TY - JOUR
T1 - Structural Characterization of Lithium and Sodium Bulky Bis(silyl)amide Complexes
AU - Nicholas, Hannah
AU - Goodwin, Conrad
AU - Kragskow, Jon G. C.
AU - Lockyer, Selena
AU - Mills, David
PY - 2018/5
Y1 - 2018/5
N2 - Alkali metal amides are vital reagents in synthetic chemistry and the bis(silyl)amide {N(SiMe3)2} (N′′) is one of the most widely-utilized examples. Given that N′′ has provided landmark complexes, we have investigated synthetic routes to lithium and sodium bis(silyl)amides with increased steric bulk to analyse the effects of R-group substitution on structural features. To perform this study, the bulky bis(silyl)amines {HN(SitBuMe2)(SiMe3)}, {HN(SiiPr3)(SiMe3)}, {HN(SitBuMe2)2}, {HN(SiiPr3)(SitBuMe2)} and {HN(SiiPr3)2} (1) were prepared by literature procedures as colourless oils; on one occasion crystals of 1 were obtained. These were treated separately with nBuLi to afford the respective lithium bis(silyl)amides [Li{μ-N(SitBuMe2)(SiMe3)}]2 (2), [Li{μ-N(SiiPr3)(SiMe3)}]2 (3), [Li{N(SitBuMe2)2}{μ-N(SitBuMe2)2}Li(THF)] (4), [Li{N(SiiPr3)(SitBuMe2)}(DME)] (6) and [Li{N(SiiPr3)2}(THF)] (7) following workup and recrystallization. On one occasion during the synthesis of 4 several crystals of the ‘ate’ complex [Li2{μ-N(SitBuMe2)2}(μ-nBu)]2 (5) formed and a trace amount of [Li{N(SiiPr3)2}(THF)2] (8) was identified during the recrystallization of 7. The reaction of {HN(SitBuMe2)2} with NaH in the presence of 2 mol % of NaOtBu gave crystals of [Na{μ-N(SitBuMe2)2}(THF)]2 (9-THF), whilst [Na{N(SiiPr3)2}(C7H8)] (10) was prepared by deprotonation of 1 with nBuNa. The solid-state structures of 1–10 were determined by single crystal X-ray crystallography, whilst 2–4, 7, 9 and 10 were additionally characterized by NMR and FTIR spectroscopy and elemental microanalysis.
AB - Alkali metal amides are vital reagents in synthetic chemistry and the bis(silyl)amide {N(SiMe3)2} (N′′) is one of the most widely-utilized examples. Given that N′′ has provided landmark complexes, we have investigated synthetic routes to lithium and sodium bis(silyl)amides with increased steric bulk to analyse the effects of R-group substitution on structural features. To perform this study, the bulky bis(silyl)amines {HN(SitBuMe2)(SiMe3)}, {HN(SiiPr3)(SiMe3)}, {HN(SitBuMe2)2}, {HN(SiiPr3)(SitBuMe2)} and {HN(SiiPr3)2} (1) were prepared by literature procedures as colourless oils; on one occasion crystals of 1 were obtained. These were treated separately with nBuLi to afford the respective lithium bis(silyl)amides [Li{μ-N(SitBuMe2)(SiMe3)}]2 (2), [Li{μ-N(SiiPr3)(SiMe3)}]2 (3), [Li{N(SitBuMe2)2}{μ-N(SitBuMe2)2}Li(THF)] (4), [Li{N(SiiPr3)(SitBuMe2)}(DME)] (6) and [Li{N(SiiPr3)2}(THF)] (7) following workup and recrystallization. On one occasion during the synthesis of 4 several crystals of the ‘ate’ complex [Li2{μ-N(SitBuMe2)2}(μ-nBu)]2 (5) formed and a trace amount of [Li{N(SiiPr3)2}(THF)2] (8) was identified during the recrystallization of 7. The reaction of {HN(SitBuMe2)2} with NaH in the presence of 2 mol % of NaOtBu gave crystals of [Na{μ-N(SitBuMe2)2}(THF)]2 (9-THF), whilst [Na{N(SiiPr3)2}(C7H8)] (10) was prepared by deprotonation of 1 with nBuNa. The solid-state structures of 1–10 were determined by single crystal X-ray crystallography, whilst 2–4, 7, 9 and 10 were additionally characterized by NMR and FTIR spectroscopy and elemental microanalysis.
KW - bis(silyl)amid
KW - ligand
KW - lithium
KW - Sodium
U2 - 10.3390/molecules23051138
DO - 10.3390/molecules23051138
M3 - Article
SN - 1420-3049
VL - 23
JO - Molecules
JF - Molecules
IS - 5
ER -