Cyclometalated complexes of Ru(II) with 2-aryl derivatives of quinoline and 1,10-phenanthroline

Article abstract of DOI:10.1021/ic0102844

Difficulty in cyclometalating 1-(2′-quinolinyl)pyrene and 1,3-di-(2′-quinolinyl)pyrene with Ru(II) led to a more detailed study of the cyclometalation process. A series of 2-aryl-1,10-phenanthrolines, where aryl = phenyl, 2-naphthyl, 1-anthracenyl, and 1-pyrenyl, were treated with [Ru(tpy)Cl₃] to provide either the N5Cl complex [Ru(tpy)(L)Cl]⁺ or this same material as a mixture with the N5C cyclometalated species [Ru(tpy)L]⁺. Steric effects appear to govern the ability of the ligand to attain the near planar conformation required for cyclometalation. The bridged ligand 3,1′-dimethylene-2-(2′-pyrenyl)-1,10-phenanthroline was prepared along with a quinoline analogue. The former species was found to cyclometalate at the Cl of pyrene and afford the N5Cl complex. Both the N5C (P2₁/n (monoclinic), a = 28.1102(11), b = 8.4638(3), c = 31.2908(12) A, Z = 8) and N5Cl (P-1 (triclinic), a = 11.7235 (10), b = 14.5306(12), c = 14.5725(12) A, Z = 2) complexes were analyzed by X-ray crystallography, and the N5Cl species evidenced a congested environment for pyrene, which is apparently stabilized by πstacking with tpy. Similar reactions with a series of three 3,2′-bridged derivatives of 2-phenyl-1,10-phenanthroline provide both N5Cl and cyclometalated products in proportions which support the importance of πstacking. The electronic absorption spectra and redox potentials for these complexes evidence strong σdonation by the cyclometalated ligand and an apparant insensitivity to the orthogonal 2-aryl group.

Full text of DOI:10.1021/ic0102844

Inorg. Chem. 2001, 40, 5851-5859
5851
Cyclometalated Complexes of Ru(II) with 2-Aryl Derivatives of Quinoline and
1,10-Phenanthroline
Ce´line Bonnefous, Abdellatif Chouai, and Randolph P. Thummel*
Department of Chemistry, University of Houston, Houston, Texas 77204-5003
ReceiVed March 14, 2001
Difficulty in cyclometalating 1-(2′-quinolinyl)pyrene and 1,3-di-(2′-quinolinyl)pyrene with Ru(II) led to a more
detailed study of the cyclometalation process. A series of 2-aryl-1,10-phenanthrolines, where aryl ) phenyl,
2-naphthyl, 1-anthracenyl, and 1-pyrenyl, were treated with [Ru(tpy)Cl3] to provide either the N5Cl complex
[Ru(tpy)(L)Cl]+ or this same material as a mixture with the N5C cyclometalated species [Ru(tpy)L]+. Steric
effects appear to govern the ability of the ligand to attain the near planar conformation required for cyclometalation.
The bridged ligand 3,1′-dimethylene-2-(2′-pyrenyl)-1,10-phenanthroline was prepared along with a quinoline
analogue. The former species was found to cyclometalate at the C1 of pyrene and afford the N5Cl complex. Both
the N5C (P21/n (monoclinic), a ) 28.1102(11), b ) 8.4638(3), c ) 31.2908(12) Å, Z ) 8) and N5Cl (P-1
(triclinic), a ) 11.7235 (10), b ) 14.5306(12), c ) 14.5725(12) Å, Z ) 2) complexes were analyzed by X-ray
crystallography, and the N5Cl species evidenced a congested environment for pyrene, which is apparently stabilized
by π stacking with tpy. Similar reactions with a series of three 3,2′-bridged derivatives of 2-phenyl-1,10-
phenanthroline provide both N5Cl and cyclometalated products in proportions which support the importance of
π stacking. The electronic absorption spectra and redox potentials for these complexes evidence strong σ donation
by the cyclometalated ligand and an apparant insensitivity to the orthogonal 2-aryl group.
Introduction
case, a relatively long-lived excited state was observed. We
thought it might be of interest to incorporate, by cyclometalation
The exact manner in which certain chelating ligands, such
as 2,2′-bipyridine (bpy) or 2,2′;6′,2′′-terpyridine (tpy), coordinate
with d6 transition metals is not always well understood. In a
recent study, we examined the coordination of a series of tpy
analogues with [RuCl3‚3H2O] and found that, along with
formation of the expected hexaaza-coordinated (N6) species,
varying amounts of a pentaaza-coordinated (N5Cl) complex
were formed.1 Various structural features govern which of these
two types of complex is preferred. We also observed that, in
some cases, the N5Cl species could convert to the N6, and a
mechanism was suggested which involved backside displace-
ment of chloride from the metal by the dangling uncomplexed
portion of one tpy-type ligand.
If one of the pyridine rings of bpy or tpy is replaced by
benzene or another aromatic hydrocarbon, then bidentate or tri-
dentate chelation can only take place, with concurrent cyclo-
metalation of an aryl C-H bond.2 Sauvage and co-workers have
examined 1,3-di-(2′-pyridyl)-benzene3 and 2,9-di-p-tolyl-1,10-
phenanthroline,4 both of which undergo tridentate chelation
with Ru(II) by cyclometalating at a benzene ring. In the latter
to Ru(II), an arene which had more accessible π* states, and
pyrene seemed like an excellent candidate. This paper will
discuss our efforts to cyclometalate pyrene and related studies
aimed at a better understanding of the cyclometalation process.5
Complexation Studies. An initial objective was to prepare
a cyclometalated derivative of Ru(II) in which the carbanionic
moiety would be part of a pyrene ring. We reasoned that an
electro- and photoactive nucleus, such as pyrene, with low lying
π* states would interact in an interesting way if covalently
bound to ruthenium. To test this theory we prepared 1-(2′-
quinolinyl)pyrene (3H) by the Friedla¨nder condensation of
2-aminobenzaldehyde (2) with 1-acetylpyrene (1).6 Treatment
of this ligand with [Ru(bpy)2Cl2] in refluxing aqueous ethanol
led only to recovery of the starting materials.
* To whom correspondence should be addressed.
(1) Jahng, Y.; Thummel, R. P.; Bott, S. G. Inorg. Chem. 1997, 36, 3133.
(2) (a) Constable, E. C.; Rees, D. G. F. New J. Chem. 1997, 21, 369. (b)
Constable, E. C.; Dunne, S. J.; Rees, D. G. F.; Schmitt, C. X. J. Chem.
Soc., Chem. Commun. 1996, 1169. (c) Constable, E. C.; Thompson,
A. M. W. C. New J. Chem. 1996, 20, 65. (d) Constable, E. C.;
Thompson, A. M. W. C.; Cherryman, J.; Liddiment, T. Inorg. Chim.
Acta 1995, 235, 165. (e) Constable, E. C.; Thompson, A. M. W. C.;
Greulich, S. J. Chem. Soc., Chem. Commun. 1993, 1444. (f) Constable,
E. C.; Hannon, M. J. Inorg. Chim. Acta 1993, 211, 101. (g) Constable,
E. C.; Henney, R. P. G.; Tocher, D. A. J. Chem. Soc., Dalton Trans.
1992, 2467. (h) Constable, E. C.; Henney, R. P. G.; Tocher, D. A. J.
Chem. Soc., Dalton Trans. 1991, 2335. (i) Constable, E. C.; Henney,
R. P. G.; Leese, T. A.; Tocher, D. A. J. Chem. Soc., Dalton Trans.
1990, 443. (j) Constable, E. C.; Holmes, J. M. J. Organomet. Chem.
1986, 301, 203. (k) Constable, E. C. Polyhedron 1984, 3, 1037.
We reasoned that in the planar conformation of 3H required
for cyclometalation at C2, there would be an unfavorable
(3) Barigelletti, F.; Flamigni, L.; Massimo, G.; Juris, A.; Beley, M.;
Chodorowski-Kimines, S.; Collin, J.-P.; Sauvage, J.-P. Inorg. Chem.
1996, 35, 136. (b) Beley, M.; Chodorowski, S.; Collin, J.-P.; Sauvage,
J.-P.; Flamigni, L.; Barigelletti, F. Inorg. Chem. 1994, 33, 2544. (c)
Beley, M.; Collin, J.-P.; Sauvage, J.-P. Inorg. Chem. 1993, 32, 4539.
(d) Beley, M.; Chodorowski, S.; Collin, J.-P.; Sauvage, J.-P. Tetra-
hedron Lett. 1993, 34, 2933. (e) Beley, M.; Collin, J.-P.; Louis, R.;
Metz, B.; Sauvage, J.-P. J. Am. Chem. Soc. 1991, 113, 8521.
10.1021/ic0102844 CCC: $20.00 © 2001 American Chemical Society
Published on Web 10/06/2001

5852 Inorganic Chemistry, Vol. 40, No. 23, 2001
Bonnefous et al.
interaction between H10 on pyrene and H3′ on quinoline. To
assess the importance of this effect, 2-phenylquinoline (4H) was
examined and also found to be unreactive when refluxed in
aqueous ethanol with [Ru(bpy)2Cl2]. Conformational mobility
about the (2-1′)-bond in 4H could also be a problem, so we
examined the dimethylene bridged analogue 5H, where a two
carbon bridge holds the molecule approximately planar.7 Again,
cyclometalation was not observed. Both reactions were also
unsuccessful using Ag(I) to activate the reagent in a manner
similar to that employed by Constable and Holmes for the
cyclometalation of 2-phenylpyridine.2j Considering that the
initial step in the desired process would be N-Ru complexation,
the interference of both the C2 phenyl group and quinoline H8
apparently prevent this crucial first step.
bond, which helps to stabilize the system, would most likely
form only after the cyclometalation step had occurred. It is
interesting that 9H will undergo the prerequisite initial N-Ru
coordination even though the ligand is more sterically encum-
bered than 4H, which does not cyclometalate. The difference
may be explained by comparing attack on [Ru(bpy)2Cl2] with
[Ru(tpy)Cl3], where the latter species is more sterically acces-
sible. It is noteworthy that the oxidation state of ruthenium
differs for these two reagents. One could argue that Ru(III) is
more electrophilic and, hence, more reactive in the first com-
plexation step. Reduction of the metal (accompanied by solvent
oxidation) occurs during the stepwise coordination, probably
after complexation of the first pyridine.
To help overcome this reluctance to cyclometalate, we next
investigated systems which were more analogous to those
studied by Sauvage. If the pyrene were part of a potential
tridentate chelator, the chance for inducing cyclometalation
might improve. The condensation of 2 equiv of 2-aminoben-
zaldehyde with 1,3-diacetylpyrene (6)8 provided 1,3-di-(2′-
quinolinyl)pyrene (7H) in 72% yield. Attempted complexation
with [Ru(tpy)Cl3] was unsuccessful, and unreacted starting
materials were recovered. The same result was obtained when
the complexation protocol of Sauvage was followed, wherein
the [Ru(tpy)Cl3] was first activated by solvolysis with AgClO4
in acetone.3e
To probe the cyclometalating ability of increasingly delocal-
ized aromatic systems, we next examined the series of ligands
10a-dH, which had been prepared in earlier work.10 These
ligands are all 2-aryl derivatives of 1,10-phenanthroline (phen)
where cyclometalation at an ortho position of the 2-aryl ring is
expected to lead to an NNC complex. It was anticipated that
initial bidentate coordination to the phen portion of the ligand
would facilitate the cyclometalation step.
The reagent [Ru(tpy)Cl3] consists of a tpy, one chloride bound
in the equatorial plane, and two axial chlorides. When 2-phen-
ylphen (10aH) was treated with [Ru(tpy)Cl3] a mixture of two
products was formed. The formation of these products might
depend on whether initial attack of the more sterically accessible
phen N10 occurred to replace an axial or equatorial chloride.
In the case of axial attack, the NNC cyclometalated complex
[Ru(tpy)(10a)]+ was formed in 35% yield. If initial attack occurs
to replace an equatorial chloride, the N5Cl complex [Ru(tpy)-
(10aH)Cl]+ is formed in 12% yield. The two complexes are
readily characterized by several diagnostic 1H NMR reso-
nances.2f,11 For [Ru(tpy)(10a)]+, H3′, which is adjacent to the
cyclometalated C2′ carbon, is highly shielded and, therefore,
shifted upfield, appearing as a doublet at 5.79 ppm. For the
N5Cl complex [Ru(tpy)(10aH)Cl]+, the ortho protons on the
phenyl ring (H2′ and H6′) are shielded and appear as a doublet
at 6.11 ppm. This shielding is due both to the tpy ring, which
lies parallel to the phenyl ring, and the phen ring, which is
orthogonal, causing H2′ and H6′ to lie partially above and below
When 1,3-diacetylbenzene was substituted for 6, the ligand
1,3-di-(2′-quinolinyl)benzene (9H) could be prepared in 56%
yield, and this species did form a cyclometalated complex with
[Ru(tpy)Cl3]. This result was somewhat surprising in that the
kinetic acidity of pyrene is considerably greater than that of
benzene.9 These observations led us to more carefully consider
the discrete steps involved in the formation of complexes such
as [Ru(tpy)(9)]+. After the initial coordination of a quinoline
nitrogen of either 3H or 7H with ruthenium, the pyrene must
then oxidatively add to the metal center. The third coordinative
(4) Collin, J.-P.; Kayhanian, R.; Sauvage, J.-P.; Calogero, G.; Barigelletti,
F.; De Cian, A.; Fischer, J. J. Chem. Soc., Chem. Commun. 1997,
775.
(5) Bruce, M. I. Angew. Chem., Int. Ed. Engl. 1977, 16, 73.
(6) (a) Thummel, R. P. Synlett. 1992, 1. (b) Cheng, C.-C.; Yan, S.-J. Org.
React. 1982, 28, 37.
(7) Thummel, R. P.; Decloitre, Y.; Lefoulon, F. J. Heterocycl. Chem. 1986,
23, 689.
(8) (a) Scott, L. T.; Necula, A. J. Org. Chem. 1996, 61, 386. (b) Harvey,
R. G.; Pataki, J.; Lee, H. Org. Prep. Proced. Int. 1984, 16, 144.
(9) Cram, D. J. Fundamentals of Carbanion Chemistry; Academic Press:
New York, 1965; p 26.
(10) Riesgo, E. C.; Jin, X.; Thummel, R. P. J. Org. Chem. 1996, 61, 3017.
(11) Reveco, P.; Medley, J. H.; Garber, A. R.; Bhacca, N. S.; Selbin, J.
Inorg. Chem. 1985, 24, 1096.

Cyclometalated Complexes of Ru(II)
Inorganic Chemistry, Vol. 40, No. 23, 2001 5853
its shielding face. Even more characteristic is H9 which is
strongly deshielded by the proximal chloride and appears as a
doublet at 10.46 ppm. Due to the presence of a number of
independent spin systems, it was often possible to make
1
complete proton assignments by careful analysis of the 2D H
NMR.
For 10cH and 10dH, the course of the reaction appears to
be dictated by the conformation of the pendant 2-aryl group. In
both cases the planar conformation required for cyclometalation
to give a five-membered chelate ring would involve an
unfavorable interaction between H3 on phen and a proton on
the aryl substituent. This interaction is avoided when the aryl
group lies orthogonal to the plane of the phen ring, and in this
conformation, a favorable π stacking effect is also evident
between the aryl group and the incoming tpy.
To hold a 2-pyrenyl group more coplanar to the phen and
avoid the unfavorable H,H interaction, we next chose to examine
ligand 13H, which could be prepared in 90% yield by the
condensation of 9,10-dihydrobenzo[a]pyren-7(8H)-one (11) with
8-amino-7-quinolinecarbaldehyde (12).10 In this instance, the
cyclometalated N5C complex [(tpy)Ru(13)]+ was obtained in
46% yield along with 29% of the N5Cl complex [(tpy)Ru(13H)-
Cl]+. It is noteworthy that the C1 of pyrene is considerably
more reactive toward electrophiles than C2. This reactivity
difference may also play an important role in the results obtained
for 13H versus 10dH.
When the 2-(2′-naphthyl) derivative 10bH is treated with [Ru-
(tpy)Cl3], three products are formed, but now the noncyclo-
metalated product predominates and is afforded in 35% yield.
It is again identified by the H9 resonance at 10.47 ppm. In the
upfield region we observe the protons ortho to the C2-phen
bond, a doublet for H3′ at 6.26 ppm, and a singlet for H1′ at
6.52 ppm. A mixture of two cyclometalated products were
formed in a 4/1 ratio, and this mixture could not be separated.
The major product was bound to ruthenium at C2′, giving rise
to a singlet at 6.15 ppm for H4′. The minor product was bound
to ruthenium at C1′, giving rise to a doublet at 6.42 ppm for
H8′.
The successful tridentate cyclometalation of 13H raised the
question of whether a similar bidentate reaction might be
possible utilizing C1 and a bridged analogue of 3H. Thus, ligand
14H was prepared in 84% yield by the reaction of 11 with 2.
Treating 14H with [Ru(bpy)2Cl2] under normal conditions
(refluxing aqueous ethanol), using AgBF4, or even in a
microwave reactor (glycerol), led only to recovered ligand.
With the 1-anthracenyl derivative 10cH, a 47% yield of only
the N5Cl product [Ru(tpy)(10cH)Cl]+ is obtained. It is char-
acterized by the highly deshielded H9 resonance at 10.44 ppm
and a shielded doublet for H2′ at 5.92 ppm.
In an earlier study, we observed that exposure of the N5Cl
product, [Ru(tpy)2Cl]+, to ambient light resulted in a smooth
conversion to the fully coordinated N6 species by what appeared
to be a backside displacement of chloride by the uncomplexed
nitrogen.1 A similar experiment using [Ru(tpy)(10aH)Cl]+ did
A similar result is obtained for the 1-pyrenyl drivative 10dH,
which provides a 32% yield of the N5Cl product [Ru(tpy)-
(10dH)Cl]+ characterized by the highly deshielded H9 resonance
at 10.43 ppm and a shielded doublet for H2′ at 6.53 ppm.

5854 Inorganic Chemistry, Vol. 40, No. 23, 2001
Bonnefous et al.
not evidence any change due to the weak nucleophilicity of
benzene as compared to pyridine.
An important factor in determining the precoordination
geometry leading to N5Cl complexation is the degree of
flexibility about the bond joining the aryl substituent to the phen
ring. The more orthogonal these two rings are to one another,
the more easily the phen ring is able to coordinate. Furthermore,
an orthogonal 2-aryl ring may π stack with the incoming tpy,
thus providing a favorable precoordination geometry. To probe
this effect, a series of bridged derivatives of 2-phenylphen
(10aH) was prepared.
The Friedla¨nder condensation of 8-amino-7-quinolinecarbal-
dehyde (12) with 1-tetralone (15a) or benzosuberone (15b) led
to the dimethylene and trimethylene bridged derivatives 16a,bH
in yields of 82% and 52%, respectively. The dimethylene species
16aH could be dehydrogenated in 59% yield by heating with
palladium on carbon in nitrobenzene for 2 days. Molecular
mechanics calculations were used to determine the approximate
geometry of an energy minimized form of these three ligands;
particular attention was paid to the dihedral angle about the 2,2′-
bond.12 For 16aH, this angle was estimated to be 17°, for 16bH
it was estimated at 44°, and 17H was found to be approximately
planar. These three ligands were then complexed with [Ru(tpy)-
Cl3] with quite different results.
Figure 1. ORTEP drawing of the cation of [Ru(tpy)(13)](PF6) with
atomic numbering scheme.
Table 1. Selected Bond Lengths, Bond Angles, and Dihedral
Angles for [Ru(13)(tpy)](PF6) and [Ru(13H)(tpy-d11)Cl](PF6)a
[Ru(13)(tpy)](PF6)
[Ru(13H)(tpy-d11)Cl](PF6)
Bond Lengths (Å)
Ru-N1
2.188(3)
Ru-N1
2.074(5)
2.135(4)
2.3767(14)
2.080(4)
1.954(4)
2.057(4)
Ru-N24
Ru-C21
Ru-N33
Ru-N39
Ru-N45
2.007(3)
2.091(3)
2.063(3)
1.959(3)
2.064(3)
Ru-N24
Ru-Cl
Ru-N33
Ru-N39
Ru-N45
Bond Angles (°)
N1-Ru-N24
N24-Ru-C21
N33-Ru-N39
N39-Ru-N45
N24-Ru-N39
76.68(10)
78.68(11)
78.94(10)
79.24(11)
176.03(11)
N1-Ru-N24
N24-Ru-Cl
N33-Ru-N39
N39-Ru-N45
79.33(17)
166.16(11)
78.89(17)
79.75(17)
Dihedral Angles (°)
N33-C38-C40-N39 -0.8(4) N33-C38-C40-N39 -5.3(7)
C37-C38-C40-C41 0.7(6) C37-C38-C40-C41 -8.3(9)
N39-C44-C46-N45 -5.0(4) N39-C44-C46-N45 -0.2(7)
1.4(9)
C43-C44-C46-C47 -9.1(6) C43-C44-C46-C47
C21-C22-C23-N24 -10.1(4) C21-C22-C23-N24 -34.3(7)
C13-C22-C23-C10 -15.5(5) C13-C22-C23-C10 -31.8(6)
For 16bH, which showed the greatest degree of twist about
the 2,2′-bond, π stacking of the 2-phenyl substituent with the
tpy of the reagent would dispose the phen moiety in a manner
reasonably favorable to initial complexation of N1 in the
equatorial plane of [Ru(tpy)Cl3], and thus, 34% [Ru(tpy)(16bH)-
Cl]+ was obtained, as compared to only 6% of the cyclometa-
lated complex [Ru(tpy)(16b)]+. For 16aH, the ligand is more
planar and thus less able to adopt a conformation favorable to
precoordination π stacking. Nevertheless, formation of the N5Cl
species [Ru(tpy)(16aH)Cl]+ still accounts for 48% of the
product, while 40% of cyclometalated [Ru(tpy)(16a)]+ is also
obtained. For 17H, the ligand is essentially planar, and only
the cyclometalated species [Ru(tpy)(17)]+ is observed in 57%
yield.
Properties of the Complexes. The distinctly different com-
plexation results obtained for 10dH and 13H prompted us to
more closely examine the structural properties of the two
complexes derived from the latter species. Figure 1 illustrates
the ORTEP drawing of the cation associated with the cyclo-
metalated species [Ru(tpy)(13)](PF6), and Table 1 summarizes
some of the important geometric features of this complex. The
two ligands are oriented in approximately orthogonal planes as
one would expect for normal bis-tridentate octahedral coordina-
tion. The Ru-C21 bond to pyrene is slightly shorter than the
opposing Ru-N1 bond, reflecting the stronger σ donor ability
a Numbering pattern from Figures 1 and 2 with esd’s in paren-
theses.
of the anionic carbon. This causes the N1-Ru-N24 angle to
be about 2° less than the N24-Ru-C21 angle, pushing C19
toward the central pyridine of the tpy ligand. The attached proton
(H4′) is therefore strongly shielded and appears as the highest
field aromatic resonance in the 1H NMR (doublet at 6.46 ppm).
The degree of twist between the phen and pyrene rings can be
estimated as 12.8°, the average of the two dihedral angles
containing C22 and C23. This twist relieves eclipsing interac-
tions in the dimethylene bridge while allowing efficient triden-
tate complexation.
A suitable crystal of the N5Cl complex was obtained from
an experiment in which tpy-d11 was substituted for tpy. The
situation for this complex is more interesting in that two binding
modes are possible for the phen ligand, with N1 either occupying
a site in the equatorial plane of the tpy ligand or the axial site
orthogonal to this plane. Steric considerations appeared to favor
N1 being axial so as to position tpy away from the bulky pyrene
residue. The 1H NMR spectrum for the complex showed a highly
deshielded doublet for H9 (attached to C2 in Figure 2) appearing
at 10.28 ppm. The small coupling constant of 5.3 Hz is
diagnostic of H9, and the deshielding is due to the proximal
chlorine. The X-ray structure supports the NMR assignment,
showing the tpy to be close to the pyrene moiety. A similar
(12) Calculations were performed with the program PC MODEL available
from Serena Software, Bloomington, IN.

Cyclometalated Complexes of Ru(II)
Inorganic Chemistry, Vol. 40, No. 23, 2001 5855
Table 2. Electronic Absorption Maxima (nm) and Molar
Absorptivities (log ꢀ) for the Ligands and Their Ru(II) Complexesa
compound
10aH
[Ru(tpy)(10a)]+
λmax (log ꢀ)
351 (3.69), 285 (4.76), 234 (4.89)
512 (4.17), 316 (4.65), 303 (4.66),
277 (4.75), 233 (4.84)
[Ru(tpy)(10aH)Cl]+ 500 (4.05), 320 (4.45), 269 (4.71), 227 (4.73)
10bH
276 (4.55), 237 (4.73), 215 (4.56)
515 (4.16), 305 (4.68), 275 (4.65),
233 (4.78), 199 (4.82)
[Ru(tpy)(10b)]+
[Ru(tpy)(10bH)Cl]+ 501 (4.03), 317 (4.46), 269 (4.78), 222 (4.94),
10cH
380 (3.95), 252 (5.02), 230 (4.81)
[Ru(tpy)(10cH)Cl]+ 503 (4.01), 321 (4.38), 270 (4.83),
251 (4.88), 238 (4.88), 201 (4.77)
10dH
342 (4.44), 277 (4.67), 233 (4.94), 195 (4.80)
Figure 2. ORTEP drawing of the cation of [Ru(tpy)(13H)(Cl)](PF6)
[Ru(tpy)(10dH)Cl]+ 502 (4.02), 321 (4.63), 270 (4.89), 238 (4.95)
with atomic numbering scheme.
13H
394 (4.11), 358 (4.39), 343 (4.62),
306 (4.69), 242 (4.59)
514 (4.19), 464 (4.04), 395 (4.39),
319 (4.75), 235 (4.71)
511 (3.81), 315 (4.53), 277 (4.47), 238 (4.59)
356 (4.06), 339 (4.06), 293 (4.48),
238 (4.68), 192 (4.37)
511 (4.19), 303 (4.58), 277 (4.58),
236 (4.72), 195 (4.76)
orientation was observed in an N5Cl complex reported earlier.1
Compared with the cyclometalated complex, the Ru-N1 bond
shortens and the Ru-N24 bond lengthens, reflecting some steric
congestion between the two organic ligands. The dihedral angle
between the phen and pyrene rings has increased to about 33°,
and there appears to be a π-π interaction between the benzo
ring bonded to phen and the central pyridine of tpy. The distance
between the centers of these two rings is 3.63 Å, and the dihedral
angle between their mean planes is 30.8°.
The seven N5Cl complexes which have been characterized
in this study show resonances for H9 in the range of 10.20-
10.46 ppm, indicating that they all have a geometry similar to
[Ru(tpy)(13H)Cl](PF6). This consistency allows us to analyze
the complexation process leading to this geometry. Ligands
10cH and 10dH have larger π surfaces and the freedom to orient
the 2-aryl ring orthogonal to the phen. The π stacking of this
2-aryl ring with the tpy of the incoming Ru(II) reagent would
favor the observed geometry. Systems where this π surface is
smaller (10aH) or where a dimethylene bridge may enforce
planarity of the ligand thereby inhibiting effective π stacking
(13H or 16aH) may lead to increased amounts of cyclometalated
products.
The electronic absorption data for the ligands and their
Ru(II) complexes are summarized in Table 2. An interesting
trend can be noted for the three bridged ligands. As the bridge
lengthens in going from 16aH to 16bH, the degree of conjuga-
tion between the 2-phenyl substituent and the phen is dimin-
ished, resulting in a shift of the absorption maximum to higher
energy.7 For 17H, the absorption maximum appears at consider-
ably longer wavelength (387 nm) due to the more delocalized
π system of this fully conjugated molecule.
The two classes of Ru(II) complexes show distinct properties
in their electronic absorption spectra. The seven N5Cl complexes
show a long wavelength maximum in the range of 500-511
nm. This absorption is attributed to the typical metal-to-ligand
charge transfer (MLCT) that is characteristic of most Ru(II)
polypyridine complexes.13 The MLCT band for [Ru(tpy)2]2+ in
acetonitrile appears at 474 nm. An approximate 30 nm shift to
lower energy for the N5Cl complexes may be explained by
destabilization of the metal t2g orbital, which is caused by the
chloride being a stronger π donor than the pyridine ligand. It is
quite interesting that the increasing conjugation and electron
delocalizing ability of the 2-aryl substituent along the series
10a-dH makes essentially no difference in the absorption
[Ru(tpy)(13)]+
[Ru(tpy)(13H)Cl]+
16aH
[Ru(tpy)(16a)]+
[Ru(tpy)(16aH)Cl]+ 506 (3.96), 317 (4.50), 281 (4.51), 233 (4.69)
16bH
345 (3.51), 329 (3.68), 280 (4.57), 237 (4.73)
517 (4.18), 305 (4.56), 277 (4.58),
237 (4.69), 194 (4.68)
[Ru(tpy)(16b)]+
[Ru(tpy)(16bH)Cl]+ 500 (3.99), 321 (4.43), 276 (4.63), 232 (4.70)
17H
387 (3.71), 366 (3.72), 294 (4.71),
240 (4.39), 222 (4.58)
553 (4.20), 369 (4.22), 316 (4.68),
276 (4.66), 236 (4.75)
[Ru(tpy)(17)]+
a Measured in CH3CN (10-5 M).
spectra, and all four systems show nearly the same MLCT
transition. The implication is that the 2-substituent, being
orthogonal to the phen, is electronically decoupled from the
system and plays essentially no role. It is attractive to suggest
that interligand communication might occur through π stacking
with the tpy, but the electronic spectra offer no support of this
premise. We have observed a similar decoupling of states for
the complex [Ru(bpy)2(10dH)]2+ 14
. The N5Cl complexes also
show a weak, low energy absorption at about 640 nm (Figure
3). We found this identical absorption in the parent system [Ru-
(phen)(tpy)Cl]+, and it appears to be characteristic of N5Cl
chlororuthenium(II) complexes.
For the cyclometalated series, the σ donating effect is more
pronounced, and the absorption maximum of the MLCT band
shifts to 511-517 nm and is somewhat more intense. For these
N5C coordinated systems, the carbanionic ligand is even a
stronger donor than pyridine, leading to greater destabilization
of the ruthenium(II).15 The complex [Ru(tpy)(17)]+ exhibits the
lowest energy transition with a maximum at 553 nm (Figure 3)
due to the extensive delocalization provided by the fully
conjugated 17 and the consequent lowering of the π* state for
this system.
Figure 3 also illustrates the situation for the N5Cl and
cyclometalated complexes of 16a,bH and 17H. Despite their
relatively different conformations, the spectra for both types of
16a,bH complex are remarkably similar, indicating again the
relative unimportance of the 2-aryl substituent. When excited
(14) Simon, J. A.; Curry, S. L.; Schmehl, R. H.; Schatz, T. R.; Piotrowiak,
P.; Jin, X.; Thummel, R. P. J. Am. Chem. Soc. 1997, 119, 11012.
(15) (a) Reveco, P.; Cherry, W. R.; Medley, J.; Garber, A.; Gale, R. J.;
Selbin, J. Inorg. Chem. 1986, 25, 1842. (b) Reveco, P.; Schmehl, R.
H.; Cherry, W. R.; Fronczek, F. R.; Selbin, J. Inorg. Chem. 1985, 24,
4078.
(13) (a) Kalyanasundaram, K. Photochemistry of Polypyridine and Por-
phyrin Complexes; Academic Press: San Diego, 1992. (b) Juris, A.;
Balzani, V.; Barigelletti, F.; Campagna, S.; Belser, P.; von Zelewsky,
A. Coord. Chem. ReV. 1988, 84, 85.

5856 Inorganic Chemistry, Vol. 40, No. 23, 2001
Bonnefous et al.
cyclometalated complexes are again quite consistent. The
complexes of 2-phenylphen and its bridged derivatives all reduce
at essentially the same potential (-1.57, -1.58 V). The more
delocalized naphthalene system [Ru(tpy)(10b)]+ reduced more
readily at -1.49 V, and [Ru(tpy)(17)]+ is the easiest to reduce
at -1.33 V. The N5Cl complexes reduce more easily than their
cyclometalated counterparts by 0.07-0.14 V, which is consistent
with the carbanionic nature of the cyclometalated ligand. It is
a little difficult to understand why the N5Cl complexes of the
anthracenyl and pyrenyl systems are more difficult to reduce
than their phenyl and naphthyl counterparts.
Conclusions
A variety of 2-aryl substituted derivatives of quinoline and
1,10-phenanthroline have been prepared and their possible
complexation with Ru(II) has been examined. Of the six
quinoline derivatives, only the 1,3-di-(2′-quinolinyl)benzene
(9H) was found to undergo cyclometalation with [Ru(tpy)Cl3].
None of the potential bidentate cyclometalators reacted with
[Ru(bpy)2Cl2]. In contrast, all the 2-arylphen derivatives formed
complexes with [Ru(tpy)Cl3]. Cyclometalation was observed
when the incoming ligand was planar or could readily adopt a
planar conformation. The more accessible nature of the cen-
tral metal atom may account for the greater reactivity found
with the tpy reagent, although the increased electrophilicity of
Ru(III) may also play a role. The geometry of the N5Cl com-
plexes, as best evidenced by [Ru(tpy)(13H)Cl]+, favors π
stacking between the 2-aryl group and the tpy ligand over a
less congested orientation which would hold these ligands
further apart. The electrochemical reduction data does not
support participation by low lying π* states. In the N5Cl
complexes this may be due to reduced conjugation with the
coordinated phen and for the cyclometalated systems because
of the anionic nature of the carbon-bound moiety.
Figure 3. Long wavelength region of the electronic absorption spec-
tra of Ru(II) complexes, 10-5 M in CH3CN: [Ru(tpy)(16a)]+‚‚‚‚‚‚‚‚,
[Ru(tpy)(16aH)Cl]+- - - - - - -, [Ru(tpy)(16b)]+‚ - ‚ - ‚ - ‚ -, [Ru(tpy)-
(16bH)Cl]+‚‚ - ‚‚ - ‚‚ - ‚‚ -, and [Ru(tpy)(17)]+ s.
Table 3. Half Wave Oxidation and Reduction Potentials (V versus
SCE) for the Ru(II) Complexesa
complex
E1/2 (ox)
E1/2 (red)
[Ru(tpy)(10a)]+
0.58 (90), 1.27 (100)
-1.58 (90), -1.86 (90)
-1.46 (100)
[Ru(tpy)(10aH)Cl]+ 0.81 (80)
[Ru(tpy)(10b)]+
0.58 (80), 1.36 (100)
-1.49 (90)
[Ru(tpy)(10bH)Cl]+ 0.81 (90)
[Ru(tpy)(10cH)Cl]+ 0.83 (100)
[Ru(tpy)(10dH)Cl]+ 0.84 (100)
-1.37 (90), -1.80 (90)
-1.52 (60), -1.85 (irr)b
-1.59 (100), -1.86 (irr)
[Ru(tpy)(13)]+
0.57 (100), 1.13 (160) -1.51 (90), -1.82 (150)
0.84 (90)
0.60 (80), 1.33 (100)
[Ru(tpy)(13H)Cl]+
[Ru(tpy)(16a)]+
-1.57 (85), -1.86 (irr)
-1.57 (80), -1.89 (110)
-1.43 (70), -1.76 (80)
-1.58 (80), -1.89 (110)
-1.51 (80)
[Ru(tpy)(16aH)Cl]+ 0.83 (90)
[Ru(tpy)(16b)]+
0.54 (80), 1.19 (120)
[Ru(tpy)(16bH)Cl]+ 0.80 (90)
[Ru(tpy)(17)]+
0.62 (90), 1.34 (irr)
-1.33 (90)
Experimental Section
a Solutions were 0.1 M TBAP in CH3CN; the sweep rate was 200
mV/s; the number in parentheses is the difference (mV) between the
anodic and cathodic waves. b Irr ) irreversible.
Nuclear magnetic resonance spectra were recorded on a General
Electric QE-300 spectrometer at 300 MHz for 1H NMR and 75 MHz
for 13C NMR. Chemical shifts are reported in parts per million
downfield from Me4Si. Electronic spectra were obtained on a Perkin-
Elmer 330 spectrophotometer. Cyclic voltammograms were recorded
using a BAS CV-27 voltammograph and a Houston Instruments Model
100 X-Y recorder according to a procedure which has been described
previously.17 Mass spectra were obtained on a Hewlett-Packard 5989B
mass spectrometer (59987A electrospray) using atmospheric pressure
ionization at 160 °C for the complexes and atmospheric pressure
chemical ionization at 300 °C for the ligands. All solvents were freshly
distilled reagent grade, and all melting points are uncorrected. Elemental
analyses were performed by National Chemical Consulting, Inc., P.O.
Box 99, Tenafly, NJ 07670.
at the wavelength of their MLCT absorption, none of the
complexes studied showed appreciable luminescence at room
temperature.
The half wave oxidation and reduction data for the Ru(II)
complexes, as determined by cyclic voltammetry, are sum-
marized in Table 3. Again there is a strong consistency of the
data. Oxidations of the N5Cl complexes all occur in the range
of +0.80 to +0.84 V, which is substantially less than the
potential of +1.27 V16 observed for [Ru(tpy)2]2+. Since oxida-
tion of complexes of this type are known to be metal based,13
it is the better π donor ability of chloride as compared to
pyridine which raises the energy of the ruthenium t2g orbital
and thus diminishes the energy required for oxidation. The σ
donor effect is stronger for the carbanionic cyclometalated
complexes, where now the range of oxidation potentials is still
lower, +0.54 to +0.62 V. Insensitivity to the ligand is illustrated
by [Ru(tpy)(17)]+ which, despite the more delocalized nature
of 17, falls in line with the other systems. For the six
cyclometalated complexes reported in Table 3, a second
oxidation band is observed at 1.13-1.36 V and is tentatively
assigned to the removal of an electron from the carbanionic
ligand.
Literature procedures were followed for the preparation of 2-ami-
nobenzaldehyde,18 8-amino-7-quinolinecarbaldehyde,10 1,3-diacetylpyrene,8
and [Ru(tpy)Cl3].19
1-(2′-Quinolinyl)pyrene (3H). A mixture of 1-acetylpyrene (244
mg, 1.0 mmol), 2-aminobenzaldehyde (121 mg, 1.0 mmol), and KOH
(80 mg) in absolute EtOH (20 mL) was refluxed for 12 h under Ar
and cooled to 25 °C. The mixture was added to H2O (30 mL) and then
extracted with CH2Cl2 (75 mL) to give 3H (170 mg, 50%) as a yellow
solid, mp 143-147 °C: 1H NMR (CDCl3): δ 8.46 (d, 1H, J ) 9.4
Hz), 8.37 (d, 1H, J ) 8.6 Hz), 8.29 (dd, 2H, J ) 7.9-11.0 Hz), 8.26
(d, 1H, J ) 6.4 Hz), 8.18 (dd, 2H, J ) 8.6-9.5 Hz), 8.14 (s, 2H), 8.10
(17) Goulle, V.; Thummel, R. P. Inorg. Chem. 1990, 29, 1767.
(18) Opie, J. W.; Smith, L. I. Organic Syntheses; Wiley and Sons: New
York, 1955; Coll. Vol. III, p 56.
The reductions are ligand based and represent the addition
of an electron to a ligand π* orbital.12 In this regard, the
(19) Sullivan, B. P.; Calvert, J. M.; Meyer, T. J. Inorg. Chem. 1980, 19,
1404.
(16) Thummel, R. P.; Chirayil, S. Inorg. Chim. Acta 1988, 154, 77.

Cyclometalated Complexes of Ru(II)
Inorganic Chemistry, Vol. 40, No. 23, 2001 5857
(d, 1H, J ) 9.4 Hz), 8.03 (t, 1H, J ) 7.7 Hz), 7.94 (d, 1H, J ) 8.0
Hz), 7.88 (d, 1H, J ) 8.0 Hz), 7.81 (t, 1H, J ) 7.8 Hz), 7.64 (t, H, J
) 7.8 Hz). 13C NMR (CDCl3): δ 159.6, 148.1, 136.2 (2C), 135.7, 131.5,
131.3, 130.8, 129.8, 129.6, 128.7, 128.1, 127.9, 127.7, 127.5 (2C),
127.3, 126.8, 126.6, 126.0, 125.3, 125.1, 124.8 (2C), 123.7.
NMR (CDCl3): δ 153.3, 150.2, 146.4, 145.0, 138.8, 136.0, 134.6, 134.4,
132.3, 129.6, 128.5, 128.1, 127.6, 127.3, 127.0, 126.2, 125.9, 122.4,
28.6, 28.1. MS: m/z 281 (100, M - 1).
3,2′-Trimethylene-2-phenyl-1,10-phenanthroline (16bH). Follow-
ing the procedure described for 9H, benzosuberone (179 mg, 1.12
mmol) was condensed with 8-amino-7-quinolinecarbaldehyde (192 mg,
1.12 mmol) in absolute EtOH (20 mL) for 18 h. The dark-orange, oily
residue was chromatographed on Al2O3 (30 g), eluting with EtOAc/
hexane (1:1). The second fraction afforded 16bH (173 mg, 52%) as a
yellow solid, mp 112-114 °C. 1H NMR (CDCl3): δ 9.20 (dd, 1H, H9,
J ) 4.2, 1.5 Hz), 8.24 (dd, 1H, H7, J ) 8.1, 1.8 Hz), 8.10 (dd, 1H, H3′,
J ) 7.5, 1.2 Hz), 8.07 (s, 1H, H4), 7.79 (AB quartet, 2H, H5,6), 7.61
(dd, 1H, H8, J ) 8.1, 4.5 Hz), 7.45 (td, 1H, H4′, J ) 7.5, 1.2 Hz), 7.38
(td, 1H, H5′, J ) 7.5, 1.5 Hz), 7.26 (dd, 1H, H6′, J ) 8.4, 1.2 Hz), 2.76
(t, 2H, CH2), 2.59 (t, 2H, CH2), 2.28 (quintet, 2H, CH2). 13C NMR
(CDCl3): δ 150.5, 146.8, 145.0, 140.6, 139.3, 136.2, 135.5, 135.2,
130.2, 129.3, 129.2, 128.7, 128.2, 128.1, 127.2, 126.4, 126.3, 122.7,
32.4, 31.0, 30.8. MS: m/z 295 (100, M - 1).
1,3-Di-(2′-quinolinyl)pyrene (7H). A mixture of 1,3-diacetylpyrene
(28.6 mg, 0.1 mmol), 2-aminobenzaldehyde (24 mg, 0.2 mmol), and
KOH (100 mg) in absolute EtOH (5 mL) was refluxed for 12 h. The
yellow precipitate was filtered, washed with EtOH (2 × 5 mL), and
1
dried to give 7H (32 mg, 72%), mp > 270 °C. H NMR (CDCl3): δ
8.59 (s, 1H, H2), 8.47 (d, 2H, H4 or 5, J ) 9 Hz), 8.37 (d, 2H, H3′
,
or 4′
J ) 8.4 Hz), 8.31 (d, 2H, H8′, J ) 8.4 Hz), 8.24 (d, 2H, H6, J ) 7.8
Hz), 8.14 (d, 2H, H4 5, J ) 9.3 Hz), 8.06 (t, 1H, H7, J ) 7.5 Hz),
or
7.95 (2d, 4H, H5′ and H4 or 5), 7.81 (td, 2H, H7′, J ) 6.9, 1.2 Hz), 7.63
(td, 2H, H6′, J ) 7.5, 0.6 Hz). 13C NMR (CDCl3): δ 159.2, 136.8,
135.0, 131.1, 130.2, 129.9, 129.4, 129.3, 129.2, 128.9, 127.7, 127.0,
126.9, 126.3, 125.8, 125.7, 124.9, 124.7, 124.1. MS: m/z 456 (100,
M).
1,3-Di-(2′-quinolinyl)benzene (9H). A mixture of 1,3-diacetylben-
zene (50 mg, 0.3 mmol), 2-aminobenzaldehyde (72 mg, 0.6 mmol),
and KOH (200 mg) in absolute EtOH (10 mL) was refluxed for 24 h.
The mixture was cooled to 25 °C, and H2O (20 mL) was added. The
aqueous phase was extracted with CH2Cl2 (3 × 15 mL). The organic
phase was dried (MgSO4) and the solvent evaporated to provide a
residue which was recrystallized from ether/CH2Cl2 (6:1) to give 9H
3,2′-Naphtho-[1,2-b]-1,10-phenanthroline (17H). A mixture of
16aH (185 mg, 0.65 mmol) and 10% Pd/C (100 mg) in nitrobenzene
(5 g) was refluxed for 24 h. The reaction mixture was cooled to 25 °C,
and 10% Pd/C (100 mg) in nitrobenzene (2 g) was added. The re-
flux was continued for another 24 h. After cooling, the Pd/C was
removed by filtration through Celite and washed with CH2Cl2 (20 mL).
The CH2Cl2 was evaporated, and the nitrobenzene solution was
chromatographed on Al2O3 (30 g), eluting first with CH2Cl2/hexane
(1:1), to remove all the nitrobenzene, and then with CHCl3, to provide
a brown solid which was washed with Et2O/hexane (1:1) to give 17H
1
(56 mg, 56%) as yellow needles, mp 139-40 °C. H NMR (CDCl3):
δ 8.97 (s, 1H, H2), 8.31-8.23 (m, 6H), 8.04 (d, 2H, J ) 8.7 Hz), 7.87
(d, 2H, H5′, J ) 8.1 Hz), 7.76 (td, 2H, J ) 8.1, 1.2 Hz), 7.71 (t, 1H,
H5, J ) 7.5 Hz), 7.56 (td, 2H, H6′, J ) 7.8, 0.9 Hz). 13C NMR
(CDCl3): δ 157.3, 148.4, 140.4, 137.0, 129.9, 129.8, 129.6, 128.7,
127.7, 127.4, 126.9, 126.5, 119.3. MS: m/z 332 (100, M).
1
(108 mg, 59%) as a beige solid, mp 200-201 °C. H NMR (CDCl3):
δ 9.95 (d, 1H, H8′, J ) 7.8 Hz), 9.34 (dd, 1H, H9, J ) 2.7, 0.9 Hz),
8.69 (s, 1H, H4), 8.31 (d, 1H, H7, J ) 7.8 Hz), 7.96-7.69 (m, 8H). 13
C
3,1′-Dimethylene-2-(2′-pyrenyl)-1,10-phenanthroline (13H). A
mixture of 11 (300 mg, 1.11 mmol), 8-amino-7-quinolinecarbaldehyde
(191 mg, 1.11 mmol), and KOH (120 mg) in absolute EtOH (25 mL)
was refluxed for 12 h under Ar and cooled to 25 °C. After the mixture
was added to H2O (30 mL), the product was filtered, washed with
ethanol, and recrystallized from chloroform to give 13H (406 mg, 90%)
NMR (CDCl3): δ 149.9, 149.8, 147.5, 146.2, 135.6, 135.3, 134,1, 129.3,
129.0, 127.9, 127.7, 127.5, 127.4, 126.8, 126.7, 126.4, 126.0, 125.3,
123.4. MS: m/z 280 (100, M).
[Ru(tpy)(9)](PF6). A mixture of [Ru(tpy)Cl3] (44 mg, 0.1 mmol),
9H (33 mg, 0.1 mmol), and Et3N (3 drops) in EtOH/H2O (3:1, 12 mL)
was refluxed for 12 h. After cooling and filtering, NH4PF6 (16.3 mg,
0.1 mmol) was added to the filtrate, and the solvent was evaporated to
dryness. The resulting mauve residue was chromatographed on Al2O3
1
as a light brown solid, mp 270 °C. H NMR (CDCl3): δ 9.81 (s, 1H,
H4), 9.32 (d, 1H, H9, J ) 3.9 Hz), 8.37 (t, 1H, H7′, J ) 8.2 Hz), 8.26
(d, 1H, H7, J ) 7.9 Hz), 7.95-8.4 (m, 8H, ArH), 7.78 (AB quartet,
2H, H5,6, J ) 7.9 Hz), 7.66 (dd, 1H, H8, J ) 3.9-7.8 Hz), 3.78 (t, 2H,
CH2), 3.44 (t, 2H, CH2). 13C NMR (CDCl3): δ 222.5, 151.0, 150.4,
136.5, 134.6, 133.6, 133.0, 132.8, 132.1, 131.4, 130.2, 129.2, 129.0,
128.7, 128.2, 127.7, 127.1, 126.5, 126.4, 126.3, 125.3, 124.9, 124.0,
123.4, 122.8, 29.1, 24.4. Anal. Calcd for C30H18N2‚0.6 H2O: C, 86.37;
H, 4.61; N, 6.72. Found: C, 86.01; H, 4.62; N, 7.04.
(30 g), eluting with CH3CN/toluene (1:1), to provide the complex as
1
purple crystals (25 mg, 31%), mp > 270 °C. H NMR (CD3CN):20
δ
8.93 (d, 2H, He, J ) 8.1 Hz), 8.57 (d, 2H, H4, J ) 7.5 Hz), 8.53 (t, 1H,
Hf, J ) 8.1 Hz), 8.41 (d, 2H, H4′, J ) 8.7 Hz), 8.33 (d, 2H, Hd, J ) 8.1
Hz), 8.11 (d, 2H, H3′, J ) 8.7 Hz), 7.65 (m, 3H, H5,5′), 7.53 (dd, 2H,
Hc, J ) 7.8, 1.2 Hz), 7.42 (t, 2H, H6′, J ) 7.5 Hz), 7.16 (d, 2H, Ha, J
) 5.4 Hz), 7.00 (td, 2H, H7′, J ) 8.5, 1.5 Hz), 6.84 (td, 2H, Hb, J )
6.6, 0.9 Hz), 6.53 (d, 2H, H8′, J ) 8.7 Hz). MS: m/z 664 (100, M -
PF6).
3,1′-Dimethylene-2-(2′-pyrenyl)-quinoline (14H). Following the
procedure described for 3H, 9,10-dihydrobenzo[a]pyren-7(8H)-one (350
mg, 1.29 mmol) was condensed with 2-aminobenzaldehyde (157 mg,
1.29 mmol) in absolute EtOH (25 mL) for 6 h under Ar. The light
yellow residue was filtered, washed with ethanol, and dried to afford
[Ru(tpy)(10a)](PF6) and [Ru(tpy)(10aH)Cl](PF6). Following the
procedure described for [Ru(tpy)(9)](PF6), 10aH (64 mg, 0.25 mmol)
was treated with [Ru(tpy)Cl3] (110 mg, 0.25 mmol) and refluxed for 5
h. The first fraction gave 72 mg (39%) of [Ru(tpy)(10a)](PF6) as a
purple solid, mp > 270 °C. 1H NMR (CDCl3):20 δ 8.60 (dd, 2H, He, J
) 8.1, 3.0 Hz), 8.53 (AB quartet, 2H, H5,6), 8.40 (d, 2H, Ha, J ) 8.1
Hz), 8.31 (d, 1H, H7, J ) 8.1 Hz), 8.23 (d, 1H, H4, J ) 9.0 Hz), 8.08
(t, 1H, Hf, J ) 8.1 Hz), 8.04 (d, 1H, H3, J ) 9.3 Hz), 7.95 (d, 1H, H6′,
J ) 7.5 Hz), 7.84 (d, 1H, H9, J ) 5.4 Hz), 7.73 (t, 2H, Hb, J ) 7.5
Hz), 7.31 (dd, 1H, H8, J ) 8.4, 5.1 Hz), 7.24 (d, 2H, Hd, J ) 4.8 Hz),
6.90 (td, 2H, Hc, J ) 6.6, 1.5 Hz), 6.76 (td, 1H, H5′, J ) 7.2, 2.7 Hz),
6.54 (td, 1H, H4′, J ) 7.2, 1.2 Hz), 5.80 (d, 1H, H3′, J ) 7.2 Hz). The
second fraction afforded [Ru(tpy)(10aH)Cl](PF6) as a red solid
(22.5 mg, 12%). 1H NMR (CDCl3): δ 10.46 (dd, 1H, H9, J ) 6.3, 0.9
1
14H (384 mg, 84%), mp 220-223 °C. H NMR (CDCl3): δ 9.47 (s,
1H, H4), 8.40 (d, 1H, H8, J ) 8.8 Hz), 7.96-8.30 (m, 8H, ArH), 7.81
(d, 1H, H5, J ) 6.47 Hz), 7.71 (t, 1H, H6, J ) 7.35 Hz), 7.55 (m, 1H,
H7, J ) 7.38 Hz), 3.74 (t, 2H, CH2), 3.37 (t, 2H, CH2). 13C NMR
(CDCl3): δ 154.3, 148.2, 133.9, 133.8 (2C), 132.1, 131.4, 130.8, 130.5,
129.7 (2C), 129.1, 128.7, 128.4, 128.2, 127.8, 127.2, 126.4, 125.9,
125.3, 125.1, 125.0, 123.4, 123.2 (2C), 29.0, 24.3. Anal. Calcd for
C27H17N‚0.5 H2O: C, 89.01; H, 4.95; N, 3.85. Found: C, 88.64; H,
4.65; N, 3.63.
3,2′-Dimethylene-2-phenyl-1,10-phenanthroline (16aH). Following
the procedure described for 9H, 1-tetralone (146 mg, 1 mmol) was
condensed with 8-amino-7-quinolinecarbaldehyde (172 mg, 1 mmol)
in absolute EtOH (12 mL) for 18 h. The brown, oily residue was
chromatographed on Al2O3 (30 g), eluting with EtOAc/hexane (1:1).
The second fraction afforded 16aH (232 mg, 82%) as a yellow solid,
mp 151-153 °C. 1H NMR (CDCl3): δ 9.22 (dd, 1H, H9, J ) 4.5, 1.8
Hz), 8.91 (d, 1H, H3′, J ) 7.8 Hz), 8.20 (dd, 1H, H7, J ) 8.1, 1.5 Hz),
7.97 (s, 1H, H4), 7.70 (AB quartet, 2H, H5,6), 7.59 (dd, 1H, H8, J )
8.1, 4.5 Hz), 7.44 (t, 1H, H4′, J ) 7.2 Hz), 7.36 (td, 1H, H5′, J ) 7.2,
0.9 Hz), 7.26 (m, 1H, H6′), 3.17 (t, 2H, CH2), 3.02 (t, 2H, CH2). 13C
Hz), 8.82 (d, 1H, H7, J ) 9.3 Hz), 8.39 (d, 1H, H5 6, J ) 8.7 Hz),
or
8.27 (d, 1H, H4, J ) 8.4 Hz), 8.24-8.18 (m, 4H, H8,d and H5 or 6), 7.99
(d, 2H, He, J ) 8.1 Hz), 7.85 (td, 2H, Hc, J ) 7.8, 1.5 Hz), 7.68 (t, 1H,
Hf ′, J ) 8.1 Hz), 7.39 (d, 2H, Ha, J ) 5.4 Hz), 7.21-7.09 (m, 4H,
H3,4′,b), 6.94 (td, 2H, H3′,5′, J ) 7.5, 1.5 Hz), 6.11 (d, 2H, H2′,6′, J ) 6.9
(20) The tpy protons are designated as follows: Ha ) H6, Hb ) H5, Hc )
H4, Hd ) H3, He ) H3′, and Hf ) H4′.

5858 Inorganic Chemistry, Vol. 40, No. 23, 2001
Bonnefous et al.
Hz). Anal. Calcd for C33H23N5ClRuPF6 - 0.5 H2O: C, 50.80; H, 3.08;
N, 8.98. Found: C, 50.68; H, 2.45; N, 8.81.
(38 mg, 48%), mp > 270 °C. 1H NMR (- 40 °C) (CD3CN): δ 10.20
(d, 1H, H9, J ) 5.1 Hz), 8.82 (d, 1H), 8.49 (d, 1H), 8.43 (d, 1H), 8.23
(m, 2H), 8.08 (d, 1H), 8.03 (t, 1H), 7.97-7.89 (m, 3H), 7.83 (d, 1H),
7.59 (t, 1H), 7.50 (t, 1H), 7.43 (t, 1H), 6.98 (m, 2H), 6.73 (t, 1H), 6.56
(t, 1H), 6.53 (d, 1H), 5.67 (d, 1H, H8′, J ) 7.5 Hz), 2.49 (m, 1H), 2.22
(m, 1H), 1.63 (m, 3H), 1.08 (m, 1H). Anal. Calcd for C35H25N5ClRuPF6
- 0.5 C7H8: C, 54.83; H, 3.44; N, 8.31. Found: C, 54.38; H, 3.19; N,
8.27.
[Ru(tpy)(10b)Cl](PF6) and [Ru(tpy)(10bH)Cl](PF6). Following the
procedure described for [Ru(tpy)(9)](PF6), 10bH (30 mg, 0.1 mmol)
was treated with [Ru(tpy)Cl3] (44 mg, 0.1 mmol) and refluxed for 5 h.
The first fraction afforded [Ru(tpy)(10b)](PF6) as a purple solid (11.8
mg, 15%), mp > 270 °C, which showed a mixture of two isomers by
1H NMR (CD3CN): δ 8.8-6.8 (complex pattern of overlapping peaks
accounting for 50 nonequivalent H), 6.42 (d, H8′), 6.15 (s, H4′). MS:
640 m/z (100, M + 1 - PF6). The second fraction afforded [Ru(tpy)-
(10bH)Cl](PF6) as a red solid (28.6 mg, 35%), mp > 270 °C, 1H NMR
(CD3CN): δ 10.46 (dd, 1H, J ) 4.2, 1.2 Hz), 8.83 (dd, 1H, J ) 8.1,
1.2 Hz), 8.42-8.34 (m, 2H), 8.21-8.19 (m, 3H), 8.00 (d, 1H, J ) 8.1
Hz), 7.89-7.84 (m, 3H), 7.72 (d, 1H, J ) 8.1 Hz), 7.65 (m, 2H), 7.49-
7.37 (m, 4H), 7.28-7.22 (m, 2H), 7.16-7.09 (m, 2H), 6,96 (t, 1H, J
) 7.8 Hz), 6.5 (s, 1H), 6.27 (dd, 1H, J ) 8.1 Hz). MS: m/z 676 (100,
M + 1 - PF6). Anal. Calcd for C37H25N5ClRuPF6: C, 54.11; H, 3.04;
N, 8.53. Found: C, 54.16; H, 2.89; N, 8.30.
[Ru(tpy)(10cH)Cl](PF6). Following the procedure described for [Ru-
(tpy)(9)](PF6), 10cH (35.6 mg, 0.1 mmol) was treated with [Ru(tpy)-
Cl3] (44 mg, 0.1 mmol) and refluxed for 5 h to give 41 mg (47%) of
the complex as a red solid, mp > 270 °C. 1H NMR (CD3CN): δ 10.42
(dd, 1H, J ) 5.4, 1.2 Hz), 8.88 (dd, 1H, J ) 8.4, 1.2 Hz), 8.45-8.40
(m, 3H), 8.31 (d, 1H, J ) 8.7 Hz), 8.17 (m, 2H), 8.10 (d, 1H, J ) 8.4
Hz), 7.94-7.83 (m, 3H), 7.70 (d, 1H, J ) 5.4 Hz), 7.57 (td, 1H, J )
8.4, 3.3 Hz), 7.38 (t, 1H, J ) 9 Hz), 7.32-7.26 (m, 3H), 7.19 (td, 1H,
J ) 6.9, 0.9 Hz), 7.11-7.03 (m, 3H), 6.91 (td, 1H, J ) 7.2, 1.5 Hz),
6.77-6.68 (m, 2H), 6.59 (s, 1H), 5.90 (dd, 1H, J ) 6.6, 0.6 Hz). MS:
m/z 726 (100, M + 1 - PF6).
[Ru(tpy)(16b)](PF6) and [Ru(tpy)(16bH)Cl](PF6). Following the
procedure described for [Ru(tpy)(9)](PF6), 16bH (59.2 mg, 0.2 mmol)
was treated with [Ru(tpy)Cl3] (88 mg, 0.2 mmol) and refluxed for 18
h. The first fraction afforded [Ru(tpy)(16b)](PF6) as a purple solid (9.5
1
mg, 6%), mp > 270 °C. H NMR (CD3CN):20 δ 8.63 (d, 2H, He, J )
8.1 Hz), 8.40 (d, 2H, Hd, J ) 8.1 Hz), 8.30 (s, 1H, H4), 8.26 (d, 1H,
H7, J ) 8.1 Hz), 8.13 (d, 1H, H5 or 6, J ) 9.0 Hz), 8.07 (t, 1H, Hf, J )
8.1 Hz), 7.98 (d, 1H, H5 6, J ) 9.0 Hz), 7.68 (d and t, 3H, H9, Hc),
or
7.23 (d and dd, 3H, H8, Ha), 6.87 (t, 2H, Hb, J ) 6.6 Hz), 6.51 (d, 1H,
H3′, J ) 6.9 Hz), 6.29 (t, 1H, H4′, J ) 7.2 Hz), 5.59 (d, 1H, H5′, J )
6.9 Hz), 3.57 (t, 2H, CH2), 3.21 (t, 2H, CH2), 2.27 (m, 2H, CH2). The
second fraction gave [Ru(tpy)(16bH)Cl](PF6) as a red solid (55.8 mg,
34%), mp > 270 °C. 1H NMR (CD3CN): δ 10.36 (d, 1H, H9, J ) 5.4
Hz), 8.82 (dd, 1H), 8.32 (m, 2H), 8.17 (dd, 1H), 8.09-8.06 (m, 3H),
8.04 (s, 1H), 7.99-7.93 (m, 3H), 7.68 (td, 1H), 7.61 (t, 1H), 7.34 (td,
1H), 7.12 (td, 1H), 6.90 (m, 2H), 6.79 (d, 1H), 6.67 (td, 1H), 5.45 (dd,
1H, H6′, J ) 7.2, 0.9 Hz), 2.49 (m, 1H), 2.22 (m, 1H), 1.63 (m, 3H),
1.08 (m, 1H). Anal. Calcd for C36H27N5ClRuPF6 - 0.75 H2O: C, 52.43;
H, 3.46; N, 8.50. Found: C, 52.49; H, 3.36; N, 8.37.
[Ru(tpy)(17)](PF6). Following the procedure described for [Ru(tpy)-
(9)](PF6), 17H (28 mg, 0.1 mmol) was treated with [Ru(tpy)Cl3] (44
mg, 0.1 mmol) and refluxed for 4.5 h to give 43 mg (57%) of [Ru-
[Ru(tpy)(10dH)Cl](PF6). Following the procedure described for
[Ru(tpy)(9)](PF6), 10dH (76 mg, 0.2 mmol) was treated with [Ru-
(tpy)Cl3] (88 mg, 0.2 mmol) and refluxed for 5.5 h to afford 60 mg
1
(tpy)(17)](PF6), mp > 270 °C. H NMR (CD3CN):20,21 δ 8.93 (s, 1H,
H7), 8.65 (d, 2H, He, J ) 8.1 Hz), 8.43-8.36 (m, 4H, H4, H8
and
9
or
1
(32%) of the complex as a red-brown solid, mp > 270 °C. H NMR
Hd), 8.13 (t, 1H, Hf, J ) 8.1 Hz), 8.11-8.05 (2d, 2H, H8 or 9 and H5 or
6), 8.00 (dd, 1H, H2, J ) 4.2, 0.9 Hz), 7.90 (d, 1H, H5 or 6, J ) 9 Hz),
7.64 (td, 2H, Hc, J ) 8.4, 1.2 Hz), 7.37 (dd, 1H, H3, J ) 8.1, 4.8 Hz),
7.28 (d, 1H, H10, J ) 8.1 Hz), 7.07 (d, 2H, Ha, J ) 5.1 Hz), 6.93 (t,
1H, H11, J ) 7.5 Hz), 6.74 (td, 2H, Hb, J ) 4.8, 1.5 Hz), 6.15 (d, 1H,
H12, J ) 7.2 Hz). MS: m/z 613 (100, M - PF6). Anal. Calcd for
C35H22N5RuPF6: C, 55.40; H, 2.90; N, 9.23. Found: C, 55.00; H, 2.91;
N, 8.93.
(CD3CN): δ 10.41 (d, 1H, J ) 4.8 Hz), 8.85 (d, 1H, J ) 9.0 Hz), 8.41
(m, 2H), 8.31-8.09 (m, 6H), 7.91 (t, 1H, J ) 6.9 Hz), 7.72 (d, 1H, J
) 7.8 Hz), 7.64 (d, 1H, J ) 5.1 Hz), 7.57 (t, 1H, J ) 7.8 Hz), 7.39 (m,
2H), 7.27-7.06 (m, 6H), 7.04 (t, 1H, J ) 6.6 Hz), 6.5 (d, 1H, J ) 7.5
Hz), 6.39-6.23 (m, 3H). MS: m/z 750 (100, M + 1 - PF6).
[Ru(tpy)(13)](PF6) and [Ru(tpy)(13H)(Cl)](PF6). A mixture of [Ru-
(tpy)Cl3] (54 mg, 0.123 mmol) and 13H (50 mg, 0.123 mmol) in EtOH/
H2O (3:1, 12 mL) was refluxed for 12 h. After cooling, NH4PF6 was
added, and the solvent was evaporated to dryness. The resulting mauve
residue was chromatographed on Al2O3 (40 g), eluting with CH2Cl2/
CH3CN (9:1). The first fraction afforded [Ru(13)(tpy)](PF6) as a purple
solid (30 mg, 46%), mp > 270 °C. 1H NMR (CD3CN): δ 8.74 (d, 2H,
He, J ) 7.31 Hz), 8.39-8.35 (m, 3H), 8.30-8.19 (m, 4H), 7.98 (d,
1H, J ) 9.14 Hz), 7.88-7.71 (m, 4H), 7.59 (d, 2H, J ) 7.31 Hz),
7.40-7.24 (m, 5H), 6.77 (t, 2H, J ) 7.31 Hz), 6.44 (d, 1H, J ) 9.14
Hz), 4.01 (t, 2H, CH2), 3.82 (t, 2H, CH2). The second fraction gave
[Ru(13H)(tpy)(Cl)](PF6) as a dark red solid (25 mg, 18%), mp > 270
X-ray Determinations. [Ru(tpy)(13)](PF6). A dark red column
having approximate dimensions 0.50 × 0.15 × 0.10 mm was mounted
in a random orientation on a Nicolet R3m/V automatic diffractometer.
The sample was placed in a steam of dry nitrogen gas at -50 °C, and
the radiation used was Mo K monochromatized by a highly ordered
graphite crystal. Final cell constants, and other information pertinent
to data collection and refinement, are listed in Table 4. The Laue
symmetry was determined to be 2/m, and from the systematic abscences
noted, the space group was shown unambiguously to be P21/n.
Intensities were measured using the ω scan technique, with the scan
rate depending on the count obtained in rapid prescans of each
reflection. Two standard reflections were monitored after every 2 h of
every 100 data collected, and these showed no significant variation.
During data reduction, Lorentz and polarization corrections were
applied, however, no correction for absorption was made due to the
small absorption coefficient.
The structure was solved by the SHELXTL direct methods program,
which revealed the positions of most of the nonhydrogen atoms in the
molecule. Remaining atoms were located in subsequent difference
Fourier syntheses. The usual sequence of isotropic and anisotropic
refinement was followed, after which all the hydrogens were entered
in ideal calculated positions and constrained to riding motion, with a
single variable isotropic temperature factor for all of them. After all
shift/esd ratios were less than 0.1, convergence was reached at the
agreement factors listed in Table 4. No unusually high correlations were
noted between any of the variables in the last cycle of full-matrix least-
1
°C. H NMR (CD3CN): δ 10.28 (d, 1H, H9, J ) 5.29 Hz), 8.84 (d,
1H, H7, J ) 7.76 Hz), 8.58 (d, 1H, Hd, J ) 6.35 Hz), 8.32 (d, 1H, Ha,
J ) 7.05 Hz), 8.32-8.25 (m, 5H), 8.19-8.11 (m, 2H), 8.04-8.00 (m,
3H), 7.87 (d, 1H, He or g, J ) 7.05 Hz), 7.02 (d, 1H, J ) 6.35 Hz), 6.92
(d, 1H, J ) 7.76 Hz), 6.78 (t, 1H, J ) 7.41 Hz), 6.61 (s, 1H, H3′), 6.56
(d, 1H, J ) 5.29 Hz),6.14 (t, 1H, J ) 7.41 Hz), 3.62 (t, 2H, CH2),
2.83 (t, 2H, CH2). The experiment was repeated using [Ru(tpy-d11)-
Cl3], and analogous results were obtained. A crystal of the N5Cl
complex was used for X-ray analysis.
[Ru(tpy)(16a)](PF6) and [Ru(tpy)(16aH)Cl](PF6). Following the
procedure described for [Ru(tpy)(9)](PF6), 16aH (28.2 mg, 0.1 mmol)
was treated with [Ru(tpy)Cl3] (44 mg, 0.1 mmol) and refluxed for 18
h. The first fraction gave [Ru(16a)(tpy)](PF6) as a purple solid (31 mg,
40%), mp > 270 °C. 1H NMR (CD3CN):20 δ 8.60 (d, 2H, Hc, J ) 7.8
Hz), 8.40 (d, 2H, Hd, J ) 8.1 Hz), 8.30 (dd, 1H, H7, J ) 8.1, 0.9 Hz),
8.23 (s, 1H, H4), 8.19 (d, 1H, H5 or 6, J ) 9.0 Hz), 8.06 (t, 1H, Hf, J )
8.1 Hz), 7.97 (d, 1H, H5 6, J ) 9.0 Hz), 7.86 (dd, 1H, H9, J ) 5.1,
or
0.9 Hz), 7.70 (td, 2H, Hc, J ) 8.1, 1.2 Hz), 7.29-7.25 (d and dd, 3H,
(21) The NMR atom numbering scheme designates N10 as H1, and each
successive nonbridgehead carbon atom on the periphery of the
molecule is then numbered sequentially proceeding away from the
bay region of the molecule.
H
8,a), 6.91 (td, 2H, Hb, J ) 6.9, 0.9 Hz), 6.54-6.44 (d and t, 2H, H3′,
4 ), 5.61 (d, 1H, H5′, J ) 6.9 Hz), 3.45 (t, 2H, CH2), 3.17 (t, 2H, CH2).
′
The second fraction afforded [Ru(tpy)(16aH)Cl](PF6) as a red solid

Cyclometalated Complexes of Ru(II)
Inorganic Chemistry, Vol. 40, No. 23, 2001 5859
Table 4. Data Collection and Processing Parameters for [Ru(tpy)(13)](PF6) and [Ru(tpy-d11)(13H)(Cl)](PF6)
[Ru(tpy)(13)](PF6)
[Ru(tpy-d11)(13H)(Cl)](PF6) + 1.5 C6H6 + CH3CN
chemical formula
space group
a, Å
b, Å
c, Å
C45H28F6N5PRu
P21/n (monoclinic)
28.1102(11)
8.4638(3)
31.2908(12)
90
107.505(1)
90
7099.9(5)
884.76
C45H18D11ClF6N5PRu-C11H12N
P-1 (triclinic)
11.7235(10)
14.5306(12)
14.5725(12)
75.536(1)
85.511(2)
79.812(1)
2364.3(3)
1090.50
R, deg
â, deg
γ, deg
V, Å3
formula weight, g/mol
formula units per cell, Z
density, g/cm3
absorption coefficent, cm-1
temp, °C
8
2
1.655
1.532
µ ) 5.62
µ ) 4.93
-50
-50
λ, radiation (Mo K), Å
number of refined parameters
number of observables
R1 ) ∑||Fo| - |Fc||/∑|Fo|
0.71073
581
0.71073
1045
8013
0.0581
0.1538
5322
0.0303
0.0728
awR2 ) [∑w(Fo2 - Fc2)2/∑w(Fo )2]1/2
2
a For [Ru(tpy)(13)](PF6), w ) [σ(Fo)2 + (0.0333P)2 + (11.656P)]-1, and for [Ru(tpy-d11)(13H)(Cl)](PF6), w ) [σ(Fo)2 + (0.1134P)2 + (4456P)]-1
,
2
where P ) (Fo + 2Fc2)/3.
squares refinement, and the final difference density map showed a
maximum peak of about 0.78 e/Å3. All calculations were made using
Bruker’s SHELXS-97 (Sheldrick, 1997) series of crystallographic
programs.22
listed in Table 4. The Laue symmetry was determined to be -1, and
the space group was shown to be either P1 or P-1. The anion was
found to be massively disordered, and the three major orientations were
refined as individual rigid bodies. One of the benzene solvent molecules
was found to be disorderd 50:50 over two staggered orientations, and
these were also entered as ideal rigid bodies. One site in the lattice
was found to be occupied 50% of the time by benzene and 50% of the
time by a pair of acetonitrile molecules. A combination of rigid bodies
and distance constraints was used to model this area.
[Ru(tpy)(13H)(Cl)](PF6). All measurements were made with a
Siemens SMART platform diffractometer equipped with a 1K CCD
area detector. A hemisphere of data (1271 frames at 5 cm detector
distance) was collected using a narrow-frame method, with scan widths
of 0.30° in ω and an exposure time of 30 s/frame. The first 50 frames
were remeasured at the end of data collection to monitor instrument
and crystal stability, and the maximum correction on I was < 1%. The
data were integrated using the Siemens SAINT program, with the
intensities corrected for Lorentz factor, polarization, air absorption, and
absorption due to variation in the path length through the detector
faceplate. A ψ scan absorption correction was applied based on the
entire data set. Redundant reflections were averaged. Final cell constants
were refined using 6869 reflections having I > 10σ(I), and these, along
with other information pertinent to data collection and refinement, are
Acknowledgment. We would like to thank the Robert A.
Welch Foundation (E-621) and the National Science Founda-
tion (CHE-9714998) for financial support of this work. We
would also like to thank Dr. James Korp for assistance with
the X-ray analysis, and one of the referees for helpful comments.
Supporting Information Available: X-ray crystallographic files
for [Ru(tpy)(13)](PF6) and [Ru(tpy-d11)(13H)(Cl)](PF6) in CIF format.
This material is available free of charge via the Internet at http://
pubs.acs.org.
(22) Sheldrick, G. M. In Crystallographic Computing 3; Sheldrick, G. M.,
Kruger, C., Goddard, R., Eds.; Oxford University Press: Oxford, U.
K., 1985, pp 175-189.
IC0102844