Bpe Ligands Research Articles

Exploring a prototype for cooperative structural phase transition in cobalt(II) spin crossover compounds.

The creation of magnetically switchable materials that concurrently incorporate spin crossover (SCO) and a structural phase transition (SPT) presents a significant challenge in materials science. In this study, we prepared four structurally related cobalt(II)-based SCO compounds: two one-dimensional (1D) chains of {[(enbzp)Co(μ-L)](ClO4)2·sol}n (L = bpee, sol = 2MeOH·H2O, 1; L = bpea, sol = none, 2; enbzp = N,N'-(ethane-1,2-diyl)bis(1-phenyl-1-(pyridin-2-yl)methanimine); bpee = 1,2-bis(4-pyridyl)ethylene; and bpea = 1,2-bis(4-pyridyl)ethane) and their discrete segments, [{(enbzp)Co}2(μ-L)](ClO4)4·2MeOH (L = bpee, 3; L = bpea, 4). In all of these complexes, each Co(II) center is equatorially chelated by the planar tetradentate ligand enbzp and connected to a chain or dinuclear structure through bpee or bpea ligands along its axial direction. All of the complexes, including their desolvated phases, displayed overall incomplete and gradual SCO properties. Interestingly, the desolvated phase of 1 exhibited an additional non-spin magnetic transition characterized by wide room-temperature hysteresis (>40 K), which was reversible and rate-dependent, showcasing the synergy between SCO and SPT manifested through slow kinetics. We discuss the possible reasons for the distinct features and our findings demonstrate that the combination of a rigid polymeric framework with flexible substituents holds promise for achieving synergy between SCO and SPT.

Exploring enantioselective recognition of dTMP-Co-bpe coordination polymer for natural amino acids using molecular simulations and circular dichroism.

The 1D homochiral coordination polymer (CP-1) {[Co(dTMP)(bpe)2(H2O)3]·9H2O}n was constructed by using 2'-deoxy thymidine 5'-monophosphate disodium salt (dTMP·2Na), and auxiliary ligand bpe (1,2-bis(4-pyridyl)ethene) and characterized by single-crystal XRD, PXRD, IR, UV-visible, CD and TGA analyses. Molecular simulations revealed the selective chiral behaviour of CP-1 towards phenylalanine and histidine, as indicated by their higher binding free energies compared to other amino acids. Theoretical parameters were also compared with experimental UV-visible verdicts. Notably, the D-enantiomers of phenylalanine and histidine demonstrated strong bonding abilities and optimal configurations for probing and distinguishing them from their L-counterparts. These findings led to propositions suggesting that the dissimilarities between these D and L amino acid forms and their binding orientations with CP-1 may contribute to alterations in the CD signal. CP-1 exhibited a robust inherent circular dichroism (CD) signal in aqueous solutions, modulated by the presence of specific amino acids, namely D/L phenylalanine and D/L histidine. Leveraging the measurement of CD signal intensity, a sensor capable of detecting unmodified amino acids has been developed. Unlike previously reported approaches that relied on complex chemical reactions between initially CD-silent molecules and probed amino acids, this new method offers a more straightforward means of amplifying the CD signal. Consequently, this change facilitates a more accurate differentiation between the enantiomers of these specific amino acids compared to others.

The syntheses, structural and biological studies of Co(II) complexes of 1,2-Bis(pyridin-4-yl)ethane with 2-aminobenzene-1,4-disulfonic acid and 2,6-pyridinedicarboxylic acid

The newly synthesized salt named 4,4′-(ethane-1,2-diyl)bis(pyridin-1-ium) 2-aminobenzene-1,4-disulfonate, (H2BPE)2+(ADSA)2− (1), was prepared from the reaction of 1,2–bis(pyridin–4–yl)ethane (BPE) and 2–amino-benzene–1,4–disulfonic acid (H2ADSA). Two new metal complexes of 4,4′-(ethane-1,2-diyl)bis(pyridin-1-ium) 2-aminobenzene-1,4-disulfonate were also synthesized: The first complex [Co(BPE)2(H2O)4](ADSA).BPE (2) has been synthesized from the obtained proton transfer salt (1). The second complex, {[Co(BPE)(H2O)4]}n[Co(DPC)2].2H2O (4), is a one–dimensional coordination polymer and was synthesized using proton transfer salt (H2BPE)2+(DPC)2- (3). Elemental analysis, Nuclear Magnetic Resonance, Infrared and Ultraviolet–Visible spectra methods were used to elucidate the structure of 1. Elemental analysis, magnetic moment measurements, spectral (UV–Vis, AAS and IR) and X–ray crystallographic analysis were applied for structural manalysis of 2 and 4. X–ray crystallographic study for 2 and 4 revealed that in both complexes the BPE coordinated the Co(II). In compound 2, the coordination periphery of the Co(II) consists of two nitrogens from two BPE, four oxygens from four H2O molecules and forms the six–coordinated octahedral geometry. X–ray crystallographic analysis of 4 showed that the complex was polymer and the metal ions were linked by BPE ligand bridges. The molecular structure of coordination polymer 4 contains both cationic and anionic complexes, each with an octahedral geometry. The coordination sphere of the cationic complex consists of two nitrogens of two BPE and four oxygens of four aqua molecules. On the other hand, the two DPC2− ligands contribute two nitrogens and four oxygens to the coordination sphere of the anionic complex. The antibacterial and antifungal capabilities of the produced compounds were further investigated, and the MIC (Minimum Inhibitory Concentration) values were compared to those of related control substances.

Output Enhancement of Triboelectric Nanogenerators Based on Hierarchically Regular Cadmium Coordination Polymers for Photocycloaddition.

Exploiting the well-arranged and tunable frameworks of crystalline materials, we herein report coordination polymers (CPs) with modulated hierarchical structures as triboelectric materials to construct and extend the application scope of triboelectric nanogenerators (TENGs). Different lengths and shapes of bridging ligands [4,4'-bpa = 1,2-bis(4-pyridyl)ethane, 4,4'-bpe = 1,2-bis(4-pyridyl)ethene, and 4,4'-bpp = 1,3-di(2-pyridyl)propane for 1, 2, and 3, respectively] were used to construct Cd-CP-based hierarchical frameworks. These compounds were used as triboelectric materials, and their electronic structure contributions were determined by the output of the corresponding TENGs. The results indicated that 2-TENG with the 4,4'-bpe ligand had the highest output, attributed to the improvement in the electron activity due to the π-conjugation group in the bridging ligand, which was further verified by density functional theory calculations. Furthermore, 2@PVDF (PVDF = polyvinylidene fluoride) composite films with different concentrations of Cd-CP were prepared. Detailed electrical characterizations revealed that the arrangement of 12% active constituents of Cd-CP-2 effectively enhanced the output performance of 2@PVDF-TENG, which could light up an ultraviolet lamp plate to successfully execute the [2 + 2] photocycloaddition.

Homochiral coordination polymers based on proline-derivative: structures, magnetic properties, and selective detection of Cr2O72− anion

By incorporating semi-rigid terephthaloyl mono proline-derived ligand [H2TMPro ​= ​terephthaloyl-mono(l-proline)] with the ancillary dipyridyl ligands [bpea ​= ​1,2-bis(4-pyridyl)ethane and bipy ​= ​4,4′-bipyridine], five new homochiral coordination polymers were synthesized. Compounds [Cu3(TMPro)2(μ3-OH)2]·4H2O (1) and [Zn3(TMPro)2(μ3-OH)2]·4H2O (2) are isostructural complicated 3D frameworks, which contain the intertwined right- and left-handed helical chains built from the butterfly-shaped [Cu4(μ3-OH)2(RCOO)6] units. Compound [Cu2(TMPro)2(bpea)2(H2O)2]·7H2O (3) displays a 3D framework composed of Cu1-TMPro left-handed helical chains and Cu2-TMPro right-handed helical chains connected by the bpea ligands. Compound [Cd4(TMPro)4(bpea)6]·10H2O·4C2H5OH (4) features a 3-fold interpenetrating 3D framework with 5-connected hexagonal bnn topological net constructed from the {Cd-TMPro} chains and bpea ligands. Compound [Ni(TMPro)(bipy)(H2O)3] (5) exhibits a {Ni-bipy}2+ 1D chain decorated by the TMPro2− anions. Magnetic susceptibility measurements indicate ferromagnetic exchange interactions between Cu(II) ions in 1. Photoluminescence spectra of 2 show corresponding emission bands of TMPro2− anions. Additionally, for 2, the Ksv value of 553 ​M−1 and detection limit of 70 ​μM imply it can detect the Cr2O72− anion.

Ir-catalyzed asymmetric hydrogenation of ketones using novel PNO phosphine ligands

<p indent=0mm>The asymmetric hydrogenation of ketones continue to be a hot research topic because of the importance of secondary chiral alcohols in the production of pharmaceuticals and many other products. For example, based on the asymmetric hydrogenation of ketones, our group has synthesized Duloxetine and Ezetimibe, which were important and best selling antidepressant and antihyperlipidemic drugs. On the other hand, phosphine ligands were found to be the critical factor to increase the activity of metal catalysts. Thus, since the successful application of BINAP by Noyori and co-workers, hundreds of phosphine ligands have been developed for the more efficient transformation of ketones into chiral alcohols. For example, BPE ligand reported by Burk group in 1993, Miniphos ligand synthesized by Imamoto and coworkers in 1999, series of SDP ligands developed by Zhou group since 2002, were both efficient and successful ligands for the asymmetric transformation of different ketones. Since 1997, our group also contributed many improved ligands for this reaction, such as, Binapine, f-amphox, et al. Despite significant achivements, there are still some questions to be solved in this area. For example, the synthesis of needed ligands demands hash reaction conditions and expensive starting materials, and sometimes the purification of the corresponding ligands was hard. Thus, new ligands or new synthetic methods are still in need for the more efficient transformation. Recently, we got interested in the introduction of prolinols as building blocks for the modification of ligands to control the enantioselectivity of this transformation. As a class of commercial available chiral building blocks, prolinol and its derivatives were increasingly applied as ligands or additives in the controls of enantioselectivity of organic transformations. In this context, combining our long standing interests in the developing of ferrocene based ligands, we designed and synthesized some novel PNO type phosphine ligands through three simple steps. Notably, the applied starting materials for these ligands were both commercially available chiral building blocks. The corresponding ligands have the advantages of easily available starting material, convenient synthesis, and simple purification. With these ligands in hand, we tested their catalytic activity on Ir-catalyzed asymmetric hydrogenation of acetophenone, which gave 99% conversion and high ee value of the product. Encourage by these positive result, we further optimized the reaction conditions including the solvent, base species, H₂ pressure, and the catalyst loading. THF was the best solvent among the test solvents. Since most of the tested base species giving similar results, we assumed base has only slight effect on both the conversion of acetophenone and the enantioselectivity of corresponding product. In some additional reaction conditions screening experiments, we found that a higher H₂ pressure or a higher catalyst loading was favorable for the conversion of acetophenone and the enantioselectivity of corresponding product. Thereafter, various different ketones were tested using the optimal reaction conditions. This catalytic system was compatible well with halides substitutions, methoxy gourps, and -CF₃ gourps, and also possible for the application in the transformation of heterocycles. Herein, an efficient and practical protocol was developed for the asymmetric hydrogenation of ketones. The proposed catalytic system gave the corresponding chiral secondary alcohols in up to >99% yield, 99% ee, and 100000 TON. In view of the high efficiency and easy synthesis of the ligand, we assume this work has remarkable potential regarding industrial process in the near future.

Poly[[[μ-trans-1,2-bis-(pyridin-4-yl)ethene-κ2 N:N']-μ-iodido-copper(I)]-trans-1,2-bis-(pyridin-4-yl)ethene (1/0.25)

The title compound, {[CuI(bpe)]·0.25(bpe)} n , was synthesized similarly to (CuI)2(bpe) [Neal et al. (2019 ▸). IUCrData, 4, x190122] with red crystals grown from aceto-nitrile solutions of CuI and the bpe ligand [bpe = 1,2-bis-(pyridin-4-yl)ethene, C12H10N2]. The structure of the title compound is a type 1 complex in the Graham nomenclature [Graham et al. (2000 ▸). Inorg. Chem. 39, 5121-5132], having rhombic dimers of Cu2I2 that are bridged by two bpe ligands, to form oligomeric ribbons arranged as stairsteps. The step height is 2.8072 (11) Å, which is the Cu-Ii distance of the dimer [symmetry code (i): 1-x, 2-y, 1-z]. The resulting polymer displays a two-dimensional honeycomb framework along the (01) plane, and disordered free bpe mol-ecules fill the voids in the crystal.

Two new Zn2+/Cd2+ Metal-Organic Frameworks (MOFs) constructed from asymmetrical tricarboxylic acid ligands

Two new Metal-Organic Frameworks (MOFs), namely, [Cd(HL1)(H2O)] 1, [H2(bpp)][Zn2(L2)2(bpe)]·2H2O 2 (H3L1 = 4-(5-carboxy-pyridine-3-yloxy)-phthalic acid, H3L2 = 3-(4-carboxy-phenoxy)-phthalic acid, bpe = 1,2-bis(4-pyridyl) ethylene, bpp = 1,3-bis(4-piperidyl) propane) have been isolated employing two V-shaped asymmetric tricarboxylic acid ligands under hydrothermal conditions. X-ray single-crystal diffraction analysis reveals that μ4-mode HL12− molecules propagate the Cd2+ centers into a 3-D network with point symbol of 66 for 1. One-dimensional channels are observed in 1, but because of 2-fold interpenetration phenomenon, these channels become small or disappear. 2 possesses a 2-D layered structure with (3, 4)-connected (42ˑ63ˑ8) (42ˑ6) topology. The carboxyl moieties for L2 molecules first extend the Zn2+ centers into a 1-D double chain, then via the interactions between Zn2+ and pyridine N atoms, the resulting 1-D double chain are strutted by the rigid bpe ligands to form a 2-D layer framework. It is noteworthy that one-dimensional channels of ca. 13 × 13 Å2 are observed. H2(bpp)2+ and two lattice water molecules occupy the space of the channels. The introduced bpp molecules only serve as the templating agent and are not involved in the formation of this layer network. The photoluminescence properties of 1 and 2 were investigated.

Photochemically Tuned Magnetic Properties in an Erbium(III)-Based Easy-Plane Single-Molecule Magnet.

The magnetic properties of single-molecule magnets can be controlled by external conditions such as light, pressure, and temperature. Among these conditions, photochemical control is the best approach due to the accessibility and rapid conduction of light. In this work, an Er(III)-based complex with photoactive ligand bpe, [Er(nat)3·MeOH·bpe] (1, bpe = 1,2-bis(2-pyridyl)ethylene, nat = 4,4,4-trifluoro-1-(2-naphthyl)-1,3-butanedione), was synthesized. The auxiliary ligand nat and cyclized ligand bpe stacked reasonably in the crystal structure. Two molecules of 1 experienced the [2, 2]-cycloaddition reaction under the UV irradiation in the solid state and [{Er(nat)3MeOH}2(tpcb)] (2, tpcb = tetrakis(4-pyridyl)cyclobutane) was produced. The slight change in the structure around Er(III) ions leads to the different magnetic properties, which illustrates the photochemical control of the magnetic properties of single-molecule magnets.

Cobalt(II)-coordination polymers containing glutarates and bipyridyl ligands and their antifungal potential

Three new CoII-coordination polymers (Co-CPs) containing glutarates and bipyridyl ligands, formulated as [Co2(Glu)2(µ-bpa)2]·(H2O)4 (1), [Co4(Glu)4(µ-bpp)2] (2), and [Co2(Glu)2(µ-bpe)2]·(H2O)0.5 (3), were prepared, and their structures were determined by X-ray crystallography. Glutarates bridge CoII ions to form 2D sheets, and the sheets are connected either by bpa or by bpp ligands to form 3D networks 1 and 2, respectively. Both frameworks 1 and 2 are two-fold interpenetrated, and there is no significant void volume in either network. Four glutarates bridge two CoII ions to form chains, and these chains are connected by bpe ligands to form the 2D sheet 3. The antifungal properties of these new Co-CPs were tested against two model fungal pathogens, Candida albicans and Aspergillus niger. Under the maximum concentration of Co-CPs, 2.0 mg mL−1, the inhibition rates of Co-CPs against A. niger were much lower (44–62%) than those (90–99.98%) observed in C. albicans. The results indicate that 1–3 can inactivate C. albicans cells more efficiently than A. niger spores in the same treatment time, and the greater inactivation of C. albicans can be explained by dramatic changes in the morphology of C. albicans cells. We also found that Co-CPs could generate the reactive species NO and H2O2, and these species might play a role in inactivating fungal cells. Additionally, degradation tests confirmed that the leaching of CoII ions from Co-CPs was not significant. The small amount of leached CoII ions and the robust Co-CPs themselves as well as the reactive species generated by Co-CPs can actively participate in fungal inactivation.

Multifunctional Polymolybdate-Based Metal-Organic Framework as an Efficient Catalyst for the CO2 Cycloaddition and as the Anode of a Lithium-Ion Battery.

A three-dimensional polymolybdate-based metal-organic framework (POMOF) consisting of Zn-ε-Keggin unit and organic linker, {[PMo8VMo4VIO37(OH)3Zn4][BPE]2}·[BPE] (1), was successfully obtained by the hydrothermal method. Compound 1 is composed of Zn-ε-Keggin units and BPE ligands, featuring a fascinating 5-fold interpenetrating framework with dia topology. The catalytic performance of compound 1 was investigated, and experiments showed that 1 could effectively facilitate the cycloaddition reaction of CO2 with epoxides as Lewis acid heterogeneous catalyst. Moreover, compound 1 also was studied as LIBs anode material, and it showed reversible capacity of 546 mA h g-1 at 100th cycle.

Single-Crystal-to-Single-Crystal Transformation of Hydrogen-Bonded Triple-Stranded Ladder Coordination Polymer via Photodimerization Reaction.

A one-dimensional hydrogen-bonded triple-stranded ladder coordination polymer [Cd(bpe)1.5(NO3)2(H2O)] (1) (where bpe = trans-1,2-bis(4-pyridyl)ethylene) containing three parallel C═C double bonds was synthesized. This compound undergoes photochemical [2 + 2] cycloaddition and produces rctt-tetrakis(4-pyridyl)cyclobutane (rctt-tpcb) in up to 67% yield via Single-Crystal-to-Single-Crystal (SCSC) transformation. Triple-stranded ladder-like structures have never before displayed such a kind of SCSC transformation. Furthermore, photoirradiation of ground 1 produces rctt-tpcb in up to 100% yield in the solid state. On the basis of the alignment of three C═C olefinic bonds of bpe ligands in parallel, only two out of the three aligned bpe are expected to undergo [2 + 2] photodimerization. However, the quantitative yield from the solid-state photochemical [2 + 2] cycloaddition reaction has been achieved via grinding of crystals of 1 to a powder. The effects of grinding on photoreactivity of 1 were thoroughly studied using 1H NMR spectroscopy, thermogravimetric analysis (TGA), and Raman spectroscopy. These studies indicate that the molecular movements of the hydrogen-bonded ladders are reinforced due to the loss of coordinated water molecules and the further crystal repacking via bond-breaking/forming of the hydrogen-bonded assemblies during mechanical grinding. The 100% photodimerization of ground 1 shows that the grinding accelerates internal molecular motions of ladder structures within the crystals lattice. The solid-state photoluminescence of 1, before and after UV irradiation, was investigated at room temperature, both indicative of interesting luminescent properties.

Killing two birds with one stone: 2D+2D→3D parallel stacking and 3D self-penetrating structures in one reaction and their crystal-to-crystal transformation

Reaction of the flexible phenolic carboxylate ligand 2-(3,5-dicarboxylbenzyloxy)benzoic acid (H3L) with nickel salts in the presence of 1,2-bis(pyridin-4-yl)ethylene (bpe) leads to the generation of a mixture of the two complexes under solvolthermal conditions, namely poly[[aqua[μ-1,2-bis(pyridin-4-yl)ethylene-κ2N:N']{μ-5-[(2-carboxyphenoxy)methyl]benzene-1,3-dicarboxylato-κ3O1,O1':O3}nickel(II)] dimethylformamide hemisolvate monohydrate], {[Ni(C16H10O7)(C12H10N2)(H2O)]·0.5C3H7NO·H2O}n or {[Ni(HL)(bpe)(H2O)]·0.5DMF·H2O}n, 1, and poly[[diaquatris[μ-1,2-bis(pyridin-4-yl)ethylene-κ2N:N']bis{μ-5-[(2-carboxyphenoxy)methyl]benzene-1,3-dicarboxylato-κ2O1:O5}nickel(II)] dimethylformamide disolvate hexahydrate], {[Ni2(C16H10O7)2(C12H10N2)3(H2O)2]·2C3H7NO·6H2O}n or {[Ni2(HL)2(bpe)3(H2O)2]·2DMF·6H2O}n, 2. In complex 1, the NiII centres are connected by the carboxylate and bpe ligands to form two-dimensional (2D) 4-connected (4,4) layers, which are extended into a 2D+2D→3D (3D is three-dimensional) supramolecular framework. In complex 2, bpe ligands connect to NiII centres to form 2D layers with Ni6(bpe)6 metallmacrocycles. Interestingly, 2D+2D→3D inclined polycatenation was observed between these layers. The final 5-connected 3D self-penetrating structure was generated through further connection of Ni-carboxylate chains with these inclined motifs. Both complexes were fully characterized by single-crystal analysis, powder X-ray diffraction analysis, FT-IR spectra, elemental analyses, thermal analysis and UV-Vis spectra. Notably, an interesting metal/ligand-induced crystal-to-crystal transformation was observed between the two complexes.

One-Dimensional Self-assembled Coordination Polymer, {[Cu(bpy)(bpe)(NO3)2]·(H2O)4}n

Coordination polymer {[Cu(bpy)(bpe)(NO3)2]·(H2O)4}n (CP1) has been synthesized using [Cu(bpy)(NO3)2] (where bpy = 2,2′-bipyridine) and bpe (bpe = 1,2-bis(4-pyridyl)ethane as a spacer in equimolar ratio. CP1 was characterized by using Infrared spectroscopy, elemental analysis, and single crystal X-ray diffraction. The crystal structure confirms that the CP1 is formed with a bridging bpe linker giving rise to helical chain in one-dimensional (1D) structure. Copper ion is connected to two nitrogen atoms from bpy, two oxygen atoms from nitrate anions (major component) and two nitrogen atoms from two bpe ligands. There is an additional minor component which is five coordinate. The hydrogen bonding links the helical chains to generate a three dimensional (3D) network structure. A one-dimensional coordination polymer {[(Cu(bpy)(bpe)(NO3)2]·H2O)4}n (CP1) has been synthesized using [Cu(bpy)(NO3)2] (where bpy = 2,2′-bipyridine) as a building block and bpe (bpe = 1,2-bis(4-pyridyl)ethane) as a spacer in a equimolar ratio.

Homochiral Porous Metal–Organic Frameworks Constructed from a V-Shaped Alanine Derivative Based on Pyridyl-Dicarboxylate

Three novel, homochiral, porous metal–organic frameworks based on the H2PDBAla ligand and different divalent cations (Co(II)) and Cu(II)), namely, [M(PDBAla)(bipy)(H2O)2]·3H2O (M = Co 1 and Cu 2), [Cu(PDBAla)(bpea)]·7H2O (3) (H2PDBAla = pyridine-2,6-dicarbonyl-bis(l-alanine), bipy = 4,4′-bipyridine, bpea = 1,2-bis(4-pyridyl)ethane), have been synthesized and characterized with the assistance of N-donor ligands. The distinctive H2PDBAla ligands are coordinated to divalent metal ions by the different coordination modes, forming various helixes in compounds 1–3. Compounds 1 and 2 are isostructural and feature a 2-fold interpenetrating three-dimensional (3D) framework with the cds topological net built by the combination right-handed helical chains and bipy ligands, whereas a 3D framework with the tcj topological net is observed in compound 3, wherein bpea ligands reinforce the 3D framework constructed by right-handed helical chains. Compounds 1 and 3 display high CO2 absorption capability and superior sorpti...

Hydrogen bonding and π-π interactions in the cocrystal salt [Fe(bpe)2(H2O)4](TCEP)2·2(bpe) [bpe is trans-1,2-bis(pyridin-4-yl)ethene and TCEP is 1,1,3,3-tetracyano-2-ethoxypropenide

The cocrystal salt tetraaquabis[trans-1,2-bis(pyridin-4-yl)ethene-κN]iron(II) bis(1,1,3,3-tetracyano-2-ethoxypropenide)-trans-1,2-bis(pyridin-4-yl)ethene (1/2), [Fe(C12H10N2)2(H2O)4](C9H5N4O)2·2C12H10N2, is a rare example of a mononuclear FeII compound with trans-1,2-bis(pyridin-4-yl)ethane (bpe) ligands. The complex cation resides on a crystallographically imposed inversion center and exhibits a tetragonally distorted octahedral coordination geometry. Both the symmetry-independent bpe ligand and the cocrystallized bpe molecule are essentially planar. The 1,1,3,3-tetracyano-2-ethoxypropenide counter-ion is nonplanar and the bond lengths are consistant with significant electron delocalization. The extended structure exhibits an extensive O-H...N hydrogen-bonding network with layers of complex cations joined by the cocrystallized bpe. Both the coordinated and the cocrystallized bpe are involved in π-π interactions. Hirshfeld and fingerprint plots reveal the important intermolecular interactions. Density functional theory was used to estimate the strengths of the hydrogen-bonding and π-π interactions, and suggest that the O-H...N hydrogen bonds enhance the strength of the π-interactions by increasing the polarization of the pyridine rings.

A Zn(II)/anthracene coordination polymer showing highly efficient photocatalytic Cr(VI) reduction in aqueous solution

Reaction of Zn(OAc)2·2H2O with the visible light responsive organic ligand 9,10-bis(4′ -pyridylethynyl)-anthracene (BPEA) gave rise to a Zn(II)/anthracene coordination polymer [Zn(OAc)2(BPEA)]n. Compound 1 has a one-dimensional (1D) chain structure in which the binuclear {Zn2(OAc)2} cores are linked by the BPEA ligands using the pyridyl N atoms to give to the 1D ladder-like network. The as-prepared compound 1 shows broad-range visible light absorption and good water stability, which are highly demandable for its application in the photocatalysis. The photocatalytic property of 1 were investigated by reduction of Cr(VI) to Cr(III) in aqueous solution under visible light, which reveals its high efficiency and stability in this photocatalytic process.

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 one-dimensional self-assembled porous coordination polymer poly[bis(picolinato-N,O)(µ-1,2-bis(4-pyridyl)ethane-N,N′)cobalt(II)] dimethanol

A one-dimensional coordination polymer {[(Co(pic)2(bpe)]·2CH3OH}n(1) has been synthesized using [Co(pic)2(H2O)2]·2H2O where pic = picolinate as a building block and 1,2-bis(4-pyridyl)ethane (bpe) as an linker in a 1:1 M ratio. This compound was characterised by using elemental analysis, IR spectroscopy, thermogravimetric analysis and single crystal X-ray diffraction. Single crystal X-ray structural analysis revealed that the compound 1 formed by bridging bpe ligand which gives rise to the one-dimensional (1D) linear chain. In the crystal structure coordination sphere consists of two oxygen atoms and two nitrogen atoms of the two picolinato and two nitrogen atoms of two bpe ligand. Weak interactions such as hydrogen-bonding, π⋯π stacking interaction join the polymeric chain to generate three dimensional network structures. The framework is stable up to 232 °C and nitrogen adsorption measurement reveals the adsorption of 11.4 cc g−1 at P/P0∼0.95.

Metal–Thiobenzoato Complexes: Synthesis, Structure, and Processing as Carbon‐Supported Nanoparticles

Six new compounds of formula [M(TBn)2L] [TBn: thiobenzoato; M: PdII, ZnII, CdII; L: 2,2′‐bipyridine (bpy), 1,10‐phenanthroline (phen), 1,2‐di‐(4‐pyridil)‐ethylene (bpe), neocuproine (neo), adenine (ade)] are obtained by the reaction of M(CH3COO)2·2H2O with thiobenzoic acid and N‐heterocyclic ligands. The use of chelating ligands and adenine leads to monomeric compounds: [Pd(TBn)2(bpy)] (PdBPY), [Pd(TBn)2(phen)] (PdPHEN), [Zn(TBn)2(neo)] (ZnNEO), [Cd(TBn)2(neo)] (CdNEO), and [Cd(TBn)2(ade)(CH3OH)] (CdADE). In these compounds, the metal is bonded to the sulfur atoms of two TBn anions, while the remaining coordination positions are completed by the donor atoms of the ancillary ligands. The bridging capability of the bpe ligand gives rise to the polymeric [Cd(TBn)2(µ‐bpe)]n (CdBPE) compound. The presence of direct sulfur–metal bonds and carbon‐rich coligands enables these complexes to yield, by means of a dry thermolysis process, a set of metallic and metal–sulfide nanoparticles embedded into a carbonaceous support. The process to produce the latter materials consists of aerobic thermolysis using moderate temperatures (300–500 °C) and short exposure times (minute scale). Analysis of the XRD patterns and SEM/TEM images reveals that the carbonaceous matrix hosts well‐dispersed nanocrystallites. The influence of the metal(II) atom, ancillary ligand, and thermal treatment parameters on the crystalline phase, size, and purity of the resulting carbon‐supported nanoparticles is discussed.