Über Metallalkyl‐ und ‐aryl‐Verbindungen, XX: Darstellung und Kristallstruktur des dimeren Phenyllithium · N, N, N′, N′‐Tetramethylethylendiamins, Bis[μ‐phenyl‐(N, N, N′, N′‐tetramethylethylendiamin)lithium]

Abstract

Das Addukt Phenyllithium · N, N, N′, N′‐Tetramethylethylendiamin wurde dargestellt und seine Kristallstruktur röntgenographisch ermittelt (R = 0.066, 1595 signifikante Reflexe). Die monokline Elementarzelle (Raumgruppe C2/c) enthält 4 Moleküle eines Dimeren. Ähnlich wie im dimeren Triphenylaluminium sind in jedem Molekül zwei Li‐Atome durch zwei Phenyl‐Gruppen verbrückt. Durch die Anlagerung eines Diamin‐Liganden erreicht jedes Li‐Atom vierfache Koordination.

Vicinal 2H/1H Isotope Shifts for 6Li‐NMR and the Aggregation Behavior of Phenyllithium

“…Considering the three aggregates 13-15 where X-ray data are available for the solidthe tetramer coordinated with Et,O [7], the dimer complexed with TMEDA [8], and the monomer complexed with PMDTA [9] -the magnitude of the observed isotope shift per neighbouring Ph group shows an inverse correlation with the average C-Li distance found in the solid : 7.0, 10.4, and 19.2 ppb us. 231, 224, and 214 pm, respectively.…”

“…--Because of its importance as a synthetic reagent, numerous efforts have been made to uncover the structure of phenyllithium in the solid as well as in solution. X-Ray investigations have characterized the tetramer 13, crystallized from Et,O [7], the dimer 14 which crystallizes as a complex with tetramethylethylenediamine (TMEDA) from the same solvent in the presence of the donor ligand [8], and the monomer 15, stabilized through complexation with the tridentate ligand pentamethyldiethylenetriamine (PMDTA) [9].…”

A Homoleptic Carbene-Lithium Complex

“…[16,17] This arrangement . [18,19] The LiC 4 coordination geometry is highly twisted forming a tetrahedron that is ªflattened on one sideº: the C4A-Li1-C4 angle of 111.8(2)8 approaches the ideal tetrahedral angle, the C7-Li1-C4 angle (92.7(2)8) is compressed, and the C3A-Li1-C7 angle (140. 3(2)8) is greatly expanded.…”

Diastereoselective Self-Assembly of Chiral Diamine-Chelated Aryllithiums to Dimeric Aggregates

“…The overall structural motif as observed in the solid-state of these compounds, vide supra, closely resembles that of [LiPh(TME-DA)] 2 . 11 (In fact these compounds may be regarded as PhLi containing an intramolecularly connected ortho-ethylenediamine unit.) A difference is the orientation of the aryl ring with respect to the C ipso -Li-C ipso -Li plane.…”

“…In [LiPh(TMEDA)] 2 the aryl rings are oriented perpendicular to this plane. 11 In 1b, 6 2b, and (R)-3b, the dihedral angles are 63. Before discussing the observed data in detail, the various implications of the stereochemical aspects of this type of compounds will be outlined.…”