Search

Three new heteroleptic 1,2-bis(diphenylphosphino)ethane (dppe) appended Co(III) ferrocene dithiocarbamate complexes with the formula [Co(dppe)(Fcdtc)]PF6 ((Fcdtc = N-benzyl-N-methylferrocene dithiocarbamate (Co-FcBz), N-2-methylpyridyl-N-methylferrocene dithiocarbamate (Co-FcPy) and N-ethanol-N-methylferrocene dithiocarbamate (Co-FcEtOH); dppe = 1,2-bis(diphenylphosphino)ethane) have been synthesized and characterized by microanalyses, FTIR spectroscopy, electronic absorption spectroscopy and single crystal X-ray diffraction. Single crystal X-ray diffraction revealed that the geometry around Co(III) in the Co-FcBz and Co-FcEtOH complex cations is distorted octahedral and satisfied by four sulfur atoms of two dithiocarbamate ligands and two phosphorus atoms of the dppe ligand. The weak interactions existing in Co-FcBz and Co-FcEtOH have been addressed with the help of Hirshfeld surface analysis. The electronic absorption spectra of all three compounds display bands in the regions of ∼400–500 nm and ∼500–750 nm which are due to the d–d transition of ferrocene and Co(III), respectively. These compounds have been used as photo-sensitizers in dye-sensitized solar cells (DSSCs). Experiments revealed that amongst all three sensitizer-based DSSC set-ups, the assembly fabricated using Co-FcEtOH exhibited the best photovoltaic performance with 3.89% efficiency (η), a short circuit current (Jsc) of 9.15 mA cm−2, an open circuit voltage (Voc) of −0.680 V and an incident photon-to-current conversion efficiency of 49%. Also, the ageing experiment for the DSSC set-up fabricated using Co-FcEtOH revealed that after 100 h, the set-up retained 97% of its efficiency, which indicates that such a class of molecular systems can be used as apt sensitizers for DSSC fabrication. [ABSTRACT FROM AUTHOR]

Metal–organic frameworks (MOFs), a sub-class of well-known coordination polymers, are assorted multidimensional materials that can be employed as photocatalysts for the decomposition of aromatic dyes present in wastewater discharge. Herein, two new Cd(II) MOFs [Cd7(L)4(μ2-OH)2(H2O)4(bbi)3] (1) and [Cd3(L)2(bbm)2] (2) (H3L = 3-(4-carboxyphenoxy)-5-methylbenzoic acid, bbi = 1,4-di(1H-imidazol-1-yl)butane and bmp = 1,3-bis(2-methylimidazolyl)pentane) have been synthesized and characterized. Single-crystal X-ray diffraction analysis reveals that 1 possesses a 3D (3,16)-connected pillar-bilayer network with a {32·4}2{38·450·534·624·74} topology and comprises [Cd7(COO)14] SBUs. Meanwhile, 2 exhibits a 2D (3,8)-connected framework with a {3·42}2{34·46·56·68·73·8} topology comprising [Cd3(COO)6] SBUs. Both MOFs have been used as photocatalysts for the photodegradation of aromatic dyes, and experiments demonstrate that 1 and 2 exhibit 95.5% and 86.2% photodegradation of methyl violet (MV), respectively, in a time span of 100 min. Moreover, both MOFs offer better photodegradation of MV than other model dyes such as rhodamine B, methyl blue and methyl orange. Additionally, the effects of catalyst amount and dye concentration on dye degradation have been explored. Further, trapping experiments indicate that ˙OH and ˙O2− are the active species responsible for the degradation of MV in the presence of 1. Both MOFs could be recycled and used repeatedly as photocatalysts for the degradation of MV, which showcases their highly stable nature. Density of states plots and Hirshfeld surface analyses have been performed to address the plausible photocatalytic mechanistic pathways. [ABSTRACT FROM AUTHOR]

The reaction between di-n-butyltin(IV) chloride with the dinegative dithiolate ligand 2-(cyanobenzo)nitrile-dithiolate in two different alcoholic media viz. methyl alcohol and ethyl alcohol fortuitously yielded di-n-butyltin(IV)-bis-(1-methoxy-isoquinoline-4-nitrile thiolate) (Sn-Me) and di-n-butyltin(IV)-bis-(1-ethoxy-isoquinoline-4-nitrile thiolate) (Sn-Et). Similarly the reaction of di-n-butyltin(IV) chloride with 2-methoxy phenyl acetonitrile dithiolate yielded di-n-butyltin(IV)-2-methoxy phenyl acetonitrile dithiolate (2-MeCN-Sn). These compounds have been characterized by micro analyses, IR, UV-vis, 1H, 13C and 119Sn NMR spectroscopy as well as by single crystal X-ray diffraction technique in case of Sn-Et, Sn-Me. The X-ray analyses revealed that in both Sn-Me and Sn-Et, the Sn(IV) center adopts a skew trapezoidal bipyramidal geometry with Sn at the centre and two sulfur and two ring nitrogen atoms of 1-alkoxy-isoquinoline-4-nitrile thiolates are at the corners of a trapezoid with two n-butyl groups adopting axial positions resembling the cis–trans pathway. Both Sn-Me and Sn-Et display varied types of non-covalent interactions. The nature of these interactions has been addressed with the aid of Hirshfeld surface analysis, density functional theory and quantum theory of atoms-in-molecules (QTAIM) analyses. [ABSTRACT FROM AUTHOR]

A new heteroleptic nickel(II) complex, [Ni(dppe)(acac)]·CHCl3 (1) (where acac = acetylacetonatedithiolate, dppe = 1,2-bis(diphenylphosphino)ethane), has been synthesized and characterized using different spectroscopic techniques and single-crystal X-ray diffraction. The solvothermal decomposition of the complex in two different solvents, viz. 1-dodecanethiol (DT) and octadecyl amine (ODA), yielded two different nickel sulfides, viz.Ni-DT and Ni-ODA, respectively. These sulfides have been characterized by PXRD and SEM. Rietveld refinement analyses of Ni-DT revealed that it comprises two phases of nickel sulfide, viz. NiS and Ni3S3, while Ni-ODA possesses only a single phase of Ni2S3. The newly synthesized materials have been used as electrocatalysts for the oxygen evolution half-cell reaction of water splitting. The electrochemical studies suggest that Ni-DT/Ni-ODA has a good electrocatalytic activity towards the OER at a low overpotential of ∼200 mV with η1 being 342 mV and 243 mV for Ni-DT and Ni-ODA, respectively, at a scan rate of 1 mV s−1. [ABSTRACT FROM AUTHOR]

Coordination polymers (CPs) are an assorted class of multidimensional materials which can be employed as photocatalysts against the photodegradation of toxic aromatic dyes existing in wastewater discharge. Herein, two new coordination polymers with formulas [Cd3(L)2(μ2-H2O)(H2O)·2H2O] (1) and [Cd(HL)(H2O)(phen)·H2O] (2) have been derived from Y-shaped tricarboxylate ligand 1,3,5-tris(4-carbonylphenyloxy)benzene (H3L) and 1,10-phenanthroline (phen) as a co-ligand. The single crystal X-ray diffraction studies revealed that 1 presents a 3D pillar-layer framework, which contains a 1D stair-type chain and 2D layer. CP 2 displays wave-like 1D chains which link to each other to create a 2D architecture through hydrogen-bonding interactions. The introduction of the chelating N-donor ligand led to significant differences in the final frameworks. Both CPs exhibited efficient photocatalytic performance for the degradation of organic dyes viz. methyl violet (MV), methyl orange (MO), methylene blue (MB) and rhodamine B (RhB) under UV irradiation. Moreover, a possible photocatalytic mechanism via trapping experiments of active species has been proposed. In addition, a mechanistic study towards better understanding of the photocatalytic degradation of dyes has been accomplished through LC-MS studies. Also, computationally using band gap calculations, the probable mechanistic pathway has also been proposed which has been further corroborated with Hirshfeld surface analysis. [ABSTRACT FROM AUTHOR]

In this report, the composites of anionic complex [NEt4][Ni(S2C2Ph2)2] with two-dimensional materials such as graphene oxide (GO), reduced graphene oxide (rGO) or graphitic carbon nitride (g-C3N4) have been prepared by a simple sonochemical technique and utilized for the oxygen evolution half-cell reaction of water splitting. The synthesized complex anion has been characterized spectroscopically and by single-crystal X-ray diffraction, while its composites with GO, rGO and g-C3N4 have been characterized using physicochemical characterization techniques, viz. powder X-ray diffraction and scanning electron microscopy. Electrochemical measurements were performed on a three-electrode system having a platinum wire counter electrode, a Ag/AgCl reference electrode and a catalytically modified glassy carbon electrode using linear sweep voltammetry, cyclic voltammetry and electrochemical impedance spectroscopy. The electrochemical studies suggest that the [Ni(S2C2Ph2)2]-rGO modified electrode had notable electrocatalytic activity for the oxygen evolution reaction (OER). The fabricated electrode exhibited acceptable repeatability, reproducibility and stability. To the best of our knowledge, there are only a few reports on detailed studies of composites of 2D materials with a nickel-based molecular complex, exhibiting substantial synergistic activity towards electrochemical water splitting. [ABSTRACT FROM AUTHOR]

Coordination polymers (CPs) have emerged as a peculiar category of multidimensional materials used as photocatalysts for assorted classes of lethal aromatic dyes. Herein, two new d10-configuration based coordination polymers with formula [Zn(L)(bip)·H2O] (1) and [Cd3(L)3(bip)2(H2O)2] (2) (H2L = 1,3-bis(4′-carboxylatophenoxy)benzene and bip = 3,5-bis(1-imidazoly)pyridine) have been reported and characterized using microanalyses, FTIR and single crystal X-ray diffraction. The X-ray analysis reveals that the Zn(II) based CP 1 has a 2D supramolecular framework built by hydrogen bonds as well as packing interactions between adjacent chains having a 3-nodal topology with a Schläfli notation of (4·84·12)(4)(8). Meanwhile, the Cd(II) based CP 2 exhibits a three-dimensional (3D) 2-fold interpenetrating network, having a 4,6-c net topology with a Schläfli notation of (44·610·8)(44·62). Both the materials have been used as photocatalysts for UV light assisted photodegradation of aromatic dye methylene blue (MB). The photocatalysis experiments indicate that the percentage degradation of MB is 35.92% and 72.02% in the presence of CPs 1 and 2, respectively, for a time period of 100 min, while in the absence of these CPs the percentage degradation is merely 11.49%. A mechanistic study towards understanding of the photocatalytic degradation of MB was carried out using LC–MS studies and computationally using band gap calculations; a probable mechanistic pathway has also been proposed which was further complimented with Hirshfeld surface analysis. [ABSTRACT FROM AUTHOR]

Three new one dimensional ferrocene decorated Hg(II) based coordination polymers with the general formula of (FcCH2N(C2H4OH)NCS2HgX)n {X = Cl (FcHgCl); Br (FcHgBr); I (FcHgI)} have been synthesized using a functionalized dithiocarbamate ligand with a redox active ferrocene pendant and –C2H4OH and have been characterized by microanalyses, FTIR, 1H, 13C, and 199Hg NMR, electronic absorption and photoluminescence spectroscopy. The redox properties of these compounds have been assessed by cyclic voltammtery which suggested their quasi-reversible redox behaviour. Single crystal X-ray diffraction studies suggested that the geometries around all three Hg(II) polymers are square pyramidal and two such square-pyramids fuse in an antiparallel mode in FcHgCl and FcHgI and in an orthogonal mode in FcHgBr to generate a ferrocene decorated 1D polymeric framework. The adjacent 1D polymeric chains in all three compounds are held by different intermolecular interactions which provide stability to these compounds in the solid state. Also, these compounds exhibit interesting Hg⋯X (X = Cl, Br and I) spodium bonding interactions. The nature of all these interactions have been studied by Hirshfeld surface analyses, density functional theory and quantum theory of atoms in molecules (QTAIM). The QTAIM results indicated that Hg⋯X interactions are moderately strong with interaction energies of 9.32, 44.37 and 19.56 kJ mol−1 for chloro, bromo and iodo derivatives, respectively. Further bond order calculations also suggest the presence of spodium bonding interaction in all three polymers. [ABSTRACT FROM AUTHOR]

Porous crystalline materials (PCMs) constitute a class of covalent or supramolecular coordination architectures having intensive application in the fields of sensing, gas separation and storage, catalysis and optoelectronic device engineering. The theoretical investigations on these porous crystalline systems using multiple wave functions add fundamental insights into better understanding of highly selective sensing. A lot of recent reports focus on various archetypal luminescent porous organic frameworks, like metal organic frameworks (MOFs), covalent organic frameworks (COFs), or nanocomposites having excellent luminescence sensing performance against a plethora of nitroaromatic compounds and explosives. These exceptional classes of compounds display unique characteristic photochromism and electronic properties which can be tuned from the grass-root level by modifying metal–ligand interactions and various supramolecular interactions at the molecular level. Thus, developing luminescent porous organic frameworks having ultra-fast capacity of sensing nitroaromatic compounds and explosives reversibly with high selectivity and low limits of detection (LOD) is urgently required for national security, as well as homeland and environment safety. The reusability of these porous frameworks can only be anticipated if the crystallinity of these materials is retained after repeated use followed by construction of these frameworks with cheaper starting materials. The present review mainly encompasses the recent progress in various luminescent PCMs incorporating transition metals, lanthanides, nanocomposites, and main group elements having sensing technology applications along with the theoretical insights and possible mechanisms behind "turn-on" or "turn-off" luminescence. [ABSTRACT FROM AUTHOR]

Three new 1D coordination polymers (CPs) containing diorganotin(IV) moieties, viz. dimethyltin(IV) (1), di-n-butyltin(IV) (2) and diphenyltin(IV) (3) coordinated to a dinegative dithiolate ligand derived from benzyl cyanide have been synthesized and characterized using elemental analyses, FTIR, 1H, 13C and 119Sn NMR spectroscopy and UV-vis spectroscopy. Single-crystal X-ray diffraction studies for coordination polymers 1 and 2 indicated that the immediate geometry around Sn(IV) in both the CPs is close to being both distorted square pyramidal and distorted trigonal bipyramidal as suggested by the index of the trigonality (τ5) parameter which is satisfied by two aliphatic fragments, two sulfurs of the dithiolate ligand and cyano nitrogen of another dithiolate ligand. The supramolecular architecture in 1 is stabilized by interesting C⋯Sn interactions along with C–H⋯C, C–H⋯S and C⋯S interactions, while in 2, C–H⋯S, S⋯S and C–H⋯π interactions stabilize the solid-state structure. The weak interactions in both compounds have been addressed with the aid of Hirshfeld surface analyses as well as fingerprint plots and further these interactions have been addressed using quantum theory of atoms in molecules (QTAIM) and DFT studies. Also, TGA for all the three compounds indicated that they can also be used as single source precursors for tin sulfides. [ABSTRACT FROM AUTHOR]

A new d10-configuration based Zn(ii) 3D metal–organic framework (MOF) with the formula {[Zn4(NDC)3.5(μ4-OH)(DMF)]·1.7DMF}n (1) has been synthesized using a 1,4-naphthalenedicarboxylic acid (H2NDC) ligand and characterized. The single crystal X-ray diffraction results indicate that in the newly synthesized MOF, 7-connected [Zn4(μ4-OH)(COO)7] clusters are formed which are extended by NDC2− ligands to generate an uncommon sev topology. The photocatalytic properties of 1 in the photodegradation of model organic dyes viz. methyl violet (MV) and rhodamine B (Rh B) have been systematically investigated. The photocatalysis results demonstrated that 1 shows promising photocatalytic degradation activity against these organic dyes. The possible photocatalytic mechanism through which 1 displayed photocatalytic properties to photodegrade organic dyes has also been proposed with the aid of density of states (DOS) calculations. [ABSTRACT FROM AUTHOR]

Three new ferrocenyl oxadiazoles, viz. (E)-2-(4-hydroxyphenyl)-5-(2-ferrocenyl-ethen-1-yl)-1,3,4-oxadiazole (D2), (E)-2-(4-nitrophenyl)-5-(2-ferrocenyl-ethen-1-yl)-1,3,4-oxadiazole (D3) and (E)-3-(4-nitrophenyl)-5-[5-(2-ferroceneylethen-1-yl)-1,3,4-oxadiazol-2-yl]-1,2,4-oxadiazole (D4) derived from (E)-3-ferrocenylacrylic acid (D1) having phenolic or nitro anchors, have been synthesized and characterized using microanalyses and relevant spectroscopic techniques. UV-Vis spectroscopic studies indicate that with respect to ferrocene, the electronic absorption bands of the new compounds are bathochromically shifted up to 600 nm with a concomitant enhancement in their intensities. All four compounds have been used as photosensitizers in TiO2-based dye-sensitized solar cells (DSSCs). The photovoltaic performances and charge transport properties (EIS spectra) of these compounds were studied to appraise their dye performance. All four compounds displayed good photovoltaic performances. However, compounds D2 and D4 displayed superior performance, which might be due to the better electronic communication between the ferrocenyl moiety and the six membered aromatic ring with their –OH/NO2 anchors having five membered oxadiazole spacers, as well as the high dye loading of these compounds on the TiO2 surface, which suppresses charge recombination, prolongs electron lifetime, and decreases the total resistance of DSSCs. The assembly fabricated using D4 performed better with an overall conversion efficiency η of 4.70%, Jsc of 10.33 mA cm−2 and Voc of −0.712 V. [ABSTRACT FROM AUTHOR]

Three isomeric bis-(triphenylphosphine)copper(i) complexes comprising xanthate ligands derived from 2- (1), 3- (2), and 4-methanol pyridine (3) have been synthesized and characterized using microanalyses, IR, multinuclear NMR, UV-Vis and fluorescence spectroscopic methods as well as single crystal X-ray diffraction. The single crystal X-ray diffraction results indicated that the immediate geometry around Cu(i) in the complexes is distorted tetrahedral, which is satisfied by the two sulfur centers of the xanthate ligands and two phosphorus centers of the two PPh3 moieties. Additionally, thermogravimetric analysis (TGA) under an inert atmosphere was performed, and the results indicated that the complexes decompose to copper sulfide. The complexes were decomposed under an inert atmosphere to obtain copper sulfides, which were characterized by PXRD and SEM. Additionally, their electrocatalytic properties were investigated in the oxygen evolution reaction (OER). The OER results indicate that the copper sulfide (CuxS-3) obtained from 3 exhibited the best activity with an onset potential of 475 mV. [ABSTRACT FROM AUTHOR]

The articulate combination of intriguing functional groups and luminescence properties can deliver metal–organic frameworks (MOFs) with multifarious applications viz. selective and specific sensing of nitroaromatic compounds (NACs), an important constituent of explosives, as well as sensing of toxic metal ions. In this regard, a new d10 configuration based Zn(ii) metal–organic framework (MOF) {(NH2(CH3)2)[Zn4(ddn)2(COO)(H2O)4]·solvent}n (1) has been synthesized using a π-conjugated and rigid multicarboxylate ligand 3,5-di(3,5-dicarboxylphenyl)nitrobenzene (H4ddn). 1 displays a 3D (3,4,6)-c connected net which is based on two types of binuclear [Zn2(μ2-COO)2(μ1-COO)2] and [Zn2(μ2-COO)4] clusters. Sensing studies of 1 to detect nitro-aromatic compounds reveal highly specific detection of 2,4-dinitophenol (DNP) with remarkable quenching (KSV = 8.93 × 103 M−1) and a low limit of detection (LOD: 1.12 ppm). The luminescence quenching mechanism in the case of 1 in the presence of NACs has been ascribed to the concurrent presence of the charge transfer as well as the weak interaction between the MOF and NACs. The activated framework of 1 also displayed highly selective detection of ferric ions with KSV = 1.13 × 104 M−1 with a low limit of detection (LOD: 1.24 ppm). [ABSTRACT FROM AUTHOR]

Herein, two new Ni(dppf)dithiolates in which dithiolate ligands comprise 2,2-diacetyl (D-1) and 2-nitro (D-2) anchors have been synthesized and characterized using microanalyses, FTIR, 1H and 13C NMR spectroscopy, as well as single-crystal X-ray diffraction. The X-ray crystallographic studies indicate that in both compounds, the geometry around the Ni(ii) center can be described as distorted square planar, which is defined by the two sulfur centers of the dinegative dithiolate ligands and two phosphorus centers of the neutral dppf ligand. The electronic absorption spectra for both sensitizers display a blue shift when compared with the characteristic electronic absorption spectrum of the dppf ligand in a similar wavelength region. The photovoltaic performances and charge transport properties (EIS spectra) were studied to evaluate the performance of the synthesized dye in DSSCs. Upon comparing both dyes, it was found that the dye with the nitro anchor (D-2) showed better photovoltaic performance than the dye with the ketonic anchor (D-1). The superior performance of D-2 suggests better anchorage and superior dye loading capability on the TiO2 surface, which suppresses charge recombination, prolongs electron lifetime, and decreases the total resistance of DSSCs. The assembly fabricated using D-2 showed best performance with an overall conversion efficiency, η, of 3.21%, Jsc of 7.96 mA cm−2, and Voc of −0.654 V. The obtained efficiency is ∼46% that of today's state-of-the-art N719 dye under similar conditions. The probable reasons for the poor performance of both dyes have been addressed with the help of theoretical calculations. [ABSTRACT FROM AUTHOR]

A new Zn(ii) metal–organic framework, formulated as {[Zn(L)]·2.7 DMF} (1), was synthesized using a multidentate ligand 1,4-bis(triazol-1-yl)terephthalic acid (H2L). The MOF 1 adopts 3D uninodal 4-c CdSO4 topology and behaves as a luminescent chemosensor for highly selective and sensitive detection of Fe3+ and nitro-aromatics, particularly 2,4,6-trinitrophenol (TNP). In addition, the thermal stability, UV/Vis diffuse-reflection spectra and photocatalytic behaviors of 1 against organic dyes have also been investigated. The possible mechanism associated with the alleviation in the emission intensity of 1 in the presence of nitro-aromatic compounds were addressed by theoretical calculations. In addition, the photocatalytic activity of 1 against organic dyes was addressed using density of states (DOS) calculations. [ABSTRACT FROM AUTHOR]

A new Cd(ii) based metal–organic framework (MOF), having formula {(CH3)2NH2)6[Cd5(L)4]·H2O·3DMF}n (1), has been synthesized based on a rigid tetracarboxylate ligand of terphenyl-3,3′′,5,5′′-tetracarboxylic acid (H4L). 1 shows a complicated 3D tetranodal 3,3,4,8-c network with uncoordinated –COO− groups. The highly selective luminescent sensing of 2,4-dinitrophenol (2,4-DNP), 2,4,6-trinitrophenol (TNP) and ferric ions was studied for 1 through the alleviation in its fluorescence intensity. The detection limit of 2,4-DNP was found to be 0.84 ppm, which is 20 times higher than that of 1,3,5-trimethylbenzene, demonstrating greater and selective quenching ability. The possible mechanism associated with the decrease in fluorescence intensity of 1 in the presence of nitroaromatics (NACs) has been addressed by theoretical calculations. Furthermore, 1 displays excellent capacity to adsorb methylene blue (MB) with high selectivity, and it maintains an almost identical adsorption performance after being recycled five times. [ABSTRACT FROM AUTHOR]

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 Schläfli 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. [ABSTRACT FROM AUTHOR]

Two ferrocenyl benzimidazoles with carboxylic (1) and nitro (2) anchors have been synthesized and characterized using microanalyses, IR, 1H and 13C NMR spectroscopy, and in one case using single crystal X-ray diffraction. UV-Vis spectroscopic studies indicate that in comparison to ferrocene the electronic absorption bands of the synthesized 1 and 2 dyes are bathochromically shifted up to 530 nm with concomitant enhancement in their intensities. The synthesized dyes have been exploited as a photosensitizer in TiO2-based dye-sensitized solar cells (DSSCs). The photovoltaic performances and charge transport properties (EIS spectra) were studied to evaluate the synthesized dye performance in DSSCs. Amongst both the dyes, the one with the carboxylic anchor showed relatively superior photovoltaic performance in comparison to the dye with a nitro anchor. The superior performance of 1 is probably due to the better anchorage and superior dye loading capability on the TiO2 surface, which suppresses charge recombination, prolongs electron lifetime, and decreases the total resistance of the DSSC. The assembly fabricated using 1 showed the best performance with an overall conversion efficiency η of 5.81%, Jsc of 12.74 mA cm−2, and Voc of −0.648 V. The obtained efficiency is ∼84% of the cell efficiency compared with the state-of-the-art N719 dye in similar conditions. [ABSTRACT FROM AUTHOR]

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) (Schläfli 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. [ABSTRACT FROM AUTHOR]

Three new coordination polymers (CPs) viz. [Zn2(L)]n (1), {[Cd3(L)2(H2O)][Na2(μ2-H2O)(H2O)7]}n (2) and [Zn2(L)(phen)2(H2O)·H2O]n (3) were synthesized by the reaction between 5-[bis(3-carboxybenzyl)-amino]isophthalic acid (H4L) Zn(NO3)2 (1)/Cd(NO3)2 (2) or Zn(NO3)2 and H4L in the presence of 1,10-phenanthroline (phen) (3) and characterized. X-ray single-crystal analyses reveal that 1 possesses a 3D architecture with a {4·62}{4·82}{42·65·88} topology, whereas 2 shows a unique (4,8)-connected 3D framework with a {411·615·82}{45·6}{46} topology. In the case of 3, the L and phen ligands linked the Zn(ii) atoms into a deeply corrugated 2D sheet. The results showed that the structural diversity of the polymers resulted from the different geometries of the metal ions and the effect of the assistant ligands. The photoluminescence sensing of nitro-aromatics by 1–3 indicates that these CPs could be prospective candidates for developing luminescence sensors for selective sensing of these species. Theoretical and experimental investigations indicate that the observed quenching in the photoluminescence intensities of 1–3 by nitro-aromatics may be assigned to the occurrence of both electron and energy transfer processes, in addition to electrostatic interaction between the CPs and nitro-aromatics. [ABSTRACT FROM AUTHOR]