1. Contribution from the Laboratory of Macromolecular Physical Chemistry, UMR-7568 CNRS-INPL, ENSIC, BP 451, 54001 Nancy, France, Department of Organic Chemistry, ICMA, CSIC-University of Zaragoza, E-50009 Zaragoza, Spain, and Laboratory of Crystallography and Modeling of Mineral and Biological Materials, ESA-7036, University Henri Poincaré of Nancy, BP 236, 54509 Vandoeuvre, France