N-containing Ligands Research Articles

Two Thiophene-Functionalized Co-MOFs as Green Heterogeneous Catalysts for the Biginelli Reaction.

Two Co(II) metal-organic frameworks (Co-MOFs), namely, [Co(DMTDC)(bimb)]n (Co-MOF-1) and {[Co(DPTDC)(bimb)(H2O)]·2DMF}n (Co-MOF-2) (H2DMTDC = 3,4-dimethylthieno[2,3-b]thiophene-2,5-dicarboxylic acid, H2DPTDC = 3,4-diphenylthieno[2,3-b]thiophene-2,5-dicarboxylic acid, bimb = 1,4-bis((1H-imidazol-1-yl)methyl)benzene), were obtained by the reaction of flexible N-containing ligand bimb and two structurally related thiophene-containing ligands H2DMTDC and H2DPTDC, respectively. These Co-MOFs displayed a 3D framework and porous structure, respectively. Co-MOF-1 and the activated sample Co-MOF-2' could act as green heterogeneous catalysts for the one-pot multicomponent Biginelli reaction, specifically the dehydration condensation process involving aldehydes, acetoacetates, and urea to yield dihydropyrimidin-2(1H)-ones. The reaction has advantages such as solvent-free conditions, water as only byproduct, readily accessible starting materials, excellent functional group compatibility, and simple operation. Both catalysts exhibited a wide substrate scope and maintained significant catalytic activity over five cycles. The special catalytic performance may be ascribed to functional groups within the ligand.

Effect of structure on sensing performance of nitro explosives with high sensitivity and mechanism of two Tb(III) coordination polymers

The use of a conjugate N-containing ligand resulted in the decreasing of structural dimensions from 2D network of [Tb(2-pyia)(Ac)(H2O)] (CP1) to 1D chain [Tb(2-pyia)(Ac)(IDP)] (CP2) (2-H2pyia = 5-(pyridin-2-ylmethoxy) isophthalic acid and IDP=imidazo[4,5-f]-[1,10] phenanthroline). Both of them exhibit the characteristic luminescence of Tb ions and could have high fluorescence sensing properties for cefixime and fluridine. The different sensing properties for nitro explosives are manifested as CP1 for nitrobenzene and CP2 for 4-nitrophenol due to the difference in structure. Furthermore, CP2 exhibits the ratiometric fluorescence sensing for Fe3+ ion with a low detection limit of 0.405 μM. The fluorescence sensing mechanism of the two Tb complexes for different analytes was investigated using experimental methods and theoretical calculations. CP1 was used for the detection of Flu residues in the actual system and better results were obtained. The work shows the introduction of the chelated ligand might affect the structural and sensing performance changes of coordination polymers.

Monodentate Phosphinoamine Nickel Complex Supported on a Metal-Organic Framework for High-Performance Ethylene Dimerization.

Ethylene dimerization is an efficient industrial chemical process to produce 1-butene, with demanding selectivity and activity requirements on new catalytic systems. Herein, a series of monodentate phosphinoamine-nickel complexes immobilized on UiO-66 are described for ethylene dimerization. These catalysts display extensive molecular tunability of the ligand similar to organometallic catalysis, while maintaining the high stability attributed to the metal-organic framework (MOF)scaffold. The highly flexible postsynthetic modification method enables this study to prepare MOFs functionalized with five different substituted phosphines and 3 N-containing ligands and identify the optimal catalyst UiO-66-L5-NiCl2 with isopropyl substituted nickel mono-phosphinoamine complex. This catalyst shows a remarkable activity and selectivity with a TOF of 29000 (molethyl/molNi/h) and 99% selectivity for 1-butene under ethylene pressure of 15bar. The catalyst is also applicable for continuous production in the packed column micro-reactor with a TON of 72000 (molethyl/molNi). The mechanistic insight for the ethylene oligomerization has been examined by density functional theory (DFT) calculations. The calculated energy profiles for homogeneous complexes and truncated MOF models reveal varying rate-determining step as β-hydrogen elimination and migratory insertion, respectively. The activation barrier of UiO-66-L5-NiCl2 is lower than other systems, possibly due to the restriction effect caused by clusters and ligands. A comprehensive analysis of the structural parameters of catalysts shows that the cone angle as steric descriptor and butene desorption energy as thermodynamic descriptor can be applied to estimate the reactivity turnover frequency (TOF) with the optimum for UiO-66-L5-NiCl2. This work represents the systematic optimization of ligand effect through combination of experimental and theoretical data and presents a proof-of-concept for ethylene dimerization catalyst through simple heterogenization of organometallic catalyst on MOF.

Hexakis(urea-O)iron Complex Salts as a Versatile Material Family: Overview of Their Properties and Applications.

Due to their Fe- and N-containing reactive urea ligand content, the hexakis(urea-O)iron(II) and hexakis(urea-O)iron(III) complexes were found to be versatile materials in various application fields of industry and environmental protection. In our present work, we have comprehensively reviewed the synthesis, structural and spectroscopic details, and thermal properties of hexakis(urea-O)iron(II) and hexakis(urea-O)iron(III) salts with different anions (NO3-, Cl-, Br- I-, I3-, ClO4-, MnO4-, SO42-, Cr2O72-, and S2O82-). We compared and evaluated the structural, spectroscopic (IR, Raman, UV-vis, Mössbauer, EPR, and X-ray), and thermogravimetric data. Based on the thermal behavior of these complexes, we evaluated the solid-phase quasi-intramolecular redox reactions of anions and urea ligands in these complexes and summarized the available information on the properties of the resulting simple and mixed iron-containing oxides. Furthermore, we give a complete overview of the application of these complexes as catalysts, reagents, absorbers, or agricultural raw materials.

Facile synthesis of nanostructured Ni/NiO/N-doped graphene electrocatalysts for enhanced oxygen evolution reaction.

Electrocatalysts containing a Ni/NiO/N-doped graphene interface have been synthesised using the ligand-assisted chemical vapor deposition technique. NiO nanoparticles were used as the substrate to grow N-doped graphene by decomposing vapours of benzene and N-containing ligands. The method was demonstrated with two nitrogen-containing ligands, namely dipyrazino[2,3-f:2',3'-h]quinoxaline-2,3,6,7,10,11-hexacarbonitrile (L) and melamine (M). The structure and composition of the as-synthesized composites were characterized by XRD, Raman spectroscopy, SEM, TEM and XPS. The composite prepared using the ligand L had NiO sandwiched between Ni and N-doped graphene and showed an overpotential of 292 mV at 10 mA cm-2 and a Tafel slope of 45.41 mV dec-1 for the OER, which is comparable to the existing noble metal catalysts. The composite prepared using the ligand M had Ni encapsulated by N-doped graphene without NiO. It showed an overpotential of 390 mV at 10 mA cm-2 and a Tafel slope of 78.9 mV dec-1. The ligand-assisted CVD route demonstrates a facile route to control the microstructure of the electrocatalysts.

Coordination polymers and supramolecular cages based on [(MS4)Cux]x−2 cluster units and N-containing ligands

This work demonstrates that the number and arrangement of Cu+ around the (MS4)2− core can be varied with the synthesis conditions, affording heterothiometallic [(MS4)Cux]x−2 cluster units with versatile geometries and connectivities for building CPs.

Tailoring two magic number Au13 nanoclusters with N-containing diphosphine ligands: a classical icosahedral core vs. an unprecedented UFO- shaped core

Two magic number Au13 nanoclusters were tailored using two N-containing multidentate phosphine ligands with a classical icosahedral core and an unprecedented “UFO”-shaped polyhedral core, respectively.

Theoretical insights into selective extraction of Am(III) from Cm(III) and Eu(III) with asymmetric N-heterocyclic ligands.

Separation of lanthanide (Ln) and minor actinide (MA) elements and mutual separation between minor actinide elements (e.g. Am(III) and Cm(III)) represent a crucial undertaking. However, separating these elements poses a significant challenge owing to their highly similar physicochemical properties. Asymmetric N-heterocyclic ligands such as N-ethyl-6-(1H-pyrazol-3-yl)-N-(p-tolyl)picolinamide (Et-p-Tol-A-PzPy) and N-ethyl-N-(p-tolyl)-1,10-phenanthroline-2-carboxamide (ETPhenAm) have recently received considerable attention in the separation of MAs over Ln from acid solutions. By changing the central skeleton structures of these ligands and introducing substituents with different properties on the side chains, their complexation behavior with Am(III), Cm(III), and Eu(III) may be affected. In this work, we explore four different asymmetric N-containing heterocyclic ligands, namely Et-p-Tol-A-PzPy (L1), N-ethyl-6'-(1H-pyrazol-3-yl)-N-(p-tolyl)-[2,2'-bipyridine]-6-carboxamide (L2), N-ethyl-9-(1H-pyrazol-3-yl)-N-(p-tolyl)-1,10-phenanthroline-2-carboxamide (L3), and ETPhenAm (L4) using density functional theory (DFT). The calculated results demonstrate the potential of ligands L1-L4 for the extraction and separation of Am(III), Cm(III), and Eu(III). Ligand analysis shows that ligand L3 binds more easily to the central metal atom, in line with the stronger extraction capacity of L3. In spite of the higher covalence between the side chain and the central metal atom for complexes with L1-L3, the main chain seems to control the stability of the extraction complexes. The preorganized 1,10-phenanthroline backbone also further enhances the extraction performance of L3 and L4. The difference in coordination ability between the side chain donors of these ligands and metal ions may affect their separation efficiency. This work presents theoretical insights into synthesizing novel ligands for separating trivalent actinides by adjusting N-heterocyclic ligands.

Enhancing visual fluorescence detection of tetracycline antibiotics through nitrogen containing ligand regulation and antenna effect of Ln3+

Two fluorescent Cd-MOFs were obtained by solventhermal process using flexible carboxylic acid ligand of 4-(3,5-dicarboxylatobenzyloxy) benzoic acid (H3L) and flexible/rigid tripodal N-containing ligand 1,3,5-tris(1,2,4-tiazol-1-ylmethyl)-2,4,6-Trimethylbenzene (ttytb) and 2,4,6-tris(4-pyridyl)-1,3,5-triazine(tpytz), namely, {[Cd(HL)(ttytb)]·DMF·3H2O}n (LCU-127)...

Some remarks on the biological application of gold(III) complexes.

Gold(III) complexes are widely studied as antitumor agents and show good results. The interaction with biologically active thiols (thiomalate, cysteine, glutathione (GSH) and human serum albumin) of a number of gold(III) complexes with N-containing polydentate ligands in aqueous solution with pH 7.4 and 0.2M NaCl was studied. Complexes with 1,10-phenanthroline and 2,2'-bipyridyl, Au(phen)(OH)2+ and Au(bipy)(OH)2+, react fast with an excess of any of these thiols and in less than a few seconds transform into gold(I) bis-thiolate complexes. For complexes with deprotonated ethylenediamine and diethylenetriamine, Au(en)(en-H)2+ and Au(dien-H)(Cl,OH)+, at a significant excess of GSH, a relatively long-lived gold(III) complex AuIII(GSH)iLj is formed. At t = 37°C, it transforms into the gold(I) bis-thiolate complex Au(GSH)2 by 90% in 4h. However, for other thiols, the rate of decomposition of similar complexes is about 10 times higher. Some other complexes were also considered. In all cases, a fairly fast reduction of gold(III) to gold(I) occurs with the formation of the gold(I) bis-thiolates.

Ligand-Aided Glycolysis of PET Using Functionalized Silica-Supported Fe2O3 Nanoparticles.

The development of efficient catalysts for the chemical recycling of poly(ethylene terephthalate) (PET) is essential to tackling the global issue of plastic waste. There has been intense interest in heterogeneous catalysts as a sustainable catalyst system for PET depolymerization, having the advantage of easy separation and reuse after the reaction. In this work, we explore heterogeneous catalyst design by comparing metal-ion (Fe3+) and metal-oxide nanoparticle (Fe2O3 NP) catalysts immobilized on mesoporous silica (SiO2) functionalized with different N-containing amine ligands. Quantitative solid-state nuclear magnetic resonance (NMR) spectroscopy confirms successful grafting and elucidates the bonding mode of the organic ligands on the SiO2 surface. The surface amine ligands act as organocatalysts, enhancing the catalytic activity of the active metal species. The Fe2O3 NP catalysts in the presence of organic ligands outperform bare Fe2O3 NPs, Fe3+-ion-immobilized catalysts and homogeneous FeCl3 salts, with equivalent Fe loading. X-ray photoelectron spectroscopy analysis indicates charge transfer between the amine ligands and Fe2O3 NPs and the electron-donating ability of the N groups and hydrogen bonding may also play a role in the higher performance of the amine-ligand-assisted Fe2O3 NP catalysts. Density functional theory (DFT) calculations also reveal that the reactivity of the ion-immobilized catalysts is strongly correlated to the ligand-metal binding energy and that the products in the glycolysis reaction catalyzed by the NP catalysts are stabilized, showing a significant exergonic character compared to single ion-immobilized Fe3+ ions.

Four novel coordination compounds based on N-acetyl-L-phenylalanine: Synthesis, characterization and fluorescence properties

Four novel d10 transition metal chiral coordination compounds Cd(L-acphe)2(H2O)2 (1), {[Cd(L-acphe)2(bpe)(H2O)]·2·5H2O}n (2), {[Cd(L-acphe)2 (4,4′-bipy)(H2O)]·H2O}n (3), {[Zn2(L-acphe)2(bpp)2(OH)]NO3·2H2O}n (4) (L-Hacphe = N-acetyl-l-phenylalanine, 4,4′-bipy = 4,4′-bipyridine, bpe = 1,2-bis (4-pyridyl)ethane, bpp = 1,3-bis(4-pyridyl)propane) have been synthesized by changing central metal ions and N-containing auxiliary ligands. Their structures were determined by single crystal X-ray diffraction analysis and characterized by elemental analysis, infrared spectroscopy, thermogravimetric analysis, powder X-ray diffraction and circular dichroism. The structures of compounds 1–3 with cadmium(Ⅱ) as the center metal ion change from 0D, 1D to 2D, ultimately compound 1 generates a 2D supramolecular structure via hydrogen bonding, while compounds 2 and 3 expand to 3D supramolecular structures through hydrogen bonding. The compound 4 with zinc(Ⅱ) as the center metal ion feature 1D chain structures, and 3D supramolecular structure of compound 4 is formed by hydrogen bonding. The present results indicate that selecting central metals with different electronic structures and introducing different N-containing auxiliary ligands could achieve the regulation of the structures of compounds. In addition, the fluorescence recognition properties of compounds 3 and 4 demonstrate that they can highly selectively detect Fe3+ and nitrobenzene in aqueous solutions through fluorescence quenching, indicating that compounds 3 and 4 are expected to become bifunctional fluorescence recognition sensors for the detection of Fe3+ ions and nitrobenzene.

Theoretical Study on the Coordination and Separation Capacity of Macrocyclic N-Donor Extractants for Am(III)/Eu(III).

Designing ligands that can effectively separate actinide An(III)/lanthanide Ln(III) in the solvent extraction process remains one of the key issues in the treatment of accumulated spent nuclear fuel. Nitrogen donor ligands are considered as promising extractants for the separation of An(III) and Ln(III) due to their environmental friendliness. Four new macrocyclic N-donor hexadentate extractants were designed and their coordination with Am(III) and Eu(III), as well as their extraction selectivity and separation performance for Am(III) and Eu(III), were investigated by scalar relativistic density functional theory. A variety of theoretical methods have been used to evaluate the properties of the four ligands and the coordination structures, bonding properties, and thermodynamic properties of the complexes formed by the four ligands with Am(III) and Eu(III). The results of various wavefunction analysis methods including NBO analysis, quantum theory of atoms in molecules (QTAIM) analysis, and so on show that Am(III) has a stronger coordination ability with the ligands than Eu(III) due to the Am 5f orbitals more involved in bonding with the ligands than the Eu 4f orbitals, and the bonding environment of the N-donor in the ligand has a significant effect on its coordination ability of the metal ions. Thermodynamic analysis of the solvent extraction process shows that all of the four N-containing macrocyclic ligands have good extraction selectivity and separation performance for Am(III) and Eu(III). This study provides theoretical support for designing potential nitrogen-containing macrocyclic extractants with excellent separation performance.

A highly stable Sr(II) dimer bearing phenyl carboxylate and N-containing ligands: Synthesis, crystal structure and proton conduction

Investigating the proton conductivity of crystalline materials based on supramolecular complexes holds important promise for application. Based on this, we prepared a novel three-dimensional supramolecular complex, [Sr2(dcba)4(phen)2(H2O)4] (1) based on a binuclear structural unit using the hydrothermal reaction of 3,4-dichlorobenzoic acid (H2dcba) and 1,10-phenanthroline (phen) with strontium chloride. Its crystal structure of 1 was first characterized, and its good H2O and thermal stability were further investigated, and its proton conductivity was temperature- and humidity-dependent. The analysis of the conductive mechanism indicated the presence of abound H-bonding networks within the solid-state structure, which facilitated the migration of protons.

Analysis of Radioactive Iodine Trapping Mechanism by Zinc-Based Metal-Organic Frameworks with Various N-Containing Carboxylate Ligands.

This study aimed to develop effective adsorbents for capturing radioactive iodine in nuclear power waste gas. Two zinc metal-organic frameworks (Zn-MOFs) were synthesized and found to have favorable properties such as a large surface area, thermal stability, surface rich in π-electron-containing nitrogen, and redox potential. Adsorption experiments revealed maximum capacities of 1.25 and 1.96 g g-1 for the MOFs at 75 °C, with the pseudo-second-order kinetic model fitting the data well. The Langmuir equation provided a better fit in cyclohexane, with maximum adsorption amounts of 249 and 358 mg g-1 for Zn-MOF-1 and Zn-MOF-2, respectively. The MOFs were also stable during six cycles of adsorption and desorption. Furthermore, electron transfer occurred due to the synergistic adsorption of Zn, N, and O atoms, resulting in the conversion of some iodine to polyiodide. Zn-MOF-2 exhibited better chemisorption than Zn-MOF-1 due to a smaller highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) gap. Notably, it was discovered that N-containing radicals had stronger interactions with iodine compared to radicals without N. These findings provide valuable insights into MOF synthesis and environmental protection.

Nicotianamine: A Key Player in Metal Homeostasis and Hyperaccumulation in Plants

Nicotianamine (NA) is a low-molecular-weight N-containing metal-binding ligand, whose accumulation in plant organs changes under metal deficiency or excess. Although NA biosynthesis can be induced in vivo by various metals, this non-proteinogenic amino acid is mainly involved in the detoxification and transport of iron, zinc, nickel, copper and manganese. This review summarizes the current knowledge on NA biosynthesis and its regulation, considers the mechanisms of NA secretion by plant roots, as well as the mechanisms of intracellular transport of NA and its complexes with metals, and its role in radial and long-distance metal transport. Its role in metal tolerance is also discussed. The NA contents in excluders, storing metals primarily in roots, and in hyperaccumulators, accumulating metals mainly in shoots, are compared. The available data suggest that NA plays an important role in maintaining metal homeostasis and hyperaccumulation mechanisms. The study of metal-binding compounds is of interdisciplinary significance, not only regarding their effects on metal toxicity in plants, but also in connection with the development of biofortification approaches to increase the metal contents, primarily of iron and zinc, in agricultural plants, since the deficiency of these elements in food crops seriously affects human health.

A stable N-containing heterocyclic carboxylic acid ligand Co-MOF for photoelectric performance and anionic dyes adsorption

Metal-organic frameworks (MOFs) are crystalline porous hybrid materials with periodic network structure and abundant active sites, which are promising adsorbents for organic pollutants. Herein, a novel Co(II)-based organic framework (Co-MOF) [Co2(L1)2(L2)] (L1 = 3-(3-carboxylphenyl) isonicotinic acid, L2 = 4, 4′-Azopyridin) was developed for selective dyes adsorption. Experiments suggest that the Co-MOF exhibits high stability, good photoelectricity and high selectivity for dyes adsorption. For dyes adsorption, the Co-MOF shows a strong adsorption to methyl orange achieving a high capacity up to 440.5 mg g−1, but shows a weak adsorption to methylene blue or rhodamine, indicating its better selectivity for anionic dyes. An insight into the selective removal of the methyl orange is being accounted for by acid-base attraction, anion-π and π–π stacking interactions, involving the Co ion, phenyl rings, and ocarboxylate of L, and the phenyl rings, and osulfonate of MO. The current work contributes to the development of future multifunctional MOF materials with the application in environment protection.

Synthesis, Structure, and Magnetic Properties of Two {Co16IICo4III} Supertetrahedral T4 Clusters Formed from the In Situ Dissociation of a Tertiary N-Containing Ligand

Two mixed-valent cobalt clusters {[(CoII)16(CoIII)4(μ6-O)4(μ3-OH)12(OCH3)12(H2O)8(BMBC)4]·(NO3)8} (1) and {[(CoII)16(CoIII)4(μ3-OH)20(OCH2CH3)4(HOCH2CH3)8(BMBC)4]·(NO3)8} (2) were synthesized and constructed by a semiflexible dicarboxylic ligand 4′,4′-[ammoniobis(methylene)]-bis[(1,1′-biphenyl)-2-carboxylate] (BMBC–) with Co(NO3)2·6H2O under solvothermal systems. Interestingly, the ligand BMBC- is afforded from the in situ dissociation reaction of tertiary N-containing organic carboxylic acid ligands. The complexes present a beautiful supertetrahedral T4 cluster formed by an interior Co4IIIO4 cubane and four exterior Co4IIO4 cubanes bridged via μ6-O2 and μ3-OH– ions and stabilized by four BMBC– organic ligands. The complexes were confirmed by single-crystal X-ray diffraction (XRD), elemental analysis, infrared spectroscopy, and thermogravimetric analysis. Furthermore, the magnetic analyses reveal that the [Co20] cluster exhibits an antiferromagnetic behavior.

A theoretical study on the influence of N-containing heterocyclic ligands on the luminescence mechanisms (phosphorescence or TADF) of Au (III) complexes

Au (III) complexes display remarkable emission properties in OLEDs materials due to the high-performance emitters in recent years. Explaining microscopic mechanisms of the luminescence process clearly remain a challenge. The intersystem crossing between the singlet excited state and the triplet excited state in the metal complexes systems plays a central role in determining the fate of excitons and various luminescence pathways. For the planar tridentate coordination complexes of Au (III), it remains unclear what are the key factors that affect the luminescent pathways and thus the quantum efficiency. This work uncovers the relationship between the intersystem crossing processes (include ISC and RISC) and electronic structures of chelated ligands in the Au ( III ) complexes, which is supported by the quantum-chemical calculations. It is found that the modification of strong electron-donating groups (such as –NMe 2 , -NPh 2 ) may reduce the vibration coupling effect and energy gap (Δ E ST ), then open the thermal equilibrium channel, and finally obtain higher quantum yield TADF emitter through the fluorescence process. But the complex that has carbazole group in the auxiliary ligand still can't undergo the RISC process. These may be caused by the various electron delocalization and transition type result from different auxiliary ligands mediated by the N 2 atom. Moreover, the vibration analyses for the phosphorescence emision show that the vibration modes, which make significantly contribute to the reorganization energy, mainly come from the CˆNˆC ligand. While for TADF emission, that is from the auxiliary ligand. This work presents a deep insight into the luminescent mechanism and the key factors affected by the regulation of the ligands in the Au (III) complexes, and provides valuable theoretical basis and reference for the synthesis and design of TADF materials. • The higher SOC effect does not necessarily lead to the TADF process. • The modification of strong electron-donating may reduce the vibration coupling effect and energy gap Δ E ST , finally obtain higher quantum yield TADF emitter through the fluorescence process. • Adding the carbazole group in the auxiliary ligand can enhance the contribution of the CˆNˆC ligand on the reorganization energy.

Two Co-Based Metal–Organic Framework Isomers with Similar Metal-Carboxylate Sheets: Turn-On Ratiometric Luminescence Sensing Activities toward Biomarker N-Acetylneuraminic Acid and Discrimination of Ga3+ and In3+

Two supramolecular Co-MOF isomers, namely, {[Co(L)0.5(m-bimb)]·3H2O}n (LCU-115) and {[Co(L)0.5(p-bimb)]·3H2O}n (LCU-116), were synthesized from an amide-containing carboxylic acid N,N″-(3,5-dicarboxylphenyl)benzene-1,4-dicarboxamide (H4L) and two flexible positional isostructural N-containing ligands m-bimb and p-bimb (m-bimb = 1,3-bis((1H-imidazol-1-yl)methyl)benzene; p-bimb = 1,4-bis((1H-imidazol-1-yl)methyl)benzene). The carboxylate ligands connect Co(II) centers to form 2D metal-carboxylate sheets, which are extended further by m-bimb and p-bimb to form a 2D bilayer with parallel stacking (LCU-115) and a 3D framework (LCU-116), respectively. Luminescence measurements indicated that these two complexes exhibited interesting multiresponsive sensing activities toward pH, biomarker N-acetylneuraminic acid, and trivalent cations Ga3+/In3+. They show highly sensitive turn-on fluorescence responses in the acidic range and can also be regarded as on-off-on vapoluminescent sensors to typical acidic and basic gases HCl and Et3N. It is worth noting that these complexes have excellent turn-on ratiometric fluorescence sensing ability for N-acetylneuraminic acid (NANA) with detection limits as low as 7.39 and 8.06 μM, respectively. Furthermore, they were successfully applied for the detection of NANA in simulated urine and serum samples with satisfactory results. For ion detection, LCU-116 could detect both Ga3+ and In3+, while LCU-115 could distinguish Ga3+ from In3+ with the latter showing luminescence quenching. The sensing mechanism was investigated in detail by XRD, UV-vis, EDS, XPS, SEM, and TEM. The results of interday and intraday precision studies gave low RSD values in the range of 1.19-3.53%, ascertaining the reproducibility of these sensors. The recoveries for the sensing analytes in simulated urine/serum or real water are satisfactory from 96.7 to 103.3% (toward NANA) and 96.6 to 115.0% (toward Ga3+ and In3+), indicating that these two complexes also possess acceptable reliability for monitoring in real samples. The results indicated that the supramolecular isomers LCU-115 and LCU-116 are promising material candidates for application in biological and environmental monitoring.