(4-carboxylato-1H-1,2,3-triazol-1-yl) isophthalate) have been synthesized under hydrothermal conditions and characterized. Single-crystal X-ray diffraction analysis reveals that complexes 1 and 2 show similar common 2D (6, 3) topology network layers and these layers are further connected by H-bonding interactions to form 3D supermolecular structures. Complex 3 displays a unique 1D ladder-like chain structure, in which parallel arrangements of Zn1 coordination chains are linked by SBUs (SBUs: Secondary Building Units) containing the Zn2 center. Magnetic measurements in the range 2–300 K have shown antiferromagnetic interactions among the adjacent copper ions in complex 2. Complexes 1 and 3 exhibit strong luminescent emissions in the solid state at room temperature.Graphical abstractHighlights► Three new metal–organic frameworks were synthesized and characterized. ► The SBUs bridge two parallel Zn coordination chains to afford a unique 1D ladder-like chain structure in complex 3. ► There is a stronger luminescent emission in compounds 1 and 3 compared to the free ligand. ► There are antiferromagnetic interactions among the adjacent copper ions in complex 2.

A family of 3D metal–organic frameworks Na2Ln2(ox)3(suc)·(H2O)2, (Ln = Nd 1, Eu 2, Gd 3, Tb 4, ox = oxalate, suc = succinate) have been hydrothermally synthesized by self-assembly of succinic, sodium oxalate and Ln3+. They were characterized by X-ray crystallography, revealing that they crystallize in monoclinic groupP21/c. Ln3+ cations adopt a 9-fold configuration. Ox ligands play a unique dual role. These salts bear extraordinary structural features which result from host–guest interactions. Ln3+ cations, ox anions and succinate anions construct a host 3D framework. Guest Na+ cations are connected by ox ligands to construct a 3D alkali metal guest lattice, which is incorporated in the host 3D framework. Na+ cations adopt a fairly rare 7-fold configuration. The host–guest interaction would be more evident when sodium oxalate is displaced by oxalic acid, leading to an open framework [Nd2(ox)(suc)2·(H2O)4]·4H2O (5), where Nd3+ cations are 8-fold. Complex 5 bears a layer-pillared 3D structure, orthorhombic groupFddd, distinct from that of complex 1. Their thermal behavior, luminescence properties, and magnetic properties have been studied.

Three inorganic–organic hybrids based on Keggin tungstophosphates and lanthanides, [Pr(NMP)6(PW12O40)]n (1), [Eu(NMP)6(PW12O40)]n (2), and [Er2(NMP)12(PW12O40)][PW12O40] (3) (NMP=N-methyl-2-pyrrolidone), have been synthesized and characterized by elemental analysis, IR, UV–vis, and single-crystal X-ray diffraction. Compounds 1 and 2 exhibit 1D infinite zigzag chain structures, while compound 3 exhibits an ionic asymmetric structure due to lanthanide contraction. The three compounds are all photochromic. The magnetic susceptibility for 1 measured over the range 2–300 K shows that there is the dominant antiferromagnetic interaction in the compound. The results of luminescent properties show that compound 2 displays an interesting selectivity for Zn2+ ions.A series of photochromic hybrids based on Keggin tungstophosphates and lanthanides have been synthesized and characterized by elemental analysis, IR, UV–vis, and single-crystal X-ray diffraction. Their photochromic, magnetic, and luminescent properties have been studied.

A new complex, [H3teta][Mo(CN)8] · H2O, (teta = 5,7,7,12,14,14-hexamethyl-1,4,8,11-tetra-azacyocloteradeca-4,11-diene), has been synthesized and characterized by IR spectrum, element analysis and single crystal X-ray diffraction: monoclinic, space group P2(1)/c with a = 10.8553(8) Å, b = 12.4854(8) Å, c = 22.6348(15) Å, α = 90.00°, β = 97.3080(10)°, γ = 90.00°, Mr = 609.63, v = 3042.8(4), Z = 4. There are one [H3teta]3+, one [Mo(CN)8]3− and one water molecule in the asymmetric unit. The complex is interconnected through hydrogen bond and formed into a 3D porous network.

Two copper complexes, [Cu(bpca)(4,4′-bpyH)(H2O)(ClO4)]ClO4·H2O (1) and [Cu4(bpca)4(mpba)]·3H2O (2) [bpca = N-2-pyridinylcarbonyl-2-pyridine-carboximidate; mpba = 1,3-phenylenebis(oxamate)] were synthesized and characterized by physico-chemical and spectroscopic techniques. Complex 1 crystallizes in the Triclinic P-1 space group while complex 2 is in the Monoclinic space group C2/c. Bpca acts as a tridentate ligand through its three nitrogen atoms in these species. They exhibit 2D supramolecular architectures through hydrogen bonds and short-distance intermolecular interactions. Magnetic measurements in the range 2–300 K have shown weak antiferromagnetic interactions between the adjacent copper ions in complex 2.

A series of NiII, CoII, ZnII and CdII complexes 1–9 with polytopic Schiff base ligands have been synthesized. The single-crystal X-ray crystallography results show that tetranuclear complexes 1–6 have common face-shared defective dicubane cores, whereas trinuclear CdII complexes 7–9 are almost linear entities. Synthesis methods (solvent evaporation and hydrothermal synthesis), reaction conditions (pH, solvents and dosage) and coligands (azide, methanol, chloride and acetate) play vital roles in determining the final structure of the complexes and therefore their magnetic properties. In complexes 1–6, the terminal and central M2+ ions are connected through mixed bridges, μ-phenoxido/μ1,1,1-X and μ-Oalphatic/μ1,1,1-X, while central two M2+ ions are linked by double bridges, μ1,1,1-X (X = azido and methoxido groups for 1 and 2–6 respectively). For complex 1, two central NiII ions are connected through two μ1,1,1-N3− which is relatively less reported. For complexes 7–9, there are two kinds of CdII, the centre CdII ions are eight-coordinated with triangle dodecahedral geometries, while the two side CdII ions are six-coordinated with trigonal prism geometries using chlorides or acetates as terminal ligands. Magnetic susceptibility measurements (χM) for compounds 1–6 have been performed, and they reveal predominant ferromagnetic exchange interactions in CoII and NiII tetramers. The photoluminescence studies show that the ZnII complex 6 and three CdII complexes 7–9 have strong fluorescence, and the lifetimes are measured to be in the 102 nanosecond timescale.

Two novel clusters [CoII14(μ6-O2−)(sbha)12(sba)2 (DMF)7(DMA)]·(DMF)8 (1) and [NiII14(μ6-O2−)(sbha)12(sba)2(DMF)8] (2) (sH2bha = 4-bromo-benzohydroximic acid; sHba = 4-bromobenzene carboxylic acid; DMF = N,N-dimethylformamide; DMA = dimethylamine) have been synthesized. The novel body-centred μ6-O2− bridged Co14 and Ni14 clusters are packed in distorted face-centered cubic (FCC) patterns with different symmetries. Magnetic studies confirmed the antiferromagnetic exchange interactions between magnetic centers.

Framework-isomeric three-dimensional (3D) Zn–Ln heterometallic metal–organic frameworks, {[Ln2Zn(abtc)2(H2O)4]·2H2O}∞ {Ln = Sm(1), Tb(2)}, were synthesized using a convenient solvothermal reaction. They can serve as excellent sensors for the specific identification of benzaldehyde and NO2− through a fluorescence quenching process.

A series of metal–organic framework {Ln(BCPBA)(H2O)}n {Ln = Nd (1), Sm (2), Eu (3), Tb (4), Dy (5)}; {[Ln(BCPBA)(H2O)](H2O)}n {Ln = Pr (6), Gd (7)} have been synthesized through the hydrothermal synthesis method. These compounds possess non-interpenetrating 3D networks with 10.1438 Å × 17.9149 Å rhombic channels along the [001] direction. The results of temperature-dependent magnetic susceptibility measurements indicate that compounds 4 and 7 exhibit LnIII⋯LnIII antiferromagnetic interactions, while compound 5 exhibits LnIII⋯LnIII ferromagnetic interactions. Frequency dependent out-of-phase signals were observed in alternating current (ac) magnetic susceptibility measurements which indicate that they have slow magnetic relaxation characteristics. The luminescent properties of 1, 2, 3, 4, and 5 are also discussed. Due to the good match between the lowest triplet state of the ligand and the resonant energy level of the lanthanide ion, compound 4 has longer fluorescence lifetime (τ1 = 400.0000 ms, τ2 = 1143.469 ms) and higher quantum yield (Φ = 42%) compared with other compounds.

A 1D anionic lanthanide coordination polymer {[(CH3)2NH2] [(H2abtc)2Ho(H2O)]}n (1) (H4abtc = 3,3′,5,5′-azobenzene-tetracarboxylic acid) has been synthesized under hydrothermal reaction conditions. The protonated [(CH3)2NH2]+ is generated from decomposed DMA during the reaction, and balances the negative charge of the framework. The as-obtained samples were characterized using single-crystal and powder X-ray diffraction and TGA. Interestingly, 1 can selectively capture cationic dye molecules from mixtures of dye molecules containing different charges in aqueous solutions. Furthermore, 1 exhibits a different adsorption efficiency toward different cationic dyes (crystal violet, rhodamine B, safranine T and methylene blue). Among the studied dyes, methylene blue has a higher adsorption efficiency in comparison to the others. Thus, complex 1 could serve as a good candidate material for the selective removal of cationic dyes during the treatment of wastewater.