(1.1 g, 4.78 mmol) was added and it was stirred at r.t for 24 h.
Then it was refluxed at 80 ◦C for 2 h. The product was precipitated
out from the solution. It was cooled, filtered and washed with
methanol, ether and finally air dried to obtain a solid.
calc. for C15H14ClN7O4: C, 45.99; H, 3.60; N, 25.03. Found: C,
46.05; H 3.33; N 24.70.
1
S9. Yellow solid. (yield 75%). H NMR (300 MHz, DMSO-
d6) d 8.69 (br, NH), 8.53 (s, 2H), 8.29 (d, 4H), 8.21 (d, J = 6.76 Hz,
4H); 13C NMR (75 MHz, DMSO-d6) d 154.1, 148.6, 146.8, 140.1,
129.2, 124.3; MS (positive ESI): m/z 355.8 [HL]+(100%). Anal.
calc. for C15H14ClN7O4: C, 45.99; H, 3.60; N, 25.03. Found: C,
45.86; H 3.49; N 24.99.
S1. Off white solid. (yield 64%). 1H NMR (300 MHz, DMSO-
d6) d 12.31 (br, NH), 8.53 (s, 2H), 8.45 (s, 2H), 7.95 (s, 4H), 7.49 (s,
6H); 13C NMR (75 MHz, DMSO-d6) d 158.1, 154.0, 138.5, 136.0,
134.0, 133.1; MS (positive ESI): m/z 265.9 [HL]+(100%). Anal.
calc. for C15H16ClN5: C, 59.70; H, 5.34; N, 23.21. Found: C, 59.47;
H 5.30; N 23.09.
1
S10. Greenish white solid (yield 70%). H NMR (300 MHz,
DMSO-d6) d 11.83 (s, 1H), 11.61 (br, NH), 8.58 (s, 1H), 8.37 (d,
J = 7.6 Hz, 1H), 7.98 (s, 1H), 7.89 (s, 1H), 7.49 (d, J = 7.5 Hz,
1H), 7.28–7.18 (m, 2H); 13C NMR (75 MHz, DMSO-d6) d 152.2,
146.9, 137.7, 132.7, 124.5, 123.4, 122.9, 121.3, 112.5, 111.2; MS
(positive ESI): m/z 343.8 [L] (100%). Anal. calc. for C19H18ClN7:
C, 60.08; H, 4.78; N, 25.81. Found: C, 59.91; H 4.81; N 25.80.
S2. Light yellow solid. (yield 80%). 1H NMR (300 MHz,
DMSO-d6) d 12.51 (br, NH), 9.42 (s, 1H), 8.64 (s, 1H), 8.44-8.40
(m, 2H), 8.08 (d, J = 8.1 Hz, 1H), 8.03 (d, J = 8.1 Hz, 1H), 7.71–7.58
(m, 3H); 13C NMR (75 MHz, DMSO-d6) d 153.0, 147.9, 133.8,
131.7, 131.1, 129.3, 129.0, 127.9, 126.8, 126.7, 126.0, 123.3; MS
(positive ESI): m/z 366.2 [HL]+(100%). Anal. calc. for C23H20ClN5:
C, 68.74; H, 5.02; N, 17.43. Found: C, 68.31; H 5.10; N 17.41.
Conclusions
S3. Yellow solid. (yield 81%). 1H NMR (300 MHz, DMSO-d6)
d 12.65 (br, NH), 9.66 (s, 1H), 8.77 (s, 1H), 8.56 (d, J = 8.7 Hz, 2H),
8.18 (d, J = 8.1 Hz, 2H); 13C NMR (75 MHz, DMSO-d6) d 152.8,
149.0, 130.8, 129.9, 129.7, 128.9, 127.4, 125.7, 124.9, 124.8; MS
(positive ESI): m/z 466.3 [HL]+(100%). Anal. calc. for C31H24ClN5:
C, 74.17; H, 4.82; N, 13.95. Found: C, 73.98; H 4.73; N 13.90.
In summary, we have synthesized a new series of guanidinium
chloride derivatives (S1–S10) based on increasing aromaticity,
induction effect, positional isomeric effect and NIR sensing ability
of the substituted functional group attached to the guanidinium
moiety. This series of sensor molecules shows selective colour
changes with fluoride and in most of the cases no change in
colour or absorption spectra are observed with closely related
basic anions like acetate and phosphate. The spectrum of colour
change across the series with the fluoride shows a pattern of colour
changes as well as absorption spectra which could be utilized for its
confirmed detection. Interestingly, we also demonstrate that one
of the sensor molecules can be utilized to differentiate fluoride,
acetate and dihydrogen phosphate by colourimetric and optical
studies. Further, single crystal X-ray structural analyses supports
–NH deprotonation in the presence of highly basic F- and 1 : 1
binding in the presence of less basic anion benzoate.
1
S4. Yellow solid. (yield 72%). H NMR (300 MHz, DMSO-
d6) d 12.30 (br, NH), 9.71 (brs, 1H), 9.05 (d, J = 8.2 Hz, 1H), 8.74
(s, 1H), 8.62 (d, J = 9.4 Hz, 1H), 8.44–8.39 (m, 4H), 8.34–8.26 (m,
2H), 8.17–8.12 (t, 1H); 13C NMR (75 MHz, DMSO-d6) d 152.9,
147.5, 133.0, 131.2, 130.5, 129.7, 129.5, 129.2, 127.9, 127.2, 126.8,
126.5, 126.4, 125.6, 125.1, 124.5, 124.2, 122.2; MS (positive ESI):
m/z 513.9 [HL]+(100%). Anal. calc. for C35H24ClN5: C, 76.42; H,
4.40; N, 12.73. Found: C, 76.44; H 4.29; N 12.61.
S5. Yellow white solid. (yield 80%). 1H NMR (300 MHz,
DMSO-d6) d 12.16 (br, NH), 8.38 (s, 1H), 7.88 (d, J = 8.6 Hz, 2H),
7.02 (d, J = 8.6 Hz, 2H), 3.82 (s, 3H); 13C NMR (75 MHz, DMSO-
d6) d 161.4., 152.6, 148.5, 129.6, 125.9, 114.26, 55.42; MS (positive
ESI): m/z 326.1 [HL]+(100%). Anal. calc. for C17H20ClN5O2: C,
56.43; H, 5.57; N, 19.36. Found: C, 56.07; H 5.24; N 19.25.
Acknowledgements
P.G. gratefully acknowledges the Department of Science and
Technology (DST), New Delhi for financial support. P.B. would
like to acknowledge CSIR, India for SRF. X-ray crystallography
study is performed at the DST-funded National Single Crystal
X-ray Diffraction Facility at the Department of Inorganic Chem-
istry, IACS.
S6. White solid. (yield 70%). 1H NMR (300 MHz, DMSO-d6)
d 12.7 (br, NH), 8.60 (s, 2H), 8.34 (s, 2H); 13C NMR (75 MHz,
DMSO-d6) d 153.3, 146.8, 143.4, 138.4, 136.1, 109.3; MS (positive
ESI): m/z 445.9 [L]+. Anal. calc. for C15H6ClF10N5: C, 37.40; H,
1.26; N, 14.54. Found: C, 37.21; H 1.32; N 14.39.
Notes and references
S7. Off white solid. (yield 81%). 1H NMR (300 MHz, DMSO-
d6) d 12.76 (br, NH), 8.88 (s, 1H), 8.77 (s, 1H), 8.49 (d, J = 8.1 Hz,
1H), 8.12 (d, J = 8.4 Hz, 1H), 7.86 (t, J = 9.3 Hz, 1H), 7.74 (t,
J = 9.5 Hz, 1H); 13C NMR (75 MHz, DMSO-d6) d 153.6., 148.9,
145.3, 134.2, 131.9, 129.4, 128.2, 125.3; MS (positive ESI): m/z
356.1 [HL]+(100%). Anal. calc. for C15H14ClN7O4: C, 45.99; H,
3.60; N, 25.03. Found: C, 46.06; H 3.56; N 25.35.
1 (a) K. L. Kirk, Biochemistry of the Halogens and Inorganic Halides,
Plenum Press, New York, 1991, p 58; (b) Supramolecular Chemistry
of Anions, A. Bianchi, K. Bowman-James and E. Garc´ıa-Espan˜a,
ed., Woley-VCH, New York, 1997; (c) P. D. Beer and P. A. Gale,
Angew. Chem., Int. Ed., 2001, 40, 486; (d) J. L. Sessler, P. A. Gale
and W.-S. Cho, Anion Receptor Chemistry, The Royal Society of
Chemistry, Cambridge, UK, 2006; (e) M. Cametti and K. Rissanen,
Chem. Commun., 2009, 2809; (f) P. A. Gale, S. E. Garc´ıa-Garrido and
J. Garric, Chem. Soc. Rev., 2008, 37, 151–190; (g) T. Gunnlaugsson, A.
P. Davis, J. E. O’Brien and M. Glynn, Org. Lett., 2002, 4, 2449; (h) J.
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2 Representative examples: (a) P. D. Beer and F. Szemes, J. Chem. Soc.,
Chem. Commun., 1995, 2245; (b) P. A. Gale, J. L. Sessler, V. Kra´l and
V. Lynch, J. Am. Chem. Soc., 1996, 118, 5140; (c) P. D. Beer, F. Szemes,
V. Balzani, C. M. Sala, M. G. B. Drew, S. W. Dent and M. Maestri, J.
1
S8. Yellow solid. (yield 85%). H NMR (300 MHz, DMSO-
d6) d 12.59 (br, NH), 8.83 (s, 1H), 8.81 (s, 1H), 8.75 (s, 1H); 8.39
(d, J = 4.8 Hz, 1H), 8.30 (d, J = 5.1 Hz, 1H), 7.78 (t, J = 9.6 Hz,
1H) 13C NMR (75 MHz, DMSO-d6) d 148.9, 135.7, 134.7, 130.8,
125.5, 122.5; MS (positive ESI): m/z 355.9 [HL]+(100%). Anal.
1978 | Org. Biomol. Chem., 2011, 9, 1972–1979
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