Xiaoju Li

[Zn2(H2O)3(2,2′-bipy)2(btc)][Zn(H2O)(2,2′-bipy)(btc)] ·8H2O: a novel zinc–carboxylate complex consisting of independently cationic and anionic chains

A novel zinc complex, [Zn 2 (H 2 O) 3 (2,2 ′ -bipy) 2 (btc)][Zn(H 2 O)(2, 2 ′ -bipy)(btc)]·8H 2 O ( 1 ), (H 3 btc=1,3,5- benzenetricarboxylic acid, 2,2 ′ -bipy=2,2 ′ -bipyridine) has been prepared by hydrothermal reaction of H 3 btc, Zn(CH 3 CO 2 ) 2 ·2H 2 O and 2,2 ′ -bipyridine at 180 °C and characterized by single-crystal X-ray diffraction analysis. Complex 1 consists of independently cationic and anionic chains. The hydrogen bonding interactions between chains extend 1 into a two-dimensional supramolecular architecture.

Imidazolium-Based Porous Organic Polymers: Anion Exchange-Driven Capture and Luminescent Probe of Cr2O72–

A series of imidazolium-based porous organic polymers (POP-Ims) was synthesized through Yamamoto reaction of 1,3-bis(4-bromophenyl)imidazolium bromide and tetrakis(4-bromophenyl)ethylene. Porosities and hydrophilicity of such polymers may be well tuned by varying the ratios of two monomers. POP-Im with the highest density of imidazolium moiety (POP-Im1) exhibits the best dispersity in water and the highest efficiency in removing Cr2O7(2-). The capture capacity of 171.99 mg g(-1) and the removal efficiency of 87.9% were achieved using an equivalent amount of POP-Im1 within 5 min. However, no Cr2O7(2-) capture was observed using nonionic analogue despite its large surface area and abundant pores, suggesting that anion exchange is the driving force for the removal of Cr2O7(2-). POP-Im1 also displays excellent enrichment ability and remarkable selectivity in capturing Cr2O7(2-). Cr(VI) in acid electroplating wastewater can be removed completely using excess POP-Im1. In addition, POP-Im1 can serve as a luminescent probe for Cr2O7(2-) due to the incorporation of luminescent tetraphenylethene moiety.

Isomer separation, conformation control of flexible cyclohexanedicarboxylate ligand in cadmium complexesElectronic supplementary information (ESI) available: NMR spectra for chdcH2 under different conditions, XRPD patterns and the ??? stacking information for the two complexes. See http://www.rsc.org/suppdata/cc/b4/b407405j/

Two 2D cadmium coordination polymers have been prepared using flexible 1,4-cyclohexanedicarboxylic acid (chdcH2) under hydrothermal condition, the conformations of chdcH2 were separated completely in the synthetic reactions.

Gold nanoparticles supported by imidazolium-based porous organic polymers for nitroarene reduction

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.

Syntheses and characterizations of six Co(II) and Mn(II) coordination polymers based on amino-substituted 5-aminoisophthalate and flexible bis(imidazolyl) ligands

Six Co(II) and Mn(II) coordination polymers, [Co(BIMB)(AIP)]n (1), [Co(BIMB)0.5(H2O)(AIP)]n (2), [Co(BMIB)0.5(AIP)]n·(H2O)n (3), [Mn2(BIMB)2(AIP)2]n (4), [Mn(BMIB)(H2O)2(AIP)]n·(DMF)n (5) and [Mn(BIMB)0.5(PAIP)]n·(H2O)n (6) (AIP = 5-aminoisophthalate, PAIP = 5-(2-pyridylmethyl)aminoisophthalate, BIMB = 1,4-bis(imidazol-1-yl-methyl)benzene and BMIB = 1,4-bis(2-methylimidazol-1-yl-methyl)benzene), were synthesized and characterized. AIP in 1–5 originates from the in situ deprotection of 5-(4-oxopentan-2-ylideneamino)isophthalic acid in the synthetic process. Complex 1 is a 2D → 3D interdigitating network, and hydrogen bonds between the uncoordinated amino and carboxylate oxygen atoms of the adjacent layers further stabilize the 3-D framework. Different from AIP in 1, the amino of AIP in 2 and 3 participates in coordination, μ3-bridged AIP connects Co(II) to a 1-D double chain and 2-D layer, respectively, and the subsequent bridge by BIMB and BMIB results in the formation of a 2-D layer and 2-D pillared-bilayer network, respectively. Notably, the coordinated water in complex 2 may be reversibly removed with a concomitant color change and maintenance of the original structural framework. The amino of AIP in 4 and 5 is not involved in coordination, but AIP and BIMB, which has an anti-conformation, in 4 link Mn(II) to a 2-D layer consisting of dinuclear Mn(II)-carboxylate units, while AIP and BMIB, which has an gauche conformation, in 5 links Mn(II) ions to a 1-D chain. Complex 6 is a 3-D pillared-layer structure. It should be mentioned that extensive hydrogen bonds are formed in complexes 1–6. The magnetic study of complex 4 shows that there is a dominant antiferromagnetic coupling above 40 K, while a weak ferromagnetic order is caused by spin-canting at lower temperatures.

Effects of hydroxy substituents on Cu(II) coordination polymers based on 5-hydroxyisophthalate derivatives and 1,4-bis(2-methylimidazol-1-yl)benzene

In order to systematically investigate the effects of 5-positioned substituents in isophthalates on the structures and properties of coordination polymers, six Cu(II) coordination polymers, [Cu2(bmib)(HO–ip)2]n (1), [Cu4(bmib)(OH)2(MeO–ip)3]n (2), [Cu(bmib)(MeO–ip)]n·(DMF)2n·(H2O)2n (3), [Cu(bmib)0.5(H2O)(EtO–ip)]n·(DMF)0.5n (4), [Cu(bmib)(PrO–ip)]n·(H2O)2.5n (5) and [Cu(bmib)(BnO–ip)]n·(DMF)n (6) have been synthesized by hydrothermal reaction of 5-hydroxyisophthalate derivatives (RO–ip, R = H, Me, Et, Pr and Bn), 1,4-bis(2-methylimidazol-1-yl)benzene (bmib) and Cu(NO3)2·3H2O. Their structures have been confirmed by single crystal X-ray diffraction analyses, IR spectroscopy, TGA and elementary analyses. In 1, μ3-bridged HO–ip links dinuclear Cu(II)–carboxylate units into a 2-D layer, which is further pillared by bmib to generate a two-fold interpenetrating 3-D network. However, μ4-bridged MeO–ip in 2 connects Cu(II) into a 3-D coordination network consisting of tetranuclear Cu(II)–carboxylate units, bmib serves as a void filler by bridging between tetranuclear units. In 3, bis-chelating MeO–ip and bmib link Cu(II) into a 2-D layer, which is packed in an eclipsed pattern. In 4–6, Cu(II) ions are in a distorted square-planar geometry, and carboxylate ligands adopt a bis-monodentate bridging mode and connect the Cu(II) ions into a charge-neutral chain. A pair of such chains in 4 is pillared by bmib to form a pillared-bichain structure, while bmib in 5 and 6 bridges the adjacent chains, resulting in the formation of different 2-D layers. The packing of the 2-D layers in 5 and 6 generates 1-D channels containing guest molecules, which are confirmed by their TGA analyses. The temperature-dependent magnetic analyses show that the dinuclear and tetranuclear Cu(II) units make up the basic magnetic unit of 1 and 2, respectively, and they show an antiferromagnetic interaction.

Synthesis, crystal structure and magnetic property of a three-dimensional manganese(II) complex

The solvothermal reaction of MnCl2·4H2O, H2asp and CH3ONa gave rise to a new manganese(II) complex, {[Mn(asp)(H2O)]·(H2O)2} n (1) (H2asp = 5-aminoisophthalic acid). Single-crystal X-ray diffraction analysis reveals that complex 1 is a three-dimensional consisting of two-dimensional layers extended by hydrogen bonding interactions. The two-dimensional layer contains 8-, 14-, and 16-membered rings. A variable temperature magnetic measurement of 1 displays weak antiferromagnetic behavior.