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A new series of uranium organophosphinates has been hydrothermally synthesized by using hydroxymethyl phenylphosphinic acid (HMPPA, HL) in the presence of imidazole derivatives, namely, UO2(L)2 (HMPP-U1), (UO2)2(L)4(dib) (HMPP-U2), (UO2)2(L)2(ox)(dib) (HMPP-U3), (Hbpi)2[(UO2)4(L)6(ox)2] (HMPP-U4) and (UO2)2(L)2(ox)(bpbi)2 (HMPP-U5) (ox = oxalate, dib = 1,4-di(1H-imidazol-1-yl)benzene, bpi = 1-(biphenyl-4-yl)-1H-imidazole, bpbi = 1-([1,1'-biphenyl]-4-yl)-1H-benzo[d]imidazole). HMPP-U1 was directly synthesized through hydrothermal reaction between HMPPA and UO22+, featuring a single chain structure constructed from sole UO6 tetragonal bipyramids bridged by HMPP ligands. With further introduction of imidazole derivatives, a layered structure of HMPP-U2 is formed, in which dib molecules are coordinated to uranyl centers as bidentate coligands. By adding glycol into the synthesis, a common dimeric building unit is isolated, which comprises two U-centered pentagonal bipyramids linked by an in situ generated oxalate group. In HMPP-U3, a one-dimensional structure comprising such dimeric uranyl entities and HMPP ligands is pillared by dib, forming a layered assembly. HMPP-U4 incorporates the dimeric uranyl units connected by HMPP ligands, leading to a two-dimensional arrangement with bpi as the template. HMPP-U5 features a one-dimensional structure composed of the uranyl dimers and HMPP ligands. The bpbi molecules serving as coligands are coordinated to the chain. The syntheses and structures as well as the correlations and discrepancies of these uranyl organophosphinates are discussed in this paper. [ABSTRACT FROM AUTHOR]

A series of stimuli-responsive AIEgens of tetraphenylethylene (TPE) fused imidazole derivatives (1–7) were synthesized, and their substituent controlled fluorescence properties in the solid state were explored. The structure of the synthesised compounds was characterized by NMR, mass and single crystal X-ray diffraction spectroscopy techniques. 1–7 exhibited a typical aggregation induced emissive (AIE) behaviour in the THF : water mixture. These compounds exhibited substituent dependent strong solid state fluorescence (Φf = 16.6–55.7%) with a tunable λmax between 458 and 496 nm. Chlorine substituted 6 showed the highest fluorescence efficiency (Φf = 55.7%), whereas acetyl substituted 3 exhibited the lowest fluorescence efficiency (Φf = 16.6%). All the seven compounds showed a mechanical pressure induced reversible fluorescence switching. Crushing 1–7 resulted in red shifted fluorescence, which was reversed to its initial state by heating/solvent vapour exposure. Interestingly, integration of 1–7 into a hydrophobic PMMA polymer resulted in blue shifted fluorescence at 470 nm, whereas that into hydrophilic PVA polymer resulted in red shifted fluorescence at 491 nm. Thus highly solid state emissive TPE fused imidazole compounds were prepared, and their stimuli-induced reversible fluorescence switching and polymer controlled tunable fluorescence were demonstrated. [ABSTRACT FROM AUTHOR]

A new intramolecular charge transfer (ICT) based fluorescent turn-on ratiometric probe 2(D–π–A type) has been designed and synthesized by bridging imidazole (donor, D) and benzothiazole (acceptor, A) moieties through a phenyl ring. The photophysical behavior of probe 2in solvents of different polarities and at different pH values has been investigated. Upon interaction with different types of anions probe 2showed selective high affinity for fluoride anions (F−) in aqueous DMSO (20%) solution. The ratiometric fluorescence turn-on behavior displayed by 2with F−is attributed to changes in the ICT process. Job's plot analysis revealed a 1 : 1 binding stoichiometry for 2+ F−interactions with a high binding constant and detection sensitivity (30 ppb). Moreover, a solution of 2+ F−enabled the detection of CO2(∼100 ppb; 2.29 μM) through enhanced emission. The mode of interaction has been confirmed by 1H NMR titration studies which suggested the deprotonation of the –NH fragment of an imidazolyl unit in the presence of F−. [ABSTRACT FROM AUTHOR]

Zeolitic imidazolate frameworks (ZIFs) have attracted considerable attention for many potential applications because they have a unique porous structure and excellent thermal and chemical stabilities. In recent years, significant efforts have been made to develop different methods for the controllable synthesis of ZIFs with desirable crystal structure and morphologies, and for decreasing the excessive amounts of organic ligands and solvents used in the synthesis process to reduce the costs and environmental impacts. This paper highlights the strategies recently reported, including the controllable synthesis of ZIFs with desirable morphologies and pore structure using a surfactant and a template in aqueous solution, the synthesis of ZIF particles and nanocrystals in base solution, and the dry gel and mechanochemical syntheses of ZIFs with minimal solvent usage. [ABSTRACT FROM AUTHOR]

We present an efficient Ullmann-type synthesis methodology enabling the preparation of imidazolium compounds with an extended aromatic core in three steps. This procedure begins with a microwave-assisted, heterogeneously catalysed cross-coupling reaction in the presence of Cu(ii)-doped NaY zeolite to obtain imidazole-aromatic derivatives directly in good yield. The innovation is that this reaction does not require solvent, ligand or an inert atmosphere. Subsequently, these derivatives have been alkylated with bromoalkanes and the bromide of the imidazolium products exchanged for [BF4]− or [PF6]− anions. We have studied the influence of the methyl group (inductive effect) on the aromatic unit during the coupling reaction as well as its impact on different arrangements in the crystalline state. We have been able to extend this synthesis to ionic liquid crystal compounds which display lamellar self-organization (smectic A). The mesomorphic behavior and phase transition temperatures were investigated by polarizing optical microscopy (POM), differential scanning calorimetry (DSC) and small-angle X-ray scattering (SAXS). [ABSTRACT FROM AUTHOR]

Silver complexes [Ag(4,5-dicyano-1-methylimidazole)2]n[CF3SO3]n (1), [Ag2(4,5-dicyano-1-methylimidazole)2][NO3]2 (2) and [Ag2(4,5-dicyano-1-methylimidazole)2]n[ClO3]2n (3) were synthesized in reactions between 4,5-dicyano-1-methylimidazole and silver salts AgCF3SO3, AgNO3 and AgClO3. The compounds were characterized via crystallographic and spectroscopic methods. Due to the different counter ions there were variations in the ligand coordination modes and, as a consequence, different types of solid state structures were generated. The absorption characteristics were explained by the simulation of the UV-Vis spectra using the TD-DFT method. Additionally, computational studies were performed in order to discover the effect of the counter ions via various weak intra- and intermolecular interactions present in the solid state structures. The nature of the interactions was further investigated by topological charge density analysis using the QTAIM method. [ABSTRACT FROM AUTHOR]

Phenazine fluorophore based imidazole derivatives (S1 and S2) were synthesized and sensor studies were carried out with various cations. Aggregation induced emission (AIE) was observed selectively for Al3+ among other cations under study in case of both sensors. 1H NMR titration supported the aggregation induced emission of S2 with Al3+. ESI mass spectra successfully confirmed the aggregate formation. SEM images clearly showed the aggregation of receptor induced by Al3+ in a flower-like fashion. AIE probe was successfully applied for bio-imaging of RAW264.7 cells. [ABSTRACT FROM AUTHOR]

An efficient and practical aerobic benzylic sp3 C–H oxidation as a key step towards the domino multi-component synthesis of 2,4,5-trisubstituted imidazoles has been reported. This green methodology employs an inexpensive catalytic copper/oxygen system and proceeds under mild reaction conditions. A variety of substituted imidazoles are prepared in moderate to excellent yields from α-methylene ketones using this innovative methodology. [ABSTRACT FROM AUTHOR]

A series of flexibly linked bis-imidazolium salts with alkyl sulfate anions having different chain lengths (10, 12, 14) was designed and prepared starting from 1,1′-(α,̉-alkanediyl)-bisimidazole and alkyl bromides (14 or 16 carbon atoms) followed by metathesis with the corresponding sodium salts. These compounds were investigated because of their liquid crystalline properties using a combination of differential scanning calorimetry (DSC), polarized optical microscopy (POM) and temperature dependent powder X-ray diffraction (XRD). All nine bis-imidazolium compounds with alkyl sulfate anions show liquid crystalline properties which were influenced by flexible spacer length, alkyl tail length and, finally, the length of alkyl chains attached to sulfate groups. Broader mesophase ranges were found for compounds with a shorter spacer (six carbon atoms), about 70 °C. For compounds with a spacer of ten carbon atoms, higher mesophase ranges and clearing temperatures were found for longer alkyl tails (sixteen carbon atoms). Increasing the length of alkyl chains attached to sulfate anions resulted in higher clearing temperatures for compounds with the longer spacer. The variation in the carbon atom number of the alkyl sulfate anion for bis-imidazolium compounds with the shorter spacer has almost no impact on their SmA phase stability. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate phosphorus removal in water by using a polyampholyte obtained by the reaction of methacrylic acid, ethylene glycol diglycidyl ether and imidazole by a one step synthesis, mixed with diatomaceous earth. The material was characterized before and after phosphorus exposure using FT-IR, Raman, and solid state 31P-NMR and 13C-NMR spectroscopy concluding that the charged imidazole units were involved in the interaction between the phosphorus and the polyampholyte and that only the H2PO4− species was adsorbed. The point of zero charge value was 5.09. Concomitantly, the optimal pH for P adsorption was 5.0. As pH was increased, the polymer turned more negative, and the phosphate repulsion diminished the adsorption. In the batch experiments, the adsorption isotherms at pH values 5.0 and 7.0 were studied. The effects of different flow rates, P influent concentration and the interference of nitrate and sulfate in the breakthrough curves were studied. A shorter breakthrough time occurred at a higher flow rate. The q0 values not only increased from lower to higher influent levels but also showed a decrease in the presence of S and N as interferents demonstrating that there was a competition for the adsorption sites between those anions and the phosphate. [ABSTRACT FROM AUTHOR]

Based on a bifunctional 2-(pyridine-2-yl)-1H-4,5-imidazole-dicarboxylic acid ligand, a novel family of lanthanide coordination polymers with formulas [Ln(HPIDC)(C2O4)0.5(H2O)]n (Ln = La, 1; Ce, 2) and [Ln2(HPIDC)(C2O4)2(H2O)3]n·2nH2O (Ln = Pr, 3; Nd, 4; Sm, 5; Eu, 6; Gd, 7; Tb, 8; Dy, 9; Ho, 10; Er, 11), (H3PIDC = 2-(pyridine-2-yl)-1H-imidazole-4,5-dicarboxylic acid & H2C2O4 = oxalic acid) has been prepared under hydro-solvothermal conditions and characterized by single crystal X-ray diffraction, elemental analysis, IR spectroscopy, and thermogravimetric analysis. Notably, the ligands adopt the same μ3-kN,O:kO′,O′′:kO′′′ conformation in all compounds, which brings about two types of isostructural lanthanide coordination polymers. Namely, 1 and 2 crystallize in the monoclinic space group P21/n and are composed of [Ln2(COO)2] dinuclear subunits with networks having the symbol (63·82·10)2(63)2(8). Meanwhile, 3–11 crystallize in the monoclinic space group P21/c and are constructed with tetranuclear [Ln4(COO)4] subunits with networks having the symbol (103)2(104·122)(10)2. The photoluminescence measurement indicates that Eu(iii) and Tb(iii) coordination polymers show very strong reddish-orange and green emission bands with CIE chromaticity coordinates (0.612, 0.325) and (0.284, 0.523) and quantum yields of 54.3% & 34.7%, respectively. The magnetic properties of 3 and 7–11 are investigated, and the results indicate a ferromagnetic interaction between Gd(iii) magnetic centers in complex 7 and antiferromagnetic interactions in other complexes. [ABSTRACT FROM AUTHOR]

The treatment of 1-benzyl-3-phenylthio/selenomethyl-1,3-dihydrobenzoimidazole-2-thione/selenone [L1–L4] with [(η5-Cp*)IrCl(μ-Cl)]2 at 25 °C followed by NH4PF6 results in [(η5-Cp*)Ir(L)Cl][PF6] (1–4 for L = L1 to L4), authenticated with high-resolution mass spectrometry (HR-MS) and multi-nuclei nuclear magnetic resonance (NMR) imaging (1H, 13C{1H} and 77Se{1H}). The structures of 1–4, established with single-crystal X-ray diffraction, reveal a “piano-stool” geometry around the Ir. The Ir–thio/selenoether (Ir–S/Ir–Se) bond distances (Å) are 2.347(18)–2.355(4)/2.4663(12)–2.4663(13) and Ir–thione/selenone (Ir–S/Ir–Se) distances are 2.4146(19)–2.417(2)/2.5141(16)–2.5159(12). The reaction of 1,2-phenylenediamine with benzylic alcohols and furfuryl alcohol under mild and ambient conditions, catalyzed efficiently with complexes 1–4, generates bisimine in situ. Cyclization and rearrangement via 1,3-hydride shift triggered by its electrophilic activation with Ir(iii) species finally results in 1,2-disubstituted benzimidazole. The yield of the heterocycles in this one-pot synthesis is excellent to good. The aldehydes generated in situ by aerial oxidation of alcohols in the presence of 1–4 as catalysts are precursors to the bisimine as the protocols of this heterocycle synthesis carried out in the absence of 1,2-phenylenediamine give them in excellent-to-good yield. The oxidation of alcohols by hydrogen transfer to acetone was catalyzed efficiently with complexes 1–4 and resulted in aldehyde/ketone in excellent-to-good yield. Each catalytic process is marginally more efficient with 1 than its counterparts. [ABSTRACT FROM AUTHOR]

The functionalization of carbazole with a spacer in the C1 position and fluorine in the N1 position in the imidazole phenanthroline based bipolar ligand has been designed, synthesised and utilized to make a Eu(TTA)3Phen-Fl-O-CBZ complex. The absorption spectrum of the ligand shows the expected absorption due to the π–π* transition of the aromatic ring and this was verified by theoretical calculation. The PL emission spectra of the complex clearly indicates that the complete energy transfer occurs from ligand to the Eu(iii) metal ion, and this was confirmed by DFT and TD-DFT calculations. It is found that the spacer molecule can decrease the energy gap of the HOMO–LUMO energy levels (2.6 eV) with respect to the case without a spacer molecule. In addition, an increase in the singlet and triplet energy levels was observed, the consequence of efficient energy transfer from the ligand to the Eu(iii) ion. The complex has also been incorporated into the PMMA matrix and its PL properties analysed. The enhanced quantum efficiency observed by 1% doping with PMMA was found to be 14.2% and improved intensity ratios as well as FWHM were also observed. Electrochemical analysis has also been carried out for a better understanding of the energy levels. These results are indicate that the synthesized complex shows potential. [ABSTRACT FROM AUTHOR]

Two imidazolium-based porous organic polymers (Im-POP-1 and Im-POP-2) were synthesized through the Yamamoto reaction of different molar ratios of 1,3-bis(4-bromophenyl)imidazolium bromide and tetrakis(4-bromophenyl)methane, subsequent anion exchange with HAuCl4 and reduction with NaBH4 produced well-dispersed gold nanoparticles (NPs), Au@Im-POP-1 and Au@Im-POP-2. These NPs possess a small size and narrow size distribution, their application in the reduction of nitroarenes was evaluated, and the reduction process was tracked by 13C NMR experiments for reaction mechanism studies. In comparison with gold NPs supported by a non-ionic analogue from the Yamamoto reaction of tetrakis(4-bromophenyl)methane (Au@POP-TPM), Au@Im-POP-2 exhibits high catalytic activity, good selectivity of aniline and superior recyclability in nitrobenzene reduction. The gold NPs in Au@Im-POP-2 increase slightly after four consecutive reaction runs, while an apparent agglomeration of NPs in Au@POP-TPM was observed after the second run. This research provides a new type of support for the stabilization of gold NPs and for the improvement of catalytic performances. [ABSTRACT FROM AUTHOR]

Sulfonic acid functionalized silica-coated CuFe2O4 magnetic nanoparticles were synthesized and characterized by XRD, TEM, SEM, FTIR, EDX, and VSM analysis. The synthesized nanocrystalline CuFe2O4@SiO2–SO3H was used as catalyst for the synthesis of medicinally relevant 2-pyrazole-3-amino-imidazo-fused polyheterocycles. The catalyst offers several advantages such as non-toxicity, high stability, paramagnetic nature and shortest reaction time. [ABSTRACT FROM AUTHOR]

Efficient blue-emitting isomers of bis(phenanthrimidazolyl)biphenyl derivatives, 4,4′-bis(1-methylnaphthyl-1H-phenanthro[9,10-d]imidazol-2-yl)biphenyl (4,4′-BNPIB), 3,4′-bis(1-methylnaphthyl-1H-phenanthro[9,10-d]imidazole-2-yl)biphenyl (3,4′-BNPIB) and 3,3′-bis(1-methylnaphthyl-1H-phenanthro[9,10-d]-imidazol-2-yl)-biphenyl (3,3′-BNPIB) have been synthesised by tuning the coupling position on the biphenyl from the para- to meta-position. These compounds exhibit excellent thermal properties with a high glass-transition temperature of 152–198 °C and emit intense blue light in solution at ca. 396 nm. Because of changes in the degree of conjugation at the C-2 position in the phenanthrimidazole unit, the emission of 3,4′-BNPIB (413/430 nm) and 3,3′-BNPIB (396/426 nm) is blue-shifted when compared with that of 4,4′-BNPIB (422/450 nm) in both solution and film. The fabricated non-doped devices based on these materials exhibit blue emission at 431 nm (4,4′-BNPIB), 412 nm (3,4′-BNPIB) and 400 nm (3,3′-BNPIB), and 3,4′-BNPIB exhibits efficient performance with a maximum luminance of 39 823 cd m−2, a current efficiency of 8.01 cd A−1, a quantum efficiency of 4.85% and a power efficiency of 7.02 lm W−1. [ABSTRACT FROM AUTHOR]

T3P–DMSO mediated desulfurative cyclization of in situ generated thioamides serves as an efficient and versatile method for the synthesis of imidazo[1,5-a]pyridines and [1,2,4]-triazolo[4,3-a]pyridines with good to excellent yields. Substrates such as 2-methylaminoquinoline and pyrazin-2-yl-methanamine also undergo the corresponding reactions at room temperature. This efficient protocol has several advantages such as mild conditions, short reaction time, operational simplicity and high yields. [ABSTRACT FROM AUTHOR]

Great attention has been paid to the design and synthesis of distinct core/shell heterostructures for high-performance supercapacitors. We have prepared unique heterostructures consisting of polyimidazole-coated copper sulphide over a carbon nanotube network (CuS@CNT) on nickel foam, which was accomplished through a facile and cost-effective solvothermal method combined with a dip coating process. Hexagonal covellite CuS nanoparticles were dispersed on CNTs using a solvothermal method where dimethylformamide and distilled water were used as solvents. The synthesized CuS and CuS@CNT supercapacitor electrode materials were thoroughly characterized. The polymer supported electrode (PIM/CuS@CNT) shows a high areal capacitance of 1.51 F cm−2 at a current density of 1.2 A g−1, which is higher than the CuS@CNT electrode and many other previously reported CuS electrode materials. After 1000 cycles at a high current density of 1.2 A g−1, the retention rate is 92%, indicating good long-term cycling stability. These results indicate that the PIM/CuS@CNT electrode is promising for high-performance supercapacitor applications. [ABSTRACT FROM AUTHOR]

Three novel inorganic–organic hybrid compounds based on different types of isopolymolybdates and CuII(bbx) complexes, namely, [Cu2II(bbx)2(β-Mo8O26)]·2H2O (1), [Cu2II(bbx)4(γ-Mo8O26)] (2) and H2[Cu2I(bbx)2(Mo2O8)] (3) (bbx = 1,3-bis(1-imidazolyl)benzene), have been successfully synthesized by adjusting the pH value under hydrothermal conditions. Compound 1, which was hydrothermally prepared at pH = 3.5, exhibits a unique 3D (2,5,6)-connected net with a (43·64·82·10)2(44·68·83)(4)2 topology, constructed by sexadentate Mo8O26)4− anions coordinated to CuII ions of one-dimensional [CuII(bbx)]n chains. When the pH value was adjusted to 4.5, a structurally different complex 2 was obtained. Compound 2 shows a 3D (2,5)-connected framework with an (86·124)2(8)5 topology, constructed by bidentate γ-(Mo8O26)4− polyanions linking 2D layers composed of [CuII(bbx)2]n. Moreover, when the pH value was adjusted to 7.5, an interesting complex 3 was obtained. Compound 3 shows a 2D (4)-connected framework with a (44·62) topology, constructed by bidentate (Mo2O8)4− polyanions linking [Cu2I(bbx)2]n ladder-like double-chains. The (Mo2O8)4− unit has never been observed before, which is composed of two rare distorted {MoO5} tetragonal pyramids connected via edge-sharing. All compounds were characterized by elemental analysis, TG analysis, powder X-ray diffraction, single-crystal X-ray diffraction analysis and solid diffuse reflectance spectroscopy. In addition, the electrochemical properties of compounds 1–3 have been investigated in 1 M H2SO4 aqueous solution. Moreover, compounds 1 and 3 have definite catalytic activities to activate peroxymonosulfate (PMS) in the reduction of methylene blue (MB). [ABSTRACT FROM AUTHOR]

Rhenium(i) N-heterocyclic carbene (NHC) complexes of the type fac-[Re(CO)3(NHC)L] with either azide or triazolate ancillary ligands L and pyridyl or pyrimidyl substituted imidazolyl units have been prepared and structurally characterised, and their photophysical and photochemical properties studied. All of the complexes exhibit phosphorescent emission from triplet metal-to-ligand (3MCLT) excited states, typical of tricarbonyl Re(i) complexes, with the triazolate bound complexes having higher quantum yields and longer decay lifetimes compared to the azide bound complexes. The complexes containing pyridyl substituted imidazolyl units are photoreactive when dissolved in acetonitrile and undergo photochemical CO dissociation, the rate of which is significantly greater in the azide cf. triazolate complex. The photochemical mechanism of the azide/pyridyl complex was analysed and appears to give the same products, albeit with different ratios, to previously reported complexes where L is a halide. A reaction mechanism is proposed. [ABSTRACT FROM AUTHOR]

Starting from the proligand 2-[(6-methylpyridin-2-yl)]imidazo[1,5-a]pyridin-4-ylium hexafluorophosphate(1·PF6), three new complexes, viz. [Au(1)2] [PF6] (2), [1/2AuCl2, 1/2AuCl4]− [(1H)]+ (3), and [Au(1)Cl3] (4), have been synthesized and characterized employing different spectroscopic methods. [Au(1)Cl3] (4) has been synthesized by the disproportionation process. During the transformation of 2 to 4, the annelated proligand stabilizes both Au(i) and Au(iii), and the isolation of the intermediate (3) confirms the conversion of Au(i) → Au(iii) through the disproportionation pathway. The solid state structures of 2, 3 and 4 have been determined. Linear geometry was observed in 2, whereas complex 4 adopted square-planar geometry. Gold complexes 2 and 4 have been subjected to growth inhibitory studies. Complex 2 induced apoptosis in HepG2 cells along with increased expression of proteins involved in the mitochondrial death pathway, suggesting that apoptosis may occur via the mitochondrial death pathway. [ABSTRACT FROM AUTHOR]

The synthesis of microporous aluminophosphates using 1,2,3-trimethylimidazolium (123TMI) and fluoride produces three phases (HPM-3, PST-27 and triclinic AlPO4-34) depending on the amount of water and organic structure-directing agents in the synthesis mixture. Fluoride occluded in double 4-ring units was not detected by 19F MAS NMR spectroscopy in any product. While the structure of HPM-3 remains unknown, PST-27 has been determined to be a monoclinic version of AlPO4-5 with a distorted and likely complex structure. Rietveld analysis using synchrotron diffraction data for as-made triclinic AlPO4-34 reveals that each of its cha-cages holds two 123TMI cations, forming a displaced anti-parallel dimer with a short distance between aromatic rings (3.78 Å from center to center, 3.63 Å from plane to plane). This suggests that π–π interactions may play a role in the synthesis of this phase and related CHA-type systems. A study of the optical properties of PST-27, AlPO4-34 and other materials containing 123TMI cations shows their complex fluorescence behavior, sometimes displaying a red-edge effect, i.e., a red shift of the fluorescence as the excitation wavelength is shifted toward the red edge of the absorption band. An absorption band at 291 nm appears only in the dimer-containing triclinic AlPO4-34 and is sensitive to the introduction of Si into the framework. [ABSTRACT FROM AUTHOR]

Four novel Co(ii) coordination polymers (CPs) based on a “V”-shaped 1,3-di(4′-carboxyl-phenyl)benzene acid (H2dpb), namely {[Co2(dpb)2(4,4′-bibp)2]·2(CH3CN)}n (1), [Co(Hdpb)2(4,4′-bibp)]n (2), {[Co2(dpb)2(tib)2]·H2O}n (3) and {[Co(dpb)(bimb)0.5]·DMF·0.5(CH3CN)}n (4) (4,4′-bibp = 4,4′-bis(imidazol-1-yl)biphenyl, tib = 1,3,5-tris(1-imidazolyl)benzene and bimb = 1,4-bis(imidazol-1-ylmethyl)benzene), have been hydrothermally synthesized and characterized by elemental analysis, IR spectroscopy, powder X-ray diffraction (PXRD), thermogravimetric (TG) analysis and single-crystal X-ray diffraction. Single-crystal X-ray diffraction analysis reveals that complex 1 possesses a uninodal 4-connected 3D (three-dimensional) cds topology framework with the Schläfli symbol (65·8). Complex 2 shows 1D zigzag chains, which are further assembled into a 3D supramolecular structure by O–H…O hydrogen bonds. Complex 3 shows an unprecedented 3-nodal (3,4,6)-connected 3D framework with the Schläfli symbol (62·7)2(64·75·84·9·10)(64·82), while complex 4 displays a {Co2(COO)4} binuclear SBU-based 3D 6-connected (44·611)-unprecedented framework. Moreover, the photocatalytic degradation of the four Co(ii) compounds (complexes 1–4) has been investigated. [ABSTRACT FROM AUTHOR]

Inclusion compounds that contain dynamic polar guests possess rich electrical properties such as ferroelectricity and switchable dielectric constant upon undergoing order–disorder-type phase transitions. We here report a thiourea-based inclusion compound (Him)[(TU)2Cl] (Him = imidazolium, TU = thiourea) that undergoes two reversible structural phase transitions at 139 K and 145 K, which are induced by the order–disorder transformations of the Him cation guests in the channels formed by the anionic [(TU)2Cl] components. Switching of the dielectric constant is thus triggered between the low- and high-dielectric states. [ABSTRACT FROM AUTHOR]

We designed highly active and practical bis(imidazole)/zinc complexes for transesterification reactions. X-ray crystallographic analysis was used to confirm the structures of the zinc complexes and an equivalent of bis(imidazole) ligand was crucial for high catalytic activity. The octahedral zinc complex 8c was prepared in up to a multigram scale by mixing Zn(OCOCF3)2·xH2O and meta-bis(imidazolylmethyl)benzene ligand 7j (two equivalents per zinc ion) and storable under air at room temperature for at least 9 months. The stable nature of the catalyst was amenable to recovery/reuse at least five times without a significant loss of reactivity. The transesterification reaction proceeded without strict reaction conditions, and expanded substrate generalities, including sterically demanding secondary and tertiary alcohols, were applicable. Remarkably, the present zinc catalyst proved highly effective for valuable monomer synthesis from readily available methyl acrylate derivatives. Chemoselective transesterification reactions of unprotected-amino alcohols were also achieved, using not only a simple methyl ester but also an unprecedented dimethyl carbonate. [ABSTRACT FROM AUTHOR]

A new approach for the synthesis of novel bis(imidazol-1-yl)vinyl-1,2,4-oxadiazoles has been developed. This method operates in a single step giving the products in good to excellent yields. Antiproliferative efficiency of the synthesized compounds was tested against HCT116 (colon cancer) and A549 (lung cancer) cell lines. Among them, compounds 3m (IC50, 9.7 μM) and 3h (IC50, 20.3 μM) were found to be the best antiproliferative agents. [ABSTRACT FROM AUTHOR]

A new solid-phase microextraction (SPME) fiber coating material, a zeolitic imidazole framework-67 (ZIF-67) templated nanoporous carbon, Co-NPC, was fabricated by one-step direct carbonization of ZIF-67 without using any other carbon precursors. The prepared Co-NPC was then coated onto a functionalized stainless steel wire by a simple physical coating method to prepare SPME fibers. By coupling the Co-NPC coated fiber based SPME with gas chromatography/micro-electron capture detection (GC/μECD), the developed method exhibited low limits of detection (0.07–0.45 ng g−1) and a wide linearity (0.30–50 ng g−1) for the determination of five organochlorine pesticides (OCPs) in vegetable samples. The method was applied to the analysis of cabbage, cucumber and celery cabbage samples, and the recoveries of the analytes were in the range of 87.9–103.9% with the relative standard deviations (RSDs) ranging from 5.1% to 10.4% (n = 5). Single fiber repeatability and fiber-to-fiber reproducibility values expressed as RSDs were in the range of 4.9–9.6% and 5.8–11.0%, respectively. The method was simple, convenient and feasible for the determination of OCPs in real samples. [ABSTRACT FROM AUTHOR]

A heterogeneous recoverable catalyst was prepared via the complexation of palladium onto the surface of magnetic nanoparticles coated by a poly(1-vinyl imidazole) brush. The stable, active and reusable catalyst was proven to be highly active in aerobic oxidation of primary and secondary alcohols with excellent yields. Only 0.1 mol% of the catalyst was used to oxidize 1 mmol of primary and secondary alcohols. The catalyst was readily recovered and reused up to 10 times under the described reaction conditions without significant loss of activity. [ABSTRACT FROM AUTHOR]

A series of dinuclear [(bpy)2Ru(L)Ru(bpy)2]4+ and mononuclear ruthenium(ii) complexes [(bpy)2Ru(L)]2+ where bpy is 2,2′-bipyridine and L represents 2,6-di(1H-imidazo[4,5-f][1,10]phenanthrolin-2-yl)aryl ligands (DIP) were synthetized and characterized. An original pathway is proposed to obtain mono and hetero bi- and polymetallic Ru complexes and the relation between the molecular structure, the photophysical and electrochemical properties of the single Ru complexes is analysed. The investigated aryl cores are benzene, pyridine and 4-tert-butyl phenol. This work is focused on the effect of the aromatic moiety on the photoinduced charge transfer in the bimetallic compounds and the results are compared with the monometallic analogues. The absence of effect on the UV-visible absorption spectra and on the redox behavior upon varying the nature of the aryl moiety show that the two metallic centres in [(bpy)2Ru(L)Ru(bpy)2]4+ complexes are independent. However, luminescence measurements coupled with DFT calculations highlight a different photophysical behaviour between mono and dinuclear compounds incorporating the benzene core. Theoretical DFT and TD-DFT modelling was used to support the studied physico-chemical properties of these molecular systems. [ABSTRACT FROM AUTHOR]

Novel multi-SO3H functionalized strong Brønsted acidic ionic liquid coated magnetite nanoparticles have been prepared and applied as catalyst for the synthesis of 2,4,5-trisubstituted imidazoles. The results showed that a novel catalyst was very efficient for the reaction and could be magnetically separated and reused at least 6 times with less reduction in its catalytic activity. Operational simplicity, low cost of the catalyst used, high yields, environmental friendliness, wide applicability, reusability and easy recovery of the catalyst using an external magnet are the most important features of this methodology. The catalyst was characterized by Fourier transform infrared spectroscopy (FT-IR), X-Ray diffraction analysis (XRD), field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray analysis (EDX), dynamic laser scattering (DLS) and vibrating sample magnetometry (VSM). [ABSTRACT FROM AUTHOR]

An imidazole-based zwitterionic-salt, 4-(3-methylimidazolium)butane sulfonate (MBS), has been found to be an efficient organocatalyst for aziridine ring-opening regioselectively by various nucleophiles like indoles, pyrroles, methanol, ethanol, acetic acid and di-iso-propylamine. The reactions are highly regioselective and they always afford the products resulting from benzylic attack. The present methodology is applicable to gram scale synthesis. [ABSTRACT FROM AUTHOR]

Two adamantane-bridged tripodal trisimidazolium or trisbenzimidazolium salts were designed as C3v-symmetrical tricarbene ligands and synthesized in good yields. The reaction of the tripodal trisazolium salt precursors with silver oxide provided trisilver hexacarbene complexes bearing a three-dimensional framework. Multinuclear NMR spectroscopy and mass spectrometry data showed that the complexes were symmetric structures of two tricarbene ligands, three metal ions, and three counter anions. X-ray crystallographic analyses revealed that both complex cations adopted a highly twisted conformation. The complex cations built from the trisimidazolium salts were arranged into columnar structures through CH/π interactions, which were assembled into a three-dimensional network structure by intermolecular CH/F interactions via hexafluorophosphate anions. The complex cations generated from the trisbenzimidazolium salts were aligned into columnar structures, which were arranged into a network structure through CH/π interactions. Solvents and counter anions were accommodated in the spaces of the crystalline lattices. [ABSTRACT FROM AUTHOR]

Coralloid Fe3O4 nanoclusters stacked by nanosheets are successfully synthesized using ferric nitrate as a precursor with an ionic liquid-assisted solvothermal method. For comparison, spherical Fe3O4 nanoclusters assembled by nanospheres are synthesized in the absence of ILs. The morphologies and structures of the products are further characterized by field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray power diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The results indicate that the ionic liquid 1-n-decyl-3-methylimidazolium chloride ([Dmim]Cl) plays an important role in controlling the growth orientation of building blocks via selectively adsorbing on a specific crystal plane. A formation mechanism has been proposed based on the interaction between ILs and Fe3O4 crystal planes. The catalytic activity of nanoclusters has been evaluated with the Fenton reaction under UVA irradiation. The coralloid nanoclusters show the highest catalytic activity for the degradation of phenol due to their special morphology and unique surface properties. The synthesis strategy may provide a new way to construct nanomaterials with novel morphologies and excellent properties. [ABSTRACT FROM AUTHOR]

Water-soluble silver(i) complexes containing the 4(5)-(hydroxymethyl)imidazole ligand with the formula [Ag(4-CH2OHimH)2]X (where X = NO3−, ClO4−, CF3COO−, BF4−and SO3CH3−) were synthesized. The complexes were characterized by NMR (1H and 13C) and IR spectroscopy, ESI-MS spectrometry and EA. The molecular structures of three complexes were confirmed by X-ray crystallography. The antimicrobial activity of the silver(i) complexes were evaluated against six strains of microorganisms: Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Pseudomonas aeruginosa, Proteus hauseriand Candida albicans. All tested silver complexes displayed excellent antibacterial properties against Gram-positive bacteria. Among them, the complex containing the trifluoroacetate counter-ion exhibited the highest antibacterial activity, with MIC values 2 to 3-fold lower than that required by silver sulfadiazine. [ABSTRACT FROM AUTHOR]

Two ionic (1aand 1b) and two neutral (2aand 2b) Cu(i) complexes containing an un-deprotonated or a deprotonated nitrogen ligand {2-(4-methyl phenyl) imidazole[4,5-f]-1,10-phenanthroline, MHPIP} and different phosphine ligands (bis[2-(diphenylphosphino) phenyl]ether and PPh3) have been synthesized and characterized by elemental analysis, 1H NMR spectroscopy and X-ray crystallography (1b, 2aand 2b). The complexes adopt a distorted tetrahedral geometry constructed by MHPIP (or MPIP−) and phosphine ligands. The emission spectra show that the ionic complexes exhibit almost ignorable luminescence. However, the deprotonation of the nitrogen ligand makes the neutral complexes exhibit orange or yellow emission both in solution and solid-powder states. Considering the different luminous characters of the neutral complexes, density functional theory (DFT) calculations have been performed at the B3LYP/6-31G** level to provide information about the impact of phosphine ligands on the frontier orbital. [ABSTRACT FROM AUTHOR]

Vinyl imidazole functionalized ordered mesoporous silica (SBA/VI) were synthesized by in situradical polymerization of vinyl imidazole monomers and characterized for antibacterial activity against Gram positive and Gram negative bacteria. The results showed an increasing trend with the concentration of vinyl imidazole(vi) and maximum antibacterial activity could be achieved with SBA/VI55nanocomposites. The possible explanation for higher antibacterial activity is also explained. [ABSTRACT FROM AUTHOR]

Five coordination polymers (CPs) with distinct structures, namely, [Cu(H2tptc)(1,4-bidb)]n (1), {[Co2(tptc)(1,3,5-tib)(H2O)]·7H2O}n (2), {[Ni(tptc)0.5(1,3-bimb)]·H2O}n (3), {[Zn(qptc)0.5(1,4-bimb)]·3H2O}n (4), and {[Zn(qptc)0.5(1,3-bimb)]·H2O}n (5) (H4tptc = terphenyl-3,3′′,5,5′′-tetracarboxylic acid, H4qptc = quaterphenyl-3,3′′′,5,5′′′-tetracarboxylic acid, 1,4-bidb = 1,4-bis(1-imidazol-yl)-2,5-dimethyl benzene, 1,3,5-tib = 1,3,5-tris(1-imidazol-yl)benzene, 1,3-bimb = 1,3-bis(imidazol-1-ylmethyl)benzene, and 1,4-bimb = 1,4-bis(imidazol-1-ylmethyl)benzene), have been synthesized through a mixed ligand strategy. Complex 1 features a new 3D (4,6)-connected net with a Schläfli symbol of (42·64)(42·68·7·84). Complex 2 displays a 3D 2-fold interpenetrated framework with an unprecedented (3,3,4,4)-connected (6·82)2(62·83·10)(62·84) topology. Complex 3 exhibits a (32·62·72)-kgm layer featuring a 2D + 2D → 3D packing supramolecular structure interweaved through [Ni(1,3-bimb)] lock knots. Complex 4 shows an unprecedented 3D (4,4)-connected 86 net. Complex 5 is also a 2D + 2D → 3D supramolecular structure featuring kgm sheets hinged together through [Zn(1,3-bimb)] lock knots. In addition, the luminescence properties of 4 and 5 have been investigated. Moreover, complexes 1–3 show relatively good photocatalytic activities for methylene blue (MB) dye degradation in aqueous solution under UV light. [ABSTRACT FROM AUTHOR]

A simple, highly versatile and efficient synthesis of 2,4,5-trisubstituted imidazoles is achieved through a three component one pot reaction of benzil, benzaldehyde and NH4OAc. This reaction has been catalyzed by Fe3O4@SiO2·HM·SO3H, a very efficient, novel recyclable heterogeneous catalyst, under microwave irradiation and solvent free conditions. The catalyst can be recovered for the subsequent reactions and reused for at least five rounds, without any appreciable loss of its efficiency. [ABSTRACT FROM AUTHOR]

In 2009, we reported the first example of the optical resolution of a five-coordinate complex. In this study, we discuss the chirality of five-coordinate enantiomers displaying mono- and bi-dentate ligands by optical resolution of three complexes. Through total spontaneous resolution, it was possible to obtain optically active bulk products starting from achiral precursors only. It was discovered that crystallisation of two of the complexes was influenced by undetectable amounts of an unidentified source of optical activity. [ABSTRACT FROM AUTHOR]

Reactions of divalent transition metal ions with the N,N′-sulfuryldiimidazole ligand (sdi) gave rise to eleven coordination polymers, namely, [Zn(sdi)(NO3)2(H2O)] (1), [Zn(sdi)2(NO3)2] (2), [Co(sdi)2(NO3)2] (3), [Cu(sdi)2(NO3)2]·2CO(CH3)2 (4), [Mn(sdi)2(H2O)2]·2NO3 (5), [Co(sdi)2(H2O)2]·2ClO4 (6), [Zn(sdi)(bdc)0.5(OCH3)(H2O)]·ClO4·H2O (7), [Cd(sdi)(N3)2] (8), [Mn(sdi)(N3)2] (9), [Ni(sdi)2(SO4)] (10) and [Cd(sdi)0.5(Hbtc)(OCH3)] (11) (H2bdc = 1,4-benzenedicarboxylic acid, H3btc = 1,3,5-benzenetricarboxylic acid). X-ray single-crystal analyses reveal that they have rich structural chemistry ranging from zero-dimensional (0D) (1), one-dimensional (1D) (2–7), two-dimensional (2D) (8) to three-dimensional (3D) (9–11) networks. Compound 1 displays a 0D structure which consists of [Zn(sdi)]2 dimers. Compounds 2–7 possess 1D chains with closed loops. Compound 8 shows a 2D (63) network. Compounds 9 and 10 exhibit 3D uninodal 6-connected pcu frameworks with (412·63) topology. Compound 11 displays a 3D uninodal 4-connected framework with a CdSO4-like net (65·8). The effects of metal ions and anions on the final motifs of the compounds have been discussed in detail. All the compounds are characterized using powder X-ray diffraction (PXRD), IR spectroscopy, thermal stability analysis and elemental analyses. Moreover, the photoluminescence properties of 1, 2, 7, 8 and 11 have been investigated. Magnetic investigation of 9 reveals spin canting antiferromagnetic interactions. [ABSTRACT FROM AUTHOR]

New hybrid organic–inorganic boron compounds using an imidazole core have been readily synthesized by a two-step procedure from commercially available simple starting materials. All boron compounds were fully characterized by multinuclear NMR spectroscopy, LC-MS, thermogravimetric analysis, cyclic voltammetry and single crystal X-ray diffraction analysis (for 2a & 2c). The photoluminescence measurements of 2a–2c revealed distinct emission peak maxima located at 378, 379 and 387 nm, respectively. Electroluminescent devices fabricated using these boron compounds (2a–2c) suggest that the boron compounds are capable of transporting electrons. A maximum brightness of 6450 cd m−2 at 12.5 V was realized when compound 2a was used as an electron-transporting material. [ABSTRACT FROM AUTHOR]

The solvent free reaction of Zn(OAc)2 with an imidazole ligand resulted in a 1-dimensional (1D) chain structure with the formula [Zn(Im)(HIm)2(OAc)] (Im = imidazolate, HIm = imidazole, OAc = carboxylate) (1). The results by kinetic experiments suggest that (1) likely evolves from an unidentified metastable phase. This new 1D chain precursor (1) is a quaternary system comprising Zn, Im, OAc and HIm. We have used this 1D compound as a single precursor to prepare 3-dimensional (3D) Zn(Im)2 frameworks. Specifically, two Zn(Im)2 frameworks with known zni and coi topologies were prepared via thermal-mediated transformation when heated in an open atmosphere and in a closed vessel, respectively. In an open atmosphere, the kinetic experiments confirmed the rapid phase transformation from (1) to zni without formation of an intermediate phase. In contrast, in the formation process of coi in a closed vessel, phase transformation from (1) to zni and immediately from zni to coi was observed. Thus, in a closed vessel, the released molecules, HOAc and HIm, were occluded in the framework, which may together exert a cooperative structure-directing effect on the formation of the coi framework. Thus, a single precursor approach was established for the synthesis of ZIFs. The present work represents the first example of transforming a 1D coordination polymer into 3D ZIF framework structures. [ABSTRACT FROM AUTHOR]

The reaction of the N-heterocyclic carbene 1,3-di-tert-butyl-4,5-dimethylimidazolin-2-ylidene (1b) with trimethylsilyl iodide, triflate and triflimidate [Me3SiX, X = I, CF3SO3 (OTf), (CF3SO2)2N (NTf2)] by mixing the neat, liquid starting materials afforded the corresponding 2-(trimethylsilyl)imidazolium salts [(1b)SiMe3]X as highly reactive, white crystalline solids. Only the triflimidate (X = NTf2) proved to be stable in solution and could be characterized by means of NMR spectroscopy (in C6D5Br) and X-ray diffraction analysis, whereas dissociation into free 1b and Me3SiOTf was observed for the triflate system, in agreement with the trend derived by DFT calculations; the iodide was too insoluble for characterization. The compounds [(1b)SiMe3]X showed the reactivity expected for frustrated carbene–silylium pairs, and treatment with carbon dioxide, tert-butyl isocyanate and diphenylbutadiyne gave the 1,2-addition products [(1b)CO2SiMe3]X (X = I, OTf, NTf2), [(1b)C(NtBu)OSiMe3]OTf and [(1b)C(Ph)C(SiMe3)CCPh]OTf, respectively. Upon reaction with [AuCl(PPh3)], metal–chloride bond activation was observed, with formation of the cationic gold(i) complexes [(1b)Au(PPh3)]X (X = OTf, NTf2). [ABSTRACT FROM AUTHOR]

Three five-coordinate, high spin manganese(ii) “picket fence” porphyrin complexes, [Mn(TpivPP)(L)] (TpivPP = α,α,α,α-tetrakis(o-pivalamidophenyl)porphyrinato; L = 1-MeIm (1-methylimidazole), 1-EtIm (1-ethylimidazole) and 2-MeHIm (2-methylimidazole)), are synthesized and studied by single-crystal X-ray, UV-vis and electronic paramagnetic resonance (EPR) spectroscopy. Structural parameters are investigated and compared with analogues. Low temperature (90 K), high field EPR studies of [Mn(TpivPP)(1-MeIm)] and [Mn(TpivPP)(2-MeHIm)] showed five resonances including characteristic signals at ∼5.9 and ∼2.0. The simulations of the EPR spectra give the zero field splitting (zfs) parameters (D, E and λ) and the hyperfine coupling constant (A). [ABSTRACT FROM AUTHOR]

Two N-heterocyclic carbene precursors having their nitrogen atoms substituted by the expanded 9-ethyl-9-fluorenyl group, namely imidazolinium chloride 6 and imidazolium chloride 7, have been synthesized in high yields from fluorenone (1). The key intermediate of their syntheses is the new primary amine 9-ethyl-9-fluorenylamine (3), which was prepared in 75% yield. Both salts were readily converted into the corresponding PEPPSI-type palladium complexes, 8 and 9 (PEPPSI: pyridine-enhanced precatalyst preparation stabilisation and initiation). Despite rotational freedom of the ethylfluorenyl moieties about the N–C(fluorenyl) bond in their cationic precursors, the carbene ligands of the Pd(ii)-complexes 8 and 9 both behave as bimodal pincers in solution and in the solid state, the resulting confinement being essentially due to (weak) attractive anagostic interactions between the CH2(fluorenyl) groups and the metal centre. Unlike in 8 and 9, there was no indication for similar anagostic interactions in the imidazolylidene chlorosilver complex 11, which could be obtained from 7. In the solid state, however, 11 adopts a remarkable “open sandwich” structure, with the two alkylfluorenilidene planes η2-bonded to the silver, this constituting a further bimodal pincer-type bonding mode of this ligand class. Complexes 8 and 9 were assessed in Suzuki–Miyaura cross-coupling reactions. The imidazolylidene complex 9 displayed high activity towards unencumbered aryl chlorides. Its activity is comparable to that of the previously reported, highly efficient benzimidazolylidene analogue 10. [ABSTRACT FROM AUTHOR]

The unique properties of metal–organic frameworks, such as diversity in structures and pore sizes, high surface area, shape selectivity and available to functionality make them as potential materials of the stationary phase for gas chromatography. Here we show an in situ growth approach to the fabrication of zeolite imidazolate framework-90 (ZIF-90) bonded capillary column for gas chromatography separation. ZIF-90 was directly grown onto the inner wall of the carboxyl modified capillary via the coordination between Zn(ii) and carboxyl group. The fabricated ZIF-90 bonded capillary column acted as a weak polar stationary phase. It not only exhibits high capacity in the separation of linear molecules, but also offers excellent features for the separation of 2- and 3-substituted ketones. [ABSTRACT FROM AUTHOR]

An efficient, green and ecofriendly procedure has been developed using Fe3O4@SiO2–imid–PMAn as a magnetic catalyst for a rapid and improved synthesis of 2,4,5-trisubstituted and 1,2,4,5-tetrasubstituted imidazoles under solvent-free conditions and microwave irradiation in excellent yields. The reactions under conventional heating conditions were compared with the microwave-assisted reactions. The operational simplicity, practicability and applicability of this protocol to various substrates make it an interesting alternative to previous procedures. The present approach offers several advantages such as short reaction times, high yields, simplicity of operation, easy work-up, a cleaner reaction and ease of recovery and reusability of the catalyst using a magnetic field. Also, the nanocatalyst can be easily recovered by the application of a magnetic field and reused for the next reactions at least 5 times without distinct deterioration in catalytic activity. SEM, BET, DLS and leaching of the catalyst after each reaction cycle were investigated. [ABSTRACT FROM AUTHOR]

Presented are the syntheses, characterizations and properties of a series of selenidostannate compounds directed by metal–amine complex (MAC) cations and/or [Bmmim]+ (Bmmim = 1-butyl-2,3-dimethylimidazolium). Mixtures of the ionic liquid (IL) (Bmmim)Cl and amines, such as ethylenediamine (en) and diethylenetriamine (dien), in various ratios were used to ionothermally/solvothermally prepare four selenidostannates, namely, [Mn(en)3]Sn3Se7 (1), [Mn(dien)2]Sn3Se7·H2O (2), (Bmmim)3[Mn(en)3]2[Sn9Se21]Cl (3) and (Bmmim)6[Mn(dien)2]2Sn15Se35 (4). Single-crystal X-ray diffraction analyses revealed that these compounds exhibit lamellar anionic [Sn3Se7]n2n− structures. [Sn3Se7]n2n− layers in all 1–4 possess a {63} net, considering [Sn3Se10] semi-cube unit as a 3-connected node; however, diverse multi-membered rings exist there. In compounds 1 and 2, all the [Sn3Se10] units are 3-connected nodes interlinking with each other via edge-sharing two Se atoms to produce six-membered rings. However, in compound 3, the insertion of two [Sn3Se9] units into a six-membered ring results in a novel eight-membered heart-shaped ring, which has never been observed before in the family of chalcogenidostannates. More interestingly, the [Sn3Se7]n2n− layer in compound 4 consists of mixed six- and eight-membered rings. The phase composition is strongly dependent on the ratio of IL to MAC in the syntheses, e.g., 1 and 2 were obtained with IL : MAC ratios less than 3 : 1 and 4 : 1, while 3 and 4 were obtained when the ratios were increased to 4 : 1 and 5 : 1, respectively. The structural variation from 1 to 4 clearly indicates the competitive and synergistic effects between MAC and IL cation on the formation of lamellar selenidostannates. A synthetic approach via varying the ratio of IL to MAC cation as solvent and structure-directing agent will be attractive in the synthesis of novel chalcogenidometallates. [ABSTRACT FROM AUTHOR]

Despite the popularity and versatility of transition-metal–azolium carboxylate coordination polymers, there are very few examples of group 2 complexes supported by azolium carboxylate ligands in the literature, and there are none featuring luminescent calcium azolium carboxylates. New ionic calcium coordination networks, {[Ca2(L1)2(H2O)4](Br)4·6H2O}∞ (1), {[(L3)2Ca(H2O)2]2(Br)2}∞ (3), {[(L4)2Ca(H2O)2]2(Br)2}∞ (4), and {[(L5)2Ca3(Na)(H2O)9(Cl)](Br)6·2H2O}∞ (5) along with binuclear {[Ca2(L2)2(H2O)9](Br)4·4H2O} (2), and trinuclear {[(L6)2Ca3(H2O)9](Br)6} (6) were isolated from the reaction between the corresponding azolium carboxylates and calcium carbonate in aqueous solution. 1–6 were characterized by FT-IR, NMR, TGA, UV-vis, fluorescence and single crystal X-ray diffraction techniques. Interestingly, the first tetra-cationic binuclear calcium 2 was isolated using L2H2Br2 and hexa-cationic trinuclear calcium 6 was isolated using L6H3Br3. The 3D coordination polymers 1 and 4 were derived with the help of L1H2Br2 and L4H2Br2, respectively, through Br…H hydrogen bonding. The 3D MOF 3 with rhomboidal channels was constructed using L3H2Br2, where the channel size is about 4.8 × 2.9 nm. 5 was isolated as a rare 1D coordination polymer. The choice of azolium carboxylates in these solids not only changes the topology of the network but also affects the chemistry exhibited by the network. Calcium azolium carboxylate assemblies 1–4 and 6 exhibit interesting solid-state photoluminescence properties, driven by azolium carboxylate ligands. Variation of the bridging chromophore produced significant effects on the fluorescence properties. 1–4 and 6 represent the first examples of luminescent calcium azolium carboxylate complexes. As can be seen in the six metal–organic assemblies presented in this report, a combination of carboxylate groups and steric hindrance affects the topology and physical properties of the resultant solids. [ABSTRACT FROM AUTHOR]

In the series of homo-leptic trinuclear complexes {[Ln3(L)4Cl4(MeOH)(H2O)]·Cl} (Ln = La, 1; Ln = Eu, 2; Ln = Tb, 3 or Ln = Gd, 4) self-assembled from the allyl-modified benzimidazole-type ligand HL (4-allyl-2-(1H-benzo[d]imidazol-2-yl)-6-methoxyphenol) and LnCl3·6H2O, a suitable energy level match endows efficient green luminescence (Φoverall = 72%) of Tb3-arrayed complex 3. The copolymerization between each of these complex monomers 1–4 and C=C-containing MMA (methyl methacrylate) or NBE (norbornene) shows that degradative chain transfer of the terminal four flexible allyl groups within restrains their radical polymerization with MMA while it does not hinder their effective ring-opening metathesis polymerization (ROMP) with NBE. Thus, two kinds of PMMA-supported doping hybrid materials 1@PMMA, 2@PMMA, 3@PMMA and 4@PMMA and PNBE-supported metallopolymer-type hybrid materials Poly(NBE-1), Poly(NBE-2), Poly(NBE-3) and Poly(NBE-4) are obtained, respectively. Especially for both 3@PMMA and Poly(NBE-3) with high color-purity characteristic green emission of Tb3+ ions, improved physical properties including significantly enhanced luminescence (Φoverall = 76% or 83%) are observed, and covalent-bonding endows a higher-concentration self-quenching as compared to physical doping. [ABSTRACT FROM AUTHOR]