Adamanzane
Adamanzanes (abbreviated Adz) are compounds containing four nitrogen atoms linked by carbons (analogous to adamantane with nitrogen at the branched position). 

Often coordinated to a central ligand, the nitrogens occupy the vertices of a tetrahedron, with potentially four faces and six edges, with the carbon chains running approximately along the edges.  They can have a "bowl" or "cage" structure, with varying lengths or omission of the carbon chains.  In the nomenclature of Springborg et al. (1996) these can be described according to the number of chains of specified length: thus, for example, [14.22]adamanzane is 1,3,6,8-tetraazatricyclo[4.4.1.13,8]dodecane, a compound which contains four one-carbon chains and two two-carbon chains linking the nitrogen atoms.

[36]Adamanzane has found a special use in the preparation of "inverse sodium hydride", a compound in which Na− and H+ ions coexist, due to the ability of the adamanzane to encapsulate the H+ and render it kinetically inert to react with the Na−.

References 

Nitrogen heterocycles
Adamantane-like molecules
Heterocyclic compounds with 3 rings