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Combined experimental and computational analyses were carried out with the aim of developing a cost-effective and sustainable electrolyte solution based on a deep eutectic solvent (DES) for dye-sensitized solar cells (DSSCs). A mixture of choline chloride (CholCl, 1 mol) and ethylene glycol (EG, 2 mol) as a DES was used in combination with MeCN, lithium iodide, 1-ethyl-3-methylimidazolium iodide (Emim), and iodine as DSSC electrolytes on TiO2 and Pt electrodes. It is noteworthy that in this work the effects of various conditions, namely, the amount of MeCN and the molar concentration of I-2, LiI, and EmimI and the 4-tert-butylpyridine (TBP) additive on the photovoltaic performance of DSSCs were evaluated. Optimization of the DSSC performance using photocurrent density-voltage plots allowed reaching an efficiency of 9.26% with an electrolyte solution comprising LiI (1.1 M), EmimI (0.5 M), and I2 (0.04 M), and 60:40 v/v of CholCl/EG DES and MeCN. Addition of TBP to the electrolyte allowed reaching even 9.48%, both are unprecedentedly high values. Density functional theory geometry optimizations and molecular dynamics simulation calculations generated an insightful set of information about the intensity of the interactions between electrolyte components with each other in solution and with the TiO(2 )or Pt solid surfaces. From mean square displacement curves, diffusion coefficients (x10(-11) m(2)/s) were found to increase along the series Li+ (0.82) < Emim+ (1.01) < Chol(+) (1.15) < Cl- (1.29) < I-(1.74) < EG (5.99) < MeCN (102.92) in line with the experimental data. Li+ solvation vs Li+ adsorption on the TiO2 or Pt surface is the main interaction governing the efficiency with a high rate of localization, improving the performance. Our results provide a deep understanding of the molecular interactions at the interfaces of the DES and might pave the way for the fabrication and design of optimized DES-based electrolytes for photovoltaic processes.

Titanium dioxide (TiO2) nanotubes are attractive materials for drug-delivery systems because of their biocompatibility, chemical stability, and simple preparation. In this study, we loaded TiO2 nanotubes with anticancer drug doxorubicin (DOX) experimentally and in all-atom molecular dynamics (MD) simulations. The release of doxorubicin from the nanotubes was studied by high-performance liquid chromatography (HPLC) and confocal Raman spectroscopy, and drug-release profiles were evaluated under various conditions. The polyethylene glycol (PEG) coating and capping of the nanotubes led to a marked increase in the water contact angles from about 16 to 33 degrees in keeping with reduced wettability. The capping retarded the release rate without decreasing the overall release amount. The MD simulations further show that the DOX molecule diffusion coefficients (Di) are in the order of 10(-10) m(2)/s. The DOX molecules show a plethora of short- and long-range H-bonding interactions with TiO2 nanotube walls and water. Calculated radial distribution functions (RDFs) and combined radial/angular distribution functions (CDFs) allowed gauging the strength of these hydrogen bonds. The strength does not fully correlate with the pKa values of DOX atoms which we assign to the confinement of DOX and water in the tubes. The lifetimes of hydrogen bonds between the DOX atoms and water molecules are shorter than that of the DOX center dot center dot center dot TiO2 interactions, and DOX center dot center dot center dot DOX aggregation does not play an important role. These results suggest TiO2 nanotubes as promising candidates for controllable drug-delivery systems for DOX or similar antiproliferative molecules.

Titanium dioxide (TiO2) nanotubes are attractive materials for drug-delivery systems because of their biocompatibility, chemical stability, and simple preparation. In this study, we loaded TiO2 nanotubes with anticancer drug doxorubicin (DOX) experimentally and in all-atom molecular dynamics (MD) simulations. The release of doxorubicin from the nanotubes was studied by high-performance liquid chromatography (HPLC) and confocal Raman spectroscopy, and drug-release profiles were evaluated under various conditions. The polyethylene glycol (PEG) coating and capping of the nanotubes led to a marked increase in the water contact angles from about 16 to 33 degrees in keeping with reduced wettability. The capping retarded the release rate without decreasing the overall release amount. The MD simulations further show that the DOX molecule diffusion coefficients (Di) are in the order of 10(-10) m(2)/s. The DOX molecules show a plethora of short- and long-range H-bonding interactions with TiO2 nanotube walls and water. Calculated radial distribution functions (RDFs) and combined radial/angular distribution functions (CDFs) allowed gauging the strength of these hydrogen bonds. The strength does not fully correlate with the pKa values of DOX atoms which we assign to the confinement of DOX and water in the tubes. The lifetimes of hydrogen bonds between the DOX atoms and water molecules are shorter than that of the DOX center dot center dot center dot TiO2 interactions, and DOX center dot center dot center dot DOX aggregation does not play an important role. These results suggest TiO2 nanotubes as promising candidates for controllable drug-delivery systems for DOX or similar antiproliferative molecules.

All-atom molecular dynamics (MD) simulations were performed to systematically analyse the distribution and agglomeration of a series of small neuroprotective N-(3-anilinopropyl)-9H-carbazole based molecules at octanol/water interfaces along with a detailed assessment of their structural and dynamical properties, such as density profiles, distribution functions, average orientations, hydrogen bonding (H-bonding), and mean-square displacements. Our simulations show that the biologically active neuroprotective molecules easily migrate from the water phase to the octanol phase during the simulation trajectories. However, biologically inactive derivatives agglomerated in the water phase. Calculated radial distribution functions (RDFs) clearly underpin the necessity of the two 3,6-dibromo substituents on the carbazole core for a sufficient hydrophobic character. Furthermore, we could show that H-bonding from F, or OH groups located on the propyl unit with octanol or water molecules are decisive structural requirements for their distribution between the two liquid phases.

Drug delivery systems sensitive to pH have been investigated recently as a responsive strategy for tumour targeting in view of the slightly acidic pH environment of most solid tumours. Herein, we report Zn capped Al(2)O(3)and TiO(2)nanoporous arrays for pH sensitive drug release. The nanostructures were fabricated through electrochemical anodisation. Vitamin C as a model drug was loaded into the nanopores; some were then capped using elemental Zn. The release rates of vitamin C were investigated in water or lactic acid using high performance liquid chromatography (HPLC). The amount of drug loaded into the nanostructures was about 7 times higher for TiO(2)compared with Al(2)O(3)and the release was faster from TiO2. Zn capping proved to be quite efficient at preventing release at high pH (7) and not largely hindering the release at low pH (5), making both systems suitable for pH-triggered release. Molecular dynamics (MD) simulations showed that the diffusion of vitamin C molecules through the model nanopores is faster for TiO(2)than for Al2O3, consistent with the experimental results. The tremendously stronger H bonding interactions observed for vitamin C molecules and water molecules with the TiO(2)walls compared with Al(2)O(3)are responsible for the observed differences in the calculated number density profiles and radial distribution functions.

All-atom molecular dynamics (MD) simulations were performed to systematically analyse the distribution and agglomeration of a series of small neuroprotective N-(3-anilinopropyl)-9H-carbazole based molecules at octanol/water interfaces along with a detailed assessment of their structural and dynamical properties, such as density profiles, distribution functions, average orientations, hydrogen bonding (H-bonding), and mean-square displacements. Our simulations show that the biologically active neuroprotective molecules easily migrate from the water phase to the octanol phase during the simulation trajectories. However, biologically inactive derivatives agglomerated in the water phase. Calculated radial distribution functions (RDFs) clearly underpin the necessity of the two 3,6-dibromo substituents on the carbazole core for a sufficient hydrophobic character. Furthermore, we could show that H-bonding from F, or OH groups located on the propyl unit with octanol or water molecules are decisive structural requirements for their distribution between the two liquid phases.

Drug delivery systems sensitive to pH have been investigated recently as a responsive strategy for tumour targeting in view of the slightly acidic pH environment of most solid tumours. Herein, we report Zn capped Al(2)O(3)and TiO(2)nanoporous arrays for pH sensitive drug release. The nanostructures were fabricated through electrochemical anodisation. Vitamin C as a model drug was loaded into the nanopores; some were then capped using elemental Zn. The release rates of vitamin C were investigated in water or lactic acid using high performance liquid chromatography (HPLC). The amount of drug loaded into the nanostructures was about 7 times higher for TiO(2)compared with Al(2)O(3)and the release was faster from TiO2. Zn capping proved to be quite efficient at preventing release at high pH (7) and not largely hindering the release at low pH (5), making both systems suitable for pH-triggered release. Molecular dynamics (MD) simulations showed that the diffusion of vitamin C molecules through the model nanopores is faster for TiO(2)than for Al2O3, consistent with the experimental results. The tremendously stronger H bonding interactions observed for vitamin C molecules and water molecules with the TiO(2)walls compared with Al(2)O(3)are responsible for the observed differences in the calculated number density profiles and radial distribution functions.

The pyridine-2,6-carboxylic esters pydicR(2) with R = Me or Ph form the unprecedented mononuclear Cu-II complexes [Cu(pydicR(2))Cl-3](-) in one-pot reactions starting from pyridine-2,6-carboxychloride pydicCl(2), Cu-II chloride, and NEt3 in MeOH or PhOH solution under non-aqueous conditions. The triethylammonium salts (HNEt3)[Cu(pydicR(2))Cl-3] were isolated. The methyl derivative could be crystallized to allow a XRD structure determination. Both structures were optimized using DFT calculations in various surroundings ranging from gas phase and the non-coordinating solvent CH2Cl2 to the weakly coordinating acetone and well-coordinating solvents acetonitrile (MeCN) or dimethylformamide (DMF), while detailed calculation showed the charge distribution, dipole moments, and HOMO-LUMO gap energies changing upon solvation. According to these calculations, the ion pairs and the anionic Cu-II complexes were stable, which shows only Cu-Cl bond elongation and weakening of the charge transfer between the anionic complex and the cation as solvents become polar. Synthesis attempts in the presence of water yielded the Cu-II complexes [Cu(pydic)(OH2)(2)](n) and [Cu(OH2)(6)][{Cu(pydic)}(2)(mu-Cl)(2)], which results from pydicCl(2) hydrolysis. Alternatively, the new pydic(IPh)(2) (IPh = 2-iodo-phenyl) ester ligand was synthesized and reacted with anhydrous CuCl2, which yields the new binuclear complex [{Cu(pydic(IPh)(2))Cl}(2)(mu-Cl)(2)]. EPR spectroscopy of the solid compounds reveals typical axial spectra in line with the observed and DFT calculated geometries. Cyclic voltammetry and UV-vis absorption spectroscopy in solution are in line with un-dissociated complex species [Cu(pydicR(2))Cl-3](-).

The pyridine-2,6-carboxylic esters pydicR(2) with R = Me or Ph form the unprecedented mononuclear Cu-II complexes [Cu(pydicR(2))Cl-3](-) in one-pot reactions starting from pyridine-2,6-carboxychloride pydicCl(2), Cu-II chloride, and NEt3 in MeOH or PhOH solution under non-aqueous conditions. The triethylammonium salts (HNEt3)[Cu(pydicR(2))Cl-3] were isolated. The methyl derivative could be crystallized to allow a XRD structure determination. Both structures were optimized using DFT calculations in various surroundings ranging from gas phase and the non-coordinating solvent CH2Cl2 to the weakly coordinating acetone and well-coordinating solvents acetonitrile (MeCN) or dimethylformamide (DMF), while detailed calculation showed the charge distribution, dipole moments, and HOMO-LUMO gap energies changing upon solvation. According to these calculations, the ion pairs and the anionic Cu-II complexes were stable, which shows only Cu-Cl bond elongation and weakening of the charge transfer between the anionic complex and the cation as solvents become polar. Synthesis attempts in the presence of water yielded the Cu-II complexes [Cu(pydic)(OH2)(2)](n) and [Cu(OH2)(6)][{Cu(pydic)}(2)(mu-Cl)(2)], which results from pydicCl(2) hydrolysis. Alternatively, the new pydic(IPh)(2) (IPh = 2-iodo-phenyl) ester ligand was synthesized and reacted with anhydrous CuCl2, which yields the new binuclear complex [{Cu(pydic(IPh)(2))Cl}(2)(mu-Cl)(2)]. EPR spectroscopy of the solid compounds reveals typical axial spectra in line with the observed and DFT calculated geometries. Cyclic voltammetry and UV-vis absorption spectroscopy in solution are in line with un-dissociated complex species [Cu(pydicR(2))Cl-3](-).