Coordination polymers from 1-D to 3-D assembled from disulfonate ligands: Structures and luminescent properties

Four rare earth organodisulfonate coordination polymers, {[Tb₂(phen)₄(nds)₃(H₂O)₂]·4H₂O}_n (1), {[Ln(phen)(nds)(OH)]}_n[Ln = Sm (2), Nd (3)], {[Tb(phen)₂(nds)_0.5(OH)·H₂O]·(nds)_0.5}_n (4), were synthesized under the solvothermal conditions by using ligands 2,6-naphthalenedisulfonate (L = nds) and 1,10-phenanthroline (L′ = phen). Single-crystal X-ray diffraction reveals that compounds 1 and 4 exhibit different 1-D and 2-D crystal structures just owing to the single difference of stoichiometric ratio of the reactants in the synthesis process. Compounds 2 and 3 show 3-D structures with similar Ln coordination mode. Besides, the photoluminescent property in solid state of 1 was investigated in detail.     

Controllable assembly of a 3-D metal–organic supramolecular framework with the inclusion of a well-resolved 1-D water morph

Two mixed-ligand metal–organic complexes [Cd₂(adipato)(phen)₂(NO₃)₂(H₂O)₂](H₂O)₆ (1) and {[Cd(adipato)(phen)](H₂O)₃}_n (2) have been synthesized upon the reaction of Cd(II) nitrate with 1,10-phenanthroline (phen) and adipate under similar conditions. For 1, the adipato-bridged dinuclear entities are extended into a 3-D supramolecular architecture via hydrogen bonds and π–π stacking. Interestingly, a well-resolved 1-D water morphology consisting of alternate cyclic water tetramer and hexamer is detected as the guests in each channel of this 3-D lattice. Whereas 2 represents a layered coordination polymer in which the Cd^II centers are interlinked by adipate dianions via different coordination modes.     

Novel Hg and Mn supramolecular complexes with a versatile building block 5-(4-pyridyl)-1,3,4-oxadiazole-2-thiolate involving in situ ligand formation

Reaction of potassium N′-(pyridine-4-carbonyl)-hydrazinecarbodithioate ([K⁺(H₂L)⁻]) with Hg^II or Mn^II inorganic salt in the presence of 1,10-phenanthroline (phen) or 4,4′-bipyridine (bipy), yields complexes [Hg(pyt)₂(phen)] (1) and {[Mn(pyt)₂(H₂O)₂]·(bipy)·(H₂O)₂}_n (2), in which the pyt ligand (Hpyt = 5-(4-pyridyl)-1,3,4-oxadiazole-2-thiol) is obtained by in situ ligand formation from the acyclic precursor [K⁺(H₂L)⁻]. Single crystal X-ray diffraction suggests that the pyt anionic ligands in 1 and 2 behave as thiolate and thione isomers, respectively, and display S- and μ-N_pyridyl, N_oxadiazole-binding fashions. Complex 1 shows a 1-D fishbone-like supramolecular array via strong aromatic stacking interactions between the discrete mononuclear coordination motifs, whereas 2 has a 2-D layered host coordination framework with the inclusion of bipy and water guests in the cavities.     

Ionothermal synthesis and characterization of a 3-D (4, 8)-connected porous anionic metal–organic framework entrapped with 1-D [K2(H2O)6] chains

A novel metal–organic coordination polymer, namely, {[K₂(H₂O)₆][Cd₃(1,2,4,5-BTC)₂]}_n (1) (1,2,4,5-BTC = 1,2,4,5-benzenetetracarboxylate), was synthesized in an ionothermal reaction by using an ionic liquid 1-ethyl-3-methylimidazolium bromide ([EMIM]Br) as solvent. Complex 1 features a novel 3-D (4, 8)-connected porous anionic architecture constructed by linking trinuclear Cd subunits with 1,2,4,5-BTC⁴⁻ ligands, which are further filled with 1-D [K₂(H₂O)₆] cationic chains.     

Solvothermal synthesis of 1D and 2D cobalt(II) and nickel(II) coordination polymers with 2,5-dihydroxy-p-benzenediacetic acid

1D cobalt(II) and nickel(II) coordination polymers {[Co(dba)(H₂O)₄] · H₂O}_n (1) and {[Ni(dba)(H₂O)₄] · H₂O}_n (2) (H₂dba = 2,5-dihydroxy-p-benzenediacetic acid) were synthesized under low temperature solvothermal condition. When 4,4′-bipyridine (bpy) was introduced to the synthetic systems of 1 and 2, respectively, two novel 2D coordination polymers {[Co(dba)(bpy)] · 0.5H₂O}_n (3) and [Ni(dba)(bpy)(H₂O)₂]_n (4) with different structures were obtained. All of the compounds were characterized by elemental analysis, FT-IR, UV–Vis spectra and single crystal X-ray diffraction.     

Two novel Zn(II) coordination polymers based on trigonal ligand: 4′-(4-pyridyl)-3,2′:6′,3″-terpyridine

Two novel Zn(II) coordination polymers, [Zn₅(pytpy)₈(fum)₄(H₂O)₄(OH)₂]_n · n(CH₃OH) · 2n(H₂O) (1) and [Zn₃(pytpy)₄ (btc)₂]_n · 2n(H₂O) (2) (pytpy = 4′-(4-pyridyl)-3,2′:6′,3″-terpyridine, H₂fum = fumaric acid, H₃btc = 1,3,5-benzenetricarboxylic acid) have been hydrothermally synthesized and structurally characterized. Complex 1 is a 2D layer structure, which is constructed from linear pentanuclear Zn(II) subunits interconnected via bidentate-bridging pytpy ligands and tridentate-bridging fum²⁻ anions. Complex 2 is a 3D network structure, μ₂-pytpy ligands link the layers based on the heart-like hexanuclear subunits to form the 3D network. Both complexes show strong fluorescence emission upon excitation at 310 nm in solid state. Additionally, these two complexes possess great thermal stabilities, especially for 2, the framework is stable up to 350 °C.     

Synthesis and structural characterization of an alternating double aquo-bridged and single cyano-bridged polymeric barium–iron complex: {[Ba2(phen)4(H2O)6Fe(CN)6]·Cl·2(phen)·3H2O}n

A new alternating double aquo-bridged and single cyano-bridged polymeric complex {[Ba₂(phen)₄(H₂O)₆Fe(CN)₆]·Cl·2(phen)·3H₂O}_n (1) (phen = 1,10-phenanthroline) has been synthesized and structurally characterized. In the crystal structure the two centrosymmetric [Ba₂(phen)₄(H₂O)₆] units are bridged through two trans CN groups of [Fe(CN)₆]³⁻ ion, which results in the formation of a zig-zag polymeric chain. In each [Ba₂(phen)₄(H₂O)₆] unit, the two Ba centers are joined by double aquo bridges. Both the Ba atoms are 9-coordinated with distorted mono-capped square antiprismatic geometry. An elaborate hydrogen bonding system holds the parallel polymeric chains together.     

pH Dependent formations of dinuclear molybdenum(V) and incomplete cubane molybdenum(IV) complexes with nitrilotriacetate

Nitrilotriacetato oxomolybdenum(V) dinuclear complex (NH₄)₄[cis-Mo₂O₄(nta)₂] · 7H₂O (1) (H₃nta = nitrilotriacetic acid) and its incomplete cubane-type trinuclear molybdenum(IV) complex [Mo₃O(OH)₃(Hnta)₃] · Cl · 3H₂O (2) are isolated in a weak acidic and an acidic solutions, respectively (pH 4.5 and 1.0). The nitrilotriacetate ligand in the anion 1 or the cation 2 displays tridentate mode through the nitrogen atom and the oxygen atoms of β-carboxy groups. Unusual protonations of bridged oxygen atoms in 2 have not effect on the skeleton of molybdenum(IV) cap Mo₃O unit. There are obvious dissociations of molybdenum(V) complexes based on ¹³C NMR observations in solution.     

Syntheses, structures, and photoluminescence of two Cd(II) coordination polymers constructed from analogue (pyridyl)imidazole derivative and polycarboxylate acid

Two novel Cd(II) coordination frameworks based on a semirigid asymmetric ligand L and aromatic multi-carboxylate ligands, {[Cd₂L(btc)(H₂O)₂]·5H₂O}_n (1) and [Cd₂L₂(bdc)]_n (2) (L = (4-((2-(pyridine-2-yl)-1H-imidazol-1-yl)methyl)benzoic acid, H₃btc = 1,3,5-benzenetricarboxylic acid, H₂bdc = 1,3-benzenedicarboxylic acid), have been hydrothermally synthesized, and structurally characterized by elemental analysis, IR spectroscopy, single-crystal X-ray crystallography. Due to various coordination modes and conformations of the semirigid asymmetric ligand, and carboxylate containing co-ligands, therefore, the two complexes exhibit structural and dimensional diversity. Complex 1 exhibits a novel 2D (3, 5)-connected network structure with (3·5²)(3²·5³·6⁴·7) topology. Complex 2 exhibits a novel 3D CdSO₄ topology, which is formed from different dinuclear cadmium units. In addition, the photoluminescence properties of the free ligand L, and complexes 1 and 2 were studied in the solid state at room temperature.     

3-D supramolecular frameworks assembled by lanthanide binuclear molecules based on 1,2-phenylenedioxydiacetic acid and 1,10-phenanthroline

The complexes [Ln₂(PDOA)₃(phen)₂(H₂O)₂] · 2H₂O (Ln = Eu (1), Tb (2), and Dy (3); H₂PDOA = 1,2-phenylenedioxydiacetic acid; phen = 1,10-phenanthroline) have been synthesized and structurally characterized by single crystal X-ray diffraction methods. The three complexes are all binuclear molecules. The two Ln(III) centers are linked by only one PDOA ligand through its two bidentate-chelating carboxylate groups. PDOA also acts as a terminal ligand using one carboxylate oxygen and ether oxygen atoms to chelate the Ln(III) ion. 3-D supramolecular frameworks are built up by the hydrogen bonds and π–π stacking interactions. The fluorescent spectra of the three complexes show the characteristic emission of the Eu(III) for 1, Tb(III) for 2, and Dy(III) for 3, respectively.     

Temperature-controlled structural diversity of two Cd(II) coordination polymers based on a flexible tripodal multicarboxylate ligand

Two new 3-D Cd(II) coordination polymers (CPs) with 3,5-bi(4-carboxyphenoxy)-benzoic acid (H₃L), namely [Cd₃(L)₂(H₂O)₄]·4H₂O (1) and [Cd₃(L)₂(H₂O)₃]·2H₂O (2), were successfully synthesized under hydrothermal condition at 140 °C and 180 °C, respectively. Complex 1 is constructed from 1-D (–Cd–O–)_∞ rod-shaped SBUs (secondary building units) and ‘Y’-shaped L ligands. In complex 2, the 3-D network is mediated by 2-D [Cd(COO)₂]_n layered motifs and ‘T’ and ‘Y’-shaped L ligands. The results show that the reaction temperature plays a key role on the final structures of the complexes. The luminescent properties of the complexes have also been investigated.     

Two new 3-D coordination polymers with 5-tert-butyl isophthalic acid and flexible N-donor co-ligands bearing linear trinuclear secondary building blocks

Two new 3-D coordination polymers bearing linear trinuclear secondary building blocks with mixed bridging ligands, {[Ni₃(tbip)₂(Htbip)₂(bib)₂]·4H₂O}_n (1) and {[Co₃(tbip)₂(Htbip)₂(btb)₂]·4H₂O}_n (2) (H₂tbip = 5-tert-butyl isophthalic acid, bib = 1,4-bis(imidazol-1-yl)butane, btb = 1,4-bis(1,2,4-triazol-1-yl)butane), were obtained and characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis, single-crystal X-ray crystallography and powder X-ray diffraction. Both complexes 1 and 2 display similar 3D 6-connected pcu networks containing the linear trinuclear [M₃(COO)₆] (M = Ni and Co) clusters as nodes.     

Structure and magnetic properties of a copper malonate/dipyridylamine layered coordination polymer with both syn–anti and anti–anti copper carboxylate chains

The novel 2-D copper metal–organic layered coordination polymer {[Cu₂(malonate)₂(dpa)(H₂O)₂] · H₂O} (1, dpa = 4,4′-dipyridylamine) has been prepared and characterized by single-crystal X-ray diffraction, IR and thermogravimetric analysis. The structure of compound 1 consists of alternating syn–anti and anti–anti copper malonate 1-D chains linked into a (6,3) herringbone layer motif through tethering dpa ligands. Variable temperature magnetic studies indicate weak ferromagnetic coupling through the 1-D copper malonate chains with J = 0.64(1) cm⁻¹ and g = 2.033(4).     

Two 2-D 4-connected lanthanide coordination framework based on benzimidazole-5,6-dicarboxylate and acetate mixed ligands

Two 2-D polymers, [Ln(bidc)(Ac)·H₂O]_n (Ln = Tb(1), Dy(2) H₂bidc = benzimidazole-5,6-dicarboxylic acid, HAc = acetic acid), have been successfully synthesized under hydrothermal conditions at 150 °C and characterized by elemental analysis, infrared spectra and single-crystal X-ray diffraction. Single crystal X-ray diffraction analyses reveal that the two compounds are isomorphous and exhibit one new (4,4)-connected 2-nodal (4⁴·6²)(4⁴·6²) layer-like net, stabilized by the interchain hydrogen bonding N–H?O, O–H?O and π?π stacking interactions between two benzimidazole rings. 2-D layers are further connected by the interlayer O–H?O hydrogen-bonding interactions to form a 3-D supermoleculaer network. Moreover, the luminescent property of compound 1 and thermogravimetric analyses of the two complexes 1–2 are discussed in detail.     

A new 3D supramolecular compound containing 1D chains and 1D water chains

The first crystal structure involving the discrete unsubstituted 1,2,4-triazolate anion is reported. In the title compound, [Na₂(H₂O)₈]_n(trz)_2n [trz = 1,2,4-triazolate] (1), each sodium(I) ion is coordinated by six water molecules with a slight distorted octahedron geometry. Each Na(I) are bridged by two μ₂-aqua ligands and arranged in an alternating fashion to construct a 1D zigzag {[Na₂(H₂O)₈]²⁺}_n chain. The 3D supermolecular framework is formed with 1D {[Na₂(H₂O)₈]²⁺}_n chain as the assembly units, by 1D water chain and 1,2,4-triazolate anion as the hydrogen bonding spacers.     

Novel ether-containing ligands as potential technetium(I) heart agents

A novel pair of lipophilic cationic technetium complexes utilizing the ^99mTc-tricarbonyl core have been developed and evaluated for cardiac uptake. Di-(pyridyl-2-methyl)amine (DPA) and di-(imidazol-2-ylmethyl)amine (DIA) ligands were functionalized using aliphatic or aromatic ether substituents to provide the ligands 3 and 4. Octahedral complexes with the fac {^99mTc(CO)₃(ligand)}⁺ configuration were readily formed by reaction of ^99m[Tc(CO)₃(H₂O)₃]⁺ with the ether-containing tridentate ligands. The ^99mTc-tricarbonyl complexes, formed in >90% RCY and >90% RCP, were stable to transchelation in vitro against molar excesses of cysteine and histidine. Preliminary evaluation in rats after intravenous administration showed that the complexes concentrated in the heart muscle to an extent greater than surrounding tissue and blood. The ^99mTc-complex with derivatized DIA, {^99mTc(CO)₃(4)}⁺ (8), demonstrated 1.8% ID/g in the heart and a 90:1 heart to blood ratio at 120 min post-injection. These initial results provide support for an expanded evaluation of novel cationic ^99mTc-complexes for cardiac imaging.     

Diverse architectures of hybrid materials induced by different mixed-ligands and applications in luminescence

For investigating the effects of different azacyclo-assisting ligands and O-donor bridging ligands on the structural construction, three different structural complexes, namely, {Zn(DBTA)(phen)(H₂O)}_n (1) (DBTA = 2, 5-Dibromo-terephthalic acid, phen = 1,10-Phenanthroline), [Zn(DBTA)(bimb)]_n (2) (bimb (1,4-bis(imidazole-1-ylmethyl)benzene) and {[Zn₂(bmimb)(PO₄)₂]·(H₂O)₂}_n (3) (bmimb = 1,2-bis(methylimidazole-1-ylmethyl) benzene) have been constructed by different mixed-ligands and Zn atoms. Their structures have been characterized by single-crystal X-ray diffraction analysis, elemental analysis, and Infrared spectroscopy. Complex 1 exhibits a common 2D layer with 4,4-connected topology. Complex 2 features an interesting 2-fold interpenetrating net with the aid of long-chain flexible azacyclo-assisting ligands. Complex 3 shows 3D supramolecular architecture with tetranuclear water cluster filling in the pores. Their fluorescence properties were also measured.     

Synthesis,structure and magnetic property of the first 2-D organic–inorganic hybrid sandwich-type polyoxotungstate containing O-donor organic ligands

An unprecedented 2-D organic–inorganic hybrid sandwich-type polyoxotungstate containing O-donor organic ligands [DMAH]₄{[Mn(DMF)₄]₂[Mn₄(DMF)₂(α-B-HPW₉O₃₄)₂]} (1) (DMA = dimethylamine, DMF = N,N-dimethylformamide) has been solvothermally synthesized and characterized by IR, UV spectra and X-ray single-crystal diffraction. The 2-D organic–inorganic hybrid network of 1 is built by tetra-Mn^II substituted sandwich-type polyoxotungstates [Mn₄(DMF)₂(α-B-HPW₉O₃₄)₂]^8? and [Mn(DMF)₄]²⁺ cation bridges, which displays the common 2-D (4,4) topological net. It should be noted that the major difference between [Mn₄(DMF)₂(α-B-HPW₉O₃₄)₂]^8? in 1 and the reported [Mn₄(H₂O)₂(α-B-PW₉O₃₄)₂]^10? is that two DMF ligands substitute two H₂O ligands on the Mn₄O₁₆ unit located in the sandwich belt. Magnetic susceptibility measurement indicates the occurrence of antiferromagnetic coupling interaction within Mn^II ions.     

One 2D anionic coordination polymer with {[Co(H2O)6]}2 + cationic guest for fast and selective adsorption of cationic dyes

One new anionic Coordination Polymer, namely [Co(H₂O)₆]^2 +·[Co₃(bptc)₂(H₂O)₁₀]^2 −·3H₂O (1), where H₄bptc = 3,3′,5,5′-biphenyltetracarboxylate, has been synthesized hydrothermally and characterized. In compound 1, bptc^4 − as tridentate ligands connect the Co^2 + cations to form a 2D layer with 1D pseudo channels encapsulation of [Co(H₂O)₆]^2 + guest. In addition, their adsorption activities for organic dyes were investigated in aqueous solution. The results suggested that the anionic complex 1 show rapid and selective adsorption of cationic dyes for Neutral red, Methylene blue.     

Metal-organic frameworks constructed from monomeric,dimeric and trimeric phenanthroline citrate zinc building units

Adduct of mononuclear and dinuclear citrate zinc complex [Zn(Hcit)(phen)(H₂O)][Zn₂(Hcit)(phen)₂(H₂O)₃]·13.5H₂O (1) and its aggregate [Zn₃(Hcit)₂(phen)₄]_n·14nH₂O (2) (H₄cit = citric acid, phen = 1,10-phenanthroline) were synthesized in weak acidic solutions. The former was obtained from the reaction of zinc nitrate, citric acid and phenanthroline in a molar ratio of 3:2:3, while a slightly excess of phenanthroline results in the formation of the polymeric product 2 in a molar ratio of 3:2:4. Transformation of 1 to 2 was finished by the reaction of 1 with an equimolar of phenanthroline in 72% yield. Reverse conversion of 2 to 1 is obtained in 77% yield, showing an equilibrium between 1 and 2. Neutral compound 1 consists of one monomeric anionic unit [Zn(Hcit)(phen)(H₂O)]^? and one dimeric cationic unit [Zn₂(Hcit)(phen)₂(H₂O)₃]⁺ that connect each other by strong hydrogen bonds [O6?O4w 2.636(2); O7?O3w 2.630(3) Å]. In 2, the citrate ligand links each trinuclear unit [Zn₃(Hcit)₂(phen)₄] to generate an infinite 1D chain that extents into a 3D supramolecular structure by intra- and inter-molecular hydrogen bonds. Moreover, 1 and 2 exhibit strong fluorescence at room temperature.