Synthesis, photophysical properties, and molecular aggregation of gold(I) complexes containing carbon-donor ligands

Article abstract of DOI:10.1002/asia.201000499

A series of gold(I) complexes with N-heterocyclic carbene (NHC) and acetylide ligands, namely [Au(NHC¹)(C≡CAr)] (NHC ¹=1-(9-anthracenylmethyl)-3-(n)-butylimidazol-2-ylidene; 1b-1g), [Au(NHC²)(C≡CAr)] (NHC²=1,3-diethylimidazol-2- ylidene; 2b-2f) and [Au(C≡NAr)₂]⁺ (C≡NAr=arylisocyanide; 3a-3f) have been synthesized. At room temperature, most of these gold(I) complexes are emissive in the solid state and in solutions with lifetimes in the nanosecond to submicrosecond regime. The emissions of complexes 1b-1g in solutions are assigned to ¹π-π* excited states of the NHC ligand, while that of 2b-2f and 3a-3f are phosphorescent in nature. The intriguing solvatochromism of complex 3a was also investigated. Complexes 1b, 1d, 3a, and 3e aggregate into crystalline nanowires in freshly prepared THF/water dispersions. The X-ray crystallographic data reveal that 1b and 1d possess intermolecular π-π and C-H ... π interactions; while 3a was found to display intermolecular gold(I) ... π interactions. Copyright

Full text of DOI:10.1002/asia.201000499

FULL PAPERS
DOI: 10.1002/asia.201000499
Synthesis, Photophysical Properties, and Molecular Aggregation of Gold(I)
Complexes Containing Carbon-Donor Ligands
Andy Lok-Fung Chow, Man-Ho So, Wei Lu,* Nianyong Zhu, and Chi-Ming Che*[a]
Dedicated to Professor Eiichi Nakamura on the occasion of his 60th birthday
Abstract: A series of gold(I) complexes
with N-heterocyclic carbene (NHC)
and acetylide ligands, namely [Au-
solid state and in solutions with life-
times in the nanosecond to submicro-
second regime. The emissions of com-
plexes 1b–1g in solutions are assigned
to 1p–p* excited states of the NHC
ligand, while that of 2b–2 f and 3a–3 f
are phosphorescent in nature. The in-
triguing solvatochromism of complex
3a was also investigated. Complexes
1b, 1d, 3a, and 3e aggregate into crys-
talline nanowires in freshly prepared
THF/water dispersions. The X-ray crys-
tallographic data reveal that 1b and 1d
A
U
(NHC1 =1-(9-an-
1b–1g),
2b–2 f)
[AuACTHUNGETRNNUG
(NHC2)-
ꢀ
N
possess intermolecular p–p and C
zol-2-ylidene;
(CꢁNAr)2]+
and
[Au-
H···p interactions; while 3a was found
to display intermolecular gold(I)···p in-
teractions.
E
(CꢁNAr =arylisocya-
Keywords: gold · isocyanide · lumi-
nescence · nanowires · n-heterocy-
clic carbene
nide; 3a–3 f) have been synthesized. At
room temperature, most of these
gold(I) complexes are emissive in the
Introduction
scale electronics and molecular devices.[10–12] It has been
known that self-assembly of organometallic and organic
molecules into micrometer- and nanometer-sized structures
could be a useful means for the preparation of materials
with extraordinary properties, for these self-assembly reac-
tions and non-covalent intermolecular interactions are used
to construct micro- and nano-sized molecular assemblies
using weak hydrogen bonding, p–p, and van der Waals inter-
actions.[13–19] However, reports about nanorods/nanowires in-
volving organogold(I) are sparse.
Luminescent gold(I) complexes with carbon-donor ligands
have attracted considerable interest in the past decades.[20]
Both N-heterocyclic carbene (NHC) and isocyanide ligands
are good s-donor ligands, NHC is ~120 kcalmolꢀ1 more
stable than simple methylidene, allowing the convenient use
of NHC ligand in preparative organometallic chemistry.[21–28]
Metal isocyanide complexes are of long-standing interest in
organometallic chemistry, catalysis, diagnostic medi-
cines,[29–30] and supramolecular science.[31–32] In literature, or-
One-dimensional metal nanorods/nanwires have attracted
considerable attention owing to their unique electronic,
magnetic, and optical properties,[1–3] they also possess poten-
tial applications in nanoelectronics, photonics, and sen-
sors.[4–6] Gold nanorods/nanowires are of particular interest
owing to their chemical inertness and good biocompatibility,
indeed gold nanorods/nanowires are expected to play a cru-
cial role in biomedical research such as optical imaging and
photochemical treatment.[7–9] In the literature, there have
been extensive studies revealing that gold nanorods/nano-
wires possess self-assembly ability which make them func-
tion as important building blocks for the linkage of nano-
[a] Dr. A. L.-F. Chow, Dr. M.-H. So, Dr. W. Lu, Dr. N. Zhu,
Prof. Dr. C.-M. Che
Department of Chemistry
Institute of Molecular Functional Materials
and HKU-CAS Joint Laboratory on New Materials
The University of Hong Kong
Pokfulam Road, Hong Kong (China)
Fax : (+852)28571586
ꢀ
ꢀ
ganogold(I) polymers such as [R-CꢁC-Au-CꢁN-R’]n (R
and R’ are aryl groups),[33–34] are used as building blocks in
supramolecular chemistry.[31] In this paper, we present the
synthesis of a series of luminescent gold(I) complexes con-
taining NHC, acetylide, and/or isocyanide ligands (Cꢁ
E-mail: luwei@hku.hk
cmche@hku.hk
NAr), namely [Au
G
(CꢁCAr)] and [Au
ACHTUNGTRENNUNG
Supporting information for this article is available on the WWW
under http://dx.doi.org/10.1002/asia.201000499.
respectively Most of these complexes are emissive in both
.
544
ꢀ 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Asian J. 2011, 6, 544 – 553

solid state and in solution at room temperature. Two gold(I)
bis-isocyanide complexes 3a and 3e were found to form
nanowires/nanobelts with diameter ~30 nm and 150 nm, re-
spectively; while nanowires of complexes 1b and 1d ([Au-
A
E
butylimidazol-2-ylidene) with length extending over 5.6 mm
and 2.8 mm and diameters of 120 nm and 45 nm, respectively,
were formed in THF and H2O mixture. The intermolecular
ꢀ
p–p, C H···p, and cationic gold(I)···p interactions between
aryl rings is suggested to play a role to direct the growth of
the nanostructures of these gold(I) complexes.
Scheme 3. Synthesis and chemical structures of complexes 3a–3 f.
Results and Discussion
larly synthesized as complexes 1b–1g, but with N,N’-diethy-
limidazolium iodide (P2) used as the starting material. How-
Synthesis
ever, the isolation of [Au
pure solid form was unsuccessful and only a yellow oil with
low purity could be obtained. All of the [Au(NHC)-
(CꢁCAr)] complexes could be purified with the use of a
ACHTUNGTRENNUNG
The synthesis and structures of the gold(I) complexes (1b–
1g, 2a–2 f, and 3a–3 f) are depicted in Schemes 1–3. [Au-
ACHTUNGTRENNUNG
(NHC1)Cl] (1a) was obtained in 86% yield. Complexes 1b–
ACHTUNGTRENNUNG
1g were similarly prepared except with an extra addition of
arylacetylene and NaOH in CH3CN. The use of a mixed
CH2Cl2/CH3CN solvent system is crucial to the high product
cannula, simple filtration, and recrystallization. For the syn-
thesis of para-substituted-2,6-diisopropylphenylisocyanide li-
gands P5–P7 (P5: para-group=Br; P6: CꢁC-1-pyrenyl; P7:
CꢁCH), 4-bromo-2,6-diisopropylaniline was used as a start-
ing material; the synthetic procedures of all isocyanides are
given in the Supporting Information (Schemes S1 and S2).
Ligands of P3 (2,6-dimethyl-4-dimethylaminophenylisocya-
nide) and P6 [1-(4-isocyano-3,5-diisopropyl-phenylethynyl)-
pyrene] are new arylisocyanides. All gold(I) complexes are
stable in solid form at room temperature and can be stored
for months without decompositon; they display a good solu-
bility in CH2Cl2, alcohols, acetone, DMF, THF, and CH3CN,
but are insoluble in Et2O, ethyl acetate, n-pentane, and n-
hexane. The detailed synthetic procedures of ligands P1–P8
and all of the gold(I) complexes can be found in the Sup-
porting Information.
yield of [Au
was obtained in a relatively lower yield of 64.3%. Other
gold(I) NHC complexes of [Au
(NHC2)
(NHC1)
N
A
E
1,3-diethylimidazol-2-ylidene; complexes 2b–2 f) were simi-
Absorption Spectroscopy
The electronic absorption spectra of 1b–1g in CH2Cl2 at
298 K display intense absorptions at 248–258 and 350–
390 nm (Table 1, Figure 1a, and Figure S1 in the Supporting
Information). These absorption bands are similar to those of
the precursor P1 and 1a in band shape and absorption peak
maximum; thus, the absorption bands with lmax 250ꢂ1,
258ꢂ1, 336ꢂ10, 372ꢂ1, and 390 nm are assigned to a p–p*
transition involving the anthracene ring. However, 1b–1g
show additional absorption peaks at lmax 280–320 nm, which
do not present in the precursor ligand P1 and complex 1a.
These bands are assigned to p–p* transition(s) involving the
acetylide ligand. The absorption bands with lmax 305 nm in
1c and 313 nm in complexes 1 f–1g do not present in 1a–1b
and 1d–1e. The intense absorption band at lmax 305 nm is
assigned to a p–p* transition of 4-cyano-phenylacetylide;
Scheme 1. Synthesis and chemical structures of complexes 1b–1g.
while the peak at lmax 313 nm (1 f: e~32300 dm3 molꢀ1 cmꢀ1
;
1g: e~33000 dm3 molꢀ1 cmꢀ1) arises from a p–p* transition
of 6-methoxy-naphthalenyl-2-acetylide and phenanthrene-9-
acetylide, respectively. The absorption spectra of 2b–2 f in
Scheme 2. Synthesis and chemical structures of complexes 2b–2 f.
Chem. Asian J. 2011, 6, 544 – 553
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545

W. Lu, C.-M. Che et al.
FULL PAPERS
Table 1. Absorption and emission data of gold(I) complexes.
[a]
labs/nm [e/ꢁ104 dm3 molꢀ1 cmꢀ1
]
Solid (298 K)
Solid (77 K)
Fluid Solution
(298 K)
Glassy Solution (77 K)
lem (t [ms])[b]
451 (<0.1)
lem (t [ms])[b]
lem (t [ms]); F[a]
lem (t [ms])[c]
1b 250 (8.5), 258 (12.4), 285 (2.39), 335 (0.49), 351 (0.86),
371 (1.06), 390 (1.04)
494 (0.21)
394, 417 (0.007), 438; 399, 415 (0.28), 441
0.05
1c 250 (10.5), 259 (13.8), 285 (3.38), 289 (3.89), 305 (4.98),
336 (0.68), 352 (1.03), 371 (1.36), 390 (1.28)
1d 251 (10.5), 258 (13.4), 287 (2.51), 299 (1.74), 336 (0.57),
352 (0.90), 371 (1.2), 390 (1.14)
1e 250 (8.83), 258 (12.5), 279 (2.54), 284 (2.94), 296 (4.15),
313 (3.96),
509 (<0.1)
468 (<0.1)
495 (<0.1)
533 (0.18)
480 (0.18)
505 (0.17)
395, 417 (0.007), 443; 399, 416 (0.24), 440,
0.06
469
394, 415 (0.009), 443; 398, 416 (0.27), 440,
0.06
469
394, 417 (0.01), 441;
0.08
398, 417 (0.31), 441,
469
351 (0.81), 370 (1.04), 390 (1.04)
1 f 253 (12.4), 258 (14.7), 296 (1.16), 309 (3.08), 313 (3.23),
334 (0.96), 352 (1.19), 371 (1.19), 390 (1.16)
1g 251 (13.6), 258 (15.8), 281 (3.4), 301 (1.99), 316 (3.30),
332 (3.79), 352 (1.20), 370 (1.37), 390 (1.33)
2b 237 (2.49), 248 (1.58), 256 (1.62), 261 (1.74), 272 (2.33),
283 (2.41), 293 (1.39), 299 (0.64)
447 (<0.1)
486 (<0.1)
582 (0.23)
444, 469 (0.20)
500 (0.41)
395, 417 (0.012), 441; 394 , 416 (0.35), 442,
0.09 469
394, 428 (0.008), 442; 399, 416 (0.52), 441,
0.07
470
566, 610 (0.38)
421 (0.14), 448; 0.02
443 (1.2), 486
2c 231 (1.89), 243 (1.65), 253 (1.48), 266 (1.41), 290 (2.76),
305 (3.60), 326 (0.36), 350 (0.24)
non-emissive
593 (0.31)
479 (0.27), 487, 522, 462 (0.16), 490; 0.03
562
457 (1.5), 467, 502, 543
499 (2.5), 530
2d 233 (3.17), 256 (2.07), 278 (3.74), 284 (4.37), 290 (4.96),
297 (5.38), 306 (5.23), 320 (2.98), 327 (1.16)
2e 235 (4.93), 240 (5.46), 253 (3.69), 266 (3.32), 274 (2.55),
297 (2.44), 311 (2.96), 335 (0.39), 352 (0.26)
2 f 235 (2.96), 258 (3.78), 263 (3.51), 275 (2.15), 280 (1.79),
287 (1.17), 315 (1.69), 332 (1.61), 380 (2.23)
3a 239 (1.77), 328 (4.36), 375 (0.43), 399 (0.093)
3b 238 (6.32), 254 (6.69), 287 (2.62), 300 (2.15), 327 (0.94),
331 (0.56)
514 (0.89), 548, 596
527 (0.26), 570, 627
488 (0.51), 565
497 (0.10), 531; 0.05
non-emissive
462 (0.18), 524
362 (0.12); 0.04
490 (3.1), 501, 529,
545, 570
412 (2.3), 422, 530,
542,
533 (19.8)
490, 537 (1.43), 571
366, 378, 386 (0.10);
0.03
non-emissive
619 (0.19)
610 (24.5)
535, 576, 627 (0.38)
non-emissive
335, 345 (0.06), 362;
0.059
3c 227 (2.59), 255 (sh, 3.56), 262 (4.62), 275 (3.72), 296 (0.37) 429, 460 (0.42), 446 (12.8)
437 (0.14); 0.023
416, 441 (max, 47.9)
489 (3.18)
488
3d 244 (7.35), 287 (5.36), 297 (4.74), 309 (5.38), 380 (6.78),
499 (0.54)
511 (0.97)
446 (0.36); 0.32
404 (6.49)
3e 228 (2.02), 258 (sh, 3.03), 266 (3.47), 274 (5.03), 286 (4.55), 451, 485 (5.32), 481 (max, 35.7), 505 452, 480 (0.19); 0.053 457 (74.5), 491
306 (0.49)
515
(sh)
3 f 225 (1.48), 267 (4.19), 280 (3.77), 288 (sh, 1.93)
non-emissive
472 (0.24)
404, 426 (0.02); 0.018 456 (0.51), 488
[a] Measured in CH2Cl2 solution at 298 K (concentration ca. 1ꢁ10ꢀ5 moldmꢀ3), lex =243 nm for 1b–1g; lex =239 nm for 2b–2 f; lex =256 nm for 3b; lex
=
274 nm for 3c and 3e; lex =300 nm for 3d; lex =267 nm for 3 f. [b] lex =350 nm; lifetimes of solid 1b–1g at 298 K are less than 0.1 ms. [c] At 77 K, solvent
for 1b–1g and 2b–2 f: 2-MeTHF; 3a-3 f: CH2Cl2 (concentration ca. 1ꢁ10ꢀ5 moldmꢀ3).
CH2Cl2 display peak maxima at 230–380 nm (Table 1 and
Figure S2 in the Supporting Information), and a similar ab-
sorption profile can be found for the absorption bands of
1b–1c and 1e–1g at 290–340 nm. These bands are tentative-
ly assigned to acetylide-based p–p* transitions.
The gold(I) bis-isocyanide complexes 3b–3 f display in-
tense absorption bands with peak maxima in the 230–
290 nm spectral region which are assigned to p–p* transi-
tions of arylisocyanide ligands (Figure 1b and Figure S3 in
the Supporting Information). Complex 3d displays p–p*
transitions localized at the pyrene ring. Complex 3b displays
Complexes 1b, 1d, 2d, and 3a have been studied for sol-
vent effect on absorption spectrum (Figure 2, Figures S4–S6
in the Supporting Information). In CH3CN, 1b displays a
new peak at 292 nm which is not present in other solvents.
2d displays a blue-shift in absorption maximum when the
solvent is changed from CH2Cl2 to CH3CN, CH3OH, and
THF (Figure S6 in the Supporting Information), similarly to
that observed for 1b and 1d. The absorption profile of 3a
and its corresponding free isocyanide P3 are similar (Fig-
ure S7 in the Supporting Information, CH2Cl2: 287 nm;
CH3CN: 226, 231, and 285 nm; CH3OH: 225, 232, and
286 nm; THF: 281 nm) with 3a showing a significant batho-
chromic shift in absorption. This is attributed to the coordi-
nation of the P3 to gold(I) which allows the ligand-based
LUMO to be lowered in energy with the n(lone pair on ni-
low energy absorption bands at 300, 327, and 331 nm (emax
~
21500, 9400, and 5620 dm3 molꢀ1 cmꢀ1). All of these absorp-
tion bands are assigned to a mixture of naphthalene-based
p–p* transitions and metal-to-ligand charge transfer with
reference to previous spectroscopic works on related gold(I)
complexes.[35–36] The molecular structures of 3c and 3e are
similar but the absorption spectrum of 3e is bathochromical-
ly shifted from that of 3c (Figure 1b). This is attributed to
the presence of the electron-rich para-substituted ethynyl
group.
trogen)!p*
ACHTUNGTREN(NGNU aryl) intra-ligand charge transfer transition red-
shifted in energy (Figure 2 and Figure S7 in the Supporting
Information). As depicted in Figure 2, 3a in CH2Cl2 displays
a characteristic absorption peak at 328 nm, where a similar
absorption maximum can also be located for the complex in
CH3OH (326 nm), THF (327 nm), and DMF (330 nm).
546
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Chem. Asian J. 2011, 6, 544 – 553

Gold(I) Complexes Containing Carbon-Donor Ligands
tion band at 288 nm in DMSO. We suggest that the unusual
hypsochromic shifts of complex 3a in coordinating solvents,
such as acetonitrile and DMSO, is likely as a result of the
formation of a trigonally coordinated gold(I) geometry in
the excited state.
Luminescent Properties
[Au
G
G
CH2Cl2 solutions (Figure 3) and in the solid state (Figure S8
in the Supporting Information). In the cases of complexes
Figure 3. Emission spectra of P1, [Au
(CꢁCAr)] (1b–1g) in degassed CH2Cl2 at 298 K (concentration: 1ꢁ
10ꢀ5 moldmꢀ3).
(NHC1)Cl] (1a) and [Au(NHC1)-
ACHUTGTNRENNUG ACHTUNGTRENNUNG
AHCTUNGTRENNUNG
Figure 1. Top: UV/Vis absorption of ligand P1, [Au
[Au
(NHC1)
(CꢁCAr)] (1b and 1d) in CH2Cl2 solution at 298 K. Bottom:
(NHC1)Cl] (1a) and
ACHTUNGTRENNUNG
1b–1g, their emission spectra in degassed CH2Cl2 solutions
are similar to the emission profile of the free ligand P1, with
the emission energies of the former to have emission life-
times in nanosecond regime. Therefore, we assign the emit-
G
ACHTUNGTRENNUNG
UV/Vis absorption spectra of [AuACHTNUGTRENNUNG
solution at 298 K (concentration: 1ꢁ10ꢀ5 moldmꢀ3).
1
ting excited states of complexes 1b–1g to be p–p* excited
states localized at the NHC ligand. Although Lin[37] and co-
3
workers suggested the occurrence of p–p* emission of the
acetylide in gold(I) complexes bearing both benzimidazol-2-
ylidene and phenylacetylide ligands, the emission spectra of
1b–1g in solutions are reminiscent to that of anthracene
fluorescence with emission lifetimes all in the nanosecond
time regime (Table 1). Complex 2a [Au
emissive in the solid state and in solutions at room tempera-
ture and 77 K. In the series of complexes [Au
(NHC2)-
(CꢁCAr)] (2b–2 f), only 2b, 2d, and 2 f are emissive in the
solid state at room temperature. 2b–2 f ([Au
(NHC2)-
(NHC2)Cl] is non-
ACHTUNGTRENNUNG
ACHTUNGTRENNUNG
AHCTUNGTRENNUNG
ACHTUNGTRENNUNG
N
ture and the emissions are attributed to p–p* excited states
of the arylacetylide ligand with lifetimes in the microsecond
time regime (Table 1). This is consistent with Linꢂs explana-
tion previously reported.[37]
Figure 2. UV/Vis absorption spectra of complex 3a [Au(CꢁN-2,6-
Me2C6H4-4-NMe2)2]+ in various solvents at 298 K (concentration: 1ꢁ
10ꢀ5 moldmꢀ3).
Except 3a and 3 f, all of the [Au
ACHTUNGTRENNUNG
are luminescent in the solid state at room temperature
(Figure 4). In the solid state, 3c–3e display a strong blue
emission which could be visualized under UV irradiation.
At room temperature, the solid-state emission spectrum of
3c shows an intense peak maximum at 460 nm with weaker
However, 3a displays a solvatochromic shift in absorption
maximum (286 nm) in CH3CN; although 3a possesses a sim-
ilar absorption profile in both CH2Cl2 and DMSO (absorp-
tion maximum in DMSO: 331 nm), there is an extra absorp-
Chem. Asian J. 2011, 6, 544 – 553
ꢀ 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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547

W. Lu, C.-M. Che et al.
FULL PAPERS
Figure 5. Normalized emission spectra of complex 3a [Au(CꢁN-2,6-
Me2C6H4-4-NMe2)2]+ in solid state and in glassy solution at 77 K.
362 nm with vibrational spacings of ca. 1250–1300 cmꢀ1.
These emission peak maxima are assigned to naphthalene-
localized p–p* excited states.
X-ray Crystallography
Crystals of [Au
tained by slow diffusion of n-hexane/n-pentane into CH2Cl2/
CHCl3 solutions; while crystals of [Au
A
N
AHCTUNGTRENNUNG
were obtained by slow diffusion of n-hexane into CHCl3.
Crystal data and details of data collection and refinement
are summarized in Tables S2 and S3 in the Supporting Infor-
mation with the perspective view of the crystals depicted in
Figure 6, Figures S13, S15, and S16 in the Supporting Infor-
mation. Selected bond distances (ꢃ) and bond angles (8) of
the crystals are summarized in Table S4 in the Supporting
Information.
Figure 4. Top: Normalized solid-state emission spectra of 3b–3e at room
temperature (lem =350 nm). Bottom: Normalized emission spectra of 3b–
3 f in CH2Cl2 solutions at 298 K (concentration: 1ꢁ10ꢀ5 moldmꢀ3).
shoulders at 429 nm and 488 nm; while 3e has a strong emis-
sion peak maximum at 485 nm with shoulder peaks at
451 nm and 519 nm. It is of interest to note that all of these
emission peaks come from the 2,6-diisopropylphenyl group.
Unexpectedly, 3b in the solid state displays a red emission
at 619 nm (Figure 4a) with a lifetime of 0.19 ms.[38]
All five crystal structures of [Au
(NHC)
E
linear coordination geometry around the gold(I) cation:
1b C(1)-Au(1)-C(9)=175.2(2)8; 1c C(24)-Au(1)-C(1)=
179.47(19)8; 1d C(1)-Au(1)-C(13)=177.4(3)8; 1e C(1)-
Au(1)-C(15)=177.21(15)8; and 2d C(1)-Au(1)-C(12)=
ꢀ
The solid-state emission spectra of all of the gold(I) aryli-
socyanide complexes show a bathochromic shift compared
to that of the corresponding solution emission spectra
(Figure 4). We attribute this observation to intermolecular
Au···Au and p–p interactions in the solid state. The emission
lifetimes for all of the gold(I) arylisocyanide complexes re-
ported here are in the microsecond time regime, supporting
the phosphorescent nature of the emission. Complex 3a is
non-emissive at room temperature in both solid and de-
gassed solutions, but 3a is strongly emissive with a peak
maximum at 533 nm in CH2Cl2 at 77 K (Figure 5). We pro-
pose the emission of 3a is temperature-dependent owing to
3a favoring strong intermolecular interactions in its solid
state at 77 K, with its solid (610 nm) emission exhibiting a
significant bathochromic shift when compared with its emis-
sion in solution (533 nm) at 77 K. Complex 3b exhibits an
emission in degassed CH2Cl2 that is completely different
from its solid-state emission at room temperature (Figure 4),
the latter emission shows peak maxima at 335, 345, and
175.0(3)8. The Au(1) CACTHNUGRTENUNG(carbene) distances of 1b–1e and 2d
are 2.017(6) ꢃ, 2.019(4) ꢃ, 2.001(8) ꢃ, 2.026(4) ꢃ, and
2.011(7) ꢃ, respectively, which are comparable to that re-
ported[39–40] for [Au(NHC)2]+ and [Au
ACTHUNTGRNENUG ACHTUNTGERN(NUGN NHC)Cl]. The aver-
ꢀ
ꢀ
age of Ccarbene N(1) and Ccarbene N(2) distances are
1.358(7) ꢃ, 1.358(6) ꢃ, 1.362(4) ꢃ, 1.355(1) ꢃ, and
1.350(1) ꢃ for complexes 1b–1e and 2d, respectively, these
data are comparable to those found in other AuI NHC com-
plexes.[41] Complex 3a [Au(CꢁN-2,6-Me2C6H4-4-NMe2)2]+
has a linear coordination defined by the bond angle
175.0(3)8 along C(1)-Au(1)-C(12). The bond distances fall
within normal ranges and selected bond distances and
angles are listed in Table S4 in the Supporting Information.
No intermolecular aurophilic interactions can be found in
ꢀ
the crystal structure. The two Au Cisocyanide bonds are
ꢀ
ꢀ
1.972(8) ꢃ (Au(1) C(1)) and 1.991(8) ꢃ (Au(1) C(12)), re-
spectively, which are comparable to related literature
values.[42–46] The two C ꢁN distances are 1.383(8) ꢃ and
548
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ꢀ 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Asian J. 2011, 6, 544 – 553

Gold(I) Complexes Containing Carbon-Donor Ligands
Complex 3a [Au(CꢁN-2,6-
Me2C6H4-4-NMe2)2]+
has
a
linear coordination defined by
the bond angle 175.0(3)8 along
C(1)-Au(1)-C(12). The bond
distances fall within normal
ranges and selected bond dis-
tances and angles are listed in
Table S4 in the Supporting In-
formation. No intermolecular
aurophilic interactions can be
ꢀ
found. The two Au Cisocyanide
bond lengths are 1.972(8) ꢃ
ꢀ
(Au(1) C(1)) and 1.991(8) ꢃ
ꢀ
(Au(1) C(12)), which are com-
parable to related literature
values.[42–46] The two C ꢁN dis-
tances are 1.383(8) ꢃ and
1.365(9) ꢃ, respectively, which
are slightly shorter than that of
the free isocyanide ligands re-
ported previously[42–46] (such as
2,6-dimethylphenylisocyanide
with a CꢁN bond length of
1.399(2) ꢃ). The slight shorten-
ing in CꢁN distance upon
complexation to gold(I) arises
from the inductive effect of the
cationic AuI. Free isocyanide
coordinating to electrophilic
metal ions always leads to an
increase in the infrared CꢁN
stretching frequency.[42–46]
No intermolecular AuI···AuI
interactions can be found in the
crystal structures of [Au
ACHTUNGTRENNUNG(NHC)-
AHCTUNGTRENNUNG
ture of 1b, there are intermo-
lecular p–p interactions be-
tween adjacent anthracene
rings with a distance of 3.436 ꢃ
(Figure S12 in the Supporting
Information). The crystal struc-
ture of 1d reveals intermolecu-
ꢀ
lar interactions of C H
tyl)···C(anthracene),
ACHTUNGTRENNUNG(n-bu-
Figure 6. Perspective view of 1b (top), 1d (middle), and 3a (bottom) with thermal ellipsoids in 40% probabili-
ty. Hydrogen atoms have been omitted for clarity.
ꢀ
C
H(methylene)···C(anthracene),
and p–p between two anthra-
1.365(9) ꢃ, respectively, which are slightly shorter than
those of the free isocyanide ligands reported previously[42–46]
(such as 2,6-dimethylphenylisocyanide with a CꢁN bond
length of 1.399(2) ꢃ). The slight shortening in CꢁN dis-
tance upon complexation to gold(I) is a result of the induc-
tive effect of the cationic AuI. Thus, free isocyanide coordi-
nating to an electrophilic metal ion always leads to an in-
crease in the infrared CꢁN stretching frequency with a
shorter bond distance.[42–46]
cene rings (Figure S14 in the Supporting Information). Al-
though no aurophilic and p–p interactions can be found in
3a [Au
ACHTUNGTRENNUNG
teractions between a gold(I) ion and the aryl ring of the iso-
cyanide ligand of the neighboring cation with distances of
about 3.45 ꢃ (Figure 7). Such a feature may contribute to
the driving force for self-aggregation between cationic AuI
species leading to the formation of organogold(I)-based
nanowires.
Chem. Asian J. 2011, 6, 544 – 553
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www.chemasianj.org
549

W. Lu, C.-M. Che et al.
FULL PAPERS
tending over 2.8 mm were found. We have attempted to use
other solvent systems such as CH3CN/H2O, CH2Cl2/Et2O,
and CHCl3/Et2O (all are in 1:9 v/v ratio), but no nanowires
were observed. Selected area electron diffraction (SAED)
pattern (Figure 8d) recorded with a single nanowire of com-
plex 1d revealed a d-spacing of 15.38 ꢃ in the direction per-
pendicular to the nanowire long axis and that the nanowires
grew along the b-axis. The nanowires of complex 1b re-
vealed a d-spacing of 11.47 ꢃ perpendicular to the nanowire
long axis and the nanowires grew likely along the crystal b-
axis. We suggest that the p–p interactions between anthra-
cene rings play a role to direct the anisotropic growth of the
nanostructures (Figures S12 in the Supporting Information).
The molecular packing of complex 1b reveals intermolecu-
lar p–p interactions between anthracene rings with distances
of 3.44 ꢃ (Figure S12 in the Supporting Information); while
ꢀ
Figure 7. Molecular packing diagram of cation 3a reveals the existence of
intermolecular gold(I)···p interactions between cationic gold(I) center
and the aromatic ring of the isocyanide over 3.47–3.58 ꢃ, such pattern is
repeatable between a pair of 3a cations along the b-axis.
for complex 1d, both C HACTHUNGTRENNG(U n-butyl)···C(anthracene), C-
H(methylene)···C(anthracene), and p···p interactions be-
tween anthracene rings are observed (Figure S14 in the Sup-
porting Information). These intermolecular interactions con-
tribute to the anisotropic self-aggregation of the neutral or-
ganogold(I) complexes leading to the formation of nano-
wires.
Molecular Aggregation
Self-assembly of organometallic or organic molecules is a
useful method to fabricate supramolecular functional mate-
rials. In this regard, non-covalent intermolecular interactions
provide driving forces to construct molecular assemblies
with micro and nano sized structures having extensive hy-
drogen bonding, p–p, and van der Waals interactions.[47–55]
A reprecipitation method was adopted to prepare the mo-
lecular aggregates of the gold(I) complexes with N-heterocy-
clic carbene and arylacetylide ligands. THF solutions of
complexes 1b and 1d at a concentration of 400 mm were pre-
pared. The stock solutions were diluted to 40 mm with H2O
to give dispersions in THF/H2O (1:9 v/v). These dispersions
were sonicated and stored at room temperature. Complexes
1b and 1d were found to form nanowires in the freshly pre-
pared dispersions. Transmission electron microscopy (TEM)
images of dispersion of complex 1b (Figure 8a) in THF/
H2O revealed nanowires with uniform diameters of 120 nm
and length extending over 5.6 mm. For complex 1d (Fig-
ure 8c), nanowires with diameters of 44 nm and length ex-
Among the six [AuCAHTUNGTRENNUNG
only 3a and 3e were found to form well-defined nanostruc-
tures. The nanostructures of 3a and 3e were prepared as
those of 1b and 1d. Transmission electron microscopy
(TEM) images of a THF/H2O dispersion of complex 3a
(Figure 9a) with a concentration of 40 mm revealed the for-
mation of nanowires with uniform diameter ~30 nm and
length extending over 800 nm. Similarly for the dispersion
of complex 1b, nanobelts of 3e (Figure 9c) with a typical di-
ameter of 150 nm and length extending over 2.5 mm were
found. Attempts were made to use other solvent systems to
prepare organogold(I) nanowires such as CH3CN/H2O,
CH2Cl2/Et2O, and CHCl3/Et2O (all are in a 1:9 v/v ratio),
but no nanowires could be detected.
Complex 3a formed nanowires with much smaller diame-
ters than those obtained from complex 3e under the same
Figure 8. TEM images and the corresponding single nanowire SAED pat-
terns of complexes 1b (a and b) and 1d (c and d) freshly dipsersed in
THF/H2O (1:9, v/v) with a concentration of 40 mm.
Figure 9. TEM images the corresponding single nanowire SAED patterns
of complexes 3a (a and b) and TEM images of 3e (c and d) freshly dip-
sersed in THF/H2O (1:9 v/v) with a concentration of 40 mm.
550
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Chem. Asian J. 2011, 6, 544 – 553

Gold(I) Complexes Containing Carbon-Donor Ligands
lamp stability. Sample and standard solutions were degassed with at least
three freeze-pump-thaw cycles. The emission quantum yield was mea-
sured with quinine sulfate in degassed 0.1m sulfuric acid as reference The
conditions. Electron diffraction rings in the selected area
electron diffraction (SAED) pattern (Figure 9b) of complex
3a revealed a d-spacing of 11.3 ꢃ, and the nanowires likely
grew along the b-axis. The crystal structure of complex 3a
reveals that there are intermolecular gold(I)···p interactions
between the gold(I) center and the aromatic ring of the iso-
cyanide ligand at 3.45 ꢃ. Such interactions are repeatable
between two cations of 3a along the b-axis. This structural
feature could contribute to directing the anisotropic growth
nanostructures and self-aggregation between the cationic
gold(I) species by intermolecular gold(I)···p interactions to
give organogold(I)-based nanowires. Nanowires of complex
3e should be formed by such directional intermolecular in-
teractions.
emission lifetime measurements were performed on
a gated single-
photon counting system equipped with a Quanta Ray DCR-3 pulsed
Nd:YAG laser (pulse output 266 nm; 10 ns) and multichannel scaler
SR430. Errors for l values (ꢂ1 nm), t (ꢂ10%), and F (ꢂ10%) are esti-
mated. Crystals of suitable size were mounted either on glass fibres or in
capillary tubes. Diffraction experiments were performed at 301 K on a
Rigaku AFC7R diffractometer with graphite-monochromatized Mo-Ka
radiation (l=0.71073 ꢃ) using w–2q scans. Data collection was made
with 28 oscillation step of f, 10 min exposure time, and scanner distance
at 120 mm. The images were interpreted and intensities integrated using
the DENZO program.[57] The structures of complexes 1b–1e, 2d, and 3a
were solved by direct methods employing the SIR-97 program[57] on a
PC. The heavy atoms (Au) in complexes 1b–1e, 2d, and 3a were located
according to the direct methods and the successive least-square Fourier
cycles. Positions of other non-hydrogen atoms were found after successful
refinement by full-matrix least-squares using the SHELXL-97 pro-
gram.[41] The unweighted and weighted agreement factor (R, Rw) and the
goodness-of fit (GoF) are calculated by:
Conclusions
R1 ¼ jjFojꢀjFcjj=jFoj,
A series of gold(I) complexes bearing N-heterocyclic car-
bene (NHC), acetylide, and isocyanide ligands were pre-
2
2
2
2 2
Rw ¼ f½wðFo ꢀFc Þ ꢃ=½wðFo Þ ꢃg1=2, and
pared and formulated as [Au
ACHTUNGTRENNUNG
G
G
2
2
2
1=2
GoF ¼ S ¼ f½wðFo ꢀFc Þ ꢃ=ðnꢀpÞg
,
thracene ring (complexes 1b–1g) show anthracene-type fluo-
rescence emission which are proved by the short lifetimes in
the nanosecond regime. Most bis(arylisocyanide)gold(I)
complexes are emissive in both solid and fluid states at
298 K. The molecular aggregation of complexes 1b and 1d
were examined and these complexes were found to form
nanowires in mixtures of THF/H2O. Nanowires of com-
plexes 3a and nanobelts of 3e were attributed to the inter-
where n is the number of reflections and p is the total number of parame-
2
ters refined. The weighting scheme is: w=1/[s CAHTUNGTRENNNUG
2
is [2Fc2+Max
ACHTUNGTRENNUNG
CCDC 780909 (1d), CCDC 780914 (1e), CCDC 780912 (2d) and
CCDC 780910 (3a) contain the supplementary crystallographic data for
this paper. These data can be obtained free of charge from The Cam-
bridge Crystallographic Data Centre at www.ccdc.cam.ac.uk/data_
request/cif.
ꢀ
molecular hydrogen-bonding between the C H bond of the
Synthesis and characterization of organogold(I) nanostructures of 1b, 1d,
3a and 3e: THF solutions of complexes 1b/1d/3a/3e at a concentration
of 400 mm were prepared. The stock solutions were diluted to 40 mm with
H2O to give dispersions in THF/H2O (1:9 v/v). These dispersions were so-
nicated for 15 min and left at room temeprature. Several drops of the
nanowire dispersion were deposited on a carbon-coated copper grid and
the excess solvent was removed by a piece of filter paper. The TEM
(transmission electron spectroscopy) and SAED (selected area electron
diffraction) images were recorded on a Philips Tecnai 20 electron micro-
scope (accelerating voltage of 200 kV).
iso-propyl group on the isocyanide ligand and the F atom on
the trifluoromethanesulfonate anion. This work demon-
strates that luminescent organogold(I) complexes with
carbon-donor ligands could be useful molecular building
blocks for assembly of nanostructured organometallic mate-
rials.
Synthesis of precursor ligands P1–P8: The synthetic procedures of N-(n)-
butyl-N’-9-anthraceneyl-methylene-imidazolium chloride (P1) and N,N’-
diethylimidazolium iodide (P2) can be found in the Supporting Informa-
tion. The free arylisocyanides 2-isocyanonaphthalene (P4), 2,6-diisoprop-
yl-4-bromophenylisocyanide (P5), and 4-methoxyphenylisocyanide (P8)
were synthesized according to the published procedure,[58] while the syn-
thetic procedures of 2,6-dimethyl-4-dimethylaminophenylisocyanide (P3),
1-(4-isocyano-3,5-diisopropyl-phenylethynyl)-pyrene (P6), and 5-ethynyl-
2-isocyano-1,3-diisopropyl-benzene (P7) are recorded in the Supporting
Information.
Experimental Section
Chemicals: All starting materials were used as received from commercial
sources. KAuCl4 was purchased from Oxkem Limited. The precursor for
synthesis, [AuACHTUNGTRENNUNG(tht)Cl], was prepared according to the literature
method.[56] Acetonitrile and dichloromethane used in the reaction was
distilled over calcium hydride. All other solvents were of analytical
grade. Solvents used in emission data collection were of HPLC grade.
Instrumentation: Fast-atom-bombardment (FAB) mass spectra were ob-
tained on a Finnigan Mat 95 mass spectrometer. 1H (400 MHz) and 13C
(126 MHz) NMR spectra were obtained on DPX 400 and 126 MHz
Bruker FT-NMR spectrometers with chemical shifts (in ppm) relative to
tetramethylsilane. Elemental analysis was performed at the Institute of
Chemistry at the Chinese Academy of Science, Beijing. UV/Vis spectra
were recorded on a Perkin–Elmer Lambda 19 UV/Vis spectrophotome-
ter. Steady-state emission spectra were recorded on a SPEX 1681 Fluoro-
log-2 series F111A1 spectrophotometer. Low temperature (77 K) emis-
sion spectra for glassy solutions and solid-state samples were recorded in
5 mm diameter quartz tubes which were placed in a liquid nitrogen
Dewar equipped with quartz windows. The emission spectra were cor-
rected for monochromator and photomultiplier efficiency and for xenon
Synthesis of [Au
G
G
ture of Ag2O and P1 or P2 (in 1:1.7 molar ratio) in CH2Cl2 (30 mL) was
stirred for 20 h. It was then filtered using a cannula into another reaction
flask which contained AuACTHNUGRTNEUNG(tht)Cl (1.7 molar eq.). The reaction mixture
was stirred for another 20 h and then filtered using a cannula into anoth-
er reaction flask which contained ArCꢁCH (ꢄ1.7 molar eq.) and NaOH
(ꢄ1.7 molar eq.) in 10 mL CH3CN, and stirred for 20 h. The solvent was
evaporated and a black solid was formed. CHCl3 (30 mL) was added, the
insoluble black impurities were filtered out and discarded, a clear filtrate
was collected and was concentrated to about 6 mL. Excess cool Et2O was
added and the pure solid was crystallized out. The product was filtered
and washed with cool Et2O and dried under vaccum. The detailed charac-
Chem. Asian J. 2011, 6, 544 – 553
ꢀ 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemasianj.org
551

W. Lu, C.-M. Che et al.
FULL PAPERS
terization data of all [Au
Supporting Information.
G
G
f) S. J. Shieh, X. Hong, S. M. Peng, C. M. Che, J. Chem. Soc. Dalton
Trans. 1994, 3067–3068; g) V. W. W. Yam, S. W. K. Choi, J. Chem.
Soc. Dalton Trans. 1996, 4227–4232; h) V. W. W. Yam, S. W. K.
Choi, K. K. Cheung, Organometallics 1996, 15, 1734–1739; i) W. J.
Hunks, M. A. MacDonald, M. C. Jennings, R. J. Puddephatt, Orga-
nometallics 2000, 19, 5063–5070; j) C. M. Che, H. Y. Chao, V. M.
Miskowski, Y. Li, K. K. Cheung, J. Am. Chem. Soc. 2001, 123, 4985–
4991; k) W. Lu, H. F. Xiang, N. Zhu, C. M. Che, Organometallics
2002, 21, 2343–2346; l) W. Lu, N. Zhu, C. M. Che, J. Am. Chem.
Soc. 2003, 125, 16081–16088; m) F. Mohr, E. Cerrada, M. Laguna,
Organometallics 2006, 25, 644–648; n) J. C. Y. Lin, R. T. W. Huang,
C. S. Lee, A. Bhattacharyya, W. S. Hwang, I. J. B. Lin, Chem. Rev.
2009, 109, 3561–3598 and reference therein; o) V. W. W. Yam,
J. K. W. Lee, C. C. Ko, N. Y. Zhu, J. Am. Chem. Soc. 2009, 131, 912–
913; p) E. Vergara, E. Cerrada, A. Casini, O. Zava, M. Laguna, P. J.
Dyson, Organometallics 2010, 29, 2596–2603.
Synthesis of [Au
N
N
ACHTUNGTRENNUNG
1.0 molar eq. of free arylisocyanide (P3–P8) were dissolved in 25 mL
CH2Cl2. A clear solution was formed and was stirred overnight. After
24 h, another 1 molar eq. of arylisocyanide, excess LiOSO2CF3, and 5 mL
CH3CN were added as a clear solution. The mixture was stirred for an-
other 24 h. The solvent was evaporated. The solid was washed with Et2O
to wash away the excess LiOTf. A pure solid was formed. The detailed
characterization data of all [Au
in the Supporting Information.
G
ACHTUNGTNER(NUNG OTf) complexes can be found
Acknowledgements
[21] C. Heinemann, T. Muller, Y. Apeloig, H. Schwarz, J. Am. Chem.
Soc. 1996, 118, 2023–2038.
[22] C. Boehme, G. Frenking, J. Am. Chem. Soc. 1996, 118, 2039–2046.
[23] A. J. Arduengo, III, S. F. Gamper, J. C. Calabrese, F. Davidson, J.
Am. Chem. Soc. 1994, 116, 4391–4394.
[24] W. A. Herrmann, G. Gerstberger, M. Spiegler, Organometallics
1997, 16, 2209–2212.
[25] W. A. Herrmann, K. ꢅfele, M. Elisin, F. E. Kꢆhn, P. W. Roesky, J.
Organomet. Chem. 1994, 480, c7–c9.
This work was supported by the ꢄNanotechnology Research Programꢂ of
the University Development Fund of The University of Hong Kong, the
Hong Kong Research Grants Council (HKU 7008/09P), and the Area of
Excellence Scheme established under the University Grants Committee
of the Hong Kong SAR, China (AoE/P-03/08). A.L.F.C. is grateful for a
postgraduate studentship from The University of Hong Kong. W.L.
thanks The University of Hong Kong for a Research Assistant Professor-
ship and the seed funding.
[26] W. A. Herrmann, G. M. Lobmaier, M. Elison, J. Organomet. Chem.
1996, 520, 231–234.
[27] H. M. J. Wang, C. S. Vasam, T. Y. R. Tsai, S. H. Chen, A. H. H.
Chang, I. J. B. Lin, Organometallics 2005, 24, 486–493.
[28] D. V. Partyka, A. J. Esswein, M. Zeller, A. D. Hunter, T. G. Gray,
Organometallics 2007, 26, 3279–3282.
[29] V. Sharma, D. Piwnica-Worms, Chem. Rev. 1999, 99, 2545–2560.
[30] R. E. Robinson, T. C. Holovics, S. F. Deplazes, G .H. Lushington,
D. R. Powell, M. V. Barybin, J. Am. Chem. Soc. 2003, 125, 4432–
4433.
[31] A. Mayr, J. Guo, Inorg. Chem. 1999, 38, 921–928.
[32] D. Philp, J. F. Stoddart, Angew. Chem. 1996, 108, 1242–1286;
Angew. Chem. Int. Ed. Engl. 1996, 35, 1154–1196.
[33] M. J. Irwin, J. J. Vittal, R. J. Puddephatt, Organometallics 1997, 16,
3541–3547.
[1] C.-H. Lai, I.-C. Wu, C.-C. Kang, J.-F. Lee, M. L. Ho, Chem.
Commun. 2009, 1996–1998.
[2] Y. Xia, P. Yang, Y. Sun, Y. Wu, B. Mayers, B. Gates, Y. Yin, F. Kim,
Y. Yan, Adv. Mater. 2003, 15, 353–389.
[3] J. Chen, B. Wiley, Y. Xia, Langmuir 2007, 23, 4120–4129.
[4] Z. Liu, P. C. Searson, J. Phys. Chem. B 2006, 110, 4318–4322.
[5] Q.-Q. Wang, J.-B. Han, D.-L. Guo, S. Xiao, Y.-B. Han, H. M. Gong,
X. W. Zou, Nano Lett. 2007, 7, 723–728.
[6] U. Yogeswaran, S. M. Chen, Sensors 2008, B130, 739–749.
[7] C. Yu, J. Irudayaraj, Anal. Chem. 2007, 79, 572–579.
[8] H. Ding, K. T. Yong, I. Roy, H. E. Pudavar, W. C. Law, E. J. Bergey,
P. N. Prasad, J. Phys. Chem. C 2007, 111, 12552–12257.
[9] A. K. Oyelere, P. C. Chen, X. Huang, I. H. El-Sayed, M. A. El-
Sayed, Bioconjugate Chem. 2007, 18, 1490–1497.
[10] J. Huang, R. Fan, S. Connor, P. Yang, Angew. Chem. 2007, 119,
2466–2469; Angew. Chem. Int. Ed. 2007, 46, 2414–2417.
[11] B. L. Prasad, C. M. Sorensen, K. J. Klabunde, Chem. Soc. Rev. 2008,
37, 1871–1883.
[34] M.-A. MacDonald, R. J. Puddephatt, Organometallics 2000, 19,
2194–2199.
[35] W. A. Herrmann, M. Elisin, J. Fischer, C. Kçcher, G. R. J. Artus,
Angew. Chem. 1995, 107, 2602–2605; Angew. Chem. Int. Ed. Engl.
1995, 34, 2371–2374.
[36] A. Altomare, M. C. Burla, M. Camalli, G. Cascarano, C. Giacovaz-
zo, A. Guagliardi, A. G. G. Moliterni, G. Polidori, R. Spagna, J.
Appl. Crystallogr. 1999, 32, 115–119.
[12] T. Wang, X. Hu, J. Wang, S. Dong, Talanta 2008, 75, 455–460.
[13] J. A. A. W. Elemans, R. de Gelder, A. E. Rowan, R. J. M. Nolte,
Chem. Commun. 1998, 1553–1554.
[37] H. M. J. Wang, C. Y. L. Chen, I. J. B. Lin, Organometallics 1999, 18,
1216–1223.
[14] M. Enomoto, A. Kishimura, T. Aida, J. Am. Chem. Soc. 2001, 123,
5608–5609.
[38] M. Stender, R. L. White-Morris, M. M. Olmstead, A. L. Balch,
Inorg. Chem. 2003, 42, 4504–4506.
[39] Z. Wang, C. J. Medforth, J. A. Shelnutt, J. Am. Chem. Soc. 2004,
126, 15954–15955.
[15] L. Valade, H. Casellas, S. Roques, C. Faulmann, D. de Caro, A.
Zweik, L. Aries, J. Solid State Chem. 2002, 168, 438–443.
[16] J.-J. Chiu, C.-C. Kei, T.-P. Perng, W.-S. Wang, Adv. Mater. 2003, 15,
1361–1364.
[40] M. Morikawa, M. Yoshihara, T. Endo, N. Kimizuka, J. Am. Chem.
Soc. 2005, 127, 1358–1359.
[41] J. F. Britten, C. J. L. Lock, Z. Wang, Acta Crystallogr. Sect. C 1992,
48, 1600–1603.
[17] H. Liu, Q. Zhao, Y. Li, Y. Liu, F. Lu, J. Zhuang, S. Wang, L. Jiang,
D. Zhu, D. Yu, L. Chi, J. Am. Chem. Soc. 2005, 127, 1120–1121.
[18] Y. Sun, K. Ye, H. Zhang, J. Zhang, L. Zhao, B. Li, G. Yang, B. Yang,
Y. Wang, S.-W. Lai, C.-M. Che, Angew. Chem. 2006, 118, 5738–
5741; Angew. Chem. Int. Ed. 2006, 45, 5610–5613.
[42] H. G. Raubenheimer, P. J. Olivier, L. Lindeque, M. Desmet, J.
ˇ
Hrusak, G. J. Kruger, J. Organomet. Chem. 1997, 544, 91–100.
[19] a) W. Lu, V. A. L. Roy, C.-M. Che, Chem. Commun. 2006, 3972–
3974; b) W. Lu, S. S.-Y. Chui, K.-M. Ng, C.-M. Che, Angew. Chem.
2008, 120, 4644–4648; Angew. Chem. Int. Ed. 2008, 47, 4568–4572.
[20] For examples, see: a) M. I. Bruce, E. Horn, J. G. Matisons, M. R.
Snow, Aust. J. Chem. 1984, 37, 1163–1170; b) R. J. Cross, M. F. Da-
vidson, J. Chem. Soc. Dalton Trans. 1986, 411–414; c) D. Li, X.
Hong, C. M. Che, W. C. Lo, S. M. Peng, J. Chem. Soc. Dalton Trans.
1993, 2929–2932; d) G. Jia, R. J. Puddephatt, J. D. Scott, J. J. Vittal,
Organometallics 1993, 12, 3565–3574; e) G. Jia, N. C. Payne, J. J.
Vittal, R. J. Puddephatt, Organometallics 1993, 12, 4771–4778;
[43] M. V. Baker, P. J. Barnard, S. J. Berners-Price, S. K. Brayshaw, J. L.
Hickey, B. W. Skelton, A. H. White, J. Organomet. Chem. 2005, 690,
5625–5635.
[44] C. Nieto-Oberhuber, S. Lçpez, A. M. Echavarren, J. Am. Chem.
Soc. 2005, 127, 6178–6179.
[45] M. V. Baker, P. J. Barnard, S. K. Brayshaw, J. L. Hickey, B. W. Skel-
ton, A. H. White, Dalton Trans. 2005, 37–43.
[46] S. Singh, S. S. Kumar, V. Jancik, H. W. Roesky, H. G. Schmidt, M.
Noltemeyer, Eur. J. Inorg. Chem. 2005, 3057–3062.
552
www.chemasianj.org
ꢀ 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Asian J. 2011, 6, 544 – 553

Gold(I) Complexes Containing Carbon-Donor Ligands
[47] J. Arias, M. Bardaji, P. Espinet, Inorg. Chem. 2008, 47, 3559–3567.
[48] S. Coco, C. Cordovilla, C. Domꢇnguez, P. Espinet, J. Chem. Soc.
Dalton Trans. 2008, 6894–6900.
[49] J. H. Paek, K. H. Song, I. Jung, S. O. Kang, J. Ko, Inorg. Chem. 2007,
46, 2787–2796.
[50] J. Arias, M. Bardaji, P. Espinet, Inorg. Chem. 2008, 47, 1597–1606.
[51] J. Vicente, J. Gil-Rubio, N. Barquero, P. G. Jones, D. Bautista, Orga-
nometallics 2008, 27, 646–659.
[52] P. Rçmbke, A. Schier, H. Schmidbaur, J. Chem. Soc. Dalton Trans.
2001, 2482–2486.
[54] H. Ecken, M. M. Olmstead, B. C. Noll, S. Attar, B. Schlyer, A. L.
Balch, J. Chem. Soc. Dalton Trans. 1998, 3715–3720.
[55] U. Siemeling, D. Rother, C. Bruhn, Organometallics 2008, 27, 6419–
6426.
[56] R. Uson, A. Laguna, M. Laguna, Inorg. Synth. 1989, 26, 85–91.
[57] G. M. Sheldrick, 1997. SHELXS-97. Programs for Crystal Structure
Analysis (Release 97–2): University of Goetingen, Germany.
[58] I. Ugi, U. Fetzer, U. Eholzer, H. Knupfer, K. Offermann, Angew.
Chem. 1965, 77, 492–504; Angew. Chem. Int. Ed. Engl. 1965, 4,
472–484.
[53] T. J. Mathieson, A. G. Langdon, N. B. Milestone, B. K. Nicholson, J.
Chem. Soc. Dalton Trans. 1999, 201–208.
Received: July 18, 2010
Published online: September 13, 2010
Chem. Asian J. 2011, 6, 544 – 553
ꢀ 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemasianj.org
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