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A novel anionic metal-organic framework, JUC-138, constructed by In(III) and a pyrene-based linker, H8TIAPy (H8TIAPy = 1,3,6,8-tetrakis(3,5-isophthalic acid)pyrene), has been synthesized by solvothermal reaction successfully. In JUC-138, only four carbonyl groups in each ligand connect to In3+ ions, while the others remain uncoordinated. However, each In3+ connects to four carbonyl groups in a bidentate chelate style, resulting in the formation of 2D square sheets in JUC-138. The 2D sheets interact with adjacent layers through the O-H···O hydrogen bonds between the uncoordinated carboxyl groups, thus generating the whole 3D supramolecular structure of JUC-138. UV-vis tests show the energy gap E g of JUC-138 is 3.34 eV, indicating the semiconductor nature of JUC-138. In addition, JUC-138 shows good photocatalytic activity in Azure B (AB) decolorization and could decompose 90% AB within 4 h. This photocatalytic property makes JUC-138 promising in environment governance. [ABSTRACT FROM AUTHOR]

Four uranium(VI)-polycarboxylatesframeworks with honeycomb (6,3) nets have been assembled from solvothermalsystems, which contain different guest molecules (transition metalcomplexes and methyl viologen). These compounds exhibit photocatalyticactivities for the degradation of rhodamine B. Interestingly, themethyl viologen-containing one possesses the highest efficiency, whichcan be attributed to the electron acceptor nature of methyl viologenfor the stabilization of active peroxide anions. [ABSTRACT FROM AUTHOR]

Three D–A−π–Aorganic dyes based on5,6-difluoro-2,1,3-benzothiadiazole (DFBTD) were synthesized by sequentialdirect arylation and characterized by spectroscopic and electrochemicaltechniques. Compared to 2,1,3-benzothiadiazole (BTD) analogue, thepresence of two fluorine atoms on DFBTD results not only in a significantincrease in the molar absorptivity but also in a blue shift of theonset of the absorption spectra. In the system of DFBTD-based sensitizers,replacing the thienyl unit bridge with disubstituted cyclopenta[1,2-b:5,4-b′]dithiophene (CPDT) furtherincreases molar absorptivity and decreases the oxidation potentialof the excited state E(s+/s*). Similarly,changing the indoline donor to 4-butoxy-N-(4-butoxyphenyl)-N-phenylaniline increases the optical band gap and decreasesthe oxidation potential of the excited state E(s+/s*)of the sensitizer. The correlation between the molecularstructure of these sensitizers and the photovoltaic performance ofthe dye cells were examined using current–voltage scan, incidentphoton to electron conversion efficiency (IPCE), femtosecond transientabsorption spectroscopy (TAS), and electrochemical impedance spectroscopy(EIS). The observed change of the photovoltage and photocurrent uponchanging the molecular structure of the sensitizers are discussedin terms of the charge injection from the excited state to the interbandgap states of TiO2and the charge recombination betweeninjected electrons into TiO2film and electrolyte. In all,it is found that the most efficient D–A−π–Adye achieved an open circuit voltage of 0.717 V, short circuit currentdensity of 18.8 mA/cm2, corresponding to an overall powerconversion efficiency of 9.1%. [ABSTRACT FROM AUTHOR]

An amine-free oligothiophene-based dye (BTB) featuring a tailor-made dianchoring function, a spiro-configured central unit, and bulky end-capping TIPS groups to diminish intermolecular interactions and to suppress aggregation-induced self-quenching was synthesized to achieve efficient dye-sensitized solar cells with a high power conversion efficiency of 6.52%. [ABSTRACT FROM AUTHOR]

Colloidal carbon nanospheres (CNS) with rich surfacefunctional groups of −OH and −COO–were prepared from glucose solution via hydrothermal reaction andactivated by NaOH solution. The nonporous CNS exhibited excellentadsorption performance toward basic dyes. High maximum adsorptioncapacities were obtained at 682 mg g–1for Methyleneblue, 395 mg g–1for Methyl violet 2B, and 310 mgg–1for Malachite green. Methylene blue with aninitial concentration of 94 mg L–1can be completelyremoved in 5 min at a dosage of 0.5 g L–1. Thiscan be associated with the low mass transfer resistance due to thenonporous structure and the abundant surface active sites. The adsorptionprocess is chemisorption in nature, while the kinetic data were wellfitted to pseudosecond-order kinetic model. This material presentedexcellent adsorption capacities toward basic dyes with maximum adsorptioncapacity of 682 mg g–1for Methylene blue B, 310mg g–1for Malachite green, and 395 mg g–1for Methyl violet 2B. Furthermore, the dye saturated CNS was regeneratedusing an advanced oxidation method using Co2 aqueoussolution as a homogeneous catalyst. After seven recycle runs, therewas still 96% of adsorption capacity retained. The low-cost CNS nanomaterialhas the potential to be applied as a new type of efficient adsorbentfor water treatment. [ABSTRACT FROM AUTHOR]

The surface active derivative of the organic dye Acridine Orange (N-10-dodecyl-acridine orange (DAO)) has been included in mixed Langmuir monolayers with stearic acid (SA). The maximum relative content on DAO for a stable mixed monolayer is a molar ratio of XDAO= 0.5. Brewster angle microscopy (BAM) reveals a high homogeneity at the micrometer level for the mixed monolayer in equimolar proportion (XDAO= 0.5), whereas the appearance of domains occurs for lower content of DAO, i.e., XDAO= 0.2 and 0.1. The aggregation of the DAO headgroup leads to well-defined H-aggregates at the air/water interface for those mixed monolayers with a low content of DAO. However, for the mixed monolayers enriched in DAO, e.g., XDAO= 0.5, the molecular crowding prevents the formation of defined supramolecular structures. Molecular organization and tilting of the DAO headgroup is quantitatively analyzed by in situ UV–visible reflection spectroscopy. The formation of H-aggregates of the DAO headgroup can be reversibly tuned with the applied surface pressure. A molecular mechanism for the conformational rearrangement of the DAO molecule is proposed using RM1 quantum semiempirical calculations. [ABSTRACT FROM AUTHOR]

The 1H NMR chemical shifts were theoretically computed for the organic dyes 2-(2,6-dimethyl-4H-pyran-4-ylidene)-malononitrile (1), cyano-(2,6-dimethyl-4H-pyran-4-ylidene)-acetic acid methyl ester (2), 2-(2,6-bis(4-(dimethylamino)styryl)-4H-pyran-4-ylidene)-malononitrile (3), and methyl 2-(2,6-bis(4-(dimethylamino)styryl)-4H-pyran-4-ylidene)-2-cyanoacetate (4) at the GIAO/B3LYP/6-311(d,p)//B3LYP/6-311(d,p) level of theory. Moreover, the intramolecular rotational barriers of the molecules were calculated to evaluate the internal flexibility with respect to the torsional degrees of freedom, and the nuclear-independent chemical shifts (NICS) were employed to analyze the ring currents. The difference was explained in terms of intramolecular hydrogen bonds and ring currents of the molecules. The 1H NMR spectra were reproduced by experiments for the comparison with computationally constructed data. Our results suggest a good guideline in interpreting 1H NMR chemical shifts using computational methods and furthermore a reliable perspective for designing molecular structures. [ABSTRACT FROM AUTHOR]

When an alkyl-functionalized metal-free organic dye (MK-2) was employed as a sensitizer, dye-sensitized TiO2solar cells (DSSCs) fabricated with an ionic liquid (IL) electrolyte showed an energy conversion efficiency of 7.6%, which was comparable to that with a volatile liquid electrolyte. This contrasts with the case of DSSCs employing conventional Ru complex sensitizer (N719), whose efficiency was decreased markedly when the electrolyte was replaced from the volatile to IL. As a result, with the IL electrolyte, the conversion efficiency with MK-2 was higher than that with N719. The result was mainly attributed to longer electron lifetime in the DSSCs with MK-2. The longer electron lifetime is remarkable because with conventional volatile electrolyte, the lifetimes with many organic dyes including MK-2 were shorter than that with N719. This high compatibility of MK-2 with the IL electrolyte shows that the molecular modification of organic dyes can overcome the both disadvantages of ILs and organic dyes, mostly originated from their high viscosity and from the short electron lifetime observed with volatile electrolyte, respectively. Long-term stability of the DSSCs with MK-2 and the ionic electrolyte was also investigated, showing the efficiency of more than 7% for 2000 h under 1 sun conditions. [ABSTRACT FROM AUTHOR]

Two isomeric two-dimensional copper(I) coordination polymer materials based on an in situ generated 5-(3-pyridyl) te trazole ligand show similar layer structures but distinct photoluminescent and photo-catalytic properties, which present an interesting com-parative study on the structure--property correlation between isomeric materials. [ABSTRACT FROM AUTHOR]