Polymeric Chain Structure Research Articles

Synthesis, crystal structure, magnetic studies, DNA binding, molecular docking studies, cytotoxicity and luminescence properties of a new coordination polymer copper(II) complex with 4,4′-trimethylenedipyridine and 1,10-phenanthroline

In the present work, a novel coordination polymer {[Cu(phen)(Tmdipy)(NO3)H2O](NO3) 2.5(H2O)}n (phen = 1,10-phenanthroline, Tmdipy = 4,4′- Trimethylenedipyridine), has been prepared and structurally determined by elemental analysis, IR, EPR, UV–visible and single-crystal X-ray crystallography. The complex crystallized in triclinic space group P -1, and the copper(II) shows a distorted octahedral geometry, with Jahn-Teller distortion occurring in the (4 + 2) CuN4O2 coordination sphere. The crystal structure evidences that the CP1 is formed of dinuclear [Cu(phen)(Tmdipy)(NO3)(H2O)]2 units weakly connected by nitrate anions giving rise to 1D polymeric chain structure. EPR measurement confirms about the distorted octahedral geometry of the complex. By using UV–Vis absorption, fluorescence spectroscopy, and cyclic voltammetric techniques, the binding studies of copper(II) complex with calf thymus DNA (CT-DNA) were investigated. Additionally, the gel electrophoresis method was used to examine the cleavage of pBR322 DNA by copper(II) complex and exhibited potent cytotoxic effects against human cell line (HepG2). Finally, magnetic properties, molecular docking studies and photoluminescence characteristics have been evaluated.

In vitro anticancer, antioxidant, antimicrobial, antileishmanial, enzymes inhibition and in vivo anti-inflammatory activities of organotin(IV) derivatives of 4-bromophenoxyacetic acid

Organotin(IV) derivatives {(n-C4H9)3SnL (1), (CH3)3SnL (2), (n-C4H9)2SnL2 (3) and (CH3)2SnL2 (4)} of 4-bromophenoxyacetic acid (HL) were synthesized and characterized by elemental, FT-IR, NMR and single crystal XRD diffraction analyses. The carboxylate ligand showed bridging/chelating bidentate coordination. The complexes 1 and 2 have adopted polymeric chain structures consisting tin atoms in distorted trigonal bipyramidal geometry. Complex 3 has shown highest DPPH radical scavenging (IC50 = 33.46 µg/mL) and antileishmanial activity (IC50 = 27.06 µg/mL). Complex 3 was also the most efficient agent in acetylcholinesterase (IC50 = 5.12 µg/mL), butyrylcholinesterase (IC50 = 13.79 µg/mL) and Monoamine oxidase (IC50 = 8.50 µg/mL) inhibition assays. Complex 4 (IC50 = 18.73 µg/mL) was the most potent ABTS radical scavenger. Complex 1 with IC50 values of 27.50 and 71.32 µg/mL was the most efficient α-glucosidase and dipeptidyl peptidase-4 enzyme inhibitor, respectively. While complex 2 was found the most potent Cyclooxygenase-2 (7.81 µg/mL) and 5-Lioxygenase (6.69 µg/mL) inhibitor. MTT assay revealed highest inhibitory potency of complexes 4 (IC50 = 8.035 ± 0.05 μg/ml), and 1 (IC50 = 10.16±0.17 μg/ml) towards the brain cancer cell line. The in vivo study performed on mice have shown potent anti-inflammatory effects of 1 and 2 comparable to the standard, indomethacin.

A homoleptic AgIII complex stabilized by succinimidate ligands.

Herein, the first example of a homoleptic AgIII complex stabilized by a monodentate N-donor ligand is presented. Na2[S2O8] oxidizes the linear AgI complex, Na[Ag(succ)2] (1Na), to form a square planar argentate(iii) ion, [Ag(succ)4]-, which crystallizes with a polymeric chain-structure, M[Ag(succ)4] (2M), when treated with alkali metal sulfate M2SO4 (M = K, Rb, Cs). A mixed-valent Robin-Day class I system, [(H2O)Ag][Ag(succ)4] (2Ag), forms in the absence of K+/Rb+/Cs+ ion. Diamagnetic 2Cs displays a succinimide C[double bond, length as m-dash]O stretching frequency at higher energy than does the isoelectronic PdII complex, [(H2O)Na]2[Pd(succ)4] (3Na). Moreover, 2Cs displays UV-vis absorptions that are more intense and occur at lower energy than those in 3Na. The electron-deficient nature of 2Cs is further evident from its ability to oxidize water to O2. From 109Ag magic-angle spinning NMR studies, a highly deshielded AgIII environment in 2Cs (2080 ppm) relative to the AgI starting material 1Na (492 ppm) is observed.

Novel triphenyltin(IV) compounds with carboxylato N-functionalized 2-quinolones as promising potential anticancer drug candidates: in vitro and in vivo evaluation.

Three newly synthesized triphenyltin(IV) compounds, Ph3SnL1 (L1- = 3-(4-methyl-2-oxoquinolin-1(2H)-yl)propanoato), Ph3SnL2 (L2- = 2-(4-methyl-2-oxoquinolin-1(2H)-yl)ethanoato), and Ph3SnL3 (L3- = 2-(4-hydroxy-2-oxoquinolin-1(2H)-yl)ethanoato), were characterized by elemental microanalysis, FT-IR spectroscopy and multinuclear (1H, 13C and 119Sn) NMR spectroscopy. A single X-ray diffraction study indicates that compounds Ph3SnL1 and Ph3SnL2 exhibit a 1D zig-zag chain polymeric structure, which in the case of Ph3SnL2 is additionally stabilized by π-interactions. In addition, the synthesized compounds were further examined using density functional theory and natural bond orbital analysis. The compounds have been evaluated for their in vitro anticancer activity against three human cell lines: MCF-7 (breast adenocarcinoma), A375 (melanoma), HCT116 (colorectal carcinoma), and three murine cell lines: 4T1 (breast carcinoma), B16 (melanoma), CT26 (colon carcinoma) using MTT and CV assays. The IC50 values fall in the nanomolar range, indicating that these compounds possess better anticancer activity than cisplatin. The study of the effect of the newly developed drug Ph3SnL1 showed its plasticity in achieving an antitumor effect in vitro, which depends on the specificity of the phenotype and the redox status of the malignant cell line and ranges from the initiation of apoptotic cell death to the induction of differentiation to a more mature cell form. In the syngeneic model of murine melanoma, Ph3SnL1 showed the potential to reduce the tumor volume similar to cisplatin, but in a well-tolerated form and with low systemic toxicity, representing a significant advantage over the conventional drug.

Enhanced selectivity towards melanoma cells with zinc(II)-Schiff bases containing imidazole derivatives.

Zinc(II)-complexes with the general formula [Zn(L)2] containing 8-hydroxyquinoline Schiff bases functionalized with 1-(3-aminopropyl)imidazole or 1-(3-aminopropyl)-2-methyl-1H-imidazole on 2-position and their respective ligands (HL1 or HL2) were synthesized and characterized by NMR, UV-Vis, FTIR and CD spectroscopies as well as ESI-MS spectrometry. Single crystals of HL2 and [Zn(L1)2]n were analysed by SC-XRD. [Zn(L1)2]n shows a 1D polymeric chain structure of alternating Zn(II) cations and bridging Schiff base ligands, in contrast to previously reported monomeric structures of analogous complexes. DFT calculations were performed to rationalize the polymeric X-ray structure of Zn(L1)2. Results showed that the ligands can bind as bi- or tridentate to Zn(II) and there is the possibility of a dynamic behavior for the complexes in solution. Both ligands and complexes present limited stability in aqueous media, however, in the presence of bovine serum albumin the complexes are stable. Molecular docking simulations and circular dichroism spectroscopic studies suggest binding to this protein in close proximity to the Trp213 residue. Biological studies on a panel of cancer cells revealed that the Zn(II)-complexes have a lower impact on cell viability than cisplatin, except for triple-negative breast cancer cells in which they were comparable. Notwithstanding, they display much higher selectivity towards cancer cells vs. normal cells, than cisplatin. They induce the generation of ROS and DNA double-strand breaks, primarily through apoptosis as the mode of cell death. Overall, the novel Zn(II)-complexes demonstrate improved induction of apoptosis and higher selectivity, particularly for melanoma cells, compared to previously reported analogues, making them promising candidates for clinical application.

Diverse Coordination Chemistry of the Whole Series Rare-Earth L-Lactates: Synthetic Features, Crystal Structure, and Application in Chemical Solution Deposition of Ln2O3 Thin Films.

Rare-earth (RE, Ln) carboxylates are widely studied as precursors of RE oxide-based nanomaterials; however, no systematic studies of RE L-lactates (HLact = 2-hydroxypropanoic acid) have been reported to date. In the present work, a profound structural investigation of RE L-lactates is carried out. A family of RE lactate complexes of the general formula LnLact3∙nH2O (Ln = La, Ce-Nd, Sm-Lu, Y; n = 2-3) are synthesized and characterized by CHN, TGA, and FTIR as well as by powder and single-crystal XRD methods.The existence of four novel structural types (1-Ln-4-Ln) is revealed. Compounds of the 1-Ln type (Ln = La, Ce, Pr) exhibit a chain polymeric structure, whereas 2-Ln-4-Ln compounds are molecular crystals consisting of dimeric (2-Ln; Ln = La, Ce-Nd) or monomeric (3-Ln-Ln = Sm-Lu, Y; 4-Ln-Ln = Sm-Gd, Y) species. The crystal structures of 1-Ln-4-Ln compounds are discussed in terms of their coordination geometry and supramolecular arrangement. Solutions of yttrium and lanthanum lactates with diethylenetriamine are applied for the chemical deposition of Y2O3 and La2O3 thin films.

Influence of polymeric molecular chain structure on the rheological-mechanical behavior of asphalt binders and porous asphalt mixes

This manuscript reports on two Styrene-Butadiene-Styrene (SBS) polymeric molecular chains so-called 1101AT and D0243, used to modify a 50/70 pen grade neat asphalt binder sample, generating the matrixes 60/85 E and Highly Modified Asphalt (HiMA), respectively. Some research gaps still exist and need to be investigated further, principally on why and how these distinct molecular chains influence the rheological-mechanical behavior of the asphalt binders and asphalt mixes, even pertaining to the same polymeric group. Dynamic Shear Rheometric (DSR) analyses describe the rheological spectra of the binder samples, considering the dynamic stiffness modulus in the complex plane |G*|. Porous asphalt mixes were evaluated considering the French formulation methodology and the following aspects: compaction ability, deleterious action of water, seepage speed and resistance to rutting. The results obtained indicate that HiMA matrix presented superior long-term rheological and mechanical behavior compared to 60/85 E, due to the more elaborate polymeric chain being associated to a bituminous matrix with rheological spectra providing less thermal and kinetic susceptibility, although its highest dynamic viscosity implies little reduction in the air void content and, consequently, lower seepage speeds to the porous asphalt mixes, but greater rutting resistance.

Synthesis, Structural, Magnetic and Computational Studies of a One-Dimensional Ferromagnetic Cu(II) Chain Assembled from a New Schiff Base Ligand

A new asymmetrically substituted ONOO Schiff base ligand N-(2′-hydroxy-1′-naphthylidene)-3-amino-2-naphthoic acid (nancH2) was prepared from the condensation of 2–hydroxy–1–naphthaldehyde and 3–amino–2–naphthoic acid. nancH2 reacts with Cu2(O2CMe)4·2H2O in the presence of Gd(O2CMe)3·6H2O to afford a uniform one-dimensional homometallic chain, [CuII(nanc)]n (1). The structure of 1 was elucidated via single crystal X-ray diffraction studies, which revealed that the Cu(II) ions adopt distorted square planar geometries and are coordinated in a tridentate manner by an [ONO] donor set from one nanc2− ligand and an O− of a bridging carboxylate group from a second ligand. The bridging carboxylato group of the nanc2− ligand adopts a syn, anti-η1:η1:μ conformation linking neighboring Cu(II) ions, forming a 1D chain. The magnetic susceptibility of 1 follows Curie–Weiss law in the range 45–300 K (C = 0.474(1) emu K mol-1, θ = +7.9(3) K), consistent with ferromagnetic interactions between S = ½ Cu(II) ions with g = 2.248. Subsequently, the data fit well to the 1D quantum Heisenberg ferromagnetic (QHFM) chain model with g = 2.271, and J = +12.3 K. DFT calculations, implementing the broken symmetry approach, were also carried out on a model dimeric unit extracted from the polymeric chain structure. The calculated exchange coupling via the carboxylate bridge (J = +13.8 K) is consistent with the observed ferromagnetic exchange between neighbouring Cu(II) centres.

Acid and alkali chemical treatments on synthetic and natural cellulosic, fibroin and keratin-based fabrics: study of structural changes

The characterization of fabrics after applying different degradation conditions appears to be a key factor to understand their behaviour for different applications. Depending on the treatment, morphologic and polymorphic changes may arise in the polymeric chain structure that composes textile fibers. In this paper, a systematic and comparative study between different types of natural and synthetic textile fabrics was carried out in order to shed light on the structural changes occurring under acid and alkali treatments. The natural fabric polymers studied had a cellulose-based composition from plants (cotton, linen and jute), or a protein-based one from animals (silk and wool). The synthetic fabric was polyester. Different treatment times were assessed: 15 min, 1, 2, 4, 8 and 24 h and compared to the initial condition of the fabrics (standard). In the cellulosic fabrics, the alkali provoked the polymorphic transformation of the amorphous CI into CII. However, the acid treatment did not cause any remarkable alteration in the structure. In protein fabrics, the acid treatment increased the amorphicity of the structures, leading to further degradation but not affecting the conformation of proteins, and the alkali dissolved the fabrics. Polyester was not affected by the chemical solutions (neither acid nor alkali).

Dually stimulative single-chain polymeric nano lock with dynamic ligands for sensitive detection of circulating tumor cells

Circulating tumor cells (CTCs) are important markers for cancer diagnosis and monitoring. However, CTCs detection remains challenging due to their scarcity, where most of the detection methods are compromised by the loss of CTCs in pre-enrichment, and by the lack of universal antibodies for capturing different kinds of cancer cells. Herein, we report a single-chain based nano lock (SCNL) polymer incorporating dually stimulative dynamic ligands that can bind with a broad spectrum of cancer cells and CTCs overexpressing sialic acid (SA) with high sensitivity and selectivity. The high sensitivity is realized by the polymeric single chain structure and the multi-valent functional moieties, which improve the accessibility and binding stability between the target cells and the SCNL. The highly selective targeting of cancer cells is achieved by the dynamic and dually stimulative nano lock structures, which can be unlocked and functionalized upon simultaneous exposure to overexpressed SA and acidic microenvironment. We applied the SCNL to detecting cancer cells and CTCs in clinical samples, where the detection threshold of SCNL reached 4 cells/mL. Besides CTCs enumeration, the SCNL approach could also be extended to metastasis assessment through monitoring the expressing level of surface SA on cancer cells.

Exploring dithiolate-amine binary ligand systems for the supramolecular assemblies of Ni(II) coordination compounds: Crystal structures, theoretical studies, cytotoxicity studies, and molecular docking studies

Dithiolate-amine binary ligand systems based two novel supramolecular structures of Ni(II) coordination compounds [Ni(2-ap)2(i-mnt)] (1) and [Ni2(i-mnt)2(tn)2]n (2) [where i-mnt−2: 1,1-dicyanoethylene-2,2-dithiolate, 2-ap: 2-amino pyridine, tn: 1,3-diaminopropane] have been designed, synthesized and characterized by spectroscopic techniques and X-ray crystallography. In complex 1, the N2S2 coordination kernel around Ni+2 attains distorted square planar geometry (Okuniewski parameter τ/4 = 0.17) and its supramolecular array has a dominant influence of N H···N type hydrogen bonds forming significant ring geometry of graph-set-motifR428. The i-mnt−2 adopts a diverse coordination mode in 2 contrary to 1 resulting in a binuclear one-dimensional infinite polymeric chain structure of consecutive NiS4 [square planar, S4 donor set τ/4 = 0] and NiN6 (octahedral) coordination kernels linked by i-mnt−2 that runs along [1 0 0] axis wherein N H···S, N H···N, C H···S type hydrogen bonds are believed to be crystal structure stabilizers. The Hirshfeld surface analyses (HS) at the molecular and atomic levels have been extensively studied to quantify all non-covalent interactions/contacts and the nature of ligand - metal interactions. The prominent N···H/H···N [28.1 % (1), 27.3 % (2A, NiS4), 20 % (2B, NiN6)] and S···H/H···S contacts [10.4 % (1), 32.8 % (2A), 29 % (2B)] presumably play vital role in crystal packing. The non-covalent interactions were further investigated by Molecular Electrostatic Potential (MEP) surface at PBE0-D3/def2-TZVP level and QTAIM optimizations (for 1). The MTT assay study using SW620 metastatic colon cancer cells shows a significant dose-dependent decline in cell proliferation with increasing concentration for 1 but for 2, the reverse trend is followed. A molecular docking study with the APC protein has further investigated the antiproliferative activity of 1 (MTT assay).

Floating-separation adsorbent for methylene blue and Pb(II) removal: Structure construction and adsorption mechanism

Inferior solid–liquid separation behavior and inadequate adsorption capacity are the main bottlenecks of current wastewater treatment adsorbents, especially in the purification of wastewater containing dyes and heavy metals. Accordingly, a novel floating separation adsorbent with polymeric chain structure, hollow glass sphere-g-(3-aminopropyl) triethoxysilane-g-poly(2-acrylamide-2-methyl-1-propanesulfonic acid) (APHGS-g-P(AMPS)), was fabricated through an electrophilic addition post-grafting strategy. The obtained APHGS-g-P(AMPS) exhibited satisfactory adsorption for methylene blue (MB) and lead ion (Pb(II)), as well as efficient flotation. Adsorption behavior analysis showed that the Pseudo-second-order kinetic model and Langmuir isotherm model were suitable for describing the adsorption process, and the maximum adsorption capacities for MB and Pb(II) were 249.33 and 345.93 mg·g−1 (313.15 K), respectively. Analysis of the adsorption mechanism indicated that the sulfonic acid group exhibited excellent universal adsorption for MB and Pb(II), which played a crucial role in the adsorption process. Furthermore, the efficient grafting of P(AMPS) polymerized chains onto the adsorbent was the pivotal factor to enhance adsorption. This study provided an efficient electrophilic addition post-grafting strategy for the structural design and functional modification of floating separation adsorbents. The results of this study are expected to have positive implications for the efficient purification of dyes and heavy metals wastewater.

Synthesis, crystal structure, DFT studies and Hirshfeld surface analysis of Manganese(II) and Cadmium(II) coordination polymers of 2-aminopyridine and dicyanamide

Mn(II) and Cd(II) metal salts reacted with dicyanamide and 2-aminopyridine resulted in the formation of the ligand-rich linear polymeric chain structures [M(dca)2(2-Ampy)2]n (dca = dicyanamide, 2-Ampy = 2-Aminopyridine; M = Mn (1) or Cd (2)), of the same dimensionality, in which the metal centers are μ1,5-bridged by the dca anions. The complexes were characterized by elemental analysis, IR spectroscopy, UV–vis spectroscopy, thermal analysis and single crystal X-ray structure analysis. These coordination polymers crystallize in the Monoclinic space group Cc. The 3D crystal packing structure results from a combination of N—H/H—-N interactions followed by CH—π stacking interactions. Hirshfeld surface (HS) analysis of the polymers was undertaken to investigate further the intermolecular interactions. DFT calculations on 1 and 2 demonstrated a good correlation between the experimental and theoretical data. The in vitro antimicrobial activity of the manganese complex against selected micro-organisms is also reported.

Effect of mechanically modification process on boron carbide synthesis from polymeric precursor method

In this study, a polymeric precursor was synthesized from industrial raw materials by the sol-gel method. The organic components in the polymeric chain structure were separated with the calcination process, and a reactant consisting of carbon and B2O3 was obtained. Mechanically modification process was applied to the reactant by a ball milling, which changed the structure of the reactant. It was observed that this process promoted the crystallinity and decreased the particle size of the reactant. In addition, the bimodal structure of the reactant was transformed to a bicontinuous structure. The reactant and a mechanically modified carbon-based reactant (MMCBR) were applied to heat treatment at 1400–1700 °C for 5 h under argon gas to investigate the effect of mechanically modification process on final products. A non-uniform powder morphology with polyhedral and rod-shaped B4C particles was obtained from reactant and MMCBR. While the B4C powder obtained from the reactant was agglomerated, no agglomeration was observed at the B4C powder obtained from MMCBR. As a result, the B4C powder synthesized in this fashion contained less free carbon as compared to that prepared with MMCBR.

Synthesis of polymeric CdS and its optical properties investigation

Producing of polymeric cadmium sulfide in polyvinyl alcohol matrix is reported. The result was achieved through solid state sulfurization of hybrid interpolymeric complex of polyvinyl alcohol with cadmium chloride. In this process CdS inherits polymeric chain structure of CdCl2 complexing with polyvinyl alcohol due to diffusion restriction. One-dimensional structure of CdS was verified by high degree of luminescence polarization and Raman spectra behavior. It was observed that Raman spectrum of produced material is similar to spectrum of polyacetylene. This similarity disappears at impurities addition. Appearance of Raman band at 228 cm-1 indicates formation of CdS chain structure. Resulting polyvinyl alcohol --- CdS system has a structure of Little's high temperature superconductor. Keywords: one-dimensional structures, inorganic polymers, conjugated polymers, hybrid polymeric complexes, polyvinyl alcohol, CdS.

Synthesis of luminescent phosphine-containing rigid-rod dinuclear alkynylgold(I) complexes and their X-Ray structural, photophysical, self-assembly and electroluminescence studies

A series of rigid-rod dinuclear alkynylgold(I) complexes bearing triethylene glycol monomethyl ether or dibutoxy-substituted oligo(p-phenylene ethynylene)s moieties as the backbone, and phosphine ligands that are charge-neutral or bear a positive or negative charge, has been designed and synthesized. The alkynylgold(I) complexes with charge-neutral phosphines are found to show polymeric zig-zag chain structure with short gold‧‧‧gold distances in their X-ray crystal structures, while those with negatively charged phosphine ligands demonstrate spherical aggregates in dimethyl sulfoxide (DMSO)-water dispersions. The aggregation behaviour of the complex with positively charged phosphine ligand is found to follow an isodesmic mechanism upon increasing the water content in DMSO. Representative complexes have been applied as the emitting material in solution-processed organic light-emitting devices, exhibiting sky-blue emission with emission maxima at 432 nm. This work has provided further insights into the aggregation behaviour of this class of alkynylgold(I) complexes, as well as the understanding of their molecular packing and alignment for the future design of structurally-related rigid-rod organometallic materials.

Synthesis and crystal structure of a one-dimensional chain-like strontium(II) coordination polymer built of N-methyldi-ethano-lamine and isobutyrate ligands.

The one-dimensional coordination polymer (I) [Sr(ib)2(H2mda)] n (Hib = isobutyric acid, C4H8O2, and H2mda = N-methyldi-ethano-lamine, C5H13NO2), namely, catena-poly[[(N-methyldi-ethano-lamine-κ3 O,N,O')strontium(II)]-di-μ2-isobutyrato-κ3 O,O':O;κ3 O:O,O'], was prepared by the one-pot aerobic reaction of [Zr6O4(OH)4(ib)12(H2O)]·3Hib with Sr(NO3)2 and H2mda in the presence of MnCl2 and Et3N in aceto-nitrile. The use of MnCl2 is key to the isolation of I as high-quality colorless crystals in good yield. The mol-ecular solid-state structure of I was determined by single-crystal X-ray diffraction. Compound I crystallizes in the monoclinic space group P21/c and shows a one-dimensional polymeric chain structure. Each monomeric unit of this coordination polymer consists of a central SrII ion in the NO8 coordination environment of two deprotonated ib- ligands and one fully protonated H2mda ligand. The C and O atoms of the H2mda ligand were refined as disordered over two sets of sites with site occupancies of 0.619 (3) and 0.381 (3). Compound I shows thermal stability up to 130°C in air.

A One‐Dimensional Cadmium Coordination Polymer: Synthesis, Structure, and Application as Luminescent Sensor for Cu2+ and CrO42−/Cr2O72− Ions

AbstractA novel coordination polymer {[Cd4(CPIP)3Cl8]}n (CP1) was constructed from the reaction of CPIP (CPIP=1‐chloro‐3‐(pyridine‐2‐yl)imidazo[1,5‐a]pyridine) and CdCl2⋅2.5H2O under solvothermal conditions. The employment of CPIP as the ligand was based on the consideration that two types of Lewis basic sites (the fused nitrogen atom and the chlorine substituent) are present on the backbone of the ligand. These sites can be utilized for interacting with cations and anions, thus for the sensing functionality. Single‐crystal X‐ray diffraction studies revealed that CP1 exhibits interesting one‐dimensional (1D) polymeric chain structure. The adjacent four CdII ions are connected by one μ3‐Cl and five μ2‐Cl atoms to form a Chinese‐lantern‐like topology. CP1 is an excellent luminescent sensor for detecting Cu2+, CrO42− and Cr2O72− ions with high selectivity, sensitivity, and recyclability. Moreover, CP1 is the first reported chloride‐bridged coordination polymer that is capable of sensing Cu2+ ion. The mechanisms for sensing Cu2+, CrO42− and Cr2O72− ions were investigated and discussed.

Lithium calix[4]arenes: structural studies and use in the ring opening polymerization of cyclic esters.

We have structurally characterized a number of lithiated calix[4]arenes, where the bridge in the calix[4]arene is thia (–S–, LSH4), sulfinyl (–SO–, LSOH4), sulfonyl (–SO2–, LSO2H4), dimethyleneoxa (–CH2OCH2–, LCOCH4) or methylene (–CH2–, LH4). In the case of L4SH4, interaction with LiOtBu led to the isolation of the complex [Li8(L4S)2(THF)4]·5THF (1·5THF), whilst similar interaction of L4SOH4 led to the isolation of [Li6(L4SOH)2(THF)2]·5(THF) (2·5THF). Interestingly, the mixed sulfinyl/sulfonyl complexes [Li8(calix[4]arene(SO)(SO2)(SO1.68)2)2(THF)6]·8(THF) (3·8THF) and [Li5Na(LSO/3SO2H)2(THF)5]·7.5(THF) (4·7.5(THF) have also been characterized. Interaction of LiOtBu with LSO2H4 and LCOCH4 afforded [Li5L4SO2(OH)(THF)4]·2THF (5·2THF) and [Li6(LCOC)2(HOtBu)2]·0.78THF·1.22hexane (6·0.78THF·1.22hexane), respectively. In the case of LH4, reaction with LiOtBu in THF afforded a monoclinic polymorph [LH2Li2(thf)(OH2)2]·3THF (7·3THF) of a known triclinic form of the complex, whilst reaction of the de-butylated analogue of LH4, namely de-BuLH4, afforded a polymeric chain structure {[Li5(de-BuL)(OH)(NCMe)3]·2MeCN}n (8·2MeCN). For comparative catalytic studies, the complex [Li6(LPr)2(H2O)2]·hexane (9 hexane), where LPr2H2 = 1,3-di-n-propyloxycalix[4]areneH2, was also prepared. The molecular crystal structures of 1–9 are reported, and their ability to act as catalysts for the ring opening (co-)/polymerization (ROP) of the cyclic esters ε-caprolactone, δ-valerolactone, and rac-lactide has been investigated. In most of the cases, complex 6 outperformed the other systems, allowing for higher conversions and/or greated polymer Mn.

Synthesis, crystal structures, fluorescence, and magnetic properties of 1,3,5-benzenetricarboxylate coordination polymers

Four new coordination polymers, {[Mn3(BTC)2(4-pp)6(H2O)2]·(4-pp)2(H2O)2}n 1, [Cu3(BTC)2(dpa)2]n 2, {[Zn3(BTC)2(4-pp)6]·(H2O)}n 3, and [Ag2(HBTC)(Pz)1/2]n 4, were synthesized under pH-controlled solvothermal conditions with symmetrical polycarboxylic acid of 1,3,5-benzenetricarboxylic acid (H3BTC) and nitrogen-containing heterocyclic compounds, pyrazine (pz), 4-phenylpyridine (4-pp), and 4,4′-dipyridylamine (dpa). Complexes 1–4 were characterized by single-crystal X-ray diffraction, elemental analysis, IR spectra, powder X-ray diffraction, thermal gravimetric analysis, photoluminescence, and magnetic susceptibility. Complexes 1 and 3 show two-dimensional (2-D) layered structures, 2 exhibits a three-dimensional (3-D) network structure, and 4 is a one-dimensional (1-D) polymeric chain structure. Magnetic susceptibility measurements indicate that 1 shows weak antiferromagnetic coupling between MnII ions and 2 exhibits ferromagnetic interaction between CuII ions. The photoluminescence properties of 3 and 4 are similar to the ligand H3BTC.