Novel ionic surface imprinting technology: design and application for selectively recognizing heavy metal ions.

Traditional bulk polymerization imprinted technology and existing surface imprinted technology have some congenital defects. Therefore, it is necessary to design more efficient surface imprinted technology. In this paper, novel surface imprinting technology with higher imprinting efficiency is well designed. It fully realizes the synchronization of polymer crosslinking and template imprinting. Then the surface imprinted polymers (SIPs) are synthesized using metal ions as a template. The physicochemical characteristics of the SIPs are characterized by scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) studies, Fourier transform infrared spectroscopy (FTIR) and elemental analysis. The adsorption performances and recognition selectivity of the SIPs towards the template are investigated by a batch method. The experimental results show that the SIPs possess excellent adsorption ability and selectivity towards the template. The selectivity coefficients of the SIPs prepared in this study are higher than those of IIPs prepared by other imprinting methods. The adsorption process could be well described by the Lagergren-first-order model and Langmuir monolayer chemical adsorption. The SIPs have good chemical stability and reusability. Consecutive adsorption-desorption experiments show that the exhausted SIPs could be effectively regenerated, and the regenerated SIPs could be reused without a significant reduction in adsorption capacity or selectivity coefficient.

A cobalt(ii) chain based on pymca generated in situ from the hydrolysis of 2-cyanopyrimidine: spin canting and magnetic relaxation.

A one-dimensional (1D) coordination polymer, [{Co2(pymca)2·(H2O)4}SO4·2H2O] n (1) (pymca = 2-carboxypyrimidine), was solvothermally synthesized via the reaction of 2-cyanopyrimidine and Co(SCN)2. A bidentate pymca ligand was formed in situ by the hydrolysis of 2-cyanopyrimidine. Furthermore, in this study, the magnetic properties of complex 1 were investigated in detail. The results indicated that complex 1 showed a single-chain magnet (SCM) behavior below ca. 3 K. The energy barrier (Δτ 1/k B) and preexponential factor (τ 0) of SCM were 31.2 K and 5.4 × 10-9 s, respectively.

Important Role of Intermolecular Interaction in Cobalt(II) Single-Ion Magnet from Single Slow Relaxation to Double Slow Relaxation.

Two cobalt complexes with similar structures were synthesized using quinoline-2-carboxylic acid (HL) as the ligand. Both complexes are six-coordinated in antitriangular prism coordination geometries. There are one and four molecule units per cell for 1 and 2, respectively, with nearest Co-Co distances of 7.129 and 5.855 Å, respectively, which lead to their intermolecular interactions zj'. Both complexes are field-induced single-ion magnets. Complex 1 shows single slow relaxation under Hdc = 1.5 kOe attributed to the moment reversal, while complex 2 shows double slow relaxation resulting from intermolecular dipolar interaction and moment reversal, respectively.

A novel 3D Cu(I) coordination polymer based on Cu6Br2 and Cu2(CN)2 SBUs: in situ ligand formation and use as a naked-eye colorimetric sensor for NB and 2-NT.

A novel coordination polymer with the chemical formula [Cu4Br(CN)(mtz)2]n (mtz = 5-methyl tetrazole) (), has been synthesized under solvothermal conditions and characterized by elemental analysis, infrared (IR) spectroscopy, thermal gravimetric analysis, powder X-ray diffraction and single-crystal X-ray diffraction. Interestingly, the Cu(i), CN(-) and mtz(-) in compound are all generated from an in situ translation of the original precursors: Cu(2+), acetonitrile and 1-methyl-5-mercapto-1,2,3,4-tetrazole (Hmnt). The in situ ring-to-ring conversion of Hmnt into mtz(-) was found for the first time. Structural analysis reveals that compound is a novel 3D tetrazole-based Cu(i) coordination polymer, containing both metal halide cluster Cu6Br2 and metal pseudohalide cluster Cu2(CN)2 secondary building units (SBUs), which shows an unprecedented (3,6,10)-connected topology. Notably, a pseudo-porphyrin structure with 16-membered rings constructed by four mtz(-) anions and four copper(i) ions was observed in compound . The fluorescence properties of compound were investigated in the solid state and in various solvent emulsions, the results show that compound is a highly sensitive naked-eye colorimetric sensor for NB and 2-NT (NB = nitrobenzene and 2-NT = 2-nitrotoluene).

Four Hybrid Materials Based on Preyssler P5W30 Polyoxometalate and First-Row Transition-Metal Complex.

Four Preyssler P5W30 based inorganic-organic hybrids, formulated as {[Cu12(pbtz)2(Hpbtz)2(OH)4(H2O)16][Na(H2O)P5W30O110]}·16H2O (1; H2pbtz = 5'-(pyridin-2-yl)-1H,2'H-3,3'-bi(1,2,4-triazole)), {[Cu10(ttbz)2(Httbz)4(OH)6(H2O)8][K(H2O)H2P5W30O110]}·30H2O (2; Httbz = 1-(tetrazo-5-yl)-4-(triazo-1-yl)benzene), {[Ni6(bpz)6(H2O)16][Na(H2O)H2P5W30O110]}·36H2O (3; bpz = 3,3',5,5'-tetramethyl-4,4-bipyrazole), {[Co4(bpz)6(H2O)9][K(H2O)H6P5W30O110]}·46H2O (4), have been isolated and structurally identified via microanalysis, thermogravimetry (TG), infrared (IR) spectroscopy, and X-ray single-crystal diffraction. Compound 1 exhibits a 3D binodal (3,6)-connected ant framework composed of dodeca-supported P5W30 polyoxometalate (POM) clusters and discrete [Cu6(pbtz)(Hpbtz)(OH)2(H2O)8] subunits. Compound 2 is a pillared-layer 3D network constructed from [Cu5(ttbz)(Httbz)2(OH)3(H2O)4] sheets pillared by individual P5W30 clusters. Compound 3 contains octa-supporting P5W30 POM clusters and novel [Ni6(bpz)6] crown-like metallamacrocycles, which construct a (4,4)-connected pts network. Compound 4 displays a complicated 3D (5,5)-connected {4(5)·6(4)·8}{4(5)·6(5)} network built by pentasupporting P5W30 POM clusters and discrete [Co4(bpz)6(H2O)9] subunits. In 1-4, the unified features are the Preyssler-type [P5W30O110] POM as the fundamental building block, which supports the transition-metal compounds with different modes to give the resultant diverse networks. The magnetism studies indicated antiferromagnetically coupled systems for the hexa- and pentanuclear Cu(II) units in 1 and 2, respectively. The electrochemical properties demonstrate that all compounds have electrocatalytic abilities toward the reduction of hydrogen peroxide. Furthermore, the catalytic activities of 1 in the cyanosilylation of aldehydes reaction have been investigated.

Solvent-controlled three families of Zn(II) coordination compounds: synthesis, crystal structure, solvent-induced structural transformation, supramolecular isomerism and photoluminescence.

This work reports the assembly, topological structure, supramolecular isomerism and luminescence of three solvent-controlled families of coordination compounds, [Zn(bpz)2(H2O)3·2Hpta] (1), [Zn(bpz)(pta)]n (2), [Zn(bpz)(tpa)(H2O)]n (3), [Zn(bpz)(tpa)·4H2O]n (4), and [Zn(bpz)(npa)·H2O]n (5 and 6) (bpz = 3,3',5,5'-tetramethyl-4,4'-bipyrazole, H2pta = phthalic acid, H2tpa = terephthalic acid, H2npa = 4-nitrophthalic acid). The six transition metal compounds reported in this study were definitely characterized by X-ray crystallography to reveal how networks with different topologies are constructed around the same four-connected metal centers. Compound 1 is a 0D discrete molecule, in which Zn(II) is in a trigonal bipyramidal coordination geometry, whereas the guest Hpta(-) as counteranion is hydrogen-bonded with the [Zn(bpz)2(H2O)3]. In compound 2, the Zn(II) center is linked by two bpz and two pta; thus, a 4-connected dia network with the point symbol {6(6)} is formed. In 3, the Zn(II) center is six-coordinated, but in fact it is also a 4-connected node in the whole network due to the terminal aqua ligand and bidentate chelating carboxylate group thus, the resultant network has a 4-connected cds topology with the point symbol {6(5)·8}. Compound 4 exhibits a chiral two-fold interpenetrated 4-connected qtz network with the point symbol {6(4)·8(2)}. Compounds 5 and 6 are a pair of genuine supramolecular isomers with identical 4-connected dia topology. The three families of compounds, namely, 1/2, 3/4, and 5/6, are structurally controlled by the solvent systems H2O/CH3OH-H2O, H2O/DMF-CH3OH, and CH3OH-H2O/CH3CN-H2O, respectively. Except for the discrete molecule 1, the other five compounds have the same 4-connected coordination networks, but with different topologies ranging from dia (2, 5, 6), cds (3) to qtz (4), suggesting the important influences that the linkage orientations of the ligand and different geometries of the 4-connected node exert in self-assembly. Interestingly, discrete 1 can be irreversibly transformed from a 0D discrete molecule to an infinite 3D structure (2) by heating it in CH3OH-H2O solvent, indicating a solvent-induced structural transformation. In addition, results about thermal stabilities and photoluminescence spectra are also discussed in detail.

Simultaneous encapsulation of an infinite T4(0)A(0)6(0) water tape and discrete water hexamers in a hydrogen-bonded Ag(I) supramolecular framework.

Self-assembly of Ag2O, 1,4-bis(pyrid-4-yl)benzene (dpb) and 1,3-benzenedicarboxylic acid (H2bdc) resulted in a one-dimensional mixed-ligand Ag(I) coordination polymer [Ag2(dpb)2(bdc)·9H2O]n (1), in which infinite 1D T4(0)A(0)6(0) water tapes and discrete water hexamers were simultaneously encapsulated. Chair-like water hexamers and D2h water tetramers with two dangling water molecules were alternately hydrogen-bonded into the unprecedented 1D T4(0)A(0)6(0) water tape. Additionally, results on the thermal stability, UV-Vis absorption and photoluminescence spectra of 1 were discussed.

Phase transfer catalyst supported, room-temperature biphasic synthesis: a facile approach to the synthesis of coordination polymers.

A facile approach, named phase transfer catalyst supported, room temperature biphasic synthesis, has been developed to synthesize a new type of coordination polymers. Compared to the traditional biphasic solvothermal synthesis that was run at high temperature (100-200 °C), the new approach introduced here can be operated under a mild condition (room temperature) with the support of phase transfer catalyst. With the application of this new approach, two copper coordination complexes with 1D metal-organic nanotube and 1D coordination polymer containing large water clusters have been successfully synthesized and characterized. Furthermore, the synthetic approach presented here can be extended to synthesize other coordination polymers, including porous lanthanide-organic frameworks.

Bis(2-{5-[(2-carb-oxy-phen-yl)sulfanylmeth-yl]-2,4-dimethyl-benzyl-sulfan-yl}benzoato-κO,O')bis-(pyridine-κN)iron(II).

The title compound, [Fe(C(24)H(21)O(4)S(2))(2)(C(5)H(5)N)(2)], has 2 symmetry. The Fe(II) cation is located on a twofold rotation axis and is O,O'-chelated by two 2-{5-[(2-carb-oxy-phen-yl)sulfanylmeth-yl]-2,4-dimethyl-benzyl-sulfan-yl}benzoate anions and further coordinated by two pyridine ligands in a distorted octa-hedral geometry. In the anion, the terminal benzene rings are oriented at dihedral angles of 63.81 (14) and 84.50 (14)° with respect to the central benzene ring. Inter-molecular O-H⋯O and C-H⋯O hydrogen bonding is present in the crystal structure.