CARBAZOLE DEPROTONATION BY SODIUM METAL MIRROR IN VARIOUS ETHERS, STRUCTURES WITH NA-3 AND NUMBER-4 TO NUMBER-7( COORDINATION NUMBER)

Solutions of carbazole anions and sodium cations in aprotic ethers suc h as tetrahydrofuran, dimethoxyethane, diglyme, triglyme, tetraglyme, 15-crown-5 or 2.2.1-cryptand form a cation solvation system with a sha llow potential and numerous local minima. Its experimental exploration allows to crystallize and structurally characterize contact ion multi ples of Na+-solvated carbazole anion M- salts comprising polyether-sol vated monomers [M-Nasolv+](1), solvent-shared dimers [M-Nasolv+](2) an d solvent-separated polyions [(M-)(n)Na-solv(+)]((n-1)-)[Na-solv(+)](( n-1)). Their Na+ coordination numbers stretch from 3 to 7. Series of c ompounds, shape-selected from the same crystallization batch such as 3 - and 7-coordinate [(M-)(3)Na+](2-)[Na+(2.2,1-cryptand)](2), 4- and 7- coordinate [(M-)(2)Na+(THF)(2)](-)[Na+(2.2.1-cryptand)] as well as sol vent-separated [M-][Na+(2.2.1-cryptand)] suggest potential cation solv ation equilibria in the reductive deprotonation mixtures. The seven di fferent carbazolate sodium salts presented, therefore, demonstrate the delicate energy balance, by which cation solvation can influence the crystallization of individual molecular crystals. (C) 1997 Elsevier Sc ience S.A.