A new precursor for organo-osmium complexes

Article abstract of DOI:10.1016/j.ica.2005.09.070

The use of potassium osmate, K₂[OsO₂(OH)₄], as a precursor for some cyclopentadienyl-osmium complexes is described. The X-ray structures of OsBr(PPh₃)₂Cp, OsCl(dppe)Cp and OsX(dppe)Cp^* (X = Cl, Br) are reported.

Full text of DOI:10.1016/j.ica.2005.09.070

Inorganica Chimica Acta 359 (2006) 2644–2649
www.elsevier.com/locate/ica
A new precursor for organo-osmium complexes
a
a,
b
b
Gary J. Perkins , Michael I. Bruce *, Brian W. Skelton , Allan H. White
a
Department of Chemistry, University of Adelaide, Adelaide, SA 5005, Australia
Chemistry M313, School of Biomolecular, Biomedical and Chemical Sciences, University of Western Australia, Crawley, WA 6009, Australia
b
Received 31 August 2005; accepted 19 September 2005
Available online 9 March 2006
Dedicated in friendship and admiration to Brian James for his 70th birthday.
Abstract
The use of potassium osmate, K2[OsO2(OH)4], as a precursor for some cyclopentadienyl-osmium complexes is described. The X-ray
structures of OsBr(PPh3)2Cp, OsCl(dppe)Cp and OsX(dppe)Cp* (X = Cl, Br) are reported.
ꢀ 2006 Elsevier B.V. All rights reserved.
Keywords: Cyclopentadienyl; Osmium; Phosphine; X-ray structures
1. Introduction
presence of iron(II) or (III) compounds limits the applicabil-
ity of this route when cyclopentadienyl ligands are involved.
Recent changes to rules covering transport of hazardous
materials by air have resulted in there being some reluc-
tance to transport OsO4 and other starting materials which
are less problematical have been sought. One of these is so-
called ‘‘potassium osmate’’ which is formulated as the tet-
rahydroxo-dioxo-osmate(VI), K2[OsO2(OH)4]. Conversion
of OsO4 to this salt is effected in ethanolic KOH [6]. We
have recently developed methods for entry into cyclopenta-
dienyl-osmium chemistry from this material and present
below one-pot syntheses of several common precursors.
There is increasing interest in the organometallic chemis-
try of osmium as the nature of the differences from its lighter
congenor ruthenium become more apparent. The usual pre-
cursor for these complexes is osmium(VIII) oxide, OsO4, a
pale yellow solid (m.p. 31 ꢁC) which has an appreciable
vapour pressure at ambient temperatures and which can
cause severe physiological problems if appropriate care is
not taken [1]. The use of dilute solutions for staining or other
preparation of organic samples for histological study is well-
known [2]. Conversion of OsO4 to other starting materials
has been documented in books of syntheses, tested proce-
dures for the rather insoluble (NH4)2[OsBr6] (by direct reduc-
tion with conc. aqueous HBr) [3a] or (NH4)2[OsCl6] [by
treatment with conc. HCl and Fe(II)] [3b] being examples.
The difficulty in reduction of OsO4 directly by concen-
trated HCl has resulted in bromo-osmium complexes being
generally prepared for use as precursors. The intermediate
H2[OsBr6] can be used for the synthesis of some cyclopenta-
dienyl-osmium complexes, such as OsBr(PPh3)2Cp [4] or
OsCp2 [5], the further reduction to osmium(II) being
achieved with an excess of PPh3 or zinc, respectively. The
2. Results and discussion
Potassium osmate is a brown solid which is soluble in hot
concentrated HCl with reaction to form a yellow solution,
but unlike OsO4, insoluble in aromatic hydrocarbons (ben-
zene and toluene), alcohols (MeOH, EtOH), dichlorometh-
ane or acetone. In order to reduce the osmium, we have
heated it in refluxing concentrated HCl overnight. The
excess of HCl was removed by distillation to give a brick-
red solid, after which a solution of PPh3 in aqueous t-buta-
nol which had been degassed by argon was added to the res-
idue. After heating at reflux point for 18 h, the resulting
green solution was allowed to cool to give a green precipi-
*
Corresponding author. Tel.: +618 8303 5939; fax: +61 8 8303 4358.
E-mail address: michael.bruce@adelaide.edu.au (M.I. Bruce).
0020-1693/$ - see front matter ꢀ 2006 Elsevier B.V. All rights reserved.
doi:10.1016/j.ica.2005.09.070

G.J. Perkins et al. / Inorganica Chimica Acta 359 (2006) 2644–2649
2645
tate which was then collected, washed with ethanol and hex-
ane and dried under reduced pressure to give OsCl2(PPh3)3
in 99% yield. This compound has also been prepared
directly from (NH4)2[OsCl6] and PPh3 in t-butanol [7].
Introduction of a cyclopentadienyl group was accom-
plished by treating OsCl2(PPh3)3 with LiCp in thf for
15 min. After removal of solvent, the residue was extracted
with the minimum amount of benzene and filtered through a
short silica column. Excess PPh3 was eluted with hexane and
the yellow OsCl(PPh3)2Cp (1-Os) (76% yield) was washed
off the column with 10% acetone–hexane. Ready exchange
of PPh3 for dppe was achieved by heating the two reactants
in refluxing toluene overnight. Similar purification on a sil-
ica column afforded OsCl(dppe)Cp (2-Os) in 81% yield.
The pentamethylcyclopentadienyl analogue was obtained
in a one-pot procedure by adding a degassed solution of pen-
tamethylcyclopentadiene in aqueous ethanol to the residue
obtained after heating potassium osmate with conc. HCl.
The mixture was heated at reflux point for 1 h before adding
1,5-cyclooctadiene and continued heating at reflux overnight.
After this time, evaporation of the solvent, extraction with
diethyl ether and further evaporation gave a residue [proba-
bly OsCl(cod)Cp*] which was treated directly with a solution
of dppe in heptane. After heating at reflux point for 18 h, the
yellow precipitate which separated was filtered off. Chroma-
tography of the filtrate (silica gel) afforded a further amount
of pure yellow OsCl(dppe)Cp* (3-Os) (combined yield 61%).
112
131
111
122
P(1)
121
132
5
4
Os
3
Br
2
1
P(2)
221
222
211
231
212
232
Fig. 1. Projection of a single molecule of OsBr(PPh3)2Cp (4-Os) down the
cp-centroid/metal atom vector.
2.1. Molecular structures
In the course of this work, we determined the molecular
structures of OsBr(PPh3)2Cp (4-Os) (obtained by the previ-
ously reported route from H2[OsBr6], PPh3 and
cyclopentadiene and crystallised from benzene/hexane),
OsCl(dppe)Cp (2-Os) (obtained as described above and
crystallised from dichloromethane/hexane), OsCl(dppe)Cp*
(3-Os), and [obtained from OsBr(PPh3)2Cp and dppe and
crystallised from benzene/methanol]. An earlier structural
determination was carried out on a mixture of OsX(dp-
pe)Cp* (X = Br/Cl 82/18, 3/5-Os), obtained when 5-Os
was crystallised from chloroform. These molecules are illus-
trated in Figs. 1–3 and selected bond distances are presented
in Table 1, together with values previously reported for the
ruthenium analogues. As can be seen, these are further
examples of Group 8 complexes of the type MX(PP)Cp0,
all having pseudo-octahedral geometry at the metal centre.
The structure of OsBr(PPh3)2Cp (4-Os) as its dichloro-
methane solvate has been reported previously, together with
the isomorphous and isostructural ruthenium compound 4-
Ru [8]. The present study, carried out on a solvent-free crys-
tal, shows surprising and significant differences in the coor-
dination geometry around the osmium centre. Thus, in the
present study, the Os–P distances are longer by up to 15
standard deviations, while the Os–Br distance is also longer,
The reasons for these changes is not obvious; the presence of
the solvent molecule in a unit cell of otherwise similar vol-
ume creating steric pressure or other interactions on the
complex may be relevant, but the difference may also reflect
the caution needed in using results derivative of r.t. data
without libration correction for quantitative purposes.
R5
M
P
P
X
X
PP
(PPh3)2
dppe
dppe
(PPh3)2
dppe
C5R5
Cp
Cp
Cp*
Cp
Cp*
Cl
Cl
Cl
Br
Br
1-M
2-M
3-M
4-M
5-M
˚
by 0.041 A. The increase in Os–C(cp) distances is less signif-
˚
icant, average values being 2.218 and 2.177 A. These changes
M = Fe, Ru, Os
result in a slight opening of the P–Os–P and P–Os–Br angles.

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G.J. Perkins et al. / Inorganica Chimica Acta 359 (2006) 2644–2649
122
112
031
021
111
111
121
P(1)
121
P(1)
02
122
112
102
101
105
03
10
Br
Cl
Os
01
2
1
011
20
Os
05
103
04
P(2)
P(2)
041
104
221
221
212
211
051
222
212
211
222
Fig. 2. Projection of a single molecule of OsCl(dppe)Cp (2-Os) down the
cp-centroid/metal atom vector.
Fig. 3. Projection of a single molecule of OsBr(dppe)Cp* (5-Os) down the
cp-centroid/metal atom vector.
(Fe), 220 (Ru) or 210 mV (Os), as expected when the more
strongly electron-donating Cp* ligand replaces Cp. The
dppe complexes are more readily oxidised than the bis-
PPh3 analogues, while replacement of Cl by Br results in
an increase of oxidation potential of ca. 25 mV. Irreversible
second oxidations, assigned to M(III)/M(IV), were found
for four of the compounds, although somewhat surpris-
ingly, not for some of the Cp* complexes.
As expected, the similarity of the covalent radii of ruthe-
nium and osmium (Ru: 1.26, Os 1.28 A) [9] results in there
˚
being essentially no differences in the M–P and M–Cl bond
lengths in MCl(dppe)Cp and MX(dppe)Cp*, with the
exception of the Os–Br and Ru–Cl bonds in the latter,
˚
which differ by 0.13 A (cf. the difference in covalent radii
˚
of Cl and Br, 0.15 A). The M–C(cp) distances are some-
what shorter than the M–C(cp*) separations on account
of the increased bulk of the latter ligand. Significant differ-
ences are found in the P–M–X angle pair between the PPh3
and dppe complexes, contingent on the effects of the Ru–P–
C–C–P ring constraint in the latter.
3. Conclusions
We have described useful routes into selected organo-
osmium precursors from a more readily available source
of osmium, namely K2[OsO2(OH)4] Æ 2H2O. Reliable and
improved routes into the complexes OsX(PP)Cp0 (X = Cl,
Cp0 = Cp PP = (PPh3)2, dppe; X = Cl, Cp0 = Cp*,
PP = dppe) are also reported.
2.2. Electrochemistry
It was of interest to compare the ease of oxidation of
these complexes, together with several analogous com-
pounds. Cyclic voltammograms were measured and
showed one or two oxidation processes, the potentials of
which are summarised in Table 2. Several comparisons
can be made, the most pertinent being the change in a series
of MCl(dppe)Cp0 as the Group is descended. For both Cp
and Cp* compounds, the ease of oxidation M(II)/M(III)
increases as Fe > Os > Ru, with the Cp* derivatives being
more easily oxidised than the Cp compounds by ca. 280
4. Experimental
4.1. General
All reactions were carried out under dry argon, although
normally no special precautions to exclude air were taken
during subsequent work-up. Common solvents were dried,
distilled under argon and degassed before use.

G.J. Perkins et al. / Inorganica Chimica Acta 359 (2006) 2644–2649
2647
Table 1
Selected bond distances (A) and angles (ꢁ) in MX(PP)Cp
0
˚
Complex
1-Rua
1-Osb
2-Ruc
2-Os
3-Rud
3-Os
MX
PP
Cp0
RuCl
(PPh3)2
Cp
OsCl
(PPh3)2
Cp
RuCl
dppe
Cp
OsCl
dppe
Cp
RuCl
dppe
Cp*
OsCl
dppe
Cp*
Solvate
CH2Cl2
CH2Cl2
CHCl3
CH2Cl2
˚
Bond distances (A)
M–P(1)
M–P(2)
2.323(1)
2.329(1)
2.320(2)
2.319(2)
2.2688(7)
2.2863(7)
2.2705(7)
2.2797(7)
2.2882(5)
2.2812(5)
2.2714(9)
2.2694(8)
M–X
M–C(Cp)
(av.)
2.448(1)
2.159–2.218(3)
2.20(1)
2.460(2)
2.183–2.235(6)
2.21(2)
2.4466(7) [Cl]
2.169–2.227(4)
2.20(3)
2.4488(8) [Cl]
2.172–2.243(4)
2.22(5)
2.4532(5) [Cl]
2.219–2.252(2)
2.24(1)
2.4437(9) [Cl]
2.214–2.250(4)
2.230(14)
Bond angles (ꢁ)
P(1)–M–P(2)
P(1)–M–X
103.79(3)
88.29(3)
89.15(3)
103.23(6)
88.44(6) [Cl]
89.77(5) [Cl]
83.48(2)
83.04(3) [Cl]
93.28(3) [Cl]
83.43(3)
84.00(3) [Cl]
93.33(3) [Cl]
82.15(2)
81.93(2) [Cl]
90.93(2) [Cl]
82.12(3)
82.22(3) [Cl]
90.74(3) [Cl]
P(2)–M–X
Complex
4-Rue
4-Os
4-Ose
5-Os
3/5-Os
MX
PP
Cp0
RuBr
(PPh3)2
Cp
OsBr
(PPh3)2
Cp
OsBr
(PPh3)2
Cp
OsBr
dppe
Cp*
Os(Br/Cl)
dppe
Cp*
Solvate
CH2Cl2
CH2Cl2
˚
Bond distances (A)
M–P(1)
M–P(2)
M–X
M–C(Cp)
(av.)
2.323(2)
2.329(2)
2.5683(8) [Br]
2.172–2.220(5)
2.20(2)
2.327(2)
2.318(2)
2.585(1) [Br]
2.19–2.24(1)
2.22(2)
2.290(2)
2.297(2)
2.5438(9) [Br]
2.150–2.197(6)
2.18(2)
2.2870(6)
2.2780(7)
2.5818(4) [Br]
2.229–2.260(3)
2.242(13)
2.2851(5)
2.2781(5)
2.5708(3) [Br/Cl]
2.228–2.261(2)
2.240(14)
Bond angles (ꢁ)
P(1)–M–P(2)
P(1)–M–X
103.18(5)
88.36(4) [Br]
90.77(4) [Br]
104.28(8)
89.50(6) [Br]
90.94(6) [Br]
103.13(7)
88.45(5) [Br]
90.48(5) [Br]
82.11(2)
82.39(2) [Br]
91.84(2) [Br]
82.13(2)
82.42(1) [Br/Cl]
91.95(1) [Br/Cl]
P(2)–M–X
a
Ref. [11].
Ref. [8a].
Ref. [12].
Ref. [13].
b
c
d
e
Ref. [8b].
on a Varian 2000 instrument (1H at 300.13 MHz, 13C at
75.47 MHz, 31P at 121.503 MHz). Samples were dissolved
in CDCl3 or C6D6 contained in 5 mm sample tubes. Chem-
ical shifts are given in ppm relative to internal tetramethylsi-
Table 2
Electrochemical data for MCl(dppe)Cp0 (M = Fe, Ru, Os; Cp0 = Cp, Cp*)
Complex
E1
E2
2-Fe
3-Fe
1-Ru
FeCl(dppe)Cp
FeCl(dppe)Cp*
RuCl(PPh3)2Cp
RuCl(PPh3)2Cp*
RuCl(dppm)Cp*
RuCl(dppe)Cp
RuCl(dppe)Cp*
OsBr(PPh3)2Cp
OsCl(dppe)Cp
OsCl(dppe)Cp*
OsBr(dppe)Cp*
+0.04
ꢀ0.24
+0.595
+0.385
+0.245
+0.46
+0.28
+0.490
+0.38
+0.17
+0.195
+0.68
1
lane for H and 13C NMR spectra and external H3PO4 for
31P NMR spectra. Electrospray mass spectra (ES-MS) were
obtained from samples dissolved in MeOH unless otherwise
indicated. Solutions were injected into a Finnegan LCQ
spectrometer via a 10 ml injection loop. Nitrogen was used
as the drying and nebulising gas.
2-Ru
3-Ru
4-Os
2-Os
3-Os
5-Os
+1.37
+1.18
+1.19
4.3. Reagents
Conditions: 0.1 M [NBu4]PF6/CH2Cl2, scan rate 100 mV sꢀ1, 293 K, Pt
electrodes.
Potassium osmate was obtained from Johnson Matthey
and used as received.
4.2. Instruments
4.4. Preparation of OsCl2(PPh3)3
IR spectra were obtained on a Bruker IFS28 FT-IR spec-
trometer. Nujol mull spectra were obtained from samples
mounted between NaCl discs. NMR spectra were recorded
A solution of K2[OsO2(OH)4] (2.00 g, 5.43 mmol) in
conc. HCl (300 ml) was heated at reflux point for 18 h.

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G.J. Perkins et al. / Inorganica Chimica Acta 359 (2006) 2644–2649
1
The excess HCl was evaporated and a degassed solution of
PPh3 (10.0 g, 38.13 mmol) in t-butanol (420 ml) and water
(150 ml) was added to the solid residue. After heating a
reflux point for 18 h, after which time a green suspension
had formed, the mixture was cooled and the precipitate fil-
tered off, washed with EtOH and hexane and dried in vac-
uum to give OsCl2(PPh3)3 (5.63 g, 99%).
696s, 671w cmꢀ1. H NMR (C6D6): d 2.17, 2.38 (2 · m,
2 · 2H, CH2), 4.52 (s, 5H, Cp), 6.84–8.02 (m, 20H, Ph).
13C NMR (C6D6): d 29.12–30.44 (m, CH2), 75.75 [t,
J(CP) 2.5 Hz, Cp], 128.07–143.56 (m, Ph). 31P NMR
(C6D6): d 46.6. ES-MS (positive ion, MeOH, m/z): 655,
[M–Cl]+.
4.7. Preparation of OsCl(dppe)Cp* (3-Os)
4.5. Preparation of OsCl(PPh3)2Cp (1-Os)
A solution of K2[OsO4(OH)2] (138 mg, 0.42 mmol) in
conc. HCl (20 ml) was heated at reflux point for 18 h.
The excess HCl was distilled off before adding a degassed
Thf (50 ml) was added to a solid mixture of LiCp
(30 mg, 0.45 mmol; from LiBu and C5H6 in hexane, fol-
lowed by filtration of the white LiCp and drying) and
OsCl2(PPh3)3 (468 mg, 0.45 mmol) and the solution was
stirred for 15 min. After removal of solvent under vaccum,
the residue was taken up in a minimum amount of benzene
and chromatographed (silica gel). Hexane removed PPh3
and 10% acetone–hexane eluted yellow OsCl(PPh3)2Cp
solution
of
pentamethylcyclopentadiene
(0.1 ml,
0.62 mmol) in aqueous ethanol (2 + 15 ml). This mixture
was heated under reflux for 1 h, 1,5-cyclooctadiene
(0.26 ml, 2.10 mmol) was added and the mixture heated a
further 18 h. After removal of solvent, the residue was
extracted with Et2O and the filtered solution was again
evaporated. After addition of dppe (182 mg, 0.46 mmol)
in heptane (20 ml) and heating under reflux for 18 h, the
yellow precipitate which had separated was filtered off
(176 mg). The filtrate was then chromatographed (silica
gel column, eluted with 1% acetone–hexane) to give a fur-
ther amount of pure yellow OsCl(dppe)Cp* (3-Os) (total
yield 192 mg, 61%). Anal. Calc. for (C41H49ClOs-
P2 Æ CH2Cl2): C, 56.95; H, 5.18; M, 760. Found: C, 56.83;
H, 5.23%. M, 760. IR (nujol, cmꢀ1): 1306w, 1155w,
1
(1-Os) (234 mg, 76%). H NMR (CDCl3): d 4.37 (s, 5H,
3
Cp), 7.15–7.39 (m, 30H, Ph). P NMR (CDCl3): d ꢀ1.20
(s, PPh3). ES-MS (positive ion, MeOH, m/z): 781,
[MꢀCl]+; 519, [Os(PPh3)Cp]+.
4.6. Preparation of OsCl(dppe)Cp (2-Os)
A solution of OsCl(PPh3)2Cp (1.8 g, 2.2 mmol) and
dppe (964 mg, 2.42 mmol) in toluene (100 ml) was heated
at reflux point for 18 h. The mixture was filtered and the fil-
trate was chromatographed on silica gel, washing off dis-
placed PPh3 with hexane and eluting the product with
10% acetone–hexane to give yellow OsCl(dppe)Cp (2-Os)
(1.23 g, 81%). Anal. Calc. for (C36H39ClOsP2 Æ CH2Cl2):
C, 49.65; H, 4.04. Found: C, 49.63; H, 4.10%. M, 690. IR
(nujol): 1306w, 1180w, 1095s, 1026w, 998w, 791m, 749m,
1
1094s, 1027m, 867w, 788m, 693s, 668vs, 646w. H NMR
(C6D6): d 1.57 (s, 15H, C5Me5), 1.97–2.09, 2.49–2.59
(2 · m, 2 · 2H, CH2), 7.05–7.82 (m, 20H, Ph). 13C NMR
(C6D6): d 10.18 (s, C5 Me5), 30.63–31.24 (m, CH2), 86.10
[t, J(CP) = 2.6 Hz, C5Me5, 127.77–140.78 (m, Ph). 31P
NMR (C6D6): d 43.1. ES-MS (positive ion, MeOH): 760,
M+; 725, [MꢀCl]+.
Table 3
Crystal data and refinement details
Complex
2-Os
3-Os
4-Os
5-Os
3/5-Os
Formula
MW
C
774.12
31H29ClOsP2 Æ CH2Cl2
C36H39ClOsP2
759.31
C41H35BrOsP2
859.78
C36H39BrOsP3
803.76
C36H39Br0.822Cl0.178OsP2
795.89
Crystal system
Space group
monoclinic
C2/c
28.292(2)
10.8530(7)
19.716(1)
monoclinic
P21/n
11.070(2)
17.773(2)
16.7070(9)
triclinic
monoclinic
P21/n
11.167(1)
17.764(2)
16.792(2)
monoclinic
P21/n
11.1573(9)
17.774(2)
ꢀ
P1
˚
a (A)
14.416(3)
11.208(3)
11.779(3)
70.305(3)
84.699(3)
67.021(3)
1648
˚
b (A)
˚
c (A)
16.782(1)
a (ꢁ)
b (ꢁ)
c (ꢁ)
107.432(2)
109.136(1)
109.387(2)
109.379(2)
3
˚
V (A )
5776
3105
3142
3140
qc
1.780
1.624
1.732
1.699
1.684
Z
8
4
2
4
4
2hmax (ꢁ)
l(Mo Ka) (mmꢀ1
Tmin/max
68
4.8
0.78
58
4.3
0.87
58
5.2
0.60
75
5.5
0.77
75
5.2
0.68
)
Crystal dimensions (mm3)
0.22 · 0.20 · 0.15
48865
11775 (0.040)
9056
0.26 · 0.22 · 0.18
28892
7847 (0.023)
7000
0.12 · 0.05 · 0.04
16264
8069 (0.061)
6452
0.12 · 0.10 · 0.08
61533
16020 (0.054)
10876
0.13 · 0.10 · 0.09
62129
16196 (0.029)
12874
Ntot
N (Rint
No
)
R
0.032
0.024
0.053
0.030
0.034
Rw (nw)
0.0038 (4)
0.048 (1.4)
0.061 (6)
0.024 (4)
0.028 (2)

G.J. Perkins et al. / Inorganica Chimica Acta 359 (2006) 2644–2649
2649
4.8. Structure determinations
336 033; e-mail: deposit@ccdc.cam.ac.uk or www: http://
www.ccdc.cam.ac.uk.
Full spheres of diffraction data were measured at ca.
153 K using a Bruker AXS CCD area-detector instrument.
Ntot reflections were merged to N unique (Rint cited) after
‘‘empirical’’/multiscan absorption correction (proprietary
software), No with F > 4r(F) being used in the full-matrix
least-squares refinements. All data were measured using
Acknowledgements
We thank ARC for support of this work, Johnson Mat-
they plc, Reading, for a generous loan of potassium os-
mate, and Ms. K.A. Kramarczuk who supplied samples
of OsBr(PPh3)2Cp and OsBr(dppe)Cp*.
˚
monochromatic Mo Ka radiation, k = 0.71073 A. Aniso-
tropic displacement parameter forms were refined for the
non-hydrogen atoms, (x,y,z,Uiso)h being constrained at
References
estimates. Conventional residuals R, Rw on |F| are quoted
[weights: (r2(F) + 0.000nwF2)ꢀ1]. Neutral atom complex
scattering factors were used; computation used the XTAL
3.7 program system [10]. Pertinent data are recorded in
Tables 1 and 3.
[1] (a) L. Wo¨hler, L. Metz, Z. Anorg. Chem. 149 (1925) 301;
´
(b) J.C. Bailar, H.J. Emeleus, R.S. Nyholm, A.F. Trotman Dickenson
(Eds.), Comprehensive Inorganic Chemistry, vol. 3, Pergamon Press,
Oxford, 1973, p. 1216.
[2] J.S. Hanker, D.K. Romanovicz, H. Padykula, J. Histochem. 49
(1976) 263.
4.9. Variata
[3] (a) F.P. Dwyer, J.W. Hogarth, Inorg. Synth. 5 (1957) 204;
(b) F.P. Dwyer, J.W. Hogarth, Inorg. Synth. 5 (1957) 206.
[4] M.I. Bruce, N.J. Windsor, Aust. J. Chem. 30 (1977) 1601.
[5] J.C.A. Boeyens, D.C. Levendis, M.I. Bruce, M.L. Williams, J. Cryst.
Spectrosc. Res. 16 (1986) 519.
[6] J.M. Malin, Inorg. Synth. 20 (1980) 61.
[7] (a) G.P. Elliott, N.M. McAuley, W.R. Roper, Inorg. Synth. 26
(1989) 184;
3-Os, 5-Os and 3/5-Os were isomorphous and refined in
the same cell and coordinate setting, the halide in the latter
being modelled as a Br/Cl composite, Br site occupancy
0.822(2) with Cl complementary 3-Os was refined on F2.
4-Os is isomorphous with the previously determined
Ru/Cl analogue [11] and was refined in the same cell and
coordinate setting.
(b) P.R. Hoffman, K.G. Caulton, J. Am. Chem. Soc. 97 (1975) 4221.
[8] (a) M.I. Bruce, M.L. Williams, J.M. Patrick, A.H. White, Aust. J.
Chem. 36 (1983) 1353;
(b) M.I. Bruce, P.J. Low, B.W. Skelton, E.R.T. Tiekink, A. Werth,
A.H. White, Aust. J. Chem. 48 (1995) 1887.
5. Supplementary material
[9] www.webelement.com.
Full details of the structure determinations (except
structure factors) have been deposited with the Cambridge
Crystallographic Data Centre as CCDC Nos. 282442–
282444, 298959, 298960. Copies of this information may
be obtained free of charge from The Director, CCDC, 12
Union Road, Cambridge CB2 1EZ, UK, fax: + 44 1223
[10] S.R. Hall, D.J. du Boulay, R. Olthof-Hazekamp (Eds.), The XTAL 3.7
System, University of Western Australia, 2000.
[11] E.R.T. Tiekink, Z. Krist. 198 (1992) 158.
[12] W.H. Pearson, J.E. Shade, J.E. Brown, T.E. Bitterwolf, Acta
Crystallogr., Sect. C 52 (1996) 1106.
[13] M.I. Bruce, B.G. Ellis, P.J. Low, B.W. Skelton, A.H. White,
Organometallics 22 (2003) 3184.