Terpyridine Research Articles

Construction of Luminescent Terpyridine-Based Metallo-Bowties with Alkyl Chain-Bridged Dimerized Building Blocks.

Numerous metallo-supramolecules with well-defined sizes and shapes have been successfully constructed via the strong coordination interaction between terpyridine (TPY) moieties and ruthenium cations. However, the pseudo-octahedral geometry of <TPY-Ru-TPY> unit hampers the luminescent properties of such metallo-architectures, thus limiting their applications as optical materials. To address this issue, we herein use a flexible alkyl chain to bridge TPY building blocks, replacing conventional <TPY-Ru-TPY> linkage. The introduction of alkyl chain guides the self-assembly into desired architecture while simultaneously eliminating the quenching effects typically associated with the <TPY-Ru-TPY> linkage. More importantly, this design strategy enables the precise construction of bowtie-shaped metallo-supramolecules with significantly enhanced emission. The incorporation of alkyl chain linkage not only maintains structural integrity but also enhances optical performance, making these metallo-supramolecular assemblies highly promising for applications in advanced photonic and luminescent materials. This study offers a versatile approach to construct complex metallo-supramolecular architectures with desired optical properties.

Manipulating Intramolecular Charge Transfer in Terpyridine Derivatives towards "Turn-On" Fluorescence Chemosensors for Zn2.

A series of donor-acceptor (D-A) terpyridine derivatives with various intramolecular charge transfer interactions have been successfully synthesized bearing phenyl, methoxyphenyl, N-butyldiphenylamine (DPA), and triphenylamine (TPA) as electron-donors and terpyridine (TPY), 2,6-di(pyrazin-2-yl)pyridine (PYDPZ), and N,N-dimethylated PYDPZ (PYDPZ-2CH3) as electron acceptors. Upon the introduction of pyrazine rings instead of pyridine ones and further selective N,N'-dimethylation, the intramolecular D-A interactions are significantly enhanced, resulting in the remarkable reduced intramolecular charge transfer (ICT) transitions and quenched PL emissions in CH2Cl2 solution. However, their ICT emissions are clearly recovered upon adding Zn2+. Especially, for double positively charged compound 12, the Zn2+-induced "turn-on" green emission (λmax, em = 518 nm, Φ = 0.24) with excellent sensitivity (I/I0 = 77) and selectivity (IZn/ICd = 23) is detected. Under the optimized experimental condition (EtOH-H2O (9:1, v/v), containing 0.05 M HEPES buffer (pH = 7.4)), this probe is used to quantitative determination of Zn2+ in a water sample with an average recovery of 97.5%. Furthermore, the probe is applied to imaging of Zn2+ ions in HeLa cells and its mechanism is confirmed by the molecular dynamics simulation, in which lower coulomb potential for membrane surface adsorption and energy barrier for membrane translocation can be found.

Elucidation of Switching Mechanisms in Memristive Junctions Integrating a Iron(II)‐Ter Pyridine Diazoted Complex

AbstractAn original way of elaborating vertical metal/molecules/metal memristive junctions through diazonium electrografting of the organic layer and inkjet‐printed top electrodes is reported here. The molecule of interest is a FeII coordination complex with ter‐pyridine ligands, having a diazonium anchoring group. The resulting junction exhibits a memristive behavior characterized by a high ON/OFF ratio and plasticity property. Through the application of advanced techniques such as UV–vis and Raman time‐resolved spectroelectrochemistry, the study demonstrates the significant role of switchable azo bonds derived from diazo electrografting in memristive behavior.

Synthesis and luminescent properties of five-six-membered bis(metallacyclic) platinum(II) complexes bearing polypyridine alkynes

A series of five-six-membered bis(metallacyclic) Pt(II) complexes bearing a 2,2′-bipyridine (BPY) or 2,2′:6′,2"-terpyridine (TPY) ethynyl ligand were synthesized and characterized. The structures of N^C*N-coordinated Pt(II) complexes (−)-1 and (−)-5 were confirmed by single crystal X-ray diffraction, displaying a slightly distorted square-planar coordination environment around the Pt(II) centers. Compared to N^N*C-coordinated Pt(II) derivatives ((−)-2, (−)-4 and (−)-6), N^C*N-coordinated complexes ((−)-1, (−)-3 and (−)-5) demonstrate a more significant AIE property with a sharp luminescence variation in response to water content. In addition, due to the existence of the pendent BPY or TPY unit, N^C*N-coordinated Pt(II) complexes show a luminescence response to Zn2+ ions. Cytotoxicity and cell imaging of luminescent five-six-membered bis(metallacyclic) Pt(II) complexes with polypyridine alkynes have been evaluated.

Dual-continuous microneedle patch integrating transdermal delivery of pH-sensitive licorzinc MOFs and Zn2+ hydrogel sensors for treating alopecia areata

Licorzinc is a commonly used immunomodulator, but faces poor water solubility, high oral dose, and side effects of zinc accumulation by long-term administration. Herein, a new licorzincform was developed by adsorbing glycyrrhizic acid (GA) into zeolitic imidazolate framework-8 (GA@ZIF-8) with superior solubility and acid-responsive drug release properties. Then, a dual-continuous microneedle patch was developed for simultaneous transdermal delivery of GA@ZIF-8 and monitoring Zn2+ in local tissues, where dissolving microneedles as a drug delivery unit were fabricated from hyaluronic acid. In contrast, swollen hydrogel microneedles as a diagnostic unit were prepared from double cross-linking of N-acryloyl-glycinamide and α-methylacrylic acid and hybridized with Eu3+ and terpyridine (TPy). The microneedles for transdermal GA@ZIF-8 delivery were completely dissolved in 2 min, which improved the cyclophosphamide-induced hair follicle recession in mice by reducing CD8+NKG2D+ T cells infiltration, inhibiting Jak receptor activation, and decreasing IL-15 and IFN-γ. Additionally, as a sensor unit, the microneedles rapidly absorbed water swelled when stabbed into the skin, and fluoresced red when exposed to 365 nm light. Zn2+ in the inter tissue fluid competes with Eu3+ in the TPy-Eu3+ complex and coordinates with Tpy, which triggers a change in fluorescence. Notably, the detection Zn2+concentration range was 10–8 M–10–1 M, and it was not disturbed by metal ions including Na+, K+, Mg2+, and Ca2+, suggesting that it is competent to be applied as a real-time chemosensor of Zn2+. Collectively, this newly designed system with both therapeutic and diagnostic functions provides a new strategy for treating zinc-related diseases.

Voltammetric Sensing of Chloride Based on a Redox-Active Complex: A Terpyridine-Co(II)-Dipyrromethene Functionalized Anion Receptor Deposited on a Gold Electrode.

A redox-active complex containing Co(II) connected to a terpyridine (TPY) and dipyrromethene functionalized anion receptor (DPM-AR) was created on a gold electrode surface. This host-guest supramolecular system based on a redox-active layer was used for voltammetric detection of chloride anions in aqueous solutions. The sensing mechanism was based on the changes in the redox activity of the complex observed upon binding of the anion to the receptor. The electron transfer coefficient (α) and electron transfer rate constant (k0) for the modified gold electrodes were calculated based on Cyclic Voltammetry (CV) experiments results. On the other hand, the sensing abilities were examined using Square Wave Voltammetry (SWV). More importantly, the anion receptor was selective to chloride, resulting in the highest change in Co(II) current intensity and allowing to distinguish chloride, sulfate and bromide. The proposed system displayed the highest sensitivity to Cl- with a limit of detection of 0.50 fM. The order of selectivity was: Cl- > SO42- > Br-, which was confirmed by the binding constants (K) and reaction coupling efficiencies (RCE).

An Emerging Stannous Fluoride Complex‐Enabled Highly Efficient Electron Collection and High Stability of Tin‐Based Perovskite Solar Cells

In advancing high‐performance tin‐based perovskite solar cells, rapid crystallization and oxidation susceptibility are key challenges. SnF2, often added to control crystallization and oxidation, may impact cell performance, particularly postannealing. This study uses in situ variable‐temperature X‐Ray diffraction to examine SnF2's physicochemical behavior and phase transitions in these cells. The analysis highlights how residual SnF2 affects carrier recombination through energy‐level structures. Postfilm formation, SnF2 chemically interacts with 2,2′:6′,2″‐Terpyridine (TPY), forming a stannous fluoride complex that enhances electron transport and energy alignment. Crucially, TPY passivates surface defects and reduces tin vacancies, boosting device stability. The experimental results indicate that the unencapsulated devices in air atmosphere exhibit a stabilized power output retention rate above 90% of the initial efficiency after 29.5 h. After ≈800 h of continuous illumination in ambient air, the conversion efficiency can still be maintained above 100%. Remarkably, t90 (time to retain 90% efficiency) of the target device in pure oxygen is over 24 h.

Designable Photo-Responsive Micron-Scale Ultrathin Peptoid Nanobelts for Enhanced Performance on Hydrogen Evolution Reaction.

The development of high-reactive single-atom catalysts (SACs) based on long-range-ordered ultrathin organic nanomaterials (UTONMs) (i.e., below 3nm) provides a significant tactic for the advancement in hydrogen evolution reactions (HER) but remains challenging. Herein, photo-responsive ultrathin peptoid nanobelts (UTPNBs) with a thickness of ≈2.2nm and micron-scaled length are generated using the self-assembly of azobenzene-containing amphiphilic ternary alternating peptoids. The pendants hydrophobic conjugate stacking mechanism reveals the formation of 1D ultralong UTPNBs, whose thickness is dictated by the length of side groups that are linked to peptoid backbones. The photo-responsive feature is demonstrated by a reversible morphological transformation from UTPNBs to nanospheres (21.5nm) upon alternative irradiation with UV and visible lights. Furthermore, the electrocatalyst performance of these aggregates co-decorated with nitrogen-rich ligand of terpyridine (TE) and uniformly-distributed atomic platinum (Pt) is evaluated toward HER, with a photo-controllable electrocatalyst activity that highly depended on both the presence of Pt element and structural characteristic of substrates. The Pt-based SACs using TE-modified UTPNBs as support exhibit a favorable electrocatalytic capacity with an overpotential of ≈28mV at a current density of 10mA cm-2. This work presents a promising strategy to fabricate stimuli-responsive UTONMs-based catalysts with controllable HER catalytic performance.

Near-IR Electrochromic Film with High Optical Contrast and Stability Prepared by Oxidative Electropolymerization of Triphenylamine Modified Terpyridine Platinum(II) Chloride.

Terpyridine (TPY) platinum(II) chloride with a triphenylamine (TPA) group was successfully synthesized. The strong intramolecular Donor(TPA)-Acceptor(TPY) interaction induced the low-energy absorption band, mixing the spin-allowed singlet dπ(Pt)→π*(TPY) metal-to-ligand charge transfer (MLCT) with the chloride ligand-to-metal charge transfer (LMCT) and chloride ligand-to-ligand (TPY) charge transfer (LLCT) transitions, to bathochromically shift to λmax = 449 nm with significant enhancement and broadening effects. Using the cyclic voltammetry method, its oxidative electropolymerization (EP) films on working Pt disk and ITO electrodes were produced with tunable thickness and diffusion controlled redox behavior, which were characterized by the SEM, EDS, FT-IR, and AC impedance methods. Upon applying +1.4 V voltage, the sandwich-type electrochromic device (ECD) with ca. 290 nm thickness of the EP film exhibits a distinct color transformation from red (CIE coordinates: L = 50.75, a = 18.58, b = 5.69) to dark blue (CIE coordinates: L = 45.65, a = -1.35, b = -12.49). Good electrochromic (EC) parameters, such as a large optical contrast (ΔT%) of 78%, quick coloration and bleaching response times of 2.9 s and 1.1 s, high coloration and bleaching efficiencies of 278.0 and 390.5 C-1·cm2, and good cycling stability (maintains 70% of the initial ΔT% value after 3200 voltage switching cycles), were obtained.

On sombor indices of tetraphenylethylene, terpyridine rosettes and QSPR analysis on fluorescence properties of several aromatic hetero‐cyclic species

AbstractAromatic heterocyclic compounds have received a lot of interest due to their various important medicinal and biological applications. The broad synthetic investigation and functional usefulness of heterocyclic molecules is driving a surge in research interest. They are found in more than 90% of innovative medications and bridge the gap between biology and chemistry, where so much scientific discovery and application happens. Heterocycles are also useful in a variety of domains, including pharmaceutical chemistry, biochemistry, and others. In this article, quantitative structure‐property relationship (QSPR) models is developed using sombor indices to predict fluorescence properties of aromatic hetero‐cyclic species based on their structural features. This allows researchers to estimate the fluorescence behavior of new molecules without performing experimental measurements. As an application, we have computed the sombor indices for self‐assembled supramolecular graphs made of terpyridine (TPE) and tetraphenylethylene (TPY) molecules that are produced as rosette cycles. This form of rosettes graph is used in electrical sensors, light emitting diodes, bioimaging and photoelectric devices, and so on. Tetraphenylethylene can be used to make fluorescent probes for next‐generation sensing applications with typical induced aggregative emission behavior.

Functionalization of Donor–π–Acceptor Hole Transport Materials Enhances Crystallization and Defect Passivation in Inverted Perovskite Solar Cells: Achieving Power Conversion Efficiency &gt;21% (Area: 1.96 cm2) and Impressive Stability

Inverted perovskite solar cells (PSCs) mainly adopt polytriarylamine (PTAA) for the hole transport material (HTM), which usually brings about inferior interfacial contact owing to their hydrophobicity, high‐lying highest occupied molecular orbital energy level, and deficiency of passivation groups. Herein, a series of donor–π–acceptor (D–π–A) type small molecules is demonstrated based on 2,2′:6′,2″‐terpyridine (TPy) as the acceptor moiety, benzene ring as the π‐linker, and incorporating various donors to act as HTMs. These TPy‐based molecules coated atop PTAA manipulate the energy level and surface wettability, but the incorporation of the phenoxazine (POZ) donor can be prominent for enhancing charge transport and defect passivation, thereby simultaneously addressing the above‐mentioned issues. The highest power conversion efficiency of 22.36% can be achieved with an open‐circuit voltage (VOC) of 1.15 V, a short‐circuit current density (JSC) of 23.96 mA cm−2, and a fill factor (FF) of 81.16% for the optimized POZ‐TPy‐modified device. Moreover, the power PCE of a large POZ‐TPy‐modified device (1.96 cm2) can still reach more than 21%. These results are among one of the highest efficiencies for inverted PSCs, indicating the enormous potential of POZ‐TPy HTM in future perovskite applications.

Distinct fluorescence state, mechanofluorochromism of terpyridine conjugated fluorophores and the reusable sensing of nitroaromatics in aqueous medium

Terpyridine derivatives showed charge transfer, locally excited and excimeric emission depending on the aromatic substituents, distinct mechanofluorochromism and reusable picric acid sensing.

Dual-Ligand Near-Infrared Luminescent Lanthanide-Based Metal-Organic Framework Coupled with In Vivo Microdialysis for Highly Sensitive Ratiometric Detection of Zn2+ in a Mouse Model of Alzheimer's Disease.

Zinc, which is the second most abundant trace element in the human central nervous system, is closely associated with Alzheimer's disease (AD). However, attempts to develop highly sensitive and selective sensing systems for Zn2+ in the brain have not been successful. Here, we used a one-step solvothermal method to design and prepare a metal-organic framework (MOF) containing the dual ligands, terephthalic acid (H2BDC) and 2,2':6',2″-terpyridine (TPY), with Eu3+ as a metal node. This MOF is denoted as Eu-MOF/BDC-TPY. Adjustment of the size and morphology of Eu-MOF/BDC-TPY allowed the dual ligands to produce multiple luminescence peaks, which could be interpreted via ratiometric fluorescence to detect Zn2+ using the ratio of Eu3+-based emission, as the internal reference, and ligand-based emission, as the indicator. Thus, Eu-MOF/BDC-TPY not only displayed higher selectivity than other metal cations but also offered a highly accurate, sensitive, wide linear, color change-based technique for detecting Zn2+ at concentrations ranging from 1 nM to 2 μM, with a low limit of detection (0.08 nM). Moreover, Eu-MOF/BDC-TPY maintained structural stability and displayed a fluorescence intensity of at least 95.4% following storage in water for 6 months. More importantly, Eu-MOF/BDC-TPY sensed the presence of Zn2+ markedly rapidly (within 5 s), which was very useful in practical application. Furthermore, the results of our ratiometric luminescent method-based analysis of Zn2+ in AD mouse brains were consistent with those obtained using inductively coupled plasma mass spectrometry.

On degree based topological indices of self‐assembled tetraphenylethylene and terpyridine rosettes

AbstractA technique is described to compute topological indices for supramolecular rosettes of tetraphenylethylene (TPE) and terpyridine (TPY) ligands with its applications on physicochemical and biological properties. This technique, we have applied to a self‐assembled TPE and TPY supramolecular graphs which is obtained in the form of rosette cycles. Also these type of rosettes graph finds significant applications in electrical sensors, light emitting diodes, bioimaging and photoelectric devices, and so forth. As regarded to the next generation sensing applications with a typical induced aggregative emission behavior, tetraphenylethylene can be utilized in constructing fluorescent probes. For this supramolecular systems we have done a work by computing some topological indices such as the variants of Zagreb Index, Randić Index, Sum Connectivity Index, ABC Index, and Harmonic Index.

Shape-Dependent Complementary Ditopic Terpyridine Pair with Two Levels of Self-Recognition for Coordination-Driven Self-Assembly.

Molecular recognition in biological systems plays a vital role in the precise construction of biomacromolecules and the corresponding biological activities. Such recognition mainly relies on the highly specific binding of complementary molecular pairs with complementary sizes, shapes, and intermolecular forces. It still remains challenging to develop artificial complementary motif pairs for coordination-driven self-assembly. Herein, a series of shape-dependent complementary motif pairs, based on ditopic 2,2':6',2″-terpyridine (TPY) backbone, are designed and synthesized. The fidelity degrees of self-assemblies from these motifs are carefully evaluated by multi-dimensional mass spectrometry, nuclear magnetic resonance spectroscopy, and molecular modeling. In addition, two levels of self-recognition in both homoleptic and heteroleptic assembly are discovered in the assembled system. Through finely tuning the shape and size of the ligands, a complementary pair is developed with error-free narcissistically self-sorting at two levels of self-recognition, and the intrinsic principle is carefully investigated.

Magneto-Responsive Nanocomposites with a Metal–Ligand Supramolecular Matrix

Magneto-responsive nanocomposites are prepared by mixing 1–5 vol % of Fe nanoparticles (NPs) in a metallo-supramolecular network made of poly(n-butyl acrylate) (PnBA) bearing terpyridine side groups and cross-linked by the addition of different amounts of Zn2+ ions. To have a clear understanding of the stepwise increase of complexity, the thermomechanical behavior of these materials was characterized through shear linear rheology at each step of their preparation. The metallo-supramolecular networks reveal a clear transition from polymer- to network-driven dynamics when passing progressively from low (<0 °C) to high temperature. While terpyridine (TPy)–Zn2+ complexes are usually treated as independent “stickers”, the analysis of our master curves strongly suggests their aggregation. After the addition of 1–5 vol % of Fe nanoparticles within the supramolecular networks, we evidence the presence of TPy–NP bonds, resulting in a hybrid network of much longer relaxation time. Lastly, we combine thermal imaging and induction heating to emphasize the signature of sticker dissociation, offering new technical solutions to deepen our fundamental understanding of supramolecular networks.

Resin with short-range π-π stacking aggregates for an efficient photocatalyst

A short-range π-π stacking aggregate photocatalyst (TE-resin) was facilely prepared by covalent grafting TE molecules onto crosslinked polystyrene-based macroporous resin, which displays short charge migration distance and efficient separation of electrons and holes, improved light absorption range and wettability , so TE-resin exhibits excellent photocatalytic activity and stability. • Short range π-π stacking aggregates were constructed by resin as a support. • Short-range π-π stacking aggregates display improved photocatalytic activity. • Short-range π-π stacking aggregates reduce the charge recombination efficiency. • Aggregate has good stability due to covalent bond connection between it and resin. Self-assembled supramolecular photocatalysts have aroused intensive attraction in extensive fields of solar energy conversion, water splitting and energy storage. However, the photocatalysts constructed by long range π-π stacking interaction usually display low photocatalytic activity because the holes and electrons recombine easily as they migrate along the long range π-π stacking structure. To overcome their shortcoming, for the first time, short-range π-π stacking aggregates were facilely prepared by covalent grafting 4′-(pethanediamine phenyl)-2,2′:6′,2″-terpyridine (TE) onto crosslinked polystyrene macroporous resin to form an efficient and stable photocatalyst. In the grafted resin, TE molecules linked to the resin molecules form a monolayer structure by short-range π-π stacking interaction along the polymer chains, which not only shortens the charge migration distance and reduces the charge recombination efficiency, but also efficiently improves light absorption range and wettability of the as-prepared photocatalyst. The above advantages endow the as-prepared photocatalyst with an excellent photocatalytic performance, for example, it affords a hydrogen evolution rate of 227.5 umol g -1 h −1 under UV–vis irradiation. Moreover, the covalent bond connection between TE aggregates and resin improves the stability of TE aggregates, enhancing their recycling. Overall, our work provides a convenient route for the preparation of efficient and stable short-range π-π aggregate photocatalyst assisted by resin for environmental and energetic applications.

Co-existence of five- and six-coordinate iron(II) species captured in a geometrically strained spin-crossover Hofmann framework.

Inclusion of an angular bridging ligand, 4,2':6',4''-terpyridine (TPy), into a Hofmann-type framework produces an irregular network in which six- and five-coordinate FeII species co-exist. The octahedral sites show thermally-induced spin-crossover (SCO) and the rare five-coordinate FeII sites are high-spin.

Insight into structure-property relationship of organometallic terpyridine wires: Combined theoretical and experimental study

Recent development in combined theoretical and experimental analysis methods offer an attractive opportunity to investigate organometallic materials. The selection of optimally combined characterization techniques allows for an effective description and even prediction of structure-property relationship occurring in terpyridine (TPY) molecules. In this work, secondary ion mass spectrometry (SIMS), quantitative and qualitative characterization, hand-in-hand, with density functional theory (DFT) calculations, can aid analysis of the chemical stability and reactivity of organic compounds. A case study was based on the characterization of [M-(TPY)2]2+ complexes (M: Co/Fe) with specific organic and organometallic architectures. The SIMS mass spectra showed the step-by-step molecules fragmentation and the quantitative SIMS analysis allowed to predict its direction. Analysis of electron density, electrostatic potential visualization, and calculated bonds length and HOMO-LUMO energetic gap were employed to confirm the differences between the bond-breaking mechanism depending on the metal atom bound to the terpyridine. The combined DFT/SIMS approach was successfully used to assess the chemical stability of various isomers of the TPY compounds, and to determine the possible fragmentation pathways depending largely on the metal centre present within the TPY structure.

Charge-transfer regulated visible light driven photocatalytic H2 production and CO2 reduction in tetrathiafulvalene based coordination polymer gel

The much-needed renewable alternatives to fossil fuel can be achieved efficiently and sustainably by converting solar energy to fuels via hydrogen generation from water or CO2 reduction. Herein, a soft processable metal-organic hybrid material is developed and studied for photocatalytic activity towards H2 production and CO2 reduction to CO and CH4 under visible light as well as direct sunlight irradiation. A tetrapodal low molecular weight gelator (LMWG) is synthesized by integrating tetrathiafulvalene (TTF) and terpyridine (TPY) derivatives through amide linkages and results in TPY-TTF LMWG. The TPY-TTF LMWG acts as a linker, and self-assembly of this gelator molecules with ZnII ions results in a coordination polymer gel (CPG); Zn-TPY-TTF. The Zn-TPY-TTF CPG shows high photocatalytic activity towards H2 production (530 μmol g−1h−1) and CO2 reduction to CO (438 μmol g−1h−1, selectivity > 99%) regulated by charge-transfer interactions. Furthermore, in situ stabilization of Pt nanoparticles on CPG (Pt@Zn-TPY-TTF) enhances H2 evolution (14727 μmol g−1h−1). Importantly, Pt@Zn-TPY-TTF CPG produces CH4 (292 μmol g−1h−1, selectivity > 97%) as CO2 reduction product instead of CO. The real-time CO2 reduction reaction is monitored by in situ DRIFT study, and the plausible mechanism is derived computationally.