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Nucleophilic substitutes provide a new platform to design and synthesize novel bifunctional heterogeneous catalysts for carbon dioxide cycloaddition reaction with epoxides. Herein, in this work, UMCM-15 was fabricated and modified with various nucleophilic ligands containing bromine, amine and hydroxyl functional groups. The resultant prepared compounds were utilized as bifunctional synergetic catalysts for the chemical fixation of carbon dioxide. The catalysts can efficiently catalyze epoxides and carbon dioxide under relatively mild conditions in the absence of co-catalyst and solvent. The contemporaneous presence of Lewis acid and basic centers in the framework resulted in high catalytic activity and turnover number (TON) value for the production of cyclic carbonates compared to other reported compounds indicating superiority of the synthesized catalysts. Among diverse applied bifunctional catalysts, bromine-functionalized frameworks exhibited the highest catalytic performance owing to the presence of multiple electron pairs and the great tendency to donate electron pairs. [Display omitted] • Diverse nucleophilic functional groups were successfully modified on an unsaturated Zn-based MOF. • The novel modified framework was utilized as superior catalysts in the aspect of CO 2 cycloaddition reactions. • Cycloaddition reactions accomplished in the absence of either co-catalyst or solvent under relatively mild condition. • This is the first report utilizing and comparing various nucleophilic functional groups as co-catalyst in cycloaddition reaction. • The prepared 3D porous structures display much higher activity and TON than other previously reported catalysts. • The catalyst could be reused. [ABSTRACT FROM AUTHOR]

[Display omitted] In this work, (metal- organic framework) MOF-808, defective MOF-808 (DF), sulfonated MOF-808 (MOF-808-SO 4), and defective/sulfonated MOF-808 (MOF-808-SO 4 (DF)) were synthesized, modified and assessed as catalysts for the conversion of glycerol to solketal for use as a bio-additive to fuel. We also report that zirconium-based MOF-808 (Zr) with partial defects can be fabricated using isophthalic acid ligands to improve the properties of catalysis. The characterization results confirm that MOF-808-SO 4 (DF) had more acidic properties than the parent MOF-808 and MOF-808 (DF). Amongst the catalysts assessed, MOF-808-SO 4 (DF) recorded the maximum conversion (about 78 % after 30 min) and selectivity (about 98 %) towards solketal. Two mechanisms have been discussed based on the kinds of acidity. In a simple recycling process, after four repetitions of catalytic reaction using the same catalyst sample was reused without any loss of activity. The correlation between the acidic properties of the catalysts and selectivity of the solketal was investigated. The correlation between the acidic properties of the catalysts and the selectivity of the solketal was investigated. [ABSTRACT FROM AUTHOR]

( E )-4-hydroxy-3-((quinolin-8-ylimino)methyl)benzoic acid, (H 2 L), was synthesized and employed in the synthesis of metal complex or coordination polymers (CPs) namely, [Co(HL) 2 ]NO 3 ·3DMF, 1 , {[Cu(L)(H 2 O)]·H 2 O} n , 2 , and {[ZnL]·DMF} n , 3 . Compounds have been characterized by CHN analysis, 1 H NMR and IR and UV–Vis spectroscopy. Structures of 1 , 2 and 3 were determined by X-ray crystallography. Compound 1 is a discrete mononuclear complex, compound 2 consists of infinite one-dimensional zig-zag chains and compound 3 displays a two-dimensional coordination polymer, uninodal shubnikov tetragonal plane network with (4 4 ·6 2 ) point symbol. Compound 3 exhibits strong fluorescence emission upon excitation at room temperature. In addition, gas sensing property of compound 3 as a thin film on one side of double sided tap on the glass substrate have also been discussed. [ABSTRACT FROM AUTHOR]

Three flexible chelating and bridging ligands, (E)-N-(pyridin-2-ylmethylene)-1-(pyridin-3-yl)methanamine (L 1 ), 1-(pyridine-2-yl)-N-(pyridin-3-ylmethyl)methanamine (L 1 ′), (E)-N-(pyridin-2-ylmethylene)-1-(pyridin-4-yl)methanamine (L 2 ), have been synthesized. The reaction of these ligands with various metal salts yielded a series of compounds, namely [Cu 2 (L 1 )(PPh 3 ) 2 I 2 ] 2 ( 1 ), [Cu 2 (L 2 )(PPh 3 ) 2 I 2 ] n ( 2 ), [CuL 1 (NO 3 ) 2 ] 2 ( 3 ), [ZnL 1 (NO 3 ) 2 ] 2 ( 4 ), [CdL 1 (NO 3 ) 2 ] 2 [( 5 ), [CdL 1 ′ (NO 3 ) 2 ] 2 ( 6 ) and [HgL 1 Cl 2 ] n ( 7 ). The compounds were characterized by elemental analysis, spectroscopic methods (IR, UV–Vis) and X-ray crystallography. X-ray structural analysis of compound 1 reveals the formation of a centrosymmetric tetranuclear compound. The repeat unit of coordination polymer 2 comprises a Cu 2 I 2 unit with a triphenyl phosphane substituent on Cu1 linked to an adjacent Cu 2 I 2 unit by the ligand L 2 that acts as a bridge. Compounds 3 , 4 , 5 and 6 exhibit a common metallo-cyclophane [M 2 ( L ) 2 (NO 3 ) 4 ] skeleton. Two M 2+ cations are linked by two L 1 ligands and these ligands chelate to each metal atom through the imine nitrogen (or amine nitrogen) atoms and the nitrogen atom of the 2-pyridyl ring, and bind to the other metal atom of the pair via the nitrogen atoms of the 3-pyridyl rings. Structural studies of 7 revealed the formation of a coordination polymer in which the polymer chain propagates in helical spirals along a twofold screw axis parallel to b . The metal coordination geometries and coordination of the nitrato anions to the metals are noted and discussed. [ABSTRACT FROM AUTHOR]

Abstract: We describe here a complex precursor hydrothermal route to prepare uniform Cu2O microsphere, spherical composite of Cu2O/Cu nanocrystals with controlled size and composition and a wide range of novel copper microstructures using {[Cyclohexyl(phosphonomethyl)amino]methyl}phosphonic acid (dP) as both the complexing and reducing agent. It is noteworthy that changing the characteristic of initially formed Cu2+-aminodiphosphonate complex precursor via manipulating synthetic parameters was crucial to the growth of the final product. Time order of growth process at pH=9 has been revealed: (1) aggregation of Cu2O nanoparticles to form spherical microstructure, (2) recrystallization of Cu2O nanoparticles parallel to reductive transformation from Cu2O to Cu to produce spherical Cu2O/Cu microstructure consisting of larger nanoparticles and (3) increasing the nanoparticle size of Cu2O/Cu microstructure as the content of Cu phase increases. At pH=14, only pure Cu microcrystals of different shapes were obtained. The effects of concentration and molar ratio of starting materials, reaction time and temperature on the growth process and morphology of copper microcrystals were investigated. Finally, a possible growth mechanism is proposed. The obtained samples have been characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and Fourier Transform infrared spectroscopy. [Copyright &y& Elsevier]

Abstract: 3-(2′-Pyridylmethyleneamino)pyridine (L) and its homo and heterometallic coordination polymers [ML(NO3)2] n , (M=Co, Zn, Cd; 1–3) and [MM′L2(NO3)2] n , (M, M′=Co, Zn, Cd; 4–6) have been synthesized and characterized by CHN analysis, IR and UV–Vis spectroscopy. The crystal structures of the compounds were determined from single crystal X-ray diffraction. Structural studies of compounds revealed the crystals are isomorphous (monoclinic, P 21/c). The coordination polyhedron about the M(II) center in the compounds is best described as distorted octahedral. Each L is chelated to a metal center (M) and also linked to another metal atom to form an infinite helical chain along the b axis. The formation of a series of composite crystals based on epitaxial growth of crystalline layers on preformed crystals has also been reported. The crystal growth of the zinc compound was also studied in the presence of KI. Thermogravimetric investigations of the compounds have also been discussed. [Copyright &y& Elsevier]

Abstract: Using surfactant-assistant solvo/hydrothermal methods, nanoscale calcium aminodiphosphonate species (CadP) with different morphologies, namely nanobelts, nanorods, and nano-networks have been synthesized. The final products with various morphologies have been obtained through controlled experimental conditions such as type of surfactant (with different concentrations), solvent, and base. Selected samples have been characterized by elemental analysis, FT-IR, TGA, XRD, SEM and TEM. Removal of a cationic/basic dye (methylene blue) from aqueous solution was investigated using synthesized nano-networks (CadP-N) as adsorbents. Effects of process parameters such as adsorbent morphology, adsorbent dose, pH, contact time, and initial dye concentration on the extent of methylene blue (MB) adsorption were investigated. Both the Langmuir and the Freundlich isotherms are fit to explain the MB adsorption on CadP-N. The maximum adsorption capacity of CadP-N was found to be 138.89mg/g. Desorption experiments showed that CadP-N has the ability to remove adsorptive on the MB treatment for recycling use. [Copyright &y& Elsevier]

Abstract: The hydrothermal reaction of NaN3, acetonitrile and KSCN in the presence of [Cu(CH3CN)4]ClO4 yields two new d10 coordination polymers, [Cu2(μ3-SCN)(μ4-mtta)] n (1) and its supramolecular isomer [Cu2(μ4-SCN)(μ4-mtta)] n (2) (mtta=5-methyl tetrazolate), involving in situ formation of the 5-methyltetrazolate ligand by cycloaddition of nitrile and azide. Compounds 1 and 2 were both found to crystallize in the orthorhombic Pbam system, with different unit cells, exhibiting interesting examples of supramolecular polymorphism. Both compounds are built by [Cu2mtta]+ n ribbons connected by thiocyanate anions which act as μ3- and μ4-ligands in 1 and 2, leading to 2D and 3D coordination polymers, respectively. Short Cu(I)⋯Cu(I) distances were found in 1 and 2, which may be attributed to metallophilic Cu⋯Cu interactions. Thermogravimetric analyses indicate that compounds 1 and 2 are stable up to 265 and 340°C, respectively. [Copyright &y& Elsevier]

Abstract: The catalytic reduction of 2,2′-dinitrobiphenyl with different molar ratios of hydrazine hydrate resulted in two different compounds; benzo[c]cinnoline (L1) and 2,2′-diaminobiphenyl. N2,N2′-bis(3-phenylallylidene)biphenyl-2,2′-diamine (L2) has been synthesized by the condensation of 2,2′-diaminobiphenyl with cinnamaldehyde. Complexes of the type ML1 2X2 and ML2X2 (M=Co(II), Zn(II); X=Cl, Br or I and Hg(L2)Cl2) have been synthesized and characterized by CHN analysis, IR, 1H NMR and UV–Vis spectroscopy. The crystal structures of Co(L1)2Cl2, Zn(L1)2Br2 and Hg(L2)Cl2 were determined using single crystal X-ray diffraction. In these three complexes, the coordination polyhedron about the central metal ion is best described as a distorted tetrahedron. The Co(L1)2Cl2, and Zn(L1)2Br2 complexes exhibit supramolecular structures resulting from π–π stacking of the benzo[c]cinnoline ligands. The diimine ligand, L2, in the Hg(L2)Cl2 complex coordinates to Hg(II) through the two nitrogens of the two phenyl rings to form a seven-membered metallocycle. Furthermore, the ligand prefers a trans–trans arrangement in the Hg(L2)Cl2 complex. [Copyright &y& Elsevier]

Abstract: The bis[4-(2-pyridylmethyleneamino)phenyl]methane ligand L and it’s dinuclear double-helical mercury complex, 1 have been synthesized and characterized by CHN analysis, IR and UV–Vis spectroscopy. The crystal structures of L and 1 were determined from single crystal X-ray diffraction. The molecule of ligand L is generated by a crystallographic two-fold axis and adopts an E configuration with respect to the Che dihedral angles between the planes of the pyridine ring, chelate ring, and the benzene ring in L show coplanarity of these planes, leading to a considerable planarity of these moieties. The two phenyl rings of the diarylmethane spacer of L are inclined at an angle of 8.75° to one another, so that L forms an appreciable V shape. The asymmetric unit of 1 contains two independent Hg atoms, two ligands and four nitrate anions. The ligands wrap around the two mercury canters forming a double-helical structure. Three nitrate anions act as a bidentate ligand and the other nitrate anion is uncoordinated. [ABSTRACT FROM AUTHOR]

Abstract: Four platinum(II) complexes, [PtCl2L] (L=(4-fluorophenyl)pyridin-2-ylmethylene-amine, 1; (4-chlorophenyl)pyridin-2-ylmethyleneamine, 2; (4-bromophenyl)pyridin-2-ylmethyleneamine, 3 and (4-iodophenyl)pyridin-2-ylmethyleneamine, 4) have been synthesized and characterized by CHN analysis, IR and UV–Vis spectroscopy. The crystal structures of 1 and 2 were determined using single crystal X-ray diffraction. The coordination polyhedron about the platinum (II) center in the complexes is best described as distorted square planar. The complexes undergo stacking to form a zigzag Pt···Pt···Pt chain containing both short (3.57(7)Å in 1 and 3.62(8)Å in 2) and long (5.16(7)Å in 1 and 5.41(9)Å in 2) Pt···Pt separations through the crystal. The compounds absorb moderately in the visible region, owing to a charge-transfer-to-diimine electronic transition. The redox potentials are approximately insensitive to the substituents on the phenyl ring of the ligands. [Copyright &y& Elsevier]

Abstract: Four mercury(I) complexes, [L2HgHgL2](NO3)2 (L2 =(4-fluorophenyl)pyridin-2-ylmethyleneamine, 1; (4-chlorophenyl)pyridin-2-ylmethyleneamine, 2; (4-bromophenyl)pyridin-2-ylmethyleneamine, 3 and (4-iodophenyl)pyridin-2-ylmethyleneamine, 4) have been synthesized and characterized by CHN analysis, IR and UV–Vis spectroscopy. The crystal structures of 1 and 3 were determined by single crystal X-ray spectroscopy. These complexes contain the moiety with a mercury–mercury bonded core, in which one diimine ligand is coordinated to each mercury atom. The Hg atoms have an additional axial interaction with the oxygen atom of the anion in both complexes. Complex 1 shows a step in the Hg–Hg bond due to the parallel configuration of the planar ligands. However, the ligand planes in the complex 3 are nearly planar and these planes are approximately perpendicular to each other. Supramolecular structures were built in both complexes via π–π stacking of the diimine ligands. [Copyright &y& Elsevier]

Abstract: Four new ligands, (4-methyl-phenyl)-pyridin-2-ylmethylene-amine (A), (2,3-dimethyl-phenyl)-pyridin-2-ylmethylene-amine (B), (2,4-dimethyl-phenyl)-pyridin-2-ylmethylene-amine (C) and (2,5-dimethyl-phenyl)-pyridin-2-ylmethylene-amine (D), and their corresponding copper(I) complexes, [Cu(A)2]ClO4 (1a), [Cu(B)2]ClO4 (1b), [Cu(C)2]ClO4 (1c), [Cu(D)2]ClO4 (1d), [Cu(A)(PPh3)2]ClO4 (2a), [Cu(B)(PPh3)2]ClO4 (2b), [Cu(C)(PPh3)2]ClO4 (2c) and [Cu(D)(PPh3)2]ClO4 (2d), have been synthesized and characterized by CHN analyses, 1H and 13C NMR, IR and UV–Vis spectroscopy. The crystal structures of [Cu(B)2]ClO4 (1b), [Cu(C)2]ClO4 (1c) and [Cu(A)(PPh3)2]ClO4 ·1/2CH3CN (2a) were determined from single crystal X-ray diffraction. The coordination polyhedron about the copper(I) center in the three complexes is best described as a distorted tetrahedron. A quasireversible redox behavior is observed for the complexes. [Copyright &y& Elsevier]

We report a type of magnetic recyclable Fe 3 O 4 @SiO 2 @PCN-222(Fe) photocatalyst based on the Zr-porphyrin metal-organic framework (MOF) for the efficient removal of cationic (Rhodamine B (RhB)) and anionic (Erythrosine B (EryB), and Rose Bengal (RoseB)) dyes from wastewater. The synthesized MOF is an efficient visible-light-active photocatalyst for the degradation of large dyes (RhB, EryB, and RoseB). XRD, FT-IR, SEM, TGA, TEM, BET, and DRS were employed to elucidate the structural and morphological characteristics of the obtained photocatalyst. Furthermore, the conduction band of the synthesized photocatalyst was derived from the obtained Mott-Schottky plots. The photocatalytic activity of Fe 3 O 4 @SiO 2 @PCN-222(Fe) under visible light was higher than Fe 3 O 4 @SiO 2 @PCN-222(no metal), the influence of metalloporphyrin on degradation efficiency was studied and a mechanism of degradation was proposed. [Display omitted] • A magnetic photocatalyst based on Zr-porphyrin metal-organic framework (MOF) has been prepared and studied. • Due to the magnetic properties of Fe 3 O 4 @SiO 2 @PCN-222(Fe) it can be easily separated. • The influence of the metal center of metalloporphyrin on the photodegradation of various dye pollutants has been investigated. • The aforementioned compound is a visible light photocatalyst in the presence of air bubbles. [ABSTRACT FROM AUTHOR]

• MIL-100-Cr was fabricated and cyanide functional groups were successfully incorporated into the framework. • The prepared cyano-bifunctional MOFs were employed as excellent catalysts in chemical fixation of CO 2. • The reactions carried out without the addition of either solvent or co-catalyst under mild conditions. • This is the first report utilizing cyanide functional groups as co-catalyst in cycloaddition reaction. • The synthesized 3D porous materials exhibit much higher performance, TON, and TOF than others previously reported catalysts. In the present work, a strategy for the incorporation of nitrogen-rich units to an unsaturated Cr-based MOF, MIL-100-Cr, is reported. Based on this strategy, various cyanide functional groups (diamino malononitrile, 1,3-phenylene diacetonitrile, and malononitrile) were incorporated into the framework and utilized as exceptional catalysts in the carbon dioxide fixation under mild, solvent, and co-catalyst free conditions. This is the first report on the application of cyano-bifunctional frameworks in cycloaddition reaction. The contemporaneous presence of accessible Lewis acid sites and pendent cyanide groups results in highly striking conversion and TON even for bulky and large substrates. High tendency and strong interaction of cyanide groups with CO 2 cause a synergetic effect in the performance of the catalysts. The role of different cyanide groups applied in this work has also been studied. The reaction wouldn't proceed in the presence of pristine MOF without co-catalyst addition. [ABSTRACT FROM AUTHOR]

• Amine groups were successfully modified on an unsaturated Cr-based MOF. • The novel amino-functionalized MOF was utilized as superior catalysts in the aspect of CO 2 cycloaddition reactions. • Cycloaddition reactions accomplished in the absence of either co-catalyst or solvent under relatively mild condition. • Different orientation types of catalysts affect catalytic activity. • The prepared 3D porous structures display much higher activity and TON than other previously reported catalysts. Herein, we report the adoption of adjustable composition nitrogen-rich units via introduction of diverse amine groups to an unsaturated metal organic framework, MIL-100(Cr), and the application of the products obtained as novel catalysts in the aspect of CO 2 cycloaddition reactions to afford cyclic carbonates in the absence of co-catalyst and solvent under mild conditions (60 °C, 1 MPa). Incorporation of amine groups to the frameworks leads to substantial increment in the catalytic performance of the structures. The concomitant presence of acidic and basic sites in the structure causes great conversion and selectivity in cycloaddition reactions even for large and bulky epoxides. The comparison of various groups of amines (2-aminopyridine, 1,2-phenylene diamine, 3-aminopyridine and ethylene diamine) incorporated on the surface with different orientations demonstrates the effect of the orientation type in catalytic activity. CO 2 gas sorption measurement helps to better understand the process of catalytic activity. The pristine MOF is unable to progress the reaction without addition of co-catalyst. [ABSTRACT FROM AUTHOR]

A series of complexes of the type M(Phca2en)X2, where Phca2en=N,N′-bis(β-phenyl-cinnamaldehyde)-1,2-diiminoethane, M(II)=Co, Ni or Zn and X=Cl, Br, I or NCS have been synthesized and characterized. The crystal and molecular structures of Co(Phca2en)Cl2 (2), Ni(Phca2en)Br2 (5) and Zn(Phca2en)Cl2 (6) were determined by X-ray crystallography from single-crystal data. Complexes 2 and 5 are isomorph and isostructure, in which the coordination polyhedron about the central metal ion is distorted tetrahedron with Cl&z.sbnd;Co&z.sbnd;Cl, 110.17(6)°; N&z.sbnd;Co&z.sbnd;N, 84.16(13)° and Cl&z.sbnd;Zn&z.sbnd;Cl, 112.02(6)°; N&z.sbnd;Zn&z.sbnd;N, 83.45(16)°. The complex 5 crystallizes in triclinic system with two molecules per asymmetric unit, both having nickel ion in distorted tetrahedral geometry, Br&z.sbnd;Ni&z.sbnd;Br, 122.645(18)° and 125.729(18)°; N&z.sbnd;Ni&z.sbnd;N, 84.63(9)° and 85.08(9)°. These structures consist of intermolecular hydrogen bonds of the type C&z.sbnd;H⋯X. The formation of the C&z.sbnd;H⋯M weak intramolecular hydrogen bonds due to the trapping of C&z.sbnd;H bonds in the vicinity of the metal atoms are reported for 2, 5 and 6. A 1H NMR study of Zn complexes gives further evidence for the presence of such interactions and their significance. The spectral properties of the above complexes are also discussed. [Copyright &y& Elsevier]