Molecules In Crystalline State Research Articles

High-Performance Small Molecule/Polymer Ternary Organic Solar Cells Based on a Layer-By-Layer Process.

PSS), and then the mixed solution of polymer and fullerene derivative was spin-coated on top of a small molecule layer. In this method, the small molecules in crystalline state were effectively mixed in the active layer. Without further optimization of the morphology of the ternary blend, a high power conversion efficiency (PCE) of 8.76% was obtained with large short-circuit current density (Jsc) (17.24 mA cm(-2)) and fill factor (FF) (0.696). The high PCE resulted from not only enhanced light harvesting but also more balanced charge transport by incorporating small molecules.

Structural characterization of β-2′-pyridylaminocrotonoyl-2-pyridylamide by ESI-MS, NMR, single crystal X-ray analysis and ab initio methods

In contradiction with earlier reports 1H, 13C and 15N NMR spectra show that β-2′-pyridylaminocrotonoyl-2-pyridylamide is the only form present in chloroform solution. According to the X-ray data the same tautomer exists also in the crystal state. The studied amide has a dimeric form where the monomer molecules are held together by two intermolecular hydrogen bonds. The NMR spectral data show that there is also an intramolecular hydrogen bond in each monomer subunit. The dilution experiments and variable-temperature 1H NMR runs show that β-2′-pyridylaminocrotonoyl-2-pyridylamide tends to form the dimers also in chloroform solution at higher concentrations. The ESI-TOF MS measurements at different concentrations confirm that there is a dimerization process taking place in solution. The calculated energetic effect of dimerization of β-2′-pyridylaminocrotonoyl-2-pyridylamide in vacuum is equal to −34 kJ/mol (exothermic process). X-ray analysis shows that the molecule in crystalline state is not planar. The ab initio RHF/6-31G** calculations approximate well the X-ray determined molecular geometry of β-2′-pyridylaminocrotonoyl-2-pyridyl-amide.

Extended structures controlled by intramolecular and intermolecular hydrogen bonding: a case study with pyridine-2,6-dicarboxamide, 1,3-benzenedicarboxamide and N,N′-dimethyl-2,6-pyridinedicarboxamide

The small organic molecule pyridine-2,6-dicarboxamide, although known in the literature for some time, exhibits interesting and previously unexplored intermolecular and intramolecular hydrogen bonding both in solid state and in solution. With the aid of X-ray crystallography and variable-temperature NMR spectroscopy, we here demonstrate the presence of a very strong hydrogen bonding network for this molecule both in condensed state and solution. Furthermore, a novel extended hydrogen bonding graph-set has been derived for this molecule in crystalline state. Comparison of pyridine-2,6-dicarboxamide with 1,3-benzenedicarboxamide, where the intramolecular hydrogen bonding to the pyridine ring in the former has been removed, yields a different intermolecular hydrogen bonded structure in the solid state. A new graph-set has been determined for the extended structure of 1,3-benzenedicarboxamide in the solid state. In solution, 1,3-benzenedicarboxamide is shown to maintain a hydrogen bonding pattern that is weaker than that observed with pyridine-2,6-dicarboxamide. Replacement of one hydrogen on each carboxamide nitrogen of pyridine-2,6-dicarboxamide by a methyl group also alters the extended structure to a significant extent. In N,N′-dimethyl-2,6-pyridinedicarboxamide, the three-dimensional hydrogen bonding pattern observed with pyridine-2,6-dicarboxamide all but collapses to one-dimensional chains.

Radiochemische und elektrochemische untersuchung der adsorption von cytochrom c an der phasengrenze elektrolyt/quecksilber

The surface area of an adsorbed cytochrome-c molecule was calculated both from the radiochemically determined surface concentration and from the adsorption kinetics. The value thus obtained is 2000±200 Å 2. This accordance shows that the Koryta equation holds for the adsorption kinetics of proteins. The comparison with the cross-section of the molecule in crystalline state allows us to conclude that cytochrome c is unfolded at the electrode. While at low concentrations the molecules are strongly adsorbed, at high concentrations an exchange of adsorbed molecules with molecules in the bulk occurs. The mechanism of charge transfer is proposed to be a superposition of electron transport through adsorbed molecules and exchange of already reduced molecules.

Method for Determining Conformations of Polymer Molecules in Crystalline State from Fiber Identity Distances

A mathematical method is presented for determining helical conformations, or more precisely, positions of atoms relative to the helical axis and internal rotational angles about skeletal bonds, of a polymer molecule in crystalline state, straightforwardly from bond lengths and bond angles of the chain skeleton, and the translational distance along the helical axis and the rotational angle about the axis per one repeating unit. The treatment is confined to one-, two-, and three-atom helices, i.e., those whose stereochemical and conformational repeating units are composed of one, two, and three consecutive skeletal atoms, respectively. A nonhelical conformation also is included as a special helix. The method is illustrated by the two examples, poly-p-fluorostyrene and polypeptides, for which it was originally devised.

Convex-Core Model of Molecules in Crystalline State. II

The convex-core model of molecules, which has been effective for discussing thermodynamic properties of polyatomic gases, is applied to the crystals of benzene and ethylene as a continuation of a previous article of the same title, in which crystals of methane, carbon dioxide, and nitrogen were treated. By use of model parameters determined from the second virial coefficients, cohesive energies and lattice constants are calculated. When we neglect zero-point energies, potential non-additivities, and electric multipole interactions, then the calculated cohesive energies are close to the observed values for benzene and 16%. higher for ethylene. The calculated lattice constants agree well with observed ones in both cases. Stability of the benzene crystal is discussed, but the conclusions are not as definite as in the case of carbon dioxide.

ポリオキシメチレン (Deirin) の構造化学的研究

Structural studies of polyoxymethylene (POM) have been undertaken by use of the infrared and X-ray measurements from the point of view of the simplicity of the chemical structure and of the interesting helical configuration of the molecule in crystalline state. In this preliminary report the method of preparation of thin films of this polymer suitable for the infrared measurements is described. The film samples (oriented or non-oriented) of required thickness (5-10μ) can be easily prepared by this method. The polarized infrared spectra of POM in the 3500-400cm-1 region were reproduced.

Convex-Core Model of Molecules in Crystalline State

The convex-core model of molecules, which has been effective for discussing thermodynamic properties of polyatomic gases, is applied to the crystals of benzene and ethylene as a continuation of a previous article of the same title, in which crystals of methane, carbon dioxide, and nitrogen were treated. By use of model parameters determined from the second virial coefficients, cohesive energies and lattice constants are calculated. When we neglect zero-point energies, potential non-additivities, and electric multipole interactions, then the calculated cohesive energies are close to the observed values for benzene and 16%. higher for ethylene. The calculated lattice constants agree well with observed ones in both cases. Stability of the benzene crystal is discussed, but the conclusions are not as definite as in the case of carbon dioxide.