Aqua-(μ-cone-26,28-dibut-oxy-25,27-bis-{N-[5-(dimethyl-amino)-naphthalene-1-sulfon-yl]carbamoylmeth-oxy}-5,11,17,23-tetra-kis-(1,1-dimethyl-eth-yl)calix[4]arene(2-))disodium acetonitrile tetra-solvate.

The structure of the title complex, [Na(2)(C(80)H(98)N(4)O(10)S(2))(H(2)O)]·4CH(3)CN, obtained after crystallization from aceto-nitrile, contains two formula units in the asymmetric unit (Z' = 2) and an estimated four mol-ecules of acetonitrile per calixarene moiety. It is unusual for two Na(+) ions to occupy the lower rims of the cone calix[4]arene, as in this case, with one Na(+) ion forming two O→ Na(+) coordinate bonds with the two but-oxy groups and four such bonds with the two N-dansyl carboxamide groups, forming six dative bonds between Na(+) and O. On the other hand, the other Na(+) ion forms only five O→Na(+) coordinate bonds on the far end of the calix[4]arene lower rim, bringing the two dansyl groups in close proximity with each other. There also appears to be an O→Na(+) coordination coming from a dangling water mol-ecule. The structure contained both resolved and poorly resolved solvent mol-ecules. The latter were treated using the SQUEEZE routine in PLATON [Spek (2009 ▶). Acta Cryst. D65, 148-155].