Amphiphilic dendrimers with heteroleptic bis([2,2′:6′,2″] terpyridine)-ruthenium(II) cores

Article abstract of DOI:10.1002/hlca.200490262

A new series of dendrimers was assembled through formation of homo- and heteroleptic Ru^II complexes with [2,2′:6′,2″] terpyridine ligands bearing hydrophilic and hydrophobic dendrons, with the aim to develop amphiphilic vectors for potential us

Full text of DOI:10.1002/hlca.200490262

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Amphiphilic Dendrimers with Heteroleptic Bis([2,2':6',2'']terpyridine)-
Ruthenium(II) Cores
by Derk Joestera), Volker Gramlichb), and FranÁois Diederich*a)
a) Laboratorium f¸r Organische Chemie, ETH-Hˆnggerberg, CH-8093Z¸rich
(e-mail: diederich@org.chem.ethz.ch)
b) Laboratorium f¸r Kristallographie, ETH-Zentrum, Sonneggstrasse 5, CH-8092 Z¸rich
A new series of dendrimers was assembled through formation of homo- and heteroleptic RuII complexes
with [2,2':6',2'']terpyridine ligands bearing hydrophilic and hydrophobic dendrons, with the aim to develop
amphiphilic vectors for potential use in gene delivery (Scheme 1). The synthesis started with the preparation of
the 4'-(3,5-dihalo-4-methoxyphenyl)-[2,2':6',2'']terpyridine ligands 1a,b via the Krˆhnke pyridine synthesis
(Scheme 2), followed by attachment of dendrons 10a 10f (Fig. 2) by Sonogashira cross-coupling to give the
dendritic ligands 11 16 (Schemes 3 and 4). Ligands were subsequently introduced into the coordination sphere
of RuIII to give the stable intermediates [Ru(11)Cl3] (24; Scheme 7) and [Ru(14)Cl3] (27; Scheme 8). These were
transformed under reductive conditions into the heteroleptic complexes [Ru(11)(13)](PF6)2 (25) and
[Ru(13)(14)](PF6)2 (29). Removal of the (tert-butoxy)carbonyl (Boc) protecting groups in 25 and 29 then
gave the desired amphiphilic dendrimers 26 (Scheme 7) and 30 (Scheme 8) with branchings of generations 0 and
1. Complex formation was analyzed by high-resolution matrix-assisted laser-desorption-ionization Fourier-
transform ion-cyclotron-resonance mass spectrometry (HR-MALDI-FT-ICR-MS), which provided spectra
featuring unique fragment-ion series and perfectly resolved isotope distribution patterns (Figs. 4 and 5). The
preparation of homo- and heteroleptic complexes with terpyridine ligands bearing generation-2 dendrons failed
due to steric hindrance by the bulky wedges.
1. Introduction. Dendrimers are well-known carriers of structure and function in a
wide variety of applications (for recent monographs and reviews, see [1]). Dendrons
have been shown to create specific microenvironments and to tune in a unique way
binding and reactivity properties of functional cores in dendritic enzyme mimics [2][3].
Self-assembly properties [4] are particularly enhanced in amphiphilic dendrimers that
are characterized by rich structural diversity including unimolecular micelles [5],
dendritic block copolymers [6], globular amphiphiles with fullerene cores [7], and
mesophase-forming tapered dendrons [8]. Dendritic self-assembly has recently been
used to generate novel vectors for gene transfection [9][10].
Another efficient route towards large supramolecular assemblies is based on
transition-metal complexation; this approach has been successfully applied to the
construction of a rich variety of metallodendrimers [11]. In our program, targeting
novel dendritic amphiphiles for potential application as gene transfection agents [10],
we decided to use transition metal complexation as a versatile way to assemble
lipophilic and cationic dendritic wedges. Here, we report the synthesis and character-
ization of a series of homo- and heteroleptic complexes of RuII with dendritic
[2,2';6',2'']terpyridine ligands. For the preparation of the bisterpyridine RuII complexes,
we intended to apply the versatile protocols reported by Constable et al. [12] and
Sauvage and co-workers [13].
¹ 2004 Verlag Helvetica Chimica Acta AG, Z¸rich

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2. Results and Discussion. A modular approach was selected for the synthesis of
the targeted amphiphilic dendrimers, consisting in i) preparation of halogenated
[2,2';6',2'']terpyridine ligands 1a and 1b, ii) Sonogashira cross-coupling [14] with
dendron-functionalized arylacetylenes 2 to give the dendron-substituted terpyridines 3,
and iii) formation of the heteroleptic RuII complexes 4 (Scheme 1). The synthesis of
terpyridine ligands with different substitution patterns is well-documented [15].
Substitution at C(4') (for conventional numbering, see Scheme 1) is a particularly
convenient process [16]. Both Pd-catalyzed Sonogashira [17] and Suzuki cross-
couplings [18][19] have been used to introduce halogenated terpyridine moieties into
dendritic structures, without any problems arising from complexation of PdII to the
ligands [20].
Scheme 1. Synthetic Strategy Towards Amphiphilic Dendrimers with a Bisterpyridine RuII Core
2.1. Synthesis of the Halogenated Terpyridine Ligands. The preparation of
terpyridine derivatives 1a and 1b started from the 3,5-dihalogenated anisaldehydes

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5a and 5b, respectively [21] (Scheme 2). The desired ligands were subsequently
obtained by the Krˆhnke pyridine synthesis [22] (for other protocols for terpyridine
syntheses that were less successful in this work, see [15][23]). Carefully controlled
aldol condensation [15][24] of 5a or 5b with 2-acetylpyridine in EtOH provided enones
6a and 6b, respectively, in high yields. Maintaining the reaction temperature below 58
and with KOH as base proved critical for the success of the condensation [25]. The one-
pot conversion of 6a and 6b with pyridinium iodide 7 [26] provided the desired ligands
1a and 1b, respectively, without formation of any constitutionally isomeric [17c][27]
terpyridine side products.
Scheme 2. Synthesis of Dihalogenated and Diethynylated Terpyridine Ligands
a) 2-Acetylpyridine, KOH, EtOH, À 108 ! 208, 18 h; 83 % (6a), 86% (6b). b) NH4OAc, AcOH, 120 1608,
16 24 h; 29% (1a), 64% (1b). c) From 1a, (i-Pr)3SiÀCꢀCH, [Pd(PPh3)2Cl2], CuI, Bu4NBr, (i-Pr)2NH, THF,
608, 16 h; 90%. d) Bu4NF, wet THF, 208, 30 min; 90%.
The diiodo derivative 1b was recrystallized from MeCN to yield crystals suitable for
X-ray structure analysis (Fig. 1). The compound crystallizes in colorless prisms
≈
(triclinic unit cell; space group: P1; two pairs of conformationally isomeric molecules
per unit cell). The three rings of the terpyridine moiety adopt a nearly planar
alignment, where N-atoms in adjacent rings are antiperiplanar with respect to each
other. Looking along the b-axis, the crystal packing revealed that neighboring stacks of
1b interlock in a herringbone pattern.
As an alternative to the route depicted in Scheme 1, we also explored an −inverted×
Sonogashira cross-coupling protocol starting from diethynylated terpyridine 8 and the
corresponding haloarylated dendrons. Under optimized conditions, cross-coupling of
poorly soluble 1a with (i-Pr)3SiÀCꢀCH gave a good yield of dialkynylated 9, which

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Fig. 1. a), b) ORTEP Plots: a) front and b) side views of 1b. Arbitrary numbering. Atomic displacement
parameters obtained at 293K are drawn at the 75% probability level. Shown is one of the two conformers of 1b,
with the dihedral angle C(3')ÀC(4')ÀC(10)ÀC(11) ˆ 39.28. In the second conformer (not shown), this dihedral
angle is 28.48. c) Crystal packing of 1b. The view along the b-axis shows the herringbone pattern of interlocking
stacks.
was readily deprotected to give 8 (Scheme 1). Although the coupling of iodoaryl-
substituted dendrons to 8 was successful, the reduced stability of the diethynyl
derivative and its propensity for oxidative Hay-type polymerizations led us to abandon
this approach.

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2.2. Attachment of the Dendrons to the Terpyridine Ligand. The synthesis of
dendrons 10a 10f (Fig. 2) has been reported in [10]. The Sonogashira cross-couplings
of diiodoterpyridine 1b (which was found to be far more reactive and more soluble than
the corresponding dibromo derivative 1a) with the smaller phenylethynylated, zeroth-
generation (G0) and first-generation (G1) dendrons 10a 10d went smoothly to
provide the dendritic ligands 11 14, respectively, in high yields (Scheme 3). In the case
of 13 and 14, GPC (gel-permeation chromatography) purification (Bio-Beads S-X1;
CH2Cl2) was required to remove small amounts of mono-coupled product. The high-
resolution matrix-assisted laser-desorption-ionization Fourier-transform ion-cyclotron-
resonance mass spectrum (HR-MALDI-FT-ICR, matrix: 2,5-dihydroxybenzoic acid
(DHB)) of 13 displayed a series of characteristic fragment ions, which contrasts the
lack of fragmentation in the spectrum of the ester analog 12. While the sodium adduct
‡
of the molecular ion of 13 appeared as a weak signal only (1534.7987 ([M ‡ Na] ,
‡
C84H109N11NaO15 ; calc. 1534.8002)), successive loss of C5H8O2 (−Boc×) fragments gave
rise to increasingly strong peaks separated by Dm/z ˆ 100.
Fig. 2. G1 and G2 dendrons 10a 10f with phenylacetylene termini [10]. Boc ˆ tert-butyloxycarbonyl.
The preparation and purification of the terpyridine ligands 15 and 16 (Scheme 4),
obtained by coupling the G2 dendrons 10e and 10f to 1b, proved to be a greater
challenge. While analytical GPC (THF) of 15 did not indicate any contamination after
preparative GPC purification (CH2Cl2), HR-MALDI-MS (DHB matrix) revealed the
‡
presence of traces of homo-coupled product 17 ([M ‡ Na] : m/z 3425). Further
purification was postponed since a reasonable difference in hydrodynamic radii
between 15 and 17 could only be expected after assembly to the metal complexes. As
‡
‡
with G1 ligand 13, the mass spectrum of 15 (3762.2500 ([M ‡ Na] , C192H307N29NaO45 ;
calc. 3762.2524)) displayed a series of characteristic fragment peaks resulting from
‡
successive loss of all eighteen Boc groups, with the [M À 18 Boc] ion becoming the
base peak. Similar fragmentation was also observed for homo-coupled 17. The cross-

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Scheme 3. Attachment of G1 Dendrons to the Terpyridine Ligand
a) [Pd(PPh3)2Cl2], CuI, Bu4NBr, (i-Pr)2NH, THF, 208, 16 h; 63 % (11); 84% (12); 72% (13); 54% (14).
coupling between 1b and the bulky dendron 10f to give 16 never went to completion,
even when using the more reactive [Pd(PPh3)4] as catalyst, and considerable amounts
‡
of homo-coupled 18 ([M ‡ Na] : m/z 5158 (100%)) were found in the product mixture.
Again, separation of 16 and 18 by GPC was not successful; only one sharp GPC peak
was recorded (THF). On the other hand, formation of the dendritic ligand 16 was
unambiguously demonstrated by MALDI-MS (matrix: DHB), which depicted the
‡
sodium complex of the molecular ion [M ‡ Na] as the second-most-intense peak at
m/z 5497 (58%). As for the corresponding G1 derivative 14, only very little
fragmentation was observed in the spectrum of 16.
2.3. Synthesis of the Homo- and Heteroleptic RuII Complexes. We have chosen
homo- and heteroleptic terpyridine complexes of RuII [12][13] to assemble the
dendrons for a variety of reasons. The 4'-substituted [2,2':6',2'']terpyridine ligands do
not give rise to chiral complexes as substituted 1,10-phenanthroline (phen) [28] and
3,3'-bipyridine (bipy) [29] ligands do, and the corresponding RuII (d6) complexes are
low-spin and thus diamagnetic. Heteroleptic RuII bisterpyridine complexes can be
prepared in two steps via intermediate RuIII complexes [12], while the conversion
leading to homoleptic complexes can be suppressed (Scheme 5). This is possible
because i) ligand exchange on RuIII is roughly 104 times slower than on RuII [30], ii) in
many cases the initially formed complex [Ru(L')Cl3] (L ˆ ligand) is insoluble in the
solvents used for its preparation (MeOH, EtOH) and thus precipitates from the
reaction mixture, and iii) an excess of RuCl3 ¥ H2O can be used as starting material in

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Scheme 4. Attachment of G2 Dendrons to the Terpyridine Ligand
a) [Pd(PPh3)2Cl2], CuI, Nu4NBr, (i-Pr)2NH, THF, 208, 16 h; 35% (15 and traces of 17); 35% (16 and 18).
Scheme 5. General Scheme for the Synthesis of Homoleptic and Heteroleptic Complexes of RuII
a) RuCl3 ¥ H2O (excess), EtOH, D. b) RuCl3 ¥ H2O (0.5 equiv.), N-ethylmorpholine, EtOH, D. c) L', N-
ethylmorpholine, EtOH, D. d) AgBF4, EtOH, acetone, D. e) L'', EtOH, D. X ˆ ClÀ, PF6À ; ac ˆ acetone.
the first step. Ru Complexes are also much more stable than the corresponding Fe
complexes. Exchange rates in homoleptic hexaqua complexes (which are closely
related to the exchange rates of other ligands) of FeII/FeIII are 108 times higher than

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those of the corresponding RuII/RuIII complexes [31]; thus homoleptic and heteroleptic
complexes will not equilibrate on relevant time scales.
When 1b was reacted with a ten-fold excess of RuCl3 ¥ H2O, the monoterpyridine
derivative [Ru(1b)Cl3] (19) was obtained in 95% yield, besides small amounts of the
homoleptic complex [Ru(1b)2]Cl2 (20) (Scheme 6). The latter was readily detected by
its intense red color and characteristic peaks in the mass spectra. Crystals of
[Ru(1b)Cl3], suitable for X-ray crystallography, were obtained when the crude mixture
was taken up in MeCN (Fig. 3). The brown prisms exhibited a monoclinic unit cell of
space group P2(1)/n. Two sets of four molecules in the unit cell adopt two different
conformations, differing primarily in the dihedral angle (1.78 and 38.98) between the
central terpyridine ring and the aryl ring attached to C(4').
With 0.5 equiv. of RuCl3 ¥ H2O in the presence of N-ethylmorpholine as reducing
agent, homoleptic [Ru(1b)2]Cl2 (20) was formed in one step in 51% yield. Prolonged
heating to reflux led to some degradation, although the starting material never
disappeared completely. This is probably due to inaccuracies in the weighing of
Scheme 6. Synthesis of Homoleptic Complexes 20 and 21
a) RuCl3 ¥ H2O (excess), EtOH, D, 3h; 95%. b) RuCl3 ¥ H2O (0.5 equiv.), N-ethylmorpholine, EtOH, D, 12 h;
51% (20). c) 1b, N-ethylmorpholine, EtOH, D, 12 h (yield of 20 not determined). d) AgBF4, EtOH, acetone,
758, 6 h. e) 1b, EtOH, D, 6 h; 88% (21, from 19).

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Fig. 3. ORTEP plot of [Ru(1b)2Cl3] (19). Arbitrary numbering; atomic displacement parameters obtained at
293K are drawn at the 50% probability level. The two conformers in the unit cell differ primarily in the dihedral
angle between the central terpyridine ring and the aryl ring attached to C(4'), which adopts a value of 1.78 in
conformer 1 (a) and 38.98 in conformer 2 (b).
hygroscopic RuCl3 ¥ H2O. The complex was conveniently isolated as [Ru(1b)2](PF6)2
(21) upon precipitation from a saturated aqueous solution of KPF6.
The formation of bis-terpyridine complex 21 was best carried out in two steps.
Addition of 1 equiv. of 1b and N-ethylmorpholine (as reducing agent) to monoterpyr-
idine derivative 19 and heating the EtOH solution for 12 h to reflux provided cleanly
[Ru(1b)2]Cl2 (20). To accelerate the ligand exchange, [Ru(1b)Cl3] was treated with
AgBF4 in acetone/EtOH mixtures to give [Ru(1b)(ac)3](BF4)3 (22) [13]. MALDI
Mass spectra (matrix: 2-{(2E)-3-[4-(tert-butyl)phenyl]-2-methylprop-2-enylidine}ma-
lononitrile (DCTB)) revealed that the coordination of the acetone ligands was not
stable enough to be detected. After filtration over Celite, 1b was added to the solution
of 22, and the conversion to the homoleptic complex 21, obtained after counterion
exchange (BFÀ4 ! PFÀ6 ), went smoothly and cleanly (88% yield from 19). In the HR-
‡
MALDI mass spectrum (DCTB) of 21, the [Ru(1b)2] ion appears as the parent ion
‡
‡
‡
(1282.764 ([M À 2 PF6] , C44H30I4N6O2Ru ; calc. 1282.7569)) besides strong peaks for
‡
[Ru(1b)2(PF6)] (45%) and [Ru(1b)2Cl] (62%). The latter peak is visible even after
repeated precipitation from aqueous KPF6 solution; therefore, we conclude that the
ClÀ ion is picked up from the matrix. A second group of weaker peaks at half the m/z
values originates from the same, but doubly charged species.
The homoleptic complex [Ru(11)2](PF6)2 (23) was readily prepared in 80% yield
and excellent purity by reacting terpyridine ligand 11 with 0.5 equiv. of RuCl3 ¥ H2O in
the presence of N-ethylmorpholine, followed by counterion exchange through
precipitation from a saturated aqueous solution of KPF6 (Scheme 7). The HR-MALDI

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Scheme 7. Synthesis of Homoleptic and Heteroleptic Complexes 23, 25, and 26
a) RuCl3 ¥ H2O (0.5 equiv.), N-ethylmorpholine, EtOH, D, 6 h; 80% (23). b) RuCl3 ¥ H2O (excess), EtOH, D,
6 h; 99%. c) 13, N-Ethylmorpholine, EtOH, D, 6 h; 66% (25). d) CF3COOH, CH2Cl2, 208, 2 h; 95%.

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‡
‡
mass spectra displayed essentially only the [Ru(11)2] ion (2025.0827 ([M À 2 PF6] ,
‡
C128H150N10O6Ru ; calc. 2025.0897) with the expected isotopic pattern and without any
visible fragmentation.
For the formation of heteroleptic complexes, the dendritic terpyridine ligand 11 was
reacted with an excess of RuCl3 ¥ H2O as described above (Scheme 6). Monoterpyridine
derivative [Ru(11)Cl3] (24) precipitated from the reaction mixture and was isolated by
filtration. Traces of the homoleptic complex were removed by washing with small
amounts of EtOH. However, even after heating for 6 h to reflux, remaining free ligand
11 was detected in the product mixture by MALDI-MS (DCTB). In addition to the
‡
‡
prominent ions [Ru(11)Cl3] (m/z 1170), [Ru(11)Cl2] (m/z 1134, 100%), and
‡
[Ru(11)Cl] (m/z 1098), the spectra revealed the presence of a peak at m/z 1056
(46%), which we tentatively assign to the NiII complex ion [Ni(11)Cl] . The source of
‡
the metal presumably is the spatula used in handling complex 24. Due to overlapping
‡
isotope patterns of the Ni complex and [Ru(11)] at m/z 1062, it was not possible to
unambiguously identify the metal, however.
The amphiphilic heteroleptic complex [Ru(11)(13)](PF6)2 (25) was obtained in
66% yield by treating 24 with 1 equiv. of dendritic ligand 13 in the presence of N-
ethylmorpholine. Similar to the free ligand 13, the complete series of fragment ions
corresponding to the successive loss of all six Boc groups was observed in the HR-
MALDI mass spectra (DCTB, Fig. 4). The dominant peak in the spectrum corresponds
‡
‡
‡
to the [Ru(11)(13)] ion (2575.2999 ([M À 2 PF6] , C148H184N16O18Ru ; calc.
2575.3054)). Gratifyingly, none of the alleged Ni impurity seen in the mass spectrum
of 24 could be detected.
Deprotection of 25 with CF3COOH in CH2Cl2 gave the final amphiphile 26 as the
trifluoroacetate salt (Scheme 7). The complex remained stable even under the strongly
acidic conditions, and no equilibration with the corresponding homoleptic compounds
occurred. The HR-MALDI mass spectra (DHB) depicted the hexa(primary amine)
ion obtained after loss of eight CF3COOH, as a strong peak at m/z 1974.9863(48%,
‡
‡
[M À 8 CF3COOH] , C118H136N16O6Ru ; calc. 1974.991) besides two prominent frag-
ment ions presumably originating from b-elimination of one (m/z 1958, 100%) and two
(m/z 1941, 63%) NH3 groups from the hydrophilic dendrons. These fragment ions were
also seen in the electrospray-ionization (ESI) MS in MeOH, which displayed strong
‡
peaks with corresponding isotope patterns for [MH À 8 CF3COOH] , [M ‡ 3 H À
8 CF3COOH]3‡, and [M ‡ 4 H À 8 CF3COOH]4‡. However, 1H- and 13C-NMR spectra
of 26 ((CD3)2SO) did not show any side products, which supports our assumption that
the fragmentation occurs during the transfer of the complex from the state of a salt into
the gas-phase ion. Similarly, the 19F-NMR spectra ((CD3)2SO) displayed only a single
resonance assigned to the CF3 group of the counterions. No residual PFÀ6 counterions
were detected.
When attempting the synthesis of the monoterpyridine complex [Ru(14)Cl3] (27;
Scheme 8) under the conditions outlined above, namely by refluxing 14 in EtOH or
MeOH with 10 equiv. of RuCl3 ¥ H2O, complex reaction mixtures resulted. Not even
trace amounts of the desired compound were formed, as judged by mass spectrometry.
This is presumably due to the insolubility of 14 in the solvents. RuCl3 ¥ H2O is not
soluble in CH2Cl2, CHCl3, or THF, which are all good solvents for the ligand, and the
ligand is not soluble in alcohols up to BuOH, or MeCN and H2O. In an attempt to solve

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Scheme 8. Synthesis of Homoleptic and Heteroleptic Complexes 28 30
a) RuCl3 ¥ H2O (0.5 equiv.), N-ethylmorpholine, MeOCH2CH2OH, D, 6 h; 61% (28). b) RuCl3 ¥ H2O (excess),
MeOCH2CH2OH, D, 6 h; 91%. c) 13, N-Ethylmorpholine, MeOCH2CH2OH, D, 6 h; 52% (29). d) CF3COOH,
CH2Cl2, 208, 2 h; 99%.

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this problem (similar solubility problems have been reported in the literature; see
[13][17d,f]), we turned to solvent mixtures. Mixtures of chlorinated solvents and
MeOH or ethyleneglycol, however, did not led to improvement, and, therefore, we
turned in a next attempt to high-boiling solvents. Eventually, 2-methoxyethanol (b.p.
124 1258) was found to solubilize both ligand and metal salt, which subsequently
enabled the synthesis of 27. However, separation and purification of the monoterpyr-
idine complex was now more complicated, since it could no longer be selectively
precipitated as was the case for the reactions in EtOH or MeOH. Purification by GPC
(Bio-Beads S-X1; CH2Cl2) was necessary to attain good purity. The HR-MALDI mass
spectra (DCTB) demonstrated the high purity of the complex, with expected peaks
‡
‡
appearing at m/z 2320 (22%, [Ru(14)Cl3 ‡ Na] ), 2261 (100%, [Ru(14)Cl2] ), and
‡
2226 (52%, [Ru(14)Cl] ). There is hardly any fragmentation detected, but an
unexpected peak at m/z 2081, 93mass units above the value expected for the free ligand
14, was observed. As in the case of [Ru(11)Cl3] (24), this peak was tentatively assigned
‡
to a Ni species ([Ni(14)Cl] ).
The direct formation of the homoleptic complex by reacting 14 with 0.5 equiv. of
RuCl3 ¥ H2O in the presence of N-ethylmorpholine proceeded smoothly in 2-methoxy-
ethanol. Counterion exchange by precipitation from a concentrated aqueous solution
of KPF6, followed by GPC purification (Bio-Beads S-X1; CH2Cl2), gave
[Ru(14)2](PF6)2 (28) in 61% yield. In the HR-MALDI mass spectra (DCTB), the
‡
[Ru(14)2] ion with the expected isotopic pattern appeared as the base peak at m/z
‡
‡
4279 (48%, [M À 2 PF6] , C264H410N22O18Ru ; calc. 4279.0882). A single contaminant
‡
ion at m/z 4238 (65%) was identified, which we tentatively assign to a [Ni(14)2] ion.
Preparation of the protected amphiphile 29 from 27 and 13 in the presence of
reducing agent proceeded cleanly in 2-methoxyethanol (Scheme 8). Above all, the
alleged Ni impurity did not carry through to this step. Accordingly, the MALDI mass
spectra (DCTB) after ion exchange (ClÀ ! PF6À ) depicted a pure compound, showing
‡
the [Ru(13)(14)] ion as the base peak at m/z 3704 (HR-MALDI-MS: 3702.3000
([M À 2 PFÀ6 ] , C216H314N22O24Ru ; calc. 3702.3064)). The characteristic successive loss
of the six Boc groups (Dm/z ˆ À100) accounts for all significant fragment ions (Fig. 5).
Cleavage of the Boc protecting groups with CF3COOH in CH2Cl2 then gave the
targeted amphiphile 30 with hydrophilic and hydrophobic branching of generation-1
(Scheme 8). The HR-MALDI mass spectra (in DHB or DCTB) showed the [MH À
‡
‡
‡
‡
8 CF3COOH] ion as the base peak at m/z 3102.9990 (C186H267N22O12Ru ; calc.
3102.9997), but only with very low intensity. The poor signal-to-noise ratio was also not
improved upon changing to ESI-MS.
Attempts to prepare the amphiphilic heteroleptic complex [Ru(15)(16)](PF6)2
with two G2 dendrons were less successful. Already the synthesis of the monoterpyr-
idine complex [Ru(16)Cl3] from RuCl3 ¥ H2O and 16 in 2-methoxyethanol, in which the
ligand is only poorly soluble, or in the better solvent triethyleneglycol monomethyl
ether failed (MALDI-MS). Note that impure 16 was used, with a major amount of
homo-coupled 18 present in the sample. This was, however, not expected to influence
the reactivity of the terpyridine ligand. Rather, it is the steric bulk of the dendritic
wedge that dramatically reduces the reactivity of 16.
We then tried to directly prepare the homoleptic complex [Ru(16)2]Cl2 by heating
to reflux a solution of 16, 0.5 equiv. of RuCl3 ¥ H2O, and reducing agent. Again, MALDI

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Fig. 5. HR-MALDI FT-ICR MS (DTCB) of [Ru(13)(14)](PF6)2 (29). The experimental isotope pattern (a) for
‡
the base peak, corresponding to [Ru(13)(14)] closely matches the calculated distribution (b). Marked peaks
*
(
) correspond to fragment ions resulting from successive loss of one or more Boc groups.
mass spectra did not indicate formation of any desired product. [Ru(Me2SO)4]Cl2 is a
more reactive RuII source than RuCl3 ¥ H2O because of the faster ligand exchange on
RuII and the more-labile Me2SO ligands [32]. Homoleptic complexes are usually
assembled quickly, as the reduction step is eliminated. However, this more reactive
starting material was also not effective in the preparation of [Ru(16)2]Cl2.
Similarly, the more-soluble G2 carbamate dendron 15 could not be transformed
into the corresponding complexes [Ru(15)Cl3] and [Ru(15)2]Cl2 by any one of the
methods described above. Apparently, the G2 dendrons are shielding the terpyridine
binding site efficiently. This could be due to collapse of the dendritic wedges onto the
terpyridine core or by simple aggregation. The complexes may possibly also be
destabilized by the steric bulk of the G2 dendrons. Alternatively, the many amide
functions in the dendrons may sequester the Ru ions, although the formation of higher-
molecular-weight complexes could not be detected by MALDI-MS.
In a final experiment, the highly soluble complex [Ru(1b)(ac)3](BF4)3 (22;
Scheme 6) was reacted with G2 dendron 16 in CH2Cl2 in the presence of reducing agent,
with the intention to introduce the carbamate wedges 10e by Sonogashira cross-
coupling later, after heteroleptic complex formation. However, this attempt to
circumvent the solubility problems associated with 15 also failed. At this point, the
synthesis of higher-generation dendrimers based on the heteroleptic RuII bis-
terpyridine core was abandoned.

Helvetica Chimica Acta Vol. 87 (2004)
2911
3. Conclusions. In an approach to prepare novel amphiphilic dendrimers as potential
vectors for gene transfection, lipophilic and hydrophilic dendrons of generations G0,
G1, and G2 were attached by Sonogashira cross-coupling to a novel diiodinated
terpyridine core. The assembly of stable homoleptic and heteroleptic RuII complexes
with terpyridine ligands carrying two G0 and G1 dendrons was successful, whereas the
assembly of such complexes from terpyridines functionalized with G2 dendrons failed.
The G2 dendrons apparently are shielding the terpyridine binding site efficiently,
thereby preventing it from undergoing ligand displacement; possibly, they may also be
destabilizing the complexes with their steric bulk. Steric hindrance could result from
collapse of the dendritic wedges onto the terpyridine core and/or from aggregation.
In light of the many reported syntheses of dendritic homo- and heteroleptic RuII
complexes of considerable size, it is hard to accept that this approach failed already at
the stage of the G2 dendrons. However, our systems differ substantially from those
previously described. In contrast to 15 and 16, most of the known ligand systems are
soluble in short-chain alcohols, which greatly facilitates complexation. When ligand
solubility was poor, soluble Ru complexes with one ligand already in place were used in
the assembly of homo- and heteroleptic complexes. The dendritic systems described by
Newkome et al. [17a, b] and Chow et al. [17c, d] differ by bearing long, flexible spacers
between the terpyridine unit and single dendrons. Only one other terpyridine ligand
with double dendron substitution for the formation of homoleptic RuII complexes has
been reported by Shirai and co-workers [25].
We thank the Swiss National Science Foundation for support of this work via the NCCR Basel (Nanoscale
Science). The help by Dr. C. Thilgen with the nomenclature is greatly acknowledged.
Experimental Part
»
General. Reagent-grade solvents (Fluka, J. T. Baker, or Riedel-de Haen) and chemicals (Aldrich, Acros,
Fluka, Lancaster, Sigma, ABCR, or STREM) were used without further purification, except where stated
otherwise. Syntheses of compounds 5a and 5b [21], 7 [26], and 10a 10f [10] are reported in the literature cited.
THF was freshly distilled from sodium benzophenone ketyl under N2. CH2Cl2 was freshly distilled from CaH2.
Solvents for chromatography were of technical quality and were distilled once prior to use. Evaporation in vacuo
was carried out at water aspirator pressure, drying at 10À2 Torr. Solvents and reagents for Sonogashira cross-
couplings were degassed by freeze-pump-thaw cycles for batches smaller than 10 ml. For reactions carried out at
larger scale, degassing was done by bubbling through a gentle stream of Ar, while sonicating, for 30 min. TLC:
SiO2 60 F254 from Merck, visualization by UV light (l ˆ 254 or 366 nm) or by staining with ninhydrin. Column
chromatography (CC): SiO2 60 (230 400 mesh, 40 63 mm) from Fluka, 0 0.4 Torr pressure. Gel-permeation
chromatography (GPC): anal. GPC: Shodex SEC columns with a Merck-Hitachi L-7360 column oven (408), L-
7100 pump (1 ml minÀ1 fixed flow rate), L-7400 variable wavelength UV detector (fixed at l ˆ 290 nm), and D-
2500 chromato-integrator or L-7500 autosampler; prep. GPC: Bio-Beads S-X1 (200 400 mesh) from Bio-Rad,
gravity-flow conditions, flow rate < 1 drop sÀ1. M.p.: B¸chi Smp 20 melting-point apparatus; uncorrected. IR
[cmÀ1]: Perkin-Elmer FT-IR 1600 spectrometer; the intensity of the bands is described as strong (s), medium
(m), or weak (w). NMR (1H, 13C, 19F): Varian Gemini 300 or Bruker AMX-500 instruments; spectra were
recorded at 298 K with solvent signal or TMS as reference. Mass spectrometry (MS): EI-MS: VG-TRIBRID
spectrometer at 70 eV; MALDI-TOF-MS: Bruker REFLEX spectrometer, DHB as matrix; HR-MALDI-FT-
ICR-MS: Ion Spec Ultima FT-ICR mass spectrometer, 2,5-dihydroxybenzoic acid (DHB) or 2-{(2E)-3-[4-(tert-
butyl)phenyl]-2-methylprop-2-enylidine}malononitrile (DCTB) as matrix. Elemental analyses were performed
by the Mikrolabor at the Laboratorium f¸r Organische Chemie at ETH Z¸rich on a LECO CHN/900
instrument.
(2E)-3-(3,5-Dibromo-4-methoxyphenyl)-1-(pyridin-2-yl)prop-2-en-1-one (6a). A mixture of 5a (2.31 g,
7.86 mmol) and 10% aq. KOH soln. (460 ml, 10 mol-%) in EtOH (100 ml) was sonicated under a stream of Ar for

2912
Helvetica Chimica Acta Vol. 87 (2004)
30 min. The mixture was cooled to 08, and a soln. of 2-acetylpyridine (881 ml, 952 mg, 7.86 mmol) in abs. EtOH
(20 ml) was added in four portions over 4 h while stirring under Ar. After 6 h, a yellowish microcrystalline
precipitate was collected by filtration. The mixture was stored at À 108 without stirring for 12 h. The precipitate
formed was collected by filtration, and the filtrate was concentrated in vacuo at 58 to one third of its volume. A
third crop of precipitate was collected by filtration and combined with the other precipitates to afford crude 6a
(2.57 g, 83%). Yellowish microcrystals. M.p. 1568. IR (KBr): 1673s, 1611s, 1582m, 1532m, 1474m, 1426m, 1394m,
1329m, 1264m, 1218m, 1032m, 994s, 796m, 740m. 1H-NMR (CDCl3, 300 MHz): 8.75 (ddd, J ˆ 5.0, 1.7, 0.8, 1 H);
8.21, 7.72 (AB, J ˆ 16.2, 2 H); 8.18 (ddd, J ˆ 7.8, 1.3, 1.2, 1 H); 7.88 (ddd, J ˆ 7.9, 7.7, 1.7, 1 H); 7.85 (s, 2 H); 7.51
(ddd, J ˆ 7.7, 5.0, 1.3, 1 H); 3.92 (s, 3 H). 13C-NMR (75 MHz, CDCl3): 189.221; 155.93; 154.10; 149.20; 141.14;
‡
137.37; 134.15; 132.87; 127.39; 123.25; 122.68; 118.91; 60.93. HR-MALDI-MS (DHB): 395.9220 (MH ,
C15H1279Br2NO2 ; calc. 395.9235).
‡
(2E)-3-(3,5-Diiodo-4-methoxyphenyl)-1-(pyridin-2-yl)prop-2-en-1-one (6b). A mixture of 5b (7.98 g,
20.58 mmol) and 10% aq. KOH soln. (1.15 ml, 2.06 mmol) in EtOH (160 ml) was sonicated under a stream
of Ar for 30 min. The mixture was cooled to 08, and a soln. of 2-acetylpyridine (2.31 ml, 2.49 g, 20.58 mmol) in
abs. EtOH (40 ml) was added in four portions over 4 h while stirring under Ar. After 6 h, a yellowish
microcrystalline precipitate was collected by filtration. The mixture was allowed to warm to 208, and stirring was
continued for 12 h. The formed precipitate was collected by filtration, and the filtrate was concentrated in vacuo
at 58 to one third of its volume. A third crop of precipitate was collected by filtration, and the precipitates were
combined to afford crude 6b (8.96 g, 86%). Yellowish microcrystals. M.p. 1688 (dec.). IR (KBr): 1671s, 1605s,
1
1582m, 1560m, 1522m, 1464m, 1419m, 1390m, 1324m, 1255m, 1217m, 1029m, 994m, 791m. H-NMR (CDCl3,
300 MHz): 8.76 (ddd, J ˆ 4.8, 1.5, 0.9, 1 H); 8.21 (m, 1 H); 8.20, 7.70 (AB, J ˆ 16.2, 2 H); 8.11 (s, 2 H); 7.90 (ddd,
J ˆ 7.8, 7.8, 1.8, 1 H); 7.52 (ddd, J ˆ 7.5, 4.7, 1.3, 1 H); 3.89 (s, 3 H). 13C-NMR (75 MHz, CDCl3): 188.87; 160.39;
153.82; 148.94; 140.56; 139.83; 137.86; 135.09; 127.19; 123.05; 122.18; 90.94; 60.88. HR-MALDI-MS (DHB):
‡
‡
491.8947 (MH , C15H12I2NO2 ; calc. 491.8961). Anal. calc. for C15H11I2NO2 (491.07): C 36.69, H 2.26, N 2.85, O
6.52; found: C 36.60, H 2.51, N 2.62, O 6.58.
4'-(3,5-Dibromo-4-methoxyphenyl)[2,2':6',2'']terpyridine (1a). A mixture of 6a (3.0 g, 7.56 mmol), 7 (3.2 g,
9.07 mmol), NH4OAc (30 g), and glacial AcOH (160 ml) was heated under Ar and vigorous mechanical stirring
to 1208 for 16 h, then to 1608 for 8 h. After cooling to 208, a brown precipitate was collected by filtration. The
filtrate was washed with H2O and dried. CC (300 g neutral Al2O3 (‡6% H2O); hexane/AcOEt 2 :1 ! 1:2),
followed by precipitation from a concentrated soln. in CH2Cl2 with hexane, afforded 1a (1.1 g, 29%). Tan solid.
M.p. 2358. IR (KBr): 1605m, 1584s, 1568m, 1527m, 1482m, 1467s, 1425m, 1411m, 1362m, 1358m, 1268m, 985m,
981m, 865m, 788m, 73 6m, 73 4s. 1H-NMR (CDCl3, 300 MHz): 8.75 (m, 2 H); 8.68 (m, 2 H); 8.66 (s, 2 H); 8.06 (s,
2 H); 7.91 (m, 2 H); 7.3 9 (m, 2 H); 3.97 (s, 3 H). 13C-NMR (75 MHz, CDCl3): 156.07; 155.68; 154.83; 149.05;
‡
147.21; 137.18; 137.01; 131.45; 124.17; 121.53; 118.81; 118.57; 60.83. HR-MALDI-MS (DHB): 495.9642 (MH ,
‡
‡
‡
C22H16Br2N3O ; calc. 495.9660); 517.9479 ([M ‡ Na] , C22H15Br2N3NaO ; calc. 517.9480).
4'-(3,5-Diiodo-4-methoxyphenyl)[2,2':6',2'']terpyridine (1b). A mixture of 6b (9.0 g, 18.3mmol), 7 (7.2 g,
21.96 mmol), NH4OAc (80 g), and glacial AcOH (160 ml) was heated under Ar and vigorous mechanical
stirring to 1608 for 16 h. After evaporation of AcOH in vacuo, the residue was treated with boiling MeCN
(1500 ml). Filtration, followed by CC (1000 g neutral Al2O3, act. IV (‡12% H2O); hexane ! hexane/AcOEt
1:1) and recrystallization (MeCN), afforded 1b (6.96 g, 64%). Tan needles. M.p. 2168. IR (KBr): 1583m, 1564m,
1518m, 1466m, 1403m, 1355m, 1256m, 1234m, 994m, 872m, 789s, 705m. 1H-NMR (CDCl3, 300 MHz): 8.76 (m,
2 H); 8.68 (m, 2 H); 8.65 (s, 2 H); 8.29 (s, 2 H); 7.91 (m, 2 H); 7.40 (m, 2 H); 3 .93 s(, 3 H). 13C-NMR (75 MHz,
CDCl3): 159.55; 156.15; 155.85; 149.16; 146.82; 138.50; 138.29; 137.0; 124.10; 121.45; 118.52; 91.03; 60.88. HR-
‡
‡
MALDI-MS (DHB): 591.9375 (MH , C22H16I2N3O ; calc. 591.9383). Anal. calc. for C22H15I2N3O (591.19): C
44.70, H 2.56, N 7.11, O 2.71; found: C 44.91, H 2.85, N 6.84, O 2.98.
4'-(4-Methoxy-3,5-bis{[tris(1-methylethyl)silyl]ethynyl}phenyl)[2,2':6',2'']terpyridine (9). A degassed sus-
pension of 1a (500 mg, 1.01 mmol), (i-Pr)3SiÀCꢀCH (1.35 ml, 1.1 g, 6.04 mmol), and (i-Pr)2NH (2.7 ml) in
freshly distilled THF (8 ml) was frozen with liquid N2. A previously prepared mixture of CuI (60 mg, 30 mol-
%), [Pd(PPh3)2Cl2] (106 mg, 15 mol-%), and Bu4NBr (64 mg, 20 mol-%), that was dried at 0.1 Torr for 1 h, was
added. The reaction vessel was evacuated and recharged with Ar three times before allowing it to warm to 208.
After stirring for 16 h under Ar at 608, sat. aq. NH4Cl soln. (50 ml) and CH2Cl2 (100 ml) were added. The org.
phase was washed with sat. aq. NH4Cl soln. (2Â) and H2O (1Â), dried (MgSO4), and concentrated. The residue
was taken up in CH2Cl2 and precipitated with MeOH to yield 9 (630 mg, 90%). Silver-gray plates. M.p. 1748. IR
1
(KBr): 3435m, 2941m, 1583m, 1467s, 1411m, 1367m, 1250m, 1072w, 1006s, 883s, 783m, 740m, 667m. H-NMR
(CDCl3, 300 MHz): 8.75 (m, 2 H); 8.68 (m, 2 H); 8.64 (s, 2 H); 7.89 (m, 2 H); 7.88 (s, 2 H); 7.3 7 (m, 2 H); 4.09 (s,
3H); 1.17 ( m, 42 H). 13C-NMR (75 MHz, CDCl3): 163.55; 156.12; 155.91; 149.16; 148.86; 136.98; 132.74; 123.99;

Helvetica Chimica Acta Vol. 87 (2004)
2913
‡
121.51; 118.73; 118.52; 109.96; 101.87; 96.49; 61.25; 18.46; 11.37. HR-MALDI-MS (DHB): 700.4134 (MH ,
‡
C44H58N3OSi2 ; calc. 700.4118).
4'-(3,5-Diethynyl-4-methoxyphenyl)[2,2':6',2'']-terpyridine (8). To a soln. of 9 (50 mg, 71.42 mmol) and one
drop of H2O in freshly distilled THF (5 ml), 1m Bu4NF in THF (290 ml, 290 mmol) was added. After stirring at 208
for 30 min, sat. aq. NH4Cl soln. (5 ml) and CH2Cl2 (25 ml) were added. The org. phase was washed with sat. aq.
NH4Cl soln. (2Â) and H2O (1Â), dried (MgSO4), and concentrated. The residue was taken up in CH2Cl2 (1 ml)
and precipitated with MeOH at À 208. After filtration, the mother liquor was concentrated to one half of its
volume and, a second precipitate was collected by filtration to yield 8 (25 mg, 90%). M.p. 2038 (dec.). IR (KBr):
3421m, 3310m, 3243m, 2922m, 2343w, 1602m, 1584s, 1563m, 1544m, 1469s, 1411s, 1372m, 1250m, 1074m, 876m,
1
787m, 73 4m. H-NMR (CDCl3, 300 MHz): 8.73 (m, 2 H); 8.67 (m, 2 H); 8.66 (s, 2 H); 8.01 (s, 2 H); 7.88 (m,
2 H); 7.3 6 (m, 2 H); 4.15 (s, 3 H); 3 .3 7s,(2 H). 13C-NMR (75 MHz, CDCl3): 163.55; 156.07; 155.91; 149.12;
147.92; 137.01; 133.81; 133.60; 124.04; 121.45; 118.41; 116.76; 82.52; 79.06; 61.60. HR-MALDI-MS (DHB):
‡
‡
388.1448 (MH , C26H18N3O ; calc. 388.1450).
N,N'-Didodecyl-4,4'-{[2-methoxy-5-(2,2':6',2''-terpyridin-4'-yl)benzene-1,3-diyl]bis(ethyne-2,1-diyl)}dibenz-
amide (11). A degassed soln. of 1b (20 mg, 33.8 mmol) and (i-Pr)2NH (1 ml) in freshly distilled THF (2 ml) was
frozen with liquid N2. A previously prepared mixture of CuI (2.0 mg, 32 mol-%), [Pd(PPh3)2Cl2] (4.75 mg,
20 mol-%), and Bu4NBr (2.1 mg, 20 mol-%), dried at 0.1 Torr for 1 h, was added. The reaction vessel was
evacuated and recharged with Ar (3Â) before allowing it to warm to 208. A degassed soln. of 10a (42.4 mg,
135.2 mmol) in freshly distilled THF (1 ml) was added slowly. After stirring for 16 h under Ar at 208, sat. aq.
NH4Cl soln. (5 ml) and CH2Cl2 (25 ml) were added. The org. phase was washed with sat. aq. NH4Cl soln. (2Â)
and H2O (1Â), dried (MgSO4), and concentrated. CC (Al2O3 (‡6% H2O); hexane/AcOEt 3:1 ! 1:1 ‡ 0.5%
Et3N) and GPC (Bio-Beads S-X1; THF then CH2Cl2) afforded 11 (32.5 mg, 63%). Yellowish solid. IR (KBr):
3315m, 2922s, 2849s, 1725w, 1633s, 1605m, 1583m, 1567m, 1534s, 1500m, 1468m, 1411m, 1378w, 1303m, 1262m,
1183w, 1081m, 1019m, 878m, 853m, 793m, 769w, 73 8w. 1H-NMR (500 MHz, CDCl3): 8.75 (ddd, J ˆ 4.8, 1.8, 0.9,
2 H); 8.71 (s, 2 H), 8.68 (ddd, J ˆ 7.9, 1.0, 1.0, 2 H); 8.05 (s, 2 H); 7.90 (ddd, J ˆ 7.7, 1.8, 2 H); 7.78, 7.63( AA'BB',
−J× ˆ 8.5, 8 H); 7.38 (ddd, J ˆ 7.5, 4.8, 1.2, 2 H); 6.17 (t, J ˆ 5.8, 2 H); 4.25 (s, 3H); 3.46 ( q, J ˆ 7.0, 4 H); 1.60 1.66
(br. m, 4 H); 1.2 1.4 (br. m, 36 H); 0.88 (t, J ˆ 7.0, 6 H). 13C-NMR (125 MHz, CDCl3): 166.73; 162.35; 156.04;
155.94; 149.09; 148.11; 137.01; 134.53; 133.94; 132.76; 131.74; 126.94; 126.10; 124.02; 121.48; 118.41; 117.51;
93.64; 87.10; 61.62; 40.23; 31.90; 29.66; 29.64; 29.62; 29.58; 29.55; 29.35; 29.34; 27.02; 22.67; 14.11. HR-MALDI-
‡
‡
MS (DHB): 962.5943( MH , C64H76N5O3 ; calc. 962.5948).
Hexa(tert-butyl) 3,3',3'',3''',3'''',3'''''-{[2-Methoxy-5-(2,2':6',2''-terpyridin-4'-yl)benzene-1,3-diyl]bis[(ethyne-
2,1-diyl)(benzene-4,1-diyl)(oxomethanediyl)(iminomethanetetrayl)]}hexapropanoate (12). According to the
protocol for the synthesis of 11, 1b (20 mg, 33.83 mmol) and (i-Pr)2NH (160 ml) in THF (1 ml) was reacted with
CuI (2.06 mg, 32 mol-%), [Pd(PPh3)2Cl2] (4.75 mg, 20 mol-%), Bu4NBr (2.14 mg, 20 mol-%), and 10b (110 mg,
203 mmol) in THF (2 ml). CC (20 g neutral Al2O3 (‡6% H2O); hexane/AcOEt 10 :1 ! 3:1) afforded 12 (40 mg,
84%). M.p. 1178. IR (KBr): 3374w, 2977m, 2932m, 1730s, 1665m, 1605m, 1584m, 1536m, 1500m, 1468m, 1367s,
1314m, 1256m, 1152s, 848m, 794m, 766w, 745w. 1H-NMR (CDCl3, 500 MHz): 8.76 (d, J ˆ 4.1, 2 H); 8.73( s, 2 H);
8.70 (d, J ˆ 7.9, 2 H); 8.07 (s, 2 H); 7.90 (dt, J ˆ 7.7, 1.7, 2 H); 7.83, 7.64 (AA'BB', −J× ˆ 8.2, 8 H); 7.38 (m, 2 H); 7.11
(s, 2 H); 4.26 (s, 3 H); 2.33, 2.15 (AA'BB', −J× ˆ 7.6, 24 H); 1.44 (s, 54 H). 13C-NMR (75 MHz, CDCl3): 173.21;
165.96; 162.36; 156.13; 156.03; 149.16; 148.20; 136.97; 134.78; 133.99; 132.71; 131.61; 127.09; 126.01; 124.01;
121.46; 118.44; 117.58; 93.78; 87.03; 80.88; 61.65; 57.95; 30.26; 29.97; 28.08. HR-MALDI- MS (DHB): 1422.7513
‡
‡
(MH , C84H104N5O15 ; calc. 1422.7529).
Hexa(tert-butyl) N,N',N'',N''',N'''',N'''''-([2-Methoxy-5-(2,2':6',2''-terpyridin-4'-yl)benzene-1,3-diyl]bis-
{[(ethyne-2,1-diyl)(benzene-4,1-diyl)(oxomethanediyl)(iminomethanetetrayl)]tris(ethane-2,1-diyl)})hexacarba-
mate (13). According to the protocol reported for the synthesis of 11, 1b (20 mg, 33.8 mmol) and (i-Pr)2NH
(1 ml) in THF (2 ml) were reacted with CuI (2.0 mg, 32 mol-%), [Pd(PPh3)2Cl2] (4.75 mg, 20 mol-%), Bu4NBr
(2.1 mg, 20 mol-%), and 10c (80 mg, 135.2 mmol) in THF (1 ml). CC (Al2O3 (‡6% H2O); hexane/AcOEt) and
GPC (Bio-Beads S-X1; CH2Cl2) afforded 13 (37 mg, 72%). Yellowish solid. M.p. 1368. IR (KBr): 3382s, 2976m,
2932m, 1693s, 1502s, 1366s, 1250s, 1170s, 854w, 792w. 1H-NMR (500 MHz, CDCl3): 8.70 (m, 2 H); 8.67 (s, 2 H);
8.63( d, J ˆ 8.0, 2 H); 8.01 (s, 2 H); 7.9, 7.57 (AA'BB', −J× ˆ 8.0, 10 H); 7.85 (dt, J ˆ 8.1, 1.8, 2 H); 7.33 (ddd, J ˆ 7.5,
4.8, 1.0, 2 H); 4.95 (s, 6 H), 4.21 (s, 3H); 3.15, 2.06 ( AA'BB', 24 H); 1.3 8 (s, 54 H). 13C-NMR (125 MHz, CDCl3):
166.66; 162.25; 156.12; 155.95; 155.81; 149.00; 148.02; 136.88; 134.68; 133.84; 132.46; 131.34; 127.36; 125.80;
123.91; 121.33; 118.26; 117.50; 93.78; 86.77; 79.25; 61.48; 56.97; 36.16; 35.98; 28.30. HR-MALDI-MS (DHB):
‡
‡
1534.7987 ([M ‡ Na] , C84H109N11NaO15 ; calc. 1534.8002).
N,N',N'',N''',N'''',N'''''-Hexadodecyl-3,3',3'',3''',3'''',3'''''-{[2-methoxy-5-(2,2':6',2''-terpyridin-4'-yl)benzene-
1,3-diyl]bis[(ethyne-2,1-diyl)(benzene-4,1-diyl)(oxomethanediyl)(iminomethanetetrayl)]}hexapropanamide

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Helvetica Chimica Acta Vol. 87 (2004)
(14). According to the protocol reported for the synthesis of 11, 1b (10 mg, 16.9 mmol) and (i-Pr)2NH (0.5 ml) in
THF (1 ml) were reacted with CuI (1.0 mg, 32 mol-%), [Pd(PPh3)2Cl2] (2.4 mg, 20 mol-%), Bu4NBr (1 mg,
20 mol-%), and 10d (60 mg, 135.2 mmol) in THF (0.5 ml). CC (Al2O3 (‡6% H2O; hexane/AcOEt) and GPC
(Bio-Beads S-X1; CH2Cl2) afforded 14 (19 mg, 54%). Yellowish solid. M.p. 1198. IR (KBr): 3297m, 2924s, 2852s,
1
1643s, 1547s, 1467m, 1377m, 1324m, 1296m, 1276m, 880w, 855w, 793w, 765w, 73 8w, 721w. H-NMR (500 MHz,
CDCl3): 8.75 (d, J ˆ 4.7, 2 H); 8.72 (s, 2 H); 8.68 (d, J ˆ 7.9, 2 H); 8.12 (s, 2 H); 8.05 (s, 2 H); 7.91, 7.63( AA'BB',
−J× ˆ 8.4, 8 H); 7.88 (m, 2 H); 7.3 7 (m, 2 H); 5.89 (t, J ˆ 5.5, 6 H); 4.25 (s, 3 H); 3.20 (q, J ˆ 6.7, 12 H); 2.31, 2.21
(AA'BB', −J× ˆ 7.3, 24 H); 1.46 (t, J ˆ 6.8, 12 H); 1.28 1.22 (m, 108 H); 0.86 (t, J ˆ 7.1, 18 H). 13C-NMR
(125 MHz, CDCl3): 173.15; 166.42; 162.33; 156.09; 156.01; 149.13; 148.12; 136.94; 134.51; 133.90; 133.72; 131.61;
127.29; 126.09; 123.98; 121.42; 118.37; 117.55; 93.81; 87.10; 61.55; 58.57; 39.77; 31.89; 31.86; 31.29; 29.65; 29.62;
29.60; 29.54; 29.34; 29.30; 26.94; 22.67; 14.09; one CH2 resonance around 29 ppm was not resolved. HR-
‡
‡
MALDI-MS (DHB): 2111.5809 ([M ‡ Na] , C132H205N11NaO9 ; calc. 2111.5819).
Octadeca(tert-butyl) N,NI,NII,NIII,NIV,NV,NVI,NVII,NVIII,NIX,NX,NXI,NXII,NXIII,NXIV,NXV,NXVI,NXVII-([2-Meth-
oxy-5-(2,2':6',2''-terpyridin-4'-yl)benzene-1,3-diyl]bis{(ethyne-2,1-diyl)(benzene-4,1-diyl)(oxomethanediyl)(imi-
nomethanetetrayl)tris[(1-oxopropane-3,1-diyl)(iminomethanetetrayl)tris(ethane-2,1-diyl)]})octadecacarbamate
(15). According to the protocol reported for the synthesis of 11, 1b (10 mg, 16.9 mmol) and (i-Pr)2NH (0.5 ml) in
THF (1 ml) were reacted with CuI (1.0 mg, 32 mol-%), [Pd(PPh3)2Cl2] (2.4 mg, 20 mol-%), Bu4NBr (1 mg,
20 mol-%), and 10e (115 mg, 135.2 mmol) in THF (0.5 ml). CC (SiO2; CH2Cl2/MeOH) and GPC (Bio-Beads S-
X1; CH2Cl2) afforded 15 (22 mg, 35%). Yellowish solid. M.p. 1568. IR (KBr): 3353m, 2978m, 1696s, 1529s,
1454m, 1392m, 1367s, 1274s, 1251s, 1170s, 867w, 780w. 1H-NMR (500 MHz, CDCl3): 8.75 (d, J ˆ 4.2, 2 H); 8.74 (s,
2 H); 8.71 (d, J ˆ 8.0, 2 H); 8.4 8.2 (br. m, 2 H); 8.08 (s, 2 H); 7.94, 7.62 (AA'BB', −J× ˆ 8.0, 8 H); 7.90 (t, J ˆ 8.3,
2 H); 7.40 (t, J ˆ 6.0, 2 H); 6.97 (br. m, 6 H); 4.81 (br. m, 18 H); 4.27 (s, 3H); 3.10, 1.91 ( AA'BB', 72 H); 2.34,
2.16 (AA'BB', 24 H); 1.3 9 (s, 162 H). 13C-NMR (125 MHz, CDCl3): 173.71; 165.97; 162.31; 156.12 (3 C); 149.10;
148.29; 143.42; 134.74; 133.93; 132.33; 131.48; 127.56; 125.79; 124.08; 121.52; 118.54; 117.66; 93.99; 86.87; 79.29;
‡
61.61; 58.62; 56.32; 35.85; 35.14; 33.04; 31.86; 28.44. HR-MALDI-MS (DHB): 3762.2500 ([M ‡ Na] ,
‡
C
192H307N29NaO45 ; calc. 3762.2524).
Bis[1,3-Diiodo-2-methoxy-5-(2,2':6',2''-terpyridin-4'-yl)benzene]ruthenium(II) Bis(hexafluorophosphate)
([Ru(1b)2](PF6)2) (21). A soln. of 1b (50 mg, 85 mmol) and RuCl3 ¥ H2O (84% RuCl3, 210 mg, 850 mmol) in
EtOH (25 ml) was heated for 3h to reflux under Ar. After cooling, the volume was reduced to one third. A
brownish precipitate was collected by filtration, washed with EtOH, and dried to give crude [Ru(1b)Cl3] (19)
(64 mg, 95%). A suspension of 19 ( g, 3 8mmol) and AgBF4 (22 mg, 113 mmol) in dry acetone (40 ml) and abs.
EtOH (10 ml) was heated to 758 for 6 h. The resulting soln. was filtered through Celite. EtOH (10 ml) was added
to the filtrate, and acetone was removed by evaporation in vacuo without heating. Compound 1b (22 mg,
38 mmol) was added to the soln. of crude 22, and the mixture was heated to reflux under Ar in the dark for 6 h.
The solvent was evaporated, and the residue was dissolved in a minimum volume of MeCN. This soln. was added
dropwise to sat. aq. KPF6 soln. The resulting red precipitate was washed with H2O and dried to give
[Ru(1b)2](PF6)2 (21) (53mg, 88%). Red solid. M.p. 256 8 (dec.). IR (KBr): 3432m, 1611w, 1520w, 1475w, 1462w,
1427w, 1395m, 1255w, 1030w, 993w, 844s, 786m, 752w, 707w, 557m. 1H-NMR (CDCl3, 500 MHz): 9.46 (s, 4 H);
9.13( d, J ˆ 8.2, 4 H); 8.90 (s, 4 H); 8.07 (ddd, J ˆ 7.9, 7.8, 1.4, 4 H); 7.52 (d, J ˆ 5.8, 4 H); 7.28 (ddd, J ˆ 7.4, 5.8, 1.4,
4 H); 3.33 (s, 6 H). 13C-NMR (125 MHz, CDCl3): 159.98; 157.83; 154.94; 152.04; 143.38; 138.42; 137.90; 135.69;
‡
‡
127.65; 124.90; 121.14; 92.55; 60.50. HR-MALDI-MS (DCTB): 1282.764 ([M À 2 PF6] , C44H30I4N6O2Ru ; calc.
1282.7569).
Bis(N,N'-Didodecyl-4,4'-{[2-methoxy-5-(2,2':6',2''-terpyridin-4'-yl)benzene-1,3- diyl]bis(ethyne-2,1-diyl)}di-
benzamide)ruthenium(II) Bis(hexafluorophosphate) (23). A soln. of 11 (50 mg, 52 mmol) and RuCl3 ¥ H2O
(84% RuCl3, 6 mg, 26 mmol) in N-ethylmorpholine (0.5 ml) and EtOH (2 ml) was heated for 6 h to reflux under
Ar. After cooling, the volume was reduced to one third. This soln. was then added dropwise to sat. aq. KPF6 soln.
The resulting red precipitate was washed with H2O and EtOH, and then dried. GPC (Bio-Beads S-X1; CH2Cl2)
gave 23 (48 mg, 80%). Red solid. M.p. 1738. IR (KBr): 3439w, 2958s, 2927s, 2856s, 1728s, 1641w, 1606w, 1537w,
1464m, 1404w, 1383w, 1275s, 1123m, 1072m, 846m, 788w, 742w, 557w. 1H-NMR (CDCl3, 500 MHz): 9.58 (s, 4 H);
9.17 (d, J ˆ 7.3, 4 H); 8.74 (s, 4 H); 8.59 (t, J ˆ 5.6, 4 H); 8.1 (t, J ˆ 7.8, 4 H); 7.98, 7.76 (AA'BB', −J× ˆ 8.5, 16 H);
7.56 (d, J ˆ 5.7, 4 H); 7.31 (t, J ˆ 7.9, 4 H); 4.33 (s, 6 H); 3.28 (q, J ˆ 6.6, 8 H); 1.54 (m, 8 H); 1.35 1.15 (m, 72 H);
0.86 (t, J ˆ 6.9, 12 H). 13C-NMR (125 MHz, CDCl3): 165.13; 162.59; 157.97; 155.11; 152.13; 144.52; 138.03;
134.98; 133.17; 131.87; 131.25; 127.71; 124.94; 124.35; 121.06; 117.03; 94.00; 86.63; 61.64; 31.25; 29.03; 29.02;
28.99; 28.97; 28.96; 28.74; 28.68; 26.44; 22.05; 13.91; one CH2 and one aromatic C-atom resonance were not
‡
‡
resolved. HR-MALDI-MS (DCTB): 2025.0827 ([M À 2 PF6] , C128H150N10O6Ru ; calc. 2025.0897).

Helvetica Chimica Acta Vol. 87 (2004)
2915
[(N,N'-Didodecyl-4,4'-{[2-methoxy-5-(2,2':6',2''-terpyridin-4'-yl)benzene-1,3- diyl]bis(ethyne-2,1-diyl)}di-
benzamide)[Hexa(tert-butyl) N,N',N'',N''',N'''',N'''''-([2-Methoxy-5-(2,2':6',2''-terpyridin-4'-yl)benzene-1,3-
diyl]bis{[(ethyne-2,1-diyl)(benzene-4,1-diyl)(oxomethanediyl)(iminomethanetetrayl)]tris(ethane-2,1-diyl)})hexa-
carbamate]ruthenium(II) Hexafluorophosphate (25). A suspension of 11 (50 mg, 52 mmol) and RuCl3 ¥ H2O
(84% RuCl3, 128 mg, 520 mmol) in abs. EtOH (10 ml) was heated to reflux under Ar for 6 h. After cooling, a
brown precipitate was collected by filtration, washed with H2O and EtOH, and dried to give crude 24 (60.8 mg,
99%). Complex 24 (60.8 mg, 51.5 mmol) and 13 (78 mg, 51 mmol) were subsequently suspended in abs. EtOH
(5 ml) and N-ethylmorpholine (500 ml). The mixture was heated to reflux under Ar for 6 h. The volume was then
reduced to one fifth. The red soln. was added dropwise to sat. aq. KPF6 soln. The resulting red precipitate was
collected by filtration and washed with EtOH and dilute aq. KPF6 soln. GPC (Bio-Beads S-X1; CH2Cl2) gave 25
(81 mg, 66%). Red transparent glass. M.p. 2068. IR (KBr): 3431m, 2925m, 2852m, 1696s, 1648s, 1533s, 1501s,
1404m, 1366m, 1250m, 1167s, 845s, 557m. 1H-NMR ((CD3)2SO, 500 MHz): 9.52 (s, 4 H); 9.10 (d, J ˆ 7.3, 4 H ) ;
8.69 (s, 4 H); 8.58 (t, J ˆ 5.8, 2 H); 8.06 (−t×, J ˆ 7.8, 4 H); 7.94, 7.90, 7.74, 7.72 (2 AA'BB', −J× ˆ 8.6, 16 H); 7.61 (br.
m, 2 H); 7.53( d, J ˆ 5.5, 4 H); 7.28 (−t×, J ˆ 6.3, 4 H); 6.72 (br. m, 6 H); 4.30 (s, 3H); 4.29 ( s, 3H); 3.26 (br. m,
4 H); 2.95 (br. m, 12 H); 1.91 (br. m, 12 H); 1.52 (br. m, 4 H); 1.3 4 (s, 54 H); 1.30 1.15 (m, 36 H); 0.83 (t, J ˆ 7.0,
6 H). 13C-NMR (125 MHz, (CD3)2SO): 165.81; 165.57; 162.81; 162.75; 158.21; 158.13; 155.82; 155.76; 155.25;
152.30 (br.); 144.83; 144.80; 138.25; 138.18; 136.01; 135.12; 135.08; 133.46 (br.); 132.22; 132.20; 131.48; 131.24;
128.20; 127.89; 125.18; 125.11; 124.59; 124.47; 121.35; 121.23; 117.24; 117.23; 94.26; 94.20; 86.82; 86.77; 77.79;
61.84; 61.81; 56.51; 35.46; 35.33; 34.41; 31.43; 29.17; 19.14; 29.11; 19.10; 28.88; 28.83; 28.40; 26.59; 22.23; 14.10;
‡
‡
three C-atom resonances missing. HR-MALDI-MS (DHB): 2575.2999 ([M À 2 PF6] , C148H184N16O18Ru ; calc.
2575.3054).
[(N,N'-Didodecyl-4,4'-{[2-methoxy-5-(2,2':6',2''-terpyridin-4'-yl)benzene-1,3-diyl]bis(ethyne-2,1-diyl)}di-
benzamide)[N,N',N'',N''',N'''',N'''''-([2-Methoxy-5-(2,2':6',2''-terpyridin-4'-yl)benzene-1,3-diyl]bis{[(ethyne-2,1-
diyl)(benzene-4,1-diyl)(oxomethanediyl)(iminomethanetetrayl)]tris(ethane-2,1-diyl)})hexaammonium]ruthe-
nium(II) Octakis(2,2,2-trifluoroacetate) (26). A soln. of 25 (50 mg, 17mmol) in 30% CF3COOH in CH2Cl2
(5 ml) was stirred under Ar at 208 for 2 h. After reducing the volume to one third in vacuo at 208, a red solid was
precipitated with Et2O (2 ml). The entire mixture was evaporated, re-suspended in Et2O, and sonicated. This
procedure was repeated twice, and final evaporation afforded 26 (48 mg, 95%). Red solid. M.p. 2278 (dec.). IR
(KBr): 3439s, 2920m, 2849m, 1676m, 1633m, 1536w, 1405w, 1298w, 1204m, 1134m, 83 6w, 799w, 722w. 1H-NMR
((CD3)2SO ‡ D2O, 300 MHz): 9.42 (s, 2 H); 9.41 (s, 2 H); 9.05 8.98 (m, 4 H); 8.63( s, 4 H); 8.05 7.99 (m, 4 H);
7.91, 7.88, 7.74, 7.73(2 AA'BB', −J× ˆ 8.3, 16 H); 7.52 (d, J ˆ 5.4, 2 H); 7.49 (d, J ˆ 5.6, 2 H); 7.29 7.24 (m, 4 H);
4.27 (s, 3H); 4.26 ( s, 3H); 3.24 ( t, J ˆ 6.9, 4 H); 2.80, 2.07 (AA'BB', 24 H); 1.50 (m, 4 H); 1.6 1.2 (m, 36 H); 0.81
‡
‡
(t, J ˆ 7.0, 6 H). HR-MALDI-MS (DHB): 1974.9863([ M À 8 CF3COOH] , C118H136N16O6Ru ; calc. 1974.991).
Bis(N,N',N'',N''',N'''',N'''''-Hexadodecyl-3,3',3'',3''',3'''',3'''''-{[2-methoxy-5-(2,2':6',2''-terpyridin-4'-yl)ben-
zene-1,3-diyl]bis[(ethyne-2,1-diyl)(benzene-4,1-diyl)(oxomethanediyl)(iminomethanetetrayl)]}hexapropanam-
ide)ruthenium(II) Bis(hexafluorophosphate) (28). A soln. of 14 (12 mg, 6 mmol) and RuCl3 ¥ H2O (84% RuCl3,
0.7 mg, 3 mmol) in dry 2-methoxyethanol (2 ml) was heated for 6 h to reflux under Ar. After cooling, the volume
was reduced to one third. This soln. was then added dropwise to sat. aq. KPF6 soln. The resulting red precipitate
was washed with H2O and EtOH, and then dried. GPC (Bio-Beads S-X1; CH2Cl2) gave 28 (8 mg, 61%). Red
solid. M.p. 1858. IR (KBr): 3426s, 2925s, 2853m, 1693s, 1649s, 1536s, 1466m, 1366m, 1251m, 1171m, 845m, 790w.
‡
‡
HR-MALDI-MS (DHB): 4279.0808 ([M À 2 PF6] , C264H410N22O18Ru ; calc. 4279.0882).
[(N,N',N'',N''',N'''',N'''''-Hexadodecyl-3,3',3'',3''',3'''',3'''''-{[2-methoxy-5-(2,2':6',2''-terpyridin-4'-yl)benzene-
1,3-diyl]bis[(ethyne-2,1-diyl)(benzene-4,1-diyl)(oxomethanediyl)(iminomethanetetrayl)]}hexapropanamide)-
[Hexa(tert-butyl)
N,N',N'',N''',N'''',N'''''-([2-Methoxy-5-(2,2':6',2''-terpyridin-4'-yl)benzene-1,3-diyl]bis-
{[(ethyne-2,1-diyl)(benzene-4,1-diyl)(oxomethanediyl)(iminomethanetetrayl)]tris(ethane-2,1-diyl)})hexacarba-
mate]ruthenium(II) Bis(hexafluorophosphate) (29). A suspension of 14 (30 mg, 14 mmol) and RuCl3 ¥ H2O
(84% RuCl3, 35 mg, 144 mmol) in dry 2-methoxyethanol (2 ml) was heated to reflux under Ar for 6 h. After
cooling, wet MeOH was added. A brown precipitate was formed, and it was collected by filtration, washed with
H2O and MeOH, and dried to give crude 27 (30 mg, 91%). Complex 27 (12.1 mg, 5.3 mmol) and 13 (8.1 mg,
5.3 mmol) were suspended in dry 2-methoxyethanol (2 ml) and N-ethylmorpholine (2 ml), and the mixture was
heated to reflux under Ar for 6 h. After cooling, CH2Cl2 (5 ml) and sat. aq. KPF6 soln. (10 ml) were added. The
phases were separated, and the aq. phase was extracted with CH2Cl2 (3Â). The combined org. phases were dried
(MgSO4) and evaporated. The resulting solid was taken up in CH2Cl2 and stirred with sat. aq. KPF6 soln. for 1 h.
The phases were separated, and the procedure was repeated twice. Evaporation and drying over P2O5
(0.01 Torr), followed by GPC (Bio-Beads S-X1; CH2Cl2), gave 29 (18 mg, 52%). Red solid. M.p. 2128. IR
(KBr): 3432m, 2925m, 2854w, 1697m, 1653m, 1534m, 1367w, 1256w, 1170m, 83 3s, 558m. 1H-NMR (CDCl3,

2916
Helvetica Chimica Acta Vol. 87 (2004)
500 MHz): 8.82 (br. m, 4 H); 8.53(br. m, 4 H); 8.17 (br. m, 4 H); 7.9 7.35 (m, 34 H); 7.11 (br. m, 4 H); 5.68 (br.
m, 6 H); 4.20 (br. m, 6 H); 3.17 (br. m, 12 H); 2.98 (br. m, 12 H); 2.1 1.8 (m, 3 6 H); 1.4 1.0 (m, 174 H); 0.69
(br., 18 H). 13C-NMR (125 MHz, CDCl3): 173.92; 167.60; 167.23; 162.91; 157.49; 156.60; 155.09; 146.88; 146.57;
138.08; 135.05; 134.74; 134.46; 132.85; 131.90; 131.29; 131.23; 127.19; 127.09; 126.39; 126.29; 125.70; 125.56;
124.91; 124.57; 121.14; 117.96; 96.00; 94.16; 86.35; 86.23; 79.15; 58.40; 56.95; 56.93; 39.38; 35.36; 35.24; 31.57;
31.01; 30.34; 29.31; 29.30; 29.28; 29.27; 29.22; 29.00; 28.90; 27.92; 26.63; 22.31; 13.60; eight C(sp2)-atom
‡
‡
resonances were not resolved. HR-MALDI-MS (DHB): 3702.3000 ([M À 2 PF6] , C216H314N22O24Ru ; calc.
3702.3064).
[(N,N',N'',N''',N'''',N'''''-Hexadodecyl-3,3',3'',3''',3'''',3'''''-{[2-methoxy-5-(2,2':6',2''-terpyridin-4'-yl)benzene-
1,3-diyl]bis[(ethyne-2,1-diyl)(benzene-4,1-diyl)(oxomethanediyl)(iminomethanetetrayl)]}hexapropanamide)-
[N,N'N'',N''',N'''',N'''''-([2-Methoxy-5-(2,2':6',2''-terpyridin-4'-yl)benzene-1,3-diyl]bis{[(ethyne-2,1-diyl)(ben-
zene-4,1-diyl)(oxomethanediyl)(iminomethanetetrayl)]tris(ethane-2,1-diyl)})hexaammonium]ruthenium(II)
Octakis(2,2,2-trifluoroacetate) (30). A soln. of 29 (10 mg, 3 mmol) in 30% CF3COOH in CH2Cl2 (1 ml) was
stirred under Ar at 208 for 1 h. After reducing the volume to one third in vacuo at 208, a red solid was
precipitated with Et2O (1 ml). The entire mixture was evaporated, re-suspended in Et2O, and sonicated. This
procedure was repeated twice, and evaporation provided 30 (10 mg, 99%). Red solid. M.p. 2258 (dec.). IR
(KBr): 3441s, 2924m, 2853m, 1712m, 1644s, 1537m, 1457w, 1261w, 1089m, 1022m, 803w. HR-MALDI-MS
‡
‡
(DHB): 3102.9990 ([MH À 8 CF3COOH] , C186H267N22O12Ru ; calc. 3102.9997).
X-RayCrystal Structures. Copies of the data can be obtained, free of charge, on application to CCDC, 12
Union Road, Cambridge CB21EZ, UK (fax: (‡44)1223-336-033; e-mail: deposit@ccdc.cam.ac.uk).
≈
Compound 1b. Crystal data at 293(2) K for C22H15I2N3O (Mr 591.17): triclinic, space group P1, Dc ˆ
1.908 g cmÀ3, Z ˆ 4 (2 conformers), a ˆ 5.016(4), b ˆ 18.761(10), c ˆ 23.66(2) ä, a ˆ 111.53(5), b ˆ (94.97(6),
g ˆ 92.11(6)8, Vˆ 2058(2) ä3, MoKa radiation, l ˆ 0.71073ä, linear crystal dimensions ca. 0.3  0.1  0.1 mm.
The structure was solved by direct methods (SHELXS 86) and refined by full-matrix least-squares analysis
(SHELXTL PLUS (VMS)). All heavy atoms were refined anisotropically, H-atoms isotropically; H-positions
are based on stereochemical considerations. Final R(F) ˆ 0.0576, wR(F2) ˆ 0.1789 for 506 parameters and 3012
reflections with I > 2s(I) and 1.78 < q < 20.048. Cambridge Crystallographic Data Centre Deposition No.
CCDC-245959.
Compound 19. Crystal data at 293(2) K for C22H15Cl3I2N3ORu ¥ 0.5 MeCN (Mr 819.12): monoclinic, space
group P2(1)/n, Dc ˆ 2.048 g cmÀ3, Z ˆ 8 (2 conformers), a ˆ 13.772(9), b ˆ 15.23(2), c ˆ 24.93(2) ä, b ˆ
97.87(6)8, Vˆ 5179(8) ä3, CuKa radiation, l ˆ 1.54178 ä, linear crystal dimensions ca. 0.08  0.04  0.04 mm.
The structure was solved by direct methods (SHELXS 86) and refined by full-matrix least-squares analysis
(SHELXTL PLUS (VMS)). All heavy atoms were refined anisotropically, H-atoms isotropically; H-positions
are based on stereochemical considerations. Final R(F) ˆ 0.0777, wR(F2) ˆ 0.192 for 604 parameters, 841
restraints, and 3979 reflections with I > 2s(I) and 3.41 < q < 50.008. Cambridge Crystallographic Data Centre
Deposition No. CCDC-245960.
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Received August 11, 2004