5
94 SATYENDRA N. SHUKLA et al.
Experimental
2
-Aminopyridine (Himedia), formaldehyde (E. Merck), sodium nitrite (Himedia), cuprous
chloride (E. Merck) was used as received. Hydrochloric acid, ethanol and routine solvent
were used without further purification for synthesis purpose. FT-IR spectra were recorded in
1
KBr pellets on shimadzu-8400 PC, FT-IR spectrophotometer. H-NMR spectra were
recorded in D O on a Bruker DRX-300 NMR spectrometer. Elemental analyses (CHN) were
2
performed on Elementra Vario EL III, Elemental analyzer. Electronic absorption spectra
were recorded with shimadzu-1700, UV spectrophotometer equipped with a PC.
Conductivity measurements were carried out at 25 ºC on an EI-181 conductivity bridge with
a dipping type cell. FAB-Mass spectra were recorded on Jeol SX-102 Mass spectrometer
using NBA as matrix. The whole experimental procedure was completed in three steps.
In first step, 5,5'-methylenebis(2-aminopyridine) was prepared according to method
3
of Pradeep et al.
To solution of 2-aminopyridine, (0.9412 g, 0.01 mol) in water (25 mL), formaldehyde, (0.14 mL,
0.005 mol) was added slowly with constant stirring for 2 h. A white cream solid was precipitated,
which was filtered, washed with water, dried in vacuum and recrystallized from ethanol. (0.8642
g, 86.3%). Mp=92 °C; Found: C, 65.93; H, 6.08; N, 27.92; C H N (Mτ=200). Requires: C,
1
1
12
4
-1
6
5.99; H, 6.04; N, 27.98. νmax (KBr) cm : 3487(s), 3077(s), 2860(s), 2841(s), 1609(s), 1595(s),
1
516(s), 1430(s), 737(s). δ : 7.49-6.52(m,6H); 5.44 (brs,4H); 2.82(s,2H).
H
In second step, recrystallized 5,5'-methylenebis(2-aminopyridine), (0.130 g, 0.650 mmol),
was dissolved in concentrated hydrochloric acid (0.05 mL, 1.3 mmol) and water (3 mL). After
cooling to ~5 °C temperature, solution of sodium nitrite, (0.0897 g, 1.3 mmol) in water (5 mL)
was added drop wise. External cooling has been done to maintain the temperature.
In third step, cuprous chloride (0.1286 g, 1.3 mmol), was dissolved in concentrated
hydrochloric acid and water (1:1), in a round bottom flask and heated on water bath.
Removed water bath and support the flask on stand, now tetrazonium solution obtained in
step-2 was added drop wise with shaking. Color of reaction solution becomes light green.
The light green solution was evaporated under vacuum, washed with diethyl ether. In the
solid-state Color of the product becomes brown. (0.6284 g, 83.3 %). M =153 °C; Found: C,
D
2
2.73; H, 2.80; N, 4.82; C H N O Cl Cu (Mτ=580). Requires: C, 22.78; H, 2.78; N, 4.83.
11 16 2 4 6 2
-
1
νmax (KBr) cm : 3169(s), 3000(s) 2873(s), 2847(s), 1640(s), 1622(s), 1540(m), 1462(s),
,
-
1
-1
1
2
4
104(s), 851(s), 765(s), 518(m), 443(w), 312(w). λ
30(980). µeff=1.81 BM, Δm at 25°C (Ω in M cm ): 123. δ : 7.76-6.63(m,6H);
nm (ε in M cm ): 297(1082),
max,
-1
-
1
-1
H
+
.82(s,8H); 2.85(s,2H). m/z (FAB) 581 (M+H) .
Results and Discussion
Empirical formula of the resultant product was in conformity with elemental analysis.
+
Molecular weight was also confirmed with FAB-Mass spectrometric study, where (M+H)
peak was observed (Figure 1). The high molecular conductance was recorded in water,
4
indicated ionic nature of product .
-
1
In FT-IR spectra, three new bands appeared in region 518-312 cm , are due to Cu-O,
Cu-N and Cu-Cl bands, respectively . Two sharp peaks observed at 851 and 765 cm are
due to rocking mode of coordinated water molecule . A new sharp band appeared at 1104 cm ,
assigned for ν(C-Cl) stretching vibration. Two bands observed at 2873 and 2847 cm ,
5
,6
-1
7
-1
-
1
8
-1
assigned for -CH stretching mode . Four sharp signals observed in between 1609-1430 cm ,
2
-
1
assigned for cyclic C=C and C=N in ligand. Product displays positive shifts by ~30 cm and
also found less intense than ligand spectra, indicating that both metal centers are in