Synthesis and properties of novel chiral-amine-functionalized ionic liquids

A novel class of chiral-amine-functionalized ionic liquids (CAFILs) has been synthesized efficiently from natural amino acids, and their structures have been determined by spectroscopic analysis and low temperature X-ray diffraction analysis. The CAFILs have been characterized by physical properties such as melting point, glass transition temperature, thermal degradation and specific rotation. NMR measurements indicate that the CAFILs may be promising alternatives in the field of chiral discrimination.

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1-[(S)-(2-Amino)propyl]-3-methylimidazolium bromideC7H14N3Br[α]D20=+12.6 (c 2, EtOH)Source of chriality: (S)-alalineAbsolute configuration: (S)

1-[(S)-(2-Amino)propyl]-3-methylimidazolium tetrafluoroborateC7H14N3F4B[α]D20=+13.9 (c 2, EtOH)Source of chriality: (S)-alalineAbsolute configuration: (S)

1-[(S)-(2-Amino)propyl]-3-methylimidazolium hexafluorophosphateC7H14N3F6P[α]D20=+7.2 (c 2, EtOH)Source of chriality: (S)-alalineAbsolute configuration: (S)

1-[(S)-(2-Amino)-3-methylpentyl]-3-methylimidazolium bromideC9H18N3Br[α]D20=+10.3 (c 2, EtOH)Source of chriality: (S)-valineAbsolute configuration: (S)

1-[(S)-(2-Amino)-3-methylpentyl]-3-methylimidazolium tetrafluoroborateC9H18N3F4B[α]D20=+6.9 (c 2, EtOH)Source of chriality: (S)-valineAbsolute configuration: (S)

1-[(S)-(2-Amino)-3-methylpentyl]-3-methylimidazolium hexafluorophosphateC9H18N3F6P[α]D20=+4.6 (c 2, EtOH)Source of chriality: (S)-valineAbsolute configuration: (S)

1-[(S)-(2-Amino)isohexyl]-3-methylimidazolium bromideC10H20N3Br[α]D20=+6.0 (c 2, EtOH)Source of chriality: (S)-leucineAbsolute configuration: (S)

1-[(S)-(2-Amino)isohexyl]-3-methylimidazolium tetrafluoroborateC10H20N3F4B[α]D20=+7.1 (c 2, EtOH)Source of chriality: (S)-leucineAbsolute configuration: (S)

1-[(S)-(2-Amino)isohexyl]-3-methylimidazolium hexafluorophosphateC10H20N3F6P[α]D20=+5.4 (c 2, EtOH)Source of chriality: (S)-leucineAbsolute configuration: (S)

1-[(S)-(2-Amino)-3-methylpentyl]-3-methylimidazolium bromideC10H20N3Br[α]D20=+11.7 (c 2, EtOH)Source of chriality: (S)-isoleucineAbsolute configuration: (R)

1-[(S)-(2-Amino)-3-methylpentyl]-3-methylimidazolium tetrafluoroborateC10H20N3F4B[α]D20=+10.1 (c 2, EtOH)Source of chriality: (S)-isoleucineAbsolute configuration: (R)

1-[(S)-(2-Amino)-3-methylpentyl]-3-methylimidazolium hexafluorophosphateC10H20N3F6P[α]D20=+3.9 (c 2, EtOH)Source of chriality: (S)-isoleucineAbsolute configuration: (R)

1-[(S)-(2-Pyrrolidinyl)methyl]-3-methylimidazolium bromideC9H16N3Br[α]D20=+6.5 (c 2, EtOH)Source of chriality: (S)-prolineAbsolute configuration: (S)

1-[(S)-(2-Pyrrolidinyl)methyl]-3-methylimidazolium tetrafluoroborateC9H16N3F4B[α]D20=+4.5 (c 2, EtOH)Source of chriality: (S)-prolineAbsolute configuration: (S)

1-[(S)-(2-Pyrrolidinyl)methyl]-3-methylimidazolium hexafluorophosphateC9H16N3F6P[α]D20=+2.7 (c 2, EtOH)Source of chriality: (S)-prolineAbsolute configuration: (S)