Chemical bonding in supermolecular flowers

We report here a systematic study on the ability of molecular cages to bind (transition) metals. Starting from the superferrocenophane we investigate the incorporation of first-row transition metal (Sc-Zn) and alkaline-earth metal (Mg, Ca) double cations into these supermetallocenophane (super[5]phane) cages, and compare them with the corresponding metallocenes (Inorg. Chim. Acta, 2007, 360, 179). Moreover, we also investigate the binding of neutral and double-cationic metals inside supermetallocyclophane (super[6]phane) cages. The heterolytic and homolytic associations show preferences for different metals, and new metal-containing cages are proposed that should be viable candidates for synthesis The following organizations are thanked for financial support: the Ministerio de Ciencia e Innovacion (MICINN, project number CTQ2011-25086/BQU), and the DIUE of the Generalitat de Catalunya (project number 2009SGR528). Financial support from MICINN (Ministry of Science and Innovation, Spain) and the FEDER fund (European Fund for Regional Development) was provided by grant UNGI08-4E-003. The authors are grateful to the Research Executive Agency of the European Research Council for financial support through the PIRSES-GA-2009-247671 project of the FP7-PEOPLE-2009-IRSES program. MPJ acknowledges support from the Ministerio de Ciencia e Innovacion (project JCI-2009-05953) and the Academy of Finland (project 136079). This work was supported in Guanajuato by Conacyt (Grant 57892); ACC thanks Conacyt for the Master fellowship