1502
E. Gondek et al. / Spectrochimica Acta Part A 75 (2010) 1501–1505
Scheme 1. Melting, 140–200 ◦C.
Table 1
Principal spectral positions of the absorption and of the corresponding photoluminescent (PL) bands.
Spectral positions of the absorption maxima (nm)
Spectral positions of the
emission maxima (nm)
The high frequency band
The middle frequency band
The long range frequency band
Mol. 1
Mol. 2
Mol. 3
Mol. 4
299
309
311
315
314, 329
322
325
395
369, 386
381
469
430
463
453
327
385
efficiency of their using together with other parameters. A physical
origin of the observed effects will be explained following the cor-
relation with the values of the chromophore ground state dipole
moments.
2.1.4. 3-Methyl-1-phenyl-6-triphenylmethyl-1H-pyrazolo
[3,4-b]quinoline (Mol. 3)
In a round-bottomed flask aniline 1 (0.01 mol, 3.35 g) and 5-
chloro-1-phenyl-3-methylpyrazolo-3-carbaldehyde 2c (0.01 mol,
2.20 g) were heated together at 140–180 ◦C for 45 min. After cooling
the melt was boiled with MeOH and the insoluble residue was fil-
tered off and dissolved in CHCl3. The solution was filtered through
a short column packed with alumina (Merck 60, 70–230 mesh).
The final purification was made on column packed with silica-gel
(Merck 60, 70–230 mesh) using toluene as eluent.
2. Experimental
2.1. Synthesis – general procedure
Light yellow crystals, 3.3 g, yield 65%, mp. 261–262 ◦C (toluene)
1H NMR(300 MHz, CDCl3, ı ppm): 8.53–8.50 (m, 2H); 8.46 (s,
1H, 4-H); 8.01 (d, J = 9.2 Hz, 1H, 8-H); 7.88 (d, J = 2.3 Hz, 1H, 5-H);
7.59–7.53 (m, 3H); 7.35–7.21 (m, 15H); 2.75 (s, 3H, Me).
Anal. Calc. for C36H27N3: C 86.20; H 5.43; N 8.38. Found C 86.01;
H 5.27; N 8.27.
2.1.1. The synthesis of aldehydes 2-general procedures
Phosphorus oxychloride (0.7 mol, 6.4 ml) was added drop wise
whereupon the reaction mixture was refluxed for 1 h. After
cooling the reaction mixture was poured on 60 ml ice/water mix-
ture. The precipitated was filtered, dried and crystallized from
alcohol [10]
2.1.5. 1,3-Dimethyl-6-triphenylmethyl-1H-pyrazolo
[3,4-b]quinoline (Mol. 4)
In a round-bottomed flask aniline 1 (0.01 mol, 3.35 g) and 5-
chloro-1,3-dimethylpyrazolo-3-carbaldehyde 2d (0.01 mol, 1.58 g)
were heated together at 140–180 ◦C for 30 min. After cooling the
melt was boiled with MeOH and the insoluble residue was filtered
off and dissolved in CHCl3. The solution was filtered through a short
column packed with alumina (Merc 60, 70–2390 mesh). The final
purification was made on column packed with silica-gel (Merck 60,
70–230 mesh) using toluene/ethyl acetate (3:1) as eluent.
Light yellow crystals, 3.33 g, yield 76%, mp. 257–259 ◦C
(toluene/petrol ether 60–90).
2.1.2. 1,3-Diphenyl-6-triphenylmethyl-1H-pyrazolo[3,4-b]
quinoline 3a (Mol. 1)
In a round-bottomed flask aniline 1 (0.01 mol, 3.35 g) and 5-
chloro-1,3-diphenylpyrazolo-3-carbaldehyde 2a (0.01 mol, 2.82 g)
were heated together at 140–200 ◦C for 45 min. After cooling the
melt was boiled with MeOH and the insoluble residue was filtered
off and dissolved in CHCl3. The solution was filtered through a short
column packed with alumina (Merck 60, 70–230 mesh). The final
purification was made on column packed with silica-gel (Merck 60,
70–230 mesh) using toluene as eluent.
1H NMR(300 MHz, CDCl3, ı ppm): 8.41 (s, 1H, 4-H); 7.94 (d,
J = 9.2 Hz, 1H, 8-H); 7.85 (d, J = 2.3 Hz, 1H, 5-H); 7.51 (dd, J = 9.2 Hz,
2.3 Hz, 1H, 7-H); 7.33–7.24 (m, 15H); 4.67 (s, 3H, Me); 2.67 (s, 3H,
Me).
Yellow powder, 4.8 g, 84%, mp. 301–302 ◦C (toluene). Lit. [10]
301–302 ◦C.
H 5.63; N 9.33.
The investigate 1H-pyrazolo[3,4-b]quinolines 3 were prepared
by condensation of p-tritylaniline 1 with appropriate 5-chloro-4-
2.1.3. 1-Methyl-3-phenyl-6-triphenylmethyl-1H-pyrazolo
[3,4-b]quinoline 3b (Mol. 2)
In a round-bottomed flask aniline 1 (0.01 mol, 3.35 g) and 5-
chloro-3-methyl-1-phenyl pyrazolo-3-carbaldehyde 2b (0.01 mol,
2.20 g) were heated together at 140–200 ◦C for 35 min. After cooling
the melt was boiled with MeOH and the insoluble residue was fil-
tered off and dissolved in CHCl3. The solution was filtered through
a short column packed with alumina (Merck 60, 70–230 mesh).
The final purification was made on column packed with silica-gel
(Merck 60, 70–230 mesh) using toluene–ethyl acetate (3:1) as elu-
ent.
3. Results and discussion
In Fig. 1 presents the chemical formula of the investigated
molecule. They are differed by the substituted methyl and phenyl
groups. From this reason they should possess different ground state
dipole moments. Their UV–vis absorption spectra are presented in
Fig. 2. The spectral resolution of the obtained spectra is equal to
Yellow crystals, 3.9 g, 78%, mp. 275–276 ◦C (toluene/petrol ether
60–90). Lit. [10] 275–276 ◦C.