Metal-containing amphiphiles: Orthometallated iridium(III) complexes with substituted 6'-phenyl-2,2'-bipyridines

Article abstract of DOI:10.1002/(SICI)1099-0682(200005)2000:5<1039::AID-EJIC1039>3.0.CO;2-2

The reaction of 4'-functionalized 6'-phenyl- 2,2'-bipyridine ligands (L- n) with the dimer [(ppy)₂IrCl]₂ (ppy = 2-phenylpyridine anion) and subsequent counterion exchange affords a new series of cationic orthometallated iridium(III) complexes, [(ppy)₂Ir(L-n)][PF₆] (1-5), which have been characterized by spectroscopic methods. These complexes have a large shape anisotropy and significant amphiphilic character. The crystal structure of 4 has been determined by X-ray diffraction.

Full text of DOI:10.1002/(SICI)1099-0682(200005)2000:5<1039::AID-EJIC1039>3.0.CO;2-2

FULL PAPER
Metal-Containing Amphiphiles: Orthometallated Iridium(III) Complexes with
Substituted 6Ј-Phenyl-2,2Ј-bipyridines
Francesco Neve*[a] and Alessandra Crispini[a]
Keywords: Iridium / Amphiphiles / N ligands / Structure elucidation
The reaction of 4Ј-functionalized 6Ј-phenyl-2,2Ј-bipyridine li-
[(ppy)2Ir(L-n)][PF6] (1–5), which have been characterized by
gands (L-n) with the dimer [(ppy)2IrCl]2 (ppy = 2-phenylpyr- spectroscopic methods. These complexes have a large shape
idine anion) and subsequent counterion exchange affords a
new series of cationic orthometallated iridium(III) complexes,
anisotropy and significant amphiphilic character. The crystal
structure of 4 has been determined by X-ray diffraction.
Introduction
which, at the same time, may afford species with a high
aspect ratio (i.e. width-to-length ratio). Here we report on
the synthesis and structural characterization of the series of
IrIII cationic complexes [(ppy)2Ir(L-n)][PF6] (1–5) which are
based on the ligands L-n (n ϭ 1–5) and which also contain
the orthometallated {(ppy)2Ir} fragment (ppy ϭ orthomet-
allated 2-phenylpyridine). The synthesis of ligands L-2 and
L-3 is also reported here for the first time.
The coexistence of distinct hydrophobic and hydrophilic
moieties in the same structure is the key factor inducing
segregation of dissimilar parts thus generating supramolec-
ular anisotropic assemblies. In this light amphiphilic molec-
ules, either neutral or ionic, are known to self-organise into
a great variety of supramolecular structures both in solu-
tion and in the solid state.[1,2] On the other hand, since the
incorporation of a transition metal ion into the polar part
may impart additional features to the resulting amphiphile,
metal coordination has been considered a simple way of
preparing novel classes of amphiphiles. Recently, redox-act-
ive,[3,4] photo-active[3] or simply surface-active[5] amphi-
philic complexes have been prepared. In addition, liquid-
crystal behaviour has also been described for both thermo-
tropic (temperature-active)[6,7] and lyotropic (concentration-
active)[8] metal-containing amphiphiles.
We recently reported the synthesis of new 6Ј-phenyl-2,2Ј-
bipyridines bearing promesogenic substituents in the 4Ј-po-
sition.[9] Our investigation showed that strongly aniso-
metric, photoactive complexes with square-planar geometry
could be obtained with these ligands,[9,10] which eventually
exhibited liquid-crystalline properties.[11] In order to pre-
pare new amphiphilic complexes, we have focused our at-
tention on 6Ј-phenyl-2,2Ј-bipyridine ligands that bear
highly hydrophobic substituents (L-n in Scheme 1) and
Anisometric Ligands
The functionalized L-n ligands present either alkoxy
(–OR) or ester (–COOR or –OCOR) functions in the peri-
phery of the N,N-chelating site (Scheme 1). Such an ar-
rangement leads to the formation of ligands with a large
anisometry (i.e. shape anisotropy) provided a terminal
group ensures the right content of aliphatic carbon atoms.
Derivatization of the 6Ј-phenyl-2,2Ј-bipyridine moiety
can be accomplished following two different synthetic strat-
egies. The build-up of the 2,2Ј-bipyridine skeleton through
a Kröhnke-type[12] synthesis may follow (see the prepara-
tion of L-2) or precede the introduction of the peripheral
substituent usually through condensation reactions (as for
L-3). The latter strategy seems to be more valuable since it
potentially allows a wide variety of derivatives to be pre-
pared.[11]
Orthometallated Iridium(III) Complexes
Bridge-splitting reactions of [(ppy)2IrCl]2 with N,N-che-
lating ligands are commonplace when the incorporation of
the orthometallated {(ppy)2Ir} fragment into a mononu-
clear[13] or multinuclear[14] species is desired. Likewise, the
cationic complexes 1–5 were obtained in good yield upon
reaction of the dimer [(ppy)2IrCl]2 with the L-n ligands un-
der reflux conditions in a dichloromethane/methanol mix-
ture (Scheme 2). Metathesis of the chloride counterion with
excess NH4PF6 gave the final products [(ppy)2Ir(L-n)][PF6].
The 1H NMR spectroscopic characterization of 1–5
showed that only a single isomer resulted from the reaction.
From the NMR evidence it follows that both the pyridine
Scheme 1
[a]
`
Dipartimento di Chimica, Universita della Calabria
I-87030 Arcavacata di Rende (CS), Italy
Fax: (internat.) ϩ 39-0984/492-044
E-mail: f.neve@unical.it
Eur. J. Inorg. Chem. 2000, 1039Ϫ1043
WILEY-VCH Verlag GmbH, D-69451 Weinheim, 2000
1434Ϫ1948/00/0505Ϫ1039 $ 17.50ϩ.50/0
1039

F. Neve, A. Crispini
FULL PAPER
parameters and the same configuration at the metal
(Table 1). Figure 1 shows a perspective drawing of one of
the cations (cation 1).
˚
Table 1. Selected bond lengths [A] and angles [°] for complex 4
Cation 1
Cation 2
Ir(1)–N(1)
2.06(1)
1.98(1)
2.14(1)
2.21(1)
2.03(1)
2.00(1)
96.6(4)
82.8(6)
87.9(4)
171.9(4)
99.4(4)
88.7(4)
93.1(6)
75.9(4)
94.0(5)
169.9(5)
92.5(5)
79.9(5)
175.3(4)
108.7(4)
81.4(5)
Ir(2)–N(5)
2.05(1)
2.07(1)
2.16(1)
2.24(1)
2.02(1)
2.05(1)
93.7(4)
80.7(4)
93.3(4)
169.7(4)
96.0(4)
92.7(4)
94.4(3)
75.6(4)
93.8(3)
167.7(3)
89.7(5)
80.7(5)
174.4(4)
109.0(4)
82.1(4)
Ir(1)–N(2)
Ir(2)–N(6)
Ir(1)–N(3)
Ir(2)–N(7)
Ir(1)–N(4)
Ir(2)–N(8)
Ir(1)–C(6)
Ir(2)–C(70)
Ir(1)–C(17)
Ir(2)–C(81)
N(1)–Ir(1)–N(4)
N(1)–Ir(1)–C(6)
N(1)–Ir(1)–N(3)
N(2)–Ir(1)–N(1)
N(2)–Ir(1)–N(3)
N(2)–Ir(1)–N(4)
N(2)–Ir(1)–C(6)
N(3)–Ir(1)–N(4)
C(6)–Ir(1)–N(3)
C(6)–Ir(1)–N(4)
C(17)–Ir(1)–N(1)
C(17)–Ir(1)–N(2)
C(17)–Ir(1)–N(3)
C(17)–Ir(1)–N(4)
C(17)–Ir(1)–C(6)
N(5)–Ir(2)–N(8)
N(5)–Ir(2)–C(70)
N(5)–Ir(2)–N(7)
N(6)–Ir(2)–N(5)
N(6)–Ir(2)–N(7)
N(6)–Ir(2)–N(8)
N(6)–Ir(2)–C(70)
N(7)–Ir(2)–N(8)
C(70)–Ir(2)–N(7)
C(70)–Ir(2)–N(8)
C(81)–Ir(2)–N(5)
C(81)–Ir(2)–N(6)
C(81)–Ir(2)–N(7)
C(81)–Ir(2)–N(8)
C(81)–Ir(2)–C(70)
Scheme 2
rings of L are involved in the coordination and no
metallation has occurred. Although no attempt was made
to assign all the resonances of the spectra (e.g. the proton
spectrum of 3 shows some 19 distinct signals or groups of
signals in the aromatic region), it is apparent that all the
complexes belong to an isostructural series, where the two
metallated ppy ligands for each complex experience
through-space shielding effects different from each other.
Complexes 1–5 are insoluble in water, but reasonably sol-
uble in dichloromethane or chloroform (with 1 and 2 show-
ing the best solubility) affording air-stable solutions. All
complexes are also very soluble in acetonitrile and solutions
of 1–5 in this solvent were used to measure the electronic
absorption spectra. The absorption spectra of all the com-
plexes are dominated by a broad band peaking in the UV
region and extending to the visible. The maximum of this
band is around 270 nm, and receives its main contribution
from ligand-centred LC transitions involving the metallated
phenylpyridine ligands.[15] The absorptions which appear as
shoulders of the main band probably arise from spin-al-
lowed MLCT transitions. In particular spin-allowed IrǞ(L-
n) CT transitions probably dominate the lowest energy por-
tion of the spectra.[13,16,17] Finally, the very weak features
reaching into the visible region may correspond to formally
spin-forbidden MLCT transitions. A more detailed assign-
ment of the electronic absorption spectra of 1–5 is, however,
beyond the scope of the present work.
Although the study revealed several causes of disorder
which affected the general accuracy, the molecular and crys-
tal features are well established. The metal centre displays
a slightly distorted octahedral geometry with trans angles
at the IrIII centre spanning the range 167–176°. The C-
donor atoms of the metallated ppy ligands adopt a cis con-
figuration as in the parent dimer,[18] showing a remarkable
trans-influence which is in good agreement with similar ob-
servations on related complexes[13b,17,19,20]. The pyridine
rings of the L-4 ligand are almost coplanar (dihedral angle
between the two mean planes of 10°), whereas the rota-
tionally free 6Ј-phenyl ring is found to be nearly orthogonal
to the mean plane of the coordinated L-4 ligand (tilt angle
of 82°). The hexyloxy chain of cation 1 deviates from a
fully trans-planar conformation with the C(59)–C(60) and
C(62)–C(63) bonds in a gauche conformation (66 and 69°,
respectively). The corresponding chain of cation 2 shows a
slightly different sequence of conformations (i.e. tttgg).
The mutual orientation between the two molecules in the
asymmetric unit is such that the central pyridine ring of the
L-4 ligand of one cation faces the 4Ј-phenyl ring of the se-
cond cation thus resulting in a slipped head-to-tail arrange-
ment. The packing diagram shows a layered structure with
layers stacking along the b axis (Figure 2). In particular,
the alternating tilt of the hydrocarbon chain axes along b
generates a herringbone motif.
Crystal Structure of 4
Thermal Behaviour of Complexes 1–5
Despite the poor tendency to crystallize of the remaining
members of the series 1–5, single crystals of 4 were easily
Since some of the free L-n ligands are thermotropic li-
obtained at ambient temperature by slow diffusion of meth- quid crystals,[11] we tried to ascertain whether complexes 1–
anol into chloroform solutions of the complex. An X-ray 5 displayed a thermotropic phase behaviour using thermal
analysis showed the presence in the unit cell of two crystal- polarizing optical microscopy and differential scanning ca-
lographically independent molecules with similar metric lorimetry (DSC) techniques. Although some notable differ-
1040
Eur. J. Inorg. Chem. 2000, 1039Ϫ1043

Metal-Containing Amphiphiles
FULL PAPER
Figure 1. A perspective view and numbering scheme of cation 1 of complex 4; all atoms are shown as arbitrarily sized circles; H atoms
omitted for clarity
Experimental Section
Materials and Methods: Ammonium acetate (Lancaster), 1-[2-oxo-
2-(phenyl)ethyl]pyridinium bromide [hereafter N-(phenacyl)pyridi-
nium bromide] (Lancaster), cholesterol (Lancaster), 1,3-dicyclohex-
ylcarbodiimide (Aldrich) and 4-(pyrrolidino)pyridine (Aldrich)
were used as received. The complex [(ppy)2IrCl]2 was prepared as
described in the literature.[16a] The diester ligands 4Ј-{4-[4-
(hexyloxybenzoyloxy)benzoyloxy]phenyl}-6Ј-phenyl-2,2Ј-bipyr-
idine (L-4) and 4Ј-{4-[4-(dodecyloxybenzoyloxy)benzoyloxy]-
phenyl}-6Ј-phenyl-2,2Ј-bipyridine (L-5) were obtained according to
a method recently devised in our laboratory.[11] The synthesis of 4Ј-
(4ЈЈ-carboxyphenyl)-6Ј-phenyl-2,2Ј-bipyridine to be used as starting
material in the preparation of the ligand L-3 has been reported
elsewhere.[20] All reactions and manipulations of the complexes
1
were performed in air. – H NMR spectra were recorded at room
temperature on a 300-MHz Bruker AC300 spectrometer. Chemical
shifts are reported relative to internal TMS. – IR spectra were ob-
tained as nujol mulls or KBr pellets on a Perkin–Elmer System-
2000 FT-IR spectrophotometer. – Optical observations were car-
ried out with a Zeiss Axioskop polarizing microscope equipped
with a Linkam CO 600 heating stage and a temperature control
unit. – Melting temperatures were measured by differential scan-
ning calorimetry (DSC) with a Perkin–Elmer DSC-7. – Elemental
analyses of the new complexes were performed by the Microanalyt-
ical Service of our department.
Figure 2. Packing diagram of 4 viewed down the a axis
ences were observed, both techniques confirmed the ab-
sence of liquid-crystalline behaviour along the whole series
of complexes. Thus, while 1 and 4 clearly melt to an iso-
tropic liquid, compounds 2 and 5 very smoothly become
plastic solids on heating (above 140 and 170 °C, respect-
ively) with fading birefringence. No clearing (or decomposi-
tion) is then observed till ca. 300°C, and cooling affords
only glassy solids. The behaviour of 3 is even less clear,
roughly matching that of 2.
The above observations show that, whereas the cations
[(ppy)2Ir(L-n)]ϩ possess a suitable polar/apolar ratio of
their molecular parts which may guarantee phase separa-
tion, the bulkiness of the six-coordinate head-group in 1–5
somewhat reduces the structural anisotropy of the L-n li-
gands and no compensation for such a reduction is available
from dipolar and/or dispersive interactions in the melt. In
conclusion, we have prepared ionic metal-containing am-
phiphiles which failed to display mesogenic properties as
pure species. Other properties are more predictable (e.g.
photoluminescence) although unexplored. Attempts are in
progress to design materials with improved properties.
4Ј-(4ЈЈ-Octadecyloxyphenyl)-6Ј-phenyl-2,2Ј-bipyridine (L-2): The li-
gand L-2 was prepared in a way similar to that for the previously
reported L-1.[10] A solution of N-(phenacyl)pyridinium bromide
(0.52 g, 1.88 mmol), 1-(2-pyridyl)-3-[4-(octadecyloxy)phenyl]p-
ropen-1-one (0.90 g, 1.88 mmol), and ammonium acetate (1.45 g,
18.8 mmol) in methanol (25 mL) was heated to reflux for 8 h. A
brown precipitate was obtained after cooling the reaction mixture
to 0 °C. Purification of the crude solid by column chromatography
on SiO2 (CH2Cl2 and diethyl ether as consecutive eluents) yielded
the product after workup as a pinkish-brown flaky solid in low
1
yield (18%). M.p. 92 °C. – H NMR (300 MHz, CDCl3): δ ϭ 8.72
(br d, 1 H), 8.69 (d, J ϭ 8.1 Hz, 1 H), 8.62 (d, J ϭ 1.4 Hz, 1 H),
8.20 (m, 2 H), 7.96 (d, J ϭ 1.4 Hz, 1 H), 7.86 (t d, J ϭ 7.6 Hz, J ϭ
5.0 Hz, J ϭ 1.7 Hz, 1 H), 7.79 (d, J ϭ 8.6 Hz, 2 H), 7.52 (m, 3 H),
7.34 (m, 1 H), 4.03 (t, 2 H, OCH2), 1.80 (m, 2 H, OCH2CH2),
1.49–1.20 [m, 30 H, (CH2)15], 0.88 (t, 3 H, CH3).
4Ј-[(Cholesteryloxycarbonyl)phenyl]-6Ј-phenyl-2,2Ј-bipyridine (L-3):
Cholesterol (0.08 g, 0.2 mmol), 4Ј-(4ЈЈ-carboxyphenyl)-6Ј-phenyl-
2,2Ј-bipyridine (0.07 g, 0.2 mmol), 1,3-dicyclohexylcarbodiimide
(0.04 g, 0.2 mmol) and 4-(pyrrolidino)pyridine (0.004 g, 0.03 mmol)
were suspended in degassed CH2Cl2 (30 mL) and stirred under a
dry nitrogen atmosphere for 24 h. A white precipitate was removed
Eur. J. Inorg. Chem. 2000, 1039Ϫ1043
1041

F. Neve, A. Crispini
FULL PAPER
by filtration, and the colourless filtrate was consecutively washed
with 5% acetic acid (20 mL) and water (2 ϫ 20 mL). The organic
phase was dried over sodium sulfate and rotary-evaporated to dry-
ness. The desired product was obtained as a white solid after puri-
fication of the solid residue by column chromatography (SiO2,
UV/Vis (acetonitrile): λmax (log ε) ϭ 270 nm (4.61), 320sh (4.14),
380sh (3.60). – 1H NMR (300 MHz, CD3CN): δ ϭ 8.83 (br s, 1 H,
3Ј-H), 8.74 (d, J ϭ 8.2 Hz, 1 H, 3-H), 8.31 (d, J ϭ 8.5 Hz, 2 H),
8.22–8.02 (m, 5 H), 7.98–7.83 (m, 6 H), 7.80 (br s, 1 H, 5-H), 7.68
(d, J ϭ 5.7 Hz, 1 H), 7.61 (d, J ϭ 7.6 Hz, 1 H), 7.54–7.44 (m, 5
CH2Cl2/3% MeOH). Yield: 31%. – IR (KBr): ν˜ ϭ 1716 cm–1 H), 7.31 (d, J ϭ 7.8 Hz, 1 H), 7.17–7.06 (m, 4 H), 6.95 (m, 2 H),
(CO). – 1H NMR (300 MHz, CDCl3): δ ϭ 8.74–8.69 (m, 2 H), 8.66 6.83 (br t, 1 H), 6.77 (t, J ϭ 7.8 Hz, 2 H), 6.66 (v br s, 2 H), 6.58
(br s, 1 H), 8.23–8.17 (m, 4 H), 8.00 (br s, 1 H), 7.90–7.86 (m, 3
H), 7.57–7.45 (m, 3 H), 7.36 (m, 1 H), 5.44 (br d, 1 H, chol.), 4.92
(m, 1 H, chol.), 2.53–0.68 (m, 43 H, chol.).
(t, J ϭ 7.4 Hz, 1 H), 6.38 (t, J ϭ 7.4 Hz, 1 H), 5.97 (d, J ϭ 7.7 Hz,
1 H), 5.58 (d, J ϭ 7.7 Hz, 1 H), 4.12 (t, 2 H, OCH2), 1.80 (m, 2
H, OCH2CH2), 1.41–1.36 [m, 6 H, (CH2)3], 0.94 (t, 3 H, CH3). –
C64H52F6IrN4O5P (1294): calcd. C 59.39, H 4.05, N 4.33; found C
59.30, H 4.17, N 4.21.
General Procedure for the Synthesis of the Complexes 1–5: A stirred
suspension of the appropriate ligand (0.06 mmol) and [(ppy)2IrCl]2
(0.03 mmol) in CH2Cl2/MeOH (10 ml; 6:4) was heated to reflux.
Clear orange or brown solutions were observed within 10 min.
After 2 h, the solution was allowed to cool to ambient temperature.
Then, a saturated solution of a five-fold excess (based on the li-
gand) of NH4PF6 in MeOH was added and stirring was continued
for a further 30 min. The products were isolated after partial evap-
oration of the solvents under reduced pressure, washed with meth-
anol and diethyl ether, and dried in vacuo.
[(ppy)2Ir(L-5)][PF6] (5): Yield: 75%, brownish orange powder. – IR
(KBr): ν˜ ϭ 1736 cm–1 (CO), 842 (PF). – UV/Vis (acetonitrile): λmax
(log ε) ϭ 270 nm (4.71), 321sh (4.27), 381sh (3.72). – 1H NMR
(300 MHz, CD3CN): δ ϭ 8.83 (br s, 1 H, 3Ј-H), 8.74 (d, J ϭ 8.2 Hz,
1 H, 3-H), 8.31 (d, J ϭ 8.5 Hz, 2 H), 8.18–8.02 (m, 5 H), 7.98–7.83
(m, 6 H), 7.80 (d, J ϭ 1.8 Hz, 1 H, 5Ј-H), 7.66 (d, J ϭ 5.8 Hz, 1
H), 7.63 (d, J ϭ 8.0 Hz, 1 H), 7.53–7.43 (m, 5 H), 7.30 (d, J ϭ
8.0 Hz, 1 H), 7.17–7.06 (m, 4 H), 6.95 (m, 2 H), 6.83 (t, J ϭ 7.7 Hz,
1 H), 6.76 (t, J ϭ 7.8 Hz, 2 H), 6.65 (v br s, 2 H), 6.57 (t, J ϭ
7.6 Hz, 1 H), 6.37 (t, J ϭ 7.4 Hz, 1 H), 5.96 (d, J ϭ 7.7 Hz, 1 H),
5.58 (d, J ϭ 7.5 Hz, 1 H), 4.07 (t, 2 H, OCH2), 1.81 (m, 2 H,
OCH2CH2), 1.45–1.28 [m, 18 H, (CH2)9], 0.89 (t, 3 H, CH3). –
C70H64F6IrN4O5P (1378): calcd. C 60.99, H 4.68, N 4.06; found C
60.56, H 4.57, N 4.27.
[(ppy)2Ir(L-1)][PF6] (1): Yield: 65%, brown powder. – M.p. (DSC)
187 °C. – IR (KBr): ν˜ ϭ 842 cm–1 (PF) cm–1. – UV/Vis (acetonitr-
1
ile): λmax (log ε) ϭ 271 nm (4.64), 315sh (4.52), 383sh (4.02). – H
NMR (300 MHz, CD3CN): δ ϭ 8.88 (d, J ϭ 8.2 Hz, 1 H, 3-H),
8.83 (br s, 1 H, 3Ј-H), 8.19 (br t, 1 H, 4-H), 7.92 (d, J ϭ 8.6 Hz, 2
H, a-H), 7.81–7.69 (m, 6 H), 7.54 (br s, 1 H, 5Ј-H), 7.48 (d, J ϭ
7.5 Hz, 1 H), 7.31 (br m, 1 H, 5-H), 7.20 (d, J ϭ 7.6 Hz, 1 H),
7.10–7.05 (m, 3 H), 6.95–6.88 (m, 2 H), 6.81–6.70 (m, 3 H), 6.59–
6.54 (m, 2 H), 6.36 (br t, 1 H), 5.93 (d, J ϭ 7.5 Hz, 1 H), 5.57 (d,
J ϭ 7.5 Hz, 1 H), 4.03 (t, 2 H, OCH2), 1.80 (m, 2 H, OCH2CH2),
1.46–1.27 (m, 18 H, (CH2)9), 0.88 (t, 3 H, CH3). – C56H56F6IrN4OP
(1138): calcd. C 59.09, H 4.92, N 4.92; found C 58.72, H 5.23,
N 5.10.
Crystal Structure Determination: Diffraction data for complex 4
were collected on a Siemens (Bruker) SMART area detector dif-
fractometer by using graphite-monochromated Mo-Kα radiation
˚
(λ ϭ 0.71073 A) with the ω-2θ method (T ϭ 163 K). Data were
corrected for absorption (SADABS)[21] and Lorentz-polarization
effects. The structure was solved by direct methods using SHELXS-
97[22] and refined by full-matrix least-squares on F2 (SHELXL-
97).[22] Crystal data and structure refinements parameters are given
in Table 2. All nonhydrogen atoms were refined anisotropically. Hy-
drogen atoms were placed in calculated positions with fixed contri-
[(ppy)2Ir(L-2)][PF6] (2): Yield (after chromatography on silica gel
with CH2Cl2/5% MeOH as eluent): 24%, orange-brown powder. –
IR (KBr): ν˜ ϭ 843 cm–1 (PF). – UV/Vis (acetonitrile): λmax (log
ε) ϭ 272 nm (4.63), 314sh (4.49), 377sh (4.01). – 1H NMR
(CDCl3): δ ϭ 8.86 (d, J ϭ 7.9 Hz, 1 H, 3-H), 8.81 (d, J ϭ 2.0 Hz,
1 H, 3Ј-H), 8.17 (br t, 1 H, 4-H), 7.91 (d, J ϭ 8.8 Hz, 2 H, a-H),
7.85–7.67 (m, 6 H), 7.54 (br s, 1 H, 5Ј-H), 7.47 (d, J ϭ 7.0 Hz, 1
H), 7.30 (br m, 1 H, 5-H), 7.19 (d, J ϭ 7.0 Hz, 1 H), 7.07–7.04 (m,
3 H), 6.94–6.87 (m, 2 H), 6.80–6.70 (m, 3 H), 6.58–6.53 (m, 2 H),
6.35 (br t, 1 H), 5.92 (d, J ϭ 7.9 Hz, 1 H), 5.57 (d, J ϭ 7.9 Hz, 1
H), 4.01 (t, 2 H, OCH2), 1.79 (m, 2 H, OCH2CH2), 1.45–1.25 [m, 30
H, (CH2)15], 0.87 (t, 3 H, CH3). – C62H68F6IrN4OP (1222): calcd. C
60.92, H 5.61, N 4.58; found C 61.08, H 5.78, N 4.34.
Table 2. Crystal data, data collection parameters, solution and re-
finement for complex 4
Empirical formula
C64H52F6IrN4O5P
Formula weight
Crystal system
Space group
1294
monoclinic
P21/c
˚
a [A]
22.037(11)
˚
b [A]
34.821(22)
˚
[(ppy)2Ir(L-3)][PF6] (3): Yield: 81%, orange powder. – IR (KBr):
ν˜ ϭ 1716 cm–1 (CO), 842 (PF). – UV/Vis (acetonitrile): λmax (log
ε) ϭ 270 nm (4.44), 317sh (4.08), 386sh (3.57). – 1H NMR
(300 MHz, CD3CN): δ ϭ 8.82 (d, J ϭ 2.0 Hz, 1 H, 3Ј-H), 8.74 (d,
J ϭ 7.8 Hz, 1 H, 3-H), 8.20 (d, J ϭ 8.9 Hz, 2 H, b-H), 8.16 (t, J ϭ
7.8 Hz, 1 H, 4-H), 8.08 (d, J ϭ 8.9 Hz, 2 H, a-H), 7.96–7.89 (m, 4
H), 7.84 (d, J ϭ 6.0 Hz, 2 H), 7.79 (d, J ϭ 2.0 Hz, 1 H, 5Ј-H), 7.69
(d, J ϭ 5.9 Hz, 1 H), 7.61 (d, J ϭ 7.8 Hz, 1 H), 7.13–7.07 (m, 2
H), 6.98–6.92 (m, 2 H), 6.82 (t, J ϭ 7.0 Hz, 1 H), 6.77 (t, J ϭ
7.8 Hz, 2 H), 6.65 (br s, 2 H), 6.57 (t, J ϭ 7.0 Hz, 1 H), 6.37 (d,
J ϭ 7.4 Hz, 1 H), 5.96 (d, J ϭ 7.0 Hz, 1 H), 5.57 (d, J ϭ 7.0 Hz,
1 H), 5.45 (d, J ϭ 4.9 Hz, 1 H, chol.), 4.81 (m, 1 H, chol.), 2.5–0.7
(m, 43 H, chol.). – C72H76F6IrN4O2P (1366): calcd. C 63.28, H
5.61, N 4.10; found C 63.02, H 5.62, N 4.12.
c [A]
13.987(6)
α [°]
β [°]
γ [°]
90
90.38(4)
90
3
˚
V [A ]
10733(10)
Z
8
dcalcd. [g cm–3]
1.602
Crystal size [mm]
0.19 ϫ 0.15 ϫ 0.08
µ [mm–1]
2.596
Transmission (min/max)
2θ range [°]
0.701/0.928
3.0–50
Index range (h, k, l)
Reflections collected
Independent reflections
Observed reflections [I Ͼ 2σ(I)]
Parameters
–26 26, –41 41, –16 16
93561
18890
11149
1368
Final R indices
R indices (all data)
Goodness-of-fit on F2
R1 ϭ 0.0903, wR2 ϭ 0.1631
R1 ϭ 0.1569, wR2 ϭ 0.1760
1.562
[(ppy)2Ir(L-4)][PF6] (4): Yield: 80%, bright yellow powder. – M.p.
(DSC) 288 °C. – IR (KBr): ν˜ ϭ 1740, 1733 cm–1 (CO), 840 (PF). –
1042
Eur. J. Inorg. Chem. 2000, 1039Ϫ1043

Metal-Containing Amphiphiles
FULL PAPER
[10]
[11]
[12]
2
˚
F. Neve, A. Crispini, S. Campagna, Inorg. Chem. 1997, 36,
butions (U ϭ 0.08 A ). The two sets of C atoms [C(33) through
6150–6156.
C(38)] and [C(97) through C(102)] have been refined as rigid regu-
lar hexagons with default C–C bond lengths of 1.39 A.
F. Neve, M. Ghedini, O. Francescangeli, S. Campagna, Liq.
Cryst. 1998, 24, 673–680.
F. Kröhnke, Synthesis 1976, 1–24.
˚
Crystallographic data (excluding structure factors) for the structure
included in this paper have been deposited with the Cambridge
Crystallographic Data Centre as supplementary publication no.
CCDC-112438. Copies of the data can be obtained free of charge
on application to CCDC, 12 Union Road, Cambridge CB2 1EZ,
UK [Fax: (internat.) ϩ 44-1223/336-033; Email: deposit@ccdc.ca-
m.ac.uk].
[13] [13a]
Y. Ohsawa, S. Sprouse, K. A. King, M. K. De Armond,
K. W. Hanck, R. J. Watts, J. Phys. Chem. 1987, 91, 1047–
[13b]
1054. –
J. H. van Diemen, J. G. Haasnoot, R. Hage, E.
Müller, J. Reedijk, Inorg. Chim. Acta 1991, 181, 245–251. – [13c]
P. Didier, L. Ortmans, A. Kirsch-De Mesmaeker, R. J. Watts,
Inorg. Chem. 1993, 32, 5239–5245. – [13d] G. Calogero, G. Giuf-
frida, S. Serroni, V. Ricevuto, S. Campagna, Inorg. Chem. 1995,
34, 541–545.
[14]
[15]
J. H. van Diemen, R. Hage, H. E. B. Lempers, J. Reedijk, J. G.
Vos, L. De Cola, F. Barigelletti, V. Balzani, Inorg. Chem. 1992,
31, 3518–3522. – S. Serroni, A. Juris, S. Campagna, M. Venturi,
G. Denti, V. Balzani, J. Am. Chem. Soc. 1994, 116, 9086–9091.
M. Maestri, V. Balzani, C. Deuschel-Cornioley, A. von Zelew-
sky, Adv. Photochem. 1992, 17, 1–68.
Acknowledgments
Financial support from the Italian Ministero dellЈUniversita e della
Ricerca Scientifica e Tecnologica (MURST) and Consiglio Nazion-
ale delle Ricerche (CNR) is gratefully acknowledged. The authors
are also grateful to Jonathan Charmant and Professor G. A. Orpen
(University of Bristol) and to Professor P. Dapporto (University of
Florence) for X-ray data collection and helpful comments.
`
[16] [16a]
S. Sprouse, K. A. King, P. J. Spellane, R. J. Watts, J. Am.
[16b]
Chem. Soc. 1984, 106, 6647–6653. –
K. A. King, R. J.
[16c]
Watts, J. Am. Chem. Soc. 1987, 109, 1589–1590. –
F. O.
Garces, K. A. King, R. J. Watts, Inorg. Chem. 1988, 27, 3464–
3471. – [16d] B. Schmid, F. O. Garces, R. J. Watts, Inorg. Chem.
1994, 33, 9–14.
[1]
F. Vögtle, Supramolecular Chemistry, Wiley, Chichester, UK,
1991; J. M. Lehn, Supramolecular Chemistry: Concepts and Per-
[17]
[18]
[19]
[20]
[21]
[22]
M. G. Colombo, T. C. Brunold, T. Riedner, H. U. Güdel, M.
Förtsch, H.-B. Bürgi, Inorg. Chem. 1994, 33, 545–550.
F. O. Garces, K. Dedeian, N. L. Keder, R. J. Watts, Acta Crys-
tallogr. 1993, C49, 1117–1120.
R. Urban, R. Kramer, S. Mihan, K. Polborn, B. Wagner, W.
Beck, J. Organomet. Chem. 1996, 517, 191–200.
F. Neve, A. Crispini, S. Campagna, S. Serroni, Inorg. Chem.
1999, 38, 2250–2258.
spectives, VCH, Weinheim, 1995.
[2]
J.-H. Fuhrhop, J. Köning, Membranes and Molecular Assem-
blies: the Synkinetic Approach, The Royal Society of Chemistry,
Cambridge, 1994.
[3]
V. W.-W. Yam, V. C.-Y. Lau, K.-Z. Wang, K.-K. Cheung, J.
Mater. Chem. 1998, 8, 89–97.
[4]
H. Masui, R. W. Murray, Inorg. Chem. 1997, 36, 5118–5126.
[5]
I. A. Fallis, P. C. Griffiths, D. E. Hibbs, M. B. Hursthouse, A.
L. Winnington, Chem. Commun. 1998, 665–666.
G. M. Sheldrick, SADABS, Program for Empirical Absorption
Correction, Universität Göttingen, 1997.
[6]
F. Neve, M. Ghedini, G. De Munno, A.-M. Levelut, Chem.
Mater. 1995, 7, 688–693.
G. M. Sheldrick, SHELXL-97, Program for Crystal Structure
[7]
F. Neve, Adv. Mater. 1996, 8, 277–289.
Refinement, Universität Göttingen, 1997; SHELXS-97, Pro-
[8]
J. D. Holbrey, G. J. T. Tiddy, D. W. Bruce, J. Chem. Soc., Dalton
gram for Crystal Structure Solution, Universität Göttingen,
Trans. 1995, 1769–1774.
1997.
[9]
F. Neve, M. Ghedini, A. Crispini, Chem. Commun. 1996,
Received October 15, 1999
[I99364]
2463–2464.
Eur. J. Inorg. Chem. 2000, 1039Ϫ1043
1043