Syntheses,Structures, and Catalytic Properties of Three Copper(II) Coordination Polymers Based on 2,3,5,6‐Tetrafluoro‐1,4‐bis(triazole‐ylmethyl)benzene and Benzene Carboxylate Ligands

Three new mixed‐ligand coordination polymers of Cu^II, namely, [Cu(Fbtx)(L1)(H₂O)]_n ( 1 ), [Cu(Fbtx)_0.5(HL2)(H₂O)₂]_n ( 2 ), and {[Cu(Fbtx)_1.5(HL3)(H₂O)] · H₂O}_n ( 3 ) [Fbtx = 2,3,5,6‐tetrafluoro‐1,4‐bis(1,2,4‐triazole‐1‐ylmethyl)benenze, H₂L1 = terephthalic acid, H₃L2 = trimesic acid, NaH₂L3 = 5‐sulfoisophthalic acid monosodium salt], were hydrothermally synthesized and structurally characterized by elemental analysis, IR spectra, and single‐crystal and powder X‐ray diffraction techniques. All the complexes have a two‐dimensional (2D) coordination layer structure. Of these, 1 displays a planar 4⁴‐ sql structure whereas both 2 and 3 are highly undulated 6³‐ hcb nets. Moreover, their thermal stability and catalytic behaviors in the aerobic oxidation of 4‐methoxybenzyl alcohol were also investigated as well. The results indicate that the benzene dicarboxylate ligands have an effective influence on the structures and catalytic properties of the resulting coordination polymers.     

Influence of Flexible Bis(benzimidazole) Derivatives on the Self‐assembly of Three Mixed Ligands Silver(I) Coordination Polymers

Three silver(I) coordination polymers namely, [Ag₄(L1)₂(1, 4‐ndc)₂]_n ( 1 ) {[Ag(L2)] · (1, 4‐Hndc) · H₂O}_n ( 2 ), and {[Ag(L3)(H₂O)] · (1, 4‐Hndc)}_n ( 3 ) [L1 = 1, 3‐bis(benzimidazol‐1‐ylmethyl)benzene, 1, 4‐H₂ndc = 1, 4‐naphthalenedicarboxylic acid, L2 = 1, 3‐bis(5, 6‐dimethylbenzimidazole‐1‐ylmethyl)benzene, L3 = 1, 4‐bis(5, 6‐dimethylbenzimidazole)butane], were hydrothermally synthesized and characterized by single‐crystal X‐ray diffraction analysis, elemental analysis, IR spectroscopy, thermogravimetric and XRPD analysis. Complex 1 displays a 1D tube‐like chain, which is packed into a 3D supramolecular network by π–π stacking interactions. Complex 2 features an infinite 1D linear chain. Complex 3 contains a 1D wave‐like chain, which is extended into a 3D supramolecular network through O–H ··· O hydrogen bonding interactions. Moreover, these coordination polymers exhibit catalytic properties for degradation of methyl orange in Fenton‐like processes.     

Hydrothermal Synthesis of Five New Coordination Polymers Based on Benzophenone‐2, 4′‐dicarboxylic Acid and N‐Donor Spacers

Five new coordination polymers, namely, [Ni₂(L)₂(4, 4′‐bipy)₃)] · H₂O]_n ( 1 ), [Ni₂(L)₂(O) (bpp)₂]_n ( 2 ), [Zn(L)(bib)_0.5]_n ( 3 ), [Zn(L)(PyBIm)]_n ( 4 ), and [Zn₃(L)₂(OH)(im)]_n ( 5 ) [H₂L = benzophenone‐2, 4′‐dicarboxylic acid, 4, 4′‐bipy = 4, 4′‐bipyridine, bpp = 1, 3‐bis(4‐pyridyl)propane, PyBIm = 2‐(4‐pyridyl)benzimidazole, and im = imidazole] were synthesized under hydrothermal conditions. Structure determination revealed that compound 1 is a 3D network and exhibits a 4‐connected metal‐organic framework with (4².6³.8) topology, whereas compounds 2 , 3 , 4 , and 5 are two‐dimensional layer structures. In compounds 2 – 4 , dinuclear metal clusters are formed through carboxylic groups. In compound 5 , trinuclear metal clusters are formed through μ₃‐OH and carboxylic groups. The carboxylic groups exhibit three coordination modes in compounds 1 – 5 : monodentately, bidentate‐chelating, and bis‐monodentately. Furthermore, the luminescent properties for compounds 3 , 4 , and 5 were investigated.     

Six Coordination Polymers based on 4‐(1H‐Imidazol‐1‐yl)phthalic Acid: Structural Diversities,Magnetism and Luminescence Properties

The coordination polymers (CPs), [Ni(L)(H₂O)₄]_n ( 1 ), [Co(HL)₂(H₂O)₂]_n ( 2 ), {[Cu(L)(H₂O)₃] · H₂O}_n ( 3 ), [Mn(L)(H₂O)₂]_n ( 4 ), [Cd(L)(H₂O)₂]_n ( 5 ), and {[Zn₂(L)₂] · H₂O}_n ( 6 ), were solvothermally synthesized by employing the imidazol‐carboxyl bifunctional ligand 4‐(1H‐imidazol‐1‐yl) phthalic acid (H₂L). Single‐crystal X‐ray diffraction indicated that the L^2–/HL^– ligands display various coordination modes with different metal ions in 1 – 6 . Complexes 1 and 2 show one‐dimensional (1D) chain structures, whereas complexes 3 – 6 show 2D layered structures. The magnetic properties of these complexes were investigated. Complexes 1 and 3 indicate weak ferromagnetic interactions, whereas complexes 2 and 4 demonstrate antiferromagnetic interactions. In addition, luminescence properties of 5 and 6 were measured and studied in detail.     

Heterometallic SrII‐MII (M=Co,Ni, Zn and Cu) Coordination Polymers: Synthesis,Temperature‐Dependent Structural Transformation,and Luminescent and Magnetic Properties

The use of pyridine‐2,4‐dicarboxylic acid (H₂pydc) in the construction of Sr^II and Sr^II‐M^II (M=Co, Ni, Zn and Cu) coordination polymers is reported. Eight complexes, that is, [Sr(pydc)H₂O]_n ( 1 ), [MSr(pydc)₂(H₂O)₂]_n (M=Co ( 2 ), Ni ( 3 ), Zn ( 4 )), [ZnSr(pydc)₂(H₂O)₇]_n?4 nH₂O ( 5 ), [SrCu(pydc)₂]_n ( 6 ), [SrCu(pydc)₂(H₂O)₃]_n?2 nH₂O ( 7 ), and [Cu₃Sr₂(pydc)₄(Hpydc)₂(H₂O)₂]_n ( 8 ), have been synthesized via dexterously choosing the appropriate strontium sources and transition metal salts, and rationally controlling the temperature of the reaction systems. Complexes 1 , 2 ( 3 , 4 ), 6 , and 8 display four types of 3‐D framework structures. Complexes 5 and 7 exhibit a 2‐D network and a 1‐D chain structure, respectively. The 2‐D complex 7 can be reversibly transformed into 3‐D compound 6 through temperature‐induced solvent‐mediated structural transformation. The luminescent property studies indicated that complex 1 shows a strong purple luminescent emission and 4 exhibits a strong violet luminescence emission. The magnetic properties of 2 , 3 , and 8 were also studied. Antiferromagnetic M^II???M^II interactions were determined for these complexes.     

Three Silver(I) Coordination Polymers Constructed from Flexible Bis(benzimidazole) and Carboxylates Ligands

Under hydrothermal conditions, three new Ag^I coordination polymers, [Ag(L1)(Hmip)]_n ( 1 ), [Ag(L2)_0.5(ndc)_0.5]_n ( 2 ), and {[Ag(L3)_0.5(Htbi)] · 0.25H₂O}_n ( 3 ) [H₂mip = 5‐methylisophthalic acid, L1 = 1,4‐bis(2‐methylbenzimidazol‐1‐ylmethyl)benzene, H₂ndc = 2,6‐naphthalenedicarboxylic acid, L2 = 1,3‐bis(2‐methylbenzimidazol‐1‐ylmethyl)benzene, H₂tbi = 5‐tert‐butyl isophthalic acid, L3 = 1,4‐bis(5,6‐dimethylbenzimidazole)butane] were synthesized by employing flexible bis(benzimidazole) and dicarboxylic acid ligands. Polymer 1 displays a 2D 4‐connected 4L2 underlying net topology with the point symbol of (6⁵.8) in standard representation. Compound 2 possesses a 2D uninodal 4‐connected Shubnikov tetragonal plane net (sql) based on a dinuclear Ag^I clusters with the point symbol (4⁴.6²), which is further extended into a 3D supramolecular framework by π–π interactions. Compound 3 possesses dinuclear molecular complex groups, which form chains by weak Ag–O (2.6 Å) coordination bonds, and further assembled into a 2D supramolecular layer by hydrogen bonds and π–π stacking interactions. These complexes exhibit intense fluorescent emissions in solid state. UV/Vis diffuse reflection spectra and the excellent catalytic activity for the degradation of the congo red azo dye in a Fenton‐like process are discussed.     

Syntheses, Structures and Thermal Stabilities of Three Novel Lanthanide Coordination Polymers with 6-Hydroxynicotinic Acid

Three novel lanthanide coordination polymers {[Ce₂(HOnic)₄(Onic)₂(H₂O)₂]·6H₂O}_n ( 1 ), {[Ln(HOnic)(Onic)‐ (H₂O)₅·(HOnicH)]·H₂O}_n [HOnicH=6‐hydroxynicotinic acid, Ln=Nd ( 2 ), Pr ( 3 )] have been synthesized and characterized by elemental analyses, IR spectrum and single crystal X‐ray diffraction. Structure analyses reveal that 1 features a 2D plane structure while compounds 2 and 3 possess a 1D chain‐like polymeric structure. TG analyses indicate that 1 exhibits higher thermostability than 2 and 3 , which was attributed to the layer polymeric structure of 1 .     

Assembled synthesis of luminescent mono/double‐layered 2D and 3D Zn (II)‐based coordination polymers tuned by flexible bis (pyridyl)propane‐1,2‐diamines and diverse organic dicarboxylates

Six mono/double‐layered 2D and three 3D coordination polymers were synthesized by a self‐assembly reaction of Zn (II) salts, organic dicarboxylic acids and L1/L2 ligands. These polymeric formulas are named as [Zn(L1)(C₄H₂O₄)_0.5 (H₂O)]_n·0.5n(C₄H₂O₄)·2nH₂O ( 1 ), [Zn₂(L2)(C₄H₂O₄)₂]_n·2nH₂O ( 2 ), [Zn(L1)(m‐BDC)]_n ( 3 ), [Zn₂(L2)(m‐BDC)₂]_n·2nH₂O ( 4 ), [Zn₃(L1)₂(p‐BDC)₃(H₂O)₄]_n·2nH₂O ( 5 ), [Zn₂(OH)(L2) (p‐BDC)_1.5]_n ( 6 ), [Zn₂(L1)(p‐BDC)₂]_n·5nH₂O ( 7 ), [Zn₂(L2)(p‐BDC)₂]_n·3nH₂O ( 8 ) and [Zn₂(L1)(C₄H₄O₄)_1.5(H₂O)]_n·n(ClO₄)·nH₂O ( 9 ) [L1 = N,N′‐bis (pyridin‐4‐ylmethyl)propane‐1,2‐diamine, L2 = N,N′‐bis (pyridin‐3‐ylmethyl)propane‐1,2‐ diamine, m‐BDC^2? = m‐benzene dicarboxylate, p‐BDC^2? = p‐benzene dicarboxylate]. Meanwhile, these polymers have been characterized by elemental analysis, infrared, thermogravimetry (TG), photoluminescence, powder and single‐crystal X‐ray diffraction. Polymers 1–6 present mono‐ and double (4,4)‐layer motifs accomplished by L1/L2 ligands with diverse conformations and organic dicarboxylates, and the layer thickness locates in the range of 5.8–15.0 Å. In three 3D polymers, the L1 and L2 molecules adopt the same cis‐conformations and join adjacent Zn (II) cations together with p‐BDC^2? or succinate, giving rise to different binodal (4,4)‐c nets with (4.5².8³)(4.5³.7²) ( 7 ), pts ( 8 ) topology and twofold interpenetrated binodal (5,5)‐c nets with (3².4⁴.5².6²)(3.4³.5².6⁴) ( 9 ). Therefore, the diverse conformations of the two bis (pyridyl)‐propane‐1,2‐diamines and the feature of different organic dicarboxylate can effectively influence the architectures of these polymers. Powder X‐ray diffraction patterns demonstrate that these bulk solid polymers are pure phase. TG analyses indicate that these polymers have certain thermal stability. Luminescent investigation reveals that the emission maximum of these polymers varies from 402 to 449 nm in the solid state at room temperature. Moreover, 1 , 3 and 5–8 show average luminescence lifetimes from 8.81 to 16.30 ns.     

Homo‐ and Heteronuclear Compounds with a Symmetrical Bis‐hydrazone Ligand: Synthesis,Structural Studies,and Luminescent Properties

Nine new coordination compounds have been synthesized by the reaction of salts of bivalent metal ions (a=Zn^II, b=Cu^II, c=Ni^II, d=Co^II) with the bis(benzoylhydrazone) derivative of 4,6‐diacetylresorcinol (H₄L). Three kinds of complexes have been obtained: homodinuclear compounds [M₂(H₂L)₂]?nH₂O ( 1 a , 1 b , 1 c , and 1 d ), homotetranuclear compounds [M₄(L)₂]?n(solv) ( 2 a and 2 c ), and heterotetranuclear compounds [Zn₂M₂(L)₂]?n(solv) ( 2 ab , 2 ac , and 2 ad ). The structures of the free ligand H₄L?2 DMSO and its complexes [Zn₂(H₂L)₂(DMSO)₂] ( 1 a* ), [Zn₄(L)₂(DMSO)₆] ( 2 a* ), and [Zn_0.45Cu_3.55(L)₂(DMSO)₆]?2 DMSO ( 2 ab* ) were elucidated by single‐crystal X‐ray diffraction. The ligand shows luminescence properties and its fluorimetric behavior towards M^II metals (M=Zn, Cu, Ni and Co) has been studied. Furthermore, the solid‐state luminescence properties of the ligand and compounds have been determined at room temperature. ¹H NMR spectroscopic monitoring of the reaction of H₄L with Zn^II showed the deprotonation sequence of the OH/NH groups upon metal coordination. Heteronuclear reactions have also been monitored by using ESI‐MS and spectrofluorimetric techniques.     

Hydrothermal Synthesis,Crystal Structures,and Catalytic Properties of Three Coordination Polymers Containing ­Flexible Bis(benzimidazole) and Dicarboxylate Ligands

Three metal‐organic coordination polymers, namely {[Cd(L1)(1,2‐chdc)] · 2H₂O}_n ( 1 ), {[Ni(L2)(1,2‐chdc)] · H₂O}_n ( 2 ), and [Cd(L2)(npht)]_n ( 3 ) [L1 = 1,2‐bis(2‐methylbenzimidazol‐1‐ylmethyl)benzene, L2 = 1,2‐bis(5,6‐dimethylbenzimidazol‐1‐ylmethyl)benzene, 1,2‐H₂chdc = 1,2‐cyclohexanedicarboxylic acid, H₂npht = 3‐nitrophthalic acid] were synthesized under hydrothermal conditions and structurally characterized by single‐crystal X‐ray diffraction methods, IR spectroscopy, TGA, and elemental analysis. In compound 1 , two 1,2‐chdc^2– ligands connect two neighboring Cd atoms to form a dinuclear [Cd₂(1,2‐chdc)₂] subunit, which is further linked by L1 ligands to construct a 1D ladder‐like chain. Compound 2 exhibits a 2D (4,4) coordination network with {4⁴.6²} topology, whilst compound 3 shows a 1D helical chain structure. The fluorescence, UV/Vis diffuse reflection spectra, and catalytic properties of complexes 1 – 3 for the degradation of the congo red azo dye in a Fenton‐like process are investigated.     

Syntheses, Supramolecular Structures and Antibacterial Activities of Five Helical Transition Complexes with 5-Chloro-1-phenyl-1H-pyrazole-3,4-dicarboxylic Acid

Five new transition metal complexes [Cu(HL)₂(H₂O)₂] ( 1 ), [Cu(HL)₂(phen)] ( 2 ), [Cu(HL)₂(H₂O)]₂(4,4′‐bipy) ( 3 ), [Zn(HL)₂(H₂O)₂]·(4,4′‐bipy) ( 4 ), [Ag(HL)(4,4′‐bipy)]_n ( 5 ), (H₂L=5‐chloro‐1‐phenyl‐1H‐pyrazole‐3,4‐dicarboxylic acid, phen=1,10‐phenanthroline; 4,4′‐bipy=4,4′‐bipyridine) have been synthesized and characterized. Complexes 1 , 2 and 4 exhibit monomeric structures, 3 shows a dinuclear structure, 5 displays 1D chain structure, and all extend to 3D supramolecular network via rich hydrogen bonds. Complexes 1 , 2 , 3 , 5 comprise single helical chains, while complex 4 generates quadruple‐stranded helical chains. Furthermore, the antibacterial activities of the titled complexes against bacterial species, three Gram positive bacteria (Staphylococcus aureus, Bacillus subtilis and Candida albicans) and two Gram negative bacteria (Escherichia coli and Pseudomonas aeruginosa) were studied and compared to the activities of free ligands by using the microdilution method.     

Syntheses and Crystal Structures of LnIII–CuI Coordination Polymers

Four three‐dimensional heterometallic coordination polymers, [Ln₂Cu₄I₃(IN)₇(H₂O)]_n ( 1 , 2 ) and [LnCu_3.5I₃(IN)_3.5(H₂O)₃]_n · nH₂O ( 3 , 4 ) [HIN = isonicotinic acid, Ln = Nd ( 1 ), Gd ( 2 ), La ( 3 ), Eu ( 4 )] were hydrothermally synthesized by using lanthanide oxides, isonicotinic acid, copper chloride, and potassium iodide. The different molar ratio of raw materials results in two distinct types of three‐dimensional frameworks of compounds 1 – 4 . The structure of compounds 1 and 2 are constructed by the layer modules of [Ln₂(IN)₇(H₂O)]_n^n– and Cu₄I₃ clusters, whereas that of compounds 3 and 4 are built by dimeric Ln₂(IN)₆(H₂O)₆ and layered polymeric [Cu₇I₆]_nⁿ⁺ units.     

Structural Diversity of Copper(II) Coordination Polymers Based on Tosylated Isophthalic Ligands

Two tosylated isophthalic ligands, namely, 5‐tosyloxy‐isophthalic acid (H₂toip) and 5‐tosylamino‐isophthalic acid (H₂taip) were synthesized. Self‐assembly of Cu^II ions with H₂toip and H₂taip ligands under different reaction conditions (temperature, solvents, and auxiliary ligands) gave rise to three coordination polymers formulated as [Cu(toip)(py)₂]_n ( 1 ), [Cu₆(toip)₆(H₂O)₆]_n · 8n(H₂O) ( 2 ), and [Cu₆(taip)₆(py)₄(dmf)₂]_n · n[(dmf)₆(MeOH)₂(H₂O)₂] ( 3 ) (py = pyridine, dmf = dimethylformamide). Compound 1 is a one‐dimensional (1D) coordination polymeric chain. Compounds 2 and 3 are two‐dimensional (2D) coordination networks featuring very similar Kagomé lattices based on the interconnection of paddle‐wheel [Cu₂(COO)₄] secondary building units (SBUs) and toip^2–/taip^2– ligands. However, the arrangement of adjacent Kagomé lattices in 2 and 3 are distinct, making them crystallize in different space groups and thereby have different crystal structures.     

Synthesis and Characterization of Two Distinct 2D Nickel(II) Coordination Polymers From Dicarboxylate and Flexible Bis(imidazole) Ligands

Two nickel(II) coordination polymers, formulated as {[Ni₂(bix)₂(tbta)₂(H₂O)₄] · 0.25H₂O}_n ( 1 ) and [Ni₂(bix)(aip)₂(H₂O)₂]_n ( 2 ) [bix = 1, 4‐bis(imidazol‐1‐ylmethyl)benzene, H₂tbta = tetrabromoterephthalic acid, H₂aip = 5‐aminoisophthalic acid] were synthesized under hydrothermal conditions and structurally characterized by single‐crystal X‐ray diffraction methods, IR spectroscopy, TGA, and elemental analysis. Complex 1 exhibits a 2D (4, 4) layer with {4⁴.6²} topology. Complex 2 shows 2D (3, 4)‐connected 3 , 4L83 sheets, which are finally extended into an unusual (5, 6)‐connected 3D supramolecular network by classic hydrogen bond interactions. Fluorescence, UV/Vis diffuse reflection spectra, and catalytic properties of two complexes for the degradation of the methyl orange dye in a photo‐Fenton‐like process were investigated.     

2D l‐Di‐toluoyl‐tartaric acid Lanthanide Coordination Polymers: Toward Single‐component White‐Light and NIR Luminescent Materials

A series of five l ‐di‐p‐toluoyl‐tartaric acid (l ‐DTTA) lanthanide coordination polymers, namely {[Ln₄K⁴ L₆(H₂O)_x]?yH₂O}_n, [Ln=Dy ( 1 ), x=24, y=12; Ln=Ho ( 2 ), x=23, y=12; Ln=Er ( 3 ), x=24, y=12; Ln=Yb ( 4 ), x=24, y=11; Ln=Lu ( 5 ), x=24, y=12] have been isolated by simple reactions of H₂L (H₂L= L ‐DTTA) with LnCl₃?6 H₂O at ambient temperature. X‐ray crystallographic analysis reveals that complexes 1 – 5 feature two‐dimensional (2D) network structures in which the Ln³⁺ ions are bridged by carboxylate groups of ligands in two unique coordinated modes. Luminescent spectra demonstrate that complex 1 realizes single‐component white‐light emission, while complexes 2 – 4 exhibit a characteristic near‐infrared (NIR) luminescence in the solid state at room temperature.     

Spin Frustration in a Family of Pillared Kagomé Layers of High‐Spin Cobalt(II) Ions

Based on the analogous kagomé [Co₃(imda)₂] layers (imda=imidazole‐4,5‐dicarboxylate), a family of pillar‐layered frameworks with the formula of [Co₃(imda)₂(L)₃] ? (L)_n ? xH₂O ( 1 : L=pyrazine, n=0, x=8; 2 : L=4,4′‐bipyridine, n=1, x=8; 3 : L=1,4‐di(pyridin‐4‐yl)benzene, n=1, x=13; 4 : L=4,4′‐di(pyridin‐4‐yl)‐1,1′‐biphenyl, n=1, x=14) have been successfully synthesized by a hydrothermal/solvothermal method. Single‐crystal structural analysis shows a significant increase in the interlayer distances synchronized with the extension of the pillar ligands, namely, 7.092(3) ( 1 ), 10.921(6) ( 2 ), 14.780(5) ( 3 ), and 19.165(4) Å ( 4 ). Despite the wrinkled kagomé layers in complexes 2 – 4 , comprehensive magnetic characterizations revealed weakening of interlayer magnetic interactions and an increase in the degree of frustration as the pillar ligand becomes longer from 1 to 4 ; this leads to characteristic magnetic ground states. For compound 4 , which has the longest interlayer distance, the interlayer interaction is so weak that the magnetic properties observed within the range of temperature measured would correspond to the frustrated layer.     

Coordination Frameworks based on 3,5‐Bis(imidazole‐1‐yl)­pyridine and Aromatic Dicarboxylate Ligands: Synthesis,Crystal Structures,and Photoluminescent Properties

Three metal coordination polymers [Zn(bdc)(L)(H₂O)]_n ( 1 ), [Co(pta)(L)(H₂O)₂]_n ( 2 ), and [Cd(tda)(L)(H₂O)]_n ( 3 ) [H₂bdc = 1,2‐benzene dicarboxylate acid, H₂pta = terephthalic acid, H₂tda = 2,5‐thiophenedicarboxylic acid, L = 3,5‐bis(imidazole‐1‐yl)pyridine] were synthesized and structurally characterized by IR spectroscopy, elemental analysis, X‐ray powder diffraction, and X‐ray single crystal diffraction. Complex 1 shows a three‐dimensional (3D) structure with cco topology with the symbol 6⁵ · 8, whereas complex 2 features a 3D structure with cds topology with the symbol 6⁵ · 8. Complex 3 has a 2D network constructed by the cadmium atoms bridged through the ligands tda and L. Their X‐ray powder diffraction patterns were compared with the simulated ones. Moreover, their luminescent properties were investigated in the solid state at room temperature, and the thermogravimetric analyses were carried out to study the thermal stability of the 3D networks.     

Synthesis,Structures, and Luminescent Properties of Three Alkaline Earth Metal‐based MOFs Assembled from 3‐(3‐Carboxyphenoxy) Phthalic Acid Ligand

Three two‐dimensional (2D) coordination complexes, namely [Ca₂(HL)₂(H₂O)₅]_n · 2nH₂O ( 1 ), [Sr(HL)(H₂O)₃]_n · nH₂O ( 2 ), and [Ba(HL)(H₂O)₃]_n · nH₂O ( 3 ) [H₃L = 3‐(3‐carboxy‐phenoxy) phthalic acid], were synthesized by using the ligand H₃L and alkaline earth metals. Structural analysis reveals that the structures of complexes 1 – 3 can be described as 2D networks with the point (Schälfli) symbol for net: {3¹² · 4¹⁴ · 5²} topology. Additionally, the thermal stability and solid‐state luminescent properties of compounds 1 – 3 were investigated at room temperature. The quantum yield (QY) of compound 2 is 10.75 %, which is much higher than the QY of the free H₃L ligand (QY_H3L < 1 %).     

Hydrothermal Syntheses and Characterizations of Three ZnII Coordination Polymers Tuned by pH Value and Base

Three new Zn^II coordination polymers, [Zn(bpe)(HL)₂(H₂O)]_n ( 1 ), {[Zn(bpe)(L)] · H₂O}_n ( 2 ), and [Zn₂Ca(bpe)(HL)₂(L)₂]_n ( 3 ) [H₂L = 5‐methoxyisophthalic acid and bpe = 1,2‐dis(4‐pyridyl) ethylene], were hydrothermally synthesized under different pH values and bases. Their structures were determined by single‐crystal X‐ray diffraction and further characterized by elemental analyses and IR spectroscopy. Polymer 1 is formed at pH = 4 and has a 1D chain structure. These 1D chains are linked by hydrogen bonds to afford a 1D double chain and further to form a threefold interpenetrating network. At pH = 7, a 2D layer structure of 2 with sql topology is formed. By using calcium hydroxide as base for the synthesis of 3 , a 3D network with pcu topology is obtained. These structural differences among 1 – 3 indicate that pH value and the identity of the base play important role in defining the overall structures of metal‐organic frameworks. In addition, the fluorescent properties of 1 – 3 are discussed.     

Four Complexes with the Rigid Ligand 1,4‐Bis(1H‐imidazol‐4‐yl)benzene and Varied Carboxylate Ligands

Four metal‐organic coordination polymers [Co₂(L)₃(nipa)₂]·6H₂O ( 1 ), [Cd(L)(nipa)]·3H₂O ( 2 ), [Co(L) (Hoxba)₂] ( 3 ) and [Ni₂(L)₂(oxba)₂(H₂O)]·1.5L·3H₂O ( 4 ) were synthesized by reactions of the corresponding metal(II) salts with the rigid ligand 1,4‐bis(1H‐imidazol‐4‐yl)benzene (L) and different derivatives of 5‐nitroisophthalic acid (H₂nipa) and 4,4′‐oxybis(benzoic acid) (H₂oxba), respectively. The structures of the complexes were characterized by elemental analysis, FT‐IR spectroscopy and single‐crystal X‐ray diffraction. Complexes 1 and 3 have the same one‐dimensional (1D) chain while 2 is a 6‐connected twofold interpenetrating three‐dimensional (3D) network with α ‐Po 4¹²·6³ topology based on the binuclear Cd^II subunits. Compound 4 features a puckered two‐dimensional (2D) (4,4) network, and the large voids of the packing 2D nets have accommodated the uncoordinated L guest molecules. An abundant of N–H···O, O–H···O and C–H···O hydrogen bonding interactions exist in complexes 1–4 , which contributes to stabilize the crystal structure and extend the low‐dimensional entities into high‐dimensional frameworks. Lastly, the photoluminiscent properties of compounds 2 were also investigated.