Synthesis and electrochemical properties of N-substituted bicarbazyl derivatives

Article abstract of DOI:10.1080/15421400490506090

N,N′-Diethyl-3,3′-bicarbazyl (DEBC)and N,N′-Diphenyl-3,3′-bicarbazyl (DPBC) was synthesized by the oxidative coupling reaction. The electrochemical properties of DEBC and DPBC were characterized by cyclic voltammetric technique. The oxidation of DEBC occu

Full text of DOI:10.1080/15421400490506090

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Synthesis and Electrochemical
Properties of N-Substituted
Bicarbazyl Derivatives
a
a
a
Yeong Kim , Young Kwon , Kwang Lee , Jong
a
b
c
Park , Hyeon Seo & Tae Kim
a
Department of Chemistry/Center for
Nanotechnology Research, The Catholic University,
Pucheon, Korea
b
Display Institute, Vistorm, Seongnam, Korea
c
Department of Physics, Hong-Ik University, Seoul,
Korea
Version of record first published: 18 Oct 2010.
To cite this article: Yeong Kim , Young Kwon , Kwang Lee , Jong Park , Hyeon Seo &
Tae Kim (2004): Synthesis and Electrochemical Properties of N-Substituted Bicarbazyl
Derivatives, Molecular Crystals and Liquid Crystals, 424:1, 153-158
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SYNTHESIS AND ELECTROCHEMICAL PROPERTIES
OF N-SUBSTITUTED BICARBAZYL DERIVATIVES
Yeong Eun Kim, Young Soon Kwon, Kwang Soon Lee,
and Jong Wook Park
Department of Chemistry=Center for Nanotechnology Research,
The Catholic University, Pucheon, 420-734, Korea
Hyeon Jin Seo
Display Institute, Vistorm, D503-2 Bundang Techno-Park,
Seongnam, 463-816, Korea
Tae Wan Kim
Department of Physics, Hong-Ik University, Seoul, 121-791, Korea
0
0
0
0
N,N -Diethyl-3,3 -bicarbazyl (DEBC) and N,N -Diphenyl-3,3 -bicarbazyl (DPBC)
was synthesized by the oxidative coupling reaction. The electrochemical
properties of DEBC and DPBC were characterized by cyclic voltammetric tech-
þ
nique. The oxidation of DEBC occurred at 0.56V and 0.8 V (vs. Ag=Ag ) and the
reduction also at 0.47 V and 0.72 V, where the carbazole unit might be oxidized
and coupled each other irreversibly to form the paired molecules of DEBC.
DPBC also showed the reversible oxidation at 0.74 V and 0.97 V and reduction
at 0.53 V and 0.77 V, respectively. The bandgap energy of DEBC and DPBC were
estimated to be 3.16 eV and 3.19 eV, respectively, according to each UV-Vis.
spectra.
Keywords: b an d ga p ; bic ar b az yl; cy cl ic vo lta mme try ; e lec tr ol umi ne sc en ce ; ox id ati on po te nti al
1. INTRODUCTION
S i n c e t he fi r st r e p or t o f mu lt il ay er h ig h ef f icie n c y or g an ic lig ht emit t in g
d i o de s ( OLE Ds ), t h er e h ave b ee n in t e n se r e sea r c h a ct iv it ie s in or g an ic
Rec eiv ed 1 Oc t ober 200 3; ac ce p t ed 30 De ce mbe r 200 3.
T h is wor k wa s sup p o r te d by g ra n t No. R01- 200 2-000- 00347-0 fr om th e i nte r di sci pl in ary
r es ea r c h p r ogr a m of th e KOS EF.
Ad d r ess c or r es p ond e n ce t o J on g Wook P ar k, De p ta r tm ent of Ch emi st ry=Ce nt er for N ano-
tec h n ol ogy Resea r c h , Th e Ca th olic Un iv er sit y, P u ch e on , 420- 734, Kor ea . Te l. : þ 82- 32- 340-
3
8 21 , Fa x : þ 8 2 - 3 2 -3 4 0 -3 7 6 4 , E -m ai l : h ah ap ark @c ath o l i c. ac.k r
153

1
5 4
Y. E. Kim et al.
e le c t r ol umi n e s c e n ce (E L ) d ev ice s [ 1] . Esp e c ial l y c ar b a zo le- co n t a in in g
c om pou nd s a r e wid e ly k no w n as an imp o r t ant c la ss of ma t er ia ls wh ic h
sh ow i nt r in s i c e le ct r o ni c p r op e r t ie s su ch as lu min esc en c e, h ole b l oc kin g
a n d ho le t ra n spo r t in g p r op e r t ie s [ 2– 4] .
We a lso ha v e be e n in t e r es te d in va r i o us ca r b a zol e b a sed d er iv a t iv es a s
we ll a s c a rb a z ol e b ip ol ar t yp es [ 5 ,6 ]. Re ce nt ly we syn t h esi zed n ew c ar b a -
0
0
0
zol e di me r mol e cu l es , N ,N - di et h yl- 3 ,3 - bi c a r b azy l (D E B C) a n d N ,N -
0
d ip he n y l -3, 3 -b i ca r b az yl (D PB C) , as go o d h ole t r a nsp o r t in g ma t er ia ls
wh i c h sh ow 20 % in cr e as ed EL ef f ici en cy r el a t iv e t o N PB in A lq syst em .
3
In he r e we fi r st ly r ep o r t t h e sy nt h esi s an d el ec t r oc h emi c al p r op er t ies of
DE BC a nd DPB C sin c e t h e el ec tr o ch e mic al st ab ili t y is a lso v er y imp or t a n t
is sue for l ife t i me in O LE D s.
2
2
. EXPERIMENTAL
.1. Materials and Characterization
Th e c y cl i c v ol t a mmo g r ams w er e r ec or d e d o n a c omp u t er c on t r oll ed E G & G
62 e l e c t ro ch e mic a l w or k st at io n in 0 .1 mo l =L t et r a ( n -b u t yl)a mmo n iu m
te tr a fl uo r ob or a te =ac et on i t r ile . Th e D EBC an d D PB C Film on a I TO
3
2
e le ct r od e wi th a n ar ea o f 1 cm , p r ep ar e d b y d r op c ast in g f r om sol ut ion
in c hl or of or m, w as u se d as t h e w o r k in g el ec t r od e. A p la t in u m wir e wa s
u s e d a s t he c ou n t er el ec t r o de an d a sil v er w ir e wa s u sed a s t h e r ef er e n c e
þ
e le ct r od e ( Ag =A g ). Th e se p ar a te d an o di c a n d c at h od i c sc an s we re
c a rr i e d ou t a t v a ri o us sc an r at e o f at r o om t em pe r a t u r e.
0 0
.2. Synthesis of N,N -Dsiphenyl-3,3 -bicarbazyl (DPBC)
2
0
0
N,N -Di ph e ny l -3 , 3 - bi c ar b az yl (D PBC) w as syn t h esi zed b y t h e ox id a t iv e
c oup l in g r e a ct i o n (se e S ch em e 1 ). To a 5 00 ml r ou n d f la sk wa r e p la c ed
Ir on ðjjjÞ c hl or i de (5 .3 5 g, 3 2. 9 6 mm o l) an d CH Cl (20 0 ml) u n d e r N . To t h is
3
2
mi xt ur e wa s a dd ed a so lu t io n o f 9 -p h en y l car b a zol e (2 g, 8.2 4 mmol ) in
c hl or o for m ( 100 m l) ve r y slo w ly. Th e mix t u r e w a s st ir r ed a t r oo m t emp er a -
tu r e for 4 hr. A fte r 1 0 % so di um h yd r o xi de so lut i o n wa s a d de d in t h e mix -
tu r e , t he a qu e o u s w as t h or o ug h ly ex t r ac t ed w it h c h lor of or m. Th e c r ud e
p ro du c t wa s di ss ol ve d in ch lo r o fo r m (1 0 ml) a n d r ep r ec ip i t a te d slo wly in
me t h a no l ( 20 0 ml) . Th e p r od u ct w as co ll ec te d b y f ilt r a t ion a n d d r ied u n d e r
v a cc u m a t r oo m t em p er a tu r e. (1 .0 3 g, 5 2 %).
1
H-N M R ( 30 0 M H z, CD Cl ) d 8 .4 6 ( s, 2 H) , 8.2 4 (d , 2H ) , 7.7 8 (d , 2H ) ,
3
7
.63 ( d, 8H) , 7. 5 0 ( t , 8 H) , 7 .3 3 ( t , 2 H) ; ma ss (p osi ti ve ion FA B) 48 4
ꢀ
þ
(M ) ; mp 20 0 C.

N-Substituted Bicarbazyl Derivatives
1
5
5
0
0
0
SCHEME 1 Sy nt h es is of (a ) N ,N - D iet h y l- 3,3 - b ic ar b a zy l (D E B C ) a n d (b ) N ,N -
0
D ip he ny l- 3,3 - b ica r ba zy l (D P B C ).
0 0
.2. Synthesis of N,N -Diethyl-3,3 -bicarbazyl (DEBC)
2
0
0
N,N -Di e t hy l -3 ,3 - bi ca rb az yl (D EBC ) w as sy n t h esize d b y sa me p r oc ess wit h
DPB C ( se e Sc h e m e 1 ) (2 .5 g, 8 3 %).
1
H
-
N
M
R
(
3
0
0
M
H
z
,
C
D
C
l
)
d
8
.
4
2
(
s
,
2
H
)
,
8
.
1
9
(
d
,
2
H
)
,
7
.
8
4
(
t
,
2
H
)
,
3
7
.5 1 ꢁ 7. 41 ( m, 6H ), 7 .2 5 ( t , 2 H), 4 .4 1 (q , 4 H) 1.4 7 ( t , 6H ) ; ma ss (p osi ti ve
þ
ꢀ
io n FA B) 38 8 ( M ); mp 1 89 C.
. RESULT AND DISCUSSION
We ha v e sy nt he s ize d t wo ca r ba zo le d ime r d er iv a t iv es, N ,N -D i et h yl- 3,3 -
3
0
0
0
0
b i c a rb a zy l ( DEB C ) an d N ,N - Di p h en yl -3 ,3 - bi ca r b a zyl (D PBC) , wh ic h h a s
g e ne r a l ly t he hi g h h ol e mo bi lit y an d is u sed f or h ole t r a nsp o r t a ti on in
o rg a n i c se mi c ond u c t in g d ev ice su ch as el ec t r olu mi n esc en c e (E L ) d ev ic e
a nd sol a r c e l l .
DE BC a nd DP B C w er e sy nt h esi ze d b y u sin g c ou p lin g r ea c ti on a t r oo m
te m pe r a t ur e ( se e S ch em e 1 ). Th ese t wo p r o du ct s we re f in a lly p u r if ied wit h
a p pr op r ia t e sol v e n t an d r ep r e c ip it a te d t o h ave hi gh ly p u r e b eige c olor p ow-
d e r. Th e st r uc t ur e w as id e nt if ie d b y N M R, UV- Vis. sp ec t r osc op ie s a n d D S C.
Th e r e su l ti ng p r od u ct s ar e so lu b le in co mmo n sol ven t su c h a s c h lor o-
fo r m a nd THF. T he D EBC an d D PBC f ilms d o n ot sh ow a n y p a r ti c le on
th e su r fa c e a nd e x hi b it ed a smo ot h su r fa ce w he r e ob ser v ed b y mic r osc o p e.
M e a nw hi le , a lt ho u gh N -su b st it u t ed ca r ba zo le ( mon o u n i t ) b ef or e c ou p lin g
ꢀ
ꢀ
r e a c ti on sh ow s l ow m el t in g t emp er a t ur e at ar ou n d 74 C, t h e D EB C a n d
ꢀ
DPB C sh ow hi g h m el t in g t em p er a tu r e at 1 89 C a n d 20 0 C.
In U V sp e ct r os co p ies , t h e D EBC an d D PB C sh ow ed simil ar a b so r p t ion
sp e c tr a wi th t he sa me UV ab so r p t io n max i mu m v al ue a t a b o u t 35 3 n m.

1
5 6
Y. E. Kim et al.
Th e ba n dg a p e ne r gy o f D EBC an d D PB C ar e est ima t ed t o b e 3.1 6 eV a n d
.1 9 e V fr om t he an al ysi s o f t h e ab so r p ti on e d ge wit h a p lot of ( hv) v s.
3
2
(
fr e q ue n c y of l ig h t , r es pe ct iv ely.
ahv) , wh e r e a, h, and v ar e ab so r b an ce , Pla n k’s c on st a n t, a n d t h e
To i nv e s t ig a te el ec t r o ch emi ca l k in et ic b eh av io r, t h e mea su r ed c yc lic v ol-
ta mmog r a ms of D EBC an d D PBC w it h t h e v ar i ou s sc an r a t es (20 mV =s
ꢁ
2 00 mV =s) a r e sh ow n Fig u r es 1 an d 2 . Th e pe a k p ot en t ia ls a r e gr a d u al ly
sh i ft e d t o hi g he r p ot e nt ia ls as t h e sc an r at e is in c r ea s ed . A lso we h a ve
o bse r v e d v e r y sta bl e cy cl i c vo lt ammo g r ams o f D EB C a n d D PB C wit h t h e
c on se c ut i ve sc a n (u p t o 1 00 cy cl e s) in d ic at in g t h ese t wo ma t er ia ls h a ve
r el a ti v e l y st a ble r ed o x p r oc ess.
In Fi g ur e 1, t h e o xi da t io n o f D EBC o ccu r r ed a t 0.5 6 V a n d 0.8 V
þ
(
v s. A g =A g ) an d t h e r ed u ct i o n al so at 0 .4 7 V a n d 0.7 2 V, wh er e t h e c ar b a -
zo l e un i t mi g ht be o x id iz ed an d co u pl ed ea ch ot h er ir r ev er sib ly t o f or m t h e
p ai r e d mol e c ul e s o f D E BC in t h e f ir st sc an [ 7]. Th e D PB C a lso sh ow s t h e
r e v er s ib l e ox id a t io n at 0 .7 4 V an d 0 .9 7 V an d r ed u c t i on a t 0.5 3 V a n d
0
.77 V, r e sp e c t iv e ly.
Th e r e do x c ur r en t va lu e gr a d ua lly in c r ea sed a s t h e sc an r a t e in c r ea sed .
Th i s r e su lt su g g es t s t h at t h e el ec t r o ch emi ca l p r oc esse s of D EB C a n d D PB C
þ
a re r e pr od uc i bl e in t h e p ot e nt ia l r an ge o f 0 ꢁ2 V v s. A g =A g .
It ha s be e n r ep o r t ed t h at t h e r el at io n sh ip b et wee n t h e r ed ox p ea k
c u r re nt a nd t he sc an r at e ca n b e ex p r es sed as a p owe r la w t yp e a s f ollo w s:
[
7 ,8 ]
x
ip;a ¼ kv
lo g ip;a ¼ lo g k þ x lo g v
ð1 Þ
ð2 Þ
wh e r e ip;a ¼ ox id at io n p ea k cu r r en t d en sit y, v ¼ sc an r a t e, k ¼ p r op o r-
tion a l c ons ta n t , a n d x ¼ ex p o ne n t o f sc an r at e .
A ssu mi ng t ha t el ec t r o de k in et ic s sa ti sfi es Eq . (1) , t h e ele ct r oc h emi c al
r ed ox r e a ct i o n on t h e el ec tr o d e is co n t r ol led b y eit h e r t h e ele ct r on t r a nsf e r
FIGURE 1 C yc lic v olt am m og r a ms of D E B C w it h v a r iou s s c a n r a t e (0.1 M
(n - B u)
4 4
NB F =A ce ton it r ile ). (a ) 20 m V=s e c (b ) 50 m V=s e c (c ) 100 m V=s e c (d )
200 m =V s ec .

N-Substituted Bicarbazyl Derivatives
157
FIGURE 2 C yc lic v olt am m og r a ms of D P B C w it h v a r iou s s c a n r a t e (0.1 M
n - B u) NB F =A ce to n itr ile ). (a ) 20 m V=s e c (b ) 50 m V=s e c (c ) 100 m V =s e c (d )
00 m =V s ec .
(
4
4
2
p r o ce s s, wh e re x ¼ 1 , o r t h e r ea ct a n t d if fu s ion p r oc es s, wh er e x ¼ 0.5
7 , 9] .
R el a t i ons sa t is fy i n g Eq . (2 ) b et w een t h e ox id a t ion c u r r en t d en s it y
l og ip;a) a nd t he sc an r at e (l og v) ar e sh ow n in Figu r e 3.
Th e ox id a ti on c u r re n t d en sit y o f D EBC an d DPBC v er su s t h e sc an r a t e is
[
(
a p pr ox ima t e l y l ine a r r el at io n sh ip in t h e r an ge of 20 ꢁ 20 0 mV =sec . Th e
e xp o ne n t of sc a n r at e , x, va lu es o f D EBC ar e f ou n d t o b e 0.2 8 a n d 0.2 7
FIGURE 3 P lot of log ip, a v s . log v for (a ) D E B C a n d (b ) D P B C .

1
5 8
Y. E. Kim et al.
a n d t he x v a lu e s o f D PB C ar e 0 .2 3 an d 0 .2 4, r esp ec t iv ely. Th ese v al ue s a r e
sm a ll e r t ha n t he o ne o f el ec t r oa ct i ve m at e r ial s.
Fu r th e r st ud ie s o n sy nt h esi s an d el ec t r o- o pt ic a l p r op er t ies of d imer a n d
tr im er a r e un de r w ay.
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