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Two unprecedented three-dimensional (3D) true coordination polymorphs, namely, [Pb2(phda)2(H2O)]n·2nH2O (1a, and 1b) (H2phda = 1,4-phenylenediacetate acid), which show distinct novel topological networks, have been successfully prepared by utilizing a kinked flexible H2phda. This work shows the first example of two different isomers reported for a flexible ligand acting as a bridge. Two unprecedented three-dimensional (3D) PbII coordination polymorphs, namely, [Pb2(phda)2(H2O)]n·2nH2O (1a, and 1b) (H2phda = 1,4-phenylenediacetate acid), which show distinct novel topological networks, have been successfully prepared by utilizing a kinked flexible H2phda. This work shows the first example of two different isomers reported for a flexible ligand acting as a bridge. [ABSTRACT FROM AUTHOR]

Twomicroporous metal–organic frameworks, [Zn2(HDDCBA)]·2DMF·2H2O (1) and [Cd2(DDCBA)·DMA·H2O]·H2N(Me)2(2) havebeen synthesized under solvothermalcondition by using a less-exploited symmetrical pentacarboxylate ligand,3,5-di(3′, 5′-dicarboxylphenyl)benozoic acid (H5L). Both compounds 1and 2revealthe (5,5)-connected nets based on the binuclear metal clusters andorganic linkers. The desolvated structure of 1(1a) contains two shapes of 1D channel with suitable pore sizeand polar system decorated by uncoordinated carboxylate groups. Asa result, 1apossesses not only high CO2loadingbut also excellent CO2/CH4selectivity at 273and 298 K. In addition, both compounds display solid-state luminescencestemming from the ligand-centered fluorescence of H5L. [ABSTRACT FROM AUTHOR]

Sixnew metal-organic frameworks (MOFs) with structuresranging from a one-dimensional (1D) chain, two-dimensional (2D) layer, even 2D double layer to three-dimensional (3D) network based on 2,2'-bipyridine-3,3'-dicarboxylate-1,1'-dioxide(H2bpdado) and N-donor ligands (1,2-bis(4-pyridyl)ethane(bpa) or 1,2-trans-bis(4-pyridyl)ethene (bpe)),namely, [Cd(bpdado)(H2O)2]n(1), {[Cd2(bpdado)2(bpa)(H2O)2]·DMF·3H2O}n(2), {[Cd2(bpdado)2(bpe)(H2O)2]·8.5H2O}n(3), {[Pb2(bpdado)2(bpa)]·10H2O}n(4), {[Pb2(bpdado)2(bpe)]·10H2O}n(5), [Pb2(bpdado)Cl2(H2O)2]n(6), were synthesized by hydro(solvo)thermal and/or diffusionmethods. In these complexes, the bpdado ligand shows four types of coordination modes, three of which appeared for the first time. Polymers 1-6present diverse motifs with differentmetal ions and different conformations and/or coordination modes ofbpdado, which may show a natural synergy in structural diversity ofthe resultant MOFs. Under the similar synthetic conditions just withdifferent metals (Cd(II) and Pb(II)), 6exhibits a 2Dcovalent grid layer, whereas complex 1displays a 1Dchain. Meanwhile, Cd(II) atom in 1shows an unprecedentedtriangular prism coordination geometry. Although bpe/bpa ligands actas pillars between 2D [M(bpdado)]nlayersubunits in complexes 2-5, the Cd(II)-basedcomplexes 2and 3are extended into a 3Dlayered-pillared network, while the Pd(II)-based complexes 4and 5just exhibit the 2D double layers. Moreover, the 2D [Cd(bpdado)]nlayer subunits of 2and 3can be derived from replacing hydrogenbonds in 1D 1with coordination bonds dependent on differentcoordination modes of bpdado. In addition, the solid-state luminescence(for 1-6) and gas adsorption properties(for 2and 3) have been studied and discussedin detail. [ABSTRACT FROM AUTHOR]

Twoisomeric metal–organic frameworks, consisting of Co-triazolatelayers and positional isomeric dicarboxylate pillars, both show distincttemperature-dependent CO2sorption behaviors. Because ofthe pores functionalized by amino groups, both materials have highCO2uptake and highly selective sorption of CO2over CH4and N2. [ABSTRACT FROM AUTHOR]

Under solvothermalconditions, six new Zn(II) coordination polymers,[(CH3)2NH2]2[Zn(L)]·2H2O (1), [Zn2(L)(py)2] (2), [Zn2(L)(bpe)2]·bpe·6H2O (3), [Zn2(L)(bpe)(DMA)(H2O)]·5H2O (4), [Zn2(L)(bpy)0.5(H2O)2]·2.5H2O (5), and [Zn2(L)(bpe)(H2O)]·3H2O (6) [H4L = 5,5′-(p-xylylenediamino)-1,1′,3,3′-(benzenetetra-carboxylicacid), py = pyridine, bpy = 4,4′-dipyridine and bpe = 1,2-bis(4-pyridyl)ethane],have been synthesized by employing a flexible tetracarboxylic acidH4L and different auxiliary pyridine-based ligands. In 1–6, all L4–ligandsare 4-connected nodes; however, the diverse configurations of thetwo terminal isophthalate units of L4–around thecentral −NHCH2PhCH2NH– spacerlead to various topological nets. 1shows a three-dimensional(3D) 2-fold interpenetrated 4-connected dianetwork resultingfrom the vertical configuration of the two isophthalate units of L4–. 2displays a 3D (4,4)-connected ptsnet in which the two isophthalate units of L4–adopt a parallel configuration. The two isophthalate units of L4–in 3are also almost parallel, resultingin an intriguing 3D 2-fold interpenetrated network with the (4,4)-connected bbfnet. 4is a two-dimensional bilayer structure,extending into a 3D supramolecular framework through interlayer hydrogen-bondinginteractions. 5and 6disclose similar 3Dstructural architectures, in which the two isophthalate units of L4–are almost vertical and exhibit tetrahedral topologicalnodes, inducing a rare (4,5)-connected xwwnet and anunprecedented (4,6)-connected network, respectively. The thermal stabilitiesand luminescent properties of 1–6have also been studied in detail. The complexes exhibit intensesolid-state fluorescent emissions at room temperature. [ABSTRACT FROM AUTHOR]

By reacting a tritopic ligand 5-(4-carboxyphenyl)nicotinicacid(H2cpna) with Co(NO3)2under differentconditions, two new three-dimensional (3D) frameworks, [Co2(cpna)2(H2O)3]·DMF·9(H2O) (1) and [Co4(cpna)4(H2O)8] (2), have been obtained. Theyexhibit (3,6)-connected topological nets based on Co2clustersand Y-shaped trinodal cpna2–linkers. 1presents a chiral anhnet with the right-handed helicalchannels, while 2shows an achiral framework with a rtltopology. The whole structures of 1and 2are constructed from 2D achiral layers interconnected bytriangular cpna2–nodes. Notably, these layers containtwo heterochiral vertical and parallel 21helical chainsfor 1and 2, respectively, and those chainsare constructed with 4-connected tetrahedral or square planar centersin their respective layers. The magnetic studies indicate that 1and 2show antiferromagnetic and weak ferromagneticexchanges transmitted through μ2-Owater/μ1,3-carboxylate bridges and carboxylate singleμ2-O bridges between Co2+ions in theCo2dimers, respectively. In addition, 1displaysmicroporous sorption for N2and CO2. [ABSTRACT FROM AUTHOR]