TY - JOUR
T1 - Structure of 1-alkyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl) amide ionic liquids with linear, branched, and cyclic alkyl groups
AU - Kashyap, Hemant K.
AU - Santos, Cherry S.
AU - Murthy, N. Sanjeeva
AU - Hettige, Jeevapani J.
AU - Kerr, Kijana
AU - Ramati, Sharon
AU - Gwon, Jinhee
AU - Gohdo, Masao
AU - Lall-Ramnarine, Sharon I.
AU - Wishart, James F.
AU - Margulis, Claudio J.
AU - Castner, Edward W.
PY - 2013/12/12
Y1 - 2013/12/12
N2 - X-ray scattering and molecular dynamics simulations have been carried out to investigate structural differences and similarities in the condensed phase between pyrrolidinium-based ionic liquids paired with the bis(trifluoromethylsulfonyl)amide (NTf2-) anion where the cationic tail is linear, branched, or cyclic. This is important in light of the charge and polarity type alternations that have recently been shown to be present in the case of liquids with cations of moderately long linear tails. For this study, we have chosen to use the 1-alkyl-1-methylpyrrolidinium, Pyrr 1,n+ with n = 5 or 7, as systems with linear tails, 1-(2-ethylhexyl)-1-methylpyrrolidinium, Pyrr1,EtHx+, as a system with a branched tail, and 1-(cyclohexylmethyl)-1-methylpyrrolidinium, Pyrr1,ChxMe+, as a system with a cyclic tail. We put these results into context by comparing these data with recently published results for the Pyrr1,n+/NTf2- ionic liquids with n = 4, 6, 8, and 10.1,2 General methods for interpreting the structure function S(q) in terms of q-dependent natural partitionings are described. This allows for an in-depth analysis of the scattering data based on molecular dynamics (MD) trajectories that highlight the effect of modifying the cationic tail.
AB - X-ray scattering and molecular dynamics simulations have been carried out to investigate structural differences and similarities in the condensed phase between pyrrolidinium-based ionic liquids paired with the bis(trifluoromethylsulfonyl)amide (NTf2-) anion where the cationic tail is linear, branched, or cyclic. This is important in light of the charge and polarity type alternations that have recently been shown to be present in the case of liquids with cations of moderately long linear tails. For this study, we have chosen to use the 1-alkyl-1-methylpyrrolidinium, Pyrr 1,n+ with n = 5 or 7, as systems with linear tails, 1-(2-ethylhexyl)-1-methylpyrrolidinium, Pyrr1,EtHx+, as a system with a branched tail, and 1-(cyclohexylmethyl)-1-methylpyrrolidinium, Pyrr1,ChxMe+, as a system with a cyclic tail. We put these results into context by comparing these data with recently published results for the Pyrr1,n+/NTf2- ionic liquids with n = 4, 6, 8, and 10.1,2 General methods for interpreting the structure function S(q) in terms of q-dependent natural partitionings are described. This allows for an in-depth analysis of the scattering data based on molecular dynamics (MD) trajectories that highlight the effect of modifying the cationic tail.
UR - http://www.scopus.com/inward/record.url?scp=84884304547&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84884304547&partnerID=8YFLogxK
U2 - 10.1021/jp403518j
DO - 10.1021/jp403518j
M3 - Article
C2 - 23750608
SN - 1520-6106
VL - 117
SP - 15328
EP - 15337
JO - Journal of Physical Chemistry B
JF - Journal of Physical Chemistry B
IS - 49
ER -