MONO-ORTHO-CHELATED AND BIS-ORTHO-CHELATED LITHIUM AND SODIUM PHENOLATES - MOLECULAR-STRUCTURES OF THE 1ST LITHIUM PHENOLATE WITH A STABLE,TRINUCLEAR STRUCTURE AND OF A TETRANUCLEAR SODIUM ANALOG, [MOC6H2(CH2NME2)2-2,6-ME-4]X (M = LI, X = 3, M = NA, X = 4)

The lithium and sodium phenolates of 2-[(dimethylamino)methyl]phenol, 1a and 2a, 2-[(dimethylamino)methyl]-4,6-dimethylphenol, 1b and 2b, an d 2,6-bis[(dimethylamino)methyl]-4-methylphenol, 1c and 2c, respective ly, have been synthesized. The structures of these complexes in soluti on were studied by variable-temperature H-1 and C-13 NMR spectroscopy and cryoscopic molecular weight measurements. The solid-state structur es of complexes 1c and 2c derived from 2,6-bis[(dimethylamino)methyl]- 4-methylphenol, were determined by X-ray diffraction. The complexes co ntaining only one ortho-chelating (dimethylamino)methyl group, i.e. la ,b and 2a,b, are soluble in weakly polar solvents, like tetrahydrofura n. Complexes la and lb are tetramers in benzene. These tetramers occur in solution in-two isomeric forms, i.e. as aggregates with D2 and S4 symmetry. The lithium ''pincer-phenolate'' containing two ortho-chelat ing (dimethylamino)methyl groups (1c) is a trimer in apolar solvents a s well as in the solid-state. It is the first example of a phenolate c omplex with a stable, trinuclear structure. In contrast, the sodium an alog (2c) is a dimer in solution and crystallizes as a tetramer with a cubic-like Na4O4 core. Crystals of Li3C39H63N6O3, lc,are monoclinic, space group P2(1)/n, with unit cell dimensions a = 42.381(5) angstrom, b = 8.8417(11) angstrom, c = 11.1802(10) angstrom, beta = 90.539(8)-d egrees, and Z = 4. The structure was refined to R = 0.068 for 4106 ref lections and 610 parameters. The trimeric structure contains a Li3O3-r ing which is almost perfectly planar (within 0.05 angstrom), and very short Li-O and C-O bond lengths (averages of 1.865(9) and 1.317(6) ang strom, respectively). As a result of intramolecular amine coordination lc is a ''propeller-like'' molecule with screw-type chirality. Crysta ls of Na4C52Hg4N8O4.C6H6, 2c, are monoclinic, space group P2/c, with a = 16.021(2) angstrom, b = 10.275(1) angstrom, c = 24.190(2) angstrom, beta = 130.35(1)-degrees, Z = 2, and final R = 0.064 for 3476 reflect ions and 400 parameters. This tetramer consists of a double dimer in w hich the NMe2 groups of one dimer do exclusively coordinate to the sod ium atoms of the same dimer.