Vertex Symbol Research Articles

Cd(II)/Mn(II)/Co(II)/Ni(II)/Zn(II) Coordination Polymers Built from Dicarboxylic Acid/Tetracarboxylic Acid Ligands: Their Structural Diversity and Fluorescence Properties

Six Cd(II)/Mn(II)/Co(II)/Ni(II)/Zn(II) coordination complexes are formulated as [Cd2(X2-)2(μ3-O)2/3]n (1), [Mn2(X2-)2(μ3-O)2/3]n (2), {[Co1.5(Y4-)0.5(4,4'-bpy)1.5(OH-)]·2H2O}n (3), {[Ni(X2-)(4,4'-bpy)(H2O)2]·4H2O}n (4), [Zn(m-bdc2-)(bebiyh)]n (5), and [Cd(5-tbia2-)(bebiyh)]n (6) (H2X = 3,3'-(2,3,5,6-tetramethyl-1,4-phenylene) dipropionic acid. H4Y = 2,2'-(2,3,5,6-tetramethyl-1,4-phenylene)bis(methylene) dimalonic acid, bebiyh = 1,6-bis(2-ethyl-1H-benzo[d]imidazol-1-yl)hexane, m-H2bdc = 1,3-benzenedicarboxylic acid, and 5-H2tbia = 5-(tert-butyl)isophthalic acid) were obtained by hydrothermal reactions and structurally characterized. Complexes 1 and 2 have a 6-connected 3D architecture and with several point symbols of (36·46·53). Complex 3 features a 5-connected 3D net structure with a point symbol of (5·69). Complex 4 possesses a 4-connected 2D net with a vertex symbol of (44·62). Complex 5 is a 3-connected 2D network with a point symbol of (63). Complex 6 is a (3,3)-connected 2D network with a point symbol of (63)2. In addition, complexes 1 and 4 present good photoluminescence behaviors. The electronic structures of 1 and 4 were investigated with the density functional theory (DFT) method to understand the photoluminescence behaviors.

Characterization and analysis of ring topology of zeolite frameworks

The topology of zeolite frameworks and of associated tetrahedral sites (T-sites) are commonly characterized by their associated rings, typically defined as some set of closed paths or cycles through a framework that cannot be decomposed into shorter cycles. These ring descriptors have been used to identify feasible zeolite topologies, to describe the similarity and differences between zeolites, to identify sites or voids of catalytic relevance, and as machine learning fingerprints. Numerous definitions and algorithms for finding zeolite rings have been proposed and applied throughout the literature. Here we report an analysis of rings and T-sites in a large number of zeolite frameworks using Zeolite Simulation Environment, a Python package that implements an efficient algorithm presented by Goetzke and Klein for finding rings in arbitrary frameworks. We compare the result of a number of common and new ring definitions applied to a large number of common zeolite frameworks. We discover previously unrecognized rings in a number of frameworks. We show that the vertex symbol, a common approach used to characterize T-sites, misses important parts of the stereochemistry around a T-site, and propose an alternative definition. This tool provides an effective platform for characterizing zeolite and T-site structures useful for building models and doing machine learning.

3D Ag(I) coordination polymer constructed from a flexible pyridyloxycyclotetraphoshazene linker: Synthesis, crystal structure and dye adsorption properties

The reaction of the flexible polydentate ligand octakis(3-pyridyloxy)cyclotetraphosphazene (O3PyCP) with AgNO3 afforded a new coordination polymer, [Ag2(O3PyCP)](NO3)2]n (1). The resultant coordination polymer was characterized by single-crystal X-ray crystallography and infrared spectroscopy. The ligand O3PyCP acts in the κ6N coordination mode by connecting six Ag(I) ions to form a 3D coordination framework. Topological analysis confirms that compound 1 shows a 3D structure with a fsc topology with the vertex symbol of {44.610.8}{44.62}. The thermal stability of O3PyCP and compound 1 were investigated by thermogravimetric analysis. The study of dye adsorption by tetracyclophosphazene-based coordination polymers was carried out for the first time in this study. According to dye adsorption studies, compound 1 adsorbs anionic methyl orange (MO) from water, but does not exhibit any adsorption behaviour toward cationic methylene blue (MB). A pseudo-second-order kinetic model is suitable to explain the adsorption kinetics.

Syntheses, structures and magnetic properties of two CoII/NiII isostructural coordination polymers based on an asymmetric semirigid tricarboxylate ligand.

Two new isostructural complexes, namely, poly[aqua[μ3-2-(4-carboxyphenoxy)terephthalato-κ3O1:O4:O4'](1,10-phenanthroline-κ2N,N')cobalt(II)], [Co(C15H8O7)(C12H8N2)(H2O)]n or [Co(μ3-Hcpota)(phen)(H2O)]n, I, and poly[aqua[μ3-2-(4-carboxyphenoxy)terephthalato-κ3O1:O4:O4'](1,10-phenanthroline-κ2N,N')nickel(II)], [Ni(C15H8O7)(C12H8N2)(H2O)]n or [Ni(μ3-Hcpota)(phen)(H2O)]n, II, have been synthesized by solvothermal reactions. Complexes I and II were fully characterized by IR spectroscopy, elemental analyses, thermogravimetric analyses, and powder and single-crystal X-ray diffraction. They both present two-dimensional structures based on [M2(μ-COO)2]2+ (M= CoII or NiII) dinuclear metal units with a fes topology and a vertex symbol (4·82). Interestingly, the positions of the two dimeric metal motifs and the two partially deprotonated Hcpota2- ligands reproduce regular flying butterfly arrangements flipped upside down and sharing wings in the ab plane. Magnetic studies indicate antiferromagnetic interactions (J= -5.21 cm-1 for I and -11.53 cm-1 for II) in the dimeric units, with Co...Co and Ni...Ni distances of 4.397 (1) and 4.358 (1) Å, respectively, that are related to double syn-anti carboxylate bridges.

Zeolite LTA structure generation by Coordination Sequence and Vertex Symbol

Abstract A graph theory based computational program CVdecoder is proposed that enable us to construct a zeolite LTA structure topology from Coordination Sequence and Vertex Symbol information. During the generation process, a critical size of cluster (graph) denoting as “Minimal Fingerprint Structure (MFS)” is found. The generation process after the MFS formation is no longer requiring more topological information but vertex transitive. The cluster is also smallest characteristic cluster that could only be found in LTA, that may provide a useful view of zeolite polymorph selective nucleation.

Structural diversity, topology and luminescent properties of a two-dimensional Cd(II) coordination polymer incorporating 4,4′-dipyridyl and 4,4′-sulfonyldibenzoic acid

A new Cd(II) derivative, [Cd2(H2O)4(bipy)(sdba)2]∙10H2O (1), is synthesized hydro(solvo)thermally by the combination of divalent cadmium nitrate tetrahydrate as metal salt, an N-donor ancillary ligand 4,4′-bipyridine (bipy), and the flexible aromatic carboxylate, 4,4′-sulfonyldibenzoic acid (sdba), as organic linker. Single crystal X-ray diffraction analysis reveals that the Cd(II) atoms show a distorted trigonal bipyramidal environment. In the asymmetric unit, both the carboxylate and the N-donor connectors bridge pairs of cadmium ions; this ultimately leads to the formation of a set of undulated sheets formed by fused rings comprising six cadmium centers, two bipy and four sdba ligands. Considering the cadmium ions as nodes and the ligands as connectors, the structure can be described as a stack of 3-c uninodal nets of the type hcb, with point symbol {44.62} and vertex symbol [6.6.6]. The encapsulation of the Cd(II) derivative displays a moderate luminescent property.

Syntheses, structures, magnetic properties and luminescence of four coordination polymers based on an asymmetric semirigid tricarboxylate ligand

In this work, four new complexes, [Mn(μ3-Hcpoia)(phen)(H2O)]n1, [Mn2(μ4-Hcpoia)2(μ2-bib)(H2O)2]n2, [Zn(μ2-Hcpoia)(phen)(H2O)]n3, and [Zn2(μ2-Hcpoia)2(μ2–4,4′-bpy)(H2O)2]n·2nH2O 4 (H3cpoia = 4-(4-carboxyphenoxy)isophthalic acid, phen = phenanthroline, bib = 1,4-di(1H-imidazol-1-yl)benzene, 4,4′-bpy = 4,4′-bipyridine) have been synthesized by solvothermal reactions. Complexes 1–4 were fully characterized by IR spectroscopy, elemental analyses, thermogravimetric analyses, powder and single-crystal X-ray diffraction. Complexes 1 and 2 present two-dimensional (2D) structures based on the dinuclear Mn(II) secondary building units with the vertex symbols of (4.82) and (32.44)(34.46.64.7), respectively. Complex 3 possesses one-dimensional (1D) structure and reveals a uninodal 2-connected chain with the 2C1 topology. Complex 4 exhibits a 1D ladder-like double chain, containing a 1D metal–organic chain interconnected by the 4,4′-bpy ligand with the vertex symbol of (42.6). Such a rich structural diversity of 1–4 is driven by various factors, including the type of the metal(II) ions and the ancillary ligands, as well as the coordination mode of ligand. Complexes 1 and 2 show antiferromagnetic interactions (J = −0.719 cm−1 for 1, and J = −6.981 cm−1 for 2) in dimeric units with the Mn-Mn distances of 4.451(1) and 3.151(5) Å, respectively, that are related to double syn−anti carboxylate bridges and four bis-bidentate carboxylate groups with syn−syn and μ–oxo modes. The solid-state luminescent behaviors of 3, 4 were also investigated systematically.

Rhombellanic Crystals and Quasicrystals

Design of some crystal and quasicrystal networks, based on rhombellane tiling,is presented. [1,1,1]Propellane,is a synthesized organic molecule; its hydrogenated form, the bicyclo[1.1.1]pentane,may be represented by the complete bipartite graph K2,3 which is the smallest rhombellane. Topology of translational and radial structures involving rhombellanes is described in terms of vertex symbol, connectivity sequence, ring sequence and map operations relating structures to their seeds. It is shown, by alternating sum of ranked substructures, that radial structures represent complex constructions of higher rank. Basic properties of rhombellanes, coloring included, are outlined.

A new Cu(II) three-dimensional network with 4,4′-oxybis benzoic acid: structural diversity, EPR, and magnetism

The copper derivative {[Cu4(oba)4(H2O)4]∙H2O}n (1) has been hydro(solvo)thermally synthesized by combining flexible 4,4′-oxybis benzoic acid (oba) and divalent copper nitrate. As a result of the potential coordination modes of carboxylate oxygens from the oba ligand, the aforementioned complex leads to the formation of an interesting 3D framework, as evidenced by single-crystal X-ray diffractometry. Concerning the topology in 1, the dimers [Cu2C4O8] are nodes of a 5-fold 4-connected uninodal net of the type lvt, with point symbol {42.84} and vertex symbol [4.4.84.84.88.88]. The encapsulation of the copper coordination polymer displays a moderate luminescent property. On temperature-dependent magnetic study, it reveals that the magnetic behaviour of 1 can be associated to a strong antiferromagnetic coupling between the two Cu(II) ions.

3-(Pyridin-4-yl)acetylacetone: a donor ligand towards mercury(II) halides and a versatile linker for complex materials.

The ditopic organic molecule 3-(pyridin-4-yl)acetylacetone (HacacPy) acts as a pyridine-type ligand towards HgX2 (X = Cl, Br, I). The nature of the anion and the ligand-to-cation ratio dominate the outcome of the reaction. Two different coordination compounds form with HgCl2, namely a ligand-rich mononuclear complex, HgCl2(HacacPy)2, and a ligand-deficient one-dimensional chain polymer, [Hg(μ-Cl)2(HacacPy)]1∞, with five-coordinated HgII cations. Two compounds are also observed for HgBr2, a molecular complex isomorphous to the chloride derivative and a chain polymer with the composition [Hg(μ-Br)Br(HacacPy)]1∞, in which the cations are four-coordinated. The ligand-rich mononuclear and ligand-deficient polymeric chloride and bromide complexes may be interconverted via thermal degradation and mechanochemical synthesis. In contrast to the chloride and bromide compounds, the reaction product with HgI2 does not depend on the ligand-to-cation ratio but corresponds to [Hg(μ-I)I(HacacPy)]1∞, isomorphous to the bromide derivative. The N-coordinated HacacPy complexes could not be deprotonated and further crosslinked with a second cation. Synthesis of mixed-metal products could be achieved, however, by deprotonation of the acetylacetone moiety in HacacPy and formation of tris-chelated Fe(acacPy)3 and Al(acacPy)3 complexes in the first step. These mononuclear building blocks act as bridging poly(pyridine) ligands towards HgII halides and form two structure types. The first represents a one-dimensional ladder, with the tris(ligand) complexes acting as triconnected nodes and the HgII halides acting as linkers. In the alternative unprecedented product, both the tris(ligand) complexes and the [HgX2(μ-X)HgX] groups act as equivalent triconnected nodes. They form a uninodal two-dimensional coordination network with vertex symbol 4.82 and fes topology.

Controlled stepwise synthesis of a Cu-MOF: Transmetallation of a magnesium precursor to a three-dimensional framework with very high solvent content

Abstract A copper metal-organic framework (MOF) was synthesized by transmetalation. The ditopic ligand 3-(3,5-dimethyl-pyrazol-4-yl)pentane-2,4-dione is introduced via its Mg precursor complex in which it is oxygen-coordinated. After transmetallation, the ligand acts as N,O,O′ linker between dinuclear, sulfato-bridged Cu(II) nodes. The resulting three-dimensional solid crystallizes in the chiral space group I213, with more than half of its cell volume occupied by disordered methanol and dichloromethane molecules: the coordination framework encloses a large solvent-filled region along [1 1 1] which coounts for 54.8% of the crystal volume. The structure collapses upon removal of the clathrated solvent. Sulfate-O atoms are exposed towards the solvent region and facilitate trapping of polar guest molecules. The framework topology corresponds to a lcv net with Vertex symbol 3·3·102·102·103·103.

Synthesis, luminescent sensing based on a three-fold interpenetrating network with flexible carboxylates

A Zn-based complexes with chemical formulae {[Zn(L)0.5(4,4'-Bipy)] · 2H2O} (I) (H4L = 5,5'-(1,4-phenylene-bis(methylene))bis(oxy) diisophthalic acid), has been synthesized and structurally characterized. Single-crystal X-ray crystallography (CIF file CCDC no. 1465538) reveals that compound I shows a three-dimensional three-fold interpenetrating network simplified by a bbf topology (vertex symbol (66)2(64.82)). Complex I can work as highly sensitive sensors to Cu2+, CrO 4 2- and explosive by luminescent quenching.

A Heterobimetallic 2-D Coordination Polymer [Na2(Cu2I2(2pyCOO)4)(H2O)4]n (2pyCOO−=picolinate) within a 3-D Supramolecular Architecture

A heterobimetallic 2-D coordination polymer, [Na2(Cu2I2(2pyCOO)4)(H2O)4]n (1) (2pyCOO=picolinate) was synthesized and characterized. The complex was also structurally characterized using single X-ray diffraction studies that revealed the complex 1 having a vertex symbol of 4.82 which corresponds to fes topology. Together with hydrogen bonds and interdigitating π···π interactions, these thus facilitate the formation of 3-D supramolecular network. The nitrogen gas absorption amount of 1 at 77 K shows a small volume of N2 sorption isotherm with a small Langmuir and a Brunauer-Emmett-Teller (BET) surface area indicating that the heterobimetallic 3-D supramolecular of 1 exhibits a very weak ability of adsorbing gas.

High-Pressure Synthesis of Melilite-type Rare-Earth Nitridophosphates RE2P3N7 and a Ba2Cu[Si2O7]-type Polymorph.

High-pressure metathesis was proposed to be a gateway to the elusive class of rare-earth nitridophosphates. With this method the first ternary compounds of this class with sum formula RE2P3N7 were prepared, a melilite-type with RE = Pr, Nd, Sm, Eu, Ho, Yb (Ho2P3N7: P4̅21m, a = 7.3589(2), c = 4.9986(2) Å, Z = 2) and a Ba2Cu[Si2O7] structure type with RE = La, Ce, Pr (Pr2P3N7: monoclinic, C2/c, a = 7.8006(3), b = 10.2221(3), c = 7.7798(3) Å, β = 111.299(1)°, Z = 4). The phase relation between the two structure types was prior unknown and is here evidenced by experimental data as well as density functional theory calculations performed for the Pr2P3N7 compounds. Adequate classification of both structures types with regard to Liebau nomenclature, vertex symbol, and point symbol is made. Additionally, the tiling patterns of the monolayered structures are deducted. We demonstrate that high-pressure metathesis offers a systematic access to rare-earth nitridophosphates with an atomic ratio of P/N between 1/2 and 1/4.

Assembly of a 3D chiral Cu(I) metal–organic framework based on 4,5-dicyanoimidazole: CD spectrum, luminescence and selective gas adsorption

One chiral Cu(I) metal–organic framework {[Cu(DCI)]·0.1Cyc·0.45Nbenz}n (1) (HDCI=4,5-dicyanoimidazole, Cyc=cyclohexanol, Nbenz=nitrobenzene), was obtained under solvothermal condition. Complex 1 presents a 3D chiral porous framework with 38.2% porosity. The 3D metal–organic framework can be regarded as a PtS net with the vertex symbol of {42.84}. The gas adsorption/desorption experiments of complex 1 have been measured at 77K. Moreover, the CD spectrum and photoluminescent behavior of complex 1 have been studied.

Two new Cu(ii) and La(iii) 2D coordination polymers, synthesis and in situ structural analysis by X-ray diffraction.

Two new coordination polymers were synthesized solvothermally using 4,4'-dimethoxy-3,3'-biphenyldicarboxylic acid (H2dmbpdc), and di- and trivalent metal salts (Cu(NO3)2·2.5H2O and La(NO3)3·6H2O). Their structures were determined by single-crystal X-ray diffraction analysis, and their thermal stability was evaluated by thermogravimetric analysis. The copper compound Cu(dmbpdc)(DMF; N,N-dimethylformamide), CPO-71-Cu, is based on the well known copper acetate paddlewheel secondary building unit. The asymmetric unit comprises one copper cation with one DMF molecule and one linker molecule coordinated. The lanthanum compound La2(dmbpdc)3(DMF)(H2O)3, CPO-72-La, is formed from a dimer of nine-coordinate, edge sharing lanthanum cations. To this dimer, three water molecules and one DMF molecule are coordinated in an ordered fashion. In addition, the asymmetric unit contains three crystallographically unique linker molecules. Both CPO-71-Cu and CPO-72-La form two-dimensional layered structures, and topological analyses reveal sql topologies with point symbol 4(4)·6(2) and vertex symbol 4·4·4·4·6(2)·6(2). The thermal behavior of CPO-71-Cu was investigated in an in situ structural analysis by variable temperature powder- and single-crystal X-ray diffraction.

Ni(II) Coordination Polymers Constructed from the Flexible Tetracarboxylic Acid and Different N-Donor Ligands: Structural Diversity and Catalytic Activity

To seek the effect that condition of the complexes has on the manufacture of the biaryl compounds, seven Ni(II) complexes, namely, {[Ni(L)0.5(bpa)(H2O)]·2H2O}n (1), {[Ni2(L)(dpp)2(H2O)]·4H2O}n (2), {[Ni(L)0.5(pbmb)(H2O)]·H2O}n (3), {[Ni2(L)(bmp)2(H2O)]·7H2O}n (4), {[Ni(L)0.5(pbib)1.5]·2H2O}n (5), {[Ni2(L)(pbib)1.5]·3H2O}n (6), and [Ni(L)0.5(beb)2(H2O)]n (7) (bpa = 1,2-bis(4-pyridyl)ethane, dpp = 1,3-di(4-pyridyl)propane, pbmb = 1,1′-(1,3-propane)bis(2-methylbenzimidazole), bmp = 1,5-bis(2-methylbenzimidazol) pentane, pbib = 1,4-bis(imidazol-1-ylmethyl)benzene, beb = 1,4-bis(2-ethylbenzimidazol-1-ylmethyl)benzene), have been gained through hydro(solvo)thermal reactions of 5,5′-(hexane-1,6-diyl)-bis(oxy)diisophthalic acid ligand (H4L) with Ni(II) metal ions under the regulation and control of six N-donor ligands. 3-fold interpenetrating complex 1 belongs to a (4,4)-connected 3D bbf net with a vertex symbol of (64·82)(66) topology. 3-fold interpenetrating complex 2 presents a (4,4,4)-connected 3D bbf net wit...

Two new entangled complexes based on 4,4′-bis(1-imidazolyl)biphenyl: syntheses, structures, thermal and photoluminescent properties

Two new entangled complexes, [Zn(bibp)(L1)]·0.25H2O (1) and [Co(bibp)(H2L2)] (2) (bibp = 4,4′-bis(1-imidazolyl)biphenyl, H2L1 = 4,4′-(2,2′-oxybis(ethane-2,1-diyl)bis(oxy))dibenzoic acid, and H4L2 = 5,5′-(2,2′-oxybis(ethane-2,1-diyl)bis(oxy))diisophthalic acid), have been synthesized hydrothermally. Complex 1 features a new uninodal four-connected (65·8) net with vertex symbol 6·6·6·6·62·82, which is different from all that exhibit uninodal four-connected (65·8) nets found in the literature, including cds, dmp, ict, mok, unl and unm. Three of these nets interpenetrate. Complex 2 shows an unusual threefold 2-D → 3-D polythreaded framework, in which each 2-D wave-like net is formed by the intersection, at the shared Co nodes, of the 1-D left- and right-handed single-helical (H2L2)2− chains and the 1-D bibp meso-helices. Furthermore, the thermal and photoluminescent properties of 1 have also been studied.

Lanthanide coordination polymers: Synthesis, diverse structure and luminescence properties

The new semirigid exo-bidentate ligand incorporating furfurysalicylamide terminal groups, namely, 1,4-bis{[(2′-furfurylaminoformyl)phenoxyl]methyl}-2,5-bismethylbenzene (L) was synthesized and used as building blocks for constructing lanthanide coordination polymers with luminescent properties. The series of lanthanide nitrate complexes have been characterized by elemental analysis, IR spectroscopy, and X-ray diffraction analysis. The semirigid ligand L, as a bridging ligand, reacts with lanthanide nitrates forming three distinct structure types: chiral noninterpenetrated two-dimensional (2D) honeycomblike (6,3) (hcb, Schläfli symbol 63, vertex symbol 666) topological network as type I, 1D zigzag chain as type II and 1D trapezoid ladder-like chain as type III. The structural diversities indicate that lanthanide contraction effect played significant roles in the structural self-assembled process. The luminescent properties of EuIII, TbIII and DyIII complexes are discussed in detail. Due to the good match between the lowest triplet state of the ligand and the resonant energy level of the lanthanide ion, the lanthanide ions in EuIII, TbIII and DyIII complexes can be efficiently sensitized by the ligand.

Structural Investigation and Solid State Emission Studies of Co(II), Zn(II) and Cd(II) Coordination Polymers Built with a Bifurcated Ligand

The bifurcated ligand 5-di(1H-benzo[d]imidazol-1-yl) benzonitrile (DBIBN) under solvothermal condition, undergoes basic as well as acid hydrolysis to the corresponding carboxylic acid (DBIBA). Four new coordination polymers; {[Cd(DBIBA)(CH3COO)]} n (1), {[Zn(DBIBA)(CH3COO)]⋅H2O} n (2), {[Zn(DBIBA)(OC2H5)]⋅H2O} n (3) and {[Co(DBIBA)(CH3COO)]⋅H2O} n (4) have been synthesized under solvothermal conditions. Compound 1 has a 3D structure with uninodal 4-connected crb/BCT topology with point symbol of {4.65}. In contrast, compounds 2–4 are 2D layered structures having uninodal 3-connected hcb net with a vertex symbol of {63}. The 2D layers are further assembled to an overall 3D supramolecular architecture with strong π–π interactions between layers. Further reinforcement of the 3D assembly occurs due to an array of H-bonding interactions with lattice water molecules present within the layers. All the compounds have been characterized by single X-ray crystallography, IR spectroscopy, TGA, PXRD measurements and elemental analysis. Although the metal-free DBIBN ligand exhibits fluorescence, it is quenched in the coordination polymers.