Two derivatives of lithium isodicyclopentadienide: [(1,2,3,3a,7a-eta)-4,5,6,7-tetrahydro-4,7-methanoindenido](N,N,N'N'-tetramethylethylenediamine)lithium and bis(1,4,7,10-tetraoxacyclododecane)lithium(1+) Bis[(1,2,3,3a,7a-eta)-4,5,6,7-tetrahydro-4,7-methanoindenido]lithate(1-)

Selective crystallization of a solution of lithium isodicyclopentadienide, (isodiCp)Li, in dry thf or diethyl ether under argon has produced two lithium complexes: (isodiCp)Li(TMEDA), [Li(C10H11)(C6H16N2)], (4), and [Li(12-crown-4)2](+).[Li(isodiCp)(2)](-), [Li(C8H16O4)(2)]-[Li(C10H11)(2)], (5). In (4) the Li+ ion is coordinated to the two N atoms of the disordered TMEDA and is eta(5)-coordinated to the Cp ring of the isodiCp ligand. The Li-(Cp ring centroid) distance is 1.906(7) Angstrom. In (5) there are two independent half-molecules of the anion and one molecule of the cation in the asymmetric unit. In each anion, the Li+ ion occupies a crystallographic inversion center and is eta(5)-coordinated to the two Cp rings of two isodiCp ligands. The Cp rings are in a staggered arrangement, as required by the inversion center. The Li-(Cp ring centroid) distances for the two anions are 1.987(3) and 2.008(3)Angstrom. In the cation of (5), the Li+ ion is co-ordinated to two 12-crown-4 ligands, one of which is disordered. Both (4) and (5) exhibit exo coordination of the Li+ ion to the isodiCp ligand, with a resultant slight endo bending of this ligand.