Aryllithium compounds, crystal structures

Arylium cations, 9 231, 241-243 Aryllithium compounds, crystal structures, 37 83-85... 

The most straightforward synthesis of compounds (L)AuAr uses the metathesis of (L)AuX precursors with aryllithium reagents, as, for example, executed for the preparation of (Ph3P)AuPh. The crystal structure of this benchmark complex has been determined. The linear coordination geometry is as expected. No aurophilic contacts are discernible in the crystal packing. Short Au- -Au contacts are observed, however, in the dinuclear compound (dppm)(AuPh)2 with an intramolecular intermetallic distance of 3.154(1) A. This complex shows a UV-VIS absorption at 290-300 nm and is luminescent in fluid solution at room temperature.1... 

Crystal Structures of Associated Alkyl-and Aryllithium Compounds and Complexes... 

Yet another variety of self-association via r-interactions was discovered in the solid-state structure of imsolvated 2,4,6-triisopropylphenyllithium. In the crystal this compound forms the tetramer [Li(2,4,6-Pr 3C6H2)]4, 63. This structure has not been observed for other aryllithium species. It consists of an almost planar arrangement of four lithium atoms, each n-bonded to just one phenyl ring (average Li-C distance 2.12 A). In addition, each Li interacts with the 7t-electron system of a... 

---