A metal-organic framework with rich accessible nitrogen sites for rapid dye adsorption and highly efficient dehydrogenation of formic acid.

MOFs with adequate free nitrogen sites have potential applications in dye adsorption and formic acid dehydrogenation. Here, we successfully synthesized a novel 3-D MOF 1 ([(CH3)2NH2][Cd(L)DMA]·0.5DMA·1.5H2O) with a special two-fold interpenetrating framework through a simple solvothermal reaction between CdCl2·1.5H2O and a nitrogen-rich triangular tricarboxylate-based linker (H3L, 4,4',4''-s-triazine-2,4,6-tribenzoic acid). After removing the guest molecules of dimethylacetamide (DMA) and H2O, including the coordinated DMA from 1 by vacuum activation at 423 K, a compound named 1' with a formula of [(CH3)2NH2][Cd(L)] and a similar interpenetrating framework structure was obtained. In comparison with compound 1, the total void volume of 1' is nearly doubled, and thus may provide higher potential for the adsorption of other guest molecules. Notably, the pyridine N atoms located in the middle of the triangular tricarboxylate-based linker are not involved in the coordination with Cd2+, and are all uniformly dispersed throughout the whole framework of the 3-D MOFs. Due to its unique structural features, the 3-D MOF 1' could effectively adsorb the cationic dye MB+ for recycling purposes. The rapid adsorption rate (0.7 × 10-2 g mg-1 min-1) and the relatively high capacity (900 mg g-1) for MB+ demonstrate the potential of 1' in dye adsorption. In addition, 1' may also be used as an effective support to immobilize PdAu NPs via the double-solvent method. The resultant catalyst Pd0.8Au0.2/1' exhibits decent catalytic activity for the dehydrogenation of formic acid with a TOF value of 1854 h-1 at 333 K. The existence of a large void volume and accessible pyridine N atoms provide a suitable environment for achieving a high dispersion of PdAu NPs, thereby leading to the formation of a catalytically active and stable supported noble-metal NP catalyst for H2 generation from formic acid decomposition.

Porous 3,4-di(3,5-dicarboxyphenyl)phthalate-based Cd2+ coordination polymer and its potential applications.

Porous coordination polymers with organic aminium as one of the guest species possess a potential application in dye adsorption and white-light material manufacture. Polycarboxylic acid with multiple COOH substituents tends to form this type of porous material (with metal ion). Here the solvothermal self-assembly between Cd2+ and a hexacarboxylic acid creates such a porous material [(CH3)2NH2]6[Cd3(L)2]·5DMF·3H2O (H6L = 3,4-di(3,5-dicarboxyphenyl)phthalic acid) 1. Total potential guest accessible void volume in 3-D 1 is found to be 4327 Å3. Based on its better porous structure and stability, the ability of 1 to adsorb organic dyes is investigated. It has been proved that (i) 1 can selectively adsorb cationic dyes as Azure A (AA+) and/or Methylene Blue (MB+), rather than neutral and anionic ones; (ii) the maximum adsorption capacity is 698.2 mg·g-1 for AA+ and 573.2 mg·g-1 for MB+, respectively; and (iii) to the adsorption of AA+, it can be recycled for at least five rounds. Also, it is utilized to fabricate the while-light emitting material. Based on the blue-light emission of 1, the trace Eu3+ and Tb3+ ions are introduced into the pores of 1 successfully, obtaining a white-light emitting material Eu3+/Tb3+@1 (CIE chromaticity coordinates: (0.33, 0.32)). Meanwhile, Eu3+/Tb3+@1 is found to be a potential fluorescence photochromic material, showing a yellow-white-blue light emission. According to these investigations, the relationship between material structure and its adsorption property for dyes, the points that should be paid attention to in the construction of white-light emitting materials as well as the potential adsorption mechanism for dyes and rare earth ions are deeply discussed.

Bisimidazole-based phosphorescent thiocyanatocadmates.

Simple room-temperature self-assemblies between Cd2+ salts, SCN- and bisimidazole molecules at pH = 2 created three new organically templated thiocyanatocadmates [H2(L1)][Cd(SCN)4]·H2O (L1 = 1,4-bis(1H-imidazol-1-yl)benzene) 1, [H2(L2)][Cd(SCN)4] (L2 = 1,3-bis(2-methylimidazol-1-yl)propane) 2, and [H2(L3)][Cd2(SCN)6] (L3 = 1,4-bis(2-methyl-1H-imidazol-1-yl)butane) 3. X-ray single-crystal diffraction analysis reveals that (i) in 1-3, the SCN- groups doubly bridge the Cd2+ centers to form different thiocyanatocadmates: a linear chain in 1; a zigzag chain in 2; and a 2-D layer network (63 net) in 3; and (ii) in 1, via Nbase-HNSCN interactions, the L1 molecules extend the thiocyanatocadmate chains into a 2-D supramolecular layer, whereas in 2, the zigzag thiocyanatocadmate chains self-assemble into a 3-D supramolecular network via weak SS interactions. Photoluminescence analysis indicates that the three title compounds all emit light: blue light for 1 and 2 and green light for 3. At low temperatures, the emission positions of the three compounds hardly change, but the emission intensities are largely enhanced. Interestingly, after turning off the UV lamp, 1 and 2 still briefly emit light (ca. 2 s), which means that 1 and 2 possess phosphorescence properties. Phosphorescence lifetimes at 77 K are 1619 ms for 1 and 247 ms for 2.

Copper(i)-polymers and their photoluminescence thermochromism properties.

Under hydro(solvo)thermal conditions, four organic bidentate bridging N,N'-donor ligands 1,3-bis(2-methylimidazol-1-yl)propane (L1), 4,4'-di(1H-imidazol-1-yl)-1,1'-biphenyl (L2), 1,2-bis(2-methyl-1H-imidazol-1-ylmethyl)benzene (L3) and 5,6,7,8-tetrahydroquinoxaline (L4) were employed to react with CuBr/CuI, generating four 2-D layered copper(i)-polymer coordination polymer materials [Cu2Br2(L1)] 1, [CuI(L2)] 2, [CuI(L3)] 3 and [CuI(L4)0.5] 4. In 1-4, different Cu-X motifs are found: a cubic Cu4Br4 core in 1; a castellated Cu-I single chain in 2; a rhombic Cu2I2 core in 3; and a staircase-like Cu-I double chain in 4. The 2-D layer networks of 1-3 can all be simplified into a simple 44 topology (planar for 1 and 3; wave-like for 2), while the 2-D layer network of 4 has a 63 topology. The photoluminescence behaviors of 1-4 under a UV lamp suggest that 1 and 2 possess fluorescence thermochromism properties. Under the UV lamp, with the decrease in temperature, (i) 1 exhibits a yellow-to-red emission; (ii) 2 exhibits a yellow-to-green emission; (iii) 3 always emits green light; and (iv) 4 never emits light. These are further confirmed by their emission spectra. From 297 K to 77 K, the emission of 1 exhibits a large red shift from 561 nm to 623 nm; the emission of 2 exhibits a large blue shift from 571 nm to 515 nm; only a minor red shift is observed for the emission of 3; and no peaks appear in the emission spectra of 4. The crystal data of 1 and 2 at different temperatures have been collected for revealing the origination of their fluorescence thermochromism properties. Based on the above investigations, the effect of the rigidity/flexibility of the organic ligand on the fluorescence thermochromism properties of copper(i)-polymer coordination polymer materials is discussed. The quantum yields at 297 K and the photoluminescence lifetimes at 297 K and 77 K for 1-3 were also measured for better understanding their photoluminescence properties.

A Series of Compounds Based on [P2W18O62]6- and Transition Metal Mixed Organic Ligand Complexes with High Catalytic Properties for Styrene Epoxidation.

Seven compounds based on [P2W18O62]6- ({P2W18}) were successfully prepared and carefully characterized. [HC5H5N][Cu(2,2'-bpy)2]2[HP2W18O62]·2H2O (bpy = bipyridine) (1) is constructed from {P2W18} bridged by [Cu(2,2'-bpy)2]2+. [HC5H5N][Zn(2,2'-bpy)2]2[HP2W18O62]·4H2O (1a) is isostructural and isomorphous with compound 1. [Cu4(2,2'-bpy)3(nic)3(OH)2(H2O)][H3P2W18O62]·0.5H2O (nic = nicotinic acid) (2) is formed by {P2W18} and tetracopper transition metal mixed organic ligand complexes (TMMCs). [Cu2(2,2'-bpy)2(C2O4)]3[P2W18O62]·3H2O (3) is made up of {P2W18} and bicopper TMMCs, [Cu6(2,2'-bpy)6(OH)6][P2W18O62]·2H2O (4) is built up from {P2W18}, and hexacopper complexes of 2,2'-bpy and hydroxyls. [Cu(2,2'-bpy)(hnic)0.5][Cu3(2,2'-bpy)3(hnic)2(H2O)2][H3P2W18O62] (hnic = hydroxyl nicotinic acid) (5a) contains two different TMMCs. In addition, compound 5a is the first example of a compound that contains Cu-π interactions. [Cu2(2,2'-bpy)2(hnic)][H4P2W18O62]· xH2O ( x ≈ 50) (5b) is based on {P2W18} and [Cu2(2,2'-bpy)2(hnic)]2+. We discuss the mechanisms for the formations of these compounds. All the catalytic performances of the compounds for styrene epoxidation to styrene oxide are high.

New photoluminescent iodoargentates with bisimidazole derivatives as countercations.

In this article, three bisimidazole derivatives (1,4-bis(2-ethylimidazol-1-yl)butane, L1; 4,4'-di(1H-imidazol-1-yl)-1,1'-biphenyl, L2'; and 1,3-bis(2-ethylimidazol-1-yl)propane, L3) were employed to solvothermally react with AgI in an acidic environment, creating three new 1-D chained iodoargentates [H(L1)][Ag5I6]·DMF (DMF = N,N'-dimethylformamide) 1, [L2][Ag3I5] (L22+ = 4,4'-di(1H-imidazol-1-ium)-1,1'-biphenyl) 2, and [H2(L3)][Ag2I4] 3. L22+ in 2 originated from the in situ N-alkylation of L2' with the CH3OH solvent. X-ray single-crystal diffraction analysis reveals that (i) in 1, Ag+ and I- aggregate to form a 1-D tube-like iodoargentate, which exhibits the same topology as the carbon tube; (ii) the chain structure of the iodoargentate in 2 is based on a kind of trinuclear Ag-I cluster, which can be viewed as a segment of the classical cubic M4I4 cluster; (iii) the chain structure of the iodoargentate in 3 is simple, which can be described as a linear arrangement of the AgI4 tetrahedra by sharing edges. The photoluminescence analysis reveals that at 77 K, (i) 1 and 2 emit strong yellow light with ms-grade photoluminescence lifetimes (5.460 ms for 1, 6.931 ms for 2); (ii) 3 possesses photochromic luminescence properties. Upon excitation at 254 nm, it emits blue-green light, whereas upon excitation at 365 nm, it emits yellow light.

A series of organic-inorganic hybrid compounds formed by [P2W18O62]6- and several types of transition metal complexes.

Five new organic-inorganic hybrid compounds based on [P2W18O62]6- (abbreviated as {P2W18}) and several types of transition metal complexes (TMCs) have been synthesized and characterized by IR, UV-Vis, XRD, cyclic voltammetry measurements and single crystal X-ray diffraction analysis. [Cu(phen)2][Cu(phen)(H2O)3][Cu(phen)2(H2O)][P2W18O62]·8H2O (1) (phen = 1,10-phenanthroline) is a {P2W18} bi-supported complex of phen, while [Cu(2,2'-bpy)(H2O)2]2[Cu(2,2'-bpy)2][P2W18O62]·3.5H2O (2) (2,2'-bpy = 2,2'-bipyridine) is a 1-D chain structure formed by {P2W18} and copper complexes of 2,2'-bpy. [Ag(2,2'-bpy)2]5[HP2W18O62]·H2O (3), [Ag(2,2'-bpy)(H2O)]2[Ag(2,2'-bpy)]2[Ag2(2,2'-bpy)3][P2W18O62] (4), and [Ag(2,2'-bpy)(H2O)]3[Ag2(2,2'-bpy)3][Ag(2,2'-bpy)][P2W18O62]·H2O (5) are constructed from {P2W18} and silver complexes of 2,2'-bpy. Compounds 4 and 5 are novel dimers of {P2W18} joined by silver complexes, while compound 3 contains two different kinds of silver complexes, forming a novel supramolecular structure. Each of the five compounds is formed by {P2W18} and more than one type of TMC. The formation mechanism of these compounds has been carefully discussed. In addition, we also synthesized two supramolecular structures based on {P2W18} and organic moieties: [H6P2W18O62](phen)5.5 (6) and [H6P2W18O62](phen)3·43H2O (7). The catalytic properties of these compounds were also tested.

New in situ generated acylhydrazidate-coordinated complexes and acylhydrazide molecules: Synthesis, structural characterization and photoluminescence property.

By utilizing the hydrothermal in situ acylation of organic acids with N2H4, three acylhydrazidate-coordinated compounds [Mn(L1)2(H2O)2] (L1=2,3-quinolinedicarboxylhydrazidate; HL1=2,3-dihydropyridazino[4,5-b] quinoline-1,4-dione) 1, [Mn2(ox)(L2)2(H2O)6]·2H2O (L2=benzimidazolate-5,6-dicarboxylhydrazide; HL2=6,7-dihydro-1H-imidazo[4,5-g]phthalazine-5,8-dione; ox=oxalate) 2, and [Cd(HL3)(bpy)] (L3=4,5-di(3'-carboxylphenyl)phthalhydrazidate; H3L3=6,7-dihydro-1H-imidazo[4,5-g]phthalazine-5,8-dione; bpy=2,2'-bipyridine) 3, as well as two acylhydrazide molecules L4 (L4=oxepino[2,3,4-de:7,6,5-d'e']diphthalazine-4,10(5H,9H)-dione) 4 and L5 (L5=4,5-dibromophthalhydrazide; L5=6,7-dibromo-2,3-dihydrophthalazine-1,4-dione) 5 were obtained. X-ray single-crystal diffraction analysis reveals that (i) 1 only possesses a mononuclear structure, but it self-assembles into a 2-D supramolecular network via the NhydrazineH⋯Nhydrazine and OwH⋯Ohydroxylimino interactions; (ii) 2 exhibits a dinuclear structure. Ox acts as the linker, while L2 just serves as a terminal ligand; (iii) In 3, L3 acts as a 3-connected node to propagate the 7-coordinated Cd(2+) centers into a 1-D double-chain structure; (iv) 4 is a special acylhydrazide molecule. Two OH groups for the intermediates 3,3'-biphthalhydrazide further lose one water molecule to form 4; (v) 5 is a common monoacylhydrazide molecule. Via the NhydrazineH⋯Ohydrazine, OhydroxyliminoH⋯Oacylamino and the π⋯π interactions, it self-assembles into a 2-D supramolecular network. The photoluminescence analysis reveals that 4 emits light with the maxima at 510nm.

A new three-dimensional Zn(2+) coordination polymer constructed from oxalate and 1,2,4-triazolate.

A new 3-D Zn(2+) coordination polymer (CP) [(CH3)2NH2]3[Zn6(ox)4.5(trz)6]⋅4H2O (ox=oxalate; trz=1,2,4-triazolate) 1 was obtained by a simple solvothermal self-assembly. The crystal structural analysis demonstrates that the trz molecules link the Zn(2+) ions into a two-dimensional (2-D) layer network, which is based on the trinuclear Zn3(trz)6 clusters. The ox molecules serve as the linkers to propagate the 2-D layers into a three-dimensional (3-D) network of 1. The thermogravimetry (TG) behavior, photoluminescence property, and the sensing ability of 1 are investigated. The sensing experiment on nitrobenzene (NB) reveals that 1 can serve as a fluorescence probe to detect NB at the ppm concentration.

New organic-inorganic hybrid compounds constructed from polyoxometalates and transition metal mixed-organic-ligand complexes.

Five new organic-inorganic hybrid compounds based on different polyoxoanions [HxGeW12O40](n-) or [H3As2W18O62](3-) (x = 0, 2; n = 4, 2), namely [Cu3(2,2'-bpy)3(inic)(OH)(H2O)][GeW12O40]·1.5H2O (1), [Cu2(phen)2(µ2-Cl)2(inic)]2[H2GeW12O40]·2H2O (2), [Cu2(phen)2(µ2-Cl)Cl(nic)]2[H2GeW12O40] (3), [Cu2(2,2'-bpy)2(hnic)Cl]2[H2GeW12O40] (4), [Cu(phen)(inic)H2O][Cu2(phen)2(inic)2(H2O)][H3As2W18O62]·3H2O (5) (inic = isonicotinic acid, nic = nicotinic acid, hnic = 2-hydroxy-nicotinic acid, 2,2'-bpy = 2,2'-bipyridine, phen = 1,10-phenanthroline), have been synthesized and characterized by IR, UV-Vis, XRD, cyclic voltammetric measurements and single crystal X-ray diffraction analysis. Single crystal X-ray analysis reveals that compound 1 is isomorphous and isostructural with a compound reported by us recently, the main difference between the two is the heteroatom of the polyoxoanions in the two compounds. Compound 2 is a supramolecular structure constructed from polyoxoanions and transition metal mixed-organic-ligand complexes. Compound 3 is a novel polyoxoanion bi-supported transition metal mixed-organic-ligand complex. Compound 4 is a 1-D chain structure constructed from polyoxoanions and transition metal mixed-organic-ligand complexes. The photodegradation properties of compounds 1-5 have been analyzed.

Tuning the structures based on polyoxometalates from 1-D to 2-D by using different secondary organic ligands.

Six new organic-inorganic hybrid compounds based on [XM12O40](4-) (X = heteroatom, M = metal atom), namely [Cu(pic)2][H2XM12O40]·2Hapy·2apy (X = Si, M = W for , X = Ge, M = W for and X = Si, M = Mo for ), [Cu(2,2'-bpy)2][Cu(2,2'-bpy)(H2O)][Cu(pic)2]0.5[XM12O40]·nH2O (X = Si, M = Mo, n = 0.5 for , X = Ge, M = W, n = 1 for ) and [Cu(phen)(H2O)]2[Cu(pic)2][GeW12O40]·2.5H2O () (pic = deprotonated picolinic acid, apy = 2-aminopyridine, 2,2'-bpy = 2,2'-bipyridine, phen = phenanthroline), have been synthesized and characterized by IR, UV-Vis, XRD, cyclic voltammetric measurements and single crystal X-ray diffraction analysis. Single crystal X-ray analysis reveals that compounds are isomorphous and isostructural, in which each is based on [H2XM12O40](2-) and [Cu(pic)2]. Compounds and are also isomorphous and isostructural, of which the structures are more interesting than those of compounds . Both structures are constructed from [XM12O40](4-) and metal mixed-organic-ligand complexes. Compound is also constructed from Keggin ions and metal mixed-organic-ligand complexes, which are, however, thoroughly different from those of compounds and . The photodegradation properties of compounds have been analyzed. Compounds also exhibit rapid absorption properties for RhB (Rhodamine B). Detailed analysis of the photodegradation properties of compounds reveals that the molybdate POM has stronger degradation ability for RhB than the tungstate one.

New organically templated thiocyanatocadmates and chlorocuprate(II): synthesis and structural characterization.

With various organic base molecules as the countercations, five new thiocyanatocadmates [H2(tmen)][Cd(SCN)4] (tmen = N,N,N',N'-tetramethylethylenediamine) 1, [H2(tmba)][Cd2(SCN)6] (tmba = N,N,N',N'-tetramethyl-1,4-butanediamine) 2, [H2(teen)][Cd2(SCN)6] (teen = N,N,N',N'-tetra-ethylethylenediamine) 3, [H(amp)][Cd(SCN)2(CH3COO)] (amp = 2-amino-6-methylpyridine) 4 and [H(abp)]4[Cd(SCN)4]SO4·H2O (abp = 2-amino-6-bromopyridine) 5, and one new chlorocuprate(II) [H2(cha)][CuCl4] (cha = 1,4-cyclohexanediamine) 6 were obtained from a series of simple room-temperature self-assemblies at pH = 2 or 6.5. X-ray single-crystal diffraction analysis reveals that (i) templated by [(CH3)2NH(CH2)2NH(CH3)2](2+) (H2(tmen)(2+)), the anion [Cd(SCN)4](2-) in 1 shows a 1-D linear single-chain structure, whereas templated by [(CH3)2NH(CH2)4NH(CH3)2](2+) (H2(tmba)(2+)), the anion [Cd2(SCN)6](2-) in 2 shows a 1-D linear double-chain structure. The number of C atoms between the two N atoms in the templating agent controls the width of the anionic chain through the N(amino)-H···N(SCN) interactions; (ii) templated by [(C2H5)2NH(CH2)2NH(C2H5)2](2+) (H2(teen)(2+)), the anion [Cd2(SCN)6](2-) in 3 exhibits a 3-D open-framework structure, which is based on zigzag anionic chains. A direct change of the substituent group from -CH3 to -C2H5 alters indirectly the shape of the anionic chain from a linear shape to a zigzag shape; (iii) 4 shows a 3-D supramolecular network structure, which is built up from the 1-D zigzag anionic structures by the H(amp)(+) molecules via N-H···O interactions. The formation of the zigzag chain derives from the chelation of the CH3COO(-) groups to the Cd(2+) centers; (iv) 5 is indeed a double salt of [H(abp)]2[Cd(SCN)4] and [H(abp)]2SO4. SO4(2-) and H(abp)(+) form a supramolecular aggregation. Surrounded by the aggregations, the anion [Cd(SCN)4](2-) only shows a dinuclear structure; and (v) templated by H2(cha)(2+), the anion [CuCl4](2-) in 6 displays a 2-D perovskite layer structure. The photoluminescence analysis indicates that upon excitation (λ(ex) = 335 nm for 4, λ(ex) = 395 nm for 5), and emit light (λ(em) = 365 nm for 4, λ(em) = 470 nm for 5), which can be seen clearly under the UV lamp.

Polyoxometalate-based organic-inorganic hybrid compounds containing transition metal mixed-organic-ligand complexes of N-containing and pyridinecarboxylate ligands.

Five new organic­inorganic hybrid compounds based on the Keggin-type polyoxoanion [SiW12O40]4−, namely [Cu3(2,2'-bpy)3(inic)(µ2-OH)(H2O)][SiW12O40]·2H2O (1), [Cu6(phen)6(µ3-Cl)2(µ2-Cl)2Cl2(inic)2][SiW12O40]·6H2O (2), [Cu2(hnic)(2,2'-bpy)2Cl]2[H2SiW12O40] (3), [Cu2(nic)(phen)2Cl2]2[SiW12O40] (4) and [Cu2(pic)(2,2'-bpy)2Cl]2[SiW12O40] (5) (inic = isonicotinic acid, hnic = 2-hydroxy-nicotinic acid, nic = nicotinic acid, pic = picolinic acid, 2,2'-bpy = 2,2'-bipyridine, phen = 1,10-phenanthroline) have been synthesized and characterized by IR, UV-Vis, XPS, XRD, cyclic voltammetric measurements, photoluminescence analysis and single crystal X-ray diffraction analysis. Crystal analysis reveals that compound 1 exhibits a 2-D double layered framework structure constructed from [SiW12O40]4− and copper-aqua-2,2'-bipy-hydroxyl-isonicotinate complexes. Compound 2 is a 0-D discrete structure formed by [SiW12O40]4− and copper-chloro-isonicotinate-phenanthroline complexes. Compound 3 shows a 1-D single chain structure based on the linkage of copper-2,2-bpy-chloro-2-hydroxy-nicotinate complexes and [SiW12O40]4−. Compounds 4 and 5 both contain polyoxometalate supported transition metal complexes, one is a polyoxometalate supported copper-chloro-nicotinate-phenanthroline complex in 4, and the other is a polyoxometalate supported copper-2,2-bpy-chloro-nicotinate complex in 5. It should be noted that nicotinic, isonicotinic and picolinic acids are structural isomers and 2-hydroxy-nicotinic acid is an in situ hydroxylated product of nicotinic acid. In addition, photocatalytic degradation of Rhodamine B (RhB) by compounds 1­5 has been investigated in aqueous solutions.

New 1-D and 3-D thiocyanatocadmates modified by various amine molecules and Cl(-)/CH3COO(-) ions: synthesis, structural characterization, thermal behavior and photoluminescence properties.

Under ambient conditions, reactions of CdCl2/Cd(CH3COO)2, SCN(-) and various organic amine molecules in strongly acidic solutions afforded the five new thiocyanatocadmates [H2(abpy)][CdCl2(SCN)2] (abpy = azobispyridine) 1, [H(apy)][Cd(SCN)3] (apy = 4-aminopyridine) 2, [H(ba)]2[CdCl2(SCN)2] (ba = tert-butylamine) 3, [H2(tmen)][Cd3Cl6(SCN)2] (tmen = N,N,N',N'-tetramethylethylenediamine) 4, and [H(dba)]2[Cd2(CH3COO)2(SCN)4] (dba = dibutylamine) 5. In compound 2 only, the CH3COO(-) ions in Cd(CH3COO)2 were completely displaced by SCN(-), producing a chained thiocyanatocadmate [Cd(SCN)3](-). In the other four compounds, the Cl(-) or CH3COO(-) ions appeared in the final inorganic anion frameworks. In compound 1, the Cl(-) ions doubly bridge the Cd(2+) centers, forming a one-dimensional (1-D) infinite chain, and the SCN(-) group exists in a terminal form, whereas in compound 3, the reverse situation is observed. Due to a trans-mode arrangement for two terminal Cl(-) or SCN(-) ions around each Cd(2+) center, the inorganic anion chains in compounds 1 and 3 both show a linear shape. In compound 4, Cd(2+) and Cl(-) first aggregate to form a 1-D endless chain with a composition of Cd3Cl6, which can be described as a linear arrangement of the open double cubanes. SCN(-) serves as the second connector, propagating the Cd3Cl6 chain into a three-dimensional (3-D) network with the occluded H2(tmen)(2+) cations. In compound 5, the SCN(-) groups doubly bridge the Cd(2+) centers, forming a 1-D zigzag-shape chain. The formation of the zigzag chain likely derives from chelation of the CH3COO(-) group to the Cd(2+) center. The thermal behavior and the photoluminescence properties of the title compounds were also investigated.

5-(3',4'-Dicarboxylphenoxy)isophthalate/5-(2',3'-Dicarboxylphenoxy)isophthalate-Based 3D Cadmium(II) Coordination Polymers: Synthesis, Structure, and Sensing of Nitrobenzene.

5-(3',4'-Dicarboxylphenoxy)isophthalic acid (H4 L1) and 5-(2',3'-dicarboxylphenoxy)isophthalic acid (H4 L2) were reacted with Cd2+ salt with/without the assistance of N-donor ligands, creating five 3D CdII coordination polymers [Cd2 (L1)(H2 O)5 ]⋅H2 O (1), [Cd2 (L1)(bpe)(H2 O)] (bpe=1,2-bis(4-pyridyl)ethene; 2), [Cd2 (L1)(bpa)(H2 O)] (bpa=1,2-bis(4-pyridyl)ethane; 3), [Cd2 (L1)(bpp)] (bpp=1,3-bis(4-pyridyl)propane; 4), and [Cd2 (L2)(bpp)2 (H2 O)2 ]⋅H2 O (5). Crystal-structure analysis reveals 1) in 1, phthalate moieties for L1 link Cd1 centers into a 1D slightly helical chain; Cd2 centers act as bridges, linking 1D helical chains into a 3D network with a (3,5)-connected topology; 2) in 2-4, although Cd2+ centers were further modified by the introduction of organic bases, L1 molecules still link Cd2+ centers into 3D networks, which can all be simplified as pcu topology; 3) in 2-4, phthalate moieties first link Cd2+ centers into an oligomer, in which carboxylate-bridged discrete or rod-shaped secondary building units (SBUs) are found (tetranuclear SBU in 2 and 3, rod-shaped SBU in 4); and 4) in 5, L2 molecules link Cd2+ centers into a 2D (4,4) net; introduced bpp molecules serve as pillar linkers, extending Cd2+ -L2 layers into a 3D network of 5. The sensing abilities of 2-5 for nitrobenzene (NB) were investigated. Results revealed that they could all serve as fluorescence probes to sense NB at ppm concentrations.

4-(4-carboxyphenoxy)phthalate-based coordination polymers and their application in sensing nitrobenzene.

Under hydro(solvo)thermal conditions, two 4-(4-carboxyphenoxy)phthalate-based three-dimensional (3-D) coordination polymers: [Cd3(cpph)2(bpa)2(H2O)]·0.5H2O (cpph = 4-(4-carboxyphenoxy)phthalate, bpa = 1,2-bis(4-pyridyl)ethane) 1, and [H2(bpp)][Mn2(cpph)2(H2O)2] (bpp = 1,2-bis(4-piperidyl)propane) 2 were isolated. In both compounds, the cpph molecules extend the metal ions into a 3-D network: a (4,6)-connected net for 1 and a simple 6-connected net with a pcu topology for 2. The introduced bpa or bpp molecule stabilizes the 3-D metal-cpph architecture in the form of linker or guest molecule. The sensing ability of 1 was investigated, revealing that it can be used as a fluorescence probe to sense nitrobenzene at ppm concentrations.

New Zn²âº coordination polymers constructed from acylhydrazidate molecules: synthesis and structural characterization.

By employing two types of hydrothermal in situ ligand reactions (acylation of N2H4 with aromatic polycarboxylic acids, reduction of 3-nitrophthalhydrazide by N2H4), three new acylhydrazidate-extended Zn(2+) coordination polymers [Zn2(3-apth)(atrz)2] (3-apth = 3-aminophthalhydrazidate; atrz = 3-amino-1,2,4-triazolate) 1, [Zn2(4-apth)(atez)2] (4-apth = 4-aminophthalhydrazidate; atez = 5-aminotetrazolate) 2, and [Zn(3-cppth)(H2O)] (3-cppth = 4-(3-carboxyphenoxy)phthalhydrazidate) 3 were obtained. X-ray single-crystal diffraction analysis revealed that (i) compound 1 possesses a 3-D structure. The triazolate molecules link the Zn(2+) ions to form a 2-D layer with a (6,3) topology. Then the acylhydrazidate molecule acts as the second linker, extending the (6,3) nets into a 3-D network of compound 1; (ii) compound 2 also exhibits a 3-D structure. The acylhydrazidate molecules first link the Zn(2+) ions into a 1-D infinite chain. The tetrazolate molecules propagate further the chains into a 3-D (4,4)-connected net (symbol: (4·6(4)·8)2(4(2)·6(2)·8(2))); (iii) compound 3 only shows a 1-D chain structure. The photoluminescence analysis indicates that the three title compounds all emit light, especially compound 2 which emits extremely strong blue light. The side group on the phthalhydrazidate molecule plays a crucial role in the emission behaviors of compounds 1-3. At 77 K, the activated compound 2 can adsorb N2 with a capacity of ca. 41.0 cm(3) g(-1).

Construction of acylhydrazidate-extended metal-organic frameworks.

Under hydrothermal conditions, the reactions of Ba(2+)/Zn(2+), aromatic polycarboxylic acids and N2H4 with or without oxalic acid were carried out, affording four new acylhydrazidate-extended metal-organic frameworks (MOFs) [Ba(pmdh)] (pmdh = pyromellitdihydrazidate) 1, [Ba(sdpth)(H2O)2]·0.5H2O (sdpth = 4,4'-sulfoyldiphthalhydrazidate) 2, [Ba2(cpth)2(H2O)2] (cpth = 4-carboxylphthalhydrazidate) 3 and [Zn2(pdh)2(ox)]·H2O (ox = oxalate, pdh = pyridine-2,3-dicarboxylhydrazidate) 4. The acylhydrazidate molecules pmdh, sdpth, cpth and pdh in compounds 1-4 derived from the hydrothermal in situ acylation of N2H4 with aromatic polycarboxylic acids. X-ray single-crystal diffraction analysis revealed that (i) in compound 1, the pmdh I molecules link the Ba(2+) ions into a two-dimensional (2D) layer with a (4,4) topology, and then the pmdh II molecules extend these layers into a three-dimensional (3D) network; (ii) in compound 2, the sdpth molecules link the Ba(2+) ions to form a one-dimensional (1D) square tube. Interestingly, the tubes are further linked into a 3D supramolecular network via the N-H···O interactions, creating synchronously big channels; (iii) in compound 3, the cpth I molecules link the Ba1 ions into a 3D network with a (10,3) topology. Ba2 and cpth II are distributed on the channels; (iv) in compound 4, Zn(2+) and pdh aggregate to form two types of Zn4(pdh)4 clusters. The ox molecules act as the secondary linkers, extending the Zn4(pdh)4 secondary building units (SBUs) into a 3D network with a 6(6) topology. The photoluminescence analysis indicates that compounds 3 and 4 emit green light with maxima at 495 nm for 3 (λ(ex) = 397 nm), and 522 nm for 4 (λ(ex) = 395 nm), respectively. At 77 K, the activated 2 and 4 can adsorb N2 in amounts of 58.31 cm(3) g(-1) for 2 and 38.38 cm(3) g(-1) for 4, respectively.

New hybrid Cd(II) compounds: synthesis and structural characterization.

In an acidic solution, the room-temperature reactions of CdX2 (X(-) = Cl(-), Br(-) or CH3COO(-)) and organic N-heterocyclic molecules with or without SCN(-)/SeCN(-)/dca(-) (dca(-) = dicyanamide) created the five new hybrid Cd(ii) compounds [H2(4,4'-dtdpy)]2[CdBr4]SO4·2.5H2O (dtdpy = dithiodipyridine) 1, [H(2,2'-dtdpy)]2[CdBr4] 2, [(Hbim)2CdCl2(SCN)2] (bim = 2,2'-biimidazole) 3, [H2(pip)][Cd(SCN)4] (pip = piperazine) 4 and [CdL2] (L = HNC(OH)N(-)CN) 5. X-ray single-crystal diffraction analysis revealed that: (i) compound 1 is a double salt of [H2(4,4'-dtdpy)]SO4 and [H2(4,4'-dtdpy)][CdBr4], [H2(4,4'-dtdpy)]SO4 shows a two-dimensional (2D) supramolecular layer structure and [H2(4,4'-dtdpy)][CdBr4] is distributed in the space between the supramolecular layers; (ii) compounds 2 and 3 are mononuclear molecular entities. Of those, 2,2'-dtdpy and bim were only in situ monoprotonated; (iii) compound 4 contains a 2D supramolecular layered structure which is based on [Cd(SCN)4](2-) chains H2(pip)(2+)via NSCNNpip interactions; (iv) the three-dimensional (3D) compound 5 exhibits a rutile-related (4·6(2))2(4(2)·6(10)·8(3))-topology. The ligand L originates from the in situ nucleophilic addition of H2O with one -CN group of dca(-). Upon excitation, the solid-state compounds 3 and 4 emit blue light, and the solid-state compound 5 emits violet light.

Synthesis, structural characterization and photoluminescence property of three Zn(2+)/Mn(2+)-acylhydrazidate complexes and two acylhydrazide molecules.

By employing the hydrothermal in situ acylation of N2H4 with aromatic polycarboxylic acids, three new acylhydrazidate-containing complexes [Zn(N2H4)(dphkh)]·H2O (dphkh = 4,4'-diphthalhydrazidatoketone hydrazone) 1, [Zn(npth)2] (npth = naphthalhydrazidate) 2 and [Mn(mpdh)2(H2O)2]·2H2O 4, and two new acylhydrazide molecules [bpth]·0.5H2O (bpth = 3,3'-biphthalhydrazide) 3 and [(chpth)2] (chpth = 4-chloro-5-hydrazinophthalhydrazide) 5 were obtained. It is noteworthy that (i) compound 1 is a layered Zn(2+) coordination polymer with a mixed ligand of dphkh and N2H4. The nucleophilic addition of the keto spacer with N2H4 also occurred, forming the ketone hydrazone; (ii) compound 2 is a unique example of a npth-extended coordination polymer, exhibiting a double-chain structure; (iii) apart from the acylation of N2H4 with dcpha (dcpha = 4,5-dichlorophthalic acid), one Cl was substituted by N2H4, generating a new monoacylhydrazide molecule of compound 5. The solid-state photoluminescence analysis revealed that compounds 1 and 5 exhibit strong luminescence with the maximum at 490 nm for 1 and 535 nm for 5, whereas compounds 2 and 3 show weaker emissions with the peaks at 510 nm for 2 and 440 nm for 3.