Zigzag Chain Coordination Research Articles

Structures, luminescent properties, and volatile iodine detection of Zn(II) based zigzag coordination chains

Two isostructural luminescent Zn coordination polymers, [Zn(ip)(Cz-Pr-3,6-bpy)2]n·2n(H2O) (1) and [Zn(hip)(Cz-Pr-3,6-bpy)2]n·3n(H2O) (2), where Cz-Pr-3,6-bpy ​= ​3,6-bis(pyridin-4-yl)-9-n-propyl-9H-carbazole, H2ip ​= ​isophthalic acid, and H2hip ​= ​5-hydroxyisophthalic acid, showing good chemical stability have been synthesized under hydro(solvo)thermal conditions. Coordination polymers 1 and 2 both show Zn–dicarboxylate zigzag chains with each Zn(II) center anchoring by two monodentate Cz-Pr-3,6-bpy pendants. Luminescence studies indicate that 1 and 2 emit bright cyan- and blue-light fluorescence, respectively, in solid-state. Of note, 1 and 2 both show detectable fluorescence on–off response with high quenching efficiencies of >97% and visual color change from pale yellow to darker brown upon exposure to iodine vapors. The I2-loaded capacity is gravimetrically determined to be 0.162 ​g ​g−1 for 1 and 0.012 ​g ​g−1 for 2. This makes 1 and 2 to be good dual-responsive optical chemosensors for volatile iodine detection.

Syntheses, Crystal Structures, and Properties of Two d10 Metal Complexes Based on Ferrocenyl Ligands Bearing Pyrazolyl Pyridine Substituents

Two new complexes, namely, [Cd2(L1)2(NCS)4(DMF)2] · 4H2O (I) and {[Zn3(L2)4(SO4)3(H2O)8] · 3DMF · 6H2O} n (II) have been synthesized through self-assembly of Cd(II) or Zn(II) salts with ferrocenyl ligands bearing pyrazolyl pyridine substituents. The two compounds were characterized by IR spectra, element analysis, X-ray powder diffraction, single-crystal X-ray diffraction (СIF files CCDC nos. 949526 (I), 949527 (II)), and thermogravimetric analysis. Complex I crystallizes in the monocline space group P21/c and exhibits a discrete dinuclear structure. The adjacent dinuclear molecules are packed into a 1D linear chain through the hydrogen-bond interactions. Complex II is a neutral one-dimensional infinite zigzag coordination chain. The 3D packing diagram of II contains two types of voids and the solvated DMF and water molecules filled them and stabilized by the hydrogen bonds. In addition, the redox properties of both complexes I and II have also been investigated.

Two manganese(II) coordination polymers driven by (iso)nicotinoyl-hydrazone blocks and pseudohalide ancillary ligands: syntheses, structural features, and magnetic properties

Two coordination polymers, [Mn2(μ-L1)2(μ-N3)2]n (1) and [Mn(μ-HL2)(SCN)2]n (2), were assembled in a single-pot from MnCl2·4H2O, HL1 (2-acetylpyridine isonicotinoylhydrazone) or HL2 (2-acetylpyridine nicotinoylhydrazone) and ancillary ligand sources (NaN3 or NH4NCS). The products were fully characterized, including by single-crystal X-ray diffraction, which revealed a 2-D metal–organic layer in 1 and a 1-D zigzag coordination chain in 2. Both 1 and 2 are constructed from six-coordinate Mn(II) nodes that adopt distorted octahedral (MnN5O) environments; the adjacent nodes are driven by the μ-L1 and μ-N3 linkers in 1 or μ-HL2 linkers in 2 to form different metal–organic networks. Their topological classification was performed, disclosing the hcb and 2C1 topology in 1 and 2, respectively. Different weak non-covalent interactions promote dimensionality extension. Variable-temperature magnetic susceptibility measurements were carried out, revealing weak ferromagnetic and antiferromagnetic interactions in 1 and 2, respectively.

White Light Emissive Dy(III) Single-Molecule Magnets Sensitized by Diamagnetic [Co(III) (CN)6 ](3-) Linkers.

The self-assembly of Dy(III) -3-hydroxypyridine (3-OHpy) complexes with hexacyanidocobaltate(III) anions in water produces cyanido-bridged {[Dy(III) (3-OHpy)2 (H2 O)4 ] [Co(III) (CN)6 ]}⋅H2 O (1) chains. They reveal a single-molecule magnet (SMM) behavior with a large zero direct current (dc) field energy barrier, ΔE=266(12) cm(-1) (≈385 K), originating from the single-ion property of eight-coordinated Dy(III) of an elongated dodecahedral geometry, which are embedded with diamagnetic [Co(III) (CN)6 ](3-) ions into zig-zag coordination chains. The SMM character is enhanced by the external dc magnetic field, which results in the ΔE of 320(23) cm(-1) (≈460 K) at Hdc =1 kOe, and the opening of a butterfly hysteresis loop below 6 K. Complex 1 exhibits white Dy(III) -based emission realized by energy transfer from Co(III) and 3-OHpy to Dy(III) . Low temperature emission spectra were correlated with SMM property giving the estimation of the zero field ΔE. 1 is a unique example of bifunctional magneto-luminescent material combining white emission and slow magnetic relaxation with a large energy barrier, both controlled by rich structural and electronic interplay between Dy(III) , 3-OHpy, and [Co(III) (CN)6 ](3-) .

Syntheses and crystal structures of coordination polymers of a porphyrin ligand bearing two pyridyl and two carboxyl moieties

In this work, we designed and synthesized a porphyrin-based ligand, 5,15-bis(4-carboxyphenyl)-10,20-dipyridyl porphyrin, DCDPP (H4L), which bears two carboxyl and two pyridyl moieties. Coordination of Mn(II) and Zn(II) acetates with DCDPP afforded two novel coordination polymers, [MnHL]n (1) and [ZnH2L]n·nCH3COOH (2), respectively. Single crystal X-ray diffraction analyses revealed that complex 1 exhibits 2D coordination networks, which are further linked through hydrogen bonds to form a 3D network structure. In complex 2, 1D zigzag coordination chains were generated and further linked through hydrogen bonds to form a 2D structure. Interestingly, the carboxyl moieties in these complexes are noncoordinated, and the pyridyl moieties are either coordinated or noncoordinated, and the noncoordinated carboxyl and pyridyl moieties are involved in intermolecular hydrogen bonds, which are favorable for forming the hydrogen-bonded networks.

A Novel Porphyrin-Based Ligand Containing Four 4,4′-Dipyridylamine Moieties: Syntheses, Structures, and Luminescent Properties of Mn(II), Cu(II), Zn(II), and Cd(II) Coordination Polymers

The design and syntheses of porphyrin-based ligands are attractive for creating coordination assemblies with novel structures and intriguing properties. In this work, we designed and synthesized a novel porphyrin-based ligand 5,10,15,20-tetrakis(4,4′-dipyridylaminophenylene)porphyrin (TDPAP, H2L) by the introduction of four peripheral 4,4′-dipyridylamine moieties to a porphyrin platform. Starting from this novel ligand, the protonated form of the ligand H4LCl2·2CH3OH·2H2O (1) and four coordination polymers [Mn(III)Mn(II)LCl3(DMF)]n (2), [Cu4L(CH3COO)5(HCOO)(CH3COOH)(H2O)3]n·nCH3COOH·nH2O (3), [Zn3L(CH3COO)4]n (4), and [Cd2H2L(CH3COO)4]n·nDMF·nCH3COOH·2nH2O (5) were synthesized. Single crystal X-ray diffraction analyses revealed that a rich structural diversity was observed for these compounds due to the coordination of the multiple peripheral pyridines as well as the porphyrin core. 1 displays a hydrogen bonded one-dimensional (1D) structure composed of [(H2O)2Cl2]2– moieties. Complex 2 shows interpenetrated two-dimensional (2D) coordination networks, which are further linked by π···π stacking interactions to afford a three-dimensional (3D) structure. 3 shows a 2D sheet composed of 50- and 70-membered metallomacrocycles. In complex 4, 1D zigzag coordination chains were generated and further linked to form a 2D structure. Complex 5 has a stairlike 2D structure formed by the linkage of 1D coordination chains through the bridging of binuclear [Cd2(CO2)4] subunits. In these compounds, TDPAP shows a unique coordination behavior. It may bind 4–7 metal centers, and it demonstrates conformational flexibility and the ability to form intermolecular hydrogen bonds and π···π interactions, which contribute to the formation of novel supramolecular structures. On the basis of the novel structures, the solid state emissions of the compounds were also investigated.

Supramolecular assemblies based on the interaction of a copper dication with alky-substituted cucurbit[6]urils

In this study, we describe the interaction of copper cations with alkyl-substituted cucurbiturils (SQ[6])s in the absence and presence of a third species, and show how the corresponding supramolecular assemblies depend on the addition of the third species. In the absence of the third species, the SQ[6]s resulted in similar coordination with copper cations and the formation of supramolecular assemblies as the unsubstituted cucurbituril (Q[6]). The Cu2+ cation was coordinated to a cyclopentanocucurbit[6]uril (CyP6Q[6]) with the counter anion NO3− and formed a zigzag coordination chain. In contrast, the Cu2+ cation coordinated to a symmetrical tetramethylcucurbit[6]uril (TMeQ[6]) with the counter anion Cl− and formed a tubular coordination polymer. However, when SO42− was introduced into the Cu2+–TMeQ[6] system, only isolated complexes consisting of linear coordination polymers of Cu2+ to TMeQ[6] were formed. By comparison, when the organic molecule p-phenylenediamine was introduced into the CuCl2–TMeQ[6]–HCl system, no Cu2+–TMeQ[6] complexes were formed at all but p-phenylenediamine@TMeQ[6] host–guest inclusion complexes were observed.

Supramolecular framework incatena-poly[[(nitrato-κO)silver(I)]-μ-(R,S)-2-(pyridin-4-ylsulfinyl)pyrimidine-κ3N,O:N′

In the title complex, [Ag(NO(3))(C(9)H(7)N(3)OS)](n), η(1):η(1):η(1):μ(2)-bridging 2-(pyridin-4-ylsulfinyl)pyrimidine (pypmSO) ligands with opposite chiralities are alternately arranged to link the Ag(I) cations through two N atoms and one sulfinyl O atom of each ligand, leading to an extended zigzag coordination chain structure along the [ ̅201] direction. An FT-IR spectroscopic study shows a decreased stretching frequency for the η(1)-O-bonded S=O group compared with that of the free ligand. The parallel chains are arranged and interconnected via O(S=O)···π(pyridine/pyrimidine) and C-H(pyridine)···O(NO(3)(-)) interactions to furnish a layer almost parallel to the ac plane. Along the b axis, the layers are stacked and stabilized through anion(NO(3)(-))···π(pyrimidine) interactions to form a three-dimensional supramolecular framework. The ligand behaviour of the new diheterocyclic sulfoxide and the unconventional O(S=O)···π(pyridine/pyrimidine) and anion(NO(3)(-))...π(pyrimidine) interactions in the supramolecular assembly of the title complex are presented.

Solvent-regulated assembly of three new polymeric CdII 5-fluoroisophthalates with mono-, di-, and trinuclear nodes: Syntheses, structures, and luminescent properties

Three new polymeric CdII complexes, [Cd(fip)(MeOH)3]n (1), {[Cd2(fip)2(H2O)5]·4H2O}n (2), and {[Cd3(fip)4(H2O)2][Cd(DMF)2(H2O)4]·2DMF}n (3), have been prepared from the reactions of CdII acetate with a rigid fluorinated ligand 5-fluoroisophthalic acid (H2fip) under different solvent systems. Complex 1 shows a 1D zigzag coordination chain with a mononuclear [Cd(COO)(MeOH)3] unit, and complex 2 displays a 2D neutral layered structure containing a dinuclear [Cd2(COO)4(H2O)5] entity, while complex 3 presents a 2D anionic coordination network with the linear trinuclear [Cd3(COO)8(H2O)2] clusters as the linking nodes. The results clearly suggest that the judicious choice of solvent systems does play a critical role in the construction of coordination frameworks with distinct connectivity and dimensionality. The spectroscopic, thermal, and luminescent properties of 1–3 have also been investigated.

Synthesis, crystal structure, and fluorescence of a 2-D coordination polymer

A 2-D coordination polymer with mixed ligands, [Zn2(BDC)(4,4′-bipy) (HCOO)2] (1) (BDC, 1,4-benzenedicarboxylate; 4,4′-bipy, 4,4′-bipyridine), has been synthesized by solvothermal reaction. Compound 1 provides the first coordination polymer structure constructed by bridging BDC, 4,4′-bipy, and formate. Both BDC and 4,4′-bipy link zincs alternatively, resulting in a zigzag coordination chain; adjacent chains are further linked by formates to form an infinite extended 2-D folding screen layer. The synthesis mechanism and fluorescence property are discussed.

Zn(II) and Cd(II) Coordination Polymers Assembled from a Versatile Tecton 5-Nitro-1,2,3-benzenetricarboxylic Acid and N,N′-Donor Ancillary Coligands

Five novel zinc(II) and cadmium(II) metal−organic coordination polymers with a tricarboxyl tecton and N-donor ancillary ligands, {[Zn(Hnbta)(2,2′-bipy)]·H2O}n (1), {[Cd3(nbta)2(2,2′-bipy)2(H2O)2]}n (2), {[Cd3(nbta)2(bpa)2]}n (3), {[Zn2(nbta)(OH)(bpa)1.5]·2H2O}n (4), and {[Zn3(nbta)2(bpp)2(H2O)2]}n (5) (H3nbta = 5-nitro-1,2,3-benzenetricarboxylic acid, 2,2′-bipy = 2,2′-bipyridine, bpa = 1,2-bi(4- pyridyl)ethane, and bpp = 1,3-bi(4-pyridyl)propane), have been prepared and characterized by elemental analysis, IR spectra, and X-ray diffraction. Complex 1 has a two-dimensional (2D) bilayer supramolecular network constructed from one-dimensional (1D) zigzag coordination chains via π···π interactions, whereas 2 exhibits a three-dimensional (3D) supramolecular network assembled from 1D coordination arrays through π···π interactions and weak C−H···O interactions. Complex 3 features a (4,5)-connected self-penetrating 3D coordination net with a (43·65·82)(43·62·8)(44·64·82)(45·65) topology. The 3D framework of 4 can...

Syntheses, crystal structures, and magnetic properties of five new coordination compounds bearing ferrocenedicarboxylate ligands

Five new coordination compounds, {[Mn(L)(CH3OH)2] · CH3OH · H2O} n (1), {[Cd(L)(DMF)2(H2O)] · H2O} n (2), {[Co(L)(CH3OH)4] · CH3OH}2 (3), {[Cd(L)(phen)(CH3OH)] · CH3OH} n (4), and {[Mn(L)(phen)(H2O)] · CH3OH} n (5) (L = 5-ferrocene-1,3-benzenedicarboxylic acid, phen = 1,10-phenanthroline) were obtained from different metal salts and L with or without 1,10-phen under mild conditions. Complex 1 is a 1-D ladder-like chain composed of 8-membered rings A and 16-membered rings B, which arrange alternately. Complex 2 is an infinite linear chain, further bridged to form a parallel double chain through different hydrogen-bond interactions. Complex 3 is a discrete dinuclear structure, while 4 is a neutral 1-D infinite zigzag coordination chain. Complex 5 is a 1-D linear chain with phen and ferrocene groups of L as pendants hanging on the different sides of the main chain. Variable temperature magnetic susceptibilities of 1 were measured and weak antiferromagnetic exchange interactions between the neighboring Mn(II) ions were found with J = −0.95 cm−1.

One-dimensional Zn(II) oligo(phenyleneethynylene)dicarboxylate coordination polymers: Synthesis, crystal structures, thermal and photoluminescent properties

The rigid, π-conjugated dicarboxylic acid 1,4-bis-[2-(4-carboxyphenyl)ethynyl]-2,5-dihexylbenzene {HO 2C[PEP(hexyl) 2EP]CO 2H} has been used to synthesise the new crystalline coordination polymers {Zn(O 2C[PEP(hexyl) 2EP]CO 2)(DMF) 2} ( 1) and {Zn(O 2C[PEP(hexyl) 2EP]CO 2)(DEF) 2} ( 2) in N,N-dimethylformamide (DMF) and N,N-diethylformamide (DEF), respectively, under mild conditions. Single-crystal X-ray crystallography revealed that 1 and 2 are isostructural and consist of uncharged zigzag coordination chains in which [Zn(formamide) 2] 2+ fragments are bridged by (O 2C[PEP(hexyl) 2EP]CO 2) 2− ligands. The zigzag chains possess different intra-chain Zn⋯Zn⋯Zn angles due to the different volumes of the coordinating formamide molecules and subtle differences in the hydrophobic inter-chain interactions. Upon heating 1 and 2 to 200 °C, removal of the coordinating formamide molecules occurs, yielding the formamide-free compounds 1-DMF and 2-DEF of composition {Zn(O 2C[PEP(hexyl) 2EP]CO 2)}. According to powder X-ray diffraction and FT-IR spectroscopy studies, these materials are not crystalline but still possess partial ordering of intact, yet modified coordination chains in a structural arrangement which appears to be related to the respective parent compounds. Compounds 1, 2, 1-DMF and 2-DEF exhibit blue photoluminescence. The emission maxima of 1-DMF and 2-DEF are red-shifted by ca. 25 nm with respect to λ max of 1 and 2, respectively.

Reactivity of 4-amino-3,5-bis(pyridin-2-yl)-1,2,4-triazole, structures and magnetic properties of polynuclear and polymeric Mn(ii), Cu(ii) and Cd(ii) complexes

Five new complexes were obtained from solution or hydrothermal reactions of M(OAc)(2) (M = Mn, Cu and Cd) or CuCl(2) with 4-amino-3,5-bis(pyridin-2-yl)-1,2,4-triazole (abpt) and NaN(3) or 1,3,5-benzenetricarboxylic acid (btcH(3)) in different molar ratios. Structural analysis reveals that Cd(abpt) units in [Cd(abpt)(mu(1,1)-N(3))(2)](n) (1) are bridged by double mu(1,1) end-on (EO) azides into 1D zigzag coordination chains. Similar structural motifs, i.e. the chelation of abpt to the metal center and the double bridges of EO azides, are found in [Mn(4)(abpt)(4)(mu(1,1)-N(3))(8)(H(2)O)(2)] (2). The terminal aqua molecules and the monodentate N(3)(-) groups lead to the formation of a tetranuclear complex rather than a polymeric compound. The abpt underwent deamination in the presence of copper ions during the process of coordination and became 3,5-bis(pyridin-2-yl)-1,2,4-triazolate (bpt-H) in 3-5. [Cu(4)(bpt-H)(4)(N(3))(4)].4.5H(2)O (3) is a neutral tetranuclear grid-like complex, in which the azides act as monodentate ligands. A similar [Cu(4)(bpt-H)(4)](4+) grid-like unit was found in [Cu(4)(bpt-H)(4)(mu-btcH)Cl(2)].2H(2)O (4) and a pair of symmetry-related copper atoms are bridged by the mu-btcH(2)(-) coligand in a butterfly-shaped structure. In [Cu(2)(bpt-H)(mu(6)-btc)(H(2)O)](n) (5), the tetranuclear {Cu(4)(mu-bpt-H)(2)(mu(3)-carboxylate)(2)}(4+) units are bridged by mu(6)-btc(3-) ligands in a 2D step-like layer structure. Temperature-dependent magnetic susceptibility measurements reveal that the double mu(1,1)-N(3)(-) bridges in 2 transmit the ferromagnetic interactions between Mn(2+) centers (J(1) = J(2) = +3.09(4) cm(-1), g(Mn(II)) = 2.02(1)), and the mu-(bpt-H)(-) bridges transmit moderate antiferromagnetic interactions in both 3 (J = -12.78(13) cm(-1)) and 4 (J(1) = -14.96(11) cm(-1)). In 4 the antiferromagnetic coupling via the mu-btcH(2-) bridge was found as the second coupling pathway (J(2) = -9.48(7) cm(-1)). The coexistence of ferromagnetic and antiferromagnetic coupling between four Cu(2+) centers occurs in 5 (J(1) = -0.88(3) cm(-1) and J(2) = +5.01(2) cm(-1)). The magneto-structural relationship for tetranuclear copper pyrazolate/triazolate compounds has been discussed.

Towards tuning the packing and entanglement of zigzag coordination chains by terminal ligands

Solvothermal reactions of trans-stilbene-4,4'-dicarboxylic acid (H(2)STDC) and zinc(ii) acetate in the presence of systematically varied terminal ligands afforded a series of supramolecular architectures with formula [Zn(STDC)(py)(2)].py (1), [Zn(STDC)(bipy)(H(2)O)].0.5py.H(2)O (2), [Zn(STDC)(biql)] (3), [Zn(STDC)(phen)].solv (solv = DMSO, 4a; DMF, 4b), where py = pyridine, bipy = 2,2'-bipyridine, biql = 2,2'-biquinoline, phen = 1,10-phenathroline. X-Ray analyses revealed that all the compounds consist of infinite 1D zigzag polymer chains. Investigations based on intermolecular interactions illustrate that the chelate terminal ligands play a critical role in determining the packing/entangling modes of the chains and the porosity of the final three-dimensional architectures. In compounds 1 and 2, the weak hydrogen bonding and/or pi-pi stacking interactions assemble the parallel chains into diamond nets with four- and two-fold interpenetration, respectively. In compound 3, the hydrogen bonding and pi-pi stacking interactions collaborate to arrange the chains in two different directions, generating a 3D supramolecular architecture with high catenation. The most interesting packing occurs in 4. Extensive pi-pi stacking interactions involving the terminal and bridging ligands arrange the chains in four different directions, and the chains are hierarchically entangled to produce an unprecedented 3D microporous framework with high stability. Based on comparative investigations, the effects of the terminal and bridging ligands on the packing of zigzag chains have been discussed. The reversible guest inclusion properties of 2 and 4 have also been demonstrated.

Crystal structures and spectroscopic behavior of monomeric, dimeric and polymeric copper(II) chloroacetate adducts with isonicotinamide, N-methylnicotinamide and N, N-diethylnicotinamide

Substituted pyridines provide structural rigidity and thus permit the metal coordination geometry to guide the direction of propagation of the hydrogen-bonded links between building blocks. In this paper we present the crystal structures and spectroscopic properties of monomeric, dimeric and polymeric copper(II) chloroacetates with isonicotinamide (INA), N-methylnicotinamide (MNA) and N, N-diethylnicotinamide (DENA). The molecular structure of [Cu(ClCH 2CO 2) 2(INA) 2] 2 ( 1) consists of a rather interesting dinuclear molecule with copper atoms bridged by anti, anti- O, O′ bridging oxygens of two chloroacetate anions. Each copper atom is octahedrally coordinated thus forming a CuN 2O 4 core with two nitrogens, originating from two different isonicotinamide molecules, in trans positions. This complex is one of a very few examples of this rare type of structure in which both carboxylate oxygen anions are coordinated to two copper metal ions. The crystal structure of 1 revealed an infinite 1-D linear hydrogen-bonded chain formed by discrete molecules [Cu(ClCH 2CO 2) 2(INA) 2] 2 connected by strong hydrogen bonds between two amide groups. This structure is the first example, where two pairs of amide groups are involved in hydrogen bonding connecting two molecules. The X-ray structure of the complex [Cu(CCl 3CO 2) 2(INA) 2] n ( 3) revealed a tetragonal bipyramidal environment about the copper(II) atom. This structure represents the first example of copper(II) complex, where isonicotinamide acts as a bridging ligand. Strong intramolecular hydrogen bonds, N–H⋯O, create two eight-membered metallocycle rings which stabilizes the molecular structure. The crystal structure of 3 consists of 2-D sheets of a metal–organic framework. The coordination environment of the copper(II) atom in [Cu(CCl 3CO 2) 2(MNA) 2(H 2O) 2] · 2H 2O ( 6 · 2H 2O) is an elongated tetragonal bipyramid. Strong intramolecular hydrogen bond interactions involving an axial coordinated water molecule and a carboxylic oxygen atom stabilize the molecular structure. The crystal structure of [Cu 2(ClCH 2CO 2) 4(DENA)] n ( 7) shows that the complex is an extended zigzag coordination chain of alternating binuclear paddle-wheel units of the bridging tetracarboxylate type Cu 2(ClCH 2CO 2) 4 and N, N-diethylnicotinamide molecules. This complex represents the first example of copper(II) carboxylates where N, N-diethylnicotinamide molecule acts as a bidentate bridging ligand connecting binuclear paddle-wheel units. The variation in DENA coordination in the polymeric chain can be described by the following formula: –[Cu 2(ClCH 2CO 2) 4]–(DENA- N, O)– [Cu 2(ClCH 2CO 2) 4]–(DENA- O, N)–. All complexes were characterized by electron paramagnetic resonance (EPR) spectroscopy and IR spectroscopy. The present study shows that the pyridine-carboxyamides are very suitable molecules that can be employed as ligands in the construction of extended arrays of transition metal-containing molecules linked via hydrogen bonds.

Unprecedented 3D entanglement of 1D zigzag coordination polymers leading to a robust microporous framework

One-dimensional zigzag coordination chains in four different directions are hierarchically entangled to generate an unprecedented 3D interwoven framework, which exhibits permanent porosity and guest selectivity.

Syntheses, crystal structures and properties of two Mn(II) complexes of DTPA-bisamide derivative

Two new Mn(II) complexes of DTPA-bisamide derivative ligand (H 5L), MnH 3L · CH 3OH · 2.5H 2O ( 1) and [Mn 2.5L(H 2O) 8] · 5.25H 2O ( 2) were synthesized and structurally characterized. X-ray structure analyses showed that the two complexes have quite different structures. In complex 1, Mn(II) cation adopts a novel seven-coordinate distorted pentagonal bipyramid polyhedron, while in complex 2, four different Mn(II) coordination environments are observed and form a novel 1-D zigzag coordination chain. Complexes 1 and 2 construct the 2-D and 3-D supramolecular architectures through versatile hydrogen bond interactions, respectively. The relaxivity of the two complexes were also determined. The higher R 1 value of 2 means that it may be applied in magnetic resonance imaging contrast agents.

Zn(μ- l)Cl 2] ∞: a one-dimensional (1-D) zigzag coordination chain exhibiting unique two-dimensional (2D) hydrogen-bonding supramolecular architecture

Self-assembly of the versatile bridging ligand 2,5-bis(3-pyridyl)-1,3,4-oxadiazole ( l) with ZnCl 2 in CHCl 3–H 2O medium affords a neutral one-dimensional zigzag coordination polymer [Zn(μ- l)Cl 2] ∞ ( 1), which has been characterized by IR, elemental analyses, thermogravimetric analysis (TGA) and X-ray diffraction techniques. The crystal structure of 1 reveals that the ligand molecules bridge the tetrahedral Zn II centers (ZnN 2Cl 2) in the unprecedented transoid conformation, forming a one-dimensional zigzag coordination chain. The inter-chain C–H···Cl hydrogen bonds between the pyridine rings and the coordinated chloride anions extend these 1-D coordination frameworks to result in a novel 2-D supramolecular architecture, and there exist significant edge-to-edge π–π stacking interactions between the inter-chain neighboring pyridyl rings of the ligand, which may further stabilize this structure.

Extended Network via Axial Cu-Br Linkages of Zig-zag Coordination Chains of Copper(II) Ions Bridged Alternately by trans-Oxamidate and End-on Azide Groups

Abstract The zig-zag coordination chains [Cu2(trans-oxen)(N3)(Br)]n[H2oxen=N,N′-bis(2-aminoethyl)oxamide] with alternating bridges of trans-oxamidate and azide in bis-terdentate and end-on mode, respectively, are held together via axial Cu-Br linkage in a unique fashion to form an extended structure.