Progress toward colorimetric and fluorescent detection of carbonyl sulfide

Article abstract of DOI:10.1039/d0cc04528d

We report here that a fluorescent benzobisimidazolium salt (TBBI) can be used for the fluorescent and colorimetric detection of carbonyl sulfide (COS) over related heterocumulenes including CO2 and CS2 in wet MeCN. The reaction between TBBI and COS in the presence of fluoride yields a highly fluorescent (λem = 354 nm) and colored product (λmax = 321, 621 nm), that is readily observed by the naked eye. We view these results as a first step toward developing activity-based probes for COS detection.

Full text of DOI:10.1039/d0cc04528d

View Article Online
View Journal
ChemComm
Chemical Communications
Accepted Manuscript
This article can be cited before page numbers have been issued, to do this please use: M. Cerda, J. M.
Fehr, T. Sherbow and M. D. Pluth, Chem. Commun., 2020, DOI: 10.1039/D0CC04528D.
Volume 54
Number
January 2018
Pages 1-112
This is an Accepted Manuscript, which has been through the
Royal Society of Chemistry peer review process and has been
accepted for publication.
1
4
ChemComm
Chemical Communications
rsc.li/chemcomm
Accepted Manuscripts are published online shortly after acceptance,
before technical editing, formatting and proof reading. Using this free
service, authors can make their results available to the community, in
citable form, before we publish the edited article. We will replace this
Accepted Manuscript with the edited and formatted Advance Article as
soon as it is available.
You can find more information about Accepted Manuscripts in the
Information for Authors.
Please note that technical editing may introduce minor changes to the
text and/or graphics, which may alter content. The journal’s standard
Terms & Conditions and the Ethical guidelines still apply. In no event
shall the Royal Society of Chemistry be held responsible for any errors
or omissions in this Accepted Manuscript or any consequences arising
from the use of any information it contains.
ISSN 1359-7345
COMMUNICATION
S. J. Connon, M. O. Senge et al.
Conformational control of nonplanar free base porphyrins:
towards bifunctional catalysts of tunable basicity
rsc.li/chemcomm

Page 1 of 6
Please d oC hn eo mt Ca do mj u ms t margins
View Article Online
DOI: 10.1039/D0CC04528D
COMMUNICATION
Progress Toward Colorimetric and Fluorescent Detection of
Carbonyl Sulfide
†
†
†
Matthew M. Cerda, Julia M. Fehr, Tobias J. Sherbow, and Michael D. Pluth*
Received 00th January 2020,
Accepted 00th January 2020
DOI: 10.1039/x0xx00000x
We report here that a fluorescent benzobisimidazolium salt (TBBI) properties akin to H
2
S.14 As the potential roles of COS in
biological systems and investigations into COS releasing
compounds expand, a currently unmet need to further such
investigations is the development of minimally invasive and
sensitive methods for COS detection. Based on the significant
impacts of colorimetric and fluorescent activity-based probes
for the detection of reactive sulfur species, such as cysteine,
can be used for the fluorescent and colorimetric detection of
carbonyl sulfide (COS) over related heterocumulenes including CO
and CS in wet MeCN. The reaction between TBBI and COS in the
2
2
presence of fluoride yields a highly fluorescent (em = 354 nm) and
colored product (max = 321, 621 nm), that is readily observed by
the naked eye. We view these results as a first step toward
developing activity-based probes for COS detection.
reduced glutathione, and H
2
S, we envisioned that analogous
15, 16
platforms could be developed for COS detection.
To the
best of our knowledge, no activity-based probes for COS
detection or differentiation from the related heterocumulenes
CO or CS have been reported.
2 2
Carbonyl sulfide (COS) is an important organosulfur species
in the global sulfur cycle that is generated during the burning
1
of biomass,2
,
3
combustion of biofuels, and in different
4
5
production processes in the pulp and paper industries. In
addition, geochemical production of COS arises from volcanic
activity, emission from hot springs, and deep sea thermal
vents. Although the chemical properties and reactivity of COS
have long been established, the biological implications of COS
6
7
8
have only recently begun to emerge. As an example, treatment
of -amino acids with COS under prebiotic reaction conditions
results in the formation of dipeptides, demonstrating the
9
potential role of COS in origin of life chemical ligation. Aligned
1
0
with our interests in studying biological reactive sulfur species,
our group has recently advanced the use of COS-releasing
compounds for the controlled release of hydrogen sulfide (H S)
due to the rapid catalyzed hydrolysis of COS by carbonic
2
Figure 1. (a) Reaction of CO
2
and TBBI in the presence of fluoride. (b)
1
1
anhydrase, a ubiquitous metalloenzyme. Although enzymatic
pathways for endogenous COS production in mammals remain
undiscovered, COS has been detected in porcine cardiovascular
tissues12 and exhaled breath from cystic fibrosis patients by
using gas chromatography mass spectrometry. More recently,
Reaction between CS and TBBI in the presence of fluoride. (c) Proposed
2
reaction between COS and TBBI in the presence of fluoride.
13
Based on the electrophilicity and structural similarities
between carbon dioxide (CO ), carbon disulfide (CS ), and COS,
2 2
we anticipated that a nucleophilic platform could be used to
develop chemical tools for COS detection. For example, N-
7
2
in our investigation of esterase-sensitive COS-based H S donors
in human lung epithelial (BEAS2B) cells, we observed COS-
dependent inhibition of mitochondrial bioenergetics. This
finding suggests that COS may possess biological activities and heterocyclic carbenes can insert into heterocumulenes, which
1
7
18
19
has been demonstrated separately for CO
2 2
, CS , and COS,
respectively. Bridging the gap to heterocumulene detection, the
2
0
vast majority of work has aimed at the spectroscopic or
electrochemical detection of CO
a. Department of Chemistry and Biochemistry, Materials Science Institute, Knight
Campus for Accelerating Scientific Impact, Institute of Molecular Biology,
University of Oregon, Eugene, Oregon, 97403, USA. pluth@uoregon.edu
2
1
2
. Of these reported methods,
we were drawn to the prior use of a fluorescent, colorimetric
2
detection. In this
system, treatment of TBBI with tetra-n-butylammonium
†
These authors contributed equally
2
2
benzobisimidazolium probe (TBBI) for CO
Electronic Supplementary Information (ESI) available: Experimental procedures and
COS synthesis details. See DOI: 10.1039/x0xx00000x
Please do not adjust margins

Please d oC hn eo mt Ca do mj u ms t margins
Page 2 of 6
COMMUNICATION
Chem Commun
fluoride (TBAF) produces a “carbene-like” intermediate23 that and concomitant increase of a new absorbance at 321 nm. We
View Article Online
DOI: 10.1039/D0CC04528D
2 2
readily reacts with CO through carbene insertion into CO and note that this observed reaction with COS did not occur if
2
subsequent hydrolysis to form bicarbonate (Figure 1a). This anhydrous MeCN was used, which highlights that residual H O
1
3
reactivity was also investigated for CS
and shown to result in the generation of an imidazolium- is not observed upon reaction of TBBI with CO
dithiocarboxylate betaine through carbene insertion into CS presence of TBAF.
Figure 1b). Building from structural similarities between these
2
by C NMR spectroscopy is required. The new absorbance at 321 nm is unique to COS and
2
or CS in the
2
2
(
compounds, we hypothesized the treatment of TBBI with COS
in the presence of fluoride would provide a unique
spectroscopic response for COS that would be distinguishable
from that of CO and CS . Based on this motivation, we report
2 2
here the first demonstration of selective COS detection by UV-
Vis and fluorescence spectroscopy.
One challenge when working with COS is that commercial
2
sources often contain H S as a common impurity. To overcome
this challenge, we prepared COS through the acidic hydrolysis
2
4
of KSCN using modifications of known methods (Figure 2a).
Based on the growing interest in various aspects of COS
chemistry, including delivery, organometallic chemistry, and
chemical biology, we have included this method here and in the
Supporting Information. A key requirement when preparing
COS is purification of the product, which can be accomplished
by sparging through aqueous KOH, aniline in anhydrous
ethanol, ice water, and neat H SO . The purified COS can be
2 4
collected and stored in a gas storage flask or added directly into
a solution or NMR tube for use as a reactant or reagent (Figure
1
3
2
b). COS has a characteristic C chemical shift at  = 154.3 ppm
-1
(CD
3
CN) and IR stretch at 2927 and 2909 cm , which match
2
5
prior reports.
Figure 3. (a) Reaction of TBBI with COS. (b) UV-Vis spectra and (c)
fluorescence spectra for TBBI (15 M), TBAF (90 M), and COS (5.0 mL).
Building from this observation, we next investigated the
Figure 2. (a) Acid-mediated hydrolysis of KSCN to generate COS. (b)
Schematic of laboratory-scale COS synthesis and purification.
reaction by fluorescence spectroscopy. The parent TBBI
compound (15 M, MeCN containing 1% (v/v) H
2
O) showed
To investigate the proposed strategy of carbene insertion negligible fluorescence when excited at 321 nm, but addition of
2
2
for COS detection, we prepared TBBI and monitored its TBAF (6.0 equiv.) resulted in the appearance of a broad
reactivity toward COS in the presence of TBAF by UV-Vis emission centered at 434 nm, which we attribute to formation
spectroscopy (Figure 3a). The parent TBBI compound (15 M in of the hydrogen bonded TBBI intermediate. Subsequent
MeCN containing 1% (v/v) H
2
O) has an absorption band addition of COS in 0.5 mL increments led to a clean ratiometric
centered at 290 nm, which shifts to 344 nm upon addition of response, with a decrease at the 434 nm emission and
TBAF (6.0 equiv.). This change in absorbance is consistent with concomitant increase at 354 nm (Figure 3c). The product
the previous report of hydrogen bond formation between the formed upon COS addition is persistent, unlike in the case for
–
22
C1-H in TBBI and F . Subsequent addition of COS in 0.5 mL CO
2
in which rapid hydrolysis to bicarbonate is observed. A plot
increments resulted in a decrease in the 344 nm absorbance of COS concentrations against the ratio of fluorescence
2
| Chem. Commun., 2020, 00, 1-3
This journal is © The Royal Society of Chemistry 2020
Please do not adjust margins

Page 3 of 6
Please d oC hn eo mt Ca do mj u ms t margins
Chem Commun
intensities at 354 and 434 nm is linear (R = 0.986), which
COMMUNICATION
2
The stability and unique spectroscopic propertiVeieswoAfrtpicrleoOdnulincet
suggests that this detection method could be used to quantify formed upon COS addition prompted usDtoOIi:n1v0e.1s0t3ig9/aDt0eCwCh04e5t2h8eDr
COS concentrations (see Supporting Information, Figure S3). this TBBI system could be used for naked-eye optical detection
Taken together, these results demonstrate that TBBI can be of COS. The recognition of CS by 10 mM TBBI in the presence
2
used to spectroscopically distinguish between CO
in the presence of the fluoride.
2
, CS
2
, and COS of fluoride was previously reported to generate a color change
from clear to yellow red and form an imidazolium-
To confirm the formation of the proposed thiocarboxylate dithiocarboxylate betaine.22 To further investigate this
product, we accessed this compound by treatment of TBBI with reactivity, we charged a series of cuvettes with 10 mM TBBI and
KHMDS (2.2 equiv.) and subsequent addition of COS (g). The 60 mM TBAF in MeCN containing 1% (v/v) H
addition of COS (g) to a solution of doubly deprotonated TBBI in hydrogen bonded intermediate; this was followed by addition
THF-d yielded a yellow-orange solution and the appearance of of CO , CS , or COS (Figure 5). Consistent with previous results,
a new resonance in the C NMR spectrum at 190.34 ppm the cuvette containing CO yielded a white precipitate
corresponding to thiocarboxylate formation (Figure 4a and b). corresponding to the bicarbonate salt of TBBI, whereas the
This observed chemical shift is within the range of previously cuvette containing CS yielded a pale orange solution. The
We further reaction between TBBI and COS yielded a teal green color and
characterized this compound by IR spectroscopy and observed transitioned to a dark forest green upon standing for an
2
O to generate the
8
2
2
1
3
2
2
1
9
synthesized imidazolium-2-thiocarboxylates.
-1
C-S and C=O stretching frequencies at 990 and 1524 cm , extended period of time. This color is due to the combination of
respectively (see Supporting Information, Figure S6). We next the major broad absorbance at 321 nm, which tails into the
measured the fluorescence spectrum of this product in MeCN visible region of the spectrum, and a significantly weaker
(ex = 321 nm, em = 330-600 nm) and observed a nearly absorbance at 621 nm that appears upon COS addition (See
identical match to the spectroscopic properties observed under Supporting Information, Figure S7). These results demonstrate
experimental conditions (Figure 4c). When taken together, the the unique ability of TBBI to serve as a versatile platform for
combined 13C NMR data and fluorescence spectroscopy data distinct recognition of CO
both support the formation of the proposed thiocarboxylate detection.
upon treatment of TBBI with F and COS (g).
2 2
, COS, and CS by naked eye
–
2 2
Figure 5. Naked-eye detection and differentiation of CO , CS , and COS using
TBBI (10 mM) in the presence of TBAF (60 mM).
In summary, we have demonstrated that the TBBI platform
can be used for the colorimetric and fluorescent detection of
COS. Importantly, these spectroscopic responses for COS are
2 2
distinct from those generated by CO or CS . We view that these
advances provide a first step toward developing activity-based
chemical tools for COS detection and imaging, which we
anticipate can be used to investigate the growing evidence for
a biological role of COS in complex environments.
Figure 4. (a) The 13C{ H} NMR spectrum of TBBI (30 mM) treated with KHMDS
(
1
8
13
1
2.2 equiv.) in THF-d . (b) The C{ H} NMR spectrum following the addition
of COS (g) to a solution of doubly deprotonated TBBI. (c) Normalized
fluorescence spectra comparing emission from TBBI + TBAF + COS and the
2
synthesized thiocarboxylate adduct (TBBI·(COS) ).
This journal is © The Royal Society of Chemistry 2020
Chem. Commun., 2020, 00, 1-3 | 3
Please do not adjust margins

Please d oC hn eo mt Ca do mj u ms t margins
Page 4 of 6
COMMUNICATION
Chem Commun
Conflicts of interest
View Article Online
DOI: 10.1039/D0CC04528D
There are no conflicts to declare.
Acknowledgements
This research was supported by the NIH (R01GM113030). NMR
instrumentation in the UO CAMCOR facility is supported by the
NSF (CHE-1427987 and CHE-1625529).
References
1
2
1
3
4
. C.-L. Lee and P. Brimblecombe, Earth Sci Rev, 2016, 160, 1-18.
. M. O. Andreae and P. Merlet, Global Biogeochem Cycles, 2001,
5, 955-966.
. M. O. Andreae, Atmos Chem Phys, 2019, 19, 8523-8546.
. J. E. Campbell, M. E. Whelan, U. Seibt, S. J. Smith, J. A. Berry and
T. W. Hilton, Geophys Res Lett, 2015, 42, 3004-3010.
. E. Vainio, A. Brink, N. Demartini, M. Hupa, H. Vesala, K.
Tormonen and T. Kajolinna, J. Pulp Pap. Sci., 2010, 36, 135-142.
5
6
7
8
2
9
2
1
1
5
1
. S. F. Watts, Atmos Environ, 2000, 34, 761-779.
. R. J. Ferm, Chem Rev, 1957, 57, 621-640.
. A. K. Steiger, Y. Zhao and M. D. Pluth, Antioxid Redox Signal,
018, 28, 1516-1532.
. L. Leman, L. Orgel and M. R. Ghadiri, Science, 2004, 306, 283-
86.
0. N. Lau and M. D. Pluth, Curr Opin Chem Biol, 2019, 49, 1-8.
1. C. M. Levinn, M. M. Cerda and M. D. Pluth, Acc Chem Res, 2019,
2, 2723-2731.
2. M. Balazy, I. A. Abu-Yousef, D. N. Harpp and J. Park, Biochem
Biophys Res Commun, 2003, 311, 728-734.
3. M. A. Kamboures, D. R. Blake, D. M. Cooper, R. L. Newcomb, M.
1
Barker, J. K. Larson, S. Meinardi, E. Nussbaum and F. S. Rowland,
Proc Natl Acad Sci U S A, 2005, 102, 15762-15767.
1
4. A. K. Steiger, M. Marcatti, C. Szabo, B. Szczesny and M. D. Pluth,
ACS Chem Biol, 2017, 12, 2117-2123.
1
1
2
1
5. J. Zhou and H. Ma, Chem Sci, 2016, 7, 6309-6315.
6. X. Jiao, Y. Li, J. Niu, X. Xie, X. Wang and B. Tang, Anal Chem,
018, 90, 533-555.
7. A. Tudose, A. Demonceau and L. Delaude, Journal of
Organometallic Chemistry, 2006, 691, 5356-5365.
1
2
1
8. L. Delaude, A. Demonceau and J. Wouters, Eur J Inorg Chem,
009, 2009, 1882-1891.
9. M. Hans, J. Wouters, A. Demonceau and L. Delaude, Eur J Org
Chem, 2011, 2011, 7083-7091.
2
8
2
2
2
0. X. Zhou, S. Lee, Z. Xu and J. Yoon, Chem Rev, 2015, 115, 7944-
000.
1. S. Neethirajan, D. S. Jayas and S. Sadistap, Food Bioprocess Tech,
008, 2, 115-121.
2. Z. Guo, N. R. Song, J. H. Moon, M. Kim, E. J. Jun, J. Choi, J. Y. Lee,
C. W. Bielawski, J. L. Sessler and J. Yoon, J Am Chem Soc, 2012, 134,
1
2
2
2
4
2
2
7846-17849.
3. M. N. Hopkinson, C. Richter, M. Schedler and F. Glorius, Nature,
014, 510, 485-496.
4. P. D. N. Svoronos and T. J. Bruno, Indust Eng Chem Res, 2002,
1, 5321-5336.
5. C.-J. Zhang and X.-H. Zhang, Macromolecules, 2019, 53, 233-
39.
4
| Chem. Commun., 2020, 00, 1-3
This journal is © The Royal Society of Chemistry 2020
Please do not adjust margins

Page 5 of 6
Please d oC hn eo mt Ca do mj u ms t margins
Chem Commun
COMMUNICATION
TOC Figure
View Article Online
DOI: 10.1039/D0CC04528D
This journal is © The Royal Society of Chemistry 2020
Chem. Commun., 2020, 00, 1-3 | 5
Please do not adjust margins

ChemComm
Page 6 of 6
View Article Online
DOI: 10.1039/D0CC04528D