Structural Aspects of Lithium Arenethiolate Complexes with Intramolecular Coordinating Amine Donors

Abstract

Reaction of aryllithium reagents LiR (R = C6H4((R)-CH(Me)NMe2)-2 (1a), C6H3(CH2NMe2)2-2,6 (1b), C6H4(CH2N(Me)CH2CH2OMe)-2 (1c)) with 1 equiv of sulfur (1/8 S8) results in the quantitative formation of the corresponding lithium arenethiolates [Li{SC6H4((R)-CH(Me)NMe2)-2}]6 (3), [Li{SC6H3(CH2NMe2)2-2,6}]6 (4), and [Li{SC6H4(CH2N(Me)CH2CH2OMe)-2}]2 (5). Alternatively, 3 can be prepared by reacting the corresponding arenethiol HSC6H4((R)-CH(Me)NMe2)-2 (2) with nBuLi. X-ray crystal structures of lithium arenethiolates 3 and 4, reported in abbreviated form, show them to have hexanuclear prismatic and hexanuclear planar structures, respectively, that are unprecedented in lithium thiolate chemistry. The lithium arenethiolate [Li{SC6H4(CH2N(Me)CH2CH2OMe)-2}]2 (5) is dimeric in the solid state and in solution, and crystals of 5 are monoclinic, space group P21/c, with a = 17.7963(9) Å, b = 8.1281(7) Å, c = 17.1340(10) Å, β = 108.288(5)°, Z = 4, and final R = 0.047 for 4051 reflections with F > 4σ(F). Hexameric 4 reacts with 1 equiv of lithium iodide and 2 equiv of tetrahydrofuran to form the dinuclear adduct [Li2(SAr)(I)(THF)2] (6). Crystals of 6 are monoclinic, space group P21/c, with a = 13.0346(10) Å, b = 11.523(3) Å, c = 16.127(3) Å, β = 94.682(10)°, Z = 4, and final R = 0.059 for 3190 reflections with F > 4σ(F).

Applications of the Laddering Principle — A Two-Stage Approach to Describe Lithium Heterocarboxylates

“…A two‐step approach to laddering is also useful for understanding systems other than lithium heterocarboxylates. For example, the lithium arenethiolate [{Li[SC 6 H 4 {( R )‐CH(Me)NMe 2 }‐2]}] 6 forms a hexamer18 composed of three dimeric PLUs assembled in much the same manner as 2 . Likewise the laddered polymer [PhCH 2 SLi·NC 6 H 5 ] ∞ can be viewed as resulting from the secondary association of monosolvated dimers 19…”

The first compound with an unusual type of anion, [Li(SR)2]–: bis(μ2-aqua-d2)tetrakis(aqua-d2)dilithium(I) bis[bis(tri-tert-butoxysilanethiolato-κ2O,S)lithate(I)] dihydrate-d2

“…The most common lithium thiolates are monomeric (Chadwick & Ruhlandt-Senge, 1998;Ives et al, 2003) or dimeric (Bjernemose et al, 2004;Komuro et al, 2004). However, trimeric (Ruhlandt-Senge et al, 1996;Niemeyer & Power, 1996), hexameric (Janssen et al, 1996) and polymeric forms (Ruth et al, 2005;Hampe et al, 2005) are also known. In the case of lithium compounds, where the most common coordination number is four, the central atoms are frequently coordinated by solvent molecules, with O± and N-donor solvents preferred.…”

(μ-Tri-tert-butoxysilanethiolato)bis[(tetrahydrofuran)lithium(I)] andcatena-poly[[bis(μ-tri-tert-butoxysilanethiolato)dilithium(I)]-μ-dimethoxyethane]: solvent coordination as the structure-forming factor

“…trimers, tetramers or hexamers. A metal coordination number of four is observed for the majority of these compounds (Niemeyer & Power, 1996;Ellison & Power, 1994;Janssen et al, 1996). The structure and chemistry of silanethiolates have been the subject of research by us (Wojnowski et al, 1985(Wojnowski et al, , 1994 and other groups (Kovacs et al, 2000;Komuro et al, 2002Komuro et al, , 2003.…”