Bim Ligands Research Articles

Ru(II) Complexes with Absorption in the Photodynamic Therapy Window: 1O2 Sensitization, DNA Binding, and Plasmid DNA Photocleavage.

Two Ru(II) complexes, [Ru(pydppn)(bim)(py)]2+ [2; pydppn = 3-(pyrid-2'-yl)-4,5,9,16-tetraaza-dibenzo[a,c]naphthacene; bim = 2,2'-bisimidazole; py = pyridine] and [Ru(pydppn)(Me4bim)(py)]2+ [3; Me4bim = 2,2'-bis(4,5-dimethylimidazole)], were synthesized and characterized, and their photophysical properties, DNA binding, and photocleavage were evaluated and compared to [Ru(pydppn)(bpy)(py)]2+ (1; bpy = 2,2'-bipyridine). Complexes 2 and 3 exhibit broad 1MLCT (metal-to-ligand charge transfer) transitions with maxima at ∼470 nm and shoulders at ∼525 and ∼600 nm that extend to ∼800 nm. These bands are red-shifted relative to those of 1, attributed to the π-donating ability of the bim and Me4bim ligands. A strong signal at 550 nm is observed in the transient absorption spectra of 1-3, previously assigned as arising from a pydppn-centered 3ππ* state, with lifetimes of ∼19 μs for 1 and 2 and ∼270 ns for 3. A number of methods were used to characterize the mode of binding of 1-3 to DNA, including absorption titrations, thermal denaturation, relative viscosity changes, and circular dichroism, all of which point to the intercalation of the pydpppn ligand between the nucleobases. The photocleavage of plasmid pUC19 DNA was observed upon the irradiation of 1-3 with visible and red light, attributed to the sensitized generation of 1O2 by the complexes. These findings indicate that the bim ligand, together with pydppn, serves to shift the absorption of Ru(II) complexes to the photodynamic therapy window, 600-900 nm, and also extend the excited state lifetimes for the efficient production of cytotoxic singlet oxygen.

Electrochemical engineering of ZIF-7 electrode using ion beam technology for better supercapacitor performance

In the study, ZIF-7 material was exposed to 500 keV copper (Cu++) ions at dosages of 1 × 1014, 1 × 1015, and 5 × 1014 ions/cm2. The ZIF-7 unirradiated reveals a polycrystalline with an intense peak at 16.231° with a crystal plane of (012). The intensity of the peak in the XRD pattern broadens as the radiation of copper ions increases. In the ZIF-7 FTIR, the CC stretching vibration of the benzene ring is visible at 1469 cm−1, and the hydroxy phenyl benzimidazole (bIm) ligand's CH bending vibration is visible at 740 cm−1. Irradiated ZIF-7 reveals CH bending at 758, 759, and 754 cm−1 from the bIm ligand and CC stretching at 1456, 1460, and 1457 cm−1. The CV plots showed redox peaks, demonstrating faradaic processes. The ZIF-7's unirradiated estimated specific capacitances at scan rates of 50, 40, 30, 20, and 10 mV/s are 156, 195, 260, 390, and 781 F/g. The estimated specific capacitance of the irradiated ZIF-7 material with copper ions of 1 × 1014 ions/cm2 is 185, 308, 462, and 925 F/g. The estimated specific capacitance for ZIF-7 with copper ions of 1 × 1015 and 5 × 1014 ions/cm2 are 187, 234, 468, 937, and 1200 F/g, and 300, 375, 500, 750, and 1200 F/g respectively. The unirradiated (ZIF-7) shows bandgap energy of 3.53 eV which is suitable for applications in gas separation, catalysis, and optoelectronics. The irradiated sample with 1 × 1014 ions/cm2, 1 × 1015 ions/cm2 and 5 × 1014 ions/cm2 revealed bandgap energy of 2.52 to 2.87 eV which is suitable energy storage application.

Ligand-mediated electrocatalytic activity of Cu-imidazolate coordination polymers for OER in water electrolysis

Copper is an Earth-abundant element promising for the synthesis of robust and efficient oxygen evolution reaction (OER) electrocatalysts. In this study, three Cu-imidazolate coordination polymers (Cu-Im, Cu-mIm, and Cu-bIm) are electrochemically synthesized and examined as OER catalysts whose activity can be modulated by the coordinating ligands of imidazole (Im), 2-methylimidazole (mIm), and benzimidazole (bIm). During the water electrolysis, Cu-Im and Cu-mIm are partially oxidized to form CuO particles, a well-known OER catalyst, while Cu-bIm does not. Due to the in situ formation of CuO during the electrolysis and weaker hydrophobicity of Im ligand, Cu-Im shows the highest electrocatalytic activity with a modest overpotential of 500 mV delivering a current density of 10 mA cm−2 and a Tafel slope of 215 mV dec−1 in 1 M KOH. On the contrary, the hydrophobic and anti-corrosion property of the bIm ligand stabilizes the Cu-bIm during the electrolysis without CuO formation. The hydrophobicity of the coordinating ligand influenced the electrocatalytic activity, resulting in the order of Cu-Im > Cu-mIm > Cu-bIm. Post-reaction analyses of the Cu-imidazolate coordination polymers reveal variations in the oxidation state of Cu, which has not been explored in previous studies. This work underlines that the ligand properties can regulate the catalytic activity of metal-ligand coordination polymer.

Flexibility of Mixed Ligand Zeolitic Imidazolate Frameworks (ZIF-7-8) under CO2 Pressure: An Investigation Using Positron Annihilation Lifetime Spectroscopy.

Fine tuning of the pore architecture and flexibility of zeolitic imidazolate frameworks (ZIFs) is highly crucial for realizing their applications in molecular gas separation. Mixed ligand frameworks (ZIF-7-8) synthesized by mixing 2-methylimidazole (2meIm) and benzimidazole (bIm) ligands show enhanced gas separation performance, attributable to pore and flexibility tuning. In the present study, positron annihilation lifetime spectroscopy (PALS) measurements under CO2 pressure have been used to experimentally investigate the tuning of the pore architecture and flexibility of mixed ligand frameworks ZIF-7-8 having a ZIF-8 structure and similar morphology with varying bIm content up to 18.2%. The aperture and cavity of frameworks begin to open up with an increasing bIm ligand content followed by a decrease at a higher content. On the contrary, flexibility of the frameworks indexed from PALS measurements carried out under CO2 pressure shows a decreasing trend followed by an increase. The present study shows that mixed ligand frameworks having a larger aperture size are less flexible as a result of inherent open configurations of ligands in the framework lattice. On the other hand, frameworks having a comparatively smaller aperture size show higher flexibility as a result of a possibility of twisting of the ligands under CO2 pressure, resulting in aperture opening. The pore-opening phenomenon as a result of lattice flexibility under CO2 pressure is observed to be fully reversible for ZIF-7-8.

Catalytic Enantioselective Construction of 6‐4 Ring‐Junction All‐Carbon Stereocenters and Mechanistic Insights

Comprehensive SummaryDeveloping reactions for the synthesis of 6‐6‐4 and 6‐4 carbocyclic scaffolds with a chiral quaternary center at the bridgehead position is highly desired, considering the existence of such skeletons in natural products with biological activities and the potential of using these molecules for downstream studies in chemical biology and medicinal chemistry. Report here is accessing these target skeletons with high chemo‐, regio‐ and enantio‐selectivities through Pd(II)/chiral N,N’‐disulfonyl bisimidazoline (Bim) ligand‐catalyzed asymmetric reaction of yne‐allenones and arylboronic acids. Realization of 6‐6‐4 skeleton with a ring‐junction all‐carbon stereocenter is a one‐step process while synthesizing 6‐4 skeleton is a two‐step process, which begins with intramolecular [2 + 2] reaction of allenes with alkynes, followed by Pd‐catalyzed asymmetric addition of arylboronic acids to cyclic enones generated in the first step. Noteworthy is that chiral Bim ligand as a C2‐symmetric N,N’‐bidentateanionic ligand, designed by us, in coordinating with Pd catalyst was first applied to catalyze asymmetric 1,4‐conjugate addition reaction with the high catalytic performance (the reaction can be carried out in air). DFT calculations have been applied to understand how these reactions take place, the origins of enantioselectivity, and relative reactivities of different substrates.

Fabrication of 2D bimetallic metal-organic framework ultrathin membranes by vapor phase transformation of hydroxy double salts

At present, the construction of a bimetallic and oriented MOF nanosheet membrane that integrates the advantages of both bimetallic MOF and oriented membranes is highly desirable but also challenging. Herein, we report a vapor phase transformation (VPT) strategy for directly growing a highly oriented bimetallic (Zn/Co) 2 (bIm) 4 (bIm = benzimidazole) nanosheet membrane, based on the conversion of hydroxy double salts (HDS) under bIm ligand vapor treatment. The fabricated strategy includes first the growth of a layer of bimetallic Zn/Co-HDS on a porous tube and then the conversion of the HDS layer into a highly oriented bimetallic nanosheet membrane via the VPT strategy. The formation mechanism of the membrane is discussed. The resulting ultrathin nanosheet membrane with the thickness of about 80 nm exhibits excellent gas separation performance with H 2 permeance of 1.68 × 10 -7 mol m -2 s -1 ·Pa -1 and H 2 /CO 2 ideal separation selectivity of 54.1. This approach shows great potential in large-scale fabrication of nanosheet membranes, especially the bimetallic MOF nanosheet membranes. • A VPT strategy is developed for growing bimetallic MOF nanosheet membrane based on the conversion of HDS. • The achieved bimetallic MOF nanosheet membrane combines the advantages of nanosheets and bimetallic MOFs. • Both HDS layer and VPT strategy cooperatively facilitate the generation of bimetallic MOF nanosheet membrane. • The membrane exhibited excellent molecular sieving performance for H 2 /CO 2 .

Fine tuning of pore architecture and morphology of stiffened Zeolitic Imidazolate Frameworks synthesized using fast current driven method and mixed ligand strategy

Zeolitic Imidazolate Frameworks (ZIFs) show great promise in molecular separation as well as recognition owing to their crystalline morphology consisting of a well designed pore architecture. However, the sieving performance of ZIFs remains limited due to their fixed pore sizes and framework flexibility. In the present study, fast current driven synthesis (FCDS) has been used to prepare the stiffened phase of mixed ligands (2-methylimidazole and benzimidazole) based ZIFs having tunable pore sizes and morphologies. X-ray diffraction has been used to determine the crystal structure of the frameworks, which were observed to be crystalline through a wide range of ligand ratio (benzimidazole fraction: ∼0.206–0.972). The random distribution of both the ligands in the frameworks has been established through complementary methods viz. Raman spectroscopy, Fourier transform infrared and scanning electron microscopy. Morphology of the frameworks was observed to vary from micrometer size individual crystals to spherical aggregates of inter-grown nanocrystals to individual nanocrystals. Pore sizes determined using positronium lifetime measurements were observed to be consistent with the literature for pure phase of ZIF-7 and stiffened ZIF-8. The pore sizes were observed to vary with the benzimidazole ligand fraction confirming that mixed ligand strategy can be used to efficiently tune the pore sizes of the frameworks. Positronium diffusion investigation confirms that pore interconnectivity is inferior as compared to stiffened ZIF-8 but superior than ZIF-7 in these mixed ligand frameworks. • Twelve stiffened ZIF-7 x -8 ( x = 0–1) have been synthesized using Fast Current Driven Synthesis method. • All the synthesized frameworks are fully crystalline and porous. • Morphology of framework can be tuned with bIm ligand fraction. • Mixed ligand strategy is highly suitable for tuning the pore architecture of ZIFs. • Pore interconnectivity is also altered in these frameworks as confirmed by positronium diffusion measurements.

N-Sulfonyl Bisimidazoline Ligands and Their Applications in Pd(II)-Catalyzed Asymmetric Addition toward α-Tertiary Amines.

A new class of chiral N-sulfonyl bisimidazoline (Bim) ligands have been designed, prepared, and applied in Pd(II)-catalyzed asymmetric addition of arylboronic acids to isatin-derived N-Boc ketimines. The combination of Pd(OCOCF3)2 and N-tosyl Bim ligand shows high catalytic activity and excellent asymmetric induction, enabling asymmetric addition to offer α-tertiary amines with generally good to high yields and excellent enantioselectivity (up to 96% yield, 96% ee). This asymmetric Pd(II) catalysis can tolerate air conditions, providing a practical and operationally simple protocol toward the construction of an enantioenriched α-tertiary stereocenter.

From helix to helical pores: solid-state crystalline conversions triggered by gas-solid reactions.

Two one-dimensional (1D) helical coordination polymers, CuBIm-Cl and CuBIm-Br (BIm = 1,2-bis((5H-imidazol-4-yl)-methylene)hydrazine), are constructed from Cu2+ ions, halides and mono-deprotonated BIm. Solid-state crystalline conversions of CuBIm-Cl and CuBIm-Br to a gyroidal metal-organic framework (MOF) STU-3 which is composed of Cu ions and Bim ligands are observed through a gas-solid reaction, where the gas is methylamine.

Co−MOFs with 1,1′-(5-methyl-1,3-phenylene)bis(1H-imidazole) and aromatic carboxylates as coligands: synthesis, structure, and spectroscopic and thermal characterizations

Four cobalt(II) compounds, [Co(Bim)(IA)(H2O)2]n·0.5nH2O (1), [Co(Bim)(MA)(H2O)2]n (2), [Co2(Bim)2(MA)2]n·nH2O (3), and [Co3(Bim)4(TA)2(H2O)2]n·2.5nH2O (4), have been synthesized by solvothermal reactions of cobalt(II) salts with 1,1′-(5-methyl-1,3-phenylene)bis(1H-imidazole) [Bim] and aromatic polycarboxylic acids (H2IA = isophthalic acid, H2MA = 5-methylisophthalic acid, and H3TA = trimesic acid) as coligands. The four complexes were characterized by IR and UV−vis spectra, elemental analyses, X-ray powder and single-crystal diffractions, and thermogravimetric analyses (TGAs). 1 features a zigzag polymeric macrocycle chain containing a nanotubular channel, which is constructed by bridging the folded 20-membered macrocyclic [Co2(Bim)2] subunits with IA ligands. 2 represents a double-chain structure containing 18-membered macrocyclic [Co2(Bim)(MA)] subunits. Both 3 and 4 are 2-D porous coordination polymers but have different architectures. In 3, cage-like [Co4(Bim)2(MA)4] subunits are 4-connected nodes that are further bridged by another half-set of Bim ligands to form a 2-D helical structure containing one-dimensional achiral channels and alternately arranged left- and right-handed helical tubular channels. In 4, Bim ligands bridge three crystallographically independent Co centers into sharply distorted left- and right-handed helices which are further connected by TA ligands to form a meso layer about 3.0 nm monolayer thickness with a unique (3,4)-connected topology. The structural diversities of coordination polymers 1–4 are tuned by the flexible coordination number of Co and coligand polycarboxylates. Thermal analyses show that the main frameworks of all compounds remain stable to 352 °C. Moreover, the interesting color changes of crystals 1–4, varying from pink to purple and dark blue, result from the d → d* transitions of chromophoric Co2+ in different coordination geometries as determined by the UV–vis spectra in combination with crystal structure analyses.

Highly modulated bisindoles: ligands for copper‐catalyzed Sonogashira reaction

Bisindoles (BIMs) were modulated as powerful N,N′ donor ligands for the copper‐catalyzed Sonogashira reaction. Ligand screening experiments on 11 BIM compounds found that 3,3′‐(4‐chlorophenyl)methylenebis(1‐methyl‐1H‐indole) (10%) efficiently accelerated CuCl (5%)‐catalyzed cross‐coupling of aryl iodides with terminal alkynes. A wide range of substituted aryl iodides and/or alkyl‐ and aryl‐substituted terminal alkynes were examined, leading to the corresponding coupling products with yields up to 99%. An efficient and scalable protocol for the synthesis of BIM ligands on a gram scale, with extremely low catalyst loading of o‐ClC6H4NH3+Cl−, was also developed with a reaction time of 20 min with yields up to 93%. This novel N,N′ ligand was air‐stable, easily available and highly modulated with low copper loading. Copyright © 2016 John Wiley & Sons, Ltd.

New dinuclear copper complexes incorporating bis(imidazolyl) based ligands and bidentate–monodentate oxalate bridges. Crystal structure and magnetic properties of [Cu2(BIM)2(C2O4)2]·4H2O and [Cu2(BIK)2(C2O4)2] (BIM = bis(2-imidazolyl)methane), BIK = bis(2-imidazolyl)ketone). Exploring magneto-structural correlations

This paper reports the synthesis, X-ray crystal structure and magnetic characterization of two novel copper(II) dinuclear compounds including bis(imidazolyl) ligands and oxalate anions, [Cu2(BIM)2(C2O4)2]·4H2O (1) (BIM=bis(2-imidazolyl)methane) and [Cu2(BIK)2(C2O4)2] (2) (BIK=bis(2-imidazolyl)ketone). The oxalate anion acts as bidentate–monodentate in both cases, although it exhibits different coordination bridging modes: whereas in compound 1 a μ1,1,2-oxalato is observed, a μ1,2,3-oxalato is found in compound 2. In both cases, the 3D framework is held together by a combination of H-bonding and aromatic-aromatic interactions provided by the convenient structural features of BIM and BIK ligands and oxalate. EPR spectra are indicative of an essentially dx2-y2 ground state for the copper(II) ions in both compounds. Magnetic susceptibility measurements reveal the existence of weak antiferromagnetic exchange interactions between the copper(II) ions (2J=−0.33(1)cm−1 for compound 1 and 2J=−1.45 (1)cm−1 for compound 2. Finally, the reported values of the singlet–triplet gap are compared with those observed in related copper(II) compounds with bidentate–monodentate out-of-plane oxalato bridges.

Tuning the Dimensionality of Polyoxometalate-Based Materials by Using a Mixture of Ligands

Five molecular one-, two-, or three-dimensional (1D, 2D, or 3D) organic–inorganic hybrid polyoxometalates (POMs) based on the {ε-PMoV8MoVI4O40Zn4} (εZn) Keggin unit have been synthesized under hydrothermal conditions using a mixture of O- and N-donor ligands. (TBA)6[PMoV8MoVI4O37(OH)3Zn4]2(C14H8O4)3·6H2O (ε2(biphen)3) is a 3D material with two interpenetrated networks built from dimeric (εZn)2 POMs linked by 4,4′-biphenyldicarboxylate (biphen) ligands. (TBA)2[PMoV8MoVI4O38(OH)2Zn4](C7H6N2)3(C14H8O4)1/2·H2O (ε(bim)3(biphen)1/2), (TBA)3[PMoV8MoVI4O38(OH)2Zn4](C7H6N2)2(C8H4O4)·6H2O (ε(bim)2(isop)), (TBA)7/3[PMoV8MoVI4O38(OH)2Zn4](C7H6N2)8/3(C8H4O4)2/3 (ε(bim)8/3(bdc)2/3), and (TBA)3[PMoV8MoVI4O38(OH)2Zn4](C7H6N2)2(C9H3O6)2/3·6H2O (ε(bim)2(trim)2/3) all consist of monomeric εZn units bound to two types of organic ligands: benzimidazole (bim) and one of the following carboxylate ligands: biphen, 1,3-benzenedicarboxylate (isop), 1,4-benzenedicarboxylate (bdc), or 1,3,5-benzenetricarboxylate (trim) ligands. While ε(bim)3(biphen)1/2 is a molecular complex, ε(bim)2(isop) and ε(bim)8/3(bdc)2/3 adopt a chain arrangement, and ε(bim)2(trim)2/3 is a 2D compound. In these materials, the limitation of the dimensionality is a direct consequence of the protonation of the nitrogen atom of the bim ligands. The electrocatalytic activity for the hydrogen evolution reaction (HER) of these five new POM-based coordination polymers has been studied, showing that their performance depends mainly on the presence of the εZn Keggin units but also on their structure. Modified electrodes fabricated with ε(bim)2(trim)2/3 entrapped in a carbon paste revealed that this hybrid is the most efficient electrocatalyst of the series, being stable and catalyzing the HER in the pH 1–5 range.

A 2-D organic–inorganic supramolecular layer based on a {P2Mo5} cluster bridged by Mn(II) and pentanuclear fragment linker

An organic–inorganic hybrid based on {P2Mo5} clusters, (H2bim)3[{Na0.5(H2O)0.5}2{Mn(OH)4(H2O)2}{Na0.5(H2bim)}2{Mn(H2O)4(P2Mo5O23)2}]·4H2O (1) (bim = 2,2′-biimidazole), was hydrothermally synthesized and characterized by elemental analyses, IR, TG, UV, and single crystal X-ray diffraction analyses. In 1, four Na ions, one Mn, and two bim ligands are linked by four μ–O bridges to form unusual pentanuclear fragments [{Na0.5(H2O)0.5}2{Mn(OH)4(H2O)2}{Na0.5(H2bim)}2]. Each pentanuclear segment links adjacent to four Standberg units to form supramolecular dimer chains, which are further connected by Mn(H2O)4 linkers to yield infinite 2-D layer. Two kinds of cage-like pores are observed in alternating type along the crystallographic b axis in which protonated H2bim ligands fill one sort of pores. Electrochemical and fluorescent properties of 1 have been investigated.

Assembly and Catalytic Properties of Cobalt(II) and Copper(II) Coordination Polymers Based on Bis(imidazole) and Carboxylic Acid Mixed Ligands

AbstractTwo CoII/CuII coordination polymers, [Co(bim)(ip)]n (1) and [Cu3(nip)2(OH)(bim)(H2O)]n (2) [bim = bis(imidazol‐1‐yl)methane, H2ip = isophthalic acid and H2nip = 5‐nitroisophthalic acid], were synthesized by reactions of metal acetate with H2ip or H2nip in the presence of bim ligand under hydrothermal conditions. The polymers were characterized by elemental analyses, IR spectroscopy, TGA, XRPD, and single‐crystal X‐ray diffraction. Compound 1 shows a 2D (4, 4) layer structure with CoII ions at the nodes, which is further extended in to a 3D supramolecular network through C–H···π interactions. Compound 2 manifests a four‐connected {Cu5(OH)2}8+ pentameric kernel, which is bridged by bim ligand molecules and two kinds of nip ligands with different coordination modes. This complex also displays a 2D (4, 4) network, which is constructed from pentanuclear CuII clusters as secondary building unit (SBU). In addition, the catalytic properties of the title compounds for the degradation of congo red were investigated.

Two three-dimensional cadmium supramolecular architectures containing extensive hydrogen-bonding networks based on CdSO4 and bis-imidazole ligands

In this study, two novel three-dimensional (3D) supramolecular networks, [Cd(BIM)2(SO4)(H2O)]·(C2H5OH) (H2O)2 (1) and [Cd(2-mBIM)(SO4)(H2O)3]·H2O (2) [BIM=bis(imidazol-1-yl)-methane, 2-mBIM=bis(2-methylimidazol-1-yl)methane], were synthesized by the reactions of CdSO4 with BIM or 2-mBIM ligand via solvent diffusion methods. The networks were then characterized by elemental analyses, IR, TGA, and X-ray diffraction. Both compounds 1 and 2 have a 3D hydrogen-bonding network with an infinite one-dimensional (1D) double chain structure and an infinite 1D helix channel, respectively. These results suggest that the subtle change in the ligand structure may have a strong influence on the resulting architectures of the metal–organic frameworks. The solid-state luminescent spectra of compounds 1 and 2 indicate weak fluorescent emissions at ca. 338 and 389nm, respectively.

Two three-dimensional pillared metal–olsalazine complexes based on infinite rod-shaped secondary building units

The first two three-dimensional (3D) pillared metal–olsalazine complexes, namely [Co(osa)0.5(bim)0.5(H2O)] (1) and [Cd(osa)0.5(bim)0.5(H2O)] (2) (H4osa=3,3-azo-bis(6-hydroxybenzoic acid), bim=1,4-bis(imidazol-1-yl)butane) have been hydrothermally synthesized and further characterized by single-crystal X-ray diffraction, powder X-ray diffraction, elemental analysis, IR spectra and TG analyses. Compounds 1 and 2 are isostructural, and their frameworks are composed of infinite rod-shaped secondary building units (SBUs) that are bridged by osa ligands to form 2D layers, which are further pillared by bim ligands in the third dimension. To the best of our knowledge, it is the first time that 3D pillared-layer frameworks involving infinite rod-shaped SBUs have been obtained in the realm of metal–olsalazine complexes. The magnetic property of 1 and photoluminescence of 2 have also been investigated.

Largest discrete supertetrahedral clusters synthesized in ionic liquids

Four discrete T5 cluster compounds with Cu–M–S constituents (M = In for compound 1, Ga for 2–4) have been synthesized in an ionic liquid (IL) [Bmmim]Cl (Bmmim = 1-butyl-2,3-dimethyl-imidazolium), which represent the largest molecular clusters in a Tn series. The in situ decomposition of the IL generates the Bim ligand (Bim = 1-butyl-2-methyl-imidazole) that directly coordinates to some of the corner Ga3+ ions of the T5 clusters in 3–4, leading to the formation of the first inorganic–organic hybrid T5 clusters. 2–4 show significantly broad photoluminescent emission bands ranging from 500 to 800 nm with a full width at half maximum (fwhm) at about 180 nm. This research provides a new method for synthesizing molecular metal chalcogenides that uses ILs as a reactive solvent and stabilizer.

Synthesis, structure and photoluminescence of two cadmium coordination polymers with 1,3-benzenedicarboxylate and two flexible bis-imidazole ligands

Two new coordination polymers, [Cd 2(2-mBIM) 2(1,3-BDC) 2] n ( 1) and [Cd(BIM)(1,3-BDC)] n ( 2) [BIM = bis(imidazol-1-yl)-methane, 2-mBIM = bis(2-methylimidazol-1-yl)methane], were synthesized by reactions of CdCl 2 with 2-mBIM or BIM ligand in the presence of 1,3-benzenedicarboxylic acid. The polymers were then characterized by elemental analyses, IR, TGA, and X-ray diffraction. Compound 1 is a two-dimensional (2D) twofold parallel interpenetration network with a (4, 4) connected topology. Compound 2 is a 2D double-layer framework containing [Cd 2(COO) 4] subunits. The results of this study suggest that subtle changes in the ligand structure may have a great impact on the resulting architectures of the metal–organic frameworks. Solid-state luminescent spectra of compounds 1 and 2 indicate weak fluorescent emissions at ca. 389 and 302 nm, respectively.

Assembly of two coordination polymers [Cu(BIM)(suc)] n and [Cd(BIM)(ox)(H2O)] n constructed from bis(imidazol-1-yl)methane

Two coordination polymers [Cu(BIM)(suc)] n (1) and [Cd(BIM)(ox)(H2O)] n (2) (where BIM = bis(imidazol-1-yl)methane, suc = succinic dianion, and ox = oxalic dianion) have been solvothermally synthesized and characterized by single-crystal X-ray diffraction. Complex 1 crystallizes in the monoclinic space group C2/c with a = 12.2302(8) Å, b = 11.4007(6) Å, c = 10.1791(6) Å, β = 118.4090(10)°, V = 1248.38(13) Å3, and Z = 4. Cu(II) is square planar with nitrogen from BIM ligand and oxygen from the suc in the trans arrangement. Each BIM is bidentate bridging two Cu(II)s to generate a 1-D zigzag chain; the suc bridges two Cu(II)s in a monodentate gauche conformation, which results in the formation of wavy 2-D (4, 4) grid arrays. Complex 2 crystallizes in the monoclinic space group P2(1)/n with a = 10.8042(3) Å, b = 9.1053(2) Å, c = 12.0134(6) Å, β = 96.394(1)°, V = 1174.47(7) Å3, and Z = 4. Cd(II) is coordinated in a distorted decahedral geometry. Each BIM is bidentate bridging two Cd(II)s to form a 1-D infinite zigzag chain; each ox bridges two neighboring Cd(II)s in a distinct zigzag chain in a chelating/chelating coordination mode, which extends the 1-D chain to a 2-D supramolecular network.