Synthesis and characterization of gold(I) complexes with 9-(4-isocyanophenyl)carbazole or 9-ethyl-3-isocyanocarbazole ligands

Article abstract of DOI:10.1002/ejic.200900692

The carbazole derivatives 9-(4-isocyanophenyl)carbazole, 3, 6-dibromo-9-(4-isocyanophenyl) carbazole, and 9-ethyl-3-isocyanocarbazole were prepared, and used to synthesize [AuX(CN-carbazole)] (X = Cl, C ₆F₅, C₆F₄

Full text of DOI:10.1002/ejic.200900692

FULL PAPER
DOI: 10.1002/ejic.200900692
Synthesis and Characterization of Gold(I) Complexes with
9-(4-Isocyanophenyl)carbazole or 9-Ethyl-3-isocyanocarbazole Ligands
Rut Benavente,[a] Pablo Espinet,*[a] Sergio Lentijo,[a] Jose M. Martín-Álvarez,[a]
Jesús A. Miguel,*[a] and M. Paz Rodríguez-Medina[a]
Keywords: Gold / Nitrogen heterocycles / Isocyanide ligands / Luminescence
The carbazole derivatives 9-(4-isocyanophenyl)carbazole,
3,6-dibromo-9-(4-isocyanophenyl)carbazole, and 9-ethyl-3-
isocyanocarbazole were prepared and used to synthesize
[AuX(CN-carbazole)] (X = Cl, C6F5, C6F4-OEt-p) gold com-
determined. All the gold complexes show a redshift in the
emissions relative to that of the free ligand. The presence of
electron-withdrawing substituents in 3,6-dibromo-9-(4-iso-
cyanophenyl)carbazole quenches the luminescence, but with
plexes. The X-ray structures of [Au(C6F4-OEt-p){9-(4-isocy- the introduction of a gold atom some luminescence is reco-
anophenyl)carbazole}] and [Au(C6F5)(9-ethyl-3-isocyano-
carbazole)], and the luminescent properties of the ligands
and the complexes in the solid state, in solution at room tem-
perature, and in frozen solution of chloroform at 77 K were
vered.
(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
Germany, 2009)
been reported. Finally, very recently, complexes derived
from insertion into a Pd–Me bond of olefins bearing carb-
Introduction
Carbazole (1) has a conjugated structure with interesting azole substituents have been prepared.[22]
optical and electronic properties. Since the discovery of
Surprisingly, in spite of the well-known tendency of
photoconductivity in poly(N-vinylcarbazole) (PVK) by H. gold(I) to produce luminescent complexes, this metal center
Hoegl,[1] many molecules incorporating the carbazole struc- has been only scarcely explored to produce carbazole-con-
ture have been investigated as light-emitting materials and taining gold complexes. To the best of our knowledge, only
as hole-transporting materials in organic light-emitting de- a gold(I) complex with carbazole behaving as an amido li-
vices (OLEDs).[2] Carbazole derivatives are also used to gand,[9] and a few alkynyl complexes containing carbazole
produce materials displaying luminescence,[3] mesogenic be- spacers, have been reported.[10d,10e] On the basis of our pre-
havior,[4] nonlinear optical properties (NLO),[5] conductiv- vious experience on luminescent gold complexes containing
ity,[6] and photorefractivity.[7]
the isocyanide ligand,[23–25] we decided to functionalize car-
The incorporation of metal centers to carbazole deriva- bazole derivatives with this coordinating function, which is
tives offers the possibility to develop new materials and, a fairly general and strong coordinating linkage towards
depending on the metal, bring on interesting redox, mag- many metals. For short, these new ligands will be referred
netic, optical, and catalytic properties.[8] Thus, a number of to in the text as carbazole isocyanides. We report here the
complexes with the carbazole fragment coordinated as an synthesis of three carbazole isocyanides and their gold(I)
amido ligand through M–N σ-bonds have been reported.[9] complexes.
There are also metal complexes with carbazole-function-
alized ligands: alkynyl,[10] carboxylate,[11] pyridine, isoquin-
oline, fluorene, phenylpyridine,[12,13] carbazole–diphos-
phane,[14] β-diketonate,[15] terpyridine,[16] 1,10-phenan-
throline,[17] benzoimidazole,[18] and imine.[19] A few, η6-
bonded complexes of carbazole derivatives,[20] and polymers
containing metal complexes with a carbazole unit,[21] have
Results and Discussion
Synthesis and Characterization
The syntheses of 9-(4-isocyanophenyl)carbazole (5a) and
3,6-dibromo-9-(4-isocyanophenyl)carbazole (5b) are out-
lined in Scheme 1. Following a literature procedure com-
mercial carbazole (1) was fused with potassium hydrox-
ide,[26,27] and the resulting potassium carbazole salt was
treated with nitrobenzene to give 9-(4-nitrophenyl)carb-
azole (2a). Treatment of 2a with bromine in CHCl3 at 0 °C
afforded 3,6-dibromo-9-(4-nitrophenyl)carbazole (2b). Re-
duction of 2a,b with stannous chloride in refluxing ethanol
[a] IU CINQUIMA Química Inorgánica, Facultad de Ciencias,
Universidad de Valladolid,
47071 Valladolid, Spain
E-mail: espinet@qi.uva.es
Supporting information for this article is available on the
WWW under http://dx.doi.org/10.1002/ejic.200900692.
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P. Espinet, J. A. Miguel et al.
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gave 9-(4-aminophenyl)carbazole (3a) or 3,6-dibromo-9-(4- sponding carbazole isocyanide (Scheme 2). The elemental
1
aminophenyl)carbazole (3b), respectively, which were analyses, yields, relevant IR data, and H and 19F NMR
heated with formic acid in refluxing toluene to prepare the spectroscopic data for the complexes are given in the Exper-
corresponding formanilides (4a,b). Finally, dehydration of imental Section. The IR spectra show one ν(CϵN) absorp-
4a,b with bis(trichloromethyl)carbonate (triphosgene) in tion ca. 2212 cm–1. This is about 90 cm–1 higher than for the
[28,29]
CH2Cl2
yielded 5a,b.
free isocyanide, as an effect of coordination to gold(I).[25,30]
Scheme 2.
1
The H NMR spectra of gold(I) isocyanide complexes
8a,b–10a,b are all very similar (compounds 8a,b are insolu-
1
ble in common organic solvents but their H NMR spectra
could be recorded in deuterated DMSO). The chemical
shifts of the carbazole moiety are essentially unresponsive
to coordination, whereas deshielding is observed for the
aromatic hydrogen atoms of the aryl group bearing the iso-
cyanide function, as reported for arylisocyanide gold(I)
complexes.[25,30,31] For complexes 11 and 12, a small de-
shielding is observed for all the aromatic hydrogen atoms,
which is larger for H1, H2, and H4. The 19F NMR spectra
Scheme 1.
The isocyanide 9-ethyl-3-isocyanocarbazole (7) was pre- of the fluorinated compounds 9a,b and 11 show the charac-
pared similarly, as shown in Scheme 1, starting from com- teristic AAЈMXXЈ signals for C6F5. The 19F NMR spectra
mercial 3-amino-9-ethylcarbazole (6). At room temperature, of 10a,b show two complex multiplets corresponding to an
these carbazole isocyanides are white (for 5a,b) or yellow AAЈXXЈ spin system with JAAЈ = JXXЈ
.
(for 7) solids, not particularly odoriferous, that can be
X-ray quality crystals could be obtained for the more
stored for long periods in the freezer.
soluble complexes 10a and 12, and their molecular struc-
For symmetric ligands 5a,b and their corresponding pre- tures were determined by single-crystal X-ray diffraction
1
cursors, the H NMR spectra (300 MHz) are simple and methods. Their structures and numbering schemes, with se-
show the expected one set of signals, with some bands over- lected bond lengths and angles, are shown in Figures 1 and
lapping. The spectra are obviously simpler for the bromi- 2, respectively. The data collection and refinement param-
nated derivatives. Thus, the aromatic hydrogen atoms of 5b eters are detailed in the Experimental Section. Compound
display three resonances as expected: a doublet (J = 8.7 Hz) 10a (Figure 1) crystallizes in the monoclinic space group
for H1 and H8, a doublet of doublets (J = 8.7, 1.9 Hz) for P21/c, with four formula units per unit cell. All the bond
H2 and H7, and a doublet (J = 1.9 Hz) for H4 and H5. In lengths are within normal ranges. The gold coordination
addition, an AAЈXXЈ system is observed in all compounds is almost perfectly linear, with bond angles C(1)–Au–C(21)
for the hydrogen atoms of the 1,4-substituted ring. The aro- 179.8° and N(1)–C(1)–Au 179.7°. The steric hindrance be-
matic resonances for less symmetric 7 are more complex tween the hydrogen atoms of the carbazole and the aryl ring
and were assigned with the help of COSY. For the three forces a nonplanar conformation between the plane of the
isocyanides (i.e., 5a,b and 7) one ν(CϵN) IR absorption is phenyl ring and the carbazole group. For instance, 9-phen-
observed at ca. 2125 cm–1.
ylcarbazole shows two angles of 78.11 and 54.18°[32] and 9-
The gold(I) compounds [AuX(CNR)] (8a,b–10a,b; 11; (4-cyanophenyl)carbazole displays an angle of 46.25°.[33]
and 12) were easily prepared in good yield, as pale yellow The dihedral angle 41.4° found for 10a is the smallest angle
solids, by 1:1 reaction in CH2Cl2 of [AuX(tht)] (tht = tetra- reported for 9-(phenyl)carbazole derivatives. The shortest
hydrothiophene; X = Cl, C6F5, C6F4-OEt-p) with the corre- Au–Au intermolecular distance in the crystal is 5.712 Å,
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Gold(I) Complexes with Carbazole-Derived Ligands
which clearly excludes the existence of any Au···Au interac- Photophysical Studies
tions. The shortest F–F distance, larger than 3 Å, also ex-
cludes intermolecular fluoro–fluoro interactions.[25]
The UV/Vis absorption and excitation spectra of the free
isocyanides and their corresponding gold(I) complexes are
summarized in Table 1. The UV/Vis spectra are complex,
with multiple overlapping broad bands. Yet some clear dif-
ferences can be recognized for the three families derived
from 5a,b and 7, respectively.
Ligand 5a and their complexes 8a,b–10a,b show very
similar UV absorptions (Figure 3a). They are dominated by
a strong absorption at ca. 250 nm (with a more or less de-
fined shoulder), and show other broad absorptions in the
ranges 275–300 and 300–375 nm. The main differences ob-
served upon complexation are moderate intensity changes
and a redshift in the band that appears at 317 nm in free
ligand 5a relative to 340 nm in gold complexes 8a–10a. Be-
cause metal–ligand charge transfers are known to appear
at shorter wavelengths, generally below 250 nm,[34] all the
absorptions are assigned to phenyl-localized π–π* transi-
tions,[35] dominated by a strong absorption band at ca.
243 nm and accompanied by other less-intense absorptions
at higher wavelengths. The changes observed for the com-
plexes should be deemed to polarizability changes upon in-
corporation of the gold center.
Figure 1. Crystal structure of [Au(C6F4OEt-p)(CϵNC6H4-
NC12H8)] (10a). The ellipsoids are shown at 30% probability (H
atoms omitted for clarity). Selected bond lengths [Å]: Au(1)–C(1)
1.965(5), Au(1)–C(21) 1.965(5), C(1)–N(1) 1.153(6), N(1)–C(2)
1.405(6). Selected angles [°]: C(1)–Au(1)–C(21) 179.8(2), N(1)–
C(1)–Au(1) 179.7(5), C(1)–N(1)–C(2) 178.1(6).
Compound 12 (Figure 2) crystallizes in the triclinic space
¯
group P1, with two formula units per unit cell. The gold
coordination is almost linear [angle C(1)–Au–C(11) 176.6°].
The bond lengths are comparable to those of 10a and re-
lated gold isocyanide complexes.[23,25] The molecules of 12
pack antiparallel, with no significant π–π interaction be-
tween the aromatic fragments. The shortest Au–Au inter-
molecular distance is 6.703 Å.
Brominated free ligand 5b and their complexes 8b–11b
(Figure 3b) show essentially identical behavior, but in this
case energy of the absorption at ca. 350 nm, which is al-
ready there in the free ligand, is insensitive to coordination
and only its intensity increases.
Finally, the absorption spectra of 7, 11, and 12 (Fig-
ure 3c) show clearly different behavior. The spectra have in
common with the previous ones, the intense band at ca.
245 nm, but the most prominent band (with a shoulder)
appears in the 275–300 range. In this case, where the metal
is directly coordinated to the carbazole ring, this band (at
ca. 275 nm) and its shoulders (at ca. 262 and 290 nm) are
very sensitive to coordination and undergo a noticeable
change in intensity and energy on going from ligand 7 to
their complexes 11 and 12, and in contrast to the modest
effect observed for 8a,b, a redshift is observed. This is not
unexpected, as one can reasonably expect larger polarizabil-
Figure 2. Crystal structure of [Au(C6F5)(9-ethyl-3-isocyanocarb-
azole)] (12). The ellipsoids are shown at 30% probability (H atoms
omitted for clarity). Selected bond lengths [Å]: Au(1)–C(11)
1.958(6), Au(1)–C(1) 2.018(5), C(11)–N(1) 1.166(7), N(1)–C(15)
1.381(6). Selected angles [°]: C(11)–Au(1)–C(1) 176.61(17), N(1)–
C(11)–Au(1) 176.0(4), C(11)–N(1)–C(15)174.6(5).
Table 1. UV/Vis absorption and emission spectroscopic data for ligands 5a,b and 7, and their gold complexes in chloroform at 298 K,
and excitation and emission data in KBr (at 298 K) and in frozen CHCl3 solution (at 77 K).
λmax / nm (104 ε / dm3mol–1cm–1)
298 K (KBr)
77 K (CHCl3)
λex / nm
λem / nm
λex / nm
λem / nm
5a
5b
7
244 (4.5), 293 (1.9), 317 (1.4), 337 (0.9)
243 (6.8), 303 (2.9), 355 (0.6)
244 (3.2), 277 (4,5), 290 (sh., 1.4), 337 (0.3), 353 (0.3)
242 (6.7), 288 (2.6), 339 (1.7)
241 (9.1), 275 (3.5), 340 (2.2), 347 (2.1)
246 (9.7), 284 (4.4), 340 (3.6)
243 (8.7), 293 (2.7), 303 (2.9), 342 (1.7), 354 (1.8)
243 (10.0), 302 (2.1), 354 (2.3)
244 (3.9), 265 (1.9), 290 (1.0), 303 (1.0), 345 (1.1), 354 (1.1)
244 (2.6), 275 (sh., 2.8), 290 (5.1), 320 (1.7), 337 (sh., 0.9), 353 (sh., 0.3)
244 (3.2), 275 (sh., 2.8), 290 (5.3), 319 (1.5), 337 (sh., 0.8) 353 (sh., 0.3)
347
365
330
381
327
380
394
391
365
389
400
368
391
356
439
356, 375, 394
463 (sh.), 482
530
325
335
380
388
391
485
523
525
8a
9a
10a
8b
9b
10b
11
12
543
445, 469
460, 508
489, 516
461
350
399
475 (sh.), 527
457, 510 (sh.)
456, 474[a]
322[a]
380
447, 525
498
[a] Measured at 77 K.
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KBr pellet at room temperature displays a well-resolved vi-
brational pattern that could be due to the C=C bond, af-
fording a central band at 365 nm flanked by two shoulders
(≈1200 cm–1; Supporting Information, Figure S1). The
emission bands of 8a–10a are shifted, by at least 120 nm
(6700 cm–1), to longer wavelengths from their position in
the corresponding free ligand. The deshielding observed in
1
the H NMR spectra for the hydrogen atoms of the aryl
ring, when the ligands are coordinated to gold, suggests
that the isocyano substituent becomes more electron with-
drawing when its carbon lone pair is donated to gold, thus
enhancing the charge separation in the carbazole–phenyl
system. In the solid state (KBr pellets) the emission spectra
of the gold complexes show broad emission bands in the
range 400–600 nm. There is a clear shift to lower energy
from chloride derivative 8a (485 nm) to pentafluorophenyl
Figure 3. Absorption spectra of ligands 5a (a), 5b (b), 7 (c), and
their complexes recorded in CHCl3 solution (10–4 to 10–5 ) at
room temperature.
ity changes in the molecule when gold is coordinated to a
carbazole aryl ring.
The emission spectra of the ligands and the complexes
were measured in the solid state (KBr pellets or dispersion)
at room temperature and in frozen chloroform at 77 K. On
the basis of the Stoke shifts between absorption and emis-
sion for ligands 5a and 7 and (lower than 3000 cm–1) the
luminescence observed is assigned to π–π* fluorescence. For
ligand 5b and all the complexes, the lifetimes seem to be
roughly in the lower limit of detection of our instrument
(10 µs), suggesting phosphorescence.
Ligand 5a and its complexes 8a–10a are luminescent at
298 K in the solid state, but not in solution at room tem-
perature (Table 1). For ligand 5a, the emission spectrum in (c), and their complexes in frozen chloroform solution at 77 K.
Figure 4. Normalized emission spectra of ligands 5a (a), 5b (b), 7
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Gold(I) Complexes with Carbazole-Derived Ligands
derivative 9a (523 nm) or tetrafluorophenyl derivative 10a cyanophenyl)carbazole, 3,6-dibromo-9-(4-isocyanophenyl)-
(525 nm), which follows the order of decreasing electrone- carbazole, and 9-ethyl-3-isocyanocarbazole show a redshift
gativity of the X substituents on gold.[36] At 77 K in frozen in the emissions relative to that of the corresponding free
chloroform solution (Figure 4) the luminescence is, qualita- ligand, regardless of the position of attachment of the gold
tively, more intense and similar shifts are observed.
fragment in the carbazole unit. In general, the emission
A different behavior was found for brominated ligand 5b, wavelength is sensitive to the X substituents on gold. The
which is nonluminescent at room temperature in the solid presence of electron-withdrawing substituents in the ligand
state. As for the corresponding complexes under the same 3,6-dibromo-9-(4-isocyanophenyl)carbazole quenches the
conditions, complex 8b is practically nonluminescent; 9b luminescence observed for 9-(4-isocyanophenyl)carbazole,
and 10b show some luminescence but are clearly less lumi- which is somewhat recovered upon complexation to gold.
nescent than their non-brominated analogues. The detri-
mental effect for luminescence of attaching electron-with-
Experimental Section
drawing substituents to conjugated molecules has been no-
ticed and discussed before.[37]
General Procedures: C, H, and N analyses were carried out with a
Perkin–Elmer 2400 microanalyzer. IR spectra were recorded with
a Perkin–Elmer FT-1720X spectrometer by using nujol mulls be-
tween polyethylene films. UV/Vis data were recorded with a Shim-
adzu UV-1603 spectrophotometer in chloroform solutions 10–4 to
10–5 , and luminescence data were recorded with a Perkin–Elmer
LS-55 spectrometer. NMR spectra were run at room temperature
with Bruker AC-300 or ARX-300 spectrophotometers
In frozen chloroform, free ligand 5b is luminescent, but
it exhibits a broad band (λmax = 439 nm) with an important
redshift relative to that of 5a, and bigger separation be-
tween the maxima of excitation (λmax = 381 nm) and emis-
sion. These features would fit better with phosphorescence
than with fluorescence. Moreover, the quenching of the ob-
served luminescence, in the solid state and in solution
(which does not occur in 5a), is better understood by the
heavy atom (Br) effect in 5b, which facilitates intersystem
crossing (ISC) to give phosphorescence, easily quenched by
the solvent molecules at room temperature. The corre-
sponding gold(I) complexes, including 8b, show low lumi-
nescence at low temperature (two overlapped bands in the
range 400–600 nm, Table 1). In contrast to the emission
spectra of 5a and their complexes, we find that the gold
complexes of 5b show just a modest λmax shift from the free
ligand, suggesting a ligand-dominated emissive state.
Ligand 7 is the only ligand that is luminescent in solution
in CHCl3 at room temperature, and it displays one emission
band at 375 nm; this emission also appears in the solid state
at 391 nm and can be assigned to an intraligand π–π*
charge transfer similar to the carbazole emission at
360 nm.[38] At low temperature in frozen chloroform solu-
tion, 7 displays a well-resolved vibronic structure with a
vibrational spacing of ≈1350 cm–1 (Figure 4c). Only com-
plex 12 is luminescent in the solid state at room tempera-
ture, but both 11 and 12 display two overlapping emission
bands at 77 K (Supporting Information, Figures S4 and
S5). As for the absorption spectra, the emission bands are
shifted to longer wavelengths (more than 5000 cm–1) on go-
ing from ligand 7 to its complexes 11 and 12. The change
in the X substituent on gold has a moderate effect on the
luminescence: in comparison to the pentafluorophenyl de-
rivative, the chloride derivative is less luminescent (nonlu-
minescent at room temperature) and shows a lower redshift
from the ligand (600 cm–1 less than C6F5) in frozen chloro-
form solution. Similar redshifts have been observed in other
carbazole derivatives with substitutions at the 3-position.[39]
1
(300.13 MHz for H and 282.4 MHz for 19F). Literature methods
were used to prepare 9-(4-aminophenyl)carbazole (4a) and 3,6-di-
bromo-9-(4-aminophenyl)carbazole (4b) from commercial carba-
zole.[26–27] Preparation procedures and physical data of the new
compounds are given below. When analogous ligands and com-
plexes were prepared in the same way only one preparation is de-
scribed.
9-(4-Isocyanophenyl)carbazole (5a): The procedure described by
Ugi was followed,[28] but by using triphosgene as dehydrating agent.
A flask provided with a Dean–Stark apparatus was charged with a
solution of 9-(4-aminophenyl)carbazole (2.0 g, 7.74 mmol) in tolu-
ene (50 mL). Formic acid (1.5 mL, 98%) was added. The resulting
solution was heated at reflux for 2 h and then cooled to room tem-
perature. The solvent was removed under vacuum, and the crude
product 9-(4-formanilide)carbazole was obtained (2.18 g, 98%).
The crude product was sufficiently pure for use in the next reaction.
To a solution of the formanilide (2.0 g, 6.9 mmol) and triethyl-
amine (2.9 mL, 20.7 mmol) in CH2Cl2 (20 mL) was added dropwise
a solution of triphosgene (0.7 g, 2.3 mmol) in CH2Cl2 (15 mL). The
mixture was stirred for 1 h, and the solvent was removed under
reduced pressure. The resulting residue was purified by chromatog-
raphy (silica gel; CH2Cl2/hexane, 3:1), and the solvent was evapo-
rated to obtain the product as a yellow solid (1.34 g, 71%).
C19H12N2 (268.32): calcd. C 85.05, H 4.51, N 10.44; found C 84.77,
1
H 4.65, N 10.12. H NMR (300.13 MHz, CDCl3): δ = 8.16 (m, 2
H), 7.63 (s, AAЈXXЈ spin system, 4 H), 7.42 (m, 4 H) 7.33 (m, 2
H) ppm. IR (nujol): ν = 2124 [ν(CϵN)] cm–1.
˜
3,6-Dibromo-9-(4-isocyanophenyl)carbazole (5b): Yield: 0.854 g
(89%). C19H10Br2N2 (426.11): calcd. C 53.56, H 2.37, N 6.57;
1
found C 53.46, H 2.54, N 6.64. H NMR (300.13 MHz, CDCl3): δ
= 8.19 (d, 4JH,H = 1.9 Hz, 2 H, H4, H5), 7.64, 7.58 (AAЈXXЈ, 3JH,H
3
4
= 8.7 Hz, 4 H, C6H4), 7.53 (dd, JH,H = 8.7 Hz, JH,H = 1.9 Hz, 2
H, H2, H7), 7.24 (d, 3JH,H = 8.7 Hz, 2 H, H1, H8) ppm. IR (nujol):
ν = 2125 [ν(CϵN)] cm–1.
˜
9-Ethyl-3-isocyanocarbazole (7): Yield: 1.645 (89%). C15H12N2
(220.27): calcd. C 81.79, H 5.49, N 12.72; found C 81.50, H 5.24,
4
N 12.27. 1H NMR (300.13 MHz, CDCl3): δ = 8.11 (d, JH,H
=
Conclusions
1.5 Hz, 1 H, H4), 8.07, (d, 3JH,H = 7.6 Hz, 1 H, H5), 7.54 (m, 1 H,
3
4
In conclusion, all the gold complexes [AuX(CN-carb-
H7), 7.47 (dd, JH,H = 8.5 Hz, JH,H = 1.6 Hz, 1 H, H2), 7.44 (d,
azole)] (X = Cl, C6F5, C6F4-OEt-p) derived from 9-(4-iso- 3JH,H = 8.3 Hz, 1 H, H8), 7.36 (d, JH,H = 8.4 Hz, 1 H, H1), 7.29
3
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3
3
(m, 1 H, H6), 4.38 (q, JH,H = 7.2 Hz, 2 H, CH2), 1.45 (t, JH,H
=
–20 °C. Yield: 0.111 g (45%). C27H17AuF4N2O (658.41): calcd. C
49.25, H 2.60, N 4.25; found C 49.06, H 2.57, N 4.19. 1H NMR
(300.13 MHz, CDCl3): δ = 8.17 (m, 2 H), 7.81 (m, 4 H), 7.47 (m,
7.3 Hz, 3 H, CH ) ppm. IR (nujol): ν = 2121 [ν(CϵN)] cm–1.
˜
3
[AuCl{9-(4-isocyanophenyl)carbazole}] (8a): To
a solution of
3
4 H), 7.37 (m, 2 H), 4.24 (q, JH,H = 7.0 Hz, 2 H, CH2), 1.41 (t,
[AuCl(tht)] (0.11 g, 0.36 mmol) in dichloromethane (30 mL) was
added 5a (0.10 g, 0.37 mmol). After the mixture had been stirred
for 1 h, the solvent was evaporated to ca. 5 mL under reduced pres-
sure. Addition of hexane (20 mL) afforded 8a as a pale yellow solid,
which was filtered off, washed with hexane and vacuum dried
3JH,H = 7.0 Hz, 3 H, CH3) ppm. 19F NMR (282.4 MHz, CDCl3):
δ = –118.1, –157.3 (m, AAЈXXЈ, JAX + JAXЈ = 17.8 Hz) ppm. IR
(KBr): ν = 2207 [ν(CϵN)] cm–1.
˜
[AuCl{3,6-dibromo-9-(4-isocyanophenyl)carbazole}] (8b): Yield:
(0.114 g, 63%). C19H12AuClN2 (500.74): calcd. C 45.57, H 2.42, N
0.0983 g (63%). C19H10AuBr2ClN2 (658.53): calcd. C 34.65, H 1.53,
1
5.59; found C 45.53, H 2.27, N 5.76. H NMR (300.13 MHz, [D6]- N 4.25; found C 34.92, H 1.62, N 4.17. 1H NMR (300.13 MHz,
4
DMSO): δ = 8.26 (m, 2 H), 7.47 (m, 4 H), 7.34 (m, 2 H), 8.14, 7.92 [D6]acetone): δ = 8.61 (d, JH,H = 1.9 Hz, 2 H, H4, H5), 8.15, 7.91
3
3
3
(AAЈXXЈ, JH,H = 7.7 Hz, 4 H, C H ) ppm. IR (nujol): ν = 2213
(AAЈXXЈ, JH,H = 8.8 Hz, 4 H, C6H4), 7.62 (dd, JH,H = 8.8 Hz,
˜
6
4
[ν(CϵN)], 345 [ν(Au–Cl)] cm–1.
4JH,H = 1.9 Hz, 2 H, H2, H7), 7.41 (d, JH,H = 8.8 Hz, 2 H, H1,
3
H8) ppm. IR (nujol): ν = 2210 [ν(CϵN)], 356 [ν(Au–Cl)] cm–1.
˜
[Au(C6F5){9-(4-isocyanophenyl)carbazole}] (9a): The method was
the same as that above but with the use of [Au(C6F5)(tht)]. Yield:
0.186 g (87%). C25H12AuF5N2 (632.34): calcd. C 47.49, H 1.91, N
4.43; found C 47.82, H 1.86, N 4.80. 1H NMR (300.13 MHz,
CDCl3): δ = 8.16 (m, 2 H), 7.46 (m, 4 H), 7.36 (m, 2 H), 7.81 (s, 4
H, C6H4) ppm. 19F NMR (282.4 MHz, CDCl3): δ = –116.4 (m, 2
F, Fo), –157.6 (t, 3JF,F = 17.9 Hz, 1 F, Fp), –162.7 (m, 2 F, Fm) ppm.
[Au(C6F5){3,6-dibromo-9-(4-isocyanophenyl)carbazole}] (9b): Yield:
0.0576 g (66%). C25H10AuBr2F5N2 (790.13): calcd. C 38.00, H
1.28,
(300.13 MHz, CDCl3): δ = 8.22 (d, JH,H = 1.9 Hz, 2 H, H4, H5),
N 3.55; found C 37.95, H 1.15, N
3.77. 1H NMR
4
3
3
7.84, 7.74 (AAЈXXЈ, JH,H = 8.8 Hz, 4 H, C6H4), 7.56 (dd, JH,H
4
3
= 8.8 Hz, JH,H = 1.9 Hz, 2 H, H2, H7), 7.29 (d, JH,H = 8.8 Hz, 2
IR (nujol): ν = 2211 [ν(CϵN)] cm–1.
H, H1, H8) ppm. 19F NMR (282.4 MHz, CDCl3): δ = –116.5 (m,
˜
2 F, Fo), –157.5 (t, JF,F = 20.2 Hz, 1 F, Fp), –162.6 (m, 2 F, Fm)
3
[Au(C6F4-OEt-p){9-(4-isocyanophenyl)carbazole}] (10a): To a solu-
tion of HC6F4-OEt-p (0.052 mL, 0.373 mmol) in dried diethyl ether
(25 mL) was added a solution of BuLi (1.6  in hexane, 0.233 mL,
0.373 mmol) at –78 °C under an atmosphere of nitrogen. After the
solution was stirred for 1 h at –50 °C, solid [AuCl(tht)] (0.1196 g,
0.373 mmol) was added at –78 °C, and the reaction mixture was
slowly brought to 10 °C (3 h). Then, a few drops of water were
added, and the solution was filtered through anhydrous Na2SO4
and 5a (0.100 g, 0.373 mmol) was added to the solution obtained.
After stirring for 1 h, the solution was filtered through Kieselgur
and silica gel. The solvent was removed, and the pale yellow solid
obtained was recrystallized from dichloromethane/hexane at
ppm. IR (nujol): ν = 2208 [ν(CϵN)] cm–1.
˜
[Au(C6F4-OEt-p){3,6-dibromo-9-(4-isocyanophenyl)carbazole}] (10b):
Yield: 0.111 g (29%). C27H15AuBr2F4N2O (816.20): calcd. C 39.73,
H 1.85, N 3.43; found C 39.38, H 2.19, N 3.13. 1H NMR
4
(300.13 MHz, CDCl3): δ = 8.23 (d, JH,H = 1.8 Hz, 2 H, H4, H5),
3
3
7.85, 7.73 (AAЈXXЈ, JH,H = 8.6 Hz, 4 H, C6H4), 7.56 (dd, JH,H
4
3
= 8.8 Hz, JH,H = 1.9 Hz, 2 H, H2, H7), 7.33 (d, JH,H = 8.8 Hz, 2
3
3
H, H1, H8), 4.22 (q, JH,H = 7.0 Hz, 2 H, CH2), 1.37 (t, JH,H
=
7.0 Hz, 3 H, CH3) ppm. 19F NMR (282.4 MHz, CDCl3): δ =
–118.2, –157.3 (m, AAЈXXЈ, JAX + JAXЈ = 17.9 Hz) ppm. IR
(KBr): ν = 2212 [ν(CϵN)] cm–1.
˜
Table 2. Crystal and structure refinement data for 10a and 12.
10a
12
Empirical formula
Formula weight
C27H17AuF4N2O
658.39
C21H12AuF5N2
584.29
Temperature / K
Wavelength / Å
298(2)
0.71073
298(2)
0.71073
Crystal system
Space group
monoclinic
P21/c
triclinic
P1
¯
a / Å
b / Å
c / Å
α / °
11.4625(18)
10.6421(16)
18.759(3)
90
99.327(3)
90
2258.1(6)
4
1.937
7.8358(9)
9.7161(11)
13.1481(15)
98.166(2)
99.620(2)
106.137(2)
929.08(18)
2
β / °
γ / °
V / Å3
Z
Dcalcd. / gcm–3
2.089
7.975
552
Absorption coefficient / mm–1
F(000)
6.572
1264
Crystal size / mm
θ range for data collection / °
Reflections collected
Independent reflections
Absorption correction
Maximum and minimum transmission factor
Data, restraints, parameters
Goodness-of-fit on F2
R1 [IϾ2σ(I)]
0.24ϫ0.09ϫ0.03
1.80 to 23.29
10775
0.12ϫ0.10ϫ0.04
2.23 to 23.28
5775
3251
3789
SADABS
1.000000 and 0.608741
3251, 0, 317
1.022
0.0229
0.0581
SADABS
1.000000 and 0.539600
3789, 0, 263
1.021
0.0265
0.0666
wR2 (all data)
5404
www.eurjic.org
© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2009, 5399–5406

Gold(I) Complexes with Carbazole-Derived Ligands
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(d, JH,H = 1.9 Hz, 1 H, H4), 8.10 (d, JH,H = 8.8 Hz, 1 H, H1),
7.59 (m, 2 H), 7.49 (d, 3JH,H = 8.4 Hz, 1 H), 7.46 (d, 3JH,H = 8.5 Hz,
3
1 H), 7.36 (m, 1 H), 4.42 (q, JH,H = 7.2 Hz, 2 H, CH2), 1.47 (t,
3JH,H = 7.2 Hz, 3 H, CH ) ppm. IR (nujol): ν = 2222 [ν(CϵN)]
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3
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˜
[ν(CϵN)] cm–1.
X-ray Structures: Crystal structure refinement data for 10a and 12
are given in Table 2. Data were recorded with a Bruker AXS
SMART 1000 CCD diffractometer, using φ and ω scans, Mo-Kα
radiation (λ = 0.71073 Å), graphite monochromator, and T =
298 K. Raw frame data were integrated with SAINT[40] program.
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non-hydrogen atoms were refined anisotropically. Hydrogen atoms
were set in calculated positions and refined as riding atoms, with a
common thermal parameter. All calculations were made with
SHELXTL.
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Supporting Information (see footnote on the first page of this arti-
cle): Emission spectra of 5a, 8a, 9a, 10a, 9b, 10b, 7, 11, and 12.
Acknowledgments
We thank Dr. Julio Gómez for some spectral measurements. The
Spanish Comisión Interministerial de Ciencia y Tecnología [INTE-
CAT Consolider Ingenio 2010 (CSP2006-0003) and Project
CTQ2008-03954] and the Junta de Castilla y León (Project
VA012A08 and GR169) are thanked for financial support.
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