Pagodane
| Pagodane | |
|---|---|
| Stereo, skeletal formula of pagodane | |
| Ball and stick model of pagodane | |
| Identifiers | |
| CAS number | 89683-62-5 7px |
| PubChem | 145202 |
| ChemSpider | 128087 7px |
| Jmol-3D images | Image 1 |
| |
| Molecular formula | C20H20 |
| Molar mass | 260.37 g mol−1 |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) | |
| Infobox references | |
Pagodane is an organic compound with formula C20H20 whose carbon skeleton was said to resemble a pagoda, hence the name. It is a polycyclic hydrocarbon whose molecule has the D2h 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 and chloroform. It sublimes at low pressure.[1]
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 chains. The general member is denoted [m.n.p.q]pagodane where m, n, p and q are the number of carbons of those four chains. The general formula is then C16+sH12+2s where s= m+n+p+q. In particular, the basic compound C20H20 has those carbons connected by four methylene functional groups (m=n=p=q=1), and its name within that family is therefore [1.1.1.1]pagodane.[1]
Synthesis and structure
The compound was first synthesized by H. Prinzbach et al. in 1987, by a 14-step sequence starting from isodrin.[1] In the process they also synthesized [2.2.1.1]pagodane C22H24 and several derivatives.
Prinzbach and co-workers remarked that "the obvious need for [the short name 'pagodane'] can be readily understood in view of the von Baeyer/IUPAC and Chemical Abstracts nomenclature", undecacyclo[9.9.0.01,5.02,12.02,18.03,7.06,10.08,12.011,15.013,17.316,20]icosane.[1]
Eight of pagodane's 20 carbon atoms (numbered 3,5,8,10,13,15,18, and 20) have an inverted tetrahedral geometry as in some propellanes — specifically, [2.2.1]propellane, whose carbon skeleton is a part of pagodane's.[1]
Derivatives
Several derivatives are available, such as the diketone C20H16O2 (melting point about 322 °C).[1]
Both [1.1.1.1]pagodane and [2.2.1.1]pagodane form divalent cations in SbF5/SO2ClF. In these cations the electron deficiency is spread over the central cyclobutane ring.[2]
Pagodane is an isomer of dodecahedrane and can be chemically converted to it.[3][4]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 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, pages 4626–4642 doi:10.1021/ja00249a029
- ↑ G. K. Surya Prakash (1998), Investigations on intriguing long lived carbodications. Pure & Appl. Chem., volume 70 issue 10, pages 2001-2006. [www.iupac.org/publications/pac/70/10/2001/pdf/ Online version] at iupac.org accessed on 2010-01-14. doi:10.1351/pac199870102001
- ↑ 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, Pages 451-452 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 [1.1.1.1]Pagodanes. Angewandte Chemie International Edition in English, Volume 26, Issue 5, Pages 452-454 doi:10.1002/anie.198704521
