N-propanol Molecules Research Articles

Solubility and thermodynamic aspects of etonogestrel in several aqueous co-solvent solutions

The current work was devoted to the investigation on equilibrium solubility, Hansen solubility parameter, solvation performance and dissolution thermodynamics of etonogestrel in binary aqueous blends of the cosolvents {n-propanol, N,N-dimethylformamide (DMF), ethanol or isopropanol} by experimentation and several mathematical relationships. The solubility determination was conducted under atmospheric pressure (101.2 kPa) from 278.15 to 323.15 K through the common shake-flask method. The maxima of etonogestrel solubility expressed in mole fraction scale at 323.2 K were observed as 8.713 × 10−3 for ethanol, 16.81 × 10−3 for n-propanol, 19.52 × 10−3 for isopropanol and 121.4 × 10−3 for DMF; while the minimum was 0.01477 × 10−3 for pure water at 278.15 K. The solubility performance of etonogestrel was deeply considered by means of Hansen solubility parameter concept. The obtained equilibrium solubility was computationally expressed by modified Jouyban–Acree–van’t Hoff model, mixture response surface (MRS) model, modified Wilson model and Jouyban–Acree model with the relative average deviations of no higher than 7.12%. The relative prominence of solvent–solvent and solute–solvent molecule interactions on etonogestrel solubility variation specified the dipolarity-polarizability and solubility parameter of solution descriptors that was studied in terms of the linear solvation energy relationships. The extended Hildebrand solubility approach was used to inspect the solubility data at 298.15 K acquiring the correlation coefficient of >0.9999. The quantitative investigation on preferential solvation of etonogestrel by solvent species in different solutions was made by the inverse Kirkwood–Buff integrals technique in terms of numerous solution properties. Positive preferential solvation parameters for cosolvents of isopropanol, DMF, ethanol and n-propanol in aqueous solutions with cosolvent-rich and intermediate scopes suggested the preferential solvation of etonogestrel by the cosolvents (isopropanol/DMF/ethanol/n-propanol). It was assumed that etonogestrel acted as a Lewis acid in these composition ranges with the isopropanol/DMF/ethanol/n-propanol molecules. Thermodynamic analysis of dissolution properties and enthalpy–entropy compensation demonstrated an entropy-driven mechanism and endothermic process for etonogestrel dissolved in different blended solvents.

Maraviroc in aqueous co-solvent solutions of n-propanol, ethanol, dimethyl sulfoxide and N,N-dimethylformamide: Solubility determination, preferential solvation and solvent effect analysis

The liquid–solid equilibrium and solubility of maraviroc in co-solvent mixtures of n-propanol, ethanol, dimethyl sulfoxide (DMSO) and N,N-dimethylformamide (DMF) plus water was obtained via the saturation shake-flask technique between 278.15 K and 323.15 K under 101.2 kPa. For the four aqueous co-solvent mixtures investigated, the mole fraction solubility of maraviroc increased with the increase in the temperature and mass fraction of n-propanol, ethanol, DMSO and DMF. The maximum solubility values of maraviroc were observed in the neat co-solvents. The dependence of the maraviroc solubility on the solvent composition and temperature was mathematically correlated by means of the Jouyban-Acree model. The obtained values of relative average deviation (RAD) and root-mean-square deviation (RMSD) were no more than 4.16 × 10−2 and 49.13 × 10−6, respectively. KAT-LSER model was implemented to get quantitative information about solvent effect on the variation of solubility data. The variation in the maraviroc solubility was dependent upon the hydrogen-bond donation and cavity term in n-propanol + water and ethanol + water mixtures; and the cavity term was the dominant term in the (DMSO + water) and (DMF + water) mixtures. Quantitative study was made for the local mole fraction of ethanol (n-propanol, DMSO and DMF) and water around the maraviroc by the Inverse Kirkwood–Buff integrals method applied to the solubility data determined. Maraviroc was preferentially solvated by ethanol or n-propanol for the aqueous co-solvent mixtures of ethanol or n-propanol in intermediate and ethanol/n-propanol-rich compositions. It was conjecturable that maraviroc could act mainly as a Lewis acid in front to the ethanol or n-propanol molecules. However in the {n-propanol (1) + water (2)} mixture with compositions 0 < x1 < 0.20, ethanol (1) + water (2) mixture with compositions 0 < x1 < 0.25 and DMF/DMSO mixtures within entire compositions, maraviroc was preferentially solvated neither by co-solvent (1) nor by water.

Syntheses, Crystal Structures and Thermal Behaviors of Two Supramolecular Salamo-Type Cobalt(II) and Zinc(II) Complexes

This paper reports the syntheses of two new complexes, [Co(L1)(H2O)2] (1) and [{Zn(L2)(μ-OAc)Zn(n-PrOH)}2] (2), from asymmetric halogen-substituted Salamo-type ligands H2L1 and H3L2, respectively. Investigation of the crystal structure of complex 1 reveals that the complex includes one Co(II) ion, one (L1)2− unit and two coordinated water molecules. Complex 1 shows slightly distorted octahedral coordination geometry, forming an infinite 2D supramolecular structure by intermolecular hydrogen bond and π–π stacking interactions. Complex 2 contains four Zn(II)ions, two completely deprotonated (L2)3− moieties, two coordinated μ-OAc− ions and n-propanol molecules. The Zn(II) ions in complex 2 display slightly distorted trigonal bipyramidal or square pyramidal geometries.

Cβ-H stretching vibration as a new probe for conformation of n-propanol in gaseous and liquid states.

The development of potential probes to identify molecular conformation is essential in organic and biological chemistry. In this work, we investigated a site-specific C-H stretching vibration as a conformational probe for a model compound, 1,1,3,3,3-deuterated n-propanol (CD3CH2CD2OH), using stimulated photoacoustic Raman spectroscopy in the gas phase and conventional spontaneous Raman spectroscopy in the liquid state. Along with quantum chemistry calculations, the experiment shows that the CH2 symmetric stretching mode at the β-carbon position is very sensitive to the conformational structure of n-propanol and can serve as a new probe for all five of its conformers. Compared with the O-H stretching vibration, a well-established conformational sensor for n-propanol, the Cβ-H stretching vibration presented here shows better conformational resolution in the liquid state. Furthermore, using this probe, we investigated the conformational preference of n-propanol in pure liquid and in dilute water solution. It is revealed that in pure liquid, n-propanol molecules prefer the trans-OH conformation, and in dilute water solution, this preference is enhanced, indicating that the water molecules play a role of further stabilizing the trans-OH n-propanol conformers. This leads to conformational evolution that n-propanol molecules with gauche-OH structure are transferred to the trans-OH structure upon diluting with water. These results not only provide important information on structures of n-propanol in different environments, but also demonstrate the potential of the C-H stretching vibration as a new tool for conformational analysis. This is especially important when considering that hydrocarbon chains are structural units in organic and biological molecules.

A novel trinuclear cobalt(II) complex derived from an asymmetric Salamo-type N2O3 bisoxime chelate ligand: Synthesis, structure and optical properties

A novel trinuclear Co(II) complex, {[CoL(PrOH)]2Co(H2O)}·PrOH, has been synthesized with 6-ethoxy-6′-hydroxy-2,2′-[ethylenedioxybis(nitrilomethylidyne)]diphenol (H3L), and characterized by elemental analyses, FT-IR, UV–Vis, molar conductance and X-ray crystallographic analysis. Two n-propanol molecules and one water molecule coordinate to three Co(II) ions and four μ-phenoxo oxygen atoms from two [CoL(CH3CH2CH2OH)] units also coordinating to Co(II) ion. All the penta-coordinated Co(II) ions of the Co(II) complex have a slightly distorted trigonal bipyramidal coordinated polyhedron. Meanwhile, the μ-phenoxo bridges play important roles in assembling Co(II) ions and L3− units, which is different from the normal trinuclear Co(II) complexes with the Salamo-type ligands reported early.

Synthesis, crystal structure and spectral properties of a supramolecular trinuclear nickel(II) complex with 5-methoxy-4′-bromo-2,2′-[ethylenedioxybis(nitrilomethylidyne)]diphenol

A novel trinuclear Ni(II) complex [{NiL(n-PrOH)(μ-OAc)}2Ni]·n-PrOH·H2O with an asymmetric Salamo-type ligand, 5-methoxy-4′-bromo-2,2′-[ethylenedioxybis(nitrilomethylidyne)]diphenol (H2L), has been synthesized and characterized by elemental analyses, IR, UV/Vis and fluorescence spectra and molar conductance measurement. The crystal structure of the Ni(II) complex has been determined by single-crystal X-ray diffraction. Two acetate groups coordinating to three Ni(II) ions through NiOCONi bridges and four μ-phenoxo oxygen atoms from two [NiL(n-PrOH)] units also coordinating to Ni(II) ions. In the Ni(II) complex, two n-propanol molecules are coordinated to the two terminal Ni(II) ions having slightly distorted octahedral coordination geometries and form a trinuclear structure, There are also one non-coordinated n-propanol and one non-coordinated water molecule. In the crystal structure, the Ni(II) complex is linked by intermolecular hydrogen bonds into an infinite 1D supramolecular chain-like structure.

Synthesis, structural characterization and solvent effect of copper(II) complexes with a variational multidentate Salen-type ligand with bisoxime groups

Four new solvent-induced Cu(II) complexes with the chemical formulae [{Cu(HL)(CH 3OH)} 2Cu] · CH 3OH ( 1), [{(Cu(HL)) 2(CH 3CH 2OH) 2}Cu] ( 2), [{CuL(H 2O)} 2Cu 2] · 2CH 3CH 2CH 2OH ( 3) and [{(Cu(HL)) 2(CH 3CH 2CH 2CH 2OH) 2}Cu] ( 4), where H 4L = 6,6′-dihydroxy-2,2′-[ethylenediyldioxybis(nitrilomethylidyne)]diphenol, have been synthesized and characterized by elemental analyses, 1H NMR, FT-IR, UV–Vis spectra, TG-DTA, molar conductances and X-ray crystallography. Complexes 1, 2 and 4 have an elongated square-pyramidal geometry with an unusually long bond from the penta-coordinated Cu(II) centres to the oxygen atoms of the apically coordinated solvent (methanol, ethanol or n-butanol) molecules for the terminal Cu(II) ions, and a square planar geometry distorted tetrahedrally for the central Cu(II) ion. In complex 3, the terminal Cu(II) ions have trigonal bipyramidal coordination geometries constituted by equatorial O 2N donor sites, with one oxygen atom from one of the coordinated water molecules and one nitrogen atom from a completely deprotonated L 4− ligand unit in the axial positions, and the central Cu(II) ions are in slightly tetrahedrally distorted square planar geometries constituted by four phenoxo oxygen donors from two completely deprotonated L 4− ligand units, and these form a tetrametal Cu–O–Cu–O–Cu–O–Cu–O eight-membered ring. These four complexes exhibit strong hydrogen bonding interactions in the solid state. Moreover, co-crystallizing n-propanol molecules link two other adjacent complex molecules into a self-assembled infinite 2D supramolecular structure via the intermolecular hydrogen bonds in complex 3.

Two stereoisomeric 3 I,2 II-anhydro-α-cyclodextrins: a molecular dynamics and crystallographic study

Regioselective epoxide ring opening of 2 I,3 I-(2 I S)-anhydro-α-cyclodextrin ( 1) through intramolecular attack of hydroxyl groups of neighboring glucose rings occurs in diequatorial fashion to yield 3 I,2 II-anhydro-α-cyclodextrin ( 3) with a rigid glucopyranose–dioxane–glucopyranose tricyclic ring system, the usual diaxial opening and the gluco/altro-configurated stereoisomer 2 cannot be detected. Molecular dynamic simulations in water were used to analyze the conformations of 1– 3 and the stereochemical implications of this reaction. Due to the contracted 2,3-OH side of the torus, 3 features an inverted conicity compared to the parent α-cyclodextrin. A crystallographic study on the bis- 3·3 n-PrOH nonahydrate not only displays little variations between the solid-state and solution geometries of 3, but also provides a molecular picture of a unique inclusion complex in which three n-propanol molecules are distributed in the cavity of a dimeric unit of 3 (monoclinic, space group P2 1, a=14.257(1), b=22.623(2), c=16.644(1) Å, β=104.82(1)°, all 19278 reflections with I>2 σ( I) yield R( F)=0.1017).

Effect of interlayer spacing on intercalation of CdS in clays

The effect of laponite clay interlayer space on intercalation of CdS has been investigated. Results indicate that the degree of “openness” of the interlayer space of the laponite film determines whether the intercalation of CdS in laponite film can occur. In these systems, solvents play the dominant role in opening the interlayer space. As methanol molecules cannot open the interlayer space sufficiently to allow S 2− anions to penetrate into the clay, CdS is formed only on the external surface of the laponite-methanol systems. However, ethanol and n-propanol molecules expand the layers sufficiently for CdS to form inside the interlayers. The minimum basal d-spacing of an intercalated clay can be estimated from summation of the thickness of the tetrahedra-octahedra-tetrahedra sheet of clays and the diameters of guest molecules, if a monolayer of guest molecules is intercalated into the clay.

Study of the electrooxidation of n-propanol on an Au electrode in basic medium

This paper describes the oxidation mechanism of n-propanol on polycrystalline gold electrodes in basic solutions. The oxidation takes place after adsorption of n-propanol molecules on the AuOH coverage and continues only up to the formation of n-propanol under the working conditions used. A coherent explanation for every experimental fact has been found. This was accomplished by using a modified Temkin isotherm to describe the AuOH coverage and non-activated adsorption for the n-propanol molecules on the AuOH coverage. Further steps give rise to n-propanoic acid as a final product.

Studies of isotropic phosphatidyl choline- n-propanol-water systems

Formation of isotropic solutions of egg phosphatidyl choline in methanol—water, ethanol—water and n-propanol-water systems has been studied, and the phase diagrams (in part) of these ternary systems determined. The concentrations of methanol, ethanol and n-propanol in aqueous solvents producing break-up of large phosphatidyl choline aggregates are, respectively 72.50%, 46.33% and 17.51% (w/w) at infinite dilution of phosphatide at 23°C. Isotropic solutions of phosphatidyl choline in 20–25% n-propanol—water solvents contain micelles of 12–14 phosphatide monomers at concentrations of phosphatide of 0.02–0.04 g/cm 3 solution, as determined by light-scattering. Osmotic pressure measurements on solutions containing 0–0.003 g phosphatide/cm 3 indicate that smaller aggregates or monomers are the predominant species in solution; no sharp critical micelle concentration is observed. Light-scattering and viscosity measurements on these solutions, indicate a strong interaction between phosphatide and n-propanol molecules, and a solvation of about 12–20 moles propanol per mole phosphatide is calculated from the viscosity data. A qualitative model is described which may account for the properties of aqueous alcoholic solutions of phosphatidyl choline.