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Preface to Advances in Artificial Life, Evolutionary Computation, and Systems Chemistry 11th Italian Workshop, WIVACE 2016, Fisciano, Italy, October 4-6, 2016, Revised Selected Papers
No full textLipid aggregates inducing symmetry breaking in prebiotic polymerizations
Full text linkIt is a long-standing and still open problem to determine the origin of biomolecular
homochirality, and many scenarios have been suggested. Amphiphilic molecules are renowned for
their capability to reorganize themselves in a variety of different morphologies and topologies, and
for their capability to partition chemicals in well defined domains. Here a possible role for amphiphilic
molecules inducing symmetry breaking is suggested in the framework of the research on
origin of life
CURVIS: a program to study and analyze crystallographic structures and phase transitions
No full textThe visualization of scientific data is, nowadays, of extreme importance. Phase transitions, the topology of a crystallographic system, the electron density
distribution inside a lattice or the changes in crystal structure during phase transitions cannot be fully investigated without the help of proper visualization.
The program CURVIS (downloadable free of charge upon request) was developed as a tool for investigating crystal structures and occurring transitions.
In this tool, some features are implemented to analyse, display and manage the three-dimensional structure of crystals and single molecules. More importantly,
CURVIS can generate and handle hyperbolic surfaces in three dimensions, and provide specific routines to perform calculations of curvature and energy of such surfaces. The most important features are (i) file format conversion (with
assignment of the atom types and atomic charges), (ii) surface calculation and (iii) curvature and surface-energy analysis
Monte Carlo simulations of vesicles and fluid membranes transformations
Full text linkThe appearance of compartmentalization is recognized as a key step in biogenesis. The
study of the dynamical behaviour of amphiphilic close membranes at equilibrium or under some
external stress (osmotic pressure or dehydration process) can be useful in order to better elucidate
the role of vesicles in the origin of life and to get insight into the molecular and membrane properties
that bring to a spontaneous vesicle division. A Monte Carlo approach to simulate the evolution of
close membranes under an external stress will be presented. This approach is mainly based on the
accepted surface energy model introduced by Helfrich (1973) and Seifert (1997a). Some preliminary
results will be also illustrated and possible developments and limits of this method discussed
Mono-, Di-, and Polymeric Pyridinoylhydrazone ZnIIComplexes: Structure and Photoluminescent Properties
No full textA series of zinc complexes with tridentate pyridinoylhydrazone ligands bearing two different end groups and coordinated pyridine molecules were synthesized and characterized. Crystal structures with mono-, di-, and polymeric arrangements were obtained, depending on the position of the pyridinoyl nitrogen atom. Direct involvement of the pyridinoyl moiety in the coordination to the metal was observed when the nitrogen was in the ortho or meta position. The meta derivatives led to 1D polymers with the same coordination environment, regardless of the bulkiness of the end group. In this case, unprecedented solid-state photoluminescence quantum yields were recorded. In the ortho ligands, the further bidentate N,N site involving the pyridinoyl nitrogen atom was able to coordinate a further zinc acetate unit. Molecular and periodic calculations were performed within density functional theory (DFT) to rationalize the photophysical behavior. Excellent agreement between the theoretical and experimental absorptions was observed. The HOMOs and LUMOs of the complexes were investigated both in the solid state and in solution
From cadmium(II)-aroylhydrazone complexes to metallopolymers with enhanced photoluminescence. A structural and DFT study
No full textReaction of cadmium(II) acetate and donor-acceptor conjugated O,N,O ligands led to complexes with coordinated pyridine and to polymeric materials by grafting onto poly(4-vinylpyridine). All the synthesized compounds exhibited luminescent properties. Two ligands series with and without a bulky end group produced molecular structures with a dinuclear arrangement. Structural and photophysical properties were systematically explored and compared to previously reported zinc complexes. Benzothiazole containing ligands revealed a new coordination mode with respect to zinc. Quantitative emission measurements were performed on solid samples of complexes and polymers. Differences of photoluminescence quantum yields in molecular complexes and grafted polymers were revealed. Experimental absorption and emission data were explained by theoretical calculations on crystalline and insulated models
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