Group I The Alkali and Coinage Metals

Arena Radical-anion and Dianion Species. The esr spectra of Maph , Na (1) in THF and THF-df exhibit slight differences some H/D exchange occurs on prolonged standing of ( ) in THF-da. The crystal structures of air- and moisture-sensitive [(HesSl)tC(][Li(THF)Ja, (1), obtained from Li and (Me3Sl)(Ca in THF at RT, has been determined both Li cations (Li—-Li = 2.722 A) are located on the same side of the dianion boat-shape ring. 

An ab initio calculation, uv and imr spectra suggest this boat-form persists In solution. In contrast to that in (D, the dlanlon ring in air-and moisture-sensitive [l,2,4,5-(Me5Sl) C H2][LiDME]j ( ), is nearly planar with [LiDME] above and below the plane of the ring. An ab initio 

MejSiCHtSlMeaCHLl.THED Li is bonded to 1C, 2N, and IH of a Me group of an adjacent molecule (L1-—H 2.33 A). (11) [(MexP)(Me,Si),CLl THF], idiich contains a 6-membered chair-shaped rlng with Li bonded to bridging P, 1C and 1 0, (lii) [(Me,Sl) CLi]i, obtained from (Me,Sl),CHgBr and BuLi hae a LiiCx 

Arvl-alkali Metal Compounds. Formation of o-FC(H K has been achieved at -100 C from PhF and BuLi/Bu OK in TBF/hexane llthlation ortho to F occurs in p-FCcH SR and in o-FCfH SPr but with o-FC(H SMe, o-FCtH SCHsLl is obtained. Both [2-F-6-PhS0tC HsLi.PMDTA] QO) and [3-Br-2-Ll-benzofuran.Pr tO] (J2) are stable to -elimination of LiX (X-Br or F) upto 60 C. 

Crystal structures have been determined for (i) (10) Li bonded to 3N, anionic C and 0, (il) (11) - a trans dimer with bridging anionic C Li bonded to C and 0 of 1 anion, to anionic C of the other and to 0 of OPr t, (ill) [o-Ph PCcH L1.0Eti]t (12) Li bonded to C, 0 and 2 bridging P and (Iv) [2,6-(Bu 0)aC(HsLl] (13) Li is intramolecularly bonded to 0 some 0 atoms are pyramidal. Ah initio calculations have been carried out on (12). (13) and C(Li( (1 ) lowest energy form of (14) consists of an inner hexagon of carbons, surrounded by 6 Li atoms in bridging positions.  

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