54
KESHTOV et al.
tometer and an SF2000 spectrofluorimeter. Photoluꢀ
minescence spectra were recorded on a Hitachi 850
spectrofluorimeter.
100
80
60
40
20
0
4,5ꢀDiazafluorenꢀ9ꢀone (I). 1,10ꢀPhenanthroline
(10.0 g, 55.0 mmol) and 10.0 g (180 mmol) of KOH
were dissolved in 750 mL of distilled water in a roundꢀ
bottom flask and heated to reflux. A hot solution of
25.0 g (160.0 mmol) of KMnO4 in 400 mL of water was
added to the mixture over 3 h. After stirring was comꢀ
plete, the mixture was heated at reflux for 10 min, and
then the precipitate was filtered off. The filtrate was
cooled to ambient temperature and extracted with
chloroform. The combined extracts were dried with
MgSO4 and concentrated by rotary evaporation. The
residue was recrystallized from acetone to give 5.5 g
(55%) of the title compound, mp 217–219°C.
2
1
200
400
600
800
T, °C
Fig. 3. TGA curves for polymer IVꢀ15 in (
1) air and
(2) argon.
1H NMR (CDCl3, 400 MHz, δН, ppm): 8.79 (d,
presence of electroluminescence bands in this region
is caused by the presence of fragments containing fluꢀ
orene in IVꢀ5. The nature of the broad band at 526 nm
is well known. It was shown that, on the one hand, it
can result from the presence of a small number of fluꢀ
orenone fragments as defects in the polymer chain
originated from their admixture in the initial fluorene,
and, on the other hand, it can be caused by the formaꢀ
tion of excimers between the fluorene fragments of the
polyfluorene [15].
2H,
7.6 Hz).
J 5.2 Hz), 7.94 (d, 2H, J 7.6 Hz), 7.32 (d, 2H, J
13C NMR (CDCl3, 100 MHz, δС, ppm): 189.5,
163.3, 155.1, 131.4, 129.1, 124.9.
For C11H6N2O anal. calcd. (%): C, 72.52; H, 3.32;
N, 15.38.
Found (%): C, 72.38; H, 3.32; N, 15.30.
4,5ꢀDiazaꢀ9,9'ꢀspirobifluorene (II). 4,5ꢀDiazafluꢀ
orenꢀ9ꢀone (I) (3.64 g, 20.0 mmol) and 100 mL of dry
In our case, it is obvious that the close packing of
the macromolecules of IVꢀ5 in solid lightꢀemitting
layer favors the formation of excimers during elecꢀ
troluminescence. The radiation resulting from the
relaxation of the excimers dominates in the emission
spectrum of the lightꢀemitting structure based on
IVꢀ5. Thus, the main channel of conversion of electriꢀ
cal energy into radiation is the formation of exciplex
states followed by their radiative relaxation.
THF were placed in a roundꢀbottom flask. 2ꢀBiphenyꢀ
lylmagnesium iodide preliminary prepared from 11.2 g
(40.0 mmol) of 2ꢀiodobiphenyl and 0.97 g
(40.0 mmol) of magnesium in diethyl ether was added
to the solution at reflux. The mixture was heated at
reflux for 12 h, cooled to ambient temperature, poured
into distilled water, and extracted with chloroform.
The organic extracts were dried with MgSO4 and conꢀ
centrated by rotary evaporation. The residue was
washed with hexane, dried, and dissolved in 500 mL of
acetic acid on heating. To the solution, 6 mL of sulfuꢀ
ric acid was added, and the mixture was heated at
reflux for 24 h, cooled to ambient temperature, poured
into water, and neutralized with aqueous NaOH soluꢀ
tion. The product was extracted with chloroform, and
the extract was dried with MgSO4 and concentrated by
rotary evaporation. The residue was washed with hexꢀ
ane to give light brown crystals. Yield 4.2 g (72%), mp
213–215°C.
EXPERIMENTAL
1H and 13C NMR spectra of the intermediate comꢀ
pounds and the polymers were recorded on a Bruker
Avanceꢀ400 spectrometer operating at 400.13 MHz
and 100.62 MHz, respectively. IR and Raman spectra
were recorded on a PerkinElmer 1720ꢀX Fourierꢀ
transform IR spectrophotometer, and TGA was perꢀ
formed with a PerkinElmer TGAꢀ7 analyzer at a heatꢀ
ing rate of 20 K/min. Molecular weight distribution
was analyzed by GPC using an Agilent 1100 liquid
chromatograph with a diode array UVꢀVis detection
system. Chromatography conditions: chloroform,
1H NMR (CDCl3, 400 MHz, δН, ppm): 8.75 (m,
2H), 7.88 (d, 2H,
7.08 (m, 6H), 6.74 (d, 2H,
J
6.8 Hz), 7.40–7.35 (m, 2H), 7.16–
6.8 Hz).
J
1 mL/min,
λ
= 380 nm. Calibration was made using
13C NMR (CDCl3, 100 MHz, δС, ppm): 158.2,
polystyrene standards. Absorption and electrolumiꢀ
nescence spectra of thinꢀfilm structures were recorded 149.7, 145.5, 143.2, 141.5, 131.2, 128.1, 127.8, 123.7,
with the use of a fiberꢀoptical PC2000 spectrophoꢀ 123.5, 120.3, 61.5.
DOKLADY CHEMISTRY Vol. 442
Part 2
2012