Electron-withdrawing groups and strong-field ligands containing iridium(III) complexes and their efficient blue light-emitting

Article abstract of DOI:10.1016/j.inoche.2010.06.031

Two new heteroleptic iridium(III) complexes [Ir(4,6-dfppy) ₂(PPh₃)L] (4,6-dfppy = 2-(4,6-difluorophenyl)pyridyl, PPh₃ = triphenylphosphine, L = NCS^-, 1; NCO^-, 2) have been synthesized and fully charac

Full text of DOI:10.1016/j.inoche.2010.06.031

Inorganic Chemistry Communications 13 (2010) 1096–1099
Contents lists available at ScienceDirect
Inorganic Chemistry Communications
journal homepage: www.elsevier.com/locate/inoche
Electron-withdrawing groups and strong-field ligands containing iridium(III)
complexes and their efficient blue light-emitting
⁎
⁎
Xuan Shen , Xiu-Hua Hu, Feng-Ling Wang, Feng Sun, Yu-Qi Yang, Yan Xu, Su Chen, Dun-Ru Zhu
State Key Laboratory of Materials-oriented Chemical Engineering, College of Chemistry and Chemical Engineering, Nanjing University of Technology, Nanjing 210009, PR China
a r t i c l e i n f o
a b s t r a c t
Article history:
Two new heteroleptic iridium(III) complexes [Ir(4,6-dfppy)2(PPh3)L] (4,6-dfppy=2-(4,6-difluorophenyl)
pyridyl, PPh3 =triphenylphosphine, L=NCS−, 1; NCO−, 2) have been synthesized and fully characterized. By
introduction of electron-withdrawing groups such as fluorine atoms on the 4- and 6-positions of 2-
phenylpyridyl (ppy) and using strong-field ligands for instance PPh3 and pseudohalogen as ancillary ligands,
the HOMO–LUMO electronic energy gaps of 1 and 2 have been increased sufficiently. The photoluminescence
(PL) spectra of 1 and 2 in solution show emission maxima at 456 and 458 nm, respectively, corresponding to
efficient blue light-emitting. X-ray analyses show that intra- and intermolecular π–π interactions exist in the
solid state of 1 and 2. The PL spectra of 1 and 2 in solid state exhibit about 30 nm spectral red shifts compared
with those in solution.
Received 11 May 2010
Accepted 13 June 2010
Available online 20 June 2010
Keywords:
Heteroleptic iridium(III) complexes
Electron-withdrawing group
Strong-field ligand
HOMO–LUMO energy gap
PL spectra
© 2010 Elsevier B.V. All rights reserved.
Blue light-emitting
In recent years, iridium(III) cyclometalated complexes have
received considerable attention because of their outstanding photo-
chemical and photophysical properties, which make this class of
complexes be widely applied to a variety of photonic applications and
emissive materials in organic light-emitting diodes (OLEDs) [1]. Many
luminescent Ir(III) complexes, mostly based on cyclometalating
ligands, for instance 2-phenylpyridyl (ppy), have been reported in
the last decade. Ir(III) complexes containing ppy are known to exhibit
high triplet quantum yields due to mixing the singlet and the triplet
excited states via spin–orbit coupling, which enhances the triplet-
state subsequently, leading to high phosphorescence efficiencies [2–
4]. Furthermore, emission wavelengths of ppy-based Ir(III) cyclome-
talated complexes can be tuned so as to cover a full range of visible
colors, from red [5–9] to orange [10,11], then to green [12–17] and
blue. In the development of phosphorescent Ir(III) complexes
showing all three primary colors for full-color displays, blue-emitting
complexes are more difficult to achieve than red- and green-emitting
ones [18].
In order to design efficient blue-emitting ppy-based Ir(III)
complexes, it is necessary to increase the HOMO–LUMO electronic
energy gap, leading to a blue shift in emission. There are two
strategies for achieving this purpose. The first is maintaining the
HOMO energy relatively unchanged and increasing the LUMO energy.
This can be realized by replacement of the heterocycylic fragment of
the (C^N) ligand with moieties bearing higher lying LUMO than for
the pyridyl ring of ppy. These can be either N-pyrazolyl, triazolyl, or N-
heterocyclic carbene-based moieties [19–22]. The second strategy
involves decreasing the HOMO energy while keeping the LUMO
energy relatively unchanged. To achieve this goal, a few attempts have
been made through the use of strong-field electron-withdrawing
ancillary ligands (LL) such as CO, cyanide and PPh3 to decrease the
HOMO energies of Ir(ppy)2(LL) complexes [23–27]. The addition of
electron-withdrawing groups, for instance fluoride, to the phenyl ring
of ppy has been used as another effective way to achieve the goal of
decreasing the HOMO energy and keeping the LUMO energy
unchanged [13,19–21,28]. In our previous work, a series of neutral
Ir(ppy)2(LL) complexes in which strong-field ligands PPh3 and
pseudohalogens are used as ancillary ligands have been synthesized.
The photoluminescence (PL) spectra of those complexes show
emission maxima in blue and blue–green light-emitting ranges
[29,30]. Herein, as extension of the research, we present two new Ir
(III) complexes [Ir(4,6-dfppy)2(PPh3)L] (4,6-dfppy=2-(2,4-difluor-
ophenyl)pyridyl, PPh3 =triphenylphosphine, L=NCS−, 1; NCO−, 2),
in which not only strong-field ancillary ligands have been used, but
also electron-withdrawing fluorine atoms have been introduced in
the phenyl ring of ppy to achieve blue-shifted emission by increasing
the HOMO–LUMO gap. As a consequence, 1 and 2 show efficient blue
emission.
The reaction of PPh3 and chloride-bridged dimer [Ir(4,6-dfppy)2-
Cl]2 which was synthesized according to the procedure described in
the literature [13] led to the intermediate product [Ir(4,6-dfppy)2
(PPh3)Cl] [31]. 1 and 2 can be synthesized using [Ir(4,6-dfppy)2(PPh3)
Cl] as starting reagent, by replacing the weak π donor Cl− with the
strong σ donor and π acceptor NCS− and NCO− [32,33]. The crystal
structures of 1 and 2 have been confirmed by X-ray analysis [34].
ORTEP views of 1 and 2 are shown in Fig. 1.
⁎
Corresponding authors. Tel.: +86 25 8358 7717; fax: +86 25 8336 5813.
E-mail addresses: shenxuan@njut.edu.cn (X. Shen), zhudr@njut.edu.cn (D.-R. Zhu).
1387-7003/$ – see front matter © 2010 Elsevier B.V. All rights reserved.
doi:10.1016/j.inoche.2010.06.031

X. Shen et al. / Inorganic Chemistry Communications 13 (2010) 1096–1099
1097
Fig. 1. ORTEP drawings of 1 (left) and 2 (right). The thermal ellipsoids are drawn at the 50% probability level. The H atoms and the solvent (CHCl3) of 2 are omitted for clarity. Selected
bond distances (Å) and angles (°) for 1: Ir1–N1 2.048(5), Ir1–N2 2.071(4), Ir1–N3 2.118(4), Ir1–P1 2.4490(15), Ir1–C11 2.009(5), Ir1–C22 2.032(5); N1–Ir1–N2 168.87(17), N3–Ir1–
C11 173.12(19), P1–Ir1–C22 171.90(14); for 2: Ir1–N1 2.052(9), Ir1–N2 2.044(9), Ir1–N3 2.425(5), Ir1–P1 2.1417(2), Ir1–C11 2.035(8), Ir1–C22 2.025(7); N1–Ir1–N2 168.8(3), N3–
Ir1–C11 173.6(3), P1–Ir1–C22 175.58(18).
Both complexes assume the analogous distorted octahedral
geometry about the metal center with mutually trans pyridyls and
cis phenyls and with the PPh3 and pseudohalogen ligands positioned
trans to the phenyl–Ir bonds. Hence, the 4,6-dfppys of the dimer
precursor [Ir(4,6-dfppy)2Cl]2 did not undergo isomerization in the
multistep synthesis. Taking one with another, corresponding metric
parameters between the two complexes are similar and the bond
distances for phenyl and pyridyl groups are relatively unperturbed by
the F substituents. However, the Ir–Cphenyl bond opposite to thiocya-
nide is 0.024 Å shorter than that opposite to PPh3 in 1, demonstrating
that thiocyanide exerts a weaker trans influence than PPh3. Whereas in
2, the Ir–Cphenyl bond opposite to cyanate is 0.010 Å longer than that
opposite to PPh3, showing that cyanate exerts a slightly stronger trans
influence than PPh3. Likewise, in 1 and 2, Ir–Npyridyl bonds in 4,6-
dfppys with longer Ir–Cphenyl bonds are also longer than those in 4,6-
dfppys with shorter Ir–Cphenyl bonds. Furthermore, Ir–Npseudohalogen
bond in 1 is 0.307 Å shorter than that in 2, corresponding to the fact
that thiocyanide is stronger ligand compared with cyanate. Not only C–
C and C–N intraligand bond lengths but also bond angles of the two
complexes are within normal ranges expected for cyclometalated Ir
(III) complexes. Corresponding bond angles of Npyridyl–Ir–Npyridyl in
the two complexes, as well as those of Npseudohalogen–Ir–Cphenyl, are
very similar, which are both around 173°. However, bond angle of P–
Ir–Cphenyl in 1 (171.89°) is markedly different from that in 2 (175.58°).
The two pseudohalogen ligands keep their linearities. The N–C–S bond
angle in 1 is 179.6° and the N–C–O bond angle in 2 is 176.6°.
Nevertheless, the Ir–N–C bond angle involving thiocyanide in 1 is
171.7°, which is surprisingly different from that involving cyanate in 2
(144.0°). This may be due to larger terminal atom of thiocyanide ligand
in 1 compared with that of cyanate ligand in 2. The repulsion between
the pseudohalogen ligand and PPh3 in 1 is larger than that in 2. Because
of intra- and intermolecular interactions, phenyl and pyridyl rings in
all 4,6-dfppys are not coplanar. The dihedral angles of phenyl and
pyridyl rings are 8.86° (F1,F2-dfppy) and 8.32° (F3,F4-dfppy) in 1,
7.04° (F1,F2-dfppy) and 10.37° (F3,F4-dfppy) in 2, respectively.
The UV–vis absorption and photoluminescence (PL) data of 1 and
2 are summarized in Table 1. Fig. 2 shows the UV–vis absorption and
PL spectra of 1 and 2 in CH2Cl2 solution at room temperature. The two
complexes exhibit very similar absorption spectra, suggesting that the
ancillary pseudohalogen ligand makes only a small contribution to the
absorption process in this system. Furthermore, the absorption
spectra of 1 and 2 are comparable with those of the related Ir(III)
cyclometalated complexes [36,37]. The high-energy bands at around
245 nm are assigned to the intraligand π–π* transition of 4,6-dfppy.
The strong spin-allowed ligand-centered absorptions (1LC) appear at
about 300 nm and spin-allowed metal-to-ligand charge transfer
(1MLCT) absorptions are clearly distinguished at about 370 nm. In
addition, spin-forbidden triplet 3LC and/or 3MLCT transitions appear
as low-energy absorption shoulders at approximately 450 nm.
Apparently, the absorption spectra of 1 and 2 overall blue shift
compared to those of previously reported ppy-based Ir(III) complexes
in which same ancillary PPh3 and pseudohalogen ligands have been
used [29] and even of other 4,6-dfppy-based Ir(III) complexes with
other ancillary ligands [26,38,39], indicating the higher HOMO–LUMO
electronic energy gaps in 1 and 2. Not surprisingly, compared with the
absorption spectra of 1 and 2, PL spectra of 1 and 2 also exhibit
analogous curves and emission peaks, showing the maximum
intensity at 456 and 458 nm, respectively, corresponding to efficient
blue light-emitting as shown in Fig. 2. The PL spectra of the previously
reported ppy-based Ir(III) complexes [Ir(ppy)2(PPh3)(NCS)] and [Ir
Table 1
Photophysical properties of 1 and 2 in dichloromethane solution at room temperature.
Complex
Abs. λmax (nm)
PL λmax (nm)a
Solutionb
PLQYs in
solutionc
(ε, 103 M−1 cm−1
)
Solid
483
1
2
448sh (0.01), 366 (3.46),
301 (13.28), 245 (43.06)
450sh (0.02), 371 (3.42),
303sh (12.2), 247sh (37.59)
456, 484
0.39
0.14
458, 488
486
a
Excitation wavelength for both solution and solid emission measurements was
320 nm.
b
c
First two highest intension peaks.
PLQYs in solution were measured by a relative method [35] using 0.2 μg/mL quinine
sulfate solution in 0.5 N sulfuric acid as a standard.

1098
X. Shen et al. / Inorganic Chemistry Communications 13 (2010) 1096–1099
solution and is typically ascribed to excimer formation [40]. Being
different from a series of heteroleptic Ir(III) complexes bearing two N-
phenyl-substituted pyrazoles and one 2-pyridyl pyrazole (or triazole)
ligands, which slight or negligible spectral blue shifts are observed in the
solid state PL spectra [22], the solid state PL spectra of 1 and 2 show the
maximum intensity at 484 and 488 nm, respectively, exhibiting about
30 nm spectral red shifts. Also being different from [Ir(ppy)2(acac)]
(acac=acetylacetonate) and [Ir(tpy)2(acac)] (tpy=2-(4-tolyl)pyridyl),
which exhibit pronounced differences in their solid state PL spectra [12],
1 and 2 show analogous solid state PL spectra.
In summary, by introduction of electron-withdrawing groups such
as fluorine atoms on the 4- and 6-positions of ppy and using strong-
field ligands for instance PPh3 and pseudohalogen as ancillary ligands,
two new heteroleptic iridium(III) complexes [Ir(4,6-dfppy)2(PPh3)L]
(L=NCS−, 1; NCO−, 2) with high HOMO–LUMO electronic energy
gaps have been designed and synthesized. The PL spectra of 1 and 2 in
solution show emission maxima at 456 and 458 nm with somewhat
high PLQYs of 0.39 and 0.14, respectively, corresponding to efficient
blue light-emitting. Because of intra- and intermolecular π–π inter-
actions existing in the single crystals of 1 and 2, the solid state PL
spectra of 1 and 2 show the maximum intensity at 484 and 488 nm,
respectively, exhibiting about 30 nm spectral red shifts compared
with those in solution. The results provide a cogent example for future
design and synthesis of the corresponding analogues suited to blue
phosphorescent emitters.
Fig. 2. UV–vis absorption spectra of 1 and 2 in dichloromethane (5.0×10−5 M) and PL
spectra of
temperature.
1 and 2 λex =320 nm) at room
in dichloromethane (1.0×10−4 M;
(ppy)2(PPh3)(NCO)] show emission maxima at 477 and 485 nm,
respectively, corresponding to blue–green light-emitting [29]. With-
out doubt, substitution of the phenyl hydrogens with electron-
withdrawing fluorinated atoms on the 4- and 6-positions decreases
the HOMO energy while keeping the LUMO energy relatively
unchanged, thus leading to the increase of the HOMO–LUMO energy
gap. Therefore, by replacing ppy with 4,6-dfppy as cyclometalating
ligand, hypsochromic shifted emissions are observed. The PL spectra
of some other typical 4,6-dfppy-based Ir(III) complexes with other
ancillary ligands also show the maximum intensity at the region of
blue wavelength [26,38,39]. However, compared with those Ir(III)
complexes, 1 and 2 show emission maxima at markedly shorter
wavelengths in the PL spectra. Though first two highest intension
peaks in the PL spectrum of [Ir(4,6-dfppy)2(t-BuNC)(CN)] (t-
BuNc=t-butyl isocyanide) have been reported at 442 and 472 nm,
respectively [26], the higher intension peak (472 nm) appears in long-
wavelength region. However, in the spectrum of 1 or 2, the higher
intension peak (456 nm of 1 or 458 nm of 2) appears in short-
wavelength region. Thus, it can be estimated that the solutions of 1
and 2 are supposed to emit better blue phosphorescence than that of
[Ir(4,6-dfppy)2(t-BuNC)(CN)]. Furthermore, compared with other
blue phosphorescent Ir(III) complexes [18–23], 1 and 2 also show
distinctive blue light-emitting properties, while maintaining some-
what high PL quantum yields (PLQYs) of 0.39 and 0.14, respectively.
The PL spectra of 1 and 2 in solid state have also been measured (Fig. 3
and Table 1). Generally speaking, π–π interactions between aromatic
molecules in the solid state often lead to a broad and featureless
luminescence that is red shifted from the emission that occurs in dilute
Acknowledgements
We are grateful to the Natural Science Foundation of the Jiangsu
Higher Education Institutions of China (09KJB150003) and the
National Natural Science Foundation of China (20771050,
20771059) for financial support.
Appendix A. Supplementary material
CCDC 740914 and 770645 contain the supplementary crystallo-
graphic data for compounds 1 and 2. These data can be obtained free
of charge from The Cambridge Crystallographic Data Centre via http://
www.ccdc.cam.ac.uk/data_request/cif.
Supplementary data associated with this article can be found, in
the online version, at doi:10.1016/j.inoche.2010.06.031.
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8.99 (d, J=5.2 Hz, 1H), 8.43 (d, J=6.3 Hz, 1H), 7.93 (d, J=8.3 Hz, 1H), 7.82 (t,
J=7.4 Hz, 1H), 7.48 (d, J=9.5 Hz, 1H), 7.39 (t, J=8.3 Hz, 1H), 7.32–7.23 (m, 8H),
7.16–7.12 (m, 7H), 7.00 (d, J=5.7 Hz, 1H), 6.95 (t, J=6.5 Hz, 1H), 6.45 (t,
J=10.6 Hz, 1H), 6.34 (d, J=8.7 Hz, 1H), 6.29 (t, J=8.6 Hz, 1H), 5.91 (t, J=8.7 Hz,
1H). 31P NMR (500 MHz, CDCl3) (ppm): δ −2.49.
[33] 2: By replacing ammonium thiocyanate with sodium cyanate, the reaction was
carried out in a similar method as described in [33]. Yellow block crystals of 2
containing one molecule of chloroform, which were suitable for X-ray crystal
structure analysis, were obtained in a yield of 61.2 mg (70%). Anal. Calc. for
2·CHCl3 (C42H28Cl3F4IrN3OP, 996.23): C, 50.64; H, 2.83; N, 4.22. Found: C, 50.77;
H, 2.88; N, 4.20%. IR (KBr pellet, cm−1): ν(C≡N) 2231; ν(C C, C N) 1602, 1573,
+
1432, 1403; ν(P–C) 1478; ν(F–C) 1102. ESI-MS: m/z=835 (M-NCO−
)
.
1H NMR
(500 MHz, CDCl3) (ppm): δ 9.32 (d, J=6.1 Hz, 1H), 8.88 (d, J=5.9 Hz, 1H), 8.35
(d, J=10.8 Hz, 1H), 8.00 (d, J=8.3 Hz, 1H), 7.77 (t, J=7.7 Hz, 1H), 7.54 (t,
J=7.5 Hz, 1H), 7.33–7.26 (m, 8H), 7.20–7.14 (m, 7H), 6.81 (t, J=7.4 Hz, 1H), 6.75
(t, J=7.3 Hz, 1H), 6.36 (m, 2H), 5.34 (d, J=5.5 Hz, 1H), 5.23 (t, J=9.8 Hz ,1H). 31
NMR (500 MHz, CDCl3) (ppm): δ −4.12.
P
[34] Suitable yellow block crystals of 1 and 2 were selected for X-ray analysis. All
diffraction data were collected on a Bruker Smart APEX II CCD diffractometer
equipped with a graphite-mono-chromatized Mo-Kα radiation (λ=0.71073 Å) at
296(2) K. Cell parameters were retrieved using SMART software and refined using
SAINTPLUS for all observed reflection. Data reduction and correction for decay
were performed using the SAINTPLUS software. Semi-empirical absorption
corrections were applied by SADABS. The structures of 1 and 2 were solved by
direct methods using SHELXS-97 program of the SHELXL package and refined
with SHELXL-97 program. All non-hydrogen atoms were refined anisotropic
thermal parameters. Hydrogen atoms were introduced in calculated positions and
included in the refinement, riding on their respective parent atoms. Crystallo-
graphic data for 1: C41H27F4IrN3PS, Mr =892.89, triclinic P1 with a=9.8875(10) Å,
[31] [Ir(4,6-dfppy)2(PPh3)Cl]: Triphenylphosphine (104 mg, 0.40 mmol) was added to
a solution of [Ir(4,6-dfppy)2Cl]2 (111 mg, 0.10 mmol) in chloroform (60 mL)
under nitrogen atmosphere. The reaction mixture was stirred for 48 h and then
filtered. The filtrate was then reelingly evaporated to remove the solvent and
crude product was obtained as a yellow powder. The product was purified by
passing through a column of silica using chloroform/methanol (160:1 v/v) as
eluent. Yellow microcrystals of [Ir(4,6-dfppy)2(PPh3)Cl] were obtained by
recrystallization from chloroform/methanol (2:1 v/v) in a yield of 88 mg (50%).
Anal. Calc. for [Ir(4,6-dfppy)2(PPh3)Cl] (C40H27ClF4IrN2P, 870.29): C, 55.20; H,
3.13; N, 3.22. Found: C, 55.34; H, 3.08; N, 3.26%. IR (KBr pellet, cm−1): ν(C C, C N)
+
1602, 1573, 1432, 1403; ν(P–C) 1478; ν(F–C) 1096. ESI-MS: m/z=835 (M-Cl−
)
.
1H NMR (500 MHz, CDCl3) (ppm): δ 9.26 (d, J=5.9 Hz, 1H), 8.88 (d, J=5.7 Hz,
1H), 8.34 (d, J=10.9 Hz, 1H), 8.00 (d, J=8.4 Hz, 1H), 7.77 (t, J=7.9 Hz, 1H), 7.54
(t, J=8.0 Hz, 1H), 7.32–7.25 (m, 8H) , 7.17–7.14 (m, 7H), 6.76 (t, J=4.8 Hz, 1H),
6.74 (t, J=4.3 Hz, 1H), 6.38–6.32 (m, 2H), 5.35 (d, J=10.8 Hz, 1H), 5.23 (t,
J=8.2 Hz ,1H).
b=12.7729(14) Å, c=15.1367(16) Å, α=88.1320(10)°, β=73.8190(10)°,
3
γ=72.3080(10)°, V=1746.2(3)
, , F(0 0 0)=876,
Z=2, Dc =1.698 gcm−3
GOF=1.082, R1 =0.0311, ωR2 =0.0878 for all data. 2·CHCl3: C41H27F4IrN3-
OP·CHCl3, Mr =996.19, monoclinic Cc with a=22.552(2) Å, b=10.9519(10) Å,
c=16.9695(15) Å, β=113.7950(10)°, V=3835.0(6) 3, Z=4, Dc =1.725 gcm−3
F(0 0 0)=1952, GOF=1.039, R1 =0.0655, ωR2 =0.1768 for all data.
[35] J.N. Demas, G.A. Crosby, J. Phys. Chem. 75 (1971) 991.
,
[32] 1: Ammonium thiocyanate (37 mg, 0.55 mmol) was added to a solution of [Ir(4,6-
dfppy)2(PPh3)Cl] (94 mg, 0.11 mmol) in 40 mL mixture of chloroform and
methanol (1:1 v/v). The reaction mixture was then refluxed with stirring for
24 h under nitrogen atmosphere. After being cooled to room temperature, the
solution was filtered and insoluble crude 1 was obtained as a yellow solid after
being washed with hexane. Yellow block crystals of 1, which were suitable for X-
ray crystal structure analysis, were obtained by recrystallization from chloroform/
methanol (3:1 v/v) in a yield of 79 mg (84%). Anal. Calc. for 1 (C41H27F4IrN3PS,
892.92): C, 55.15; H, 3.05; N, 4.71. Found: C, 55.09; H, 3.12; N, 4.63%. IR (KBr
[36] F.D. Angelis, S. Fantacci, N. Evans, C. Klein, S.M. Zakeeruddin, J.-E. Moser, K.
Kalyanasundaram, H.J. Bolink, M. Grätzel, M.K. Nazeeruddin, Inorg. Chem. 46
(2007) 5989.
[37] J.-Y. Hung, Y. Chi, I.-H. Pai, Y.-C. Yu, G.-H. Lee, P.-T. Chou, K.-T. Wong, C.-C. Chen,
C.-C. Wu, Dalton Trans. (2009) 6472.
[38] Y. You, S.Y. Park, J. Am. Chem. Soc. 127 (2005) 12438.
[39] Y. You, K.S. Kim, T.K. Ahn, D. Kim, S.Y. Park, J. Phys. Chem. C 111 (2007) 4052.
[40] J.B. Birks, Photophysics of Aromatic Molecules, Wiley-Interscience, New York,
1970.
pellet, cm−1): ν(C≡N) 2103; ν(C C, C N) 1604, 1576, 1433, 1403; ν(P–C) 1478;
+
ν(F–C) 1103. ESI-MS: m/z=835 (M-NCS−
)
.
1H NMR (500 MHz, CDCl3) (ppm): δ