THE CRYSTAL AND MOLECULAR-STRUCTURES OF HIGHLY SUBSTITUTED CUBANES - 1,2,4,7-TETRA(CARBOXYMETHYL)CUBANE AND 1,2,3,5,7-PENTA(CARBOXYMETHYL)CUBANE

The structures of the title compounds, 1,2,4,7-tetra(carboxymethyl)cub ane 1 and 1,2,3,5,7-penta(carboxymethyl)cubane 2, have been determined . 1 crystallized in the space group P (1) over bar with cell dimension s a = 6.098(2), b = 10.686(2), c = 13.459(2) Angstrom, alpha = 69.82(1 ), beta = 77.01(1), gamma = 74.00(1)degrees, while 2 crystallized in t he monoclinic space group P2(1)/c with cell dimensions a = 15.139(2), b = 12.775(1), c = 9.849(2) Angstrom, beta = 107.01(1)degrees. These m olecules were derived from their parent carboxylic acids by esterifica tion with methanol. They are unusual for several reasons. The first is that they both contain substituents on adjacent carbon atoms in the c ubane framework. There are only a few reports in the literature of thi s type of cubane structure. The second molecule is unique in that it h as five substituents attached to a cubane moiety. This is the one of t he few cubane derivatives with more than four substituents to be struc turally characterized and results in a cubane molecule in which there are three faces with three substituents and three faces with only two substituents.