Syntheses, crystal structures, ab initio density functional theory computations, and photophysical properties of 1,6-di-, 1,2,5,6-tetra-, and 1,3,5,7,9-pentaethynyl-substituted corannulenes (classes 3, 4, and 5, respectively) are reported. Classes 3 and 4 were prepared from the corresponding corannulenyl bromides and terminal alkynes in excellent yields (nine examples, with yields of 57-92%) using the Sonogarshira reaction. Class 5 was prepared from 1,3,5,7,9-pentacholorocorannulene and trimethylalkynylstannanes using a modification of Nolan's procedure (8 examples, with yields of 45-93%). The molecular packing in crystals of 1,6-diphenylethynyl-2,5-dimethylcorannulene (3-Ph2) displays a polar columnar structure with all of the molecule bowls oriented in the same direction. Similarly, 1,2,5,6-tetrakis(3,5-dimethylphenylethynyl)corannulene [4-Ar(c)5] and 1,3,5,7,9-pentakis(3,5-dimethylphenylethynyl)corannulene [5-Ar(c)5] form columnar structures, but the bowls are oriented in opposing directions. Additionally, the number of attached alkynyl arms is correlated with an increase in bowl depth of the corrannulene nucleus. Most of the aryl derivatives displayed high-quantum-efficiency solution luminescence and variable emission wavelengths that were dependent on the nature of the substitution.

The synthesis and characterization of two direct platinum (1 and 6a/b) and three ethynyl-platinum corannulene derivatives (2, 8 and 9), bearing 2, 4, or 5 square planar platinum centers, are presented. The structure of the bowl bearing substituents remains comparable to corannulene and the dynamic behavior of the bowl inversion as assessed by VT NMR supports a persistent bowl structure in solution. These platinum-corannulenes are well-structured tectons for the future assembly of coordination Platonic polyhedra.

This work defines a maximally labeled isomer problem in the context of 1,3,5,7,9-pentasubstituted corannulenes and explores two new synthetic strategies for the construction of key C-C bonds in the corannulene nucleus: a) a Diels-Alder cycloaddition of thiophene dioxide and acenaphthene fragments; b) a manganese-mediated reductive coupling of benzylic halides, which tolerates carboxy ester functionality. It advances the area of curved aromatics based on corannulene by setting a new family of targets for chemical synthesis and providing additional general synthetic tools.

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Other polycyclic compounds Q 1150 Multiethynyl Corannulenes: Synthesis, Structure, and Properties. -Title compounds such as (III), (V), or (VIII) are prepared either by Sonogashira coupling or via a modified Nolan protocol. In combination with high fluorescence quantum yields, the products have potential for the development of photoactive and/or liquid-crystalline materials. -(WU, Y.-T.; BANDERA, D.; MAAG, R.; LINDEN, A.; BALDRIDGE*, K. K.; SIEGEL, J. S.; J.