Showing papers by "Mercedes Camalli published in 2011"
TL;DR: In this article, the standard version of Sir2008 is modified to include several new tools, which are expected to make the phasing process more straightforward, and particular emphasis is given to a new procedure for the determination of the space groups, aiming at reducing in the practice the perverse effects of the dynamical scattering and to the simulated annealing algorithm.
Abstract: The crystal structure solution of small-medium size molecules via single crystal X-ray data is almost a routine process. When single crystals of sufficient dimensions are not available, electron diffraction is a useful alternative: the structure solution however may still be a challenge. We have modified the standard version of Sir2008 to include several new tools, which are expected to make the phasing process more straightforward. Additional work is in progress: in Sir2011, the heir of Sir2008, particular emphasis will be given to a new procedure for the determination of the space groups, to a new approach (BEA) aiming at reducing in the practice the perverse effects of the dynamical scattering and to the simulated annealing algorithm, as a phasing tool particularly useful in case of organic structures, when scarce or poor experimental data are available. (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
5 citations
TL;DR: The solid-state assembly of two calixcyclitol derivatives bearing two or one rings (compounds 1 or 2, respectively) oxyfunctionalized with oxetane and hydroxyl functional groups has been structurally studied by X-ray crystallography as discussed by the authors.
Abstract: The solid-state assembly of two calixcyclitol derivatives bearing two or one rings (compounds 1 or 2, respectively) oxyfunctionalized with oxetane and hydroxyl functional groups has been structurally studied by X-ray crystallography. Calixcyclitol 1 can assemble to give a H-bonded layered (crystals 1A) or double-columnar (crystals 1B) structure with alternating polar and lipophilic zones. Calixcyclitol 2 gives a double-helical arrangement through the intermediacy of H2O and MeOH molecules.
5 citations