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A series of Ln-sulfoterephthalate coordiantion polymers, namely, [Ln(2-stp)(4,4'-bbpi) (H2O)2]⋅H2O [Ln = Eu (1), Tb (2), Dy (3)] (2-H3stp = 2-sulfoterephthalate; 4,4'-bbpi = 4,4'-bisbiphenylimidazole), were prepared by hydrothermal method and characterizatied by EA, IR, TGA, and PXRD technologies. Single crystal X-ray diffraction analyses show that the three complexes are isostructral twodimensional network featuring helical chain structures. The fluorescence studies show that the emissions of the coordination polymers exhibit the characteristic peaks of lanthanide ions, which means they could be potential fluorescence materials. [ABSTRACT FROM AUTHOR]

Radical salts and charge-transfer complexes (CTCs) containing tetracyanoquinodimethane (TCNQ) display electrical conductivity, which has led to the development of many TCNQ derivatives with enhanced electron-accepting properties that are applicable toward organic electronics. To expand the family of TCNQ derivatives, we report the synthesis and structures of 11,11,12,12-tetracyano-2,6-diiodo-9,10-anthraquinodimethane (abbreviated as DITCAQ), C20H6I2N4, and its charge-transfer complexes with various electron donors, namely DITCAQ-anthracene (2/1), C20H6I2N4·0.5C14H10, (I), DITCAQ-pyrene (2/1), C20H6I2N4·0.5C16H10, (II), and DITCAQ-tetrathiafulvalene (2/1), C20H6I2N4·0.5C6H4S4, (III). The molecular structure of DITCAQ consists of a 2,6-diiodo-9,10-dihydroanthracene moiety with two malononitrile substituents. DITCAQ possesses a saddle shape, since the malononitrile groups bend significantly up out of the plane of the central ring and the two benzene rings bend down out of the same plane. π-π interactions between DITCAQ and the electron-donor molecules control the degree of charge transfer in cocrystals (I), (II), and (III), which is reflected in both the dihedral angles between the terminal benzene ring and the central ring on the DITCAQ motifs, and their corresponding IR spectra. [ABSTRACT FROM AUTHOR]

We report the single crystal structure and thermal properties of 1,2-bis(phenylethynyl)benzene (PEB), revealing that PEB forms a metastable liquid at rt, ca. 35 °C below its melting point. Accelerated nucleation of PEB from its supercooled state was induced with high reproducibility by a shock wave with ca. 15 ns duration and 1.2 GPa peak pressure. By conducting shock wave experiments with varying peak pressures, we observed a correlation between the frequency of accelerated nucleation and shock intensity. The generality of shock-induced nucleation for supercooled liquids was probed with other organic supercooled liquids bearing phenyl rings. However, accelerated nucleation after shock wave impact was only observed for PEB, possibly due to the low rotational energy barrier of the terminal phenyl rings. [ABSTRACT FROM AUTHOR]

Core–shell structure nanoparticles are attracting considerable attention because of their applications in drug delivery, catalysis carrier, and nanomedicine. In this study, SiO 2 @SiO 2 core–shell structure with tunable void and shell thickness was successfully prepared for the first time using SiO 2 -poly(buty acrylate) (PBA)-poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) (SiO 2 -PBA- b -PDMAEMA) as the template and tetraethoxysilane (TEOS) as the silica source. An amphiphilic copolymer PBA- b -PDMAEMA was first grafted onto the SiO 2 nanosphere surface through activators regenerated by electron transfer for atom transfer radical polymerization. TEOS was hydrolyzed along with the PDMAEMA chain through hydrogen bonding, and the core–shell structure of SiO 2 @SiO 2 was obtained through calcination to remove the copolymer. The gradient hydrophilicity of the PBA- b -PDMAEMA copolymer template facilitated the hydrolysis of TEOS molecules along the PDMAEMA to PBA segments, thereby tuning the voids between the SiO 2 core and SiO 2 shell, as well as the SiO 2 shell thickness. The voids were about 10–15 nm and the shell thicknesses were about 4–11 nm when adding different amounts of DMAEMA monomer. SiO 2 @SiO 2 core–shell structures with tunable void and shell thickness were employed as supports for the loading and release of doxorubicin hydrochloride (DOX) in PBS (pH 4.0). The samples demonstrated good loading capacity and controlled release rate of DOX. [ABSTRACT FROM AUTHOR]

Two novel lanthanide coordination polymers, {[Ln(stp)(bipy)(H2O)] ·(H2O)} n [Ln = Eu ( 1) and Dy ( 2)], were synthesized by hydrothermal reactions of 2-sulfoterephthalate (stp) and 4,4′-bipyridine (bipy) ligands with europium/dysprosium(III) salts. Structural analyses show that both complexes 1 and 2 are isomorphic and crystallize in the monoclinic crystal system with space group P21/ n. Complex 1 exhibits a two-dimensional grid-like structure from europium(III) ions bridged by the carboxyl and sulfonate groups of stp ligands. Notably, the stretching 4,4′-bipyridine ligands besides the 2D grid-like layers form π ···π interactions and interpenetrate into the empty voids of another adjacent layer into a twofold interpenetrated structure. Fluorescence analysis show that the emission of two complexes exhibit the characteristic peaks of lanthanide ions. [ABSTRACT FROM AUTHOR]

Abstract. Based on a mononuclear precursor [Mn(Hstp)2(4,4′-Hbpy)2] ( 1), a hetero-metallic complex, [Mn2Ni(stp)2(4,4′-bpy)(H2O)4] ( 2) [stp = 2-sulfoterephthalate, 4,4′-bpy = 4,4′-bpyridine] was synthesized by solvothermal reaction. Single-crystal X-ray diffraction analysis reveals that the MnII ion of the precursor 1 is hexacoordinate by four oxygen atoms from two Hstp2- anions and two nitrogen atoms from two protonated 4, 4′-Hbpy, and hydrogen bonding plays a significant role in constructing 3D supramolecular structure. While complex 2 features a self-weaving framework from 1D straight chains and 2D wavy networks with double helical chains. Magnetic behavior of complex 2 was analyzed in connection with its crystal structure, which exhibits the weak antiferromagnetic interactions between the MnII and NiII ions. [ABSTRACT FROM AUTHOR]

Abstract: Three new coordination polymers, [M1.5(stp)(bpe)(H2O)] (M=Mn(1), Cd(2), Zn(3)) have been prepared by hydro-/solvo-thermal reactions of 2-sulfoterephthalate (stp) and 1,2-bis(4-pyridyl)ethane (bpe) ligands with d-block Mn(II), Cd(II) and Zn(II) salts. Complexes 1 and 2 are isomorphic except for the difference of the metal ions, while complexes 1–3 are polymorphic because of the different coordination modes that stp ligand adopts. The left- and right-handed helixes construct 2D layer from metal ions and stp ligands for 1–3, and the anti-bpe ligands as the pillars complete 3D structure. All the three complexes exhibit a new (2,3,4)-connected network with the Schläfli symbol {8;122}4{82; 12; 142; 16}{8}2 based on the different structural motifs. The magnetic properties of 1 reveal that there exists weak antiferromagnetic coupling between the Mn(II) ions. And the solid-state photoluminescence of 2 and 3 can be attributed to the intraligand π–π* transition. [Copyright &y& Elsevier]

Heteroatom-doped organic π-conjugated molecules (OCMs) have become one type of emerging optoelectronic material with intriguing functionalities. Phosphorus (P)-doped OCMs are a special member of heteroatom-doped OCMs where rich P-chemistry is able to fine-tune their optoelectronic properties. Herein, we report a new series of nonplanar diazaphosphepine-based polycyclic aromatic heterocycles (DPP-PAHs). Efficient and mild double P–N cyclization allowed one to readily incorporate two P-centers in DPP-PAHs. With nonplanar diazaphosphepine rings, DPP-PAHs exhibit contorted structures in single crystal structures. The functionalization of double P-centers by H2O2 and S8 gave DPP-PAHs with P＝O and P＝S centers, respectively. Compared with the parent small molecule, the DPP-PAHs exhibit high photoluminescence quantum yields. Our experimental and theoretical studies further revealed that both P-environments and conjugated backbones have impacts on the photophysical properties of the DPP-PAHs. [ABSTRACT FROM AUTHOR]

Despite huge efforts have been devoted to investigating ultrathin layers of two-dimensional (2D) transition-metal dichalcogenides (TMDs), their realistic applications in electronics and optoelectronics are hindered by limited scalability and uniformity of 2D thin layers. In this work, a two-step synthesis method was adopted to produce wafer-scale molybdenum diselenide (MoSe2) nanosheets. Molybdenum oxide (MoO3) thin film was initially prepared via atomic layer deposition (ALD) and followed by a selenization process in chemical vapor deposition (CVD) tube furnace. MoSe2 nanosheets with desired thickness can be obtained by tuning ALD cycles in preparing MoO3 layers. The synthesized MoSe2 films exhibited excellent layer controllability, homogeneity and wafer-scale uniformity. Few-layer structure of our MoSe2 with a polycrystalline crystal structure was verified by means of Raman and transmission electron microscopy (TEM) measurements. Moreover, arrays of MoSe2-based photodetectors with different device dimension were fabricated and the photo-responses of the devices were studied. The device exhibited a fast photo-response time of 50 ms, a high on/off ratio of ~ 24 and a good photo-responsivity of 11.7 mA/W, and it is found that the effective illumination area was a critical factor for application. The work opens up an attractive approach to realize the application of wafer-scale 2D materials in integrated optoelectronic-systems. [ABSTRACT FROM AUTHOR]

Six Zn/Cd metal–organic frameworks (MOFs), {[Zn2(dppa)(bpy)2(H2O)]·H2O}n (1), {[Zn2(dppa)(phen)2(H2O)]·3H2O}n (2), [Cd(H2dppa)(bpy)]n (3), {[Cd2(dppa)(dye)]·H2O}n (4), {[Cd4(dppa)2(H2O)9]·H2O}n (5) and {[Cd2(dppa)(bpe)2(H2O)]·H2O}n (6) (H4dppa = 5-(3′4′-dicarboxylphenoxy)isophthalic acid, phen = 1,10-phenanthroline, bpy = 2,2′-bipyridine, dye = 2,2′-dipyridylamine, bpe = 1,2-bis(4-pyridy) ethane), were synthesized and structurally characterized by elemental analyses, plasma (ICP) spectrometry, IR spectroscopy, and single-crystal X-ray diffraction analyses. 1–3 are 1D ring chains. 4 shows a 2D bilayer network based on a tetranuclear cadmium cluster linked by (dppa)4− ligands. 5 displays a 2D bilayer network based on a trinuclear cadmium cluster, in which (dppa)4− ion shows two different coordination modes. In contrast to the above MOFs, 6 possesses a 3D network structure based on dinuclear cadmium units cross-linked by (dppa)4− and bpe ligands. For 1–6, weak hydrogen bonding and π⋯π stacking contacts link the discrete 1D chains or 2D networks to form high-dimensional supramolecular structures. Especially, in 1–6, (dppa)4− ligand displays seven different coordination modes and conformations, which may show natural synergy in the structural diversity of the resulting MOFs. The remarkable characteristic of these frameworks is that 2 demonstrates highly selective and sensitive bifunctional luminescent sensing towards acetone and Fe3+ ion. In addition, the thermal stabilities and luminescence properties of the MOFs were studied. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Two series of Pb substituted α-Bi 1-x Pb x Pd and β-Bi 2-x Pb x Pd were successfully synthesized by facile solid-state method. • Bi 1-x Pb x Pd (0 ≤ x ≤ 0.2) and Bi 2-x Pb x Pd (0 ≤ x ≤ 0.5) samples show bulk superconductivity and T c monotonically change as increases of Pb content. • One can see that the cell volume has also shown a monotonous decreasing change with higher Pb content for both alloys, which can be attributed to the slightly smaller atomic radius of Pb (1.75 Å) than Bi (1.82 Å). Abstract A series of Pb-doped Bi-based alloys, α-Bi 1-x Pb x Pd (0 ≤ x ≤ 0.5) and β-Bi 2-x Pb x Pd (0 ≤ x ≤ 0.6), were synthesized by facile solid-state reaction method. The powder X-ray diffraction confirmed that the crystal structure of samples remained the same after Pb-doping and the cell volume decreased with increasing Pb content. The influence of Pb-doping effect on superconductivity of BiPd and Bi 2 Pd alloys has been systematically examined by the magnetic susceptibility and resistivity measurements. Both alloy systems have shown bulk superconductivity and metallic conductivity in normal state. Furthermore, the superconducting onset temperature (T c) gradually decreased with higher Pb content for both systems. The T c dropped from 3.7 K for BiPd to 2.7 K for Bi 0.8 Pb 0.2 Pd, whereas the T c dropped from 5.3 K for Bi 2 Pd to 2.4 K for Bi 1.5 Pb 0.5 Pd. [ABSTRACT FROM AUTHOR]

abstract Two novel coordination polymers (CPs), [Cd 2 (cbta)(phen) 2 (H 2 O)] n (1), {[Zn 2 (cbta)(phen) 2 ] [Zn 2 (cbta) (phen) 2 (H 2 O)]·4H 2 O} n (2) (H 4 cbta = 1-(2-carboxylphenoxy)-2,3,5-benzene tricarboxylic acid; phen = 1,10-phenanthroline), were synthesized and characterized by elemental analyses, FT-IR spectra, single-crystal X-ray diffraction analyses. CP 1 shows a 2D network structure based on tetranuclear CdII clusters and (cbta)4- ligands, which are arranged in a [ABAB···] alternation to form a 3D supramolecular structures through π···π stacking interactions. Noticeably, CP 2 contains two kinds of independent units [Zn 2 (cbta)(phen) 2 ] (A) and [Zn 2 (cbta)(phen) 2 (H 2 O)]·4H 2 O (B) to form a 1D+1D structure. A shows 1D double chain based on Zn1, Zn2, which are recognized each other to generate a 2D supramolecular network (A) by hydrogen bonding interactions. While B are ring chains comprised of Zn3, Zn4, which are linked into 2D supramolecular network (B) through π···π stacking interactions. The peculiar structural feature is that the neighboring 2D networks are arranged in a [ABAB···] alternation to form a 3D supramolecular structure through hydrogen bonding interactions and C H···π and C H⋯O week interactions. Especially the (ctba)4- ligands in 1 – 2 adopt three different conformations and coordination modes. The thermal stabilities, XRD, UV, photoluminescence properties of CPs 1–2 were also studied. Remarkably, CPs 1–2 exhibit photocatalytic activities for degradation of dye (MB) under UV light irradiation and show good stabilities toward UV-light photocatalysis. Graphical abstract Two novel d10 metal CPs have been successfully synthesized and structurally characterized. 1 is a 2D network structure based on tetranuclear CdII clusters. 2 contains two kinds of independent units [Zn2(cbta)(phen)2] (A) and [Zn2(cbta) (phen)2(H2O)]·4H2O (B) to form an 1D+1D structure. The peculiar structural feature is that the neighboring A and B chains are arranged in a [ABAB···] alternation to form 3D supramolecular structure through hydrogen bonding interactions and π ... π stacking interactions. In addition, the thermal stability, photoluminescence and photocatalysis of 1–2 were also studied. Image 1 Highlights • Two Cd/Zn CPs with H 4 cbta and phen ligands. • 1 shows a 2D network based on tetranuclear CdII clusters and (cbta)4- ligand. • 2 contains two independent units (A) and (B) to form an 1D+1D structure. • The thermal stabilities and luminescence properties were also studied. • 1–2 exhibit photocatalytic activities for degradation of dye under UV light irradiation. [ABSTRACT FROM AUTHOR]

A novel pyridine-incorporated cyclo[6]aramide is designed and synthesised for recognition of urea and its derivatives. Analysis of its single crystal structure reveals the presence of introverted amide NH protons and amide carbonyl groups that are supposed to contribute to the subsequent accommodation of neutral urea-related guest molecules via multiple hydrogen bonding interactions. Thiourea is found to be superior to urea in binding to the receptor. Particularly interesting is the observation of two binding modes in complexing urea/thiourea (contact mode) and ethylurea/diethylurea (threading mode) as supported by both NMR experiments and computational simulations. The finding of the threading mode may open up new opportunities for the development of pesudorotaxanes and related mechanically interlocked structures. [ABSTRACT FROM AUTHOR]

The miscibility, crystalline structure and morphology, as well as, properties of Polyamide 6 (PA6)/polyvinylidene fluoride (PVDF) blends (with up to 50 wt% of PVDF) were studied. Small Angle X-ray Scattering study above the melting point of PVDF shows that the blends have very limited miscibility with approximately 5 wt% of PVDF inclusion in PA6 amorphous lamellar region. SAXS results also indicate a certain degree of PA6 inclusion into PVDF region though quantitative evaluation is unavailable with the limited blends studied in this work. The fine PVDF dispersion in the PA6 blends with up to 50 wt% of PVDF with an average size about 150 nm is supposed to be the result of the partial miscibility. The partial miscibility has great effects on the morphology and properties of the blends. Crystallization of both components are suppressed in the blends, especially on the PVDF component, which shows a significantly lowered crystallization temperature (up to 30 °C) during a cooling and a dramatic drop in crystallinity. Morphological studies together with Small Angle Light Scattering (SALS) show that spherulites, consisting of PA6 skeleton with dispersed PVDF domains (∼150 nm) engulfed among PA6 fibrils, are formed in the blends. The PA6 based spherulites become more defective with the increase in PVDF content, resulting in short/broken fibrils and undetectable PA6 spherulites for the blends with 30–50 wt% of PVDF at the temperature over the melting point of PVDF, say 185 °C. The blends show a significantly improved toughness compared with neat PA6, due to the partial miscibility which leads to the fine dispersion of PVDF domains in PA6 spherulites. [ABSTRACT FROM AUTHOR]

Two coordination polymers, {[Zn2(L)(bpy)] ·2H2O} n ( 1) and [Zn2(L)(bpe)] n ( 2) [H4L = terphenyl-2,2′,4,4′-tetracarboxylic acid, bpy = 4,4′-bipyridine, and bpe = 1,2-bis(4-pyridyl)ethane], were hydrothermally synthesized under similar conditions and characterized by elemental analysis, IR spectroscopy, TGA, and single-crystal X-ray diffraction analysis. Compound 1 has a 3D framework containing Zn-O-C-O-Zn 1D chains. Compound 2 exhibits a 3D framework, which features tubular channels. The channels are occupied by bpe molecules. The differences in the structures demonstrate that the auxiliary dipyridyl-containing ligand has a significant effect on the construction of the final framework. Additionally, the fluorescent properties of the two compounds were also studied in the solid state at room temperature. [ABSTRACT FROM AUTHOR]

In this article, [Ag8(btc)2(2,2′-bpy)2] n (1) and [Ag4(btc)(phen)2] n (2) (H4btc = biphenyl-2,2′,4,4′-tetracarboxylic acid, 2,2′-bpy = 2,2′-bipyridine, phen = 1,10-phenanthroline) have been synthesized under hydrothermal conditions and characterized by elemental analysis, IR spectra, thermogravimetric analyses, and single-crystal X-ray diffraction. Complex 1 shows a 3-D framework containing a 2-D bilayer network constructed from (btc)4− with Ag (I), whereas 2 features a 2-D supramolecular bilayer network. The differences of the two complexes demonstrate that nitrogen-containing chelating ligands have a significant effect on the formation and structure of the resulting complexes. Electrochemistry properties of 1 were also studied. [ABSTRACT FROM PUBLISHER]

Two new coordination polymers, [Zn(H2btc)(4,4'-bpy)2]n (1) and {[Cd(H2btc) (terpy)] · H2O}n (2) (H4btc = biphenyl-2,2',4,4'-tetracarboxylic acid, 4,4'-bpy = 4,4'-bipyridine, terpy = terpyridine), have been synthesized under hydrothermal conditions and characterized by elemental analysis, IR spectra, and single-crystal X-ray diffraction. Complexes 1 and 2 are 1-D chains linked through partially deprotonated H4btc. The adjacent 1-D chains of 1 are further formed into 2-D supramolecular architecture through inter-chain N-H···O hydrogen bonds. In contrast, due to a different auxiliary ligand, the 1-D chains of 2 are further extended into 3-D supramolecular framework through inter-chain O-H···O hydrogen bonds. Thermal stabilities and luminescence of 1 and 2 were also studied. [ABSTRACT FROM AUTHOR]

Both the ≡Fe(III) reduction and the catalyst stability are the main obstacles limiting the application of such Fe-doped Fenton-like catalysts in endocrine disruptors removal. Herein, oxygen was introduced to the Fe-g-C 3 N 4 to fabricate a newly Fe–O-doped catalyst FeCA-g-C 3 N 4. The pseudo-first-order rate constant for bisphenol A (BPA) degradation in FeCA-g-C 3 N 4 system is 2.6 times higher than that in the traditional Fe-doped g-C 3 N 4 (FeCl 3 -g-C 3 N 4) system. And the formation of Fe–O bond can strengthen the stability of the catalyst. After operating 400 h, the π conjugate plane in the FeCl 3 -g-C 3 N 4 was completely destroyed, and the degradation of BPA was less than 3%. However, the crystal structure of FeCA-g-C 3 N 4 was relatively intact, and the degradation of BPA was still above 90%. According to the XPS and EXAFS spectra, the improvement of the FeCA-g-C 3 N 4 stability was attribute to the shorter lengthen of the Fe–O bond (1.47 Å). Besides, the introduction of electron-rich oxygen center can also effectively promote the reduction of ≡Fe(III) and directly activated H 2 O 2. Additionally, the electron-rich oxygen will also alleviate the shielding effect of halogen ions on the Fe sites, and the low concentration (<0.01 mM) of halide ions could even promote H 2 O 2 activation by 12.2%–24.5%. In conclusion, this study provides new insights to strengthen catalyst stability and accelerate electron transfer in the Fenton-like process, promoting its application in the actual wastewater purification. [Display omitted] • Fe–O-doped g-C 3 N 4 catalyst was fabricated by using ferric citrate as iron source. • Oxygen center can directly activate H 2 O 2 through single electron transfer. • Formation of Fe–O bond greatly improves the stability of the catalyst. • Oxygen center can improve the anti-interference ability of the catalyst. [ABSTRACT FROM AUTHOR]

Maleic anhydride (MAH) grafting to different polyolefins with similar grafting degree can have different effects on crystallization, crystal structure, and mechanical and thermal properties. The grafting leads to a smaller crystal size, less ordered lamellar structure, and a shorter long period for HDPE, LLDPE, and PP. The grafting makes PP lamellar packing less ordered the most and almost no effect to LLDPE. The grafting does not have that much impact on the crystallization ability of the HDPE, LLDPE, and HDPE/PP blend, but appreciably reduces the crystalline ability of PP-g-MAH, due to a dramatical drop in its molecular weight during the grafting process. As a result, the grafting makes PP a very brittle material with a lowered average melting point than the corresponding neat PP, but the grafting has almost no effect on elongation at break for LLDPE and some effect on HDPE (decreased by one-third). However, the PP degradation due to MAH grafting can be avoided in the presence of PE component, i.e., making the grafting of PP and PE at the same time with HDPE/PP blend. The grafted HDPE/PP blend shows a significantly improved compatibility, which leads to overall appreciably better mechanical properties than the neat HDPE/PP blend. [ABSTRACT FROM AUTHOR]