Bipyridine Derivatives Research Articles

Rational design of fluorescent chemosensor for Pd2+ based on the formation of cyclopalladated complex

According to the assumption that the formation of C–Pd bond becomes a cyclopalladated complex (CPC), we designed and synthesized two C–N–N pincer ligands of BODIPY appended 2,2′-bipyridine derivatives (BP and BPB). It has been confirmed that the C–Pd bond does exist and plays a crucial role in “on-off” fluorescence behavior. Based on it, a coordination-induced fluorescence quenching sensor for Pd2+ was constructed. The results indicated that BP possessed high sensitivity and specificity for Pd2+ in solution. The limit of detection (LOD) of BP is determined to be 0.97 nM within a linear range between 1.0 and 50.0 nM, meanwhile, the platinum-group ions demonstrate no interference. The bio-imaging application of BP was investigated and it exhibited a promising vitro test for fluorescent imaging of Pd2+ ions in MCF-7 cells. Meanwhile, BPB coated sensor label for Pd2+ was set up. The visible color variation was displayed under UV light with increasing concentrations of Pd2+. Briefly speaking, fluorescence probes of BP and BPB offer new approaches for Pd2+ detection in a lab and on-site test, as well as the vivo imaging. Then, with the aid of (TD)DFT calculation, the internal reason for the optical difference between the two ligands was disclosed. This concept of CPC containing a Pd–C covalent bond provides a promising perspective of coordination fluorescence sensors.

Modulating the Electromechanical Response of Bio-Inspired Amino Acid-Based Architectures through Supramolecular Co-Assembly.

Supramolecular packing dictates the physical properties of bio-inspired molecular assemblies in the solid state. Yet, modulating the stacking modes of bio-inspired supramolecular assemblies remains a challenge and the structure-property relationship is still not fully understood, which hampers the rational design of molecular structures to fabricate materials with desired properties. Herein, we present a co-assembly strategy to modulate the supramolecular packing of N-terminally capped alanine-based assemblies (Ac-Ala) by changing the amino acid chirality and mixing with a nonchiral bipyridine derivative (BPA). The co-assembly induced distinct solid-state stacking modes determined by X-ray crystallography, resulting in significantly enhanced electromechanical properties of the assembly architectures. The highest rigidity was observed after the co-assembly of racemic Ac-Ala with a bipyridine coformer (BPA/Ac-DL-Ala), which exhibited a measured Young's modulus of 38.8 GPa. Notably, BPA crystallizes in a centrosymmetric space group, a condition that is broken when co-crystallized with Ac-L-Ala and Ac-D-Ala to induce a piezoelectric response. Enantiopure co-assemblies of BPA/Ac-D-Ala and BPA/Ac-L-Ala showed density functional theory-predicted piezoelectric responses that are remarkably higher than the other assemblies due to the increased polarization of their supramolecular packing. This is the first report of a centrosymmetric-crystallizing coformer which increases the single-crystal piezoelectric response of an electrically active bio-inspired molecular assembly. The design rules that emerge from this investigation of chemically complex co-assemblies can facilitate the molecular design of high-performance functional materials comprised of bio-inspired building blocks.

Synthesis and Chemosensory Properties of New Cyanosubstituted 2,2'-Bipyridine Derivatives

A series of novel 6-oxo-1,6-dihydro-[2,2'-bipyridine]-5-carbonitriles has been synthesized and characterized. Their photophysical properties in DMSO solution and aqueous medium as well as fluorescence response to the presence of metal ions have been investigated. The obtained 4-(4-methoxyphenyl)-6-oxo-1,6-dihydro-[2,2'-bipyridine]-5-carbonitrile has been shown as a selective fluorescent "turn-ON" probe for Cd2+ ions with LoD 0.359µM, 1:1 metal-ligand ratio and binding constant of 5.2 × 104M-1.

Coronene and Bipyridine Derivatives Inducing Diversified Structural Transitions of Carboxylic Acids at the Liquid/Solid Interface

Comprehensive SummaryIn recent years, the construction of stable multicomponent assembled structures on surfaces and the exploration of the assembled mechanism have become research hotspots. In this paper, the azobenzene‐carboxylic acid called (E)‐4’,4”’‐(diazene‐1,2‐diyl) bis(([1,1’‐biphenyl]‐3,5‐dicarboxylic acid)) (H4DBBD) could self‐assemble into regular network structure at heptanoic acid/graphite via hydrogen bonding, and could be regulated into analogous kagomé network by coronene (COR) molecules. In addition, a series of bipyridine derivatives were further introduced to construct bi‐component systems with H4DBBD molecules, and successfully induced diversified structural transitions of H4DBBD on the graphite surface. Combined with scanning tunneling microscope (STM) and density functional theory (DFT) calculations, we have investigated the diversified structural transitions and analyzed the formation mechanism of the assembled systems.

Crystal Structure and Optical Properties of New Hybrid Halobismuthates of 2,2'-Bipyridinium Derivatives

Crystal Structure and Optical Properties of New Hybrid Halobismuthates of 2,2'-Bipyridinium Derivatives

Luminescent heteroleptic samarium (III) complexes: Synthesis, optical and photophysical investigation

• We have synthesized photoluminescent ternary samarium β-diketonate complexes with heterocyclic neutral ligands. • Optical and luminescent nature of red color emissive ternary samarium complexes have been studied in detail. • Photoluminescence emission spectra specify that β-diketone ligand efficiently sensitized Sm(III) ion via antenna effect. • Synthesized luminescent materials could found good significance in solid state electronics, flat panel devices and OLEDs. The octa coordinated complexes of Sm 3+ with dibenzoylmethane (DBM) having general formula [Sm(X) 3 (Y)] were synthesized in powdered form and characterized spectroscopically. Here, X is dibenzoylmethane (DBM) and Y represents respective substituted 2,2 ′ -bipyridine derivatives. The luminescent characteristics of ternary samarium complexes have been studied in detail. Upon excitation in UV range, bands at 566 nm, 606 nm, 648 nm (highly intense) and 710 nm were appeared in emission spectra of complexes attributed to characteristic transitions of Sm(III) ion. The luminescence in complexes is observed mainly because of (i) good sensitization of Sm(III) ion by auxiliary units (ii) removal of non-radiative deactivation routes by vibrations of O-H and N-H bonds. Various investigations reveal the similar structure of all the synthesized samarium complexes. The emissive properties of Sm(III) complexes show that these complexes might be utilized as good candidate in lighting and display sources.

Single-crystal X-ray diffraction analysis of arylamine-containing 2,2′-bipyridine derivatives

Single-crystal X-ray diffraction analysis of arylamine-containing 2,2′-bipyridine derivatives

Modern Methods for the Synthesis of Cyano-Substituted Bipyridine Derivatives (microreview)

Modern Methods for the Synthesis of Cyano-Substituted Bipyridine Derivatives (microreview)

Tailored nanofiltration membranes with enhanced permeability and antifouling performance towards leachate treatment

The leachate generated from the sanitary landfill or incineration poses serious environmental threats and it's difficultly disposed due to its complexity containing high concentration of organic matters and inorganic salts etc. Membrane technology stands out as a potential solution for leachate because of its beneficial advantages. Nanofiltration (NF) can reject organic compounds and separate divalent ions from mixed salts, which alleviates fouling and increases separation efficiency and flux of reverse osmosis (RO) in the popular combined processes (MBR-NF/RO) applicable for leachates. However, NF is often subject to low water permeance and membrane fouling for traditional polyamide thin film composite (PA-TFC) membranes. This work develops a high-performance NF membrane by grafting bipyridinium derivative monomer (BBD), an alternative antibacterial by interfering with the bacterial metabolism and reproduction and a hydrophilic compound endowing membrane hydrophilicity, onto PA-TFC membranes through the esterification reaction toward the leachate treatment. Resultantly, the BBD-TFC membrane achieves a reasonably high pure water permeability of 31.6 ± 2.1 L m−2 h−1 bar−1, ∼ 4 times higher than that of the pristine polyamide membrane. Notably, the resultant membrane exhibits excellent antifouling and antibacterial properties in the treatment of the leachate benefiting from the more hydrophilic surface and negative potential on BBD-TFC. Meanwhile, high rejection ratio of divalent ions and organic matter (R > 95%) was also attained companying with high separation efficiency of divalent/monovalent ions. The current work may provide an effective strategy to design high performance NF membranes for the leachate treatment or other wastewater treatment.

Fluorinated β‐diketone‐based Sm(III) complexes: spectroscopic and optoelectronic characteristics

The synthesis and characterization of a series of octa-coordinated Sm(III) complexes with 4,4,4-trifluoro-1-(2-naphthyl)-1,3-butanedione (TFNB) and 2,2'-bipyridine (Bpy) derivatives as ancillary ligand are described here. The complexes were analyzed by elemental, spectroscopic such as infrared spectroscopy, 1 H NMR, and thermogravimetric analyses. The fluorinated TFNB ligand absorbs in the range from 200 to 400 nm. The complexes show the sharp and structured Sm-based emissions in visible region upon irradiation in UV range. Excitation spectra of complexes show similarity to the absorption spectra of ligands suggesting that excitation energy is transferred from ligands to Sm(III) centre by the antenna effect. Photoluminescence emission spectra and colour parameters affirmed that the complexes show luminescence in orange-red region. These luminous Sm(III) complexes might be applied as emissive layer in organic electroluminescent devices.

Effect of substituted 2,2′-bipyridine derivatives on luminescence characteristics of green emissive terbium complexes: Spectroscopic and optical analysis

Heteroleptic ternary terbium complexes with general representation as [Tb(acac)3 L] have been prepared through single step path with acetylacetone (acac) as chromophoric and substituted 2,2ꞌ-bipyridine as auxiliary (L) moieties. The synthesized complexes are characterized systematically through elemental, spectroscopic and thermogravimetric analyses. The infra-red and proton nuclear magnetic resonance spectra are consistent with the formation of complexes. Green emission is observed for the synthesized terbium complexes in solid form and in dichloromethane (DCM) solvent due to 5D4→7F5 transition. The chromaticity parameters have estimated high color purity of the complexes and their coordinates positioned in the green region of the CIE triangle. The singlet and triplet state energy of 2,2ꞌ-bipyridine (Bpy) and 2,2′-bipyridine dihydrobromide (DBr) show the efficient sensitization of Tb3+ ion in synthesized complexes by respective ligands. The bright green emission and the values of band gap indicate the utilization of synthesized complexes in the fabrication of displays.

Designing Robust Two-Electron Storage Extended Bipyridinium Anolytes for pH-Neutral Aqueous Organic Redox Flow Batteries.

Bipyridinium derivatives represent the most extensively explored anolyte materials for pH-neutral aqueous organic redox flow batteries, and most derivatives feature two separate electron-transfer steps that cause a sharp decrease in cell voltage during discharge. Here, we propose a strategy to fulfill the concurrent two-electron electrochemical reaction by designing extended bipyridinium derivatives (exBPs) with a reduced energy difference between the lowest unoccupied molecular orbital of exBPs and the β-highest occupied molecular orbital of the singly reduced form. To demonstrate, a series of exBPs are synthesized and exhibit a single peak at redox potentials of −0.75 to −0.91 V (vs standard hydrogen electrode (SHE)), as opposed to the two peaks of most bipyridinium derivatives. Cyclic voltammetry along with diffusion-ordered spectroscopy and rotating disk electrode experiments confirm that this peak corresponds to a concurrent two-electron transfer. When examined in full-flowing cells, all exBPs demonstrate one charge/discharge plateau and two-electron storage. Continuous galvanostatic cell cycling reveals the side reactions leading to capacity fading, and we disclose the underlying mechanism by identifying the degradation products. By prohibiting the dimerization/β-elimination side reactions, we acquire a 0.5 M (1 M e–) exDMeBP/FcNCl cell with a high capacity of 22.35 Ah L–1 and a capacity retention rate of 99.95% per cycle.

Rhodium(I)-Catalyzed Regioselective C–H Alkenylation of 2,2′-Bipyridine Derivatives with Alkynes

AbstractIn this work, a Rh(I)-catalyzed C3-alkenylation of 2,2′-bipyri­dine-6-carboxamide with terminal and internal alkynes was developed, providing an efficient access to a broad range of alkenylated 2,2′-bipyridine derivatives with exclusive regioselectivity and stereoselectivity. Deuterium labeling experiments indicate that an irreversible rollover C–H activation process is involved in this reaction.

Synthesis, photophysical characteristics and geometry optimization of Tris(2-benzoylacetophenonate)europium complexes with 2, 2′-Bipyridine derivatives

A series based on octa coordinated tris(2-benzoylacetophenonate)europium complexes were synthesized with bidentate heteroaromatic auxiliary ligands. 2,2′-Bipyridine (Bpy) and its derivatives synthesized in the laboratory were used as auxiliary ligands. The structural analysis of synthesized materials was done by various spectroscopic techniques. Their photoluminescent characteristics specified the effective sensitization of trivalent europium ion via antenna effect. As an outcome of this sensitization, these complexes demonstrate good luminescence intensity, high quantum efficiency and long luminescence lifetime. The CIE chromaticity coordinates (x, y and u’, v’) were designed to indicate bright red emission. Luminescence decay time data were calculated by investigating the λem well-suited with the transition of the type 5D0→7F2. The molecular parameters of the geometrically optimized complexes were derived from the semi-empirical Sparkle/RM1 method. Theoretical Judd-Ofelt and photophysical parameters were estimated by LUMPAC software ascribed with experimental data, indicating the efficacy of this method. Furthermore, these luminous ternary europium complexes can be utilized as red light emitting material in designing flat panel displays and various optoelectronic devices.

Regulation of the Assembled Structure of a Flexible Porphyrin Derivative Containing Tetra Isophthalic Acids by Coronene or Different Pyridines.

Based on previous research, a new coassembly formed by a porphyrin derivative (IPETPP), which contains a flexible substituent of m-phthalic acid, is observed with coronene (COR) molecules at a higher concentration. Besides, a fresh IPETPP self-assembly formed at a lower concentration and another new coassembly with COR molecules are obtained. Moreover, the addition of a series of bipyridines alters the diamond arrangement of IPETPP, which enhances the stability of the two-component structures. It is unprecedented that bipyridine derivatives break intermolecular hydrogen bonds containing m-phthalic acid substituents. All the coassemblies are investigated by scanning tunneling microscopy on a highly oriented pyrolytic graphite. Combined with density functional theory, the formation mechanism of the assembled structures is revealed. These results would contribute to understanding the interfacial crystal behaviors and probably provide an efficient pathway to regulate the binary structures.

Supramolecular assemblies working as both artificial light-harvesting system and nanoreactor for efficient organic dehalogenation in aqueous environment

In this work, three artificial light-harvesting systems are constructed by a supramolecular approach in aqueous environment. The water-soluble bipyridinium derivatives (DPY1, DPY2, and DPY3) were self-assembled with cucurbit[7]uril (CB[7]) to form the host–guest DPY-CB[7] complexes, which can highly disperse in water as small nanoparticles. The excited DPY-CB[7] assemblies can transfer energy to the sulfo-rhodamine 101 (SR101) molecules at a high donor/acceptor ratio. With the help of hydrophobic cavity of CB[7], the DPY-CB[7] + SR101 systems can works as a nanoreactor for effective dehalogenation of α-bromoacetophenone and its derivatives in aqueous medium under white light irradiation. Such light-harvesting systems has greatly potential applications to realize some organic photocatalytic synthesis in aqueous environment.

Exploring interaction modes between polysaccharide-based selectors and biologically active 4,4′-bipyridines by experimental and computational analysis

In the last few years, chiral 4,4′-bipyridine derivatives have been developed for different applications in catalysis, enantioseparation science, supramolecular and theoretical chemistry by modulating the activity of the molecular system through the introduction of specific substituents in the heteroaromatic scaffold. More recently, the biological activity of 2′-substituted-3,3′,5,5′-tetrachloro-2-iodo-4,4′-bipyridines has been explored in the field of transthyretin (TTR) fibrillogenesis inhibition, and the anticancer cytotoxicity of some derivatives is currently under systematic investigation. In this frame, the high-performance liquid chromatography (HPLC) enantioseparation of four atropisomeric 2,2′-disubstituted-4,4′-bipyridines (R, R’ = Ar, I), which contain multiple interaction sites, such as hydrogen bonding (HB) donors and acceptors, halogen bond (XB) donors, and π-extended electronic clouds, was explored by using n-hexane (Hex)/2-propanol (2-PrOH) 90:10 v/v as a mobile phase (MP), and eight chiral columns with coated and immobilized amylose- and cellulose-based selectors. The impact of subtle structural variations of analytes and selectors on their mutual intermolecular interactivity was evaluated in terms of retention (k) and selectivity (α) factors. On this basis, chromatographic analysis based on systematic screening of analytes and selectors was integrated with electrostatic potential (V) analysis and molecular dynamics (MD) simulations as computational techniques. The effect of temperature on retention, selectivity, and enantiomer elution order (EEO) of the analytes with coated and immobilized amylose tris(3,5-dimethylphenylcarbamate) was also considered by comparing the variation of the thermodynamic profile associated with each enantioseparation. Chromatographic responses proved to be strictly dependent on specific regions within the analyte, and functions of different interactions sites of the analytes as the structure of the chiral selector changes were significantly disclosed.

Solid-state supramolecular structures and excellent photothermal activities of dimeric zinc(II) phthalocyanines axially bridged with bipyridine derivatives

Metal-ligand axial coordination of zinc(II) phthalocyanines is an efficient strategy for regulation of structures and properties. In this work, we designed and prepared four unsubstituted zinc(II) phthalocyanine (ZnPc) dimer-based supramolecular complexes (1–4) via axtial coordination with bipyridine derivatives. Single crystal X-ray analysis revealed that the four novel complexes were dimeric (i.e. ZnPc-ligand-ZnPc), with H-shape for 1, saddle-like for 2, and Z-shapes for 3 and 4. It's interesting that a pair of saddle-like dimers of 2 crossed each other to form an interlocked tetramer structure. Furthermore, 3 and 4 were dense stacking because of their semirigid ligands, which significantly enhanced the intermolecular interactions. Intriguingly, in the crystal structure of 4, the naphthalimide ring of the ligand embedded into two neighboring phthalocyanine macrocycles, resulting in a slipped sandwich structure of ZnPc-naphthalimide-ZnPc with double π···π interactions. More importantly, the strong intermolecular interactions led to very broad absorption spectra in vis-NIR region, quenched fluorescence, and highly efficient photothermal effect. Upon irradiation, 3 and 4 could reach up to 85.7 °C and 89.2 °C, respectively, enabling them to serve as outstanding photothermal conversion materials used for photothermal imaging and therapy.

Synthesis and Luminescence Spectral Properties of New Cyano-Substituted 2,2′-Bipyridine Derivatives

Synthesis and Luminescence Spectral Properties of New Cyano-Substituted 2,2′-Bipyridine Derivatives

Expanding the Structural Diversity and Functional Scope of Diphenylalanine-Based Peptide Architectures by Hierarchical Coassembly.

Modulation of the structural diversity of diphenylalanine-based assemblies by molecular modification and solvent alteration has been extensively explored for bio- and nanotechnology. However, regulation of the structural transition of assemblies based on this minimal building block into tunable supramolecular nanostructures and further construction of smart supramolecular materials with multiple responsiveness are still an unmet need. Coassembly, the tactic employed by natural systems to expand the architectural space, has been rarely explored. Herein, we present a coassembly approach to investigate the morphology manipulation of assemblies formed by N-terminally capped diphenylalanine by mixing with various bipyridine derivatives through intermolecular hydrogen bonding. The coassembly-induced structural diversity is fully studied by a set of biophysical techniques and computational simulations. Moreover, multiple-responsive two-component supramolecular gels are constructed through the incorporation of functional bipyridine molecules into the coassemblies. This study not only depicts the coassembly strategy to manipulate the hierarchical nanoarchitecture and morphology transition of diphenylalanine-based assemblies by supramolecular interactions but also promotes the rational design and development of smart hydrogel-based biomaterials responsive to various external stimuli.