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The reactions of Zn(II) salts with 4, 4ʹ-(1, 3-phenylenebis (methyleneoxy)) dibenzoic acid(pbd), 1,4-bis(imidazol-1-yl)butane (bib) and 1,10-phenanthroline (1,10-phen) co-ligands afforded two coordination polymers, [Zn(pbd)(bib)] (1) and [Zn(pbd)(1,10-phen)·4H2O] (2). The pbdcaptures the in situ generated scission product of C-O bondwith 4-(3-(hydroxymethyl)benzyloxy)benzoic acid (hbb). A new polymer of [Zn(hbb)(4,4′-bipy)](3) was also synthesized using the rigid N-donor ligand of 4,4′-bipyridine (4,4′-bpy). These polymers were characterized by IR spectroscopy, and Thermogravimetric analysis and further their structures were determined by single-crystal X-ray diffraction analysis. Compound 1 has 2D covalent network. 2 and 3 show 1D chains, which can be further interlinked into 2D supramolecular layer through π─π packing and hydrogen bonded interactions, respectively. The results indicated that 1 displayed good sensing property against most of the nitroaromatic compounds (NACs) by the decrease in its luminescent intensity. With 2,4,6-trinitrophenol (picric acid) Ksv value of 2.93 × 103 M−1 and limit of detection (LOD) of 1.24 ppm was observed. The plausible mechanism of the decline in the luminescent intensity of 1 in presence of NACs has been addressed with the help of theoretical calculations.

Carbazole is an important compound in pharmaceuticals and functional materials. A new Pd(II) supramolecular cage-catalyzed protocol for the synthesis of multifunctional carbazoles from indoles is described through regioselective successive oxidative Heck reactions. This new protocol is highly efficient, with a low Pd (2.4 mol%) catalyst loading and good compatibility for both N-H free and N-protected indole substrates. Moreover, it can be used to synthesize carbazoles with various functional groups by a one-pot two-step procedure. The excellent catalytic activity can be attributed to the distinct properties of the supramolecular cage structure in uniformly distributive and well-defined Pd(II) active centers on the cage surfaces.

A series of ten new lanthanide complexes, [Ln2(PA)6(bipy)2]·4H2O·2bipy (Ln = Eu 1, Tb 2, Ce 3, Gd 4, Nd 5, Pr 6, Sm 7, Yb 8) and [Ln2(PA)6(bipy)2]·4H2O (Ln = Ce 9 and Er 10) (HPA = 3-(4-hydroxyphenyl)propanoic acid and bipy = 2,2′-bipyridine), have been synthesized and characterized by microanalysis, FTIR and single crystal X-ray diffraction. The complexes 1–8 and 10 are isostructural and contain two crystallographically equivalent Ln3+ ions having a coordination number 9 with distorted monocapped square-antiprism geometries in which the PA ligands adopt bridging, bidentate chelating, and tridentate chelating bridging modes to coordinate with the Ln3+ ions, while complex 9 possesses a tricapped trigonal prism geometry where only bridging, bidentate chelating modes are adopted by the PA ligands. All the complexes display a 2D supramolecular layered framework held by weak C–H⋯π, π⋯π and O–H⋯O intermolecular interactions. These interactions have been validated by Hirshfeld surface analysis. Additionally, emission studies indicated that amongst all the complexes, 1 and 2 can act as luminescent sensors for the detection of nitrobenzene and Cu2+ ions. The limits of detection (LODs) using both 1 and 2 for nitrobenzene are 3.66 and 3.71 ppm, respectively and for Cu2+ ions, they are 2.11 and 2.99 ppm, respectively.

On the basis of hard soft acid base theory, two neutral heterometallic M2Pd3 supramolecular cages, [Al2Pd3(L)6Cl6] (1) and [Fe2Pd3(L)6Cl6] (2) (where HL is 1-(4-(1H-imidazol-1-yl)phenyl)butane-1,3-dione), have been constructed by using the tripodal M(L)3 as metalloligands in combination with PdCl2 or Pd(MeCN)2Cl2. The supramolecular cage can be described as a trigonal bipyramid with two M3+ ions occupying at the two axial sites in ΔΔ or ΛΛ configurations and three Pd2+ ions sitting in the three equatorial positions with square planar geometry in trans configuration. The supramolecular cages exhibit high catalytic activity for the Suzuki–Miyaura coupling with arylbromide or arylchrolide and phenylboronic acid in biorenewable solvent glycerol under mild conditions. Moreover, the catalyst can be readily recycled and reused at least five times without loss of catalytic activity. The high catalytic performance may be attributed to the distinct properties of the cage structure with uniformly distributive and well-defined Pd active centres on the cage surfaces. The high stability in the cage structure also prevents Pd leaching out and agglomeration.

A new tripodal carboxylic ligand, 2-(4-carboxylphenoxy) terephthalic acid (H3L2), readily reacts with Zn(II) salt in the presence of 4,4′-bipyridine (4,4′-bipy) to afford a new metal-organic framework of {Zn3(L2)2(μ2-H2O)(4,4′-bipy)}n (1). 1 shows 3D two-fold interpenetrating network with (3,8)-connected tfz-d topology. 1 exhibits impressive pH stability and strong luminescence, making it an excellent candidate as a fluorescent chemical sensor. It is extremely responsive to toxic heavy metal ion (Hg2+) and TNT explosive. Importantly, 1 as the luminescent probe of Hg2+ can be simply and quickly regenerated, which represents a rare example in reported luminescent sensors of Hg2+. Furthermore, the photocatalytic property of 1 for degradation of the Rhodamine B (RhB) has been examined.

A new Pb(II)-based 2D MOF comprising π-conjugated ligand 4′-(1H-tetrazol-5-yl)-[1,1′-biphenyl]-3,5-dicarboxylic acid (TZBPDC) and having the formula {[PbNa(TZBPDC)](H2O)(DMF)2}n (1) has been synthesized. Structural characterization of 1 indicates that the MOF has a 4-connected (4,4) motif. The photoluminescent investigation indicates that 1 can behave as potential luminescent sensor for the detection of nitroaromatic compounds (NACs), especially 2,4-dinitrophenol (2,4-DNP) and ferric ions, through the decrease in its luminescence intensity. Additionally, 1 also displays excellent capacity for the photodegradation of methylene orange (MO), which is a constituent of wastewater discharge. The most plausible mechanisms for the decrease in the luminescent intensity of 1 in the presence of different NACs have been explored though theoretical calculations, and the photocatalysis of 1 for organic dyes has been addressed using density of states (DOS) and partial DOS calculations.

A new tripodal carboxylic ligand, 2-(4-carboxylphenoxy) terephthalic acid, readily (H3L) reacts with Cd(II) salts in the presence of N-donor ligands to afford three different metal-organic frameworks of {Cd3(L)2(H2O)4·2CH3CN}n (1), {Cd3(L)2(2,2′-bipy)4·2H2O}n (2), and {Cd3(L)2(phen)2·2CH3CN}n (3). The structure of 1 consists of a 1D metal chain extending to three-dimensional network. The structures of 2 and 3 can be described as a repetition of a trinuclear core with subtle differences. 1–3 exhibit impressive chemical stability, pH stability and strong luminescence, making them excellent candidates as multifunctional fluorescent sensors for selective and sensitive detection of Hg2+, nitroaromatics as well as Cr2O72-. 1–3 are all extremely responsive to Hg2+ ion at a parts per million level, the limits of detection towards Hg2+ ion are 2.55 × 10−6 M, 2.72 × 10−6 M, and 9.79 × 10−7 M for 1–3, respectively. The KSV value for 3 (5.155 × 104 M−1) is the highest among most MOFs reported to date. 1–3 represent the first case on the recyclable luminescent probe for Hg2+ ion. Furthermore, the photocatalysis properties of 1–3 for degradation of the Rhodamine B (RhB) have also been examined.

Two new Zn(II) coordination polymers (CPs) with [Zn(L)(2,2′-bipy)] (1) and [Zn(L)(bbi)0.5] (2) (H2L = 3,3′-(1,2-phenylenebis(methyleneoxy)) dibenzoic acid, bbi = 1,1′-(1,4-butanediyl)bis(imidazole), 2,2,’-bipy = 2,2,’-bipyridine), have been solvothermally prepared. They exhibited 2D layer and 1D helical networks through the connectivity of Zn atoms and phenolic-oxygen containing branches of the flexible linkages. The N-donor ligand play a distinct effect in the formation of these mortifies. Both of them showed efficient photocatalytic performances to degrade methyl violet (MV) under UV irradiation. The percentage degradation of MV are 64.55% in presence of CP 1 while it is 78.54% with 2 as photocatalyst after 100 min of UV irradiation. The final degradation products were detected using LC–MS and the possible disassemble pathways for the degradation of dyes were discussed. The plausible photocatalytic mechanism through which both CPs displayed photocatalysis of MV have been explained using theoretical calculations.

An uncommon microporous metal–organic framework (MOF), {[Zn5(L)2(DMF)2(μ3-H2O)]·2DMF} (1), was successfully constructed using a less exploited symmetrical pentacarboxylate ligand, 3,5-di(3′,5′-dicarboxylphenyl)benzoic acid (H5L). The MOF 1 features a trinodal (4,5,5)-connected topology having a Schlafli symbol of (42·63·8)(45·65)2(46·64) and is stable in air as well as in acidic/basic aqueous media at room temperature. The MOF 1 behaves as a luminescent sensor for the highly selective and sensitive detection of Fe3+, Fe2+, Cu2+ and Ag+ ions and o-nitrophenol (MNP), p-nitrophenol (PNP), 2,4-dinitrophenol (DNP), 2,4,6-trinitrophenol (TNP) and 4-nitrotoluene (4-NT). Furthermore, the photocatalytic properties of 1 for the degradation of Methyl violet (MV) and Rhodamine B (RhB) have been explored. The possible quenching of the emissions of 1 in the presence of nitroaromatics has been addressed by theoretical calculations and the photocatalytic activity of 1 against organic dyes has been addressed using density of states (DOS) calculations.

An unexploited pentacarboxylate ligand, 2,5-bis(3′,5′-dicarboxylphenyl)-benzoic acid (H5L), was designed and used for the preparation of metal organic material using Zn2+ as a node. The new compound, {(Me2NH2)[Zn2(L)(H2O)]·0.5DMF}n (1) (DMF = dimethylformamide), has been synthesized and structurally characterized. The topology of the 5-connected anionic framework may be described as (44)(66) (Schlafli symbol) based on {M2(CO2)5} molecular building blocks (MBBs) and L ligands in 1. It has been demonstrated that 1 can act as a fluorescent sensor for highly sensitive detection of nitroaromatics and Fe3+, with a detection limit of 0.54 ppm for 2,4,6-trinitrophenol (TNP) and 0.81 ppm for Fe3+. The possible emission quenching mechanism in the presence of nitroaromatics has been addressed by theoretical calculations.

Two Cu-based complexes with chemical formulae {[Cu2(L)3(2,2′-bipy)2]·NO3·2H2O}(1) and {[Cu2(L)2(H2O)2(phen)2]·2NO3·H2O} (2) (HL˭3-(4-hydroxyphenyl)propanoic acid) have been synthesized and structurally characterized. Single-crystal X-ray analyses reveal that compounds 1 and 2 have dinuclear Cu(II) units linking by carboxylate groups. The chelating N-donor ligands with 2,2′-bipy and phen bind to Cu(II) centers and there are weaker Cu-Cu bond interactions as well. The detailed analyses of Hirshfeld surface and fingerprint plots provide insight into the nature of noncovalent interactions in the title compounds. Furthermore, the magnetic properties of compounds 1 and 2 and related atoms-in-molecule calculations were discussed in detail.

A new metal-organic framework of [Cu2(L)(H2O)2]·2DMF (1) (H4L = quaterphenyl-3,3′″,5,5′″-tetracarboxylic acid) has been prepared and characterized. It has the NbO-derived topology that was observed in MOF-505. Magnetic study reveals the overall antiferromagnetic interactions between neighboring Cu(II) ions in compound 1. In addition, we performed an optimization by semiempirical PM5 method simulations to investigate the loading of 5-FU to 1 at the molecular level.

A new Mn(II) complex {[Mn5(CH3COO)2(L)2(DMF)8](DMF)}n (1), (H4L = 3,5-bis(3′,5′-dicarboxylphenyl)-1H-1,2,3-triazole), has been synthesized and structurally characterized. The complex 1 have pentanuclear Mn(II) core, where the two sides of metal centers (Mn2 and Mn3) have trigonal bipyramidal arrangement and the middle metal center (Mn1) have octahedral environment utilizing two O atoms from adjacent bridging bidentate carboxylate groups and four O atoms from four coordinated DMF molecules. The planar arrangement of pentanuclear Mn(II) atoms are linked by L linkage to generate two dimensional sheet. The magnetic property of the compound indicates χM T value for the five Mn(II) unit to be 21.3 cm3 K mol−1 at 300 K, which is close to the spin-only value (21.9 cm3 K mol−1) for the pentamer having S = 5/2. Also, the Hirshfeld surface analyses have been performed which indicated the absence of weak Mn···Mn interaction thereby corroborating the results of observed magnetic properties.

A new Cu-based complex of {[Cu2(L)2(phen)2(NO3)]·NO3} (1) (HL = p-hydroxy phenylacetic acid, phen = 1,10-phenanthroline) has been synthesized and structurally characterized. Single-crystal X-ray analyses reveal that compound 1 has a dinuclear Cu(II) unit linking by two carboxylate groups and one nitrate group. The chelating N-donor ligand with phen binds to Cu(II) centers and there is weaker Cu-Cu bond interaction as well. Furthermore, the magnetic property of compound 1 was discussed in detail.

Two Zn-based complexes, namely {[Zn(L3)(2,2′-bipy)(H2O)2]n·L3} (1), and [Zn(L3)2(phen)(H2O)] (2) (HL3 = 3-(4-hydroxyphenyl)propanoic acid, 2,2′-bipy = 2,2′-bipyridine and phen = 1,10-phenanthroline), have been synthesized and structurally characterized by single-crystal diffraction analysis. Both 1 and 2 have mononuclear units, which are further linked into different 2D layers via the hydrogen bond interactions. Furthermore, the luminescent and stable properties of 1–2 are also discussed.

Two new coordination polymers (CPs) namely, [Cd2(btc)(bmi)2·4H2ODMF] (1) and [Zn2(L)(bmi)·5H2O] (2) have been synthesized utilizing mixed ligand strategy by reacting Cd(II) salt with benzene-tetracarboxylic acid (H4btc) and 1,5-bis(2-methylimidazol-1-yl)pentane (bmi) and Zn(II) salt with 5-[bis(4-carboxybenzyl)-amino]isophthalic acid (H4L) and 1,5-bis(2-methylimidazol-1-yl)pentane (bmi). The single crystal X-ray diffraction indicated that 1 has 2D network with (4,4) topology based on [Cd2(COO)4] secondary building units (SBUs), while 2 displays an undulating 2D (4, 4)-network by μ4-(L)4− ligands, which can be further interlinked into 3D supramolecular layer through hydrogen bonding interactions. Both of them have been tested as possible photocatalysts for the photodegradation of a model organic dye methyl violet (MV). The photocatalytic studies indicate that 1 and 2 show potential photocatalyts for degradation of MV. Furthermore, the possible photocatalytic mechanisms have been explained on the basis of density of states plots.

A 2D coordination polymer [Zn2(betc)(bip)2]·3H2O (1) has been synthesised by deploying mixed ligand strategy . The photoluminescence properties of 1 in different solvents have been investigated and its sensing properties to detect nitroaromatic compounds (NACs) have been explored. 1 displayed selective sensing for 4- nitrotoluene (4-NT) with lower limit of detection (LOD) 0.62 ppm. The probable mechanism for sensing of NACs by 1 ha s been addressed using quantum chemical calculations. Also photocatalytic properties of 1 to photo-decompose model aromatic dyes viz. methyl violet (MV) and 20 rhodamine B (Rh B) have been evaluated. The experiments indicated that 1 displayed better photocatalytic performance in photo-degrading MV than Rh B. The plausible mechanism through which 1 displayed photocatalytic degradation of aromatic dyes had been revealed using density of states (DOS) and partial DOS calculations. The probable mechanism for the photocatalytic property and emission quenching of 1 has been proposed with the aid of density of states and partial density of states calculations.

A new 2D Co(II) based coordination polymer (CP), {[Co2(tib)2(NO3)3(H2O)2·NO3]n (1), has been synthesized using 1,3,5-tris(1-imidazolyl)benzene (tib) ligand. The single crystal X-ray diffraction study indicates that 1 possesses an infinite 2D layer, which is further extended into a 3D supramolecular network via O–H···O hydrogen bonding interactions. Additionally, the thermogravimetric analysis (TGA) of CP indicates its decomposition temperature was about 268 °C. The UV/Vis diffuse-reflection spectrum of 1 indicates its semiconducting nature on the basis of which the photocatalytic properties of 1 against photodecomposition of organic dyes have been studied. The possible mechanism associated with the photocatalytic activity of 1 against organic dyes is addressed using density of states (DOS) calculations.

Solvothermal reaction of 1,3,5-benzenetribenzoic acid (H3btb) with metal salts yielded two compounds with chemical formulas {(Me2NH2)[Zn(btb)(DMA)]·DMA}n (1) and [Mn3(btb)2(DMA)4·4DMA] (2) (DMA = N,N′-dimethylacetamide). 1 shows a 3D 4-fold interpenetrating (6,3) topological net, which has 1-D channels with counter anion and guest DMA molecules. 2 contains a two-dimensional bilayer structure based on a carboxylate bridged Mn3 cluster. 1 has no significant adsorption for H2 and N2 gas upon desolvation by long-time thermal activation, indicating that access to the void space is blocked by the immovable anions and interpenetrated feature. In addition, the 3D luminescence for 1 and magnetism for 2 were also explored.

Solvothermal reaction of 1,3,5-benzenetricarboxylic acid (H3btc) with zinc acetate yielded a compound with chemical formulae (Me2NH2)[Zn(btc)]·H2O·DMA (1) (btc = 1,3,5-benzenetricarboxylate, DMA = N,N-dimethylacetamide). 1 shows a 3D non-interpenetrating rutile topological net, which has 1D channels located Me2NH2 counter anion and guest DMA and H2O molecules. The material has no significant adsorption for CO2 and N2 gases upon desolvation by long-time thermal activation, indicating that access to the void space is blocked by the large and immovable anions. The luminescence study indicates that the title compound emits bright red fluorescence compared to the free ligand at room temperature.

Two isostructural metal–organic polymers, namely {[M(bce)(bib)]·solv}n (M = Co(II) and solv = CH3OH·H2O for 1; M = Ni(II) and solv = 0.5CH3OH·0·25H2O for 2) (H2bce = 1,2-bis(4-carboxy-phenoxy)ethane and bib = 2,3-bis(4-pyridyl)butane), have been synthesized and characterized. The structures of the two compounds show 2D → 2D parallel interpenetrated frameworks with polyrotaxane and polycatenane character. The magnetic behaviors of 1 and 2 indicate antiferromagnetic interactions within paddle-wheel units. Furthermore, the compound 1 exhibits relative high N2 uptake adsorption capacity.

A Cd(II)-MOF, {[Cd(L)(4,4′-bipy)]·H2O·DMF}n (1) (L = nicotinic acid (2,4-dihydroxybenzylidene)-hydrazide and 4,4′-bipy = 4,4′-bipyridine), has been synthesized and characterized by microanalyses, FTIR, TGA, and single-crystal X-ray diffraction. Additionally, powder X-ray diffraction was performed to check the phase purity of the synthesized compound. Single-crystal X-ray diffraction reveals that 1 has a 2D grid network. Photoluminescent sensing of nitrobenzene, Fe(III) and CrO42− ions indicates that 1 could be a candidate for developing selective luminescent sensors for these species. Theoretical calculations have been performed to gain insight into the possible mechanism of quenching effect in emission on addition of nitrobenzene in 1 which supports the mechanism operating through ground state charge transfer between 1 and nitrobenzene.

International audience; A new compound of {[Zn(btb)(Hbib)]*2H2O*CH3OH}n (H3btb = 1,3,5-benzenetrisbenzoate and bib = 1,4- bis(2-methyl-imidazol-1-yl)butane) was synthesized and characterized. The coordination polymer shows a new (2D→3D) polythreaded array that is obtained from the self-assembly of adjacent 2D layers with dangling lateral arms, in which each large hexagonal void of one layer is threaded by two dangling lateral arms of two adjacent layers belonging to two identical spatial orientations. The luminescence study indicates that the title compound emits bright red fluorescence compared to the free ligand at room temperature. In addition, the small-sized and non-polar pores do not enable 1 to attract CO2 and N2 strongly, which can be confirmed by the computational method based on Connolly's algorithm.