Strong Hydrogen Bonds Research Articles

Chalcone derivatives containing 1,2,4-triazole and pyridine moiety: design, synthesis, and antiviral activity.

A series of chalcone derivatives containing 1,2,4-triazole and pyridine were designed and synthesized, and their antiviral activities against tobacco mosaic virus (TMV) were evaluated. Notably, S7 (EC50 = 89.7μg/mL) exhibited excellent curative activity against the TMV, which was superior to that of ningnanmycin (NNM: EC50 = 201.7μg/mL). Molecular docking showed that S7 exhibited satisfactory affinities for the TMV coat protein (TMV-CP), with four strong conventional hydrogen bonds with amino acid residues. Further, microscale thermophoresis (MST) showed that S7 (Kd = 0.5340 ± 0.2233 μmol/L) bound more strongly to TMV-CP than NNM (Kd = 5.1186 ± 1.9568μmol/L). The results of chlorophyll content, malondialdehyde (MDA) content, and biological enzyme activity confirmed that S7 enhanced the disease resistance of tobacco plants by affecting the change of chlorophyll content, interfering with plant lipid peroxidation, and enhancing SOD activity in plants, respectively.

Dynamic anti-correlations of water hydrogen bonds

Water is characterized by strong intermolecular hydrogen bonds (H-bonds) between molecules. The two hydrogen atoms in one water molecule can form H-bonds of dissimilar length. Although intimately connected to water’s anomalous properties, the details and the origins of the asymmetry have remained elusive. We study water’s H-bonds using the O-D stretching vibrations as sensitive reporters of H-bonding of D2O and HOD in dimethylformamide. Broader inhomogeneous linewidths of the OD band of HOD compared to the symmetric and asymmetric OD stretching modes of D2O together with density functional theory calculations provide evidence for markedly anti-correlated H-bonds: water preferentially forms one weak and one strong H-bond. Coupling peaks in the spectra for D2O directly demonstrate anti-correlated H-bonds and these anti-correlations are modulated by thermal motions of water on a sub-picosecond timescale. Experimentally inferred H-bond distributions suggest that the anti-correlations are a direct consequence of the H-bonding potential of XH2 groups, which we confirm for the ND2 group of urea. These structural and dynamic insights into H-bonding are essential for understanding the relationship between the H-bonded structure and phase behavior of water.

“Three birds with one stone” strategy for building easily reprocessable cellulosic thermosetting resins

Cellulose is the most abundant natural polypolysaccharide and is an ideal raw material to replace petroleum-based plastics. However, natural cellulose is difficult to be thermo-processed like conventional plastics because of the rich and strong hydrogen bonds interactions. In this study, a series of dialdehyde derivatives of cellulose (DACs) were prepared by periodate oxidation of cellulose, and cellulose covalent adaptive networks based on acetal dynamic covalent bonds (ACCs) were prepared using dipentaerythritol as a crosslinker for DAC. This strategy can introduce acetal bonds, weaken hydrogen bonds, and reduce rigidity to kill three birds with one stone. The excellent reprocessing performance of ACCs is attributed to the reconstruction of the cellulose hydrogen bond network by acetal bonds, and the reversible exchange reaction of the acetal bonds at high temperatures endows the cellulose chains with mobility, allowing ACCs to be remodeled by hot pressing at 90°C for 15 min. The excellent stability and reprocessability of ACCs hold the promise of replacing current non-renewable petroleum-based plastics and provide inspiration for the development of other types of biomass plastics.

Tunable protic ionic liquid catalysts for the efficient one-step synthesis of isosorbide-based polycarbonates

Using CO2-derived dimethyl carbonate (DMC) instead of diphenyl carbonate (DPC) as a carbonyl source for synthesizing bio-based polycarbonates is a green and cost-effective route. However, the synthesis of high-performance polycarbonates via the DMC route remains challenging due to the poor reactivity and selectivity of DMC compared to DPC. Herein, we designed a series of highly active protic ionic liquid (PIL) catalysts for the synthesis of poly(isosorbide carbonate) (PIC) from DMC with ISB. The influences of the structures of anion and cation on the catalytic activity of PILs were systematically studied. Compared with the reported aprotic IL catalysts, the unique reactive hydrogen of the cation in PILs could form a strong hydrogen bond interaction with the carbonyl group of DMC, resulting in higher reactivity of the carbonyl carbon of DMC. Moreover, the nucleophilicity of the anion could be easily tuned by adjusting the pKa value, which effectively realized the balance of the reactivity difference between exo-OH and endo-OH in ISB. Among them, [DBUH][Im] showed the highest catalytic activity, and the weight-average molecular weight (Mw) and glass transition temperature of PIC reached 55,700 g/mol and 160 °C, respectively. Combined with NMR analyses and DFT calculations, the mechanism that exhibited the synergetic catalytic effect of anion-cation for the polymerization of DMC and ISB was presented.

Self-driven photoelectrochemical sensor based on Z-type perovskite heterojunction for profenofos detection in milk and cabbage

With growing public concern about the accumulation of pesticide residues in food and their potential impacts on health and the environment, the demand for advanced detection technologies has become more critical. To address this need, we have developed an innovative self-driven photoelectrochemical (PEC) sensor, utilizing a Z-type heterojunction structure. This sensor exploited the synergistic interactions between the carbonyl groups in polyvinylpyrrolidone and the Pb2+ ions in the perovskite, and was further enhanced by the strong hydrogen bonds formed between polyethylene glycol and MA+. To optimize the sensor's performance, we incorporated perylene tetracarboxylic acid, which enhanced interface adhesion and promotes charge separation, elements crucial for the visible light-driven PEC process. This strategic design resulted in a sensor with high sensitivity and stability, which was capable of detecting profenofos residues in complex food matrices such as milk and cabbage. The sensor demonstrated a linear detection range from 0.1 to 107ngL-1 and an exceptional detection limit of 0.033ngL-1. When applied to real samples, the sensor achieved recovery rates ranging from 96.68% to 107.2%, with relative standard deviations between 1.08% and 4.54%. In light of these results, the sensor not only showed high efficiency in real-time monitoring of pesticide contamination, but also highlights its significant potential for broader application in the field of food safety.

Ethylene glycol-mediated dispersion enhancement of oxidized MWCNTs for improved electrochemical performance in flexible, free-standing OCNT/LMO electrode

The rapid advancement of flexible electronics and wearables necessitates high-capacity flexible batteries that adapt to various shapes and movements. Carbon nanotubes (CNTs), with their exceptional electrical conductivity, mechanical flexibility, and structural stability, are promising candidates. However, achieving a well-dispersed and uniform distribution of CNTs and heavy active materials like lithium manganese oxide (LMO) particles in different matrices is challenging due to issues with agglomeration and quick sedimentation. This study uses ethylene glycol (EG) as a dispersing solvent to form strong hydrogen bonds with oxidized CNTs, enhancing dispersion stability and preventing re-aggregation. Its higher viscosity compared to water helps in better stabilizing and dispersing LMO particles within the oxidized CNT suspension by reducing sedimentation. The OCNT/LMO-EG electrode shows a higher discharge capacity of 128 mAh/g with Coulombic efficiency of 99.6% after 200 cycles, compared to the OCNT/LMO-W2 electrode, which uses water for dispersion and achieves 108 mAh/g with 99.6% efficiency. These results highlight ethylene glycol's potential to improve CNT and LMO dispersion, resulting in a homogeneous electrode structure with enhanced conductivity and higher capacity.

Encapsulating phase change materials into melamine formaldehyde sponge assembled with polypyrrole modified halloysite nanotube for effective solar-thermal energy storage and solar-thermal-electric conversion

Exploiting inexpensive composite phase change materials (PCMs) with comprehensive characteristics of high encapsulation efficiency, good leakage resistance, strong flexibility, high heat conductivity, and powerful light absorption is considerably imperative for their solar-thermal and solar-thermal-electric conversion. Herein, polypyrrole (PPy) modified halloysite (HNT/PPy) was assembled into the pores of melamine formaldehyde (MF) sponge to construct hierarchical porous structure (MHP), in which PPy serves as light absorber and heat conducting agent to consolidate the light absorption and thermal conductivity, while the interwoven HNT in MF not only acts as carrier to provide sufficient space for guaranteeing more PCMs’ encapsulation, but also dramatically narrows MF’s pore size and prevents PCMs’ leakage. As expected, the MHP can encapsulate as high as 95 wt% of polyethylene glycol (PEG) with extremely high latent heat of 177.8 J g−1 (PEG@MHP). The rich hydroxyl groups on PEG, PVA and HNT form strong hydrogen bond interaction, effectively improving the leakage-proof performance of PEG@MHP. Especially, PEG@MHP with 82 wt% encapsulation ratio (PEG@MHP-82) demonstrates unexceptionable leakage resistance (negligible leakage at 100 °C), strong light absorption (97 %), good photothermal conversion efficiency (90.36 %), and high thermal conductivity (0.235 W m−1 K−1). Except that, the solar-thermal-electric (STE) conversion system assembled with PEG@MHP-82 enables efficient voltage and current outputs of 587 mV and 83.3 mA respectively under 3 kW m−2 with heat dissipation in water. Encouragingly, the voltage output still achieves 154.7 mV under actual outdoor illumination (0.984 kW m−2). This work provides a simple method to efficiently encapsulate PCMs for realizing high-efficiency solar-thermal and solar-thermal-electric conversion.

Nanoarchitectonics of SiO2 composite hydrogel in inorganic solution: Simulation and experimental analysis

Polyacrylamide hydrogels are widely used in medicine, petrochemical, water treatment and other fields, among which polyacrylamide hydrogels play an important role in oilfield Profile control and water shutoff and enhanced oil recovery, however, there are few reports on the effect of different inorganic salt solutions on the properties of SiO2 composite hydrogel. In this paper, a cross-linked SiO2 composite hydrogel was constructed using Materials Studio software for the first time, and its structure and properties in inorganic salt aqueous solutions were studied. The results show that the addition of inorganic salts can weaken the interaction between water molecules and hydrogels, and this effect is minimal in calcium chloride solution. The radial distribution function shows that there are strong hydrogen bonds between nitrogen and oxygen atoms in the amide group and water molecules, but there are van der Waals forces between oxygen and water atoms, and the addition of inorganic salts will enhance the hydration of nitrogen atoms in the amide group and the interaction between monovalent ions and amide groups was greater than that between bivalent ions. At the same time, the addition of inorganic salts can also enhance the diffusion ability of water molecules and the fluidity of polymer chains. Among the four inorganic salt solutions, Calcium chloride solution has the least effect on the polymer chain and the cross-linked SiO2 composite hydrogel has the best expansion performance in calcium chloride solution, which is basically consistent with the experimental results, this has a potential application prospect in the reservoir with high calcium content for profile control and water plugging and enhanced oil recovery.

A transparent, moisturizing, antibacterial and mechanically flexible hydrogel for emergency conservation of unearthed bone relics

The excavation of bone relics holds significant implications for studying the origins, evolution, and decline of cultures. However, effectively protecting fragile unearthed bone relics like ivory remains challenging due to environmental changes from burial to exposure, which can cause dehydration and microorganism proliferation, leading to deterioration. Herein, a moisturizing and antibacterial polyacrylamide (PAM) hydrogel containing glycerol (Gly) and betaine hydrochloride (Bh) is designed for emergency conservation of unearthed bone relics. Gly forms strong hydrogen bonds with the water molecules in the hydrogel, which not only inhibits the diffusion of water molecules into the air, thereby extending their moisturizing duration, but also prevents the diffusion of water molecules into bone relics, avoiding reverse osmosis damage to the relics. Consequently, this allows the relics to maintain their initial moisture content for a prolonged period. Additionally, Gly forms hydrogen bonds with PAM, which imparts high flexibility, strength, elongation, and toughness to the hydrogel, enabling it to conform closely to curved ivory surfaces and resist external forces. In addition, the introduction of Bh significantly enhances the hydrogel’s antibacterial properties, achieving antibacterial rates of 97.96 % against Salmonella and 100 % against Escherichia coli. Based on these advantages, we have applied the hydrogel to the emergency conservation of unearthed bone relics at Sanxingdui. After applying the hydrogel to the ivory surface, the results are significant. 1 day after application, the ivory’s weight retention rate is maintained at over 95 %. Even after 7 days of protection, the appearance of the ivory remains almost unchanged, its mechanical properties are still preserved at more than 90 % of the original levels, and the growth of bacteria on the ivory surface is effectively inhibited. Therefore, this research offers a new approach to the preservation of unearthed bone relics.

The Molecular Additive N-Acetyl-L-Phenylalanine Delays the Crystallization and Suppresses the Phase Impurity for Achieving Triple-Cation Perovskite Solar Cells with Efficiency Over 25.

The crystallization process plays an important role in the formation of high-quality perovskite film for achieving efficient perovskite solar cells (PSCs), especially in the formation of mixed-cation perovskite film, as there are normally more phase impurities than in pure CH(NH2)2PbI3 (FAPbI3) film. Herein, a molecular additive strategy, i.e., introducing non-planar molecule N-acetyl-L-phenylalanine (APO) into the lead iodide (PbI2) precursor solution, is proposed to modulate crystallization kinetics and inhibit the generation of phase impurities of metastable pretreated perovskite film. The delayed crystallization process promotes a sufficient reaction between organic salts solution and inorganic Pb-I framework, and perovskite phase decomposition is prevented by forming strong hydrogen bonds between ─NH and I, resulting in the formation of uniform film with large-size crystal grains and high-purity crystalline phase. Ultimately, the target PSC devices achieve an impressive power conversion efficiency (PCE) of 25.05%, which is among the highest values of triple-cation (FAMACs) PSCs. Meanwhile, PSC modules with 10.8 cm2 obtain a PCE of 20.35%. Furthermore, the unencapsulated PSCs retain 94% of the initial efficiency after 40 days of storage under ambient conditions with 20% RH and also yield superior operational stability under light soaking at maximum power point tracking (MPPT) in nitrogen (N2) atmosphere.

Effect of hydrogen bonding strength on the structure and properties of phase-separated hydrogel from gelatin

Dynamic bonded tough hydrogels often contain phase-separated structures that facilitate multiscale energy dissipation. However, the influence of bonding strength on the phase-separated structures and properties of hydrogels has been understudied. In this work, the hydrogen bonding strength within phase-separated gelatin/acrylic acid copolymer hydrogels was modulated by varying the methyl group content in the acrylic acid copolymer. It was found the mechanical properties of the hydrogels are determined by a synergistic effect between water content and hydrogen bond strength. Both weak and strong hydrogen bonds resulted in the hydrogel with high water content and low mechanical strength. It was observed that the chain dense regions within the hydrogels became more condensed and larger with increasing hydrogen bonding strength. The high water content in gels with strong hydrogen bonds is attributed to the formation of condensed chain dense regions, which prevent significant shrinkage of the hydrogel. The combination of high water content and condensed chain dense regions resulted in sparse chain loose regions within the hydrogel, which provided water channels for ion transport, enabling high ionic conductivity even at a reduced water content of 28.9 wt%.

Sculpting Mechanical Properties of Hydrogels by Patterning Seamlessly Interlocked Stiff Skeleton

AbstractFunctional soft materials, especially hydrogels have been widely developed to achieve various soft structures and machines. However, synthetic hydrogels commonly show formula‐dependent mechanical properties to fulfill the requirements of mechanical elasticity, stiffness, toughness, and tearing‐resistance for adapting to complex application scenario. Inspired by heterostructures and materials found in nature such as leaves and insect wings, a sequential photopolymerization process combined with site‐selective patterning exposure is reported to prepare programmable hydrogels with locally heterogeneous reinforcement skeletons, i.e., interpenetrating double networks. The heterogeneous interface between soft matrices and stiff skeletons is seamlessly interlocked through strong multiple hydrogen bonds induced by phase transition. By harnessing the size, shape, and distribution of the patterned stiff skeletons, a wide range of mechanical properties of hydrogels including modulus (0.32–5.92 MPa), toughness (0.15–18 kJ m−2), dissipated energy (1–100 kJ m−3), impact resistance, and mechanical anisotropy can be readily sculpted within one material system without needing design and optimization of the complex and elusive material formulation on demand. It is believed that this simple yet powerful method relying on heterogenous patterning would guide the development of functional hydrogel materials with programmable mechanical properties toward potential engineering applications, such as damping and flexible circuits.

Synthesis, structure elucidation and characterization of new heterocyclic compound: 2-aminobenzimidazolium-4-carboxybutanoate

The molecular compound of 2-amino benzimidazolium-4-carboxybutanoate (AB4CB) was synthesized from 2-aminobenzimidazole (AB) and 4-carboxybutanoic acid (4CB) in equimolar ratio. A brown color single crystal was successfully grown by slow evaporation solution growth technique (SEST). The single crystal X-ray diffraction technique reveals that the grown crystal is in tetragonal crystal system with centrosymmetric I41/a space group. The structure is stabilized through NH…O intermolecular hydrogen bond interaction. From FTIR and Raman spectroscopy, the shift in the wavenumber of fundamental bands such as NH, CH and C = O stretching vibrations evidences the existence of strong hydrogen bond formation, which enhances the bioactivity of the compound. 1H and 13C NMR spectral analyses were used to predict the presence of proton and carbon in the tittle compound. The UV–Vis absorption spectrum exhibits proton transfer from anion to cation by π-π* transition. The decomposition temperature of the grown crystal was measured by TGA/DTA studies and it shows the crystal was stable upto 259ºC. This compound demonstrates good antibacterial and antifungal activities against various bacteria and fungi when compare with standard drugs Penicillium G and Ketoconazole respectively. Further, the binding modes of the compound are ascertained by molecular docking studies against Escherichia coli and Candida albicans.

Physicochemical and Antimicrobial Properties of Lactic Acid-Based Natural Deep Eutectic Solvents as a Function of Water Content

The interest in natural deep eutectic solvents (NADESs) in green technology as an alternative to organic solvents has grown over the past decades. In this work, for the first time, the effect of dilution with water on the physicochemical and antimicrobial properties of lactic acid-based NADES with choline chloride (NADES1), sorbitol (NADES2), and glucose (NADES3) was systematically studied. According to FTIR data, after the dilution of NADESs with water, the strong hydrogen bonds weakened, however, were not destroyed after dilution of up to 40% water. The dilution of NADES with water resulted in a linear decrease in density and refractive index and in a linear increase in pH. The equations for the prediction of NADES density, pH, and refractive index as a function of water content were calculated. The viscosity decreased by half after adding approximately 10% water. The initial viscosity of NADES2 and NADES3 was significantly different. However, after adding 20% of the water, the viscosity was almost the same. The most pronounced decrease in surface tension (by 46.7%) was found for NADES1. The water activity was decreased in the following order: NADES3 > NADES1 > NADES2. The dilution of NADES with water caused a gradual increase in water activity. NADES1 showed the lowest minimal inhibitory concentrations (MIC) (7.8, 3.9, and 0.98 mg/mL) and minimum bactericidal concentrations (MBC) (15.6, 7.8, and 1.95 mg/mL) for Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus, respectively. The antimicrobial activity was decreased by 2–8 times after the addition of 40% water. The water activity for all tested NADES together with low pH could explain the antimicrobial effect. The revealed regularity can be useful for the prediction of NADES properties and for the selection of green solvents on a laboratory and industrial scale.

1H and 13C NMR and FTIR Spectroscopic Analysis of Formic Acid Dissociation Dynamics in Water.

The formation and transport of ionic charges in formic acid-water (HCOOH-H2O) mixtures with initial water mole fractions ranging from XH2Oi = 0 to 1 were investigated using 13C and 1H NMR, FTIR spectroscopy, viscosity, conductivity, and pH measurements. The maximum molar concentration of ions (H3O+ and HCOO-), along with the relative differences between theoretical and experimental densities, spin-lattice relaxation times (T1), activation energies (Ea), viscosity (η), and conductivity (σ), were identified within the range of XH2Oi ≈ 0.5-0.7. These results indicate that pure formic acid (FA) solutions predominantly consist of cyclic dimers at room temperature. As the water mole fraction increases up to 0.6, a structural shift occurs from cyclic dimers to a mixture of linear and cyclic dimers, driven by the formation of strong hydrogen bonds. Beyond a water mole fraction of 0.6, the structure transitions to linear dimers, with FA molecules behaving as free entities in the water. Furthermore, the acidity was found to increase approximately 2-fold with every 0.1 increment in water mole fraction. These findings are critical for understanding the kinetics of formic acid anions in body fluids, the structure of the hydrogen bonding network, and ionization energies.

Design, synthesis, biological and computational analysis of isatin-based bis-thiourea analogues as anti-diabetic and anti-nematode agents

A new series of isatin derivatives were synthesized, characterized by 1HNMR, 13CNMR and HREI-MS, and screened for α-glucosidase and alpha amylase inhibition. All the analogues were found to be dual inhibitors and showed good inhibitory potentials with IC50 values ranging from 5.28 ± 0.10 to 38.66 ± 0.30 µM (against alpha-amylase), and 5.45 ± 0.10 to 39.25 ± 0.50 µM (against alpha-glucosidase), as compared to the standard drug acarbose (IC50 = 11.12 ± 0.15 and 11.29 ± 0.07 µM, respectively). The most potent inhibitor among the series was analogue 24 (IC50 = 5.28 ± 0.10 for alpha-amylase and IC50 = 5.46 ± 0.10 µM for alpha-glucosidase), which has a nitro group attached at the meta-position of the phenyl ring A and the para position of phenyl ring B. Structure-activity relationship has been established mainly based on the position, nature and number of the substituent(s) attached to the phenyl ring. To investigate the binding interaction of the potent analog with the active site of an enzyme, molecular docking studies were carried out. To study the drug-likeness properties, the ADME study was also carried out. The most active compounds engage most of the amino acids composing the active site and display maximum interactions. These interactions majorly include formation of strong hydrogen bonds, which might be due to the presence of highly electronegative heteroatoms on aromatic rings. All the analogues were also tested for in vivo anti-nematodal activity against C. elegans to assess their cytotoxicity in comparison to the reference Levamisole. The cytotoxicity profile demonstrated that analogues 2, 7, 20 and 22 displayed minimum cytotoxicity at every concentration.

Local Electronic Correlation in Multicomponent Møller-Plesset Perturbation Theory.

We present in this contribution the first application of local correlation in the context of multicomponent methods. Multicomponent approaches allow for the targeted simulation of electrons together with other Fermions (most commonly protons) as quantum particles. These methods have become increasingly popular over the last years, particularly for the description of nuclear quantum effects (in strong hydrogen bonds, proton tunneling, and many more). However, most implementations are still based on canonical formulations of wave function theory, which we know for decades to be computationally inefficient for capturing dynamical correlation effects. Local correlation approaches, particularly with the use of pair natural orbitals (PNOs), enable asymptotically linear scaling of computational costs with very little impact on the overall accuracy. In this context, the efficient use of density fitting approximations in the integral calculation proves essential. We start by discussing our implementation of density-fitted NEO-MP2 and NEO-PNO-LMP2, upgrading the electronic correlation treatment up to PNO local coupled cluster level of theory. Several challenging examples are provided to benchmark the method in terms of accuracy as well as computational cost scaling. Following appropriate protocols, anharmonic corrections to localized X-H stretches can be applied routinely with little computational overhead.

Systematic Computational Approaches on Biosorption of Fluoride on Chitin: Crossover from Conventional to Short and Strong Hydrogen Bonds

Systematic Computational Approaches on Biosorption of Fluoride on Chitin: Crossover from Conventional to Short and Strong Hydrogen Bonds

Molecular diffusion in aqueous methanol solutions: The combined influence of hydrogen bonding and hydrophobic ends.

Although the nonmonotonic variation in the diffusion coefficients of alcohol and water with changing alcohol concentrations in aqueous solutions has been reported for many years, the underlying physical mechanisms remain unclear. Using molecular dynamics simulations, we investigated the molecular diffusion mechanisms in aqueous methanol solutions. Our findings reveal that the molecular diffusion is co-influenced by hydrogen bonding and the hydrophobic ends of methanol molecules. A stronger hydrogen bond (HB) network and a higher concentration of hydrophobic ends of methanol molecules both enhance molecular correlations, thereby slowing molecular diffusion in the solution. As methanol concentration increases, the HB network weakens, facilitating molecular diffusion. However, the increased concentration of hydrophobic ends counteracts this effect. Consequently, the diffusion coefficients of water and methanol molecules exhibit nonmonotonic changes. Previous studies have only focused on the role of HB networks. For the first time, we have identified the impact of the hydrophobic ends of alcohol on molecular diffusion in aqueous alcohol solutions. Our research contributes to a better understanding and manipulation of the properties of aqueous alcohol solutions and even liquids with complex compositions.

Tetrazaisoindigos:Serpentine Syntheses and Their Expected and Unexpected Photophysical and Electronic Properties.

Isoindigo, an electron-withdrawing building block for polymeric field-effect transistors, has long been considered to be non-fluorescent. Moreover, using electron-deficient heterocycle to replace the phenyl ring in the isoindigo core for better electron transport behaviour is synthetically challenging. Here we report the syntheses of a series of tetrazaisoindigos, including pyrazinoisoindigo (PyrII), pyrimidoisoindigo (PymII) and their hybrid (PyrPymII), and the investigation on their photophysical and electric properties. Proper flanking groups need to be chosen to stabilize these highly electron-deficient bislactams. Both PyrII and PymII derivatives show lower LUMO energy levels than that of naphthalene bisimide (NDI). Interestingly, PyrII is instinctively unstable and can be easily reduced, while both PymII derivatives are stable. More surprisingly, PymII derivatives are highly fluorescent and their photoluminescence quantum yields are around 40 %, 133 times higher than that of reported isoindigo derivatives. UV-vis spectroscopic results and theoretical calculations show that strong intramolecular hydrogen-bond exists in PymII, which prohibits it from non-radiative decay and accounts for its fluorescent behaviour. PymII derivatives are n-type semiconductors, while Ph-PyrII and the hybrid show balanced ambipolar charge transport behaviour, all among the best isoindigo derivatives. Our study not only discloses the structure-property relationship of tetrazaisoindigos, but also provides novel electron-deficient monomers for conjugated polymers.