SUpRAMOleCUlAR CHeMISTRy
7
electron densities. These calculations amount to 28 elec-
trons per molecule void and may be attributed to three
water molecules.
4.953 (s, 6H,–CH2), 4.057 (t, 6H, –OCH2, J = 5.5 Hz), 3.457
(s, 3 N–H) and 3.024 (t, 6H, –NCH2CH2, J = 5.6 Hz). 13C-NMR
(150 MHz, DMSO-d6): 156.9, 149.9, 143.6, 139.6, 135.2,
130.9, 129.0, 128.0, 122.3, 115.1, 113.2, 67.2, 53.81, 46.21. IR
spectra (KBr pellet): broad band at 34280 vs (O–H and N–H),
3229 cm−1 vs(C–H), 2958 cm−1 (C–H), 1516 cm−1 vs(C=C).
eSI mass: m/z 765.15 (2L + H).
5.2. Synthesis and characterisation
5.2.1. Preparation of tripodal receptor 1L
Tris(2-aminoethyl)amine (0.300 g, 2 mM) was added to
40 ml of methanol in round bottom flask. A previously
dissolved methanolic solution of p-chlorobenzaldehyde
(0.840 g, 6 mM) was added by portions slowly in starring
condition. Finally, the whole mixture is allowed to stir for
8 h for the completion of the reaction. Then, the solvent
was removed under vacuum pressure and kept under des-
iccator for overnight. The oily product further dissolved in
methanol and one-fourth times NaBH4 added by portions
with five minutes interval and left for 24 h for the comple-
tion of the reaction. The final product was obtained after
water–chloroform work up which leaves light brown oily
product of 1L.
5.2.3. Preparation of anion complexes
Complex 1, [1LH3·F3]: The fluoride complex was prepared
from drop wise addition of HF (1.2 equivalent) to a plas-
tic vial containing methanolic solution of 1L (0.05 mM,
0.026 g) and whole mixture was stirred for one hour.
The clear solution was kept for crystallisation, and after
2–3 weeks, colourless block-shaped X-ray mountable crys-
tals were grown.
Complex 1:yield = 60%. M.p: 215 °C 1H-NMR (600 MHz,
DMSO-d6) δ (ppm): 7.584 (d, 6H, ArH, J = 7.3 Hz), 7.312
(d, 6H, ArH, J = 7.0 Hz), 4.054 (s, 6H, 3CH2), 2.816 (t, 6H, –
NCH2, J = 5.5 Hz) and 2.614 (t, 6H, –NCH2CH2, J = 5.6 Hz).
Complex 2, [L8H4∙4HSO4∙2H2O]: The sulfate complex
was obtained from drop wise addition of H2SO4 (1.2 equiv-
alent) to a test tube containing methanolic solution of 2L
(0.05 mM, 0.026 g) and whole mixture was stirred for one
hour. The clear solution was kept for crystallisation and
after 2–3 weeks colourless block-shaped X-ray mountable
crystals were grown.
1L. yield = 75%. 1H-NMR (600 MHz, DMSO-d6) δ (ppm):
7.284 (d, 6H, ArH, J = 7.3 Hz), 7.113 (d, 6H, ArH, J = 7.0 Hz),
3.813 (s, 6H,–CH2), 3.427 (s, 3 N–H), 2.816 (t, 6H, –NCH2,
J = 5.5 Hz) and 2.614 (t, 6H, –NCH2CH2, J = 5.6 Hz). 13C-NMR
(150 MHz, DMSO-d6): 139.87, 131.07, 129.21, 127.8, 62.13,
53.6, 52.12. IR spectra (KBr pellet): broad band at 3440 cm−1
vs (N–H), 3217 cm−1 vs(C–H), 2963 cm−1 (C–H), 1518 cm−1
vs(C=C). eSI mass: m/z 521.1330 (1L+H).
1
Complex 2: yield = 65%, M. p: 288–290 °C. H-NMR
(600 MHz, DMSO-d6) δ (ppm): 8.180 (d, 6H, ArH, J = 7.1 Hz,),
8.012 (d, 6H, ArH, J = 7.0 Hz,), 7.705 (d, 6H, ArH, J = 6.5 Hz),
7.016 (d, 6H, ArH, J = 7.3 Hz,), 5.512 (s, 6H, –CH2), 4.501 (t,
–OCH2, J = 5.3 6H) and 3.819 (t, 6H, –NCH2, J = 5.5) 3.516 (s,
3 N–H). IR spectra (KBr pellet): broad band at 3435 vs(O–H
and N–H), 2983 cm−1 vs(C–H), 2910 cm−1 (C–H), 2230
vs(C≡N), 1657 vs(CO), 1528 cm−1 vs(C=C).
5.2.2. Preparation of tripodal receptor 2L
preparation of second-generation tripodal receptor 2L was
1
similar to that of L except that the triamine (1L-NH2) is
used in place of tris(2-aminoethyl)amine. The nitro tripodal
(1L-NO2) was obtained from the treatment of tris(2-chloro-
ethyl)amine hydrochloride (18) (A) by SN2 substitution with
4-nitrophenol in etOH (yield 65%) followed by reduction
of nitro group to yield corresponding triamine (1L-NH2)
(yield 72%). Triamine (0.844 g, 2 mM) was added to 40 ml
of methanol in round bottom flask. A previously dissolved
methanolic solution of p-chlorobenzaldehyde (0.840 g,
6 mM) was added by portions slowly in starring condi-
tion. Finally, the whole mixture is allowed to stir for 8 h
for the completion of the reaction. Then, the solvent were
removed under vacuum pressure and kept under desic-
cator for overnight. The oily product further dissolved in
methanol and one-fourth times NaBH4 added by portions
with five minutes interval and left for 24 h for the comple-
tion of the reaction. The final product was obtained after
water–chloroform work up which leaves light brown pow-
der product of 2L.
Supplemental Material
NMR spectra, IR spectra, simulated and experimental
X-ray powder diffraction patterns, figures of the structures.
For eSI and crystallographic data in CIF or other electronic
Acknowledgements
CIF, IITG and DST-FIST have been acknowledged for providing
instrument facilities. N.H. thanks IITG for fellowship.
2L: yield = 70%. 1H-NMR (600 MHz, DMSO-d6) δ (ppm):
8.184 (d, 6H, ArH, J = 7.3 Hz), 8.013 (d, 6H, ArH, J = 7.0 Hz),
7.612 (d, 6H, ArH, J = 6.8 Hz), 6.942 (d, 6H, ArH, J = 7.1 Hz),
Disclosure statement
The authors declare no competing financial interests.