Search

An MOF with an optimized C3H6 nano-trap exhibited a high capacity to bind C3H6 and high C3H6/C3H8 selectivity at 298 K.

Overcoming thermal quenching is an essential issue in the practical application of luminescent materials. Herein, we found that negative thermal expansion (NTE) can achieve the thermal enhancement of luminescence in molecular materials based on three metal-organic frameworks CuX-bpy (X = Cl, Br, I; bpy = 4,4'-bipyridine). All complexes exhibit NTE on the

Four coordination polymers with similar 1D chain motifs exhibited different photosalient behaviors, which can be tuned via monomer preorganization.

One Zn(ii) coordination polymer is used to selectively detect CrO42− and Fe3+ in water via luminescence quenching and enhancement methods.

Solvothermal reactions of cadmium salts with bipyridyl diene and triene ligands[(1,3-bis((E)-2-(pyridin-4-yl)vinyl)benzene-(1,3-bpeb) and 1,6-bis(4-pyridyl)-1,3,5-hexatriene(bphte)] and one bipyridyl triene ligand[1,6-bis(4-pyridyl)-1,3,5-hexatriene-(bphte)] in the presence of auxiliary carboxylic acids including 2,6-dichlorobenzoic acid(2,6-HDCBA) and 2-naphthal-enecarboxylic acid(2-HNCA) gave rise to four coordination polymers [Cd(bphte)(2,6-DCBA)2]n(1), {[Cd(bphte)(2-NCA)2]·5.8H2O}n(2), [Cd2(1,3-bpeb)2(2,6-DCBA)4]n(3) and {[Cd4(1,3-bpeb)4(2-NCA)7(HCOO)]·2-HNCA·H2O}n(4), respectively. Compounds 1–4 were structurally characterized by elemental analysis, IR, 1H NMR, powder X-ray diffraction, thermogravimetric analysis and single-crystal X-ray diffraction. They possess one-dimensional linear(1, 2) and zigzag(3, 4) chain structures. Their luminescent properties were explored while the representative sample 4 exhibited good luminescent performance in sensing Fe(III) in water.

Reactions of (NH4 )2 WS4 with CuCN, CuCN/1,2-bis(4-pyridyl)propane (bppa) or [Cu(MeCN)4 ]PF6 /bppa under different reaction conditions afforded a set of two- or three-dimensional W/Cu/S cluster-based coordination polymers including {[Et4 N]2 [WS4 Cu4 (μ-CN)2 (μ-I)2 ]}n (1), [WS4 Cu4 (μ-CN)2 (bppa)2 ]n (2) and {[WS4 Cu4 (bppa)4 ](PF6 )2 }n (3), respectively. Compound 2 can be readily formed from reaction of 1 with bppa under solvothermal conditions. Compounds 1 and 2 feature two-dimensional networks with a "sql" topology, while 3 possesses a two-fold interpenetrated three-dimensional net with a rare "reo" topology. Compounds 1-3 in DMF exhibited different third-order nonlinear optical responses, and they all showed a reverse saturable absorption while 2 held a strong self-focusing effect.

Two atom-precise silver nanoclusters [Ag25Cl2(Tab)14(PhCOO)11(DMF)4](PF6)12 (Ag25, DMF=N,N-dimethylformamide) and [Ag26Cl2(Tab)14(PhCOO)13(DMAc)4](PF6)11(Ag26, DMAc=N,N-dimethylacetamide) were synthesized based on the electrically neutral thiolate protective ligand, 4-(trimethylammonio)benzenethiolate (Tab). The weak Ag-S interaction in Tab-protected silver nanoclusters allows to insert or leave a single silver atom in the Ag-S skeleton through solvent-trigger core fragmentation and re-arrangement, thereby realizing the reversible conversion of Ag25 and Ag26 for the first time.

The treatment of the metal sulfide precursor [Et4N][Tp*WS3] (Tp* = hydridotris(3,5-dimethylpyrazol-1-yl)borate) (1) with Cu(I) and the Fe-bipyridine complex ligand L1 in the presence of (NH4)2SO4 produced one-dimensional (1D) [(Tp*WS3Cu2)2(L1)2](BF4)2 (2) and two-dimensional (2D) [(Tp*WS3Cu3)2(L1)3(μ3-SO4)2] (3) heterometallic coordination polymers (CPs). Both CPs were characterized using elemental analysis, IR spectra, UV-vis spectra, mass spectra and single crystal X-ray diffraction. Compound 2 contains a butterfly-shaped core [Tp*WS3Cu2] serving as a two-connecting node to link its equivalent ones viaL1 bridges to form a 1D zigzag chain extending along the c axis. Compound 3 consists of a 2D layer structure with a (6,3) network in which each complete cubane-like core [Tp*WS3Cu3(μ3-SO4)] works as a pyramidal three-connecting node to link its equivalent ones viaL1 bridges. The formation of the different structural topologies of 2 and 3 may be ascribed to the different precursor-to-Cu(I) molar ratios (1 : 2 for 2 and 1 : 3 for 3). The cluster modular construction (CMC) was used to simplify the structural modules of 2 and 3 as straightforward modules to clarify the possible process of assembly and structural characteristics. In addition, the third-order nonlinear optical (NLO) properties of 2 and 3 in MeCN were investigated. They both displayed enhanced third-order NLO responses relative to those of 1 and L1.

Discovering and constructing novel and fancy structures is the goal of many supramolecular chemists. In this work, we propose an assembly strategy based on the synergistic effect of coordination and covalent interactions to construct a set of octahedral supramolecular cages and adjust their degree of distortion. Our strategy innovatively utilizes the addition of sulfur atoms of a metal sulfide synthon, [Et4N][Tp*WS3] (A), to an alkynyl group of a pyridine-containing linker, resulting in a novel vertex with low symmetry, and of Cu(I) ions. By adjusting the length of the linker and the position of the reactive alkynyl group, the control of the deformation degree of the octahedral cages can be realized. These supramolecular cages exhibit enhanced third-order nonlinear optical (NLO) responses. The results offer a powerful strategy to construct novel distorted cage structures as well as control the degree of distortion of supramolecular geometries.

Diethyl 2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylate (HEH) has been utilized as a visible-light photoredox catalyst for the cross coupling of arylhalides and arylsulfinates without transition metal, sacrificial agent, and mediator. This method is compatible with various functional groups and provides diaryl sulfones in good to high yields. Mechanistic studies indicate that this reaction undergoes the stepwise light irradiation of HE- , single electron transfer (SET) in donor-acceptor complex (DAC) from *HE- to arylhalide, trapping of aryl radical with sulfinate, and SET oxidation of sulfone radical anion by HE. to sulfone by the DAC method.

A conjugated nanoporous polycarbazole (CNP) cross-linked by pyridine and coordinated to Co(III) displays high catalytic performance for visible light-driven H2 generation. The hydrogen evolution rate was up to 410 μmol g−1 h−1. Spectroscopic and electrochemistry studies indicate that the redox active cobalt reduces recombination of photoexcited-charge-carriers and enhances the transmission of photoexcited-charge, thereby enriching the catalytic activity of hybrid materials x-Co/CNP-N (x = 5, 10, 15 and 20 wt%).

Solid-state photochemical reactions of olefinic compounds have been demonstrated to represent powerful access to organic cyclic molecules with specific configurations. However, the precise control of the stereochemistry in these reactions remains challenging owing to complex and fleeting configuration transformations. Herein, we report a unique approach to control the regiospecific configurations of C = C groups and the intermediates by varying temperatures in multiple-step thermal/photoinduced reactions, thus successfully realizing reversible ring closing/opening changes using a single-crystal coordination polymer platform. All stereochemical transitions are observed by in situ single-crystal X-ray diffraction, powder X-ray diffraction and infrared spectroscopy. Density functional theory calculations allow us to rationalize the mechanism of the synergistic thermal/photoinduced transformations. This approach can be generalized to the analysis of the possible configuration transformations of functional groups and intermediates and unravel the detailed mechanism for any inorganic, organic and macromolecular reactions susceptible to incorporation into single-crystal coordination polymer platforms.

To obtain a pure product without the isomer byproducts is a goal that many chemists are pursuing. As one kind of very important synthesis method, the photochemical reaction is simple and straightforward yet low-selective. In this work, a coordination interaction-based oriented synthesis strategy has been proposed to realize the precise stereochemical control of the isomeric cyclic compounds in the photocycloaddition reaction. Through fixing the reactants via coordination interactions, the arrangements and configurations of the reactants can be adjusted, thereby successfully producing all of the related photocycloaddition products without isomer byproducts for the first time. This work not only provides a new route to synthesize the pure cyclic compounds but also expands the application of the photocycloaddition reaction.

The photoinduced dynamic behavior of flexible materials has received considerable attention for potential applications, such as in data storage or as smart optical devices and molecular mechanical actuators. Until now, precisely controlling expansion and contraction with light has remained a challenge. Unraveling the detailed mechanisms of photoinduced structural transformations remains a critical step necessary to understand the molecular architecture necessary for the design of sensitive photomechanical actuators. Herein, a two-dimensional flexible metal-organic framework [Zn2 (bdc)2 (3-CH3 -spy)2 ]⋅H2 O (Zn2 -1; H2 bdc=1,4-benzenedicaboxylic acid; 3-CH3 -spy=3-methylstyrylpyridine) with a positive volumetric thermal expansion coefficient of +78.78×10-6 K-1 is reported. Upon light irradiation at different wavelengths, the MOF underwent a [2+2] cycloaddition, which afforded a family of isomeric, three-dimensional MOFs (Zn2 -2 n, n=a-d) in a single-crystal-to-single-crystal (SCSC) manner. An unprecedented phenomenon, that is, photoinduced nonlinear contraction (PINC), was observed during this conversion. The PINC is caused by conformational changes in the 3-CH3 -spy and bdc2- ligands, the bending of metal-ligand bonds, and the local distortion of the paddle-wheel SBUs. The formation of a "wrinkle morphology" on the crystal surface after the photoreaction was observed by AFM. This PINC behavior can broaden the studies on materials expansion and offer a photodriven approach for the future design of supersensitive photomechanical actuators.

Three fluorescent coordination polymers (CPs) including [Zn(ppvppa)(5-NO2-1,3-BDC)(H2O)] (1), [Cd(ppvppa)2(2,5-FDC)]·1.5H2O (2), and [Ni(ppvppa)(5-NO2-1,3-BDC)(H2O)]·0.5MeCN (3) (ppvppa = dipyridin...

Tetraphosphine ligand dpppda reacts with AgNO3 to generate two 1D coordination polymers containing cubic and chair-like [Ag4(NO3)4] clusters. ESR spectroscopy supported by DFT calculations indicated the presence of dpppda˙+, a Wurster's blue - like radical cation formed by intramolecular ligand-to-metal charge transfer (LMCT). This LMCT results in higher AgI → Ag0 potentials and good photocurrent responses.

We herein report three isoreticular Tp*–W–Cu–S cluster-based one-dimensional coordination polymers, namely, [Tp*WS3Cu2(CN)2Cu](pz)0.5 (2), [Tp*WS3Cu2(CN)2Cu](bipy)0.5·0.5DMF (3), and [Tp*WS3Cu2(CN)2Cu](bpb)0.5·DMF (4), from the reaction of [Et4N][Tp*WS3] (1) with CuCN in the presence of bridging ligands pyrazine (pz), 4,4′-bipyridine (bipy), and 1,4-bis(4-pyridyl)benzene (bpb) under solvothermal conditions. In 2–4, a pair of butterfly-shaped [Tp*WS3Cu2]+ clusters are connected by two [Cu(CN)2]− units to give a macrocyclic unit, which is further strung by pz/bipy/bpb to give linear chains. Besides their rare isoreticular nature, 2–4 are also unique in that they contain a [Tp*WS3Cu2] + [Cu] combination instead of the widely acknowledged nest-shaped [Tp*WS3Cu3]2+ or cuboidal [Tp*WS3Cu3X]+ (X = Cl, Br, I) cluster skeleton. Compounds 2–4 are also characterized by FT-IR, elemental analysis, UV-vis and ESI-MS. The ESI-MS results also indicate that the pz/bipy/bpb coordination is labile in solution under harsh ionization conditions, yielding CN-ligated anionic species which are assumed as the key contributors to the enhanced NLO performance of 2–4 compared to that of the starting material 1.

The single-crystal to single-crystal (SCSC) conversion of metal–organic frameworks (MOFs) represents a facile route to new MOFs with structures and functionalities that are challenging to obtain by direct synthesis. However, conversion products are often structurally limited for a given precursor. We herein report that a two-dimensional (2D) MOF featuring a linear Cd3 cluster secondary building unit (SBU) converts into one type of three-dimensional (3D) interpenetrated and two types of 3D non-interpenetrated MOFs upon reaction with dipyridyl ligands. One of the interpenetrated 3D MOFs, in turn, undergoes either ligand substitution to give isoreticular interpenetrated MOFs, or ligand addition to give a self-penetrated 3D MOF. This rich SCSC conversion library is made possible by the inclined nature of the Cd3 SBU with respect to the 2D plane of the starting material to create an anisotropic environment around the SBU.

Reactions of Zn(OAc)2·2H2O with N1,N4-bis(5-fluoropyridin-3-yl)succinamide (bfps) and 1,2,3-benzenetricarboxylic acid (1,2,3-H3BTC) or 1,3,5-benzenetricarboxylic acid (1,3,5-H3BTC) under hydrothermal conditions produce two Zn(II)-based coordination polymers (CPs), {[Zn3(bfps)(1,2,3-BTC)2(H2O)6]·4H2O}n (1·4H2O) and {[Zn(bfps)(1,3,5-HBTC)]·H2O}n (2·H2O). Both compounds show two-dimensional layer structures derived from interconnecting dinuclear [Zn2(1,2,3-BTC)2(H2O)2] units through the bfps bridges and the [Zn(H2O)4] species (1·4H2O) or interlinking dinuclear [Zn2(1,3,5-HBTC)2] units via pairs of bfps bridges and pairs of 1,3,5-HBTC dianions (2·H2O). They display high absorptive capacities toward Orange IV (OIV) in water, i.e., 718 mg·g–1 (1·4H2O) and 794 mg·g–1 (2·H2O), respectively. The resulting CP-OIV composites with the chemical formulas of 1·2.0OIV (3) and 2·1.1OIV·2.5H2O (4) exhibit enhanced photocurrent responses in relation to those of the two precursors.

The photochemical [2+2] cycloaddition of 3,5-bis-(2-(pyridin-4-yl)vinyl)pyridine (bpvp) in the flexible Cd-based metal-alkene frameworks produced different isomeric photoproducts depending on the auxiliary and guest molecules. The bulkiness of the guest molecules influenced the conformation of the ligand, and thus the outcome of the cycloaddition reaction.

Light-up luminescence sensors have been employed in real-time in situ visual detection of target molecules including volatile organic compounds (VOCs). However, currently employed light-up sensors, which are generally based on the aggregation-induced emission (AIE) or solvent-induced energy transfer effect, exhibit limited sensitivity for light-up detection and poor recycling performances thereby significantly hindering their industrial applications. Inspired by the low-temperature enhanced luminescence phenomenon, we herein propose and show that a guest-lock-induced luminescence enhancement mechanism can be used to realize the ultrafast light-up detection of target VOCs. Through introduction of chlorinated hydrocarbons to lock the molecular vibrations within a designed [Cu4I4]-based metal-organic framework (MOF), luminescence intensity could be enhanced significantly at room temperature. This guest-lock-induced luminescence enhancement is brought about by weak supramolecular interactions between the host framework and the guest molecules, allowing highly sensitive and specific detection of the guest vapor with ultrafast response time (

A novel ligand-stabilized Ag12 nanocluster was synthesized as a model cluster to investigate the solvent-induced isomerization of Ag12 clusters. Another two novel Ag12 clusters as well as their related symmetry transformations were also successfully obtained through the above solvent-induced isomerization process.

As an important two-dimensional material, layered double hydroxides (LDHs) show considerable potential in electrocatalytic reactions. However, the great thickness of the bulk LDH materials significantly limits their catalytic activity. In this work, we report ultrathin NiFe-LDH nanosheets with sulfate interlayer anions (Ni6Fe2(SO4)(OH)16·7H2O) (U-LDH(SO42−)), which can be synthesized in gram-scale by a simple solvothermal method. The U-LDH(SO42−) shows excellent stability and great electrocatalytic performance in OER with a current density of 10 mA cm−2 at a low overpotential of 212 mV and a small Tafel slope of 65.2 mV dec−1, exhibiting its great potential for a highly efficient OER electrocatalyst.

Regioselective photodimerization of trans-4-styrylpyridine (4-spy) derivatives is performed using pseudorotaxane-like Zn-based metal organic frameworks MOFs as templates. The formation of rctt-HT (head-to-tail) dimers is achieved by confining pairs of coordinated 4-spy derivative ligands within hexagonal windows and then irradiating them with UV light. It is also possible to achieve a photodimerization reaction where two different substituted 4-spy ligands are included in such a MOF material. The ether bond formation is employed to protect the sensitive -OH group of HO-spy and the methyl group of CH3 O-spy is subsequently removed after the formation of cyclobutane derivative in the CH3 O-spy-based MOF. Introducing substituents at the 2- or 3-position of the phenyl group of 4-spy does not significantly affect the rate of the dimerization process except in the case of the strongly electron-withdrawing nitro group where the rate is significantly decreased. These results are in striking contrast to the mixtures of photoproducts and low yields obtained by untemplated photodimerization in organic solvents.

Solvothermal reactions of zinc and cadmium nitrates with 1,3,5-tri-4-pyridyl-1,2-ethenylbenzene (tpeb) in the presence of various carboxylic acids including 4-iodobenzoic acid (4-HIBA), benzene-1,4-dicarboxylic acid (1,4-H2BDC), 2,5-furandicarboxylic acid (2,5-H2FDC), 2,5-dibromoterephthalic acid (2,5-H2DBTPA), 1,2-cyclohexanedicarboxylic acid (1,2-H2CHDC), and 1,5-pentanedioic acid (1,5-H2PDC) gave rise to eight coordination complexes, viz, [Zn(tpeb)2(4-IBA)2]·2H2O (1), {[Cd(NO3)(tpeb)(4-IBA)]·H2O}n (2), {[Cd2(NO3)2(tpeb)2(1,4-BDC)]}n (3), {[Cd2(tpeb)2(2,5-FDC)2]·2H2O}n (4), [Cd(tpeb)(2,5-DBTPA)2]n (5), {[Cd2(H2O)2(tpeb)2(1,2-CHDC)2]·H2O}n (6), [Zn(tpeb)(1,2-CHDC)]n (7), and {[Zn(tpeb)(1,5-PDC)]·H2O}n (8). Compound 1 is a discrete mononuclear complex with its Zn(II) center coordinated by two pairs of tpeb and 4-IBA ligands. Compound 2 has a 2D waterfall-like network constructed from bridging [Cd(NO3)(4-IBA)] units with tpeb ligands. Compounds 3, 4, and 5 contain similar 1D [Cd(tpeb)]n chains, which are l...

2,3,7,8,12,13,17,18-Octabromo-5-(2-nitrophenyl)-10,15,20-triphenyl porphyrin (H[Formula: see text]OBP-NO[Formula: see text] and its metallic complexes have been designed and synthesized. Both the free-base porphyrin and its iron(III) complex have been characterized by X-ray crystallography. Structures confirm there are three phenyl groups and one 2-nitrophenyl at meso positions and eight bromine atoms at [Formula: see text]-pyrrole positions. The crowded substituents cause the porphyrin plane to be distorted and become saddle shaped. The complexes were also characterized by NMR and UV-vis spectra. The UV-vis spectrum of the free-base porphyrin shows that substitution by eight bromine atoms at [Formula: see text]-pyrrole positions leads to a red shift of the bands.

Summary Efficient oxygen reduction reaction (ORR) catalysts are key for the development of high-performance fuel cells. Palladium (Pd) is a promising catalyst system for ORR given its potential to replace platinum (Pt); however, it usually exhibits lower activity than Pt. Here, we report a class of ordered Pd 3 Pb tripods (TPs) with predominantly {110} facets and show that they achieve extremely high ORR performance in alkaline medium. In contrast to the knowledge that the excellent ORR activity of Pt catalyst is caused by its partially filled d orbital, our first-principle calculations suggest that the strong charge exchange between Pd-4 d and Pb-( sp ) orbitals on the Pd 3 Pb TPs {110} facet results in a Pd-Pb local bonding unit with an orbital configuration similar to that of Pt. Consequently, Pd 3 Pb TPs exhibit much higher ORR activities than commercial Pt/C and commercial Pd/C. Pd 3 Pb TPs are endurable and sustain over 20,000 potential cycles with negligible structural and compositional changes.

Reaction of [Et4N][Tp*WS3] (1) with [Cu(MeCN)4]PF6, CsCl, isonicotinic acid and CuCN, and treatment of [Et4N][Tp*WS3(CuCl)3] (2)/[Et4N][{Tp*WS3Cu3Cl}2(μ-Cl)2(μ4-Cl)] (3) with AgOTf and bpp (Tp* = hydridotris(3,5-dimethylpyrazol-1-yl)borate; bpp = 1,3-di(4-pyridyl)propane) give rise to [Et4N]2[{Tp*WS3Cu3(CN)0.5}2(μ-Cl)2(μ4-Cl)]2(PF6)2 (4) and [(Tp*WS3Cu3)2(μ3-Cl)2(bpp)3]2(OTf)4 (5), respectively. Compounds 4 and 5 feature cluster-based rectangle and [2]catenane architecture, and both exhibit enhanced third-order nonlinear optical responses relative to those of 1.

A new P–N hybrid ligand N-diphenylphosphanylmethyl-3-aminopyridine (3-dppmapy) is synthesized and allowed to react with six silver oxysalts including AgTFA (TFA = trifluoroacetic), AgOTF (OTF = trifluoromethanesulfonic), AgNO3, Ag2SO4, AgBz (Bz = benzoate) and AgSal (Sal = salicylate). The reactions result in the formation of two dinuclear complexes [Ag2(Ox)2(3-dppmapy)2] (1, Ox = TFA; 2, Ox = OTF) and four 1D coordination polymers Ag(μ-η2-NO3)(3-dppmapy)·EtOH (3·EtOH), [Ag2(μ-η,η-SO4)(3-dppmapy)2]·CHCl3 (4·CHCl3), [Ag(μ-η2-Bz)(3-dppmapy)] (5) and [Ag(μ-η2-Sal)(3-dppmapy)] (6). All six compounds have energy bands between 3.11–3.43 eV which is in the range of semiconductive materials, whereas only 6 exhibits good stability in water solution under UV irradiation. In the aqueous phase, 6 exhibits high photocatalytic performance in the degradation of eriochrome black T (EBT), amido black (AB) and nigrosin (NO), and also shows relatively prompt anodic photocurrent responses.

Metal-organic frameworks (MOFs) are a class of promising materials for diverse catalysis, but they are usually not directly employed for oxygen evolution electrocatalysis. Most reports focus on using MOFs as templates to in-situ create efficient electrocatalysts via annealing. Herein, we prepared a series of Fe/Ni/-based trimetallic MOFs (Fe/Ni/Co(Mn)-Material of Institute Lavoisier (MIL-53)) by solvothermal synthesis, which can be directly adopted as electrocatalysts. It was revealed that the Fe/Ni/Co(Mn)-MIL-53 exhibited volcano-type oxygen evolution reaction (OER) activity as a function of compositions. The optimized Fe/Ni2.4/Co0.4-MIL-53 can reach the current density of 20 mA*cm-2 at low overpotential of 236 mV with small Tafel slope of 52.2 mV*dec-1. The OER performance of these MOFs can be further enhanced by directly being grown on nickel foam (NF), in which the optimized Fe/Ni/Mn0.4-MIL-53/NF exhibits low overpotential of 290 mV at 500 mA*cm-2 as well as high durability.

Treatment of N,N-bis(diphenylphosphanylmethyl)-3-aminopyridine (3-bdppmapy) with AgX (X = Br, I, CN, SCN, dicyanamide (dca)) under different reaction conditions afforded seven mononuclear, dinuclear, and polymeric coordination complexes including [Ag4I4(3-bdppmapy)2]n (1), [Ag2I2(3-bdppmapy)3]·CH3OH (2·CH3OH), [Ag2Br(3-bdppmapy)3]Br·4CH3OH (3·4CH3OH), [Ag4(CN)4(3-bdppmapy)3]·2CH3OH (4·2CH3OH), [Ag(3-bdppmapy)2]SCN (5), [Ag(3-bdppmapy)2](dca) (6), and {[Ag4(dca)4(3-bdppmapy)2]·4DMF}n (7). Compound 1 contains a unique two-dimensional (2D) network in which chairlike [Ag4I4] units are interconnected by μ3-3-bdppmapy bridges. Compounds 2 and 4 hold a similar centrosymmetric framework in which two [(3-bdppmapy)AgI] (2) or [(3-bdppmapy)Ag2(CN)2] (4) units are linked by a μ-3-bdppmapy. Compound 3 has a batlike cationic structure in which two Ag/3-bdppmapy units are joined by a pair of μ-Br and μ-3-bdppmapy bridges. Compounds 5 and 6 have a similar cationic mononuclear structure in which the Ag(I) center is chelat...

Solvothermal reactions of Zn(NO3)2·6H2O with 1,4-bis(2-(pyridin-4-yl)vinyl)naphthalene (1,4-bpyvna) and 1,3,5-benzenetricarboxylic acid (1,3,5-H3BTC) (molar ratio = 1:1:1) at 120 °C in CH3CN/H2O (v/v = 1:2) afforded one three-dimensional (3D) coordination polymer [Zn2(1,4-bpyvna)(1,3,5-HBTC)2(H2O)]n (1). Similar reactions with the same three components at 140 °C in dimethylformamide (DMF)/CH3CN/H2O produced another 3D coordination polymer {[Zn2(1,4-bpyvna)(1,3,5-BTC)(OH)]·H2O}n (2) in 72% yield. When the molar ratio of Zn(NO3)2·6H2O, 1,4-bpyvna, and 1,3,5-H3BTC was changed to 1:1:2, the analogous treatment at 140 °C yielded one one-dimensional coordination polymer {[Zn(1,3,5-HBTC)2(H2O)][1,4-bpyvna-H2]·CH3CN}n (3, 1,4-bpyvna-H2 = 4,4′-((1,1′)-naphthalene-1,4-diylbis(ethene-2,1-diyl))bis(pyridin-1-ium)). Solvothermal reactions of Zn(NO3)2·6H2O with equimolar 1,4-bpyvna and 1 or 2 equiv of 4,4′-oxidibenzoic acid (4,4′-H2OBA) at 120 °C in DMF/CH3CN/hexane resulted in the formation of {[Zn2(1,4-bpyvna)(4,4′-O...

A green protocol for the synthesis of quinoxalines has been developed from catalytic oxidative cyclization of deoxybenzoins with 1,2-phenylenediamines in water. The optimal conditions are involved in the use of a water-soluble mononuclear copper(II) complex of a zwitterionic calix[4]arene [Cu(II)L(H 2 O)]I 2 ( 1 , H 4 L = [5,11,17,23–tetrakis (trimethylammonium)–25,26,27,28–tetrahydroxycalix[4]arene]) as a catalyst in alkali solution after refluxing for 15 h in O 2 . The target quinoxaline and its derivatives were obtained in good yields (up to 88%). The procedure described in this paper is simple, practical and environmentally benign.

Two β,β′-linked porphyrin-chlorin heterodimers have been successfully synthesized with 4-fluorophenyl or 4-chlorophenyl substituted aldehyde as starting reagents. But those aldehydes with bulkier substituents did not lead to the corresponding heterodimers. These porphyrin-chlorin heterodimers and their metallic complexes have been characterized by X-ray crystallography. In all the structures, the pyrroline group in chlorin moiety and the pyrrole group in porphyrin moiety are directly connected by a single bond. Pyrroline ring has two sp[Formula: see text] hybridized carbons. The direct bonding makes the porphyrin and chlorin moieties closely contact with each other, pyrroline group and the pyrrole group forms a dihedral angle of ~70°. If porphyrin-chlorin heterodimers have bulkier substituents, the close contact could cause too much repulsion. That is probably why they can not be synthesized. For nickel complexes, the chlorin planes show large saddling and moderate ruffling conformation. The C–H⋯[Formula: see text] interaction could contribute to the saddling conformation. The distorted core makes dihedral angles and metal to metal distances between porphyrin and chlorin plane much smaller than those in their copper complexes. Their NMR, UV-visible and fluorescence spectral data have also been briefly discussed.

Solvothermal reactions of Cd(NO3)2·4H2O with 4-pyr-poly-2-ene (ppene) in the presence of benzene-1,2-dicarboxylic acid (1,2-H2BDC), benzene-1,3-dicarboxylic acid (1,3-H2BDC), benzene-1,4-dicarboxylic acid (1,4-H2BDC), benzene-1,3,5-tricarboxylic acid (1,3,5-H3BTC), or 4,4′-oxidibenzoic acid (4,4′-H2OBA) afforded five Cd(II) coordination polymers [Cd(ppene)(1,2-BDC)]n (1), [Cd(ppene)(1,3-BDC)]n (2), [{Cd(ppene)(1,4-BDC)}·MeCN]n (3) (Liu et al. Inorg. Chem. Commun. 2015, 58, 1−4), [{Cd(ppene)(1,3,5-HBTC)}·0.5(ppene)]n (4), and [Cd(ppene)(4,4′-OBA)]n (5), respectively. Upon UV light irradiation, 1, 3, and 4 can undergo a double [2 + 2] cycloaddition reaction to yield their corresponding photoproducts including [Cd2(4-tp-3-lad)(1,2-BDC)2]n (1a, 4-tp-3-lad = 2,3,5,6-tetra(pyridin-4-yl)bicyclo[2.2.0]hexane), [{Cd2(4-tp-3-lad)(1,4-BDC)2}·2MeCN]n (3a), and [{Cd2(4-tp-3-lad)(1,3,5-HBTC)2}·(ppene)]n (4a) in a single-crystal-to-single-crystal manner. Compounds 1, 2, 4, 5, 1a, 3a, and 4a have been structurally charac...

A series of Fe(III) complexes of β-diketonate ligands, 1-(2-pyridyl)-3-(3-pyridyl)-1,3-propanedione (L1), 1-(2-pyridyl)-3-(2-pyridyl)-1,3-propanedione (L2), 1-(2-pyridyl)-3-(4-pyridyl)-1,3-propanedione (L3), 1-(3-pyridyl)-3-(4-pyridyl)-1,3-propanedione (L4), 1-(3-pyridyl)-3-(3-pyridyl)-1,3-propanedione (L5) and 1-(4-pyridyl)-3-(4-pyridyl)-1,3-propanedione (L6), viz. [Fe(L1)3] (1), [Fe(L2)3] (2), [Fe(L3)3] (3), [Fe(L4)3] (4), [Fe(L5)3] (5) and [Fe(L6)3] (6) have been structurally characterized. All but one complex (1) catalyzed the ring-opening polymerization (ROP) of e-caprolactone (e-CL) in near quantitative yield at 110 °C to give polymers with relatively narrow polydispersities (PDI). The comparison of in situ reaction and a reaction with preformed 1 indicated that the latter was a better catalyst, giving a higher molecular weight. Complex 2 catalyzed this reaction in a more modest yield reflecting its greater thermal stability, shorter Fe–O bonds and minimal distortion in fold angle among the isomeric complexes, suggesting that ligand dissociation is important for catalytic activity.

The pure diolefinic ligand 1,4-bis(pyridin-4-yl)-1,3-butadiene (bpbde) is photostable in the crystalline state. With the assistance of coordination-driven metal-organic assemblies, the photoreactivity of this diolefinic ligand can be significantly enhanced. A hydrothermal reaction of bpbde with Cd(NO3 )2 ⋅4 H2 O and the auxiliary ligand adipic acid resulted in the formation of a two-dimensional photoreactive coordination polymer (CP), [Cd(adipate)(bpbde)]n (1). When the aliphatic carboxylic acid was replaced by pimelic acid, another photoreactive CP [Cd(pimelate)(bpbde)]n (2) with a three-dimensional framework was obtained. With irradiation of 365 nm UV light, the bpbde ligands in crystalline 1 and 2 underwent a regioselective photochemical [2+2] cycloaddition reaction and converted to 3,4,7,8-tetra(pyridin-4-yl)tricyclo[4.2.0.02,5 ]octane (tptco) and 1,3-bis(pyridin-4-yl)-2,4-bis(2-(pyridin-4-yl)vinyl)cyclobutane (bpbpvcb), respectively. The results provide an interesting insight into the rational design of highly regio- or stereoselective photocatalytic reactions for the formation of special organic molecules.

Ultrathin metal-organic framework (MOF) nanosheets (NSs) offer potential for many applications, but the synthetic strategies are largely limited to top-down, low-yield exfoliation methods. Herein, Ni-M-MOF (M=Fe, Al, Co, Mn, Zn, and Cd) NSs are reported with a thickness of only several atomic layers, prepared by a large-scale, bottom-up solvothermal method. The solvent mixture of N,N-dimethylacetamide and water plays key role in controlling the formation of these two-dimensional MOF NSs. The MOF NSs can be directly used as efficient electrocatalysts for the oxygen evolution reaction, in which the Ni-Fe-MOF NSs deliver a current density of 10 mA cm-2 at a low overpotential of 221 mV with a small Tafel slope of 56.0 mV dec-1 , and exhibit excellent stability for at least 20 h without obvious activity decay. Density functional theory calculations on the energy barriers for OER occurring at different metal sites confirm that Fe is the active site for OER at Ni-Fe-MOF NSs.

A two-dimensional (2D) Co-based metal-organic framework (MOF) with porphyrinic skeleton forms crystalline plates, flower-shaped clusters, and ultrathin films under optimized conditions, including the use of polyvinylpyrrolidone (PVP) as a surfactant. Ultrathin films demonstrate the best solution-based third-order nonlinear optical properties, featuring a nonlinear transmittance (T) value of 0.54, absorption coefficient (α2) of 9.5 × 10-10 m W-1 and second hyperpolarizability (γ) value of 1.37 × 10-28 esu, which are slightly better than those of the flower-shaped clusters (T = 0.65, α2 = 7.0 × 10-10 m W-1; γ = 1.27 × 10-28 esu), but marginally better than those of the crystalline thin plates (T = 0.94, α2 = 2.4 × 10-10 m W-1; γ = 0.24 × 10-28 esu).

Solvothermal reaction of Zn(NO3)2 with 2,9-bis-(2-pyridine-3-yl-vinyl)-[1,10]phenanthroline (3-bpep) and furan-2,5-dicarboxylic acid (2,5-H2FDC) afforded a one-dimensional (1D) coordination polymer {[Zn2(3-bpep)2(2,5-FDC)2]·1.5H2O}n (1), which undergoes regioselective photocycloaddition to yield another 1D coordination polymer {[Zn2(3-bpep)(trans,rctt-3-bpbpycb)0.5(2,5-FDC)2]·H2O}n (2) in a single-crystal-to-single-crystal manner under UV light irradiation. The reverse process from 2 to 1 can be achieved by heating 2 at 240 °C. Such a photocycloaddition/thermocycloreversion cycle results in an interesting reversible dielectric switching.

Coordination compounds [In(Tab)2(Phen)2](PF6)3 (2), [In(Tab)2(Phen)2⋅In(Tab)4(Phen)](OAc)6 (3) and [In(Tab)4(Phen)](OAc)3 (4) (Tab=4-(Trimethylammonio)benzenethiolate; Phen=1,10-Phenanthroline) are formed via a counterintuitive solid-state synthesis involving the mix of In(OAc)3, TabHPF6 and Phen in various stoichiometries. The Tab-to-Phen ratios of 2−4 are opposite to the TabHPF6-to-Phen ratios of the starting materials. By comparison, the corresponding solution-state reactions provide 4 exclusively at high concentrations, and otherwise the Phen-free [In(Tab)4](OAc)3 (1). Reaction of In(OAc)3, TabHPF6 and a bulkier Dpphen (Dpphen=4,7-Diphenyl-1,10-phenanthroline) ligand in the solid state give [In(Tab)2(Dpphen)2](PF6)3 (5) exclusively, regardless of the reaction stoichiometry. Compounds 2, 4 and 5 associate with two fluorophore carboxyfluorescein (FAM) probe labelled DNA fragments (P-DNAs) through electrostatic, π-stacking and/or hydrogen-bonding interactions, forming P-DNA@2, P-DNA@4 and P-DNA@5 hybrids that quench the fluorescence of FAM via a photo-induced electron transfer process. These hybrids are further used as efficient and selective “turn-on” fluorescent sensors for HIV-1 ds-DNA and Sudan Ebolavirus RNA sequences with detection limits in the pM–nM range.

We have prepared a family of [WS3Cu2]-based coordination polymers with a rare μ-N type coordination by a simple one-pot assembly of [Et4N][Tp*WS3] (1) with CuCN in the presence of pyridine (py), 4,4′-bipyridine (bipy), 1,2-bis(4-pyridyl)ethane (bpea), and 2,4,6-tri(4-pyridyl)-1,3,5-triazine (tpt) at room temperature. The resulting coordination polymers [Tp*WS3Cu2(CN)(μ-py)]2·py (2·py), [Tp*WS3Cu2(CN)2Cu(μ-py)2]2·3py (3·3py), [Et4N][{Tp*WS3(CuCN)2Cu}2(CN)(μ4-bipy)] (4), [Tp*WS3Cu2(CN)(μ4-bpea)0.5]2·CH2Cl2 (5·CH2Cl2), and [Tp*WS3Cu2(CN)(μ6-tpt)1/3]2 (6) share a butterfly-shaped [Tp*WS3Cu2] motif with sizable concave to accommodate pyridyl ligands. The approximate mirror symmetry of the motif also induces the orthogonal coalignment of the pyridyl ligands, reinforcing a unique μ-type association with the Cu centers of the cluster skeleton. Such a coordination mode, though scarce in general coordination chemistry, is universal in our series with good ligand tolerance including ligand size and symmetry. In addi...