Syntheses and structural studies of five- and six-coordinate o-halophenyl derivatives of ruthenium(II) and osmium(II)

Article abstract of DOI:10.1016/S0022-328X(00)00170-4

Reaction between MHCl(CO)(PPh₃)₃ (M = Ru, Os) and the o-halophenyl mercury compounds, Hg(C₆H₄X-2)₂ (X = Cl, Br, I) gives the five co-ordinate complexes, M(C₆H₄X-2)Cl(CO)(PPh

Full text of DOI:10.1016/S0022-328X(00)00170-4

www.elsevier.nl/locate/jorganchem
Journal of Organometallic Chemistry 607 (2000) 27–40
Syntheses and structural studies of five- and six-coordinate
o-halophenyl derivatives of ruthenium(II) and osmium(II)
Clifton E.F. Rickard, Warren R. Roper* 1, Scott D. Woodgate, L. James Wright* 2
Department of Chemistry, The Uni6ersity of Auckland, Pri6ate Bag 92019, Auckland, New Zealand
Received 4 February 2000; received in revised form 3 March 2000
Dedicated to Professor Martin A. Bennett on the occasion of his retirement from the Research School of Chemistry, The Australian National
University.
Abstract
Reaction between MHCl(CO)(PPh3)3 (M=Ru, Os) and the o-halophenyl mercury compounds, Hg(C6H4X-2)2 (X=Cl, Br, I)
gives the five co-ordinate complexes, M(C6H4X-2)Cl(CO)(PPh3)2 (1a M=Ru, X=Cl; 1b M=Ru, X=Br; 2a M=Os, X=Cl;
2b M=Os, X=Br; 2c M=Os, X=I). In these complexes there is a significant bonding interaction between the coordinatively
unsaturated metal centre and the o-halo-substituent on the s-bound phenyl group as revealed by crystal structure determinations
of 2a, 2b, and 2c. Each of the five-coordinate complexes readily adds CO forming the corresponding six-coordinate dicarbonyl
complexes, M(C6H4X-2)Cl(CO)2(PPh3)2 (5a M=Ru, X=Cl; 5b M=Ru, X=Br; 6a M=Os, X=Cl; 6b M=Os, X=Br; 6c
M=Os, X=I). Crystal structure determination of 6a confirms regular octahedral geometry for these six-coordinate complexes
with no interaction between the metal centre and the o-halo-substituent on the s-bound phenyl group. The complexes 1a, b, 2a–c,
5a, b, 6a–c, are potentially precursors of benzyne complexes through reduction (removal of ClX) but all attempts at reduction
were unsuccessful. The related thiocarbonyl complexes, Os(C6H4X-2)Cl(CS)(PPh3)2 (7a X=Cl; 7b X=Br) and Os(C6H4X-
2)Cl(CO)(CS)(PPh3)2 (8a X=Cl; 8b X=Br), have been prepared similarly beginning with OsHCl(CS)(PPh3)3. The crystal
structure of 8a has been determined. Both 8a and 8b undergo a slow migratory-insertion reaction upon heating to yield the
corresponding h2-thioacyl complexes, Os(h2-C[S]C6H4X-2)Cl(CO)(PPh3)2 (9a X=Cl; 9b X=Br), the crystal structures of both of
which have been determined. Once the o-halophenyl group is no longer directly bonded to the metal, as in 9a and 9b, normal
reactivity returns to the o-halo substituent and 9b undergoes lithium–bromine exchange when treated with n-butyllithium and the
resulting lithiated material, when treated with SnnBu3Cl, gives Os(h2-C[S]C6H4SnnBu3-2)Cl(CO)(PPh3)2 (10). © 2000 Elsevier
Science S.A. All rights reserved.
Keywords: Ruthenium; Organometallic complexes; Osmium
1. Introduction
established that a convenient route to coordinatively
unsaturated s-aryl derivatives of ruthenium and os-
mium, M(Ar)Cl(CO)(PPh3)2 involves treatment of MH-
Cl(CO)(PPh3)3 with HgAr2 [4]. This reaction is general
and aryl groups bearing various functionalities have
been transferred to ruthenium or osmium. Where the
Many examples of o-halophenyl derivatives of both
main group elements [1] and transition metals [2] (see
Fig. 1) are known. One of the main reasons for contin-
uing interest in this class of compounds is that the
transition metal derivatives are potential precursors of
transition metal benzyne complexes as has been demon-
strated by the work of the dedicatee of this paper,
Professor M.A. Bennett and his coworkers [3]. We have
1 *Corresponding author. Tel.: +64-9-3737999, ext. 8320; fax:
+64-9-3737422; e-mail: w.roper@auckland.ac.nz
2 *Corresponding author.
Fig. 1. o-Halophenyl complexes of ruthenium(II) and osmium(II).
0022-328X/00/$ - see front matter © 2000 Elsevier Science S.A. All rights reserved.
PII: S0022-328X(00)00170-4

28
C.E.F. Rickard et al. / Journal of Organometallic Chemistry 607 (2000) 27–40
2. Results and discussion
2.1. Syntheses of fi6e and six coordinate o-halophenyl
complexes of ruthenium(II) and osmium(II)
The five coordinate o-halophenyl complexes,
M(C6H4X-2)Cl(CO)(PPh3)2 (1a M=Ru, X=Cl; 1b
M=Ru, X=Br; 2a M=Os, X=Cl; 2b M=Os, X=
Br; 2c M=Os, X=I), were prepared by treatment of
MHCl(CO)(PPh3)3 with Hg(C6H4X-2)2 according to
Scheme 1. In the case of X=Br, it proved to be more
convenient, not to isolate the five coordinate complex
directly, but rather to add sodium acetate and isolate
the saturated, h2-acetato-derivatives, M(C6H4Br-2)(h2-
O2CMe)(CO)(PPh3)2 (3 M=Ru; 4 M=Os). Com-
pounds 3 and 4 are readily converted to 1b and 2b,
respectively, by treatment with HCl. Addition of CO
rapidly converts 1a–b, 2a–c to the corresponding
colourless, six coordinate, dicarbonyl complexes, 5a–b,
6a–c. IR, H- and 13C-NMR data for these and other
1
Scheme 1. Synthesis and reactions of the carbonyl-containing o-
halophenyl complexes, M(C6H4X-2)Cl(CO)(PPh3)2.
new compounds reported in this paper are collected in
Tables 1–3. As a typical example, the data for 2a is
discussed below. The IR spectrum of complex 2a shows
w(CO) at 1912 cm−1, similar to the position observed
functional group is in the ortho-position and contains a
potential donor atom there is a chelating interaction
with the metal centre, as observed for example in the
o-nitrophenyl derivatives [5]. The availability of HgAr2
where Ar=o-halophenyl [6], presented the possibility
of forming the coordinatively unsaturated o-halophenyl
complexes of ruthenium and osmium. These com-
pounds were of interest both as potential benzyne com-
plex precursors and because of possible interaction of
the halo-substituent with the metal centre. In most of
the previously reported o-halophenyl complexes the
metal is coordinatively saturated or has no effective
vacant coordination site, e.g. Ni(II), Pt(II), and in these
cases there is no structural evidence for a bonding
interaction between the o-halo substituent and the
metal.
1
for Os(C6H4CH3-2)Cl(CO)(PPh3)2 [4b]. The H-NMR
spectrum reveals signals due to all four of the aromatic
ring protons in the region expected. Apparent doublets
at 5.60 (3JHH=7.3 Hz) and 6.14 ppm (3JHH=6.9 Hz)
are assigned to the protons at ring positions 3 and 6
(see Fig. 1 for numbering), respectively. Apparent
triplets at 6.19 (3JHH=7.3 Hz) and 6.41 ppm (3JHH
=
7.5 Hz) are assigned to protons at ring positions 4 and
5. The 13C-NMR spectrum shows a triplet for the
carbonyl resonance at 179.38 ppm (2JCP=11.0 Hz), due
to coupling to the two identical phosphorus nuclei. The
unsubstituted carbons of the chlorophenyl ring are
observed as singlets at 121.4, 123.86, 127.93, and 138.43
ppm. The quaternary ring carbons were not observed.
The colour of complexes 1a–b, 2a–c are yellow–or-
ange. In contrast, coordinatively unsaturated complexes
of the type M(Ar)Cl(CO)(PPh3)2 which have been pre-
pared previously are usually dark-red in colour [4]. This
difference in colour could be indicative of an interac-
tion between the halo-substituent on the aryl ligand,
and the metal centre. To examine this possibility, single
crystal X-ray structure determinations for 2a–c were
obtained. In addition, the crystal structure of 6a was
obtained to provide information on the structure of a
complex where no interaction with the o-halo-sub-
stituent is possible.
In this paper we report (i) the synthesis of a set of
five coordinate complexes, M(C6H4X-2)Cl(CO)(PPh3)2
and the corresponding set of six coordinate complexes,
M(C6H4X-2)Cl(CO)2(PPh3)2; (ii) comparitive structural
studies of examples from both sets which reveal a
significant bonding interaction between the halo-sub-
stituent and the metal centre in the five coordinate
compounds; (iii) the synthesis of thiocarbonyl-contain-
ing osmium analogues which undergo migratory inser-
tion reactions forming the corresponding h2-thioacyl
derivatives, Os(h2-C[S]C6H4X-2)Cl(CO)(PPh3)2; (iv) in-
vestigations of the reduction of these o-halophenyl
complexes to benzyne complexes; and (v) the lithiation
of Os(h2-C[S]C6H4X-2)Cl(CO)(PPh3)2 and subsequent
2.2. Crystal structure determinations of 2a–c, and 6a
Details of the crystal structure determinations for
2a–c and 6a, and for the other crystal structures re-
ported in this paper, are collected in Table 4. Selected
stannylation
(PPh3)2.
to
Os(h2-C[S]C6H4SnBun3-2)Cl(CO)-

C.E.F. Rickard et al. / Journal of Organometallic Chemistry 607 (2000) 27–40
29
bond distances and angles for 2a–c and 6a are given in
Tables 5–8, respectively. Since 2a–c are isostructural,
only one ORTEP diagram is shown, that of 2a in Fig. 2,
and the molecular geometry of 6a is given in Fig. 3.
In all these structures, the two triphenylphosphine
ligands are located mutually trans. The osmium-bound
chloride is trans to the C6H4X-2 ring with the bond
is also made with the dicarbonyl analogue 6a. For 2a
the distance between the o-chloro substituent on the
,
phenyl ring and osmium (OsꢀCl(2)) is 2.826(4) A. This
is outside the range of previously reported OsꢀCl bond
distances since a search of the CCD shows that re-
,
ported OsꢀCl distances range from 2.178 to 2.759 A
,
(560 observations, average 2.380 A, standard deviation
,
0.065 A). Nevertheless, a bonding interaction must be
,
distance, OsꢀCl(1) being 2.459(5) A in 2a. A conspicu-
present to account for the significant distortions from
idealised geometries that displace the halogen towards
the osmium atom. The structural data for 2b and 2c
show the same distortions involving the o-halophenyl
group with the distance between the o-bromo sub-
stituent on the phenyl ring and osmium being 2.8323(8)
ous feature apparent in Fig. 2 is that for the structures
of 2a–c the o-halophenyl group lies in the plane con-
taining Os, C(1), C(2), and Cl(1), with the ortho-halo-
gen substituent making a close approach to osmium.
This interaction is accompanied by both a tilting of the
ring within the equatorial plane and a reduction of the
angle C(2)ꢀC(3)ꢀX from the idealised 120°. These dis-
tortions are summarised in Fig. 4 where a comparison
,
A and the corresponding OsꢀI distance being 2.9335(6)
,
A. This OsꢀI distance is only slightly outside the range
,
2.61–2.87 A reported in the CCD for osmiumꢀiodide
,
bonds (106 observations, average 2.75 A, standard devi-
ation 0.095 A).
,
Instances of haloarenes functioning as ligands to-
wards transition metals are well known. Examples are
provided by the structurally characterised ortho-
diiodobenzene complex of iridium, [Ir(h2-I2C6H4)-
H2(PPh3)2]PF6 [7] and the halobenzene complexes of
platinum, trans-[Pt(h1-XPh)H(PiPr3)2]+ (X=I, Br) [8].
The dicarbonyl complex, 6a, has an almost regular
octahedral geometry about osmium (see Fig. 3). Intro-
duction of CO saturates the metal centre and a bonding
interaction between the o-chloro substituent and the
osmium is no longer possible. As a consequence, steric
effects dominate and the o-chlorophenyl ring twists out
of the equatorial plane by 28°. Examination of Fig. 4
shows that q1 is now greater than 120° whereas for
2a–c the corresponding angle is always considerably
Table 1
IR data for o-halophenyl ruthenium(II) and osmium(II) complexes
Complex
w(CO)
Other bands
(cm−1
(cm−1
)
)
Ru(C6H4Cl-2)Cl(CO)(PPh3)2 (1a) 1927, 1916, 1798, 1760, 1601,
1921
1310, 1270
1586, 581
1651, 1572, 1259,
1224
1587, 1541, 645
1710, 1594, 953,
609
1560, 1526, 753,
743, 668, 595,
543, 510
Ru(C6H4Br-2)Cl(CO)(PPh3)2 (1b) 1915
Os(C6H4Cl-2)Cl(CO)(PPh3)2 (2a)
1912
Os(C6H4Br-2)Cl(CO)(PPh3)2 (2b)
Os(C6H4I-2)Cl(CO)(PPh3)2 (2c)
1911
1902
Ru(C6H4Br-2)(h2-O2CCH3)(CO)
(PPh3)2 (3)
1924
1914
Os(C6H4Br-2)(h2-O2CCH3)(CO)
(PPh3)2 (4)
Ru(C6H4Cl-2)Cl(CO)2(PPh3)2 (5a) 2032, 1957 1654, 1400, 800,
1564, 1520, 952,
606, 557
,
less than 120°. The OsꢀC(3) distance of 2.169(6) A is
longer than the corresponding distances found for com-
668
Ru(C6H4Br-2)Cl(CO)2(PPh3)2 (5b) 2043, 1961 1608, 1591
Os(C6H4Cl-2)Cl(CO)2(PPh3)2 (6a) 2018, 1941 1654, 1570, 1405,
668
pounds 2a–c (see Fig. 4).
2.3. Syntheses of fi6e and six coordinate o-halophenyl
complexes of osmium(II) incorporating thiocarbonyl
ligands
Os(C6H4Br-2)Cl(CO)2(PPh3)2 (6b) 2017, 1957, 1587, 1573, 1312,
1940
846, 620, 598
Os(C6H4I-2)Cl(CO)2(PPh3)2 (6c)
Os(C6H4Cl-2)Cl(CS)(PPh3)2 (7a)
2022, 1939 1716, 1573, 1541,
1313, 847, 663,
597
The five coordinate, thiocarbonyl-containing, o-
halophenyl complexes, Os(C6H4X-2)Cl(CS)(PPh3)2 (7a
X=Cl; 7b X=Br), were prepared by treatment of
OsHCl(CS)(PPh3)3 with Hg(C6H4X-2)2 according to
Scheme 2. Both 7a and 7b are bright yellow in colour
and show strong thiocarbonyl absorptions in the IR
spectrum at 1307 cm−1 for 7a and at 1306 cm−1 for 7b
(see Tables 1–3 for further spectroscopic data). Addi-
tion of CO to 7a and 7b, in a rapid reaction, gives the
1654, 1568, 1307
w(CS), 647
Os(C6H4Br-2)Cl(CS)(PPh3)2 (7b)
1654, 1306 w(CS)
Os(C6H4Cl-2)Cl(CS)(CO)(PPh3)2
(8a)
Os(C6H4Br-2)Cl(CS)(CO)(PPh3)2
2010
2021
1291 w(CS), 668,
503
1577, 1291, 813,
704, 668, 592
1482, 1295, 1236,
668
1574, 1296, 1263,
810, 635, 618,
592, 577
1573, 1291, 1261,
824, 596
(8b)
Os(h2-C[S]C6H4Cl-2)Cl(CO)(PPh3)2 1901
(9a)
Os(h2-C[S]C6H4Br-2)Cl(CO)(PPh3)2 1898
(9b)
colourless,
coordinatively
saturated
complexes,
Os(C6H4X-2)Cl(CO)(CS)(PPh3)2 (8a X=Cl; 8b X=
Br). The crystal structure of 8a has been determined
(see Fig. 5 for molecular geometry and Table 9 for
selected bond distances and angles). The structure re-
Os(h2-C[S]C6H4SnnBu3-2)Cl(CO)
(PPh3)2 (10)
1900

30
C.E.F. Rickard et al. / Journal of Organometallic Chemistry 607 (2000) 27–40
Table 2
1H-NMR data for o-halophenyl ruthenium(II) and osmium(II) complexes
Complex
Chemical shift (ppm)/coupling constant (Hz)
Ru(C6H4Cl-2)Cl(CO)(PPh3)2 (1a)
Ru(C6H4Br-2)Cl(CO)(PPh3)2 (1b)
Os(C6H4Cl-2)Cl(CO)(PPh3)2 (2a)
Os(C6H4Br-2)Cl(CO)(PPh3)2 (2b)
Os(C6H4I-2)Cl(CO)(PPh3)2 (2c)
Ru(C6H4Br-2)(h2-O2CCH3)(CO)(PPh3)2 (3)
Os(C6H4Br-2)(h2-O2CCH3)(CO)(PPh3)2 (4)
Ru(C6H4Cl-2)Cl(CO)2(PPh3)2 (5a)
Ru(C6H4Br-2)Cl(CO)2(PPh3)2 (5b)
Os(C6H4Cl-2)Cl(CO)2(PPh3)2 (6a)
Os(C6H4Br-2)Cl(CO)2(PPh3)2 (6b)
5.62 (d, 1H, C6H4Cl, 3JHH=6.8); 6.15 (t, 1H C6H4Cl, 3JHH=6.5); 6.27 (d, 1H, C6H4Cl,
3JHH=7.2); 6.48 (t, 1H, C6H4Cl, 3JHH=7.4); 7.25–7.70 (m, 30H, PPh3).
5.46 (d, 1H, C6H4Br, 3JHH=7.4); 6.07 (t, 1H, C6H4Br, 3JHH=7.1); 6.34–6.42 (m, 2H,
C6H4Br); 7.20–7.78 (m, 30H, PPh3).
5.60 (d, 1H, C6H4Cl, 3JHH=7.3); 6.14 (d, 1H, C6H4Cl, 3JHH=6.9); 6.19 (t, 1H, C6H4Cl,
3JHH=7.3); 6.41 (t, 1H, C6H4Cl, 3JHH=7.5); 7.24–7.61 (m, 30H, PPh3)
5.40 (d, 1H, C6H4Br, 3JHH=7.4); 6.12 (t, 1H, C6H4Br, 3JHH=7.1); 6.22 (d, 1H, C6H4Br,
3JHH=7.4); 6.35 (t, 1H, C6H4Br, 3JHH=7.4); 7.26–7.70 (30H, m, PPh3).
5.22 (d, 1H, C6H4I, 3JHH=7.3); 5.99 (t, 1H C6H4I, 3JHH=7.2); 6.19 (t, 1H C6H4I,
3JHH=7.3); 6.38 (d, 1H, C6H4I, 3JHH=7.8); 6.95–7.70 (m, 30H, PPh3).
0.62 (s, 3H, CH3CO2); 6.27 (t, 1H, C6H4Br, 3JHH=6.9); 6.55 (t, 1H, C6H4Br, 3JHH=6.8);
6.72 (d, 1H, C6H4Br, 2JHH=6.6); 7.61 (t, d, C6H4Br, 3JHH=7.0); 7.17–7.43 (30H, m, PPh3).
0.53 (s, 3H, CH3CO2); 6.24 (t, 1H, C6H4Br, 3JHH=7.0); 6.55 (t, 1H, C6H4Br 3JHH=6.9,
4JHH=1.1); 6.75 (d, 1H, C6H4Br, 3JHH=7.9, 4JHH=1.4); 7.28–7.46 (30H, m, PPh3).
6.34 (t, 1H, C6H4Cl, 3JHH=7.0); 6.69 (t, 1H, C6H4Cl, 3JHH=7.0); 6.84 (d, 1H, C6H4Cl,
3JHH=7.8); 7.18 (d, 1H, C6H4Cl, 3JHH=7.8); 7.17–7.46 (m, 30H, PPh3).
6.42 (t, 1H, C6H4Br, 3JHH=7.0); 6.54 (t, 1H, C6H4Br, 3JHH=7.6); 6.81 (dd, 1H, C6H4Br,
3JHH=7.8, 4JHH=1.6); 6.88 (d, 1H, C6H4Br, 3JHH=7.8); 7.24–7.48 (m, 30H, PPh3).
6.36 (t, 1H, C6H4Cl, 3JHH=7.1); 6.68 (t, 1H, C6H4Cl, 3JHH=7.1); 6.83 (d, 1H, C6H4Cl,
3JHH=7.7); 7.15 (d, 1H, C6H4Cl, 2JHH=7.7); 7.14–7.45 (m, 30H, PPh3).
6.35 (td, 1H, C6H4Br, 3JHH=7.1, 4JHH=1.26); 6.58 (t, 1H, C6H4Br, 3JHH=7.4); 7.05 (d,
1H, C6H4Br, 3JHH=7.8); 7.27 (dd, 1H, C6H4Br, 3JHH=7.7, 4JHH=1.7); 7.30–7.53 (m, 30H,
PPh3).
Os(C6H4I-2)Cl(CO)2(PPh3)2 (6c)
Os(C6H4Cl-2)Cl(CS)(PPh3)2 (7a)
6.37 (m, 2H, C6H4I); 7.03 (m, 2H, C6H4I); 7.24–7.52 (m, 30H, PPh3).
5.90 (dd, 1H, C6H4Cl, 3JHH=7.2, 4JHH=1.2); 6.27 (dd, 1H, C6H4Cl, 3JHH=7.8,
4JHH=1.2); 6.37 (td, 1H, C6H4Cl, 3JHH=7.4, 4JHH=1.2; 6.50 (bt, 1H, C6H4Cl, 3JHH=6.5);
7.02–7.65 (30H, m, PPh3).
Os(C6H4Br-2)Cl(CS)(PPh3)2 (7b)
5.69 (d, 1H, C6H4Br, 3JHH=7.2); 6.29 (t, 1H, C6H4Br, 3JHH=6.3); 6.40 (m, 2H, C6H4Br);
7.02–7.54 (30H, m, PPh3).
Os(C6H4Cl-2)Cl(CS)(CO)(PPh3)2 (8a)
6.33 (td, 1H, C6H4Cl, 3JHH=7.4, 4JHH=1.3); 6.68 (t, 1H, C6H4Cl, 3JHH=6.6); 6.83 (dd,
1H, C6H4Cl, 3JHH=7.9, 4JHH=1.8); 7.00 (dd, 1H, C6H4Cl, 3JHH=7.8, 4JHH=1.2);
6.37–6.44 (m, 2H, C6H4Cl); 7.25–7.57 (30H, m, PPh3).
Os(C6H4Br-2)Cl(CS)(CO)(PPh3)2 (8b)
6.31 (td, 1H, C6H4Br, 3JHH=7.4, 4JHH=1.3); 6.57 (t, 1H, C6H4Br, 3JHH=6.6); 6.93 (dd,
1H, C6H4Br, 3JHH=7.9, 4JHH=1.8); 7.04 (dd, 1H, C6H4Br, 3JHH=7.8, 4JHH=1.2);
6.37–6.44 (m, 2H, C6H4Br); 7.22–7.69 (30H, m, PPh3).
Os(h2-C[S]C6H4Cl-2)Cl(CO)(PPh3)2 (9a)
Os(h2-C[S]C6H4Br-2)Cl(CO)(PPh3)2 (9b)
6.71 (t, 1H, C6H4Cl, 3JHH=7.3, 4JHH=0.8); 6.96 (d, 1H, C6H4Cl, 3JHH=7.5); 7.21–7.72 (m,
2H, C6H4Cl, 30H, PPh3).
6.76 (t, 3JHH=7.2, 1H, C6H4Br); 7.11 (t, 1H, C6H4Br, 3JHH=7.2); 7.15–7.88 (m, 32H,
C6H4Br, PPh3).
Os(h2-C[S]C6H4SnnBu3-2)Cl(CO)(PPh3)2 (10) 0.76 (t, 2H, CH3CH2CH2CH2, 3JHH=8.1); 0.83 (m, 3H, CH3CH2CH2CH2, 3JHH=7.2);
1.12–1.21 (m, 2H, CH3CH2CH2CH2); 1.27–1.34 (2H, CH3CH2CH2CH2); 6.75 (t, 3JHH=7.2,
1H, C6H4); 6.83 (t, 1H, C6H4 3JHH=7.8); 7.20–7.64 (m, C6H4, PPh3)
veals that 8a is very similar to 6a, with the thiocarbonyl
ligand and the o-chlorophenyl ligands cis to one
another.
tion in the phenyl ring slows migration in these exam-
ples, it remains to be seen whether or not this is a
general observation. Crystal structure determinations
on both 9a and 9b have been obtained. The compounds
are isostructural and a molecular geometry diagram for
9a appears in Fig. 6 and selected bond distances and
angles for 9a and 9b appear in Tables 10 and 11,
respectively. The structures confirm the h2-thioacyl ge-
ometry and bond distances and angles are as expected.
The o-halophenyl ligands lie in the equatorial plane of
the complexes and the halogen substituents, through
being more remote from the metal centre, are less
encumbered sterically than the same substituents in 8a
and 8a (see Section 2.7).
2.4. Migratory insertion reactions of 8a and 8b
Aryl, thiocarbonyl complexes of osmium that are
closely related to 8a and 8b, readily undergo migratory
insertion to form h2-thioacyl complexes [9]. For
Os(C6H4Me-4)Cl(CO)(CS)(PPh3)2 this rearrangement
occurs rapidly at room temperature (r.t.). In contrast,
for 8a and 8b migratory insertion occurs only on heat-
ing under reflux in toluene to give the red–purple
h2-thioacyl complexes, Os(h2-C[S]C6H4X-2)Cl(CO)-
(PPh3)2 (9a X=Cl; 9b X=Br). While halogen substitu-

C.E.F. Rickard et al. / Journal of Organometallic Chemistry 607 (2000) 27–40
31
Table 3
13C-NMR data for o-halophenyl ruthenium(II) and osmium(II) complexes
Complex
Chemical shift (ppm)/Coupling constant (Hz)
Ru(C6H4Cl-2)Cl(CO)(PPh3)2 (1a)
122.22 (s, C6H4Cl); 123.74 (s, C6H4Cl); 127.84 (s, C6H4Cl); 139.02 (s, C6H4Cl); 155.2 (t, C6H4Cl Cq,
2JCP=9.0); 207.7 (CO, t, 2JCP=17.6); 128.25 (t% [10], PPh3 ortho, 2,4JCP=10.1); 130.17 (s, PPh3
para); 132.65, (t%, PPh3 ipso, 1,3JCP=44.3); 134.75 (t%, PPh3 meta, 3,5JCP=10.1).
122.11 (s, C6H4Br); 125.16 (s, C6H4Br); 139.20 (s, C6H4Br); 127.73 (t%, PPh3 ortho, 2,4JCP=9.1);
129.54 (s, PPh3 para); 132.59 (t%, PPh3 ipso, 1,3JCP=45.3); 134.19 (t%, PPh3 meta, 3,5JCP=11.1).
121.4 (s, C6H4Cl); 123.86 (s, C6H4Cl); 127.93 (s, C6H4Cl); 138.43 (s, C6H4Cl); 179.38 (t, CO,
2JCP=11.0); 128.28 (t%, PPh3 ortho, 2,4JCP=9.1); 130.25 (s, PPh3 para); 132.36 (t%, PPh3 ipso,
1,3JCP=51.3); 134.84 (t%, PPh3 meta, 3,5JCP=10.1).
Ru(C6H4Br-2)Cl(CO)(PPh3)2 (1b)
Os(C6H4Cl-2)Cl(CO)(PPh3)2 (2a)
Os(C6H4Br-2)Cl(CO)(PPh3)2 (2b)
Os(C6H4I-2)Cl(CO)(PPh3)2 (2c)
121.10 (s, C6H4Br); 125.22 (s, C6H4Br); 127.88 (s, C6H4Br); 131.63 (s, C6H4Br Cq); 138.57 (s,
C6H4Br); 179.29 (t, 2JCP=11.0, CO); 127.71 (t%, PPh3 ortho, 2,4JCP=9.1), 129.60 (s, PPh3 para);
132.30 (t, PPh3 ipso, 1,3JCP=44.3); 134.27 (t%, PPh3 meta, 3,5JCP=11.1).
109.32 (s, Cq); 121.99 (s, C6H4I); 128.79 (s, C6H4I); 129.55 (s, C6H4I); 140.54 (s, C6H4I); 134.77 (t,
C6H4I Cq, 2JCP=5.0); 180.70 (t, CO, 2JCP=11.0); 128.17 (t%, PPh3 ortho, 2,4JCP=9.1); 130.0 (s,
PPh3 para); 133.65 (t% PPh3 ipso, 1,3JCP=50.3); 134.77 (t%, PPh3 meta, 3,5JCP=10.1).
22.64 (s, CH3CO2); 122.41 (s, C6H4Br); 122.75 (s, C6H4Br); 132.68 (s, C6H4Br); 162.68 (t, C6H4Br
Cq, 2JCP=13.9); 183.6 (s, CH3CO2); 208.71 (CO, t, 2JCP=14.1); 128.18 (t%, PPh3 ortho, 2,4JCP=9.1);
130.00 (s, PPh3); 131.37 (t%, PPh3 ipso, 1,3JCP=43.3); 134.89 (t%, PPh3 meta, 3,5JCP=11.1).
23.20 (s, CH3CO2); 121.29 (s, C6H4Br); 122.11 (s, C6H4Br); 131.86 (s, C6H4Br); 133.91 (s, C6H4Br);
142.34 (s, C6H4Br Cq); 142.60 (t, C6H4Br Cq, 2JCP=13.7); 184.18 (t, CO, 2JCP=10.1); 184.28 (s,
CH3CO2); 127.69 (t%, PPh3 ortho, 2,4JCP=9.1); 129.65 (s, PPh3 para); 130.44 (t%, PPh3 ipso,
1,3JCP=49.3); 134.51 (t%, PPh3 meta, 3,5JCP=10.1).
Ru(C6H4Br-2)(h2-O2CCH3)(CO)
(PPh3)2 (3)
Os(C6H4Br-2)(h2-O2CCH3)(CO)
(PPh3)2 (4)
Ru(C6H4Cl-2)Cl(CO)2(PPh3)2 (5a)
124.56 (s, C6H4Cl); 125.28 (s, C6H4Cl); 127.83 (s, C6H4Cl); 144.31 (s, C6H4Cl); 158.81 (t,
2JCP=11.0); 194.66 (t, CO, 2JCP=13.0); 199.33 (t, CO, 2JCP=13.0); 128.08 (t%, PPh3 ortho,
2,4JCP=9.1); 130.50 (s, PPh3 para); 132.32 (t%, PPh3 ipso, 1,3JCP=46.3); 134.96 (t%, PPh3 meta,
3,5JCP=10.1).
Ru(C6H4Br-2)Cl(CO)2(PPh3)2 (5b)
Os(C6H4Cl-2)Cl(CO)2(PPh3)2 (6a)
124.11 (s, C6H4Br); 125.11 (s, C6H4Br); 131.41 (s, C6H4Br); 143.64 (s, C6H4Br); 195.90 (t, CO,
2JCP=17.0); 202.78 (t, CO, 2JCP=17.0); 128.12 (t%, PPh3 ortho, 2,4JCP=12.1); 130.52 (s, PPh3 para);
132.01 (t%, PPh3 ipso, 1,3JCP=46.3); 134.85 (t%, PPh3 meta, 3,5JCP=11.1).
124.42 (s, C6H4Cl); 124.78 (s, C6H4Cl); 127.29 (s, C6H4Cl); 143.76 (s, C6H4Cl); 148.17 (s, C6H4Cl
Cq); 150.05 (t, C6H4Cl Cq, 2JCP=10.1); 177.95 (t, CO, 2JCP=8.1); 180.52 (t, CO, 2JCP=7.0); 127.5
(t%, PPh3 ortho, 2,4JCP=10.1); 130.12 (s, PPh3); 130.94 (t, PPh3 ipso, 1,3JCP=52.3); 134.5 (t%, PPh3
meta, 3,5JCP=10.1).
Os(C6H4Br-2)Cl(CO)2(PPh3)2 (6b)
125.02 (s, C6H4Br); 125.28 (s, C6H4Br); 131.68 (s, C6H4Br); 144.74 (s, C6H4Br); 148.28 (s, C6H4Br
Cq); 153.39 (t, Cq C6H4Br, 2JCP=11.1); 178.63 (t, CO, 2JCP=9.1); 180.28 (t, CO, 2JCP=6.0); 127.56
(t%, PPh3 ortho, 2,4JCP=11.1); 130.22 (s, PPh3 para); 130.98 (t%, PPh3 ipso, 1,3JCP=42.3); 134.73 (t%,
PPh3 meta, 3,5JCP=9.1).
Os(C6H4I-2)Cl(CO)2(PPh3)2 (6c)
Os(C6H4Cl-2)Cl(CS)(PPh3)2 (7a)
Os(C6H4Br-2)Cl(CS)(PPh3)2 (7b)
125.28 (s, C6H4I); 125.57 (s, C6H4I); 140.09 (s, C6H4I); 145.77 (s, C6H4I); 180.19 (t, CO,
2JCP=17.0); 180.25 (t, CO, 2JCP=17.0); 127.99 (t%, PPh3 ortho, 2,4JCP=9.1); 130.69 (s, PPh3 para);
131.32 (t, PPh3 ipso, 1,3JCP=53.3); 135.37 (t%, PPh3 meta, 3,5JCP=9.1).
122.71 (s, C6H4Cl); 124.44 (s, C6H4Cl); 127.79 (s, C6H4Cl); 136.82 (s, C6H4Cl); 127.59 (t%, PPh3
ortho, 2,4JCP=9.1); 129.87 (s, PPh3 para); 130.79 (t%, PPh3 ipso, 1,3JCP=52.3); 134.71 (t%, PPh3 meta,
3,5JCP=10.1).
122.52 (s, C6H4Br); 125.91 (s, C6H4Br); 128.36 (s, C6H4Br); 136.48 (s, C6H4Br); 138.66 (s, C6H4Br
Cq); 139.82 (t, C6H4Br Cq, 2JCP=11.0); 224.92 (t, CS, 2JCP=13.2); 127.55 (t%, PPh3 ortho,
2.4JCP=9.1); 131.27 (t%, PPh3 ipso, 1,3JCP=46.3); 134.70 (t%, PPh3 meta, 3,5JCP=10.1).
Os(C6H4Cl-2)Cl(CS)(CO)(PPh3)2 (8a) 124.39 (s, C6H4Cl); 124.87 (s, C6H4Cl); 127.76 (s, C6H4Cl); 144.03 (s, C6H4Cl); 149.63 (s, C6H4Cl
Cq); 150.84 (t, C6H4Cl Cq, 2JCP=11.1); 181.69 (t, CO, 2JCP=7.0); 127.31 (t%, PPh3 ortho,
2,4JCP=10.1); 130.17 (s, PPh3 para); 130.31 (t%, PPh3 ipso, 1,3JCP=52.3); 134.90 (t%, PPh3 meta,
3,5JCP=9.1).
Os(C6H4Br-2)Cl(CS)(CO)(PPh3)2 (8b) 124.66 (s, C6H4Br); 124.98 (s, C6H4Br); 131.94 (s, C6H4Br); 144.90 (s, C6H4Br); 143.85 (s, C6H4Br
Cq); 153.72 (t, C6H4Br Cq, 2JCP=11.1); 181.26 (t, CO, 2JCP=6.0); 127.30 (t%, PPh3 ortho,
2,4JCP=10.1); 130.19 (s, PPh3 para); 130.30 (t, PPh3 ipso, 1,3JCP=54.3); 135.02 (t, PPh3 meta
3,5JCP=10.1).
Os(h2-C[S]C6H4Cl-2)Cl(CO)(PPh3)2
(9a)
126.58 (s, C6H4Cl); 130.49 (s, C6H4Cl), 131.22 (s, C6H4Cl); 139.63 (s, C6H4Cl Cq); 139.70 (s,
C6H4Cl); 127.68 (t%, PPh3 ortho, 2,4JCP=9.1); 129.82 (s, PPh3); 131.28 (t, PPh3 ipso, 1,3JCP=51.3);
134.15 (t%, PPh3 meta, 3,5JCP=10.1).
127.66 (s, C6H4Br); 141.13 (s, C6H4Br); 190.81 (t, CO); 207.35 (t, CS); 128.24 (t%, PPh3 ortho,
2,4JCP=10.1); 134,64 (t%, PPh3 meta, 3,5JCP=10.1); 130.31 (s, PPh3 para); 131.49 (t, PPh3 ipso,
1,3JCP=34.2).
12.49 (s, CH3CH2CH2CH2); 13.79 (s, CH3CH2CH2CH2); 27.20 (s, CH3CH2CH2CH2); 28.95 (s,
CH3CH2CH2CH2); 128.06 (s, C6H4); 128.32 (s, C6H4); 137.47 (s, C6H4); 139.31 (s, C6H4); 143.73 (s,
C6H4 Cq); 148.96 (t, C6H4 Cq, 2JCP=12.07); 190.67 (t, CO, 2JCP=10.1); 127.63 (t%, PPh3 ortho,
2,4JCP=9.1); 129.8 (s, PPh3 para); 130.94 (PPh3 ipso, 1,3JCP=50.3); 134.24 (t%, PPh3 meta,
3,5JCP=10.04).
Os(h2-C[S]C6H4Br-2)Cl(CO)(PPh3)2
(9b)
Os(h2-C[S]C6H4SnnBu3-2)Cl(CO)
(PPh3)2 (10)

32
C.E.F. Rickard et al. / Journal of Organometallic Chemistry 607 (2000) 27–40

C.E.F. Rickard et al. / Journal of Organometallic Chemistry 607 (2000) 27–40
33
2.6. Lithiation of Os(p2-C[S]C6H4Br-2)Cl(CO)(PPh3)2
(9b)
Table 5
,
Selected bond lengths (A) and angles (°) for 2a
Bond lengths
OsꢀC(1)
OsꢀC(2)
OsꢀP(1)
OsꢀP(2)
OsꢀCl(1)
OsꢀCl(2)
Cl(2)ꢀC(3)
O(1)ꢀC(1)
C(2)ꢀC(7)
C(2)ꢀC(3)
C(3)ꢀC(4)
C(4)ꢀC(5)
C(5)ꢀC(6)
C(6)ꢀC(7)
Despite the lack of reactivity shown by the o-
halo-substituent in the saturated o-halophenyl com-
plexes, 5, 6, and 8, lithiation occurs readily once the
o-halophenyl group is removed from the metal as in the
migrated product 9b. Treatment of a red–purple
solution of Os(h2-C[S]C6H4Br-2)Cl(CO)(PPh3)2 (9b)
with one molar equivalent of nBuLi resulted in an
immediate colour change to bright orange. Quenching
this orange solution by the addition of excess MeI gave
a dark red mixture of Os(h2-C[S]C6H4Me-2)Cl(CO)-
(PPh3)2 and Os(h2-C[S]C6H5)Cl(CO)(PPh3)2 as con-
firmed by FAB+ mass spectroscopy. When the reaction
was repeated using nBu3SnCl as the quenching
electrophile, red–purple crystals of Os(h2-C[S]-
C6H4SnnBu3-2)Cl(CO)(PPh3)2 (10) were isolated and
characterised (see Scheme 2).
1.850(19)
2.060(16)
2.388(4)
2.401(3)
2.466(4)
2.826(4)
1.817(17)
1.062(18)
1.344(19)
1.39(2)
1.32(3)
1.40(3)
1.42(3)
1.46(2)
Bond angles
C(1)ꢀOsꢀC(2)
C(1)ꢀOsꢀP(1)
C(2)ꢀOsꢀP(1)
C(1)ꢀOsꢀP(2)
C(2)ꢀOsꢀP(2)
P(1)ꢀOsꢀP(2)
C(1)ꢀOsꢀCl(1)
C(2)ꢀOsꢀCl(1)
P(1)ꢀOsꢀCl(1)
P(2)ꢀOsꢀCl(1)
C(1)ꢀOsꢀCl(2)
C(2)ꢀOsꢀCl(2)
P(1)ꢀOsꢀCl(2)
P(2)ꢀOsꢀCl(2)
Cl(1)ꢀOsꢀCl(2)
C(3)ꢀCl(2)ꢀOs
O(1)ꢀC(1)ꢀOs
C(7)ꢀC(2)ꢀOs
C(3)ꢀC(2)ꢀOs
C(4)ꢀC(3)ꢀCl(2)
C(2)ꢀC(3)ꢀCl(2)
94.2(6)
88.8(5)
92.6(4)
89.9(5)
91.7(4)
175.58(13)
112.6(5)
153.1(5)
86.56(13)
90.05(12)
157.2(5)
63.1(5)
94.05(13)
88.79(13)
90.18(13)
73.7(6)
175.2(15)
129.6(13)
113.1(12)
118.4(15)
110.1(12)
Table 6
,
Selected bond lengths (A) and angles (°) for 2b
Bond lengths
OsꢀC(1)
OsꢀC(2)
OsꢀP(2)
OsꢀP(1)
OsꢀCl
1.807(7)
2.038(7)
2.3824(17)
2.4017(17)
2.4675(16)
2.8323(8)
1.930(7)
OsꢀBr
BrꢀC(3)
O(1)ꢀC(1)
C(2)ꢀC(7)
C(2)ꢀC(3)
C(3)ꢀC(4)
C(4)ꢀC(5)
C(5)ꢀC(6)
C(6)ꢀC(7)
1.152(9)
1.392(9)
1.391(10)
1.384(10)
1.397(13)
1.383(14)
1.447(11)
Bond angles
C(1)ꢀOsꢀC(2)
C(1)ꢀOsꢀP(2)
C(2)ꢀOsꢀP(2)
C(1)ꢀOsꢀP(1)
C(2)ꢀOsꢀP(1)
P(2)ꢀOsꢀP(1)
C(1)ꢀOsꢀCl
C(2)ꢀOsꢀCl
P(2)ꢀOsꢀCl
P(1)ꢀOsꢀCl
C(1)ꢀOsꢀBr
C(2)ꢀOsꢀBr
P(2)ꢀOsꢀBr
P(1)ꢀOsꢀBr
ClꢀOsꢀBr
91.6(3)
88.7(2)
92.5(2)
89.2(2)
93.2(2)
2.5. o-Halophenyl complexes as potential precursors of
benzyne complexes
Based on the route to benzyne complexes established
by Bennett et al. [3] the compounds 1, 2, 5, 6, 7, and 8
appeared to be ideal precursors to both coordinatively
unsaturated, 11, and coordinatively saturated benzyne
complexes, 12, as shown in Scheme 3. Unfortunately,
all attempts at reduction, whether beginning with
the five coordinate or six coordinate o-halophenyl
complexes were unsuccessful. In the case of the five
coordinate, starting materials reactions occurred but no
tractable products could be isolated, and in the case of
the six coordinate starting materials, no reaction was
observed. The reducing reagents investigated included,
173.97(6)
111.3(2)
157.0(2)
89.77(6)
85.75(6)
158.0(2)
66.5(2)
89.72(4)
94.37(4)
90.60(4)
71.0(2)
178.5(7)
132.2(5)
111.7(5)
122.3(6)
110.8(5)
C(3)ꢀBrꢀOs
O(1)ꢀC(1)ꢀOs
C(7)ꢀC(2)ꢀOs
C(3)ꢀC(2)ꢀOs
C(4)ꢀC(3)ꢀBr
C(2)ꢀC(3)ꢀBr
t
nBuLi, BuLi, 1–5% Na/Hg amalgam, activated zinc,
and activated magnesium.

34
C.E.F. Rickard et al. / Journal of Organometallic Chemistry 607 (2000) 27–40
Table 7
Table 8
,
,
Selected bond lengths (A) and angles (°) for 2c
Selected bond lengths (A) and angles (°) for 6a
Bond lengths
OsꢀC(1)
OsꢀC(2)
OsꢀP(1)
OsꢀP(2)
OsꢀCl
Bond lengths
OsꢀC(2)
OsꢀC(1)
OsꢀC(3)
OsꢀP(1)
OsꢀCl(1)
OsꢀP(2)
Cl(2)ꢀC(4)
C(1)ꢀO(1)
C(2)ꢀO(2)
C(3)ꢀC(4)
C(3)ꢀC(8)
C(4)ꢀC(5)
C(5)ꢀC(6)
C(6)ꢀC(7)
C(7)ꢀC(8)
1.794(8)
2.105(8)
1.917(8)
1.959(7)
2.169(6)
2.4142(14)
2.4295(17)
2.4365(15)
1.761(7)
1.080(8)
1.067(8)
1.388(9)
1.457(9)
1.386(10)
1.367(11)
1.372(11)
1.372(10)
2.3770(18)
2.4007(18)
2.4672(18)
2.9335(6)
2.125(7)
1.127(10)
1.370(10)
1.395(10)
1.380(11)
1.411(13)
1.383(13)
1.417(10)
OsꢀI
IꢀC(3)
O(1)ꢀC(1)
C(2)ꢀC(7)
C(2)ꢀC(3)
C(3)ꢀC(4)
C(4)ꢀC(5)
C(5)ꢀC(6)
C(6)ꢀC(7)
Bond angles
C(1)ꢀOsꢀC(2)
C(1)ꢀOsꢀP(1)
C(2)ꢀOsꢀP(1)
C(1)ꢀOsꢀP(2)
C(2)ꢀOsꢀP(2)
P(1)ꢀOsꢀP(2)
C(1)ꢀOsꢀCl
C(2)ꢀOsꢀCl
P(1)ꢀOsꢀCl
P(2)ꢀOsꢀCl
C(1)ꢀOsꢀI
90.3(3)
89.7(2)
93.9(2)
88.8(2)
91.2(2)
Bond angles
C(2)ꢀOsꢀC(1)
C(2)ꢀOsꢀC(3)
C(1)ꢀOsꢀC(3)
C(2)ꢀOsꢀP(1)
C(1)ꢀOsꢀP(1)
C(3)ꢀOsꢀP(1)
C(2)ꢀOsꢀCl(1)
C(1)ꢀOsꢀCl(1)
C(3)ꢀOsꢀCl(1)
P(1)ꢀOsꢀCl(1)
C(2)ꢀOsꢀP(2)
C(1)ꢀOsꢀP(2)
C(3)ꢀOsꢀP(2)
P(1)ꢀOsꢀP(2)
Cl(1)ꢀOsꢀP(2)
O(1)ꢀC(1)ꢀOs
O(2)ꢀC(2)ꢀOs
C(4)ꢀC(3)ꢀOs
C(8)ꢀC(3)ꢀOs
C(5)ꢀC(4)ꢀCl(2)
C(3)ꢀC(4)ꢀCl(2)
87.8(3)
94.9(2)
177.2(2)
87.18(19)
92.46(19)
88.10(16)
176.30(19)
88.58(18)
88.71(17)
92.26(6)
96.13(19)
87.97(19)
91.32(16)
176.68(5)
84.46(6)
175.4(6)
172.5(6)
130.1(5)
118.1(4)
113.7(5)
120.4(5)
174.71(6)
110.7(3)
159.0(2)
86.54(6)
89.27(6)
158.6(3)
68.4(2)
93.74(4)
89.52(5)
90.60(4)
68.91(19)
177.4(7)
131.1(5)
112.6(5)
123.5(6)
110.1(5)
C(2)ꢀOsꢀI
P(1)ꢀOsꢀI
P(2)ꢀOsꢀI
ClꢀOsꢀI
C(3)ꢀIꢀOs
O(1)ꢀC(1)ꢀOs
C(7)ꢀC(2)ꢀOs
C(3)ꢀC(2)ꢀOs
C(4)ꢀC(3)ꢀI
C(2)ꢀC(3)ꢀI
2.7. Summary
Sets of o-halophenyl derivatives of ruthenium(II) and
osmium(II) have been prepared for the purpose of
examining the potential of these compounds as precur-
sors, through reduction, to ruthenium(0) and os-
mium(0) benzyne complexes. No routes to benzyne
complexes were found using these starting materials,
but it was established that when the o-halophenyl
group is bound in coordinatively unsaturated com-
plexes, there is a bonding interaction between the halo-
gen substituent and the metal centre. When
a
thiocarbonyl ligand is presented adjacent to the o-
halophenyl ligand, migratory insertion reactions ensue
leading to h2-thioacyl complexes. In the latter com-
pounds, where the o-halophenyl group is no longer
bound to the metal, normal organic reactivity returns
to the halogen substituents as exemplified by ready
lithiation and subsequent stannylation.
Fig. 2. Molecular geometry of Os(C6H4Cl-2)Cl(CO)(PPh3)2 (2a).

C.E.F. Rickard et al. / Journal of Organometallic Chemistry 607 (2000) 27–40
35
Fig. 3. Molecular geometry of Os(C6H4Cl-2)Cl(CO)2(PPh3)2 (6a).
3. Experimental
3.1. General procedures and instruments
Scheme 2. Synthesis and reactions of the thiocarbonyl-containing
o-halophenyl complexes, Os(C6H4X-2)Cl(CS)(PPh3)2.
Standard laboratory procedures were followed as
have been described previously [10]. The compounds
RuHCl(CO)(PPh3)3 [11], OsHCl(CO)(PPh3)3 [12],
OsHCl(CS)(PPh3)3 [13], Hg(C6H4Cl-2)2 [6], Hg-
(C6H4Br-2)2 [14], and Hg(C6H4I-2)2 [15], were prepared
according to literature methods.
quoted in ppm and 1H-NMR spectra referenced to
either tetramethylsilane (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). Mass spectra were recorded using the fast atom
bombardment technique with a Varian VG 70-SE mass
spectrometer. Melting points (uncorrected) were
Infrared 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 Bruker DRX 400 at 25°C. 1H- and
13C-NMR spectra were obtained operating at 400.1
(1H) or 100.6 (13C) MHz, respectively. Resonances are
determined on
a Reichert hot stage microscope.
Elemental analyses were obtained from the Micro-
analytical Laboratory, University of Otago.
Fig. 4. Selected structural data for five coordinate (Os(C6H4X-2)Cl(CO)(PPh3)2) and six coordinate (Os(C6H4Cl-2)Cl(CO)2(PPh3)2) o-halophenyl
complexes of osmium. (View down PꢀOsꢀP axis, PPh3 ligands omitted for clarity.)

36
C.E.F. Rickard et al. / Journal of Organometallic Chemistry 607 (2000) 27–40
Fig. 6. Molecular geometry of Os(h2-C[S]C6H4Cl-2)Cl(CO)(PPh3)2
(9a).
Fig. 5. Molecular geometry of Os(C6H4Cl-2)Cl(CO)(CS)(PPh3)2 (8a).
Table 9
Table 10
,
Selected bond lengths (A) and angles (°) for 8a
,
Selected bond lengths (A) and angles (°) for 9a
Bond lengths
OsꢀC(2)
OsꢀC(1)
OsꢀC(3)
OsꢀP(2)
Bond lengths
OsꢀC(1)
OsꢀC(2)
OsꢀP(2)
OsꢀP(1)
OsꢀCl(1)
OsꢀS
1.872(7)
1.913(7)
2.169(6)
2.4492(14)
2.4521(14)
2.4895(16)
1.753(6)
1.519(7)
1.155(7)
1.414(7)
1.445(8)
1.382(8)
1.370(9)
1.380(8)
1.367(8)
1.857(3)
1.961(3)
2.4009(6)
2.4075(7)
2.4938(6)
2.4989(7)
1.695(3)
1.175(3)
1.450(4)
1.389(4)
1.430(4)
1.386(4)
1.382(5)
1.392(5)
1.384(4)
OsꢀP(1)
OsꢀCl(1)
Cl(2)ꢀC(4)
SꢀC(2)
SꢀC(2)
OꢀC(1)
OꢀC(1)
C(2)ꢀC(3)
C(3)ꢀC(8)
C(3)ꢀC(4)
C(4)ꢀC(5)
C(5)ꢀC(6)
C(6)ꢀC(7)
C(7)ꢀC(8)
C(3)ꢀC(4)
C(3)ꢀC(8)
C(4)ꢀC(5)
C(5)ꢀC(6)
C(6)ꢀC(7)
C(7)ꢀC(8)
Bond angles
Bond angles
C(1)ꢀOsꢀC(2)
C(1)ꢀOsꢀP(2)
C(2)ꢀOsꢀP(2)
C(1)ꢀOsꢀP(1)
C(2)ꢀOsꢀP(1)
P(2)ꢀOsꢀP(1)
C(1)ꢀOsꢀCl(1)
C(2)ꢀOsꢀCl(1)
P(2)ꢀOsꢀCl(1)
P(1)ꢀOsꢀCl(1)
C(1)ꢀOsꢀS
C(2)ꢀOsꢀS
P(2)ꢀOsꢀS
P(1)ꢀOsꢀS
Cl(1)ꢀOsꢀS
C(2)ꢀSꢀOs
OꢀC(1)ꢀOs
C(3)ꢀC(2)ꢀOs
SꢀC(2)ꢀOs
C(5)ꢀC(4)ꢀCl(2)
C(3)ꢀC(4)ꢀCl(2)
C(2)ꢀOsꢀC(1)
C(2)ꢀOsꢀC(3)
C(1)ꢀOsꢀC(3)
C(2)ꢀOsꢀP(2)
C(1)ꢀOsꢀP(2)
C(3)ꢀOsꢀP(2)
C(2)ꢀOsꢀP(1)
C(1)ꢀOsꢀP(1)
C(3)ꢀOsꢀP(1)
P(2)ꢀOsꢀP(1)
C(2)ꢀOsꢀCl(1)
C(1)ꢀOsꢀCl(1)
C(3)ꢀOsꢀCl(1)
P(2)ꢀOsꢀCl(1)
P(1)ꢀOsꢀCl(1)
OꢀC(1)ꢀOs
92.6(3)
95.2(2)
106.75(12)
89.15(9)
89.79(8)
88.19(9)
90.31(8)
177.26(2)
103.76(9)
149.50(8)
90.66(2)
90.64(2)
149.33(9)
42.59(8)
90.23(2)
91.70(2)
106.91(2)
51.51(9)
176.6(3)
142.3(2)
85.90(12)
116.7(3)
121.9(2)
171.4(3)
84.66(19)
89.36(19)
87.86(14)
97.57(19)
90.39(19)
92.06(14)
177.76(6)
176.0(2)
83.4(2)
88.72(16)
94.96(5)
82.81(5)
175.8(7)
173.6(4)
130.8(5)
118.3(4)
113.2(5)
121.1(5)
SꢀC(2)ꢀOs
C(4)ꢀC(3)ꢀOs
C(8)ꢀC(3)ꢀOs
C(5)ꢀC(4)ꢀCl(2)
C(3)ꢀC(4)ꢀCl(2)

C.E.F. Rickard et al. / Journal of Organometallic Chemistry 607 (2000) 27–40
37
3.2. Ru(C6H4Cl-2)Cl(CO)(PPh3)2 (1a)
Table 11
,
Selected bond lengths (A) and angles (°) for 9b
RuHCl(CO)(PPh3)3 (200 mg, 0.210 mmol) and
Hg(C6H4Cl-2)2 (98 mg, 0.23 mmol) were heated under
reflux in toluene for 24 h. The resulting yellow solution
was cooled, and the toluene was removed in vacuo. The
product was dissolved in dichloromethane (20 ml),
filtered through a Celite pad to remove elemental
mercury and ethanol (10 ml) was then added. Removal
of the dichloromethane on a rotary evaporator yielded
bright yellow crystals of 1a (135 mg, 80%). M.p.
180–181°C. m/z 765; C43H34ClOP2Ru [M+−C] 765.
Anal. Calc. for C43H34Cl2OP2Ru·1/4CH2Cl2: C, 63.22;
H, 4.23. Found: C, 63.21; H, 4.29%.
Bond lengths
OsꢀC(1)
OsꢀC(2)
OsꢀP(2)
OsꢀP(1)
OsꢀCl
OsꢀS
BrꢀC(4)
SꢀC(2)
1.854(4)
1.957(4)
2.3998(9)
2.4047(9)
2.4942(9)
2.4988(10)
1.889(5)
1.696(4)
1.159(5)
1.447(5)
1.401(6)
1.419(6)
1.385(6)
1.384(7)
1.402(7)
1.392(6)
OꢀC(1)
C(2)ꢀC(3)
C(3)ꢀC(8)
C(3)ꢀC(4)
C(4)ꢀC(5)
C(5)ꢀC(6)
C(6)ꢀC(7)
C(7)ꢀC(8)
3.3. Ru(C6H4Br-2)Cl(CO)(PPh3)2 (1b)
To a dichloromethane (10 ml) solution of Ru-
(C6H4Br-2)(h2-O2CCH3)(CO)(PPh3)2 (3) (see Section
3.7) (50 mg, 0.0575 mmol), one drop of HCl (conc.) in
EtOH (5 ml) was added. The resulting bright yellow
solution was reduced in volume on the rotary
evaporator and yellow crystals of 1b were filtered off
and collected (47 mg, 97%). m/z 844.0042; C43H34-
OBrClRuP2 requires 844.0000. Anal. Calc. for C43H34-
BrClRuOP2·H2O: C, 59.84; H, 4.20. Found: C, 60.26;
H, 4.17%.
Bond angles
C(1)ꢀOsꢀC(2)
C(1)ꢀOsꢀP(2)
C(2)ꢀOsꢀP(2)
C(1)ꢀOsꢀP(1)
C(2)ꢀOsꢀP(1)
P(2)ꢀOsꢀP(1)
C(1)ꢀOsꢀCl
C(2)ꢀOsꢀCl
P(2)ꢀOsꢀCl
P(1)ꢀOsꢀCl
C(1)ꢀOsꢀS
107.23(17)
89.41(12)
89.74(10)
88.44(12)
90.24(10)
177.74(3)
103.43(12)
149.33(12)
90.54(3)
90.64(3)
149.85(12)
42.61(12)
90.23(3)
C(2)ꢀOsꢀS
P(2)ꢀOsꢀS
P(1)ꢀOsꢀS
3.4. Os(C6H4Cl-2)Cl(CO)(PPh3)2 (2a)
91.28(3)
ClꢀOsꢀS
C(2)ꢀSꢀOs
106.72(3)
51.39(13)
175.9(4)
131.4(3)
142.6(3)
86.00(17)
116.1(4)
122.2(3)
OsHCl(CO)(PPh3)3 (200 mg, 0.192 mmol) and
Hg(C6H4Cl-2)2 (90 mg, 0.21 mmol) were added to
toluene (50 ml) and the mixture heated under reflux for
3 h. The resulting yellow solution was cooled, and the
toluene was removed in vacuo. The product was
dissolved in dichloromethane (20 ml), filtered through a
Celite pad to remove elemental mercury and ethanol
(10 ml) was then added. Removal of the dichloro-
methane on a rotary evaporator yielded bright orange–
yellow crystals of 2a (152 mg, 89%). M.p. 224–225°C.
m/z 890.1075; C43H34Cl2OsOP2 requires 890.1077.
Anal. Calc. for C43H34Cl2OsOP2: C, 58.04; H, 3.85.
Found: C, 57.58; H, 3.82%.
OꢀC(1)ꢀOs
C(3)ꢀC(2)ꢀS
C(3)ꢀC(2)ꢀOs
SꢀC(2)ꢀOs
C(5)ꢀC(4)ꢀBr
C(3)ꢀC(4)ꢀBr
3.5. Os(C6H4Br-2)Cl(CO)(PPh3)2 (2b)
To
a
dichloromethane solution (10 ml) of
Os(C6H4Br-2)(h2-O2CCH3)(CO)(PPh3)2 (4) (see Section
3.8) (50 mg, 0.052 mmol) one drop of HCl (conc.) in
EtOH (5 ml) was added. The resulting bright yellow
solution was reduced in volume on the rotary evapora-
tor and yellow crystals of 2b were filtered off and
collected (47 mg, 97%). m/z 934.0581; C43H34-
OBrClOsP2 requires 934.0572. Anal. Calc. for
C43H34BrClOsOP2: C, 55.28; H, 3.67. Found: C, 55.46;
H, 3.74%.
Scheme 3. Proposed synthetic routes to benzyne complexes.

38
C.E.F. Rickard et al. / Journal of Organometallic Chemistry 607 (2000) 27–40
3.6. Os(C6H4I-2)Cl(CO)(PPh3)2 (2c)
filtered off and collected (89 mg, 86%). Anal. Calc. for
C44H34BrClO2P2Ru·0.5CH2Cl2: C, 58.40; H, 3.86.
Found: C, 58.52; H, 3.88%.
OsHCl(CO)(PPh3)3 (200 mg, 0.192 mmol) was
treated with Hg(C6H4I-2)2 (129 mg, 0.211 mmol) as
described for 2a to give, after isolation, bright yellow
crystals of 2c (143 mg, 76%). M.p. 230°C. Anal. Calc.
for C43H34ClIOOsP2·CH2Cl2: C, 49.57; H, 3.40. Found:
C, 49.13; H, 3.14%.
3.11. Os(C6H4Cl-2)Cl(CO)2(PPh3)2 (6a)
Os(C6H4Cl-2)Cl(CO)(PPh3)2 (100 mg, 0.112 mmol)
was dissolved in dichloromethane (25 ml) and the solu-
tion was added to a Fischer–Porter bottle. The bright
yellow solution was subjected to carbon monoxide (4
atm) for 15 min, the pressure released, and ethanol (10
ml) was added. The solvent volume was reduced on a
rotary evaporator to give colourless crystals of pure 6a
that were filtered off and collected (90 mg, 87%). M.p.
220–221°C. m/z 890, 883; C43H34Cl2OOsP2 [M+−CO]
requires 890 C44H34ClO2OsP2 [M+−Cl] requires 883.
Anal. Calc. for C44H34Cl2O2OsP2: C, 57.58; H, 3.73.
Found: C, 57.27; H, 3.73%.
3.7. Ru(C6H4Br-2)(p2-O2CCH3)(CO)(PPh3)2 (3)
RuHCl(CO)(PPh3)3 (200 mg, 0.210 mmol) and
Hg(C6H4Br-2)2 (108 mg, 0.211 mmol) were added to
toluene (50 ml) and the solution was heated under
reflux for 24 h, cooled, and the toluene removed in
vacuo. Dichloromethane (25 ml) and NaOAc (34 mg,
0.42 mmol) in H2O:EtOH 1:9 ml were added to the
residue. Evaporation of the solvent gave pale yellow
crystals of
3 (133 mg, 73%). Anal. Calc. for
C45H37BrO3RuP2·0.25CH2Cl2: C, 61.08; H, 4.25.
Found: C, 60.86; H, 4.29%.
3.12. Os(C6H4Br-2)Cl(CO)2(PPh3)2 (6b)
3.8. Os(C6H4Br-2)(p2-O2CCH3)(CO)(PPh3)2 (4)
Os(C6H4Br-2)(h2-O2CCH3)(CO)(PPh3)2 (100 mg,
0.107 mmol) was dissolved in dichloromethane (25 ml)
and the solution added to a Fischer–Porter bottle. The
solution was acidified with HCl (aq, one drop) and LiCl
(20 mg, 0.472 mmol) was added. Subsequent treatment
with carbon monoxide (4 atm), addition of ethanol (10
ml) and reduction of the solvent volume on a rotary
evaporator yielded colourless crystals of 6b that were
filtered off and collected (90 mg, 87%). m/z 927.0832,
C44H34BrO2OsP2 [M+−Cl] requires 927.0832. Anal.
Calc. for C44H34BrClO2OsP2: C, 54.92; H, 3.56. Found:
C, 54.83; H, 3.58%.
OsHCl(CO)(PPh3)3 (200 mg, 0.192 mmol) and
Hg(C6H4Br-2)2 (108 mg, 0.211 mmol) were treated as
in Section 3.7 to give pale yellow crystals of 4 (136
mg, 74%). m/z 958.0935; C45H37BrO3OsP2 requires
958.1016. Anal. Calc. for C45H37BrO3OsP2·0.25C7H8:
C, 57.24; H, 4.01. Found: C, 57.27; H, 3.73%.
3.9. Ru(C6H4Cl-2)Cl(CO)2(PPh3)2 (5a)
Ru(C6H4Cl-2)Cl(CO)(PPh3)2 (100 mg, 0.125 mmol)
was dissolved in dichloromethane (25 ml) and the
solution was added to a Fischer–Porter bottle. The
bright yellow solution was subjected to carbon
monoxide (4 atm) for 15 min, the pressure released, and
ethanol (10 ml) was added. The solvent volume was
reduced on a rotary evaporator to give colourless
crystals of pure 5a (94 mg, 91%). m/z 800, 793;
C43H34Cl2OP2Ru [M+−CO] requires 800, C44H34ClO2-
P2Ru [M+−Cl] requires 793. Anal. Calc. for C44H34-
Cl2O2P2Ru·0.25CH2Cl2: C, 62.55; H, 4.09. Found: C,
62.65; H, 4.14%.
3.13. Os(C6H4I-2)Cl(CO)2(PPh3)2 (6c)
Os(C6H4I-2)Cl(CO)(PPh3)2 (100 mg, 0.102 mmol)
was dissolved in dichloromethane (25 ml) and the solu-
tion added to a Fischer–Porter bottle and treated with
carbon monoxide (4 atm), as described for 6a, to yield
colourless crystals of 6c (89 mg, 89%). m/z 1010;
C44H34ClIO2P2Os requires 1010. Anal. Calc. for
C44H34ClIO2P2Os·CH2Cl2: C, 49.40; H, 3.32. Found: C,
49.37; H, 3.16%.
3.10. Ru(C6H4Br-2)Cl(CO)2(PPh3)2 (5b)
3.14. Os(C6H4Cl-2)Cl(CS)(PPh3)2 (7a)
Ru(C6H4Br-2)(h2-O2CCH3)(CO)(PPh3)2 (100 mg,
0.118 mmol) was dissolved in dichloromethane (25 ml)
and the solution added to a Fischer–Porter bottle. The
solution was acidified with HCl (aq, one drop) and LiCl
(20 mg, 0.472 mmol) was added. Subsequent treatment
with carbon monoxide (4 atm), addition of ethanol (10
ml) and reduction of the solvent volume on a rotary
evaporator yielded colourless crystals of 5b that were
OsHCl(CS)(PPh3)3 (200 mg, 0.189 mmol) was treated
with Hg(C6H4Cl-2)2 (90 mg, 0.21 mmol) as described
for 2a, except that the mixture was heated under reflux
for 4 h, to give, after isolation, bright yellow crystals of
complex 7a (79%, 138 mg). m/z 906.0839; C43H34Cl2-
OsP2S requires 906.0848. Anal. Calc. for C43H34Cl2-
OsP2S: C, 57.01; H, 3.78. Found: C, 56.51; H, 4.12%.

C.E.F. Rickard et al. / Journal of Organometallic Chemistry 607 (2000) 27–40
39
3.15. Os(C6H4Br-2)Cl(CS)(PPh3)2 (7b)
in dichloromethane (10 ml). Ethanol (5 ml) was added,
and the dichloromethane was removed on a rotary
evaporator to give purple crystals of complex 9b which
were further recrystallised from dichloromethane:
ethanol (15:5 ml) (89 mg, 89%). m/z 978.0270;
C44H34BrClOOsP2S requires 978.0292. Anal. Calc. for
C44H34BrClOOsP2S·CH2Cl2: C, 50.83; H, 3.41. Found:
C, 50.62; H, 3.83%.
OsHCl(CS)(PPh3)3 (200 mg, 0.189 mmol) was treated
with Hg(C6H4Br-2)2 (107 mg, 0.208 mmol) as described
for 2a to give bright yellow crystals of 7b (79%, 142
mg). m/z 950.0251; C43H37ClBrOsP2S requires
950.0343. Anal. Calc. for C43H37ClBrOsP2S: C, 54.35;
H, 3.61. Found: C, 54.05; H, 3.76%.
3.16. Os(C6H4Cl-2)Cl(CS)(CO)(PPh3)2 (8a)
3.20. Os(p2-CS{C6H4SnBu3-2})Cl(CO)(PPh3)2 (10)
Os(C6H4Cl-2)Cl(CS)(PPh3)2 (100 mg, 0.105 mmol)
was dissolved in dichloromethane (25 ml) and the solu-
tion added to a Fischer–Porter bottle which was then
pressured with carbon monoxide (4 atm). Ethanol (10
ml) was added, the dichloromethane removed on a
rotary evaporator, and colourless crystals of 8a were
collected (78 mg, 76%). M.p. 224–225°C. m/z 906.0715,
Os(h2-CS{C6H4Br-2})Cl(CO)(PPh3)2 (100 mg, 0.102
mmol) was dissolved in dry, deoxygenated THF (50 ml)
at 40°C. The deep-purple solution was cooled to
n
−78°C and a solution of BuLi (0.102 ml, 1 M, 0.102
mmol) was added. The colour changed instantly to
bright orange. The solution was stirred for 5 min at
−78°C and Bu3SnCl (0.139 ml, 0.425 mmol) was added
slowly. The solution was allowed to warm to r.t.,
during which time it reverted from bright orange to a
dark purple colour. Water and ethanol were added and
the THF was removed on a rotary evaporator. The red
solid was decanted from the solution, filtered off, and
recrystallised from dichloromethane:hexane (20:5 ml) to
yield purplish–red crystals of 10 (81 mg, 67%). Anal.
Calc. for C56H61ClOOsP2SSn: C, 56.60; H, 5.17. Found:
C, 56.70; H, 5.32%.
C43H34Cl2OsP2S
899.1079, C44H34ClOOsP2S
[M+−CO]
requires
906.0848;
requires
[M+−Cl]
899.1109. Anal. Calc. for C44H34Cl2OOsP2S·H2O: C,
55.52; H, 3.81. Found: C, 55.77; H, 3.98%.
3.17. Os(C6H4Br-2)Cl(CS)(CO)(PPh3)2 (8b)
Os(C6H4Br-2)Cl(CS)(PPh3)2 (100 mg, 0.105 mmol)
was dissolved in dichloromethane (25 ml) and the solu-
tion added to a Fischer–Porter bottle and treated with
carbon monoxide to give a colourless solution. Ethanol
(5 ml) was added, the dichloromethane (10 ml) removed
on a rotary evaporator, and complex 8b was filtered off
and collected (78 mg, 76%). Anal. Calc. for
C44H34BrClOOsP2S·CH2Cl2: C, 50.83; H, 3.41. Found:
C, 50.42; H, 3.72%.
3.21. X-ray crystal structure determinations of 2a, 2b,
2c, 6a, 8a, 9a and 9b
X-ray data collection for 2a, 2b, 2c, 6a, 8a, 9a and 9b
was on a Siemens SMART diffractometer with a CCD
area detector, using graphite monochromated Mo–Ka
,
radiation (u=0.71073 A). Data were integrated and
3.18. Os(p2-CS{C6H4Cl-2})Cl(CO)(PPh3)2 (9a)
Lorentz and polarisation correction applied using
SAINT [16] software. Semi-empirical absorption correc-
tions were applied based on equivalent reflections using
SADABS [17]. The structures were solved by Patterson
and Fourier methods and refined by full-matrix least-
squares on F2 using programs SHELXS [18] and SHELXL
[19]. Complexes 2a, 2b and 2c are isostructural as are 9a
and 9b. In these cases the known structure was used as
a starting point for the subsequent refinements. All
non-hydrogen atoms were refined anisotropically 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 4.
Os(C6H4Cl-2)Cl(CO)(CS)(PPh3)2 (100 mg, 0.105
mmol) was dissolved in toluene. After 5 min heating
under reflux, the toluene was removed from the pur-
plish–red solution in vacuo. The purple residue was
redissolved in dichloromethane (15 ml), ethanol (5 ml)
was added, and the dichloromethane removed on a
rotary evaporator to give 9a which was filtered off and
subsequently recrystallised from dichloromethane:
ethanol (15:5 ml) (88 mg, 88%). M.p. 225–226°C. m/z
934.0782, C44H34Cl2OOsP2S requires 934.0798. Anal.
Calc. for C44H34Cl2OOsP2S·CH2Cl2: C, 53.05; H, 3.56.
Found: C, 53.00; H, 3.66%.
3.19. Os(p2-CS{C6H4Br-2})Cl(CO)(PPh3)2 (9b)
Os(C6H4Br-2)Cl(CO)(CS)(PPh3)2 (100 mg, 0.105
mmol) was dissolved in toluene (25 ml). After 5 min
heating under reflux, the toluene was removed from the
purplish–red solution and the residue was redissolved
4. Supplementary material
Crystallographic data (excluding structure factors)
for the structures reported have been deposited with the

40
C.E.F. Rickard et al. / Journal of Organometallic Chemistry 607 (2000) 27–40
Bennett, T. Dirnberger, D.C.R. Hockless, E. Wenger, A.C.
Willis, J. Chem. Soc. Dalton Trans. (1998) 271.
Cambridge Crystallographic Data Centre as supple-
mentary publication nos. 139392–139398 for 2a, 2b, 2c,
6a, 8a, 9a and 9b, respectively. Copies of this informa-
tion can be obtained free of charge from the Director,
CCDC, 12 Union Road, Cambridge, CB2 1EZ, UK
(fax: +44-1223-336033; e-mail: deposit@ccdc.cam.
ac.uk or www: http://www.ccdc.cam.ac.uk.
[4] (a) W.R. Roper, L.J. Wright, J. Organomet. Chem. 142 (1977)
C1. (b) C.E.F. Rickard, W.R. Roper, G.E. Taylor, J.M. Waters,
L.J. Wright, J. Organomet. Chem. 389 (1990) 375. (c) M.M.P.
Ng, W.R. Roper, L.J. Wright, Organometallics 13 (1994) 2563.
(d) G.R. Clark, M.M.P. Ng, W.R. Roper, L.J. Wright, J.
Organomet. Chem. 491 (1995) 219. (e) K. Hu¨bler, U. Hu¨bler,
W.R. Roper, L.J. Wright, J. Organomet. Chem. 526 (1996) 199.
(f) A.M. Clark, C.E.F. Rickard, W.R. Roper, L.J. Wright, J.
Organomet. Chem. 545–546 (1997) 619.
Acknowledgements
[5] G.R. Clark, C.E.L. Headford, W.R. Roper, L.J. Wright, V.P.D.
Yap, Inorg. Chim. Acta 220 (1994) 261.
[6] L.G. Makarova, A.N. Nesmeyanov, The Organic Compounds of
Mercury, North-Holland, Amsterdam, 1967.
[7] R.H. Crabtree, J.W. Faller, M.F. Mellea, J.M. Quirk,
Organometallics 1 (1982) 1361.
[8] M.D. Butts, B.L. Scott, G.L. Kubas, J. Am. Chem. Soc. 118
(1996) 11831.
We thank the University of Auckland Research
Committee for partial support of this work through
grants-in-aid and through the award of a Doctoral
Scholarship to SDW.
[9] G.R. Clark, T.J. Collins, K. Marsden, W.R. Roper, J.
Organomet. Chem. 259 (1983) 215.
[10] S.M. Maddock, C.E.F. Rickard, W.R. Roper, L.J. Wright,
Organometallics 15 (1996) 1793.
[11] P.S. Hallman, B.R. McGarvey, G. Wilkinson, J. Chem. Soc. (A)
(1968) 3143.
[12] L. Vaska, J. Am. Chem. Soc. 86 (1964) 1943.
[13] G.P. Elliott, N.M. McAuley, W.R. Roper, Inorg. Synth. 26
(1989) 184.
[14] (a) M.E. Hanke, J. Am. Chem. Soc. 45 (1923) 1321. (b) M.S.
Kharasch, H. Pines, J.H. Levine, J. Org. Chem. 3 (1938) 347.
[15] (a) L.M. Yagupol’skii, V.I. Popov, N.V. Kondratenko, Zh. Org.
Khim. 12 (1976) 916. (b) R.P. Rao, S.H. Singh, S. Raj, N.B.
Zaidi, B. Singh, Indian J. Chem. Sect. B 18 (1979) 377.
[16] SAINT, Area detector integration software, Siemens Analytical
Instruments Inc., Madison, WI, 1995.
[17] G.M. Sheldrick, SADABS, Program for semi-empirical absorption
correction, University of Go¨ttingen, Germany, 1977.
[18] G.M. Sheldrick, SHELXS, Program for crystal structure determi-
nation, University of Go¨ttingen, Germany, 1977.
References
[1] (a) S.B. Miller, B.L. Jelus, J.H. Smith, B. Munson, T.B. Brill, J.
Organomet. Chem. 170 (1979) 9. (b) N.A.A. Al-Jabar, A.G.
Massey, J. Organomet. Chem. 288 (1985) 145. (c) K. Mochida,
T. Yamanishi, J. Organomet. Chem. 322 (1987) 247. (d) C.
Eaborn, B. Singh, J. Organomet. Chem. 177 (1979) 333. (e) M.
Schu¨rmann, F. Huber, J. Organomet. Chem. 530 (1997) 121. (f)
F. Huber, H. Preut, D. Scholz, M. Schu¨rmann, J. Organomet.
Chem. 441 (1992) 227.
[2] (a) D.R. Fahey, J. Am. Chem. Soc. 92 (1970) 402. (b) D.R.
Fahey, J.E. Mahan, J. Am. Chem. Soc. 99 (1977) 2501. (c) C.
Butler, C. Eaborn, A. Pidcock, J. Organomet. Chem. 144 (1978)
C23. (d) M. Crespo, J. Sales, X. Solans, M.F. Altaba, J. Chem.
Soc. Dalton Trans. (1988) 1617. (e) M. Crespo, J. Sales, J.
Organomet. Chem. 322 (1987) 405. (f) M. Crespo, O. Rosell, J.
Sales, M. Reco, J. Organomet. Chem. 273 (1984) 415.
[3] (a) M.A. Bennett, T.W. Hambley, N.K. Roberts, G.B. Robert-
son, Organometallics
4 (1985) 1992. (b) M.A. Bennett, E.
[19] G.M. Sheldrick, SADABS, Program for crystal structure refine-
ment, University of Go¨ttingen, Germany, 1977.
Wenger, Chem. Ber. 130 (1997) 1029. (c) M.A. Bennett, D.C.R.
Hockless, E. Wenger, Polyhedron 14 (1995) 2637. (d) M.A.
.