Interesting Coordination Polymers Research Articles

Silver(I) Coordination Polymer Ligated by Bipyrazole Me4bpzH2, [Ag(X)(Me4bpzH2)] (X = CF3CO2− and CF3SO3−, Me4bpzH2 = 3,3′,5,5′-Tetramethyl-4,4′-bipyrazole): Anion Dependent Structures and Photoluminescence Properties

Coordination polymers of transition metal ions are fascinating and important to coordination chemistry. One of the ligands known to form particularly interesting coordination polymers is 3,3',5,5'-tetramethyl-4,4'-bipyrazole (Me4bpzH2). Group 11 metal(I) ion coordination polymers, other than those of copper(I), are relatively easy to handle because of their low reactivity towards dioxygen and moisture. However, the known silver(I) coordination polymers often have poor solubility in common solvents and so cannot be easily analyzed in solution. By using a tetramethyl substituted bipyrazole ligand, we have synthesized more soluble silver(I) complexes that contain the trifluoromethyl group in the coordinated ions CF3CO2- and CF3SO3- in [Ag(CF3CO2)(Me4bpzH2)] and [Ag(CF3SO3)(Me4bpzH2)]. We determined both structures by single-crystal X-ray analysis at low temperatures and compared them in detail. Moreover, we investigated the solution behavior of these coordination polymers by 1H-NMR, IR, Raman, UV-Vis spectroscopies, and their low-temperature, solid-state photoluminescence. The high-energy band at ~330 nm corresponded to ligand-centered (bipyrazole) fluorescence, and the low-energy band at ~400 nm to ligand-centered phosphorescence resulting from the heavy atom effect.

Chiral Ligand-Driven Systematic Synthesis of Coordination Polymers with Non-centrosymmetric Structures.

Chirality is an important concept in chemistry revealing intriguing optical properties such as circular dichroism (CD), circularly polarized luminescence (CPL), etc. As one of the non-centrosymmetric (NCS) classes, chiral materials with extended structures may exhibit unique nonlinear optical (NLO) properties, such as second-harmonic generation (SHG). In this Concept article, a series of recently discovered NCS coordination polymers (CPs) from use of carefully designed chiral organic ligands are reviewed. Combining several metal cations such as lanthanides, lead, zinc, and cadmium with rigid chiral ligands has resulted in interesting CPs with both polar and nonpolar structures. Detailed structures, SHG properties, and structure-property relationships are provided. The importance of hyperpolarizability formed by intermolecular hydrogen boding interactions to SHG is emphasized.

Construction of coordination polymers based on a rigid tripodal nitrogen-containing heterotopic ligand that designed by mixed-donors strategy

Five new coordination polymers (CPs), namely, [Co(DIPT)2]n (HDIPT = 5-(3,5-di(1H-imidazol-1-yl)phenyl)-2H-tetrazole, 1), [Zn(DIPT)2]n (2), {[Cu(DITP)2(H2O)2]·3H2O}n (3), and{[Cu(DITP)]·DMF}n (4 and 5) based on a rigid tripodal nitrogen-containing heterotopic ligand were obtained under hydrothermal conditions. Compounds 1–2 are isostructural and exhibit 3D frameworks with relative rare two-folded interpenetrating (3,6)-connected pyr network topologies. Compound 3 is a 2D layer with (4,4) network topology if consider Cu(II) as topological node and DIPT- ligand as linker. Compounds 4–5 are topological supramolecular isomers obtained from pre-synthesized and in situ formed HDIPT, respectively. The coordination modes of Cu(I) ion and DIPT- ligand, as well as the 1D zigzag chain building block in compounds 4 and 5 are quite similar, but they are with different 4-connected gis and sra topologies, respectively. In the frameworks, the tetrazolyl group has more contributions to the formation of well-defined building blocks, while the imidazolyl group has more contributions to the linkage of the building blocks. The combination of both tetrazolyl group and imidazolyl are suitable for constructing new interesting CPs. Furthermore, the thermal stabilities and solid-state fluorescent properties of selected compounds have been investigated.

Iron metallascorpionate possessing multiple binding sites: Formation of 3-D hexagonal iron-potassium coordination polymer

The reaction of three equivalents of 5-(2,4-dihydroxyphenyl)-1H-tetrazole (H3dhptz) with iron(III) perchlorate in the presence of potassium hydroxide afforded the metallascorpionate framework. By simple recrystallization, an interesting coordination polymer, [K4.5Fe(dhptz)1.5(Hdhptz)1.5DMF7(H2O)3.5]n, was obtained. It possesses two potassium ions with either κ3-O or κ3-N binding modes, resulting in an array of K–Fe–K metal ions and a short Fe–K distance (3.427Å). One scorpionate ligand possesses 4.5 potassium ions at six different positions in the solid state by means of the bridging oxygen atoms of the DMF solvent. Further coordination modes between the potassium ions and water/DMF provide a one-dimensional (1-D) metallascorpionate array and allow the formation of a 3-D hexagonal coordination network.

Structural versatility of four coordination polymers based on 5-(1-oxoisoindolin-2-yl)isophthalic acid: Magnetic and luminescent properties

Four interesting coordination polymers, namely [Co(IDPA)(phen)(H2O)]n (1), [Co(IDPA)(bpp)(H2O)]n·2n(H2O) (2), [Zn(IDPA)(py)]n (3), and [Pb(IDPA)(H2O)]n (4) (H2IDPA=5-(1-oxoisoindolin-2-yl)isophthalic acid, phen=1,10-phenanthroline, bpp=1,3-bis(4-pyridyl)propane, py=pyridine), have been successfully synthesized under solvothermal conditions and structurally characterized. Single-crystal X-ray diffraction analyses indicate that compound 1 shows a zigzag chain, while compounds 2–4 exhibit two-dimensional wavelike or flat layer structures with the same uninodal 4-connected sql topology. These results reveal that different metal centers with the presence of auxiliary ligands maybe play a significant role in the construction process of coordination polymer. Furthermore, compounds 1 and 2 display weak antiferromagnetic interactions in the system. Interestingly, because H2IDPA is a coplanar ligand with large rigid π-conjugated system, it exhibits a strong blue emission with the quantum yield (QY) up to 4.41%. Furthermore, compound 3 is a 2D layer structure and its QY is largely increased to 22.52%. Besides, compound 4 shows a multiple emissions from blue to yellow and falls within the white region of the 1931 CIE chromaticity diagram. Therefore, it is suggested to turn on the fluorescence by building the fluorophore within metal-organic frameworks.

Metalloligand-induced Synthesis of Two Cu(I)–M (M=Ni, Co) Heterobimetallic Coordination Polymers: Structures, Thermal and Luminescence Properties

Two interesting heterobimetallic coordination polymers (CPs), {[Ni(4-pytpy)2]2[Cu4(N(CN)2)7](NO3)(DMF)(DMSO)(H2O)4}n (1) and {[Co(4-pytpy)(N(CN)2)]2[Cu2(N(CN)2)4]}n (2), have been synthesized based on different metalloligands [M(4-pytpy)2]2+ (M=Ni 1, Co 2) (4-pytpy = 4′-(4-pyridyl)-2,2′:6′,2″-terpyridine). CPs 1 and 2 have been well characterized by elemental analysis, IR spectroscopy, thermal analysis and single-crystal X-ray diffraction. Both CPs 1 and 2 crystallize in the triclinic crystal system with the P-1 space group but feature different structures. CP 1 exhibits a unique one dimensional double-chain structure, while CP 2 possesses an infinite 2D network structure. It is interesting to note that the metalloligand [Co(4-pytpy)2]2+ in CP 2 was decomposed into [Co(4-pytpy)]2+. Thermal analysis indicates that the chain structure of CP 1 begins to collapse after about 360 °C, while CP 2 can be stable up to 300 °C. The solid-state luminescence properties of CPs 1 and 2 have also been investigated.

Two Energetic Cobalt(II) Coordination Polymers Derived from Isomeric Ligands

Isomer is sometimes fundamental to the formation of the resulting compounds. The design and preparation of coordination compounds based on isomers is of tremendous paramount since they have a lot in common but simultaneously some difference, which can lead to variation of both the topologies and properties. Solvothermal reactions of Hn-pytza (n = 3, 4) with Co(ClO4)2·6H2O, afforded two interesting coordination polymers, one dimensional [Co(3-pytza)2(H2O)2]n·2nH2O (1) and three dimensional [Co(4-pytza)2]n (2), where Hn-pytza = 5-(n-pyridyl)tetrazole-2-acetic acid (n = 3, 4). The thermal decomposition behavior of the two compounds were characterized by the differential scanning calorimetry (DSC) and thermogravimetric-differential thermogravimetric (TG-DTG), showing [Co(4-pytza)2]n is superior to [Co(3-pytza)2(H2O)2]n·2nH2O in terms of energetic performance. Furthermore, the entropy of activation (∆S), enthalpy of activation (∆H), and free energy of activation (∆G) were calculated, as well.

Influence of the Different Dicarboxylate Ligands on The Topological Net of Manganese(II) Coordination Polymers: Syntheses, Crystal Structures. and Luminescent Properties

AbstractThe self‐assembly of MnII ions and 1,4‐bis(2‐methyl‐imidazole‐1‐yl)benzene (bip) with two different dicarboxylate ligands, benzophenone‐4,4′‐dicarboxylic acid (H2bda) and 1,4‐naphthalenedicarboxylic acid (H2nda) via hydrothermal synthesis resulted in two interesting coordination polymers, [Mn(bda)(bip)]n (1) and [(Mn(nda)(bip)0.5(H2O)]n (2). Their structures were determined by single‐crystal X‐ray diffraction and elemental analyses, as well as IR spectroscopy. Complex 1 exhibits an unusual polycatenated 2D+2D→3D framework. Complex 2 shows a twofold interpenetrated pcu net. In addition, the solid‐state photoluminescent properties of 1 and 2 were investigated at room temperature.

Hydrothermal Syntheses, Crystal Structures, and Luminescent Properties of Two MnII Coordination Polymers: From Two-Fold Interpenetrated pcu Topological Net to Polycatenated 2D+2D→3D Framework

Using a hydrothermal synthesis, the self-assembly of MnII ions and 1,4-bis(1-imidazol-yl)-2,5-dimethyl benzene with two dicarboxylate ligands, 2-nitrobenzene-1,4-dicarboxylic acid (2-H2ata) and 5-methylbenzene-1,3-dicarboxylic acid (5-CH3-H2ip) constructed two interesting coordination polymers: [Mn(2-ata)(bimb)]n (1) and {[Mn(5-CH3-ip)(bimb)1.5]·2H2O}n (2), where bimb refers to 1,4-bis(1-imidazol-yl)-2,5-dimethyl benzene. Their structures were determined by single-crystal X-ray diffraction, elemental analysis, and infrared spectroscopy. Complex 1 exhibits a 2-fold interpenetrated pcu net. Complex 2 shows an unusual polycatenated 2D+2D→3D framework. In addition, the solid-state photoluminescent properties of 1 and 2 were investigated at room temperature.

Studies on Metal–Organic Frameworks of Cu(II) with Isophthalate Linkers for Hydrogen Storage

Hydrogen (H2) is a promising alternative energy carrier because of its environmental benefits, high energy density, and abundance. However, development of a practical storage system to enable the "Hydrogen Economy" remains a huge challenge. Metal-organic frameworks (MOFs) are an important class of crystalline coordination polymers constructed by bridging metal centers with organic linkers. MOFs show promise for H2 storage owing to their high surface area and tuneable properties. In this Account, we summarize our research on novel porous materials with enhanced H2 storage properties and describe frameworks derived from 3,5-substituted dicarboxylates (isophthalates) that serve as versatile molecular building blocks for the construction of a range of interesting coordination polymers with Cu(II) ions. We synthesized a series of materials by connecting linear tetracarboxylate linkers to {Cu(II)2} paddlewheel moieties. These materials exhibit high structural stability and permanent porosity. Varying the organic linker modulates the pore size, geometry, and functionality to control the overall H2 adsorption. Our top-performing material in this series has a H2 storage capacity of 77.8 mg g(-1) at 77 K, 60 bar. H2 adsorption at low, medium, and high pressures correlates with the isosteric heat of adsorption, surface area, and pore volume, respectively. Another series, using tribranched C3-symmetric hexacarboxylate ligands with Cu(II), gives highly porous (3,24)-connected frameworks incorporating {Cu(II)2} paddlewheels. Increasing the length of the hexacarboxylate struts directly tunes the porosity of the resultant material from micro- to mesoporosity. These materials show exceptionally high H2 uptakes owing to their high surface area and pore volume. The first member of this family reported adsorbs 111 mg g(-1) of H2, or 55.9 g L(-1), at 77 K, 77 bar, while at 77 K, 1 bar, the material adsorbs 2.3 wt % H2. We and others have since achieved enhanced H2 adsorption in these frameworks using combinations of polyphenyl groups linked by alkynes. The maximum storage achieved for one of the enhanced materials is 164 mg g(-1) at 77 K, 70 bar, but because of its low density, its volumetric capacity is only 45.7 g L(-1). We attribute the significant adsorption of H2 at low pressures to the arrangement of the {Cu24(isophthalate)24} cuboctahedral cages within the polyhedral structure. Free metal coordination positions are the first binding sites for D2, and these frameworks have two types of Cu(II) centers, one with its vacant site pointing into the cuboctahedral cage and another pointing externally. D2 molecules bind first at the former position and then at the external open metal sites. Design of ligands and complexes is key for enhancing and maximizing H2 storage, and although current materials operate at 77 K, research continues to explore routes to high capacity H2 storage materials that can function at higher temperatures.

Hydrogen-bond-directed self-assembly of a novel 2D → 3D polythreading with finite components based on rigid ligand

The reactions of Cu(II) sulfate with 4-Amino-1,2,4-triazole (Atrz) and 1,3,5-Benzenetricarboxylic acid (H 3BTC) gave a novel interesting coordination polymer {[Cu 5(BTC) 4(HAtrz) 2(H 2O) 9]} n . The structure contains 2D undulated molecular layers. The BTC side arms can thread through the voids of adjacent polymeric units guided by strong intermolecular hydrogen bonding interactions, exhibiting an unusual 2D → 3D polythreading with finite components.

Two Coordination Polymers with Rare Topologies Based on Copper(II) and Ligands Generated by In Situ Reactions

AbstractHydro(solvo)thermal in situ reactions provide an important strategy for the construction of coordination polymers with interesting structures and topologies. In our study, two interesting coordination polymers [Cu(C2O4)(L1)0.5(H2O)2.5]n (1) (L1 = 3,5‐bipyridyl‐1,2,4‐triazole) and [Cu3O2(NO3)2(L2)2(H2O)2]n (2) {L2 = 5‐(3‐pyridyl)‐1,2,4‐triazolo[3,2‐c](7‐aza‐1‐H‐indazole)} were prepared through an in situ ligand deaminization reaction and an in situ ligand intramolecular amination cyclization reaction, respectively. To the best of our knowledge, the formation of an indazole cycle through an in situ intramolecular amination cyclization reaction is reported for the first time. The two coordination polymers present a rare NiP2 topology and kgd topology. Their magnetic properties have also been studied.

Urothermal synthesis of a photoluminescent zinc coordination polymer

Abstract Solvent plays an important role in the self-assembly of metal-organic frameworks (MOFs). It has been demonstrated that the urea derivatives are a new kind of useful solvents, and a new synthetic method denoted as “urothermal synthesis” is emerging. Presented here are the urothermal synthesis, structure and photoluminescent property of an interesting coordination polymer {Zn3[(sip)2(tmdpy)2(e-urea)4(H2O)2](e-urea)2}n (1; sip = 5-sulfoisophthalate; tmdpy = 1.3-di(4-pyridyl)propane; and e-urea = 2-imidazolidinone) with ladder-like structure.

Three novel coordination polymers incorporating overlapped 0D Zn units, 1D zigzag Co chains and 2D interlocking 24-member Mn rings — Syntheses, structures and properties

Three new interesting coordination polymers, [Zn(PDCO)(H2O)·H2O]n (1), [Co(PDCO)(H2O)3]n (2) and [Mn(PDCO)(H2O)2]n (3), (H2PDCO = pyridine-2,4-dicarboxylic acid N-oxide), have been prepared under hydrothermal conditions and structurally characterized. Polymer 1 exhibits 0D Zn units, polymer 2 features 1D infinite zigzag Co chains. In polymer 3, four Mn atoms and four PDCO ligands form a 24-member ring and these rings are interlocked to form a 2D infinite layer. Compounds 1–3, with systematic variation in dimensionality from 0D to 1D to 2D, are the first examples of metal coordination polymers into which pyridine-2,4-dicarboxylic acid N-oxide has been introduced. In addition, the photoluminescent properties of 1 as well as the magnetic behavior of 2 have been investigated.

Cobalt(II) coordination polymers assembled from polycarboxylate and benzotriazole: Syntheses, structures and physical properties

Hydrothermal reactions of cobalt(II) salt with H 2CAM or H 2SDBA and HBTA in the presence of NaOH afford two interesting coordination polymers, Co 3(CAM) 2(BTA) 2 ( 1) and Co 3(SDBA) 2(BTA) 2 ( 2) (H 2CAM = camphoric acid, H 2SDBA = 4,4′-dicarboxybiphenyl sulfone, HBTA = benzotriazole), both of which have been structurally characterized by single-crystal X-ray, elemental analysis, infrared spectroscopy, and thermogravimetric analysis. Complexes 1 and 2 are isostructural and possess two-dimensional covalent network, comprising an unusual linear Co(II) chains of mixed T d– O h– T d geometries. Temperature-dependent magnetic measurements indicate the existence of antiferromagnetic interactions in both 1 and 2.

Topological Diversification in Metal‐Organic Frameworks: Secondary Ligand and Metal Effects

AbstractA series of interesting coordination polymers have been prepared by the combination of a V‐shaped 4,4′‐oxybis(benzoic acid) (H2oba) and neutral organonitrogen ligands with different metal ions, namely, {[M(oba)(bpe)]·H2O}n [M = Mn (1), Co (2)], [M(oba)(N3)]n [N3 = dipyridin‐2‐ylamine; M = Cd (3), Cu (4)] and {[Zn(oba)(N5)]·2H2O}n (5) [bpe = 1,2‐bis(4‐pyridyl)ethene, N5 = bis(pyridin‐2‐yl)pyridine‐2,6‐diamine]. The framework structures of these neutral polymeric complexes have been determined by single‐crystal X‐ray diffraction studies. Compound 1 has a threefold pcu‐type network structure. Although 2 has the same ligands and coordination modes as 1, it consists of corrugated 2D layers formed of a series of squares, which allows the sheets to interpenetrate in an unusual 2D → 3D parallel fashion. Polymers 3 and 4 exhibit double‐helical chains formed by π–π stacking interactions from the phenyl rings of the N3 ligands. Compound 5 forms a 2D supramolecular architecture directed by hydrogen bonding between the NH groups of the N5 ligand, the uncoordinated carboxylate oxygens, and the intercalated water molecules. This work markedly indicates that the effect of auxiliary ligands is significant in the construction of these network structures, which are also well regulated by the metal centers. Thermogravimetric analysis (TGA) and XRPD results for compound 1 as well as luminescent properties for compounds 3 and 5 are discussed.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

Syntheses, Structures, and Photoluminescent and Magnetic Studies of Metal−Organic Frameworks Assembled with 5-Sulfosalicylic Acid and 1,4-Bis(imidazol-1-ylmethyl)-benzene

Four novel interesting coordination polymers, [Cd3(bix)3(SSA)2(H2O)4]n (1), [Co(bix)2(HSSA)(H2O)·H2O]n (2), [Ni(bix)2(HSSA)(H2O)·H2O]n (3) and [Mn(bix)2·(HSSA)·2H2O]n (4) (bix = 1,4-bis(imidazol-1-ylmethyl)-benzene; H3SSA = 5-sulfosalicylic acid), have been synthesized under hydrothermal conditions and structurally characterized. Polymer 1 features a two-dimensional (2D) infinite layer framework built from tri-cadmium clusters, which is further stacked along the c-axis via strong interlayer hydrogen-bond interactions to form a three-dimensional (3D) network. Both polymers 2 and 3 exhibit one-dimensional (1D) double-stranded chains, which are connected by strong hydrogen-bond interactions along the c-axis to result in 2D layers; in addition, the layers are further stacked along the b-axis by π−π interactions. Polymer 4 also possesses 1D double-stranded chains. It is noteworthy that ligand HSSA in compound 4 is not coordinated to the metal ions but only acts as an anion moiety to compensate the charge balan...

Syntheses, Structures, and Physical Properties of Three Novel Metal−Organic Frameworks Constructed from Aromatic Polycarboxylate Acids and Flexible Imidazole-Based Synthons

Three novel interesting coordination polymers, [Cd3(SIP)2(bbi)5·3H2O]n (1), [Co3(SIP)2(bix)4(2H2O)·2H2O]n (2), and [Cd(2,5-pydc)2(bix)1.5·H2O]n (3) (SIP = 5-sulfoisophthalic acid monosodium salt; bbi = 1,1‘-(1,4-butanediyl)bis(imidazole); bix = 1,4-bis(imidazol-1-ylmethyl)-benzene; 2,5-pydc = pyridine-2,5-dicarboxylic acid), have been isolated under hydrothermal conditions and structurally characterized. Polymer 1 has a 3D complicated framework comprised of an infinite 1D ladder-like chain and 2D layer structure. Polymer 2 features a 3D hydrated framework with uncoordinated water molecules trapped in the pores. Polymer 3 is a 2D infinite layer framework, which is further interconnected by hydrogen-bond interactions to lead to a 3D supramolecular architecture. Compounds 1 and 3 exhibit medium-strong fluorescent emissions in the solid state at room temperature and could be significant in the field of photoactive materials.

Self-assembly of silver polymers based on flexible isonicotinate ligand at different pH values: syntheses, structures and photoluminescent properties

Two interesting coordination polymers, [Ag 8(IN) 6(NO 3) 2] 1 and [Ag(IN)(HIN)] 1/2 [Ag(IN)] 2 (HIN=isonicotinic acid) have been synthesized hydrothermally at different pH values. 1 crystallizes in the triclinic space group P-1, with a = 10.987 ( 2 ) Å , b = 11.625 ( 2 ) Å , c = 17.323 ( 4 ) Å , α = 75.87 ( 3 ) ° , β = 80.87 ( 3 ) ° , γ = 76.50 ( 3 ) ° , V = 2074.0 ( 7 ) Å 3 and Z = 2 . Compound 1 is the first example of a bilayer framework, in which both single layers are connected by the bond interactions (Ag–O) between Ag from two two-dimensional (2D) single layers generated by the A building block and O atoms from one-dimensional (1D) chain constructed by the B building block, in which coordination modes of IN were reported for the first time. 2 crystallizes in the monoclinic space group P2(1)/ c, with a = 8.1668 ( 16 ) Å , b = 19.611 ( 4 ) Å , c = 7.4083 ( 15 ) Å , β = 92.90 ( 3 ) ° , V = 1185.0 ( 4 ) and Z = 4 . Compound 2 exhibits a 2D plywood-like structure assembled by hydrogen bonds and weak Ag–O interactions.

Syntheses, crystal structures and properties of three one-dimensional coordination polymers generated from flexible bipyridyl ligands

Three new interesting coordination polymers, [Cu 2(μ-4,4′-bpp)(OAc) 4] n ( 1), [Cu(μ-3,3′-bpp)(SCN) 2] n ( 2) and [Zn(μ-4,4′-bpp) 2(dca) 2·0.5H 2O] n (Hdca=dicyanamide) ( 3) have been synthesized and structurally characterized. Compounds 1– 3 consist of different one-dimensional zigzag chains arising from the different positions of donor atoms (4,4′-bpp or 3,3′-bpp). Thermogravimetric analyses show that the three compounds have very similar thermal behaviors and are stable up to about 270 °C. Compound 3 exhibits a blue luminescence with the emission maximum at ca. 457 nm upon excitation at 370 nm which is assigned to the intraligand emission from 4,4′-bpp ligand.