METAL ALKYL AND METAL ARYL COMPOUNDS .24. SYNTHESIS AND CRYSTAL-STRUCTURE OF TRIPHENYLMETHYLSODIUM TETRAMETHYLETHYLENEDIAMINE

The title compound has been prepared and investigated by X-ray diffraction (monoclinic space group P21/n, Z = 4, 2456 reflexions, R = 0.07). The structure resembles that of Ph3CLi ⋯ tmeda (tmeda = N,N,N′,N′-tetramethylethylenediamine) and can be described as a contact ion pair of a triphenylmethyl carbanion and a sodium ion coordinated to the bidentate ligand tmeda. The Na ion has close contacts to several C atoms of the π-carbanion (264 pm to the central C(methyl) atom, 288-309 pm to two adjacent C atoms of two phenyl groups). A further short distance (296 pm) exists between Na and a p-C(phenyl) atom of a neighbouring carbanion. Each carbanion is planar in its central part but has twisted and elongated phenyl groups. © 1979.