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Chiral Ionic Liquid Technologies
Dr. Mukund Ghavre
Project AimProject Aim Synthesis and characterisation of a library of Synthesis and characterisation of a library of
novel achiral and chiral ionic liquids (ILs) novel achiral and chiral ionic liquids (ILs) containing ester and amide functionality.containing ester and amide functionality.
Evaluation of the antimicrobial toxicity and Evaluation of the antimicrobial toxicity and biodegradability of those ILs.biodegradability of those ILs.
Investigation of the effects of the ester moiety, Investigation of the effects of the ester moiety, oxygen-containing side-chain and anion on the oxygen-containing side-chain and anion on the toxicity and biodegradability of the IL.toxicity and biodegradability of the IL.
Comparison of toxicities and Comparison of toxicities and biodegradability data of various cation biodegradability data of various cation cores of achiral and chiral ILs.cores of achiral and chiral ILs.
Employment of the suitable ILs as reaction Employment of the suitable ILs as reaction media in catalytic reactions.media in catalytic reactions.
Application of low toxicity and readily Application of low toxicity and readily biodegradable ILs in solar cells as biodegradable ILs in solar cells as electrolyte.electrolyte.
IntroductionIntroduction Ionic Liquids can be simply defined as organic Ionic Liquids can be simply defined as organic
salts having melting point bellow 100salts having melting point bellow 100°°C.C.11
They are regarded as ‘Green Solvents’ due to They are regarded as ‘Green Solvents’ due to their physical properties.their physical properties.
The properties exhibited by ILs are low vapour The properties exhibited by ILs are low vapour pressure, non-flammability, high dielectric pressure, non-flammability, high dielectric constant, low volatility, wide electrochemical constant, low volatility, wide electrochemical window, low surface tension and high thermal window, low surface tension and high thermal stability.stability.1. P. Wasserscheid, W. Keim, 1. P. Wasserscheid, W. Keim, Angew. Chem., Int. Ed., 2000, Angew. Chem., Int. Ed., 2000, 39, 3772-3789. 39, 3772-3789.
The first IL was reported by P. Walden The first IL was reported by P. Walden in 1914 which was [EtNHin 1914 which was [EtNH33][NO][NO33].].22
However, the first application based IL However, the first application based IL was [EtPy][AlClwas [EtPy][AlCl44] synthesised by a duo ] synthesised by a duo Hurley and Weir in 1948 and utilised Hurley and Weir in 1948 and utilised for electrodeposition of Al.for electrodeposition of Al.33
Since then three generation of ionic Since then three generation of ionic liquids have been introduced by the liquids have been introduced by the researchers.researchers.2. P. Walden, Bull. Acad. Imper. Sci., 1914, 1, 405-422.
3. F. Hurley, U. S. Patent 4 446 331, 1948 .
SynthesisSynthesis
In order to prepare biodegradable ILs In order to prepare biodegradable ILs ester and amide functionalities were ester and amide functionalities were incorporated in the structure while incorporated in the structure while designing them. This design was also designing them. This design was also based on the previous results obtained based on the previous results obtained in our group.in our group.
BrBr
O
R OH+Esterification
rt, 12 h ORBr
O
NN
NN OR
O
BrNN OR
O
X
rt, 12 h
MX
rt, 4-12 h
Where R = alkyl group MX = LiNTf2, NaOctSO4, NBu4I, NaN(CN)2, AgOAc
NN N
O
ONN N
O
ON N
O
O
NN NHDec
O
N NHDec
O
NN N
O
O
O
NN O
O O OBu
1 2
3
a = Brb = [NTf2]c = [OctOSO3]d = I
5 6 7
4
NN
O
O
OO
Br
213
45
67
8 9
10 11
12
13
14
Lactate and substituted mandelate cores Lactate and substituted mandelate cores were chosen as cations of CILs as these were chosen as cations of CILs as these are naturally available substrates. And are naturally available substrates. And also breakdown enzymes are available in also breakdown enzymes are available in microbes which would facilitate microbes which would facilitate biodegradability. biodegradability.
The synthesis of these ILs consist of four The synthesis of these ILs consist of four steps.steps.44
4. S. Morrissey, B. Pegot, D. Coleman, M. Garcia, D. Ferguson, B. Quilty, N. Gathergood, Green Chem., 2009, 11, 475–483.
NN
rt, 12 h
R1 = H, OH.
R2 = OH, Br, OCF3, OCH3.
R1+R2 = OCH2O.
R3 = Me, Et, Bu.
X = Br, Cl. MY = LiNTf2, NaOctSO4.
+
Bromoacetyl bromide,
Na2CO3 or TEA,
0°C to rt
R1
R2H
O
OH
O
R1
R2
OH
OH
O
R1
R2
OH
OR3
O
R1
R2
X
OR3
O
R1
R2
O
OR3
O
O
Br
SOX2, TEA
0°C to rt
R1
R2
O
OR3
O
O
NN
BrR1
R2
O
OR3
O
O
NN
Y
R1
R2
N
OR3
O
N
X
R1
R2
N
OR3
O
N
Y
NN
rt, 12 h
Method A: Alcohol, SOCl2, 3 h, rt
Method B: Alcohol, PTSA, 6 h, rt
MY, rt,4-12 h
MY, rt,4-12 h
Monoester IL
Diester IL
Where
Al2O3, NaOH,
60°C, 24 h
or H2SO4,
-10°C to rt, 24 h
OOR
O
O
NN
OOR
O
O
NN
R = Methyl (8) Ethyl (9) Butyl (10) Pentyl (11)X = Br (a) [OctOSO3] (c)
X X
R = Methyl (12) Ethyl (13) Butyl (14)X = Br (a) [OctOSO3] (c)
O
O
O
O
N
O
O
N
X
N
OBu
O
N
Br
O
O
N
OBu
O
Br
O
O
O
O
O
O
N
O
O
NBu
X
15
16 X = Br (17a) [NTf2] (b) [OctOSO3] (c)
X = Br (18a) [NTf2] (b) [OctOSO3] (c)
O
O
O
O
N
O
O
XO
O
N
O
O
N
Br
Br
O
O
N
O
O
N
X
H3CO
O
O
N
O
O
N
X
F3C
X = Br (19a) [NTf2] (b)
20a
X = Br (21a) [NTf2] (b) [OctOSO3] (c)
X = Br (22a) [NTf2] (b)
ToxicityToxicity
Limited data is known about Limited data is known about
the toxicity of ILs.the toxicity of ILs.
As ILs are being considered As ILs are being considered
as green solvents, it is as green solvents, it is
important to estimate their fate important to estimate their fate
when released into the environment. when released into the environment.
The toxicity screening was performed at The toxicity screening was performed at this faculty and biodegradation studies this faculty and biodegradation studies were carried out in Spain. were carried out in Spain.
NN N
O
ONN N
O
ON N
O
O
NN NHDec
O
N NHDec
O
NN N
O
O
O
NN O
O O OBu
1 2
3
a = Brb = [NTf2]c = [OctOSO3]d = I
5 6 7
4
Antibacterial screening of ILs
Bacteria :
1. SA Staphylococcus aureus CCM 4516/08
2. MRSA Staphylococcus aureus H 5996/08
3. SE Staphylococcus epidermidis H 6966/08
4. EF Enterococcus sp. J14365/08
5. EC Escherichia coli CCM 4517
6. KP Klebsiella pneumoniae D 11750/08
7. KP-E Klebsiella pneumoniae J 14368/08
8. PA Pseudomonas aeruginosa CCM 1961
No. Bacteria
strain
Time (h)
MIC/IC95 (mM)
2a-b,d 5a-b, 6a-b, 7a-b, 1d
1b 3a 3b 3c 4a 4b 4c
1. SA 48h > 2.0 > 1.0 0.125 0.0625 0.03125 0.125 0.0625 0.03125
2. MRSA 48h > 2.0 > 1.0 0.125 0.125 0.125 0.125 0.125 0.0625
3. SE 48h > 2.0 > 1.0 0.0625 0.25 0.50 0.125 0.125 0.0625
4. EF 48h > 2.0 > 1.0 0.125 0.125 0.125 0.25 0.125 0.0625
5. EC 48h > 2.0 > 1.0 0.50 0.25 0.25 0.125 0.125 0.0625
6. KP 48h > 2.0 > 1.0 1.0 0.25 0.50 0.50 0.25 0.25
7. KP-E 48h > 2.0 > 1.0 1.0 0.25 1.0 0.50 0.125 0.50
8. PA 48h > 2.0 > 1.0 1.0 > 1.0 2.0 0.50 1.0 1.0
Antifungal screening of ILsAntifungal screening of ILs
Fungi :
1. CA1 Candida albicans ATCC 44859 7. CG Candida glabrata 20/I
2. CA2 Candida albicans ATCC 90028 8. CL Candida lusitaniae 2446/I
3. CP Candida parapsilosis ATCC 22019 9. TB Trichosporon beigelii 1188
4. CK1 Candida krusei ATCC 6258 10. AF Aspergillus fumigatus 231
5. CK2 Candida krusei E28 11. AC Absidia corymbifera 272
6. CT Candida tropicalis 156 12. TM Trichophyton mentagrophytes 445
No Fungi strain
Time (h)
MIC/IC80.IC50 (mM)a
1d, 2a-b,d 5-7 (a, b)
1b 3a 3b 3c 4a 4b 4c
1. CA1 48h > 2.0 > 1.0 0.250 0.250 0.125 0.250 0.5 0.125
2. CA2 48h > 2.0 > 1.0 0.125 0.250 0.125 0.250 0.250 0.125
3. CP 48h > 2.0 > 1.0 0.0625 0.125 0.125 0.0625 0.125 0.0625
4. CK1 48h > 2.0 > 1.0 0.0078 0.0313 0.0625 0.0156 0.0156 0.0156
5. CK2 48h > 2.0 > 1.0 0.0039 0.0313 0.0625 0.0156 0.0156 0.0078
6. CT 48h > 2.0 > 1.0 0.0039 0.0313 0.0625 0.0156 0.0156 0.0039
7. CG 48h > 2.0 > 1.0 0.0625 0.125 0.125 0.125 0.125 0.125
8. CL 48h > 2.0 > 1.0 0.250 0.250 0.250 0.250 0.250 0.125
9. TA 48h > 2.0 > 1.0 0.250 0.5 0.250 0.250 0.5 0.125
10. AF 48h > 2.0 > 1.0 0.250 0.5 0.250 0.250 0.250 0.125
11. AC 48h > 2.0 > 1.0 0.250 > 1.0 1.0 0.250 > 0.5 1.0
12. TM 120h > 2.0 > 1.0 0.250 0.250 0.125 0.250 0.250 0.125
a IC50 values were assessed for AF, AC and TM. For all other fungi strains IC80 values were evaluated.
It is a process in which organic It is a process in which organic compounds are broken down into simpler compounds are broken down into simpler molecules by the action of molecules by the action of microorganisms.microorganisms.55
BiodegradationBiodegradation
5. P. Howard, R. Boethling, W. Stiteler, W. Meylan, J. Beauman, Sci. Total Environ., 1991, 109, 635-641.
OOBu
O
O
NN
10c
OctOSO3
O
O
O
O
N
O
O
N
X
X = Br (17a) [NTf2] (17b)
O
O
O
O
N
O
O
XO
O
N
O
O
N
NTf2
H3CO
X = Br (19a) [NTf2] (19b)
21b
IL Biodegradation (%)
6 days 13 days 21 days 28 days
SDS 73 91 92 93±2.5
10c 52 57 61 62±1.0
17a 17 21 61 60±2.2
17b 11 46 52 60±0.9
19a 35 59 63 75±3.7
19b 26 51 73 80±1.5
21b 33 64 63 64±0.9
Applications
Applications
Achiral ILs were chosen as media for Achiral ILs were chosen as media for Tsuji-Trost reactions. Tsuji-Trost reactions.
Media in Tsuji-Trost Media in Tsuji-Trost ReactionsReactions
NN N
O
O
O
NTf2NN O
O O
NTf2
OBu
NN N
O
NTf2
NN N
O
NTf2O
1b 2b
5b 7b
NN N
O
O
O
2f
NN N
O
O
O
OctOSO3
2c
OAc
Entry IL Temp. (°C) Time (h) Yield (%) ee (%) (S)
1 [bmim][PF6]6 RT 15 31 86
2 2b RT 15 38 87
3 2ba RT 15 61 83
4 2bb RT 15 75 48
5 7b RT 15 47 64
6 5b RT 15 43 94
7 2c RT 15 58 44
8 2f RT 15 54 49
9 1bc RT 15 27 80
10 2bc RT 15 21 96
11 2bc 40 15 37 92
12 THF RT 15 61 79
13 DMSO RT 15 62 97
Reaction conditions: The reactions were performed under Ar atmosphere using IL (1.0 eq.), dimethyl malonate (2.0 eq.), Pd2(dba)3 (2 mol%), (S,S)-iPr-phospherrox (8 mol%), KOAc (2.0 eq.), bis(trimethylsilyl)acetamide (2.0 eq.); a Pd2(dba)3 (4 mol%), b R-BINAP (8 mol%), c K2CO3 was used instead of KOAc/BSA.6. I. Kmentova, B. Gotov, E. Solcaniova, S. Toma, Green Chem., 2002, 4,
103-106.
Dye sensitised Solar Dye sensitised Solar CellsCells
Traditional organic solvents (for instance Traditional organic solvents (for instance acetonitrile, propionitrile) being used in acetonitrile, propionitrile) being used in DSSCs have limitations such as high DSSCs have limitations such as high volatility, low chemical, thermal and volatility, low chemical, thermal and electrochemical stability, toxicity hence electrochemical stability, toxicity hence ionic liquids were used as replacements.ionic liquids were used as replacements.77
As our ILs were found to exhibit low As our ILs were found to exhibit low toxicity, we decided to screen them in toxicity, we decided to screen them in solar cells as electrolyte. solar cells as electrolyte.
7. M. Gratzel et al. , Nature Materials, 2008, 7, 626-630.
NN N
O
O
O
NN O
O O OBu
NN N
O
O
1 2
7
XX
X
NN O
O
22
X
X = Br (a) [NTf2](b) I (f)
Results of IL screening in DSSCResults of IL screening in DSSC
TiOTiO22: 7+2 (P: 7+2 (P2525+200 nm)[TiCl+200 nm)[TiCl44 pre + post pre + post
treatment].treatment].
DyeDye: N719 Dyesol: N719 Dyesol
Electrolyte compositionsElectrolyte compositions: : DMII/X/EMITCB/IDMII/X/EMITCB/I22/NBB/GNCS /NBB/GNCS
(12/12/16/1.67/3.33/0.67)(12/12/16/1.67/3.33/0.67)
X Jsc (mA/cm2) Voc (V) FF (%) Eff (%)
EMII 11.5 0.669 64 4.94
1a 7.23 0.638 52 2.38
1b 7.19 0.625 62 2.79
1f 8.95 0.622 53 2.92
2a 6.30 0.662 60 2.51
2b 6.97 0.630 60 2.61
2f 8.85 0.620 62 3.39
7a 6.97 0.640 52 2.30
7b 5.15 0.660 72 2.46
7f 9.27 0.667 53 3.31
22a 8.83 0.655 65 3.76
22f 10.4 0.675 56 3.92
ConclusionConclusion In this project overall seventy two novel In this project overall seventy two novel
ILs were synthesised and characterised.ILs were synthesised and characterised.
In most of the cases they were found to be In most of the cases they were found to be non-toxic up to the test limit (2 mM) non-toxic up to the test limit (2 mM) except for the long chain (C10) amides or except for the long chain (C10) amides or esters.esters.
Six chiral ILs were found to be readily Six chiral ILs were found to be readily biodegradable.biodegradable.
When employed in Tsuji-Trost reactions, When employed in Tsuji-Trost reactions, better enantioselectivity was achieved with better enantioselectivity was achieved with our ILs.our ILs.
The application of our ILs in DSSCs showed The application of our ILs in DSSCs showed moderate efficiency, however, more moderate efficiency, however, more research is needed to improve the results.research is needed to improve the results.
Application of these ester/amide based ILs Application of these ester/amide based ILs revealed that they are not appropriate revealed that they are not appropriate choice of media for base catalysed choice of media for base catalysed reactions. reactions.
Thank Thank you !you !
