Showing papers on "Coordination polymer published in 2004"
TL;DR: This study reports herein a 3D twofold interpenetrating NbO-type network [Cu2(m2OMe)2(L)2·(H2O)0.69]n (2) with 1D channels, which is a bridging ligand to construct new framework materials with novel structures and special properties based on combining its bridging coordination ability with its steric bulk.
Abstract: The construction of coordination networks with novel topologies and porous structures that provide new sizes, shapes, and chemical environments is of great interest in recent years, due to their intriguing structural diversity and potential for many applications. 2] In recent years many porous metal– organic frameworks with unique structures have been obtained and their adsorption properties were widely investigated, however, those with specially shaped channels such as 1D helices are rare. Metal–ligand coordination has been well used in the directed assembly of extended porous metal–organic networks, and one of the key points for such studies is the design or choice of components that organize themselves into desired patterns with useful functions. In this regard, considerable attention has been devoted to the networking ability of isonicotinic acid (1) and its derivatives, which are multifunctional ligands potentially able to act as bridging ligands to produce open lattice species with various structural topologies and large pores. In this study, we choose an analogy of 1, 9-acridinecarboxylic acid (HL), whose coordination chemistry has not been previously investigated, as a bridging ligand to construct new framework materials with novel structures and special properties based on combining its bridging coordination ability with its steric bulk. Although the coordination sites of HL and 1 are very similar, their coordination chemistry are found to be quite different due to the bulk of HL. We report herein a 3D twofold interpenetrating NbO-type network [Cu2(m2OMe)2(L)2·(H2O)0.69]n (2) with 1D channels.
560 citations
TL;DR: A robust metal–organic open framework, namely, [Ni(cyclam)(bpydc)]·5H2O (1), is reported, which is constructed of linear coordination polymer chains made of the nickel– macrocyclic complex, which retains their crystallinity during the reversible desorption/adsorption of guest molecules.
Abstract: Metal–organic open-framework solids have been the focus of research interest because of their potential applications in molecular adsorption and separation processes, ion exchange, 6] catalysis, sensor technology, and optoelectronics. They can be designed and assembled to generate cavities or channels of various sizes and shapes by appropriate choice of the building blocks. However, despite extensive studies, information on how to design and synthesize metal– organic frameworks (MOFs) with permanent porosity is still limited. 16,17] Moreover, applications of MOFs are scarce compared to zeolites. This is because 1) they often collapse when the guest molecules occupying the voids are removed, 2) they are in general thermally unstable compared with inorganic zeolites and are destroyed at high temperatures (> 200 8C) or even at low temperatures under vacuum, and 3) they are often soluble in solvents and dissociate into their building blocks. 4, 13–15] Porous materials that retain their crystallinity during the reversible desorption/adsorption of guest molecules could be relevant as sensing devices. Here we report a robust metal–organic open framework, namely, [Ni(cyclam)(bpydc)]·5H2O (1), which is constructed of linear coordination polymer chains made of the nickel– macrocyclic complex [Ni(cyclam)](ClO4)2 (cyclam= 1,4,8,11tetraazacyclotetradecane) and 2,2’-bipyridyl-5,5’-dicarboxylate (bpydc ). Open framework 1 shows a reversible type I
370 citations
328 citations
TL;DR: 3 subset 4Me(2)CO shows amorphous (nonporous)-to-crystal (porous) structural rearrangement in the Me( 2)CO adsorption and desorption process, where the framework of the 2-D motif is maintained.
Abstract: Flexible porous coordination polymers containing amide groups as a function origin have been synthesized and categorized as “Coordination Polymer with Amide Groups”. Bispyridyl ligands with a spacer of amide group afford two-dimensional (2-D) motifs with a deformed square grid, resulting in three-dimensional (3-D) frameworks of [Co(NO3)2(3-pna)2]n (1), [Co(Br)2(3-pna)2]n (2), and {[Co(NCS)2(4-peia)2]·4Me2CO}n (3 ⊃ 4Me2CO) (3-pna = N-3-pyridylnicotinamide, 4-peia = N-(2-pyridin-4-yl-ethyl)-isonicotinamide), where the 2-D motifs are bound by complementary hydrogen bond between the amide groups. In the case of the 3 ⊃ 4Me2CO, the amide groups form a contrivance for a dynamic porous framework because of their relevant position and orientation in the mutual nearest neighboring motifs. Consequently, 3 ⊃ 4Me2CO shows amorphous (nonporous)-to-crystal (porous) structural rearrangement in the Me2CO adsorption and desorption process, where the framework of the 2-D motif is maintained. The adsorption isotherm has thr...
273 citations
TL;DR: This crystal transformation provides a new pore structure that is well suited for benzene molecules, and is described as a "shape-responsive fitting" transformation, which gives rise to a new guideline.
Abstract: In situ synchrotron X-ray powder diffraction patterns of porous coordination polymers {[Cu2(pzdc)2(bpy)]·G} have been measured (pzdc = pyrazine-2,3-dicarboxylate, bpy = 4,4‘-bipyridine) (where G = H2O for CPL-2 ⊃ H2O, G = benzene for CPL-2 ⊃ benzene, and G = void for the apohost). The structures of apohost and CPL-2 ⊃ benzene were determined from Rietveld analysis. Adsorption of benzene in the channels induced a remarkable contraction in the crystal (b axis; 6.8%, volume; 4.9%), although the channels were occupied by the benzene molecules. This crystal transformation provides a new pore structure that is well suited for benzene molecules, and we denote it as a “shape-responsive fitting” transformation. This type of pore gives rise to a new guideline: frameworks can be composed of flexible motifs that are linked via strong bond and/or stiff motifs that are connected via weaker bonds.
262 citations
223 citations
TL;DR: In this article, a 2D bilayered ferromagnetic coordination polymer, generated by lower-temperature hydrothermal reactions of cobalt(II) salt with the 3,4-pyridinedicarboxylate dianion, was controlled to transform into a 3D magnetic coordination network with Co3(OH)2 ferrimagnetic chains at a higher temperature.
212 citations
209 citations
TL;DR: In this article, a new series of microporous materials containing infinite chains of mononuclear metal (Cu, Zn, Ni, pyridine unit bridged by dicarboxylates, copper(II) terephthalate-pyridine, [CuII(OOCC6H4COO)(C5H5N)2(H2O)]
204 citations
TL;DR: All of these complexes were studied by (1)H NMR spectroscopy, and complexes 3-9 were additionally characterized by X-ray crystallography.
Abstract: Reaction of 1,3-bis(2-pyridinylmethyl)-1H-imidazolium tetrafluoroborate, [H(pyCH2)2im]BF4, with silver oxide in dichloromethane readily yields [Ag((pyCH2)2im)2]BF4, 1·BF4 1·BF4 is converted to the analogous Au(I)-containing species, [Au((pyCH2)2im)2]BF4, 3, by a simple carbene transfer reaction in dichloromethane Further treatment with two equivalents of AgBF4 produces the trimetallic species [AuAg2((pyCH2)2im)2(NCCH3)2](BF4)3, 4, which contains two silver ions each coordinated to the pyridine moieties on one carbene ligand and to an acetonitrile molecule in a T-shaped fashion Monometallic [Ag((py)2im)2]BF4, 5, and [Au((py)2im)2]BF4, 6, are made analogously to 1·BF4 and 3 starting from 1,3-bis(2-pyridyl)-imidazol-2-ylidene tetrafluoroborate, [H(py)2im]BF4 Addition of excess AgBF4 to 6 yields the helical mixed-metal polymer, {[AuAg((py)2im)2(NCCH3)](BF4)2}n, 7 which contains an extended Au(I)−Ag(I) chain with short metal−metal separations of 28359(4) and 29042(4) A Colorless, monometallic [Hg((pyCH2
190 citations
TL;DR: A bent-shaped bipyridine ligand containing a dendritic aliphatic side chain has been synthesized as a ligand and complexed with silver ion through a self-assembling process to form supramolecular structures that differ significantly as a function of the counteranion size in the solid state.
Abstract: A bent-shaped bipyridine ligand containing a dendritic aliphatic side chain has been synthesized as a ligand and complexed with silver ion through a self-assembling process. The resulting complexes were observed to self-assemble into supramolecular structures that differ significantly as a function of the counteranion size in the solid state, as confirmed by 1-D and 2-D X-ray diffraction experiments. The secondary structure of a cationic coordination chain appears to be dependent on the size of the counteranion. As the size of anion increases, the secondary structure of the coordination chain changes, from a helical chain, via a dimeric cycle, to a zigzag chain in the solid state. Interestingly, dilute solutions of the complexes exhibiting a columnar structure in polar solvents undergo spontaneous gelation and the resulting gels display a significant Cotton effect in the chromophore of the aromatic unit. These results represent a significant example that small variation in the anion size can provide a useful strategy to manipulate the secondary structure of linear chain and thereby solid-state supramolecular structure.
TL;DR: Pyrazine-2,3,5,6-tetracarboxylic acid reacts with Cu(NO(3)x6H(2)O in 1:2 molar ratio in the presence of pyridine (py) vapor to form blue crystals of a coordination polymer that presents a new mode of association of water molecules not predicted theoretically or found experimentally.
Abstract: Pyrazine-2,3,5,6-tetracarboxylic acid (pytcH4) reacts with Cu(NO3)2·6H2O in 1:2 molar ratio in the presence of pyridine (py) vapor to form blue crystals of a coordination polymer with the empirical formula {Cu2.5(pytc)(py)8(NO3-)·10H2O}n (1). Four such polymeric chains gather around a hexadecameric water cluster to form an overall 3D metal−organic framework structure. Once the water molecules are removed, the 3D structure breaks down. It presents a new mode of association of water molecules not predicted theoretically or found experimentally.
TL;DR: In this article, the ultrasonic cleavage of high-molecular-weight linear coordination polymers of phosphane telechelic polytetrahydrofuran and palladium dichloride in dilute solution is a reversible process.
Abstract: Breaking up and making up: The ultrasonic cleavage of high-molecular-weight linear coordination polymers of phosphane telechelic polytetrahydrofuran and palladium dichloride in dilute solution is a reversible process (see picture). Sonication for 1 h led to a decrease in the weight-averaged molecular weight of the polymer from 1.7×105 to 1.0×105 g mol−1. Upon leaving the sample to stand for 24 h, the original molecular weight was completely restored.
TL;DR: In this paper, a photoluminescent three-dimensional coordination polymer containing two types of cavities is prepared by the covalent linkage of 2D bilayer motif with linear connecting ligand.
TL;DR: The scaling of the elastic modulus, relaxation time, and zero-shear viscosity with concentration are in good agreement with the predictions of Cates' model that describes the dynamics of linear equilibrium polymers.
Abstract: The rheology of reversible coordination polymer networks in aqueous solution is studied. The polymers are formed by neodymium(III) ions and bifunctional ligands, consisting of two pyridine-2,6-dicarboxylate groups connected at the 4-positions by an ethylene oxide spacer. Neodymium(III) ions can bind three of these terdendate ligand groups. At high concentrations, the polymer networks yield viscoelastic materials, which can be described with the Maxwell model. The scaling of the elastic modulus, relaxation time, and zero-shear viscosity with concentration are in good agreement with the predictions of Cates' model that describes the dynamics of linear equilibrium polymers. This indicates that the networks have only few cross-links and can be described as linear equilibrium polymers. The gels are also thermo-reversible. At high temperatures, fast relaxation was found, resulting in liquidlike behavior. Upon cooling, the viscoelastic properties returned immediately. From the temperature dependence of the relaxation time, an activation energy of 49 kJ/mol was determined for the breaking and reptation of the polymers.
TL;DR: The crystal structure of 2 reveals that each Cu(II) is coordinated by two nitrogen atoms from different BPP ligands and two 3-thiopheneacetate groups within a distorted square planar geometry in a trans-[N, N, O, O] arrangement.
Abstract: From the reaction between a dinuclear paddle-wheel carboxylate, namely [Cu2mu-(O2CCH2C4H3S)4] (1), and the flexible ligand 1,3-bis(4-pyridyl)propane (BPP) a neutral 2-D coordination polymer [[Cu2(O2CCH2C4H3S)4mu-(BPP)2]]n (2) was obtained. Compounds 1 and 2 were characterized by means of elemental analysis, thermal analysis (TG/DSC), vibrational spectroscopy, and electron paramagnetic resonance (EPR). The crystal structure of 2 reveals that each Cu(II) is coordinated by two nitrogen atoms from different BPP ligands and two 3-thiopheneacetate groups within a distorted square planar geometry in a trans-[N, N, O, O] arrangement. The BPP ligand adopts a TG conformation bridging two copper centers giving rise to a 1-D sinusoidal polymeric chain along the crystallographic c axis. Adjacent 1-D chains are extended into a 2-D coordination network through pairs of monatomic carboxylate bridges in direction of the b axis. This bridging mode affords centrosymmetric dimeric units Cu2O2, and therefore, the copper ions are involved in a CuN2O2O' chromophore displaying a (4 + 1) square pyramidal coordination in the resultant 2-D polymeric network. The polycrystalline X-band EPR spectrum of 2 at room temperature is characteristic of a triplet state with nonnegligible zero-field splitting in agreement with the crystal structure. Crystal data for 2: monoclinic, space group P2(1)/c, a = 9.4253(10) A, b = 10.9373(10) A, c = 23.6378(10) A, beta = 98.733(4) degrees, Z = 2.
TL;DR: It is suggested that in the formation of 1, the solvent-coordinated intermediate species would be generated first and its trans coordination configuration should define the placement orientation of L(1) in the resulting polymer of 1.
Abstract: The assembly of Co(NCS)(2) with 1-methyl-1'-(3-pyridyl)-2-(4-pyridyl)ethene (L(1)) exhibits a novel supramolecular isomerism of [Co(L(1))(2)(NCS)(2)](infinity) caused by different placement orientation of L(1) around metal centers. The reaction in MeOH/H(2)O and EtOH/H(2)O resulted in a double chain structure of 1, and that in EtOH/CH(3)NO(2) led to an open framework structure of 2. The reaction in MeOH/CH(3)NO(2) solvent system concomitantly afforded 1 and 2. The assemblies of 1-(3-pyridyl)-2-(4-pyrimidyl)ethene (L(2)) with Co(NCS)(2) created the water-coordinated complexes of Co(L(2))(2)(H(2)O)(2)(NCS)(2) (3 and 4), an MeOH coordinated complex of Co(L(2))(2)(H(2)O)(2)(NCS)(2) (5), and an open framework coordination polymer of [Co(L(1))(2)(NCS)(2)](infinity) (6) depending on the reaction solvent system. From these observations, it is suggested that in the formation of 1, the solvent-coordinated intermediate species would be generated first and its trans coordination configuration should define the placement orientation of L(1) in the resulting polymer of 1. On the other hand, it is presumed that the solvent-coordinated intermediate would not be produced during the formation of 2 due to the weaker coordination ability of EtOH and CH(3)NO(2) molecules. The open framework coordination polymers of 2 and 6 are converted in the solid state into the isomeric coordination polymer of 1 and hydrogen bonded network structure of 3, respectively.
TL;DR: This work has presented what is to their knowledge the first example of a metal-organic coordination polymer that incorporates the sextuplet phenyl embrace as a supramolecular synthon.
TL;DR: Pyridine-2,4,6-tricarboxylic acid (ptcH(3) readily reacts with a Zn(II) salt at room temperature to form different products depending upon the presence or absence of pyridine in the reaction mixture.
Abstract: Pyridine-2,4,6-tricarboxylic acid (ptcH3) readily reacts with a Zn(II) salt at room temperature to form different products depending upon the presence or absence of pyridine in the reaction mixture. In the presence of pyridine, the ligand breaks to form infinitely zigzag coordination polymers with the empirical formula {Zn(Ox)(py)2}n (Ox = oxalate, py = pyridine). The backbone is formed from Zn(II)−oxalate where two pyridine molecules are coordinated to each Zn(II) ion giving it hexacoordination. The orientation of the bound pyridines is slightly different when Zn(II)−nitrate is used compared to that when Zn(II)−sulfate (or acetate) salt is used. In absence of pyridine, the ligand remains intact and forms a mixture of a carboxylate-bridged coordination polymer and a discrete carboxylate-bridged 12-membered metallomacrocycle.
TL;DR: A previously elusive "molecular capsule" and various other structural motifs incorporating p-sulfonatocalix[4]arene are accessible by controlling the pH and by varying the stoichiometry of the calixarene relative to potential guest molecules and trivalent metal ions.
Abstract: A previously elusive “molecular capsule” and various other structural motifs incorporating p-sulfonatocalix[4]arene are accessible by controlling the pH and by varying the stoichiometry of the calixarene relative to potential guest molecules and trivalent metal ions. The “molecular capsule” has monoprotonated 1-aza-18-crown-6 shrouded by two calixarenes, which hydrogen bond to aquated lanthanide ions. In contrast, the presence of 1-aza-15-crown-5 forms a complex devoid of the crown ether, with lanthanide ions directly bound to sulfonate groups. Also reported are a coordination polymer incorporating monoprotonated 1,4-diazabicyclo[2.2.2]octane in the cavity of one calixarene which forms chelate rings to lanthanide ions and the structure of a capsule with 4,13-diaza-18-crown-6 surrounded by two calixarenes which hydrogen bond to homoleptic aquated trivalent gallium ions.
TL;DR: X-ray analysis shows a covalent 3D network in which the copper(II) centers are bridged by tridentate mu-N3,N7,N9 adeninate ligands.
Abstract: The first 3D coordination polymer containing a nucleobase as a bridging ligand, {[Cu2(μ-ade)4(H2O)2][Cu(ox)(H2O)]2·∼14H2O}n (1), has been synthesized by reaction of adenine (Hade) with a basic solution of K2[Cu(ox)2]·2H2O (ox = oxalato dianion). Compound 1 crystallizes in the trigonal space group R3 with a = b = 31.350(1) A, c = 14.285(1) A, V = 12158.7(10) A3, and Z = 9. X-ray analysis shows a covalent 3D network in which the copper(II) centers are bridged by tridentate μ-N3,N7,N9 adeninate ligands. The compound has relatively large, nanometer-sized tubes associated with the self-assembly process directed solely by metal−ligand interactions. The covalent 3D framework remains intact upon removal of the guest water molecules trapped in the nanotubes. Magnetic measurements indicate an overall antiferromagnetic behavior of the compound.
TL;DR: Under hydrothermal (solvothermal) reaction conditions chiral compounds 1, 2, and 3 and one acentric compound 4 were obtained by the reaction of Zn (2+) or Cd(2+) with racemic 3-(3-pyridyl)-3-aminopropionic acid (rac-HPAPA).
Abstract: Under hydrothermal (solvothermal) reaction conditions chiral compounds 1, 2, and 3 and one acentric compound 4 were obtained by the reaction of Zn 2 + or Cd 2 + with racemic 3-(3-pyridyl)-3-aminopropionic acid (rac-HPAPA). Compounds 1 and 2 crystallized in chiral space group P2 1 2 1 2 1 . At 105°C, racemic 3-pyridyl-3-aminopropionic acid (rac-HPAPA) reacted with Zn(ClO 4 ) 2 .6H 2 O and dehydrogenated in situ to form the first chiral coordination polymer [Zn{(E)-3-C 5 H 4 N-C(NH 2 )=CH-COO)]ClO 4 (1) with a β-dehydroamino acid. Beyond 120°C, the reaction of rac-HPAPA with Zn(ClO 4 ) 2 .6H 2 O deaminates in situ to form chiral coordination polymer [Zn{(E)-3-C 5 H 4 N-CH=CH-COO}(OH)] (2). At relatively low temperatures (70°C), the solvothermal reaction of Zn(NO 3 ) 2 6H 2 O with rac-HPAPA in methanol does not lead to any change in the ligand and results in the formation of a chiral (P2 1 2 1 2 1 ) coordination polymer [Zn(papa)(NO 3 )] (3). The same reaction of Cd(ClO 4 ) 2 .6H 2 O with HPAPA also does not lead to any change in ligand and results in the formation of noncentric (Cc) coordination polymer [Cd(papa)(Hpapa)]ClO 4 .H 2 O (4). The network topology of both 1 and 3 is 10,3a, while 2 has a diamond-oid-like (KDP-like, KDP=potassium dideuterophosphate) network. Particularly interesting from a topological perspective is that 4 has an unprecedented three-dimensional network. Compounds 1, 2, 3, and 4 are all second harmonic generation (SHG) active with 1 exhibiting the strongest response, while only 4 also displays good ferroelectric properties.
TL;DR: In this paper, the preparation and crystal structures of four MnII carboxylate complexes containing 2-pyridinealdoxime, (py)CHNOH, are reported.
TL;DR: Six new complexes of silver(I) complexes have extended supramolecular structures based on noncovalent interactions supported by the counterions and the functional groups designed into the ligands.
Abstract: The new ligands 1,1,4,4-tetra(1-pyrazolyl)butane [CH(pz)(2)(CH(2))(2)CH(pz)(2), L2] and 1,1,5,5-tetra(1-pyrazolyl)pentane [CH(pz)(2)(CH(2))(3)CH(pz)(2), L3] have been prepared to determine the structural changes in silver(I) complexes, if any, that accompany the lengthening of the spacer group between two linked bis(pyrazolyl)methane units. Silver(I) complexes of both ligands with BF(4)(-) and SO(3)CF(3)(-) as the counterion have the formula [Ag(2)(micro-L)(2)](counterion)(2). These complexes have a cyclic dimeric structure in the solid state previously observed with the shorter linked ligand CH(pz)(2)CH(2)CH(pz)(2). Similar chemistry starting with AgNO(3) for L2 yields a complex of the empirical formula [Ag(2)[micro-CH(pz)(2)(CH(2))(2)CH(pz)(2)](3)](NO(3))(2) that retains the cyclic dimeric structure, but bonding of an additional ligand creates a coordination polymer of the cyclic dimers. In contrast, coordination of the nitrate counterion to silver in the complex of L3 leads to the formation of the coordination polymer of the empirical formula [Ag(micro-CH(pz)(2)(CH(2))(3)CH(pz)(2))]NO(3). All six new complexes have extended supramolecular structures based on noncovalent interactions supported by the counterions and the functional groups designed into the ligands.
TL;DR: The hydrothermal reaction of mellitic acid, 4,4'-bipydine, and Cu(CH(3)COO)(2).H(2)O gave rise to a novel 3D supramolecular architecture interpenetrated by three types of coordination polymer motifs.
Abstract: The hydrothermal reaction of mellitic acid, 4,4'-bipydine, and Cu(CH(3)COO)(2).H(2)O gave rise to a novel 3D supramolecular architecture interpenetrated by three types of coordination polymer motifs. Two independent [[Cu(2)(mellitate)(4,4'-bpy)(H(2)O)(2)](2)(-)] 3D polymers incorporating helical substructures were interwoven into a 3D network with double-stranded helical tubes that host 1D linear polymers [Cu(4,4'-bpy)(H(2)O)(4)](2+)](n).
TL;DR: Reversible construction of a nanoporous framework from a nonporous framework has been found in the zinc(II) coordination polymer with 4,4'-oxybis(benzoate) (oba).
Abstract: Reversible construction of a nanoporous framework from a nonporous framework has been found in the zinc(II) coordination polymer with 4,4'-oxybis(benzoate) (oba). [Zn(2)(oba)(2)(dmf)(2)].2DMF (1), which has 1 nm scale channels, transforms to the nonporous coordination polymer [Zn(oba)(H(2)O)] (2) with the loss of the open framework. Compound 2 on treatment with DMF reversibly yields nanoporous compound 1.
TL;DR: In this article, four succinato-bridged complexes of copper(II) have been synthesized and the coligand bpy and phen in these complexes show face-to-face (in 1, 2, 3, 4) or edge-to face (in 4) interactions forming the multidimensional supramolecular architectures.
Abstract: Four succinato-bridged complexes of copper(II) have been synthesized. Complex 1, [Cu2(μ-OH2)2L(bpy)2(NO3)2]n and 2, [Cu2(μ-OH2)2L(phen)2(NO3)2]n
(bpy = 2,2′-bipyridine; phen = 1,10-phenanthroline and LH2
= succinic acid) exhibit 1D coordination polymer structures where both the nitrate ions are directly linked to the copper(II) producing synthons in a 2D sheet. A novel 2D grid-like network, {[Cu4L2(bpy)4(H2O)2](ClO4)4(H2O)}n3, is obtained upon changing the nitrate by perchlorate anion in complex 1, where the channels are occupied by the anions. On changing the nitrate by tetrafluoroborate anion in complex 2, a novel octanuclear complex, [Cu8L4(phen)12](BF4)8·8H2O 4, is isolated. The coligand bpy and phen in these complexes show face-to-face (in 1, 2, 3, 4) or edge-to-face (in 4)
π–π interactions forming the multidimensional supramolecular architectures. Interestingly, the appearance of edge-to-face π–π interactions in complex 4 facilitates the formation of discrete octanuclear entities. Variable-temperature (300–2 K) magnetic measurements of complexes have been done. Complexes 1 and 2 show very weak antiferromagnetic (OOC–CH2–CH2–COO) and ferromagnetic coupling (μ-H2O). Complex 3 also shows antiferromagnetic (syn–syn
μ-OCO), and ferromagnetic coupling (μ-O of the -COO group). Complex 4 with two types (syn–syn and syn–anti) of binding modes of the carboxylate group shows strong antiferromagnetic interaction.
TL;DR: In this paper, the first mixed mixed cyano-azide bridged compound with metamagnetism below 218 K, a temperature much higher than that of the crossed double chain [Cr(phen)(CN)4]2 [Mn(H2O)2]·4 H2O (1) based on the same building block.
TL;DR: In this article, the deprotonated N-(2-hydroxybenzyl)-L-valine ligand (Sval) with Cu(II) salts was shown to give a 2D hydrogen-bonded coordination polymer in the solid state, which has a 1D coordination polymeric structure cross-linked by strong hydrogen bonds.
Abstract: The reaction of the deprotonated N-(2-hydroxybenzyl)-L-valine ligand (Sval) with Cu(II) salts afforded [Cu 2 (Sval) 2 (H 2 O) 3 ] n , 1, which has a 1D coordination polymeric structure cross-linked by strong hydrogen bonds to give 2D hydrogen-bonded coordination polymer in the solid state. Compound 1 can lose all the water molecules bonded to Cu(II) below 110°C. However, recrystallization from aqueous solution of anhydrous 1 gave a supramolecular isomer, [Cu 2 (Sval) 2 (H 2 O)] n .2nH 2 O, 2. Interestingly, the thermal dehydration behavior of 2 is very similar to that of 1. Pseudo-supramolecular isomeric compounds of [Cu 2 (Sval) 2 (H 2 O)] n .0.5nC 3 H 7 OH, 3, and [Cu 4 (Sval) 4 (H 2 O) 2 (C 4 H 9 OH)] n .nC 4 H 9 OH, 4, were obtained when anhydrous 1 was recrystallized from 2-proponal and 1-butanol, respectively.
TL;DR: A series of selectively fluorinated and non-fluorinated rigid rods based on the 4-pyridylethynyl group, namely 1,4-bis(4′-Pyridylthynynyl)benzene (1a), 1, 4-bis (4′)-tetrafluorobenzene, 1b, 1c, 2, 3a and 3b were prepared in good yields using Pd/Cu-catalysed Sonogashira cross-coupling reactions and/or lithium chemistry involving nucle
Abstract: A series of selectively fluorinated and non-fluorinated rigid rods based on the 4-pyridylethynyl group, namely 1,4-bis(4′-pyridylethynyl)benzene (1a), 1,4-bis(4′-pyridylethynyl)tetrafluorobenzene (1b), 1,4-bis(2′,3′,5′,6′-tetrafluoropyridylethynyl)benzene (1c), 1,4-bis(2′,3′,5′,6′-tetrafluoropyridylethynyl)tetrafluorobenzene (1d), 9,10-bis(4′-pyridylethynyl)anthracene (2), 4-(pentafluorophenylethynyl)pyridine (3a) and 4-(phenylethynyl)tetrafluoropyridine (3b) were prepared in good yields using Pd/Cu-catalysed Sonogashira cross-coupling reactions and/or lithium chemistry involving nucleophilic aromatic substitution. UV-Vis absorption and fluorescence spectra for 1a–d and 2 are reported. The X-ray crystal structures of 1b, 1c, 2, 3a and 3b show a variety of packing motifs, none of which involve arene–perfluoroarene stacking. The phase behaviour of 1a–1c has been studied by differential thermal analysis and transmitted polarised light microscopy. Compound 1b exhibits an ordered phase between 227.6 and 272.5 °C which is either hexatic B or crystal B. A 1 ∶ 1 complex (4) between 1b and Zn(NO3)2 has been prepared; its crystal structure consists of zig-zag polymer chains held together by hydrogen bonds.