Light-induced geometrical changes in acyclic ruthenium(II) complexes and their ruthena-macrocyclic analogues

Article abstract of DOI:10.1021/ic700734q

The two ligands 1 (4′-(3-anisylphenyl)-2,2′;6′,2″- terpyridine) and 2 (2-mesityl-8-anisyl-1,10-phenanthroline) (Scheme 2) were synthesized and coordinated to ruthenium. The corresponding complexes Ru(1)(2)(L)ⁿ⁺, where L = Cl^-, CH₃CN, or C ₅H₅N, have been fully characterized. Notably, the hindering mesityl group of the phenanthroline ligand was shown to lie opposite to the monodentate ligand L both in solution and in the solid state. Upon irradiation in acetonitrile or pyridine, quantitative isomerization of the complex occurred, which consisted of a 90° rotation of the bidentate chelate. In the new isomers the mesityl group was shown to π stack to the coordinated monodentate ligand with the anisyl group of the phen (1,10-phenanthroline) lying on the other side of the ruthenium atom. The back reaction was performed by heating the photochemical isomers of the complexes in DMSO and exchanging the DMSO with chloride anion, acetonitrile, or pyridine. The stability of the ruthenium(II)-pyridine bond was used in order to inscribe the Ru(terpy)(phen) motif in a molecular ring. Functionalization of the ligands and subsequent cyclization reaction on the complex were performed on the two isomers of Ru(1)(2)(C₅H₅N)²⁺. Four macrocyclic complexes including the Ru(terpy)(phen)(py)ⁿ⁺ moiety were obtained and characterized. A (CH₂)₁₈ alkane chain or polyethylene glycol chain formed the flexible part of the ruthena-macrocycles. Upon visible light irradiation a dramatic geometrical changeover of the cyclic complex took place, which could be reversed thermally.

Full text of DOI:10.1021/ic700734q

Inorg. Chem. 2007, 46, 10520−10533
Light-Induced Geometrical Changes in Acyclic Ruthenium(II) Complexes
and Their Ruthena Macrocyclic Analogues
−
Sylvestre Bonnet, Jean-Paul Collin,* and Jean-Pierre Sauvage
Laboratoire de Chimie Organo-Mine´rale, UMR 7177 du CNRS, Institut Le Bel, UniVersite´ Louis
Pasteur, 4 rue Blaise Pascal, 67000 Strasbourg Cedex, France
Received April 18, 2007
The two ligands 1 (4
′
-(3-anisylphenyl)-2,2
′
;6
′
,2′′-terpyridine) and 2 (2-mesityl-8-anisyl-1,10-phenanthroline) (Scheme
Cl-,
2) were synthesized and coordinated to ruthenium. The corresponding complexes Ru(1)(2)(L)n+, where L
)
CH3CN, or C5H5N, have been fully characterized. Notably, the hindering mesityl group of the phenanthroline ligand
was shown to lie opposite to the monodentate ligand L both in solution and in the solid state. Upon irradiation in
acetonitrile or pyridine, quantitative isomerization of the complex occurred, which consisted of a 90
° rotation of the
bidentate chelate. In the new isomers the mesityl group was shown to stack to the coordinated monodentate
π
ligand with the anisyl group of the phen (1,10-phenanthroline) lying on the other side of the ruthenium atom. The
back reaction was performed by heating the photochemical isomers of the complexes in DMSO and exchanging
the DMSO with chloride anion, acetonitrile, or pyridine. The stability of the ruthenium(II)−pyridine bond was used
in order to inscribe the Ru(terpy)(phen) motif in a molecular ring. Functionalization of the ligands and subsequent
cyclization reaction on the complex were performed on the two isomers of Ru(1)(2)(C5H5N)2+. Four macrocyclic
+
complexes including the Ru(terpy)(phen)(py)n moiety were obtained and characterized. A (CH2)18 alkane chain or
polyethylene glycol chain formed the flexible part of the ruthena−macrocycles. Upon visible light irradiation a dramatic
geometrical changeover of the cyclic complex took place, which could be reversed thermally.
Introduction
past few years, a very distinct family of dynamic molecular
systems takes advantage of the dissociative character of
ligand-field states in Ru(diimine)32+ complexes.13-15 In these
compounds, one part of the system is set in motion by
photochemically expelling a given chelate, the reverse motion
being performed simply by heating the product of the
Control of discrete and large-amplitude motions via
various types of signals is a key feature for the development
of nanomechanical devices and information storage at the
molecular level.1-4 Photonic energy is particularly promising
since this input signal can be switched on and off fast and
readily on a very small place. Several molecular machines
have recently been reported which are set in motion by light
irradiation.5-12 Among the light-driven molecular machine
prototypes which have been described in the course of the
(8) Brouwer, A. M.; Frochot, C.; Gatti, F. G.; Leigh, D. A.; Mottier, L.;
Paolucci, F.; Roffia, S.; Wurpel, G. W. H. Science 2001, 291, 2124-
2128.
(9) Ashton, P. R.; Ballardini, R.; Balzani, V.; Credi, A.; Dress, K. R.;
Ishow, E.; Kleverlaan, C. J.; Kocian, O.; Preece, J. A.; Spencer, N.;
Stoddart, F. J.; Venturi, M.; Wenger, S. Chem. Eur. J. 2000, 6, 3558-
3574.
(10) Murakami, H.; Kawabuchi, A.; Kotoo, K.; Kunitake, M.; Nakashima,
N. J. Am. Chem. Soc. 1997, 119, 7605-7606.
(11) Eelkema, R.; Pollard, M. M.; Vicario, J.; Katsonis, N.; Serrano Ramon,
B.; Bastiaansen, C. W. M.; Broer, D. J.; Feringa, B. L. Nature 2006,
440, 163.
(12) Balzani, V.; Clemente-Le´on, M.; Credi, A.; Ferrer, B.; Venturi, M.;
Flood, A. H.; Stoddart, J. F. Proc. Natl. Acad. Sci. U.S.A. 2006, 103,
1178-1183.
(13) Collin, J.-P.; Laemmel, A.-C.; Sauvage, J.-P. New J. Chem. 2001, 25,
22-24.
(1) Balzani, V.; Venturi, M.; Credi, A. Molecular DeVices and Machines;
Wiley-VCH: Weinheim, 2003; p 494.
(2) Fabbrizzi, L.; Foti, F.; Patroni, S.; Pallavicini, P.; Taglietti, A. Angew.
Chem., Int. Ed. 2004, 43, 5073.
(3) Balzani, V.; Credi, A.; Raymo, F. M.; Stoddart, F. J. A. Angew. Chem.,
Int. Ed. 2000, 39, 3348-3391.
(4) Sauvage, J.-P. Molecular Machines and Motors; Springer: Berlin,
Heidelberg, 2001; Vol. 99.
(5) Ballardini, R.; Balzani, V.; Gandolfi, M.-T.; Prodi, L.; Venturi, M.;
Philp, D.; Ricketts, H. G.; Stoddart, F. J. Angew. Chem., Int. Ed. 1993,
32, 1301-1303.
(6) Livoreil, A.; Sauvage, J.-P.; Armaroli, N.; Balzani, V.; Flamigni, L.;
Ventura, B. J. Am. Chem. Soc. 1997, 119, 12114-12124.
(7) Armaroli, N.; Balzani, V.; Collin, J.-P.; Gavina, P.; Sauvage, J.-P.;
Ventura, B. J. Am. Chem. Soc. 1999, 121, 4397-4408.
(14) Pomeranc, D.; Jouvenot, D.; Chambron, J.-C.; Collin, J.-P.; Sauvage,
J.-P.; Heitz, V. Chem. Eur. J. 2003, 9, 4247-4254.
(15) Mobian, P.; Kern, J.-M.; Sauvage, J.-P. Angew. Chem., Int. Ed. 2004,
43, 2392-2395.
10520 Inorganic Chemistry, Vol. 46, No. 25, 2007
10.1021/ic700734q CCC: $37.00
© 2007 American Chemical Society
Published on Web 11/15/2007

Acyclic Ruthenium(II) Complexes
Scheme 1. Schematic View of the Two Ruthenium Isomer
Complexes Displaying the Reorganization of the Flexible Chain
Gathering the Ligands Terpyridine and Phenanthroline
Scheme 2. Synthesis of Terpyridine 1 and Phenanthroline 2
photochemical reaction so as to regenerate the original state.
Complexes of the [Ru(diimine)3]2+ family are particularly
well adapted to this approach. If distortion of the coordination
octahedron is sufficient to significantly decrease the ligand
field, which can be realized by using one or several sterically
hindering ligands, the strongly dissociative ligand-field state
(3d-d state) can be efficiently populated from the metal-to-
ligand charge-transfer (3MLCT) state to result in expulsion
of a given ligand. In a previously reported Ru(II) complex,
a p-phenylene bridge linking two phen chelates blocked the
coordination pattern of the complex during irradiations and
enabled precise control of the geometry of the molecules.16
In our quest to Ru(II)-containing macrocycles, we recently
studied the Ru(terpy)(phen)(L)2+ system, where L is a
monodentate ligand (terpy ) 2,2′;6′,2′′-terpyridine and phen
) 1,10-phenanthroline). This family of complexes allows
the complexation of a wide variety of ligands L that can be
photoexpelled upon light irradiation.17-19 As rings are
essential components of molecular machine prototypes and
metal-templated catenanes and rotaxanes, we describe in the
present report a new photoreactive system based on the Ru-
(terpy)(phen)(L)n+ moiety embedded in a ring. This approach
was not straightforward since the terpy fragment occupies
three meridional sites of the octahedral coordination sphere
and the phen chelate is orthogonal to the plane of the terpy.
An alkyl or a polyethylene glycol chain as linker between a
lateral position of the phen (3 position) and the para position
(4′) of the central pyridine nucleus can gather these two
fragments in a convenient way (Scheme 1).
performed on the complex was adopted. The ruthenium
precursor complexes should possess two chemically reactive
functions favorably disposed in space. Two anisyl groups
(as protected phenolic functions) have been introduced in
appropriate positions of the terpyridine and phenanthroline.
Use of a m-bromobenzaldehyde as precursor of the terpy-
ridine leads, after a “Suzuki coupling” reaction, to a
terpyridine displaying a first anchorage point for the linker.
Another anisyl group introduced in the 8 position of the
phenanthroline provides a second anchorage point without
perturbing the ability of the coordination site of the ligand.
Heteroleptic ruthenium complexes of the type Ru(terpy)-
(phen)(L)n+ lead to two possible isomers if the bidentate
ligand is unsymmetrical.21 In an attempt to circumvent this
difficulty a bulky mesityl group was introduced in the R
position of one nitrogen atom of the phen. Synthesis of the
ligands and the corresponding ruthenium complexes as well
as their photochemical reactivity will be described in the first
part of the article, while the second part will be devoted to
the design, synthesis, and properties of the macrocyclic
complexes incorporating the Ru(terpy)(phen)(L)n+ moiety.
Upon visible light irradiation, exchange of the monodentate
ligand and isomerization take place in the ruthenium acyclic
precursors, whereas additional dramatic contractions of the
linkers were observed in the macrocyclic complexes. These
photochemical reactions are generally thermally reversible
with retention of the coordination geometry. A preliminary
account of this work has been published recently.20
Synthesis of the Ligands and Their Corresponding
Acyclic Complexes. The synthesis of the terpyridine 1 and
phenanthroline 2 is shown in Scheme 2. Among the main
synthetic methods toward terpyridines,22,23 Kro¨hnke reaction
was preferred for the synthesis of terpyridine 1 due to the
mildness of the reaction conditions and simplicity of
purification. Chalcone 3 and pyridinium iodide 4 were
reacted in the presence of a nitrogen source (NH4OCOCH3)
to generate, after air oxidation, the central pyridine ring of
terpyridine 5, which precipitated in the reaction mixture. A
Results and Discussion
Since Ru(II) is kinetically inert, the so-called self-assembly
approach could not be used to synthesize the targeted
complexes and a strategy relying on organic chemistry
(16) Mobian, P.; Kern, J.-M.; Sauvage, J.-P. HelV. Chim. Acta 2003, 86,
4195-4213.
(17) Bonnet, S.; Collin, J.-P.; Gruber, N.; Sauvage, J.-P. J. Chem. Soc.,
Dalton Trans. 2003, 4654-4662.
(18) Bonnet, S.; Schofield, E. R.; Collin, J.-P.; Sauvage, J.-P. Inorg. Chem.
2004, 43, 8346-8354.
(19) Schofield, E. R.; Collin, J.-P.; Gruber, N.; Sauvage, J.-P. Chem.
Commun. 2003, 188-189.
(21) Laemmel, A.-C.; Collin, J.-P.; Sauvage, J.-P. C. R. Acad. Sci. Paris
2000, 3, 43-49.
(22) Heller, M.; Schubert, U. S. Eur. J. Org. Chem. 2003, 947-961.
(23) Thompson, A. M. W. C. Coord. Chem. ReV. 1997, 160, 1-52.
(20) Bonnet, S.; Collin, J.-P.; Sauvage, J.-P. Chem. Commun. 2005, 3195-
3197.
Inorganic Chemistry, Vol. 46, No. 25, 2007 10521

Bonnet et al.
+
+
Scheme 3. Synthesis of Ruthenium Complex 8th
Scheme 4. Thermal Ligand Substitution Reactions of 8th
Suzuki cross-coupling reaction24 between 4′-(3-bromophe-
nyl)-2,2′;6′,2′′-terpyridine (5) and commercially available
anisylboronic acid resulted in terpyridine 1.
Monobromination of 1,10-phenanthroline in the 3 position
needs harsh conditions and was performed as the first step.25
Although well described in the literature, this reaction was
very sensitive to the reaction conditions and poorly reproduc-
ible. Notably, 3,5-dibromophenanthroline was often found
as byproduct and difficult to remove by chromatography. A
published recrystallization procedure was used in order to
eliminate the dibrominated phenanthroline.26 A Suzuki cross-
coupling reaction between the monobrominated compound
and anisylboronic acid leads to 3-anisyl-1,10-phenanthroline
(6). Nucleophilic addition of lithiated derivatives, followed
by rearomatization by manganese dioxide, is a very efficient
method developed by Dietrich-Bu¨checker et al. for the
introduction of aryl substituents in the R position to the
nitrogen atom of polypyridine systems.27 In the case of
hindered derivatives like bromomesitylene, lithiation is
performed at room temperature with n-BuLi.28 Addition of
the mesityllithium solution to the dissymmetric phenanthro-
line 6 in ether or toluene afforded, after rearomatization, a
mixture of two regioisomers: 8-anisyl-2-mesityl-1,10-
phenanthroline (2) and 3-anisyl-2-mesityl-1,10-phenanthro-
line. Separation on acidic alumina enabled isolation of both
compounds in 26% and 19% yields, respectively.
The synthesis of the complex Ru(1)(2)(Cl)+ (8th+) is
depicted in Scheme 3. As will be discussed later, two series
of complexes have been obtained by either thermal or
photochemical reactions. The origin of each complex will
be mentioned by the abbreviations “th” and “photo”,
respectively, in lower index.
Coordination of terpyridine 1 on RuCl3‚xH2O was efficient
and enabled gram-scale preparation of Ru(1)Cl3 (7) as an
insoluble brown material. Coordination of phenanthroline 2
to complex 7 was limiting in terms of reaction scale. With
unhindered bidentate chelates like 2,2′-bipyridine or 1,10-
phenanthroline, Calvert’s conditions29 gave the corresponding
Ru(terpy)(N-N)(Cl)+ complex in 60-70% yield.17,18,30 In
the case of phenanthroline 2, metallic ruthenium and Ru-
(terpy)22+ were also produced in relatively high yields, which
limited the preparation of 8th in the 15-45% yield range.
+
Separation of the two complexes 8th+ and Ru(terpy)22+ was
performed by chromatography on silica gel eluted with an
acetone/water/aqueous saturated KNO3 mixture (10:1:0.1).
The electron-donating properties of the mesityl group in 2
as well as its hindering nature are suspected to be responsible
for these limited yields. In addition, the selective obtention
+
of the isomer 8th can be the consequence of the coordina-
tion, in a first process, of the nitrogen atom of the phenan-
throline which is the less hindered. ROESY analysis on
complex 8th+ showed that coordination of phenanthroline 2
to the ruthenium in complex Ru(1)Cl3 was stereoselective.
The only recovered complex was the isomer in which the
monodentate chloride ligand is on the same side as the anisyl
group of 2.
Chemical and Photochemical Reactivity of Complexes
of the Type Ru(1)(2)(L)n+. The chemical reactivity of Ru-
(1)(2)(L)n+ complexes is in line with previously published
work on related complexes (Scheme 4).17,18,30
+
Complex 8th reacted slowly in a refluxing acetonitrile-
2+
water mixture to afford complex 9th in which the mono-
(24) Miyaura, N.; Suzuki, A. Chem. ReV. 1995, 95, 2457-2483.
(25) Tzalis, D.; Tor, Y.; Failla, S.; Siegel, J. S. Tetrahedron Lett. 1995,
36, (20), 3489-3490.
dentate CH3CN ligand was still on the side of the anisyl
2+
group. Heating of 9th in pyridine at reflux leads quantita-
2+
tively to complex 10th in which pyridine is in the same
(26) Boldron, C.; Pitie´, M.; Meunier, B. Synlett 2001, 10, 1629-1631.
(27) Dietrich-Buchecker, C.; Sauvage, J.-P. Tetrahedron Lett. 1982, 23,
5291-5294.
position as acetonitrile in 9th2+. In both thermal reactions,
the absence of light was critical to ensure retention of the
geometrical coordination of the complexes. Suitable single
(28) Lu¨ning, U.; Mu¨ller, M. Chem. Ber. 1990, 123, 643-645.
(29) Calvert, J. M.; Schmehl, R. H.; Sullivan, B. P.; Facci, J. S.; Meyer,
T. J.; Murray, R. W. Inorg. Chem. 1983, 22, 2151-2162.
(30) Hecker, C. R.; Fanwick, P. E.; McMillin, D. R. Inorg. Chem. 1991,
30, 659-666.
2+
crystals of 10th were obtained by slow diffusion of an
acetone solution of the complex into diisopropyl ether. The
10522 Inorganic Chemistry, Vol. 46, No. 25, 2007

Acyclic Ruthenium(II) Complexes
2+
Figure 1. View of the crystal structure of the ruthenium complex 10th
.
Selected distances (Å) and angles (deg): Ru-N1 2.059(6), Ru-N2 1.965-
(6), Ru-N3 2.075(6), Ru-N4 2.076(6), Ru-N5 2.125(6), Ru-N6 2.097-
(6), N1-Ru-N2 79.9(2), N1-Ru-N3 158.9(2), N1-Ru-N4 95.2(2), N1-
Ru-N5 86.3(2), N2-Ru-N3 79.1(2), N2-Ru-N4 174.5(2), N3-Ru-
N4 105.8(2), N4-Ru-N6 92.5(2). H atoms and anions are omitted for
clarity. Ellipsoids are scaled to enclose 50% of the electronic density.
Figure 2. Proton NMR spectra of 10th2+ and 10photo2+ (aromatic region).
(blue) Peaks of the phenanthroline. (red) Peaks of the terpyridine. (green)
Peaks of the pyridine (noted PY). Scale is 9.5-6.3 ppm in acetone-d6.
2+
2+ a
molecular crystallographic structure with partial numbering
scheme is depicted Figure 1.
Scheme 5. Chemical Structures of Complexes 10th and 10photo
The bond lengths and N-Ru-N bond angles indicate that
the geometry about the ruthenium atom is distorted from
octahedral. In particular, a significant variation from the
theoretical value is observed for the Ru-N5 bond length
(2.12(6) Å) as a consequence of the steric constraint imposed
by the mesityl substituent located in the R position of the
nitrogen of the phenanthroline. The geometry in the solid
state is also consistent with the ROESY interactions observed
in solution. The mesityl group is located below the terpy-
ridine moiety with π stacking between the central pyridine
of the terpyridine and the mesityl aromatic cycle (average
distance between the two cycles is 3.4 Å). On the other side
of the ruthenium atom the pyridine ligand is close to the
anisyl group belonging to the phenanthroline. The torsion
angle O1-C20-C30-O2 is 45.71° and the two methoxy
groups pointed toward the same side of the molecule, so that
inclusion of this complex in a molecular ring could be
envisaged (see below). The O1-O2 distance is 17.89 Å in
this isomer.
2+
Visible light irradiation of 10th (λ g 340 nm) in neat
pyridine leads to another species as demonstrated by UV-
vis measurements (see Supporting Information) and 1H NMR
spectra (Figure 2) performed before and after irradiation.
As indicated by these spectra the photochemical reaction
was selective and quantitative. The ES-MS spectrum also
showed that the composition of the new complex is not
changed. Complete assignment of the 1H NMR spectrum by
a Red arrows indicate selected ROESY interactions.
proton Pm of the mesityl group and the protons ortho and
meta of the pyridine.
2+
Irradiation of 9th in acetonitrile leads to a similar
2+
photochemical isomerization since 9th is quantitatively
2+
2+
COSY and ROESY experiments clearly proves that 10photo
converted to isomer 9photo in which the phenanthroline
2+
is an isomeric form of 10th in which the mesityl group is
moiety rotated at a 90° angle and the acetonitrile ligand is
close to the pyridine and far from the terpyridine (Scheme
5). A correlation peak was also detected in 10th between
on same the side as the mesityl group. This isomerization
reaction was also directly carried out from complex 8th in
2+
+
the P9 proton of the phenanthroline and the meta proton of
acetonitrile/water and afforded in one quantitative step
9photo2+. In a similar manner, 9th irradiated in pyridine
2+
2+
the pyridine. Such a correlation peak is missing in 10photo
,
2+
while two correlation peaks were observed between the
directly afforded 10photo with 100% yield. Scheme 6
Inorganic Chemistry, Vol. 46, No. 25, 2007 10523

Bonnet et al.
Scheme 6. Photochemical Ligand Substitutions of Ru(1)(2)(L)n+
Complexes
structure of the starting isomer. For higher temperature, as
in refluxing DMSO, it appears that the thermodynamic
product can be obtained as the single product starting from
the photochemical isomer.
For the photochemical reactions, a dissociative mechanism
for this type of polypyridyl ruthenium(II) complexes has been
well established in previous works.30,32 Substitution of the
monodentate ligand was supposed to be an elementary step
occurring on the pentacoordinated species Ru(1)(2)2+ gener-
ated by ligand L abstraction from the starting complex.
Previous experimental data19 and theoretical TD-DFT
calculations33 were consistent with such transient pentaco-
ordinated species. Because of the dissymmetric substitution
pattern of phenanthroline 2, the two possible square-
pyramidal five-coordinate intermediates do not have the same
energy. As a consequence, steric hindrance due to the
bulkiness of the mesityl group might be large enough to
induce destabilization of a given five-coordinate intermediate
as compared to the other. Considering that the bimolecular
reaction between the pentacoordinated species and the
entering ligand is a slow step at room temperature compared
to the shift of the equilibrium between the five-coordinate
transient species, the whole process would result in a 100%
yield for the photochemical isomer at room temperature. The
drastic effect of the mesityl group on the yield of the
photochemical reaction is also in accordance with the results
obtained with analogous ruthenium complexes in which the
3-anisyl-9-mesityl-1,10-phenanthroline has been replaced by
the asymmetric 4-methyl-7-anisyl-1,10-phenanthroline. Vis-
ible light irradiation of any of the two possible thermal
isomers leads to a statistical mixture (50:50) of two
photochemical isomers. This photochemical behavior reflects
the lack of a bulky group at the R position of a nitrogen
atom of the phenanthroline. The details of these experiments
are given in the Supporting Information.
Synthesis of Macrocycles Including the Ru(terpy)-
(phen)(py)2+ Moiety. In the case of the Ru(phen)2 core,
Mobian et al. were able to synthesize a [2]-catenane by
threading a 6,6′-dimethylbipyridine chelate bearing olefin-
terminated chains inside a macrocycle containing a Ru(bis-
phen)Cl2 unit followed by ring-closing metathesis.16,34 Pre-
liminary results showed that in the case of the Ru(terpy)(phen)
core, coordination of terdentate, bidentate, or monodentate
ligands bearing terminal olefins on a ruthenium center led
to substantial polymerization and/or double-bond migration.
Such processes prevented the isolation of any Ru(terpy)-
(phen)(L)2+ complex surrounded by terminal olefins when
starting from inorganic ruthenium salts and olefin-bearing
free ligands. Another strategy toward macrocycles consisted
of introducing the terminal olefins by performing organic
chemistry on the periphery of ligands that were previously
coordinated around ruthenium in a stable, saturated Ru-
(terpy)(phen)(py)2+ complex. Reduction of all double bonds
summarizes the photochemical ligand substitution pattern of
Ru(1)(2)(L)n+ complexes.
The two isomers (thermal and photochemical) of one
particular complex have very similar UV-vis absorption
spectra with a bathochromically shifted shoulder for the
photochemical isomer that induced a slight color change after
2+
2+
isomerization (10th was bright orange, whereas 10photo
was brownish). This shoulder was suspected to be caused
by an intraligand π-π* charge-transfer transition from the
donating mesityl group to the electron-deficient central ring
of the terpyridine unit.
Chemical Reactivity of the Photochemically Produced
Isomers. If the photochemical isomers of Ru(1)(2)(L)n+
complex (L ) CH3CN or pyridine) are subjected to thermal
ligand substitution reactions, ligand replacement of L gener-
ally leads to retention of the coordination geometry charac-
teristic of the photochemical isomer. This was the case with
pyridine, 3,5-dimethylpyridine, and benzonitrile, acting both
as ligand and solvent. In the case of the chloride ion as
+
entering ligand, in refluxing dichloroethane, a mixture of 8th
and 8photo+ was obtained in a ratio of 13:87. In DMSO back-
isomerization to the thermal isomer was quantitatiVe; in this
process, pyridine was quantitatively removed, yielding the
2+
thermal S-bonded isomer Ru(1)(2)(CH3SOCH3)2+ (11th
)
and the thermal O-bonded isomer in a ratio of 90:10. These
two products decompose on silica gel, but crude samples
1
can be precipitated and isolated. Their study by H NMR,
electrospray mass spectrometry, and UV-vis absorption
spectroscopy confirm the hypothesis of a mixture of S-
bonded and O-bonded DMSO thermal isomers. The wave-
length maxima at 437 and 490 nm are in agreement with
the literature data,31 and the peak in the mass spectrum at
m/z ) 499.642 (calcd 499.638) unambiguously proves the
presence of a coordinated DMSO ligand.
Possible Mechanisms for the Thermal and Photochemi-
cal Reactions. From the experimental data two different
mechanisms can be invoked independently in the thermal
and photochemical reactions.
For the thermal reactions, at moderate temperature
(<140 °C), an associative mechanism is in agreement with
retention of the coordination geometry regardless of the
(32) Suen, H.-F.; Wilson, S. W.; Pomerantz, M.; Walsh, J. L. Inorg. Chem.
1989, 28, 786-666791.
(33) Bossert, J. Ph.D. Thesis, Louis Pasteur University, Strasbourg, France,
2004.
(31) Rack, J. J.; Winkler, J. R.; Gray, H. B. J. Am. Chem. Soc. 2001, 123,
2432-2433.
(34) Arico, F.; Mobian, P.; Kern, J.-M.; Sauvage, J.-P. Org. Lett. 2003, 5,
1887-1890.
10524 Inorganic Chemistry, Vol. 46, No. 25, 2007

Acyclic Ruthenium(II) Complexes
Scheme 7. Synthesis of the Precursor Complexes for the Grubbs
Cyclization
Scheme 8. Synthesis of the Thermally and Photochemically Reduced
Ruthena-macrocycles
before any ligand-exchange experiments would be necessary.
Complexes 10th2+ and 10photo2+ were used as starting material
for inclusion of the Ru(terpy)(phen) core in macrocyclic
species. Pyridine, being strongly coordinated to the Ru-
(terpy)(phen) core, acted as a protecting group for the
monodentate coordination site. In these conditions, four
organic reactions performed “on the complex” enabled the
synthesis of macrocyclic species. (i) As a first step, boron
tribromide deprotection of the methoxy groups in 10th2+ and
finished within 2 days and led to a single major product
analyzed by ES-MS as the monomeric macrocycle in 70-
80% yield. (iv) In order to avoid unexpected side reactions
on the olefin function during photoinduced or thermal ligand
substitution reactions on the Ru(terpy)(phen)(L)n+ macro-
cyclic complexes, 152+ and 162+ were reduced by hydroge-
nation over Pd/C. This last catalytic step quantitatively
afforded the four corresponding macrocycles with a (CH2)18
2+
10photo2+ quantitatively afforded the phenol complexes 12th
2+
alkane chain (17th and 17photo2+) or a (CH2CH2O)3-
and 12photo2+, respectively. (ii) Subsequent alkylation using
(CH2)4-(CH2CH2O)3 polyethylene glycol chain (18th2+ and
18photo2+). The last two steps are described in Scheme 8.
ROESY studies clearly showed that in 17th2+ and 18th2+ the
pyridine monodentate ligand was located inside the macro-
cyclic cavity, whereas in 17photo2+ and 18photo2+ it was outside
the macrocycle.
alkane or poly(ethylene glycol) chains in Williamson condi-
2+
tions afforded the four precursor complexes 13th2+, 14th
,
13photo2+, and 14photo2+ bearing terminal olefins (Scheme 7).
(iii) Grubbs’ first-generation olefin metathesis reactions were
used as the cyclization step. As is generally the case for this
reaction,35 the geometry of the precursor was a critical
parameter for preparation of monomeric macrocycles. A
Interconversion between Thermal and Photochemical
2+
Macrocycles.Themacrocyclicrutheniumcomplexes17th2+,18th
,
2+
priori, the geometry of the photoisomers (13photo or
17photo2+, and 18photo have been submitted to the same
reaction conditions as their acyclic counterparts 10th and
2+
14photo2+) is much more favorable to formation of a ring than
that of its thermal analogue. As expected, the thermal and
photochemical isomers reacted very differently: in the case
of the thermal isomers, 5-7 days were needed to complete
the reaction. The monomer yields were low, typically around
25%, and an appreciable amount of the dimer was isolated
and clearly identified by electrospray mass spectrometry. In
the case of the photochemical isomers, the reaction was
2+
10photo2+. These experiments unambiguously led to the same
results as in the case of the acyclic complexes and without
noticeable difference between the alkane or poly(ethylene
glycol) (PEG) chains. Irradiation of the thermal isomers in
pyridine led quantitatively to ligand exchange and isomer-
ization. Thermal back-isomerization only took place in
dimethyl sulfoxide at 140 °C for 2 h, all other solvents
(acetonitrile, pyridine, 3,5-lutidine, or benzonitrile) leading
to ligand substitution without back-isomerization. DMSO,
(35) Belfrekh, N.; Dietrich-Buchecker, C.; Sauvage, J.-P. Inorg. Chem.
2000, 39, 5169-5172.
Inorganic Chemistry, Vol. 46, No. 25, 2007 10525

Bonnet et al.
Scheme 9. Square Reaction Scheme Leading To Interconversion
between the Photochemical and Thermal Isomers
being only weakly coordinated to the ruthenium center in
the thermal isomers of the macrocyclic complexes, thermal
ligand exchange in refluxing pyridine, acetonitrile, or dichlo-
romethane solution of tetraethylammonium chloride, afforded
the corresponding thermal macrocycle with a pyridine,
acetonitrile, or chloride ligand inside the macrocyclic cavity.
The interconversion scheme in the case of the (CH2)18 alkane
chain is depicted in Scheme 9 (photochemical macrocycles
with L ) 3,5-dimethylpyridine and benzonitrile are denoted
2+
Figure 3. 1H 500 MHz NMR spectra of the alkane chains in 17th and
17photo2+ (a and b, respectively) and the polyethylene glycol chains in 18th
2+
2+
and 18photo (c and d, respectively).
conformation of the chain. NMR spectroscopy could, in
principle, measure the difference in chain mobility between
thermal and photochemical macrocyclic complexes. Figure
3a and b depicts the change of the alkane region (4.5-0.5
ppm in CD2Cl2) of the NMR spectrum of 17th2+ and 17photo
,
2+
2+
19photo and 20photo2+, respectively; thermal macrocycles
and Figure 3c and d gives the corresponding analysis in the
ether region for 18th2+ and 18photo2+ (4.5-3.25 ppm in CD2-
Cl2, see Scheme 8 for proton assignments). Obvious broad-
ening of the peaks was observed in 17th2+ and 17photo2+ going
from RT,RP to γT,γP, which demonstrated that the conforma-
tions close to the aromatic anchors were well fixed, whereas
in the middle of the chain the number of available conforma-
tions was very high. As can be seen in Figure 3, the
with L ) acetonitrile, chloride, and DMSO are denoted
21th2+, 22th2+, and 23th2+, respectively).
Analysis of the Conformations of the Flexible Chains.
2+
In the crystal structure of 10th the O1-O2 distance was
17.89 Å. Chem3D molecular modeling calculations pre-
dicted that this distance could be shortened by rotation of
the C8-C16 single bond. The minimum value of 15.9 Å
was obtained in the conformer where the directions of the
two anisyl groups were included in the plane of the
phenanthroline. Unfortunately 10photo2+ could not be crystal-
lized, but the same molecular modeling analysis performed
on this isomer gave as the shortest value 6.3 Å. Keeping in
mind that molecular modeling gives only an evaluation of
the distances, this analysis would imply that the O1-O2
distance in the thermal isomer was two to three times longer
than that in the photochemical isomer.
2+
dissymmetry of the ring in the thermal isomers 17th and
18th2+ was weakly pronounced, and most of the CH2 signals
of the side of the phen and of the side of the terpy had similar
chemical shifts. This resulted in a lack of resolution that
prevented any quantitative conformational analysis based on
coupling constants. By contrast, in the photochemical isomers
17photo and 18photo2+, both sides (phen and terpy) were
clearly distinguished, except in the 1.0-1.5 ppm region for
17photo where the resolution was still too low. In these
2+
2+
In complexes 172+ and 182+ where a flexible chain has
been attached to these oxygen atoms, the huge variation of
the O1-O2 distance induced by the 90° rotation of the
phenanthroline moiety may lead to a dramatic change in the
isomers the dissymmetric nature of the macrocycles obvi-
3
ously appeared. However, the J coupling constants for the
2+
2+
RT,RP, âT,âP, and γT,γP peaks in 17th and 17photo were
not conclusive, and the inherent complexity of the signals
10526 Inorganic Chemistry, Vol. 46, No. 25, 2007

Acyclic Ruthenium(II) Complexes
2+
in 18photo prevented us from running quantitative confor-
metal surfaces like corn ears in a corn field,44 or by wrapping
the chains in a helical fashion around polyalkyne wires
through metal-templated synthesis.45 However, to our knowl-
edge, switching processes controlled by an external signal
and inducing a major conformational change of a flexible
chain has not been achieved yet.
mational analysis. Despite this lack of quantitative data, the
spectra in Figure 3 qualitatively demonstrate the dramatic
geometrical changeover of the macrocycles when changing
from the thermal isomers to the photochemical ones.
Conclusion
In this work, a stiff Ru(terpy)(phen) subunit was inscribed
in a molecular ring by organic chemistry performed on the
two isomers of complex Ru(1)(2)(py)2+. In order to connect
the terpy unit and the phen motif, an alkane and a poly-
(ethylene glycol) chain have been used. In both cases, the
photochemically induced isomerization of the ruthenium
complex and the reverse thermal reaction in DMSO were
observed with no change compared to the acyclic species.
This controlled rotation motion of the phenanthroline moiety
around ruthenium induced a major change in the conforma-
tions of the flexible chains. Such high-yield conformational
reorganization was performed due to the 2- to 3-fold variation
of the distance between the two oxygen atoms hooking the
extremities of the molecular string to the complex. In parallel,
the monodentate pyridine ligand located outside the ring in
the photochemical isomer moved to an intracavity position
in the thermal isomer. The thermal macrocycles including
the Ru(terpy)(phen)(CH3CN)2+ moiety with the monodentate
coordination site inside the ring will be used in future metal-
templated synthesis of interlocking molecules like [2]-cat-
enanes and rotaxanes.
The two chelates 1 and 2 in which 1 is a terpyridine
derivative and 2 is a 2,8 dissymmetrically substituted 1,10-
phenanthroline were synthesized and coordinated to ruthe-
nium(II). The corresponding series of complexes with the
formula Ru(1)(2)(L)n+ displayed a classical reactivity under
thermal ligand-exchange conditions with L ) Cl-, CH3CN,
or C5H5N. However, a novel isomerization phenomenon
consisting of a quantitative 90° rotation of the phenanthroline
moiety took place at room temperature under visible light
irradiation. The reverse motion was shown to take place only
by heating the complex in dimethyl sulfoxide at 140 °C for
2 h. Although photoisomerization of double bonds is a classic
in photochemistry, photoinduced isomerization inside the
coordination sphere of a ruthenium atom has not been
reported much.36 In Ru(bpy)2(OH2)22+ indeed, trans-cis and
cis-trans isomerization occur via the pentacoordinated
species derived from the starting complex by photoexpulsion
of H2O. This system was characterized by a trans/cis ratio
of 3:2 at the photostationary state. In the system described
in the present paper, photoinduced conversion to the pho-
tochemical isomer was quantitative. Although quantitative
calculation would be needed for a more complete under-
standing of this system, an analysis based on the interactions
between the mesityl group of phenanthroline 2 and (i)
terpyridine 1 bearing a phenyl substituent in 4′ position or
(ii) the monodentate ligand L′ entering into the coordination
sphere of the ruthenium during the substitution reaction is
proposed.
Experimental Section
Single-crystal X-ray diffraction experiments were carried out
using Kappa CCD and graphite-monochromated Mo KR radiation
(λ ) 0.71073 Å). For all computations the MolEN package was
1
used,46 and structures were drawn using CRYSTALMAKER. H
NMR spectra were acquired on either a Bruker AVANCE 300
(300 MHz), Bruker AVANCE 400 (400 MHz), or Bruker AVANCE
500 (500 MHz) spectrometer using the deuterated solvent as the
lock and residual solvent as the internal reference. Mass spectra
were obtained using a VG ZAB-HF(FAB) spectrometer, a VG-
BIOQ triple quadrupole, positive mode, or a Bruker MicrOTOF
spectrometer (ES-MS). UV-vis spectra were recorded with a
Kontron Instruments UVIKON 860 spectrometer at room temper-
ature.
(2(2-Bromoethoxy)ethoxy)ethyl allyl ether was prepared accord-
ing to the literature procedure34 using lithium bromide instead of
sodium iodide. Pyridine was distilled and kept over KOH under
argon. Dimethyl sulfoxide was distilled and kept under argon.
Ammonium acetate and tetraethylammonium chloride were com-
mercial product dried overnight under vacuum. 1,10-Phenanthroline
hydrochloride, paramethoxyphenyl boronic acid, palladium tetrakis-
(triphenylphosphine), 3,5-lutidine, benzonitrile, acetonitrile, 3-bro-
mobenzaldehyde, 2-acetylpyridine, 10-bromo-dec-1-ene, 2-bro-
momesitylene, and Grubbs’ first-generation catalyst were commercial
products. RuCl3‚xH2O was kindly provided by Johnson Matthey
Inc. Dichloromethane was distilled under CaH2. Tetrahydrofuran,
Unlike flexible nitrogen-, sulfur-, or phosphorus-bearing
ligands,37,38 alkane chains cannot be preorganized by metal-
heteroatoms interactions, and oxygen-bearing polyethylene
glycol chains (PEG) coordinate to metals only in the presence
of cooperative effects like in crown ether or cavitands.39 As
a result, controlling the conformations of long alkanes or
acyclic PEG chains is difficult and can be only realized by
using stiff elements that force the chain to adopt a given set
of conformations. Some interesting experimental results have
been obtained by enclosure of alkanes or PEG chains inside
self-assembled molecular cages,40-43 by packing them on
(36) Durham, B.; Wilson, S. W.; Hodgson, D. J.; Meyer, T. J. J. Am. Chem.
Soc. 1980, 102, 600-607.
(37) Piguet, C.; Borkovec, M.; Hamacek, J.; Zeckert, K. Coord. Chem.
ReV. 2005, 249, 705-726.
(38) Swiegers, G. F.; Malefetse, T. J. Chem. ReV. 2000, 100, 3483-3537.
(39) Lehn, J.-M. La Chimie Supramole´culaire-concepts et perspectiVes;
De Boeck Universite´: Brussels, Belgium, 1997; p 273.
(40) Trembleau, L.; Rebek, J., Jr. Science 2003, 301, 1219-1220.
(41) Scarso, A.; Trembleau, L.; Rebek, J., Jr. J. Am. Chem. Soc. 2004,
126, 13512-13518.
(42) Scarso, A.; Trembleau, L.; Rebek, J., Jr. Angew. Chem., Int. Ed. 2003,
42, 5499-5502.
(43) Love, J. C.; Wolfe, D. B.; Haasch, R.; Chabinyc, M. L.; Paul, K. E.;
Whitesides, G. M.; Nuzzo, R. G. J. Am. Chem. Soc. 2003, 125, 2597-
2609.
(44) Love, J. C.; Estroff, L. A.; Kriebel, J. K.; Nuzzo, R. G.; Whitesides,
G. M. Chem. ReV. 2005, 105, 1103-1169.
(45) Stahl, J.; Bohling, J. C.; Bauer, E. B.; Peters, T. B.; Mohr, W.; Martin-
Alvarez, J. M.; Hampel, F.; Gladysz, J. A. Angew. Chem., Int. Ed.
2002, 41, 1871-1876.
(46) Fair, C. K. MolEN, An interactiVe intelligent system for crystal
structure analysis; Nonius: Delft, The Netherlands, 1990.
Inorganic Chemistry, Vol. 46, No. 25, 2007 10527

Bonnet et al.
diethyl ether, and toluene were distilled and dried over sodium.
Acetone was distilled and dried over sodium sulfate. KPF6 was
used as a 40 g/L aqueous solution. KNO3 was used as a saturated
aqueous solution. In every synthesis of ruthenium complexes
chromatography fractions were worked up as follows: addition of
an excess amount of KPF6, evaporation of the organic solvent
(acetone or acetonitrile) until precipitation, filtration, washing with
water, recovery from the frit with acetone, and drying under
vacuum.
Characterization of 2′. 1H 300 MHz NMR (δ in ppm in
CDCl3): 9.19 (dd, 1H, P9, J ) 4.3,1.7 Hz); 8.23 (dd, 1H, P7, J )
8.1,1.9 Hz); 8.23 (s, 1H, P4); 7.85 (d, 1H, P5, J ) 8.8 Hz); 7.79 (d,
1H, P6, J ) 8.8 Hz); 7.58 (dd, 1H, P8, J ) 8.1,4.3 Hz); 7.15 (d,
2H, Pa, J ) 9.1 Hz); 6.78 (s, 2H, Pm); 6.77 (d, 2H, Pb, J ) 9.1 Hz);
3.77 (s, 3H, POMe); 2.26 (s, 3H, Mep); 1.93 (s, 6H, Me°).
3. In a 500 mL two-necked round-bottom flask 29.6 g (160
mmol) of 3-bromobenzaldehyde was dissolved in 250 mL of
methanol. To the well-stirred solution were successively added 18
mL (160 mmol) of 2-acetylpyridine and a solution of 6.4 g of
sodium hydroxide in 50 mL of water. The solution was stirred at
room temperature for 15 min. The white precipitate was filtered,
washed with water, and dissolved in dichloromethane. The organic
phase was still washed once with water and evaporated to dryness
to yield 28.2 g of chalcone 3 (61%). 1H 500 MHz NMR (δ in ppm
in CDCl3): 8.75 (dq, 1H, T6′′, J ) 4.8,0.9 Hz); 8.29 (d, 1H, T4′, J
) 16.1 Hz); 8.19 (dt, 1H, T3′′, J ) 7.7,1.2 Hz); 7.88 (td, 1H, T4′′,
J ) 7.7,1.8 Hz); 7.88 (s, 1H, TA); 7.84 (d, 1H, T3′, J ) 16.1 Hz);
7.62 (d, 1H, TC, J ) 7.7 Hz); 7.51 (m, 2H, TE + T5′′); 7.28 (t, 1H,
TD, J ) 7.9 Hz). Anal. Calcd for C14H10BrNO: C, 58.36; H, 3.50;
N, 4.86. Found: C, 58.48; H, 3.72; N, 4.77.
1. A 1.16 g (3.0 mmol) amount of 4′-(3-bromophenyl)terpyridine
was dissolved in 100 mL of toluene in a three-necked 250 mL
round-bottom flask. The flask was put under argon; 173 mg (150
µmol, 5 mol %) of palladium tetrakis(triphenylphosphine) was
added under argon. A 20 mL amount of 2 M degassed sodium
carbonate aqueous solution was cannulated, followed by 502 mg
(3.30 mmol) of p-anisylphenyl boronic acid dissolved in 50 mL of
toluene and 8 mL of ethanol. The reaction mixture was degassed
and refluxed under argon overnight. The solvents were evaporated,
and water was added and extracted with dichloromethane. The
organic phase was washed once with water and evaporated. The
product was purified on neutral alumina (200 mL) using a 3:7
to 35:15 diethyl ether/pentane mixture as the eluent. Yield: 879
mg of terpyridine 1 (71%). 1H 500 MHz NMR (δ in ppm in
CDCl3): 8.79 (s, 2H, T3′5′); 8.73 (m, 2H, T66′′); 8.68 (dt, 2H,
T33′′, J ) 7.9,1.1 Hz); 8.05 (t, 1H, TA, J ) 1.8 Hz); 7.88 (td, 2H,
T44′′, J ) 7.7, 1.8 Hz); 7.82 (m, 1H, TE); 7.64-7.61 (m, 3H, TC
+ Ta); 7.56 (t, 1H, TD, J ) 7.7 Hz); 7.35 (m, 2H, T55′′); 7.02
(d, 2H, Tb, J ) 8.8 Hz); 3.87 (s, 3H, OMe). HR FAB MS m/z
(calcd): 416.1769 (416.1762, [M + H]+). Anal. Calcd for
C28H21N3O: C, 80.94; H, 5.09; N, 10.11. Found: C, 80.69; H, 5.17;
N, 10.03.
6. In a 500 mL two-necked round-bottom flask was added 3.00
g (11.6 mmol) of 3-bromophenanthroline, 150 mL of toluene, and
a stirring bar. The flask was put under argon, 669 mg (580 µmol,
5 mol %) of palladium tetrakis(triphenylphosphine) was added under
argon, 60 mL (120 mmol) of a degassed 2 M aqueous sodium
carbonate solution, and a degassed solution containing 2.12 g (13.9
mmol) of paramethoxyphenyl boronic acid in 100 mL of toluene
and 15 mL of ethanol were successively cannulated into the reaction
flask. The solution was degassed and refluxed under argon
overnight. The solvents were evaporated, water was added and
extracted with dichloromethane, and the organic phase was washed
with water and evaporated to dryness. The crude product (5.05 g)
was purified by chromatography on silica gel using dichlo-
romethane/methanol mixtures as eluents to yield 3.01 g of phenan-
2. A 434 mg (2.18 mmol) amount of mesityl bromide was put
under argon in a 100 mL round-bottom flask. A 50 mL amount of
dry diethyl ether was cannulated, 1.57 mL of n-butyllithium (1.37
M, 2.15 mmol) was added, and the mixture was stirred under argon
for 5 h. In a three-necked 250 mL round-bottom flask, 513 mg of
3-anisylphenanthroline was weighed and dissolved in 150 mL of
dry diethyl ether or toluene under argon. The ether solution of
aryllithium was dropwise cannulated at room temperature into the
reaction flask, leading to a fast color change from colorless to deep
violet. The solution was stirred under argon at room temperature
for 20 h and quenched with 25 mL of water. The solvents were
evaporated, and water was added and extracted with dichlo-
romethane. To the combined yellow dichloromethane extracts was
added 10 equiv (1.6 g) of manganese dioxide. The solution was
stirred at room temperature for 5 min, and this procedure was
repeated twice again. The manganese oxide was filtered on celite,
and the clear solution was evaporated to dryness, yielding 728 mg
of re-aromatized crude product. The two phenanthroline regioiso-
mers were separated on acidic alumina (200 mL) using a 20:2:2
pentane/dichloromethane/ethylacetate mixture as the eluent.
Yield: 188 mg (26%) of 2 (isomer 2,8) and 143 mg (19%) of 2′
(isomer 2,3).
1
throline 6 (91%). H 300 MHz NMR (δ in ppm in CDCl3): 9.33
(d, 1H, P2, J ) 2.4 Hz); 9.10 (dd, 1H, P9, J ) 4.4,1.8 Hz); 8.16 (d,
1H, P4, J ) 2.3 Hz); 8.08 (dd, 1H, P7, J ) 8.1,1.8 Hz); 7.63 (d,
2H, Pa, J ) 3.3 Hz); 7.61-7.58 (m, 2H, P5 + P6); 7.49 (dd, 1H,
P8); 6.96 (d, 2H, Pb, J ) 8.8 Hz); 3.77 (s, 3H, POMe). Anal. Calcd
for C19H14N2O: C, 79.70; H, 4.93; N, 9.78. Found: C, 79.54; H,
4.88; N, 9.66.
7. A 4.10 g (9.87 mmol) amount of 4′-(3-anisylphenyl)-2,2′;6′,2′′-
terpyridine and 2.59 g (9.9 mmol) triaquaruthenium trichloride was
mixed in 500 mL of ethanol and refluxed under air for 1 h. The
mixture was cooled to room temperature and filtered. The solid
was washed twice with ethanol and dried to yield 5.84 g of a brown
solid (95%). FAB MS m/z (calcd): 621.9 (622.0, [M]+); 586.9
(587.0, [M - Cl]+); 552.0 (552.0, [M - 2Cl]+); 517.0 (517.1, [M
- 3Cl + H]+).
8th+. A 185 mg (297 µmol) amount of 7, 40 mL of ethanol, and
53 mg (1.24 mmol) of lithium chloride were mixed in a two-necked
250 mL round-bottom flask. A 100 mg (248 µmol) amount of
8-anisyl-2-mesitylphenanthroline was dissolved in 40 mL of hot
ethanol and added to the reaction mixture. A 20 mL amount of
water and 2 mL of triethylamine were added; the reaction flask
was put under argon and refluxed for 4 h. The violet complex
precipitated after addition of 50 mL of KPF6 and 30 mL of water
at room temperature; the precipitate was filtered, washed with water,
recovered with acetone, and dried. A minimum amount of acetone
was added to dissolve the crude material, toluene was added until
complete precipitation of the complex, and the remaining free
phenanthroline, soluble in toluene, was removed by filtration. The
Characterization of 2. 1H 500 MHz NMR (δ in ppm in CDCl3):
9.42 (d, 1H, P9, J ) 2.5 Hz); 8.34 (d, 1H, P7, J ) 2.5 Hz); 8.28 (d,
1H, P4, J ) 8.2 Hz); 7.85 (s, 2H, T3′5′); 7.71 (d, 2H, Pa, J ) 8.8
Hz); 7.55 (d, 1H, P3, J ) 8.2 Hz); 7.07 (d, 2H, Pb, J ) 8.8 Hz);
6.95 (s, 2H, Pm); 3.89 (s, 3H, POMe); 2.35 (s, 3H, Mep); 2.09 (s,
6H, Me°). HR FAB MS m/z (calc): 405.1971 (405.1967, [M +
H]+). Anal. Calcd for C28H24N2O: C, 83.14; H, 5.98; N, 6.93,
Found: C, 82.91; H, 6.10; N, 6.87.
10528 Inorganic Chemistry, Vol. 46, No. 25, 2007

Acyclic Ruthenium(II) Complexes
violet solid was recovered with acetone, dried, and purified by
chromatography on silica gel using a 500:5:0.5 mixture of acetone,
water, and KNO3. Yield: 147 mg of analytically pure [8th][PF6].
1H 500 MHz NMR (δ in ppm in CDCl3): 10.88 (d, 1H, P9); 8.83
(d, 1H, P7); 8.32 (d, 1H, P6, J ) 8.9 Hz); 8.23 (d, 1H, P4); 8.22 (d,
2H, T33′′); 8.11 (d, 1H, P5, J ) 8.9 Hz); 8.07 (s, 2H, T3′5′); 7.97 (d,
2H, Pa, J ) 8.0 Hz); 7.90 (s, 1H, TA); 7.72 (m, 1H, TE); 7.68 (d,
2H, Ta); 7.68 (td, 2H, T44′′); 7.67 (m, 1H, TC); 7.57 (m, 1H, TD);
7.44 (d, 2H, T66′′, J ) 5.5 Hz); 7.10 (d, 2H, Pb, J ) 8.0 Hz); 7.07
(m, 2H, T55′′); 7.02 (d, 2H, Tb, J ) 8.0 Hz); 6.94 (d, 1H, P3, J )
8.2 Hz); 6.37 (s, 2H, Pm); 3.87 (s, 3H, TMeO); 3.85 (s, 3H, PMeO);
1.86 (s, 3H, Mep); 0.74 (s, 6H, Meo). UV-vis (λmax (ꢀ in L mol-1
cm-1) in acetone): 515 nm (17 100). ES MS m/z (calcd): 956.2305
(956.2305, [M - PF6]+).
9th2+. A 131 mg (119 µmol) amount of [8th][PF6] was dissolved
in a mixture of 80 mL of acetonitrile and 20 mL of water. The
solution was degassed and refluxed under argon for 2 days.
Complete precipitation of the complex was obtained by adding
enough KPF6 at room temperature. The orange precipitate was
filtered, washed with water, recovered with acetone, dried, and
purified on silica gel using a 80:5:0.5 acetonitrile/water/KNO3
mixture as the eluent. Yield: 112 mg (75%) of [9th][PF6]2. 1H 300
MHz NMR (δ in ppm in CD3CN): 9.94 (d, 1H, P9); 9.11 (d, 1H,
P7); 8.54 (s, 2H, T3′5′); 8.52 (m, 2H, T33′′); 8.49 (d, 1H, P4); 8.44
(d, 1H, P6, J ) 8.9 Hz); 8.33 (s, 1H, TA); 8.27 (d, 1H, P5, J ) 8.9
Hz); 8.06 (m, 5H, Pa + T44′′ + TE); 7.86 (m, 3H, Ta + TC); 7.81
(m, 1H, TD); 7.61 (m, 2H, T66′′); 7.24 (m, 5H, P3 + Tb + T55′′);
7.16 (d, 2H, Pb, J ) 8.0 Hz); 6.53 (s, 2H, Pm); 3.91 (s, 3H, TMeO);
3.90 (s, 3H, PMeO); 2.08 (s, 3H, ANCH3); 1.98 (s, 3H, Mep); 0.86
(s, 6H, Me°). ES MS m/z (calcd): 481.136 (481.144, [M -
2PF6]2+); 460.62 (460.63, [M - CH3CN - 2PF6]2+).
2H, Pb, J ) 8.8 Hz); 6.63 (s, 2H, Pm); 3.90 (s, 3H, TMeO); 3.86 (s,
3H, PMeO); 2.03 (s, 3H, Mep); 0.98 (s, 6H, Me°). UV-vis (λmax (ꢀ
in L mol-1 cm-1) in acetone): 485 nm (17 900). ES MS m/z
(calcd): 500.157 (500.152, [M - 2PF6]2+); 1145.280 (1145.268,
[M - PF6]+).
10photo2+. Thermal Preparation. A 64 mg (51 µmol) amount of
[9photo][PF6]2 was dissolved in 5 mL of pyridine. The solution was
degassed and refluxed under argon for 2 h. Precipitation was
obtained by addition of KPF6 at room temperature; the solid was
filtered, washed with water, and recovered with acetone. Yield:
65 mg (100%) of [10photo][PF6]2.
Photochemical Preparation. A 64 mg (51 µmol) amount of
9[PF6]2 (either thermal or photochemical isomer) was dissolved in
3 mL of pyridine. The solution was degassed and white-light
irradiated for 1 h at room temperature with a 1000 W xenon arc
lamp filtered by a water filter. Precipitation was obtained by addition
of KPF6; the solid was filtered, washed with water, and recovered
with acetone. Yield: 66 mg (100%) of [10photo][PF6]2. 1H 500 MHz
NMR (δ in ppm in acetone-d6): 9.14 (s, 2H, T3′5′); 9.13 (d, 1H,
P4, J ) 7.8 Hz); 8.90 (d, 2H, T33′′, J ) 7.8 Hz); 8.78 (d, 1H, P7, J
) 2.0 Hz); 8.57 (d, 1H, P5, J ) 9.0 Hz); 8.38 (d, 1H, P6, J ) 8.4
Hz); 8.30 (m, 3H, TA + T66′′); 8.19 (td, 2H, T44′′, J ) 7.8,1.5 Hz);
8.07 (d, 1H, P3, J ) 8.4 Hz); 8.05 (m, 1H, TE); 8.04 (d, 2H, P9, J
) 2.0 Hz); 7.84 (d, 1H, TC, J ) 8.5 Hz); 7.74 (d, 2H, Ta, J ) 9.0
Hz); 7.70 (t, 1H, TD, J ) 7.8 Hz); 7.59 (t, 1H, PYp, J ) 7.8 Hz);
7.55 (m, 2H, T55′′); 7.31 (d, 2H, Pa, J ) 8.4 Hz); 7.27 (d, 2H, PYo,
J ) 5.4 Hz); 7.08 (d, 2H, Tb, J ) 8.4 Hz); 6.87 (d, 2H, Pb, J ) 8.4
Hz); 6.85 (t, 2H, PYm, J ) 7.2 Hz); 6.43 (s, 2H, Pm); 3.87 (s, 3H,
T
MeO); 3.73 (s, 3H, PMeO); 2.16 (s, 6H, Me°); 2.03 (s, 3H, Mep).
ES MS m/z (calcd): 500.146 (500.152, [M - 2PF6]2+); 1145.266
(1145.268, [M - PF6]+). UV-vis (λmax (ꢀ in L mol-1 cm-1) in
acetone): 482 nm (13 700).
9photo2+. A 50 mg (45 µmol) amount of [8th][PF6] was dissolved
in 4 mL of acetonitrile and 2 mL of water, put under argon, and
white-light irradiated for 1 h at room temperature with a 1000 W
xenon arc lamp filtered by a water filter. The resulting orange
solution was transferred in 20 mL of KPF6 upon which precipitation
occurred. The solid was filtered, washed with water, recovered with
acetone, and dried to yield 52 mg (100%) of the photochemical
8photo+. A sample containing 5.0 mg (3.8 µmol) of [10photo][PF6]2
and 5.1 mg (31 µmol) of tetraethylammonium chloride in C2D2Cl4
was prepared. The closed NMR tube was heated at 140 °C for 2 h
in the dark and directly analyzed in the NMR spectrometer. Yield:
87% of [8photo][PF6] and 13% of [8th][PF6]. 1H 500 MHz NMR (δ
in ppm in CDCl3): 8.70 (P4); 8.34 (T3′5′); 8.22 (T33′′); 8.22 (P5);
8.20 (P7); 8.09 (P6); 7.93 (P3); 7.93 (TA); 7.72 (TC); 7.70 (TE); 7.65
(T66′′); 7.65 (TD); 7.63 (P9); 7.60 (T44′′); 7.13 (Pa); 7.08 (T55′′); 6.96
(Ta); 6.95 (Ta); 6.87 (Pb); 6.84 (Pm); 3.87 (TOMe); 3.70 (POMe); 2.21
(Mep); 2.16 (Me°). UV-vis (λmax (ꢀ in L mol-1 cm-1) in acetone):
517 nm (11 000). ES MS m/z (calcd): 956.25 (956.23, [M - PF6]+).
11th2+. A sample containing 5.0 mg (3.8 µmol) of [10photo][PF6]2
in CD3SOCD3 was prepared. The closed NMR tube was heated at
140 °C for 2 h in the dark, yielding a mixture of O-bonded and
S-bonded thermal complexes. After waiting at room temperature
for 8 h in the dark, the mixture evolved and the major product
(S-bonded) remained almost alone. This complex was precipitated
with KPF6, washed with water, recovered with acetone, and dried,
but purification on silica gel was impossible as it led to decomposi-
tion. Yield of [11th][PF6]2 > 95%. When [11th][PF6]2 was dissolved
in acetonitrile, pyridine, or a dichloromethane solution of tetra-
ethylammonium chloride and refluxed for 2 h under argon and in
the dark it afforded complexes [9th][PF6]2, [10th][PF6]2, or [8th][PF6],
respectively. These complexes were purified on silica gel (acetone/
water/KNO3 80:5:0.5) with an overall yield (from the photochemical
isomer) of ≈85%.
1
isomer [9photo][PF6]2. H 300 MHz NMR (δ in ppm in CD3CN):
8.92 (d, 1H, P4, J ) 8.3 Hz); 8.83 (s, 2H, T3′5′); 8.58-8.55 (m,
3H, P7 + T33′′); 8.41 (d, 1H, P5, J ) 8.8 Hz); 8.32 (t, 1H, TA, J )
1.9 Hz); 8.21 (d, 1H, P6, J ) 8.8 Hz); 8.09-7.99 (m, 4H, TE + P3
+ T44′′); 7.93-7.82 (m, 4H, TC + P9 + Ta); 7.80 (t, 1H, TD, J )
7.9 Hz); 7.71-7.69 (m, 2H, T66′′); 7.31 (d, 2H, Pa, J ) 8.9 Hz);
7.23 (m, 2H, T55′′); 7.12 (d, 2H, Tb, J ) 8.8 Hz); 6.94 (s, 2H, Pm);
6.90 (d, 2H, Pb, J ) 8.9 Hz); 3.88 (s, 3H, TMeO); 3.74 (s, 3H, PMeO);
2.24 (s, 3H, Mep); 2.09 (s, 6H, Me°). ES MS m/z (calcd): 460.6316
(460.6311, [M - 2PF6 - CH3CN]2+); 1107.2534 (1107.2534, [M
- PF6]+). UV-vis: (λmax (ꢀ in L mol-1 cm-1) in acetone): 461
nm (12 500).
10th2+. A 64 mg (51 µmol) amount of [9th][PF6]2 was dissolved
in 5 mL of pyridine. The solution was degassed and refluxed under
argon for 2 h. Precipitation was obtained by addition of KPF6 at
room temperature; the solid was filtered, washed with water, and
1
recovered with acetone. Yield: 66 mg (100%) of [10th][PF6]2. H
500 MHz NMR (δ in ppm in acetone-d6): 9.28 (d, 1H, P7, J ) 1.8
Hz); 9.01 (d, 1H, P9, J ) 1.8 Hz); 8.94 (s, 2H, T3′5′); 8.92 (d, 2H,
T33′′, J ) 8.1 Hz); 8.76 (d, 1H, P4, J ) 8.1 Hz); 8.62 (d, 1H, P6, J
) 8.8 Hz); 8.47 (d, 1H, P5, J ) 8.8 Hz); 8.37 (t, 1H, TA, J ) 1.8
Hz); 8.22 (td, 2H, T44′′, J ) 7.7,1.5 Hz); 8.18 (m, 1H, TE); 8.11
(m, 2H, T66′′); 7.90-7.86 (m, 2H, TC + PYp); 7.81-7.75 (m, 7H,
PYo + Ta + Pa + TD); 7.51 (m, 2H, T55′′); 7.43 (d, 1H, P3, J ) 8.1
Hz); 7.32 (dd, 2H, PYm); 7.12 (d, 2H, Tb, J ) 8.8 Hz); 7.10 (d,
Characterization of [11th][PF6]2. 1H 500 MHz NMR (δ in ppm
in acetone-d6): 11.04 (d, 1H, P9, J ) 2.1 Hz); 9.37 (d, 1H, P7, J )
1.9 Hz); 9.06 (s, 2H, T3′5′); 8.96 (d, 2H, T33′′, J ) 7.6 Hz); 8.81 (d,
1H, P4, J ) 8.3 Hz); 8.60 (d, 1H, P6, J ) 8.8 Hz); 8.45-8.42 (m,
2H, P5 + TA); 8.33-8.23 (m, 3H, T44′′ + TE); 8.18 (m, 2H, T66′′);
Inorganic Chemistry, Vol. 46, No. 25, 2007 10529

Bonnet et al.
8.10 (d, 2H, Ta, J ) 9.1 Hz); 7.96 (m, 1H, TC); 7.85-7.81 (m, 3H,
TD + Pa); 7.55 (m, 2H, T55′′); 7.46 (d, 1H, P3, J ) 8.1 Hz); 7.26 (d,
2H, Tb, J ) 9.1 Hz); 7.14 (d, 2H, Pb, J ) 9.1 Hz); 6.62 (s, 2H,
Pm); 3.94 (s, 3H, TMeO); 3.90 (s, 3H, PMeO); 1.17 (s, 6H, Me°). Mep
is hidden behind the residual solvent peak. ES MS m/z (calcd):
460.633 (460.631, [M - CH3SOCH3 - 2PF6]2+); 499.643 (499.638,
[M - 2PF6]2+); 1144.244 (1144.241, [M - PF6]+). UV-vis (λmax
in DMSO): 437 nm (S-bonded); 490 nm (O-bonded).
122+. A 51 mg (39 µmol) amount of 10[PF6]2 was weighed in a
Schlenk flask, put under argon, dissolved with 3 mL of dry
dichloromethane, and cooled to -78 °C. A 1.40 mL (1.40 mmol)
amount of 1 M boron tribromide in DCM was added via a syringe
at -78 °C. The mixture was stirred for 1.5 h at -78 °C and 1 h at
15 °C. A 2 mL amount of water and 2 mL of acetone were added,
the solution was stirred at RT for 5 min, the organic solvents were
evaporated, acetone was added, and the complex was precipitated
with KPF6. The solid was filtered, washed with water, and recovered
with acetone. Yield of 12[PF6]2: 50 mg (100%).
2H, Tb, J ) 8.8 Hz); 7.10 (d, 2H, Pb, J ) 8.8 Hz); 6.63 (s, 2H,
Pm); 5.87-5.76 (m, 2H, ιT + ιP); 5.02-4.89 (m, 4H, κT + κP);
4.11 (t, 2H, RT, J ) 6.6 Hz); 4.07 (t, 2H, RP, J ) 6.6 Hz); 2.05-
2.03 (m, 4H, θT + θP); 2.03 (s, 3H, Mep); 1.85-1.78 (m, 4H, âT
+âP);1.54-1.47(m,4H,γT +γP);1.45-1.28(m,δTδPꢀTꢀPúTúPηTηP);
0.98 (s, 6H, Me°). ES MS m/z (calcd): 624.29 (624.28, [M -
2PF6]2+). UV-vis (λmax (ꢀ in L mol-1 cm-1) in acetone): 486 nm
(15 900).
Characterization of 13photo2+,2PF6-. 1H NMR 500 MHz (δ (ppm)
in acetone-d6): 9.13 (s, 2H, T3′5′); 9.12 (d, 1H, P4, J ) 7.8 Hz);
8.90 (d, 2H, T33′′, J ) 7.8 Hz); 8.77 (d, 1H, P7, J ) 2.0 Hz); 8.57
(d, 1H, P5, J ) 9.0 Hz); 8.37 (d, 1H, P6, J ) 8.4 Hz); 8.30-8.28
(m, 3H, TA + T66′′); 8.19 (td, 2H, T44′′, J ) 7.8,1.5 Hz); 8.07 (d,
1H, P3, J ) 8.4 Hz); 8.03 (m, 1H, TE); 8.02 (d, 2H, P9, J ) 2.0
Hz); 7.84 (d, 1H, TC, J ) 8.5 Hz); 7.73 (d, 2H, Ta, J ) 9.0 Hz);
7.70 (t, 1T, TD, J ) 7.8 Hz); 7.59 (t, 1H, PYp, J ) 7.8 Hz); 7.55
(m, 2H, T55”); 7.29 (d, 2H, Pa, J ) 8.4 Hz); 7.27 (d, 2H, PYo, J )
5.4 Hz); 7.08 (d, 2H, Tb, J ) 8.4 Hz); 6.86 (d, 2H, Pb, J ) 8.4
Hz); 6.85 (t, 2H, PYm, J ) 7.2 Hz); 6.43 (s, 2H, Pm); 5.86-5.74
(m, 2H, ιP + ιT); 5.02-4.87 (m, 4H, κP + κT); 4.08 (t, 2H, RT, J )
6.6 Hz); 3.92 (t, 2H, RP, J ) 6.4 Hz); 2.16 (s, 6H, Me°); 2.03 (s,
3H, Mep); 2.03-1.95 (m, 4H, θT + θP); 1.82 (q, 2H, âT, J ) 6.6
Hz); 1.69 (q, 2H, âP, J ) 6.6 Hz); 1.52 (q, 2H, γT, J ) 7.3 Hz);
1.44-1.26 (m, 18H, γPꢀTꢀPδTδPúTúPηTηP). ES MS m/z (calcd):
624.2772 (624.2772, [M - 2PF6]2+). UV-vis (λmax (ꢀ in L mol-1
cm-1) in acetone): 481 nm (11 000).
14th2+. A 35 mg (28 µmol) amount of [12th][PF6]2 was weighed
in a 50 mL flask. A 38 mg (280 µmol) amount of potassium
carbonate, 140 mg (560 µmol) of (2(2-bromoethoxy)ethoxy)ethyl
allyl ether, and 10 mL of dimethylformamide were added; the
reaction flask was put under argon and stirred at 60 °C for 8 h.
DMF was removed under vacuum, acetone was added, and the
complex was precipitated by addition of KPF6. The complex was
filtered, washed with water, recovered with acetone, and purified
over 200 mL of fine silica gel (eluent acetone/water/KNO3 100:5:
0.1). Yield: 39 mg (87%). 1H NMR 500 MHz (δ (ppm) in acetone-
d6): 9.30 (d, 1H, P7, J ) 1.8 Hz); 9.07 (d, 1H, P9, J ) 1.8 Hz);
8.96 (s, 2H, T3′5′); 8.94 (d, 2H, T33′′, J ) 8.1 Hz); 8.77 (d, 1H, P4,
J ) 8.1 Hz); 8.62 (d, 1H, P6, J ) 8.8 Hz); 8.48 (d, 1H, P5, J ) 8.8
Hz); 8.37 (s, 1H, TA); 8.24 (td, 2H, T44′′, J ) 7.7,1.5 Hz); 8.17 (m,
1H, TE); 8.13 (m, 2H, T66′′); 7.90-7.87 (m, 2H, TD + PYp); 7.83
(m, 1H, TC); 7.80-7.74 (m, 6H, PYo + Ta + Pa); 7.51 (m, 2H,
Characterization of 12th2+,2PF6-. 1H NMR 500 MHz (δ (ppm)
in acetone-d6): 9.26 (d, 1H, P7, J ) 1.8 Hz); 9.00 (d, 1H, P9, J )
1.8 Hz); 8.96 (s, 2H, T3′5′); 8.95 (d, 2H, T33′′, J ) 8.1 Hz); 8.77 (d,
1H, P4, J ) 8.1 Hz); 8.62 (d, 1H, P6, J ) 8.8 Hz); 8.48 (d, 1H, P5,
J ) 8.8 Hz); 8.33 (s, 1H, TA); 8.24 (td, 2H, T44′′, J ) 7.7,1.5 Hz);
8.15-8.13 (m, 3H, TE + T66′′); 7.90 (td, 1H, PYp); 7.85 (m, 1H,
TC); 7.79 (d, 2H, PYo, J ) 5.1 Hz); 7.75 (t, 1H, TD); 7.70 (d, 2H,
Ta, J ) 8.8 Hz); 7.66 (d, 2H, Pa, J ) 8.4 Hz); 7.52 (m, 2H, T55′′);
7.44 (d, 1H, P3, J ) 8.1 Hz); 7.33 (dd, 2H, PYm); 7.03 (d, 2H, Tb,
J ) 8.8 Hz); 7.01 (d, 2H, Pb, J ) 8.8 Hz); 6.63 (s, 2H, Pm); 2.03
(s, 3H, Mep); 0.99 (s, 6H, Me°). UV-vis (λmax (ꢀ in L mol-1 cm-1
)
in acetone): 485.5 nm (7390). ES MS m/z (calcd): 486.137
(486.136, [M - 2PF6]2+).
Characterization of 12photo2+,2PF6-. 1H NMR 500 MHz (δ (ppm)
in CD2Cl2): 8.84 (d, 1H, P4, J ) 7.8 Hz); 8.55 (s, 2H, T3′5′); 8.51
(d, 2H, T33′′, J ) 7.8 Hz); 8.36 (d, 1H, P7, J ) 2.0 Hz); 8.35 (d,
1H, P5, J ) 9.0 Hz); 8.17 (d, 1H, P6, J ) 8.4 Hz); 8.07 (td, 2H,
T44′′, J ) 7.8,1.5 Hz); 8.02 (m, 1H, TA, J ) 1.5 Hz); 7.88 (d, 1H,
P3, J ) 8.4 Hz); 7.84 (m, 3H, TE + T66′′); 7.72 (m, 1H, TC); 7.65-
7.63 (m, 2H, TD + P9); 7.61 (d, 2H, Ta, J ) 9.0 Hz); 7.42-7.38
(m, 3H, T55′′ + PYp); 7.09 (d, 2H, Pa, J ) 8.4 Hz); 6.94 (d, 2H, Tb,
J ) 8.4 Hz); 6.92 (d, 2H, PYo, J ) 5.4 Hz); 6.81 (d, 2H, Pb, J )
8.4 Hz); 6.68 (dd, 2H, PYm); 6.38 (s, 2H, Pm); 6.09 (s, 1H, OHT);
5.63 (s, 1H, OHP); 2.02 (s, 6H, Me°); 2.01 (s, 3H, Mep). ES MS
m/z (calcd): 486.16 (486.14, [M - 2PF6]2+). UV-vis (λmax (ꢀ in
L mol-1 cm-1) in acetone): 481 nm (11 000).
T55′′); 7.44 (d, 1H, P3, J ) 8.1 Hz); 7.32 (dd, 2H, PYm); 7.14 (d,
2H, Tb, J ) 8.8 Hz); 7.12 (d, 2H, Pb, J ) 8.8 Hz); 6.63 (s, 2H,
Pm); 5.94-5.84 (m, 2H, θT + θP); 5.28-5.22 (m, 2H, cis-ιT + ιP);
5.12-5.08 (m, 2H, trans- ιT + ιP); 4.25-4.20 (m, 4H, RT + RP);
4.00-3.96 (m, 4H, ηT + ηP); 3.89-3.83 (m, 4H, âT + âP); 3.71-
3.55 (m, 16H, γTγPδTδPꢀTꢀPúTúP); 2.04 (s, 3H, Mep); 0.99 (s, 6H,
Me°). ES MS m/z (calcd): 658.246 (658.247, [M-2PF6]2+). UV-
vis (λmax (ꢀ in L mol-1 cm-1) in acetone): 486 nm (12 000).
14photo2+. A 50.4 mg (40 µmol) amount of [12photo][PF6]2, 63
mg (456 µmol) of K2CO3, and 107 mg (422 mmol) of (2(2-
bromoethoxy)ethoxy)ethyl allyl ether were weighed in a flask. An
8 mL amount of dimethylformamide was added; the reaction
mixture was put under argon and stirred at 60 °C for 8 h. DMF
was removed by high vacuum; acetone was added followed by KPF6
until precipitation occurred. The complex was filtered, washed with
water, recovered with acetone, dried, and purified over silica gel
(eluent acetone/water/KNO3 100:5:0.1). The main fraction was
precipitated by KPF6, washed with water, recovered with acetone,
and dried to afford 58.3 mg of precursor [14photo][PF6]2 (91%). 1H
NMR 500 MHz (δ (ppm) in acetone-d6): 9.15 (s, 2H, T3′5′); 9.13
(d, 1H, P4, J ) 8.0 Hz); 8.91 (d, 2H, T33′′, J ) 8.1 Hz); 8.79 (d,
132+. A 53 mg (42 µmol) amount of 12[PF6]2 (either thermal or
photochemical isomer) was weighed in a 50 mL flask. A 79 mg
(570 µmol) amount of potassium carbonate, 174 mg (794 µmol)
of 10-bromoundec-1-ene, and 10 mL of dimethylformamide were
added; the reaction flask was put under argon and stirred at 60 °C
for 8 h. DMF was removed under vacuum, acetone was added,
and the complex was precipitated by addition of KPF6. The complex
was filtered, washed with water, recovered with acetone, precipi-
tated with diethyl ether, filtered, and washed with diethyl ether in
order to remove the excess of the chain. The complex was recovered
with acetone and dried. Yield of 13[PF6]2: 65 mg (>99%).
Characterization of 13th2+,2PF6-. 1H NMR 500 MHz (δ (ppm)
in acetone-d6): 9.27 (d, 1H, P7, J ) 1.8 Hz); 9.00 (d, 1H, P9, J )
1.8 Hz); 8.93 (s, 2H, T3′5′); 8.92 (d, 2H, T33′′, J ) 8.1 Hz); 8.75 (d,
1H, P4, J ) 8.1 Hz); 8.61 (d, 1H, P6, J ) 8.8 Hz); 8.47 (d, 1H, P5,
J ) 8.8 Hz); 8.37 (s, 1H, TA); 8.22 (td, 2H, T44′′, J ) 7.7,1.5 Hz);
8.17 (m, 1H, TE); 8.11 (m, 2H, T66′′); 7.90-7.86 (m, 2H, TC
PYp); 7.80-7.74 (m, 7H, PYo + Ta + Pa + TD); 7.51 (m, 2H,
55′′); 7.42 (d, 1H, P3, J ) 8.1 Hz); 7.32 (dd, 2H, PYm); 7.12 (d,
+
T
10530 Inorganic Chemistry, Vol. 46, No. 25, 2007

Acyclic Ruthenium(II) Complexes
1H, P9, J ) 1.8 Hz); 8.58 (d, 1H, P5, J ) 8.8 Hz); 8.39 (d, 1H, P6,
J ) 8.8 Hz); 8.31 (m, 2H, T66”); 8.29 (t, 1H, TA, J ) 1.8 Hz); 8.20
(td, 2H, T44′′, J ) 7.7,1.5 Hz); 8.09 (d, 1H, P3, J ) 8.1 Hz); 8.04
(d, 1H, P9, J ) 2.0 Hz); 8.03 (m, 1H, TE); 7.86 (m, 1H, TC); 7.74
(d, 2H, Ta, J ) 8.9 Hz); 7.71 (m, 1H, TD); 7.59 (tt, 1H, PYp, J )
7.7,1.5 Hz); 7.55 (m, 2H, T55′′); 7.31 (d, 2H, Pa, J ) 8.9 Hz); 7.28
(m, 2H, PYo); 7.11 (d, 2H, Tb, J ) 8.9 Hz); 6.89 (d, 2H, Pb, J )
8.8 Hz); 6.85 (m, 2H, PYm); 6.43 (s, 2H, Pm); 5.93-5.80 (m, 2H,
θT + qP); 5.26 (ddd, 1H, trans-ιT, J ) 17.3,3.8,1.7 Hz); 5.20 (ddd,
1H, trans-ιP, J ) 17.3,3.8,1.7 Hz); 5.10 (ddd, 1H, cis-ιT, J )
10.5,2.1,1.5 Hz); 5.05 (ddd, 1H, cis-ιP, J ) 10.5,2.1,1.5 Hz); 4.22
(m, 2H, RT); 4.06 (m, 2H, RP); 3.99 (m, 2H, ηT); 3.93 (m, 2H, ηP);
3.87 (m, 2H, âT); 3.75 (m, 2H, âP); 3.69 (m, 2H, γT); 3.64 (m, 2H,
δT); 3.62 (m, 2H, ꢀT); 3.59 (m, 2H, γP); 3.57 (m, 2H, úT); 3.56 (m,
2H, δP); 3.54 (m, 2H, ꢀP); 3.51 (m, 2H, úP); 2.16 (s, 6H, Me°);
2.03 (s, 3H, Mep). ES MS m/z (calcd): 658.2470 (658.2468, [M -
2PF6]2+); 1461.451 (1461.458, [M - PF6]+). UV-vis (λmax (ꢀ in
L mol-1 cm-1) in acetone): 481.5 nm (12 800).
15th2+. A 17 mg amount of [13th][PF6]2 and 13 mg of Grubbs’
first-generation catalyst were dissolved in dichloromethane and
stirred under argon in the dark for 7 days. Acetone was added along
with aqueous potassium hexafluorophosphate, and removal of the
organic solvents led to precipitation of the complex. The solid was
filtered, washed with water, and recovered with acetone. Chroma-
tography over silica gel (acetone/water/KNO3 100:5:0.1 to 60:5:1)
was undertaken in order to separate, in this order, the remaining
starting material, the monomer [15th][PF6]2 (3.6 mg, 21%), and the
dimer (4.3 mg, 25% yield). ES MS m/z (calcd): for the monomer
610.31 (610.26, [M - 2PF6]2+); for the dimer 610.31 (610.26, [M
- 4PF6]4+); 862.06 (862.00, [M - 3PF6]3+); 1365.6 (1365.5, [M
- 2PF6]2+).
to remove ethylene. The DCM was evaporated, acetone was added,
and the complex was precipitated with KPF6, filtered, washed with
water, recovered with acetone, and purified over 200 mL of fine
silica gel (eluent, acetone/water/KNO3 80:5:0.5). Yield: 115 mg
of [15photo][PF6]2 (71%). 1H NMR 500 MHz (δ (ppm) in acetone-
d6): 9.13 (s, 2H, T3′5′); 9.12 (d, 1H, P4, J ) 7.8 Hz); 8.90 (d, 2H,
T
33′′, J ) 7.8 Hz); 8.77 (d, 1H, P7, J ) 2.0 Hz); 8.57 (d, 1H, P5, J
) 9.0 Hz); 8.37 (d, 1H, P6, J ) 8.4 Hz); 8.30-8.28 (m, 3H, TA +
66′′); 8.19 (td, 2H, T44′′, J ) 7.8,1.5 Hz); 8.07 (d, 1H, P3, J ) 8.4
T
Hz); 8.03 (m, 1H, TE); 8.02 (d, 2H, P9, J ) 2.0 Hz); 7.84 (d, 1H,
TC, J ) 8.5 Hz); 7.73 (d, 2H, Ta, J ) 9.0 Hz); 7.70 (t, 1H, TD, J
) 7.8 Hz); 7.59 (t, 1H, PYp, J ) 7.8 Hz); 7.55 (m, 2H, T55′′); 7.29
(d, 2H, Pa, J ) 8.4 Hz); 7.27 (d, 2H, PYo, J ) 5.4 Hz); 7.08 (d,
2H, Tb, J ) 8.4 Hz); 6.86 (d, 2H, Pb, J ) 8.4 Hz); 6.85 (t, 2H,
PYm, J ) 7.2 Hz); 6.43 (s, 2H, Pm); 5.86-5.74 (m, 2H, ιP + ιT);
5.02-4.87 (m, 4H, κP + κT); 4.08 (t, 2H, RT, J ) 6.6 Hz); 3.92 (t,
2H, RP, J ) 6.4 Hz); 2.16 (s, 6H, Me°); 2.03 (s, 3H, Mep). UV-
vis (λmax (ꢀ in L mol-1 cm-1) in acetone): 481 nm. ES MS m/z
(calcd): 610.27 (610.26, [M - 2PF6]2+); 1365.51 (1365.49, [M -
PF6]+).
16photo2+. A 50 mg (31 µmol) amount of [14photo][PF6]2 and 10
mg (12 µmol) of Grubbs’ first-generation catalyst were weighed
in a 100 mL flask and put under argon. A 50 mL amount of dry
dichloromethane was cannulated, and the solution was stirred in
the dark at room temperature for 60 h. During the course of the
reaction the solution was flushed three times with argon in order
to remove ethylene. The DCM was evaporated, acetone was added,
and the complex was precipitated with KPF6, filtered, washed with
water, recovered with acetone, and purified over 180 mL of silica
gel (eluent, acetone/water/KNO3 100:5:0.1 to 80:5:0.5). Yield: 41
mg of [16photo][PF6]2 (83%). 1H NMR 500 MHz (δ (ppm) in
acetone-d6): 9.15 (s, 2H, T3′5′); 9.13 (d, 1H, P4, J ) 7.8 Hz); 8.91
(d, 2H, T33′′, J ) 7.8 Hz); 8.78 (d, 1H, P7, J ) 2.0 Hz); 8.58 (d,
1H, P5, J ) 9.0 Hz); 8.38 (m, 2H, TA + P6); 8.31 (d, 2H, T66′′, J
) 5.5 Hz); 8.20 (td, 2H, T44′′, J ) 7.8,1.5 Hz); 8.09 (d, 1H, P3, J
) 8.4 Hz); 7.98 (d, 2H, P9, J ) 2.0 Hz); 7.97 (m, 1H, TE); 7.85 (d,
1H, TC, J ) 8.5 Hz); 7.77 (d, 2H, Ta, J ) 9.0 Hz); 7.69 (m, 1H,
TD); 7.60 (t, 1H, PYp); 7.55 (m, 2H, T55′′); 7.30 (d, 2H, Pa, J ) 8.4
Hz); 7.28 (d, 2H, PYo, J ) 5.4 Hz); 7.13 (d, 2H, Tb, J ) 8.4 Hz);
6.87 (d, 2H, Pb, J ) 8.4 Hz); 6.86 (m, 2H, PYm); 6.44 (s, 2H, Pm);
5.76 (m, 69% of 2H, θP + θT); 5.62 (m, 31% of 2H, θP + θT);
4.23 (m, 2H, RT); 4.03 (m, 2H, RP); 3.99 (m, 2H, ηT); 3.93 (m, 2H,
ηP); 3.88 (m, 2H, âT); 3.72 (m, 2H, âP); 3.69 (m, 2H, γT); 3.63 (m,
2H, δT); 3.62 (m, 2H, γP); 3.57 (m, 2H, δP); 3.56-3.52 (m, 6H, ꢀT
+ úT + ꢀP); 3.49 (m, 2H, úP); 2.17 (s, 6H, Me°); 2.03 (s, 3H, Mep).
ES MS m/z (calcd): 644.22 (644.23, [M - 2PF6]2+); 1433.39
(1433.43, [M - PF6]+). UV-vis (λmax (ꢀ in L mol-1 cm-1) in
acetone): 479.5 nm (13 200).
17th2+. A 16 mg (11 µmol) amount of [17photo][PF6]2 was
dissolved in 4 mL of distilled DMSO, put under argon, and heated
in the dark at 140 °C for 2 h. The complex was precipitated with
KPF6, filtered, washed with water, recovered with acetone, and
dried. A 4 mL amount of pyridine was added; the solution was
flushed with argon and refluxed for 2 h under argon. KPF6 was
added until complete precipitation; the solid was filtered, washed
with water, recovered with acetone, and dried. Column chroma-
tography on 80 mL of silica gel (eluent, acetone/water/KNO3 80:
5:0.5) yielded 13 mg of [17th][PF6]2 (85%). 1H NMR 500 MHz (δ
(ppm) in CD2Cl2): 8.90 (d, 1H, P7, J ) 1.8 Hz); 8.49 (d, 1H, P4,
J ) 8.1 Hz); 8.44 (d, 3H, P6 + T33′′); 8.40 (d, 1H, P9, J ) 1.8 Hz);
16th2+. A 31 mg (19 µmol) amount of [14th][PF6]2 and 13 mg
(16 µmol) of Grubbs’ first-generation catalyst were weighed in a
flask and put under argon. A 100 mL amount of dry dichlo-
romethane was added in the dark, and the solution was stirred for
5 days and flushed with argon regularly. The DCM was removed
under vacuum, acetone was added, and the complex was precipitated
with KPF6, filtered, washed with water, recovered with acetone,
and put on 200 mL of fine silica gel for purification (eluent, acetone/
water/KNO3 80:5:0.3). The monomer was the less polar fraction
and the dimer the most polar. Yield: 8.1 mg of the monomer [16th]-
1
[PF6]2 (26%) and 8.7 mg for the corresponding dimer (28%). H
NMR 500 MHz (δ (ppm) in acetone-d6): 9.26 (d, 1H, P7, J ) 1.8
Hz); 8.91 (d, 2H, T33′′, J ) 8.1 Hz); 8.84 (s, 2H, T3′5′); 8.81 (d, 1H,
P9, J ) 1.8 Hz); 8.80 (d, 1H, P4, J ) 8.1 Hz); 8.63 (d, 1H, P6, J )
8.8 Hz); 8.50 (d, 1H, P5, J ) 8.8 Hz); 8.24 (td, 2H, T44′′, J ) 7.7,1.5
Hz); 8.19 (m, 1H, TE); 8.08 (m, 2H, T66′′); 7.95 (s, 1H, TA); 7.89-
7.85 (m, 2H, TC + PYp); 7.78 (m, 1H, TD); 7.73 (d, 2H, PYo, J )
5.5 Hz); 7.68 (d, 2H, Ta, J ) 9.0 Hz); 7.66 (d, 2H, Pa, J ) 9.0 Hz);
7.53-7.49 (m, 3H, P3 + T55′′); 7.29 (dd, 2H, PYm); 7.14 (d, 2H,
Tb, J ) 8.8 Hz); 7.13 (d, 2H, Pb, J ) 8.8 Hz); 6.67 (s, 2H, Pm);
5.66 (m, 2H, θT + θP); 4.28 (m, 4H, RT + RP); 3.87 (m, 4H, ηT +
ηP); 3.80,3.76 (m, 2 × 2H, âT and âP); 3.62 (m, 2H, γT); 3.56 (m,
2H, γP); 3.55 (m, 2H, δT); 3.50 (m, 2H, δP); 3.49 (m, 2H, ꢀT); 3.46
(m, 2H, ꢀP); 3.46 (m, 2H, úT); 3.43 (m, 2H, úP); 2.14 (s, 3H, Mep);
0.95 (s, 6H, Me°). ES MS m/z (calcd): 644.2317 (644.2311, [M -
2PF6]2+); 1433.44 (1433.43, [M - PF6]+).
15photo2+. A 157 mg (102 µmol) amount of [13photo][PF6]2 and
35 mg (42 µmol) of Grubbs’ first-generation catalyst were weighed
in a 100 mL flask and put under argon. A 150 mL amount of dry
dichloromethane was cannulated, and the solution was stirred in
the dark at room temperature for 36 h. During the course of the
reaction the solution was flushed three times with argon in order
8.28 (d, 1H, P5, J ) 8.8 Hz); 8.21 (s, 2H, T3′5′); 8.10 (td, 2H, T44′′
,
J ) 7.7,1.5 Hz); 7.88 (m, 1H, TE); 7.79 (m, 1H, TC); 7.74 (m, 1H,
TD); 7.67-7.63 (m, 6H, Ta + T66′′ + TA + PYp); 7.50 (d, 2H, Pa,
Inorganic Chemistry, Vol. 46, No. 25, 2007 10531

Bonnet et al.
J ) 8.8 Hz); 7.42 (m, 2H, T55′′); 7.32 (d, 2H, PYo, J ) 5 Hz); 7.29
(d, 1H, P3, J ) 8.1 Hz); 7.18 (m, 2H, PYm); 7.01 (d, 2H, Tb, J )
8.8 Hz); 6.99 (d, 2H, Pb, J ) 8.8 Hz); 6.59 (s, 2H, Pm); 4.09 (t,
2H, RT, J ) 6.6 Hz); 4.07 (t, 2H, RP, J ) 7.0 Hz); 2.17 (s, 3H,
Mep); 1.73 (m, 4H, âT + âP); 1.37 (4H, γT + γP); 1.34-1.18 (m,
24H, δT - ιT + δP - ιP); 0.83 (s, 6H, Me°). HR ES MS m/z
(calcd): 611.2676 (611.2688, [M - 2PF6]2+).
Hz); 7.45-7.41 (m, 3H, T55′′ + PYp); 7.16 (d, 2H, Pa, J ) 8.4 Hz);
7.09 (d, 2H, Tb, J ) 8.4 Hz); 6.93-6.90 (d, 4H, PYo + Pb); 6.70
(t, 2H, PYm, J ) 7.2 Hz); 6.39 (s, 2H, Pm); 4.21 (m, 2H, RT); 4.02
(m, 2H, RP); 3.87 (m, 2H, âT); 3.74 (m, 2H, âP); 3.71-3.69 (m,
2H, γT); 3.65-3.63 (m, 2H, δT); 3.61-3.58 (m, 4H, γP + ꢀT); 3.57-
3.52 (m, 6H, δP + úT + ꢀP); 3.50 (m, 2H, úP); 3.43 (m, 2H, ηT);
3.42 (m, 2H, ηP); 2.03 (s, 6H, Me°); 2.02 (s, 3H, Mep); 1.60 (m,
4H, θT + θP). UV-vis (λmax (ꢀ in L mol-1 cm-1) in acetone): 479.5
nm (11 600). HD ES MS m/z (calcd): 645.2391 (645.2389, [M -
2PF6]2+).
17photo2+. A 50 mg (33 mol) amount of the unsaturated macro-
cycle [15photo][PF6]2 and 14 mg of 10% palladium black on carbon
were weighed in a flask and dissolved with 8 mL of dichlo-
romethane and 5 mL of ethanol. The solution was saturated with
hydrogen by 5 min of bubbling and stirred under a hydrogen
atmosphere in the dark for 24 h. The reaction mixture was filtered
on celite to remove the catalyst, and solvents were evaporated.
19photo2+. A 3.6 mg (2.4 µmol) amount of [17photo][PF6]2
was dissolved in 1 mL of 3,5-dimethylpyridine, put under argon,
and heated in the dark at 140 °C for 2 h. The complex was
precipitated with heptane, filtered, washed with heptane, recovered
1
1
Yield: 50 mg of [17photo][PF6]2 (100%). H NMR 500 MHz (δ
with acetone, and dried to give quantitatively [19photo][PF6]2. H
(ppm) in CD2Cl2): 8.85 (d, 1H, P4, J ) 7.8 Hz); 8.57 (s, 2H, T3′5′);
8.52 (d, 2H, T33′′, J ) 7.8 Hz); 8.41 (d, 1H, P7, J ) 2.0 Hz); 8.37
(d, 1H, P5, J ) 9.0 Hz); 8.19 (d, 1H, P6, J ) 8.4 Hz); 8.14 (s, 1H,
TA); 8.10 (td, 2H, T44′′, J ) 7.8,1.5 Hz); 7.89 (d, 1H, P3, J ) 8.4
Hz); 7.85 (m, 2H, T66′′); 7.81-7.79 (m, 2H, TC + TE); 7.73 (d,
2H, Ta, J ) 9.0 Hz); 7.67 (t, 1H, TD, J ) 7.8 Hz); 7.65 (d, 2H, P9,
J ) 2.0 Hz); 7.43 (m, 2H, T55′′); 7.40 (t, 1H, PYp, J ) 7.8 Hz);
7.16 (d, 2H, Pa, J ) 8.4 Hz); 7.06 (d, 2H, Tb, J ) 8.4 Hz); 6.92 (d,
2H, PYo, J ) 5.4 Hz); 6.88 (d, 2H, Pb, J ) 8.4 Hz); 6.69 (t, 2H,
PYm, J ) 7.2 Hz); 6.39 (s, 2H, Pm); 4.06 (t, 2H, RT, J ) 6.6 Hz);
3.86 (t, 2H, RP, J ) 6.4 Hz); 2.03 (s, 6H, Me°); 2.02 (s, 3H, Mep);
1.82 (q, 2H, âT, J ) 6.6 Hz); 1.70 (q, 2H, âP, J ) 6.6 Hz); 1.55-
1.47 (m, 2H, γT); 1.42-1.23 (m, 26H, γP - ιP + δT - ιT). ES MS
m/z (calcd): 1367.3 (1367.5, [M - PF6]+). UV-vis (λmax (ꢀ in L
mol-1 cm-1) in acetone): 481 nm (10 700).
NMR 300 MHz (δ (ppm) in acetone-d6): 9.15 (s, 2H, T3′5′); 9.13
(d, 1H, P4); 8.92 (d, 2H, T33′′); 8.79 (d, 1H, P7); 8.59 (d, 1H, P5);
8.39 (d, 1H, P6); 8.37 (s, 1H, TA); 8.31 (m, 2H, T66′′); 8.22 (td, 2H,
T44′′); 8.07 (d, 1H, P3); 8.03 (d, 2H, P9); 7.97 (m, 1H, TC); 7.86
(m, 1H, TE); 7.78 (d, 2H, Ta); 7.69 (m, 1H, TD); 7.56 (m, 2H, T55′′);
7.31 (d, 2H, Pa); 7.22 (s, 1H, Lp); 7.10 (d, 2H, Tb); 6.85 (d, 2H,
Pb); 6.74 (s, 2H, Lo); 6.53 (s, 2H, Pm); 4.11 (t, 2H, RT); 3.89 (t,
2H, RP); 2.18 (s, 6H, Me°); 2.02 (s, 3H, Mep); 1.84 (s, 6H, LCH3);
1.68 (m, 2H, âT); 1.52 (m, 2H, âP); 1.45-1.23 (m, 28H, γP - ιP +
γT - ιT).
20photo2+. A 3.6 mg (2.4 µmol) amount of [17photo][PF6]2 was
dissolved in 1 mL of benzonitrile, put under argon, and heated in
the dark at 140 °C for 2 h. The complex was precipitated with
heptane, filtered, washed with heptane, recovered with acetone, and
1
dried to give quantitatively [20photo][PF6]2. H NMR 300 MHz (δ
18th2+. A 8 mg (5 µmol) amount of [16th][PF6]2 was weighed
along with 7 mg of 10% palladium black on carbon. A 2 mL amount
of ethanol and 4 mL of dichloromethane were added; the mixture
was saturated with hydrogen in 5 min of bubbling and stirred for
24 h at room temperature in the dark under a 1 atm hydrogen
pressure. The catalyst was removed by filtration of the reaction
mixture on celite, the solvents were evaporated, and the product
was purified by chromatography on 90 mL of fine silica gel (eluent,
acetone/water/KNO3 80:5:0.5). The main fraction contained 7 mg
(87%) of the reduced macrocycle [18th][PF6]2. 1H NMR 500 MHz
(δ (ppm) in CD2Cl2): 8.91 (d, 1H, P7, J ) 1.8 Hz); 8.49 (d, 1H, J
) 8.1 Hz); 8.46-8.43 (m, 4H, T33′′ + P6 + P4); 8.37 (d, 1H, P9, J
) 1.8 Hz); 8.28 (d, 1H, P5, J ) 8.8 Hz); 8.23 (s, 2H, T3′5′); 8.11 (t,
2H, T44′′, J ) 7.7 Hz); 7.92 (m, 1H, TE); 7.80 (m, 1H, TC); 7.76
(m, 1H, TD); 7.72 (s, 1H, TA); 7.70 (m, 1H, PYp); 7.65 (m, 4H, Ta
+ T66′′); 7.51 (d, 2H, Pa, J ) 9.0 Hz); 7.43 (m, 2H, T55′′); 7.28 (m,
3H, P3 + PYo); 7.17 (m, 2H, PYm); 7.08 (d, 2H, Tb, J ) 8.8 Hz);
7.07 (d, 2H, Pb, J ) 8.8 Hz); 6.59 (s, 2H, Pm); 4.23 (m, 4H, RT +
RP); 3.78 (m, 4H, âT + âP); 3.63-3.46 (m, 20H, γT + γP + δT +
δP + ꢀT + ꢀP + úT + úP); 3.36 (m, 4H, ηT + ηP); 2.16 (s, 3H,
Mep); 1.53 (m, 4H, θT + θP); 0.84 (s, 6H, Me°). HD ES MS m/z
(calcd): 645.236 (645.238, [M - 2PF6]2+).
18photo2+. A 6 mg amount of [18th][PF6]2 was dissolved in 2 mL
of pyridine and irradiated for 1 h at room temperature with a Xenon
1000 W arc lamp filtered by a water filter. The complex was
precipitated by addition of KPF6, filtered, washed with water,
recovered with acetone, and dried. Yield of [18photo][PF6]2: 100%.
1H NMR 500 MHz (δ (ppm) in CD2Cl2): 8.85 (d, 1H, P4, J ) 7.8
Hz); 8.57 (s, 2H, T3′5′); 8.51 (d, 2H, T33′′, J ) 7.8 Hz); 8.42 (d, 1H,
P7, J ) 2.0 Hz); 8.37 (d, 1H, P5, J ) 9.0 Hz); 8.19 (d, 1H, P6, J )
8.4 Hz); 8.10 (td, 3H, T44′′ + TA); 7.90 (d, 1H, P3, J ) 8.4 Hz);
7.86 (m, 2H, T66′′); 7.82-7.79 (m, 2H, TC + TE); 7.71 (d, 2H, Ta,
J ) 9.0 Hz); 7.68 (t, 1H, TD, J ) 7.8 Hz); 7.63 (d, 2H, P9, J ) 2.0
(ppm) in CD2Cl2): 8.86 (d, 1H, P4); 8.71 (s, 2H, T3′5′); 8.58 (d,
2H, T33′′); 8.45 (d, 1H, P7); 8.37 (d, 1H, P5); 8.20 (d, 1H, P6); 8.18
(s, 1H, TA); 8.09 (td, 2H, T44′′); 7.99 (d, 1H, P3); 7.89 (m, 1H, TC);
7.83 (d, 2H, P9); 7.81 (m, 1H, TE); 7.74 (m, 4H, T66′′ + Ta); 7.68
(m, 1H, TD); 7.50 (m, 2H, P3 + Bp); 7.34 (m, 4H, Bo + T55′′); 7.21
(d, 2H, Pa); 7.05 (d, 2H, Tb); 6.90 (m, 4H, Pb + Bm); 6.71 (s, 2H,
Pm); 4.05 (t, 2H, RT); 3.86 (t, 2H, RP); 2.14 (s, 6H, Me°); 1.59 (s,
3H, Mep); 1.81 (m, 2H, âT); 1.69 (m, 2H, âP); 1.53-1.17 (m, 28H,
γP - ιP + γT - ιT). ES-MS m/z (calcd): 623.28 (623.27, [M -
2PF6]2+); 1391.53 (1391.50, [M - PF6]+).
21th2+. A 21 mg (14 µmol) amount of [17photo][PF6]2 was
dissolved in 2 mL of distilled DMSO, put under argon, and heated
in the dark at 140 °C for 2 h. The complex was precipitated with
KPF6, filtered, washed with water, recovered with acetone, and
dried. A 5 mL amount of acetonitrile was added, and the solution
was flushed with argon and refluxed for 2 h under argon and in
the dark. KPF6 was added until complete precipitation, and the solid
was filtered, washed with water, recovered with acetone, and dried.
Column chromatography on 150 mL of silica gel (eluent, acetone/
1
water/KNO3 80:5:0.5) yielded 17 mg of [21th][PF6]2 (84%). H
NMR 500 MHz (δ (ppm) in CD2Cl2): 9.81 (d, 1H, P9, J ) 1.8
Hz); 8.93 (d, 1H, P7, J ) 1.8 Hz); 8.48 (d, 1H, P4, J ) 8.1 Hz);
8.43 (d, 1H, P6); 8.37 (d, 2H, T33′′); 8.26 (s, 2H, T3′5′); 8.23 (d, 1H,
P5, J ) 8.8 Hz); 8.03 (td, 2H, T44′′, J ) 7.7,1.5 Hz); 7.94 (d, 2H,
Pa, J ) 8.8 Hz); 7.90 (m, 1H, TE); 7.84 (m, 2H, TA + TC); 7.78
(m, 1H, TD); 7.69 (d, 2H, Ta); 7.48 (d, 2H, T66′′); 7.30 (m, 3H, P3
+ T55′′); 7.17 (d, 2H, Pb, J ) 8.8 Hz); 7.02 (d, 2H, Tb, J ) 8.8
Hz); 6.58 (s, 2H, Pm); 4.14 (t, 2H, RP, J ) 7.0 Hz); 4.09 (t, 2H, RT,
J ) 6.6 Hz); 2.20 (s, 3H, Mep); 2.07 (s, 3H, ANMe); 1.75 (m, 4H,
âT + âP); 1.39 (4H, γT + γP); 1.30-1.10 (m, 24H, δT - ιT + δP
- ιP); 0.85 (s, 6H, Me°). HR ES MS m/z (calcd): 1329.490
(1329.488, [M - PF6]+). UV-vis (λmax (ꢀ in L mol-1 cm-1) in
acetone): 462 nm (14 700).
10532 Inorganic Chemistry, Vol. 46, No. 25, 2007

Acyclic Ruthenium(II) Complexes
22th2+. A 25 mg (17 µmol) amount of [17photo][PF6]2 was
dissolved in 4 mL of distilled DMSO, put under argon, and heated
in the dark at 140 °C for 2 h. The complex was precipitated with
KPF6, filtered, washed with water, recovered with acetone, and
dried. A 50 mg amount of tetraethylammonium chloride and 10
mL of acetone were added; the solution was put under argon,
refluxed for 3 h, and let cool to room temperature overnight. KPF6
was added until complete precipitation; the solid was filtered,
washed with water, recovered with acetone, and dried. Column
chromatography on 160 mL of silica gel (eluent, acetone/water/
66:33 mixture of products analyzed as S-bonded:O-bonded [23th]-
[PF6]2, respectively. After one night at room temperature in the
dark the mixture evolved to a 87:13 ratio, which enabled analysis
1
of the main product (S-bonded [23th][PF6]2). H NMR 300 MHz
(δ (ppm) in DMSO-d6): 10.67 (d, 1H, P9); 9.42 (d, 1H, P7); 8.88
(d, 2H, T33′′); 8.85 (s, 2H, T3′5′); 8.83 (d, 1H, P4); 8.59 (d, 1H, P6);
8.45 (d, 1H, P5); 8.23 (td, 2H, T44′′); 8.21 (m, 1H, TE); 8.01 (m,
3H, Pa + TA); 7.92-7.76 (m, 6H, TC + TD + Ta + T66′′); 7.46 (m,
3H, P3 + T55′′); 7.26 (d, 2H, Pb); 7.10 (d, 2H, Tb); 6.53 (s, 2H, Pm);
4.18 (m, 4H, RP + RT); 2.13 (s, 3H, Mep); 2.10 (s, 6H, DMSOCH3);
1.68 (m, 4H, âT + âP); 1.42-1.10 (28H, γT - ιT + γP - ιP); 0.94
(s, 6H, Me°). ES-MS m/z (calcd): 571.745 (571.748, [M - DMSO
- 2PF6]2+); 609.74 (610.755, [M - H - 2PF6]2+); 1222.4 (1221.5,
[M - H - PF6]+). UV-vis (λmax in acetone): 438 (S-bonded) and
496 nm (O-bonded).
1
KNO3 80:5:0.5) yielded 23 mg of [22th][PF6]2. Yield: 100%. H
NMR 500 MHz (δ (ppm) in acetone-d6): 10.94 (d, 1H, P9, J )
1.8 Hz); 9.18 (d, 1H, P7, J ) 1.8 Hz); 8.71 (d, 2H, T33′′); 8.66 (s,
2H, T3′5′); 8.62 (d, 1H, P4, J ) 8.1 Hz); 8.57 (d, 1H, P6); 8.40 (d,
1H, P5, J ) 8.8 Hz); 8.13 (m, 1H, TE); 8.02-7.95 (m, 5H, T44′′
Pa + TA); 7.83 (m, 1H, TC); 7.78 (m, 1H, TD); 7.73 (m, 4H, Ta +
66′′); 7.37 (d, 1H, P3); 7.25 (m, 2H, T55′′); 7.22 (d, 2H, Pb, J ) 8.8
+
T
Acknowledgment. We thank the CNRS for financial
support. The Re´gion Alsace is also gratefully acknowledged
for a fellowship to S.B. We also thank Johnson Matthey Inc.
for a loan of RuCl3.
Hz); 7.06 (d, 2H, Tb, J ) 8.8 Hz); 6.64 (s, 2H, Pm); 4.21 (t, 2H,
RP, J ) 7.0 Hz); 4.16 (t, 2H, RT, J ) 6.6 Hz); 2.20 (s, 3H, Mep);
1.76 (m, 4H, âT + âP); 1.42 (4H, γT + γP); 1.30 (m, 4H, δT + δP);
0.90 (s, 6H, Me°). ES-MS m/z (calcd): 1178.462 (1178.465, [M
- PF6]+). UV-vis (λmax (ꢀ in L mol-1 cm-1) in acetone): 512 nm
(11 600).
23th2+. A 6 mg (4 µmol) amount of [17photo][PF6]2 was put in an
NMR tube and dissolved in deuterated DMSO. The tube was closed
with a normal stopper, and a reference spectrum was taken. The
tube was heated in the dark at 140 °C for 2 h. After cooling to
room temperature, a spectrum was taken showing complete
isomerization of the macrocycle and removal of pyridine, giving a
Supporting Information Available: X-ray crystallographic data
for 10th2+; synthesis and characterization of 4 and 5 (S1,S2); 13C
NMR data of the ruthenium complexes (S2,S6); electronic spectra
2+
2+
of 10th and 10photo (S6); thermo- and photoprocesses for a
+
stripped down version of 8th (S7,S10). This material is available
free of charge via the Internet at http://pubs.acs.org.
IC700734Q
Inorganic Chemistry, Vol. 46, No. 25, 2007 10533