Pagodane is an

organic compound Some chemical authorities define an organic compound as a chemical compound that contains a carbon–hydrogen or carbon–carbon bond; others consider an organic compound to be any chemical compound that contains carbon. For example, carbon-co ...

with formula whose

carbon Carbon () is a chemical element; it has chemical symbol, symbol C and atomic number 6. It is nonmetallic and tetravalence, tetravalent—meaning that its atoms are able to form up to four covalent bonds due to its valence shell exhibiting 4 ...

skeleton was said to resemble a

pagoda A pagoda is a tiered tower with multiple eaves common to Thailand, Cambodia, Nepal, India, China, Japan, Korea, Myanmar, Vietnam, and other parts of Asia. Most pagodas were built to have a religious function, most often Buddhist, but some ...

, hence the name. It is a polycyclic

hydrocarbon In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons are examples of group 14 hydrides. Hydrocarbons are generally colourless and Hydrophobe, hydrophobic; their odor is usually fain ...

whose molecule has the ''D''_2''h'' point symmetry group. The compound is a highly crystalline solid that melts at 243 °C, is barely soluble in most organic solvents and moderately soluble in

benzene Benzene is an Organic compound, organic chemical compound with the Chemical formula#Molecular formula, molecular formula C6H6. The benzene molecule is composed of six carbon atoms joined in a planar hexagonal Ring (chemistry), ring with one hyd ...

and

chloroform Chloroform, or trichloromethane (often abbreviated as TCM), is an organochloride with the formula and a common solvent. It is a volatile, colorless, sweet-smelling, dense liquid produced on a large scale as a precursor to refrigerants and po ...

. It sublimes at low pressure. The name pagodane is used more generally for any member of a family of compounds whose molecular skeletons have the same 16-carbon central cage as the basic compound. Each member can be seen as the result of connecting eight atoms of this cage in pairs by four

alkane In organic chemistry, an alkane, or paraffin (a historical trivial name that also has other meanings), is an acyclic saturated hydrocarbon. In other words, an alkane consists of hydrogen and carbon atoms arranged in a tree structure in whi ...

chains. The general member is denoted 'm''.''n''.''p''.''q''agodane where ''m'', ''n'', ''p'' and ''q'' are the number of carbons of those four chains. The general formula is then where ''s''= ''m''+''n''+''p''+''q''. In particular, the basic compound has those carbons connected by four

methylene bridge In chemistry, a methylene bridge is part of a molecule with formula . The carbon atom is connected by single bonds to two other distinct atoms in the rest of the molecule. A methylene bridge is often called a methylene group or simply methylene, ...

s (''m''=''n''=''p''=''q''=1), and its name within that family is therefore .1.1.1agodane.

Synthesis and structure

The compound was first synthesized by Horst Prinzbach and his associates in 1987, by a 14-step sequence starting from isodrin. In the process they also synthesized .2.1.1agodane and several derivatives. Prinzbach remarked that "the obvious need for he short name 'pagodane'can be readily understood in view of the von Baeyer/

IUPAC The International Union of Pure and Applied Chemistry (IUPAC ) is an international federation of National Adhering Organizations working for the advancement of the chemical sciences, especially by developing nomenclature and terminology. It is ...

and

Chemical Abstracts Chemical Abstracts Service (CAS) is a division of the American Chemical Society. It is a source of chemical information and is located in Columbus, Ohio, United States. Print periodicals ''Chemical Abstracts'' is a periodical index that provid ...

nomenclature", undecacyclo .9.0.0^1,5.0^2,12.0^2,18.0^3,7.0^6,10.0^8,12.0^11,15.0^13,17.0^16,20cosane. In carbon skeleton of pagodane, there can be distinguished many

propellane In organic chemistry, propellane is any member of a class of polycyclic compound, polycyclic hydrocarbons, whose carbon skeleton consists of three rings of carbon atoms sharing a common carbon–carbon bond, carbon–carbon covalent bond. The co ...

-type fragments. The overall synthesis can be summarized as follows: The scheme depicted here may be shortened to 14 one-pot operations with 24% overall yield. Yet, this variation requires the use of tetrachlorothiophenedioxide instead of tetrachloro-dimethoxycyclopentadiene in two of the early steps. While fewer steps and higher yield look attractive at first sight, this approach had to be given up due to high cost and restricted availability of the dioxide.

Derivatives

Several derivatives are available, such as the diketone (

melting point The melting point (or, rarely, liquefaction point) of a substance is the temperature at which it changes state of matter, state from solid to liquid. At the melting point the solid and liquid phase (matter), phase exist in Thermodynamic equilib ...

about 322 °C). Both .1.1.1agodane and .2.1.1agodane form

dication A dication is any cation, of general formula X2+, formed by the removal of two electrons from a neutral species. Diatomic dications corresponding to stable neutral species (e.g. formed by removal of two electrons from H2) often decay quickly int ...

s in / . In these cations the

electron deficiency In chemistry, electron deficiency (and electron-deficient) is jargon that is used in two contexts: chemical species that violate the octet rule because they have too few valence electrons and species that happen to follow the octet rule but have el ...

is spread over the central

cyclobutane Cyclobutane is a cycloalkane and organic compound with the formula (CH2)4. Cyclobutane is a colourless gas and is commercially available as a liquefied gas. Derivatives of cyclobutane are called cyclobutanes. Cyclobutane itself is of no commerc ...

ring. These dications were the first examples to show the phenomenon of σ-bishomoaromaticity which was subsequently studied by the Prinzbach group to great length. Pagodane is an isomer of dodecahedrane and can be chemically converted to it.

References

{{reflist, colwidth=30em , refs= Elegant Solutions: Ten Beautiful Experiments in Chemistry Philip Ball RSC 2005 Wolf-Dieter Fessner, Gottfried Sedelmeier, Paul R. Spurr, Grety Rihs, H. Prinzbach (1987), ''"Pagodane": the efficient synthesis of a novel, versatile molecular framework''. J. Am. Chem. Soc., volume 109 issue 15, pp. 4626–42 {{doi, 10.1021/ja00249a029 H. Prinzbach, F. Wahl, A. Weiler, P. Landenberger, J. Woerth, L.T. Scott, M. Gelmont, D. Olevano, F. Sommer, B. von Issendorff: C20 Carbon Clusters: Fullerene – Boat – Sheet Generation, Mass Selection, PE Characterization. Chem. Eur. J. 2006, 12, 6268-6280 , {{doi, 10.1002/chem.200501611 G. K. Surya Prakash (1998), ''Investigations on intriguing long lived carbodications''. Pure & Appl. Chem., volume 70 issue 10, pp. 2001–06
Online version
at iupac.org. Retrieved 2010-01-14. {{doi, 10.1351/pac199870102001 G.K.S. Prakash, V.V. Krishnamurthy, R. Herges, R. Bau, H. Yuan, G.A Olah, W.-D. Fessner, H. Prinzbach: .1.1.1 and .2.1.1agodane Dications: Frozen Two-Electron Woodward-Hoffmann Transition State Models. J. Am. Chem. Soc. 1988, 110, 7764-7772 Wolf-Dieter Fessner, Bulusu A. R. C. Murty, Horst Prinzbach (1987), ''The Pagodane Route to Dodecahedranes – Thermal, Reductive, and Oxidative Transformations of Pagodanes'' Angewandte Chemie International Edition in English Volume 26, Issue 5, pp. 451–52 {{doi, 10.1002/anie.198704511 Wolf-Dieter Fessner, Bulusu A. R. C. Murty, Jürgen Wörth, Dieter Hunkler, Hans Fritz, Horst Prinzbach, Wolfgang D. Roth, Paul von Ragué Schleyer, Alan B. McEwen, Wilhelm F. Maier (1987), ''Dodecahedranes from .1.1.1agodanes''. Angewandte Chemie International Edition in English, Volume 26, Issue 5, pp. 452–54 {{doi, 10.1002/anie.198704521 ''Stable carbocations. Part 267. Pagodane dication, a unique 2.pi.-aromatic cyclobutanoid system'' G. K. Prakash, V. V. Krishnamurthy, Rainer. Herges, Robert. Bau, Hanna. Yuan, George A. Olah, Wolf Dieter. Fessner, and Horst. Prinzbach Journal of the American Chemical Society 1986 108 (4), 836-838 {{doi, 10.1021/ja00264a046 Polycyclic nonaromatic hydrocarbons Cyclobutanes Substances discovered in the 1980s

Synthesis and structure

Derivatives

See also

References