Tris(N-pyrrolyl)phosphine complexes of osmium(II) and osmium(0)

Article abstract of DOI:10.1016/S0022-328X(01)01383-3

Reaction between OsHC1(CO)(PPh₃)₃ and the powerful π-accepting ligand tris(N-pyrrolyl)phosphine, P(NC₄H₄)₃, results in replacement of the PPh₃ ligand trans to hydride giving decarboxylation of Os(p-tolyl)(η²-O₂CH) (CO)(PPh₃)₂ (2) in the presence of P(NC₄H₄)₃. Complex 3, despite having cis-hydride and p-tolyl ligands, is resistant to reductive elimination of toluene. Osmium(0) complexes containing P(NC₄ H₄)₃ are conveniently prepared by replacement of one PPh₃ ligand from Os(CO)(CE)(PPh₃)₃ (E = O, S) to give Os(CO)(CE)[P(NC₄H₄)₃] (PPh₃)₂ (4, E = O; 5, E = S). Structure determination of 4 confirms a trigonal bipyramidal geometry with the PPh₃ ligands in the axial positions and the π-accepting P(NC₄H₄)₃ ligand in the expected equatorial site.

Full text of DOI:10.1016/S0022-328X(01)01383-3

Journal of Organometallic Chemistry 643–644 (2002) 168–173
www.elsevier.com/locate/jorganchem
Tris(N-pyrrolyl)phosphine complexes of osmium(II) and osmium(0)
Clifton E.F. Rickard, Warren R. Roper *, Scott D. Woodgate, L. James Wright
Department of Chemistry, The Uni6ersity of Auckland, Pri6ate Bag 92019, Auckland, New Zealand
Received 25 June 2001; accepted 10 October 2001
Dedicated to Professor Franc¸ois Mathey on the occasion of his 60th birthday and in recognition of his major contributions to phosphorus
chemistry
Abstract
Reaction between OsHCl(CO)(PPh3)3 and the powerful p-accepting ligand tris(N-pyrrolyl)phosphine, P(NC4H4)3, results in
replacement of the PPh3 ligand trans to hydride giving OsHCl(CO)[P(NC4H4)3](PPh3)2 (1). The analogue of 1 with Cl replaced by
p-tolyl, OsH(p-tolyl)(CO)[P(NC4H4)3](PPh3)2 (3), is accessible by thermal decarboxylation of Os(p-tolyl)(h2-O2CH)(CO)(PPh3)2
(2) in the presence of P(NC4H4)3. Complex 3, despite having cis-hydride and p-tolyl ligands, is resistant to reductive elimination
of toluene. Osmium(0) complexes containing P(NC4H4)3 are conveniently prepared by replacement of one PPh3 ligand from
Os(CO)(CE)(PPh3)3 (E=O, S) to give Os(CO)(CE)[P(NC4H4)3](PPh3)2 (4, E=O; 5, E=S). Structure determination of 4 confirms
a trigonal bipyramidal geometry with the PPh3 ligands in the axial positions and the p-accepting P(NC4H4)3 ligand in the expected
equatorial site. © 2002 Elsevier Science B.V. All rights reserved.
Keywords: Tris(N-pyrrolyl)phosphine complex; Hydride complex; Osmium; X-ray crystal structure
1. Introduction
and, we describe in this paper the preparation and
spectroscopic study of tris(N-pyrrolyl)phosphine com-
plexes of osmium(II) and osmium(0). In addition, a
Amongst PR3 ligands, tris(N-pyrrolyl)phosphine has
been shown to have strong p-accepting properties but
to be a rather weak s-donor [1]. This is because the
N-pyrrolyl substituents are unusually effective electron-
withdrawing groups as a result of aromatic delocalisa-
tion of the nitrogen lone pair into the pyrrole ring.
N-pyrrolyl substituents when present on silyl ligands
also exhibit the same electron-withdrawing properties
and these effects have been studied both experimentally
[2] and theoretically [3]. IR studies of w(CO) for
rhodium compounds containing both CO and
P(NC4H4)3 show the poor s-donor and good p-accep-
tor properties of P(NC4H4)3. Further evidence for the
exceptional p-accepting properties is provided by the
remarkable observation of complete substitution of CO
in the electron-rich anion [Rh(CO)4]− to give
[Rh{P(NC4H4)3}4]− [1a]. To further consolidate this
bonding picture of the tris(N-pyrrolyl)phosphine lig-
structural
study
of
an
osmium(0)
tris(N-
pyrrolyl)phosphine complex has been completed.
2. Results and discussion
2.1. Introduction of tris(N-pyrrolyl)phosphine to
OsHCl(CO)(PPh3)3
OsHCl(CO)(PPh3)3 has a labile phosphine ligand lo-
cated trans to the hydride ligand. We have shown
previously that a number of complexes of the type
OsHCl(CO)(PR3)(PPh3)2 are easily accessible from the
reaction between the appropriate phosphine and OsH-
Cl(CO)(PPh3)3 [4]. Following this approach, treatment
of OsHCl(CO)(PPh3)3 with one equivalent of tris(N-
pyrrolyl)phosphine
gave
OsHCl(CO)[P(NC4H4)3]-
(PPh3)2 (1) as a colourless product (see Scheme 1). The
IR spectrum of 1 shows w(OsH) at 2035 cm−1, w(CO)
at 1936 cm−1 and a strong band at 1178 cm−1 associ-
ated with the tris(N-pyrrolyl)phosphine ligand. The
* Corresponding authors. Tel.: +64-9-373-7999x8320; fax: +64-9-
373-7422.
E-mail address: w.roper@auckland.ac.nz (W.R. Roper).
0022-328X/02/$ - see front matter © 2002 Elsevier Science B.V. All rights reserved.
PII: S0022-328X(01)01383-3

C.E.F. Rickard et al. / Journal of Organometallic Chemistry 643–644 (2002) 168–173
169
2.2. An osmium(II) complex containing hydride, p-tolyl
and tris(N-pyrrolyl)phosphine ligands
We have previously demonstrated that thermal de-
carboxylation of Os(Aryl)(h2-O2CH)(CO)(PPh3)2 in the
presence of excess triphenylphosphine produces Os-
Scheme 1. Synthesis of an hydrido, tris(N-pyrrolyl)phosphine com-
plex of osmium(II).
H(Aryl)(CO)(PPh3)3
[5].
When
Os(p-tolyl)(h2-
O2CH)(CO)(PPh3)2 (2) is heated in the presence of
tris(N-pyrrolyl)phosphine, decarboxylation occurs and
OsH(p-tolyl)(CO)[P(NC4H4)3](PPh3)2 (3) is formed as a
colourless solid in good yield (see Scheme 2). In the IR
spectrum of 3, w(OsH) appears at 2137 cm−1 and
w(CO) at 1935, 27 cm−1 higher than that observed for
OsH(p-tolyl)(CO)(PPh)3 [5b].
observed w(CO) for 1 is 25 cm−1 higher than that
observed for OsHCl(CO)(PPh3)3. This indicates a sig-
nificantly decreased donation of electron density from
the osmium to the carbonyl ligand as a result of the
increased p-acceptor and reduced s-donor character of
the tris(N-pyrrolyl)phosphine ligand relative to
triphenylphosphine.
1
The H-NMR spectrum of complex 3 reveals a dou-
blet of triplets for the hydride resonance at −6.44
2
ppm, with coupling constants of JHPtrans=129.6 Hz
NMR studies confirmed the geometrical arrangement
of the phosphine ligands as depicted in Scheme 1. In
and 2JHPcis=28.8 Hz. These signals collapse to a singlet
1
in the H{31P}-NMR spectrum. The coupling pattern is
1
the H-NMR spectrum of 1, the pyrrolyl protons are
consistent with the tris(N-pyrrolyl)phosphine ligand be-
ing trans to the hydride and the two mutually trans
triphenylphosphine ligands cis to the hydride, as de-
picted in Scheme 2.
visible as multiplet resonances at 6.04 and 6.13 ppm.
These chemical shifts are at slightly higher field values
than those recorded for free tris(N-pyrrolyl)phosphine
(6.43 and 6.88 ppm). A doublet of triplets at −4.92
ppm is assigned to the hydride ligand, and this col-
The 13C-NMR spectrum of complex 3 shows a reso-
nance at 23.0 ppm assigned to the methyl group and
doublet resonances at 111.35 (3JCP=5.0 Hz) and 123.50
ppm (2JCP=6.0 Hz) assigned to the pyrrolyl ring car-
bons. The 31P-NMR spectrum reveals a doublet reso-
nance at −2.55 ppm (2JPP=13.2 Hz), which is
assigned to the two triphenylphosphine phosphorus
atoms, and a triplet at 78.08 ppm (2JPP=13.6 Hz)
assigned to the single tris(N-pyrrolyl)phosphine phos-
phorus atom. Complex 3 exhibits remarkable thermal
stability and when heated under reflux in benzene for 2
h with an excess of triphenylphosphine, there is no
replacement of the tris(N-pyrrolyl)phosphine ligand by
triphenylphosphine, nor is any reductive elimination of
toluene observed. However, CO is effective in replacing
the tris(N-pyrrolyl)phosphine ligand and when 3 is
treated with CO (4 atm for 30 min), OsH(p-
tolyl)(CO)2(PPh3)2 [5b] is formed in high yield.
1
lapses to a singlet in the H{31P}-NMR spectrum. The
splitting pattern of the hydride signal indicates the
geometrical arrangement of the ligands about the os-
mium atom. The doublet coupling constant of 138.4 Hz
is consistent with coupling to a single trans phosphine
ligand, while the smaller triplet coupling constant (25.2
Hz) indicates cis coupling of the hydride to two equiva-
lent, mutually trans, triphenylphosphine ligands. This
fixes the geometry as depicted in Scheme 1.
The 13C-NMR spectrum of 1 shows two resonances
for the tris(N-pyrrolyl)phosphine carbon atoms; a dou-
blet at 111.32 ppm (2JCP=5.0 Hz) and a second dou-
blet at 123.98 ppm (3JCP=5.0 Hz). The 31P-NMR
spectrum shows a triplet at 68.74 ppm with a coupling
2
constant JPP of 13.3 Hz, which is assigned to the
tris(N-pyrrolyl)phosphine phosphorus atom. A second
resonance at 3.71 ppm, which is split into a doublet
2
with JPP=13.4 Hz, is assigned to the triphenylphos-
2.3. Introduction of tris(N-pyrrolyl)phosphine to the
osmium(0) complex, Os(CO)2(PPh3)3
phine phosphorus nuclei. These observations also
confirm the geometry depicted in Scheme 1.
Os(CO)2(PPh3)3 [6] has a labile triphenylphosphine
ligand that can be replaced by many h1- and h2-ligands
[7]. Accordingly, when a benzene solution containing
tris(N-pyrrolyl)phosphine and Os(CO)2(PPh3)3 is sub-
jected to photolysis from a 1000 W tungsten–halogen
lamp, Os(CO)2[P(NC4H4)3](PPh3)2 (4) is formed (see
Scheme 3). While Os(CO)2(PPh3)3 is a highly air-sensi-
tive complex, 4 could be purified by column chro-
matography in the air. The IR spectrum of 4 shows
h(CO) at 1922 and 1867 cm−1 indicating that the
Scheme 2. Synthesis of an hydrido, p-tolyl, tris(N-pyrrolyl)phosphine
complex of osmium(II).
1
two-carbonyl ligands are mutually cis. The H-NMR

170
C.E.F. Rickard et al. / Journal of Organometallic Chemistry 643–644 (2002) 168–173
rus resonance of the triphenylphosphine ligands at 9.43
(2JPP=30.0 Hz) and a triplet for the P(NC4H4)3 phos-
phorus at 83.64 ppm (2JPP=31.0 Hz). This is consistent
with the complex having a trigonal bipyramidal geome-
try with axial triphenylphosphine ligands and an equa-
torial tris(N-pyrrolyl)phosphine ligand, as depicted in
Scheme 3. This geometry was confirmed by an X-ray
crystal structure determination.
Scheme 3. Synthesis of tris(N-pyrrolyl)phosphine complexes of os-
mium(0).
2.4. Crystal structure of Os(CO)2[P(NC4H4)3](PPh3)2
(4)
The molecular geometry of 4 is shown in Fig. 1 and
selected bond lengths and angles are presented in Ta-
bles 1 and 2. The geometry about osmium can be
described as distorted trigonal bipyramidal with the
triphenylphosphine ligands axial [P(2)ꢀOs(1)ꢀP(3),
160.66(6)°] and the two carbonyl ligands equatorial
[C(1)ꢀOs(1)ꢀC(2), 133.2(3)°]. The osmiumꢀtriphenyl-
phosphine distances and the osmiumꢀcarbonyl dis-
tances are normal. The tris(N-pyrrolyl)phosphine lig-
and occupies an equatorial position of the trigonal
bipyramidal structure, where maximum overlap with
metal p-donor orbitals is possible. The osmiumꢀtris(N-
,
pyrrolyl)phosphine distance [Os(1)ꢀP(1), 2.2764(18) A]
Fig. 1. Molecular geometry of Os(CO)2[P(NC4H4)3](PPh3)2 (4).
is significantly shorter than that observed for the os-
miumꢀtriphenylphosphine bonds [Os(1)ꢀP(2), 2.392(2)
Table 1
Data collection and processing parameters for 4
,
,
A; Os(1)ꢀP(3), 2.370(2) A]. A search of the Cambridge
crystallographic database reveals that the osmiumꢀ
tris(N-pyrrolyl)phosphine distance in complex 4 is right
at the short end of the range of observed OsꢀPR3
Formula
C50H42N3O2OsP3
Molecular weight
Temperature (K)
999.98
173
,
Wavelength (A)
0.71069
Monoclinic
P21/c
Crystal system
Space group
Table 2
,
Selected bond lengths (A) and angles (°) for 4
,
a (A)
19.177(6)
12.429(8)
18.467(7)
103.10(3)
4287(3)
,
b (A)
Bond lengths
Os(1)ꢀC(1)
Os(1)ꢀC(2)
Os(1)ꢀP(1)
Os(1)ꢀP(3)
Os(1)ꢀP(2)
P(1)ꢀN(31)
P(1)ꢀN(11)
P(1)ꢀN(21)
C(1)ꢀO(1)
C(2)ꢀO(2)
,
c (A)
i (°)
V (A )
1.898(6)
1.911(7)
2.2764(18)
2.370(2)
2.392(2)
1.719(5)
1.727(5)
1.744(5)
1.156(7)
1.135(8)
3
,
Z
4
Dcalc (g cm−3
F(000)
)
1.549
2000
3.13
v (mm−1
)
Crystal size (mm)
A (min–max)
2q (min–max) (°)
0.47×0.37×0.35
0.321 0.407
1–25
Independent reflections
Function minimised
Observed reflections
Goodness of fit on F2
R, wR2 (observed data) a
R, wR2 (all data)
7772
Bond angles
Sw(Fo2−Fc2)2
5863
C(1)ꢀOs(1)ꢀC(2)
C(1)ꢀOs(1)ꢀP(1)
C(2)ꢀOs(1)ꢀP(1)
C(1)ꢀOs(1)ꢀP(3)
C(2)ꢀOs(1)ꢀP(3)
P(1)ꢀOs(1)ꢀP(3)
C(1)ꢀOs(1)ꢀP(2)
C(2)ꢀOs(1)ꢀP(2)
P(1)ꢀOs(1)ꢀP(2)
P(3)ꢀOs(1)ꢀP(2)
O(1)ꢀC(1)ꢀOs(1)
O(2)ꢀC(2)ꢀOs(1)
133.2(3)
113.12(19)
113.7(2)
86.8(2)
84.96(18)
99.81(7)
91.3(2)
82.41(18)
98.66(7)
160.66(6)
177.8(5)
174.5(6)
1.007
0.0368, 0.0877
0.0639, 0.0970
+0.90 −0.93
−3
,
Difference map (min–max) (e A
)
a R=SꢀFoꢀ−ꢀFcꢀꢀ/SꢀFoꢀ; wR2={S[w(Fo2−Fc2)2]/S[w(Fo2)2]}1/2
.
spectrum of 4 shows broad multiplets at 6.00 and 6.22
ppm, which are assigned to the pyrrolyl protons. The
31P-NMR spectrum shows a doublet for the phospho-

C.E.F. Rickard et al. / Journal of Organometallic Chemistry 643–644 (2002) 168–173
171
,
3. Conclusions
distances (the mean of 1450 observations is 2.363 A
with a standard deviation (S.D.) 0.051). The structure
of a closely related complex, Os(CO)2[PH(OMe)Ph]-
(PPh3)2, has been determined [8] and found to have the
same arrangement of ligands about osmium with the
triphenylphosphine ligands axial and the two carbonyl
ligands and PH(OMe)Ph occupying the equatorial posi-
tions. In this complex, the osmiumꢀPH(OMe)Ph bond
length is 2.299(4) A, 0.023 A longer than that of the
corresponding osmiumꢀtris(N-pyrrolyl)phosphine bond
length in complex 4.
The variation of phosphorusꢀnitrogen bond lengths
in compounds with a MꢀPꢀN linkage has been used as
a diagnostic tool to examine the extent of phosphorus
back bonding [1]. In the general case LnMꢀPZ3, as the
MꢀP bond distance decreases because of increased MꢀP
back bonding, the PꢀZ distances are increased. This has
been attributed to back bonding into PꢀZ s* orbitals.
Structural studies of the two rhodium complexes,
RhCl(CO)[P(NC4H4)3]2 and [PPN][Rh(CO){P(NC4-
H4)3}3] [1], show that the PꢀN distances in the anionic
complex, where greater back bonding is to be expected,
Two new tris(N-pyrrolyl)phosphine complexes of os-
mium(II) have been prepared. Both showed IR car-
bonyl stretching absorptions at significantly higher
frequencies than the analogous triphenylphosphine
complexes, reflecting the p-acceptor nature of the
tris(N-pyrrolyl)phosphine ligand. Two new osmium (0)
complexes,
Os(CO)2[P(NC4H4)3](PPh3)2
(4)
and
,
,
Os(CO)(CS)[P(NC4H4)3](PPh3)2 (5) were also prepared
and 4 was studied structurally. In 4, the location of the
tris(N-pyrrolyl)phosphine, the w(CO) values and the
OsꢀP and PꢀN distances all point to the tris(N-
pyrrolyl)phosphine ligand acting as a very good p-ac-
ceptor in this complex.
4. Experimental
4.1. General procedures and instruments
Standard laboratory procedures were followed as
have been described previously [9]. The compound
Os(p-tolyl)Cl(CO)(PPh3)2 [10] was prepared according
to the literature method.
,
were significantly longer (av. 1.735 A) than those found
,
in the neutral species (av. 1.690 A). In complex 4 the
IR spectra (4000–400 cm−1) were recorded as Nujol
mulls between KBr plates on a Perkin–Elmer Paragon
1000 spectrometer. NMR spectra were obtained on a
PꢀN bond distances are long [1.744(5), 1.719(5) and
,
1.727(5) A], consistent with the idea that the tris(N-
pyrrolyl)phosphine ligand is behaving as a p-accepting
ligand in this electron-rich osmium(0) complex. It can
also be noted that the w(CO) bands for 4 at 1922
and 1867 cm−1 are some 20 cm−1 higher than
those observed for Os(CO)2[PH(OMe)Ph](PPh3)2 (1904,
1847 cm−1) [8] again pointing to the excellent p-
accepting properties of the tris(N-pyrrolyl)phosphine
ligand.
1
Bruker DRX 400 at 25 °C. H-, 13C- and 31P-NMR
spectra were obtained operating at 400.1 (1H), 100.6
(13C) and 162.0 (31P) MHz, respectively. Resonances are
quoted in ppm and 1H-NMR spectra referenced to
either Me4Si (0.00 ppm) or the proteo-impurity in the
solvent (7.25 ppm for CHCl3). 13C-NMR spectra were
referenced to CDCl3 (77.00 ppm) and 31P-NMR spectra
to 85% ortho-phosphoric acid (0.00 ppm) as an external
standard. Mass spectra were recorded using the fast
atom bombardment technique with a Varian VG 70-SE
mass spectrometer. Elemental analyses were obtained
from the Microanalytical Laboratory, University of
Otago.
2.5. Introduction of tris(N-pyrrolyl)phosphine to the
osmium(0) complex, Os(CO)(CS)(PPh3)3
Reaction between Os(CO)(CS)(PPh3)3 and P(NC4-
H4)3 again proceeds with displacement of one triphenyl-
phosphine ligand to give Os(CO)(CS)[P(NC4H4)3]-
(PPh3)2 (5) (see Scheme 3). The IR spectrum of complex
4.2. Preparation of OsHCl(CO)[P(NC4H4)3](PPh3)2 (1)
Freshly deoxygenated benzene (20.0 ml) was added
to a Schlenk tube containing OsHCl(CO)(PPh3)3 (200
mg, 0.192 mmol) and P(NC4H4)3 (44.0 mg, 0.19 mmol).
The colourless solution was heated under reflux for 2 h
and cooled. C6H12 (50 ml) was added and the resulting
white flocculent powder was collected by filtration,
washed with C6H12 (20 ml) and recrystallised from
CH2Cl2–EtOH (25:10 ml) to yield white needles of pure
1 (176 mg, 91%). Anal. Calc. for C49H43ClN3OOsP3: C,
58.36; H, 4.30; N, 4.17. Found: C, 58.21; H, 4.47; N,
4.05%. IR (cm−1): 1936 w(CO); 2035 w(OsH); 1178,
1088, 1061, 1040. 1H-NMR (CDCl3; l): −4.92 (dt,
5 reveals w(CO) at 1904 cm−1 and w(CS) at 1247 cm−1
.
The pyrrolyl ring carbon resonances appear as doublets
at 110.86 (2JCP=6.0 Hz) and 123.67 (3JCP=6.0 Hz) in
the 13C-NMR spectrum. The 31P-NMR spectrum shows
a doublet at 8.96 ppm (2JPP=35.6 Hz), which is as-
signed to the two phosphorus nuclei of the equivalent
triphenylphosphine ligands, and a triplet at 83.38 ppm
(2JPP=35.0 Hz), which is assigned to the tris(N-
pyrrolyl)phosphine ligand. This is consistent with a
structure that is the same as that of complex 4 with CS
replacing one CO.

172
C.E.F. Rickard et al. / Journal of Organometallic Chemistry 643–644 (2002) 168–173
2
2
1,3
OsH, JHPtrans=138.4 Hz, JHPcis=25.2 Hz); 6.04 (m,
P(NC4H4)3); 6.13 (m, P(NC4H4)3); 7.00–7.31 (m, 30H,
PPh3). 13C-NMR (C6D6; l): 111.32 (d, P(NC4H4)3,
Hz), 129.31 (s, PPh3 para); 134.41 (PPh3 ipso
J
=
CP
52.3 Hz); 134.41 (t%, PPh3 meta, 3,5JCP=10.1 Hz). 31P-
NMR (CDCl3; l): −2.55 (d, PPh3, 2JPP=13.2 Hz);
2JCP=5.0 Hz); 123.98 (d, P(NC4H4)3, JCP=5.0 Hz);
78.08 (t, P(NC4H4)3, JPP=13.6 Hz).
3
2
127.55 (t% [9], PPh3 ortho, 2,4JCP=10.1 Hz); 129.35 (s,
PPh3 para); 134.37 (t%, PPh3 meta 3,5JCP=10.1 Hz);
133.91 (t%, PPh3 ipso, 1,3JCP=42.3 Hz). 31P-NMR
(CDCl3; l): 3.71 (d, PPh3, 2JPP=13.4 Hz); 68.74 (t,
4.5. Preparation of Os(CO)2[P(NC4H4)3](PPh3)2 (4)
2
P(NC4H4)3, JPP=13.3 Hz).
Freshly distilled and deoxygenated C6H6 (20 ml) was
added to a Schlenk tube containing Os(CO)2(PPh3)3
(200 mg, 0.193 mmol) and P(NC4H4)3 (43.0 mg, 0.193
mmol). The bright yellow solution was then subjected
to photolysis from a 1000 W tungsten–halogen lamp
for a period of 25 min. Throughout the duration of this
experiment the reaction mixture was kept between 30
and 40 °C and the bright yellow colour faded to a
lighter shade of yellow. The volume of C6H6 was then
reduced and C6H12 (50 ml) was added to yield a pale
lemon-yellow solid. This solid was collected by filtra-
tion and either recrystallised from CH2Cl2–EtOH
(25:10 ml) or subjected to column chromatography on
silica gel (5×1.5 cm) using CH2Cl2 as eluant to give
lemon-yellow crystals of pure 4 (172 mg, 89%). m/z
1001.2105; C50H42N3OsO2P3 requires 1001.2123. Anal.
Calc. for C50H42N3OsO2P3: C, 60.05; H, 4.23; N, 4.20.
Found: C, 59.55; H, 4.10; N, 4.35%. IR (cm−1): 1922,
1867 w(CO), 1586, 1175, 1288, 1261, 1175, 1125, 1083,
1056, 1037, 803. 1H-NMR (CDCl3; l): 6.00 (m,
P(NC4H4)3); 6.22 (m, P(NC4H4)3); 7.19–7.42 (m, 30H
PPh3). 13C-NMR (C6D6; l): 110.66 (d, P(NC4H4)3,
4.3. Preparation of Os(p-tolyl)(p2-O2CH)(CO)(PPh3)2
(2)
Os(p-tolyl)Cl(CO)(PPh3)2 (0.500 mg, 0.575 mmol)
was added to CH2Cl2 (80 ml). A solution of HCOONa
(0.200 mg, 2.94 mmol) in EtOH (ca. 60 ml) and water
(ca. 1 ml) was added slowly and the resulting suspen-
sion stirred at room temperature (r.t.) for ca. 1 h.
During this time the red suspension turned into a
yellow solution. The CH2Cl2 was removed under re-
duced pressure without heating and the product col-
lected and washed well with water, EtOH and C6H12.
Recrystallisation from CH2Cl2–EtOH afforded yellow
chunky crystals of pure 2 (0.490 mg, 97%). Anal. Calc.
for C45H38O3OsP2: C, 61.49; H, 4.36; P, 7.05. Found: C,
61.45; H, 4.57; P, 6.91%. IR (cm−1): 1899 w(CO), 1543,
1359 w(CO) formate, 1308, 813, 801. 1H-NMR
(CD2Cl2–d6-DMSO; l): 1.99 (s, CH3); 6.21–6.19 (m,
C6H4CH3); 6.69–6.68 (m, C6H4CH3); 7.38–7.29 (m,
4
PPh3); 7.99 (t, O2CH, JHP=1.6 Hz). Compound 2 is
3
2JCP=6.0 Hz); 123.32 (d, P(NC4H4)3, JCP=6.0 Hz);
too insoluble for measurement of a satisfactory 13C-
NMR spectrum.
127.73 (t%, PPh3 ortho, 2,4JCP=10.1); 129.21 (s, PPh3
para); 133.41 (t%, PPh3 meta, 3,5JCP=12.1 Hz); 137.43
2
(t%, PPh3 ipso, 1,3JCP=49.3 Hz); 204.78 (t, CO, JCP
=
2
4.4. Preparation of
OsH(p-tolyl)(CO)[P(NC4H4)3](PPh3)2 (3)
11.1 Hz); 204.81 (t, CO, JCP=11.06 Hz). 31P-NMR
(CDCl3; l): 9.43 (d, PPh3, 2JPP=30.0 Hz); 83.64 (t,
2
P(NC4H4)3, JPP=31.0 Hz).
Freshly distilled and deoxygenated C6H6 (20 ml) was
added to a Schlenk tube containing Os(p-tolyl)(h2-
O2CH)(CO)(PPh3)2 (200 mg, 0.259 mmol) and
P(NC4H4)3 (60 mg, 0.26 mmol). The colourless solution
was heated to 60 °C for 5 min and then reduced in
volume in vacuo. C6H12 was added to effect crystallisa-
tion of colourless crystals of 3, which were recrystallised
from CH2Cl2–EtOH (25:10 ml) to give pure 3 (194 mg,
80%). Anal. Calc. for C56H50N3OOsP3·CH2Cl2: C,
59.58; H, 4.56; N, 3.65. Found: C, 60.20; H, 4.62; N,
4.17%. IR (cm−1): 1935 w(CO), 2137 w(OsH), 1290,
4.6. Preparation of Os(CO)(CS)[P(NC4H4)3](PPh3)2 (5)
Os(CS)(CO)(PPh3)3 (200 mg, 0.193 mmol) was
treated as in the preparation of complex 4 to yield light
tan crystals of pure 5 (130 mg, 76%). Anal. Calc. for
C50H42N3OOsP3S·0.5CH2Cl2: C, 57.29; H, 4.10; N,
3.97. Found: C, 56.91; H, 4.50; N, 3.81%. IR (cm−1):
1904 w(CO), 1247 w(CS), 1585, 1232, 1180, 1173, 1156,
1
1087, 1071, 1056, 1039, 999, 626, 615, 555. H-NMR
1
1185, 1176, 1089, 1059, 1041, 796, 577, 555. H-NMR
(CDCl3; l): 6.00 (m, P(NC4H4)3); 6.23 (m, P(NC4H4)3),
2
(CDCl3; l): −6.44 (dt, OsH, JHPtrans=129.6 Hz,
7.21–7.42 (m, 30H PPh3). 13C-NMR (C6D6; l): 110.86
2JHPcis=28.8 Hz); 2.43 (s, 3H, C6H4CH3); 6.05 (m,
P(NC4H4)3); 6.06 (m, P(NC4H4)3); 6.92–7.32 (m, 30H
PPh3). 13C-NMR (C6D6; l): 23.0 (s, CH3); 111.35 (d,
P(NC4H4)3), 3JCP=5.0 Hz); 123.50 (d, P(NC4H4)3),
2JCP=6.0 Hz); 129.16 (s, C6H4); 129.31 (s, C6H4);
137.27 (s, C6H4); 127.58 (t%, PPh3 ortho, 2,4JCP=10.1
(d, P(NC4H4)3, JCP=6.0 Hz); 123.67 (d, P(NC4H4)3,
2
3JCP=6.0 Hz); 128.24 (t%, PPh3 ipso, 1,3JCP=37.2 Hz);
127.55 (t%, PPh3 ortho, 2,4JCP=10.1 Hz); 129.50 (s, PPh3
para); 134.26 (t%, PPh3 meta, 3,5JCP=12.1 Hz). 31P-
2
NMR (CDCl3; l): 8.96 (d, PPh3, JPP=35.6 Hz); 83.38
2
(t, P(NC4H4)3, JPP=35.0 Hz).

C.E.F. Rickard et al. / Journal of Organometallic Chemistry 643–644 (2002) 168–173
173
4.7. X-ray crystal structure determination for complex
4
grants-in-aid and through the award of a Doctoral
Scholarship to S.D. Woodgate.
X-ray data collection for 4 was on a Siemens
SMART diffractometer with a CCD area detector,
using graphite monochromated Mo–Ka radiation (u=
References
[1] (a) K.G. Moloy, J.L. Petersen, J. Am. Chem. Soc. 117 (1995)
7696;
,
0.71073 A). Data were integrated and Lorentz and
polarisation correction applied using SAINT [11] soft-
ware. Semi-empirical absorption corrections were ap-
plied based on equivalent reflections using SADABS
[12]. The structures were solved by Patterson and
Fourier methods and refined by full-matrix least-
squares on F2 using programs SHELXS [13] and SHELXL
[14]. All non-hydrogen atoms were refined anisotropi-
cally and hydrogen atoms were included in calculated
positions and refined with a riding model with thermal
parameter 20% greater than Uiso of the carrier atom.
Crystal data and refinement details are given in Table 1.
(b) J.K. Huang, C.M. Haar, S.P. Nolan, W.J. Marshall, K.G.
Moloy, J. Am. Chem. Soc. 120 (1998) 7806;
(c) O. Gonzalez-Blanco, V. Branchadell, Organometallics 16
(1997) 5556;
(d) A. Fernandez, C. Reyes, T.Y. Lee, A. Prock, W.P. Giering,
C.M. Haar, S.P. Nolan, J. Chem. Soc. Perkin Trans. 2 (2000)
1349;
(e) A.L. Fernandez, M.R. Wilson, A. Prock, W.P. Giering,
Organometallics 20 (2001) 3429.
[2] K. Hu¨bler, W.R. Roper, L.J. Wright, Organometallics 16 (1997)
2730.
[3] K. Hu¨bler, U. Hu¨bler, W.R. Roper, P. Schwerdtfeger, L.J.
Wright, Chem.—Eur. J. 3 (1997) 1608.
[4] (a) D.S. Bohle, G.R. Clark, C.E.F. Rickard, W.R. Roper, M.J.
Taylor, J. Organomet. Chem. 348 (1988) 385;
(b) D.S. Bohle, G.R. Clark, C.E.F. Rickard, W.R. Roper, W.B.
Shepard, J. Organomet. Chem. 402 (1991) 375.
[5] (a) W.R. Roper, L.J. Wright, J. Organomet. Chem. 234 (1982) C5;
(b) L.J. Wright, Ph.D Thesis, University of Auckland, 1980.
[6] T.J. Collins, K.R. Grundy, W.R. Roper, J. Organomet. Chem.
231 (1982) 161.
[7] W.R. Roper, J. Organomet. Chem. 300 (1986) 167.
[8] D.S. Bohle, C.E.F. Rickard, W.R. Roper, Organometallics 5
(1986) 1612.
[9] S.M. Maddock, C.E.F. Rickard, W.R. Roper, L.J. Wright,
Organometallics 15 (1996) 1793.
5. Supplementary material
Crystallographic data (excluding structure factors)
for 4 have been deposited with the Cambridge Crystal-
lographic Data Centre as supplementary publication
no. 164866. Copies of this information can be obtained
free of charge from the Director, CCDC, 12 Union
Road, Cambridge, CB2 1EZ, UK (Fax: +44-1223-336-
033; e-mail: deposit@ccdc.cam.ac.uk or www: http://
www.ccdc.cam.ac.uk).
[10] C.E.F. Rickard, W.R. Roper, G.E. Taylor, J.M. Waters, J.
Organomet. Chem. 389 (1990) 375.
[11] SAINT, Area detector integration software, Siemens Analytical
Instruments Inc., Madison, WI, USA, 1995.
[12] G.M. Sheldrick, SADABS, Program for Semi-empirical Absorption
Correction, University of Go¨ttingen, 1997.
[13] G.M. Sheldrick, SHELXS, Program for Crystal Structure Determi-
nation, University of Go¨ttingen, 1997.
[14] G.M. Sheldrick, SHELXL, Program for Crystal Structure Determi-
nation, University of Go¨ttingen, 1997.
Acknowledgements
We thank the University of Auckland Research
Committee for partial support of this work through