Syntheses, Spectroscopic, Electrochemical, and Third-Order Nonlinear Optical Studies of a Hybrid Tris{ruthenium(alkynyl)/(2-phenylpyridine)}iridium Complex

Article abstract of DOI:10.1002/chem.201500951

The synthesis of fac-[Ir{N,C₁′-(2,2′-NC₅H₄C₆H₃-5′-ξC-1-C₆H₂-3,5-Et₂-4-ξCC₆H₄-4-ξCH)}₃] (10), which bears pendant ethynyl groups, and its reaction with [RuCl(dppe)₂]PF₆ to afford the heterobimetallic complex fac-[Ir{N,C₁′-(2,2′-NC₅H₄C₆H₃-5′-ξC-1-C₆H₂-3,5-Et₂-4-ξCC₆H₄-4-ξC-trans-[RuCl(dppe)₂])}₃] (11) is described. Complex 10 is available from the two-step formation of iodo-functionalized fac-tris[2-(4-iodophenyl)pyridine]iridium(III) (6), followed by ligand-centered palladium-catalyzed coupling and desilylation reactions. Structural studies of tetrakis[2-(4-iodophenyl)pyridine-N,C₁′](μ-dichloro)diiridium 5, 6, fac-[Ir{N,C₁′-(2,2′-NC₅H₄C₆H₃-5′-ξC-1-C₆H₂-3,5-Et₂-4-ξCH)}₃] (8), and 10 confirm ligand-centered derivatization of the tris(2-phenylpyridine)iridium unit. Electrochemical studies reveal two (5) or one (6-10) Ir-centered oxidations for which the potential is sensitive to functionalization at the phenylpyridine groups but relatively insensitive to more remote derivatization. Compound 11 undergoes sequential Ru-centered and Ir-centered oxidation, with the potential of the latter significantly more positive than that of Ir(N,C′-NC₅H₄-2-C₆H₄-2)₃. Ligand-centered π-π transitions characteristic of the Ir(N,C′-NC₅H₄-2-C₆H₄-2)₃ unit red-shift and gain in intensity following the iodo and alkynyl incorporation. Spectroelectrochemical studies of 6, 7, 9, and 11 reveal the appearance in each case of new low-energy LMCT bands following formal Ir^III/IV oxidation preceded, in the case of 11, by the appearance of a low-energy LMCT band associated with the formal Ru^II/III oxidation process. Emission maxima of 6-10 reveal a red-shift upon alkynyl group introduction and arylalkynyl π-system lengthening; this process is quenched upon incorporation of the ligated ruthenium moiety on proceeding to 11. Third-order nonlinear optical studies of 11 were undertaken at the benchmark wavelengths of 800 nm (fs pulses) and 532 nm (ns pulses), the results from the former suggesting a dominant contribution from two-photon absorption, and results from the latter being consistent with primarily excited-state absorption.

Full text of DOI:10.1002/chem.201500951

DOI: 10.1002/chem.201500951
Full Paper
&
Heterometallic Complexes
Syntheses, Spectroscopic, Electrochemical, and Third-Order
Nonlinear Optical Studies of a Hybrid Tris{ruthenium(alkynyl)/
(2-phenylpyridine)}iridium Complex**
Huajian Zhao,[a, b] Peter V. Simpson,[a] Adam Barlow,[a] Graeme J. Moxey,[a]
Mahbod Morshedi,[a] Nivya Roy,[c] Reji Philip,[c] Chi Zhang,[a, b] Marie P. Cifuentes,[a] and
Mark G. Humphrey*[a]
Abstract: The synthesis of fac-[Ir{N,C1’-(2,2’-NC5H4C6H3-5’-Cꢀ positive than that of Ir(N,C’-NC5H4-2-C6H4-2)3. Ligand-cen-
C-1-C6H2-3,5-Et2-4-CꢀCC6H4-4-CꢀCH)}3] (10), which bears
pendant ethynyl groups, and its reaction with [RuCl(dp-
pe)2]PF6 to afford the heterobimetallic complex fac-[Ir{N,C1’-
(2,2’-NC5H4C6H3-5’-CꢀC-1-C6H2-3,5-Et2-4-CꢀCC6H4-4-CꢀC-trans-
[RuCl(dppe)2])}3] (11) is described. Complex 10 is available
from the two-step formation of iodo-functionalized fac-
tris[2-(4-iodophenyl)pyridine]iridium(III) (6), followed by
ligand-centered palladium-catalyzed coupling and desilyla-
tion reactions. Structural studies of tetrakis[2-(4-iodophenyl)-
pyridine-N,C1’](m-dichloro)diiridium 5, 6, fac-[Ir{N,C1’-(2,2’-
NC5H4C6H3-5’-CꢀC-1-C6H2-3,5-Et2-4-CꢀCH)}3] (8), and 10 con-
firm ligand-centered derivatization of the tris(2-phenylpyridi-
ne)iridium unit. Electrochemical studies reveal two (5) or one
(6–10) Ir-centered oxidations for which the potential is sensi-
tive to functionalization at the phenylpyridine groups but
relatively insensitive to more remote derivatization. Com-
pound 11 undergoes sequential Ru-centered and Ir-centered
oxidation, with the potential of the latter significantly more
tered p–p* transitions characteristic of the Ir(N,C’-NC5H4-2-
C6H4-2)3 unit red-shift and gain in intensity following the
iodo and alkynyl incorporation. Spectroelectrochemical stud-
ies of 6, 7, 9, and 11 reveal the appearance in each case of
new low-energy LMCT bands following formal IrIII/IV oxidation
preceded, in the case of 11, by the appearance of a low-
energy LMCT band associated with the formal RuII/III oxida-
tion process. Emission maxima of 6–10 reveal a red-shift
upon alkynyl group introduction and arylalkynyl p-system
lengthening; this process is quenched upon incorporation of
the ligated ruthenium moiety on proceeding to 11. Third-
order nonlinear optical studies of 11 were undertaken at the
benchmark wavelengths of 800 nm (fs pulses) and 532 nm
(ns pulses), the results from the former suggesting a domi-
nant contribution from two-photon absorption, and results
from the latter being consistent with primarily excited-state
absorption.
Introduction
Because of their electronic, optical, magnetic, and catalytic
properties, transition metals are attractive components of func-
tional molecular materials. The construction of hybrid species
incorporating more than one type of ligated metal unit, each
of which introduces a distinct property, is therefore a particular-
ly appealing and rational approach to assemble multifunctional
materials.
[a] H. Zhao, Dr. P. V. Simpson, A. Barlow, Dr. G. J. Moxey, Dr. M. Morshedi,
Prof. C. Zhang, Dr. M. P. Cifuentes, Prof. M. G. Humphrey
Research School of Chemistry
Australian National University
Canberra, ACT 2601 (Australia)
Fax: (+61)2-6125-0750
Amongst the panoply of possible functional ligated metal
units, complexes based on the tris(2-phenylpyridine)iridium
motif have attracted considerable interest due to potential ap-
plications as electrophosphorescent materials (e.g., inorganic
light-emitting diodes (PHOLEDs) for large screen displays).[1]
However, hybridization of tris(2-phenylpyridine)iridium with
other functional metal-ligand moieties is little explored, one
notable exception being its recent coupling with electro-active
ferrocenyl units.[2]
E-mail: mark.humphrey@anu.edu.au
[b] H. Zhao, Prof. C. Zhang
School of Chemical Engineering
Nanjing University of Science and Technology
Nanjing 210094 (P.R. China)
[c] N. Roy, Prof. R. Philip
Raman Research Institute
C. V. Raman Avenue, Sadashivanagar
Bangalore 560080 (India)
[**] Part 53: Organometallic Complexes for Nonlinear Optics
Ruthenium alkynyl complexes comprise an important class
of organometallic complex that has been shown to exhibit
Supporting information for this article is available on the WWW under
http://dx.doi.org/10.1002/chem.201500951.
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redox and protically-switchable optical nonlinearity,[3] but their
hybridization with other functional metal-containing units is
also underexploited.[4] We report herein the synthesis of
a hybrid complex comprising a tris(2-phenylpyridine)iridium
core linked by aryleneethynylene bridges to peripheral trans-
[bis{bis(diphenylphosphino)ethane}chlororuthenium moieties,
together with initial studies of its electrochemical, linear opti-
cal, and nonlinear optical (NLO) properties.
lane afforded 4-trimethylsilylethynyl-2,6-diethylaniline (1) in ex-
cellent yield. Diazotization of the amino functionality and sub-
sequent iodination gave 4-trimethysilylethynyl-2,6-diethyl-1-io-
dobenzene (2) in good yield. A second Sonogashira coupling
was then utilized to afford 4-trimethylsilylethynyl-2,6-diethyl-1-
triisopropylsilylethynylbenzene (3) in excellent yield. Selective
desilylation at the more reactive trimethylsilyl site by carbon-
ate in methanol gave 4-ethynyl-2,6-diethyl-1-triisopropylsilyle-
thynylbenzene (4) in excellent yield. The mass spectra of 1–4
1
all contain strong molecular ions, while the H NMR spectrum
Results and Discussion
of the terminal acetylene 4 contains a characteristic CꢀCH res-
onance at 3.10 ppm; in addition, the structure of 2 was con-
firmed by a single-crystal X-ray diffraction study (Figure S1).
We have previously reported several examples of the assembly
of three ligated ruthenium alkynyl units about a central arene
group or nitrogen atom core, in
species with an idealized octu-
polar composition.[5] These com-
plexes possess interesting NLO
properties, so an analogous
composition, but with a tris(2-
phenylpyridine)iridium core, was
targeted in the current studies.
The bulky 1,2-bis(diphenylphos-
phino)ethane (dppe) and bis(di-
phenylphosphino)methane
(dppm) ligands that stabilize the
ruthenium environment towards
chloro(alkynyl) and bis(alkynyl) Scheme 1. Syntheses of 1–4. TMS=SiMe3, TIPS=SiiPr3.
complex formation[6] render
the trans-Ru(dppe)2 and trans-
Ru(dppm)2 moieties sterically demanding, a particular concern
when the goal is to assemble three such units around a core.
Molecular modelling studies suggested that accommodating
three such trans-Ru(dppe)2 groups about a tris(2-phenylpyridi-
ne)iridium core would necessitate incorporation of a di(1,4-
phenyleneethynylene) (2PE) “spacer” unit on each ruthenium-
containing arm, while prior experience with oligo(1,4-phenyle-
neethynylene) (OPE)-containing complexes suggested that
these 2PE units would require solubilizing substituents. Argua-
bly the easiest solubilizing groups to install are alkoxy groups,
but the use of alkyl groups is preferable in instances where the
optical properties are the primary focus. We have previously
explored the use of the 2,5-diethoxy-1,4-phenyleneethynylene
group as a solubilizing unit in OPE bridges in donor–p-bridge-
acceptor constructs in which the donor is a trans-Ru(dppe)2
moiety,[7] and the use of 2,5-dihexyloxy-1,4-phenyleneethyny-
lene solubilizing groups in OPE units (up to 9PE in length)
bridging two trans-Ru(dppe)2 units;[8] while syntheses to install
such groups are straightforward, the 2,5-dialkoxy-1,4-phenyl-
ene groups proved optically non-innocent in both cases. More
recently, we have replaced the 2,5-dialkoxy-1,4-phenylene
groups with 2,6-diethyl-1,4-phenylene units, linear optical stud-
ies revealing that replacing phenylene by a dialkylarylene
bridging unit leaves the UV/Vis/NIR spectrum essentially invari-
ant.[9] In the present work, we have therefore extended our use
of the 2,6-diethyl-1,4-phenylene bridging group as an optical-
ly-innocent solubilizing unit (Scheme 1). Thus, Sonogashira
coupling of 2,6-diethyl-4-iodoaniline with ethynyltrimethylsi-
The synthesis of complex 11, which incorporates three trans-
Ru(dppe)2 units disposed about a tris(2-phenylpyridine)iridium
core, is summarized in Scheme 2. Reaction of 2-(4-iodophenyl)-
pyridine and iridium trichloride trihydrate in hot ethoxyethanol
overnight gave the chloro-bridged species 5 in excellent yield.
Halide abstraction from 5 with silver triflate in the presence of
additional 2-(4-iodophenyl)pyridine proceeded to afford 6 in
good yield. The iodo functionality in 6 can undergo Sonoga-
shira coupling, PdII/CuI-catalyzed coupling with 4 giving 7 in
good yield. The triisopropylsilyl group in 7 was smoothly desi-
lylated by NaOH/methanol to afford 8, the pendant terminal
ethynyl group of the latter undergoing Sonogashira coupling
with 1-iodo-4-(trimethylsilylethynyl)benzene to give 9 and
a subsequent desilylation to afford 10. Reaction of 10 with
excess of the five-coordinate complex [RuCl(dppe)2]PF6 then af-
forded the target complex 11. Complexes 5–11 were character-
1
ized by IR spectroscopy (7–11), UV/Vis spectroscopy, H NMR
spectroscopy (Figure S2, S3, S5, S7, S9, S11, S13), 13C NMR spec-
troscopy (6–11: Figure S4, S6, S8, S10, S12, S14), 31P NMR spec-
troscopy (11), electrospray ionization mass spectrometry,
single-crystal X-ray diffraction studies (5, 6, 8, and 10), and sat-
isfactory microanalyses.
The synthesis of 5 followed the well-established procedure
for the syntheses of functionalized tetrakis[2-(phenyl)pyridine-
N,C1’](m-dichloro)diiridium complexes,[10] and afforded a product
with the same stereochemical outcome (mutually trans N and
mutually cis C atoms of the bidentate cyclometallated phenyl-
pyridine ligands: Figure 1). Bond lengths and angles exhibited
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Scheme 2. Syntheses of 5–11. TMS=SiMe3, TIPS=SiiPr3. C^N indicates an identical bidentate C,N-ligated 2-phenylpyridyl ligand to that depicted for each
complex.
by 5 (Figure S15, Table S1) are typical for complexes of this
general composition.[11] Complex 6 is formally the 4-iodo-func-
tionalized derivative of fac-tris(2-phenylpyridine)iridium(III),[12]
a well-known electroluminescent material that exhibits green
phosphorescent emission, and for which
a considerable
number of analogues have been explored. Functionalized fac-
tris(2-phenylpyridine)iridium(III) complexes have been prepared
by several general procedures, for example, heating tris(acety-
lacetonato)iridium(III) with excess of the cyclometallating
ligand in glycerol,[13] abstraction of chloride from dichloro-
bridged dimers,[14] and reaction of the dichloro-bridged dimers
with excess cyclometallating ligand and base in glycerol at
2008C.[15] In the present work, the synthesis of 6 proceeded in
good yield exploiting a modification of the halide abstraction
protocol. The subsequent series of reactions to afford 10 dem-
onstrate that functionalized fac-tris(2-phenylpyridine)iridium(III)
is a suitable platform for Pd-catalyzed CÀC coupling. Of partic-
ular interest, the formation of 7, and thereby the introduction
of six ethyl groups to the iridium complex, results in a concomi-
tant significant increase in solubility, an outcome that is possi-
bly of broader interest in the area of processable electrolumi-
nescent materials.
Figure 1. Molecular structure of tetrakis[2-(4-iodophenyl)pyridine-N,C1’](m-di-
chloro)diiridium 5, with thermal ellipsoids set at the 40% probability level.
Hydrogen atoms have been omitted for clarity. The asymmetric unit contains
two molecules of 5; one has been omitted from Figure 1 for clarity (see Fig-
ure S2). Selected bond lengths: Ir1ÀC11 2.5312(16), Ir1ÀC12 2.5586(15), Ir2À
C11 2.5112(15), Ir2ÀC12 2.5703(16), Ir1ÀN101 2.037(4), Ir1ÀN201 2.033(4),
Ir1ÀC111 2.001(5), Ir1ÀC211 1.996(5), Ir2ÀN301 2.049(4), Ir2ÀN401 2.048(4),
Ir2ÀC311 1.979(5), Ir2ÀC411 1.986(5) Š.
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Single-crystal X-ray structural studies confirmed the molecu-
lar composition of 6, 8, and 10; thermal ellipsoid plots are
given in Figures 2 (6), 3 (8), and 4 (10), while selected bond
lengths and angles are collected in Table 1. The effect of pe-
ripheral modification [proceeding from 5-iodo (6) to 5-(4’-eth-
ynyl-3’,5’-diethylphenyl)ethynyl (8) and then 5-{(4“-ethynyl-
phenyl)-4’-ethynyl-3’,5’-diethylphenyl}ethynyl (10)] on the key
complex structural parameters is relatively subtle (Table 1): all
sets of bond lengths C(x11)–Ir(1), N(x01)–Ir(1) and angles
C(x11)-Ir(1)-N(x01) (x=1, 2, 3) are equivalent within the 3s con-
fidence limit, consistent with the presence of rigid and not-
easily-deformable five-membered rings resulting from 2-phe-
nylpyridine ligation, the only significant differences in structur-
al data being the inter-ligand angles C(x11)-Ir(1)-C(y11), C(x11)-
Ir(1)-N(y01), and N(x01)-Ir(1)-N(y01) (x, y=1, 2, 3, x¼ y). Com-
plex 6 has a fac disposition of the three 2-(4-iodophenyl)pyri-
dine ligands, an arrangement that is maintained on subse-
quent functionalization to afford 8 and 10, and by implication
7, 9, and 11. Conversion from the kinetically favoured mer
form in such complexes to the thermodynamically favoured
fac isomer is photochemically and thermally promoted, so the
fac arrangement is by far the most common structurally-con-
firmed arrangement for three 2-arylpyridine ligands about an
iridium core,[11a,16] although crystallographically-verified exam-
ples with mer-stereochemistry are extant.[15,17]
Figure 3. Molecular structure of fac-[Ir{N,C1’-(2,2’-NC5H4C6H3-5’-CꢀC-1-C6H2-
3,5-Et2-4-CꢀCH)}3] (8), with thermal ellipsoids set at the 40% probability
level. Hydrogen atoms have been omitted for clarity.
Figure 4. Molecular structure of fac-[Ir{N,C1’-(2,2’-NC5H4C6H3-5’-CꢀC-1-C6H2-
3,5-Et2-4-CꢀCC6H4-4-CꢀCH)}3] (10), with thermal ellipsoids set at the 40%
probability level. Hydrogen atoms have been omitted for clarity.
Figure 2. Molecular structure of fac-tris[2-(4-iodophenyl)pyridine]iridium 6,
with thermal ellipsoids set at the 40% probability level. Hydrogen atoms
have been omitted for clarity.
um-centered oxidation process which is similar to that ob-
served for the non-functionalized [Ir(N,C’-NC5H4-2-C6H4-2)3]
(13).[18] Complexes 6–11 are 0.1–0.2 V more difficult to oxidize
than 13, consistent with the expected effect of the introduc-
tion of electron-withdrawing iodo or arylalkynyl groups. The
effect on the iridium-centered oxidation potential of modifying
the organic arylalkynyl group in proceeding from 7 to 8, 9,
and then 10 (desilylation, p-system lengthening, and then a fur-
ther desilylation) is negligible. The hybrid complex 11 also dis-
plays a reversible ruthenium-centered oxidation process at
0.61 V, corresponding to a slightly higher potential than that
seen for the analogous processes in the non-functionalized
trans-[Ru(CꢀCPh)Cl(dppe)2] (14) and trans-[Ru(CꢀCC6H4-4-Cꢀ
CPh)Cl(dppe)2] (15) (0.55 V).[19]
The electrochemical behaviour of both tris(2-phenylpyridi-
ne)iridium[18] and trans-bis(bidentate diphosphine)ruthenium
alkynyl complexes[3] have attracted attention, so it was of inter-
est to examine 11 and its precursors by cyclic voltammetry to
assess the effect of hybrid complex formation. The oxidation
potentials of complexes 5–11 were measured at room temper-
ature (Figure S16–S22 and Table 2; note that no reduction pro-
cesses were observed within the accessible solvent window).
Complex 5 displays two reversible oxidation processes (Fig-
ure S16), as is also seen for its non-functionalized analogue
[Ir2(m-Cl)2(N,C’-NC5H4-2-C6H4-2)4] (12),[10] but complex 5 is about
0.2 V more difficult to oxidize than complex 12, consistent
with electron depletion at the metal center due to the intro-
duction of four somewhat electron-withdrawing iodo substitu-
ents. All monoiridium complexes 6–11 show a reversible iridi-
The evolution of the linear absorption behaviour as the fac-
tris(2-phenylpyridine)iridium(III) core is functionalized and then
complexed to three RuII centers is also of interest, so UV/Vis/
Chem. Eur. J. 2015, 21, 11843 – 11854
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Table 1. Selected bond lengths [Š] and angles [8] for 6, 8, and 10.
Table 3. Linear absorption data for complexes 5–15, 6+, 7+, 9+, 11+,
112+, 13+, 14+ and 15+.
6
8[b]
10[c]
Wavenumber [cmÀ1] (extinction coefficient)
Ref.
Ir1ÀC111
2.016(4)
2.020(3)
2.017(3)
2.137(3)
2.125(3)
2.129(3)
2.028(8)
2.009(9)
2.010(9)
2.136(7)
2.119(8)
2.145(6)
95.7(3)
94.4(3)
79.8(3)
171.7(3)
88.0(3)
94.0(3)
91.8(3)
79.1(3)
172.4(3)
172.2(3)
92.5(3)
79.1(3)
93.7(3)
95.3(3)
97.9(3)
2.023(5)
2.030(5)
2.026(5)
2.145(5)
2.131(5)
2.143(5)
95.5(2)
94.4(2)
79.3(2)
174.16(18)
90.8(2)
95.6(2)
90.3(2)
79.4(2)
172.06(19)
171.81(19)
88.9(2)
Ir1ÀC211
5
20500 (560), 22900 (5100), 24800 (7200), 26700 (10000, sh), this
28100 (14000, sh), 32800 (59000, sh), 36900 (85000), 41100 work
(62000, sh)
Ir1ÀC311
Ir1ÀN101
Ir1ÀN201
12
6
20700 (1100, sh), 23000 (4200), 25000 (6300), 28200 (11000, [10]
sh), 28200 (13000), 38500 (68000)
Ir1ÀN301
C111-Ir1-C211
C111-Ir1-C311
C111)-Ir1-N101
C111-Ir1-N201
C111-Ir1-N301
C211-Ir1-C311
C211-Ir1-N101
C211-Ir1-N201
C211-Ir1-N301
C311-Ir1-N101
C311-Ir1-N201
C311-Ir1-N301
N101-Ir1-N201
N101-Ir1-N301
N201-Ir1-N301
95.46(14)
95.95(14)
79.42(14)
172.42(12)
90.25(13)
96.44(13)
87.21(12)
79.38(13)
173.15(12)
174.39(12)
90.18(13)
79.17(13)
94.69(12)
97.58(11)
95.29(12)
20700 (940), 22300 (3300, sh), 22700 (4500, sh), 24700
(8800, sh), 27000 (17000), 34600 (73000), 40900 (54000)
10300 (2300), 16700 (4600), 29800 (33000, sh), 32500
(45000, sh), 35200 (52000), 41600 (46000)
21700 (6000), 24800 (25000), 28100 (102000), 29900
(131000), 34600 (70000), 40700 (61000)
this
work
this
work
this
work
this
6+
7
7+
8
16400 (4300), 26400 (94000, sh), 28500 (121000), 33000
(91000, sh), 40700 (69000)
work
21700 (6200), 25100 (25000), 26000 (27000), 28400 (97000), this
30300 (127000), 40800 (63000)
work
9
21700 (6800), 28500 (211000), 34400 (65000), 41300
this
79.0(2)
(91000)
work
this
work
this
work
this
work
this
97.80(18)
95.69(19)
94.59(18)
9+
10
11
8060 (320), 16300 (2500), 27200 (178000), 37800
(68000, sh)
21700 (7900), 28900 (205000), 34500 (64000), 41600
(98000)
24200 (186000), 28200 (172000), 30100 (176000), 40100
(238000)
11+ 10600 (81000), 14500 (12000), 18200 (33000, sh), 21100
(68000, sh), 27900 (183000), 31900 (61000, sh)
Table 2. Cyclic voltammetric data for complexes 5–15.[a]
work
this
112+ 10600 (86000), 14200 (14000), 18400 (52000), 19700
E0 IrIII/IV
DEp
ipc/ipa
E0 RuII/III
DEp
ipc/ipa
(58000), 20900 (57000), 22900 (87000, sh), 25400 (173000, work
sh), 26800 (180000), 36500 (21000)
5
12
6
7
8
1.29, 1.54
1.09, 1.35
1.04
0.93
0.95
0.92
0.94
0.99
0.81
0.07, 0.07
n.a.
1, 1
n.a.
1
1
1
1
1
1
n.a.
–
–
–
–
–
–
–
–
0.61
–
–
–
–
–
–
–
–
0.06
–
–
–
–
–
–
–
–
1
–
1
1
13
20800 (1800, sh), 22400 (3500, sh), 24700 (7900, sh), 26400 this
(12000), 35300 (45000), 41100 (43000)
13+ 11 800 (1900), 17000 (4000), 30200 (15000), 33600
work
this
0.07
0.08
0.07
0.08
0.07
0.07
n.a.
(20000, sh), 36800 (33000)
work
[19c]
14
31400 (23000), 38500 (50000)
9
14+ 12000 (10000), 17000 (1000), 27300 (7000), 29800 (13000), [19c]
10
11
13
14
15
35700 (52000), 36500 (53000), 37300 (53000)
15
25800 (36000), 37900 (45000, sh), 40200 (50000)
[19c]
[19c]
15+ 11 200 (20000), 15600 (5000), 21200 (15000, sh), 22200
(26000), 24000 (18000), 31100 (23000, sh), 33800 (39000,
sh), 35600 (54000), 36700 (55000), 37200 (54000)
–
–
–
–
0.55
0.55
0.07
0.06
–
[a] All E0 values in
V vs Ag/AgCl. Conditions: CH2Cl2 solvent, 0.1m
NnBu4PF6 supporting electrolyte, 208C, 1 mm disk Pt working electrode,
and Pt auxiliary electrode. Sweep rate 0.100 VsÀ1. DEp values in V. Under
our conditions, DEp =0.07 for the FcH/FcH+ couple.
these absorptions characteristic of a functionalized tris(2-phe-
nylpyridine)iridium(III), the ruthenium–iridium hybrid complex
11 also shows an intense band at 24200 cmÀ1, which (consis-
tent with previous reports) is attributed to a MLCT transition
that is localized at the ruthenium alkynyl unit.[19c]
1
NIR data were obtained for all new complexes (Figure S23);
band maxima are listed in Table 3, together with data for 12–
15. For the tris(2-phenylpyridine)iridium(III) derivatives 6–10,
the intense absorption bands centered at about 35000 cmÀ1
(6) or 26000–30000 (7–10) can be assigned as ligand-centered
(LC) spin-allowed p!p* in nature.[20] These bands undergo
a red shift in proceeding from iodo-functionalized 6 to ethyn-
yl-functionalized 7–10, and a gain in intensity in proceeding
from the complexes with the shorter alkynyl group (7/8) to
those with the longer alkynyl unit (9/10). The broad absorption
bands at lower energies with maxima at about 24000–
27000 cmÀ1 are typical of spin-allowed 1MLCT transitions[20]
and at even lower energies, the weaker bands which reach
into the visible region are assigned as formally forbidden
3MLCT transitions,[20] with the former undergoing an increase
in intensity in proceeding from 7/8 to 9/10. In addition to
The spectroelectrochemical behaviour of selected examples
was then explored. Complexes 5–11 are optically transparent
at frequencies <20000 cmÀ1. The electrochemical conversion
of the complexes 6, 7, and 9 to the oxidized species was moni-
tored in dichloromethane using an OTTLE cell at room temper-
ature. Electrochemical oxidation of 11 and 13 was carried out
with the same setup, but at 233 K. All oxidations were under-
taken using a potential about 0.1 V higher than their oxidation
potentials (see Table 2), ensuring complete conversion. This re-
sulted in the progressive replacement of spectral peaks of the
complexes in the resting state with those of the oxidized spe-
cies; except for that of complex dication 112+, which did not
show complete reversibility, all spectral progressions afforded
isosbestic points (Figure S24–S30). Complexes 6, 7, 9 and 13
Chem. Eur. J. 2015, 21, 11843 – 11854
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show similar changes in their electronic spectra upon oxida-
tion, with new bands appearing in a spectral region transpar-
ent for the parent complexes (Figure S24–S26 and S30). The
oxidation of complex 11 to 11+ and then 112+ was carried out
in a stepwise fashion, with each oxidation followed by a reduc-
tion to ensure proper evaluation of the reversibility of each
redox process. The first oxidation (11 to 11+) is attributed to
ruthenium-centered oxidation and is accompanied by the ap-
pearance of a low-lying LMCT band at 10600 cmÀ1, similar to
the related chloro mono-alkynyl complex cations 14+ and 15+
(Table 3). As mentioned above, the second oxidation explored
with 11 (11+ to 112+) was not fully reversible, and isosbestic
points were not obtained (Figure S28). This oxidation is attrib-
uted to iridium-centered oxidation (formally the IrIII/IV process),
with similar spectral features to the 7/7+ and 9/9+ progres-
sions. No significant changes are apparent in the LMCT band
corresponding to the ruthenium unit following oxidation from
11+ to 112+, which is consistent with little or no communica-
tion between the metal centers.
The cubic NLO properties of the new hybrid complex 11
were assayed in a preliminary fashion by employing the Z-scan
technique[23] at the benchmark wavelengths of 800 nm (with
100 femtosecond pulses: Figures 5 and 6) and 532 nm (using 5
ns laser pulses: Figures 7 and 8).
If a laser pulse is spatially and temporally Gaussian in the Z-
scan experiment, the input fluence can be obtained from the
expression Fin(z)=2E/pw2 for a given position z, and the input
The photoluminescence of complexes 6–10 was then inves-
tigated in solvents of varying polarities at room temperature
(Table 4). As expected, the emission peaks in the spectra of
these complexes increase in intensity following deoxygenation,
but the spectral profiles are unchanged. The emission maxima
wavelengths are independent of the specific solvent em-
ployed, consistent with the luminescence originating primarily
Figure 5. Open-aperture Z-scan trace for 11 for ultrafast excitation using
100 fs laser pulses at 800 nm.
3
from ligand-centered (p!p*) states. Progression from [Ir(N,C’-
NC5H4-2-C6H4-2)3] (13) (510 nm in chlorobenzene[18] and tolu-
ene[21]) to the iodo-functionalized 6 results in a 9 nm blue-shift
in emission maximum. Extension of the p-conjugation associat-
ed with the alkynyl functionality (proceeding from 6 to 7/8) re-
sults in a 55–56 nm red-shift in emission, with a further 12–
14 nm red-shift observed upon further p-system lengthening
(proceeding from 7/8 to 9/10); there is an additional 2–3 nm
red-shift in emission maximum seen upon proceeding from
the terminal alkynes 8/10 to the trialkylsilyl-appended internal
alkynes 7/9. In cyclometalated iridium complexes, the excita-
tion processes can be both ligand-centred and MLCT in na-
ture.[2,14,18,20,21b,22] The presence of vibrational structure in the
emission spectra of 6–10 (Figure S31–S36) indicates that the
relevant excited state in these complexes may possess signifi-
cant ligand-centered character, and likely resulting from mixing
the 3MLCT states with p!p* states as previously demonstrated
for 13.[14,20]
Figure 6. Optical limiting data for 11 calculated from the Z-scan data em-
ploying fs pulses. Circles are data points while solid curves are numerical fits
obtained using Equation 2.
Table 4. Maximum emission wavelength for compounds 6–10 and 13 in
various solvents at room temperature.
Emission maximum (Stokes shift) [nm]
Toluene
THF
CH2Cl2
Ref.
6
13
7
8
9
501 (201)
n.a.
556 (221)
553 (208)
569 (223)
567 (229)
502 (202)
n.a.
556 (229)
553 (207)
568 (240)
566 (226)
501 (201)
510
555 (225)
553 (225)
568 (232)
566 (220)
this work
[15]
this work
this work
this work
this work
Figure 7. Open-aperture Z-scan trace for 11 for nanosecond excitation using
5 ns laser pulses at 532 nm.
10
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with two-step excited-state absorption/two-photon absorption.
The nonlinearity is again described numerically by equations
1 and 2, except that in this case it is more appropriate to
regard beff as the effective excited-state absorption coefficient.
The best-fit values of Is and beff are 8.0”1014 WmÀ2 and 8.0”
10À11 mWÀ1, respectively.
For ultrafast excitation, the laser pulse duration is shorter
than typical molecular excited-state lifetimes (which are usually
of the order of picoseconds), and so there should be minimal
excited-state absorption; the nonlinearity therefore mostly
arises from two-photon absorption. With nanosecond excita-
tion, in contrast, the molecules will (on average) exist in the ex-
cited states much longer due to multiple excitations, thereby
enhancing excited-state absorption significantly. Even though
the relative optical intensity is 5”103 times lower, and the rela-
tive fluence is only 10 times higher for the nanosecond excita-
tion, the corresponding nonlinear absorption coefficient is four
orders of magnitude larger, which clearly indicates the impor-
tance of excited-state absorption in the nonlinearity exhibited
by this material.
Figure 8. Optical limiting data calculated from the Z-scan data employing ns
pulses. Circles are data points while solid curves are numerical fits obtained
using Equation 2.
intensity can be obtained from Iin(z)=Fin(z)/t, where E is the
laser pulse energy, w is the 1/e2 beam radius, and t is the 1/
e temporal half-width of the pulse.[24] The Z-scan data can
hence be re-plotted in the form of transmission versus input
intensity or input fluence, which can be numerically fitted to
the relevant nonlinear transmission equations to calculate the
nonlinearity parameters.
Conclusion
The present studies have afforded 11 as the first example of
a ruthenium alkynyl/tris(phenylpyridine)iridium heterobimetal-
lic complex, a hybrid species merging redox- and NLO-active
ruthenium-containing groups with the electrophosphorescent
For ultrafast excitation (100 fs pulses), we used pulse ener-
gies of 5 mJ, and the sample had a linear transmission of 84%
at the excitation wavelength of 800 nm. It was found that the
measured nonlinear transmission data fit to a model that in-
cludes saturable absorption and two-photon absorption/two-
step excited-state absorption. The corresponding nonlinear ab-
sorption coefficient is given by:
tris(phenylpyridine)iridium
unit.
Accommodating
three
bis(dppe)-ligated ruthenium moieties about a tris(phenylpyridi-
ne)iridium core necessitated the use of di(phenyleneethyny-
lene) arms bearing ethyl solubilizing substituents. In previous
studies, the ethynyl functionality has been introduced into the
ligand sphere at photo-active iridium(III) centers via the coordi-
nation of preformed ligands (e.g., reaction of tetrakis[2-(phe-
nyl)pyridine-N,C1’](m-dichloro)diiridium with 5-ethynyl-2,2’-bi-
pyridine);[25] the present procedure is complementary in that it
does not subject the ethynyl group to the harsh phenylpyri-
dine ligand coordination reaction conditions and therefore af-
fords additional synthetic flexibility. Complex 6 is the second
example of a tris-ethynyl-functionalized tris(phenylpyridine)iri-
dium complex: the complex fac-tris[2-(5-ethynylphenyl)pyridi-
ne]iridium(III) was synthesized by selective 5-iodination of the
phenyl rings in tris(phenylpyridine)iridium using iodine/iodo-
benzene diacetate, followed by trimethylsilylethynylation via
palladium-catalyzed Stille coupling with trimethyl(tributylstan-
nylethynyl)silane, and desilylation on reaction with TBAF.[27] The
present studies reveal that Sonogashira coupling at fac-tris[2-
(iodophenyl)pyridine]iridium(III) centers is also facile, extending
the previous Stille report to a heavier alkyne, as well as dem-
onstrating a high-yielding subsequent metalation. This previ-
ous study reported that the use of nickel and copper catalysts
result in decomposition of the functionalized tris(phenylpyridi-
ne)iridium precursor,[26] but the use of copper in the present
system did not prove problematic. In other related studies, the
pyridine rings in fac-tris(2-phenyl-4-methylpyridine)iridium
have been tris-4-ethenylated by Knoevenagel coupling with
formylferrocene (amongst other functional aldehydes) in the
a0
ꢀ ꢁ
aðIÞ ¼
þ beff I
I
Is
ð1Þ
1 þ
where I is the input intensity, Is is the saturation intensity, a0 is
the linear absorption coefficient of the sample, and beff is the
effective two-photon absorption coefficient. The correspond-
ing propagation equation is given by:
ꢅꢃ
ꢂ
ꢃ ꢄꢄ
ꢆ
dI
dz0
I
Is
¼ À a0 1 þ
þ beffI I
ð2Þ
in which z’ represents the propagation distance within the
sample, and which can be numerically solved to obtain the
best-fit values of beff and Is. Since the role of excited-state ab-
sorption is relatively minimal for ultrafast excitation, two-
photon absorption will be the major contributor to the ob-
served optical limiting in this regime. The Is and beff values are
1.5”1017 WmÀ2 and 5.0”10À15 mWÀ1, respectively.
For nanosecond excitation, we used pulse energies of 50 mJ;
the sample transmission was 72% at the excitation wavelength
of 532 nm. The corresponding Z-scan data was found to fit
well to a model in which saturable absorption occurs along
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presence of potassium tert-butoxide.[2] The present studies
therefore extend peripheral metalation to the orthometalated
phenyl rings in the coordinated phenylpyridine ligands, signifi-
cantly enhancing the potential diversity.
lowing compounds were synthesized by literature procedures: 2-
(4-iodophenyl)pyridine,[27] [(4-iodophenyl)ethynyl]trimethylsilane,[28]
2,6-diethyl-4-iodoaniline,[29] trans-[RuCl2(dppe)2].[30] All other re-
agents were used as received.
Methods and instrumentation: Microanalyses were carried out at
the Research School of Chemistry, Australian National University.
UV/Vis spectra were recorded in CH2Cl2 in 1 cm path length quartz
cells using a Cary5 spectrophotometer; bands are reported as
wavenumber (cmÀ1) [extinction coefficient (m<M->1 cm<M->1)]. Infra-
red spectra were recorded as KBr discs using a Perkin–Elmer
System 2000 FT-IR; peaks are reported in cmÀ1. ESI mass spectra
(both unit resolution and high resolution (HR)) were recorded
using a Bruker Apex 4.7T FTICR-MS at the Research School of
Chemistry, Australian National University. 1H (400 MHz), 13C
(101 MHz), and 31P NMR (162 MHz) spectra were recorded using
a Varian Gemini-400 FT NMR spectrometer and are referenced to
residual chloroform (7.26 ppm), CDCl3 (77.0 ppm), or external
H3PO4 (0.0 ppm), respectively. Assignments follow the numbering
scheme below. Cyclic voltammetry measurements were recorded
using an e-corder 401 potentiostat system from eDaq Pty Ltd.
The optical and electrochemical properties of the new
hybrid complex 11 and its precursors have been assayed and
compared to that of cognate species. Compared to 13, the po-
tentials for the iridium-centered oxidation process in 6–11 in-
crease as expected for introduction of electron-withdrawing
groups (iodo, arylalkynyl, and RuIII), the potential of the last-
mentioned being consistent with some “communication”
through the intermetallic p-delocalizable bridge; an analogous
electrochemical study was not undertaken with the aforemen-
tioned ferrocenyl hybrid,[2] so the present study establishes
modulation of iridium-centered properties in such complexes
by redox-control of a peripheral metal. The linear absorption
spectra of 6–11 retain the characteristics of that of the non-
functionalized “parent” complex 13, with the expected red-
shift in bands upon p-system lengthening, and ap-
pearance of a characteristic low-energy MLCT band
on incorporation of the bis(dppe)-ligated Ru moiety.
Spectroelectrochemical studies were not undertaken
for the ferrocenyl-containing hybrid complex;[2] for
the hybrid complex in the present study, the lack of
significant variation in the characteristic low-energy
LMCT band following oxidation from 11+ (formally
RuIIIIrII) to 112+ (RuIIIIrIII) is consistent with largely inde-
pendent or similarly coupled ligated iridium and
ruthenium units in 11+ and 112+. The luminescence
behaviour of 6–11 was assayed, the maximum in 13
red-shifting on proceeding to 7–10, and with the
bathochromic shift significant for p-system lengthen-
ing and much smaller for trialkylsilyl incorporation.
The hybrid complex 11 was non-emissive in CH2Cl2 at room
temperature. The aforementioned ferrocenyl hybrid was simi-
larly non-emissive at both room temperature and 77 K, with
the quenching suggested to derive from photo-induced elec-
tron transfer from the readily oxidizable ferrocenyl group,[2]
and the redox-active ligated ruthenium group in 11 is presum-
ably effecting the same outcome through a similar mechanism.
Finally, preliminary nonlinear optical studies of 11 are consis-
tent with its potential as an optical limiting material with
a broad temporal profile; the data are consistent with its be-
haviour as a two-photon absorber under femtosecond excita-
tion conditions and as an excited-state absorber under nano-
second excitation conditions.
Measurements were carried out at room temperature using 1 mm
Pt disc working-, Pt wire auxiliary-, and Ag/AgCl reference electro-
des, such that the ferrocene/ferrocenium redox couple was located
at 0.56 V (ipc/ipa =1, DEp 0.09 V). Scan rates were typically
100 mVsÀ1. Electrochemical solutions contained 0.1m (NnBu4)PF6
and ca. 10À3 m complex in dried and distilled dichloromethane. Sol-
utions were purged and maintained under a nitrogen atmosphere.
Solution spectra of the oxidized species were obtained at 298 K
except for 11 and 13 which were run at 233 K by electrogeneration
in an optically-transparent thin-layer electrochemical (OTTLE) cell
with potentials about 100 mV beyond E1/2 for each oxidation peak
(see Table 2), to ensure complete electrolysis; solutions were made
up in 0.1m (NnBu4)PF6 in dichloromethane. Fluorescence measure-
ments were obtained using a Varian Cary Eclipse Fluorescence
Spectrometer in three different solvents (see Table 4) at 208C, exci-
tation and emission slits 5, scan rate 600 nmminÀ1. The nonlinear
optical transmissions of CH2Cl2 solutions of 11 in a 1 mm cuvette
were measured by the open-aperture Z-scan technique with laser
pulses of 100 fs and 5 ns duration (FWHM) at 800 and 532 nm, re-
spectively. A convex lens of ca. 20 cm focal length was employed
to focus the beam.
Experimental Section
Materials: All reactions were performed under a nitrogen atmos-
phere with the use of Schlenk techniques unless otherwise stated.
Dichloromethane was dried by distilling over calcium hydride, di-
ethyl ether and tetrahydrofuran (THF) were dried by distilling over
sodium/benzophenone, and all other solvents were used as re-
ceived. “Petrol” refers to a fraction of boiling range 60–808C. Chro-
matography was on silica gel (230–400 mesh). Sodium hexafluoro-
phosphate was recrystallized from acetonitrile prior to use. The fol-
2,6-Diethyl-4-{(trimethylsilyl)ethynyl}aniline (1): 2,6-Diethyl-4-io-
doaniline (3.10 g, 11.3 mmol) was added to a deoxygenated mix-
ture of [PdCl2(PPh3)2] (20.0 mg, 1.37 mmol), CuI (19 mg, 0.50 mmol)
and triethylamine (50 mL). Trimethylsilylacetylene (1.6 mL,
11.4 mmol) was added, and the mixture was stirred at room tem-
perature for 12 h, filtered, and the filtrate added to ether, trans-
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ferred to a separatory funnel, and washed with an aqueous solu-
tion of NH4Cl and then brine. The solvent was removed from the
organic fraction under vacuum and the residue purified by silica
column chromatography, eluting with a mixture of n-hexane and
ethyl acetate (10:1). The solvent was removed from the eluate to
give a waxy brown solid, which was recrystallized from methanol
and water, giving 1 as an off-white solid (2.45 g, 88%). Rf (hexane/
iPr3SiCꢀC-1-C6H2-2,6-Et2-4-CꢀCH (4): This reaction was not con-
ducted under an inert atmosphere. Compound
3 (1.77 g,
4.30 mmol) followed by K2CO3 (0.7 g, 5.1 mmol) was added to
a mixture of CH2Cl2 and methanol (1:1, 30 mL), and the resultant
mixture stirred for 2 h. Water was added and the product extracted
with CH2Cl2, drying with Na2SO4. The solvent was removed under
reduced pressure to give 4 as a colorless liquid (1.26 g, 86%). Rf
(hexane) = 0.57; 1H NMR (400 MHz, CDCl3): d=7.19 (s, 2H, H15),
3.10 (s, 1H, ꢀCH), 2.81 (q, JHH =7.6 Hz, 4H, CH2), 1.25 (t, JHH =7.6 Hz,
6H, CH3), 1.15 ppm (s, 18H, SiiPr3); 13C{1H} NMR (101.5 MHz, CDCl3):
d=147.1 (C16), 129.1 (C15), 122.8 (C17), 121.5 (C14), 103.2 (C19), 100.8
(C18), 84.1 (C13), 77.9 (C12), 28.2 (CH2), 18.8 (CH3-SiiPr3), 14.9 (CH3),
11.5 ppm (CH); MS (EI+): m/z (%): 338.2 (40) [M]+, 295.2 (100)
[MÀiPr]+; HRMS (ESI+): calcd [C23H34Si] 338.2430; found: [M]+
338.2432.
1
EtOAc 10:1) = 0.15; H NMR (400 MHz, CDCl3): d=7.11 (s, 2H, H15),
3.79 (brs, 2H, NH2), 2.48 (q, JHH =7.6 Hz, 4H, CH2), 1.24 (t, JHH
=
7.6 Hz, 6H, CH3), 0.23 ppm (s, 6H, SiMe3); 13C{1H} NMR (101.5 MHz,
CDCl3): d=142.3 (C17), 129.9 (C15), 127.1 (C16), 111.9 (C14), 106.8 (C13),
90.7 (C12), 23.9 (CH2), 12.7 (CH3), 0.2 ppm (SiMe3); MS (EI+): m/z (%):
245.1 (92) [M]+, 230.1 (100) [MÀMe]+; HRMS (ESI+): calcd for
C15H23NSi 245.1603; found: [M]+ 245.1603; elemental analysis (%)
calcd for C15H23NSi: C 73.41, H 9.44, N 5.71; found: C, 73.42, H 9.65,
N 5.82.
Tetrakis[2-(4-iodophenyl)pyridine-N,C1’](m-dichloro)diiridium (5):
A mixture of 2-(4-iodophenyl)pyridine (700 mg, 2.49 mmol) and
IrCl3·3H2O (351 mg, 0.996 mmol) in ethoxyethanol/H2O (3:1, 15 mL)
was thoroughly deoxygenated by sparging with nitrogen for
15 min, and was then heated at 1308C overnight. H2O was added
and the resulting precipitate was collected and washed with H2O.
The solid was dissolved in CH2Cl2, washed with H2O (”2), dried
over MgSO4 and concentrated in vacuo, and added to Et2O, afford-
ing 5 as a yellow solid (660 mg, 84%). Single crystals of 5 suitable
for a single-crystal X-ray diffraction study were grown by slow dif-
fusion of hexane into a dichloromethane solution of 5 at room
4-Trimethysilylethynyl-2,6-diethyl-1-iodobenzene (2): Compound
1 (2.15 g, 10.7 mmol) was added to Et2O (60 mL) and the resultant
mixture was cooled to À208C in an acetone/dry ice bath. BF3·OEt2
(12 mL, 45.5 mmol, 50% solution in ether) was added to the mix-
ture dropwise over 30 min. tert-Butyl nitrite (4.4 mL, 34.1 mmol)
was then added and the mixture stirred at À208C for 30 min, and
then allowed to warm to 58C over 10 min. Cold Et2O (50 mL) was
added, affording a yellow precipitate after 20 min stirring. This was
collected by filtration and washed with cold ether, before being
added to MeCN (20 mL). A mixture of NaI (3.20 g, 21.6 mmol) and
I2 (0.2 g, 0.8 mmol) in MeCN (10 mL) was then added dropwise and
the resultant mixture stirred overnight. An aqueous solution of
Na2S2O3 was then added to the stirring mixture. The product was
extracted with ether and the organic layer dried with Na2SO4. The
solvent was removed and the residue purified by column chroma-
tography on silica, eluting with hexane. The solvent was removed
from the eluate under reduced pressure to give 2 as a colorless
solid (2.07 g, 64%). Single crystals of 2 suitable for a single-crystal
X-ray diffraction study were grown from an aqueous methanol so-
lution. Rf (hexane) = 0.64; 1H NMR (400 MHz, CDCl3): d=7.14 (s,
2H, H15), 2.77 (q, JHH =7.6 Hz, 4H, CH2), 1.21 (t, JHH =7.6 Hz, 6H,
CH3), 0.24 ppm (s, 6H, SiMe3); 13C{1H} NMR (101.5 MHz, CDCl3); d=
147.3 (C16), 129.0 (C15), 122.9 (C14), 107.9 (C17), 104.5 (C13), 94.7 (C12),
35.4 (CH2), 14.5 (CH3), 0.1 ppm (SiMe3); MS (EI+): m/z (%): 356.1 (60)
[M]+, 341.0 (100) [MÀMe]+; HRMS (ESI+): calcd [C15H21ISi] 356.0464;
found: 356.0464 [M]+; elemental analysis (%) calcd for C15H21ISi: C
50.56, H 5.94; found: C 50.89, H 6.08.
1
temperature. H NMR (400 MHz, CDCl3): d=9.10 (brd, J=6, 4H, H1),
7.88 (d, J=8, 4H, H4), 7.80 (m, 4H, H3), 7.24 (d, J=8, 4H, H7), 7.17
(dd, J=8, J=1.5, 4H, H8), 6.84 (ddd, J=7, J=6, J=1.5, 4H, H2),
6.18 ppm (d, 4H, H10, J=1.5). Due to low solubility, a 13C NMR spec-
trum was not acquired; HRMS (ESI+): m/z: calcd [C46H31ClI4Ir2N5]
1583.7676; found: 1583.7646 [MÀCl+MeCN]+; elemental analysis
(%) calcd for C44H28Cl2I4Ir2N4: C 33.54, H 1.79, N 3.56; found: C
33.67, H 1.69, N 3.37.
fac-Tris[2-(4-iodophenyl)pyridine]iridium(III) (6): Compound
5
(500 mg, 0.32 mmol) was added to a mixture of 2-(4-iodophenyl)-
pyridine (642 mg, 2.28 mmol) and AgOTf (203 mg, 0.80 mmol) in
diglyme (15 mL), and the mixture thoroughly deoxygenated and
then heated at 1308C overnight. Water (30 mL) was added, precipi-
tating a brown solid. The solid was collected, washed with Et2O (”
3) and then dissolved in thf and passed through Celite. The eluate
was reduced in volume and Et2O was added, precipitating a yellow
powder that was washed with Et2O (”3) and dried in vacuo, afford-
ing 6 as an analytically pure yellow solid (640 mg, 97%). Single
crystals of 6 suitable for an X-ray diffraction study were grown by
slow evaporation of an acetone solution of 6 at room temperature.
1H NMR (400 MHz, [D6]DMSO): d=8.22 (d, J=8, 3H, H4), 7.87 (m,
3H, H3), 7.65 (d, J=8, 3H, H7), 7.43 (brd, J=6, 3H, H1), 7.24 (dd, J=
8, 2, 3H, H8), 7.20 (m, 3H, H2), 6.90 ppm (d, J=2, 3H, H10); 13C{1H}
NMR (101 MHz, [D6]DMSO): d=164.3 (C5), 162.6 (C6), 147.0 (C1),
143.7 (C10), 137.6 (C3), 128.9 (C8), 126.5 (C7), 123.7 (C2), 119.7 (C4),
99.2 ppm (C9); HRMS (ESI+): m/z: calcd [C33H21I3IrN3Na] 1055.8397;
found [M+Na]+ 1055.8398 ; elemental analysis (%) calcd for
C33H21I3IrN3: C 38.39, H 2.05, N 4.07; found: C 38.48, H 2.28, N 3.85.
iPr3SiCꢀC-1-C6H2-2,6-Et2-4-CꢀCSiMe3 (3): Compound 2 (2.05 g,
5.75 mmol) was added to triethylamine (40 mL) and the resultant
mixture was deoxygenated. [Pd(PPh3)4] (20 mg, 0.010 mmol) and
CuI (30 mg, 0.15 mmol) were added, and the mixture was stirred at
room temperature for 5 min. Triisopropylsilylacetylene (1.35 g,
5.80 mmol) was then added and the mixture stirred at room tem-
perature for 12 h. The solvent was removed under reduced pres-
sure and the residue purified by column chromatography on silica,
eluting with petrol. The solvent was removed from the eluate to
1
give 3 as a colorless solid (2.25 g, 95%). Rf (petrol) = 0.50; H NMR
(400 MHz, CDCl3): d=7.16 (s, 2H, H15), 2.81 (q, JHH =7.6 Hz, 4H,
CH2), 1.22 (t, JHH =7.6 Hz, 6H, CH3), 1.13 (s, 18H, SiiPr3), 0.24 ppm (s,
6H, SiMe3); 13C{1H} NMR (101.5 MHz, CDCl3); d=146.9 (C16), 128.8
(C15), 122.5 (C17), 122.3 (C14), 105.4 (C13), 103.2 (C18), 100.2 (C19), 94.9
(C12), 28.1 (CH2), 18.6 (CH3-SiiPr3), 14.7 (CH3), 11.4 (Si-CH), 0.1 ppm
(SiMe3); MS (EI+): m/z (%): 410.3 (40) [M]+, 395.3 (20) [MÀMe]+,
367.2 (100) [MÀiPr]+; HRMS (ESI+): calcd for [C26H42Si2] 410.2825;
found: 410.2825; elemental analysis (%) calcd for C26H42Si2: C 76.02,
H 10.31; found: C 75.89, H 10.38.
fac-[Ir{N,C1’-(2,2’-NC5H4C6H3-5’-CꢀC-1-C6H2-3,5-Et2-4-CꢀCSiPr3)}3]
(7): Compound
6 (50.9 mg, 0.055 mmol) and 4 (66.4 mg,
0.196 mmol) were added to a deoxygenated mixture of triethyla-
mine (10 mL) and CH2Cl2 (20 mL). [Pd(PPh3)4] (12.7 mg, 0.011 mmol)
and CuI (2.3 mg, 0.012 mmol) were added and the yellow suspen-
sion was stirred for 3 days. After completion of the reaction (moni-
tored by TLC), the salt was removed by filtration and the filtrate
was concentrated under reduced pressure. The resulting residue
was purified by column chromatography (CH2Cl2/petrol 1:3), to
Chem. Eur. J. 2015, 21, 11843 – 11854
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11851
ꢀ 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Full Paper
afford 7 as a yellow powder (57.4 mg, 70%). 1H NMR (400 MHz,
CDCl3): d=7.91 (d, J=8, 3H, H4), 7.59–7.64 (m, 6H, H3 +H7), 7.45
(m, 3H, H1), 7.17 (s, 6H, H15), 7.13 (dd, J=8, 2, 3H, H8), 7.09 (d, J=
2, 3H, H10), 6.86 (m, 3H, H2), 5.28 (s, 1H, 0.5CH2Cl2), 2.78 (q, J=7.5,
12H, CH2), 1.22 (t, J=7.5 Hz, 18H, CH3), 1.13 ppm (s, 63H, SiiPr3);
13C{1H} NMR (101 MHz, CDCl3): d=165.9 (C5), 159.2 (C6), 147.0 (C16),
146.8 (C1), 144.1 (C11), 139.8 (C10), 136.1 (C3), 128.5 (C15), 124.3 (C8),
123.9 (C7), 123.7 (C9), 123.2 (C17), 122.1 (C14), 121.4 (C2), 119.4 (C4),
103.6 (C18), 99.5 (C19), 92.5 (C12), 90.0 (C13), 28.1 (CH2), 18.7 (CH3-
SiiPr3), 14.8 (CH3), 11.4 ppm (CH); IR (KBr): n˜ =2200 (CꢀC),
2144 cmÀ1 (CꢀCSi); HRMS (ESI+): calcd [C102H121IrN3Si3] 1664.8498;
found: [M]+ 1664.849; elemental analysis (%) calcd for
C102H120IrN3Si3.0.5CH2Cl2: C 72.12, H 7.14, N 2.46; found: C 71.69, H
7.46, N 2.23.
fac-[Ir{N,C1’-(2,2’-NC5H4C6H3-5’-CꢀC-1-C6H2-3,5-Et2-4-CꢀCC6H4-4-
CꢀCH)}3] (10): NaOH (5.7 mg, 0.14 mmol) was added to a solution
of 9 (40.9 mg, 0.023 mmol) in CH2Cl2 (15 mL) and MeOH (15 mL),
and the reaction mixture was stirred for 17 h. CH2Cl2 and H2O were
added, and the layers separated. The aqueous layer was extracted
with CH2Cl2 (10 mL”3) and the combined organic extracts were
washed with H2O (30 mL), and then dried over MgSO4. The solvent
was removed and the crude product was passed through a short
pad of silica, eluting with CH2Cl2/petrol (1:1) as eluent, and afford-
ing 10 as an orange powder (27.0 mg, 76%). Single crystals of 10
suitable for an X-ray diffraction study were grown by slow diffusion
of hexane into a mixed dichloromethane and chloroform solution
1
of 10 at 58C. H NMR (400 MHz, CDCl3): d=7.91 (d, J=8, 3H, H4),
7.60–7.65 (m, 6H, H3 +H7), 7.48–7.43 (m, 15H, H1 +H21 +H22), 7.22
(s, 6H, H15), 7.13 (m, 3H, H8), 7.10 (m, 3H, H10), 6.88 (m, 3H, H2),
2.83 (q, J=7.5, 12H, CH2), 3.17 (s, 3H, ꢀCH), 1.26 ppm (t, J=7.5,
18H, Me); 13C{1H} NMR (101 MHz, CDCl3): d=165.9 (C5), 159.2 (C6),
147.0 (C16), 146.3 (C1), 144.2 (C11), 139.8 (C10), 136.1 (C3), 132.1 (C21),
131.1 (C22), 128.6 (C15), 124.3 (C8), 124.2 (C7), 123.8 (C9), 123.7 (C17),
122.1 (C20 +C23), 121.6 (C2), 120.8 (C14), 119.4 (C4), 97.4 (C19), 92.8
(C12), 90.0 (C13), 88.9 (C18), 83.3 (C24), 78.8 (C25), 27.9 (CH2), 14.6 ppm
(CH3); IR (KBr): n˜ =3289 (ꢀCH), 2198 (CꢀC), 2105 cmÀ1 (CꢀC); HRMS
(ESI+): calcd [C99H72IrN3] 1495.5356; found: [M]+ 1495.5353; ele-
mental analysis (%) calcd for C99H72IrN3: C 79.49, H 4.85, N 2.81;
found: C 79.22, H 5.07, N 2.73.
fac-[Ir{N,C1’-(2,2’-NC5H4C6H3-5’-CꢀC-1-C6H2-3,5-Et2-4-CꢀCH)}3] (8):
NnBu4F (1m solution in THF, 0.03 mL) was added dropwise to a so-
lution of compound 7 (47.0 mg, 0.028 mmol) in CH2Cl2 (20 mL) and
the mixture stirred for 1 h. The solution was reduced in volume to
1 mL under reduced pressure and the product precipitated by ad-
dition of MeOH (100 mL). The solid was collected and then dis-
solved in CH2Cl2 and passed through a short pad of silica, using
CH2Cl2/petrol (1:1) as eluent. The eluate was reduced in volume
under vacuum, affording 8 as an orange powder (28.4 mg, 84%).
Single crystals of 8 submitted for elemental analysis and found to
be suitable for an X-ray diffraction study were grown by slow diffu-
sion of hexane into a dichloromethane solution of 8 at room tem-
[RuCl(dppe)2]PF6: trans-[RuCl2(dppe)2] (1.38 g, 1.42 mmol) and
NaPF6 (0.51 g, 3.0 mmol) were added to deoxygenated CH2Cl2
(20 mL) and the resultant mixture was stirred at 408C overnight.
The solvent volume was reduced under vacuum to ca. 5 mL and
the mixture passed through Celite, eluting with CH2Cl2. The solvent
was removed from the eluate to give a dark red solid (1.46 g,
95%). Identification of the product was confirmed by comparison
of spectral data with that from literature.[31] 31P NMR (121 MHz,
CDCl3): 56.7 (t), 84.8 ppm (t).
1
perature. H NMR (400 MHz, CDCl3): d=7.90 (d, J=8, 3H, H4), 7.58–
7.63 (m, 6H, H3 +H7), 7.45 (m, 3H, H1), 7.19 (s, 6H, H15), 7.11 (dd,
J=8, 2, 3H, H8), 7.08 (d, J=2, 3H, H10), 6.85 (m, 3H, H2), 3.46 (s, 3H,
ꢀCH), 2.75 (q, J=7.5, 12H, CH2), 1.19 ppm (t, J=7.5, 18H, Me);
13C{1H} NMR (101 MHz, CDCl3): d=165.9 (C5), 159.2 (C6), 147.0 (C16),
147.0 (C1), 144.2 (C11), 139.8 (C10), 136.1 (C3), 128.4 (C15), 124.2 (C8),
123.8 (C7), 123.7 (C9), 123.6 (C17), 122.1 (C14), 120.0 (C2), 119.4 (C4),
92.6 (C12), 89.8 (C13), 85.5 (C19), 80.6 (C18), 27.7 (CH2), 14.6 ppm
(CH3); IR (KBr): n˜ =3287 (ꢀCH), 2199 (CꢀC), 2094 cmÀ1 (CꢀC); HRMS
(ESI+): calcd [C75H60IrN3Na] 1218.4314; found: [M+Na]+ 1218.4347;
elemental analysis (%) calcd for C75H60IrN3.0.5CH2Cl2: C 73.25, H
4.97, N 3.39; found: C 73.31, H 5.29, N 3.30.
fac-[Ir{N,C1’-(2,2’-NC5H4C6H3-5’-CꢀC-1-C6H2-3,5-Et2-4-CꢀCC6H4-4-
CꢀC-trans-[RuCl(dppe)2])}3] (11): [RuCl(dppe)2]PF6 (88.8 mg,
0.082 mmol) was added to a solution of 10 (30.8 mg, 0.020 mmol)
in CH2Cl2 (20 mL). The resultant mixture was stirred for 16 h, con-
centrated to 1 mL under reduced pressure, and then added drop-
wise to 100 mL ether, affording an orange precipitate which was
collected and redissolved in CH2Cl2. Triethylamine (1 mL) was
added and the mixture was stirred for 5 min. The solution was
then concentrated to 1 mL under reduced pressure, and added to
petrol (50 mL), precipitating the product. The solid was collected
and washed with MeOH, to give 11 as a yellow powder (88.4 mg,
fac-[Ir{N,C1’-(2,2’-NC5H4C6H3-5’-CꢀC-1-C6H2-3,5-Et2-4-CꢀCC6H4-4-
CꢀCSiMe3)}3] (9): Compound 8 (49.2 mg, 0.041 mmol) and [(4-iodo-
phenyl)ethynyl]trimethylsilane (54.4 mg, 0.18 mmol) were added to
a deoxygenated mixture of triethylamine (10 mL) and CH2Cl2
(20 mL). Pd(PPh3)4 (10.1 mg, 0.0080 mmol) and CuI (1.9 mg,
0.0090 mmol) were added and the resultant yellow suspension was
stirred for 27 h. Upon completion of the reaction (as monitored by
TLC), the salt was removed by filtration and the solvent was re-
moved from the filtrate under reduced pressure. The residue was
purified by silica gel column chromatography (CH2Cl2/petrol, 2:3),
1
90%). H NMR (400 MHz, CDCl3): d=7.92 (d, J=8, 3H, H4), 7.66 (d,
J=8.0, 3H, H7), 7.63 (m, 3H, H3), 7.47 (m, 33H, H1 +H21 +Ho), 7.30
(m, 30H, Ho’+H15), 7.18 (m, 30H, H8 +H10 +Hp +Hp’), 6.97 (m, 48H,
Hm +Hm’), 6.88 (m, 3H, H2), 6.58 (d, J=8, 6H, H21), 5.32 (s, 2H,
CH2Cl2), 2.88 (q, J=8, 12H, CH2), 2.67 (m, 24H, H26), 1.33 ppm (t,
J=8, 18H, CH3); 13C{1H} NMR (101 MHz, CDCl3): d=165.9 (C5), 159.3
(C6), 147.0 (C16), 145.9 (C1), 144.2 (C11), 139.9 (C10), 136.4 (m, Ci+Ci’),
136.1 (C3), 134.4 (Co), 134.2 (Co’), 130.6 (C22), 130.2 (C23), 129.9 (C22),
128.9 (Cp/Cp’), 128.8 (Cp/Cp’), 128.6 (C15), 127.2 (Cm/Cm’), 127.0 (Cm/
Cm’), 124.3 (C8), 124.0 (C7), 123.7 (C9), 122.8 (C17), 122.1 (C2), 121.8
(C14), 119.4 (C4), 117.3 (C21), 114.5 (C24), 99.4 (C18), 92.5 (C12), 90.2
(C13), 86.9 (C19), 30.8 (m, C26), 27.9 (CH2), 14.7 ppm (CH3). C25 not ob-
served. 31P{1H} NMR (161.9 MHz, CDCl3): d=50.0 ppm; IR (KBr): n˜ =
2194 (CꢀC), 2053 cmÀ1 (CꢀCRu); elemental analysis (%) calcd for
C255H213Cl3IrN3P12Ru3.CH2Cl2: C 70.23, H 4.95, N 0.96; found: C 70.32,
H 4.95, N 0.97.
to afford
9
as an orange powder (47.8 mg, 68%). 1H NMR
(400 MHz, CDCl3): d=7.91 (br d, J=8, 3H, H4), 7.60–7.65 (m, 6H,
H3 +H7), 7.46–7.40 (m, 15H, H1 +H21 +H22), 7.22 (s, 6H, H15), 7.13
(dd, J=8, 2, 3H, H8), 7.10 (d, J=2, 3H, H10), 6.84 (m, 3H, H2), 2.83
(q, J=7.5, 12H, CH2), 1.26 (t, J=7.5, 18H, Me), 0.26 ppm (s, 27H,
SiMe3); 13C{1H} NMR (100.6 MHz, CDCl3): d=165.9 (C5), 159.2 (C6),
147.0 (C16), 146.3 (C1), 144.2 (C11), 139.8 (C10), 136.1 (C3), 131.9 (C21),
131.0 (C22), 128.5 (C15), 124.3 (C8), 123.9 (C7), 123.7 (C9), 123.6 (C17),
122.7 (C20 +C23), 122.1 (C2), 120.8 (C14), 119.4 (C4), 104.7 (C25), 97.6
(C24), 96.1 (C19), 92.8 (C12), 90.0 (C13), 88.8 (C18), 27.8 (CH2), 14.6
(CH3), 0.07 ppm (SiMe3); IR (KBr): n˜ =2197 (CꢀC), 2154 cmÀ1 (CꢀCSi);
HRMS (ESI+): calcd [C108H96IrN3Si3] 1711.6542; found: [M]+
1711.6544; elemental analysis (%) calcd for C108H96IrN3Si3: C 75.75,
H 5.65, N, 2.45; found: C 75.65, H 5.70, N 2.49.
X-ray structure determinations: Intensity data were collected
using an Enraf–Nonius KAPPA CCD at 200 K with MoKa radiation
Chem. Eur. J. 2015, 21, 11843 – 11854
www.chemeurj.org
11852
ꢀ 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Full Paper
(l=0.7170 Š). Suitable crystals were immersed in viscous hydrocar-
bon oil and mounted on glass fibers which were mounted on the
diffractometer. Using psi and omega scans, Nt (total) reflections
were measured, which were reduced to No unique reflections, with
Fo >2s(Fo) being considered observed. Data were initially pro-
cessed and corrected for absorption using the programs DENZO[32]
and SORTAV.[33] The structures were solved using direct methods,
and observed reflections were used in least squares refinement on
F2, with anisotropic thermal parameters refined for non-hydrogen
atoms. Hydrogen atoms were constrained in calculated positions
and refined with a riding model. Structure solutions and refine-
ments were performed using the programs SHELXS-97 and
SHELXL-97[34] through the graphical interface Olex2,[35] which was
also used to generate the figures.
groups on one ligand (C216–C220, C220–C221, and C218–C222,
C222–C223). Anisotropic displacement parameter restraints and/or
constraints were applied to all ethyl carbons in the structure, as
well as
a phenyl ring (C326–C331). CCDC 1005586, 1005587,
1005588, 1005589 and 1005590 contain the supplementary crystal-
lographic data for this paper. These data are provided free of
charge by The Cambridge Crystallographic Data Centre
Acknowledgements
We thank the Australian Government Department of Innova-
tion, Industry, Science, Research, and Tertiary Education
(DIISRTE) and the Government of India Department of Science
and Technology for support through the Australia-India Strate-
gic Research Fund, and the Australian Research Council (ARC)
for support through the Discovery Project scheme. H.V. thanks
the Chinese Government China Scholarship Council (CSC) and
the Australian National University (ANU) for an ANU-CSC Schol-
arship, M.P.C. thanks the Australian Research Council (ARC) for
an ARC Australian Research Fellowship, and M.G.H. thanks the
ARC for an ARC Australian Professorial Fellowship.
Crystal data for 2: C15H21ISi, M=356.31, colorless plate, 0.13”0.12”
0.04 mm3, monoclinic, space group P21/c (No. 14), a=6.5602(13),
b=25.698(5), c=9.7164(19) Š, b=95.17(3)8, V=1631.4(6) Š3, Z=4,
1calcd =1.451 gcmÀ3, F000 =712, 2qmax =55.08, 32298 reflections col-
lected, 3760 unique (Rint =0.0545). Final GoF=1.188, R1=0.0274,
wR2=0.0640, R indices based on 3058 reflections with I>2s(I) (re-
finement on F2), 159 parameters, 0 restraints, m=2.017 mmÀ1. Crys-
tal data for 5: C88H56Cl4I8Ir4N8, M=3151.21, yellow block, 0.12”
3
¯
0.10”0.07 mm , triclinic, space group P1 (No. 2), a=13.395(3), b=
14.257(3), c=30.048(6) Š, a=99.13(3), b=91.28(3), g=90.57(3)8,
V=5663(2) Š3, Z=2, 1calcd =1.848 gcmÀ3, F000 =2880, 2qmax =55.08,
25976 reflections collected, 25976 unique (Rint =0.0700). Final
GoF=0.973, R1=0.0370, wR2=0.0855, R indices based on 17278
reflections with I>2s(I) (refinement on F2), 1009 parameters, 0 re-
straints, m=6.998 mmÀ1. Crystal data for 6: 2(C33H21I3IrN3).C3H6O,
M=2122.93, yellow block, 0.12”0.10”0.08 mm3, triclinic, space
Keywords: heterometallic complexes · iridium · ligand design ·
nonlinear optics · ruthenium
[1] a) M. A. Baldo, M. E. Thompson, S. R. Forrest, Nature 2000, 403, 750;
b) A. Beeby, S. Bettington, I. D. W. Samuel, Z. Wang, J. Mater. Chem.
2003, 13, 80; c) C. Ulbricht, B. Beyer, C. Friebe, A. Winter, U. S. Schubert,
Adv. Mater. 2009, 21, 4418; d) Y.-C. Zhu, L. Zhou, H.-Y. Li, Q.-L. Xu, M.-Y.
Teng, Y.-X. Zheng, J.-L. Zuo, H.-J. Zhang, X.-Z. You, Adv. Mater. 2011, 23,
4041; e) C.-H. Yang, M. Mauro, F. Polo, S. Watanabe, I. Muenster, R. Frçh-
lich, L. De Cola, Chem. Mater. 2012, 24, 3684; f) R. Tao, J. Qiao, G. Zhang,
L. Duan, L. Wang, Y. Qiu, J. Phys. Chem. C 2012, 116, 11658.
¯
group P1 (No. 2), a=10.680(2), b=12.761(3), c=13.384(3) Š, a=
79.83(3), b=72.15(3), g=66.28(3)8, V=1586.5(6) Š3, Z=1, 1calcd
=
2.222 gcmÀ3, F000 =984, 2qmax =55.98, 43857 reflections collected,
7569 unique (Rint =0.0489). Final GoF=1.062, R1=0.0272, wR2=
0.0676, R indices based on 6942 reflections with I>2s(I) (refine-
ment on F2), 389 parameters, 0 restraints, m=7.157 mmÀ1. Crystal
[2] M. Zaarour, A. Singh, C. Latouche, J. A. G. Williams, I. Ledoux-Rak, J.
Zyss, A. Boucekkine, H. Le Bozec, V. Guerchais, C. Dragonetti, A. Colom-
bo, D. Roberto, A. Valore, Inorg. Chem. 2013, 52, 7987.
data for 8: C73H63IrN3, M=1195.46, orange plate, 0.10”0.09”
3
¯
0.02 mm , triclinic, space group P1 (No. 2), a=14.190(3), b=
15.793(3), c=16.255(3) Š, a=99.61(3), b=107.73(3), g=104.86(3)8,
[3] a) M. P. Cifuentes, C. E. Powell, J. P. Morrall, A. M. McDonagh, N. T. Lucas,
M. G. Humphrey, M. Samoc, S. Houbrechts, I. Asselberghs, K. Clays, A.
Persoons, T. Isoshima, J. Am. Chem. Soc. 2006, 128, 10819; b) G. T.
Dalton, M. P. Cifuentes, S. Petrie, R. Stranger, M. G. Humphrey, M.
Samoc, J. Am. Chem. Soc. 2007, 129, 11882; c) K. A. Green, M. P. Ci-
fuentes, T. C. Corkery, M. Samoc, M. G. Humphrey, Angew. Chem. Int. Ed.
2009, 48, 7867; Angew. Chem. 2009, 121, 8007; d) K. A. Green, M. P. Ci-
fuentes, M. Samoc, M. G. Humphrey, Coord. Chem. Rev. 2011, 255, 2530.
[4] See, for example: a) N. T. Lucas, M. P. Cifuentes, L. T. Nguyen, M. G. Hum-
phrey, J. Cluster Sci. 2001, 12, 201; b) G. Grelaud, M. P. Cifuentes, T.
Schwich, G. Argouarch, S. Petrie, R. Stranger, F. Paul, M. G. Humphrey,
Eur. J. Inorg. Chem. 2012, 65; c) L. Norel, M. Feng, K. Bernot, T. Roisnel, T.
Guizouarn, K. Costuas, S. Rigaut, Inorg. Chem. 2014, 53, 2361.
[5] a) A. M. McDonagh, M. G. Humphrey, M. Samoc, B. Luther-Davies, S.
Houbrechts, T. Wada, H. Sasabe, A. Persoons, J. Am. Chem. Soc. 1999,
121, 1405; b) C. E. Powell, J. P. Morrall, S. A. Ward, M. P. Cifuentes, E. G. A.
Notaras, M. Samoc, M. G. Humphrey, J. Am. Chem. Soc. 2004, 126,
12234; c) M. Samoc, J. P. Morrall, G. T. Dalton, M. P. Cifuentes, M. G. Hum-
phrey, Angew. Chem. Int. Ed. 2007, 46, 731; Angew. Chem. 2007, 119,
745; d) R. L. Roberts, T. Schwich, T. C. Corkery, M. P. Cifuentes, K. A.
Green, J. D. Farmer, P. J. Low, T. B. Marder, M. Samoc, M. G. Humphrey,
Adv. Mater. 2009, 21, 2318.
V=3232.7(11) Š3, Z=2, 1calcd =1.228 gcmÀ3
, F000 =1216, 2qmax =
55.08, 14809 reflections collected, 14809 unique (Rint =0.1080).
Final GoF=1.028, R1=0.0803, wR2=0.2000, R indices based on
10350 reflections with I>2s(I) (refinement on F2), 682 parameters,
0 restraints, m=2.107 mmÀ1. Crystal data for 10: C99H72IrN3, M=
1495.80, orange plate, 0.11”0.10”0.04 mm3, triclinic, space group
¯
P1 (No. 2), a=14.545(3), b=17.415(4), c=19.879(4) Š, a=88.51(3),
b=83.98(3), g=82.48(3)8, V=4964.0(17) Š3, Z=2, 1calcd
=
1.001 gcmÀ3, F000 =1528, 2qmax =55.08, 22732 reflections collected,
22732 unique (Rint =0.0607). Final GoF=1.069, R1=0.0669, wR2=
0.2002, R indices based on 17611 reflections with I>2s(I) (refine-
ment on F2), 748 parameters, 56 restraints, m=1.384 mmÀ1
.
Variata: For 5, disordered lattice dichloromethane and hexane mol-
ecules could not be modelled satisfactorily, and were removed
from the refinement using PLATON SQUEEZE.[36] For 8, disordered
lattice dichloromethane molecules could not be modelled satisfac-
torily, and were removed from the refinement using PLATON
SQUEEZE.[36] Constraints were applied to the anisotropic displace-
ment parameters of ethyl group atoms C120–C123, and C320–
C323. For 10, the crystal contained very large amounts of disor-
dered lattice solvents (chloroform, dichloromethane and hexane),
which could not be satisfactorily modelled. These solvent mole-
cules were removed from the refinement using PLATON
SQUEEZE.[36] Bond distance restraints were applied to the ethyl
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Received: March 10, 2015
Published online on July 14, 2015
Chem. Eur. J. 2015, 21, 11843 – 11854
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11854
ꢀ 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim