Organo-Group 15 derivatives of triosmium clusters containing naphthyl ligands

Article abstract of DOI:10.1016/j.ica.2003.09.001

Reactions of the clusters Os₃(μ-H)₂(μ ₃-1-OC₁₀H₆)(CO)₉, 1, and Os ₃(μ-H)(μ-2-OC₁₀H₇)(CO)₁₀, 2, with the group 15 ligands EPh₃ (E=P, As

Full text of DOI:10.1016/j.ica.2003.09.001

Inorganica Chimica Acta 357 (2004) 769–774
www.elsevier.com/locate/ica
Organo-Group 15 derivatives of triosmium clusters
containing naphthyl ligands
*
Mien Wei Lum, Weng Kee Leong
Department of Chemistry, National University of Singapore, Kent Ridge, Singapore 119260, Singapore
Received 27 May 2003; accepted 3 September 2003
Abstract
Reactions of the clusters Os3(l-H)2(l3-1-OC10H6)(CO)9, 1, and Os3(l-H)(l-2-OC10H7)(CO)10, 2, with the group 15 ligands EPh3
(E ¼ P, As, Sb) generally afforded the mono- and, or disubstituted derivatives. These derivatives tend to decompose during chro-
matographic separations on silica gel; thus one of the decomposition products from the reaction of 1 with PPh3 has been identified
as Os(H)2(CO)2(PPh3)2, 3. The molecular structures of 3, as well as the derivatives Os3(l-H)2(l3-1-OC10H6)(CO)8(AsPh3), 4, Os3(l-
H)2(l3-1-OC10H6)(CO)7(SbPh3)2, 5c, Os3(l-H)(l-2-OC10H7)(CO)8(AsPh3)2, 7b, and Os3(l-H)(l-2-OC10H7)(CO)8(SbPh3)2, 7c,
have been determined by single crystal X-ray diffraction studies.
Ó 2003 Elsevier B.V. All rights reserved.
Keywords: Osmium; Naphthyl; Group 15 ligands
1. Introduction
2. Results and discussion
We have been interested in whether cluster-bound
substrates may exhibit unusual reactivity compared to
the free ligands and hence be gainfully employed in or-
ganic transformations [1]. An interesting class of sub-
strates are the aromatics; for instance, it has been shown
that cluster-bound quinolines react with nucleophiles
with a regiochemistry different from that of the free
quinolines [2]. Similarly, cluster-bound phenylenes can
undergo Friedel–Crafts reactions [3] and carbonylation
[4]. The anchoring of naphthols onto a triosmium cluster
has been reported earlier by Deeming and coworkers [5]
and recently re-investigated by us [6]. Our ultimate intent
was to examine the effect of the cluster on the chemistry
of the naphthols. Part of the investigation involved der-
ivatisation of the naphthyl clusters with group 15 ligands,
which would allow for modification of the stereoelec-
tronic properties of the cluster. We would like to report
here our attempts at this with the group 15 ligands EPh3
(E ¼ P, As and Sb) on the clusters Os3(l-H)2(l3-1-
OC10H6)(CO)9, 1, and Os3(l-H)(l-2-OC10H7) (CO)10, 2.
Substitution reactions involving PPh3 occurred with
great ease, while chemical activation with TMNO was
required with SbPh3 and AsPh3. The reaction of 1 with
PPh3 gave an orange solid (A) that decomposed during
attempts at chromatographic separation. One of the
decomposition products was the mononuclear complex
trans-Os(H)2(CO)2(PPh3)2, 3 [7]. This has been charac-
terised by a single crystal X-ray crystallographic study;
the ORTEP diagram is shown in Fig. 1, together with
selected bond parameters. The structural and spectro-
scopic data are in accord with this being a typical di-
hydride species [8].
The reaction of 1 with AsPh3 or SbPh3 permitted the
isolation of the disubstituted derivatives, viz., Os3(l-
H)2(l-1-OC10H6)(CO)7(AsPh3)2, 5b, and Os3(l-H)2(l-
1-OC10H6)(CO)7(SbPh3)2, 5c, respectively. In the case of
AsPh3, the monosubstituted derivative Os3(CO)7(l-
H)2(l-1-OC10H6)(AsPh3), 4b, was also isolated. Both 4b
and 5c were characterised by single crystal X-ray crys-
tallographic studies; the ORTEP diagrams and selected
bond parameters are given in Figs. 2 and 3, respectively.
The structural parameters for 4b and 5c are generally
unremarkable, although it is interesting to note that
* Corresponding author. Tel.: 65-68745131; fax: 65-67791691.
E-mail address: chmlwk@nus.edu.sg (W.K. Leong).
0020-1693/$ - see front matter Ó 2003 Elsevier B.V. All rights reserved.
doi:10.1016/j.ica.2003.09.001

770
M.W. Lum, W.K. Leong / Inorganica Chimica Acta 357 (2004) 769–774
Fig. 1. ORTEP diagram (organic hydrogens omitted, 50% probability
thermal ellipsoids) and selected bond parameters for 3. Os(1)–
ꢀ
ꢀ
P(1) ¼ 2.3621(11) A; Os(1)–P(2) ¼ 2.3541(11) A; Os(1)–C(1) ¼ 1.932(6)
Fig. 3. ORTEP diagram (organic hydrogens omitted, 50% probability
ꢀ
ꢀ
ꢀ
ꢀ
A; Os(1)–C(2) ¼ 1.923(5) A; O(1)–C(1) ¼ 1.138(6) A; O(2)–
thermal ellipsoids) for molecule A of 5c. Os(11)–Os(12) ¼ 2.8420(13) A;
ꢀ
C(2) ¼ 1.148(6) A; \P(1)Os(1)P(2) ¼ 163.08(4)°; \C(1)Os(1)C(2)
ꢀ
ꢀ
Os(11)–Os(13) ¼ 2.8255(13) A; Os(12)–Os(13) ¼ 3.0616(13) A; Os(11)–
¼ 97.9(2)°.
ꢀ
ꢀ
O(1) ¼ 2.188(14) A; Os(12)–O(1) ¼ 2.125(17) A; Os(12)–C(16) ¼ 2.06(2)
ꢀ
ꢀ
ꢀ
A; Os(11)–Sb(14) ¼ 2.6420(17) A; Os(13)–Sb(15) ¼ 2.6123(18) A;
\Os(11)Os(12)Os(13) ¼ 57.04(3)°; \Os(12)Os(11)Os(13) ¼ 65.39(3)°;
\Os(11)Os(13)Os(12) ¼ 57.56(3)°; \Os(11)O(1)Os(12) ¼ 82.4(5)°.
both have an EPh3 substitution at the unbridged os-
mium. This may suggest that the initial site of nucleo-
philic attack is at this osmium.
The reaction of 2 with PPh3 afforded an orange solid
(B) which was unstable on silica; the monosubstituted
derivative Os3(l-H)(l-2-OC10H7)(CO)9(PPh3), 6a, iden-
tified on the basis of the similarity of its IR carbonyl
stretch pattern with those for clusters of the type Os3(l-
H)(l-OR)(CO)9(L) (where R ¼ H, alkyl and Ph;
L ¼ PPh3 and P(OMe)3) [9], was isolated from the su-
substituted alkoxy-bridged triosmium clusters [10]; the
1H NMR spectrum of 6a showed one set of doublet at
)12.44 ppm (2JPH ¼ 6 Hz), and given the steric bulk of
the naphthyl, the phosphine probably occupied position
C (Fig. 4).
The reaction of 2 with AsPh3 gave the disubstituted
derivative Os3(l-H)(l-2-OC10H7)(CO)8(AsPh3)2, 7b,
and another cluster C. The latter has a mass spectrum
that suggests the formulation Os3(l-H)(l-2-OC10H7)
(CO)9(AsPh3), but its IR spectrum is very different from
that of 6a. On the other hand, the reaction with SbPh3
gave three major products which were identified as
the substituted derivatives Os3(l-H)(l-2-OC10H7)(CO)9
(SbPh3), 6c, Os3(l-H)(l-2-OC10H7)(CO)8(SbPh3)2, 7c,
and the cluster Os3(CO)10 (SbPh3)2, 8. The structures of
7b and 7c have been confirmed by single crystal X-ray
crystallographic studies; the ORTEP diagram for 7b is
shown in Fig. 5 and selected bond parameters for 7b and
7c are tabulated in Table 1. In contrast to 5c, these
clusters have disubstitution by the EPh3 ligands at the
two naphthyl-bridged osmiums; this is probably attrib-
utable to steric effects of the naphthyl ring in 5c. As may
2
pernatant. The magnitude of the JPH has been used to
assess the position of substitution in similar phosphite-
Fig. 2. ORTEP diagram (organic hydrogens omitted, 50% probability
ꢀ
thermal ellipsoids) for 4b. Os(1)–Os(2) ¼ 2.8109(7) A; Os(1)–
ꢀ
ꢀ
Os(3) ¼ 3.0603(7) A; Os(2)–Os(3) ¼ 2.8251(7) A; Os(1)–O(10) ¼
ꢀ
ꢀ
ꢀ
2.111(8) A; Os(2)–O(10) ¼ 2.138(8) A; Os(1)–C(70) ¼ 2.101(12) A;
ꢀ
Os(3)–As(4) ¼ 2.4675(13) A; \Os(1)Os(2)Os(3) ¼ 65.775(17)°; \Os(2)
Os(1)Os(3) ¼ 57.335(16)°; \Os(1)Os(3)Os(2) ¼ 56.890(15)°; \Os(1)
O(10)Os(2) ¼ 82.8(3)°.
Fig. 4. Possible substitution positions at an alkoxy-bridged osmium;
Newman projection along the bridged Os–Os bond.

M.W. Lum, W.K. Leong / Inorganica Chimica Acta 357 (2004) 769–774
771
the naphthyl clusters appear to be more complicated
than was expected; in many cases, the initial reaction
product(s) obtained decomposed during chromato-
graphic separation.
3. Experimental
3.1. General procedures
All reactions and manipulations were carried out
under nitrogen by using standard Schlenk techniques.
NMR spectra were recorded at ambient temperature on
a Bruker ACF-300 FT-NMR spectrometer in CDCl3
unless otherwise stated. IR spectra were recorded as
hexane solutions, unless otherwise stated. Microanalyses
were carried out by the microanalytical laboratory at the
National University of Singapore. All reagents were
from commercial sources and used as supplied. Prepa-
ration of the clusters (l-H)2(l3-1-OC10H6)(CO)9, 1, and
Os3(l-H)(l-2-OC10H7)(CO)10, 2, has been reported
elsewhere [5].
Fig. 5. ORTEP diagram (organic hydrogens omitted, 50% probability
thermal ellipsoids) for 7b.
be expected, a comparison between the structural pa-
rameters of 7b and 7c shows that there are some differ-
ences in the bond parameters associated with the
triosmium core which may be attributed to the different
stereoelectronic properties of arsine versus stibine.
The 1H NMR spectrum of 7b showed two singlet
metal hydride resonances at )10.28 and )10.43 ppm, in
a relative intensity ratio of 6:5, suggesting that there are
two geometrical isomers. The solid-state structure is that
in which the two AsPh3 ligands are in position A
(Fig. 4), and hence presumably the other isomer may
have one or both ligands in the sterically more favour-
3.2. Reaction of 1 with PPh3
Triphenylphosphine (48.3 mg, 167 lmol) was added
to a solution of 1 (35.9 mg, 37.8 lmol) in hexane (7.5
ml). The mixture was allowed to stir at room tempera-
ture for about 4 d. The colour of the solution turned
from yellow to orange, accompanied by precipitation of
an orange solid. The orange precipitate (A) was sepa-
rated by decantation. (Yield ¼ 23 mg. mCO/cmꢀ1: 2094w,
2075w, 2032m, 2016s, 2004vs, 1962m, 1939m, 1883m.)
On column chromatographic separation of this solid, it
decomposed to give Os(H)2(CO)2(PPh3)2, 3, as a pale
yellow solid.
1
able position C. In contrast, the H NMR spectrum of
7c showed five singlets in the metal hydride region; the
two metal hydride resonances at )10.06 and )10.90 ppm
may be attributed to two geometrical isomers, in anal-
ogy to 7b. Additional resonances observed at )14.02,
)14.38 and )22.37 ppm may be attributed to decom-
position products of 7c on silica during TLC separation;
this sensitivity may also account for the isolation of
cluster 8 among the products (Table 2).
3: mCO/cmꢀ1: 2020s, 1990vs; mOsH/cmꢀ1: 1926m, 1871s;
1H NMR d 7.5–7.0 (m, 30H, Ph), )7.83 (t, 2H, OsH,
2JPH ¼ 22.68 Hz) (lit.:[7e] mCO/cmꢀ1: 2020s, 1990vs; mOsH
/
cmꢀ1: 1926m, 1871s; 1H NMR s 17.08 (2JPH ¼ 22.75
Our results are summarised in Scheme 1. Thus, we
have shown that nucleophilic substitution reactions of
Hz)); 31P{1H}NMR d 18.02s.
3.3. Reaction of 1 with AsPh3
Table 1
ꢀ
Selected bond lengths (A) and angles (°) for 7b and 7c
AsPh3 (41.0 mg, 134 lmol) was added to a solution of
1 (125 mg, 131 lmol) in dichloromethane (6 ml), fol-
lowed by trimethylamine-N-oxide dihydrate (20.0 mg,
180 lmol). Upon stirring, the reaction mixture turned
from yellow to orange. After one hour of stirring, the
solvent was removed in vacuo. TLC separation of the
residue with 1:1 (v/v) dichloromethane/hexane as eluant
afforded two major yellow bands which were charac-
terised as Os3(l-H)2(l-1-OC10H6)(CO)8(AsPh3), 4b
(Rf ¼ 0:61, 26.8 mg, 17%) and Os3(l-H)2(l-1-
OC10H6)(CO)7(AsPh3)2, 5b (Rf ¼ 0:39, 16.4 mg, 8%).
Bond parameter
7b
7c
2.8693(4)
Os(1)–Os(2)
Os(1)–Os(3)
2.8605(5)
2.8224(6)
2.8112(6)
2.131(7)
2.8003(3)
2.8046(4)
2.129(5)
Os(2)–Os(3)
Os(1)–O(1)
Os(2)–O(1)
2.123(6)
2.123(4)
Os(1)–As(4)/Sb(1)
Os(2)–As(5)/Sb(2)
\Os(2)Os(1)Os(3)
\Os(1)Os(2)Os(3)
\Os(1)Os(3)Os(2)
\Os(1)O(1)Os(2)
2.5055(11)
2.4932(11)
59.292(14)
59.680(14)
61.029(14)
84.5(2)
2.6531(5)
2.6454(6)
59.282(9)
59.135(9)
61.584(10)
84.87(16)

772
M.W. Lum, W.K. Leong / Inorganica Chimica Acta 357 (2004) 769–774
Table 2
Crystal data for 3, 4b, 5c, 7b, and 7c
Compound
6
7b
8c
10b
10c
Empirical formula
C
38H32O2OsP2
C36H23AsO9Os3
C53H38O8Os3Sb2
C54H38As2O9
Os3.CH2Cl2
1636.21
C54H38O9Os3
Sb2.CH2Cl2
1687.41
Formula weight
Temperature (K)
Crystal system
Space group
772.78
293(2)
1245.06
223(2)
1616.93
223(2)
223(2)
triclinic
173(2)
triclinic
orthorhombic
Pbca
monoclinic
P21=c
13.876
monoclinic
Cc
ꢁ
ꢁ
P1
P1
ꢀ
a (A)
17.9212(1)
18.2188(1)
19.7090(2)
90
39.6392(2)
22.5392(3)
23.5202(3)
90
12.1754(1)
13.4516(1)
18.7162(1)
102.981(1)
94.822(1)
115.845(1)
2629.69(3)
8004
13.1401(1)
14.6401(1)
14.7908(2)
93.692(1)
97.837(1)
105.685(1)
2698.46(5)
6330
ꢀ
b (A)
18.3063(2)
15.0157(2)
90
ꢀ
c (A)
a (°)
b (°)
c (°)
90
90
110.560(1)
90
105.499(1)
90
3
ꢀ
Volume (A )
6435.04(8)
6309
3571.45(6)
8192
20249.6(4)
8192
No. of reflections to determine
cell parameters
Z
8
4
16
2
2
Density (calculated) (g/cm3)
1.595
4.095
3056
2.316
11.619
2288
2.122
8.607
12000
2.066
8.636
1540
2.077
8.128
1570
Absorption coefficient (mmꢀ1
F(000)
)
Crystal size (mm3)
0.19 ꢁ 0.18 ꢁ 0.06 0.38 ꢁ 0.32 ꢁ 0.30 0.32 ꢁ 0.26 ꢁ 0.18 0.18 ꢁ 0.10 ꢁ 0.08 0.20 ꢁ 0.10 ꢁ 0.08
Theta range for data collection (°)
Reflections collected
Independent reflections
2.07–29.25
41803
8176
2.05–29.36
27661
8850
2.02–29.34
155213
44564
1.76–29.35
19664
12341
1.63–29.37
23023
12876
[Rint ¼ 0:0644]
0.745880 and
0.534168
[Rint ¼ 0:1183]
0.111081 and
0.056763
[Rint ¼ 0:1062]
0.210958 and
0.101915
[Rint ¼ 0:0463]
0.526897 and
0.332783
[Rint ¼ 0:0410]
0.563893 and
0.356326
Maximum and minimum transmission
Data/restraints/parameters
Goodness-of-fit on F 2
8176/0/426
1.079
8850/0/442
0.992
44564/26/1026
1.026
12341/0/643
1.032
12876/1/643
1.002
Final R indices [I > 2rðIÞ]
R1 ¼ 0:0409
wR2 ¼ 0:0624
R1 ¼ 0:0818
wR2 ¼ 0:0746
R1 ¼ 0:0572
wR2 ¼ 0:1664
R1 ¼ 0:0790
wR2 ¼ 0:1821
R1 ¼ 0:0789
wR2 ¼ 0:1590
R1 ¼ 0:1474
wR2 ¼ 0:1963
R1 ¼ 0:0576
wR2 ¼ 0:0997
R1 ¼ 0:1133
wR2 ¼ 0:1217
R1 ¼ 0:0410
wR2 ¼ 0:0840
R1 ¼ 0:0678
wR2 ¼ 0:0944
R indices (all data)
ꢀ3
ꢀ
Largest diff. peak and hole (e A
Absolute structure parameter
)
0.565 and )0.766 4.213 and )4.555 3.555 and )3.142 1.880 and )1.528 1.952 and )2.156
)0.026(7)
4b: mCO/cmꢀ1: 2096s, 2066m, 2055m, 2029s, 2014vs,
2010sh, 1990w, 1979w, 1973w, 1957m, 1948w; MS
(FAB): 1246 (calculated for Mþ, 1246).
5b: mCO/cmꢀ1: 2080w, 2023s, 2004vs, 1985w, 1945s.
1H NMR d 7.4–6.9 (m, aromatic), )9.82 (s, 1H,
OsHOs), )13.71 (s, 1H, OsHOs). MS (FAB): 1523
(calculated for Mþ, 1524).
A similar reaction with SbPh3 (41.0 mg, 11.6 lmol), 1
(24.4 mg, 25.7 lmol) and trimethylamine-N-oxide di-
hydrate (6.2 mg, 56 lmol) gave one major band upon
TLC separation, which was characterised as Os3(l-
H)2(l-1- OC10H6)(CO)7(SbPh3)2, 5c (Rf ¼ 0:49, 6.2 mg,
25%).
5c: mCO/cmꢀ1: 2078w, 2024s, 2005vs, 1949s, 1946s. 1H
NMR d 7.8–6.1 (m, aromatic), )9.91 (s, 1H, OsHOs)
and )14.32 (s, 1H, OsHOs). Anal. (Found) C, 39.81; H,
2.80. Calc. for C53H38O8Os3Sb2: C, 39.33; H, 2.35.
colour of the reaction mixture turned from yellow to
orange and upon further stirring an orange solid pre-
cipitated. The orange precipitate (B) was separated by
decantation. (Yield ¼ 24.2 mg.
m
CO/cmꢀ1
:
2113w,
2082sh, 2070sh, 2063br,vs, 2011br,vs, 1999br,vs.) An
attempt at chromatographic separation led to decom-
position. The supernatant was subjected to TLC sepa-
ration with 1:9 (v/v) dichloromethane/hexane as eluant
to afford Os3(l-H)(l-2-OC10H7)(CO)9(PPh3), 6a
(Rf ¼ 0:34, 5.1 mg, 11%) as the major product.
6a: mCO/cmꢀ1: 2095m, 2054s, 2017vs, 2010vs, 1990w,
1978m, 1972m, 1952m; 1H NMR d 7.5–7.4 (m, 22H,
2
aromatic), )12.44 (d, 1H, OsHOs, JPH ¼ 6 Hz);
31P{1H} NMR d 19.53s. MS (FAB): 1200 (calculated for
[M–CO]þ, 1202).
3.5. Reaction of 2 with AsPh3
3.4. Reaction of 2 with PPh3
AsPh3 (26.1 mg, 85.3 lmol) was added to a solution
of 2 (84.3 mg, 87.0 lmol) in dichloromethane (8 ml). The
mixture was allowed to stir at room temperature for
about 1 h to ensure dissolution before the addition of
trimethylamine-N-oxide dihydrate (20.0 mg, 180 lmol).
PPh3 (54.2 mg, 206 lmol) was added to a solution of
2 (44.9 mg, 46.4 lmol) in hexane (6 ml). The mixture
was allowed to stir at room temperature for 2d. The

M.W. Lum, W.K. Leong / Inorganica Chimica Acta 357 (2004) 769–774
773
Scheme 1.
The colour of the reaction mixture turned from yellow
to orange. After 1 h of stirring, the solvent was removed
in vacuo. TLC separation of the residue with di-
chloromethane/hexane (1:1, v/v) as eluant afforded two
major products, viz., Os3(l-H)(l-2-OC10H6)(CO)8 (As-
Ph3)2, 7b (Rf ¼ 0:53, 21.5 mg, 26%) as a dark orange
crystalline solid, and a yellow powder (C) which has
been tentatively formulated as Os3(l-H)(l-2-OC10H6)
(CO)9(AsPh3) (Rf ¼ 0:47, 8.1 mg, 10%).
7b: mCO/cmꢀ1: 2084m, 2073w, 2031w, 2008vs, 1972w,
1961w, 1942m; H NMR d 7.9–7.0 (m, 37H, aromatic),
1
)10.28 (s, 1H, OsHOs). MS (FAB): 1523 (calculated for
Mþ, 1523).
A similar reaction with SbPh3 (111.4 mg, 31.6 lmol),
2 (44.9 mg, 4.51 lmol) and trimethylamine-N-oxide di-
hydrate (6.2 mg, 56 lmol) gave, after TLC separation
(dichloromethane/hexane, 3:7, v/v), three major prod-
ucts, viz., Os3(l-H)(l-2-OC10H6)(CO)9(SbPh3), 6c
(Rf ¼ 0:62; ¼ 9:1 mg, 20%) as a bright yellow solid, the
known cluster Os3(CO)10(SbPh3)2, 8 (Rf ¼ 0:49, 6.9 mg,
15%) as a yellow crystalline solid, and Os3(l-H)
C: mCO/cmꢀ1: 2080s, 2071m, 2059w, 2031w, 2019sh,
2008vs, 2003s,sh, 1970m, 1939s. MS (FAB): 1244 (cal-
culated for for Mþ, 1246).

774
M.W. Lum, W.K. Leong / Inorganica Chimica Acta 357 (2004) 769–774
(l-2-OC10H6)(CO)8(SbPh3)2, 7c (Rf ¼ 0:45, 6.2 mg,
14%) as an orange crystalline solid.
Acknowledgements
6c: mCO/cmꢀ1: 2098w, 2059s, 2020vs, 2016sh, 1997w,
1986w, 1980w, 1949w. 1H NMR d 7.7–6.4 (m, aro-
matic), )11.23 (s, 1H, OsHOs). MS (FAB): 1320 (cal-
culated for Mþ, 1320).
This work was supported by the National University
of Singapore (Research Grant No. R-143-000-149-112)
and one of us (M.W.L.) thanks the University for a
Research Scholarship.
7c: mCO/cmꢀ1: 2086w, 2076m, 2033w, 2003vs, 1987m,
1966w, 1950w, 1930w. 1H NMR d 7.6–6.3 (m, aro-
matic), )10.06 (s, 1H, OsHOs). MS (FAB): 1617 (cal-
culated for [M–CO]þ, 1618).
References
8: mCO/cmꢀ1: 2087w, 2033m, 2017m, 2005vs, 1973w,
1961w, 1949w. MS (FAB): 1556 (calculated for Mþ,
1558).
[1] M.W. Lum, W.K. Leong, J. Chem. Soc., Dalton Trans. (2001) 2476.
[2] B. Bergman, R. Holmquist, R. Smith, E. Rosenberg, J. Ciurash,
K.I. Hardcastle, M. Visi, J. Am. Chem. Soc. 120 (1998) 12818;
M.J. Abedin, B. Bergman, R. Holmquist, R. Smith, E. Rosenberg,
J. Ciurash, K.I. Hardcastle, J. Roe, V. Vazquez, C. Roe, S. Kabir,
B. Roy, S. Alam, K.A. Azam, Coord. Chem. Rev. 190-2 (1999)
975, and references therein.
3.6. Crystal structure determinations
[3] H. Chen, B.F.G. Johnson, J. Lewis, Organometallics 8 (1989) 2965.
[4] J.P.H. Charmant, H.A.A. Dickson, N.J. Grist, J.B. Keister,
S.A.R. Knox, D.A.V. Morton, A.G. Orpen, J.M. Vinas, J. Chem.
Soc., Chem. Commun. (1991) 1393;
Crystals were grown by slow cooling from dichlo-
romethane/hexane solutions and mounted on quartz
fibres. X-ray data were collected on a Bruker AXS
APEX system, using Mo Ka radiation, with the
SMART suite of programs [11]. Data were corrected
for Lorentz and polarisation effects with SAINT [12],
and for absorption effects with SADABS [13]. The final
unit cell parameters were obtained by least squares on
a number of strong reflections. Structural solution and
refinement were carried out with the SHELXTL suite of
programs [14].
J.P.H. Charmant, H.A.A. Dickson, N.J. Grist, S.A.R. Knox, A.G.
Orpen, K. Saynor, J.M. Vinas, J. Organomet. Chem. 565 (1998) 141.
[5] K.A. Azam, A.J. Deeming, R.E. Kimber, J. Chem. Soc., Dalton
Trans. (1976) 1853.
[6] M.W. Lum, W.K. Leong, unpublished results.
[7] (a) F. LÕEplattenier, F. Calderazzo, Inorg. Chem. 6 (1967) 2092;
(b) F. LÕEplattenier, F. Calderazzo, Inorg. Chem. 7 (1968) 1290;
(c) K.R. Laing, W.R. Roper, J. Chem. Soc. (A) (1969) 1889;
(d) N. Ahmad, S.D. Robinson, M.F. Uttley, J. Chem. Soc.,
Dalton Trans. (1972) 843;
The structures were solved by direct methods to lo-
cate the heavy atoms, followed by difference maps for
the light, non-hydrogen atoms. Organic H atoms were
generally placed in calculated positions and given iso-
tropic thermal parameters at 1.5 times that of the C
atoms to which they are attached. The metal hydride
positions were either located by low angle difference
maps (3, 4b, 7b and 7c) and their positions refined but
with the isotropic thermal parameters fixed, or were
placed in calculated positions with XHYDEX (5c) [15].
All non-hydrogen atoms were given anisotropic thermal
parameters in the final models, except for 8c, in which
the carbon atoms were also given isotropic thermal pa-
rameters, and vibration restraints were placed on all Os–
C–O bonds.
(e) N. Ahmad, J.J. Levison, S.D. Robinson, M.F. Uttley, Inorg.
Synth. 15 (1974) 55;
(f) K.S. Coleman, J.H. Holloway, E.G. Hope, J. Langer, J. Chem.
Soc., Dalton Trans. (1997) 4555.
[8] G.J. Kubas, in: J.P. Fackler Jr. (Ed.), Metal Dihydrogen and r-
Bond Complexes, Kluwer, New York, 2001.
[9] J. Banford, M.J. Mays, P.R. Raithby, J. Chem. Soc., Dalton
Trans. (1985) 1355;
N.V. Podberezskaya, V.A. Maksakov, L.K. Kedrova, E.D.
Korniets, S.P. Gubin, Koord. Khim. 10 (1984) 919.
[10] E.J. Ditzel, M.P. Gomez-Sal, B.F.G. Johnson, J. Lewis, P.R.
Raithby, J. Chem. Soc., Dalton Trans. (1987) 1623.
[11] SMART version 5.628, Bruker AXS Inc., Madison, Wisconsin,
USA, 2001.
[12] SAINT+ version 6.22a, Bruker AXS Inc., Madison, Wisconsin,
USA, 2001.
€
[13] G.M. Sheldrick, SADABS, University of Gottingen, 1996.
[14] SHELXTL, version 5.03, Siemens Energy and Automation Inc.,
Madison, WI, 1996.
There was a dichloromethane solvent molecule found
in 5c, modelled as being present with an occupancy
factor of 0.5.
[15] A.G. Orpen, XHYDEX: A Program for Locating Hydrides in Metal
Complexes, School of Chemistry, University of Bristol, UK, 1997.