CdII Centers Research Articles

A New Cd(II)-Based Coordination Polymer for Efficient Photocatalytic Removal of Organic Dyes.

Coordination polymers (CPs) are a diverse class of multi-dimensional compounds that show promise as photocatalysts for degrading dyes in polluted water. Herein, a new 1D Cd(II)-based coordination polymer with the formula [Cd(bpyp)(nba)2] (1) (bpyp = 2,5-bis(pyrid-4-yl)pyridine and Hnba = 4-nitrobenzoic acid) is synthesized and characterized. In 1, the two carboxyl groups of two different nba- ligands show μ2-η1:η1 and μ1-η1:η1 coordination modes to connect the CdII centers and sit on either side of the chain along the b direction. The produced CP 1 was utilized as the photocatalyst in the process of the photodegradation of methyl blue (MB), methyl orange (MO), rhodamine B (RhB), and methyl violet (MV) dyes when exposed to UV light. The photocatalytic degradation activities of CP 1 were analyzed, and the results suggest that it exhibits an extraordinary efficiency in the degradation of MB, MV, MO, and RhB. RhB has a 95.52% efficiency of degradation, whereas MV has a 58.92% efficiency, MO has 35.44%, and MB has 29.24%. The photodecomposition of dyes is catalyzed mostly by •O2- and •OH-, as shown by research involving the trapping of radicals.

Visible Light and Microwave‐Mediated Rapid Trapping and Release of Singlet Oxygen Using a Coordination Polymer

AbstractDue to its high reactivity and oxidative strength, singlet oxygen (1O2) is used in a variety of fields including organic synthesis, biomedicine, photodynamic therapy and materials science. Despite its importance, the controlled trapping and release of 1O2 is extremely challenging. Herein, we describe a one‐dimensional coordination polymer, CP1, which upon irradiation with visible light, transforms 3O2 (triplet oxygen) to 1O2. CP1 consists of CdII centers bridged by 9,10‐bis((E)‐2‐(pyridin‐4‐yl)vinyl)anthracene ligands which undergo a [4+2] cycloaddition reaction with 1O2, resulting in the generation of CP1−1O2. Using microwave irradiation, CP1−1O2 displays efficient release of 1O2, over a period of 30 s. In addition, CP1 exhibits enhanced fluorescence and has an oxygen detection limit of 97.4 ppm. Theoretical calculations reveal that the fluorescence behaviour is dominated by unique through‐space conjugation. In addition to describing a highly efficient approach for the trapping and controlled release of 1O2, using coordination polymers, this work also provides encouragement for the development of efficient fluorescent oxygen sensors.

Solvent influence on the crystal structures of new cadmium tri-tert-butoxysilanethiolate complexes with 1,4-bis(3-aminopropyl)piperazine: luminescence and antifungal activity.

Monocrystals of dinuclear μ-1,4-bis(3-aminopropyl)piperazine-κ4N1,N1':N4,N4'-bis[bis(tri-tert-butoxysilanethiolato-κS)cadmium(II)], [Cd2(C12H27O3SSi)4(C10H24N4)] or [Cd2{SSi(OtBu)3}4(μ-BAPP)], 1, and polynuclear catena-poly[[bis(tri-tert-butoxysilanethiolato-κS)cadmium(II)]-μ-1,4-bis(3-aminopropyl)piperazine-κ2N1':N4'], [Cd(C12H27O3SSi)2(C10H24N4)]n or [Cd{SSi(OtBu)3}2(μ-BAPP)]n, 2, with 1,4-bis(3-aminopropyl)piperazine (BAPP) and tri-tert-butoxysilanethiolate ligands, were obtained from the same ratio of reactants, but with different solvents used for the crystallization processes. The structures and properties of both complexes were characterized using elemental analysis, X-ray diffraction and FT-IR, 1H NMR and luminescence spectroscopy. Applied density functional theory (DFT) computational methods and noncovalent interaction (NCI) analysis were used for geometry optimization and visualization of the interactions between the metallic centres and their surroundings. The X-ray analysis revealed four-coordinate CdII centres bound to two S atoms of the silanethiolate groups and two N atoms of the BAPP ligand; however, it chelates to tertiary and primary N atoms in 1, whilst in 2 it does not chelate and bonds only to RNH2. The photoluminescence properties of complexes 1 and 2 result from free-ligand emission and differ significantly from each other with respect to emission intensity. Additionally, antifungal activity was investigated against 18 isolates of fungi. Compound 1 strongly inhibited the growth of three dermatophytes: Epidermophyton floccosum, Microsporum canis and Trichophyton rubrum.

Fabrication and DFT Calculation of Amine-Functionalized Metal-Organic Framework as a Turn-On Fluorescence Sensor for Fe3+ and Al3+ Ions.

Due to their important role in biological systems, it is urgent to develop a material that can rapidly and sensitively detect the concentration of Fe3+ and Al3+ ions. In this work, a brand-new CdII-based metal-organic framework [Cd(BTBD)2(AIC)]n (JXUST-18, BTBD = 4,7-bis(1H-1,2,4-triazol-1-yl)-2,1,3-benzothiadiazole and H2AIC = 5-aminoisophthalic acid) with a 4-connected sql topology was designed and synthesized. The symmetrical CdII centers are linked by AIC2- ligands with μ3-η1:η1:η1:η1 coordination mode to form a [Cd2(COO)2] secondary building unit (SBU). The contiguous SBUs are further connected by BTBD ligands to form a two-dimensional (2D) layer structure. JXUST-18 can remain stable in aqueous solutions with pH values of 3-12 or in boiling water. Luminescent experiments suggest that JXUST-18 displays more than eightfold fluorescence enhancement in the presence of Fe3+ and Al3+ ions, and the detection limits for Fe3+ and Al3+ ions are 0.196 and 0.184 μM, respectively. Furthermore, the change in luminescence color is uncomplicatedly distinguishable with the naked eye under ultraviolet light at 365 nm. In addition, a series of devices based on JXUST-18 including fluorescence test strips, lamp beads, and composite films were developed to detect metal ions via visual changes in luminescence color. Significantly, JXUST-18 is a rare MOF-based turn-on fluorescence sensor for the detection of Fe3+ ions. The theoretical calculation suggests that the complexation of Fe3+/Al3+ ions and the -NH2 group contributes to fluorescence enhancement.

Construction and Photoluminescence Properties of a Three‐Dimensional CdII Coordination Polymer Based on 2,5‐Di(4‐carboxy‐phenylthio) Terephthalic acid, 1,2‐Di(pyridin‐4‐yl)diazene

AbstractIn recent years, metal‐organic frameworks composed of polydentate carboxylic acid esters and pyridyl ligands have attracted much attention because these ligands can adopt a variety of coordination modes to form crystalline products exhibiting interesting structures and various properties. A new cadmium(II) metal‐organic framework (MOF), poly[[half[μ5‐2,5‐di(4‐carboxy‐phenylthio) terephthalic acid‐κ5O1#3 : O2#3 : O3#2 : O4 : O4#2]][μ2‐1,2‐di(pyridin‐4‐yl)diazene‐κ2N1 : N4#1]cadmium(II)], namely [Cd(C22H10O8S2)0.5(C10H10N4)]n or [Cd(PSTP)0.5(4‐DiPyDz)]n, is constructed from CdII ions, 2,5‐di(4‐carboxy‐phenylthio) terephthalic acid (H4PSTP) and 1,2‐di(pyridin‐4‐yl)diazene (4‐DiPyDz) ligands under solvothermal conditions. The title compound was structurally characterized by single crystal X‐ray diffraction analysis, elemental analysis, powder X‐ray diffraction and IR spectroscopy. This structure indicates that in situ reduction of 4‐DiPyDz occurs during synthesis, containing a CdII center, a primary ligand H4PSTP and an ancillary ligand 4‐DiPyDz in one asymmetric unit. Thermal stability, solid state photoluminescence, and the ability to detect small organic molecules as fluorescent probes have also been investigated.

Synthesis, crystal structure and properties of a 2-D Cd(II) coordination polymer based on ferrocenecarboxylate and 4,4′-bipyridine ligands

Abstract A new cadmium(II)-based coordination polymer [Cd3(FcCOO)6(4,4′-bipy)(H2O)2] n (FcCOO = ferrocenecarboxylato and 4,4′-bipy = 4,4′-bipyridine) has been synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction. The results of a crystal structural analysis has revealed that the title compound consists of two crystallographically unique CdII centers, one in a general position with a five-coordinated and one on an inversion center with a six-coordinated environment. The CdII centers are connected by FcCOO− units to form a metal carboxylate oxygen chain extending parallel to the [100] direction while the 4,4′-bipy ligands further act as bridging linkers of the CdII centers resulting in a layered polymer. In addition, an X-ray powder diffraction and thermal gravimetric analysis and a cyclo-voltammetric characterization of the complex have also been carried out.

Tri- and pentanuclear CuII–CdII complexes of N2O2 donor ligands with the variation of carboxylate coligands: Structural elucidation and theoretical study

Three new heterometallic copper(II)-cadmium(II) complexes [(CuL1)2Cd3(C6H5CO2)6] (1), {[(CuL2)2Cd(o-(NO2)C6H4CO2)2]·2NCMe} (2), and [{CuL2(H2O)0.65(NCMe)0.35}2Cd3(m-(NO2)C6H4CO2)6] (3) have been synthesized using [CuL1]/[CuL2] as metalloligand (where H2L1 = N,N′-bis(2-hydroxynaphthyl-methylidene)-1,3-propanediamine, H2L2 = N,Ń-bis(methyl2-hydroxynaphthyl-methylidene)-1,3-propanediamine). Single crystal structure analyses reveal that complexes 1 and 3 exist as pentanuclear entities in which the [CuL1]/[CuL2] units are bonded to the terminal CdII centres of the benzoate (for 1)/m-nitro benzoate (for 3) bridged linear [Cd3(C6H5CO2)6] (for 1)/[Cd3(m-(NO2)C6H4CO2)6] (for 3) unit through double phenoxido oxygen atoms. On the other hand, complex 2 contains a linear, trinuclear structure in which the square pyramidal [CuL2] units are connected with the central octahedral CdII ion via double phenoxido bridges and also additionally through a syn-syn bridging o-nitro benzoate group. A theoretical investigation on the geometries and energies of the complexes reveals that in the presence of the naphthalene group in H2L1 the pentanuclear geometry of complex 1 is favored over the trinuclear ones, usually formed with the salen type ligands. In addition, substitution of benzoate ion at meta position by nitro group stabilizes pentanuclear structure more than ortho-substitution, corroborating the formation of pentanuclear complex 3 and trinuclear complex 2.

ZnII and CdII Metal Organic Frameworks Based on 2‐Methyl‐6‐oxygen‐1,6‐dihydro‐3,4'bipyridine‐5‐carbonitrile

To investigate the coordination chemistry of modbc (2‐methyl‐6‐oxygen‐1,6‐dihydro‐3,4'‐bipyridine‐5‐carbonitrile) with ZnII and CdII salts under the solvothermal conditions, six new MOFs with the formulas [Zn(modbc)2(mpa)]n (1), [Zn(modbc)(mpa)(H2O)]n (2), [Zn(modbc)(pa)0.5(H2O)]n (3), [Cd(modbc)(pa)0.5(H2O)]n (4), [Zn(modbc)2(tpa)]n (5), and [Cd(modbc)2(pda)(H2O)]n (6) (mpa = m‐phthalic acid; pa = pyromellitic acid; tpa = terephthalic acid; pda = pentane diacid) were successfully synthesized by solvothermal reaction and fully characterized by elemental analysis, IR spectroscopy, single crystal, powder X‐ray diffraction, thermal and photoluminescence properties. Though MOFs 3 and 4 have the same structure, we have obtained three different kinds of coordination configurations by the X‐ray diffration analysis. Compared with 1 and 2, coordination water has no effect on the solid fluorescence emission of MOFs. It is worth noting that the fluorescence intensity of 3 containing central ZnII atoms is very strong, whereas that of isomorphism 4 containing central CdII atoms has almost no fluorescence emission, showing that metal ions have very important influence on the fluorescence emission. Further, we found that solvents had an important effect on the fluorescence emission in liquid fluorescence of MOFs 1–6.

Two new CdII MOFs of 1,4-bis(1H-benzimidazol-1-yl)butane and flexible dicarboxylate ligands: luminescence sensing towards Fe3.

Two new CdII MOFs, namely, two-dimensional (2D) poly[[[μ2-1,4-bis(1H-benzimidazol-1-yl)butane](μ2-heptanedioato)cadmium(II)] tetrahydrate], {[Cd(C7H10O4)(C18H18N4)]·4H2O}n or {[Cd(Pim)(bbimb)]·4H2O}n (1), and 2D poly[diaqua[μ2-1,4-bis(1H-benzimidazol-1-yl)butane](μ4-decanedioato)(μ2-decanedioato)dicadmium(II)], [Cd2(C10H16O4)2(C18H18N4)(H2O)2]n or [Cd(Seb)(bbimb)0.5(H2O)]n (2), have been synthesized hydrothermally based on the 1,4-bis(1H-benzimidazol-1-yl)butane (bbimb) and pimelate (Pim2-, heptanedioate) or sebacate (Seb2-, decanedioate) ligands. Both MOFs were structurally characterized by single-crystal X-ray diffraction. In 1, the CdII centres are connected by bbimb and Pim2- ligands to generate a 2D sql layer structure with an octameric (H2O)8 water cluster. The 2D layers are further connected by O-H...O hydrogen bonds, resulting in a three-dimensional (3D) supramolecular structure. In 2, the CdII centres are coordinated by Seb2- ligands to form binuclear Cd2 units which are linked by bbimb and Seb2- ligands into a 2D hxl layer. The 2D layers are further connected by O-H...O hydrogen bonds, leading to an 8-connected 3D hex supramolecular network. IR and UV-Vis spectroscopy, thermogravimetric analysis and solid-state photoluminescence analysis were carried out on both MOFs. Luminescence sensing experiments reveal that both MOFs have good selective sensing towards Fe3+ in aqueous solution.

Hydrothermal syntheses of a series of copper (II), cadmium (II), and silver (I) coordination polymers with the new 3,5-bis-(triazol-1-yl)-pyridine ligand: structural diversity, anion pollutant absorption, and fluorescent properties

A series of novel copper (II), cadmium (II), and silver (I) coordination frameworks, {[CuL2(H2O)2]·2(ClO4)·2H2O}n (1), {[CdL2(H2O)2]·2(ClO4)·2H2O}n (2), and [AgL·CF3SO3]n (3) based on 3,5-bis-(triazol-1-yl)pyridine(L), have been isolated and characterized by single-crystal X-ray diffraction. In 1 and 2, the bi-dentate L bridges neighboring CuII centers and CdII centers generating the one-dimensional (1D) double-chain cationic coordination polymer, in which lattice-free ClO4 – and lattice water molecules are located between these neighboring 1D chains. In 3, these tri-dentate L bridge neighboring AgI centers, which construct the two-dimensional (2D) coordination framework. The terminal coordinated CF3SO3 – anions are decorated along the side of the 2D framework. Further, 1 also presents the novel example of cationic triazole-copper (II) coordination polymer for effectively capturing anion pollutants Cr2O7 2– in the water solutions. The solid-state luminescent properties of L and coordination polymers 2–3 were also investigated.

Solvo‐thermal Preparation and Characterization of Two CdII Coordination Polymers Constructed From 2,6‐(1,2,4‐Triazole‐4‐yl)pyridine and 5‐R‐Isophthalic Acid (R = Nitro, Sulfo)

Under the solvo‐thermal conditions, two novel CdII mixed‐ligand coordination materials with 2,6‐(1,2,4‐triazole‐4‐yl)pyridine(L1) and aromatic poly‐carboxylic acid co‐ligands such as 5‐R‐isophthalic acid (R = nitro, sulfo), namely [Cd(L1)(NO2‐BDC)(H2O)2]·2H2O (1) and [Cd(L1)(HSIP)(H2O)]·4H2O (2) (NO2‐H2BDC = 5‐nitroisophthalic acid, H3SIP = 5‐sulfobenzene ‐isophthalic acid) were successfully prepared. These CdII mixed‐ligand coordination polymers 1–2 have been measured by crystal X‐ray analysis, FT‐IR spectra and powder X‐ray diffraction analyses. In 1, these seven‐coordinate CdII atoms (Cd1) are inter‐linked by didentate 5‐nitroisophthalic acid ligands forming 1D chain structures. In 2, these L1 and partially de‐pronated HSIP2– are inter‐linked by central CdII centers and are arranged into the unique 2D micro‐porous metal‐organic framework of 2. Side view of 2, it is noted that numerous oxygen atoms of un‐coordinated carboxylate groups and coordinated SO3 groups protrude out and decorate the 2D framework of 2. PXRD patterns of 1 and 2 sample is tested, which is consistent with the simulated PXRD diffraction pattern. Photoluminescence studies show that 2 is highly selective and sensitive to trace elements of Eu3+ with excellent Ksv value (7.86 × 104 m–1) and low detection limit (5.56 × 10–2 mM), which also provides a convenient method and platform for real‐time detection of Eu3+.

A novel (3,6)-connected CdII coordination polymer based on an ether-linked tricarboxylate ligand: synthesis, topology and luminescence sensing properties in aqueous solution.

A novel three-dimensional coordination polymer, namely, poly[[diaquabis(μ-4,4'-bipyridine)bis{μ3-5-[(2-carboxyphenoxy)methyl]isophthalato}tricadmium(III)] dimethylformamide monosolvate 2.5-hydrate], {[Cd3(C16H9O7)2(C10H8N2)2(H2O)2]·2C3H7NO·5H2O}n, was obtained by the reaction of ether-linked 5-[(2-carboxyphenoxy)methyl]isophthalic acid (H3L) with CdII salts in the presence of 4,4'-bipyridine (bpy) under solvothermal conditions. In this complex, the CdII centres are connected by the carboxylate ligands to form two-dimensional wave-like layers, which are pillared by bpy ligands and extended into a rare three-dimensional (3,6)-connected sqc27 framework. The complex demonstrated good water stability and strong luminescence emissions. It not only possesses excellent luminescence sensing activities toward Fe3+ and Cr2O72- in aqueous solution, but can also distinguish between Cr2O72- and CrO42- by luminescence. Furthermore, it could be simply and quickly regenerated at least five times. A study of the sensing mechanism indicated that luminescence quenching may be related to the energy competition between the complex and sensing analytes.

Solvo‐thermal Preparation of One Novel Cadmium(II) Coordination Polymer with 1‐(4‐Aminobenzyl)‐1,2,4‐Triazole and Bi‐functional Photo‐Luminescent Sensing for Acetone and Dichromate

In this work a 1,2,4‐triazole derivative 1‐(4‐aminobenzyl)‐1,2,4‐triazole (abtz) was utilized, one new cadmium(II) coordination polymer, namely [Cd(abtz)I2]n (1) was prepared through the powerful solvo‐thermal synthetic strategy. In compound 1, the abtz building blocks are interlinked through the central CdII ions forming the two‐dimensional (2D) layer coordination framework. Powder X‐ray diffraction (PXRD) characterization also reveals that we have prepared the pure phases of coordination polymer 1. Optical properties have been determined, which can behave the excellent photo‐luminescent emission of coordination polymer 1. Photo‐luminescent experiment also reveals that coordination polymer 1 can behave the highly sensitive detection for acetone molecules with high Ksv value (Ksv = 4.12 ×104 L·mol–1) in the recyclable detection fashion. Additionally, coordination polymer 1 also can behave the highly sensitive detection for pollutant dichromate with excellent quenching efficiency Ksv (Ksv = 2.12 × 104 L·mol–1) and low detection limit [38 × 10–3 mM (S/N = 3)]. UV/Vis, photo‐luminescent lifetime, and PXRD patterns also have been determined to analyze the detection mechanism.

A Binuclear Cadmium(II) Cluster Based on π···π Stacking and Halogen···Halogen Interactions: Synthesis, Crystal Analysis and Fluorescent Properties

An interseting binuclear complex [Cd2(tcpa)4(bipy)2] (1) has been hydrothermally synthesized with 3, 5, 6-trichloropyridine phenoxy acetatic acid (Htcpa) and 2, 2′-bipyridine (bipy) coligands. The X-ray single-crystal diffraction analysis shows that the CdII center is situated on unusual triangular prismatic geometry formed by two pyridyl nitrogen atoms of a bipy molecule and four carboxyl oxygen atoms of four different tcpa− ligands. The four tcpa− anions play as bis-monodentate linkers and connect two CdII ions together to form the dimer structure of 1. 1 is further assembled into a 2D layer by the co-effects of π···π stacking and Cl···Cl halogen bonds interactions. Moreover, 1 exhibits intense solid-state luminescence emissions centered at 442 nm at room temperature, which mainly originates from the intraligand π → π* transitions of tcpa−. The CCDC number of 1 is 1,935,091.

Cadmium(II) three-dimensional coordination polymers constructed from 1,3,5-tris(4-carboxyphenoxy)benzene: synthesis, crystal structure, fluorescence and I2 sorption characterization.

Two three-dimensional (3D) CdII coordination polymers, namely poly[[di-μ-aqua-diaquabis{μ5-4,4',4''-[benzene-1,3,5-triyltris(oxy)]tribenzoato}tricadmium(II)] dihydrate], {[Cd3(C27H15O9)2(H2O)4]·2H2O}n, (I), and poly[[aqua{μ6-4,4',4''-[benzene-1,3,5-triyltris(oxy)]tribenzoato}(μ-formato)[μ-1,1'-(1,4-phenylene)bis(1H-imidazole)]dicadmium(II)] dihydrate], {[Cd2(C27H15O9)(C12H10N4)(HCOO)(H2O)]·2H2O}n, (II), have been hydrothermally synthesized from the reaction system containing Cd(NO3)2·4H2O and the flexible tripodal ligand 1,3,5-tris(4-carboxyphenoxy)benzene (H3tcpb) via tuning of the auxiliary ligand. Both complexes have been characterized by single-crystal X-ray diffraction analysis, elemental analysis, IR spectra, powder X-ray diffraction and thermogravimetric analysis. Complex (I) is a 3D framework constructed from trinuclear structural units and tcpb3- ligands in a μ5-coordination mode. The central CdII atom of the trinuclear unit is located on a crystallographic inversion centre and adopts an octahedral geometry. The metal atoms are bridged by four syn-syn carboxylate groups and two μ2-water molecules to form trinuclear [Cd3(COO)4(μ2-H2O)2] secondary building units (SBUs). These SBUs are incorporated into clusters by bridging carboxylate groups to produce pillars along the c axis. The one-dimensional inorganic pillars are connected by tcpb3- linkers in a μ5-coordination mode, thus forming a 3D network; its topology corresponds to the point symbol (42.62.82)(44.62)2(45.66.84)2. In contrast to (I), complex (II) is characterized by a 3D framework based on dinuclear cadmium SBUs, i.e. [Cd2(COO)3]. The two symmetry-independent CdII ions display different coordinated geometries, namely octahedral [CdN2O4] and monocapped octahedral [CdO7]. The dinuclear SBUs are incorporated into clusters by bridging formate groups to produce pillars along the c axis. These pillars are further bridged either by tcpb3- ligands into sheets or by 1,4-bis(imidazol-1-yl)benzene ligands into undulating layers, and finally these two-dimensional surfaces interweave, forming a 3D structure with the point symbol (4.62)(47.614). Compound (II) exhibits reversible I2 uptake of 56.8 mg g-1 with apparent changes in the visible colour and the UV-Vis and fluorescence spectra, and therefore may be regarded as a potential reagent for the capture and release of I2.

Synthesis, structure and photoluminescence properties of a three-dimensional cadmium(II) (4,5)-connected coordination network.

The assembly of coordination polymers from metal ions and organic moieties is currently attracting considerable attention in crystal engineering due to their intriguing architectures and potential applications as functional materials. A new coordination polymer, namely poly[[μ2-trans-1,2-bis(pyridin-3-yl)ethylene-κ2N:N']bis(μ4-4,4'-oxydibenzoato-κ6O:O,O':O'':O'',O''')dicadmium(II)], [Cd2(C14H8O5)2(C12H10N2)]n or [Cd2(4,4'-OBB)2(3,3'-BPE)]n, has been synthesized by the the self-assembly of Cd(NO3)2·4H2O, 4,4'-oxydibenzoic acid (4,4'-H2OBB) and trans-1,2-bis(pyridin-3-yl)ethene (3,3'-BPE) under hydrothermal conditions. The title compound was structurally characterized by IR spectroscopy, elemental analysis and single-crystal X-ray diffraction analysis. Each CdII centre is coordinated by six carboxylate O atoms from four different 4,4'-OBB2- ligands and by one pyridyl N atom form a 3,3'-BPE ligand. Adjacent crystallographically equivalent CdII ions are bridged by 4,4'-OBB2- ligands, affording a two-dimensional [Cd(4,4'-OBB)]n net extending in the ac plane. Neighbouring [Cd(4,4'-OBB)]n nets are interlinked by 3,3'-BPE along the b axis to form a three-dimensional (3D) [Cd2(4,4'-OBB)2(3,3'-BPE)]n coordination network. In the network, each CdII centre is linked by four different 4,4'-OBB2- ligands and one 3,3'-BPE ligand. Meanwhile, each 4,4'-OBB2- ligand connects four separate CdII ions. Therefore, if the 4,4'-OBB2- ligands and CdII ions are considered as 4- and 5-connecting nodes, the structure of the title compound can be simplified as a 3D (4,5)-connected binodal framework with the rare (4462)(4466) TCS topology (Pearson, 1985; Blake et al., 2011). The thermal stability and photoluminescence properties of the title compound have also been investigated.

A new magnetic hybrid based on a unique sulfur rich cadmium coordination polymer used for high selective photocatalytic degradation of cationic dyes

Abstract In the present work, a new kind of magnetic hybrid based on a unique sulfur rich cadmium coordination polymer (CdII-CP) has been prepared with a facile and efficient method via ultrasonic condition. The nano-structure of CdII-CP namely, [Cd (SCN)2L]n [where L = 1, 1-(1,4-butanediyl)bis(1,3-dihydro-3-methyl-1H-imidazole-2-thione] has been synthesized and fully characterized. The X-ray analysis shows the formation of an undulated polymeric two-dimensional network parallel to the (0 01) plane. The CdII centers adopt a trigonal bipyramidal geometry which is an uncommon core for a cadmium CP with CdS3N2 nodes. We have immobilized the CdII-CP with CoFe2O4 nanoparticles to build up CdII-CP @CoFe2O4 and CoFe2O4 @CdII-CP hybrids by sonochemical procedure. The photocatalytic efficiency was tested by monitoring the photocatalytic oxidation of cationic and anionic dyes under ultraviolet irradiation. In the dark condition, the CdII-CP shows a selective adsorption of anionic dye, while adsorption of the cationic dyes were negligible. Consequently, two independent studies have been performed. For the anionic dye adsorption/desorption behavior were examined, while for the cationic dyes, photo degradation phenomena was investigated. It is worth to note that the nanostructure of CdII-CP shows more photoresponse than the bulk CdII-CP .The direct excitation of nodes within the CdII-CP caused an electron transfer which is responsible for the photocatalytic degradation of dyes. A close inspection on the structure of CdII-CP revealed that the presence of nodes greatly improved the electron–hole separation and effectively convert the photo generated active ·OH radicals.

Synthesis and characterization of two one-dimensional CdII coordination polymers (CPs) with 5-amino-2,4,6-tribromoisophthalic acid and flexible N-donor bipyridyl ligands.

The bromo-substituted aromatic dicarboxylic acid 5-amino-2,4,6-tribromoisophthalic acid (H2ATBIP) was used to assemble with CdII ions in the presence of the N-donor flexible bipyridyl ligands 3,3'-(diazene-1,2-diyl)dipyridine (mzpy) and 1,3-bis(pyridin-3-ylmethyl)urea (3bpmu), leading to the formation of two chain coordination polymers by adopting solution methods, namely, catena-poly[[[triaqua(5-amino-2,4,6-tribromoisophthalato-κO)cadmium(II)]-μ-3,3'-(diazene-1,2-diyl)dipyridine-κ2N1:N1'] dihydrate], {[Cd(C8H2Br3NO4)(C10H8N4)(H2O)3]·2H2O}n or {[Cd(ATBIP)(mzpy)(H2O)3]·2H2O}n, (1), and catena-poly[[[tetraaquacadmium(II)]-μ-1,3-bis(pyridin-3-ylmethyl)urea-κ2N1:N1'-[diaquabis(5-amino-2,4,6-tribromoisophthalato-κO)cadmium(II)]-μ-1,3-bis(pyridin-3-ylmethyl)urea-κ2N1:N1'] octahydrate], {[Cd(C8H2Br3NO4)(C12H12N4O)(H2O)3]·4H2O}n or {[Cd(ATBIP)(3bpmu)(H2O)3]·4H2O}n, (2). Both complexes were characterized by FT-IR spectroscopic analysis, thermogravimetric analysis (TGA), solid-state diffuse reflectance UV-Vis spectroscopic analysis, and single-crystal and powder X-ray diffraction analysis (PXRD). The mzpy and 3bpmu ligands bridge the CdII metal centres in (1) and (2) into one-dimensional chains, and the ATBIP2- ligands show a monodentate coordination to the CdII centres in both coordination polymers. A discrete water tetramer exists in (1). Within the chains of (1) and (2), there are halogen bonds between adjacent ATBIP2- and mzpy or 3bpmu ligands, as well as hydrogen bonds between the ATBIP2- ligands and the coordinated water molecules. With the aid of weak interactions, the structures of (1) and (2) are further extended into three-dimensional supramolecular networks. An analysis of the solid-state diffuse reflectance UV-Vis spectra of (1) and (2) indicates that a wide indirect band gap exists in both complexes. Complexes (1) and (2) exhibit irreversible and reversible dehydration-rehydration behaviours, respectively, and the solid-state fluorescence properties of both complexes have been studied.

Construction of a three-dimensional supramolecular framework based on an anionic cadmium(II) coordination network and protonated dipyridine organic cations.

As a class of multifunctional materials, crystalline supramolecular complexes have attracted much attention because of their unique architectures, intriguing topologies and potential applications. In this article, a new supramolecular compound, namely catena-poly[4,4'-(buta-1,3-diene-1,4-diyl)dipyridin-1-ium [(μ4-benzene-1,2,4,5-tetracarboxylato-κ6O1,O1':O2:O4,O4':O5)cadmium(II)]], {(C14H14N2)[Cd(C10H2O8)]}n or {(1,4-H2bpbd)[Cd(1,2,4,5-btc)]}n, has been prepared by the self-assembly of Cd(NO3)2·4H2O, benzene-1,2,4,5-tetracarboxylic acid (1,2,4,5-H4btc) and 1,4-bis(pyridin-4-yl)buta-1,3-diene (1,4-bpbd) under hydrothermal conditions. The title compound has been structurally characterized by IR spectroscopy, elemental analysis, powder X-ray diffraction and single-crystal X-ray diffraction analysis. Each CdII centre is coordinated by six O atoms from four different (1,2,4,5-btc)4- tetraanions. Each CdII cation, located on a site of twofold symmetry, binds to four carboxylate groups belonging to four separate (1,2,4,5-btc)4- ligands. Each (1,2,4,5-btc)4- anion, situated on a position of -1 symmetry, binds to four crystallographically equivalent CdII centres. Neighbouring CdII cations interconnect bridging (1,2,4,5-btc)4- anions to form a three-dimensional {[Cd(1,2,4,5-btc)]2-}n anionic coordination network with infinite tubular channels. The channels are visible in both the [1-10] and the [001] direction. Such a coordination network can be simplified as a (4,4)-connected framework with the point symbol (4284)(4284). To balance the negative charge of the metal-carboxylate coordination network, the cavities of the network are occupied by protonated (1,4-H2bpbd)2+ cations that are located on sites of twofold symmetry. In the crystal, there are strong hydrogen-bonding interactions between the anionic coordination network and the (1,4-H2bpbd)2+ cations. Considering the hydrogen-bonding interactions, the structure can be further regarded as a three-dimensional (4,6)-connected supramolecular architecture with the point symbol (4264)(42687·84). The thermal stability and photoluminescence properties of the title compound have been investigated.

Structural variation and luminescence properties of d10 metal ions complexes from 5-Aminotetrazolate ligand

Three new d10 complexes with 5-aminotetrazolate (5-HATZ), [Zn2(5-ATZ)3(N3)]n (1), {[Cd6(5-ATZ)8Cl5]n·(H2O)4}n (2), and {[Cd12(5-ATZ)12Cl8(N3)4]·2H2O}n (3) have been obtained under hydrothermal conditions and structurally characterized. Single-crystal X-ray structural analyses reveal that complex 1 can be rationalized to be 3D dia topological nets with the metal ZnII centers acting as four-connected nodes and L acting as linkers, and the Schläfli symbol is 66, while 2 exhibits a 3D architecture based on six crystallographically independent hexahedral coordinated CdII centers linked by 5-ATZ anion and Cl anion. Complex 3 also possesses a 3D network linked by 5-ATZ anion, Cl anion as well as N3 anion. The ligand 5-ATZ anion adopts μ1,4-bridging coordination mode in complex 1, μ1,2,3, μ1,2,4, μ1,2,3,4-bridge coordination mode in complex 2, while μ1,2,4, μ1,2,3,4-bridge coordination mode in complex 3. Also, the fluorescent properties of complexes 1 and 2 have been investigated.