Search

Highly site- and enantio-selective additions of polyfunctional nucleophiles to imines or carbonyls were achieved via a carboxyl-assisted strategy, affording δ-substituted-β-keto esters and β-substituted ketones with good yield and enantioselectivity.

A stable 3-D metal–organic framework (MOF), [Cd(H2DTPA)(1.2-mbix)]n (1), has been constructed with aromatic 2,3-dihydroxy terephthalic acid (H4DTPA) and cadmium salt under solvothermal conditions. ...

One novel three-dimensional (3-D) copper(I)-thioarsenate(III) [Ni(en)3]Cu4As4S9 (1, en = ethylenediamine) has been solvothermally prepared with the utilization of the in situ formation of [Ni(en)3]2+ complex as structure-directing agent (SDA). 1 contains cubane-like [Cu8S12]16- clusters and rare tetrameric [As4S9]6- units, which are interconnected to generate the first example of a 3-D anionic framework [Cu4As4S9]n2n-, topologically identical to pyrite, and having large channels filled by [Ni(en)3]2+ complex cations. 1 is a potential wide-band-gap semiconductor with an energy gap of 1.91 eV that exhibits selectively photocatalytic degradation of methylene blue under visible-light irradiation. The density functional theory calculation, photocurrent response, and magnetic properties of 1 were also investigated.

A multifunctional metal-organic framework, (Hdmbpy)[Dy(H

Two homochiral EuIII and SmIII tris(β-diketonate) enantiomeric pairs, based on fluorinated β-diketone (Hbtfa) and enantiopure asymmetric N,N'-donor ligands (LR and LS), Λ-Eu(btfa)3LR (R-1-Eu)/Δ-Eu(btfa)3LS (S-1-Eu) and Λ-Sm(btfa)3LR (R-2-Sm)/Δ-Sm(btfa)3LS (S-2-Sm) (btfa- = 4,4,4-trifluoro-1-phenyl-1,3-butanedionate and LR/LS = (-)/(+)-4,5-pineno-2,2'-bipyridine) were synthesized. The electronic circular dichroism (ECD) spectra confirmed their enantiomeric nature. R-1-Eu/S-1-Eu and R-2-Sm/S-2-Sm exhibit intense characteristic emissions of EuIII (red) and SmIII (orange-red) ions both in the solid state and in DCM with long lifetimes and high luminescence quantum yields. For example, the overall quantum yields reach up to 61% and 53% along with very high sensitization efficiency values of 82 and 79 for R-1-Eu in the solid state and in DCM, respectively. Notably, the corresponding values are determined to be 6.5% (solid state) and 3.1% (DCM) for R-2-Sm, which are among the highest quantum yields for rare SmIII tris(β-diketonate) luminescent complexes reported to date. Furthermore, R-1-Eu and R-2-Sm show a strong triboluminescence (TL) phenomenon visible with the naked eye in daylight. Moreover, R-1-Eu/S-1-Eu and R-2-Sm/S-2-Sm show circularly polarized luminescence (CPL) properties. Particularly, the luminescence dissymmetry factors (glum) for R-2-Sm/S-2-Sm are larger than those for R-1-Eu/S-1-Eu despite the fact that SmIII complexes usually show poorer emission than EuIII homologues, which is very rare in the reported EuIII and SmIII CPL-active complexes.

By the solvothermal assembly of Gd3+ and 5,5'-(anthracene-9,10-diyl)diisophthalic acid (H4adip), an anthracene-based lanthanide coordination polymer (CP), [Gd2(adip)(H2adip)(NMP)2]·DMF·3H2O (1; NMP = N-methylpyrrolidone; DMF = N,N-dimethylformamide), has been prepared. It possesses a 3D framework and a strong ligand-based blue emission. 1 could be applied as a multifunctional chemical sensor for UO22+, PO43-, and 2-thiazolidinethione-4-carboxylic acid (TTCA) with excellent selectivity, sensitivity, and anti-interference. In the 0-20 μM concentration range of UO22+, the quenching constant (KSV) is 4.05 × 104 M-1 with a detection limit of 1.42 μM. Fluorescence enhancement was observed when PO43- was added to the 1-H2O suspension. The slope of the linear relationship between the PO43- concentration in the 0-35 μM concentration range and I/I0 is 3.70 × 104 M-1 with a detection limit of 1.55 μM. When the TTCA concentration is lower than 20 μM, the fluorescence quenching constant KSV is 1.77 × 104 M-1 with a detection limit of 3.25 μM, which approaches the values reported of the best CP-based sensing materials for TTCA up to now. Moreover, the fluorescence quenching or enhancement mechanism was also investigated.

A Yb(OTf)

A phosphoric acid catalyzed atroposelective Friedländer reaction was developed in which acetylacetone and a variety of 2′-substituted 2-aminobenzophenones were successfully employed to give optically active biaryl quinolines in good yields and with high enantioselectivities.

An efficient, practical, highly selective and environmentally benign method is reported for the synthesis of aryl thioethers via the coupling of thiols with aryl boronic acids in the presence of NaOH and a catalytic amount of CuSO4 at 130 °C using water as a green solvent. The products were obtained in moderate to excellent yields; more importantly, the use of toxic ligands and solvents was avoided. A broad range of aryl boronic acids and scalable processes make this methodology valuable and versatile for the synthesis of a broad range of aryl sulfides.

One novel three-dimensional (3-D) copper(I)-thioarsenate(III) [Ni(en)

We described a Ni-bidentate oxazoline catalyzed highly enantio- and diastereoselective decarboxylative aldol reaction of 2-oxotetrahydrofuran-3-carboxylic acid/2-oxochromane-3-carboxylic acid derivatives with different kinds of carbonyls. Under optimal reaction conditions, α-substituted β-hydroxy butyrolactones and dihydrocoumarins with an all-carbon quaternary stereocenter have been generated with high levels of functional-group compatibility. Furthermore, proficient transformations of products were also described, in which an aliphatic tertiary alcohol and a multi-substituted 1,4-diol were smoothly constructed through hydrogenation and ring-opening reaction, respectively.

The exploration of catalytic potential of natural amino acid salt in activation of 1,3-dicarbonyls was carried out, in which maleimides and 2-(2-oxoindolin-3-ylidene)malononitriles were found to be good electrophiles and afforded the desired products with excellent yield and moderate optical purity. Control experiments showed that the secondary amino group of barium (S)-prolinate is critical to the catalytic activity as well as enantiocontrol, thus revealed an enamine activation mechanism is possible in the present methodology.

Reaction of the phenanthridine ligand (phend) with ZnBr2 in DMSO/MeOH or MeOH yielded the complexes ZnBr2(phend)(DMSO) (1) and ZnBr2(phend)2 (2) respectively. These complexes were characterized by single crystal X-ray diffraction, IR spectroscopy and elemental analyses. Sonochemical preparation of complexes 1 and 2 in methanolic solution generated porous texture (pt) crystals 1 pt and 2 pt. Comparison of the X-ray powder diffraction data confirmed identical crystal structures for 1 and 1 pt as well as 2 and 2 pt. The porous texture (the mixture of nano-porous and micro-pores) morphologies of the sonochemical products were confirmed by scanning electron microscopy. Reaction conditions, such as solvent and the concentration of the initial reagents, played important roles in the size and growth process of the crystalline products.

Five new Zn(II) coordination polymers, {[Zn2(HBPO)2(phen)2(H2O)2]·H2O}n (1), [Zn2(BPO)(H2BPO)(phen)4]·2(H2BPO)·4H2O (2), {[Zn(HBPO)(4,4′-bipy)0.5]·H2O}n (3), [Zn(HBPO)(dpe)0.5]n (4) and {[Zn2(HBPO)2(dpp)]·H2O}n (5), constructed from mixed ligand; bis(4-carboxylphenyl)phosphinic acid (H3BPO) and N-donor pyridine ligands (phen, 4,4′-bipy, dpe and dpp), have been synthesized and characterized by single crystal X-ray diffraction, IR spectroscopy and elemental analyses. Intermolecular hydrogen bonds, π- π interaction and other intermolecular interaction are effective in stabilization of the crystal structure of these supramolecular complexes. The thermal stability and luminescence properties of compounds 1–5 in the solid state were studied too.

Five new cadmium(II) coordination polymers [Cd(HPBO)(2,2′-bipy)]n (C1), (H3PBO = 4,4′-(hydroxyphosphoryl)dibenzoic acid, 2,2′-bipy = 2,2′-bipyridine), [Cd(HPBO)(phen)]n (C2), (phen = 1,10-phenanthroline), [Cd(HPBO)(4,4′-bipy)0.5]n (C3) (4,4′-bipy = 4,4′-bipyridine), [Cd(HPBO)(dpe)0.5]n (C4), (dpe = 1,2-di(pyridin-4-yl)ethene), [Cd2(HPBO)2(dpp)]n (C5), (dpp = 1,3-di(pyridin-4-yl)propane) were synthesized and characterized by elemental analysis, IR spectroscopy and single crystal X-ray diffraction. The thermal stabilities and luminescence properties of compounds C1–C5 were investigated. The N-donor ligands influence the coordination mods of the Cd(II) centers and dimensionality of the structures and H3PBO accept either bridging and chelating modes. C2 exhibits a 3-connected 2D network of a hcb topology with a point symbol of (63). C3 and C4 show the same unprecedented (4, 10)-connected 3D network with a point symbol of (412·511·618·73·8)(46)2. C5 presents a (4, 10)-connected 3D network of a deh1 topology with a point symbol of (3·45)2(34·412·510·614·73·82).

Two homochiral EuIII and SmIII tris(β-diketonate) enantiomeric pairs, based on fluorinated β-diketone (Hbtfa) and enantiopure asymmetric N,N'-donor ligands (LR and LS), Λ-Eu(btfa)3LR (R-1-Eu)/Δ-Eu(btfa)3LS (S-1-Eu) and Λ-Sm(btfa)3LR (R-2-Sm)/Δ-Sm(btfa)3LS (S-2-Sm) (btfa- = 4,4,4-trifluoro-1-phenyl-1,3-butanedionate and LR/LS = (-)/(+)-4,5-pineno-2,2'-bipyridine) were synthesized. The electronic circular dichroism (ECD) spectra confirmed their enantiomeric nature. R-1-Eu/S-1-Eu and R-2-Sm/S-2-Sm exhibit intense characteristic emissions of EuIII (red) and SmIII (orange-red) ions both in the solid state and in DCM with long lifetimes and high luminescence quantum yields. For example, the overall quantum yields reach up to 61% and 53% along with very high sensitization efficiency values of 82 and 79 for R-1-Eu in the solid state and in DCM, respectively. Notably, the corresponding values are determined to be 6.5% (solid state) and 3.1% (DCM) for R-2-Sm, which are among the highest quantum yields for rare SmIII tris(β-diketonate) luminescent complexes reported to date. Furthermore, R-1-Eu and R-2-Sm show a strong triboluminescence (TL) phenomenon visible with the naked eye in daylight. Moreover, R-1-Eu/S-1-Eu and R-2-Sm/S-2-Sm show circularly polarized luminescence (CPL) properties. Particularly, the luminescence dissymmetry factors (glum) for R-2-Sm/S-2-Sm are larger than those for R-1-Eu/S-1-Eu despite the fact that SmIII complexes usually show poorer emission than EuIII homologues, which is very rare in the reported EuIII and SmIII CPL-active complexes.

In this work, two new enantiopure bis-monodentate N-donor chiral ligands, namely (−)/(+)-2-(4′-pyridyl)-4,5-pinene-pyridine (LR/LS), have been designed and synthesized. Using LR and LS as bridging ligands to react with AgClO4, a pair of novel 2D chiral Ag(I) enantiomers formulated as [Ag2(LR)2(ClO4)2]n (R-1) and [Ag2(LS)2(ClO4)2]n (S-1) were isolated and characterized. In R-1 and S-1, each Ag(I) ion is bonded by two N atoms from two different chiral LR or LS ligands, leading to the formation of 1D right- or left-handed –L–Ag(I)–L– helical chains. Moreover, two adjacent helical chains are further doubly linked by two monodentate ClO4− anions through weak Ag–O contacts to form 2D network structures, in which dual chiral elements, i.e., center chirality and helical chirality coexist. Interestingly, each free ligand LR/LS and R-1/S-1 enantiomers show very different ECD spectra in the solid state and in solution, which are correlated to the intermolecular interactions and molecular structures in each state, respectively. Notably, as a representative, R-1 exhibits intense room temperature photoluminescence both in the solid state and in solution with different emission features and mechanisms, while it also shows more intense emission than that of free ligand LR. In particular, R-1 and S-1 represent the first examples of 2D Ag(I) chiral coordination polymers (CCPs) supported by ClO4− anions, possessing dual chiral elements.

A new 3-D cuprous thiogermanate [H4teta]5[Cu40Ge15S60]·2.5(teta) (1, teta = triethylenetetramine) has been solvothermally synthesized and structurally characterized. The crystal structure of 1 is built up from a rare 3-D [Cu–S–Cu]n network and entrapped [GeS4] tetrahedra. This 3-D [Cu–S–Cu]n network is constructed by the linkages of icosahedral [Cu8S12] clusters and [Cu8S16] rings. 1 represents the only example of 3-D cuprous thiogermanate based on 3-D inorganic [Cu–S–Cu]n network. The absorption edge of 1 is 2.45 eV, exhibiting properties of the semiconductor. 1 exhibits photocatalytic activity for degradation of methylene blue (MB) under visible light.

A Ni-oxazoline complex-catalyzed asymmetric decarboxylative aldol reaction between malonic acid half-oxyesters and various carbonyls with carboxylate assistance was developed, affording structurally diverse β-hydroxy esters with good yields and enantioselectivities under mild conditions. Importantly, the broad substrate scope of this methodology enabled rapid accesses to several natural products and their analogues as exemplified by phenylpropanoid, phaitanthrin B, and phthalide.

Two Cd(II) coordination polymers constructed from tris(p-carboxylphenyl)phosphine oxide (H3TPO), [Cd(HTPO)(1,4-bix)·3H2O]n (1) and [Cd2(HTPO)(HBPO)(H2O)2]n (2) (1,4-bix = 1,4-bis(imidazol-1-ylmethy...

本文制备了三种同构镧系金属有机框架材料(Me2NH2)[Ln2L2(NO3)2(μ3-OH)(H2O)]·2H2O·2DMA, (Ln = Eu( 1 ), Gd( 2 ), Tb( 3 ), H2L = 9-甲基-9-羟基-2,7-芴二羧酸, DMA = 二甲基乙酰胺). 研究结果显示它们具有三维阴离子型框架结构, 该结构可简化为含有单一的8连接型节点的体心立方(bcu)型拓扑结构. 化合物 1 表现出基于配体的荧光发射峰以及铕离子的特征荧光发射峰. 荧光实验表明在DMF溶液中Al3+会明显增强配体的荧光强度, 而对Eu3+的荧光强度影响却很小, 这使得 1 成为了优秀的比率式发光Al3+传感器. 在Al3+浓度处于 0.02–0.1 mmol L−1 范围内时, 配体与Eu3+荧光强度的比值与Al3+浓度成正比(斜率为 18502 mol−1 L). 本文证实了配体9位的羟基与Al3+之间的相互作用是引起配体荧光增强的主要原因.

A novel 3-D cuprous iodide polymer [CuI3I(μ6-L)]n with a Cu/I ratio as high as 3 (1, H2L = 1,3-bis(2H-tetrazol-5-yl)benzene) has been hydrothermally synthesized. The 3-D framework of 1 is constructed by the linkages of rare 1-D cationic aggregates [CuI3I2+]n and anionic bi-tetrazolate bridges. 1 shows unusually thermochromic luminescent and photocatalytic properties, and its density functional theory calculation has also been studied.

Five Ag(I) coordination complexes, namely, [Ag 6 (2-stp) 2 (3-methyl-2-apy) 3 ·H 2 O] n ( 1 ), [Ag 3 (2-stp)(4-methyl-2-apy) 3 ] n ( 2 ), [Na 2 Ag 18 (2-stp) 4 (2-Hstp) 4 (5-methyl-2-apy) 16 (H 2 O) 4 ·11H 2 O] n ( 3 ), Ag 3 (2-stp)(6-methy-2-apy) 4 ·H 2 O ( 4 ), and [Ag 6 (2-stp) 2 (6-methyl-2-apy) 8 (H 2 O) 2 ·H 2 O] n ( 5 ) (2-NaH 2 stp = 2-sulfoterephthalic acid monosodium salt, 3-methyl-2-apy = 3-methyl-2-aminopyridine, 4-methyl-2-apy = 4-methyl-2-aminopyridine, 5-methyl-2-apy = 5-methyl-2-aminopyridine, 6-methyl-2-apy = 6-methyl-2-aminopyridine), have been synthesized and structurally characterized. Complexes 1 and 2 show two-dimensional network. In complex 3, the adjacent Ag 10 units are bridged by 5-methyl-2-apy ligands to form a 2D infinite undulated sheet. Adjacent 2D sheets are linked by coordinative bonds between carboxylic oxygen atoms and Na(I) ions to form a 3D coordination polymer. Complex 4 is a 0-D discrete trinuclear molecule, and the self-complementary the O H⋯O and N H⋯O hydrogen bonds incorporating hydrogen bond motifs extend these molecules into a 2D supramolecular framework. Compound 5 exhibits 1D-chain structure. However, complex 5 shows 3D supramolecular structure results from the linkage of neighboring layers through a rich hydrogen-bonding between uncoordinated sulfonates, amino groups and coordinated carboxylates. The thermogravimetric analyses and photoluminescence of the complexes were also investigated.

Three Ag(I) coordination complexes, namely [Ag3(2-stp)(2-apy)2·3H2O]n (1), [Ag3(2-stp)(2-apy)2]n (2) and [Ag3(2-stp)(3-apy)(H2O)]n (3) (2-NaH2stp = 2-sulfoterephthalic acid monosodium salt, 2-apy = 2-aminopyridine and 3-apy = 3-aminopyridine), have been synthesized and structurally characterized. They all show two-dimensional network structures. In complex 1, the Ag3 units are linked by stp ligands to form a 1D chain. Consequently, the 2-apy ligands link the adjacent 1D chain into 2D polymeric sheets. In 2, Ag1 and Ag2 atoms are bridged by stp ligands to form a 2D infinite sheet. In 3, the stp anion adopts a μ7-(η1,η2):(η1,η1,η0):(η1,η1) coordination mode to Ag3 units to 2D layer sheet and the network is consolidated by 3-apy ligands. The thermogravimetric analyses and photoluminescence of the complexes were also investigated.

Under the identical reaction conditions, two new TbIII and SmIII-hydroxo clusters with different nuclearity have been prepared and characterized by X-ray crystallography, spectroscopic methods and magnetic measurements. Solid-state structure analyses reveal that the TbIII cluster shows a pentanuclear square pyramidal shape of the composition [Tb5(μ3-OH)4(μ4-OH)(dbm)10]·2H2O (1, dbm– = dibenzoylmethanate) with the dbm ligands presenting two types of coordination modes [η2-and (μ-O)-η2-]. The SmIII species presents a tetranuclear parallelogram structure formulated as [Sm4(μ3-OH)2(dbm)10]·12H2O (2), and three types of coordination modes [η2-, (μ-O)-η2- and (μ-O)2-η2-] for dbm ligands are observed. The measurements of magnetic properties indicate that the direct-current (dc) magnetic behaviors of two clusters mainly result from the thermal depopulation of the Stark sublevels of the TbIII and SmIII ions, respectively. Meanwhile, alternating current (ac) magnetic susceptibility of 1 is also assessed. Investigations on luminescence properties show that 2 displays characteristic emission of the SmIII ion in visible range, while 1 does not exhibit any detectable emission. The interpretations of different emission behaviors for 1 and 2 are also presented in detail.

A series of lanthanides adipates [Ln 2(ad)3(H2O)4] [Ln = Y3+ (1), Ho3+ (2), Er3+ (3), Tm3+ (4); ad = adipate] have been hydrothermally synthesized and structurally characterized by elemental analysis, X-ray diffraction, thermogravimetric analysis, UV/Vis and IR spectroscopy. Compounds 1–4 are isostructural and exhibit 2-D polymeric layers constructed by Ln 3+ ions bridged via the carboxylate groups of adipate ligands in two binding modes. The magnetic properties of both 2 and 4 are investigated and their thermal behaviours are also discussed. The Ln 3+ ions (Ln = Y 3+ , Ho 3+ , Er 3+ , Tm 3+ ) bridged by the carboxylate groups of adipate ligands form 2-D polymeric layers.

Seven novel coordination polymers based on 2,2′-phosphinico-dibenzoic acid (H3L), namely, {[Zn3L2(H2O)4]·2H2O}n (1), [Zn3L2(4,4′-bipy)2]n (2), [Zn(HL)(2,2′-bipy)(H2O)]n (3), {[Cd9L6(H2O)8]·4H2O}n (4), [Cd8L4(OH)2(OAc)2(4,4′-bipy)]n (5), [Mn3L2(4,4′-bipy)(EtOH)(H2O)2]n (6), and [Mn(HL)(2,2′-bipy)(H2O)]n (7), were synthesized under hydro(solvo)thermal conditions. These compounds crystallize in the triclinic P1 space group for 1, 4, 5, and 6, the monoclinic space group C2/c for 2, and the monoclinic P21/c space group for 3 and 7. The L3– ligand displays versatile binding modes in 1–7. Compound 1 is a one-dimensional (1-D) chain coordination polymer with a three-dimensional (3-D) supramolecular framework. Compound 2 is a 3-D porous metal–organic framework (MOF) with two different 4,4′-bipyridine linkers. Compounds 3 and 7 show 1-D zigzag chain structures. Compound 4 exhibits a sophisticated 3-D MOF constructed from two types of Cd8 clusters and one Cd2 dimer, which is the first example exhibiting the coexist...

High-nuclearity metal clusters have received considerable attention not only because of their diverse architectures and topologies, but also because of their potential applications as functional materials in many fields. To explore new types of clusters and their potential applications, a new nickel(II) cluster-based mixed-cation coordination polymer, namely poly[hexakis[μ4-(2-carboxylatophenyl)sulfanido]di-μ3-chlorido-tri-μ2-hydroxido-octanickel(II)sodium(I)], [Ni8NaCl2(OH)3(C7H4O2S)6] n , 1, was synthesized using nickel chloride hexahydrate and mercaptobenzoic acid (H2mba) as starting reactants under hydrothermal conditions. The material was characterized by single-crystal X-ray diffraction (SCXRD), Fourier transform IR spectroscopy, thermogravimetric analysis, powder X-ray diffraction and X-ray photoelectron spectroscopy analysis. SCXRD shows that 1 consists of a hexanuclear nickel(II) [Ni6] cluster, dinuclear NiII nodes and a mononuclear NaI node, resulting in the formation of a complex covalent three-dimensional network. In addition, a tightly packed NiO/C&S nanocomposite is fabricated by sintering the coordination precursor at 400 °C. The uniform nanocomposite consists of NiO nanoparticles, incompletely carbonized carbon and incompletely vulcanized sulfur. When used as a supercapacitor electrode, the synthesized composite shows an extra-long cycling stability (>5000 cycles) during the charge/discharge process.

Considering the biological properties of the compounds containing quinoxaline and indandione skeleton, a new thiolate salt was synthesized via the reaction between ninhydrin and phenacyl thiocyanate in the presence of triethylamine and in continuous, from the reaction of this thiolate with methyl iodide and o-phenylenediamine in absolute ethanol, quinoxaline containing indandione substituent was obtained.

Single-material electrodes do not satisfy the demands of high-performance supercapacitors. Thus, to exploit the advantages of both oxides and carbon-based materials, a tightly packed Co3O4/C&S nanocomposite was fabricated by sintering a tightly packed cobalt(III) cluster-based coordination precursor at 400 ​°C. The coordination precursor, composites, and basic components were characterized, and the uniform nanocomposite was found to be composed of Co3O4 nanoparticles, incompletely carbonized C, and incompletely vulcanized S. When used as a supercapacitor electrode, the synthesized composite exhibited an exceptional electrochemical performance. More specifically, as the current density was increased from 0.5 to 10 Ag−1, 85.3% of the specific capacitance was retained. Moreover, >99.7% of the original specific capacitance was maintained after cycling for 20,000 cycles. This outstanding electrochemical performance was attributed to the highly stable electrode structure. These results indicate that a supercapacitor with electrodes composed of the as-prepared Co3O4/C&S composite show potential for use in commercial applications.

Using a chiral bis-bidentate isomer (–)-2,5-bis(4,5-pinene-2-pyridyl)pyrazine (LR) as bridging ligand to react with AgNO3 under solvothermal conditions, a chiral silver(I) complex formulated as [Ag(LR)·NO3]n (1) was obtained. Single crystal X-ray analysis revealed that 1 crystallizes in the non-centrosymmetric space group C2 with an infinite one-dimensional (1D) zigzag chain structure which is further linked together by C–H⋯π interactions to form a three-dimensional (3D) supramolecular framework. Each four-coordination Ag(I) atom is ligated by four N atoms from two LR ligands forming a distorted tetrahedral geometry. Circular dichroic (CD) spectrum confirmed its chiroptical activity. The measurements of second harmonic generation (SHG) and ferroelectric behavior showed that 1 displays nonlinear optical (NLO) activity and ferroelectricity. Furthermore, the investigation on luminescence property showed that 1 exhibits ligand center emission. All these indicate that 1 presents potential molecular-based multifunctional materials.

A series of donor–π–acceptor indene-1,3-dionemethylene-1,4-dihydropyridine (IDM-DHP) derivatives with different alkyl chain lengths on the DHP ring were synthesized to investigate the effect of N-alkyl chains on their fluorescence properties in the aggregated state. These compounds with highly distorted conformations show obvious aggregation-induced emission enhancement phenomena in a THF/water mixture because of the restriction of intramolecular rotation in the aggregated state, as confirmed by solution thickening experiments. The as-synthesized IDM-DHP solids emit strong yellow fluorescence and the general trend of their emission wavelengths decreases with the increase of the N-alkyl chain length. It is found that these compounds exhibit outstanding reversible mechanofluorochromic (MFC) properties, and N-alkyl chains play a functional role in tuning their MFC behaviours, that is, the longer alkyl-containing IDM-DHP solids show larger MFC spectral redshifts, which should be ascribed to the weaker CH/π hydrogen bonds in the molecules and as a result looser molecular stacking, as revealed by the single crystal X-ray diffraction analysis. Additionally, the fluorescence emission of the ground samples of these compounds can recover by annealing or solvent fuming. X-ray diffraction experiments reveal that the transformation between crystalline and amorphous states under various external stimuli should be responsible for the MFC properties. This work demonstrates that a simple alkyl chain change in the skeleton of some organic fluorophores can be used to tune their fluorescence properties in the aggregated state, which provides good design ideas for the development of novel IDM-DHP derivatives with MFC properties.

Two tetranuclear Lanthanide-hydroxo cubane clusters of composition [Ln4(μ3-OH)4{(μ-O)-η2-acac}4(η2-acac)4]·C7H8 (Ln = Er 1 and Yb 2, acac = acetylacetonate) have been prepared and characterized by elemental analyses, FTIR spectroscopy and X-ray crystallography. Single crystal X-ray analyses of 1 and 2 revealed that they are isostructural with the Ln4(μ3-OH)48+ cluster core showing cubane-like geometry. Each cluster consists of four lanthanide atoms, four μ3-O atoms, and eight acac ligands making up the peripheral part of the cluster. Two types of the coordination modes [η2- and (μ-O)-η2-] of the acac ligands in 1 and 2 are observed. Investigations on the magnetic properties of 1 and 2 indicate that both complexes do not exhibit frequency-dependent in-phase (χ′) and out-of-phase (χ′′) signals in the alternating current (ac) magnetic susceptibilities of 1 and 2. In particular, unlike most documented lanthanide β-diketonate mono- or multinuclear complexes exhibiting near-infrared (NIR) emission property, 1 and 2 do not show any detectable NIR emission at any temperature range and the reason of nonluminescence for 1 and 2 is further elucidated in this work.

Herein, we prepare two terpyridine-containing Pd(II) complexes, [PdClL1]∙solvent (A1) and [PdClL2]∙2H2O (A2) (L1 = 4’-(4-carboxyl-phenyl)-2,2’:6′,2″-terpyridine, L2 = 2,6-bis(2-pyrazinyl)-4-(4-carboxyl-phenyl)pyridine), from 4’-(4-cyanophenyl)-2,2’:6′,2″-terpyridine(L1a)/2,6-bis(2-pyrazinyl)-4-(4-cyanophenyl)pyridine (L2a) and Pd(II) acetate and characterise them by several instrumental techniques. A1 and A2 are shown to be good catalysts for the coupling of 2-iodobiphenyl with iodobenzenes to afford triphenylenes, which is known to involve dual C–H bond activation and double C–C bond formation. The obtained data suggest that the mechanism of A1-and A2-mediated coupling may be similar to the reference Pd catalysts, A1 and A2 are also suitable catalysts for this cyclization process. Study on this kind of complexes is of importance to the development of novel Pd-based catalysts and triphenylene synthesis techniques.

A chiral phosphoric acid promoted enantioselective NMR analysis of atropisomeric quinazolinones was described, in which a variety of racemic arylquinazolinones such as afloqualone and IC-87114 were well recognized with up to 0. 21 ppm ΔΔδ value. With this method, the optical purities of different non-racemic substrates can be fast evaluated with high accuracy.

A series of dicyanomethylene-1,4-dihydropyridine (DCMP) derivatives with aggregation-induced emission (AIE) were designed and synthesized. These target compounds emit low fluorescence in THF solutions because of the free rotation of the phenyl and dihydropyridine rings about the axes of the olefinic double bonds and the resultant nonradiative decay process, but they exhibit strong fluorescence in the aggregate state because of the restriction of intramolecular rotation (RIR), as confirmed by solution thickening and cooling experiments. Compared with the almost-planar dicyanomethylene-4H-pyran (DCM) derivative DCM-1 with aggregation-caused quenching (ACQ), DCMP-5 with AIE takes a highly twisted conformation by replacing the oxygen atom of the DCM skeleton with an N-ethyl group, as revealed by crystallographic data and theoretical calculations. Depending on the different electron-donating substituents, the solids of these compounds emit yellow or orange fluorescence. Moreover, the cyano group endows DCMP-5 ...

A series of new lanthanoid thioarsenates [Ln(teta)(μ-η(1):η(2):η(1)-As(III)S3)]n {Ln = Ce (Ia), Pr (Ib), Nd (Ic), and Sm (Id); teta = triethylenetetramine} and [Ln(teta)(en)(μ-η(1):η(1):η(1)-As(V)S4)]n {Ln = La (IIa), Ce (IIb), Pr (IIc), and Nd (IId); en = ethylenediamine} were prepared by the solvothermal reaction of K3AsO3, S, LnCl3 and organic amines and structurally characterized. Compounds Ia–d crystallise in the orthorhombic space group Aba2 and display 1-D neutral chains [Ln(teta)(μ-η(1):η(2):η(1)-As(III)S3)]n, which represent the first examples of 1-D organic hybrid lanthanoid sulfides built up from trigonal-pyramidal [As(III)S3](3-) acting as tetradentate bridging ligands to interlink [Ln(teta)](3+) ions, while compounds IIa–d crystallise in the orthorhombic space group P2(1)2(1)2(1) and consist of other 1-D neutral chains [Ln(teta)(en)(μ-η(1):η(1):η(1)-As(V)S4)]n, which are built up from the linkages of the tetrahedral [As(V)S4](3-) ion and the [Ln(teta)(en)](3+) ion. To learn more about the influence of lanthanide contraction on the formation of lanthanoid thioarsenates, three organic hybrid lanthanoid thioarsenates [Ln(teta)(en)As(V)S4] [Ln = Dy (IIIa), Ho (IIIb), and Tm (IIIc)] with the neutral molecular structure type in the monoclinic centrosymmetric space group P2(1)/c are also presented. Their optical and magnetic properties have been investigated, and density functional theory calculations of Ia and IIa have also been performed.

A series of new lanthanoid selenidoantimonates(V) [Ln(en)(tepa)SbSe4] (Ln = La (Ia), Ce (Ib), Pr (Ic); en = ethylenediamine, tepa = tetraethylenepentamine) and [Ln2(tepa)2(μ-OH)2Cl2]-{[Ln(tepa)]2(μ-OH)2(SbSe4)2} (Ln = Y (IIa), Sm (IIb), Gd (IIc), Tb (IId), Dy (IIe), and Tm (IIf)) were solvothermally synthesized and structurally characterized. The structures of Ia-c consist of neutral molecules [Ln(en)(tepa)SbSe4], where the tetrahedral [SbSe4](3-) anion acts as a ligand to chelate the [Ln(en)(tepa)](3+) cation. The structures of IIa-f contain isolated dinuclear [Ln2(tepa)2(μ-OH)2Cl2](2+) cations built up from two [Ln(tepa)Cl](2+) ions linked by two -OH bridging groups and organic decorated {[Ln(tepa)]2(μ-OH)2(SbSe4)2}(2-) anions based on two [Ln(tepa)SbSe4] units bridged by two -OH groups. Although a few lanthanoid selenidoantimonates(V) under solvothermal conditions have been reported, their lanthanide complexes normally appear mononuclear. Hence, IIa-f are rare examples of lanthanoid selenidoantimonates based on dinuclear lanthanide complexes. A preliminary investigation of nine lanthanoid selenidoantimonates(V) shows that the well-known lanthanide contraction has a significant influence on the formation of lanthanoid selenidoantimonates(V) under solvothermal conditions. The absorption edges of all compounds have been investigated by UV-vis spectroscopy, and density functional theory calculations for Ia and IIc have also been performed.

We report a flexible metal-organic framework (MOF), (Me2NH2)(3)[ Eu-3(MHFDA)(4)(NO3)(4)(DMF)(2)]center dot 4H(2)O center dot 2MeCN (1) (H(2)MHFDA = 9-methyl-9-hydroxy-fluorene-2,7-dicarboxylic acid), which was synthesized by a hydrothermal method and structurally characterized. This MOF has a three-dimensional framework structure with one-dimensional rhombic channels and the framework can be reversibly transformed between two phases upon release/uptake of the guest molecules. The vacuum drying process is accompanied by the loss of luminescence of the MOF, while the luminescence is recovered upon resoaking in DMF. The potential of the material for PA sensing was studied in DMF through the luminescence quenching experiments, which elucidate that this material is a potential turn-off luminescent sensory material for the selective detection of PA.

A chiral phosphoric acid promoted enantioselective NMR recognition and determination of indoloquinazoline alkaloids phaitanthrin A, cephalanthrin-A and their analogues was described, which conveniently reveals their optical purities with high accuracy. Besides, pyrazine type tertiary alcohols, cyclic amino alcohols and diamines can also be well resolved under optimal conditions. Importantly, this methodology was further employed in the direct analysis of reaction mixtures of amino acid metal salt catalyzed asymmetric synthesis of phaitanthrin A, providing access to the optimized reaction conditions in high efficiency.

The structures and properties of two mononuclear Dy(III) enantiomeric pairs were dramatically controlled by crystallization temperature; the enantiomeric pair with coordinated chiral N,N′-donor ligands exhibits enhanced single-ion magnetic, ferroelectric and chiroptical properties with respect to the other one with protonated chiral N,N′-donor ligands.

Two carboxylato-bridged allomeric compounds, ([Cu{sub 2}(dbsa){sub 2}(hmt) (H{sub 2}O){sub 4}]{sub 1/2}·2H{sub 2}O){sub n} (1), ([Ni(dbsa)(H{sub 2}O){sub 2}]{sub 1/2}[Ni(dbsa)(hmt)(H{sub 2}O){sub 2}]{sub 1/2}·2H{sub 2}O){sub n} (2) (H{sub 2}dbsa=meso-2,3-dibromosuccinic acid, hmt=hexamethylenetetramine) have been synthesized and characterized by X-ray structral analyses. The metal ions have two kinds of coordination fashion in one unit, and bridged by carboxylate and hmt ligands along with weak interactions existing in the solid structure, forming a 3-D supramolecular network. Variable-temperature magnetic property studies reveal the existence of antiferromagnetic interactions in 1 and 2 with g=2.2, J{sub 1}=−3.5 cm{sup −1}, J{sub 2}=−2.8 cm{sup −1} for 1, and g=2.1, J=−3.5 cm{sup −1} for 2. - Graphical abstract: Variable-temperature magnetic property studies of two 3-D supramolecular compounds reveal the existence of antiferromagnetic interactions between the metal ions, through the effective super-exchange media. - Highlights: • Two 3-D allomeric Cu(II) and Ni(II) metal–organic compounds have been prepared. • The 3-D networks were constructed by coordination bonds, weak interactions and hydrogen bond interactions. • There are antiferromagnetic super-exchange interactions between the metal ions.

Three new cadmium(II) coordination complexes, namely, [Cd2(1,2-bix)4(L)4]n (1), [Cd(1,3-bix)(L)2]n·H2O (2), [Cd(1,4-bix)(L)2H2O)]n·2.5H2O (3) have been synthesized using 4-carboxybenzaldehyde (HL) and 1,n-bis(imidazol-l-ylmethyl)benzene (1,n-bix; n = 2, 3, 4) as ligands. These complexes were structurally characterized by single-crystal X-ray crystallography and further characterized by FT-IR spectroscopy and thermogravimetric analysis (TGA). Complex 1 is a binuclear, complex 2 possesses a 1D double chain. Compound 3 features a 1D zigzag chain, assembled into a 2D layer structure by weak π–π interactions. The photoluminescent properties of the compounds 1–3 were also investigated.