13649
3326 Liu et al.
Asian J. Chem.
RESULTS AND DISCUSSION
Crude product was washed by anhydrous ethanol and was
filtered to give compound 2 as yellow crystals.
2:Yields 87 %, 1H NMR (CDCl3, 500 MHz) δ: 8.92 (dd,
J = 7.5 Hz, 1H, ArH), 8.71 (t, J = 7.5 Hz, 1H, ArH), 8.57 (dd,
J = 7.5 Hz, 2H,ArH), 8.14 (dd, J = 7.5 Hz, 1H, ArH), 7.92 (m,
2H, ArH), 7.52 (dd, J = 2.5 Hz, 2H, ArH).
Illustrated by the case of compound 3b, the fluorescence
spectra of the compound 3b in the presence of various
concentrations of metal ion was shown in Fig. 1. As shown in
Fig. 1(A), it showed no recognition to Na+, K+, Mg2+, Ni2+,
Cu2+. And Pb2+, Zn2+, Fe2+, Ag+ had a little effect on the fluore-
scence of compound 3b. The adding of Co2+ caused fluore-
scence of compound 3b reduced without regularity, while
adding of Fe3+, Cd2+ caused fluorescence linear weak, as shown
in Fig. 1(B).
Synthesis of compound 3: The mixture of compound 2
(10 mmol) and different amine or benzyl alcohol (12 mmol)
was refluxed in ethylene glycol monomethyl ether (50 mL)
with copper sulphate as catalyzer for 6 h, then the crude
produce was purified by column chromatography to give 3 as
yellow-purple crystals.
3a: Yields 70 %, m.p. 200.2-202.8 ºC, 1H NMR (CDCl3,
500 MHz) δ: 8.87(d, J = 5 Hz, 1H, ArH), 8..64 (d, J = 5 Hz,
1H, ArH), 8.00 (d, J = 5 Hz, 1H, ArH), 7.91(dd, J = 5 Hz, 1H,
ArH), 7.69 (dd, J = 7.5 Hz, 1H, ArH), 7.48 (d, J = 5 Hz, 1H,
ArH), 6.77(dd, J = 2.5 Hz, 1H, ArH), 3.42(d, J = 7.5 Hz, 2H,
CH2), 1.82 (q, J = 7.5 Hz, 2H, CH2), 1.36-1.39 (m, J = 12.5
Hz, 1H, NH), 1.29-1.32 (m, J = 10 Hz, 4H, CH2), 1.07(d, J =
7.5 Hz, 3H, CH3), MS m/z (%): 342 (M + H).
3b: Yields 80 %, m.p. 230.6-232.2 ºC, 1H NMR (CDCl3,
500 MHz) δ: 8.28 (d, J = 7.5 Hz, 1H, ArH), 8.16 (d, J = 7.5
Hz, 1H, ArH), 8.01 (d, J = 7.5 Hz, 1H, ArH), 7.64 (dd, J = 7.5
Hz, 1H, ArH), 7.59 (d, J = 7.5 Hz, 1H, ArH), 7.22 (dd, J = 7.5
Hz, 2H, ArH), 7.18 (d, J = 7.5 Hz, 1H, ArH), 4.0 (t, 1H, NH),
3.65 (s, 1H, OH), 3.58 (q, J = 7.1 Hz, 2H, CH2) 3.48 (q, J =
7.1 Hz, 2H, CH2). MS m/z (%): 330 (M + H).
3c: Yields 72 %, m.p. 260.1-261.8 ºC, 1H NMR (CDCl3,
500 MHz) δ: 8.28 (d, J = 7.5 Hz, 1H, ArH), 8.16 (d, J = 7.5
Hz, 1H, ArH), 8.01 (d, J = 7.5 Hz, 1H, ArH), 7.64 (dd, J = 7.5
Hz, 1H, ArH), 7.59 (d, J = 7.5 Hz, 1H, ArH), 7.28 (d, J = 7.55
Hz, 1H, ArH), 7.22 (dd, J = 7.5 Hz, 2H, ArH), 7.20 (dd, J =
7.5 Hz, 2H, ArH), 7.18 (d, J = 7.5 Hz, 1H, ArH), 6.81 (dd, J =
7.5 Hz, 1H, ArH), 4.0 (s, 1H, NH). MS m/z(%): 374(M-H).
3d: Yields 60 %, m.p. 270.3-272.1 ºC, 1H NMR (CDCl3,
500 MHz) δ: 8.28 (d, J = 7.5 Hz, 1H, ArH), 8.23 (d, J = 7.5
Hz, 1H, ArH), 8.16 (d, J = 7.5 Hz, 1H, ArH), 8.01 (d, J = 7.5
Hz, 1H, ArH), 7.64 (d, J = 7.5 Hz, 1H, ArH), 7.58 (d, J = 7.5
Hz, 1H, ArH), 7.49 (d, J = 7.5 Hz, 1H, ArH), 7.42 (d, J = 7.5
Hz, 1H, ArH), 7.21 (d, J = 7.5 Hz, 1H, ArH), 7.20 (dd, J = 7.5
Hz, 2H, ArH), 7.18 (dd, J = 7.5 Hz, 1H, ArH), 6.51 (d, J = 7.5
Hz, 1H, ArH), 6.48 (d, J = 7.5 Hz, 1H, ArH), 3.52 (s, 2H,
CH2), 3.19 (s, 2H, CH2). MS m/z (%): 377 (M + H).
400
(A)
300
200
100
0
450
500
550
600
650
Wavelength (nm)
Wav el engt h
1
9
a
400 (B)
300
200
100
0
450
500
550
600
6500
Wavelength (nm)
Wavel engt h
Fig. 1. Fluorescence spectra of the compound 3b in the presence of various
concentrations of sodium (A) and ferric (B) ions. The concentrations
of Fe3+: 1 → 9 were 0, 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0 × 10-4 mol
L-1, respectively
Fluorescence quenching of compound 3 by metal ions
was confirmed by the Stern-Volmer eqn.12,13 1 and modified
Stern-Volmer eqn.12,13 2 as shown in Fig. 2 and the values of
Stern-Volmer quenching constant (KCV) and binding constants
(Ka) were showed in the Tables 1 and 2, respectively.
Recognition ability to metal ions detected by fluore-
scence spectroscopy: The metallic ion recognition properties
of the compounds 3 were investigated by fluorescence quenching
spectroscopy. At room temperature, compounds 3 and metal
ions nitrate (NaNO3, KNO3, Mg(NO3)2, Fe(NO3)2, Fe(NO3)3,
Cd(NO3)2, Pb(NO3)2, Co(NO3)2, Cu(NO3)2, AgNO3, Ni(NO3)2
and Zn(NO3)2) were dissolved in DMF-water (7:3, v:v) to
proper concentration, respectively. The fluorescence spectro-
scopy was scanned in the RF-5301 fluorospectrophoto meter
after mixed solution reached a steady state.
F0
= 1+ Kq τ0c(Q) = 1+ Kcv c(Q)
(1)
F
F0
F0
1
1
=
F0 − F ∆F faKa c(Q) fa
=
+
(2)
As shown in Tables 1 and 2, all the compounds showed
recognition to ferric ion and the quenching constant (KCV) and
binding constants (Ka) values were in the range of 102-103 M-1.
The order was: 3c > 3b > 3a > 3d. It was possibly due to that
ferric ion had strong oxidative which made the fluorescence
quenching phenomenon stronger. In addition, the electron
Recognition ability to metal ions confirmed by UV-
visible spectrum: At room temperature, compounds 3 and
metal ions nitrate [KNO3 and Fe(NO3)3] were dissolved in
DMF-water (7:3, v:v) to proper concentration, respectively.
The UV-visible spectrum was scanned in the TU-1901 spectro-
photometer after mixed solution reached a steady state.
2