Co-reporter:Hong Zhong, Yanqing Su, Caiyan Cui, Feng Zhou, Xiaoju Li, and Ruihu Wang
ACS Sustainable Chemistry & Engineering September 5, 2017 Volume 5(Issue 9) pp:8061-8061
Publication Date(Web):August 15, 2017
DOI:10.1021/acssuschemeng.7b01675
Facile hydrogen generation from formic acid (FA) is a promising way of hydrogen storage and release in the fuel-cell-based hydrogen economy; the development of efficient heterogeneous catalyst systems for ultrapure H2 generation from FA in the absence of additives remains a major challenge. Herein, we present a prefunctionalized porous organic polymer (POP) containing 2,6-bis(1,2,3-triazol-4-yl)pyridyl (BTP) units and carboxylate groups. The terdentate BTP and hydrophilic carboxylate are homogeneously incorporated into the host framework of the POP. BTP units with strong chelating ability can effectively stabilize palladium nanoparticles for heterogeneous dehydrogenation of FA, whereas carboxylate not only increases polarity and dispersibility of the catalytic system in aqueous solutions but also functions as basic sites to facilitate the O–H bond dissociation. The catalytic system shows high catalytic activity, excellent stability and superior recyclability in H2 generation from aqueous FA without any additives.Keywords: Additive free; Hydrogen generation; Palladium nanoparticles; Porous organic polymers; Sustainable Chemistry;
Co-reporter:Yanqing Su, Yangxin Wang, Xiaoju Li, Xinxiong Li, and Ruihu Wang
ACS Applied Materials & Interfaces 2016 Volume 8(Issue 29) pp:18904-18911
Publication Date(Web):July 1, 2016
DOI:10.1021/acsami.6b05918
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 Cr2O72–. 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 Cr2O72– 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 Cr2O72–. POP-Im1 also displays excellent enrichment ability and remarkable selectivity in capturing Cr2O72–. 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 Cr2O72– due to the incorporation of luminescent tetraphenylethene moiety.
Co-reporter:Xiaofei Sun, Yanqing Su, Hui Pan, Xiaoju Li
Inorganica Chimica Acta 2016 Volume 442() pp:187-194
Publication Date(Web):1 March 2016
DOI:10.1016/j.ica.2015.12.010
•Seven coordination polymers based on 5-acetamidoisophthalate (AcAIP) and flexible bis(imidazolyl) ligands were presented.•The competitive interaction of bis(imidazolyl) ligands results in uncoordination of acetamido in AcAIP.•The orientation of imidazolyl groups at aromatic rings shows important effects on the structures of coordination polymers.•The anti and gauche configurations of bis(imidazolyl) ligands are shown.Seven Zn(II) and Co(II) coordination polymers based on 5-acetamidoisophthalate (AcAIP) and flexible bis(imidazolyl) ligands, [Zn(H2O)0.5(AcAIP)]n (1), [Zn(AcAIP)(o-BIMB)]n·3nH2O (2), [Co(AcAIP)(o-BIMB)]n·3nH2O (3), [Zn(AcAIP)(m-BIMB)]n·3nH2O (4), [Co(AcAIP)(m-BIMB)]n·3nH2O (5), [Zn(AcAIP)(p-BIMB)]n (6) and [Co(AcAIP)(p-BIMB)]n (7) (o-BIMB = 1,2-bis(imidazol-1-yl-methyl)benzene, m-BIMB = 1,3-bis(imidazol-1-yl-methyl)benzene and p-BIMB = 1,4-bis(imidazol-1-yl-methyl)benzene), were synthesized and well characterized. In complex 1, AcAIP serves as a μ4-bridge through μ2,η2-carboxylate, monodentate carboxylate and acetamido, and connects Zn(II) ions into a 3-D network, while acetamido group of AcAIP in 2–7 is not involved in coordination with metal ions owing to the presence of bis(imidazolyl) ligands. Notably, AcAIP in 2–6 bridges two metal ions through two monodentate carboxylate groups. AcAIP in 2–5 connects Zn(II) and Co(II) ions into 1-D chain, subsequent bridge by o-BIMB generates a 2-D corrugated layer, while m-BIMB connects two intra-chained metal ions to form [Zn2(AcAIP)(m-BIMB)] macrocycles. Interestingly, AcAIP in 6 links two Zn(II) ions into a 16-membered [Zn2(AcAIP)2] macrocycle, and subsequent bridge by anti-conformationed p-BIMB forms a 2-D layer. However, two carboxylate groups of AcAIP in 7 function in μ2,η2-bridging and chelating modes, AcAIP and gauche-conformationed p-BIMB bridge Co(II) ions to form a twofold interpenetrating framework consisting of dinuclear Co(II)-carboxylate units. Magnetic analysis of complex 7 shows that the existence of antiferromagnetic interactions. Fluorescent properties of Zn(II) coordination polymers in solid state were also investigated.Seven Zn(II) and Co(II) coordination polymers based on 5-acetamidoisophthalate were presented, the introduction of bis(imidazol-1-yl-methyl)benzene ligands results in uncoordination of acetamido group owing to their competitive coordination. The orientation of bis(imidazolyl) groups at aromatic rings shows important effects on the structures of coordination polymers.
Co-reporter:Xiaoju Li, Xiaofei Sun, Xinxiong Li, Zhihua Fu, Yanqing Su, and Gang Xu
Crystal Growth & Design 2015 Volume 15(Issue 9) pp:4543-4548
Publication Date(Web):August 10, 2015
DOI:10.1021/acs.cgd.5b00799
Two porous 3-D anionic metal–organic frameworks (MOFs) containing protonated bmib, [Cd2(btc)2(H2O)2]n·n(H2bmib)·6n(H2O) (1) and [Cd4(cpip)2(Hcpip)2]n·n(H2bmib)·n(H2O) (2), have been prepared by hydrothermal reactions of Cd(NO3)2·4H2O, 1,4-bis(2-methylimidazol-1′-yl)butane (bmib) with 1,3,5-benzenetricarboxylic acid (H3btc) and 5-(4-carboxyphenoxy)isophthalic acid (H3cpip), respectively. Complexes 1 and 2 are 3-D anionic frameworks containing 1-D channels and consisting of tetranuclear Cd(II)-carboxylate units, respectively. H2bmib and lattice water molecules are located in their void spaces and form extensive hydrogen bonds and C–H···π interaction with the anionic frameworks. TGA studies and XRD patterns show the anionic frameworks of 1 and 2 are intact after the removal of lattice water molecules. The luminescent emission of 1 and 2 shows an obvious red shift in comparison with free H3btc and H3cpip, respectively. Complexes 1 and 2 possess proton conduction owing to the presence of the extensive hydrogen bonds and protonation of bmib; their proton conductivity at 333 K and 95% relative humidity are 5.4 × 10–5 and 2.2 × 10–5 S cm–1, respectively.
Co-reporter:Xiaoju Li, Zhenjiang Yu, Tena Guan, Xinxiong Li, Guangchao Ma, and Xiaofang Guo
Crystal Growth & Design 2015 Volume 15(Issue 1) pp:278-290
Publication Date(Web):November 19, 2014
DOI:10.1021/cg501327u
Eight Zn(II) coordination polymers, [Zn(EtO-ip)(bimb)]n(DMF)n (1), [Zn(PrO-ip)(bimb)0.5]n (2), [Zn2(NO2-ip)2(bimb)2]n(H2O)n (3), [Zn2(NO2-ip)2(bimb)1.5]n(H2O)n (4), [Zn(MeO-ip)(bmib)0.5]n(H2O)0.5n (5), [Zn(EtO-ip)(bmib)0.5]n (6), [Zn(PrO-ip)(bmib)]n (7), and [Zn (NO2-ip)(bmib)]n (8) (EtO-ip = 5-ethoxyisophthalate, PrO-ip = 5-propoxyisophthalate, NO2-ip = 5-nitroisophthalate, MeO-ip = 5-methoxyisophthalate, bimb = 1,4-bis(imidazol-1′-yl)butane, bmib = 1,4-bis(2-methylimidazol-1′-yl)butane), have been prepared and characterized by single-crystal X-ray diffraction analyses. In 1, bis-monodentate EtO-ip and exo-bidentate bimb connect four-coordinated Zn(II) into a corrugated 2-D layer. In 2, μ2,η2-carboxylate and monodentate carboxylate in PrO-ip bridge dinuclear Zn(II) units to generate a [Zn2(PrO-ip)4]n layer, which is further extended by bimb into a 3-D network. Interestingly, bis-monodentate NO2-ip and bimb in 3 connect four-coordinated Zn(II) into two independent 2-D layers, which are stabilized by π···π stacking interactions from phenyl rings of NO2-ip in different layers. In 4, μ3-bridged NO2-ip alternately links single Zn(II) ions and dinuclear Zn(II) units into a 1-D chain containing square-shaped cavities, which is further extended by bimb into a 2-fold interpenetrating 3-D framework. However, μ3-bridged MeO-ip and EtO-ip together with bmib in 5 and 6 link dinuclear Zn(II) units into a 2-D layer. In 7, bis-monodentate PrO-ip and bmib connect four-coordinated Zn(II) ions into a 2-D corrugated layer, while four-coordinated Zn(II) ions in 8 are linked by bis-monodentate NO2-ip and bmib into a 3-fold interpenetrating framework consisting of left- and right-handed helical chains. The thermal stability and luminescent properties of 1–8 in the solid state were investigated in detail.
Co-reporter:Xiaoju Li, Xiaofei Sun, Xinxiong Li and Xiahong Xu
New Journal of Chemistry 2015 vol. 39(Issue 9) pp:6844-6853
Publication Date(Web):16 Jun 2015
DOI:10.1039/C5NJ00706B
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.
Co-reporter: Xiaoju Li;Zhenjiang Yu; Xinxiong Li;Xiaofang Guo
Chemistry - A European Journal 2015 Volume 21( Issue 46) pp:16593-16600
Publication Date(Web):
DOI:10.1002/chem.201501029
Abstract
Reactions of 5-nitroisophthalic acid (NO2-H2ip), 1,4-bis(imidazol-1′-yl)butane (bimb), and Ni(NO3)2⋅6 H2O gave rise to four metal–organic frameworks (MOFs), [Ni2(NO2-ip)2(bimb)1.5]n (1), [Ni4(NO2-ip)3(bimb)2(OH)2(H2O)]n ⋅(CH3CH2OH)0.5 n (2), [Ni(NO2-ip)(bimb)1.5(H2O)]n⋅(H2O)n ⋅(CH3CH2OH)0.5 n (3), and [Ni(NO2-ip) (bimb)(μ-H2O)]n⋅(H2O)n (4). The metal/ligand ratio, pH value, and solvent exerted a subtle but crucial influence on the formation of complexes 1–4, which possess different visual color and crystal structures. Complex 1 exhibits a twofold interpenetrating 3D pillared bilayer framework composed of binuclear and mononuclear NiII units, whereas complex 2 is a 3D chiral network that consists of asymmetric tetranuclear NiII units. Complexes 3 and 4 are 3D layer-pillared frameworks that consist of mononuclear NiII ions and a 3D six-connected network of μ-water-bridged dinuclear NiII units, respectively. Interestingly, achiral 4 can be transformed into chiral 2 by using a solvent-mediated single-crystal-to-single-crystal process without any chiral auxiliary. Magnetic analyses of 2 and 4 show the occurrence of antiferromagnetic interactions. Complex 3 is difficult to obtain directly as a single solid phase, but it can be homogeneously formed by solvent-mediated transformations from 1, 2, and 4.
Co-reporter:Xiaoju Li;Tena Guan;Xiaofang Guo;Xinxiong Li;Zhenjiang Yu
European Journal of Inorganic Chemistry 2014 Volume 2014( Issue 13) pp:2307-2316
Publication Date(Web):
DOI:10.1002/ejic.201400092
Abstract
Four CoII and CuII complexes, namely, [Co2(ip-OH)2(dpe)]n [1; ip-OH = 5-hydroxyisophthalate, dpe = 1,2-di(4-pyridyl)ethane], [Co2(ip-OH)2(dpy)2]n(dpy)n(H2O)2n [2; dpy = 1,2-di(4-pyridyl)ethylene], [Cu2(ip-OH)2(dpe)]n (3), and [Cu2(ip-OH)2(dpy)]n (4), were hydrothermally synthesized and characterized. Single-crystal X-ray diffraction studies reveal that 1–4 consist of different dinuclear metal units, ip-OH possesses different coordination modes, and both dpe and dpy adopt anti conformations. In 1, the ip-OH ligands link dinuclear CoII units into a charge-neutral [Co2(ip-OH)2]n layer, which is further connected by pillars of dpe to generate a twofold interpenetrating 3D network. However, dinuclear CoII units in 2 are bridged by ip-OH to form a 1D [Co2(ip-OH)2]n chain, which is further connected by dpy into a 2D network consisting of the prismatic building blocks [Co8(ip-OH)8(dpy)8]. Similarly to 1, 3 and 4 are twofold interpenetrating α-Po architectures, despite the different ip-OH bridging modes and different coordination geometries of the metal ions. The dinuclear units in 1–4 are well separated by ip-OH and dpe/dpy ligands. The magnetic data of 1–3 are fitted according to the dimeric modes, and the results of the best fit indicate the existence of antiferromagnetic exchange between the metal centers in the dinuclear metal units.
Co-reporter:Xiaoju Li, Xiaofang Guo, Xiahong Xu, Guangchao Ma, Shen Lin
Inorganic Chemistry Communications 2013 Volume 27() pp:105-107
Publication Date(Web):January 2013
DOI:10.1016/j.inoche.2012.10.031
An eight-connected 3D coordination polymer consisting of water-bridged dinuclear Ni(II) units has been prepared. The complex exhibits an unprecedented non-interpenetrating framework.An eight-connected 3D coordination polymer has been synthesized and characterized. The complex is non-interpenetrating and consists of the water-bridged dinuclear Ni(II) units.Highlights► A 3D coordination polymer consisting of dinuclear Ni(II) units was prepared. ► The complex is an eight-connected network. ► The framework of the complex is non-interpenetrating.
Co-reporter:Xiaoju Li, Xiahong Xu, Daqiang Yuan and Xiulan Weng
Chemical Communications 2012 vol. 48(Issue 72) pp:9014-9016
Publication Date(Web):05 Jul 2012
DOI:10.1039/C2CC34412B
An experimental (H2O)n (n > 10) aggregate, similar to a theoretical hexagonal prismatic dodecameric water cluster structure, is characterized, the water cluster can be reversibly generated. The hydrogen bonds between the water clusters and bis(imidazolyl) ligand result in the formation of a five-fold interpenetrating six-connected supramolecular network.
Co-reporter:Xiaoju Li, Xiaofang Guo, XiuLan Weng and Shen Lin
CrystEngComm 2012 vol. 14(Issue 4) pp:1412-1418
Publication Date(Web):08 Dec 2011
DOI:10.1039/C1CE06216F
The reaction of 1,4-bis((pyridinium-4-carboxylic acid)methyl)benzene dibromide (Bpmb-2HBr), Cd(NO3)2·4H2O with 1,2-bis(imidazol-1′-yl)ethane (Bime) and 1,4-bis(imidazol-1′-yl)butane (Bimb) gave rise to two novel 2D Cd(II) coordination polymers, [Cd1.5(Bime)(Bpmb)0.5(μ-Br)Br2·DMF]n (1) and [Cd2(Bimb)2(μ-Br)2Br2]n (2), respectively, in which coordination of μ-Br− and monodentate Br− with Cd(II) generates an unprecedented trimeric [Cd3(μ-Br)2Br4] unit in 1 and a dimeric [Cd2(μ-Br)2Br2] unit in 2. In 1, gauche-Bime links the central six-coordinated Cd(II) of the trimers into a 1D double chain, anti-Bpmb further bridges the terminal four-coordinated Cd(II) of the trimers in the opposite direction to generate a 2D layer. Complex 2 is a 2D corrugated layer consisting of perpendicular left- and right-handed helical chains constructed through anti-anti-gauche-conformated Bimb bridging the neighboring six-coordinated Cd(II) of [Cd2(μ-Br)2Br2] units. The thermal stability and fluorescent properties of the two complexes have also been studied.
Co-reporter:Xiaofang Guo, Xiaoju Li, Xiulan Weng, Shen Lin
Journal of Molecular Structure 2012 Volume 1008() pp:63-68
Publication Date(Web):25 January 2012
DOI:10.1016/j.molstruc.2011.11.025
The reaction of 1,2-bis(imidazol-1′-yl)ethane (bime), 4-hydroxybenzoic acid (HO-HBC) with different metal salts in water/ethanol gave rise to three supramolecular architectures [M(HO-BC)2(H2O)2(bime)]n [M = Mn(II), Co(II) and Ni(II)]. Single crystal X-ray diffraction analysis reveals that complexes 1–3 are isomorphous and are 3D supramolecular networks. HO-BC serves as a monodentate ligand through one carboxylate oxygen atom coordinating to metal center. The extensive hydrogen bonds from HO-BC and coordination water result in the formation of 3D supramolecular networks. The gauche-conformational bime connects the neighboring metal ions into 1D chain, which is located in the large void of the 3D networks. The thermogravimetric analysis reveals that complexes 1–3 are stable before 273 °C. Magnetic analysis shows that there are no interactions between neighboring metal ions.
Co-reporter:Xiaoju Li, Yuanzhu Cai, Zhenlan Fang, Lijian Wu, Bin Wei, and Shen Lin
Crystal Growth & Design 2011 Volume 11(Issue 10) pp:4517-4524
Publication Date(Web):September 2, 2011
DOI:10.1021/cg200730k
Three two-folded interpenetrating 3D coordination polymers, [M(ip-OH)(Bimb)0.5]n [where M = Ni(II) (1), Co(II) (2), or Cu(II) (3); H2ip-OH = 5-hydroxylisophthalic acid; and Bimb =1,4-bis(imidazol-1′-yl)butane], were synthesized by hydrothermal reactions of H2ip-OH, Bimb, and MCl2 in the presence of base. Single-crystal X-ray diffraction studies reveal that 1–3 consist of dinuclear metal units, which are bridged by ip-OH to form [M(ip-OH)]n layers and are further pillared by Bimb to generate 3D α-Po networks. Bimb adopts a gauche–antigauche conformation. Both the large void in the 3D network and the hydrogen bonds between hydroxyl of ip-OH and one carboxylate oxygen atom from the other network result in the formation of two-folded interpenetrating architectures. The secondary building units in 1–3 are well separated by ip-OH and Bimb. The magnetic data of 1–3 were fitted to the dimeric modes; fitting results indicate antiferromagnetic exchange between metal centers in the dinuclear metal units.
Co-reporter:Xiaoju Li, Xiulan Weng, Ruijie Tang, Yuanmiao Lin, Zhilong Ke, Wenbiao Zhou and Rong Cao
Crystal Growth & Design 2010 Volume 10(Issue 7) pp:3228
Publication Date(Web):May 26, 2010
DOI:10.1021/cg100350b
Four helical coordination polymers, [Cd(anti-bime)(1,3-pda)]n (1), [Cd(gauche-bime)(1,4-pda)]n (2), [Co(anti-bime)(1,2-pda)]n (3), and [Co(gauche-bime)(1,4-pda)]n (4), have been solvothermally prepared by the assembly of mixed flexible ligands, bime and 1,3-H2pda, 1,4-H2pda, 1,2-H2pda with Cd(NO3)2·4H2O and Co(NO3)2·6H2O, respectively (bime = 1,2-bis(imidazol-1′-yl)ethane, 1,3-H2pda = 1,3-phenylenediacetic acid, 1,4-H2pda = 1,4-phenylenediacetic acid, 1,2-H2pda = 1,2-phenylenediacetic acid). Single-crystal X-ray diffraction analyses reveal that all of the complexes possess helical structures owing to the use of mixed flexible ligands; the conformations of flexible bime are entirely different, anti-bime occurs in 1 and 3, while gauche-bime occurs in 2 and 4. The fluorescent properties of 1 and 2 suggest that the intense broad photoluminescence emission at 387 nm for 1 and 389 nm for 2, 3, and 4 exhibit similar weak antiferromagnetic coupling between the Co2+ centers.
Co-reporter:Xiaoju Li, Xiahong Xu, Daqiang Yuan and Xiulan Weng
Chemical Communications 2012 - vol. 48(Issue 72) pp:NaN9016-9016
Publication Date(Web):2012/07/05
DOI:10.1039/C2CC34412B
An experimental (H2O)n (n > 10) aggregate, similar to a theoretical hexagonal prismatic dodecameric water cluster structure, is characterized, the water cluster can be reversibly generated. The hydrogen bonds between the water clusters and bis(imidazolyl) ligand result in the formation of a five-fold interpenetrating six-connected supramolecular network.
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