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The reaction of the Ga+ source [Ga(PhF)2]+[Al(ORF)4]− with the neutral σ‐donor ligand dmap (4‐Me2N‐C6H4N) produces the unexpectedly large and fivefold positively charged cluster cation salt [Ga5(dmap)10]5+([Al(ORF)4]−)5. It includes a regular and planar Ga5 pentagon with strong metal–metal bonding. Additionally, the compound represents the first salt in which an ionic 1:5 packing is realized. We discuss the nature of this structure which results from the conversion of the non‐bonding 4s2 lone‐pair orbitals into fully Ga‐Ga‐bonding orbitals and the solid‐state arrangement of the ions constituting the lattice as an almost orthohexagonal AX5 lattice, possibly the aristotype of any 5:1 salt., Pentacation stories: With the aid of the strong σ‐donor 4‐dimethylaminopyridine (dmap), Ga+ ions receive enough electron density to convert their non‐bonding 4s2 orbitals into fully bonding Ga−Ga molecular orbitals and aggregate. As a result, the pentagonal pentacation [Ga5(dmap)10]5+ forms. It crystallizes with the counterion [Al(ORF)4]− in an almost orthohexagonal AX5 lattice, possibly the aristotype of any 5:1 salt.

Cylinder-shaped graphitic networks in carbon nanotubes have attracted interest from scientists in various disciplines. The chemical synthesis of their segmental molecules is being accepted as a challenging and appealing subject in the chemistry field, and their synthesis deepens our understanding of curved and conjugated arrays of hexagons. We herein report the synthesis of cylinder-shaped molecules containing non-hexagon bridges in their conjugated systems. Multiple pentagon units were embedded in the cylinder-shaped, discrete molecules, and the stereoisomerism originating from their helical carbon arrangements was revealed. Structural analyses using NMR, UV-vis absorption and single-crystal X-ray diffraction studies provided fundamental experimental information on the curved systems conjugated via pentagons. This study provides the first experimental guide for further exploration of anomalous non-hexagon arrays of graphitic carbons in cylinder shapes.

Secondary aliphatic amines add to a pole pentagon of [70]fullerene in the presence of N-fluorobenzenesulfonimide to form cyclopentadienyl-type adducts, C70(NSO2 Ph)(NR(1)R(2))4 (1), which can be converted into analogous C70 derivatives such as C70 (NHSO2 Ph)(NHTol)5 (2). Further addition reactions of either 1 or 2 take place selectively at the opposite pole pentagon of the C70 cage, thus forming curved π systems with a reduced number of π electrons, and the products include a dodecakis-adduct with a Vögtle belt motif.

Aquest mateix article està publicat a l'edició alemanya d''Angewandte Chemie' (ISSN 0044-8249, EISSN 1521-3757), 2016, vol. 128, núm. 7, p. 2420-2423. DOI http://dx.doi.org/10.1002/ange.201509057 In this work, the Bingel-Hirsch addition of diethylbromomalonate to all non-equivalent bonds of Sc3N@D3h-C78 was studied using density functional theory calculations. The regioselectivities observed computationally allowed the proposal of a set of rules, the predictive aromaticity criteria (PAC), to identify the most reactive bonds of a given endohedral metallofullerene based on a simple evaluation of the cage structure. The predictions based on the PAC are fully confirmed by both the computational and experimental exploration of the Bingel-Hirsch reaction of Sc3N@D5h-C80, thus indicating that these rules are rather general and applicable to other isolated pentagon rule endohedral metallofullerenes We are grateful to the Spanish MINECO (CTQ2014-54306-P, CTQ2014-52525-P, CTQ2014-59212-P, and JdlC contract to S.O.), the Catalan DIUE (2014SGR931, ICREA Academia 2014 Award to M.S. and XRQTC), and the FEDER fund (UNGI10-4E-801) for financial support. M.G.-B. thanks the Spanish MECD for a PhD grant (AP2010-2517) and S.O. the European Commission for CIG project (FP7-PEOPLE-2013- CIG-630978). CESCA and BSC-CNS are acknowledged. M.R.C, M.I. and L.E. thanks the NSF for generous support of this work under grant (CHE-1408865) and to the NSFPREM program (DMR-1205302). The Robert A. Welch Foundation is also gratefully acknowledged for an endowed chair to L.E. (grant AH-0033)