Lithium–tetrakis(pentafluorophenyl)borate–benzene (1/1/2)

Abstract

The title compound, Li+·C24BF20−·2C6H6, crystallizes as centrosymmetric dimers, with two η6‐coordinated and two uncoordinated mol­ecules of benzene per dimer. There are two crystallographically independent dimers.

Synthesis of Pentafluorophenyl Silver by Means of Lewis Acid Catalysis: Structure of Silver Solvent Complexes

“…∑ r ion (Li + F − ) = 1.90 (CN = 4) and 2.09 (CN = 6) Å) . The known [Li(benzene)][B(C 6 F 5 ) 4 ]·benzene compound crystallizes isotypically as centrosymmetric dimers, also with two η 6 -coordinated and two uncoordinated molecules of benzene per dimer . Similar to [Li(toluene)][B(C 6 F 5 ) 4 ]·toluene, each Li + cation is linked by two [B(C 6 F 5 ) 4 ] anions via short Li···F contacts to form a centrosymmetric dimer.…”

“…35 The known [Li(benzene)][B(C 6 F 5 ) 4 ] 3 benzene compound crystallizes isotypically as centrosymmetric dimers, also with two η 6 -coordinated and two uncoordinated molecules of benzene per dimer. 34 Similar to [Li(toluene)]-[B(C 6 F 5 ) 4 ] 3 toluene, each Li þ cation is linked by two [B(C 6 F 5 ) 4 ] anions via short Li 3 3 3 F contacts to form a centrosymmetric dimer. In addition, the Li þ cation displays a short contact to an F atom of a neighboring [[B(C 6 F 5 ) 4 ] -anion.…”

“…Besides one strongly interacting toluene molecule, which coordinates via all six ring carbon atoms in a η 6 fashion with Li−C distances of 2.515(4)−2.731(4) Å (cf. 2.533(16)−2.751(11) Å in [Li(benzene)][B(C 6 F 5 ) 4 ]·benzene), four F···Li + contacts with three different [B(C 6 F 5 ) 4 ] − ions are observed, resulting in a strongly distorted pseudo-square-pyramidal Li + coordination geometry (toluene considered as one donor). Among these four F···Li + contacts are one bidentate ( d (Li−F14) = 2.210(3) and d (Li−F15) = 2.052(3) Å) and two monodentate coordination modes ( d (Li−F9 i ) = 2.038(3) and d (Li−F18 ii = 2.151(3) Å; cf.…”

A Quest for Ligand‐Unsupported Li+–π Interactions in Mono‐, Di‐, and Tritopic Lithium Arylborates

“…[15] Examples are Lewis base-free phenyllithium ([LiPh] n ), [16] mesityllithium ([LiMes] n ), [17] and 2,4,6-triisopropylphenyllithium ([LiTrip] 4 ); [18] [21] [Li(C 6 H 6 )][Sn{SiMe(tBu) 2 } 3 ], [22] and [Li(C 6 H 6 )][B(C 6 F 5 ) 4 ]. [23] Our own interest in cation-π interactions was sparked by the serendipitous finding that ferrocene reacts with GaCl 3 to give [(C 5 H 5 ) 2 Fe][GaCl 4 ] together with the crystalline Ga I multiple-decker sandwich complex I (Figure 1). [24] By attaching anionic (pyrazol-1-yl)borate substituents to both cyclopentadienyl rings of ferrocene (II; Figure 1), [25][26][27] our group has achieved the targeted synthesis of multipledecker sandwich complexes of ferrocene with the complete series of alkali metals (M + = Li + -Cs + ).…”

New crystal structures of alkali metal tetrakis(pentafluorophenyl)borates

“…the electron poor aromatic rings. By contrast, in the crystal structure of [Li(C 6 H 6 )][B(C 6 F 5 ) 4 ]•benzene (Bolte et al, 2005) and [Li( (Kuprat et al, 2010), the cations show also π-interactions with the electron rich solvate molecules. The cesium salt Cs[B(C 6 F 5 ) 4 ] (2) crystallized in the rare cubic space group I -43d (a = 19.213(1) Å).…”