Synthesis and electrochemical evaluation of 2-substituted imidazolium salts

Article abstract of DOI:10.1002/poc.3784

Herein, we report the synthesis, electrochemical, and computational evaluation of six 2-substituted imidazolium bromides and six 2-substituted imidazolium triflates. All final compounds were obtained in 2 or fewer synthetic steps from inexpensive starting

Full text of DOI:10.1002/poc.3784

Received: 28 July 2017
DOI: 10.1002/poc.3784
Revised: 18 September 2017
Accepted: 30 September 2017
R E S E A R C H A R T I C L E
Synthesis and electrochemical evaluation of 2‐substituted
imidazolium salts
David T. Hogan
| Todd C. Sutherland
Department of Chemistry, University of
Calgary, Calgary, Canada
Abstract
Herein, we report the synthesis, electrochemical, and computational evaluation
of six 2‐substituted imidazolium bromides and six 2‐substituted imidazolium
triflates. All final compounds were obtained in 2 or fewer synthetic steps from
inexpensive starting materials and display a single, irreversible electrochemical
reduction. The reduction potentials span a range greater than 1 V depending on
the electron withdrawing power of the 2‐substituent. Imidazolium bromides
such as Bn2(H)ImBr reduce with E1/2 = −2.70 V vs Fc/Fc+, whereas the elec-
tron‐withdrawing Br‐containing analog Bn2(Br)ImBr reduces at only −1.58 V
vs Fc/Fc+. The reduction potential of imidazolium bromides obeys a linear free
energy relationship to σm Hammett constants, whereas imidazolium triflates
correlate better with the σp Hammett constants. These results indicate that the
stabilizing effect of the 2‐substituent is anion‐sensitive, changing from induction
to resonance upon exchanging bromide for triflate. Predicted electron affinities
from density functional theory–optimized structures of imidazolium cations and
reduced species more closely match experimental data for the triflates, suggest-
ing that a triflate anion does not electronically perturb the imidazolium core as
much as a bromide. Taken together, these data highlight the dual modularity of
imidazolium salts by changing both 2‐substituent and anion.
Correspondence
Todd C. Sutherland, Department of
Chemistry, University of Calgary, 2500
University Dr NW, T2N 1N4 Calgary,
Canada.
Email: todd.sutherland@ucalgary.ca
Funding information
Natural Sciences and Engineering
Research Council of Canada, Grant/
Award Number: RGPIN/04444‐2014
KEYWORDS
density functional calculations, electrochemistry, linear free energy relationships, nitrogen
heterocycles, substituent effects
1 | INTRODUCTION
by the myriad of review articles in this field.[3–8] The solu-
tion‐phase catholyte and anolyte in RFBs are stored in
Renewable resource‐based electricity generation—such as
wind, solar, and tidal—is poised to contribute an increas-
ingly greater percentage of global energy demand over the
coming decades.[1,2] However, these intermittent forms of
electricity generation are often geographically and tempo-
rally dependent and thus are difficult to synchronize with
demand. Grid‐scale energy storage can overcome this lim-
itation—of available methods, the technology of redox‐
flow batteries (RFBs) is gaining momentum as evidenced
large tanks, enabling scalability of the system and poten-
tial for large‐scale energy storage. Early successful RFBs
relied on expensive and toxic inorganic active electrolytes
such as chromium[9] and vanadium.[10,11] Remaining in
tune with the renewable aspect of this technology,
research on organic materials has produced many viable
active electrolytes. Recent examples include N,N′‐dialkyl
viologens,[12,13]
nones,[14,15] and Sanford's cyclopropenium salts.[16]
polysulfonated
benzo/anthraqui-
J Phys Org Chem. 2017;e3784.
wileyonlinelibrary.com/journal/poc
Copyright © 2017 John Wiley & Sons, Ltd.
1 of 15
https://doi.org/10.1002/poc.3784

2 of 15
HOGAN AND SUTHERLAND
Prototype batteries using these active electrolytes
displayed low degradation and >95% coulombic efficiency
over at least 100 cycles.
erature. To our knowledge, there has been no electro-
chemical investigation on a breadth of 2‐substituted
imidazolium salts.
Designing new organic active electrolytes can be a
lengthy process when accounting for many technical fac-
tors. At minimum, the molecule must exhibit fully revers-
ible redox processes, fast electron‐transfer kinetics, be
highly soluble in the carrier solvent at all states of charge,
and be stable for tens of thousands of charge/discharge
cycles.[6,7] We selected the imidazolium core as a building
block (Chart 1) to synthesize new organic anolytes
because the first reduced species is a neutral radical. Imid-
azole‐type structures have been used for decades to stabi-
lize otherwise reactive classes of compounds[17] such as
the N‐heterocyclic carbenes,[18,19] triphenylimidazolyl
radicals,[20,21] and some of Bertrand's cyclic (amino)
(carboxy) radicals.[22,23] Our design involves substitution
at the 2‐position of the imidazole ring to impart extra
thermodynamic stability to a radical or anion and
the use of bulky N‐benzyl groups to enhance kinetic
persistence (Chart 1). There are few reports on 2‐
substituted imidazoliums from the N‐heterocyclic
carbenes community because a 2‐H is commonly required
for deprotonation and formation of the carbene.[24–26] N‐
quaternarized imidazoles known as imidazolium
salts are a common motif in the field of ionic liquids
(ILs) because of their modular core. Recently, some ILs
have been used as supporting electrolytes in RFBs because
of their high dielectric constant and wide electrochemical
potential window.[27,28] However, this application
remains uncommon, and there are no reports of any
imidazoliums being investigated as active electrolytes in
RFBs. Applying 2‐substituted imidazoliums in this
manner requires rigorous understanding of their electro-
chemical behavior, which constitutes a gap in current lit-
Electrochemical characterization revealed that all 12
imidazolium salts display a single, irreversible reduction
between −2.84 and −1.22 V vs Fc/Fc+, demonstrating a
distinct sensitivity of the reduction potentials towards
the nature of each 2‐substituent. Furthermore, we found
that exchanging anion from bromide to triflate repre-
sented a second method for redox property modulation:
Magnitude of reduction potential followed a different
trend depending on the anion. Hammett analysis of the
2‐substituent effect for each anion quantitatively con-
firmed the observed trends such that reduced
imidazolium bromides experience inductive stabilization,
whereas reduced triflates are resonance‐stabilized. Exper-
imental results are complemented by density functional
theory (DFT) calculations, supporting 2‐substituent effect
on reduction potentials, which correlate best with
imidazolium triflates.
2 | RESULTS AND DISCUSSION
2.1 | Synthesis
Synthesis of the imidazolium salts began with double N‐
benzylation of commercially available imidazole (1a), 2‐
methylimidazole (1b), and 2‐phenylimidazole (1c) using
a modified literature procedure, shown in Scheme 1.[29]
This di‐benzylation afforded the first 3 imidazolium bro-
mides to be investigated—Bn2(H)ImBr, Bn2(CH3)
ImBr, and Bn2(Ph)ImBr—with varying 2‐substitution
in one step. The coordinating nature of the anion for ILs
is known to affect the electronic structure of the
imidazolium core,[30] because bromides and other halides
CHART 1 Synthesis of imidazolium salts Bn2(SCH3)ImX,
Bn2(Br)ImX, and Bn2(CHO)ImX with proposed aldehyde‐
hydrate equilibrium
SCHEME
investigated in this work
1
Structures of 2‐substituted imidazolium salts

HOGAN AND SUTHERLAND
3 of 15
coordinate strongly, whereas bulkier anions such as
triflate coordinate only weakly. Stemming from our inter-
est in studying the electronic structure of the imidazolium
core, we decided to briefly explore this anion effect. Anion
exchange under inert atmosphere with methyl triflate[31]
yielded the triflate salts Bn2(H)ImOTf, Bn2(CH3)
ImOTf, and Bn2(Ph)ImOTf. While full purification of
the imidazolium triflates by conventional means was
unsuccessful (section 2 in Supporting Information), diag-
nostic shifts in all proton resonances were observed by
1H NMR. Completing ion exchange with AgOTf instead
of MeOTf provided NMR‐pure materials for analysis (sec-
tion 2 in Supporting Information). Most notable among
the resonances was the 2‐H proton in Bn2(H)ImOTf,
which experienced significantly more shielding (9.3 ppm
vs 11.1 ppm) than in its analogous bromide salt, highlight-
ing the weakly coordinating nature of triflate (section 3 in
Supporting Information).[30]
Accessing imidazolium salts with more exotic 2‐sub-
stitution than simple hydrocarbons required a different
synthetic strategy than that in Scheme 1, because the
required imidazoles were too costly for large‐scale synthe-
sis (Scheme 2). Lithiation of commercially available 1‐
benzylimidazole (2), followed by electrophilic quenching
of the anion is a well‐documented strategy that has
been successful for introducing a variety of groups at
the 2‐position.[32–35] For synthetic versatility, we targeted
2‐bromo 3a, 2‐(methylsulfanyl) 3b, and 2‐formyl 3c
derivatives, which could serve as platforms for
further functionalization. Successful lithiation of 1‐
benzylimidazole was confirmed by observing a brilliant
red solution upon adding n‐BuLi, whereas addition of
the electrophilic reagent (either NBS, (CH3)2S2 or DMF)
caused the red color of the anion to dissipate. After chro-
matographic purification, three 2‐substituted imidazoles
3a‐c were isolated in 49%, 80%, and 86% yields,
respectively.
Oxidation of 1‐benzyl‐2‐(methylsulfanyl)imidazole
(3b) was used to access higher oxidation states of the sul-
fur atom, as shown in Scheme 3. Treatment with hydro-
gen peroxide in acetic acid at slightly elevated
temperature selectively formed the partially oxidized 2‐
sulfoxide 4a, whereas increased temperature caused full
oxidation to the 2‐sulfone 4b. The ability to obtain 2 prod-
ucts in good yields with only slight modification of condi-
tions reveals the utility of this mild oxidation protocol
reported by Vampa and coworkers.[36] With five 2‐
substituted imidazoles in hand, benzylation of the
remaining imidazole N to form the desired imidazolium
salts was investigated, as shown in Scheme 4. Gentle
treatment of 2‐(methylsulfanyl) 3b with 1 equivalent of
benzyl bromide led to selective alkylation of the imidazole
N, forming the salt Bn2(SCH3)ImBr in 38% yield. A by‐
product of this reaction was identified as imidazol‐2‐
thione 5. We propose that the thione formation resulted
from demethylation by the noninnocent bromide anion,
releasing methyl bromide. Both selective N‐alkylation
SCHEME 3 Divergent synthesis of 2‐substituted imidazoles from
1‐benzylimidazole 2
SCHEME 2 Synthesis of Bn2(H)ImX, Bn2(CH3)ImX, and
Bn2(Ph)ImX from commercially available 2‐substituted imidazoles
SCHEME 4 Selective oxidation of 2‐(methylsulfanyl) 3b to 2‐
sulfoxide 4a and 2‐sulfone 4b

4 of 15
HOGAN AND SUTHERLAND
and demethylation behaviors have been observed by
Metzger and coworkers with similar imidazoliums.[37]
Bn2(SCH3)ImBr was susceptible to demethylation even
at room temperature in solution but was indefinitely sta-
ble in the solid state. Anion exchange with methyl triflate
afforded triflate salt Bn2(SCH3)ImOTf, as determined by
diagnostic proton resonance shifts in the 1H NMR (section
3 in Supporting Information). N‐benzylations of 2‐sulfox-
ide 4a and 2‐sulfone 4b in CH3CN resulted in only trace
conversion as observed by thin layer chromatography
(TLC) even after 2 weeks at 80°C. The decreased reactivity
could be ascribed to the presence of strong electron with-
drawing groups near the nucleophilic N. Forcing condi-
tions in neat benzyl bromide at 50°C resulted in the
complete conversion of 2‐sulfoxide 4b in 1 day (TLC),
but the resulting imidazolium salt could not be isolated
with acceptable purity. Under the same forcing condi-
tions, only trace conversion of 2‐sulfone 4b was observed
after 2 weeks at 50°C, so the N‐benzylation of 4a and 4b
were abandoned. Conversion of 2‐bromoimidazole 3a into
its respective imidazolium salt Bn2(Br)ImBr proceeded
smoothly in 88% in 1 day using neat benzyl bromide,
followed by anion exchange with methyl triflate to form
Bn2(Br)ImOTf (Scheme 4). N‐benzylation of 2‐formyl‐
imidazole 3c produced the salt Bn2(CHO)ImBr as deter-
mined by HR MS and 1H NMR; however, further analysis
indicated H2O‐sensitivity through hydrate formation
(section 3 in Supporting Information). The imidazolium
bromide was still converted to its triflate salt Bn2(CHO)
ImOTf by anion exchange (Scheme 4).
FIGURE 1 Differential pulse voltammetry (black) and cyclic
voltammetry (red) of approximately 1‐mM Bn2(Ph)ImBr (top)
and Bn2(Br)ImBr (bottom) in dry DMF with approximately 0.5‐M
(n‐Bu)4NBF4 as supporting electrolyte
stability window at potentials between −2.9 and −1.3 V vs
Fc/Fc+, which are summarized in Table 1. Bn2(Br)ImX
and Bn2(CHO)ImX are unique among the imidazolium
salts in that the electron withdrawing groups permit 2
irreversible reductions in the solvent window (Figure 1).
Upon switching solvent to CH3CN, the same irreversible
behavior is observed in all cases. The irreversible
electrochemical response of imidazoliums bearing an H
2.2 | Electrochemistry
With the 12 imidazolium bromides and triflates in hand,
we next evaluated the redox properties of the salts. The
electrochemical behavior of the imidazolium bromides
was investigated using cyclic voltammetry (CV) and dif-
ferential pulse voltammetry (DPV). Figure 1 shows the
electrochemical evaluation of Bn2(Ph)ImBr using both
CV and DPV, whereas voltammograms for remaining
imidazoliums can be found in section 4 of the Supporting
Information. The E1/2 values were taken from the apex of
the DPV traces, once corrected for the internal standard.
Representatively, the DPV (top trace) and CV (bottom
trace) of Bn2(Ph)ImBr is shown in Figure 1. The DPV
trace clearly shows 2 peaks as the potential is swept from
positive to negative, demonstrative of reduction of the
internal ferrocene standard and Bn2(Ph)ImBr at
−2.34 V. The CV of Bn2(Ph)ImBr mirrors the same
peaks as DPV, but the technique highlights the irrevers-
ibility of the electrochemical reduction reaction. All of
the imidazoliums investigated undergo irreversible elec-
trochemical reduction reactions within the solvent
TABLE 1 Reduction half‐wave potentials of synthesized
imidazolium bromides and triflates
E1/2 (V)a
E1/2 (V)a
Compound Code
Bn2(H)ImX
X = Br
X = OTf
−2.70
−2.77
Bn2(CH3)ImX
Bn2(Ph)ImX
Bn2(SCH3)ImX
Bn2(Br)ImX
−2.84
−2.72
−2.34
−2.32
−2.16
−2.22
−1.58/−2.70
−1.73/−2.70
−1.74/−2.68
−1.22/−1.90
Bn2(CHO)ImX
aE1/2 referenced against Fc/Fc+ measured by differential pulse voltammetry
in approximately 1‐mM dry DMF solutions.

HOGAN AND SUTHERLAND
5 of 15
atom at the 2‐position has been previously studied by
NMR and MS analysis of the decomposition products,[38]
and it has been postulated that one‐electron reduction
forms the imidazol‐2‐yl radical, which undergoes bimo-
lecular disproportionation into the imidazol‐2‐ylidene
and the 2,3‐dihydroimidazole. Clyburne and coworkers
supported this claim with CV studies of 1,3‐bis(mesityl)
imidazolium chloride where intermediacy of the radical
was followed by decomposition to the carbene.[39,40]
The reduction potentials in Table 1 of imidazolium
bromides and triflates demonstrates the remarkable tun-
ability of this system—simply by exchanging H for Br,
the electrochemical reduction potential shifts over 1 V.
Given the variety of imidazoliums studied, a trend in the
reduction potentials became apparent.
More rigorously, the reduction potentials were evalu-
ated by using the Hammett equation to identify a linear
free energy relationship between 2‐substituent on the
imidazolium and the Hammett substituent constant.[41,42]
This approach has been successful for a broad array of
studies including fulleroid electrochemistry,[43] rates of
benzylic radical dimerization,[44] and photochromic
spiropyran isomerization.[45] The imidazolium bromide
and triflate reduction half‐wave potentials were plotted
against both meta and para Hammett substituent con-
stants, and linear fits were applied, as shown in Figure 2.
Note that only the most linear relationships are shown in
Figure 2, and the comparison of linear fits can be seen in
Figure S12a‐b. For the bromide series, both σm and σp pro-
duced linear fits with slopes greater than 1, suggesting
that the imidazolium system is more sensitive to substitu-
ent effects than benzoic acid.[46] However, a superior cor-
relation is observed using σm, which suggests that the
substituent at the 2‐position contributes more induction
than resonance to stabilizing the reduced imidazolium.[42]
For the triflate series, there is a marked change in the
half‐wave potentials compared to the bromides, again
supporting the notion of a tighter ion‐pairing interaction
between the imidazolium and bromide. This ion pairing
effect occurs despite electrochemical investigation being
performed in 0.5‐M (n‐Bu)4NBF4, in which a loosely
bound counterion would exchange readily in solution.
The most significant difference between the reduction
potentials for the imidazolium bromides and triflates is
the reversal between Bn2(Br)ImX and Bn2(CHO)ImX:
Bn2(Br)ImBr is easier to reduce than Bn2(CHO)ImBr,
but for the triflates, the opposite is observed, by over
500 mV. This observation suggests that the imidazolium
salt anion influences the electronic properties of the core.
To probe this effect, the triflate series' reduction half‐wave
potentials were plotted against Hammett substituent con-
stants, to identify a free energy relationship, as shown in
Figure 2.[42,46] Strikingly, the imidazolium triflates corre-
late more closely with σp than σm, which is opposite to
the behavior of the bromides. Although the preference
for σp is slight, it indicates that the nature of the 2‐substit-
uent stabilizing effect on the reduced species is in part
dependent on the anion, which is supported by the con-
clusions of Maier and coworkers' detailed spectroscopic
work on the effect of imidazolium anions.[30]
While the stabilizing effect of the chosen 2‐substit-
uents has a marked influence on the ease of reduction,
that stabilization appears to have little effect on the
reversibility of the electron transfer. The chemical irre-
versibility of Bn2(H)ImBr is attributable to dispropor-
tionation of the nascent radical because of transfer of
the 2‐H atom, but the other 5 imidazolium bromides
do not share this trait. Electrochemical investigations
of Bn2(SCH3)ImBr probed the nature of this irrevers-
ibility. To discount slow electron transfer kinetics, var-
iable scan rate CV was done between 10 and
1000 mV·s‐1 (Figures S7a and S8a) and no trace of an
anodic current is observable, suggesting instead an
ensuing chemical reaction after reduction. Coulombic
analysis was then conducted to determine the number
of electrons accepted during reduction, the diffusion
coefficients of Bn2(SCH3)ImBr, and ferrocene being
comparable (Figures S7a‐b and S8a‐d). Linear scan
voltammetry from +1.0 V to −1.9 V on an equimolar
DMF solution of Bn2(SCH3)ImBr and ferrocene pro-
duced a voltammogram with 2 peaks of near‐equal
FIGURE 2 Free energy relationship diagram of imidazolium
triflates using σp constants (top); imidazolium bromides using σm
constants (bottom). The red lines are linear fits of the data

6 of 15
HOGAN AND SUTHERLAND
area (approximately 0.97:1) (Figure S11). Because fer-
rocene oxidation is a 1‐electron process, this close
match in integrated charge of equimolar solutions sug-
gests that Bn2(SCH3)ImBr reduction is also 1‐elec-
tron, forming an imidazolyl radical. These radicals
are well documented in the literature, most notably
as the photochromic hexaarylbisimidazole systems,
composed of dimerized imidazolyl radicals.[20,21,47,48]
Given their propensity towards dimerization, we pro-
pose that the nascent radicals of imidazolium bromides
and triflates readily dimerize after single electron
reduction, which would be the origin of their irrevers-
ible CV behavior.
Bn2(H)Im• in Figure 3. The large spin density on C2 of
the radicals may suggest that dimerization involves that
position, which has been observed previously for
imidazolyl radicals.[21,53] Such literature precedents fur-
ther support the proposal for a chemical reaction follow-
ing the electrochemical reduction of the imidazolium
salts. In addition, after in silico reduction followed by
reoptimization at the same level of theory, there are nota-
ble structural changes due to electronic perturbation of
the system. In all cases, the N─C2 and N─backbone C4
and C5 bonds lengthen and backbone C═C bonds con-
tract. The new bond lengths are more reminiscent of C,
N single and C,C double bonds. Interestingly, the C2─2‐
substituent bond lengthens for all radicals save Bn2(Ph)
Im• and Bn2(CHO)Im•, because these 2 radicals have
significant spin delocalization onto the phenyl ring and
carbonyl group, which explains the observed contraction.
In the literature, there are several methods of varying
accuracy for calculating reduction potentials. The most rig-
orous involves a thermodynamic cycle for the initial and
reduced species to compute free energies for reduction and
solvation, which was not undertaken here.[54–57] However,
a modest approximation of the reduction potential—or
more accurately the electron affinity (EA)—used in this
work involves optimizing the initial and reduced species in
a continuum solvent to account for reorganization and per-
turbation energy upon adding an electron.[54] This method
is advantageous over assuming that the LUMO energy alone
is a good measure of electron affinity. The electron affinity
of the imidazolium cations was calculated as suggested by
Banerjee and coworkers, and the results are shown in
Table 2.[54] The results were then compared to experimental
LUMO energies for imidazolium bromides and triflates in
Figure 4 obtained from DPV apex peaks with ferrocene as
internal standard (EHOMO = −4.8 eV).[58] The correlation
between experiment and theory here is acceptable and high-
lights the utility of this simple computational method, given
the poor fitting observable between experimental and calcu-
lated LUMO energies alone, which does not account for
molecular reorganization (Figures S13a‐b). Imidazolium
triflates correlate slightly better to the ideal cationic core,
which could reveal the nature of this anion. Triflate is a
weakly coordinating anion and likely does not associate
2.3 | Theoretical calculations
To gain further insight into the reduction of the
imidazolium core, we conducted DFT calculations using
the Gaussian 09 package.[49] Structures of the
imidazolium cations and their single electron reduced
radicals were optimized with the B3LYP functional[50,51]
using the 6‐31G+(d) basis set, solvated in DMF using
the polarizable continuum model.[52] Expectedly, the
imidazolium core of all cations is planar and bears large
LUMO coefficients (section 5 in Supporting Information).
In particular, the LUMO of Bn2(H)Im+ cation, shown in
Figure 3, has a large lobe on C2, which is also common
between Bn2(CH3)Im+ and Bn2(SCH3)Im+ (section 5
in Supporting Information). This DFT result is in agree-
ment with both a resonance understanding of the struc-
ture and PM3 QM calculations of Kroon et al.[38] The
localization of the LUMOs also justifies our design of
these molecules—placing electron‐withdrawing groups
at the imidazolium 2‐position would have the greatest
effect. The LUMOs of Bn2(Ph)Im+ and Bn2(CHO)Im+
differ slightly from the rest because they exhibit coeffi-
cients over the phenyl ring and the carbonyl group. Upon
in silico reduction to the imidazolyl radicals, the calcu-
lated spin densities largely correlate with the LUMO coef-
ficients of the cations, with one general exception: There
is no spin‐density on the benzyl Ph rings (section 5 in
Supporting Information). This effect is demonstrated with
FIGURE 3 Density functional theory–
optimized structures of Bn2(H)Im+ with
LUMO surface (left) and Bn2
• with
(H)Im
spin density surface (right), using B3LYP
functional and 6‐31G+(d) basis set

HOGAN AND SUTHERLAND
7 of 15
TABLE 2 Calculated electron affinities for imidazolium cations
were needed to acquire each system. Furthermore, we
observed that using a bromide or triflate anion influences,
both the reduction potential and the dominant stabilizing
effect of the 2‐substituent on the electrochemically
reduced species. Namely, reduced imidazolium bromides
are stabilized through induction, whereas reduced
triflates are stabilized by resonance. DFT‐calculated EAs
provided theoretical support for the differentiation
of anions, indicating that the core of imidazolium bro-
mides is more electronically perturbed than in the
analogous imidazolium triflates. Electronic effects from
altering 2‐substituent and anion highlight the dual
modularity of imidazolium salts, paving the way for
further comprehensive investigations into 2‐substituted
imidazolium systems.
Bn2(R)Im+
Cation Code
Bn2(H)Im+
EAa (eV)
2.07
Bn2(CH3)Im+
Bn2(Ph)Im+
Bn2(SCH3)Im+
Bn2(Br)Im+
2.00
2.40
2.48
3.47
3.65
Bn2(CHO)Im+
aEA calculated by subtracting optimized radical UB3LYP energy from cation
RB3LYP energy and converting to eV. Calculations completed using B3LYP,
6‐31G+(d) basis set and PCM DMF solvent model.
4 | EXPERIMENTAL
4.1 | General information
All 1H NMR spectra were collected at 400 MHz
and 13C{1H} NMR spectra at 100 MHz on a Bruker
1
DRY400 spectrometer at 298 K. H NMR and 13C{1H}
NMR spectra were referenced against the residual solvent
signals from CHCl3 in CDCl3 (1H δ = 7.26, 13C δ = 77.2),
(CD2H)(CD3)SO in (CD3)SO (1H δ = 2.50, 13C δ = 39.5), or
CD2HCN in CD3CN (1H δ = 1.94, 13C δ = 1.3).[59] High‐
resolution mass spectra (HR MS) were collected using
either EI on a Waters GCT Premier mass spectrometer
or ESI on an Agilent Q‐TOF mass spectrometer. All
chemical formula confirmations were made with less
than 5 ppm difference between calculated and observed
masses. Purity determination by elemental analysis
(EA) was performed in duplicate on a Perkin Elmer
2400 CHN analyzer. Cyclic voltammetry experiments
were performed using an Autolab PGSTAT302
potentiostat in a temperature controlled, 3‐electrode
15‐mL cell. The working electrode was planar glassy
carbon, the quasi‐reference electrode was a silver wire,
and the counter electrode was a platinum wire. All
experiments were conducted under argon in approxi-
mately 1‐mM dried DMF solutions with approximately
0.5‐M (n‐Bu)4NBF4 supporting electrolyte internally ref-
erenced against the ferrocene/ferrocenium redox cou-
ple. A scan rate of 0.05 V·s‐1 was used unless
otherwise stated. The charge integration experiment of
Bn2(SCH3)ImBr was conducted using linear sweep
voltammetry between 1 and −1.9 V vs Ag/Ag+ in
2.5 mL of dried DMF having equal moles of both ana-
lyte and ferrocene (6.51 × 10−6 mol). The working elec-
trode was equilibrated at 0 V for 20 seconds before the
start of the sweep. Multiple scan rate experiments on
Bn2(SCH3)ImBr used the same stock solutions as for
FIGURE 4 Correlation diagram of calculated EA vs experimental
E(LUMO) for imidazolium triflates (top) and bromides (bottom)
strongly with the imidazolium, whereas bromide coordi-
nates more strongly and would have a greater influence on
the electronics of the imidazolium. These electrochemical
and computational data support the spectroscopic observa-
tions of Cremer et al on imidazolium anion effects.[30]
3 | CONCLUSIONS
To summarize, we have shown that electrochemical
reduction is facilitated by over 1 V through incorporation
of electron withdrawing groups at the 2‐position of
imidazolium salts. The electrochemical modularity is
even more pronounced given how few synthetic steps

8 of 15
HOGAN AND SUTHERLAND
charge integration (both analyte and ferrocene being
present in 6.51 × 10−6 mol), and working electrode
was equilibrated at 0 V for 10 seconds before measure-
ment. Full scans from 1.05 to −1.75 V vs Ag/Ag+ using
scan rates of 10, 20, 50, 100, 200, 500, and 1000 mV·s‐1
were collected. Differential pulse voltammetry was per-
formed using the same experimental setup as for CV
(above). The working electrode was conditioned at
1 V for 20 seconds, and the experiment was performed
from 1 to −1.9 V vs Ag/Ag+ with 1‐second intervals
between 0.05‐V steps. Tetrahydrofuran, DMF for
lithiations, and CH3CN were purchased from Sigma‐
Aldrich and dried over flame‐dried 3 Å molecular
sieves 24 hours prior to use. Benzyl bromide was pur-
chased from Sigma‐Aldrich, purified by redistillation
under reduced pressures, and stored away from light.
NBS was purchased from Sigma‐Aldrich, purified by
recrystallization from boiling water, and stored in a
vacuum desiccator. 35% hydrogen peroxide and 1‐
benzylimidazole 3a were purchased from Oakwood
Chemical. All other chemicals were purchased from
Sigma‐Aldrich and used as received. All round‐bot-
tomed flasks for reactions were oven‐dried for a mini-
mum of 24 hours prior to use. Technical grade silica
gel for flash column chromatography (40‐63 μm size)
was purchased from Sigma‐Aldrich and used without
modification.
and the combined organics were washed with brine and
then dried over anhydrous Na2SO4. Concentration under
reduced pressures yielded a viscous, clear yellow oil. This
was adsorbed to silica and loaded onto a 16‐cm‐tall × 4.5‐
cm‐wide silica column packed in 25% Et2O/hexanes.
Gradient elution first with 25% Et2O/hexanes (approxi-
mately 400 mL) eluted excess (CH3)2S2, then with 50%
Et2O/hexanes (approximately 2 L) eluted 1‐benzyl‐2‐
(methylsulfanyl)‐imidazole as a clear, light‐yellow liquid
1
(1.043 g, 80% yield): Rf (70% EtOAc/hexanes) = 0.40; H
NMR (400 MHz, CD3Cl) δ = 7.38‐7.27 (m, 3H), 7.16‐7.13
(m, 2H), 7.10 (d, J = 1.4 Hz, 1H), 6.93 (d, J = 1.4 Hz,
1H), 5.11 (s, 2H), 2.57 (s, 3H); 13C{1H} NMR (100 MHz,
CDCl3)
δ
=
143.2, 136.4, 129.7, 129.0,128.2,
127.4, 121.3, 50.1, 16.6; HRMS (EI, positive) calculated
m/z = 204.0721 [M]+, found m/z = 204.0725 [M]+; EA
calculated for C11H12N2S = 64.67% C, 5.92% H, 13.71% N
found = 64.29% C, 6.11% H, 13.99% N.
4.2.2 | 1‐Benzyl‐2‐(methylsulfinyl)‐imidaz-
ole 4a
This experimental was adapted from
a literature
procedure.[36] Into a 100‐mL RBF, a magnetic stir bar
and 1‐benzyl‐2‐(methylsulfanyl)‐imidazole (0.5223 g,
0.002557 mol, 1 eq.) were added. Glacial acetic acid
(50 mL) was added, and the mixture was stirred to disso-
lution at room temperature. The flask was capped with a
rubber septum pierced by a needle for pressure relief, then
thermalized to 50°C on an oil bath. Aqueous H2O2 (35%,
0.88 mL, 0.010 mol, 4 eq.) was added by syringe, dropwise
over 1 minute. The resulting clear light‐yellow solution
was allowed to stir for 4.5 hours. After this time, the solu-
tion had become clear and colorless. Saturated aqueous
Na2SO3 (5 mL) was added to quench excess H2O2, and
the solution was allowed to cool to room temperature. It
was transferred to a separatory funnel and brought to
pH 9 to 10 (by pH indicator paper) by portion‐wise addi-
tion of 5 M NaOH. Over the course of addition, the solu-
tion became slightly cloudy yellow and it was then
allowed to cool to room temperature. The basic solution
was extracted with EtOAc (8 × 15 mL); the organic
extracts were brine washed then dried over anhydrous
Na2SO4. Concentration under reduced pressures yielded
a viscous, light‐yellow oil. This was adsorbed to silica
and loaded onto a 5‐cm‐tall × 2.5‐cm‐wide silica column
packed in 50% EtOAc/hexanes. Gradient elution first with
50% EtOAc/hexanes (approximately 200 mL), then
with 70% EtOAc/hexanes (approximately 600 mL) eluted
1‐benzyl‐2‐(methylsulfinyl)‐imidazole as a clear, colorless
oil, which solidified on standing to a white, waxy solid
(0.4112 g, 73%): Rf (70% EtOAc/hexanes) = 0.10; mp
4.2 | Synthesis
4.2.1 | 1‐Benzyl‐2‐(methylsulfanyl)‐imid-
azole 3b
This experimental was adapted from a literature proce-
dure.[60] Into an oven‐dried 250‐mL RBF, 1‐benzyl‐imid-
azole (1.0058 g, 0.0063574 mol, 1 eq.) and an oven‐dried
magnetic stir bar were added. THF (100 mL) was added
and the flask was capped with a rubber septum. The mix-
ture was stirred to dissolution while the flask headspace
was flushed with N2. The flask was submerged into an
acetone/CO2(s) bath and thermalized to −78°C. n‐BuLi
(1.54 M, 4.14 mL, 0.00638 mol, 1 eq.) was added dropwise
by syringe over 10 minutes. The resulting intense cherry‐
red and clear solution was allowed to stir for 30 minutes
at −78°C. After this time, (CH3)2S2 (1.13 mL,
0.0127 mol, 2 eq.) was added at −78°C over 5 minutes.
The solution turned light peach‐yellow and was allowed
to warm to room temperature, then stirred for a further
2 hours. The resulting cloudy deep‐yellow solution was
diluted with saturated aqueous NaHCO3 (50 mL) and
EtOAc (30 mL). The biphase was transferred to a
separatory funnel, and the layers were separated. The
aqueous layer was extracted with EtOAc (3 × 30 mL),
1
(70% EtOAc/hexanes) = 73‐76°C; H NMR (400 MHz,

HOGAN AND SUTHERLAND
9 of 15
CD3CN) δ = 7.40‐7.30 (m, 3H), 7.28‐7.24 (m, 2H), 7.23 (d,
J = 1.0 Hz, 1H), 7.15 (d, J = 1.0 Hz, 1H), 5.46 (s, 1H), 2.95
(s, 3H); 13C{1H} NMR (100 MHz, CD3CN) δ = 147.7, 137.7,
130.5, 129.9, 129.2, 128.5, 125.2, 50.8, 39.1;
HRMS (EI, positive) calculated m/z = 220.0670 [M]+,
4.2.4 | 1‐Benzyl‐2‐bromo‐imidazole 3a
This experimental was adapted from a literature proce-
dure.[34] Into an oven‐dried 100‐mL RBF, 1‐benzyl‐imid-
azole (0.5004 g, 0.003182 mol, 1 eq.) and an oven‐dried
magnetic stir bar were added. THF (50 mL) was added,
and the flask was capped with a rubber septum. The mix-
ture was stirred to dissolution while the flask headspace
was flushed with N2. The flask was submerged into an
acetone/CO2(s) bath and thermalized to −78°C. n‐BuLi
(1.31 M, 2.43 mL, 0.00318 mol, 1 eq.) was added dropwise
by syringe over 10 minutes. The resulting intense cherry‐
red and clear solution was allowed to stir for 30 minutes at
−78°C. Separately, an NBS/THF solution was prepared
under N2 by adding THF (10 mL) to NBS (0.5289 g,
0.002972 mol, 0.95 eq.) and agitating to dissolution. This
solution was added dropwise to the lithiated solution at
−78°C over 5 minutes. The solution turned blood‐red,
dark green‐black, then orange‐brown. It was allowed to
warm to room temperature, then stirred for a further
2 hours, over which time the solution turned red‐brown
and opaque. The mixture was diluted with saturated
aqueous NaHCO3 (15 mL) and EtOAc (15 mL). The
biphase was transferred to a separatory funnel, and the
layers were separated. The aqueous layer was extracted
with EtOAc (3 × 15 mL), and the combined organics were
washed with brine and then dried over anhydrous
Na2SO4. Concentration under reduced pressures yielded
a viscous, red‐brown oil. This was adsorbed to silica and
loaded onto a 15‐cm‐tall × 4.5‐cm‐wide silica column
packed in 20% EtOAc/hexanes. Elution with 20%
EtOAc/hexanes (approximately 1.1 L) eluted 1‐benzyl‐2‐
bromo‐imidazole as a clear, light‐yellow liquid (0.3467 g,
49% yield): Rf (50% EtOAc/hexanes) = 0.73; 1H NMR
(400 MHz, CDCl3) δ = 7.39‐7.30 (m, 3H), 7.18‐7.14 (m,
2H), 7.04 (d, J = 1.3 Hz, 1H), 6.95 (d, J = 1.3 Hz, 1H),
5.11 (s, 2H); 13C{1H} NMR (100 MHz, CDCl3) δ = 135.6,
130.4, 129.1, 128.4, 127.4, 122.3, 120.1, 51.4; HRMS (EI,
positive) calculated m/z = 235.9949 [M]+, 237.9929
[M + 2]+ found m/z = 235.9957 [M]+, 237.9939 [M + 2]
+; EA calculated for C10H9N2Br = 50.66% C, 3.83% H,
11.82% N found = 50.33% C, 3.70 % H, 11.83% N.
found m/z
=
220.0671 [M]+; EA calculated for
59.98% C, 5.49% H, 12.72%
C11H12ON2S
=
N
found = 59.96% C, 5.39% H, 12.70% N.
4.2.3 | 1‐Benzyl‐2‐(methylsulfonyl)‐imid-
azole 4b
This experimental was adapted from a literature proce-
dure.[36] Into
a
100 mL RBF, 1‐benzyl‐(2‐
methylsulfanyl)‐imidazole (0.5250 g, 0.002570 mol, 1 eq.)
and a magnetic stir bar were added. Glacial acetic acid
(50 mL) was added, and the mixture was stirred to disso-
lution at room temperature. The flask was capped with a
rubber septum pierced with a needle for pressure relief,
then it was allowed to thermalize to 90°C on an oil bath.
Aqueous H2O2 (35%, 0.88 mL, 0.010 mol, 4 eq.) was added
by syringe, dropwise over 1 minute. The resulting clear
light‐yellow solution was allowed to stir for 5 hours. After
this time, the solution had become clear and colorless.
Saturated aqueous Na2SO3 (5 mL) was added to quench
excess H2O2, and the solution was allowed to cool to room
temperature. It was transferred to a separatory funnel and
brought to pH 9 to 10 (by pH indicator paper) by portion‐
wise addition of 5 M NaOH. Over the course of addition,
the solution became increasingly dull, milky yellow, and
it was then allowed to cool to room temperature. The
basic solution was extracted with EtOAc (8 × 15 mL);
the organic extracts were brine washed then dried over
anhydrous Na2SO4. Concentration under reduced
pressured yielded a viscous, light‐yellow oil. This was
adsorbed to silica and loaded onto a 5‐cm‐tall × 2.5‐cm‐
wide silica column packed in 30% EtOAc/hexanes. Gradi-
ent elution first with 30% EtOAc/hexanes (approximately
120 mL), then with 50% EtOAc/hexanes (approximately
200 mL) eluted 1‐benzyl‐2‐(methylsulfonyl)‐imidazole as
a clear, colorless oil, which solidified on standing to an
off‐white waxy solid (0.4344 g, 72% yield): Rf (70%
EtOAc/hexanes)
=
0.50;
mp
(50%
EtOAc/
4.2.5 | 1‐Benzyl‐2‐formyl‐imidazole 3c
hexanes) = 36‐39°C; 1H NMR (400 MHz, CD3CN)
δ = 7.40‐7.30 (m, 3H), 7.27 (d, J = 1.1 Hz, 1H), 7.26‐7.22
(m, 2H), 7.15 (d, J = 1.1 Hz, 1H), 5.55 (s, 2H), 3.16(s,
3H); 13C{1H} NMR (100 MHz, CD3CN) δ = 143.5, 137.6,
130.0, 129.8, 129.2, 128.4, 126.3, 51.9, 43.9;
HRMS (EI, positive) calculated m/z = 236.0619 [M]+,
This experimental was adapted from a literature proce-
dure.[32] Into an oven‐dried 100‐mL RBF, 1‐benzyl‐imid-
azole (0.5028 g, 0.003178 mol, 1 eq.) and an oven‐dried
magnetic stir bar were added. THF (50 mL) was added,
and the flask was capped with a rubber septum. The
mixture was stirred to dissolution while the flask head-
space was flushed with N2. The flask was submerged
into an acetone/CO2(s) bath and thermalized to −78°C.
found m/z
=
236.0616 [M]+; EA calculated for
55.92% C, 5.12% H, 11.86%
C11H12O2N2S
=
N
found = 55.79% C, 5.07% H, 12.46% N.

10 of 15
HOGAN AND SUTHERLAND
n‐BuLi (1.31 M, 2.43 mL, 0.00318 mol, 1 eq.) was added
dropwise by syringe over 10 minutes. The resulting
intense cherry‐red and clear solution was allowed to stir
for 30 minutes at −78°C. After this time, DMF
(0.49 mL, 0.0063 mol, 2 eq.) was added at −78°C over
5 minutes. The solution turned cherry pink and was
allowed to warm to room temperature, then stirred for
a further 2 hours. The resulting light‐yellow solution
was diluted with saturated aqueous NH4Cl (15 mL)
and EtOAc (15 mL). The biphase was transferred to a
separatory funnel and the layers were separated. The
aqueous layer was extracted with EtOAc (3 × 15 mL),
and the combined organics were washed with brine
and then dried over anhydrous Na2SO4. Concentration
under reduced pressures yielded a viscous, clear yellow
oil. This was adsorbed to silica and loaded onto a 6‐
cm‐tall × 2.5‐cm‐wide silica column packed in 30%
EtOAc/hexanes. Elution with 30% EtOAc/hexanes
(approximately 500 mL) eluted 1‐benzyl‐2‐formyl‐imid-
azole as a clear, light‐yellow liquid (0.5074 g, 86% yield):
dibenzylimidazolium bromide as a waxy light‐yellow
solid (12.011 g, 93% yield). It can be recrystallized as an
off‐white crystalline solid from boiling 1:1 THF:acetone;
mp (1:1 THF:acetone) softens at 73°C to 75°C, melts at
82°C to 85°C; 1H NMR (400 MHz, CDCl3) δ = 11.05
(s, 1H), 7.47‐7.44 (m, 4H), 7.43‐7.38 (m, 6H), 7.13
(d, J = 1.6 Hz, 2H), 5.56 (s, 4H); 13C{1H} NMR (100 MHz,
CDCl3) δ = 137.7, 132.7, 129.8, 129.7, 129.2, 121.7,
53.8; HRMS (ESI, positive) calculated m/z = 249.1386
[M‐Br]+, found m/z = 249.1388 [M‐Br]+.
4.3 | General procedure for small‐scale
preparation of imidazolium triflates
This procedure is suitable for preparing small‐scale sam-
ples of imidazolium triflates, concentrated enough for
1H NMR and 13C NMR analysis. The desired imidazolium
bromide (approximately 3 × 10−5 mol, 1 eq.) was weighed
into a ½ dram screw‐cap glass vial. CDCl3 (0.75 mL) was
added by syringe, and the mixture was sonicated to disso-
lution/dispersion. AgOTf (approximately 3.3 × 10−5 mol)
was added in one portion; the cap was tightened and the
mixture was sonicated at room temperature for
10 minutes. The resulting milky pale‐yellow suspension
was filtered through a Pasteur pipette tightly stuffed with
a small plug of cotton/glass wool, and the clear colorless
filtrate was eluted directly into an NMR tube for analysis.
Rf (50% EtOAc/hexanes)
= 0.72; δ =
1H NMR
(400 MHz, CDCl3) δ = 9.97 (“apparent d,” 1H), 7.49‐
7.43 (m, 3H), 7.39 (s, 1H), 7.34‐7.31 (m, 2H), 5.74 (s,
2H); 13C{1H} NMR (100 MHz, CDCl3) δ = 182.4, 143.5,
135.9, 132.0, 129.1, 128.5, 127.9, 126.4, 51.1; HRMS (EI,
positive) calculated m/z
m/z = 186.0795 [M]+.
=
186.0793 [M]+, found
4.2.6 | 1,3‐(Dibenzyl)imidazolium bromide
Bn2(H)ImBr
4.3.1 | 1,3‐(Dibenzyl)imidazolium triflate
This experimental was adapted from a literature proce-
dure.[29] Into an oven‐dried 500‐mL RBF, imidazole
(2.6698 g, 0.039216 mol, 1 eq.), oven‐dried anhydrous
K2CO3 (8.1389 g, 0.058888 mol, 1.5 eq.), and a large
oven‐dried magnetic stir bar were added. CH3CN
(200 mL) were added, a Drierite drying tube was con-
nected to the mouth of the flask and the resulting mix-
ture was stirred for 15 minutes at room temperature to
effect dissolution of the imidazole. Benzyl bromide
(9.32 mL, 0.0785 mol, 2 eq.) was added dropwise by
syringe over 10 minutes, and the cloudy white mixture
was stirred at room temperature for 48 hours. After this
time, the resulting light yellow and turbid mixture was
gravity filtered through filter paper, and the filter cake
was washed with several small portions of CH3CN. The
collected filtrate was concentrated under reduced pres-
sures, yielding a viscous, clear light‐yellow oil, which
solidified upon standing for several days in the fridge.
The solid was transferred to a Büchner funnel and
washed with diethyl ether (approximately 10 mL) to
remove remaining benzyl bromide, then dried in vacuo.
This process was repeated a total of 7 times to yield 1,3‐
Bn2(H)ImOTf
This procedure is suitable for preparing macroscopic
quantities of imidazolium triflates because of the ease of
work‐up and scalability. Into an oven‐dried 5‐mL RBF,
1,3‐(dibenzyl)imidazolium
bromide
(0.3224
g,
9.789 × 10−4 mol, 1 eq.) and a small oven‐dried magnetic
stir bar were added. CH3CN (3 mL) was added, and the
flask was capped with a rubber septum. The flask head-
space was flushed with N2 and the mixture was stirred
to dissolution at room temperature. Methyl triflate
(0.11 mL, 0.0010 mol, 1 eq.) was added by syringe causing
the solution to change from colorless to golden‐yellow.
The solution was stirred at room temperature for 18 hours.
After this time, the solution was concentrated under
reduced pressures, reconstituted with CH2Cl2 (10 mL),
and partially decolorized by boiling with type‐A activated
carbon. Removal of the solvent yielded 1,3‐(dibenzyl)
imidazolium triflate as a viscous yellow liquid. 1H
NMR (400 MHz, CDCl3) δ = 9.60 (t, J = 1.6 Hz, 1H),
7.41‐7.32 (m, 10H), 7.16 (d, J = 1.6 Hz, 2H), 5.36 (s, 4H);
DEPT‐Q 13C{1H} NMR (100 MHz, CDCl3) δ = 136.64

HOGAN AND SUTHERLAND
11 of 15
(+), 132.66 (−), 129.75 (+), 129.65 (+), 129.12 (+), 122.11
(+), 53.73 (−).
under
reduced
pressures,
reconstituted
with
CH2Cl2 (10 mL) and partially decolorized by boiling with
type‐A activated carbon. Removal of the solvent yielded
1,3‐(dibenzyl)‐2‐methylimidazolium triflate as a viscous
amber‐yellow liquid. 1H NMR (400 MHz, CDCl3)
δ = 7.43‐7.34 (m, 6H), 7.26‐7.23 (m, 4H), 7.14 (s, 2H),
5.29 (s, 4H), 2.64 (s, 3H); DEPT‐Q 13C{1H} NMR (100 MHz,
CDCl3) δ = 144.72 (−), 132.56 (−), 129.57 (+), 129.37 (+),
128.29 (+), 121.54 (+), 52.45 (−), 10.69 (+).
4.3.2 | 1,3‐(Dibenzyl)‐2‐methylimidazolium
bromide Bn2(CH3)ImBr
This experimental was adapted from
a literature
procedure.[29] Into an oven‐dried 50‐mL RBF, 2‐
methylimidazole (0.3226 g, 0.003929 mol, 1 eq.), oven‐
dried anhydrous K2CO3 (0.8167 g, 0.005909 mol, 1.5 eq.),
and a small oven‐dried magnetic stir bar were added.
CH3CN (20 mL) were added; a Drierite drying tube was
connected to the mouth of the flask and the resulting mix-
ture was stirred for 15 minutes at room temperature to
effect dissolution of the 2‐methylimidazole. Benzyl bro-
mide (0.93 mL, 0.0078 mol, 2 eq.) was added dropwise
by syringe over 3 minutes, and the cloudy white mixture
was stirred at room temperature for 48 hours. After this
time, the resulting light yellow and turbid mixture was
concentrated under reduced pressures to yield a caked
white solid, which was then reconstituted with CH2Cl2
(20 mL) and H2O (50 mL). The layers were separated in
a separatory funnel, the aqueous layer was extracted with
CH2Cl2 (3 × 0 mL), and the combined extracts were dried
over anhydrous Na2SO4. Concentration under reduced
pressures produced a white powder, which was suction
filtered on filter paper, washed with excess diethyl ether,
and dried in vacuo to yield 1,3‐(dibenzyl)‐2‐
methylimidazolium bromide as a white granulated solid
(0.6697 g, 50% yield). It can be recrystallized as a white
crystalline solid from boiling 1:3 acetone: CH3CN: mp
4.3.4 | 1,3‐(Dibenzyl)‐2‐phenylimidazolium
bromide Bn2(Ph)ImBr
This experimental was adapted from
a literature
procedure.[29] Into an oven‐dried 50‐mL RBF, 2‐
phenylimidazole (0.5631 g, 0.003906 mol, 1 eq.) and an
oven‐dried magnetic stir bar were added. Oven‐dried
anhydrous K2CO3 (0.8112 g, 0.005869 mol, 1.5 eq.) was
added followed by CH3CN, and the mixture was stirred
at room temperature to dissolve all 2‐phenylimidazole.
Benzyl bromide (0.93 mL, 0.0078 mol, 2 eq.) was added
by syringe and the flask was equipped with a Drierite dry-
ing tube. The light‐yellow mixture was stirred at room
temperature for 72 hours. The resulting cloudy white mix-
ture was concentrated under reduced pressures to yield a
solid yellow residue. This was reconstituted with deion-
ized H2O (50 mL) and CH2Cl2 (30 mL). The mixture was
transferred to a separatory funnel, and the layers were
separated. The aqueous layer was extracted with CH2Cl2
(3 × 10 mL); the combined organics were dried over anhy-
drous Na2SO4 and concentrated under reduced pressures
to yield a viscous yellow oil. This was purified by boiling
a CH2Cl2 solution with type‐A activated carbon and again
concentrating the solution producing 1,3‐(dibenzyl)
imidazolium bromide as a light‐yellow viscous liquid
(1.3773 g, 88% yield). Spectroscopic characterization
matched literature reports.[24]
1
(1:3 acetone:CH3CN) = 222‐226°C; H NMR (400 MHz,
CDCl3) δ = 7.44‐7.37 (m, 5H), 7.36‐7.33 (m, 5H), 5.50 (s,
4H), 2.85 (s, 3H); 13C{1H} NMR (100 MHz, (CD3)2SO)
δ = 144.5, 134.4, 129.0, 128.5, 127.8, 122.0, 50.8, 9.8; HRMS
(ESI, positive) calculated m/z = 263.1543 [M‐Br]+, found
m/z = 263.1545 [M‐Br]+.
4.3.3 | 1,3‐(Dibenzyl)‐2‐methylimidazolium
triflate Bn2(CH3)ImOTf
4.3.5 | 1,3‐(Dibenzyl)‐2‐phenylimidazolium
triflate Bn2(Ph)ImOTf
This procedure is suitable for preparing macroscopic
quantities of imidazolium triflates because of the ease of
work‐up and scalability. Into an oven‐dried 25‐mL RBF,
1,3‐(dibenzyl)‐2‐methylimidazolium bromide (0.3467 g,
0.001010 mol, 1 eq.) and a small oven‐dried magnetic stir
bar were added. CH3CN (15 mL) was added, and the flask
was capped with a rubber septum. The flask headspace
was flushed with N2, and the suspension was stirred at
room temperature. Methyl triflate (0.11 mL, 0.0010 mol,
1 eq.) was added by syringe forming a clear light‐yellow
solution, which was stirred at room temperature for
18 hours. After this time, the solution was concentrated
This procedure is suitable for preparing macroscopic
quantities of imidazolium triflates because of the ease of
work‐up and scalability. Into an oven‐dried 10‐mL RBF,
1,3‐(dibenzyl)‐2‐methylimidazolium bromide (0.5665 g,
0.001398 mol, 1 eq.) and a small oven‐dried magnetic stir
bar were added. CH3CN (4 mL) was added, and the flask
was capped with a rubber septum. The flask headspace
was flushed with N2, and the mixture was stirred to disso-
lution at room temperature. Methyl triflate (0.14 mL,
0.0014 mol, 1 eq.) was added by syringe forming a clear
golden‐orange solution, which was stirred at room tem-
perature for 18 hours. After this time, the solution was

12 of 15
HOGAN AND SUTHERLAND
concentrated under reduced pressures, reconstituted with
CH2Cl2 (10 mL), and partially decolorized by boiling with
type‐A activated carbon. Removal of the solvent yielded
1,3‐(dibenzyl)‐2‐phenylimidazolium triflate as a viscous
dark amber liquid, which formed clear light‐brown crys-
work‐up and scalability. Into an oven‐dried 10 mL RBF,
1,3‐(dibenzyl)‐2‐(methylsulfanyl)imidazolium
bromide
(0.4158 g, 0.001108 mol, 1 eq.) and a small oven‐dried
magnetic stir bar were added. CH3CN (3 mL) was added,
and the flask was capped with a rubber septum. The flask
headspace was flushed with N2, and the mixture was
stirred to dissolution at room temperature. Methyl triflate
(0.12 mL, 0.0011 mol, 1 eq.) was added by syringe forming
a clear light‐yellow solution, which was stirred at room
temperature for 18 hours. After this time, the solution
was concentrated under reduced pressures, reconstituted
with CH2Cl2 (10 mL), and partially decolorized by boiling
with type‐A activated carbon. Removal of the solvent
1
tals on standing. H NMR (400 MHz, CDCl3) δ = 7.69
(m, 1H), 7.61 (m, 2H), 7.56‐7.51 (m, 2H), 7.46 (s, 2H),
7.37‐7.30 (m, 6H), 7.14‐7.07 (m, 4H), 5.18 (s, 4H); DEPT‐
Q
13C{1H} NMR (100 MHz, CDCl3) δ = 145.05 (−),
133.21 (−), 133.08 (+), 130.71 (+), 130.09 (+),
129.17 (+), 129.10 (+), 128.30 (+), 122.69 (+), 121.03
(−), 52.78 (−).
yielded
1,3‐(dibenzyl)‐2‐(methylsulfanyl)imidazolium
4.3.6 | 1,3‐(Dibenzyl)‐2‐(methylsulfanyl)
1
triflate as a viscous amber liquid. H NMR (400 MHz,
CDCl3) δ = 7.49 (s, 2H), 7.44‐7.30 (m, 10H), 5.53 (s, 4H),
2.34 (s, 3H); DEPT‐Q 13C{1H} NMR (100 MHz, CDCl3)
δ = 131.71 (−), 129.77 (+), 129.61 (+), 128.94 (+), 124.67
(+), 54.64 (−); uDEFT 13C{1H} NMR (100 MHz, CDCl3)
δ = 131.71, 129.78, 129.63, 128.94, 124.68, 120.60, 54.66.
imidazolium bromide Bn2(SCH3)ImBr
Into an oven‐dried 25‐mL RBF, 1‐benzyl‐2‐
(methylsulfanyl)imidazole (0.2518 g, 0.001175 mol, 1 eq.)
and a small oven‐dried magnetic stir bar were added.
CH3CN (12.5 mL) was added, and the flask was capped
with a rubber septum. The mixture was stirred to dissolu-
tion at room temperature while the flask headspace was
flushed with N2 to prevent aerial oxidation of the starting
material. The solution was thermalized to 30°C on an oil
bath, and benzyl bromide (0.14 mL, 0.0012 mol, 1 eq.)
was added by syringe. The solution was allowed to heat
and stir for 18 days. After this time, the light‐yellow and
clear reaction mixture was concentrated under reduced
pressures to yield a yellow oil. This was put under high‐
vacuum for 16 hours to produce a fluffy light‐yellow resi-
due. Diethyl ether (25 mL) was added to fill the flask; the
residue was manually agitated with a spatula and allowed
to settle overnight in the fridge. The mixture was rapidly
suction filtered over filter paper, and the isolated solid
was quickly transferred to a small Erlenmeyer flask (if
the filtration is not completed quickly then the product
acquires a caramel‐like consistency which is difficult to
handle). Trituration with boiling 1:1 EtOAc:acetone
(5 mL), suction filtration over filter paper, and drying in
4.3.8 | 1,3‐(Dibenzyl)‐2‐formylimidazolium
bromide Bn2(CHO)ImBr
Into an oven‐dried 35 mL RBF, a small oven‐dried mag-
netic stir bar and 1‐benzyl‐2‐formylimidazole (0.5143 g,
0.002762 g, 1 eq.) were added. A rubber septum was
attached to the flask, and the headspace was purged with
N2 to prevent aerial oxidation. Benzyl bromide (6.6 mL,
0.056 mol, 20 eq.) was added by syringe; the clear colorless
solution was thermalized to 50°C on an oil bath and then
stirred for 24 hours. The resulting cloudy off‐white mix-
ture was allowed to cool to room temperature then diluted
with Et2O (15 mL) to precipitate a fluffy white solid. The
mixture was suction filtered over filter paper, washed
with excess Et2O and dried in vacuo to yield 1,3‐
(dibenzyl)‐2‐formylimidazolium bromide as a moisture‐
sensitive, light‐beige chalky solid (0.7585 g, 77% yield). It
can be recrystallized as fine, off‐white needles from boiling
CH3CN: mp (CH3CN) = 180‐182°C (decomp and gas
vacuo
yielded
1,3‐(dibenzyl)‐2‐(methylsulfanyl)
1
imidazolium bromide as an off‐white powder (0.1685 g,
38% yield): mp (1:1 EtOAc:acetone) = 124‐128°C; 1H
NMR (400 MHz, CDCl3) δ = 7.76 (s, 2H), 7.44‐7.38 (m,
10H), 5.69 (s, 4H), 2.45 (s, 3H); 13C{1H} NMR (100 MHz,
CDCl3) δ = 140.4, 133.1, 129.7, 129.6, 128.7, 125.1, 53.9,
19.2; HRMS (ESI, positive) calculated m/z = 295.1263
[M‐Br]+, found m/z = 295.1276 [M‐Br]+.
evolved); H NMR (400 MHz, CD3CN) δ = 10.14 (s, 1H),
7.61 (s, 2H), 7.49‐7.39 (m, 10H), 5.76 (s, 4H); DEPT‐Q
13C{1H} NMR (100 MHz, CD3CN) δ = 176.0 (−), 134.2
(+), 130.2 (−), 130.2 (−), 130.0 (−), 129.8 (−), 129.6 (−),
129.4 (−), 126.2 (−), 123.1 (−), 53.9 (+), 53.1 (+); HRMS
(ESI, positive) calculated for aldehyde m/z = 277.1335
[M‐Br]+, found for aldehyde m/z = 277.1337 [M‐Br]+;
HRMS (ESI, positive) calculated for hydrate
m/z
=
295.1447 [M‐Br]+, found for hydrate m/
4.3.7 | 1,3‐(Dibenzyl)‐2‐(methylsulfanyl)
imidazolium triflate Bn2(SCH3)ImOTf
z = 295.1438 [M‐Br]+. *A 13C NMR spectrum could not be
obtained showing all carbons in the compound, even
DEPT‐Q with 14 000 scans over 16 hours. UDEFT 13C{1H}
NMR with 1000 scans revealed 2 more signals at δ = 135.3
This procedure is suitable for preparing macroscopic
quantities of imidazolium triflates because of the ease of

HOGAN AND SUTHERLAND
13 of 15
and 83.6. This difficulty is likely due to formation of the
hydrate, which slowly consumed the aldehyde over the
duration of the acquisitions. It is likely that the signals at
δ = 135.3, 130.0, 129.8, 129.4, 123.1, 83.6, and 53.1 belong
to the hydrate due to their proportionally lower intensities.
However, the C‐2 carbons for both aldehyde and hydrate
were never observed. When 1H NMR was acquired in
CD3CN containing H2O and the tube was allowed to sit
for 4 days, a new set of proton resonances grew at the
expense of an old set (Supporting Information). Hydrate
small oven‐dried magnetic stir bar were added. A rubber
septum was attached and benzyl bromide (5.5 mL,
0.046 mol, 20 eq.) was added by syringe. The clear color-
less solution was thermalized to 50°C on an oil bath and
stirred for 24 hours. After this time, the cloudy off‐white
mixture was allowed to cool to room temperature, and
Et2O (15 mL) were added to precipitate a fluffy white
solid. The mixture was suction filtered through filter
paper, washed with excess Et2O, and dried in vacuo to
yield 1,3‐dibenzyl‐2‐bromoimidazolium bromide as a
white chalky powder (0.8288 g, 88% yield). It can be
recrystallized as fine white needles from boiling CH3CN:
1
formation is supported by recording H NMR in CD3CN
before and after adding D2O and observing the growth/dis-
appearance of the same 2 sets of resonances (Supporting
Information). HR MS observations of a peak with m/z cor-
responding to the hydrate further solidified this assignment.
1
mp (CH3CN) = 175‐180°C; H NMR (400 MHz, CD3CN)
δ = 7.63 (s, 2H), 7.47‐7.40 (m, 6H), 7.40‐7.34 (m, 4H),
5.38 (s, 4H); 13C{1H} NMR (100 MHz, CD3CN) δ = 133.9,
130.2, 130.2, 129.4, 125.4, 123.8, 54.7; HRMS (ESI, posi-
tive) calculated m/z = 327.0491 [M‐Br]+, found m/
z = 327.0506 [M‐Br]+.
4.3.9 | 1,3‐(Dibenzyl)‐2‐formylimidazolium
triflate Bn2(CHO)ImOTf
This procedure is suitable for preparing macroscopic
quantities of imidazolium triflates because of the ease of
work‐up and scalability. Into an oven‐dried 10‐mL RBF,
1,3‐(dibenzyl)‐2‐formylimidazolium bromide (0.3907 g,
0.001094 mol, 1 eq.) and a small oven‐dried magnetic stir
bar were added. CH3CN (6 mL) was added, and the flask
was capped with a rubber septum. The flask headspace
was flushed with N2, and the mixture was stirred to disso-
lution at room temperature. Methyl triflate (0.12 mL,
0.0011 mol, 1 eq.) was added by syringe forming a clear
light‐yellow solution, which was stirred at room tempera-
ture for 18 hours. After this time, the solution was concen-
trated under reduced pressures, reconstituted with CH2Cl2
(10 mL) and partially decolorized by boiling with type‐A
activated carbon. Removal of the solvent yielded 1,3‐
4.3.11 | 1,3‐(Dibenzyl)‐2‐bromoimidazolium
triflate Bn2(Br)ImOTf
This procedure is suitable for preparing macroscopic
quantities of imidazolium triflates because of the ease of
work‐up and scalability. Into an oven‐dried 10‐mL RBF,
1,3‐(dibenzyl)‐2‐bromoimidazolium bromide (0.4475 g,
0.001096 mol, 1 eq.) and a small oven‐dried magnetic stir
bar were added. CH3CN (6 mL) was added, and the flask
was capped with a rubber septum. The flask headspace
was flushed with N2 and the suspension was stirred at
room temperature. Methyl triflate (0.12 mL, 0.0011 mol,
1 eq.) was added by syringe forming a clear light‐yellow
solution, which was stirred at room temperature for
18 hours. After this time, the solution was concentrated
under reduced pressures, reconstituted in CH2Cl2
(10 mL) and partially decolorized by boiling with type‐A
activated carbon. Removal of the solvent yielded 1,3‐
(dibenzyl)‐2‐formylimidazolium triflate as
a viscous
amber‐orange liquid. 1H NMR (400 MHz, CDCl3)
δ = 10.13 (s, 1H), 7.37 (m, 24H), 6.87 (s, 2H), 6.79 (s, 1H),
6.59 (s, 2H), 5.74 (s, 4H), 5.53 (s, 4H). This spectrum con-
tains 1:1 of the aldehyde and its hydrate, by analogy to
the spectrum of 1,3‐(dibenzyl)‐2‐formylimidazolium bro-
mide; DEPT‐Q 13C{1H} NMR (100 MHz, CDCl3)
δ = 174.58 (+), 132.69 (−), 132.18 (−), 129.83 (+), 129.65
(+), 129.55 (+), 129.49 (+), 129.15 (+), 129.11 (+), 128.80
(+), 124.90 (+), 121.38 (+), 83.60 (+), 53.81 (−), 53.03 (−).
(dibenzyl)‐2‐bromoimidazolium triflate as
a viscous
amber‐orange liquid. 1H NMR (400 MHz, CDCl3)
δ = 7.51 (s, 2H), 7.44‐7.32 (m, 10H), 5.37 (s, 4H); DEPT‐
Q
13C{1H} NMR (100 MHz, CDCl3) δ = 131.71 (−),
129.77 (+), 129.61 (+), 128.94 (+), 124.67 (+), 54.64 (−);
uDEFT 13C{1H} NMR (100 MHz, CDCl3) δ = 131.71,
129.78, 129.63, 128.94, 124.68, 120.60, 54.66.
13
*A C NMR spectrum containing all carbons could not
be collected, again because of hydrate formation. The miss-
ing carbons likely are C‐2 of both aldehyde and hydrate.
ACKNOWLEDGMENTS
4.3.10 | 1,3‐(Dibenzyl)‐2‐bromoimidazolium
The authors thank the Natural Sciences and Engineering
Research Council (NSERC) of Canada Discovery Grant
for funding, and D.T.H. thanks both Alberta Innovates
and NSERC PGS program for scholarships. D.T.H. is
bromide Bn2(Br)ImBr
Into an oven‐dried 25‐mL RBF, 1‐benzyl‐2‐
bromoimidazole (0.5513 g, 0.002325 mol, 1 eq.) and a

14 of 15
HOGAN AND SUTHERLAND
[24] H. V. Huynh, Y. Han, R. Jothibasu, J. A. Yang, Organometallics
2009, 28, 5395.
grateful to Mr Wade White and Mrs Michelle Thibault for
mass spectral analysis as well as Mr Jian Jun Li for ele-
mental analysis.
[25] S. T. Handy, M. Okello, J. Org. Chem. 2005, 70, 1915.
[26] N. Kumar, R. Jain, J. Heterocycl. Chem. 2012, 49, 370.
[27] K. Periyapperuma, Y. Zhang, D. R. Macfarlane, M. Forsyth, C.
ORCID
Pozo‐Gonzalo, P. C. Howlett, ChemElectroChem 2017, 1051.
David T. Hogan http://orcid.org/0000-0002-6494-6300
Todd C. Sutherland http://orcid.org/0000-0002-9321-7633
[28] D. Zhang, Q. Liu, X. Shi, Y. Li, J. Power Sources 2012, 203, 201.
[29] S. Patil, J. Claffey, A. Deally, M. Hogan, B. Gleeson, L. M. M.
Méndez, H. Müller‐Bunz, F. Paradisi, M. Tacke, Eur. J. Inorg.
Chem. 2010, 1020.
REFERENCES
[30] T. Cremer, C. Kolbeck, K. R. J. Lovelock, N. Paape, R. Wölfel, P.
S. Schulz, P. Wasserscheid, H. Weber, J. Thar, B. Kirchner,
et al., Chem. ‐ A Eur. J. 2010, 16, 9018.
[1] O. Edenhoffer, K. Seyboth, F. Creutzig, S. Schlomer, Annu. Rev.
Environ. Resour. 2013, 38, 169.
[2] S. Weitemeyer, D. Kleinhans, T. Vogt, C. Agert, Renew. Energy
2015, 75, 14.
[31] N. V. Ignat'ev, P. Barthen, A. Kucheryna, H. Willner, P. Sartori,
Molecules 2012, 17, 5319.
[3] G. L. Soloveichik, Chem. Rev. 2015, 115, 11533.
[32] L. I. Kruse, C. Kaiser, W. W. De, J. A. Finkelstein, J. S. Frazee,
E. L. Hilbert, S. T. Ross, K. E. Flaim, J. L. Sawyer, J. Med. Chem.
1990, 33, 781.
[4] M. Skyllas‐Kazacos, L. Cao, M. Kazacos, N. Kausar, A. Mousa,
ChemSusChem 2016, 9, 1521.
[33] A. R. Katritzky, G. W. Rewcastle, W.‐Q. Fan, J. Org. Chem. 1988,
53, 5685.
[5] F. Pan, Q. Wang, Molecules 2015, 20, 20499.
[6] J. Noack, N. Roznyatovskaya, T. Herr, P. Fischer, Angew.
Chemie ‐ Int. Ed. 2015, 54, 9776.
[34] K. Kirk, J. Org. Chem. 1978, 43, 42.
[35] C. Bakhtiar, E. H. Smith, J. Chem. Soc. Perkin Trans. 1 1994,
[7] J. Winsberg, T. Hagemann, T. Janoschka, M. D. Hager, U. S.
239.
Schubert, Angew. Chemie ‐ Int. Ed. 2017, 56, 686.
[36] F. Zani, P. Mazza, S. Benvenuti, F. Severi, L. Malmusi, G.
[8] Y. Zhao, Y. Ding, Y. Li, L. Peng, H. R. Byon, J. B. Goodenough,
Vampa, L. Antolini, Eur. J. Med. Chem. 1995, 30, 729.
G. Yu, Chem. Soc. Rev. 2015, 44, 7968.
[37] J. Kister, G. Assef, G. Mille, J. Metzger, Can. J. Chem. 1979, 57,
[9] W. Kangro, H. Pieper, Electrochim. Acta 1962, 7, 435.
813.
[10] M. Skyllas‐Kazacos, M. Rychik, R. G. Robins, A. G. Fane, M. A.
Green, J. Electrochem. Soc. 1986, 133, 1057.
[38] M. C. Kroon, W. Buijs, C. J. Peters, G.‐J. Witkamp, Green Chem.
2006, 8, 241.
[11] M. Rychik, M. Skyllas‐Kazacos, J. Power Sci. 1988, 22, 59.
[39] B. Gorodetsky, T. Ramnial, N. R. Branda, J. A. C. Clyburne,
Chem. Commun. 2004, 1, 1972.
[12] B. Hu, C. Debruler, Z. Rhodes, T. Liu, J. Am. Chem. Soc. 2017,
139, 1207.
[40] I. McKenzie, J.‐C. Brodovitch, P. W. Percival, T. Ramnial, J. A.
C. Clyburne, J. Am. Chem. Soc. 2003, 125, 11565.
[13] T. Liu, X. Wei, Z. Nie, V. Sprenkle, W. Wang, Adv. Energy
Mater. 2016, 6, https://doi.org/10.1002/aenm.201501449.
[41] L. P. Hammett, Chem. Rev. 1935, 17, 125.
[14] Y. Xu, Y. Wen, J. Cheng, Y. Yanga, Z. Xie, G. Cao, IEEE 2009,
978, 4244.
[42] C. Hansch, A. Leo, R. W. Taft, Chem. Rev. 1991, 91, 165.
[43] X. Zhang, L.‐X. Ma, X.‐D. Li, Synth. Met. 2014, 198, 357.
[15] B. Huskinson, M. P. Marshak, C. Suh, S. Er, M. R. Gerhardt, C.
J. Galvin, X. Chen, A. Aspuru‐Guzik, R. G. Gordon, M. J. Aziz,
Nature 2014, 505, 195.
[44] J. P. Peterson, M. R. Geraskina, R. Zhang, A. H. Winter, J. Org.
Chem. 2017, 82, 6497.
[45] O. Brugner, T. Reichenbach, M. Sommer, M. Walter, J. Phys.
Chem. A 2017, 121, 2683.
[16] C. S. Sevov, S. K. Samaroo, M. S. Sanford, Adv. Energy Mater.
2017, 7, https://doi.org/10.1002/aenm.201602027.
[46] L. P. Hammett, J. Am. Chem. Soc. 1937, 59, 96.
[17] A. J. Arduengo III, R. Krafczyk, Org. Chemie 1998, 1, 6.
[47] I. Fumiyasu, S. Hatano, J. Abe, J. Phys. Org. Chem. 2007, 20, 857.
[18] A. J. Arduengo III, R. L. Harlow, M. Kline, J. Am. Chem. Soc.
1991, 113, 361.
[48] T. Yamaguchi, M. F. Hilbers, P. P. Reinders, Y. Kobayashi, A.
M. Brouwer, J. Abe, Chem. Commun. 2015, 51, 1375.
[19] A. J. Arduengo III, H. V. R. Dias, R. L. Harlow, M. Kline, J. Am.
Chem. Soc. 1992, 114, 5530.
[49] M. J. Frisch, G. W. Trucks, H. B. Schlegel, G. E. Scuseria, M. A.
Robb, J. R. Cheeseman, G. Scalmani, V. Barone, G. A.
Petersson, H. Nakatsuji, et al. (Eds), Gaussian 09, Revision C.
01, Gaussian, Inc., Wallingford CT 2009.
[20] B. S. Tanaseichuk, Chem. Heterocycl. Compd. 1974, 8, 1173.
[21] T. Hayashi, K. Maeda, Bull. Chem. Soc. Jpn. 1960, 33, 565.
[50] C. Lee, W. Yang, R. G. Parr, Phys. Rev. B 1988, 37, 785.
[51] A. D. Becke, J. Chem. Phys. 1993, 98, 5648.
[22] J. K. Mahoney, D. Martin, F. Thomas, C. E. Moore, A. L.
Rheingold, G. Bertrand, J. Am. Chem. Soc. 2015, 137, 7519.
[52] B. Mennucci, E. Cances, J. Tomasi, J. Phys. Chem. B 1997, 101, 10506.
[53] D. White, J. Sonnenberg, J. Am. Chem. Soc. 1966, 16, 3825.
[23] J. K. Mahoney, D. Martin, F. Thomas, C. E. Moore, A. L.
Rheingold, G. Bertrand, J. Am. Chem. Soc. 2013, 135, 18766.

HOGAN AND SUTHERLAND
15 of 15
[54] S. Kazemiabnavi, Z. Zhang, K. Thornton, S. Banerjee, J. Phys.
Chem. B 2016, 120, 5691.
SUPPORTING INFORMATION
Additional Supporting Information may be found online
in the supporting information tab for this article.
[55] T. Tugsuz, Int. J. Quantum Chem. 2013, 113, 715.
[56] N. Shao, X. G. Sun, S. Dai, D. E. Jiang, J. Phys. Chem. B 2011,
115, 12120.
[57] V. D. Parker, J. Am. Chem. Soc. 1976, 98, 98.
How to cite this article: Hogan DT, Sutherland
TC. Synthesis and electrochemical evaluation of 2‐
substituted imidazolium salts. J Phys Org Chem.
2017;e3784. https://doi.org/10.1002/poc.3784
[58] J. Pommerehne, H. Vestweber, W. Guss, R. F. Mahrt, H.
Bassler, M. Porsch, J. Daub, Adv. Mater. 1995, 7.
[59] G. R. Fulmer, A. J. Miller, N. H. Sherden, A. Nudelman, B. M.
Stoltz, J. E. Bercaw, K. I. Goldberg, Organometallics 2010, 29, 2176.
[60] G. Chauvière, B. Bouteille, B. Enanga, C. De Albuquerque, S. L.
Croft, M. Dumas, J. Périé, J. Med. Chem. 2003, 46, 427.