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In the present work, complexes of cobalt(II), copper(II), and zinc(II), 2-amino-4-methylpyrimidineand, and 2,3-diaminopyridine were successfully prepared and characterized using elemental analysis, UV-visible, and FTIR spectroscopy, as well as magnetic susceptibility measurements, molar conductance, TGA analysis, and X-ray diffraction. From elemental and spectral data, the formulae [M(L1)(L2)Cl2(H2O)] (where L1 = AMPY (2-amino-4-methylpyrimidine) and L2 = DAPY(2,3-diaminopyridine)) and M = Co(II) (2), Cu(II) (2), and Zn(II)) for the metal complexes have been proposed. The geometric structures of the mixed-ligand complexes were found to be octahedral around the metal ions, and the XRD patterns showed monoclinic crystal systems with space group P21. The mode of bonding was pentacoordinate for Cu and hexacoordinate for Zn and Co. Different features may result from the fact that not all molecules have the same electron distribution. For example, Zn and Co have larger electron densities in at least one of the chlorides in the HOMO compared with pentacoordinate Cu, which has a small electron distribution on the chloride. Thermal analysis indicated that all metal complexes are stable up to about 88 °C with thermodynamically favored overlapped chemical reactions. Excellent antibacterial and antifungal activity was shown by the three synthesized forms of the complexes. The Zn(II) complex had a high level of antioxidant activity with a DPPH scavenging of 91.5%, whereas the Cu(II) complex had a low level of antioxidant potential (16.5%). The docking tests also showed that all compounds had good binding energy levels (7.2–7.9 kcal mol−1). For this reason, all molecules can easily fit in the receptor protein's catalytic sites. However, the Co(II) complex is shown to be more active. [ABSTRACT FROM AUTHOR]

A new compound [CuICuII2(bpy)(pzta)2][HMo10O34] {CuICuII2-Mo10, pzta = 3-(pyrid-4-yl) pyrazole and bpy = 4,4'-bipyridine} was obtained by a hydrothermal reaction method and characterized by several tests including XPS, IR, UV, PXRD, luminescent spectroscopy and single crystal X-ray diffraction. The CuICuII2-Mo10 shows an unusual decamolybdate-encapsulated nanocage framework structure. Besides the novel structure, the CuICuII2-Mo10 was further used for photocatalytic hydrogen generation and it possesses an improved catalytic H2 productivity compared with its parent polyoxometalate (NH4)6Mo7O24·4H2O (Mo7) under identical experimental conditions. Namely, the photocatalytic H2 productivity of CuICuII2-Mo10 can reach 99.5 μmol−1 g−1 h−1, which is much higher than 42.35 μmol g−1 h−1 of Mo7. A new metal–organic compound with an intriguing decamolybdate-encapsulated nanocage framework was synthesized and applied as photocatalyst showing a high photocatalytic hydrogen activity. [ABSTRACT FROM AUTHOR]

The self-assembly of three MOFs with a series of structure differences in framework charge, metal nodes, topolpgy nets and porosity, not only demonstrates the great potential of mixed-ligands strategy to create novel high-porosity crystalline solids, but also highlights the structural directional effect of 3d metal ions based on varied coordination geometry preference. [Display omitted] • Two new and highly porous mixed-ligands MOFs were synthesized from H 3 btb and H 2 bdc. • The metal ions induced structural orientation and differentiation in mixed-ligands MOFs. • Two-steps gate-opening in gas sorption was found for flexible Mn(II) mixed-ligands MOFs. Mix-ligands strategy is highly efficient for the rational construction of MOFs with particular structure motifs and high porosity, yet challenging and requiring matching in hierarchical coordination assembly and synergetic crystallization. The solvothermal reactions of 1,3,5-tris[4-carboxyphenyl]benzene (H 3 btb) and 1,4-benzenedicarboxylic acid (H 2 bdc) with different 3d metal ions, generated highly porous mixed-ligands MOFs of [(CH 3) 2 NH 2 ] 2 [Mn 3 (btb) 2 (bdc)]·12DMF·3MeOH (Mn-btb-bdc) having anionic 3D frameworks constructed from linear [Mn 3 (COO) 8 ] nodes, [Co 4 (btb) 2 (bdc)(H 2 O) 3 ]·15DMF·7H 2 O (Co-btb-bdc) processing neutral frameworks constituted by linear [Co 3 (COO) 6 (H 2 O) 4 ] and paddle-wheel [Co 2 (COO) 4 (H 2 O) 2 ] nodes, as well as one single-ligand MOFs of [(CH 3) 2 NH 2 ][Cd(btb)(H 2 O)]·8DMF (Cd-btb-2fold) exhibiting 2-fold interpenetrated ths net frameworks due to the unsuccessful introduce of the coexisted bdc ligand. Two new topology net of 2,3,8-connected net with point symbol of (42·6) 2 (44·66·812·105·12)(6) and 2,3,4,6-connected net with Point Symbol of (4·82) 4 (42·811·102) 2 (84·122)(82) were found for Mn-btb-bdc and Co-btb-bdc. All these three MOFs are highly porous with void fractions of 60.9%, 52.2% and 61.4%, stemming from 3D-penetrated, 3D-penetrated and 1D channels, respectively. Such structural differentiations are attributed to the diversified electronic structure and coordination preference of different 3d metal ions, as well as the solvent template and temperature effects. Two-steps gate-opening behaviour in gas sorption isotherms was found in the flexible Mn-btb-bdc MOFs. [ABSTRACT FROM AUTHOR]

In the present work, complexes of cobalt(II), copper(II), and zinc(II), 2-amino-4-methylpyrimidineand, and 2,3-diaminopyridine were successfully prepared and characterized using elemental analysis, UV-visible, and FTIR spectroscopy, as well as magnetic susceptibility measurements, molar conductance, TGA analysis, and X-ray diffraction. From elemental and spectral data, the formulae [M(L1)(L2)Cl2(H2O)] (where L1 = AMPY (2-amino-4-methylpyrimidine) and L2 = DAPY(2,3-diaminopyridine)) and M = Co(II) (2), Cu(II) (2), and Zn(II)) for the metal complexes have been proposed. The geometric structures of the mixed-ligand complexes were found to be octahedral around the metal ions, and the XRD patterns showed monoclinic crystal systems with space group P21. The mode of bonding was pentacoordinate for Cu and hexacoordinate for Zn and Co. Different features may result from the fact that not all molecules have the same electron distribution. For example, Zn and Co have larger electron densities in at least one of the chlorides in the HOMO compared with pentacoordinate Cu, which has a small electron distribution on the chloride. Thermal analysis indicated that all metal complexes are stable up to about 88 °C with thermodynamically favored overlapped chemical reactions. Excellent antibacterial and antifungal activity was shown by the three synthesized forms of the complexes. The Zn(II) complex had a high level of antioxidant activity with a DPPH scavenging of 91.5%, whereas the Cu(II) complex had a low level of antioxidant potential (16.5%). The docking tests also showed that all compounds had good binding energy levels (7.2–7.9 kcal mol−1). For this reason, all molecules can easily fit in the receptor protein’s catalytic sites. However, the Co(II) complex is shown to be more active.

By adopting mixed‐ligand strategy, three Co(II)/Cd(II) metal–organic frameworks were prepared by hydrothermal reactions of Co(II)/Cd(II) acetate with 1,2‐phenylenediacetic acid or 1,3‐phenylenediacetic acid(1,2‐H2phda/1,3‐H2phda) combining with two imidazolyl/trazol/pyridyl‐type tectons, namely, {[Co(1,2‐phda)(bip)(H2O)2]·0.25H2O}n (1), {[Cd0.5(1,2‐phda)0.5(bip)0.5(H2O)0.5]·0.5H2O}n (2) and [Cd2(1,3‐phda)2(itmb)2]n (3) (bip = 3,5‐bis(1‐imidazoly)pyridine and itmb = 1‐(imidazo‐1‐ly)‐4‐(1,2,4‐trazol‐1‐ylmethyl)benzene). The single‐crystal X‐ray diffraction analyses show that three compounds contain various metal(II)‐carboxylate motifs, including carboxylate mononuclear (1), carboxylate chain (2), and carboxylate layer (3), which are further extended by two kinds of coligands to afford a vast diversity of the structures from 3‐connected {63}‐hcb topology (1), (4,4) grids layer (2) to 6‐connected {412·63} pcu topology (3). Furthermore, the photoluminescences of both Cd(II) complexes exhibit highly selective sensing of Fe3+ ion through fluorescence quenching, and may be used as a potential Fe3+ sensor material. [ABSTRACT FROM AUTHOR]

Two novel transition-metal coordination polymers with the formulas [Co(L1)(bbi)(H2O)]n (1) and {[Co(L2)(phen)]·H2O}n (2) (H2L1 = 1,4-naphthalenedi- carboxylic acid, H2L2 = 5-OH-1,3-benzenedicarboxylic acid, bbi = 1,1′-(1,4-butanediyl)bis(imidazole), phen = 1,10-phenanthroline) have been hydrothermally synthesized and characterized by techniques of single crystal X-ray diffraction, infrared spectra, elemental analysis, powder X-ray diffraction, and variable-temperature magnetic susceptibility measurements. X-ray crystal structure analyses reveal that complex 1 exhibits 2D framework with 4-connected sql topology and is further extended into a 3D supramolecular architecture via strong O–H···O and weak C–H···O hydrogen-bonding interactions, while complex 2 features a 1D ladder-like chain with a 3-connected (42·6) topological structure. Magnetic studies showed the presence of an antiferromagnetic interaction between adjacent Co(II) ions in both complexes. Two new mixed ligand complexes of cobalt based on N-heterocylic and carboxylate ligands were readily obtained and characterized. The topological structures, thermal stabilities and magnetic properties of which are observed and discussed. [ABSTRACT FROM AUTHOR]

For investigating the effects of different azacyclo-assisting ligands and O-donor bridging ligands on the structural construction, three different structural complexes, namely, {Zn(DBTA)(phen)(H 2 O)} n ( 1 ) (DBTA = 2, 5-Dibromo-terephthalic acid, phen = 1,10-Phenanthroline), [Zn(DBTA)(bimb)] n ( 2 ) (bimb (1,4-bis(imidazole-1-ylmethyl)benzene) and {[Zn 2 (bmimb)(PO 4 ) 2 ]·(H 2 O) 2 } n ( 3 ) (bmimb = 1,2-bis(methylimidazole-1-ylmethyl) benzene) have been constructed by different mixed-ligands and Zn atoms. Their structures have been characterized by single-crystal X-ray diffraction analysis, elemental analysis, and Infrared spectroscopy. Complex 1 exhibits a common 2D layer with 4,4-connected topology. Complex 2 features an interesting 2-fold interpenetrating net with the aid of long-chain flexible azacyclo-assisting ligands. Complex 3 shows 3D supramolecular architecture with tetranuclear water cluster filling in the pores. Their fluorescence properties were also measured. [ABSTRACT FROM AUTHOR]

We reported the design and synthesis of mixed ligands Cu-metal organic frameworks (MOFs), MOFs-2 and MOFs-3, and their application as the transport vehicles for the delivery of Ibuprofen (IBU) and doxorubicin hydrochloride (DOX). The unique MOFs with mixed ligands, 1,3,5-benzene tricarboxylate (BTC) and isophthalic acid (IPA), were easily prepared by hydro-thermal method, and their structures were well characterized by XRD, FTIR, and SEM imaging analysis. Single ligand MOFs with BTC or IPA only were also prepared and characterized as the control group. The biocompatibility of synthesized MOFs towards human cells, HEK 293A was evaluated by MTT assay. To demonstrate the practical applications of the prepared MOFs as the transport vehicles for drugs, the capability of loading and controlled release of IBU and DOX by MOFs-1, MOFs-2, MOFs-3, and MOFs-4 were then examined. In addition, the drug delivery efficiency of various MOFs with different ligands was investigated. [ABSTRACT FROM AUTHOR]

Mixed-ligand zinc(II) complex, {(pipzH)[Zn(hypydc)(btc)]·HO}, ( 1) was prepared with 4-hydroxypyridine-2,6-dicarboxylic acid (hypydcH), benzene-1,2,4,5-tetracarboxylic acid (btcH) and piperazine (pipz). This compound is composed of an anionic complex, [Zn(hypydc)(btc)], protonated piperazine as a counter-ion, (pipzH) and one uncoordinated water molecule. The three donor atoms of the (hypydc) and two donor atoms of bridged (btc) ligands form a distorted square pyramid arrangement around the Zn center. In the crystal structure of the title compound, a wide range of non-covalent interactions consisting of hydrogen bonding (of the types of O-H···O, N-H···O and C-H···O with D···A ranging from 2.630(2) to 3.347(3) Å, ion pairing and C-O···π stacking interactions connect the various components into a supramolecular structure. The quaternary complex system including of hypydcH-btcH-pipz and Zn ion, has been investigated. The stoichiometry and stability constants of binary complexes including each of ligands (hypydcH, btcH, pipz) in presence of Zn ion, ternary complexes including each two of three ligands (hypydcH-btcH, hypydcH-pipz, btcH-pipz) in presence of metal ion and finally quaternary systems including three ligands (hypydcH-btcH-pipz) and Zn ion were calculated in aqueous solutions by potentiometric pH titration method. Graphical Abstract: A novel polymeric mixed-ligand zinc(II) complex, {(pipzH)[Zn(hypydc)(btc)]·HO} containing 4-hydroxypyridine-2,6-dicarboxylic acid, benzene-1,2,4,5-tetracarboxylic acid and piperazine was synthesized and characterized.[Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

The synthesis of the new MOF Cu-URJC-8, containing two different organic ligands, 2-aminoterephtalic acid and 4,4-bipyridyl, is reported in this work. Cu-URJC-8 shows a pillared-layer structure consisting of [Cu 2 (-CO 2) 4 (-N) 2 ] paddlewheel secondary building units, with the 4,4'-bypiridyl linkers acting as pillars in the two-fold interpenetrated networks, which provides a robust structure to the material. Cu-URJC-8 presents Lewis acid and basic sites, constituted by Cu2+ and -NH 2 groups, respectively, and it is chemically stable in different commonly used organic solvents. This new material shows a CO 2 uptake of 1.59 and 1.07 mmol/g at 25 and 45 °C, respectively, and a Q st value of 27 kJ/mol, higher than those observed for other reported MOFs with higher textural properties, possibly due to the presence of amino groups in the MOF structure. Its catalytic activity in the cycloaddition reaction of epichlorohydrin and CO 2 was evaluated under various conditions and the best performance (90 conversion and 99% selectivity) was achieved when using 1% mol of catalyst, 4% mol of co-catalyst, 12 bar of carbon dioxide pressure, and room temperature. When different epoxides with bulkier radical groups are used as substrates, the epoxide conversion decreases, evidencing steric hindrances for diffusion inside cavities of Cu-URJC-8. Finally, Cu-URJC-8 has a high stability, keeping its structural integrity and catalytic activity after successive CO 2 cycloaddition reaction cycles. These results show that Cu-URJC-8 is a promising catalyst for CO 2 revalorization. [Display omitted] • Cu-URJC-8 is constituted by copper, 2-aminoterephtallic acid and 4,4'-bipyridyl. • Cu-URJC-8 is a suitable heterogeneous catalyst for CO 2 cycloaddition. • Cu-URJC-8 boosts high epoxide conversion and high selectivity to cyclic carbonates. • Cu-URJC-8 shows outstanding stability and after successive catalytic cycles. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel sensor array for the classification and quantification of seven metals. • Mixed-ligand nanoparticles are shown to have great potential as array receptors. • A novel, simple, "classification trajectories" method is used for metal recognition. Sensor arrays use pattern recognition for the identification and quantification of analytes. In the presented work, a gold nanoparticle (GNP) based optical sensor array was employed to classify and quantify seven toxic metals (arsenic, barium, cadmium, cerium, chromium, lead, and mercury). The sensor array receptors were GNPs functionalized by mercaptoundecanoic acid, 2-mercaptoethanesulfonate, and a 1:1 mixture of the two ligands. The mixed-ligand particle responds to the same analytes as the mono-ligand particles but in a distinctive way. This behavior demonstrates the high potential of mixed-ligand particles in the fabrication of sensor array receptors. The responses of the GNPs to different concentrations of the seven metal ions were analyzed, and a unique "classification trajectory" was produced for every metal. Samples of different metal concentrations were then measured and identified using the "classification trajectories". Once sample composition has been identified, a PLSR model, produced from the concatenated sensor array spectra of four calibration samples for each nanoparticle, was used to determine the metal concentration. [ABSTRACT FROM AUTHOR]

Abstract: Two new mixed-ligands Cu(II) complexes, [Cu(hfipbb)(2,2′-bipy)(H2O)2]n (1) and [Cu2(hfipbb)2-(4,4′-bipy)(H2O)]n (2) (H2hfipbb=4,4′-(hexafluoroisopropylidene)bis(benzoic acid)), were prepared, which both show different 2D networks and the antiferromagnetic interactions between the adjacent Cu(II) ions as well as photocatalytic degradation activity for dye degradation. [Copyright &y& Elsevier]

Abstract: ZIF-78 is a prototypical mixed-ligand compound among metal–organic frameworks (MOFs), with the composition of divalent zinc cations bridging by 2-nitroimidazolate (nIm) and 5-nitrobenzimidazolate (nbIm) anions. ZIF-78 belongs to hexagonal space group (P63/mmc) with a GME topology. Owing to the anisotropic pore structure and good affinity to CO2, ZIF-78 has potential applications in adsorption and separation fields. Herein, morphological control of ZIF-78 crystals was achieved via solvothermal synthesis. XRD, SEM, NMR, and adsorption characterizations were performed to study the crystalline phase, morphology, composition and adsorption behavior of obtained crystals, respectively. ZIF-78 micro-crystals with shape of the hexagonal rods were prepared with the assistance of triethylamine. The size and the aspect ratios of ZIF-78 microrods were manipulated from the “slender” to the “squat” via varying the nutrient concentration, the ligand concentration or relative molar ratio of nIm to nbIm. [Copyright &y& Elsevier]

Abstract: A novel 3D layer-pillared metal-organic framework of [Cd3(IDC)(BDC)1.5(H2O)] n (1), (H3IDC=imidazole-4,5-dicarboxylic acid, H2BDC=1,4-benzenedicarboxylic acid) was obtained by hydrothermal reaction, which contains rare planar hexnuclear Cd(II) cluster structural units and represents an unprecedented trinodal (4,5,14)-connected topology network. Furthermore, the thermal stability and luminescent property of 1 have also been examined. [Copyright &y& Elsevier]

Abstract: Four new cadmium(II) and zinc(II) coordination polymers {[Zn(btrp)(SIP)][Zn0.5(H2O)3]} n (1), {[Cd1.5(btrp)(SIP)(H2O)2]·2H2O} n (2), {[Cd1.5(btrb)(SIP)(H2O)3]·2H2O} n (3), {[Zn1.5(btrb)1.5(SIP)(H2O)2]·2H2O} n (4) (btrp=1,3-bis(1,2,4-triazol-1-yl)propane, btrb=1,3-bis(1,2,4-triazol-1-yl)butane, NaH2SIP=5-sulfoisophthalic acid monosodium salt) have been synthesized under hydrothermal conditions and structurally characterized. Compound 1 possesses an infinite 1D ladder-like chain structure with [Zn(H2O)6]2+ trapped in the pores, which is further interconnected by π⋯π interactions to lead to a 2D supramolecular architecture. Compounds 2 and 3 features two similar 2D layer structures, and the resulting 2D structures are interconnected by hydrogen-bond interactions to lead to 3D supramolecular architectures. Compound 4 is a 2D parallel ladder structure, and through the interpenetrating btrb ligand, it constructs into 3D architectures. Luminescence analyses were performed on all the four compounds, which show strong fluorescent emissions in the solid state at room temperature. [Copyright &y& Elsevier]

Abstract: Three new coordination compounds, {[Zn(btrp)(ip)]∙2H2O}n (1), {[Zn(btrp)(hip)]∙2H2O}n ( 2 ), and {[Zn1.5(btrp)(btc)(H2O)]∙H2O}n ( 3 ) (btrp=1,3-bis(1,2,4-triazol-1-yl)propane, H2ip=isophthalate, H2hip=5-hydroxy isophthalate, H3btc=benzene-1,3,5-tricarboxylic acid) have been prepared via solvothermal method and characterized by single crystal X-ray diffraction and elemental analysis. 1 possesses 2D (4. 4) net framewok. 2 is also a 2D infinite layer framework, and the resulting 2D structure is interconnected by hydrogen-bond and π…π interactions to lead to a 3D supramolecular architecture. 3 exhibits a novel 2D framework with three nonequivalent points, {5.62}{52.6}{54.82}. The fluorescence properties of 1–3 have been studied at room temperature. [ABSTRACT FROM AUTHOR]

Two mixed-ligand complexes of copper(II) with 1,10-phenanthroline and halides [Cu(phen)2Cl]Cl.6.5H2O (1) and [Cu(phen)2 Br]Br (2), have been synthesized and characterized by microanalysis, spectroscopic, magnetic and single-crystal X-ray diffraction studies. The two complexes are isostructural in which the coordination geometry about the copper(II) ion is that of a trigonal bipyramid, with the central copper atom bound to one chloride (I) and one bromide (2) atom and four nitrogen atoms of the two phenanthroline ligands. The result of IR, electronic spectra, electron spin resonance (ESR) and magnetic measurements are discussed. [ABSTRACT FROM AUTHOR]

Four new coordination compounds, [Zn(dba)(bpy)] n (1), {[Zn(dba)(phen)]·2H2O} n (2), [Cd(dba)(bpy)(H2O)2] (3) and [Cd2(dba)2(phen)2] n (4) (H2dba = 2,5-dihydroxy-p-benzenediacetic acid, bpy = 2,2′-bipyridine, phen = 1,10-phenanthroline) have been prepared via solvothermal method and characterized by single-crystal X-ray diffraction, infrared spectroscopy, elemental analysis and powder X-ray diffraction. 1 and 2 possess 1D infinite chain structures. Complex 3 exhibits a mononuclear structure. Complex 4 owns binuclear symmetry units, which were bridged via the dba ligands forming a 2D framework. The fluorescence properties of 1–4 have been studied. [ABSTRACT FROM AUTHOR]

Abstract: Experimental and theoretical results on the novel [Pd(Me2pipdt)(dmit)] complex (1) based on the push Me2pipdt (1,4-dimethyl-piperazine-3,2-dithione) and pull dmit (1,3-dithiolo-2-thione-4,5-dithiolato), show that an unbalanced electron distribution at the dithiolene core occurs. The presence of a solvatochromic absorption at low energy, shifted to higher frequency when compared to the corresponding nickel case, points out that these complexes are potential second-order non-linear chromophores, whose properties are tunable with the metal. [Copyright &y& Elsevier]

This work deals with the synthesis and spectroscopic characterization of novel complexes involving the coordination of croconate (C 5 O 5)2- and 5,5′-dimethyl-2,2′-bipyridyl (DmBpy) ligands to the transition metal ions Co2+ and Cu2+. Two complexes involving the croconate species with the DmBpy ligand were obtained. The complex [Cu(C 5 O 5)(DmBpy)(H 2 O)].H 2 O (1) crystallizes in a monoclinic system, belonging to the P21/c space group and Z equal to four, whereas[Co(C 5 O 5)(DmBpy)(H 2 O) 2 (2) crystallizes in a triclinic system and belonging to the P-1 space group and Z equal to four. The Cu(II) complex presents a slightly distorted square base pyramid geometry, presenting a water molecule at the vertical position, whereas Co(II) compound shows an octahedral geometry with two water molecules at the vertices. In both compounds croconate ions act as a building block, and the nitrogenous ligand is the spacer agent, giving rise to the 3D structure. The vibrational analysis (Raman and infrared) supports the crystallographic data, and several band markers are identified in order to understand the supramolecular interactions, such as the stretching modes ν CC /ν CN at 1600 and 1498 cm−1, respectively, shifted by the coordination to higher wavenumbers in both compounds (1604 and 1507 cm−1, and 1604 and 1508 cm−1, for (1) and (2) respectively), thus strongly corroborating the coordination of the ligand to the metal site through the nitrogen atoms present in the pyridine moiety. On the other hand, the band at 1718 cm−1, assigned to the (CO) stretching mode from croconate ion, can be used as the main band marker, due to the observed shift caused by the coordination to the metal center. [ABSTRACT FROM AUTHOR]