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The document is a contents list for the journal CrystEngComm, which focuses on the design and understanding of solid-state and crystalline materials. It includes a range of papers on various topics, such as photon upconversion, catalytic activity, structural diversity, and crystal stability. The journal is published by The Royal Society of Chemistry, a leading chemistry community. [Extracted from the article]

In this paper, three isostructural 1D lanthanide complexes, [Ln(dppc)(H2O)4]n·2nH2O (Ln = Eu, Tb and Eu0.501Tb0.499, named 1-Eu, 2-Tb and Eu0.501Tb0.499), based on 3-(2,4-dicarboxylate phenyl)-2-pyridinecarboxylic acid (H3dppc) have been synthesized and characterized by elemental analysis, IR, PXRD, TG and X-ray crystallography. The complexes exhibit a 1D chain structure, which is further linked into a 3D supramolecular framework by hydrogen bonds. Tuneable emission colour of Eu0.501Tb0.499 is realized by adjusting the excitation wavelength. The sensing properties of 1-Eu and 2-Tb towards Fe3+ and aniline indicate that the two complexes have almost the same superior sensitivity and low detection limit for Fe3+ in aqueous solution, while they have different detection abilities for aniline in DMF solvent. The different detection abilities were discussed by means of PXRD, UV-vis, luminescence lifetimes and molecular surface calculations (Hirshfeld surface analysis and 2D fingerprint plots). [ABSTRACT FROM AUTHOR]

A semi-flexible imidazole-based urea ligand, 1-(3-(1H-imidazol-1-yl)propyl)-3-phenylurea, and three zincdicarboxylate coordination polymers possessing the ligand were synthesized and characterized. The stoichiometry and coordination number of the zinc(II) ions in the coordination polymers were found to be dependent on the positional isomers of the benzene dicarboxylate. The 1,3-benzenedicarboxylate-based coordination polymer has a one-dimensional structure, whereas, the one possessing 1,4-benzenedicarboxylate has a two-dimensional architecture. The solvent used in the synthesis of the zinc-1,3-benzenedicarboxylate coordination polymer with the ligand played a decisive role on the solvation and conformation of the ligand. The anhydrous form was obtained from a reaction in methanol in which one of the urea moieties has a puckered geometry and the assembly has layers from one-dimensional bunches of coordination chains. However, the same reaction in ethanol provided a solvate having water and ethanol as the solvents of crystallization and it has the two ligands with a stretched geometry forming a cleft-like geometry to include the ethanol molecules. The two forms were not inter-convertible. The coordination polymer with 1,4-benzenedicarboxylate has a 2-dimensional structure with 2 × 2 grids having self-included urea that held DMF molecules by hydrogen bonds. [ABSTRACT FROM AUTHOR]

The supramolecular organization of organic salts has been widely researched, revealing recurring patterns in crystalline lattices that describe their supramolecular properties. In recent years, our research group has underscored the importance of considering the crystalline structures as a whole, incorporating all the necessary energetic and topological information for a comprehensive understanding of the crystalline system. Given this context, we investigated a series of ammonium mono- and dicarboxylate salts (1–12) to determine whether subtle structural modifications in the anionic organic component lead to relevant energy and topology changes in the crystalline lattice. To achieve this, we selected structures whose carboxylate anion only possesses an alkyl chain and is devoid of other functional groups. The ammonium cation (NH4+) was fixed to determine the effect of variations in the alkyl chains of the selected mono- and dicarboxylates, such as length and degree of unsaturation. Additionally, probable crystallization mechanisms were proposed to elucidate some of the topological and energetic aspects involved in the crystallization of these compounds. Destabilizing interactions were observed in 10 crystalline structures, and the MEP data showed that the most destabilizing interactions occur by the proximity of portions with the same type of charge. Some dimers have unexpectedly low intermolecular interaction energies despite having large contact areas. Based on these data we demonstrate the additivity of intermolecular interactions, that is, the low intermolecular interaction energy in these dimers is the result of the sum of destabilizing energies and stabilizing energies. The cluster energy efficiency data revealed that most crystal lattices display typical characteristics of uncharged organic compounds. The proposed crystallization mechanisms showed a gradual increase in nucleus complexity in the initial stages and the total number of nucleation stages, resulting in five main patterns: monomer → 1D → 3D (1–2), monomer → dimer → 2D → 3D (3), monomer → 1D → 2D → 3D (4–5), monomer → dimer → 3D (6), and monomer → 2D → 3D (7–12). [ABSTRACT FROM AUTHOR]

Metal–organic frameworks (MOFs) capable of post-synthetic metalation (PSMet) have garnered significant interest as supports for catalytic metals. The Mn-based MOF, MnMOF-1 ([Mn3(L2Me)3] where L2Me = bis-(4-carboxyphenyl-3,5-dimethylpyrazolyl)methane), has been an exemplar for studying PSMet. Herein we investigate the synthesis of Mn-based MOFs from related flexible ditopic pyrazole carboxylate links, along with the formation of MOFs with similar tetratopic hinged linkers. We show for the first time that MnMOF-1 is likely a kinetic or metastable phase and a newly identified 2D layered material (MnMOF-2D) is the thermodynamically favoured product for this metal–linker combination. Formation of a MnMOF-1 structure with shorter linkers is thwarted by steric clashes that preclude the formation of the Mn3 cluster. This observation prompted the use of density functional theory (DFT) simulations that showed the target material to be very dense, highly strained and thereby energetically unfavourable, but potentially, a hypothetical MnMOF-1 structure with a longer phenylethynyl spacer would be energetically feasible. Finally, the predominance of 2D MOFs formed with shorter flexible links encouraged us to use tetratopic hinged linkers to form 3D frameworks, which was vindicated by the successful synthesis of two new porous 3D Mn-based MOFs, MnMOF-L4 and MnMOF-L5. These results highlight that reticular synthesis of MOFs formed with flexible, non-linear linkers is challenging. [ABSTRACT FROM AUTHOR]

Reactions of Co(II) salt and N,N′-di(4-pyridyl)sebacoamide (L1), N,N′-bis(4-pyridylmethyl)bicyclo(2,2,2,)oct-7-ene-2,3,5,6-tetracarboxylic diamide (L2) or N,N′-di(4-pyridyl)adipoamide (L3) with angular dicarboxylate ligands afforded coordination polymers (CPs) {[Co(L1)(OBA)(H2O)]·0.5H2O}n [H2OBA = 4,4′-oxybis(benzoic acid)], 1a, {[Co2(L1)(OBA)2]·3DMF}n, 1b, {[Co(L1)0.5(SDA)]·2H2O}n (H2SDA = 4,4′-sulfonyldibenzoic acid), 2a, {[Co2(L1)2(SDA)2(H2O)]·2H2O}n, 2b, {[Co(L1)0.5(MBA)]·H2O}n (H2MBA = diphenylmethane-4,4′-dicarboxylic acid), 3, {[Co(L2)(OBA)]·solvent}n, 4, {[Co(L2)(SDA)(H2O)]·solvent}n, 5, {[Co(L2)(MBA)(H2O)]·2H2O}n, 6, [Co(L2)(HFIPBB)(H2O)]n [H2HFIPBB = 4,4-(hexafluoroisopropylidene)-bis(benzoic acid)], 7, and {[Co(L3)(MBA)]·2H2O}n, 8. CPs 1a, 1b, 2a and 2b exhibit a 2D layer with an (84·122)(8)-22,4L2 topology, a 3-fold interpenetrated 3D net with a (412·63)-pcu topology, a 2D → 3D inclinedly polycatenated framework with a (42·68·8·104)(4)2-2,6L1 topology and a 2-fold interpenetrated 3D framework with a (48·67)-msw topology, respectively, and 3 displays a 2-fold interpenetrated 2D layer with a (42·68·8·104)(4)2-2,6L1 topology. CPs 4–6 are 2D layers, showing (64·8·10)(6)-2,4L3, (36·46·53)-hxl and (4·82)-fes topologies, respectively, whereas CP 7 displays a 3-fold interpenetrated 3D net with a (45·8)-dmp topology and 8 forms a 1D → 2D polycatenation with a (63·82·10)(6)2-2,2,4C5 topology. A structural comparison of 1–8 indicates that the flexibility of the bis-pyridyl-bis-amide plays an important role in the formation of entangled Co(II) CPs auxiliarily supported by the angular dicarboxylate ligand. [ABSTRACT FROM AUTHOR]

Understanding the factors governing the self-assembly of organic ligands with metal ions is essential to engineering target molecular arrangements with the desired properties. Indeed, small modifications of the synthetic conditions lead to the obtention of different complexes, varying from discrete monomers to coordination polymers (CPs). Based on the potential coordinating ability of 2-furoic acid (2-FA), we prepared five Zn(II) and Cd(II) complexes to study the behavior of the furane O atom and the competitiveness of the M–O bond formation in methanol (MeOH). Reactions between M(OAc)2·2H2O (M = Zn(II), Cd(II)), 2-FA, and two p-substituted pyridine ligands (isonicotinamide (Isn) and 4-acetylpyridine (4-Acpy)) in MeOH yielded the two dimers [Zn(μ-2-FA)(2-FA)(Isn)2]2 (1) and [Cd(μ-2-FA)(2-FA)(Isn)2]2 (2), the dimeric paddle-wheel [Zn(μ-2-FA)2(4-Acpy)]2 (3), and the monomer [Cd(2-FA)2(4-Acpy)2(OH2)] (4). Their crystal structures have been studied, observing diverse coordination numbers between five and seven and diverse coordination modes of the carboxylate groups. Interestingly, the recrystallization of 4 in acetonitrile (ACN) resulted in a dissolution–recrystallization structural transformation (DRST), leading to an intricate coordination polymer (CP) with the formula {[Cd(μ-2-FA)(2-FA)(OH2)2]n[Cd(μ-2-FA)(2-FA)(4-Acpy)(OH2)]n} (5) exhibiting coordination of the furane O atom. Within this collection of arrangements, 2-FA displayed a great diversity of coordination modes that were combined and interchanged in the DRST process. Their photophysical properties in solution have been analyzed and their quantum yields calculated. Likewise, further insight into the DRST process was obtained from fluorescence measurements. From these results, a pathway for the structural transformation highlighting the crucial role of solvents has been proposed. [ABSTRACT FROM AUTHOR]

Two new metal-organic frameworks based on 2,2′-bipyridine-4,4′-dicarboxylate and La(III) ions were prepared under solvothermal conditions. [La(bpda)3/2(dmf)2]·dmf·H2O, MSU-10, was isolated as a 2D network structure. By introducing a modulator, 1,10-phenanthroline, the 3D network [La(bpda)3/2(dmf)(H2O)2]·dmf MSU-11 could be isolated with the unusual rod-MOF topology zbj. Both the 2D and 3D networks are stable upon guest removal and the activated phases of MSU-10 and MSU-11 exhibit some phase change when soaked in solvents for 24 h. Network analysis allowed the identification of MSU-11 as isoreticular with MOF-80 built from different linkers and metal ions. [ABSTRACT FROM AUTHOR]

The initial evaluation of MOF entanglements as their main limitation is changing to an opportunity since the related benefits are now known. Based on a linear rigid dicarboxylic acid, biphenyl-4,4′-dicarboxylic acid (H2bpdc), and a flexible dipyridyl piperazine ligand, 1,4-bis(4-pyridylmethyl)piperazine (bpmp), with versatile conformations, four divalent metal–organic frameworks (MOFs), namely {[Cu2(bpmp)2(bpdc)2(H2O)2]·1.25DMF·1.5H2O}n (1), {[Zn2(bpmp)(bpdc)2]·2H2O}n (2), {[Cd(bpmp)(bpdc)(H2O)2]·2DMA}n (3), and [Cd(bpmp)1.5(bpdc)]n (4), with entangled structures from interpenetration and self-penetration to polycatenation are reported. In all the products, both bpmp and bpdc acted as linkers, connecting the metal centres into different entangled frameworks: 3D inclined polycatenane (1), 4-fold interpenetrated 3D MOF with the pcu topology (2), non-interpenetrated square net 2D MOF with sql topology (3), and self-penetrated 3D MOF (4). The solvent-dependent formations of Cd-MOFs 3 and 4 are discussed in detail as 3 isolated from DMA/water is a simple square net product, while 4 obtained from DMF/water shows a self-penetrating 3D framework in which three square circuits are interlocked with each other to form a cyclic [3]catenane unit via threading of the S-shaped bpmp. These cyclic [3]catenanes were further linked by the V-shaped bpmp, giving rise to a 3D infinite aggregate of cyclic [3]catenanes via the self-penetration, which seems to be unique. Consequently, all the products shared a square net (or square circuit) layer, which was further extended and interlocked in different ways depending on the conformations and roles of the flexible ligands together with the ligand–ligand or ligand–solvent interactions. The photoluminescence properties of the products were compared with those of free ligands and discussed. [ABSTRACT FROM AUTHOR]

Hydro(solvo)thermal reactions of N,N′-di(3-methylpyridyl)oxalamide (L1) and N,N′-di(4-methylpyridyl)oxalamide (L2) with angular dicarboxylic acids and Zn(II) and Co(II) metal salts afforded six coordination polymers (CPs), namely, [Zn(L1)0.5(FIPBB)·H2O]n [H2FIPBB = 4,4′-hexafluoroisopropylidenebis(benzoic acid)] (1), [Zn(L2)(OBA)·CH3OH]n [H2OBA = 4,4′-oxybis(benzoic acid)] (2), [Co(L2)0.5(FIPBB)·0.25CH3OH]n (3), [Co(L1)(OBA)·2H2O]n (4), [Co(L1)0.5(FIPBB)]n (5), and [Co2(L1)2(FIPBB)2(H2O)5·4H2O]n (6), which have been structurally characterized by using single-crystal X-ray diffraction. CPs 1 to 6 form a two-dimensional (2D) net with the bey, a polycatenated 2D net with the sql, a three-dimensional (3D) framework with the 6T9, a 2D net with the 3,5L2, 2D net with the bey and a one-dimensional (1D) looped chain with the 2,2,2,4C10 topologies, respectively. The distinct topological switch between 5 and 6 in the presence and absence of coordinated/cocrystallized water molecules was triggered under various temperatures through coordination and breakage of Co–O bonds. CPs 1 and 2 exhibit sustained porosities indicated by CO2 adsorption and exhibit high selectivity toward detection of pesticides such as 2,6-dichloro-4-nitroaniline (2,6-DCNA) and 4-nitroaniline (4-NA) with low detection limits and good recyclability up to five cycles. Integrating 1-octadecene with a long alkyl chain into 1–5 to modify the surface wettability induces hydrophobicity, which was verified by the measurement of water contact angles. [ABSTRACT FROM AUTHOR]

Semi-flexible aromatic polycarboxylic acids are gaining impetus in crystal engineering of functional coordination polymers (CPs). This work opens up the use of two ether-bridged tetracarboxylic acids, 3-(2,5-dicarboxyphenoxy)phthalic acid (H4dpa) and 5-(2,5-dicarboxyphenoxy)isophthalic acid (H4dia), as versatile and still unexplored linkers for the synthesis of new Zn(II) coordination polymers, formulated as [Zn(μ-H2dpa)(bipy)(H2O)]2n·nH2O (1), [Zn2(μ4-dpa)(bipy)2(H2O)]n (2), [Zn2(μ3-dpa)(μ-bpa)2]n·nH2O (3), [Zn2(μ4-dia)(bipy)2]n (4), and [Zn2(μ7-dia)(py)2]n (5). These compounds were prepared via a facile hydrothermal procedure using ZnCl2, H4dpa or H4dia linkers, and supporting N-donor ligands (2,2′-bipyridine, bipy; bis(4-pyridyl)amine, bpa; or pyridine, py) acting as crystallization mediators. Compounds 1–5 were fully characterized and their X-ray crystal structures were established, disclosing the metal–organic architectures that range from 1D chains (1, 2, 4) to 2D layers (3) and 3D framework (5). Both the structural and topological features of 1–5 were underlined, indicating their dependence on the type of linker and/or mediator of crystallization. Thermal, emission, and catalytic properties of 1–5 were also investigated. In particular, the catalytic potential of the obtained CPs in the Knoevenagel condensation of benzaldehydes with propanedinitrile was evaluated, disclosing an excellent performance of several heterogeneous catalysts with up to 99% product yields. All the CPs obtained herein are the first examples of structurally characterized coordination compounds assembled from H4dpa and H4dia. The present study thus opens up the application of these ligands as novel ether-bridged tetracarboxylate linkers in designing functional crystalline materials. [ABSTRACT FROM AUTHOR]

Studies on the recycling of uranium, such as its usage as new materials, can promote the safe treatment of nuclear waste. In this work, with the direction of transition-metal complex cations, three uranyl–organic frameworks (UOFs) with different dimensions have been synthesized via a hydrothermal reaction, i.e. [Cu(phen)2(SO4)(UO2)(TDC)·H2O]n (1), {[Zn(phen)3][(UO2)2(TDC)3(TDC)]·6H2O}n (2), and {[Cd(phen)3][(UO2)2(TDC)2(OX)·2H2O]}n (3), (TDC = thiophene-2,5-dicarboxylic acid, OX = oxalate, and phen = 1,10-phenanthroline). With the presence of SO42−, 1 presents a rare neutral 1-D Cu/U heterometallic chain. Under the similar [Zn(phen)3]2+ and [Cd(phen)3]2+ templates, 2 is a 2-D [(UO2)2(TDC)3]n planar non-interpenetrated honeycomb layer, but 3 presents an interesting twofold interpenetrated (6,3) sheet structure, which is led by the larger cavity of the hexagonal motif with the presence of the second ligand OX. This trend could be helpful for the oriented construction of UOFs. Intra- and inter-layer hydrogen bonds between the honeycomb structure and guest cations and π–π stacking interactions contribute to the stabilization of the overall framework. Complete quenching of uranyl luminescence via nonradiative decay can be observed in 1, and 2 and 3 emit yellow fluorescence with well-resolved vibronic fine structures. The interpenetrated arrangements could give rise to weakened uranyl emission. [ABSTRACT FROM AUTHOR]

To explore the proximity effect in uranyl coordination of weakly-bonded cucurbit[6]uril(CB[6])-bipyridinium ligands, a new pseudorotaxane precursor C7BPCN3@CB[6] containing 1,1′-(heptyl-1,7-diyl)bis(3-cyanopyridin-1-ium) bromide (C7BPCN3) with elongated alkyl chains and meta-substituted cyano groups, has been synthesized and used to react with uranyl cations. Due to the weak binding affinity between the host and guest components of the supramolecular ligand, five new uranyl-rotaxane coordination polymers URCP1–URCP5 have been prepared, in which the pseudorotaxane linkers have shown great conformation diversity and abundant coordination behaviors. Three different coordination modes are present in the as-synthesized uranyl compounds, one of which is host–guest synergetic coordination due to the proximity effect between the meta-coordination carboxylate groups of C7BPCN3 and the portal carbonyls of CB[6]. Specially, the elongated spacer and weak-bonded feature make both CB[6] host and C7BPCN3 at one end of the pseudorotaxane ligand involved in the synergetic chelating with the uranyl centre. Meanwhile, at the other end, only the C7BPCN3 guest can participate in the first coordination sphere of uranium atom. This is the first time that this unique coordination mode has been observed in uranyl coordinating polyrotaxanes. This work demonstrates the proximity effect on uranyl coordination of weakly-bonded CB[6]-bipyridinium pseudorotaxane linkers, and provides an alternative approach to achieve metal coordination regulation and structure diversity in uranyl coordination polymers involving mechanically interlocked molecules. [ABSTRACT FROM AUTHOR]

Some of the uncertainties inherent to solvo-hydrothermal synthetic methods which often hinder isolation of the desired product are discussed and illustrated by the structural characterisation of four uranyl ion complexes with long-chain saturated or unsaturated aliphatic dicarboxylate ligands, this being placed in the context of previous results. [Zn(phen)2(HCOO)][UO2(muc)(HCOO)] (1), where H2muc is trans,trans-muconic (trans,trans-1,6-hexa-2,4-dienedioic) acid, includes formate anions, generated in situ from N,N-dimethylformamide (DMF) hydrolysis, as chelating ligands on both metal centres, which limits polymer periodicity. [UO2(muc)(NMP)] (2) was obtained in the presence of PPh4+ cations, but coordination of N-methyl-2-pyrrolidone (NMP) results in formation of a neutral monoperiodic polymer instead of an anionic one. Similarly, NMP complexation prevents inclusion of [Co(en)3]3+ cations in [UO2(C8)(NMP)] (3), where H2C8 is 1,8-octanedioic acid, another monoperiodic coordination polymer. No solvent is coordinated in [H2NMe2]2[(UO2)2(C13)3] (4), where H2C13 is 1,13-tridecanedioic acid, but the desired [Co(en)3]3+ counterions are displaced by H2NMe22+ cations generated in situ from DMF hydrolysis, giving a diperiodic network with the KIa topological type, isomorphous to that formed from 1,15-pentadecanedioic acid. Complexes 1 and 2 are non-emissive in the solid state, while 4 displays a broad uranyl emission peak with unresolved fine structure. [ABSTRACT FROM AUTHOR]

Spiro[3.3]heptane-2,6-dicarboxylic acid (Fecht's acid, H2SHDC) is examined as a non-aromatic terephthalic acid isostere for the first time. The rigid spirocyclic backbone provides greater steric bulk than conventional aromatic dicarboxylates with consequences for pore chemistry and control of interpenetration, presented here in the structures of two new MOFs. Complex 1 is a three-dimensional rod packed structure consisting of Yb-carboxylate chains bridged by SHDC linkers which, although non-porous, exhibits a surprisingly high thermal stability for a spirocyclic cyclobutane derivative. Complex 2 is a co-ligand complex of SHDC with trans-1,2-bis(4-pyridyl)ethene (bpe) which contains linear solvent channels despite fourfold interpenetration. Although the framework does not retain its structure following evacuation, a clear difference is observed in the extended structure compared to the structurally related terephthalate species. This observation suggests the non-aromatic backbone of Fecht's acid and other rigid aliphatic linkers may prove an effective means to disfavour deleterious close inter-framework contacts which prevail in interpenetrated aromatic MOFs. [ABSTRACT FROM AUTHOR]

To study the effects of metal ions and various carboxylates on the assembly and structures of coordination polymers (CPs) based on a bis-pyridyl-bis-amide ligand [N,N′-bis(4-methylpyridine-4-yl)-2,6-naphthalene dicarboxylamide] (4-bmnpd), eight Zn(II) and Cd(II) CPs, namely [Cd(4-bmnpd)(2-NBA)2] (1), [Cd(4-bmnpd)(3-NIP)(H2O)] (2), [Cd2(4-bmnpd)(TCPA)2] (3), [Cd(4-bmnpd)(5-HIP)(H2O)] (4), [Cd(4-bmnpd)0.5(5-MIP)(H2O)] (5), [Cd3O(4-bmnpd)(1,4-PHDA)2(H2O)]·H2O (6), [Zn(4-bmnpd)(5-MIP)] (7) and [Zn(4-bmnpd)(1,2,4,5-BTA)0.5]·2H2O (8) [2-HNBA = 2-nitrobenzoic acid, 3-H2NIP = 3-nitrophthalic acid, H2TCPA = tetrachlorophthalic acid, 5-H2HIP = 5-hydroxyisophthalic acid, 5-H2MIP = 5-methylisophthalic acid, 1,4-H2PHDA= 1,4-phenylenediacetic acid and 1,2,4,5-H4BTA = 1,2,4,5-benzenetetracarboxylic acid] were synthesized under hydrothermal conditions. CPs 1–8 were characterized by elemental analysis, IR and powder X-ray diffraction. Both CPs 1 and 2 are 2D networks. CP 3 shows a 2D 3,4,5-coordinated net based on binuclear nodes. CPs 4 and 5 are 2D lamellar structures with (4,4) and (3,4) topologically connected patterns, respectively. CP 6 is a 3D framework constructed from multi-member [Cd10(1,4-PHDA)4]n rhombus rings and 1D [Cd3O2]n chains. CP 7 is a 1D ladder structure. CP 8 is a 2D structure extended by deprotonation of 1,2,4,5-H4BTA and 4-bmnpd linkers. The influence of the choice of metal as well as the carboxylic acid on the structures of the above CPs is discussed in detail. The fluorescence sensing properties of CPs 1–8 toward metal cations (Fe3+), anions (CrO42−, Cr2O72−) and antibiotics (oxytetracycline) were investigated. The limits of detection for Fe3+, CrO42−, Cr2O72− and oxytetracycline were 6.9 × 10−5–1.5 × 10−4, 6.9 × 10−5–1.3 × 10−4, 7.7 × 10−5–1.3 × 10−4, and 8.5 × 10−5–9.6 × 10−4, respectively. [ABSTRACT FROM AUTHOR]

Herein, we report the synthesis and crystal structure determination of a new Cu(II) coordination polymer (CP) with the formula [Cu(L -tryp)(azpy)1/2(H2O)(NO3)]∝ (CP1), which exhibits an unusual tryptophan coordination mode with copper(II) via carboxylate monodentate binding as well as chelation via Namino and Ocarbonyl groups. CP1 was prepared using the ligand L -tryptophan (L -tryp) and the co-ligand 4,4′-azopyridine (azpy), adapting the mixed-ligand approach and a solvothermal protocol. Single crystal X-ray structural analysis revealed that in CP1, Cu(II) sites show a distorted octahedral geometry, wherein the ligand L -tryp is coordinated through the carboxylate and amine groups, whereas the co-ligand azpy is coordinated to Cu(II) ions through the Npyridyl atom and thus maintains a distorted octahedral geometry around the Cu(II) ions. FT-IR and EPR spectra were also recorded to corroborate the structural analysis. Finally, CP1 was employed as a heterogeneous catalyst for the Suzuki cross-coupling reaction and afforded ∼98% yield under normal reaction conditions. [ABSTRACT FROM AUTHOR]

A water stable Eu3+-organic framework (1-Eu), [Eu(HL)(H2L)]·7.5H2O (H3L = 3-(3,5-dicarboxylphenyl)-4-carboxylpyridine) was constructed through solvothermal synthesis and studied by structural analyses and luminescence sensing. Crystallographic studies revealed that 1-Eu was a 3D framework in which two adjacent Eu3+ ions with a single isophthalate bridge were interlinked by organic ligands HL or H2L and contained uncoordinated carboxylate groups. 1-Eu represents the (3,3,6,6)-connected (42·10)(42·10)(43·85·105·122)(44·82·104·125) topology. As expected, 1-Eu exhibits a strong red-light emission at room temperature. And 1-Eu also shows good thermal stability and high chemical stability in common solvents and even in acidic or basic solutions (pH = 3 to 12). Therefore, the strong luminescence, good stability and presence of free carboxylate oxygen atoms in the framework allow 1-Eu to serve as an excellent luminescence sensor for probing Fe3+ and Cr2O72− ions in water with quenching constant (KSV) values of 3.38 × 104 M−1 and 2.23 × 104 M−1, respectively. In addition, 1-Eu can be further used as a sensor for amines with high (KSV) values and relatively low limit of detection (LOD), e.g. the KSV and LOD values of ethylenediamine (EN) are 6.25 × 106 M−1 and 0.23 μM, respectively. Meanwhile, the luminescence intensity of the quenched 1-Eu samples will be recovered after washing with water, indicating that 1-Eu can act as a multiresponsive luminescence sensor for Fe3+, Cr2O72− and amines with high selectivity, sensitivity and recyclability. Moreover, the luminescence sensing mechanisms for the above different analytes were proposed. [ABSTRACT FROM AUTHOR]

2,2′:6′,2′′-Terpyridine-4′-carboxylic acid (tpycH) has been used as a ligand in the synthesis of four uranyl ion complexes under solvo-hydrothermal conditions. The homometallic complex [(UO2)2(tpyc)(HCOO)(OH)2] (1) contains additional hydroxide and formate anions generated in situ and it crystallizes as a monoperiodic coordination polymer in which uranyl cations are bound to both the carboxylate group and the terpyridine N3 site. Addition of PbII gives the heterometallic complex [UO2Pb(tpyc)(HCOO)2(OH)(H2O)2] (2), in which uranyl is bound to the carboxylate group while lead(II) occupies the N3 site, further hydroxide- and formate-bridging resulting in a diperiodic arrangement. Both complexes [UO2Ni(tpyc)2(OH)(H2O)]·NO3·1.5H2O (3) and [(UO2)2Ni2(tpyc)4(O)(H2O)4]·(NO3)2·6H2O (4) contain the neutral, octahedral Ni(tpyc)2 "expanded ligand" unit, the uranyl cations being bound to the divergent carboxylate groups and to bridging hydroxo or oxo groups. Complex 3 crystallizes as a heavily corrugated diperiodic assembly in which hydroxo-bridged dinuclear secondary building units are the nodes of a network of sql topology. Chiral, diperiodic polymers with the same topology but a different shape and which are involved in twofold parallel interpenetration, are formed in 4. [ABSTRACT FROM AUTHOR]

The marketed formulation of pazopanib (PAZ) suffers from low and variable bioavailability because of its poor dissolution rate and photostability issues. The drug falls under Biopharmaceutics Classification System (BCS) class II of low solubility and good permeability. The hydrogen bonds and supramolecular interactions in crystalline forms of PAZ with hydroxybenzoic acids (HBAs) and dihydroxybenzoic acids (DHBAs), as well as its salts are analyzed. Ten X-ray crystal structures of PAZ which include the reference drug, a tetrahydrofuran solvate (PAZ·THF) and eight salts with HBAs/DHBAs are reported. There is proton transfer from the carboxylic group of the coformer acid to the most basic nitrogen atom of the 2-aminopyrimidine ring of PAZ in all cases. Two salts were crystallized in neat form, while the remaining six are solvates and hydrates. The crystal structure of PAZ is stabilized by sulfonamide and 2-aminopyrimidine homosynthons of N–H⋯O and N–H⋯N hydrogen bonds in an R 22 (8) ring motif. PAZ·HBA/DHBA salts consistently contain the aminopyridinium⋯carboxylate N+–H⋯O− synthon of the R 22 (8) ring. The sulfonamide homosynthon of PAZ is disrupted in preference to the formation of N–H⋯O and N–H⋯N hydrogen bonds in salt structures. The presence of an additional basic nitrogen atom in the indazole ring of PAZ promotes hydration and solvation through the O–H⋯N hydrogen bond. Whereas the formation of salts is desirable for pharmaceutical formulation, the inclusion of adventitious solvent and/or water molecules with hydroxybenzoic acid coformers in the cocrystal-salt products is a limitation for this class of coformers. The stability problem faced with hydrates and solvates of PAZ·HBA/DHBA salts means that their formation must be carried out by strictly anhydrous procedures. The consistent occurrence of the aminopyridinium⋯carboxylate N+–H⋯O− ring synthon is discussed in relation to the previous results of Aakeröy, Nangia and Zaworotko groups on similar acid–base multi-component systems. [ABSTRACT FROM AUTHOR]

Three new air-stable coordination compounds [Cu(HL)2(H2O)2]2·2H2O (1), [Cu(HL)2]n (1a), and [Zn(HL)2(H2O)2] (2), where HL = N-(4-hydroxyphenyl)oxamate, were successfully synthesized and characterized. Single-crystal X-ray analysis reveals 1 as a dinuclear copper(II) complex, in which the metal ions are connected through the carboxylate moieties of the oxamate ligands. The crystal structure of 1a is solved using powder X-ray diffraction data and stands for an anhydrous mononuclear copper(II) oxamate complex. 2 corresponds to the first example of a mononuclear Zn2+ oxamate complex containing both ligands and water solvent molecules in the cis arrangement. The presence of a phenol group in the oxamate ligand leads to different hydrogen bond patterns in the crystal packing in 1, 1a, and 2, resulting in supramolecular 3D architectures. Magnetic measurements of 1 reveal a ferromagnetic coupling between the copper(II) ions through the carboxylate–oxamate bridge [J = +0.829 cm−1, g = 2.101, zJ = +0.154 cm−1; H = −JSCu1·SCu2, where SCu1 = SCu2 = 1/2]. DFT calculations based on the broken symmetry formalism (DFT-BS) were performed to provide insight into the magnetic behavior. [ABSTRACT FROM AUTHOR]

Two highly stable metal–organic frameworks (MOFs) assembled by a flexible 1,4-bis(2-methylimidazol-1-yl)butane (bib), and two different aromatic carboxylate coligands, namely, [Zn(BDC–OH2)(bib)] (1) and [Cd3(BTC)2(bib)(DMF)3] (2) (H2BDC–OH2 = 2,5-dihydroxyterephthalic acid, H3BTC = 1,3,5-benzenetribenzoic acid), were designed and synthesized. 1 showed a 4-fold interpenetration of 4-connected dia-type topological net. In 2, the 3D topological structure can be viewed as a (3,4,5)-connected network, and its Schläli point is {4·62}2 {42·6·83} {46·89}. Different auxiliary carboxylate ligands were examined with respect to the building of various structures. 1 and 2 have outstanding photocatalytic behaviors for the disintegration of methyl violet (MV) under UV irradiation. [ABSTRACT FROM AUTHOR]

To investigate the effects of metal ions and angles of the carboxyl groups of dicarboxylates on the structures of coordination polymers, four Zn(II)/Cd(II) coordination polymers [Zn(L)(1,4-BDC)]·H2O (1), [Zn(L)(1,3-BDC)]·H2O (2), [Zn(L)(1,2-BDC)] (3) and [Cd(L)0.5(1,2-BDC)(H2O)] (4) [L = N,N′-bis(pyridin-3-ylmethyl)-terephthalamide, 1,4-H2BDC = terephthalic acid, 1,3-H2BDC = isophthalic acid, 1,2-H2BDC = phthalate] were prepared under hydrothermal conditions. Polymers 1 and 2 are 2D structures with 63 and 44 topology. Polymer 3 shows a 4-connected 3D framework, and 4 features a 1D structure with single/double alternate linkers. The effects of the positions of carboxyl groups and the coordination characteristics of metal ions on the structures of the title coordination polymers were studied. The title coordination polymers show multi-functional fluorescence responses towards metal ions (Fe3+), anions (CrO42−, Cr2O72−) and pesticides (2,6-DC-4-NA) and good stability in a wide range of pH values. Taking 1 as an example, the mechanism was also explored by UV-visible absorption spectroscopy and the fluorescence lifetime experiment. [ABSTRACT FROM AUTHOR]

An analysis of the crystal structures of secondary ammonium carboxylate salts using the ring stacking and laddering principle has been carried out. A Cambridge Structural Database analysis showed that this ionic model is applicable to the structures of these salts, and gives additional insight into their structural motifs. The crystal structures of seven new secondary ammonium carboxylate salts are reported, and analysed in terms of ring stacking and laddering. [ABSTRACT FROM AUTHOR]

A carboxylate⋯iodine supramolecular heterosynthon can be reliably applied in cocrystal engineering, using metal carboxylates as building blocks. Analysis of the energy framework of the exemplary paddlewheel crystal [Cu(OAc)2MeOH]2 indicates a robust 1D chain and even 2D layer long-range synthon modules, which can be intactly transferred into cocrystals. However, this approach allows the identification of a "weak link" – i.e. layers where the C–H⋯O＝C hydrogen bonds between ([Cu(OAc)2(MeOH)]2)n polymeric chains will be subject to substitution by I⋯O＝C halogen bonds during interaction with halogen bond donor co-formers. In contrast to the O–H⋯O＝C/C–H⋯O＝C catemeric crystals of pure acetic acid, the crystal design exercise based on the I⋯O＝C(carboxyl) supramolecular synthon afforded a 1 : 1 cocrystal of 1,4-C6F4I2 and CH3COOH, where the discrete centrosymmetric dimers of acetic acid are stabilized by I⋯O＝C(carboxyl) halogen bonds. [ABSTRACT FROM AUTHOR]

Assembled from a reduced Schiff base tricarboxylate ligand H3L, two novel Cd-MOFs with the formulae {[Cd(HL)(bpy)]·1.25H2O·1.5DMF}n (LCU-107) and {[Cd(HL)(bpea)·H2O]·H2O·DMF}n (LCU-108) (where LCU stands for Liaocheng University, H3L = 5-(4-carboxybenzylamino)isophthalic acid, bpy = 4,4′-bipyridine, and bpea = 1,2-di(4-pyridyl)ethane), were obtained. LCU-107 possesses a 3D pcu framework based on dinuclear units. LCU-108 demonstrates an interesting 2D → 2D interdigitating and penetrating structure. The flexible carboxylate ligands can all bend in these complexes due to the rotation of –CH2–NH– groups. Luminescence measurements indicated that these two Cd-MOFs show highly selective and sensitive sensing activities toward acetylacetone (acac) and Cr2O72− through a luminescence enhancement and a quenching effect, respectively. The detection limits toward acac are as low as 0.136 and 0.058 ppm, respectively. To our knowledge, these two Cd-MOFs may represent very rare examples of special turn-on acac sensors, as well as being dual-responsive chemosensors for both acac and Cr2O72−. [ABSTRACT FROM AUTHOR]

The self-assembly reactions of 5-aminodiacetic isophthalic acid (H4adip) ligands and Cu2+ ions at different temperatures to produce two one-dimensional (1D) coordination polymers (CPs), {[Cu(H2adip)(H2O)]·5H2O}n (1) and [Cu2(adip)(H2O)3]n (2) are reported. The structures and chemical compositions of both CPs were characterized by using single-crystal X-ray diffraction and other methods. Structural analyses revealed that CP 1 crystallized in the monoclinic C2/c space group, and two crystallographically independent Cu2+ ions were interconnected by H4adip ligands to give a 1D zigzag chain. However, CP 2 belonged to the triclinic P-1¯ space group, and two types of Cu2+ ions were linked through carboxylate groups to generate dinuclear units, which were bridged by H4adip ligands to give a 1D double chain. Moreover, the adjacent chains in both 1 and 2 could be further stacked to form 3D supramolecular architectures through hydrogen bonds. Interestingly, the block crystal 1 can undergo structural transformation to form the sheet crystal 2 when 1 was heated and kept at 80 °C for 12 h, which represents a rare example of structural transformation resulting from the coordination modes of organic ligands triggered by temperature. Both CPs 1 and 2 exhibited ferromagnetic coupling interactions between Cu2+ ions, and the magnetic results also supported the presence of structural transformation processes. [ABSTRACT FROM AUTHOR]

Two D–A type Zn(II) coordination complexes ([Zn2(L1)2(MeCN)(MeOH)]·(MeCN) (1) and [ZnL2(H2O)] (2)) were synthesized from diaminomaleonitrile-based (DMN) Schiff-base ligands (L1 = 2-amino-3-[(2-hydroxynaphthalen-1-ylmethylene)-amino]-but-2-enedinitrile, L2 = 2-[(4-chloro-2-hydroxybenzylidene)-amino]-3-[(2-hydroxynaphthalen-1-ylmethylene)-amino]-but-2-enedinitrile). Based on the weak blue fluorescence in THF solution and the bright yellow fluorescence in the solid state, the ligand L1 shows obvious aggregation induced emission (AIE) in a THF–H2O solvent system. The fluorescence emission of complexes 1 and 2 exhibits a significant red-shift relative to that of the ligand in THF solution. Interestingly, because of aggregation caused by the interaction between L1 and iodide (I−), complexes 1 and 2 exhibit excellent selectivity for fluorescence detecting iodide, and the quenching efficiency of 2 with iodide is higher than that of 1. [ABSTRACT FROM AUTHOR]

To research the effect of carboxylates on the assembly of Ni(II) coordination polymers, a naphthalene-amide ligand L (N,N′-bis(pyridin-3-ylmethyl)naphthalene-2,6-dicarboxamide) and five dicarboxylates [1,4-H2BDC = 1,4-benzenedicarboxylic acid, 1,4-H2PDC = 1,4-phenyldiacetic acid, 5-H2HIP = 5-hydroxyisophthalic acid, 3,4-H2TDC = 3,4-thiophenedicarboxylic acid, 2,5-H2TDC = 2,5-thiophenedicarboxylic acid] were selected to combine with Ni(II) under hydrothermal conditions. Five coordination polymers [Ni(L)(1,4-BDC)(H2O)2] (1), [Ni(L)(1,4-PDC)(H2O)2] (2), [Ni(L)(5-HIP)(H2O)2] (3), [Ni(L)(3,4-TDC)(H2O)2]·3H2O (4) and [Ni(L)(2,5-TDC)(H2O)]2·3H2O (5) were synthesized and structurally characterized by IR, PXRD and X-ray single-crystal diffraction. The title complexes show various structures: 2D 4-connected sql nets (1 and 2), a 3D cds framework of 3, 1D zigzag chain of 4 and 3D irl framework of 5. The electrochemical behaviors of 1–5 and the solid-state luminescence and fluorescence responses of 5 to Fe3+ and bovine serum albumin (BSA) were studied. Encouraged by functional thiophene components, 4 and 5 were used as catalyst precursors to synthesize carbon nanotubes (CNT-4 and CNT-5) by the chemical vapor deposition (CVD) method and characterized by XPS, SEM, TEM and Raman spectroscopy. The removals of contaminants (rhodamine B and Congo red) by 4 and 5 and their derivatives CNT-4 and CNT-5 in the aqueous phase were also comparatively investigated. [ABSTRACT FROM AUTHOR]

To investigate the effect of metal ions on the assembly of complexes derived from a semirigid tripodal carboxylic acid, 5-(4′-carboxylphenoxy) isophthalic acid (H3L), and two rigid chelating terminal N-donor ligands, dipyrazino[2,3-d:2′3′-f]quinoxaline (dpq) and dipyrido[3,2-a:2′,3′-c]phenazine (dppz), seven 0D → 3D complexes, [Cu(HL)(dpq)(H2O)2] (1), {[Co(HL)(dpq)(H2O)]·H2O}n (2), {[Ni3(L)2(dpq)3(H2O)4]·4H2O}n (3), {[Zn(HL)(dpq)(H2O)]·H2O}n (4), {[Cu2(L)(dppz)]·H2O}n (5), {[Co(HL)(dppz)]·H2O}n (6) and {[Ni3(L)2(dppz)3(H2O)3]}n (7), have been hydrothermally synthesized and structurally characterized by IR, TG and X-ray single-crystal diffraction analyses. Complex 1 is a 0D complex processing an unusual μ1-HL2− anion. Complex 2 features a 1D single chain based on Co(II) ions with a 6-coordinated mode. Complex 3 is the first (2,3,4)-connected 3D dpq-based framework derived from single/bimetallic mixed nodes with {83}2{84·122}{8} topology. Complex 4 is a 1D structure based on Zn(II) ions with a 5-coordinated mode. Complex 5 can be described as a 2D (6,3)-connected structure based on carboxyl-bridged Cu4 cores. Complex 6 is a 1D double chain derived from bimetallic nodes. Complex 7 exhibits a 2D double layer with (2,2,3,3,4)-connected nodes. The structural details of 1–7 were discussed. The solid-state luminescence properties of 1–7 and electrochemical properties of 1–3 have been investigated. The luminescence investigations show that 4 is an effective fluorescence probe for environmentally relevant Fe3+ ions. The electrochemical properties of a carbon paste electrode modified by the complexes 1–3 (1-CPE, 2-CPE and 3-CPE) were studied. 1-CPE has good electrocatalytic activity toward the reduction of nitrite, bromate and hydrogen peroxide in solution. [ABSTRACT FROM AUTHOR]

Two kinds of indium-based MOF materials (In-MOF 1 and In-MOF 2) were synthesized using a solvothermal method using two different pyridine carboxylic acid ligands. Single crystal X-ray diffraction shows that In-MOF 1 is a three-dimensional frame containing four connected [In(CO2)4] units and nine connected [In3(μ3-O)(CO2)6N3] units, while In-MOF 2 is a three-dimensional structure with eight connected [In(CO2)3(CO)N] units. Moreover, the adsorption and separation properties of the MOFs for C2H2, CO2 and CH4 were investigated systematically in order to study the regulation of porosity by the subtle changes in the structure of organic linkers. The results show that both kinds of MOFs have certain gas adsorption and separation capacity, which is mainly determined by the structure, function and adjustable porosity. This work not only reports two MOFs with the potential to separate C2H2/CH4, CO2/CH4 and C2H2/CO2, but also provides valuable guidance for the design and synthesis of porous MOFs with better performance in the future. [ABSTRACT FROM AUTHOR]

Indium–tin carboxylate precursors were successfully synthesized by a direct reaction of indium and tin metals with a molten fatty acid under a nitrogen atmosphere at 260 °C. A linear relationship between the reaction initiation temperature and the number of carbon atoms of the fatty acids ranging from capric acid to stearic acid was observed. There was a 7 °C increase in the reaction initiation temperature for an increase of one carbon atom in the fatty acid. Nearly monodisperse 7–9 nm ITO nanocrystals without agglomeration were synthesized by direct pyrolysis of the as-synthesized precursors without using additional organic solvents. The fatty acid had a minor effect on the decomposition temperature and the mean ITO particle size, but affected the particle size distribution. TOF-SIMS data confirmed that the residue fatty acids on the surface of the indium tin oxide (ITO) nanoparticles served as a built-in surfactant leading to excellent dispersity of the ITO nanocrystals in non-polar solvents. [ABSTRACT FROM AUTHOR]

By incorporating a semi-rigid ether-based unsymmetrical tetracarboxylic acid [H4detc = 2,3,3′,4′-diphenyl ether tetracarboxylic acid] with various ancillary dipyridyl ligands [phen = 1,10-phenanthroline, bipy = 4,4′-bipyridine, bpea = 1,2-bis(4-pyridyl)ethane, and bpee = 1,2-bis(4-pyridyl)ethylene], eight new coordination compounds were hydrothermally synthesized. [Mn(H2detc)(phen)2]·H2O (1) and [Cd(H3detc)2(bipy)2·H2O]·6H2O (2) are two supramolecular networks built from binuclear and mononuclear structures, respectively. [Cd2(detc)(phen)2]·0.5H2O (3) and [Zn(H2detc)(bipy)] (4) are two luminescent 1D loop chain structures with [M2(detc)2] metallacycle units. [Ni2(detc)(bpee)2·5H2O]·1.5H2O (5) exhibits a 2D fishbone-like double-layered network. [Co2(detc)(bpea)2·H2O] (6) features a 3D framework containing a 1D [Co2(μ2-COO)(μ2-Ocarboxylate)] chain. [Cu2(detc)(bpee)·2H2O]·4H2O (7) possesses a two-fold interpenetration 3D framework with a pcu net topology. [Ni2(detc)(bpea)2·3H2O]·3H2O (8) displays a three-fold interpenetration 3D framework with a (3,3,4)-connected new topological net. Magnetic susceptibility measurements indicate antiferromagnetic exchange interactions between the Co(II) ions in 6. The photoluminescence spectra of compounds 2, 3 and 4 show the corresponding emission bands of their ancillary dipyridyl ligands. [ABSTRACT FROM AUTHOR]

Herein, four different coordination networks were isolated and structurally characterized by combining two aminocarboxylate ligands, 4,4′-[biphenyl-4,4′-diylbis(azanediyl)]dibenzoic acid and 5,5′-[biphenyl-4,4′-diylbis(azanediyl)]diisophthalic acid (H2L1 and H4L2, respectively), with different transition metals (Zn(II), Zr(IV) and Cd(II)) under solvothermal conditions. The reaction between H2L1 and Zn(NO3)2·6H2O led to two different coordination networks. In PUMflex1-Zn, which has the formula {[Zn4O(L1)3(DMF)2](DMF)5}n·(DMF)x, the ligand always displays a syn conformation (with respect to the central biphenylene scaffold), whereas in the polymorph PUMflex1.1-Zn, one of the three ligands composing the asymmetric unit adopts an anti conformation. Although the two supramolecular isomers have equivalent stoichiometry and dimensionality, they show different topologies and entanglement types: parallel polycatenation of the 63-hcb and 2-fold interpenetration of the 44-sql layers, respectively. In the case of PUMflex1-Zr, with the formula {[Zr6O4(OH)8(L1)4(H2O)2]n·(DMF)x, H2L1 exclusively adopts the syn conformation, forming 1D-chains of rugby-ball shaped aggregates (topological type 2,8C1) interconnected through H-bonds with water molecules. In contrast, H4L2 behaves as a dianionic ligand in PUMflex2-Cd, with the formula [Cd(κ2-COO)2(DMF)3(DMF)]n, forming 1D zig-zag chains connected through the N–H⋯O＝C(OH) H-bonds to provide planar layers of sql topology. In all cases, the ability of the amine functions to interact with the H-bond active guests is structurally highlighted by the recurrent N–H⋯ODMF interaction modelled in the X-ray structures. [ABSTRACT FROM AUTHOR]

The dye molecule 1,2,4,5-tetra(4-pyridyl)benzene (bztpy), a tetradentate ligand, can be an excellent candidate for construction of coordination polymers with photoluminescence properties. Here, based on Ag(I) and bztpy, three novel complexes, namely [Ag2(bza)2(μ4-bztpy)] (1), [Ag2(μ-ipa)(μ4-bztpy)]·EtOH·3H2O (2) and [Ag3(pda)(μ-pda)1/2(μ4-bztpy)2]·3EtOH·6H2O (3) (Hbza = benzoic acid, H2ipa = isophthalic acid and H2pda = 2,4-pyridinedicarboxylic acid), have been synthesized with the assistance of auxiliary carboxylates. The choice of carboxylates was found to have a pronounced effect on the framework topology. Structural analysis revealed that there are [Ag2(bztpy)]∞ chains as basic side groups and the change of interconnected auxiliary ligands from Hbza to H2pda leads to the formation of 1D, 2D and 3D structures, respectively. They were further characterized by elemental analysis, IR, single-crystal X-ray diffraction and luminescence study. [ABSTRACT FROM AUTHOR]

To study the effects of carboxylates on the assembly and structures of Ni(II) coordination polymers (CPs) based on a phenyl/methylene-mixed-bridged bis-pyridyl-bis-amide [N,N′-bis(4-methylenepyridin-4-yl)-1,4-benzenedicarboxamide] (L) ligand, ten 1D → 3D Ni(II) CPs, namely [Ni(L)(2-NB)2(H2O)2] (1), [Ni(L)(4-NB)2(H2O)2] (2), [Ni(L)2(2-MOB)2] (3), [Ni(L)2(3-CB)2] (4), [Ni(L)(2-CP)(H2O)] (5), [Ni(L)(5-NIP)(H2O)2]·2H2O (6), [Ni(L)(3-NP)(H2O)2] (7), [Ni(L)(4,4′-OBA)]·H2O (8), [Ni(L)(1,4-BDC)(H2O)2]·2H2O (9) and [Ni(L)(1,4-CHDA)(H2O)2]·4H2O (10) [2-nitrobenzoic acid (2-HNB), 4-nitrobenzoic acid (4-HNB), 2-methoxybenzoic acid (2-HMOB), 3-chlorobenzoic acid (3-HCB), 2-carboxyphenylacetic acid (2-H2CP), 5-nitroisophthalic acid (5-H2NIP), 3-nitrophthalic acid (3-H2NP), 4,4′-oxybis(benzoic acid) (4,4′-H2OBA), 1,4-benzenedicarboxylic acid (1,4-H2BDC) and trans-1,4-cyclohexanedicarboxylic acid (1,4-H2CHDA)], have been hydrothermally synthesized with various carboxylates and structurally characterized by IR, PXRD and X-ray single-crystal diffraction. 1 and 2 are similar 1D coordination polymers. 3 and 4 feature similar 2D coplanar 4,4-connected networks extended by single L linkers. 5 displays a 2D wave-like 4,4-connected network based on L and 2-CP mixed linkers. 6 shows a 2D 4,4-connected structure derived from L and 5-NIP mixed spacers. 7 is a CdSO4 type 4-connected 3D framework. 8 displays a 2D → 3D parallel polycatenation array based on 2D (4,4)-connected wave-like coordinated layers. 9 and 10 feature similar 2D → 3D inclined polycatenation arrays based on 2D (4,4)-connected coplanar networks. The effects of the carboxylates on the structures of the title complexes are discussed in detail. The solid-state luminescent and fluorescent sensing properties of 1–10 for Fe3+ ions were investigated. Moreover, the effects of 1, 5 and 7 on the fluorescence properties of bovine serum albumin (BSA) and the electrocatalytic activities of carbon paste electrodes (CPEs) bulk-modified with 1, 3, 5, 7 and 9 for the reduction of hydrogen peroxide, bromate and nitrite were studied. [ABSTRACT FROM AUTHOR]

We present a series of six novel Zn(ii) complexes containing anions of perfluorinated biphenyl-4,4′-dicarboxylate (oFBPDC2−). Among them are the 0D complex [Zn(eg)3](oFBPDC) (eg = ethylene glycol), the 1D [Zn(H2O)(ur)(oFBPDC)] (ur = urotropine) and [Zn(CH3OH)2(CH3OCH2CH2OH)(oFBPDC)] and the 2D layered [Zn2(CH3CN)2(oFBPDC)2]·2C6H6·2CH3CN, [Zn2(H2O)2(oFBPDC)2]·4(CH3)2CO, [{Zn4(μ3-OCH3)4}(CH3OH)4(oFBPDC)2]·[{Zn4(μ3-OCH3)4}(H2O)(CH3OH)3(oFBPDC)2]·13CH3OH. The latter coordination polymer is built up by unique Zn4(OCH3)4 cuboidal units. The complexes are characterized by single-crystal X-ray diffraction, FT-IR, elemental analysis, and TGA. Investigation of the CO2 adsorption at 195 K on [Zn2(CH3CN)2(oFBPDC)2] and [Zn2(H2O)2(oFBPDC)2] of the layered polymeric structure revealed that they have BET surface areas of 334.8 and 150.6 m2 g−1, respectively. [ABSTRACT FROM AUTHOR]

To design an effective fluorescence probe for sensing nitroaromatic compounds (NACs) and metal ions, a novel two-dimensional (2D) coordination polymer, {Zn2(NO3)2(4,4′-bpy)2(TBA)} (1) {H2TBA = 4-(1H-tetrazol-5-yl)-benzoic acid, 4,4′-bpy = 4,4′-bipyridine} was synthesized via a hydrothermal method. As expected, 1 presented varying degrees of fluorescence intensity changes for detecting and recognizing trace NACs with high selectivity and sensitivity in water solution. Moreover, 1 not only exhibited a highly selective fluorescence quenching effect on Fe3+ ions in aqueous solution, but could also resist the interference of various other metal ions. In addition, it has been found that the fluorescence quenching mechanisms among NACs and Fe3+ ions are mainly related to the interactions between the host group and guest molecules by energy and electron transfer. [ABSTRACT FROM AUTHOR]

Four new manganese(ii) metal–organic frameworks based on H4bpta (H4bpta = 3,3′,5,5′-biphenyltetracarboxylic acid) and N-donor ligands, namely [Mn2(4,4′-bipy)(bpta)]n (1), [Mn2(1,4-bib)2(bpta)]n·2n(H2O·DMF) (2), [Mn2(1,3-bimb)2(bpta)]n·2nH2O (3), and [Mn2(1,4-bimb)2(bpta)]n·2nH2O (4) (4,4′-bipy = 4,4′-bipyridine, 1,4-bib = 1,4-bis(imidazol-1-yl)benzene, 1,3-bimb = 1,3-bis((1H-imidazol-1-yl)methyl)benzene, and 1,4-bimb = 1,4-bis((1H-imidazol-1-yl)methyl)benzene), have been obtained under solvothermal conditions. In these complexes, the fully deprotonated bpta4− ligands link binuclear SBUs to construct 2D layers with (4,4)-connected topologies. Complex 1 is a 3D network with 1D zigzag chains built up from 4-connected bpta4− ligands that contain carboxylate groups bridging Mn2+ ions in a rather rare syn–syn geometry. Complex 2 exhibits a 3D porous network with syn–anti bridging dimeric subunits. Complex 3 is a (3,4)-connected 2D novel network with double helix chains formed by cis-1,3-bimb linkers. The structure of complex 4 is similar to that of 2, but it consists of tiny pores due to trans-1,4-bimb linkers. Magnetic studies reveal that 1 is perfectly fitted by the modified Fisher model to yield an effective intrachain antiferromagnetic coupling (J = −2.21(1) cm−1). Complexes 2–4 show antiferromagnetic interactions (J = −1.57(2) cm−1 for 2, and J = −0.68(2) cm−1 for 3) in dimeric units of Mn2(μ-COO)22+ related to double syn–anti and syn–syn carboxylate bridges. An important repetitive feature of all these complexes with syn–anti or syn–syn carboxylate bridges is that the antiferromagnetic coupling is very small. In addition, the gas sorption exploration of 2 exhibits relatively high sorption of CO2 but very low sorption of N2, making it a promising material for CO2/N2 separation. [ABSTRACT FROM AUTHOR]

The combination, under mild conditions, of the methylenecarboxylic-appended tetramercaptotetrathiacalix[4]arene (TMTCA) derivative 4, blocked in the 1,3-alternate conformation, with acetate salts of octahedral copper(ii), manganese(ii), nickel(ii) and zinc(ii) leads to the formation, in the crystalline state, of high dimensional coordination networks. Depending on the nature of the used metal cations and bases (pyridine or non-coordinating Et3N), six new different high-dimensional coordination polymers have been evidenced, presenting 4 different coordination patterns. All the compounds present a metal/4 ratio equal to 2/1. The formation of a 2D grid-like compound (4-Zn2(Py)4) and three different pseudodiamondoid-like 3D compounds (4-Co2(Py)6(H2O)2, 4-Ni2(Py)6(H2O)2, 4-Mn2(Py)4(MeOH)2, 4-Mn2(DMF)2(MeOH)4 and 4-Zn2(MeOH)4) is observed. [ABSTRACT FROM AUTHOR]

A series of Ca-based coordination polymers were prepared mechanochemically by milling Ca(OH)2 with phthalic acid (H2oBDC), isophthalic acid (H2mBDC), and terephthalic acid (H2pBDC). The hydrated compounds [Ca(oBDC)(H2O)] (1), [Ca(mBDC)(H2O)3.4] (2), and [Ca(pBDC)(H2O)3] (3) were prepared for the first time via mechanochemical routes. The refined structures were validated by extended X-ray absorption data. The new dehydrated compound [Ca(oBDC)] (1-H2O), obtained after the thermal post-treatment of 1 in a reversible phase transition process, was determined ab initio based on the powder X-ray diffraction (PXRD) data. The materials were thoroughly characterized using elemental analysis, thermal analysis, and spectroscopic methods: magic-angle spinning NMR and attenuated total reflection-infrared spectroscopy. The specific surface areas and sorption properties of the hydrated and dehydrated samples were determined using the isotherms of gas sorption and dynamic vapor sorption measurements. [ABSTRACT FROM AUTHOR]

A systematic investigation on the assembly of a flexible zwitterionic ligand, 1,3-bis(2-carboxyethyl)benzimidazolium (HL), with various Cu(ii) salts under different conditions afforded nine coordination compounds: [Cu2L2(NO3)2]·CH3CN (1), [Cu2L2(H2O)2](NO3)2·5H2O (2), {[CuL(H2O)](NO3)}n (3), [Cu4L4(OH)2(H2O)2](NO3)2·10H2O (4), [Cu2L2(H2O)2](ClO4)2 (5), [CuL(H2O)3]2SO4·7H2O (6), [Cu(HL)2Cl2] (7), [Cu2L2Cl2]·2H2O (8) and {[Cu2L2Cl2]·2H2O}n (9). Compounds 1 and 8 are neutral paddle-wheel shaped dinuclear clusters with either nitrate or chloride as the axial ligand, while 2 and 5 are composed of identical [Cu2L2(H2O)2]2+ cationic units displaying a paddle-wheel motif with an axially coordinated aqua ligand but different counter anions. Compound 3 exhibits a 1D linear structure, where two adjacent Cu(ii) centers are triply bridged via two carboxylate groups plus one aqua ligand. Compound 4 is a tetranuclear cluster supported by two μ3-bridged OH− groups and four carboxylate bridges. Compounds 6 and 9 are mononuclear species constructed from the dicarboxylate ligand in two different coordination modes. Compound 9 assumes a 1D looped chain topology with paddle-wheel cluster nodes propagated by pairs of flexible linkers. A close examination revealed that the conformational freedom of the flexible dicarboxylate ligand as well as the labile binding modes of its two side arm carboxylates is sensitive to the reaction conditions, thus resulted in the different structural types of these coordination compounds. The solvent-induced reversible single crystal-to-single crystal (SCSC) transformation between 1 and 3 could be easily achieved via the shuttle movement of NO3− outward and inward of the Cu(ii) coordination sphere accompanied by a visible color change. Upon dissolution–recrystallization, the irreversible or reversible structural transformations among 2, 3, 4 and 6 could be driven by subtly controlling some factors such as solvent, pH, temperature and counter anion. The magnetic measurements for compounds 2–4 demonstrated that their magnetic behaviors are governed by antiferromagnetic interactions despite the fact that dissimilar exchange coupling pathways between neighboring Cu(ii) ions are available in these three compounds. [ABSTRACT FROM AUTHOR]

The dicarboxylate anions of tartrate (C4H4O62−, Tar2−), malate (C4H4O52−, Mal2−), and succinate (C4H4O42−, Suc2−) were originally used as morphology/structure modifiers in the hydrothermal crystallization of YPO4, and both hexagonal (h-) and tetragonal (t-) structured crystals with multiform morphologies of high uniformity were selectively synthesized. The materials were characterized by the combined techniques of XRD, FE-SEM, TEM, FT-IR, TG, and optical spectroscopy, and the mechanisms of phase/morphology evolution were expatiated. It was clearly shown that Tar2− may induce an inverse phase transformation of YPO4 from the thermodynamically stable tetragonal structure (nanoparticles) to the metastable hexagonal structure (microprisms), and a series of controlled experiments exhibited that the performance of Tar2− was strongly affected by the experimental parameters of Tar2−/PO43−/Y3+ molar ratio, solution pH, hydrothermal temperature, and reaction time. In comparison with Tar2−, Mal2− induced the direct crystallization of h-YPO4 microprismatic crystals while Suc2− restricted the 1-D growth of t-YPO4 nanocrystals. For the samples calcined at 700 °C, the down-conversion photoluminescence of Eu3+ in h-YPO4 and t-YPO4 and the up-conversion luminescence of the (Yb/Er)3+ couple in t-YPO4 were also comparatively studied and elucidated in detail. [ABSTRACT FROM AUTHOR]

Design and synthesis of robust porous lanthanide-based metal–organic frameworks (Ln-MOFs) from flexible organic ligands is currently a formidable task to chemists. In this work, a porous Ln-MOF based on a flexible cyclotriphosphazene-functionalized organic ligand, hexakis(4-carboxylatephenoxy) cyclotriphosphazene, has been solvothermally synthesized. Single-crystal X-ray diffraction analyses show that the compound exhibits a three-dimensional structure built from rod-shaped secondary building units which are linked to each other through the organic ligands to form open frameworks with rectangular channels along the crystallographic a direction. Remarkably, although the flexible ligand was used, the Ln-MOF material after desolvation exhibited permanent porosity which has been established by various gas adsorption isotherms, displaying selective adsorption of C2 hydrocarbons over CH4 at room temperature. This work presents a rare example of a permanently porous Ln-MOF based on a flexible ligand exhibiting selective gas adsorption behaviours. [ABSTRACT FROM AUTHOR]