Biphenyldicarboxylic Acid Research Articles

In Situ Observation of a Deprotonation-Driven Phase Transformation: 4,4′-Biphenyldicarboxylic Acid on Au(111)

We have studied the growth of 4,4′-biphenyldicarboxylic acid (BDA) domains on Au(111) by means of low-energy electron microscopy (LEEM) and selective area low-energy electron diffraction (μLEED). Between 300 and 400 K, BDA forms three different 2-D crystalline phases, which are attributed to different degrees of deprotonation. At room temperature, BDA condenses in needle-shaped domains (α-phase) with the carboxylic acid–dimer as the main molecular bonding motif. Upon annealing from room temperature to above about 330 K, the needle-shaped domains change irreversibly into more compact ones. This remarkable feature is attributed to a partial deprotonation of the carboxylic end groups and thus breaking of the dimers, which allows the molecules to establish hydrogen bonds with adjacent molecules by a slight rotation (β-phase). A third phase is formed upon direct adsorption of BDA at substrate temperatures above 330 K. In this γ-phase the deprotonated BDA molecules form an open 2-D metal–organic coordination network, probably by incorporation of thermally excited Au adatoms.

Formation and decay of a compressed phase of 4,4′-biphenyldicarboxylic acid on Cu(001)

The molecular arrangement of 4,4'-biphenyldicarboxylic acid (BDA) on Cu(001) has been studied at high coverage and relatively high temperature (~400 K) using Low Energy Electron Microscopy, LEEM, and selected area diffraction, μLEED. Next to the previously reported c(8 × 8) structure, we also observe a compressed phase with a [structure: see text] superstructure in matrix notation. All four equivalent (rotational and mirror) domains are equally populated. Both the c(8 × 8) and the compressed phase are confined to the first layer and the latter has a 14% higher density compared to the c(8 × 8) phase. Remarkably, this compressed phase is stable only during deposition and decays after interruption of the deposition. Apparently, the density of physisorbed admolecules on top of the c(8 × 8) layer has to be above a relevant threshold to allow the formation of the compressed phase.

Novel metal(ii) coordination polymers based on N,N′-bis-(4-pyridyl)phthalamide as supercapacitor electrode materials in an aqueous electrolyte

Based on the redox-active L (N,N'-bis-(4-pyridyl)phthalamide) ligand, two porous MOFs formulated as Zn(6)(BPC)(6)(L)(3)·9DMF (H(2)BPC = 4,4'-biphenyldicarboxylic acid) (1) and Cd(2)(TDC)(2)(L)(2)·4H(2)O (H(2)TDC = 2,5-thiophenedicarboxylic acid) (2) were synthesized and structurally characterized by single-crystal X-ray diffractions. Complex 1 features a uninodal 5-connected 3-fold interpenetrated 3D framework with {4(6).6(4)}-bnn hexagonal BN topology. Complex 2 displays a uninodal 6-connected 2-fold interpenetrated 3D framework with {4(12).6(3)}-pcu topology. When complexes 1 and 2 are used as supercapacitor electrode materials, they can provide a large voltage window as high as 2.6 V in an aqueous electrolyte, and their specific capacitances are much more than the value for the bare carbon glassy electrode. It is observed that the more the current density, the less the specific capacitance for the two kinds of supercapacitor electrode materials. The two complexes show different thermal stabilities, UV absorption and photoluminescence properties.

Auxiliary ligand-directed synthesis of four novel functional supramolecular metal–organic frameworks from 1-D chains to 3-D architectures

Abstract Four novel functional supramolecular metal–organic coordination polymers, [Cd2Cl3(IP)2(NIPH)2](1), [Zn2(IP)2(μ2-SO4)2(NIPH)2]·2H2O(2), [Cd(IP)2(BPDC)](3), [Zn2(IP)2(NDC)2](4) (IP = 1-H-imidazo[4,5-f][1,10]-phenanthroline, H2NIPH = 5-nitro-isophthalic acid, H2BPDC = 4,4′-biphenyldicarboxylic acid, H2NDC = 2,6-naphthalenedicarboxylic acid), have been obtained through three types of dicarboxylate linkers. All the four compounds are extended into a 3-D supramolecular framework by hydrogen bonds or weak aromatic interactions. The different structures demonstrate the effect of the dicarboxylate ligands on the formation of such coordination architectures. Compound 1 is a 1-D double-stranded loop-like chain with repeated [Cd4(Cl)4]4 + units connected by H2NIPH ligands. In compound 2, there are two indie 1D zigzag chains jointed by sulfate anions with μ2-bridging mode. With different metal centers, compounds 1 and 2 hold different crystal structures. With different auxiliary dicarboxylate ligands, compounds 3 and 4 exhibit disparate 1D chains. The fluorescence property and thermal stability of all complexes are also investigated.

Construction of four new coordination polymers based on sulfone-4,4′-biphenyldicarboxylic acid ligand: Synthesis, structures and properties

Four new metal–organic coordination polymers, [Cd2(sbpdc)2(bpy)] (1), [Cd(sbpdc)(bpp)1/2] (2), [Co(sbpdc)(bpy)] (3) and [Co(sbpdc)(bpp)(H2O)] (4) (H2sbpdc = sulfone-4,4′-biphenyldicarboxylic acid, bpy = 4,4′-bipyridine, bpp = 1,3-bis(4-pyridyl)propane) have been synthesized under solvothermal conditions and characterized by single-crystal X-ray diffraction, elemental analysis and IR spectra. Compound 1 displays a 3D 6-connected twofold interpenetrated net with pcu topology, while 2 contains 1D infinite Cd-O-Cd chains. Compound 3 is a new 3D binodal network with the point symbol of (63) (67 ⋅ 83), whereas compound 4 has a 1D double chain. Moreover, the PXRD, TGA, luminescent and magnetic property were also investigated.

Influence of sterically non-hindering methyl groups on adsorption properties of two classical zinc and copper MOF types

Abstract The metal-organic frameworks (three-dimensional porous coordination polymers) [Zn 4 O(Me 4 BPDC) 3 ] × 9 DMF, 2 · 9 DMF and [Cu 2 (Me 4 BPDC) 2 ] × 9 DMF, 3 · 9 DMF are representatives of the classical Zn-IRMOF series and Cu paddle-wheel complexes with H 2 Me 4 BPDC = 2,2′,6,6′-tetramethyl-4,4′-biphenyldicarboxylic acid, 1 . The dicarboxylate linker of 1 is a representative of the non-planar biphenyl ligand family, known as an efficient scaffold for chiral molecules. There is a 90° twist angle between the phenyl rings in 1 , dictated by the methyl groups, which leads to assembly of doubly interpenetrated pcu-a (in 2 ) and nbo-a (in 3 ) nets under low temperature solvothermal conditions in dimethylformamide (DMF). Activation by degassing (to yield 2 ), exchange with methanol or tetrahydrofuran and subsequent evacuation at elevated temperatures (to yield 3 I ) gave materials with BET surface areas of 1735 m 2 /g ( 2 ) and 1041 m 2 /g ( 3 I ). Adsorbed quantities of H 2 were 1.26 wt% ( 2 ) and 1.02 wt% ( 3 I ) (77 K, 1 bar), CO 2 30.8 cm 3 /g ( 2 ) and 50 cm 3 /g ( 3 I ) (273 K, 1 bar) and CH 4 12.9 cm 3 /g ( 2 ) and 11.4 cm 3 /g ( 3 I ) (273 K, 1 bar). The H 2 and CO 2 sorption values for 2 are similar to those of MOF-5 (IRMOF-1) with its almost doubled BET surface area. An increase is found concerning the adsorbed amounts of N 2 , H 2 , and CO 2 for 3 I compared to related doubly interpenetrated nbo-a -type MOF-601, MOF-602, MOF-603 ([Cu 2 L 2 ] with L = 2,2′-R 2 -4,4′-biphenyldicarboxylate, R = CN, Me, I, respectively).

Molecular self-assembly on an insulating surface: interplay between substrate templating and intermolecular interactions

We report on molecular self-assembly of biphenyl-4,4′-dicarboxylic acid (BPDCA) on under ultra-high vacuum conditions. Two-dimensional, ordered islands are obtained upon deposition at room temperature, coexisting with a streaky structure that is ascribed to individual, mobile molecules forming a two-dimensional gas-like phase. High-resolution non-contact atomic force microscopy (NC-AFM) images of the molecular islands reveal an ordered inner structure that is dominated by rows of molecules aligned side by side running along the crystallographic direction. A detailed analysis of these rows exhibits inter-row distances that are multiples of the calcite unit cell dimension along the direction, clearly demonstrating the templating effect of the substrate. Our results indicate that an excellent size match of the molecular structure with respect to the underlying substrate results in an increased binding of the BPDCA molecules to the surface. In between the rows, a different molecular structure is coexisting with the molecules aligning head to tail. This structure is explained by intermolecular hydrogen bond formation very similar to the BPDCA bulk structure. The coexistence of the bulk-like structure with the row structure suggests a close balance of intermolecular and molecule–surface interactions to be responsible for the observed structure formation.

New MOFs based on the unexplored linker 4,4′-dimethoxy-3,3′-biphenyldicarboxylic acid

New MOFs based on the unexplored linker 4,4′-dimethoxy-3,3′-biphenyldicarboxylic acid

Synthesis, structures, and luminescent properties of four new 3D lanthanide metal–organic frameworks with fluorescent whitener, 4,4′-biphenyldicarboxylate and 1,10-phenanthroline

Abstract A new series of lanthanide metal–organic frameworks, namely, [Ln (L) (bpdc)0.5 (phen)]∞ (Ln = Eu (1), Gd (2), Tb (3), Dy (4); L = 4,4′-bis(2-sulfonatostyryl)biphenyl; bpdc = 4,4′-biphenyldicarboxylate; phen = 1,10-phenanthroline), has been synthesized hydrothermally from the self-assembly of the lanthanide ions (Ln3 +) with the fluorescent whitener disodium 4,4′-bis(2-sulfonatostyryl)biphenyl (Na2L), the 4,4′-biphenyldicarboxylic acid (H2bpdc) and 1,10-phenanthroline. All of them were characterized by IR spectroscopy, elemental analysis, thermogravimetric analysis and single-crystal X-ray diffraction. To the best of our knowledge, this is the first time to use the Na2L to synthesize LMOFs in coordination bonds binding fashion. Structural analyses reveal that all four complexes have isostructural three-dimensional (3D) net-structures. Complexes 1–4 display intriguing fluorescent properties and the photoluminescent properties of 1 were discussed in detail.

Synthesis and properties of thermotropic liquid-crystalline polyesters containing 9,10-diphenylanthracene moiety in the main chain

We synthesized thermotropic liquid-crystalline polyesters in which 9,10-diphenylanthracene moieties are incorporated into the main chain type of polyester forming the chiral smectic C (Sm C*). The polymers were prepared by the isopropyltitanate-catalyzed reaction of biphenyldicarboxylic acid and the corresponding diols, with different ratios of diol of 9,10-diphenylanthracene moiety to the alkane diols (1, 5, and 10 mol %) under nitrogen atmosphere. The polymers exhibited thermotropic liquid crystals despite the presence of a bulky diphenylanthracene moiety in the main chain. The circular dichroism spectra revealed that a Sm C* phase was formed in the polymer with 1 mol % of anthracene moiety, although only an Sm A phase was formed in the other polymers. This is the first example of a Sm C* polyester containing a diphenylanthracene moiety in the main chain. Furthermore, we measured the optical properties of the polymers and found that they exhibited very high fluorescent efficiency. The fluorescence spectra of the thin film differed from that of a CH2Cl2 solution.

Synthesis and structure of a novel blue luminescent coordination polymer possessing 3D network with mirror symmetry triple-interpenetrated sixteen-membered rings

Abstract A novel Cd(II) coordination polymer [Cd(bpdc)(H2O)]n 1 (4,4′-H2bpdc = 4,4′-biphenyldicarboxylic acid) with 3-D open frameworks has been hydrothermally synthesized by the reaction between 4,4′-biphenyldicarboxylic acid and Cd(NO3)2·4H2O. The structure of coordination polymer 1 was characterized by single-crystal X-ray diffraction analysis, IR spectroscopy and element analysis. The result of single-crystal X-ray diffraction analysis reveals that coordination polymer 1 exhibits novel 4-connected net with the point symbol of {42 · 84}. Two carboxylate ends of bpdc2− ligand link Cd(II) cations into a dinuclear cluster. Mirror symmetry triple-interpenetrated sixteen-membered rings of 12.11 A × 19.16 A form into 3-D open frameworks through connecting to the bpdc2− ligands. Coordination polymer 1 and 4,4′-H2bpdc both emit blue luminescence in DMSO solution and in the solid state, which can be attributed to ligand-centered π*→π transitions.

Phase transformations of 4,4′-biphenyldicarboxylic acid on Cu(001)

The growth and structure of $4,{4}^{\ensuremath{'}}$-biphenyldicarboxylic-acid (BDA) on Cu(001) at temperatures between 300 and 400 K was studied by low energy electron microscopy and $\ensuremath{\mu}$-LEED. First, the adsorbed BDA molecules form a disordered dilute phase. Once this phase reaches a sufficiently high density, a crystalline phase nucleates, in which the molecules form a hydrogen-bonded two-dimensional (2D) supramolecular $c(8\ifmmode\times\else\texttimes\fi{}8)$ network. By a careful analysis of the bright-field image intensity, we can measure the density in the dilute phase, which is up to 30$%$ of that in the crystalline phase. From the respective equilibrium densities at different temperatures, we determine the 2D phase diagram and extract a cohesive energy of 0.35 eV. We also analyze the island decay behavior and estimate the BDA molecule diffusion constants. Steps are found to be highly transparent for diffusing BDA molecules. In the temperature range of 362--400 K, we find chemical diffusion constants between 850--1700$\phantom{\rule{0.28em}{0ex}}{\mathrm{nm}}^{2}\phantom{\rule{0.16em}{0ex}}{\mathrm{s}}^{\ensuremath{-}1}$.

Influence of solvent on the chiral resolution of organic molecules on Au(111): EC-STM study of biphenyl dicarboxylic acid on Au(111) in an aqueous environment

Adsorption-induced chiral resolution of organic molecules is important due to its potential applications in stereo-selective catalysis. We studied the adsorption-induced chiral resolution using a model achiral molecule of 4,4′ biphenyl dicarboxylic acid (BPDA) on Au(111) in 0.1M perchloric acid (HClO4) by electrochemical scanning tunneling microscopy (EC-STM). Our experimental data showed that the BPDA molecules formed island structures with distinctive preferred orientations at the length scale of the molecular size. The molecules did not show any orientational ordering above the length scale, indicating that chiral resolution was absent in the aqueous environment. Previously, the molecules were found to have chiral resolution on Au(111) in ultra-high vacuum conditions (UHV). We calculated angle-dependent binding energy between the substrate and a BPDA molecule, the intermolecular interactions between the BPDA molecules, and their interactions with water molecules. The calculations suggest that the absence of chiral resolution in the aqueous environment originated from the decrease in the intermolecular energy of the BPDA molecules due to their hydrogen bonds with the surrounding water molecules. The strength of the hydrogen bonding between BPDA molecules was sufficient to overcome the energy barrier for chiral resolution through rotational motion in UHV, but not in an aqueous environment.

A self-assembled (H2O)20(CH3OH)4 binary cluster containing a grail-shaped hexadecameric water cluster trapped in the cavity of a metal-ligand hybrid

A discrete centrosymmetric (H2O)20(CH3OH)4 binary cluster was confined in the cavity of a metal-ligand hybrid [Ag4(bpda)2(bpp)4·14H2O·2CH3OH]n (1) (where bpp = 1,3-bis(4-pyridyl)propane and H2bpda = 2,2′-biphenyldicarboxylic acid). The novel mixed water-methanol cluster consists of one grail-shaped hexadecameric cluster, four dangling water and four hanging methanol molecules. The (H2O)16 cluster is composed of two pairs of edge-sharing (H2O)5 rings attached to one (H2O)4 core with twenty hydrogen bonds. Alternatively, the (H2O)16 cluster is structurally similar to a complicated hydrocarbon generated by undergoing [2+2] cycloaddition of 1,2,3,4,5,6-hexahydropentalene, which reveals the resemblance between water clusters and organic compounds.

Characterization and thermal‐oxidative degradation behavior of poly(ethylene terephthalate‐co‐4,4′‐bibenzoate) prepared via direct esterification technique

AbstractA series of poly(ethylene terephthalate‐co‐4,4′‐bibenzoate)s (PETBBs) were prepared via direct esterification from the monomers of terephthalic acid (TPA), 4,4′‐biphenyl dicarboxylic acid (BPDA), and ethylene glycol (EG) with different molar ratios. The chemical compositions of the obtained PETBBs, investigated by H1‐NMR, were identical with the feed ratio, and the high molecular weights of PETBBs were confirmed by GPC analysis. The glass transition, crystallization, and melting behavior of them were measured by DSC; the results indicated that, in the range of 5–25 mol% of BPDA addition, the glass transition temperature (Tg) increased almost linearly and the melting temperature (Tm) decreased with increasing content of BPDA unit. As expected, the crystallization of PETBB became difficult with increasing introduction of BPDA, explained by higher crystallization temperature and smaller crystallization enthalpy from the glassy state. This decrease of crystallization rate may be beneficial to film processing. Moreover, owing to the introduction of rigid‐rod BPDA unit, the initial and maximum thermal‐oxidative decomposition temperatures were enhanced. The kinetic analysis of the thermal‐oxidative degradation indicated that the apparent activation energies of degradation for these PETBBs became higher than that of PET. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers

Hydrothermal syntheses and characterization of three lanthanide coordination complexes constructed by 2,2′:6′,2″-terpyridine and 2,2′-biphenyldicarboxylic acid

Two 1D coordination polymers [Ln2(dpdc)3(tpy)2·H2O]n [Ln=Nd 1, Yb 2, H2dpdc=2,2′-biphenyldicarboxylic acid and tpy= 2,2′:6′,2″-terpyridine] and one dinuclear complex Er2(dpdc)2(Hdpdc)2(tpy)23 were obtained via hydrothermal reactions and determined by X-ray diffraction analysis. The crystal structure data of 1 and 2 revealed that two coordination polymers were isostructural and possessed a 1D chain framework consisting of eight-coordinated Ln(III) centers. In the asymmetric unit, the two Er(III) ions in 3 were both nine-coordinated and had similar coordination environments. The Er(III) ions were bridged by dpdc2− ligands into dinuclear structures. The complexes were also characterized by IR spectra and thermogravimetric analysis. The solid fluorescence of 1 and 3 was also investigated at room temperature.

A hybrid carboxylate-water decamer with a discrete octameric water moiety self-assembled in a 2D copper(II) coordination polymer

An octameric water moiety which consists of a chairlike water hexamer and two pendent water molecules in the 1,4-diaxial positions and shows a similar structure to the hydrocarbon (1r,4r)-1,4-dimethylcyclohexane, is unambiguously trapped in a 2D Cu(II) mixed-ligand coordination polymer, {[Cu2(bpp)2(H2O)2(bpda)2]·6H2O} n (1) (bpp = 1,3-bis(4-pyridyl)propane and H2bpda = 2,2′-biphenyldicarboxylic acid). The water octamer can be extended into a hybrid carboxylate-water decamer when carboxylic oxygen atoms from bpda2− are involved. Interestingly, the present hybrid decamer bears a similar structural topology to a butterfly (H2O)10 cluster. The reversible dehydration/hydration of 1 is determined by X-ray powder diffraction studies.

Synthesis, Structure, and Luminescent Properties of Lanthanide-Based Two-Dimensional and Three-Dimensional Metal–Organic Frameworks with 2,4′-Biphenyldicarboxylic Acid

A series of novel lanthanide coordination polymers have been successfully synthesized under hydrothermal or solvothermal conditions, namely, [Eu2(2,4′-bpdc)2(OH)(NO3)(H2O)3]n (1), [Ln(2,4′-bpdc)(1,4-bdc)0.5(DMF)-(H2O)·H2O]n [Ln = Eu (2); Ln = Pr (3); Ln = Nd (4)], [Ln(2,4′-bpdc)(DMF)2NO3]n [Ln = Eu (5); Ln = Nd (6); Ln = Gd (7)], and [Eu(2,4′-bpdc)(2,4′-Hbpdc)(H2O)]n(8), (2,4′-H2bpdc = 2,4′-biphenyldicarboxylic acid, 1,4-H2bdc = 1,4-benzenedicarboxylic acid, and DMF = N,N′-dimethylformamide). X-ray crystallographic studies reveal that 1 features a three-dimensional (3D) framework with 45 topology. 2–4, which are isostructural and synthesized by using a mixture of 2,4′-H2bpdc and 1,4-H2bdc, exhibit two-dimensional (2D) (3,4)-connected net structures. 5–7 show 2D layered structures containing double helix chains (Δ and Λ) with 44 topology. 8 possesses a 2D layered structure containing (4,6)-connected networks, which are connected by means of infinite zigzag chains linked by 2,4′-bpdc2– and 2,4′-Hbpdc– anion...

Two 3D metal–organic frameworks with different topologies, thermal stabilities and magnetic properties

Two novel 3D metal–organic frameworks, [ML]n (M = Co, 1; Mn, 2) were successfully prepared in solvothermal conditions using 3,3′-dimethoxy-4,4′-biphenyldicarboxylic acid (H2L) as the ligand. X-Ray crystallography analysis reveals that MOF 1 crystallizes in the monoclinic system, space group P21/c in contrast to MOF 2 in the tetragonal system, space group I. MOF 1 contains an elongated [CoO6] octahedron with two bound methoxy groups in the trans position, whereas MOF 2 has a compressed [MnO6] octahedron with two coordinated methoxy groups in the cis arrangement. The ligand L shows a novel bis(tridentate) bridging coordination mode. MOF 1 exhibits a 3D framework with CdSO4 (cds) topology consisting of two different nodes and good thermal stability (313 °C). MOF 2 is a doubly interpenetrated 3D α-Po framework with a higher thermal stability (368 °C). The study of magnetic properties in the temperature range of 1.8–300 K shows the occurrence of weak ferromagnetic interactions (J = 0.15 K) between the high-spin Co(II) ions in 1, but a weak antiferromagnetic coupling (J = −0.15 cm−1) between Mn(II) ions in 2 due to the syn-anti carboxylate bridge.

Selective formation of five coordination polymer particles (CPPs) and their gas sorption properties

A solvothermal approach based on In3+ and three organic linkers, 2,6-naphthalenedicarboxylic acid (H2NDC), 4,4′-biphenyldicarboxylic acid (H2BPDC) and 1,4-benzenedicarboxylic acid (H2BDC), for the synthesis of five types of coordination polymer particles (CPPs) has been demonstrated. Five CPPs are selectively fabricated in rod, lump, ribbon, sphere and sea urchin shapes depending on the organic linkers used in the reactions. The simultaneous incorporation of two different organic linkers within a CPP in a specific ratio was verified when CPPs are synthesized from a mixture of two organic linkers. The porosity and specific gas sorption properties of five CPPs are evaluated via gas sorption measurements on N2, CO2 and H2. Their porosity and specific gas sorption ability also vary depending on the linkers used in their fabrication process. While two CPPs synthesized using only one kind of organic linker are non-porous, three CPPs fabricated using the mixture of two different organic linkers are highly porous. Significant increases in the CO2 and H2 uptake abilities are also observed when CPPs are synthesized from two mixed linkers.