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Lanthanoid‐Based Ionic Liquids Incorporating the Dicyanonitrosomethanide Anion
Author(s) -
Chesman Anthony S. R.,
Yang Mei,
Spiccia Nicolas D.,
Deacon Glen B.,
Batten Stuart R.,
Mudring AnjaVerena
Publication year - 2012
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201103379
Subject(s) - melting point , lanthanide , ionic liquid , chemistry , crystallography , hydrogen bond , ion , crystal structure , inorganic chemistry , medicinal chemistry , molecule , organic chemistry , catalysis
A series of low‐melting‐point salts with hexakisdicyanonitrosomethanidolanthanoidate anions has been synthesised and characterised: (C 2 mim) 3 [Ln(dcnm) 6 ] ( 1 Ln ; 1 Ln = 1 La , 1 Ce , 1 Pr , 1 Nd ), (C 2 C 1 mim) 3 [Pr(dcnm) 6 ] ( 2 Pr ), (C 4 C 1 pyr) 3 [Ce(dcnm) 6 ] ( 3 Ce ), (N 1114 ) 3 [Ln(dcnm) 6 ] ( 4 Ln ; 4 Ln = 4 La , 4 Ce , 4 Pr , 4 Nd , 4 Sm , 4 Gd ), and (N 1112OH ) 3 [Ce(dcnm) 6 ] ( 5 Ce ) (C 2 mim=1‐ethyl‐3‐methylimidazolium, C 2 C 1 mim=1‐ethyl‐2,3‐dimethylimidazolium, C 4 C 1 py= N ‐butyl‐4‐methylpyridinium, N 1114 =butyltrimethylammonium, N 1112OH =2‐(hydroxyethyl)trimethylammonium=choline). X‐ray crystallography was used to determine the structures of complexes 1 La , 2 Pr , and 5 Ce , all of which contain [Ln(dcnm) 6 ] 3− ions. Complexes 1 Ln and 2 Pr were all ionic liquids (ILs), with complex 3 Ce melting at 38.1 °C, the lowest melting point of any known complex containing the [Ln(dcnm) 6 ] 3− trianion. The ammonium‐based cations proved to be less suitable for forming ILs, with complexes 4 Sm and 4 Gd being the only salts with the N 1114 cation to have melting points below 100 °C. The choline‐containing complex 5 Ce did not melt up to 160 °C, with the increase in melting point possibly being due to extensive hydrogen bonding, which could be inferred from the crystal structure of the complex.