Electrophilic substitution reactions at the phenyl ring of the chelated 2-(2′-pyridyl)phenyl ligand bound to ruthenium(II) or osmium(II)

Article abstract of DOI:10.1021/om990232a

Reaction between (PyPh)₂Hg (PyPh = 2-(2′-pyridyl)phenyl) and MHCl(CO)(PPh₃)₃ proceeds smoothly to form M(η²-PyPh)Cl(CO)(PPh₃)₂ (M = Ru (1a); M = Os (1b)). In both complexes the PyPh ligand is bound as a stable five-membered chelate ring. The chloride ligand in these complexes can be removed through reaction with a silver salt and other ligands then introduced. In this way the compounds M(η²-PyPh)I(CO)(PPh₃)₂ (M = Ru (2a); M = Os (2b)), [M(η²-PyPh)(CO)₂(PPh₃)₂]SbF ₆ (M = Ru (3a); M = Os (3b)), and M(η²-PyPh)(η²-S₂CNMe ₂)-(CO)(PPh₃) (M = Ru (4a); M = Os (4b)) have been prepared. The coordinated PyPh ligand in 1a and 1b is activated by the metal toward electrophilic substitution at the phenyl ring. Nitration occurs in both the phenyl 4- and 6-positions of 1a or 1b, i.e., ortho and para to the metal, to give M(η²-PyPh-4,6-(NO₂)₂)Cl(CO)(PPh ₃)₂ (M = Ru (5a); M = Os (5b)). Under appropriate conditions the mono-nitrated derivative, Os(η²-PyPh-4-NO₂)Cl(CO)(PPh₃)₂ (5c), can also be isolated. Bromination of 1a or 1b occurs in the phenyl 4-position, i.e., para to the metal, to give M(η²-PyPh-4-Br)Cl(CO)(PPh₃)₂ (M = Ru (6a); M = Os (6b)). With excess brominating agent ([PyrH][Br₃]) and a longer reaction time the unusual mixed triphenylphosphine/pyridine complex, Os(η²-PyPh-4-Br)Cl(CO)(Pyr)(PPh₃) (6c) (Pyr = pyridine), is formed. The brominated osmium substrate (6b) can be lithiated through reaction with BuLi. Although this intermediate has not been isolated, further treatment with the electrophiles CO₂/H⁺ or Bu₃SnCl forms Os(η²-PyPh-4-CO₂H)Cl(CO)(PPh₃)₂ (7a) or Os(η²-PyPh-4-SnBu₃)Cl(CO)(PPh₃)₂ (Tb), respectively. The functionalized pyridylphenyl ligand in 6a can be removed by heating with acid, to give 2′-(3-bromophenyl)pyridine, in modest isolated yield. The structures of [Os(η²-PyPh)(CO)₂(PPh₃) ₂]SbF₆ (3b), Os(η²-PyPh)(η²-S₂-CNMe ₂)(CO)(PPh₃) (4b), Os(η²-PyPh-4-NO₂)Cl(CO)(PPh₃)₂ (5c), Os(η²-PyPh-4-Br)Cl(CO)-(PPh₃)₂ (6b), and Os(η²-PyPh-4-Br)Cl(CO)(Pyr)(PPh₃) (6c) have all been determined by X-ray crystal structure analyses.

Full text of DOI:10.1021/om990232a

Organometallics 1999, 18, 2813-2820
2813
Electr op h ilic Su bstitu tion Rea ction s a t th e P h en yl Rin g
of th e Ch ela ted 2-(2′-P yr id yl)p h en yl Liga n d Bou n d to
Ru th en iu m (II) or Osm iu m (II)
Alex M. Clark, Clifton E. F. Rickard, Warren R. Roper,* and L. J ames Wright*
Department of Chemistry, The University of Auckland, Private Bag 92019,
Auckland, New Zealand
Received April 5, 1999
Reaction between (PyPh)2Hg (PyPh ) 2-(2′-pyridyl)phenyl) and MHCl(CO)(PPh3)3 proceeds
smoothly to form M(η2-PyPh)Cl(CO)(PPh3)2 (M ) Ru (1a ); M ) Os (1b)). In both complexes
the PyPh ligand is bound as a stable five-membered chelate ring. The chloride ligand in
these complexes can be removed through reaction with a silver salt and other ligands then
introduced. In this way the compounds M(η2-PyPh)I(CO)(PPh3)2 (M ) Ru (2a ); M ) Os (2b)),
[M(η2-PyPh)(CO)2(PPh3)2]SbF6 (M ) Ru (3a ); M ) Os (3b)), and M(η2-PyPh)(η2-S2CNMe2)-
(CO)(PPh3) (M ) Ru (4a ); M ) Os (4b)) have been prepared. The coordinated PyPh ligand
in 1a and 1b is activated by the metal toward electrophilic substitution at the phenyl ring.
Nitration occurs in both the phenyl 4- and 6-positions of 1a or 1b, i.e., ortho and para to the
metal, to give M(η2-PyPh-4,6-(NO2)2)Cl(CO)(PPh3)2 (M ) Ru (5a ); M ) Os (5b)). Under
appropriate conditions the mono-nitrated derivative, Os(η2-PyPh-4-NO2)Cl(CO)(PPh3)2 (5c),
can also be isolated. Bromination of 1a or 1b occurs in the phenyl 4-position, i.e., para to
the metal, to give M(η2-PyPh-4-Br)Cl(CO)(PPh3)2 (M ) Ru (6a ); M ) Os (6b)). With excess
brominating agent ([PyrH][Br3]) and a longer reaction time the unusual mixed triph-
enylphosphine/pyridine complex, Os(η2-PyPh-4-Br)Cl(CO)(Pyr)(PPh3) (6c) (Pyr ) pyridine),
is formed. The brominated osmium substrate (6b) can be lithiated through reaction with
BuLi. Although this intermediate has not been isolated, further treatment with the
electrophiles CO2/H+ or Bu3SnCl forms Os(η2-PyPh-4-CO2H)Cl(CO)(PPh3)2 (7a ) or Os(η2-
PyPh-4-SnBu3)Cl(CO)(PPh3)2 (7b), respectively. The functionalized pyridylphenyl ligand in
6a can be removed by heating with acid, to give 2′-(3-bromophenyl)pyridine, in modest
isolated yield. The structures of [Os(η2-PyPh)(CO)2(PPh3)2]SbF6 (3b), Os(η2-PyPh)(η2-S2-
CNMe2)(CO)(PPh3) (4b), Os(η2-PyPh-4-NO2)Cl(CO)(PPh3)2 (5c), Os(η2-PyPh-4-Br)Cl(CO)-
(PPh3)2 (6b), and Os(η2-PyPh-4-Br)Cl(CO)(Pyr)(PPh3) (6c) have all been determined by X-ray
crystal structure analyses.
In tr od u ction
different aryl groups including the 2-(2′-pyridyl)phenyl
ligand, which is the subject of this paper.2
Many metal complexes containing the PyPh (2-(2′-
pyridyl)phenyl) ligand have been prepared previously
by direct metalation of 2-phenylpyridine. Metalation of
the phenyl ring invariably occurs in the ortho position,
and the resulting five-membered chelate ring is usually
very stable.1 We have shown that a convenient high-
yield route to the coordinatively unsaturated aryl
complexes M(Ar)Cl(CO)(PPh3)2 (M ) Ru or Os) involves
the reaction of MHCl(CO)(PPh3)3 with Ar2Hg. This
reaction is general and works well for a wide range of
In recent studies we have shown that simple aryl
ligands in M(Ar)Cl(CO)(PPh3)2 or the corresponding
saturated complexes, M(Ar)Cl(CO)L(PPh3)2 (L ) CO,
CNR), are strongly activated by the metal toward
electrophilic aromatic substitution reactions.3 While the
metal-carbon bond remains intact during many of these
reactions involving mild reagents, the use of more
vigorous reagents can cause bond cleavage. When the
aryl ligand contains a functional group which coordi-
nates to the metal and forms a chelate ring, the metal-
carbon bond is considerably more resistant to attack by
external reagents. We have previously reported the
preparation of Os(η2-Qn)Cl(CO)(PPh3)2 (Qn ) 8-quinolyl).4
(1) (a) Kasahara, A. Bull. Chem. Soc. J pn 1968, 41, 1272. (b)
Chassot, L.; von Zewelsky, A. Inorg. Chem. 1987, 26, 2814. (c) Steel,
P. J .; Caygill, G. B. J . Organomet. Chem. 1987, 327, 101. (d) Garces,
F. O.; King, K. A.; Watts, R. J . Inorg. Chem. 1988, 27, 3464. (e) Craig,
C. A.; Watts, R. J . Inorg. Chem. 1989, 28, 309. (f) Zilian, A.; Marder,
U.; von Zelewski, A.; Gu¨del, H. U. J . Am. Chem. Soc. 1989, 111, 3855.
(g) Craig, C. A.; Garces, F. O.; Watts, R. J .; Palmans, R.; Frank, A. J .
Coord. Chem. Rev. 1990, 97, 193. (h) Steel, P. J .; Caygill, G. B. J .
Organomet. Chem. 1990, 395, 359. (i) Constable, E. C.; Cargil Thomp-
son, A. M. W.; Leese, T. A.; Reese, D. G. F.; Tocher, D. A. Inorg. Chim.
Acta 1991, 182, 93. (j) Djukic, J .-P.; Do¨tz, K. H.; Pfeffer, M.; Cian, A.
D.; Fischer, J . Organometallics 1997, 16, 5171. (k) Guari, Y.; Sabo-
Etienne, S.; Chaudret, B. J . Am. Chem. Soc. 1998, 120, 4228.
(2) (a) Roper, W. R.; Wright, L. J . J . Organomet. Chem. 1977, 142,
C1. (b) Rickard, C. E. F.; Roper, W. R.; Taylor, G. E.; Waters, J . M.;
Wright, L. J . J . Organomet. Chem. 1990, 389, 375. (c) Ng, M. M. P.;
Roper, W. R.; Wright, L. J . Organometallics 1994, 13, 2563. (d) Clark,
G. R.; Ng, M. M. P.; Roper, W. R.; Wright, L. J . J . Organomet. Chem.
1995, 491, 219. (e) Hu¨bler, K.; Hu¨bler, U.; Roper, W. R.; Wright, L. J .
J . Organomet. Chem. 1996, 526, 199.
(3) Clark, G. R.; Headford, C. E. L.; Roper, W. R.; Wright, L. J .; Yap,
V. P. D. Inorg. Chim. Acta 1994, 220, 261.
10.1021/om990232a CCC: $18.00 © 1999 American Chemical Society
Publication on Web 06/29/1999

2814 Organometallics, Vol. 18, No. 15, 1999
Clark et al.
a
Ta ble 1. In fr a r ed Da ta (cm -1
) for New
Sch em e 1
2-(2′-P yr id yl)p h en yl Com p lexes
complex
ν(CdO)
other bands
Ru(η2-PyPh)Cl(CO)(PPh3)2 (1a ) 1919 s
Os(η2-PyPh)Cl(CO)(PPh3)2 (1b)
Ru(η2-PyPh)I(CO)(PPh3)2 (2a )
Os(η2-PyPh)I(CO)(PPh3)2 (2b)
1898 s
1915 s
1902 s
[Ru(η2-PyPh)(CO)2(PPh3)2]SbF6 1994, 2049 s 999, 656 s (SbF6)
(3a )
[Os(η2-PyPh)(CO)2(PPh3)2]SbF6
(3b)
1953, 2023 s 999, 660 s (SbF6)
Ru(η2-PyPh)(η2-S2CNMe2)(CO)- 1921 s
1504 m
(dithiocarbamate)
1518 m
(dithiocarbamate)
1530, 1506 m
(NO2)
1531, 1504 m
(NO2)
1496 m (NO2)
The Qn ligand contains a nitrogen placed suitably for
coordination to the metal, forming a four-membered
chelate ring. The 8-quinolyl ring system was found to
be very activated toward electrophilic aromatic substi-
tution and readily underwent bromination or nitration
in the position para to the osmium-carbon bond.5 In
addition, it was found that the bromoquinolyl complex
Os(η2-Qn-5-Br)Cl(CO)(PPh3)2 could be lithiated with
BuLi without cleaving the osmium-carbon bond, thus
making possible introduction of a variety of functional
groups.5 Up to this point the usual method for preparing
functionalized aryl ligands has been to include the
functionality prior to metalation.6
(PPh3) (4a )
Os(η2-PyPh)(η2-S2CNMe2)(CO)- 1903 s
(PPh3) (4b)
Ru(η2-PyPh-(4,6-(NO2)2)Cl(CO)- 1948 s
(PPh3)2 (5a )
Os(η2-PyPh-(4,6-(NO2)2)Cl(CO)- 1929 s
(PPh3)2 (5b)
Os(η2-PyPh-4-NO2)Cl(CO)(PPh3)2 1915 s
(5c)
Ru(η2-PyPh-4-Br)Cl(CO)(PPh3)2 1927 s
(6a )
Os(η2-PyPh-4-Br)Cl(CO)(PPh3)2 1911 s
(6b)
Os(η2-PyPh-4-Br)Cl(CO)(Pyr)-
(PPh3) (6c)
1907 s
1906 s
1904 s
Os(η2-PyPh-4-CO2H)Cl(CO)-
(PPh3)2 (7a )
1673 s (CO2H)
Os(η2-PyPh-4-SnBu3)Cl(CO)-
(PPh3)2 (7b)
Our main interest in using a metal-ligand fragment
as an activating/directing substituent in electrophilic
aromatic substitution reactions is to access complexes
with specially substituted organometallic ligands, which
in turn offer a wide scope for further ligand elaboration.6g
It should not be overlooked, however, that removal of
the substituted ligands from the metal could, in prin-
ciple, constitute a route to unusually substituted organ-
ics that are difficult to prepare by other means. Accord-
ingly, one example of the cleavage of a substituted
ligand is briefly explored in this work.
a
Spectra were recorded as Nujol mulls between KBr plates.
In this paper we report (i) the preparation of 2-(2′-
pyridyl)phenyl complexes of ruthenium(II) and osmium-
(II), (ii) a study of the electrophilic substitution reactions
occurring at the 2-(2′-pyridyl)phenyl ligands, (iii) lithia-
tion followed by further derivatization of the bromo-
substituted derivatives, (iv) an observation of the re-
placement with pyridine of one triphenylphosphine, in
a bis(triphenylphosphine) complex, through use of the
brominating reagent [PyrH][Br3], and (v) an example
of the removal from the metal of a functionalized ligand
fragment as an unusually substituted 2-(phenyl)pyri-
dine.
Figu r e 1. Molecular structure of [Os(η2-PyPh)(CO)2(PPh3)2]-
SbF6 (3b) (cation only) with thermal ellipsoids at the 50%
probability level.
data is presented in the Experimental Section, and the
numbering system used for NMR assignments and the
naming of compounds is as depicted in the molecular
structure diagrams, Figures1-5). The 2-(2′-pyridyl)-
phenyl ligand binds to the metal in a bidentate fashion,
forming a five-membered chelate ring which is robust,
and attempts to displace the nitrogen from the metal
center through addition of other potential ligands such
as CO or CNR failed, even under forcing conditions.
Likewise, introduction of the powerfully chelating ligand
dimethyldithiocarbamate did not displace the nitrogen
atom (see below).
Der iva tives of 1a a n d 1b th r ou gh Ch lor id e Re-
p la cem en t. The chloride ligand in either 1a or 1b is
relatively labile and can be easily removed by treatment
in solution with AgSbF6. Subsequent treatment of the
cationic intermediate (which was not isolated) with
anionic or neutral donors provides a simple route to new
Resu lts a n d Discu ssion
Tr a n sm eta la tion . Treatment of MHCl(CO)(PPh3)3
with PyPh2Hg forms M(η2-PyPh)Cl(CO)(PPh3)2 (M ) Ru
(1a ), Os (1b)) (see Scheme 1; IR data for these and all
other new compounds are collected in Table 1, NMR
(4) Clark, A. M.; Rickard, C. E. F.; Roper, W. R.; Wright, L. J . J .
Organomet. Chem. 1997, 545-6, 619.
(5) Clark, A. M.; Rickard, C. E. F.; Roper, W. R.; Wright, L. J .
Organometallics 1998, 17, 4535.
(6) (a) Kawata, N.; Mizoroki, T.; Ozaki, A. Bull. Chem. Soc. J pn.
1974, 47, 1807. (b) Reveco, P.; Schmehl, R. H.; Cherry, W. R.; Fronczek,
F. R.; Selbin, J . Inorg. Chem. 1985, 24, 4078. (c) Debaerdemaeker, T.;
Stapp, B.; Brune, H. A. Acta Crystallogr. 1987, C43, 473. (d) Tam, W.;
Calabrese, J . C. Chem. Phys. Lett. 1988, 144, 79. (e) Vicente, J .; Arcas,
A.; Borrachero, M. V.; Mol´ıns, E.; Miravitlles, C. J . Organomet. Chem.
1992, 441, 487. (f) Kim, Y.-J .; Sato, R.; Maruyama, T.; Osakada, K.;
Yamamoto, T. J . Chem. Soc., Dalton Trans. 1994, 943. (g) Clark, G.
R.; Rickard, C. E. F.; Roper, W. R.; Wright, L. J .; Yap, V. P. D. Inorg.
Chim. Acta 1996, 251, 65. (h) Forsyth, R.; Pyman, F. L. J . Chem. Soc.
1926, 2912.

Chelated PyPh Ligand Bound to Ru(II) or Os(II)
Organometallics, Vol. 18, No. 15, 1999 2815
F igu r e 4. Molecular structure of Os(η2-PyPh-4-Br)Cl(CO)-
(PPh3)2 (6b) with thermal ellipsoids at the 50% probability
level.
Figu r e 2. Molecular structure of Os(η2-PyPh)(η2-S2CNMe2)-
(CO)(PPh3) (4b) (one enantiomer only) with thermal el-
lipsoids at the 50% probability level.
F igu r e 5. Molecular structure of Os(η2-PyPh-4-Br)Cl(CO)-
(Pyr)(PPh3) (6c) (one enantiomer only) with thermal el-
lipsoids at the 50% probability level.
F igu r e 3. Molecular structure of Os(η2-PyPh-4-NO2)Cl-
(CO)(PPh3)2 (5c) with thermal ellipsoids at the 50% prob-
ability level.
Sch em e 2
derivatives (see Scheme 2). Reaction with sodium iodide
gives the products of simple halide exchange, M(η2-
PyPh)I(CO)(PPh3)2 (M ) Ru (2a ); M ) Os (2b)), while
reaction with carbon monoxide gives the dicarbonyl salts
[M(η2-PyPh)(CO)2(PPh3)2]SbF6 (M ) Ru (3a ); M ) Os
(3b)). Sodium dimethyldithiocarbamate adds to the
metal center rapidly at room temperature, and then in
a slower step which is accelerated by heating triph-
enylphosphine is displaced and the dimethyldithiocar-
bamate ligand coordinates in a bidentate fashion to give
M(η2-PyPh)(η2-S2CNMe2)(CO)(PPh3) (M ) Ru (4a ); M
) Os (4b)).
Electr op h ilic Ar om a tic Su bstitu tion . Nitration of
free 2-phenylpyridine has been reported to occur in the
phenyl ring to give two mono-nitrated isomers, the
major isomer being that with the nitro group para to
the ring junction. The conditions for this nitration
involve heating 2-phenylpyridine nitrate in concentrated
H2SO4 at 100 °C for 30 min.6h In contrast, the metal-
bound 2-phenylpyridine ligand in complexes 1a and 1b
is highly activated toward electrophilic aromatic nitra-
tion. The activated positions are on the phenyl ring,
ortho and para to the metal substituent. Nitration of
1a or 1b with excess Cu(NO3)2 in acetic anhydride for
1 h at room temperature gives exclusively the dinitrated

2816 Organometallics, Vol. 18, No. 15, 1999
Clark et al.
Sch em e 3
Sch em e 5
reaction times. Under these conditions, 6b gave the
unusual product Os(η2-PyPh-4-Br)Cl(CO)(Pyr)(PPh3)
(6c), in which not only is the PyPh ligand brominated
but in addition pyridine replaces one triphenylphos-
phine ligand (see Scheme 4). It appears that one of the
triphenylphosphine ligands dissociates and is oxidized
by the excess bromine, leaving only a pyridine molecule
to occupy the vacant site. This approach could offer an
interesting general route to mixed triphenylphosphine/
pyridine complexes of osmium(II), but we have not yet
explored this further.
Sch em e 4
Lith ia tion . It was found that lithiation of the phenyl
ring of complex 6b could be achieved by reaction with
excess BuLi at 0 °C. Although the intermediate product,
Os(η2-PyPh-4-Li)Cl(CO)(PPh3)2, was not isolated, two
derivatives have been fully characterized (see Scheme
5). Reaction of this intermediate with CO2/H+ gives the
carboxylic acid derivative, Os(η2-PyPh-4-CO2H)Cl(CO)-
(PPh3)2 (7a ). Similarly, treatment of the intermediate
with an excess of Bu3SnCl gives Os(η2-PyPh-4-SnBu3)-
Cl(CO)(PPh3)2 (7b).
Str u ctu r es. Bond distances and angles for 3b, 4b,
5c, 6b, and 6c are given in Tables3-7, respectively. The
compounds 3b, 4b, 5c, 6b, and 6c all exhibit essentially
octahedral coordination geometries, and 3b, 5c, and 6b
all have mutually trans triphenylphosphine ligands,
with angles P(1)-Os-P(2) close to 180° (176.78(6)°,
174.97(3)°, and 177.13(7)°, respectively). The structure
of 6c is very similar to that of 6b, except that a pyridine
ligand replaces one of the triphenylphosphine ligands.
As a consequence of the introduction of the pyridine,
the remaining Os-P distance in 6c is shortened by more
than 0.06 Å compared to the Os-P distances in 6b. On
the other hand, the individual bond lengths and angles
within the 2-(2′-pyridyl)phenyl ligands in 3b, 4b, 5c,
6b, and 6c show little variation. The Os-C bond lengths
in 4b, 5c, 6b, and 6c are remarkably similar (2.077(6),
2.041(4), 2.050(9) and 2.044(5) Å, respectively), even
though the substitution patterns on the phenyl rings
differ considerably and the ancillary ligands are not the
same. The corresponding Os-C distance in 3b is longer
(2.125(6) Å), presumably because this compound is
cationic and also the trans ligand is CO. The Os-N bond
in 3b is also shorter (2.127(6) Å) than the corresponding
distances in 4b, 5c, 6b, and 6c (2.167(6), 2.153(3), 2.157-
(7), and 2.173(4) Å, respectively). Presumably this is a
result of the cationic nature of the metal center in 3b.
Dem eta la tion . Cleavage of the brominated 2-phe-
nylpyridine ligand from 6a or 6b with HCl was inves-
tigated. For the osmium complex, 6b, only trace amounts
of 2′-(3-bromophenyl)pyridine (8) were released from the
metal. However, when the ruthenium substrate, 6a , was
dissolved in toluene and heated under reflux overnight
with a large excess of concentrated HCl, the complex
was decomposed entirely, and a modest yield of 2′-(3-
products M(η2-PyPh-4,6-(NO2)2)Cl(CO)(PPh3)2 (M ) Ru
(5a ); M ) Os (5b)) (see Scheme 3). While the osmium
complex 5b can be prepared in reasonable yield (36%),
the ruthenium complex 5a is produced in lower yield
(18%), even when the reaction is performed at 0 °C.
Under similar nitrating conditions, but utilizing a
very short reaction time, it was possible to prepare the
para-substituted, mono-nitrated osmium complex, Os-
(η2-PyPh-4-NO2)Cl(CO)(PPh3)2 (5c), albeit in low yield.
None of the 6-substituted product, Os(η2-PyPh-6-NO2)-
Cl(CO)(PPh3)2, was observed, presumably because the
4-position is more accessible to attack than the 6-posi-
tion. Clearly, introduction of the first nitro group does
not significantly deactivate the phenyl ring toward
further nitration.
Bromination of the metal-bound 2-phenylpyridine
ligand in complexes 1a and 1b also occurs more readily
than does bromination of simple phenyl derivatives.
Moreover, the reaction is highly selective, and only one
isomer is formed, that in which the bromine is intro-
duced para to the metal. Room-temperature bromina-
tion of 1a or 1b by addition of 1 equiv of bromine (in
the form of [PyrH][Br3]), in the presence of a catalytic
quantity of iron powder, gives rise to the mono-bromi-
nated products, M(η2-PyPh-4-Br)Cl(CO)(PPh3)2 (M ) Ru
(6a ); M ) Os (6b)) (see Scheme 4). Good yields are
obtained in both cases. However, unlike the nitration
reaction, no dibrominated products were observed even
when an excess of [PyrH][Br3] was used and with longer

Chelated PyPh Ligand Bound to Ru(II) or Os(II)
Organometallics, Vol. 18, No. 15, 1999 2817
Ta ble 2. Cr ysta l a n d Refin em en t Da ta for 3b, 4b, 5c, 6b, a n d 6c
3b‚1/2CH2Cl2
4b
5c
6b
6c‚CHCl3
formula
C49H38NO2P2Os‚SbF6‚
1/2CH2Cl2
1203.16
triclinic
P1h
11.8966(2)
13.9035(2)
15.1958(2)
90.949(1)
98.017(1)
101.46(1)
24636.70(6)
2
C33H29N2OOsPS2
C48H37ClN2O3OsP2
C48H37BrClNOOsP2
C35H26BrClN2OOsP2‚
CHCl3
946.48
monoclinic
P21/c
10.679(1)
22.350(3)
14.803(2)
molecular wt
cryst syst
space group
a, Å
b, Å
c, Å
754.87
monoclinic
C2/c
11.3840(1)
15.3789(1)
34.5340(1)
977.39
triclinic
P1h
1011.29
triclinic
P1h
11.2393(2)
12.2801(2)
16.0510(3)
73.292(1)
76.092(1)
73.717(1)
2005.73(6)
2
1.618
972
3.371
1.78-27.47
11.3911(1)
12.0481(1)
17.3575(1)
76.656(1)
78.776(1)
11.193(1)
2234.19(4)
2
1.503
996
3.91
1.8-28.2
R, deg
â, deg
93.128(1)
90.896(1)
γ, deg
V , Å3
6036.98(7)
8
1.661
2976
4.44
2.2-27.4
3532.71(7)
4
1.780
1836
5.12
1.6-27.4
Z
d(calc), g cm-3
F(000)
1.640
1174
3.34
1.3-28.3
µ, mm-1
θ (min-max),
deg
unique reflns
no. of obsd reflns
I > 2σ(I)
cryst size, mm
A, (min, max)
no. of variables
in LS
10740
9288
13053
12701
8732
7958
9847
8134
7702
6466
0.50 × 0.22 × 0.09
0.286, 0.753
571
0.20 × 0.20 × 0.19
0.470, 0.485
725
0.48 × 0.23 × 0.06
0.2945, 0.8233
514
0.32 × 0.08 × 0.05
0.367, 0.828
496
0.40 × 0.10 × 0.08
0.234, 0.685
414
goodness of fit
0.950
1.005
1.034
0.698
1.040
on F2
R (obsd data)
wR2 (all data)
diff map
0.0512
0.1469
-1.99, +1.64
0.0338
0.0812
-1.15, +0.58
0.0285
0.0736
1.129, 1.840
0.0511
0.1788
-1.71, +2.07
0.0387
0.0922
-1.88, +2.01
(min, max),
e Å-3
Ta ble 3. Selected Bon d Dista n ces (Å) a n d An gles
(d eg) for Com p lex 3b
Ta ble 5. Selected Bon d Dista n ces (Å) a n d An gles
(d eg) for Com p lex 5c
Interatomic Distances
Interatomic Distances
Os-C(7)
Os-C(8)
Os-C(1)
1.904(7)
1.912(6)
2.125(6)
Os-N
Os-P(2)
Os-P(1)
2.127(6)
2.4038(15)
2.4087(15)
Os-C(7)
Os-C(1)
Os-N(1)
1.848(4)
2.041(4)
2.153(3)
Os-Cl
Os-P(2)
Os-P(1)
2.5204(9)
2.3894(8)
2.4172(8)
Interatomic Angles
Interatomic Angles
C(7)-Os-C(8)
C(7)-Os-C(1)
C(8)-Os-C(1)
C(7)-Os-N
95.2(3)
168.4(3)
96.5(3)
90.2(3)
174.6(3)
78.2(3)
C(1)-Os-P(2)
89.73(16)
89.56(16)
92.7(2)
89.70(19)
87.09(16)
89.33(16)
176.79(6)
C(7)-Os-C(1)
C(7)-Os-N(1)
C(1)-Os-N(1)
C(7)-Os-P(2)
C(1)-Os-P(2)
N(1)-Os-P(2)
C(7)-Os-P(1)
C(1)-Os-P(1)
91.54(16)
169.85(14)
78.42(14)
89.68(12)
91.25(9)
88.98(7)
93.19(11)
92.80(9)
N(1)-Os-P(1)
C(7)-Os-Cl
C(1)-Os-Cl
N(1)-Os-Cl
P(2)-Os-Cl
P(1)-Os-Cl
P(2)-Os-P(1)
88.91(7)
98.76(12)
169.69(11)
91.29(8)
89.29(3)
86.19(3)
N-Os-P(2)
C(7)-Os-P(1)
C(8)-Os-P(1)
C(1)-Os-P(1)
N-Os-P(1)
C(8)-Os-N
C(1)-Os-N
C(7)-Os-P(2)
C(8)-Os-P(2)
90.3(2)
91.12(19)
P(2)-Os-P(1)
174.97(3)
Ta ble 4. Selected Bon d Dista n ces (Å) a n d An gles
(d eg) for Com p lex 4b
Ta ble 6. Selected Bon d Dista n ces (Å) a n d An gles
(d eg) for Com p lex 6b
Interatomic Distances
Interatomic Distances
Os(1)-C(10)
Os(1)-C(1)
Os(1)-N(1)
1.844(7)
2.077(6)
2.167(6)
Os(1)-P(1)
Os(1)-S(2)
Os(1)-S(1)
2.3263(16)
2.4556(17)
2.4874(17)
Os-C(7)
Os-C(1)
Os-N
1.865(10)
2.050(9)
2.157(7)
2.527(2)
Os-P(2)
Os-P(1)
Br-C(4)
2.3801(19)
2.3958(19)
1.903(9)
Os-Cl
Interatomic Angles
C(10)-Os(1)-C(1)
94.1(3)
N(1)-Os(1)-S(2)
P(1)-Os(1)-S(2)
C(10)-Os(1)-S(1)
C(1)-Os(1)-S(1)
84.49(16)
167.83(6)
96.3(2)
160.25(18)
91.13(15)
97.27(6)
Interatomic Angles
C(10)-Os(1)-N(1) 171.2(3)
C(7)-Os-C(1)
C(7)-Os-N
92.3(4)
170.5(3)
78.3(3)
90.4(3)
91.4(2)
89.02(17)
92.2(3)
89.6(2)
N-Os-P(1)
P(2)-Os-P(1)
C(7)-Os-Cl
C(1)-Os-Cl
N-Os-Cl
P(2)-Os-Cl
P(1)-Os-Cl
88.54(17)
177.13(7)
97.6(3)
170.0(2)
91.9(2)
C(1)-Os(1)-N(1)
C(10)-Os(1)-P(1)
C(1)-Os(1)-P(1)
N(1)-Os(1)-P(1)
C(10)-Os(1)-S(2)
C(1)-Os(1)-S(2)
77.5(3)
92.3(2)
C(1)-Os-N
99.08(18) N(1)-Os(1)-S(1)
91.43(15) P(1)-Os(1)-S(1)
93.4(2)
C(7)-Os-P(2)
C(1)-Os-P(2)
N-Os-P(2)
C(7)-Os-P(1)
C(1)-Os-P(1)
S(2)-Os(1)-S(1)
71.41(6)
90.24(7)
88.34(7)
91.25(18)
bromophenyl)pyridine (25%) was obtained. The ruthe-
nium-containing product formed during this reaction
was not fully characterized, but IR absorption bands
were consistent with the formation of the triply chloro-
bridged dimer [(Ph3P)Cl(OC)Ru(µ-Cl)3Ru(CO)(PPh3)2].7
Although 2′-(3-bromophenyl)pyridine cannot be pre-
pared by direct bromination of 2-(phenyl)pyridine,8 it
can be prepared by the action of a diazonium salt of
m-bromoaniline on pyridine.9 This reaction forms a
mixture of three isomers, substituted in the 2′, 3′, and
(7) Armit, P. W.; Sime, W. J .; Stephenson, T. A. J . Chem. Soc.,
Dalton Trans.1976, 2121.
(8) de Geest, D. J .; Steel, P. J . Inorg. Chem. Commun. 1998, 1, 358.

2818 Organometallics, Vol. 18, No. 15, 1999
Clark et al.
Ta ble 7. Selected Bon d Dista n ces (Å) a n d An gles
(d eg) for Com p lex 6c
solution was purified by chromatography on a short silica
column (3 cm × 10 cm), using dichloromethane as eluant. The
yellow band was collected. Ethanol was added to the solution
and the volume reduced until crystallization occurred. Bright
yellow microcrystals of pure 1a were collected by filtration (380
mg, 86%). Anal. Calcd for C48H38ClNOP2Ru‚1/4CH2Cl2: C,
Interatomic Distances
Os-C(7)
Os-C(1)
Os-N(1)
Os-N(2)
1.845(5)
2.044(5)
2.173(4)
2.174(4)
Os-P
Os-Cl
Br-C(4)
2.3241(13)
2.5169(13)
1.910(6)
1
67.03; H, 4.49; N, 1.62. Found: C, 67.21; H, 4.78; N, 1.97. H
3
NMR (CDCl3): δ 7.05-7.30 (m, 31H, ArH), 7.33 (d, J HH
)
Interatomic Angles
7.56 Hz, 1H, H3), 6.23 (t apparent, 2H, H4 and H5), 6.77 (d,
C(7)-Os-C(1)
C(7)-Os-N(1)
C(1)-Os-N(1)
C(7)-Os-N(2)
C(1)-Os-N(2)
N(1)-Os-N(2)
C(7)-Os-P
92.4(2)
170.3(2)
N(1)-Os-P
93.10(11)
177.21(12)
96.48(17)
168.97(15)
92.75(12)
86.32(12)
91.80(5)
3J HH ) 7.60 Hz, 1H, H6), 7.42 (d, J HH ) 8.00 Hz, 1H, H3′),
3
N(2)-Os-P
C(7)-Os-Cl
C(1)-Os-Cl
N(1)-Os-Cl
N(2)-Os-Cl
P-Os-Cl
3
6.61 (t apparent, 1H, H5′), 8.54 (d, J HH ) 5.56 Hz, 1H, H6′)
78.12(19)
92.62(19)
86.73(19)
84.95(16)
89.63(15)
94.82(14)
(H denotes phenyl ring, H′ denotes pyridyl ring).
Os(η2-P yP h )Cl(CO)(P P h 3)2 (1b). OsHCl(CO)(PPh3)3 (500
mg) and (PyPh)2Hg (400 mg) were treated as in the prepara-
tion of 1a above. Bright yellow microcrystals of pure 1b were
obtained (390 mg, 87%). Anal. Calcd for C48H38ClNOOsP2: C,
C(1)-Os-P
1
61.83; H, 4.11; N, 1.50. Found: C, 61.28; H, 4.05; N, 1.57. H
3
4′ positions of pyridine, which have to be separated by
chromatography. The transition metal-mediated bro-
mination described above, in which only one isomer is
produced, suggests a potentially useful new methodol-
ogy for the preparation of selectively substituted aro-
matic molecules.
Con clu sion . The 2-(2′-pyridyl)phenyl ligand coordi-
nates strongly to ruthenium or osmium in the complexes
M(η2-PyPh)Cl(CO)(PPh3)2 (1a , 1b) by forming a five-
membered chelate ring. The transition metal-carbon-
(phenyl) bonds in these complexes are relatively resis-
tant to attack by electrophiles, and this enables
electrophilic aromatic substitution reactions to be car-
ried out effectively on the coordinated phenyl ring. The
special activating/directing effects of the metal center
enable derivatives with very unusual substitution pat-
terns on the phenyl ring to be prepared. Finally, it is
demonstrated that [PyrH][Br3] has potential as a re-
agent for effecting the replacement of ligated triph-
enylphosphine by ligated pyridine.
NMR (CDCl3): δ 7.05-7.36 (m, 30H, ArH), 7.31 (d, J HH
)
7.76 Hz, 1H, H3), 6.25 (t apparent, 1H, H4), 6.57 (t apparent,
1H, H5), 6.84 (d, J HH ) 7.64 Hz, 1H, H6), 7.20 (m, 1H, H3′),
7.41 (t apparent, 1H, H4′), 6.17 (t apparent, 1H, H5′), 8.37 (d,
3
3J HH ) 8.37 Hz, 1H, H6′).
Ru (η2-P yP h )I(CO)(P P h 3)2 (2a ). To a solution of 1a (100
mg) in dichloromethane (10 mL) was added AgSbF6 (50 mg)
dissolved in water (5 mL). Ethanol (5 mL) was added, and the
solution was stirred for 10 min, after which time a large excess
of NaI (0.5 g) in water (20 mL) was added. After a further 10
min of stirring, the organic phase was separated and filtered
through paper. Ethanol was added to the filtrate, and the
volume was reduced in vacuo until crystallization occurred.
Bright yellow microcrystals of pure 2a were collected by
filtration (95 mg, 86%). Anal. Calcd for C48H38INOP2Ru‚2/3CH2-
Cl2: C, 58.96; H, 4.00; N, 1.41. Found: C, 58.69; H, 3.87; N,
1.81.1H NMR (CDCl3): δ 7.00-7.35 (m, 32H, ArH), 7.44 (d,
3J HH ) 8.09 Hz, 1H, H3), 6.26 (t apparent, 1H, H4), 6.64 (t
3
apparent, 1H, H5), 6.85 (d, J HH ) 7.56 Hz, 1H, H6), 6.16 (t
3
apparent, 1H, H5′), 8.77 (d, J HH ) 5.78 Hz, 1H, H6′).
Os(η2-P yP h )I(CO)(P P h 3)2 (2b). 1b (100 mg) was treated
as in the preparation of 2a above. Bright yellow microcrystals
of pure 2b were obtained (80 mg, 73%). Anal. Calcd for C48H38
-
INOOsP2: C, 56.31; H, 3.74; N, 1.37. Found: C, 56.54; H, 3.69;
N, 1.51. 1H NMR (CDCl3): δ 6.99-7.31 (m, 32H, ArH), 7.43
(d, 3J HH ) 8.08 Hz, 1H, H3), 6.25 (t apparent, 1H, H4), 6.59 (t
Exp er im en ta l Section
Gen er a l Con sid er a tion s. The general experimental and
spectroscopic techniques employed in this work were the same
as those described previously.10 Mass spectra were recorded
on a Varian VG 70-SE. IR spectra were recorded on a Perkin-
Elmer 1000 FTIR spectrometer. NMR spectra were recorded
on a Bruker DRX 400 spectrometer at 25 °C in CDCl3 using
2D COSY, where appropriate to clarify proton assignments.
Chemical shifts were referenced to Me4Si (δ 0.00). Splitting
patterns and line shapes are indicated as follows: s ) singlet,
d ) doublet, t ) triplet. RuHCl(CO)(PPh3)3,11 OsHCl(CO)-
(PPh3)3,12 and (PyPh)2Hg13 were prepared by literature meth-
ods.
Ru (η2-P yP h )Cl(CO)(P P h 3)2 (1a ). RuHCl(CO)(PPh3)3 (500
mg) and (PyPh)2Hg (450 mg) were combined in freeze-thaw-
degassed toluene (20 mL) under a nitrogen atmosphere and
heated under reflux for 6 h. The toluene was removed in vacuo,
and the resulting paste dissolved in a small amount of
dichloromethane. A few drops of dilute HCl were added, to
decompose any residual mercury reagent. The HCl was
removed by washing with water, and the dichloromethane
3
apparent, 1H, H5), 6.90 (d, J HH ) 7.64 Hz, 1H, H6), 6.07 (t
3
apparent, 1H, H5′), 8.65 (d, J HH ) 5.60 Hz, 1H, H6′).
[Ru (η2-P yP h )(CO)2(P P h 3)2][SbF 6] (3a ). To a solution of
1a (100 mg) in dichloromethane (10 mL) was added AgSbF6
(50 mg) dissolved in water (5 mL). Ethanol (5 mL) was added,
and CO gas was slowly passed through the solution until it
became colorless. The solution was washed with water, the
organic phase separated and filtered through paper. Ethanol
was added to the filtrate, and the volume was reduced in
vacuo. The colorless crystals of 3a that formed were collected
by filtration (105 mg, 83%). MS, m/z: 836 (MI - SbF6), 808
(MI - SbF6 - CO). Anal. Calcd for C49H38F6NO2P2RuSb‚
1/2CH2Cl2: C, 53.37; H, 3.53; N, 1.26. Found: C, 53.59; H, 3.74;
N, 1.50. 1H NMR (CDCl3): δ 6.98-7.37 (m, 31H, ArH), 7.44
3
(d, J HH ) 7.28 Hz, 1H, H3), 6.73 (t apparent, 1H, H5), 6.91
(d, 3J HH ) 7.48 Hz, 1H, H6), 7.06 (d, 3J HH ) 7.16 Hz, 1H, H3′),
7.51 (t apparent, 1H, H4′), 6.71 (t apparent, 1H, H5′), 7.87 (d,
3J HH ) 5.56 Hz, 1H, H6′).
[Os(η2-P yP h )(CO)2(P P h 3)2][SbF 6] (3b). 1b (100 mg) was
treated as in the preparation of 3a above. Colorless crystals
of pure 3b were obtained (110 mg, 88%). MS, m/z: 926 (MI -
SbF6), 898 (MI - SbF6 - CO). Anal. Calcd for C49H38F6NO2-
OsP2Sb: C, 50.70; H, 3.30; N, 1.21. Found: C, 50.81; H, 3.29;
N, 130.1H NMR (CDCl3): δ 6.99-7.36 (m, 31H, ArH), 7.48 (d,
3J HH ) 7.68 Hz, 1H, H3), 6.69 (t apparent, 1H, H5), 6.89 (d,
(9) (a) CIBA Ltd., Neth. Appl. 6414307, 1965; Chem. Abstr. 1966,
64, 713g. (b) Plummer, E. L. J . Agric. Food Chem. 1983, 31, 718.
(10) Maddock, S. M.; Rickard, C. E. F.; Roper, W. R.; Wright, L. J .
Organometallics 1996, 15, 1793.
(11) Ahmad, N.; Levison, J . J .; Robinson, S. D.; Uttley, M. F. Inorg.
Synth. 1974, 15, 45.
(12) Vaska, L. J . Am. Chem. Soc. 1964, 86, 1943.
(13) (a) Constable, E. C.; Leese, T. A. J . Organomet. Chem. 1987,
335, 293. (b) Black, D. St. C.; Deacon, G. B.; Edwards, G. L.; Gatehouse,
B. M. Aust. J . Chem. 1993, 46, 1323.
3
3J HH ) 6.94 Hz, 1H, H6), 7.41 (d, J HH ) 8.20 Hz, 1H, H3′),
7.57 (t apparent, 1H, H4′), 6.62 (t apparent, 1H, H5′), 7.80 (d,
3J HH ) 5.60 Hz, 1H, H6′).

Chelated PyPh Ligand Bound to Ru(II) or Os(II)
Organometallics, Vol. 18, No. 15, 1999 2819
Ru (η2-P yP h )(η2-S2CNMe2)(CO)(P P h 3) (4a ). To a solution
of 1a (100 mg) in dichloromethane (10 mL) was added AgSbF6
(50 mg) dissolved in water (5 mL). Ethanol (5 mL) was added,
and the solution was stirred for 10 min. After this time water
(50 mL) was added and the organic phase separated and
filtered through paper. To the filtrate was added a solution of
NaS2CNMe2 (50 mg) dissolved in a mixture of water (5 mL)
and ethanol (5 mL). The solution was stirred for a further 10
min, the organic phase washed with water, separated, and
filtered through paper. The resulting yellow filtrate was heated
gently for several minutes, then ethanol was added. Reduction
of the solvent volume in vacuo gave yellow microcrystals of
pure 4a (60 mg, 76%). Anal. Calcd for C33H29N2OPRuS2: C,
solution was allowed to stir for 10 min at room temperature.
1a (50 mg) was added, followed after 5 min by sodium acetate
(200 mg) in water (10 mL). The resulting mixture was stirred
until the solid product had coagulated. This was then removed
by filtration and then dissolved in dichloromethane. The
resulting solution was then purified by chromatography on a
20 cm × 3 cm column of silica gel using dichloromethane as
eluant. The light orange band was collected, heptane added,
and the volume reduced in vacuo to obtain pure 5a as a yellow
powder (5 mg, 10%). Anal. Calcd for C48H37ClN2O3OsP2‚1/3CH2-
Cl2: C, 57.72; H, 3.77; N, 2.79. Found: C, 57.62; H, 3.86; N,
2.75. 1H NMR (CDCl3): δ 7.00-7.32 (m, 30H, ArH), 8.16 (s,
3
1H, H3), 7.63 (d, J HH ) 7.81 Hz, 1H, H5), 7.00 (m, 1H, H6),
1
3
59.53; H, 4.39; N, 4.21. Found: C, 59.25; H, 4.22; N, 4.25. H
7.42 (d, J HH ) 7.71 Hz, 1H, H3′), 7.20 (m, 1H, H4′), 6.35 (t
3
NMR (CDCl3): δ 7.10-7.23 (m, 15H, ArH), 7.84 (m, 1H, H3),
6.82 (t apparent, 2H, H4 and H5), 7.53 (m, 1H, H6), 7.60 (d,
3J HH ) 8.12 Hz, 1H, H3′), 7.48 (t apparent, 1H, H4′), 6.64 (t
apparent, 1H, H5′), 8.40 (d, J HH ) 4.90 Hz, 1H, H6′).
Ru (η2-P yP h -4-Br )Cl(CO)(P P h 3)2 (6a ). 1a (200 mg) was
dissolved in dichloromethane (50 mL), to which was added 1
equiv of [PyrH][Br3] (76 mg) in methanol (5 mL). A catalytic
quantity of iron powder (1 mg) was added, and the mixture
stirred for 1 h. The solution was washed with water, and a
solution of AgSbF6 (100 mg) in water (10 mL) was added,
followed by ethanol (10 mL). After stirring for 10 min, NaCl
(1.0 g) in water (50 mL) was added, and the mixture stirred
for a further 10 min. The organic layer was separated and
filtered through paper, then concentrated by reduction of the
solvent volume in vacuo. The resulting solution was then
purified by chromatography on a short silica column (10 cm
× 3 cm) using dichloromethane as the eluant. The first yellow
band was collected. Heptane was added and the volume
reduced in vacuo. The resulting yellow crystals of 6a were
3
apparent, 1H, H5′), 8.57 (d, J HH ) 5.32 Hz, 1H, H6′), 3.33 (s,
3H, NMe), 3.12 (s, 3H, NMe).
Os(η2-P yP h )(η2-S2CNMe2)(CO)(P P h 3) (4b). 1b (100 mg)
was treated as in the preparation of 4a above. Since loss of
the phosphine ligand was less facile, the final yellow dichlo-
romethane solution was heated under reflux for 10 min, then
ethanol was added. Reduction of volume in vacuo gave yellow
microcrystals of pure 4b (65 mg, 80%). Anal. Calcd for
C
33H29N2OOsPS2: C, 52.50; H, 3.87; N, 3.71. Found: C, 52.78;
H, 4.06; N, 3.47.1H NMR (CDCl3): δ 7.10-7.23 (m, 15H, ArH),
7.88 (d, 3J HH ) 7.32 Hz 1H, H3), 6.79 (t apparent, 2H, H4 and
H5), 7.53 (d, 3J HH ) 7.32 Hz, 1H, H6), 7.63 (d, 3J HH ) 8.04 Hz,
1H, H3′), 7.46 (t apparent, 1H, H4′), 6.59 (t apparent, 1H, H5′),
3
8.45 (d, J HH ) 5.40 Hz, 1H, H6′), 3.25 (s, 3H, NMe), 3.02 (s,
3H, NMe).
collected by filtration (150 mg, 69%). Anal. Calcd for C48H37-
BrClNOP2Ru‚1/4CH2Cl2: C, 61.43; H, 4.01; N, 1.48. Found: C,
61.78; H, 3.81; N, 1.57. 1H NMR (CDCl3): δ 7.07-7.32 (m, 31H,
Ru (η2-P yP h -(4,6-(NO2)2)Cl(CO)(P P h 3)2 (5a ). To 1a (100
mg) was added acetic anhydride (2.5 mL) and Cu(NO3)2‚xH2O
(100 mg) in an ice bath. The mixture was stirred for 1 h, during
which time it was slowly allowed to warm to room temperature
and a deep green color developed. A solution of NaOAc (500
mg) in water (20 mL) was added, and the solution was stirred
until the product coagulated. The solution was filtered, and
the resulting sticky oil that was collected was dissolved in
dichloromethane and purified by chromatography on a short
(10 cm × 3 cm) column of silica gel using dichloromethane as
eluant. The first bright yellow band was collected, and crystals
of pure 5a were obtained by adding ethanol and reducing the
volume in vacuo (20 mg, 18%). Anal. Calcd for C48H36ClN3O5P2-
Ru‚2CH2Cl2: C, 54.44; H, 3.65; N, 3.81. Found: C, 54.69; H,
3
ArH), 7.45 (d, J HH ) 2.12 Hz, 1H, H3), 6.28 (dd, J HH ) 8.28,
3
2.12 Hz, 1H, H5), 6.52 (d, J HH ) 8.28 Hz, 1H, H6), 7.39 (d,
3J HH ) 7.96 Hz, 1H, H3′), 6.32 (t apparent, 1H, H5′), 8.62 (d,
3J HH ) 5.24 Hz, 1H, H6′).
Os(η2-P yP h -4-Br )Cl(CO)(P P h 3)2 (6b). 1b (200 mg) was
treated as in the preparation of 6a above, using 1 equiv of
[PyrH][Br3] (69 mg). The first yellow band from the column
was collected. Heptane was added and the volume reduced in
vacuo until pure 6b crystallized as a yellow solid (170 mg,
78%). Anal. Calcd for C48H37BrClNOOsP2‚1/4CH2Cl2: C, 56.13;
1
H, 3.66; N, 1.36. Found: C, 56.29; H, 3.67; N, 1.56. H NMR
3
(CDCl3): δ 7.07-7.30 (m, 31H, ArH), 7.43 (d, J HH ) 2.08 Hz,
3
1H, H3), 6.30 (dd, J HH ) 8.28, 2.08 Hz, 1H, H5), 6.61 (d, J HH
1
3
3.74; N, 3.88. H NMR (CDCl3): δ 7.07-7.25 (m, 30H, ArH),
) 8.28 Hz, 1H, H6), 7.38 (d, J HH ) 7.96 Hz, 1H, H3′), 6.25 (t
3
3
3
7.63 (d, J HH ) 2.12 Hz, 1H, H3), 8.22 (d, J HH ) 2.24 Hz, 1H,
apparent, 1H, H5′), 8.44 (d, J HH ) 5.72 Hz, 1H, H6′).
3
Os(η2-P yP h -4-Br )Cl(CO)(P yr )(P P h 3) (6c). 1b was treated
as in the preparation of 6b above except that 2 equiv of [PyrH]-
[Br3] (138 mg) was used and the mixture was stirred for 16 h.
The product was worked up as described above. Upon purifica-
tion by column chromatography, a small amount of 6b eluted
first, followed by a darker band. This darker band was
collected, heptane added, and the solvent volume reduced in
vacuo to give pure 6c as a yellow solid (55 mg, 31%). Anal.
Calcd for C35H27BrClN2OOsP‚1/2C7H16: C, 52.71; H, 3.91; N,
H5), 7.72 (d, J HH ) 7.68 Hz, 1H, H3′), 7.57 (t apparent, 1H,
H4′), 6.49 (t apparent, 1H, H5′), 8.50 (d, J HH ) 5.08 Hz, 1H,
3
H6′).
Os(η2-P yP h -(4,6-(NO2)2)Cl(CO)(P P h 3)2 (5b). To 1a (100
mg) was added acetic anhydride (5 mL) and Cu(NO3)2‚xH2O
(150 mg). The mixture was stirred for 1 h, during which time
a deep green color developed. A solution of NaOAc (500 mg)
in water (20 mL) was added, and the solution was stirred until
the product coagulated. The solution was filtered, and the
resulting sticky oil that was collected was dissolved in dichlo-
romethane and purified by chromatography on a short (10 cm
× 3 cm) column of silica gel using dichloromethane as eluant.
The light orange band eluting first was collected. Light orange
microcrystals of pure 5b were obtained by adding hexane and
reducing the volume in vacuo (40 mg, 36%). Anal. Calcd for
1
3.19. Found: C, 52.68; H, 3.87; N, 2.91. H NMR (CDCl3): δ
7.11-7.39 (m, 16H, ArH), 6.77 (m, 1H, H5), 7.30 (m, 1H, H6),
7.20 (m, 1H, H3′), 7.57 (t apparent, 1H, H4′), 6.79 (t apparent,
3
3
1H, H5′), 9.05 (d, J HH ) 5.68 Hz, 1H, H6′), 7.53 (d, J HH
)
6.08 Hz, 2H, H2′′), 7.00 (t apparent, 2H, H3′′), 8.56 (m, 1H,
H4′′).
Os(η2-P yP h -4-CO2H)Cl(CO)(P P h 3)2 (7a ). 6b (100 mg) was
dissolved in dry, deoxygenated tetrahydrofuran (20 mL) under
an atmosphere of nitrogen and cooled to 0 °C. BuLi in hexanes
(2 equiv, 0.116 mL 1.7 mol L-1) was added dropwise, and the
mixture stirred for 10 min. A stream of CO2 was passed
through the solution for several minutes, after which time the
solvent was removed entirely in vacuo. The resulting paste
was dissolved in ethanol (10 mL) and water (2 mL) and a small
C
30H21ClN3O5OsP‚CH2Cl2: C, 53.15; H, 3.46; N, 3.79. Found:
1
C, 52.88; H, 3.43; N, 3.67. H NMR (CDCl3): δ 7.08-7.32 (m,
3
3
30H, ArH), 7.60 (d, J HH ) 2.32 Hz, 1H, H3), 8.29 (d, J HH
)
3
2.28 Hz, 1H, H5), 7.72 (d, J HH ) 8.04 Hz, 1H, H3′), 7.51 (t
apparent, 1H, H4′), 6.42 (t apparent, 1H, H5′), 8.35 (d, 3J HH
5.44 Hz, 1H, H6′).
)
Os(η2-P yP h -4-NO2)Cl(CO)(P P h 3)2 (5c). Acetic anhydride
(2.5 mL) was added to Cu(NO3)2‚xH2O (50 mg), and the

2820 Organometallics, Vol. 18, No. 15, 1999
Clark et al.
3
pellet of NaOH added. The resulting solution was filtered, and
several drops of diluted HCl added to the filtrate until it was
slightly acidic. The solvent volume was reduced in vacuo, to
give a yellow solid, which was isolated by filtration. The solid
was recrystallized from dichloromethane, ethanol, and water
to give pure 7a (25 mg, 26%). MS, m/z: 977 (MI), 942 (MI -
Cl). Anal. Calcd for C49H38ClNO3OsP2.2/3CH2Cl2: C, 57.75; H,
3.84; N, 1.36. Found: C, 57.71; H, 4.36; N, 1.35. 1H NMR
(CDCl3): δ 7.09-7.27 (m, 31H, ArH), 8.04 (s, 1H, H3), 6.88
H5′), 8.69 (d, J HH ) 4.72 Hz, 1H, H6′) ppm. 13C NMR: δ,
155.78, 141.25, 123.04 (C1, C3, C2′); 149.68, 137.01, 131.89,
130.25, 130.02, 125.41, 122.69, 120.65 ppm (C2, C4-6, C3′-6′)
(C denotes phenyl ring, C′ denotes pyridyl ring).
X-r a y Cr ysta llogr a p h y. The crystal data, data collection,
and refinement parameters for the five structures are listed
in Table 2.
All measurements were made on a Siemens SMART dif-
fractometer using graphite-monochromated Mo KR radiation,
λ ) 0.71073 Å. Data collection covered a nominal sphere
(hemisphere for monoclinic) of reciprocal space by a series of
four (three) sets of exposures each covering 0.3° in ω. Crystal
decay was monitored by repeating the initial frames at the
end of the data collection and analyzing duplicate reflections.
Unit cell parameters were obtained by least-squares fit to all
data with I > 10σ(I). Lorentz and polarization corrections were
applied and absorption corrections by analyzing equivalent
reflections.14
The structures were solved by Patterson and difference
Fourier methods using SHELXS-9715 and refined on F2 using
all data by full-matrix least squares with the program SHELXL-
97.16 All non-hydrogen atoms were refined with anisotropic
thermal parameters. Hydrogen atoms were included in cal-
culated positions with thermal parameter 20% greater than
the carrier atom. In 3b there is a half molecule of dichlo-
romethane solvent, and in 6c there is a molecule of chloroform.
3
3
(d, J HH ) 8.00 Hz, 1H, H5), 7.02 (d, J HH ) 8.12 Hz, 1H, H6)
3
7.60 (d, J HH ) 7.96 Hz, 1H, H3′), 6.27 (t apparent, 1H, H5′),
3
8.40 (d, J HH ) 4.28 Hz, 1H, H6′), CO2H not located.
Os(η2-P yP h -4-Sn Bu 3)Cl(CO)(P P h 3)2 (7b). 6b (200 mg)
was dissolved in dry, deoxygenated tetrahydrofuran (30 mL)
under an atmosphere of nitrogen and cooled to 0 °C. BuLi in
hexanes (2 equiv, 0.232 mL, 1.7 mol L-1) was added dropwise,
and the mixture stirred for 10 min. An excess of Bu3SnCl (0.4
mL) was added, and the mixture stirred for 10 min, after which
time the solvent was removed in vacuo. The resulting paste
was dissolved in dichloromethane and filtered through paper.
Ethanol was added to the filtrate and the solvent volume
reduced in vacuo, to give pure 7b as a waxy yellow solid (110
mg, 46%). Anal. Calcd for C60H64ClNOOsP2Sn‚1/3CH2Cl2: C,
1
57.98; H, 5.22; N, 1.12. Found: C, 58.04; H, 5.29; N, 1.57. H
NMR (CDCl3): δ 7.04-7.30 (m, 31H, ArH), 7.34 (m, 1H, H3),
3
6.24 (m, 1H, H5), 6.70 (d, J HH ) 7.44 Hz, 1H, H6) 7.42 (d,
3J HH ) 8.04 Hz, 1H, H3′), 6.19 (t apparent, 1H, H5′), 8.41 (d,
3J HH ) 5.28 Hz, 1H, H6′), 0.99 (m, 6H, CH2), 1.36 (m, 6H, CH2),
1.55 (m, 6H, CH2), 0.93 (t apparent, 9H, CH3).
Ack n ow led gm en t. We thank the Marsden fund,
administered by The Royal Society of New Zealand, for
supporting this work and for granting a Ph.D. scholar-
ship to A.M.C. We also thank A. G. Oliver for assistance
with the crystallography.
2′-(3-Br om op h en yl)p yr id in e (8). 6a (100 mg) was dis-
solved in toluene (20 mL), and concentrated HCl (1 mL) was
added. The solution was heated under reflux while exposed
to air, for 16 h, after which time water (50 mL) was added
and the aqueous layer separated. To this solution was then
added NaOH (5.0 g) dissolved in water (100 mL). The cloudy
solution was then stirred with dichloromethane (50 mL) and
ethanol (1 mL) for 1 h, after which time the cloudiness had
disappeared. The organic layer was separated and filtered
through paper, and the volume reduced in vacuo until only 8,
as a viscous oil, remained (7 mg, 25%). MS, m/z: 233, 235 (MI),
154 (MI - Br); high resolution, 232.98484, 234.98104 (requires
Su p p or tin g In for m a tion Ava ila ble: Tables of crystal
data, collection and refinement parameters, positional and
anisotropic displacement parameters, and bond distances and
angles for 3b, 4b, 5c, 6b, and 6c. This material is available
free of charge via the Internet at http://pubs.acs.org.
OM990232A
1
232.98401, 234.98196). H NMR: δ 8.16 (s, 1H, H2), 7.90 (d,
(14) Blessing, L. H. Acta Crystallogr. Sect. A 1995, 51, 33.
(15) Sheldrick, G. M. Acta Crystallogr. Sect. A 1990, 46, 467.
(16) Sheldrick, G. M. SHELXL97, Program for the Refinement of
Crystal Structures; University of Go¨ttingen: Germany, 1997.
3J HH ) 7.72 Hz, 1H, H4), 7.33 (t apparent, 1H, H5), 7.53 (d,
3
3J HH ) 7.76 Hz, 1H, H6), 7.69 (d, J HH ) 7.92 Hz, 1H, H3′),
7.76 (t apparent, 1H, H4′), 7.26 (dd, 3J HH ) 8.69, 4.72 Hz, 1H,