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Hatlike tribenzotriquinacenes 1 that bear six identical functional groups at the peripheral positions of the benzene nuclei were synthesized as starting materials for the construction of convex-concave organic networks and other three-dimensional molecular frameworks. X=NO , NH , Br, I, SnBu, Ph, CCPh.

Combining analytical and theoretical methods, we present a detailed study of a heteropolytungstate cluster encapsulated in a shell of dendritically branching surfactants, namely (C(52)H(60)NO(12))(12)[(Mn(H(2)O))(3)(SbW(9)O(33))(2)], 3. This novel surfactant-encapsulated cluster (SEC) self-assembles spontaneously from polyoxometalate-containing solutions treated with a stoichiometric amount of dendrons. Compound 3 exhibits a discrete supramolecular architecture in which a single polyoxometalate anion resides in a compact shell of dendrons. Our approach attempts to combine the catalytic activity of polyoxometalates with the steric properties of tailored dendritic surfactants into size-selective catalytic systems. The structural characterization of the SEC is based on analytical ultracentrifugation (AUC) and small-angle neutron scattering (SANS). The packing arrangement of dendrons at the cluster surface is gleaned from molecular dynamics (MD) simulations, which suggests a highly porous shell structure due to the dynamic formation of internal clefts and cavities. From analysis of the MD trajectory of 3, a theoretical neutron-scattering function is derived that is in good agreement with experimental SANS data. Force field parameters used in MD simulations are partially derived from a quantum mechanical geometry optimization of [(Zn(H(2)O))(3)(SbW(9)O(33))(2)](12)(-), 2b, at the density functional theory (DFT) level. DFT calculations are corroborated by X-ray structure analysis of Na(6)K(6)[(Zn(H(2)O))(3)(SbW(9)O(33))(2)].23H(2)O, which is isostructural with the catalytically active Mn derivative 2a. The combined use of theoretical and analytical methods aims at rapidly prototyping smart catalysts ("dendrizymes"), which are structurally related to naturally occurring metalloproteins.

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SummaryThe syntheses of tribenzotriquinacenes (TBTQ) bearing three phenylurea groupings at either the arene periphery or at the benzhydrylic bridgeheads of the rigid, convex–concave, C 3 v-symmetrical molecular framework are reported. 1H NMR data point to supramolecular aggregation of these TBTQ derivatives in low-polarity solvents.

The solid-state molecular structure of centrohexaindane (), a unique hydrocarbon comprising six benzene rings clamped to each other in three dimensions around a neopentane core, and the molecular packing in crystals of ·CHCl3 are reported. The molecular Td-symmetry and the Cartesian orientation of the six indane wings of in the solid state have been confirmed. The course and limitation of electrophilic aromatic substitution of are demonstrated for the case of nitration. Based on nitration experiments of a lower congener of , tribenzotriquinacene , the six-fold nitrofunctionalisation of has been achieved in excellent yield, giving four constitutional isomers, two nonsymmetrical ( and ) and two C3-symmetrical ones ( and ), all of which contain one single nitro group in each of the six benzene rings. The relative yields of the four isomers (∼3 : 1 : 1 : 3) point to a random electrophilic attack of the electrophiles at the twelve formally equivalent outer positions of the aromatic periphery of , suggesting electronic independence of its six aromatic π-electron systems. In turn, the pronounced conformational rigidity of the centrohexacyclic framework of enables the unequivocal structural identification of the isomeric hexanitrocentrohexaindanes by (1)H NMR spectroscopy.

Hütchenförmige Tribenzotriquinacene 1 mit sechs identischen funktionellen Gruppen an den peripheren Positionen der Benzolkerne wurden als Ausgangsverbindungen für den Aufbau konvex‐konkaver organischer Netze und anderer dreidimensionaler Molekülgerüste synthetisiert. X = NO2, NH2, Br, I, SnBu, Ph, CCPh.

The syntheses of a novel tetraindan 6, containing two contiguous quaternary central carbon atoms, and of a number of other derivatives of the (unknown) "irregular" centrotriindan 5, is reported. Two-fold bridgehead benzylation of the C2-symmetrical diindandione 7 followed by reduction leads to the dibenzyldiindandiols 11, which undergo 2-fold acid-catalyzed cyclodehydration (H3POr/ chlorobenzene) in moderate yield (22 5% ) to 6. In contrast, use of xylene as the solvent gives rise to a Wagner-Meerwein rearrangement along with a single cyclodehydration step producing benzylidenetriindan 14 in good yield (70 5% 1. Monobenzyldiindandiols 10 incorporate a solvent molecule upon cyclodehydration in p-xylene to give triindan 12, whereas use of chlorobenzene yields complex mixtures of triindene 13 and its oligomers. These results shed some light on the relatively high strain of the tetraquinane skeleton of 6 and, in particular, on the reactivity of bridgehead [A(9b,lO)ldiindenes, in line with previous results. An independent attempt to generate 6 from 2,2'-biindanyltetrol 16 gave the dibenzodioxatetraquinane 17 in low yield.In 1981, Gund and Gund2 published a classification scheme of complex polycyclic organic ring systems bearing a carbon atom which is shared by all of the rings. Among these centropolycyclanes,2 centropolyquinunes, Le., those congeners bearing mutually fused cyclopentane units, have been of particular interest because of their relation to naturally occurring314 and non-natural m o d e F systems and because of the favorable steric fit of centrically fused five-membered rings.Centropolyindans, the benzoannelated analogues of centropolyquinanes, obey the same classification scheme.8 During the past decade, all higher members of the family of "regular" centropolyindans have been synthesized in our laboratory,"ll including various centrotriindans and centrotetraindans (e.g., l,lonJld and, respectively, 21°bJld and 319 and the highest possible congeners, centropentaindan12 and ~entr0hexaindan.l~ (2) Gund, P.; Gund, T. M.