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A schematic diagram illustrating the structural conversions from nonporous 3D coordination polymer 1 (top) to 3D coordination polymer 2 (middle) and porous 3D coordination polymer 3 (bottom) by solid state reversible anion-replacement.
Source publication
Reversible anion-exchange of nonporous 3D lead(II) coordination polymers with ligand 2,5-bis(4-pyridyl)-3,4-diaza-2,4-hexadiene (4-bpdh), from [Pb(4-bpdh)(μ-NCS)2]n (1) to intermediate 3D [Pb(4-bpdh)(μ-NCS)(NO3)]n (2) and then porous 3D coordination polymers of [Pb(4-bpdh)(NO3)2(H2O)]n (3) and [Pb(4-bpdh)(NO3)2]n (4) by solid state anion-replacemen...
Contexts in source publication
Context 1
... one or two mmol NH 4 SCN for converting of compounds 3, 4 to 2 and 1, respectively. Determination of the structures of compounds 1-4 by X-ray crystallo- graphy (Table 1 and grinding with 1 and 2 mmol of solid NaNO 3 for 20 minutes in an agate mortar lead to formation of compounds 2 and 3, respectively. These processes occur without a color change (Fig. 1). Compound 3 crystallizes in the monoclinic P2/c space group, while the compounds 2 and 1 crystallize in the triclinic P% 1 and monoclinic P2 1 /c space groups, respectively. Compound 4 crystallizes in the monoclinic C2/c space group. Results found for the compounds 1, 2 and 3, 4 provide us with one of the few examples of ...
Context 2
... were washed after mechanochemical reactions and before analysis, so the samples are free from any NaN 3 or NH 4 SCN or other inorganic salts. The structural conversions from 3D coordination polymer 1 (top) to 3D coordination polymer 2 (middle) and 3D coordination polymers 3, 4 (bottom) by solid state reversible anion-replacement are shown in Fig. 1 and 2. On the other hand, these process could be reversible by using one and two mmol NH 4 SCN for converting of compounds 3 and 4 to 2 and 1, respectively. In all four coordination (5) Å a = 7.8060(4) Å b = 14.1233(3) Å b = 12.1582(6) Å c = 20.3576(6) Å c = 20.5067(10) Å a = 90.001 a = 90.072(4)1 b = 109.200(2)1 b = 91.404(4)1 g = 90.001 g ...
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Citations
... The synthetic route to complexes 1-2 is shown in Scheme 7. [PbL 2 (NO 3 ) 2 ] n (3) has been prepared in a similar method using Pb(NO 3 ) 2 and L 2 [95]. (12) have been prepared in similar methods using appropriate lead(II) salts and appropriate ligands (L 3 for complexes 4-7, L 4 for complexes 8-12) [96][97][98][99][100][101]. The synthetic route to complexes 4-12 is shown in Scheme 9. [PbL 1 (2,2-bipy)(H 2 O)(NO 2 ) 2 ] n (19) has been prepared in a solvothermal method in a Teflon-coated stainless steel bomb by heating a mixture of L 1 , 2,2′-bipyridine, Pb(NO 3 ) 2 and methanol at 90 • C for 72 h [104]. ...
... Single crystal to single crystal transformation involving anion-replacement is a challenging area of research now-a-days to develop further understanding of the supramolecular architecture in their solid state structures [149][150][151][152][153][154][155][156][157][158][159][160]. The reversible solid state structural transformations of [PbL 4 (NCS) 2 ]n (12) to [PbL 4 (NCS)(NO 3 )]n (17) by anion-replacement have been established by PXRD and IR spectroscopy [101]. ...
... [100][101][102][103]. The synthetic route to complexes 13-14 and 17-18 is shown in Scheme 10.The synthetic route of complex 15 is shown in Scheme 10A. ...
Coordination polymers (CPs) are a scientifically compelling and evolving class of highly crystalline materials. Owing to their controllable structures and morphologies, CPs can be used as a type of uniformly...
Metal-organic frameworks (MOFs) have recently emerged as a type of uniformly and periodically atom-distributed precursor and efficient self-sacrificial template to fabricate hierarchical porous-carbon-related nanostructured functional materials. In this work, we used Cu(II) ions and aromatic dicarboxylic acid to construct [Cu3(4,4'-oba)2(μ2-OH)2(H2O)2]n (4,4'-H2oba = 4,4'-oxybisbenzoic acid) as a precursor for the preparation of carbon nanostructures. Doping foreign elements into intrinsic MOF-based nanomaterials is an effective way to enhance the adsorption property and photocatalytic activity; thus, we designed a facile method to synthesize a vanadium-doped mixture of Cu2O and Cu nanoparticles encapsulated in a Cu-MOF-derived carbon nanostructure (C-V-1) in this work for the first time. Benefiting from the protection of the carbon shell and regulation of the electronic structure by doping vanadium and phase-mixing Cu2O and Cu, the adsorption capacities of C-V-1 for MB, RhB, MO, CR and GV at room temperature are 174.13, 147.06, 179.92, 275.90 and 611.81 mg g-1 in 240 min, respectively, while the photocatalytic degradation rates are 88.14% for MB, 79.80% for RhB, 71.31% for MO, and 71.19% for CR after 4 h. In addition, the degradation rate is larger than 99.01% for GV after only 30 min of UV irradiation. This strategy of using a diverse MOF as a structural and compositional material to create a multifunctional composite/hybrid may expand the opportunities to explore highly efficient, fast and robust adsorbents and photocatalysts for water treatment.
New 2D lead(II) coordination polymers, Pb(4-bpdh)(CH3COO)(NO3)]n (1) and [Pb(4-bpdh)(ClO4)(NO3)]n (2), 4-bpdh = 2,5-bis(4-pyridyl)-3,4-diaza-2,4-hexadiene, were prepared and characterized by single-crystal X-ray diffraction. Compound 3 with formula [Pb(4-bpdh)(NO3)2(H2O)]n (3) was obtained by solid state mechanochemical reaction of the compounds 1 and 2 via anion-exchange process. These conversions are reversible and the grinding of compound 3 with CH3COO‾ and ClO4‾ ions led to the formation of the compounds 1 and 2, respectively. Thermal decomposition of the compounds 1–3 results in the formation of different metallic composites. The composites were characterized by X-ray powder diffraction (XRD) and size and morphology of them were investigated by scanning electron microscopy (SEM).
An imide-based O-donor ligand, 4-carboxyphenyl-1,3-dioxoisoindoline-5-carboxylic acid (H2In-4-ba), and one Zn(II) coordination polymer, [Zn(In-4-ba)(py)2]n (1, py = pyridine), have been synthesized. Single-crystal X-ray diffraction indicates that 1 has a quasi-31 helical chain structure, which shows one-dimensional to one-dimensional (1D → 2D) extension to be a homochiral layer of consecutively interweaving poly-helices with the same helicity. Coexistence of such homochiral layers in opposite chirality makes individual crystal of 1 to be in a racemic manner. Thermogravimetric (TG) analysis indicated that 1 shows high thermal stability approaching 440 °C. Thermal activation of 1 gives a desolvated phase, [Zn(In-4-ba)]n (1′), as supported by TG trace. Of particular note, reversible crystal-to-crystal transformations between solvated 1 and desolvated 1′ have been achieved upon decoordination and recoordination of the py ligands, as evidenced by XRPD patterns, IR spectra, and TG diagrams. The photoluminescence properties of as-synthesized 1, desolvated 1′, and resolvated 1′/py have also been studied. All of them exhibit an emission band centered at 486, 492, and 486 nm, respectively, which is originated from the ligand-centered charge transfer. Further, the emission intensity of 1′ is weaker than that of 1 and 1′/py, implying the influence of coordinated py ligands and/or structure regulation on photoluminescence.
An aqua-coordinated lamellar net [Zn(5-NH2-1,3-bdc)(H2O)] (1, 5-NH2-1,3-H2bdc = 5-amino-1,3-benzenedicarboxylic acid) has been found to undergo a reversible stimuli-responsive 2D-to-2D crystal-to-crystal transformation with a water-free bilayered-lamellar net [Zn(5-NH2-1,3-bdc)] (1') upon removal and rebinding of aqua ligands, whereas a 2D porous pillared-bilayer [Zn2(5-NH2-1,3-bdc)2(NI-bpy-44)]·DMF (2, NI-bpy-44 = N-(pyridin-4-yl)-4-(pyridin-4-yl)-1,8-naphthalimide) has been tailored by introducing NI-bpy-44 to replace the coordinated aqua ligands. Pillared-bilayer 2 displayed a moderate CO2 uptake of 79.1 cm3 g-1 STP at P/P0 = 1 and 195 K with an isosteric heat of CO2 adsorption (Qst) of 37.0 kJ mol-1 at zero-loading. It is noteworthy that the water suspensions of 1 and 2 both displayed good fluorescence performances, which were effectively quenched by Fe3+, MnO4-, and Cr2O72- ions and shifted to long wavelengths by Fe3+, Al3+, and Cr3+, even with the coexistence of equal amounts of most other interfering ions. Taking the Stern-Volmer quenching constant, limit of detection, quenching efficiency, anti-interference ability, and visual observation into consideration, it is clear that both 1 and 2 are promising and excellent fluorescent sensors for highly sensitive detection of Fe3+, MnO4-, and Cr2O72-.
Heteroaromatic carboxylate ligands are very intriguing components of coordination assemblies such as coordination polymers (CPs) due to their inherently multitopic structures. While the fundamental scheme of bonding in CPs is sustained by carboxylic groups, the heteroatom present in ligand can serve as site for competitive coordination or can play sometimes nonobvious role through range of non-covalent forces such as hydrogen bonding or heteroaromatic π-π stacking. In order to explore coordination abilities of O-containing heterocyclic ligands, we have assembled five CPs from heteroaromatic rigid 2,5-furandicarboxylic acid (2,5-H2FDA) linker and lanthanide nodes (Pr, Eu, Ce and Nd) via hydrothermal synthesis: {[Pr2(2,5-FDA)2(H2O)10]n2+•n[(2,5-FDA)2−6(H2O)]} (1), {[Ln2(2,5-FDA)3(H2O)3(DMF)]n•n[(DMF) xH2O]} [ where Ln = Pr (2), Eu (3); Ce (4), x= 2.33 for CPs 2 and 4 and 2.25 for CP 3] and {[Nd2(2,5-FDA)3(H2O)4]n•n[(DMF)1.5H2O]} (5) (2,5-FDA2-= 2,5-furandicarboxylate, DMF= N,N′-dimethylformamide). From the structural view point, CP 1 is a 1D cationic [Pr2(2,5-FDA)2(H2O)10]n2+ coordination polymer having a guest FDA2−counterion stacked in-between coordination chains and six water molecules occupying lattice sites. The 2,5-FDA2- linker exhibits three different coordination modes viz. (μ2-κO,O:κO,O) in CP 1, and unprecedented for this ligand (μ3-κO,O:κO;κO,O) and (μ4-κO:κO:κO:κO) coordination modes in CP 2-5. The metal organic frameworks 2-5 are isostructural. A dinuclear [Pr2O18] in CP 1 and tetranuclear [M4O32] [M = Pr (2), Eu (3), Ce (4) and Nd (5)] in CPs 2-5 form secondary building units respectively. Topological analysis reveals that the cationic CP 1 shows 2D-(4,4) rhombohedral grid topology by virtue of H-bonding, whereas CPs 2-5 have bcu topology. The structures adopted by the CPs 1-5 are further explored by Hirshfeld Surface (HS) analysis. In particular, specific properties of heteroaromatic π-π stacking and of hydrogen bonding are evaluated using shape-index and dnorm-mapped HSs, respectively. DFT calculations were employed to identify and quantify contributions to the binding energy of stacked 2,5-FDA2- species in CP 1. It was found that π–π interaction of 2,5-FDA2- moieties has modest contribution to the formation of the assembly (–2.6 kcal/mol), which is dominated by stabilization energy of H-bonds and the electrostatic attraction between counter-ions (–44.1 kcal/mol per hydrogen bond). Finally, a strong ligand-sensitized Eu3+f-f luminescence is exhibited by CP 3.
Design and synthesis functional materials with desired properties is the ultimate goal for chemical pursuers. Single-crystal to single-crystal (SCSC) transformation is an important component of solid-state reaction. It can not only form new materials but also provide an opportunity to explore the process of forming a chemical bond which is conducive to bring function-oriented crystal synthesis into reality. In this review, we have provided a broad overview of solid state SCSC transformations taking place in polymers or metal–organic frameworks, and classified them into several parts by various inducing stimuli, such as UV light, heat (temperature change), mechanical force and their synergic impact. Different from the other reviews, solid state SCSC transformations discussed in this paper are confined to transformations via an absolutely solvent-free mode and both the reactant and product are in solid phase. These dynamic processes all involve the breakage and formation of covalent or non-covalent bonds, accompanied by the drastic structural rearrangement in crystalline phase. Changes in physical properties of these complex resulting from solid state SCSC transformations will also be illustrated. Thanks to the regular characteristic of the crystal structure before and after reactions, the transformation process may provide deep insights into rational design of crystalline materials.
Four coordination networks (CNs), i.e., [Co(edb)(H2O)(Py)2], 3; [Cd(edb)(DMSO)2]·0.5(DMSO), 4; [Er2(edb)3(DMSO)2(H2O)2], 5; and [Gd2(edb)3(H2O)4], 6 (edb2- = 4,4’-ethynylenedibenzoate), were synthesized and structurally characterized, and the luminescent properties of CNs 4 and 5 were investigated. In CN 3, the ligand adopts a bridging coordination mode that connects one Co(II) ion to another, resulting in a 1D CN. CNs 4 and 5 contain binuclear centers that are linked to four ligands in the chelating and bridging coordination modes. CN 4 has a 2D → 3D inclined polycatenated structure, whereas CN 5 exhibits a 3D network because the voids created by the long ligand are stabilized by the π-π stacking interactions, thereby avoiding the entanglement of the structure. CN 6 has a paddle-wheel structure with a two-fold interpenetrated rob topology. The photophysical properties of the compound H2edb and CNs 4 and 5 were studied in the solid state. Compound 2 (H2edb) displays strong absorption bands at 325 and 350 nm and emission at 385 nm. Upon complexation with Er(III), the emission was quenched. The emissions of CN 4 were due to the intraligand transitions.
To investigate the influence of the different halides on coordination parameters and exploitable properties, a series of isostructural lead(II) coordination polymers, namely, [Pb(µ-L)(µ-X)2]n (X=Cl (1), Br (2), I (3)) based on rigid ligand N,N'-bis(4-pyridylmethylidyne) phenylene-1,4-diamine (L) were synthesized successfully. The structures of these compounds were elucidated by FT-IR spectroscopy, and single crystal X-ray diffraction crystallography. Single crystal X-ray analyses revealed that these compounds have a 2D net structure containing PbX4N2 centers in which lead(II) ions bridged by both halide anions and L ligands in trans arrangement. Moreover, natural bond orbital (NBO) calculations were employed to obtain atomic charge distributions, hybridizations and the strength of interactions between lead ion and halides via second-order perturbation energies. All materials display a blue luminescence in the solid state at room temperature. Also, there is obvious relationship between the NBO findings and observed red shift order in these compounds. Finally the results of thermal behavior studies of compounds 1–3 have been discussed.
