Dispirocycles: Platforms for the Construction of High-Performance Host Materials for Phosphorescent Organic Light-Emitting Diodes

Article abstract of DOI:10.1002/chem.201806207

Spirocyclic compounds such as 9,9′-spirobifluorene (SBF) are becoming more and more attractive for use as host materials in organic optoelectronic devices. Herein, two dispirocycles, namely, dispiro[fluorene-9,9′-anthracene-10′,9′′-fluorene] and 10,10′′-diphenyl-10H,10′′H-dispiro[acridine-9,9′-anthracene-10′,9′′-acridine], were used for the construction of host materials 1–4. The attached triphenylamino group determines the thermal, photophysical, electrochemical, and charge-transport properties, and therefore they have different electroluminescent performances. The device based on dispiro[fluorene-9,9′-anthracene-10′,9′′-fluorene] (2) and 10,10′′-diphenyl-10H,10′′H-dispiro[acridine-9,9′-anthracene-10′,9′′-acridine] (3) molecular platforms exhibited external quantum efficiencies of greater than 21 % with a very high power efficiency (≈100 lm W^?1). These results demonstrate the potential of extending the application of dispirocyclic molecular platforms with inherent rigidity for developing highly efficient host materials for organic light-emitting diodes.

Full text of DOI:10.1002/chem.201806207

A Journal of
Accepted Article
Title: Dispirocycles: Novel Platforms for Construction of High-
Performance Host Materials for Phosphorescent Organic Light-
Emitting Diodes
Authors: Jian Fan, Xiang-Yang Liu, Yi-Jie Zhang, Xiyu Fei, and Man-
Keung Fung
This manuscript has been accepted after peer review and appears as an
Accepted Article online prior to editing, proofing, and formal publication
of the final Version of Record (VoR). This work is currently citable by
using the Digital Object Identifier (DOI) given below. The VoR will be
published online in Early View as soon as possible and may be different
to this Accepted Article as a result of editing. Readers should obtain
the VoR from the journal website shown below when it is published
to ensure accuracy of information. The authors are responsible for the
content of this Accepted Article.
To be cited as: Chem. Eur. J. 10.1002/chem.201806207
Link to VoR: http://dx.doi.org/10.1002/chem.201806207
Supported by

10.1002/chem.201806207
Chemistry - A European Journal
DOI: 10.1002/((please add manuscript number))
Article type: Full Paper
Dispirocycles: Novel Platforms for Construction of High-Performance Host Materials for
Phosphorescent Organic Light-Emitting Diodes
Xiang-Yang Liu,† Yi-Jie Zhang,† Xiyu Fei, Man-Keung Fung,* and Jian Fan*
Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Joint International
Research Laboratory of Carbon-Based Functional Materials and Devices, Institute of
Functional Nano & Soft Materials (FUNSOM), Soochow University, Suzhou, Jiangsu 215123,
China
† The two authors contribute equally to this paper.
E-mail: mkfung@suda.edu.cn (Prof. M.-K. Fung); jianfan@suda.edu.cn (Prof. J. Fan).
Keywords: (Dispirocycles, Host materials, Phosphorescence, OLEDs, Triplet energy)
Abstract: Spirocycle compounds such as 9,9′-Spirobifluorene (SBF) are becoming more and
more attractive for use as the host materials in organic optoelectronic devices. In this manuscript,
two dispirocycles, namely dispiro[fluorene-9,9ʹ-anthracene-10ʹ,9ʹʹ-fluorene] and 10,10ʹʹ-
diphenyl-10H,10ʹʹH-dispiro[acridine-9,9ʹ-anthracene-10ʹ,9ʹʹ-acridine] were used for the
construction of hosts materials (1, 2, 3, and 4). The attached triphenylamine group would
determine the thermal, photophysical, electrochemical, and charge transport properties, and
therefore they have different electroluminescence performances. The device based on
dispiro[fluorene-9,9ʹ-anthracene-10ʹ,9ʹʹ-fluorene] (2) and 10,10ʹʹ-diphenyl-10H,10ʹʹH-
dispiro[acridine-9,9ʹ-anthracene-10ʹ,9ʹʹ-acridine] (3) molecular platforms exhibited a external
quantum efficiency of over 21% with a very high power efficiency (~100 lm W-1). The results
here demonstrate to us the potential of extending the possibilities of applying the dispirocyclic
molecular platforms with inherent rigidity for developing highly efficient host materials for
OLEDs.
1
This article is protected by copyright. All rights reserved.

10.1002/chem.201806207
Chemistry - A European Journal
Since 9,9′-Spirobifluorene (SBF) was first reported in 1930,[1] it has attracted considerable
attention and has been successfully applied in various fields[2-12] such as asymmetric catalysts,[2]
macrocyclic sensors,[3] self-assembling structures,[4] porous materials,[5] and organic
electronics.[6-12] It is well known that there are four isomeric mono-substituted SBF derivatives
(Figure 1), and their synthesis methods are well established.[13-16] So far the most common di-
substituted SBF derivatives are the compounds with substituents at the 2,7-positions or 3,6-
positions. From a chemist’s point of view, the symmetrically 2,7-[17] or 3,6-[18] substituted SBF
and asymmetrically 2,2ʹ-, or 3,3ʹ-substituted SBF[19] can be facilely prepared relative to other
di-substituted SBF derivatives. For the tetra-substituted compounds, the 2,2ʹ,7,7ʹ-
tetrasubstituted SBF are positioned along two perpendicular axes while 3,3ʹ,6,6ʹ-
tetrasubstituted SBF reveals a tetrahedral orientation. When the two substituents (R1 and R2)
are located on different fluorene motifs, the di-substituted SBF molecular are chiral (axial
chirality) and it does not matter whether R1 = R2 or R1 ≠ R2.[20,21] Compared to 2,7-[17] or 3,6-
[18]
substituted SBF, the straightforward and efficient synthesis methods of 1,8- and 4,5-
disubstituted SBF derivatives are still highly desirable.[22,23] So far, a plethora of synthetic
methods have been developed for the functionalization of SBF.[15a,24] From a synthetic point of
view, the functionalization of SBF can be accomplished after the SBF core is available or with
decoration of the fluorone motif and the related precursors at an early stage.[25-28] For example,
the symmetric 2,2ʹ,7,7ʹ-substituted SBF can be prepared with tetra-halogenated (bromide or
iodide) SBF precursors.[21,25,26]
Recently, SBF derivatives are gaining increasing interest in the research area of organic
electronics,[14-16,29] and many novel spirocycles with various levels of structural diversity have
been developed in the pursuit of high performance of electronic devices. In addition, modern
synthetic methodology allows the molecular fragments and functional groups to be manipulated
in many innovative ways which promotes the discovery of novel materials. Much research
effort has concentrated on the development of highly efficient OLEDs materials,[30-35] and a
variety of SBF analogues (Figure 2) have been used as novel molecular platforms. In particular,
several dispiro-compounds have been reported and applied to efficient OLEDs (Figure 3).[36-40]
For instance, Poriel, et al., reported a series of dispirofluorene–indenofluorene (DSF-IF)
isomers, which were used as high efficiency OLEDs materials.[36] So far, the application of
dispiro[fluorene-9,9ʹ-anthracene-10ʹ,9ʹʹ-fluorene]
(DSFA)
and
dispiro[acridine-9,9ʹ-
anthracene-10ʹ,9ʹʹ-acridine] (DSAA) derivatives as host material has been rarely reported.
Herein, we designed and synthesized four novel dispirocyclic compounds, 2ʹ-(tert-
butyl)dispiro[fluorene-9,9ʹ-anthracene-10ʹ,9ʹʹ-fluorene]
(1),
4-(dispiro[fluorene-9,9ʹ-
2
This article is protected by copyright. All rights reserved.

10.1002/chem.201806207
Chemistry - A European Journal
anthracene-10ʹ,9ʹʹ-fluoren]-2ʹ-yl)-N,N-diphenylaniline (2), 4-(10,10ʹʹ-diphenyl-10H,10ʹʹH-
dispiro[acridine-9,9ʹ-anthracene-10ʹ,9ʹʹ-acridin]-2ʹ-yl)-N,N-diphenylaniline (3), and 2ʹ-(tert-
butyl)-10,10ʹʹ-diphenyl-10H,10ʹʹH-dispiro[acridine-9,9ʹ-anthracene-10ʹ,9ʹʹ-acridine] (4). The
thermal stabilities, photophysical properties, and electrochemical behaviors of these four
compounds were investigated systematically. The electron-donating group, triphenylamine,
was introduced to tune the charge transport capability. The device performance of these
compounds was studied as host material. The OLED devices hosted by 2 and 3 with bis(2-
phenylpyridine) (acetylacetonate)iridium (III) (Ir(ppy)2(acac)) as a green dopant exhibited a
device performance with a maximum external quantum efficiency of over 21%. It is worth
noting that the power efficiencies of 2- and 3-based devices reached about 100 lm W-1, which
would encourage us to pursue a further investigation based on dispiro compounds.
The synthetic routes of 1, 2, 3, and 4 as illustrated in Scheme 1. 2-(tert-butyl)anthracene-9,10-
dione and 2-bromoanthracene-9,10-dione were treated with 2-lithiumbiphenyl or (2-
(diphenylamino)phenyl)lithium to obtain the corresponding tertiary alcohols, and the acid
catalyzed cyclization reaction yields 1, 2a, 3a, and 4.[38a,41] The products of 2 and 3 can be
obtained through the Suzuki−Miyaura C−C coupling reaction between the respective dispiro
compounds 2a and 3a and (4-(diphenylamino)phenyl)boronic acid with good yields. The
structures of the target products were fully characterized by 1H/13C NMR spectroscopy, mass
spectrometry (MS) and elemental analysis (EA).
As shown in Figure 4 and Figure 5, the thermal properties of 1, 2, 3, and 4 were examined via
differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) under a
nitrogen atmosphere. The corresponding glass transition temperatures (Tg)/ crystallization
temperatures (Tc)/ melting point (Tm)/ decomposition temperatures (Td, 5 wt% weight loss) of
o
o
o
1, 2, 3, and 4 were -/-/351/334 C, -/-/333/438 C, 132/230/-/490 C, and 134/-/392/396 oC,
respectively (Table 1). It is worth noting that the Tg values of 1 and 2 were not observed. On
the other hand, the nearly 100% weight loss of 1, 2, and 4 at above 400 oC could be due to
sublimation, which suggests that these spirans are stabilized at those temperatures and can be
thermally deposited for device fabrication.
Room temperature ultraviolet-visible (UV-Vis) absorption and photoluminescence (PL) spectra
and low temperature (77 K) phosphorescence (Phos) spectra of 1, 2, 3, and 4 were measured in
toluene. As shown in Figure 6, 1 and 2 give well-defined absorption peaks at around 300/311
3
This article is protected by copyright. All rights reserved.

10.1002/chem.201806207
Chemistry - A European Journal
nm and 300/311/337 nm, respectively. In contrast, 3 and 4 show broad and structureless
absorption and maximum absorption peaks at around 323 nm and 310 nm, respectively, which
might be due to the relatively flexible structures of 3 and 4. Moreover, the absorption band in
the range of 320-370 nm for compound 2 could arise from the triphenylamine segment. The
absorption onsets of 1, 2, 3, and 4 are 316 nm, 370 nm, 370 nm, and 340 nm, respectively.
Therefore, the corresponding optical energy gaps (Egs) of 1, 2, 3, and 4 were estimated to be
3.92 eV, 3.35 eV, 3.35 eV, and 3.63 eV, respectively. The introduction of the triphenylamine
unit led to a conspicuous red-shift in 2 and 3 in comparison with 1 and 4. As shown by the PL
curves, compound 1 exhibited well-defined emission with peaks at 316 nm and 327 nm, and 2-
4 compounds showed structureless spectra with peaks at 385 nm, 385 nm, and 348 nm,
respectively. For compounds 1, 4 and 3, their PL emission peaks are red-shifted gradually with
the increase in the number of electron-donating group triphenylamine. All these compounds
exhibited well-defined Phos emission curves and the corresponding triplet energies (ETs) can
be calculated by the highest vibronic band of 1 (434 nm), 2 (482 nm), 3 (481 nm), and 4 (408
nm), which are 2.86 eV, 2.57 eV, 2.58 eV, and 3.04 eV, respectively. So these four compounds
can be used as host material for green PHOLEDs.
It is worth noting that 2 and 3 show nearly identical PL spectra and quite similar Phos spectra,
so they have similar lowest singlet (S1) and triplet (T1) excited states. In order to gain more
insights into the excited state characteristics of 1, 2, 3, and 4, natural transition orbitals (NTOs)
were used to describe their S1 and T1 excitations.[42] The NTO (hole and particle) distributions
and the weight of hole-particle contribution to S1 and T1 are shown in Figure 7. The holes of S1
of 1 are mainly distributed on the fluorene unit and one phenyl group of 9,10-dihydroanthracene
fragment. The corresponding particles, however, are primarily limited to the fluorene unit. In
compound 4, the holes and particles of S1 are mainly localized on the 9,10-dihydroacridine and
N-phenyl group, respectively. It is worth noting that the holes and particles of the S1 states of 2
and 3 have essentially the same distributions, namely, the holes are mainly localized on the
diphenylamine units and the particles are primarily dispersed along the biphenyl segments (one
phenyl group comes from triphenylamine and the other from 9,10-dihydroanthracene).
Considering the similar molecular structures and similar S1 characteristics observed in 2 and 3,
it is not surprising that these two compounds have essentially identical PL spectra. In addition,
the S1 states of compound 1 feature a local excitation (LE) character and the S1 states of the
other three compounds exhibit a charge-transfer (CT) excitation character, which agrees well
with the shape of their PL curves. The distributions of holes and particles of T1 in 1 and 4 are
4
This article is protected by copyright. All rights reserved.

10.1002/chem.201806207
Chemistry - A European Journal
confined to the fluorene and 9,10-dihydroacridine segments, respectively. On the other hand,
the distributions of T1 holes and particles in 2 and 3 are mainly confined to the biphenyl
fragment, which could explain their similar ET values. As a result, the holes and particles of T1
of 1-4 are mainly located on the same fragment in each compound, indicating the LE character,
which is consistent with their well-defined Phos emissions.
The electrochemical behaviors of 1, 2, 3, and 4 were further investigated by cyclic voltammetry
(CV) measurement in dichloromethane solution. The cyclic voltammograms are shown in
Figure 8 and the detailed results are summarized in Table 1. 1, 2, 3, and 4 show the oxidation
processes during the anodic scan, and the corresponding onsets of the first oxidation waves
were 1.44 V, 0.85 V, 0.86 V, and 0.96 V. Therefore, the highest occupied molecular orbitals
(HOMO) energy levels are estimated to be -5.82 eV, -5.23 eV, -5.24 eV, and -5.34 eV,
respectively. On the other hand, the lowest unoccupied molecular orbitals (LUMO) energy
levels of 1, 2, 3, and 4 can be calculated by their Egs and the corresponding HOMO energy
levels, which are -1.90 eV, -1.80 eV, -1.89 eV, and -1.71 eV, respectively. Furthermore, to
better understand the relationship between molecular structure and electronic structure, density
function theory (DFT) calculations are carried out to simulate the HOMO/LUMO distributions
and energy levels and the optimized geometry of 1, 2, 3, and 4 at a B3LYP/6-31G(d) level
(Figure 9). As shown in Figure 9, the HOMO distributions of 1, 2, 3, and 4 are quite different.
Since there is no strong electron-donating group in 1, the HOMO of compound 1 is distributed
over the whole molecule. For 2 and 3, the HOMOs are localized at the triphenylamine segments
and extended partially over one phenyl group of the 9,10-dihydroanthracene unit. As for
compound 4, the HOMO is mainly distributed on the 9,10-dihydroacridine unit. It is worth
noting that compounds 2 and 3 have similar HOMO energy levels due to their similar HOMO
contribution unit. Meanwhile, the LUMO distributions of 1, 2, 3, and 4 are also quite different.
The LUMOs are mainly localized in the fluorene parts for 1 and 2, and two phenyl groups (one
from triphenylamine and the other from 9,10-dihydroanthracene) for 3. However, the LUMO
of 4 are spread over the whole backbone. So the similar LUMO distributions of 1 and 2 led to
a small difference in their LUMO energy levels. The introduction of the electron-donating
triphenylamine group into the skeletons of 2, 3 and 4 results in their shallow HOMO energy
levels. These results match well with the experimental (CV) data.
To study the capability of these four dispirocycles (1, 2, 3, and 4) as host material in PHOLEDs,
green devices were fabricated with Ir(ppy)2(acac) as dopant. The device structure is described
5
This article is protected by copyright. All rights reserved.

10.1002/chem.201806207
Chemistry - A European Journal
as follows: ITO/ HAT-CN (10 nm)/ TAPC (55 nm)/ Host: 10 wt% Ir(ppy)2(acac) (20 nm)/
B4PyMPM (40 nm)/ Liq (2 nm)/ Al (120 nm). The current density–voltage–luminance (J–V–
L) characteristics, current efficiency (CE)/power efficiency (PE)/external quantum efficiency
(EQE) versus L plots, and electroluminescent (EL) spectra as depicted in Figure 10, and the
detailed parameters are summarized in Table 2.
As shown by the J–V–L characteristics curves (Figure 10(a)), all four devices exhibited
relatively low driving voltages at a luminance of 200 cd m-2 with 3.24 V for 1, 2.47 V for 2,
2.53 V for 3 and 2.65 V for 4, indicating that the introduction of the electron-donating
triphenylamine group can improve the hole transport properties of the host materials, no matter
whether a triphenylamine motif was involved in th backbone (3 and 4) or acting as a side chain
(2). Furthermore, the hole- and electron-transport performance of these materials was further
studied with hole-only and electron-only devices: ITO/MoO3 (10 nm)/1, 2, 3, or 4 (100
nm)/MoO3 (10 nm)/Al (100 nm) (hole-only devices) and ITO/TmPyPB (20 nm)/1, 2, 3, or 4
(100 nm)/TmPyPB (20 nm)/Liq (2 nm)/Al (100 nm) (electron-only devices). The J–V
characteristics of single carrier devices are presented in Figure 11. As expected, 1, 2, 3, and 4
are typical unipolar materials, their hole transport abilities are significantly better than their
corresponding electron transport abilities. In addition, 2, 3, and 4 demonstrate similar hole-
/electron-transport properties, but superior to 1, which could account in part for the trend of
their device driving voltages.
Figure 10(b) gives the device efficiencies based on 1-4, labeled as G1-G4. All of the devices
displayed a satisfactory device performance. The device based on 2 (G2) achieved the highest
device performance among G1-G4 with a maximum CE and EQE of 78.0 cd A-1 and 21.7%,
respectively. On the other hand, the device using 3 as the host material (G3) also obtained a
high device efficiency with a maximum CE of 76.0 cd A-1 and EQE of 21.3%. It is worth noting
that the PEs of G2 and G3 are as high as 100.5 lm W-1 and 96.1 lm W-1, respectively, which are
comparable to the state-of-the-art results based on Ir(ppy)2(acac).[43] The maximum CE, PE,
and EQE of device G4 (hosted by 4) are 65.0 cd A-1, 80.0 lm W-1, and 18.3%, respectively.
However, the device performance of G1 (hosted by 1) is relatively lower than that of G2-G4,
and the maximum CE, PE and EQE are 57.0 cd A-1, 59.5 lm W-1, and 16.0%, respectively. The
remarkable performance of G2 might be attributed to its high ET and good charge transport
capacity.[44] The high ET could favor the energy transfer process from the host to the dopant and
block the energy transfer process from the dopant back to the host since no other emission was
observed from the EL spectra. On the other hand, the good charge transport ability may decrease
the driving voltage and lead to a high PE value. The EL spectra of devices G1-G4 are shown in
6
This article is protected by copyright. All rights reserved.

10.1002/chem.201806207
Chemistry - A European Journal
Figure 10(c). All of the devices exhibit a typical Ir(ppy)2(acac) emission with a peak at 520 nm,
which means the triplet excitons are confined efficiently in the dopant. The CIE coordinates of
G1-G4 at a current density of 5 mA cm-2 are (0.33, 0.63), (0.34, 0.62), (0.33, 0.63), and (0.33,
0.63), respectively. The tiny difference in the CIE coordinates might be ascribed to the
distribution variation of the dopant in the emission layer (EML), which results in the diversity
of the emission zone (EMZ).[45]
In this study, two types of dispirocyclic compounds, namely dispiro[fluorene-9,9ʹ-anthracene-
10ʹ,9ʹʹ-fluorene] (DSFA) and dispiro[acridine-9,9ʹ-anthracene-10ʹ,9ʹʹ-acridine] (DSAA), were
used to construct host materials (1, 2, 3, and 4) for green PHOLEDs. The preparation,
characterization, and basic photophysical/electrochemical/EL properties of four new hosts were
studied in detail. The variation in their molecular configuration has a profound effect on their
basic physical, charge transport, and EL properties. The device based on 2 containing DSFA
has the best device performance with a PE of over 100 lm W-1 among the four OLEDs, G1-G4.
In addition, the device hosted by 3 containing DSAA also showed a high PE of 96.1 lm W-1.
This study will pave the way for the developing of highly efficient host materials using these
dispirocycles as molecular platforms.
Materials Synthesis
Compound 2ʹ-bromodispiro[fluorene-9,9ʹ-anthracene-10ʹ,9ʹʹ-fluorene] (2a) was prepared
according to the previous literature.[41] Compounds 2ʹ-(tert-butyl)dispiro[fluorene-9,9ʹ-
anthracene-10ʹ,9ʹʹ-fluorene] (1), 2ʹ-bromo-10,10ʹʹ-diphenyl-10H,10ʹʹH-dispiro[acridine-9,9ʹ-
anthracene-10ʹ,9ʹʹ-acridine]
(3a),
and
2ʹ-(tert-butyl)-10,10ʹʹ-diphenyl-10H,10ʹʹH-
dispiro[acridine-9,9ʹ-anthracene-10ʹ,9ʹʹ-acridi-ne] (4) were synthesized according to the
reported procedure.[38a,41]
Preparation of 1, 3a, and 4
1, white solid. 1H NMR (600 MHz, Methylene Chloride-d2): δ = 7.96 (d, J = 7.7 Hz, 4H), 7.45
(t, J = 7.5 Hz, 4H), 7.31 (q, J = 7.4 Hz, 4H), 7.24 (t, J = 8.4 Hz, 4H), 6.84 (d, J = 8.5 Hz, 1H),
6.81 – 6.76 (m, 2H), 6.43 – 6.35 (m, 3H), 6.29 (d, J = 8.5 Hz, 1H), 0.89 (s, 9H) ppm. 13C NMR
(151 MHz, Methylene Chloride-d2): δ = 157.32 (d, J = 13.8 Hz), 149.28, 140.52, 136.90, 136.70,
135.87, 133.36, 128.69 (d, J = 13.3 Hz), 128.34 (d, J = 7.4 Hz), 127.86, 127.48 (d, J = 13.5 Hz),
126.62 (d, J = 3.9 Hz), 125.20 (d, J = 4.8 Hz), 124.10, 120.15 (d, J = 17.5 Hz), 58.11, 57.67,
7
This article is protected by copyright. All rights reserved.

10.1002/chem.201806207
Chemistry - A European Journal
33.88, 30.50 ppm. MALDI-TOF-MS: m/z: calcd for C42H32: 536.718, found: 536.564. Anal.
Calcd for C42H32 (%): C 93.99, H 6.01; found: C 94.04, H 6.13.
3a, white solid. 1H NMR (400 MHz, Chloroform-d): δ = 7.81 (s, 1H), 7.79 – 7.74 (m, 4H), 7.65
– 7.57 (m, 4H), 7.54 (d, J = 7.7 Hz, 3H), 7.48 – 7.42 (m, 1H), 7.35 (d, J = 8.6 Hz, 1H), 7.15 (d,
J = 8.6 Hz, 1H), 7.06 (td, J = 7.4, 1.8 Hz, 2H), 7.01 – 6.92 (m, 4H), 6.89 (d, J = 7.8 Hz, 4H),
6.74 (dt, J = 10.4, 7.5 Hz, 4H), 6.43 (dd, J = 15.5, 8.3 Hz, 4H) ppm. MALDI-TOF-MS: m/z:
calcd for C50H33BrN2: 741.732, found: 741.538. Anal. Calcd for C50H33BrN2 (%): C 80.97, H
4.48, N 3.78; found: C 81.03, H 4.50, N 3.72.
4, white solid. 1H NMR (600 MHz, Chloroform-d): δ = 7.73 (t, J = 7.7 Hz, 4H), 7.62 – 7.54 (m,
6H), 7.53 – 7.49 (m, 2H), 7.48 (d, J = 2.2 Hz, 1H), 7.37 (d, J = 8.4 Hz, 1H), 7.08 – 6.99 (m,
3H), 6.95 – 6.87 (m, 8H), 6.74 – 6.63 (m, 4H), 6.43 – 6.36 (m, 4H), 1.12 (s, 9H) ppm. 13C NMR
(151 MHz, Chloroform-d): δ = 149.11, 143.44, 143.07, 142.65, 141.56, 141.37, 140.19 (d, J =
8.3 Hz), 139.81, 131.98 (d, J = 10.8 Hz), 131.76, 131.26 (d, J = 5.3 Hz), 131.00, 130.52, 130.18,
128.31 (d, J = 7.9 Hz), 127.39, 126.76 (d, J = 10.2 Hz), 126.46 (d, J = 11.2 Hz), 124.26, 120.44
(d, J = 5.7 Hz), 114.41 (d, J = 8.5 Hz), 49.22, 48.71, 34.26, 31.14 ppm. MALDI-TOF-MS: m/z:
calcd for C54H42N2: 718.944, found: 718.878. Anal. Calcd for C54H42N2 (%): C 90.21, H 5.89,
N 3.90; found: C 90.28, H 5.92, N 3.96.
Preparation of 2 and 3
2a (2 g, 3.6 mmol), (4-(diphenylamino)phenyl)boronic acid (1.25 g, 4.3 mmol), potassium
carbonate (K2CO3) (1 g, 7.2 mmol), and tetrakis(triphenylphosphine) palladium(0) (Pd(PPh3)4)
(0.16 g, 0.14 mmol) were added into 1,4-dioxane (100 mL) under argon before the addition of
o
water (10 mL). The resulting solution was heated at 95 C overnight. After cooling down to
room temperature, the product was extracted with dichloromethane for three times. The organic
layer was collected, dried over (anhydrous sodium sulfate, Na2SO4), and evaporated. The crude
product was subjected to column chromatography (petroleum ether/dichloromethane: 4/1, V/V)
1
to obtain 2 as a white powder (yield: 2.3 g, 87%). H NMR (600 MHz, Methylene Chloride-
d2): δ = 7.98 (t, J = 8.1 Hz, 4H), 7.47 (dt, J = 10.0, 7.6 Hz, 4H), 7.34 (q, J = 7.2 Hz, 4H), 7.29
(d, J = 7.6 Hz, 4H), 7.20 (t, J = 8.7 Hz, 4H), 7.05 – 6.95 (m, 9H), 6.87 (d, J = 8.7 Hz, 2H), 6.82
– 6.80 (m, 2H), 6.55 (s, 1H), 6.44 (d, J = 8.5 Hz, 1H), 6.41 – 6.39 (m, 2H) ppm. 13C NMR (151
MHz, Methylene Chloride-d2): δ = 157.14 (d, J = 6.9 Hz), 147.48, 147.08, 140.56 (d, J = 2.8
Hz), 138.93, 136.93, 136.62, 136.46, 135.19, 133.92, 129.13, 128.68 (d, J = 5.8 Hz), 128.49 (d,
8
This article is protected by copyright. All rights reserved.

10.1002/chem.201806207
Chemistry - A European Journal
J = 2.0 Hz), 127.66 (d, J = 4.6 Hz), 127.23, 126.75 (d, J = 2.8 Hz), 126.39, 125.32, 125.13,
124.28, 123.44, 122.88, 120.32 (d, J = 7.5 Hz), 58.01, 57.76 ppm. MALDI-TOF-MS: m/z: calcd
for C56H37N: 723.919, found: 723.878. Anal. Calcd for C56H37N (%): C 92.91, H 5.15, N 1.93;
found: C 93.06, H 5.23, N 2.04.
Compound 3 was prepared with similar method as that for 2. 1H NMR (600 MHz, Methylene
Chloride-d2): δ = 7.82 (s, 1H), 7.79 (t, J = 7.6 Hz, 2H), 7.72 (t, J = 7.6 Hz, 2H), 7.64 (dd, J =
16.5, 7.8 Hz, 2H), 7.59 (d, J = 7.7 Hz, 2H), 7.56 (d, J = 7.4 Hz, 3H), 7.51 (t, J = 9.0 Hz, 2H),
7.32 (d, J = 8.4 Hz, 1H), 7.29 – 7.23 (m, 6H), 7.15 – 7.08 (m, 6H), 7.06 – 7.03 (m, 4H), 7.00 –
13
6.90 (m, 8H), 6.75 (q, J = 6.9 Hz, 4H), 6.44 (d, J = 8.3 Hz, 4H) ppm. C NMR (151 MHz,
Methylene Chloride-d2): δ = 147.60, 147.25, 143.86 (d, J = 9.1 Hz), 142.18, 141.16, 140.94,
140.82, 140.18, 140.05, 139.13, 134.46, 131.72, 131.61, 131.50, 131.45, 131.38, 131.15 (d, J
= 9.3 Hz), 131.01, 130.33, 129.17, 128.55 (d, J = 6.8 Hz), 128.23, 127.56, 127.11, 126.92,
126.68, 125.36, 124.31, 123.66, 122.90, 120.56 (d, J = 6.8 Hz), 114.73, 49.03, 48.64 ppm.
MALDI-TOF-MS: m/z: calcd for C68H47N3: 906.145, found: 906.124. Anal. Calcd for
C68H47N3 (%): C 90.13, H 5.23, N 4.64; found: C 90.19, H 5.28, N 4.52.
Experimental
Measurements and Characterization
All chemicals and reagents were used as received from commercial sources without further
purification. THF was purified by PURE SOLV (Innovative Technology) purification system.
13
1H NMR and C NMR spectra were recorded in chloroform-d (CDCl3) on a Bruker 400 and
Agilent DD2-600 MHz NMR spectrometer at room temperature. Matrix-Assisted Laser
Desorption/ Ionization Time of Flight Mass Spectrometry (MALDI-TOF-MS) was measured
with a BRUKER ultrafleXtreme MALDI-TOF/TOF. UV-vis absorption spectra were recorded
on Cary 60 spectrometer (Agilent Technologies). PL spectra and phosphorescent spectra were
recorded on a Hitachi F-4600 fluorescence spectrophotometer. Differential scanning
calorimetry (DSC) was performed on a TA DSC 2010 unit at a heating rate of 10 oC min-1 under
nitrogen. The glass transition temperatures (Tg) were determined from the second heating scan.
Thermogravimetric analysis (TGA) was performed on a TA SDT 2960 instrument at a heating
o
rate of 10 C min-1 under nitrogen. Temperature at 5% weight loss was used as the
decomposition temperature (Td). Cyclic voltammetry (CV) was carried out on a CHI600
voltammetric analyzer at room temperature with ferrocenium-ferrocene (Fc+/Fc) as the internal
standard. The oxidative scans were performed using 0.1 M n-Bu4NPF6 (TBAPF6) in deaerated
9
This article is protected by copyright. All rights reserved.

10.1002/chem.201806207
Chemistry - A European Journal
DMF as the supporting electrolyte. A conventional three-electrode configuration consisting of
a Pt-wire counter electrode, an Ag/AgCl reference electrode, and a platinum working electrode
was used. The cyclic voltammograms were measureed at a scan rate of 100 mV s-1. DFT
calculations were performed using B3LYP/6-31 G(d) basis set using Gaussian 09.
Device fabrication and characterization
The OLEDs were fabricated on the indium-tin oxide (ITO) coated transparent glass substrates,
the ITO conductive layer having a thickness of ca. 100 nm and a sheet resistance of ca. 30 Ω
per-square. The active area of each device is 0.09 cm2. The ITO glasses were ultrasonically
cleaned by ethanol, acetone and deionized water for 10 min subsequently, and then exposed to
UV-ozone for 15 min. All of the organic materials and metal layers under a vacuum of ca. 10-6
Torr. The deposition rate was controlled at 2 Å s-1 for HAT-CN, 0.2-0.4 Å s-1 for Liq, 1-2 Å s-
1 for other organic layers and 5-8 Å s-1 for Al anode. The EL spectra, CIE coordinates, J-V-L
curves, CE, and PE of the devices were measured with a programmable spectra scan photometer
(PHOTO RESEARCH, PR 655) and a constant current source meter (KEITHLEY 2400) at
room temperature.
Supporting Information
Supporting Information is available from the Wiley Online Library or from the author.
Acknowledgements
We acknowledge financial support from the National Key R&D Program of China
(2016YFB0400703), the National Natural Science Foundation of China (21472135, 61307036),
Natural Science Foundation of Jiangsu Province of China (BK20151216), and the 111 Project.
This project is also funded by Collaborative Innovation Center of Suzhou Nano Science and
Technology (CIC-Nano), Joint International Research Laboratory of Carbon-Based Functional
Materials and Devices,Soochow University and by the Priority Academic Program
Development of Jiangsu Higher Education Institutions (PAPD).
Received:
Revised:
((will
((will
be
be
filled
filled
in
in
by
by
the
the
editorial
editorial
staff))
staff))
Published online: ((will be filled in by the editorial staff))
[1] R. G. Clarkson, M. Gomberg, J. Am. Chem. Soc. 1930, 52, 2881.
10
This article is protected by copyright. All rights reserved.

10.1002/chem.201806207
Chemistry - A European Journal
[2] (a) C. Poriel, Y. Ferrand, P. le Maux, C. Paul, J. Rault-Berthelot, G. Simonneaux, Chem.
Commun. 2003, 18, 2308; (b) C. Poriel, A. Martail, G. Simonneaux, Inorg. Chem. Commun.
2007, 10, 627.
[3] (a) D. K. Smith, A. Zingg, F. Diederich, Helv. Chim. Acta 1999, 82, 1225; (b) G. Das, A.
D. Hamilton, Tetrahedron Lett. 1997, 38, 3675; (c) A. Tejeda, A. I. Oliva, L. Simon, M.
Grande, M. C. Caballero, J. R. Moran, Tetrahedron Lett. 2000, 41, 4563.
[4] (a) J. H. Fournier, T. Maris, J. D. Wuest, J. Org. Chem. 2004, 69, 1762; (b) E. Demers, T.
Maris, J. D. Wuest, Cryst. Growth Des. 2005, 5, 1227; (c) K. T. Wong, Y. L. Liao, Y. C.
Peng, C. C. Wang, S. Y. Lin, C. H. Yang, S. M. Tseng, G. H. Lee, S. M. Peng, Cryst. Growth
Des. 2005, 5, 667; (d) F. Moreau, N. Audebrand, C. Poriel, V. Moizan-Baslé, J. Ouvry, J.
Mater. Chem. 2011, 21, 18715.
[5] (a) J. Weber, A. Thomas, J. Am. Chem. Soc. 2008, 130, 6334; (b) J. Schmidt, M. Werner,
A. Thomas, Macromolecules 2009, 42, 4426; (c) S. Thomas, I. Pinnau, N. Y. Du, M. D.
Guiver, J. Membr. Sci. 2009, 333, 125.
[6] C. L. Chiang, S. M. Tseng, C. T. Chen, C. P. Hsu, C. F. Shu, Adv. Funct. Mater. 2008, 18,
248.
[7] A. Aviram, J. Am. Chem. Soc. 1988, 110, 5687.
[8] (a) J. M. Tour, R. Wu, J. S. Schumm, J. Am. Chem. Soc. 1990, 112, 5662; (b) J. M. Tour,
R. Wu, J. S. Schumm, J. Am. Chem. Soc. 1991, 113, 7064.
[9] J. Salbeck, N. Yu, J. Bauer, F. Weissörtel, H. Bestgen, Synth. Met. 1997, 91, 209.
[10] U. Bach, D. Lupo, P. Comte, J. E. Moser, F. Weissortel, J. Salbeck, H. Spreitzer, M.
Gratzel, Nature 1998, 395, 583.
[11] D. Shi, X. Qin, Y. Li, Y. He, C. Zhong, J. Pan, H. Dong, W Xu, T. Li, W. Hu, J.-L.
Brédas, O. M. Bakr, Sci. Adv. 2016, 2, e1501491.
[12] W. L. Yu, J. Pei, W. Huang, A. J. Heeger, Adv. Mater. 2000, 12, 828.
[13] (a) J. Pei, J. Ni, X.-H. Zhou, X.-Y. Cao, Y.-H. Lai, J. Org. Chem. 2002, 67, 4924; (b) X.
Zhang, J.-B. Han, P. F. Li, X. Ji, Z. Zhang, Synth. Commun. 2009, 39, 3804.
[14] (a) L.-S. Cui, S.-C. Dong, Y. Liu, M.-F. Xu, Q. Li, Z.-Q. Jiang, L.-S. Liao, Org.
Electron. 2013, 14, 1924; (b) L.-S. Cui, Y.-M. Xie, Y.-K. Wang, C. Zhong, Y.-L. Deng, X.-Y.
Liu, Z.-Q. Jiang, L.-S. Liao, Adv. Mater. 2015, 27, 4213; (c) L.-S. Cui, S.-B. Ruan, F.
Bencheikh, R. Nagata, L. Zhang, K. Inada, H. Nakanotani, L.-S. Liao, C. Adachi, Nat.
Commun. 2017, 8, 2250.
[15] (a) C. Poriel, J. Rault-Berthelot, J. Mater. Chem. C 2017, 5, 3869; (b) Z. Jiang, H. Yao,
Z. Zhang, C. Yang, Z. Liu, Y. Tao, J. Qin, D. Ma, Org. Lett. 2009, 11, 2607.
11
This article is protected by copyright. All rights reserved.

10.1002/chem.201806207
Chemistry - A European Journal
[16] L. Sicard, C. Quinton, J.-D. Peltier, D. Tondelier, B. Geffroy, U. Biapo, R. Métivier, O.
Jeannin, J. Rault-Berthelot, C. Poriel, Chem. Eur. J. 2017, 23, 7719.
[17] (a) W.-F. Jiang, H.-L. Wang, A.-G. Wang, Z. Q. Li, Synth. Commun. 2008, 38, 1888; (b)
W. Y. Huang, S. Y. Huang, Macromolecules 2010, 43, 10355; (c) K. Esashika, M.
Yoshizawa-Fujita, Y. Takeoka, M. Rikukawa, Synth. Met. 2009, 159, 2184.
[18] (a) L. Wang, B. Pan, L. Zhu, B. Wang, Y. Wang, Y. Liu, J. Jin, J. Chen, D. Ma, Dyes
Pigments 2015, 114, 222; (b) Y. Mo, X. Jiang, D. Cao, Org Lett. 2007, 9, 4371; (c) X. Zhang,
C. Jiang, Y. Mo, Y. Xu, H. Shi, Y. Cao, Appl. Phys. Lett. 2006, 88, 051116; (d) Y. Mo, L. Du,
L. Liu, J. Huang, Y. Pan, B. Yang, Z. Xie, Y. Ma, J. Phys. Chem. C 2013, 117, 27081.
[19] (a) V. Prelog, Pure Appl. Chem. 1978, 50, 893; (b) V. Prelog, D. Bedeković, Helv. Chim.
Acta 1979, 62, 2285; (c) F. Thiemann, T. Piehler, D. Haase, W. Saak, A. Lutzen, Eur. J. Org.
Chem. 2005, 1991; (d) X. Cheng, G. H. Hou, J. H. Xie, Q. L. Zhou, Org. Lett. 2004, 6, 2381;
(e) X. Cheng, S. F. Zhu, X. C. Qiao, P. C. Yan, Q. L. Zhou, Tetrahedron 2006, 62, 8077.
[20] (a) D. Curiel, M. Más-Montoya, G. Sánchez, Coord. Chem. Rev. 2015, 284, 19; (b) R.
Hovorka, S. Hytteballe, T. Piehler, G. Meyer-Eppler, F. Topić, K. Rissanen, M. Engeser, A.
Lützen, Beilstein J. Org. Chem. 2014, 10, 432; (c) R. Hovorka, G. Meyer-Eppler, T. Piehler,
S. Hytteballe, M. Engeser, F. Topić, K. Rissanen, A. Lützen, Chem. Eur. J. 2014, 20, 13253;
(d) J. Dong, Y. Liu, Y. Cui, Chem. Commun. 2014, 50, 14949; (e) Q. Fang, S. Gu, J. Zheng,
Z. Zhuang, S. Qiu, Y. Yan, Angew. Chem. Int. Ed. 2014, 53, 2878; (f) W. Yao, Q. Liu, Y. Shi,
J. Tang, Heterocycles 2012, 85, 1077.
[21] (a) Z. Wu, B. Han, C. Zhang, D. Zhu, L. Gao, M. Ding, Z. Yang, Polymer 2012, 53,
5706; (c) X. Cheng, Q. Zhang, J.-H. Xie, L.-X. Wang, Q.-L. Zhou, Angew. Chem. Int. Ed.
2005, 44, 1118; (d) C.-L. Chiang, C.-F. Shu, C.-T. Chen, Org. Lett. 2005, 17, 3717.
[22] (a) D. Hellwinkel, G. Haas, Liebigs Ann. Chem. 1978, 1978, 1913; (b) H. Oyama, M.
Akiyama, K. Nakano, M. Naito, K. Nobusawa, K. Nozaki, Org. Lett. 2016, 18, 3654; (c) Y.
Liu, Y. L. S. Tse, F. Y. Kwong, Y. Y. Yeung, ACS Catal. 2017, 7, 4453; (d) S. F. Gait, M. E.
Peek, C. W. Rees, R. C. Storr, J. Chem. Soc., Perkin Trans. 1974, 1, 1248.
[23] (a) E. H. Huntress, I. S. Cliff, J. Am. Chem. Soc. 1933, 55, 2559; (b) S. Kajigaeshi, K.
Kobayashi, S. Kurata, A. Kitajima, F. Nakahara, H. Nago, A. Nishiida, S. Fujisaki, Nippon
Kagaku Kaishi 1989, 12, 2052; (c) X.-Y. Chen, S. Ozturk, E. J. Sorensen, Org. Lett. 2017, 19,
1140.
[24] (a) L.-H. Xie, J. Liang, J. Song, C.-R. Yin, W. Huang, Curr. Org. Chem. 2010, 14, 2169;
(b) R. Pudzich, T. Fuhrmann-Lieker, J. Salbeck, Adv. Polym. Sci. 2006, 199, 83.
12
This article is protected by copyright. All rights reserved.

10.1002/chem.201806207
Chemistry - A European Journal
[25] (a) D. M. Bassani, L. Jonusauskaite, A. Lavie-Cambot, N. D. McClenaghan, J.-L. Pozzo,
D. Ray, G. Vives, Coord. Chem. Rev. 2010, 254, 2429; (b) H. Haick, D. Cahen, Prog. Surf.
Sci. 2008, 83, 217; (c) M. Valášek, K. Edelmann, L. Gerhard, O. Fuhr, M. Lukas, M. Mayor,
J. Org. Chem. 2014, 79, 7342; (d) N. J. Jeon, H. G. Lee, Y. C. Kim, J. Seo, J. H. Noh, J. Lee,
S. I. Seok, J. Am. Chem. Soc. 2014, 136, 7837; (e) K.-T. Wong, Y.-L. Liao, Y.-T. Lin, H.-C.
Su, C.-C. Wu, Org. Lett. 2005, 23, 5131; (f) M.-Y. Lai, C.-H. Chen, W.-S. Huang, J. T. Lin,
T.-H. Ke, L.-Y. Chen, M.-H. Tsai, C.-C. Wu, Angew. Chem. Int. Ed. 2008, 47, 581; (g) Y.
Lin, Z.-K. Chen, T.-L. Ye, Y.-F. Dai, D.-G. Ma, Z. Ma, Q.-D. Liu, Y. Chen, Polymer 2010,
51, 1270; (h) G. Liaptsis, D. Hertel, K. Meerholz, Angew. Chem. Int. Ed. 2013, 52, 9563.
[26] (a) R. Wu, J. S. Schumm, D. L. Pearson, J. M. Tour, J. Org. Chem. 1996, 61, 6906; (b)
Y. Lin, Z.-K. Chen, T.-L. Ye, Y.-F. Dai, D.-G. Ma, Z. Ma, Q.-D. Liu, Y. Chen, J. Polym. Sci.
A Polym. Chem. 2010, 48, 292; (c) R. Seto, T. Sato, T. Kojima, K. Hosokawa, Y. Koyama,
G.-I. Konishi, T. Takata, J. Polym. Sci. A Polym. Chem. 2010, 48, 3658.
[27] (a) S. Tang, M. Liu, C. Gu, Y. Zhao, P. Lu, D. Lu, L. Liu, F. Shen, B. Yang, Y. Ma, J.
Org. Chem. 2008, 73, 4212; (b) Y. Wu, J. Zhang, Z. Bo, Org. Lett. 2007, 9, 4435.
[28] L. Pop, F. Dumitru, N. D. Hꢀdade, Y.-M. Legrand, A. van der Lee, M. Barboiu, I. Grosu,
Org. Lett. 2015, 17, 3494.
[29] (a) T. P. I. Saragi, T. Spehr, A. Siebert, T. Fuhrmann-Lieker, J. Salbeck, Chem. Rev.
2007, 107, 1011; (b) R. Pudzich, T. Fuhrmann-Lieker, J. Salbeck, Adv. Polym. Sci. 2006, 199,
83.
[30] (a) W.-C. Chen, Y. Yuan, Z.-L. Zhu, S.-F. Ni, Z.-Q. Jiang, L.-S. Liao, F.-L. Wong, C.-S.
Lee, Chem. Commun. 2018, 54, 4541; (b) M.-M. Xue, C.-C. Huang, Y. Yuan, L.-S. Cui, Y.-
X. Li, B. Wang, Z.-Q. Jiang, M.-K. Fung, L.-S. Liao, ACS Appl. Mater. Interfaces 2016, 8,
20230.
[31] (a) C.-J. Lin, H.-L. Huang, M.-R. Tseng, C.-H. Cheng, J. Disp. Technol. 2009, 5, 236;
(b) K. Nasu, T. Nakagawa, H. Nomura, C.-J. Lin, C.-H. Cheng, M.-R. Tseng, T. Yasuda, C.
Adachi, Chem. Commun. 2013, 49, 10385.
[32] (a) M. Romain, D. Tondelier, B. Geffroy, A. Shirinskaya, O. Jeannin, J. Rault-Berthelot,
C. Poriel, Chem. Commun. 2015, 51, 1313; (b) M. Romain, D. Tondelier, O. Jeannin, B.
Geffroy, J. Rault-Berthelot, C. Poriel, J. Mater. Chem. C 2015, 3, 9701; (c) W. Zhang, J. Jin,
Z. Huang, S. Zhuang, L. Wang, Sci. Rep. 2016, 6, 30178.
[33] (a) M. Liu, R. Komatsu, X. Cai, K. Hotta, S. Sato, K. Liu, D. Chen, Y. Kato, H. Sasabe ,
S. Ohisa, Y. Suzuri, D. Yokoyama, S.-J. Su, J. Kido, Chem. Mater. 2017, 29, 8630; (b) N. A.
13
This article is protected by copyright. All rights reserved.

10.1002/chem.201806207
Chemistry - A European Journal
Drigo, L. G. Kudriashova, S. Weissenseel, A. Sperlich, A. J. Huckaba, M. K. Nazeeruddin, V.
Dyakonov, J. Phys. Chem. C 2018, 122, 22796.
[34] X.-Y. Liu, X. Tang, Y. Zhao, D. Zhao, J. Fan, L.-S. Liao, J. Mater. Chem. C 2018, 6,
1023.
[35] G. Tian, W. Liang, Y. Chen, N. Xiang, Q. Dong, J. Huang, J.-H. Su, Dyes Pigments
2016, 126, 296.
[36] (a) C. Poriel, J.-J. Liang, J. Rault-Berthelot, F. Barrière, N. Cocherel, A. M. Z. Slawin, D.
Horhant, M. Virboul, G. Alcaraz, N. Audebrand, L. Vignau, N. Huby, G. Wantz, L. Hirsch,
Chem. Eur. J. 2007, 13, 10055; (b) M. Romain, D. Tondelier, J.-C. Vanel, B. Geffroy, O.
Jeannin, J. Rault-Berthelot, R. Métivier, C. Poriel, Angew. Chem. Int. Ed. 2013, 52, 14147; (c)
M. Romain, S. Thiery, A. Shirinskaya, C. Declairieux, D. Tondelier, B. Geffroy, O. Jeannin,
J. Rault-Berthelot, R. Métivier, C. Poriel, Angew. Chem. Int. Ed. 2015, 54, 1176; (d) D.
Thirion, M. Romain, J. Rault-Berthelot, C. Poriel, J. Mater. Chem. 2012, 22, 7149; (e) M.
Romain, D. Tondelier, B. Geffroy, O. Jeannin, E. Jacques, J. Rault-Berthelot, C. Poriel,
Chem. Eur. J. 2015, 21, 9426; (f) C. Poriel, J. Rault-Berthelot, Acc. Chem. Res. 2018, 51,
1818.
[37] Y.-J. Cho, O.-Y. Kim, J.-Y. Lee, Org. Electron. 2012, 13, 351.
[38] (a) B. Li, Y. Qiu, L. Wang, Y. Gao, Jpn. J. Appl. Phys. 2002, 41, 5599; (b) K. H. Lee, S.
O. Kim, K. S. Yook, S. O. Jeon, J. Y. Lee, S. S. Yoon, Synth. Met. 2011, 161, 2024; (c) K. H.
Lee, S. O. Kim, J. N. You, S. Kang, J. Y. Lee, K. S. Yook, S. O. Jeon, J. Y. Lee, S. S. Yoon,
J. Mater. Chem. 2012, 22, 5145.
[39] X.-Y. Liu, X. Tang, Y. Zhao, D. Zhao, J. Fan, L.-S. Liao, ACS Appl. Mater. Interfaces
2018, 10, 1925.
[40] (a) B. Li, Y. Qiu, F. Wang, CN 1338499, 2002; (b) J. S. Ha, S. G. Hong, W. P. Hong,
KR 2017041648 A, 2017.
[41] K.-K. Kim, S. Son, S. Yoon, J.-S. Bae, Y.-G. Lee, S.-G. Im, J. Kim, J.-C. Lee, US Pat.
6,984,462, 2006.
[42] (a) Z. Chen, Z. Wu, F. Ni, C. Zhong, W. Zeng, D. Wei, K. An, D. Ma, C. Yang, J. Mater.
Chem. C 2018, 6, 6543; (b) C. Li, X. Fan, C. Han, H. Xu, J. Mater. Chem. C 2018, 6, 6747.
[43] (a) Y. Tao, Q. Wang, C. Yang, C. Zhong, J. Qin, D. Ma, Adv. Funct. Mater. 2010, 20,
2923; (b) M. G. Helander, Z. B. Wang, J. Qiu, M. T. Greiner, D. P. Puzzo, Z. W. Liu, Z. H.
Lu, Science 2011, 332, 944; (c) J. Liang, C. Li, X. Zhuang, K. Ye, Y. Liu, Y. Wang, Adv.
Funct. Mater. 2018, 28, 1707002.
[44] J. Zhao, G.-H. Xie, C.-R. Yin, L.-H. Xie, C.-M. Han, R.-F. Chen, H. Xu, M.-D. Yi, Z.-P.
14
This article is protected by copyright. All rights reserved.

10.1002/chem.201806207
Chemistry - A European Journal
Deng, S.-F. Chen, Y. Zhao, S.-Y. Liu, W. Huang, Chem. Mater. 2011, 23, 5331.
[45] G. Liaptsis, K. Meerholz, Adv. Funct. Mater. 2013, 23, 359.
15
This article is protected by copyright. All rights reserved.

10.1002/chem.201806207
Chemistry - A European Journal
5ʹ
4ʹ
6ʹ
7ʹ
3ʹ
2ʹ
8ʹ
1ʹ
8
1
7
2
6
3
5
4
Figure 1. General formula for mono-, di-, and tetra-substituted SBF derivatives.
Figure 2. Molecule structures of SBF analogues.
16
This article is protected by copyright. All rights reserved.

10.1002/chem.201806207
Chemistry - A European Journal
Figure 3. Representative dispiro-type OLED materials.
Scheme 1 Molecular structure and synthetic routes of 1, 2, 3, and 4.
17
This article is protected by copyright. All rights reserved.

10.1002/chem.201806207
Chemistry - A European Journal
351 oC
333 oC
134 oC
132 oC
230 oC
1
3
2
4
392 oC
80
120 160 200 240 280 320 360
Temperature (oC)
Figure 4. DSC curves of 1, 2, 3, and 4.
100
80
60
40
20
0
1 334 oC
2 438 oC
3 490 oC
4 396 oC
100
200
300
400
500
600
700
Temperature (oC)
Figure 5. TGA curves of 1, 2, 3, and 4.
18
This article is protected by copyright. All rights reserved.

10.1002/chem.201806207
Chemistry - A European Journal
1.0
0.5
0.0
UV-Vis
PL
Phos
1
1
1
2
2
2
3
3
3
4
4
4
300
350
400
450
1.0
0.5
0.0
300
350
400
500
450
500
1.0
0.5
0.0
400
450
550
600
Wavelength (nm)
Figure 6. UV-Vis absorption, PL, and Phos spectra of 1, 2, 3, and 4 in toluene solution.
19
This article is protected by copyright. All rights reserved.

10.1002/chem.201806207
Chemistry - A European Journal
Hole
S1
1
Particle
Hole
T1
1
Particle
99.99%
98.40%
89.41%
94.90%
4
4
Hole
Particle
S1
2
Hole
T1
2
Particle
99.83%
99.77%
96.43%
96.65%
3
3
Figure 7. The natural transition orbital (NTO) analysis of 1, 2, 3, and 4.
20
This article is protected by copyright. All rights reserved.

10.1002/chem.201806207
Chemistry - A European Journal
1
2
0.0
0.5
1.0
1.5
0.0
0.5
1.0
1.5
3
4
0.0
0.5
1.0
1.5
2.0
0.0
0.5
1.0
1.5
Voltage (V)
Figure 8. Cyclic voltammograms of 1, 2, 3, and 4.
21
This article is protected by copyright. All rights reserved.

10.1002/chem.201806207
Chemistry - A European Journal
1
2
3
4
-0.53 eV
-4.92 eV
LUMO
-0.78 eV
-0.83 eV
-0.84 eV
-4.86 eV
-4.90 eV
-5.67 eV
HOMO
Figure 9. HOMO/LUMO distributions and energy levels and optimized geometry of 1, 2, 3,
and 4.
22
This article is protected by copyright. All rights reserved.

10.1002/chem.201806207
Chemistry - A European Journal
Table 1. Physical properties of 1, 2, 3, and 4.
a)
a)
b)
e)
f)
g)
Abs λmax
PL λmax
Tg /Tcc)/Tmd)/Td
Eg
ET
HOMOh) LUMOi)
Host
[nm]
[nm]
[oC]
[eV] [eV]
3.92 2.86
[eV]
[eV]
300, 311
300, 311,
337
316, 327
385
-/-/351/334
-5.82
-1.90
1
2
-/-/333/438
3.35 2.57
-5.23
-1.88
323
385
348
132/230/-/490 3.35 2.58
134/-/392/396 3.63 3.04
-5.24
-5.34
-1.89
-1.71
3
4
310
a) Measured in toluene solution at room temperature.
b) Tg: Glass transition temperature.
c) Tc: Crystallization temperature.
d) Tm: Melting point.
e) Td: Decomposition temperature.
f) Eg: Band gap energies were calculated from the corresponding absorption onsets.
g) ET: Measured in toluene glass matrix at 77 K.
h) HOMO levels were calculated from CV data.
i) LUMO levels were calculated from the HOMOs and Egs.
23
This article is protected by copyright. All rights reserved.

10.1002/chem.201806207
Chemistry - A European Journal
(a)
60
50
40
30
20
10
0
10k
1k
100
10
1
2
3
4
1
2
3
4
5
6
7
Voltage (V)
80
(b)
60
40
20
0
100
75
50
25
0
1
3
2
4
24
18
12
6
0
0
5000
10000
15000
20000
-2
Luminance (cd m )
(c)
1.0
0.8
0.6
0.4
0.2
0.0
1
2
3
4
-2
@ 5 mA cm
300
400
500
600
700
800
Wavelength (nm)
Figure 10. (a) J–V–L characteristics, (b) CE–, PE–, and EQE–L curves, and (c) EL spectra of
green devices.
24
This article is protected by copyright. All rights reserved.

10.1002/chem.201806207
Chemistry - A European Journal
90
60
30
0
1
2
3
4
Hole-only devices
0.9
0.6
0.3
0.0
Electron-only devices
0
2
4
6
8
10
12
14
16
18
20
Voltage (V)
Figure 11. J–V characteristics curves of single carrier devices.
25
This article is protected by copyright. All rights reserved.

10.1002/chem.201806207
Chemistry - A European Journal
Table 2. Electroluminescence characteristics of the green and red devices.
Vb
CE
PE
EQEc
CIEd
c
c
Devicea
Hosta
[V]
3.24
2.47
2.53
2.65
[cd A-1]
57.0, 46.2
78.0, 77.1
76.0, 75.5
65.0, 61.9
[lm W-1]
59.5, 39.4
100.5, 93.4
96.1, 89.5
80.0, 69.2
[%]
[x, y]
G1
G2
G3
G4
16.0, 13.2
21.7, 21.3
21.3, 21.0
18.3, 17.4
0.33, 0.63
0.34, 0.62
0.33, 0.63
0.33, 0.63
1
2
3
4
a) The notation 1-4 in devices G1-G4 indicates the corresponding devices fabricated with 1,
2, 3, and 4 as the host respectively. Device configuration: G1-G4: ITO/ HAT-CN (10 nm)/
TAPC (55 nm)/ Host: 10 wt% Ir(ppy)2(acac) (20 nm)/ B4PyMPM (40 nm)/ Liq (2 nm)/ Al
(120 nm).
b) Voltages at 200 cd m-2.
c) Efficiencies in the order of the maxima and at 500 cd m-2.
d) Commission International de I’Eʹclairage coordinates measured at 5 mA cm-2.
26
This article is protected by copyright. All rights reserved.

10.1002/chem.201806207
Chemistry - A European Journal
The table of contents entry: Dispirocycles molecular platforms as rigid building blocks to
construct efficient host materials for phosphorescent organic light-emitting diodes
Keyword: Dispirocycles, Host materials, Phosphorescence, OLEDs, Triplet energy
Xiang-Yang Liu,† Yi-Jie Zhang,† Xiyu Fei, Man-Keung Fung,* and Jian Fan*
Dispirocycles: Novel Platforms for Construction of High-Performance Host Materials for
Phosphorescent Organic Light-Emitting Diodes
Dispirocycles: Novel
Platforms for Host
Materials
+
+
Over 21% EQE, 100 lm W-1 PE
27
This article is protected by copyright. All rights reserved.