Isostructural Coordination Polymers Research Articles

Halogen-Bonds-Based Strategy for the Design of Highly Luminescent Lanthanide Coordination Polymers as Taggants for Plastic Waste Sorting.

Reactions in water between a lanthanide ion and 3,4,5,6-tetrachloro-phthalate lead to a new series of iso-structural coordination polymers with general chemical formula [Ln2(tcpa)3(H2O)6]∞ with Ln = Eu-Yb plus Y. The crystal structure has been solved on the Y-derivative. This compound crystallizes in the monoclinic system, space group P21/n (no. 14) with the following cell parameters: a = 6.2155(2) Å, b = 19.6652(7) Å, c = 30.3720(9) Å, β = 94.631(1)°, V = 3700.22(37) Å3, and Z = 4. Luminescence properties of homo- and heterolanthanide coordination polymers that belong to this structural family have been studied in detail. This study shows that, in this system, intermetallic energy transfers are very efficient and that dilution by an optically non active Gd3+ ion leads to quite efficient luminescent heterolanthanide coordination polymers. The luminescence of these compounds, dispersed at a low doping rate in a poly(methyl methacrylate) (PMMA) matrix, can be observed even with the naked eye. This study opens the way to the use of such compounds as taggants for optical sorting of plastic waste and consecutive recycling.

Construction and screening of spin-crossover-sponge materials based on iron(II)-triazole coordination polymers.

Iron(II)-triazole coordination polymers have attracted considerable interest for their synthetic versatility, which allows tuning their spin-crossover (SCO) properties. Embedding SCO solid particles in sponge matrices is a simple, powerful, and generic approach to construct processable SCO materials. Here, we have studied a series of magnetic frameworks based on partial ligand substitution by using different chemical mixtures of two organic ligands, yielding four isostructural coordination polymers. The integration of the hygroscopic SCO material has endowed the composite sponge with the ability to capture moisture under ambient conditions. In particular, not only does a spin-crossover transition during absorption occur, but also a color variation has been achieved by varying humidity. The consequences of cooperativity and the exposed surface of the composite sponge on the spin transition were evaluated and the most promising materials among them were screened. This work provides guiding significance for the fabrication and practical application of spin-crossover-sponge materials.

Ligand-Mediated Regulation of the Chemical/Thermal Stability and Catalytic Performance of Isostructural Cobalt(II) Coordination Polymers.

Regulating the chemical/thermal stability and catalytic activity of coordination polymers (CPs) to achieve high catalytic performance is topical and challenging. The CPs are competent in promoting oxidative cross-coupling, yet they have not received substantial attention. Here, the ligand effect of the secondary ligand of CPs for oxidative cross-coupling reactions was investigated. Specifically, four new isostructural CPs [Co(Fbtx)1.5(4-R-1,2-BDC)]n (denoted as Co-CP-R, Fbtx = 1,4-bis(1,2,4-triazole-1-ylmethyl)-2,3,5,6-tetrafluorobenzene, 4-R-1,2-BDC = 4-R-1,2-benzenedicarboxylate, R = F, Cl, Br, CF3) were prepared. It was found that in the reactions of oxidative amination of benzoxazoles with secondary amines and the oxidative coupling of styrenes with benzaldehydes, both the chemical and thermal stabilities of the four Co-CPs with the R group followed the trend of -CF3 > -Br > -Cl > -F. Density functional theory (DFT) calculations suggested that the difference in reactivity may be ascribed to the effect of substituent groups on the electron transition energy of the cobalt(II) center of these Co-CPs. These findings highlight the secondary ligand effect in regulating the stability and catalytic performance of coordination networks.

Isomorphous and Isostructural Coordination Polymers Besides Metal‐Organic Frameworks (MOFs) of bis(4‐Nitrophenyl)‐phosphoric Acid in Conjunction with Some N‐donor Compounds

AbstractVarious coordination complexes, in the form of infinite coordination polymers and metal‐organic frameworks (MOFs) of an organophosphorous acid, bis(4‐nitrophenyl)phosphoric acid (BNPP), in the presence of some N‐donor compounds like 4,4′‐bipyridine (bpy), 1,2‐bis(4‐pyridyl)ethene (bpyee), 1,2‐bis(4‐pyridyl)ethane (bpyea) and 1,3‐bis(4‐pyridyl)propane (bpypa) along with metal ions, Co+2, Cd+2, Cu+2, and Ni+2, have been reported. Using the single crystal X‐ray diffraction method, the obtained structures are classified into isomorphous, isostructural coordination polymers, and metal‐organic framework structures. Except for the structures, formed by bpy with Ni(II) and Cu(II), bpypa with Cu(II) and bpyee with Co(II) and Ni(II), all of the complexes crystallize with both BNPP and N‐donor ligands forming coordinate bonds with the metal ions, yielding dumbbell‐shaped moieties in the lattices. A noteworthy feature in the structures obtained with bpyee, is that BNPP molecules do not form coordination bonds with metal ions Co(II) and Ni(II), while N‐donor ligands (bpyee) are only connected to the metal ions. Furthermore, in these complexes, the BNPP molecules occupy the same positions in the crystal lattice as those of coordinated BNPP moieties, but by hydrogen bonds, thus, establishing a high correlation of isostructurality in three‐dimensional packing between structures having coordinated and uncoordinated BNPP molecules, and highlighting the significance of hydrogen bonds in comparison with coordinated bonds. All of the complexes described, herein, are stabilized by different types of intermolecular interactions, specifically through a large number of C−H⋅⋅⋅O hydrogen bonds. Hirshfeld analysis further demonstrates surface properties and establishes accountability of various intermolecular interactions towards the stabilization of the complexes, emphasising, in particular, the importance of the C−H⋅⋅⋅O hydrogen bonds

Unprecedented Coordination Compounds with 4,4′-Diaminodiphenylethane as a Supramolecular Agent and Ditopic Ligand: Synthesis, Crystal Structures and Hirshfeld Surface Analysis

In this pioneering research, mononuclear coordination complexes and coordination polymers were obtained using the conformationally flexible ditopic ligand 4,4′-diaminodiphenylethane and different metal salts (nitrates, sulfates, tetrafluoroborates and perchlorates). Seven new products, including the mononuclear complexes [Cd(2,2′-bpy)3](ClO4)2](dadpe)(4,4′-bpy) (1), [Ni(dadpe)2(H2O)4](SO4).H2O (2), one-dimensional coordination polymers {[Zn(NO3)(dadpe)(dmf)2](NO3)}n (3), {[Cd(2,2′-bpy)2(dadpe)](ClO4)2}n (4), and two-dimensional coordination polymers, {[Cd(4,4′-bpy)2(H2O)2](ClO4)2(dadpe)(EtOH)2}n (5), {[Co(4,4′-bpy)2(H2O)2](BF4)2(dadpe)(EtOH)2}n (6) and {[Cd(adi)(dadpe)](H2adi)}n (7), (dadpe=4,4′-diaminodiphenylethane, 2,2′-bpy=2,2′-bipyridine, 4,4′-bpy=4,4′-bipyridine, H2adi=adipic acid) were produced. The synthesized compounds were characterized by FTIR and single-crystal X-ray diffraction analyses. The dadpe was recorded as a neutral guest in the crystals of mononuclear complex 1 and in coordination polymers 5 and 6. In compound 2, two dadpe ligands coordinate in a monodentate mode and occupy two trans-positions in the [Ni(H2O)4(dadpe)2]2+ octahedral complex cation. Coordination polymers 3 and 4 represent single chains originating from dadpe as a bidentate linker in both. The H-donor’s possibilities of amino groups were utilized in the interconnection of coordination chains into H-bonded networks via NH(NH2)···O hydrogen bonds. The isostructural coordination polymers 5 and 6 comprise similar cationic square grids [M(4,4′-bpy)2(H2O)2]2+ [M=Cd (5), M=Co (6)], with sql topology balanced by the charge-compensated anions, while dadpe and EtOH as neutral guests are situated in the interlayer space. The neutral 2D coordination network in 7 with the sql topology originates from both adi and dadpe linkers as bidentate-bridging ligands, and the neutral H2adi is entrapped as a guest in crystal lattice. The impact of different types of intermolecular interactions was evaluated by Hirshfeld surface analysis.

From isostructural to hetero-structural one-dimensional coordination polymers adjusted by changing the ligand substituent group from pyrazine to furan

A new ligand, 4-(4-carboxyphenyl)-6-(pyrazin-2-yl)picolinic acid (H2L1), was used to construct four isostructural one-dimensional (1 D) zig-zag chain coordination polymers ([M(L1)(H2O)2]·3H2O, M = Mn (1), Co (2), Cd (3) and Zn (4)). Moreover, when changing the ligand substituent group from pyrazine ring to furan ring, another new ligand, 4-(4-carboxyphenyl)-6-(furan-2-yl)picolinic acid (H2L2), was synthesized. Based on H2L2, different structural 1 D coordination polymers, ([Mn(L2)(H2O)2] (5) and [Ni(L2)(H2O)2]·H2O (6)), have been obtained under the same solvothermal conditions as for the syntheses of isostructural 1–4. Interestingly, only through changing the ligand substituent group, the 1 D isostructural zig-zag chain (1–4) was adjusted to a 1 D molecular box chain (5) and 1 D linear chain (6), which should be ascribed to ligand substituent group effects. The various 1 D chain structures originate from the types of ligand substituent group: the substituent group with a pyrazine ring only yields isostructural coordination polymers 1–4, whereas the substituent group with a furan ring can construct different structural coordination polymers, such as a 1 D molecular box chain (5) or a 1 D linear chain (6). The photoluminescent properties of all coordination polymers were also examined.

Differential supercapacitor and Schottky diode behaviours in two new isostructural coordination polymers based on redox active metal ions

Two isostructural 2D coordination polymers utilizing redox-active metal ions, Fe(ii) and Mn(ii), were synthesized. The Mn-based compound showed higher capacitance values and ten times higher conductivity compared to the Fe-based compound.

Lanthanide(III) Ions and 5-Methylisophthalate Ligand Based Coordination Polymers: An Insight into Their Photoluminescence Emission and Chemosensing for Nitroaromatic Molecules.

The work presented herein reports on the synthesis, structural and physico-chemical characterization, luminescence properties and luminescent sensing activity of a family of isostructural coordination polymers (CPs) with the general formula [Ln2(μ4-5Meip)3(DMF)]n (where Ln(III) = Sm (1Sm), Eu (2Eu), Gd (3Gd), Tb (4Tb) and Yb (5Yb) and 5Meip = 5-methylisophthalate, DMF = N,N-dimethylmethanamide). Crystal structures consist of 3D frameworks tailored by the linkage between infinite lanthanide(III)-carboxylate rods by means of the tetradentate 5Meip ligands. Photoluminescence measurements in solid state at variable temperatures reveal the best-in-class properties based on the capacity of the 5Meip ligand to provide efficient energy transfers to the lanthanide(III) ions, which brings intense emissions in both the visible and near-infrared (NIR) regions. On the one hand, compound 5Yb displays characteristic lanthanide-centered bands in the NIR with sizeable intensity even at room temperature. Among the compounds emitting in the visible region, 4Tb presents a high QY of 63%, which may be explained according to computational calculations. At last, taking advantage of the good performance as well as high chemical and optical stability of 4Tb in water and methanol, its sensing capacity to detect 2,4,6-trinitrophenol (TNP) among other nitroaromatic-like explosives has been explored, obtaining high detection capacity (with Ksv around 105 M-1), low limit of detection (in the 10-6-10-7 M) and selectivity among other molecules (especially in methanol).

Photocatalytic properties of two new isostructural cobalt(II) and nickel(II) complexes having terphenyl-3,3″,4,4″-teteacarboxylic acid

The effective and rapid removal of organic pollutants from wastewater is very important for the safety of aquatic environment. Photocatalytic degradation is a feasible strategy that can safely eliminate the organic pollutants from the wastewater discharge. Amongst varied class of photocatalysts, the coordination polymers (CPs) are important class of material that can be used to remove and degrade the organic dyes from wastewater. Herein, two isostructural coordination polymers, having compositions [Ni2(H2L)2(phen)4·H4L·6H2O)] (1) and [Co2(H2L)2(bipy)4·H4L·6H2O)] (2) (H4L = terphenyl-3,3″,4,4″-teteacarboxylic acid, phen = 1,10-phenanthroline and bipy = 2,2′-bipyridine) have been synthesized and characterized. Both of the isostructural compounds display dinculear architecture, where metal centers are coordinated to two carboxylic groups, which further forms a 2D supramolecular layer via hydrogen bonds formed between the water molecules and uncoordinated carboxylate groups. Both the compounds have been used as photocatalysts to catalyze the photodegradation of methylene blue (MB) and methylene violet (MV) under UV irradiation. The Ni(II)-based photocatalyst 1 exhibited the good photocatalytic performance in comparison to that of 2. The observed differences in the photocatalytic properties of both the CPs have been addressed using Hirshfeld surface analyses.

Investigation of Intermetallic Energy Transfers in Lanthanide Coordination Polymers Molecular Alloys: Case Study of Trimesate-Based Compounds.

Reactions in water at ambient temperature and pressure between a lanthanide ion and benzene-1,3,5-tricarboxylate (or trimesate) lead to two series of iso-structural coordination polymers. Their general chemical formula is [Ln(tma)(H2O)6]∞ for the lightest lanthanide ions (Ln = La-Dy except Pm), while it is [Ln(tma)(H2O)5·3.5H2O]∞ for the heaviest ones (Ho-Lu plus Y). For the heaviest lanthanide ions, reactions at 50 °C lead to a third structural family with the general chemical formula [Ln(tma)(H2O)3·1.5H2O]∞ with Ln = Ho-Lu plus Y. Homo-lanthanide coordination polymers that belong to the latter two families do not exhibit luminescence in the visible region. Therefore, we used a phase induction strategy to obtain molecular alloys that belong to these structural families and show sizeable emission. The random distribution of the lanthanide ions over the metallic sites has been investigated using 89Y and 139La solid-state NMR spectroscopy experiments. Luminescent properties of homo- and hetero-nuclear coordination polymers based on Eu3+ and Tb3+ have been studied in detail and compared. As a result, this study strongly suggests that exchange-based intermetallic energy transfer mechanisms play an important role in these systems. It also suggests the presence of an intermetallic exchange pathway through π-stacking interactions.

Bimetallic phosphide nanoparticles embedded in carbon nanostrips for electrocatalytic water oxidation

The development of low-cost and stable catalysts to enhance the electrocatalytic performance of oxygen evolution reaction (OER) has long been a concern. Herein, the rational synthesis of bimetallic phosphide nanoparticles anchored onto N-doped carbon of CoNiP/NC-X (X = 1, 2, 3 represent the molar ratio between Co and Ni of 1:1, 1:2, 2:1 in crystalline precursors, respectively) nanocomposites as high-performance electrocatalysts, which are calcined from a series of Co/Ni-based isostructural coordination polymers as the precursors. After pyrolysis, the as-obtained CoNiP/NC-1 nanostrips are intrinsically endowed with favorable nanostructure, large specific surface area, suitable heteroatom doping, abundant catalytic active sites and highly graphitic carbon network. Therefore, it exhibits a decent quasi-4-electron OER performance with a small overpotential of 330 mV at 10 mA cm−2, a low Tafel slope of 80.5 mV dec−1 and a 94.27% current retention after 10 hours in alkaline solution. The hierarchical nanostructures of CoNiP/NC-X series and their positive response to electrocatalytic properties have shed light on the preparation of other non-noble metal based carbon nanomaterials for efficient energy-related applications.

Syntheses, structures and magnetic properties of two CoII/NiII isostructural coordination polymers based on an asymmetric semirigid tricarboxylate ligand.

Two new isostructural complexes, namely, poly[aqua[μ3-2-(4-carboxyphenoxy)terephthalato-κ3O1:O4:O4'](1,10-phenanthroline-κ2N,N')cobalt(II)], [Co(C15H8O7)(C12H8N2)(H2O)]n or [Co(μ3-Hcpota)(phen)(H2O)]n, I, and poly[aqua[μ3-2-(4-carboxyphenoxy)terephthalato-κ3O1:O4:O4'](1,10-phenanthroline-κ2N,N')nickel(II)], [Ni(C15H8O7)(C12H8N2)(H2O)]n or [Ni(μ3-Hcpota)(phen)(H2O)]n, II, have been synthesized by solvothermal reactions. Complexes I and II were fully characterized by IR spectroscopy, elemental analyses, thermogravimetric analyses, and powder and single-crystal X-ray diffraction. They both present two-dimensional structures based on [M2(μ-COO)2]2+ (M= CoII or NiII) dinuclear metal units with a fes topology and a vertex symbol (4·82). Interestingly, the positions of the two dimeric metal motifs and the two partially deprotonated Hcpota2- ligands reproduce regular flying butterfly arrangements flipped upside down and sharing wings in the ab plane. Magnetic studies indicate antiferromagnetic interactions (J= -5.21 cm-1 for I and -11.53 cm-1 for II) in the dimeric units, with Co...Co and Ni...Ni distances of 4.397 (1) and 4.358 (1) Å, respectively, that are related to double syn-anti carboxylate bridges.

Structural and Electrochemical Studies of Cobalt(II) and Nickel(II) Coordination Polymers with 6-Oxonicotinate and 4,4′-Bipyridine

The 6-oxonicotinate (6-Onic) salts of a one-dimensional cationic cobalt(II) or nickel(II) coordination polymers with 4,4′-bipyridine (4,4′-bpy), namely {[Co(4,4′-bpy)(H2O)4](6-Onic)2·2H2O}n (1) and {[Ni(4,4′-bpy)(H2O)4](6-Onic)2·2H2O}n (2), were prepared hydrothermally by reactions of cobalt(II) nitrate hexahydrate or nickel(II) nitrate hexahydrate, respectively, 6-hydroxynicotinic acid and 4,4′-bipyridine in a mixture of ethanol and water. In the hydrogen-bonded frameworks of 1 and 2, the one-dimensional polymeric chains of {[M(4,4′-bpy)(H2O)4]2+}n (M = Co, Ni), the 6-oxonicotinate anions and the lattice water molecules were assembled via strong intermolecular O–H···O and N–H···O hydrogen bonds and π–π interactions, leading to the formation of the representative hydrogen-bond ring motifs: trimeric R23(10) motif, the centrosymmetric tetrameric R24(8) and R24(12) motifs and the pentameric R45(12) motif. The isostructural coordination polymers 1 and 2 exhibited a different electrochemical behavior, as observed by cyclic voltammetry, which can be attributed to the nature of the metal ions (cobalt(II) vs. nickel(II)).

A series of three dimensional lanthanoid(III)-metal-organic frameworks with zwitterionic linker

A series of isostructural 3D lanthanoid coordination polymers, {[Ln(µ4-cbpy)2]Br·xsolvent}n (Ln = La(1), Pr(2), Nd(3), Sm(4), Gd(5), Tb(6), Dy(7) and Ho(8), (H2cbpy)Br = 4-carboxy-1-(4-carboxybenzyl)pyridinium bromide), have been solvothermally synthesized and characterized by single-crystal X-ray diffraction, IR and elemental analysis. Powder X-ray diffraction (PXRD) and thermal analyses (TG, DTA and DTA) of 1–8 were also investigated. The single crystal X-ray diffraction analyses revealed that 1–8 were isostructural and crystallized in the monoclinic space group C2/c. In the complexes, each cbpy– acts as a tetrakis(monodentate) to connect to four Ln(III) ions. A pair of Ln(III) ions are coordinated by four carboxylate oxygen atoms to form paddle-wheel {Ln2(RCOO)4} secondary building units which are connected by four cbpy– ligand to form a 3D structure with scu topology.

Two 2D Co(II)/Mn(II) coordination polymers based on the quinoline-2,3-dicarboxylate ligand: synthesis, crystal structure, and fluorescence properties

Abstract A pair of two-dimensional (2D) isostructural coordination polymers (CPs), {[Co(2,3-qldc)(H2O)]} n (1) and {[Mn(2,3-qldc)(H2O)]} n (2), where 2,3-H2qldc = quinoline-2,3-dicarboxylic acid, were hydrothermally synthesized and characterized through IR spectroscopy, elemental and thermal analysis, power X-ray diffraction, and single-crystal X-ray diffraction. The results have revealed that the fully deprotonated 2,3-H2qldc ligand connects the Co(II)/Mn(II) atoms with a μ 3-bridge to form a square-wave 2D network, which is further extended into 3D stacks through O–H···O, C–H···O hydrogen bonds and π···π stacking interactions. Topologically, 1 or 2 can be simplified as a 4-connected sql type with a Schläfli symbol {44·62} and a Shubnikov tetragonal plane net, or as a 3-connected fes type with a Schläfli symbol {4·82} and a Shubnikov plane net. The thermal stability and the solid state fluorescence properties of 1 and 2 were investigated.

Four new isostructural metal-organic frameworks constructed by a new butterfly-typed nitroheterocyclic carboxylic acid: Synthesis, crystal structures and properties

Four new isostructural coordination polymers, [M2(μ2-H2O)(DTBC)2] (CTGU- 26(M), M ​= ​Zn, Cd, Co and Ni] have been prepared with a new butterfly-typed nitroheterocyclic 4,6-di- 1H-1,2,4-triazol-1-yi-1,3-benzenedicarboxylic acid(H2DTBC) ligand and metal salts under hydrothermal condition. CTGU-26(Zn) features an unusual 2-nodal (4, 8)-connected scu topological network generated by [Zn2(μ2-H2O)(COO)4] units and DTBC2− anion linkers. Luminescent properties measurements indicate that both CTGU-26(Zn) and CTGU-26(Cd) show intense fluorescence-emission compared with free H2DTBC ligand in solid state. Moreover, the electrocatalytic activities of CTGU-26(Co) and CTGU-26(Ni) towards methanol oxidation reaction (MOR) of two compounds were also investigated. Remarkably, by combining each MOF with the conductive 2,3,6,7,10,11-hexahydroxytriphenylene(HHTP) additive, a composite material, HHTP/CTGU-26(Ni)–I was confirmed to have an excellent performance for MOR with a high mass specific peak current of 25.55 ​mA ​cm−2.

Efficient Restraint of Intra‐Cluster Aggregation‐Caused Quenching Effect Lighting Room‐Temperature Photoluminescence

AbstractAt room temperature (RT), the weak and strong cluster‐centered luminescence of silver and copper iodide clusters, respectively, has been widely reported. Though the central metal ions show same d10 electrons and similar coordination mode, the mechanism of their distinct emission properties is still unclear, which restricts further applications. In this work, it is found that different photoluminescence quantum yields (PLQYs) are caused by various collision energy transfers between the metal ions in clusters, like a kind of aggregation‐caused quenching mechanism. Concretely, isostructural coordination polymers (CPs) of Ag(I) and Cu(I) iodide clusters are synthesized. The Ag(I)‐CP shows no luminescence at RT while the PLQY of Cu(I)‐CP boosts to 89%, in which short radius and weak collision between metal ions are found. Moreover, shorter Cu(I)‐Cu(I) and longer Ag(I)‐Ag(I) distances are realized in the similar structure and they display prospective luminescence, which proves the collisional quenching mechanism. Inspired of the above, the heterometallic materials with high sensitivities and wide sensing windows to temperature detection are obtained through tuning the metal content, and they are also fabricated into detecting sequences, which satisfies the wide‐range temperature sensing. This work proposes an efficient strategy to improve RT photoluminescence and broaden temperature sensing windows.

Facile solvothermal syntheses of isostructural lanthanide(III) formates: Photocatalytic, photoluminescent chemosensing properties, and proficient precursors for metal oxide nanoparticles

Three isostructural lanthanide coordination polymers (CPs) with the formula C3H3LnO6 [Ln = Pr (1), Ce (2), and Dy (3)] were solvothermally synthesized by self-assembly of lanthanide(III) and in-situ generated methanoic acid by the hydrolysis of N,N-dimethyl formamide. These CPs were characterized by FTIR, elemental analysis, PXRD, and single crystal analysis. The metal centered luminescence properties of these coordination polymers revealed that only the dysprosium based CP exhibited significant luminescence, and it was found to be selective for chemosensing of picric acid. 3 showed quenching efficiency of 89.7% with KSV value of 2.89 × 104 M−1. These coordination polymers were also exploited as photocatalysts for degradation of methylene blue, and the dysprosium based CP proved to be a fantastic photocatalyst with the degradation activity of 92% owing to its effective electronic transitions. The solvent-free thermolysis of these LnCPs fabricated CeO2 and Pr6O11 nanoparticles characterized by PXRD, FTIR, particle size analyzer, and elemental analysis.

Bromine heavy-atom induced persistent room temperature phosphorescence of [ZnBr2] based coordination polymer

Molecule-based room temperature phosphorescence (RTP) materials have attracted considerable attention owing to their extensive applications in the optoelectronic and biological field. In this paper, two isostructural coordination polymers [Zn3(TIB)2X6] (X ​= ​Cl, 1-Cl; X ​= ​Br, 1-Br) have been synthesised and characterized by the assemble of triangular D-A-D ligand 1,3,5-tri(1H-imidazol-1-yl)benzene (TIB) and ZnX2 salts. The incorporation of halogen atoms play significant role in the formation of abundant C-H···X hydrogen-bonding interactions and dense structures, enable high thermal stability of the two complexes. 1-Br shows phosphorescence lifetime three order of magnitude longer than that of 1-Cl, and obviously phosphorescence emission recognized by naked eyes. The theory calculations reveal complete separation of molecular orbitals between halogen atoms and TIB ligand. Photoelectron response performance have also been studied. This work provides an efficient way to achieve long-last RTP by the incorporation of metal-bromide units in the coordination polymers.

Luminescent 1D heterometallic (Ir,Cd) coordination polymers based on bis-cyclometalated Ir(III) metallatectons and trinuclear Cd(II) dianionic nodes.

Seven isostructural heterometallic luminescent (Ir,Cd) coordination polymers were prepared upon the combination of tris-chelate cationic Ir(III) complexes behaving as metalloligands with Cd(II) salts. Three octahedral Ir(III) complexes have been considered in the present report. They consist of a bipyridine unit functionalised with 3-pyridyl moieties as peripheral coordinating sites and two 2-phenylpyridyl cyclometalating derivatives. Three cadmium halide salts CdX2 (X = Cl, Br, I) were used and rearranged themselves during the self-assembly process with the metallatectons to afford a dianonic trinuclear Cd node [Cd3X8]2-. Seven out of the nine possible metallotecton-metal salt combinations could be characterised in the crystalline phase by X-ray diffraction on single crystals proving the isostructurality of the seven extended architectures studied. All of the CPs are luminescent with small shifts observed in the emission wavelength compared to the discrete complexes. Depending on the degree of fluorination of the two cyclometalating units, tuning of the emission wavelength of the discrete complexes as well as of the resulting coordination polymers is achieved.