The Stability of Metal N,N,N′,N′‐Tetrakis(2‐aminoethyl)ethane‐ 1,2‐diamine (=penten) Complexes and the X‐Ray Crystal Structure of [Tl(NO3)(penten)](NO3)2

Complex formation between N,N,N′,N′‐tetrakis(2‐aminoethyl)ethane‐1,2‐diamine (penten) and the metal ions Mn²⁺, Co²⁺, Cu²⁺, Zn²⁺, Cd²⁺, Hg²⁺, Ag⁺, Pb²⁺, and Tl³⁺ (in 1.00M NaNO₃ and 25°) was investigated by potentiometry and spectrophotometry. These are the first reported values of the stability constants for this ligand with Ag⁺, Pb²⁺, and Tl³⁺. The X‐ray crystal structure of [Tl(NO₃)(penten)](NO₃)₂ was determined. In this structure, Tl³⁺ shows a coordination number of seven made up of the six N‐donors and one O‐atom of NO.     

Quenching effect of some heavy metal ions on the fast peroxyoxalate-chemiluminescence of 1-(dansylamidopropyl)-1-aza-4,7,10-trithiacyclododecane as a novel fluorophore

The fast chemiluminescence (CL) arising from the reaction of bis(2,4,6-trichlorophenyl)oxalate (TCPO) with hydrogen peroxide in the presence of 1-(dansylamidopropyl)-1-aza-4,7,10-trithiacyclododecane (L) as a novel fluorophore, and imidazole as catalyst, has been studied in ethyl acetate solution. The relationships between the chemiluminescence intensity and concentrations of TCPO, imidazole, hydrogen peroxide and L are reported. In the presence of imidazole as catalyst, the entire CL signal was completed in less than 3 s. The quenching effect of Cu²⁺, Pb²⁺, Cd²⁺, Hg²⁺ and Ag⁺ ions on the chemiluminescent system was investigated, the resulting Stern–Volmer plots were obtained and the K_Q values were calculated. It was found that the quenching effect of metal ions on the chemiluminescence of L decreases in the order Cu²⁺ > Pb²⁺ > Cd²⁺ > Hg²⁺ > Ag⁺.     

Eco‐friendly Sensors Developed by Herbal Based Silver Nanoparticles for Electrochemical Detection of Mercury (II) Ion

In our study, the single‐use & eco‐friendly electrochemical sensor platform based on herbal silver nanoparticles (AgNPs) was developed for detection of mercury (II) ion (Hg²⁺). For this purpose, the surface of pencil graphite electrode (PGE) was modified with AgNPs and folic acid (FA), respectively. The concentrations of AgNPs and FA were firstly optimized by differential pulse voltammetry (DPV) to obtain an effective surface modification of PGE. Each step at the surface modification process was characterized by using cyclic voltammetry (CV) and electrochemical impedence spectroscopy (EIS). The limit of detection (LOD) for Hg²⁺ was estimated and found to be 8.43 μM by CV technique. The sensor presented an excellent selectivity for Hg²⁺ against to other heavy metal ions such as Ca²⁺, Cd²⁺, Cr³⁺, Cu²⁺, Mg²⁺, Ni²⁺, Pb²⁺, Zn²⁺, Co²⁺ and Mn²⁺. Moreover, a rapid, selective and sensitive detection of Hg²⁺ was successfully performed in the samples of tap water within 1 min.     

High-sensitivity determination of lead and cadmium based on the Nafion-graphene composite film

Graphene nanosheets, dispersed in Nafion (Nafion-G) solution, were used in combination with in situ plated bismuth film electrode for fabricating the enhanced electrochemical sensing platform to determine the lead (Pb²⁺) and cadmium (Cd²⁺) by differential pulse anodic stripping voltammetry (DPASV). The electrochemical properties of the composite film modified glassy carbon electrode were investigated. It is found that the prepared Nafion-G composite film not only exhibited improved sensitivity for the metal ion detections, but also alleviated the interferences due to the synergistic effect of graphene nanosheets and Nafion. The linear calibration curves ranged from 0.5 μg L⁻¹ to 50 μg L⁻¹ for Pb²⁺ and 1.5 μg L⁻¹ to 30 μg L⁻¹ for Cd²⁺, respectively. The detection limits (S/N = 3) were estimated to be around 0.02 μg L⁻¹ for Pb²⁺ and Cd²⁺. The practical application of the proposed method was verified in the water sample determination.     

Syntheses,Structures and Characterization of Four Metal‐Organic Frameworks constructed by 2,2′,6,6′‐Tetramethoxy‐4,4′‐biphenyldicarboxylic Acid

Four metal‐organic frameworks (MOFs), {[Mn_3.5L(OH)(HCOO)₄(DMF)] · H₂O} ( 1 ), {[In_2.5L₂O(OH)_1.5(H₂O)₂] · DMF · CH₃CN · 2H₂O} ( 2 ), {[Pb₄L₃O(DMA)] · CH₃CN} ( 3 ), and {[LaL(NO₃)(DMF)₂] · 2H₂O} ( 4 ) were synthesized by utilizing the ligand 2,2′,6,6′‐tetramethoxy‐4,4′‐biphenyldicarboxylic acid (H₂L) via solvothermal methods. All MOFs were characterized by single‐crystal X‐ray diffraction, powder X‐ray diffraction, thermogravimetric analysis, and infrared spectroscopy. In 1 , the Mn²⁺ ions are interconnected by formic groups in situ produced via DMF decomposition to form a rare 2D macrocyclic plane, which is further linked by L^2– to construct the final 3D network. In 2 , 1D zip‐like infinite chain is formed and then interconnected to build the 3D framework. In 3 , a [Pb₆(μ₄‐O)₂(O₂C)₁₀(DMA)₂] cluster with a centrosymmetric [Pb₆(μ₄‐O)₂]⁸⁺ octahedral core is formed in the 3D structure. In 4 , the La³⁺ ions are connected with each other through carboxylate groups of L^2– to generate 1D zigzag chain, which is further linked by L^2– to construct a 3D network with sra topology. Solid photoluminescence properties of 3 and 4 were also investigated.     

Calix[4]Resorcinarene Macrocycles Interactions with Cd2+, Hg2+, Pb2+, and Cu2+ Cations: A QCM‐I and Langmuir Ultra‐thin Monolayers Study

Stable ultra‐thin Langmuir monolayers of calix[4]resorcinarene derivatives, namely: C‐dec‐9‐enylcalix[4]resorcinarene‐O‐(R+)‐α‐methylbenzylamine (Ionophore I ), and C‐dec‐9‐enylcalix[4]resorcinarene‐O‐(S‐)‐α‐methylbenzylamine (Ionophore II ), were prepared at the air‐water interface. Their interactions with a series of heavy metals (HM) ions (Cu²⁺, Pb²⁺, Hg²⁺ and Cd²⁺) present in the aqueous subphase were investigated by measuring surface pressure‐area isotherms, at different concentrations. The surface pressure‐area (Π‐A) isotherms were stable and demonstrated the HM amounts influence on the limiting area (A_lim) values, therefore confirming the examined macrocycles capability to host the metallic toxicants. Additionally, a HM concentration dependence was realized and interpreted by a selective tendency of both ionophores towards Cu²⁺ and Cd²⁺ ions over Pb²⁺ and Hg²⁺, especially at high concentrations. The HM ions interactions with the applied calix[4]resorcinarene Langmuir ultra‐thin monolayers were interpreted based on the Gibbs‐Shishkovsky adsorption equation. Moreover, quartz crystal microbalance with impedance measurement (QCM‐I), was applied for the detection of HM ions in solutions. The QCM‐I results showed the effectiveness of the coated QCM‐I crystals in detecting the ions at different concentrations. The detection limit values were in the order of 0.16, 0.3, 0.65, 1.1 ppm (Ionophore I), as well 0.11, 0.45, 0.2, 0.89 (Ionophore II) for the Cu²⁺, Pb²⁺, Hg²⁺ and Cd²⁺ cations, respectively. Additionally, a selective tendency of both ionophores towards copper ions was shown.     

Determination of Trace Lead and Cadmium in Water Samples by Anodic Stripping Voltammetry with a Nafion‐Ionic Liquid‐Coated Bismuth Film Electrode

A new chemically modified bismuth film electrode coated with an ionic liquid [(1‐ethyl‐3‐methylimidazolium tetracyanoborate (EMIM TCB)] and Nafion was developed for the simultaneous determination Pb²⁺ and Cd²⁺ by anodic stripping voltammetry. Compared with conventional bismuth film electrodes, this electrode exhibited greatly improved electrochemical activity for Pb²⁺ and Cd²⁺ detection due to the unique properties of Nafion polymer and ionic liquid. The key experimental parameters related to the fabrication of the electrode and the voltammetric measurements were optimized on the basis of the stripping signals, where the peak currents increased linearly with the metal concentrations in a range of 10–120 µg L^?1 with a detect limit of 0.2 µg L^?1 for Pb²⁺, and 0.5 µg L^?1 for Cd²⁺ for 120s deposition. High reproducibility was indicated from the relative standard deviations (1.9 and 2.5 %) for nine repetitive measurements of 20 µg L^?1 Pb²⁺ and Cd²⁺, respectively. In addition, the surface characteristics of the modified BiFE were investigated by scanning electron microscopy (SEM), and results showed that fibril‐like bismuth nanostructures were formed on the porous Nafion polymer matrix. Finally, the developed electrode was applied to determine Pb²⁺ and Cd²⁺ in water samples, indicating that this electrode was sensitive, reliable and effective for the simultaneous determination of Pb²⁺ and Cd²⁺.     

Syntheses,structures of N‐(substituted)‐2‐aza‐[3]‐ferrocenophanes and their application as redox sensor for Cu2+ ion

Rigid N‐(substituted)‐2‐aza‐[3]‐ferrocenophanes L1 and L2 were easily synthesized from 1,1 ‐dicarboxyaldehydeferrocene and the corresponding amines. Ligands L1 and L2 were characterized by ¹H NMR, ¹³C NMR and single‐crystal X‐ray crystallography. The coordination abilities of L1 and L2 with metal ions such as Cu²⁺, Mg²⁺, Ni²⁺, Zn²⁺, Pb²⁺ and Cd²⁺ were evaluated by cyclic voltammetry. The electrochemical shift (ΔE_1/2) of 125 mV was observed in the presence of Cu²⁺ ion, while no significant shift of the Fc/Fc + couple was observed when Mg²⁺, Ni²⁺, Zn²⁺, Pb²⁺, Cd²⁺ metal ions were added to the solution of L1 in the mixture of MeOH and H₂O. Moreover, the extent of the anodic shift of redox potentials was approximately equal to that induced by Cu²⁺ alone when a mixture of Cu²⁺, Mg²⁺, Ni²⁺, Zn²⁺, Pb²⁺ and Cd²⁺ was added to a solution of L1. Ligand L1 was proved to selectively sense Cu²⁺ in the presence of large, excessive first‐row transition and late‐transition metal cations. The coordination model was proposed from the results of controlled experiments and quantum calculations. Copyright © 2012 John Wiley & Sons, Ltd.     

A novel cadmium(II) coordination polymer with biphenyl‐3,3′,4,4′‐tetra­carboxylic acid and 4,4′‐bipyridine

A novel cadmium(II) coordination polymer, poly[[[bis­(4,4′‐bipyridine)cadmium(II)]‐μ₃‐4,4′‐dicarboxy­biphenyl‐3,3′‐di­carboxyl­ato] 0.35‐hydrate], {[Cd(C₁₆H₈O₈)(C₁₀H₈N₂)₂]·0.35H₂O}_n, was obtained by reaction of Cd(CH₃COO)₂·3H₂O, 4,4′‐bipyridine (4,4′‐bpy) and biphenyl‐3,3′,4,4′‐tetra­car­boxylic acid (H₄L) under hydro­thermal conditions. Each Cd^II atom lies at the centre of a distorted octa­hedron, coordinated by four O atoms from three H₂L²⁻ ligands and N atoms from two monodentate 4,4′‐bpy ligands. Each H₂L²⁻ ligand coordinates to three Cd^II atoms through two carboxyl­ate groups, one acting as a bridging bidentate ligand and the other in a chelating bidentate fashion. Two Cd atoms, two H₂L²⁻ anions and four 4,4′‐bpy ligands form a ring dimer node, which links into an extended broad zonal one‐dimensional chain along the c axis.     

Poly[(N,N‐dimethylformamide‐κO)(μ3‐4,4′‐ethylenedibenzoato‐κ5O,O′:O′:O′′,O′′′)(pyrazino[2,3‐f][1,10]phenanthroline‐κ2N8,N9)lead(II)]

In the title Pb^II coordination polymer, [Pb(C₁₆H₁₀O₄)(C₁₄H₈N₄)(C₃H₇NO)]_n, each Pb^II atom is eight‐coordinated by two chelating N atoms from one pyrazino[2,3‐f][1,10]phenanthroline (L) ligand, one dimethylformamide (DMF) O atom and five carboxylate O atoms from three different 4,4′‐ethylenedibenzoate (eedb) ligands. The eedb dianions bridge neighbouring Pb^II centres through four typical Pb—O bonds and one longer Pb—O interaction to form a two‐dimensional structure. The C atoms from the L and eedb ligands form C—H...O hydrogen bonds with the O atoms of eedb and DMF ligands, which further stabilize the structure. The title compound is the first Pb^II coordination polymer incorporating the L ligand.     

Conductometric studies and application of new Schiff base ligand as carbon paste electrode modifier for mercury and cadmium determination

A new chemically modified carbon paste electrode by 2,2?-((pyridine-2,6-diylbis(azanylylidene))bis(methanylylidene))diphenol (L) ligand has been made and used as a sensor for determination of trace mercury and cadmium ions with cyclic voltammetry (CV) and differential pulse voltammetry (DPV) methods. Complexation studies of the ligand with Cu²⁺, Zn²⁺, Hg²⁺, Ni²⁺ and Cd²⁺ ions by conductometric method in acetonitrile–ethanol mixture at 25°C show that the ML complexes have formed. The formation constants of complexes were calculated from the computer fitting of the molar conductance–mole ratio data, and the stability of the resulting complexes varied in order of Cd²⁺ > Hg²⁺ > Cu²⁺ > Zn²⁺ > Ni²⁺. Then a simple and effective chemically modified carbon paste electrode with L was prepared, and the electrochemical properties and applications of the modified electrode were investigated. Under the optimal conditions, the detection limit was 0.0494 μg L^?1 and 0.0782 μg L^?1 for cadmium and mercury ions, respectively, and the linear range for both metal ions were from 1 to 100 μg L^?1. The electrode shows high sensitivity, reproducibility and low cost, and was successfully applied to determination of Cd²⁺ and Hg²⁺ ions in water samples with recovery in the range of 97–101%.     

Improved sensitivity for some [corrected] metal ions by use of sulfide in the Belousov-Zhabotinskii oscillating reaction

A highly sensitive method for the determination of trace amounts of transition metal ions by use of sulfide in the Belousov-Zhabotinskii (B-Z) oscillating chemical reaction is proposed. The use of sulfide increased strongly the sensitivity of the B-Z reaction for transition metal ions, such as Ag⁺, Pb²⁺, Hg²⁺, Cd²⁺, Cu²⁺,and Bi³⁺. Results showed that the variational ratio of oscillating period (P_R) is linearly proportional to the negative logarithm of concentration of metal ions. The detection limit is down to 10⁻¹² mol L⁻¹. Various influencing factors on the determination were also examined.     

Metal ion complexation in acetonitrile by upper-rim allyl-substituted, di-ionized calix[4]arenes bearing two dansyl fluorophores

The influence of Li⁺, Na⁺, K⁺, Rb⁺, Cs⁺, Mg²⁺, Ca²⁺, Sr²⁺, Ba²⁺, Ag⁺, Cd²⁺, Co²⁺, Fe²⁺, Hg²⁺, Mn²⁺, Pb²⁺, Zn²⁺ and Fe³⁺ on the spectroscopic properties of two dansyl (1-dimethylaminonaphthalene-5-sulfonyl) groups linked to the lower rims of a series of three, structurally related, di-ionized calix[4]arenes is investigated by means of absorption and emission spectrophotometry. Di(tetramethylammonium) salts of the di-ionized ligands, L, L1, and L2, which differ in having no, two and four allyl groups, respectively, on the upper rim of the calix[4]arene scaffold, are utilized for the spectrofluorimetric titration experiments in MeCN. On complexation by alkaline earth metal cations, the emission spectra undergo marked red shifts and quenching of the dansyl fluorescence. These effects are weaker with alkali metal cations. Transition metal cations and Pb²⁺ interact strongly with the ligands. In particular, Fe³⁺, Hg²⁺ and Pb²⁺ cause greater than 99% quenching of the dansyl fluorescence.     

In-situ electrochemical and piezogravimetric studies on the application of macrocyclic resorcinarene tetramer in the development of chemically-modified heavy metals ions detection platform in aqueous media

The new application of C-dec-9-enylcalix[4]resorcinarene (R₁), as an ionophore to detect heavy metals (HMs) cations (Cd²⁺, Hg²⁺, Cu²⁺, and Pb²⁺) in the aqueous media has been investigated through the preparation of an effective mass-sensitive sensor via the exploitation of a flow-type QCM-I technique. By adjusting the ions’ amounts in model solutions over a wide range of concentrations, acquired changes in the oscillating frequency related to the loading of metal ions on the sensor’s surface were gained, and thus favorable metrological parameters displaying the lowest detection limit (LOD) associated with copper ions (10 ppb). Simultaneously, a novel voltammetric sensor was prepared by modifying gold screen-printed electrodes (SPEs) with R₁. Electrochemical characterization employing CV, SWV, and EIS was carried out, showing the success of the electrode modification. Then, the experimental conditions of supporting electrolyte, pH, accumulation time, and accumulation potential were optimized to achieve an enhanced detection. The R₁@SPE sensor simultaneously detected the HMs (Cd²⁺, Hg²⁺, Cu²⁺, Pb²⁺), and the lowest LOD was associated with Pb²⁺ (0.19 ppb). The selectivity evaluation of the electrochemical sensor was performed by studying the effect of interferences majorly present in water sources (Mg²⁺, Ni²⁺, Zn²⁺, Al³⁺, and K⁺) on the SWV detection signals, and it was revealed that the interfering ions did not affect the simultaneous detection of the studied HMs (RSD less than 5%), the voltammetric sensors also presented excellent repeatability and reproducibility (RSD less than 5%).     

All Solid State Chromium(III) Selective Potentiometric Sensor Based on 2‐(1‐(2‐((3‐(2‐Hydroxyphenyl)‐1H‐pyrozol‐1‐yl)methyl)benzyl)‐1H‐pyrazol‐3‐yl)phenol

Highly selective all solid state electrochemical sensor based on a synthesized compound i.e. 2‐(1‐(2‐((3‐(2‐hydroxyphenyl)‐1H‐pyrozol‐1‐yl)methyl)benzyl)‐1H‐pyrazol‐3‐yl)phenol (I) as an ionophore has been prepared and investigated for the selective quantification of chromium(III) ions. The effect of various plasticizers, viz. dibutyl phosphonate (DBP), dibutyl(butyl) phosphonate (DBBP), nitrophenyl octyl ether (NPOE), tris‐(2‐ethylhexyl)phosphonate (TEP), tri‐butyl phosphonate (TBP), dioctyl phthalate (DOP), dioctyl sebacate (DOS), benzyl acetate (BA) and acetophenone (AP) along with anion excluders NaTPB (sodium tetraphenyl borate) and KClTPB (potassium(tetrakis‐4‐chlorophenyl)borate was also studied. The optimum composition of the best performing membrane contained (I):KClTPB:NPOE:PVC in the ratio 15 : 3 : 40 : 42 w/w. The sensor exhibited near Nernstian slope of 20.1±0.2 mV/decade of activity in the working concentration range of 1.2×10^?7–1.0×10^?1 M, and in a pH range of 3.8–4.5. The sensor exhibited a fast response time of 10 s and could be used for about 5 months without any considerable divergence in potentials. The proposed sensor showed very good selectivity over most of the common cations including Na⁺, Li⁺, K⁺, Cu²⁺, Sr²⁺, Ni²⁺, Co²⁺, Ba²⁺, Hg²⁺, Pb²⁺, Zn²⁺, Cs⁺, Mg²⁺, Cd²⁺, Al³⁺, Fe³⁺and La³⁺. The activity of Cr(III) ions was successfully determined in the industrial waste samples by using this sensor.     

Competitive heavy metal removal by poly(2‐acrylamido‐2‐methyl‐1‐propane sulfonic acid‐co‐itaconic acid)

The competitive removal of Pb²⁺, Cu²⁺, and Cd²⁺ ions from aqueous solutions by the copolymer of 2‐acrylamido‐2‐methyl‐1‐propane sulfonic acid (AMPS) and itaconic acid (IA), P(AMPS‐co‐IA), was investigated. Homopolymer of AMPS (PAMPS) was also used to remove these ions from their aqueous solution. In the preparation of AMPS–IA copolymer, the molar percentages of AMPS and IA were 80 and 20, respectively. In order to observe the changes in the structures of polymers due to metal adsorption, FTIR spectra by attenuated total reflectancetechnique and scanning electron microscopy (SEM) pictures of the polymers were taken both before and after adsorption experiments. Total metal ion removal capacities of PAMPS and P(AMPS‐co‐IA) were 1.685 and 1.722 mmol Me²⁺/g_polymer, respectively. Experimental data were evaluated to determine the kinetic characteristics of the adsorption process. Competitive adsorption of Pb²⁺, Cu²⁺, and Cd²⁺ ions onto both PAMPS and P(AMPS‐co‐IA) was found to fit pseudo‐second‐order type kinetics. In addition, the removal orders in the competitive adsorption of these metal ions onto PAMPS and P(AMPS‐co‐IA) were found to be Cd²⁺ > Pb²⁺ > Cu²⁺ and Pb²⁺ > Cd²⁺ > Cu²⁺, respectively. Copyright © 2008 John Wiley & Sons, Ltd.     

Complexation of iminodisuccinic acid (IDS) and 3-hydroxy-2,2′-iminodisuccinic acid (HIDS) with Cd2+, Hg2+, and Pb2+ in aqueous solution

In a search for environmentally friendly metal-chelating ligands for industrial applications, the protonation and complex formation equilibria of iminodisuccinic acid (IDS) and 3-hydroxy-2,2′-iminodisuccinic acid (HIDS) with Cd²⁺, Hg²⁺, and Pb²⁺ in aqueous 0.1?mol?L^?1 NaNO₃ solution were studied at 25°C by potentiometric titration. Models for complexation and stability constants of the different complexes were determined for each metal ion using the computer program SUPERQUAD. In all cases, complex formation was dominated by stable ML^2? complexes.     

Metal ion complexation in acetonitrile by di-ionized calix[4]arenes bearing two dansyl fluorophores

The influence of metal cations (Li⁺, Na⁺, K⁺, Rb⁺, Cs⁺, Mg²⁺, Ca²⁺, Sr²⁺, Ba²⁺, Ag⁺, Cd²⁺, Co²⁺, Fe²⁺, Hg²⁺, Mn²⁺, Pb²⁺, Zn²⁺ and Fe³⁺) on the spectroscopic properties of two dansyl (1-dimethylaminonaphthalene-5-sulfonyl) groups linked to the lower rims of a series of three, structurally related, di-ionized calix[4]arenes was investigated by means of absorption and emission spectrophotometry. Di(tetramethylammonium) salts of the di-ionized ligands, (TMA)₂L1, (TMA)₂L2 and (TMA)₂L3, which differ in having zero, two and four tert-butyl groups, respectively, on the upper rim of the calix[4]arene scaffold were utilized for the spectrofluorimetric titration experiments in acetonitrile. On complexation by alkaline earth metal cations, both the absorption and emission spectra undergo marked red shifts and quenching of the dansyl fluorescence. These effects are weaker with alkali metal cations. Transition metal cations interact strongly with the ligands. In particular, Fe³⁺, Hg²⁺ and Pb²⁺ cause greater than 97% quenching of the dansyl fluorescence in the di-ionized ligands.     

A three‐dimensional CdII coordination polymer constructed from 1,1′‐biphenyl‐2,2′,5,5′‐tetracarboxylate and 1,4‐bis(1H‐imidazol‐1‐yl)benzene ligands

The title coordination polymer, poly[[aqua(μ₅‐1,1′‐biphenyl‐2,2′,5,5′‐tetracarboxylato)bis[μ₂‐1,4‐bis(1H‐imidazol‐1‐yl)benzene]dicadmium(II)] dihydrate], {[Cd₂(C₁₆H₆O₈)(C₁₂H₁₀N₄)₂(H₂O)]·2H₂O}_n, was crystallized from a mixture of 1,1′‐biphenyl‐2,2′,5,5′‐tetracarboxylic acid (H₄bpta), 1,4‐bis(1H‐imidazol‐1‐yl)benzene (1,4‐bib) and cadmium nitrate in water–dimethylformamide. The crystal structure consists of two crystallographically independent Cd^II cations, with one of the Cd^II cations possessing a slightly distorted pentagonal bipyramidal geometry. The second Cd^II centre is coordinated by carboxylate O atoms and imidazole N atoms from two separate 1,4‐bib ligands, displaying a distorted octahedral CdN₂O₄ geometry. The completely deprotonated bpta⁴⁻ ligand, exhibiting a new coordination mode, bridges five Cd^II cations to form one‐dimensional chains viaμ₃‐η¹:η²:η¹:η² and μ₂‐η¹:η¹:η⁰:η⁰ modes, and these are further linked by 1,4‐bib ligands to form a three‐dimensional framework with a (4².6⁴)(4.6²)(4³.6⁵.7²) topology. The structure of the coordination polymer is reinforced by intermolecular hydrogen bonding between carboxylate O atoms, aqua ligands and crystallization water molecules. The solid‐state photoluminescence properties were investigated and the complex might be a candidate for a thermally stable and solvent‐resistant blue fluorescent material.