Two Derivatives of Lithium Isodicyclopentadienide: [(1,2,3,3a,7a-η)-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-η)-4,5,6,7-tetrahydro-4,7-methanoindenido]lithate(1–)

Abstract

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) A. 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) A. In the cation of (5), the Li+ ion is coordinated 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.

Solvate Structures and Computational/Spectroscopic Characterization of LiBF4 Electrolytes

“…From a previously reported phase diagram, the formation of the (AN) 4 :LiBF 4 solvate ( T m = −13 °C) was confirmed, and it was assumed to be an SSIP solvate, despite the lack of a known crystal structure, as for the known (AN) 4 :LiClO 4 and (AN) 4 :LiI solvate crystal structures. , The formation of a (12C4) 2 :LiBF 4 solvate ( T m = 110 °C) was confirmed with elemental analysis (a crystal structure could not be determined for this solvate). This is also postulated to be a SSIP solvate, as is found for all of the many known (12C4) 2 :LiX solvate crystal structures. − The anion Raman band for both of these solvates is located in the same position as for the (G2) 2 :LiBF 4 solvate (Supporting Information). Furthermore, the anion band for the three HBF 4 solvates with uncoordinated anions (Figure ) is also found positioned with these other SSIP solvate bands (Figure ) (Supporting Information), as expected.…”

Solvate Structures and Computational/Spectroscopic Characterization of Lithium Difluoro(oxalato)borate (LiDFOB) Electrolytes

“…Attempts were made to determine the crystal structures of the (12C4) 2 :LiDFOB, (G2) 2 :LiDFOB, and (HMTETA) 1 :LiDFOB solvates, but these efforts were unsuccessful due to the very energetic solid–solid phase transitions which occur for these solvates at low temperature (SI) and the presence of significant disorder within the solvate structures in the higher temperature phases. There are no reported crystal structures yet known for solvates with HMTETA and LiX salts, but (12C4) 2 :LiX − and (G2) 2 :LiX ,− solvates are well-knownall of which have uncoordinated anions (i.e., SSIP solvates). The band positioned near 710 cm –1 for all three speculative SSIP solvates remains relatively fixed over the entire temperature range (Figures and ).…”

Metallocene Anions: From Electrochemical Curiosities to Isolable Complexes

“…[25] The first structurally characterised example of a group 1 derivatized metallocene anion, [Li(12-crown-4) 2 ][Li-(isodiCp) 2 ] (isodiCp = isodicyclopentadienide), was reported in 1994 by Gautheron and Paquette to form from the reaction of [Li(isodiCp)(THF) n ] with 12-crown-4 (Scheme 2). [26,27] The structural parameters of the [Li(isodiCp) 2 ] À anion were found to be similar to [PPh 4 ][Li(Cp) 2 ] and [(TAS)(Cp)]Li(Cp) 2 ]. [16][17][18] Structurally authenticated examples of isolated derivatized [M(Cp R ) 2 ] À anions for M C Li, Na and K have been reported periodically in the interim; [28][29][30][31][32][33][34][35] a full description is beyond the scope of this review.…”