Hybrid dibismuthines and distibines as ligands towards transition metal carbonyls

Article abstract of DOI:10.1039/c1dt10447k

The hybrid dibismuthines O(CH₂CH₂BiPh ₂)₂ and MeN(CH₂-2-C₆H ₄BiPh₂)₂ react with [M(CO)₅(thf)] (M = Cr or W) to form [{M(CO)₅}₂{O(CH₂CH ₂BiPh₂)₂}] and [{Cr(CO)₅} ₂{MeN(CH₂-2-C₆H₄BiPh ₂)₂}] containing bridging bidentate (Bi₂) coordination. The unsymmetrical tertiary bismuthine complexes [M(CO) ₅{BiPh₂(o-C₆H₄OMe)}] are also described. Depending upon the molar ratio, the hybrid distibines O(CH ₂CH₂SbMe₂)₂ and MeN(CH ₂-2-C₆H₄SbMe₂)₂ react with [M(CO)₅(thf)] to give the pentacarbonyl complexes [{M(CO) ₅}₂{O(CH₂CH₂SbMe₂) ₂}] and [{Cr(CO)₅}₂{MeN(CH₂-2-C ₆H₄SbMe₂)₂}] or tetracarbonyls cis-[M(CO)₄{O(CH₂CH₂SbMe₂) ₂}] and cis-[M(CO)₄{MeN(CH₂-2-C ₆H₄SbMe₂)₂}]. The latter can also be obtained from [Cr(CO)₄(nbd)] or [W(CO)₄(pip) ₂], and contain chelating bidentates (Sb₂-coordinated) as determined crystallographically. S(CH₂-2-C₆H ₄SbMe₂)₂ coordinates as a tridentate (SSb ₂) in fac-[M(CO)₃{S(CH₂-2-C₆H ₄SbMe₂)₂}] (M = Cr or Mo) and fac-[Mn(CO) ₃{S(CH₂-2-C₆H₄SbMe₂) ₂}][CF₃SO₃]. Fac-[Mn(CO) ₃{MeN(CH₂-2-C₆H₄SbMe ₂)₂}][CF₃SO₃] contains NSb ₂-coordinated ligand in the solid state, but in solution a second species, Sb₂-coordinated and with a κ¹-CF ₃SO₃ replacing the coordinated amine is also evident. X-ray crystal structures were also determined for fac-[Cr(CO) ₃{S(CH₂-2-C₆H₄SbMe₂) ₂}], fac-[Mn(CO)₃{S(CH₂-2-C₆H ₄SbMe₂)₂}][CF₃SO₃] and fac-[Mn(CO)₃{MeN(CH₂-2-C₆H₄SbMe ₂)₂}] [CF₃SO₃]. Hypervalent N...Sb interactions are present in cis-[M(CO)₄{MeN(CH ₂-2-C₆H₄SbMe₂)₂}] (M = Mo or W), but absent for M = Cr.

Full text of DOI:10.1039/c1dt10447k

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PAPER
Hybrid dibismuthines and distibines as ligands towards transition metal
carbonyls†
Sophie L. Benjamin, William Levason,* Gillian Reid and Michael C. Rogers
Received 16th March 2011, Accepted 12th April 2011
DOI: 10.1039/c1dt10447k
The hybrid dibismuthines O(CH2CH2BiPh2)2 and MeN(CH2-2-C6H4BiPh2)2 react with [M(CO)5(thf)]
(M = Cr or W) to form [{M(CO)5}2{O(CH2CH2BiPh2)2}] and [{Cr(CO)5}2{MeN(CH2-2-C6H4BiPh2)2}]
containing bridging bidentate (Bi2) coordination. The unsymmetrical tertiary bismuthine complexes
[M(CO)5{BiPh2(o-C6H4OMe)}] are also described. Depending upon the molar ratio, the hybrid
distibines O(CH2CH2SbMe2)2 and MeN(CH2-2-C6H4SbMe2)2 react with [M(CO)5(thf)] to give the
pentacarbonyl complexes [{M(CO)5}2{O(CH2CH2SbMe2)2}] and [{Cr(CO)5}2{MeN(CH2-2-C6H4-
SbMe2)2}] or tetracarbonyls cis-[M(CO)4{O(CH2CH2SbMe2)2}] and cis-[M(CO)4{MeN(CH2-2-C6H4-
SbMe2)2}]. The latter can also be obtained from [Cr(CO)4(nbd)] or [W(CO)4(pip)2], and contain
chelating bidentates (Sb2-coordinated) as determined crystallographically. S(CH2-2-C6H4SbMe2)2
coordinates as a tridentate (SSb2) in fac-[M(CO)3{S(CH2-2-C6H4SbMe2)2}] (M = Cr or Mo) and fac-
[Mn(CO)3{S(CH2-2-C6H4SbMe2)2}][CF3SO3]. Fac-[Mn(CO)3{MeN(CH2-2-C6H4SbMe2)2}][CF3SO3]
contains NSb2-coordinated ligand in the solid state, but in solution a second species, Sb2-coordinated
1
and with a k -CF3SO3 replacing the coordinated amine is also evident. X-ray crystal structures were also
determined for fac-[Cr(CO)3{S(CH2-2-C6H4SbMe2)2}], fac-[Mn(CO)3{S(CH2-2-C6H4SbMe2)2}][CF3-
SO3] and fac-[Mn(CO)3{MeN(CH2-2-C6H4SbMe2)2}] [CF3SO3]. Hypervalent N ◊ ◊ ◊ Sb interactions are
present in cis-[M(CO)4{MeN(CH2-2-C6H4SbMe2)2}] (M = Mo or W), but absent for M = Cr.
with O, N, P etc. donor atoms,1,7 although characterisation of
Introduction
complexes of the last group are poor by current standards. The
Detailed studies of the antimony donor ligands (stibines) carried
only complexes of a tridentate stibine are with the tripodal
MeC(CH2SbPh2)3.8
out in the last 25 years or so, have shown a significantly
different chemistry to that of their lighter analogues, phosphines
and arsines.1 This is clearly demonstrated by the key work of
Werner2 who prepared the first examples of bridging ER3 (E =
P, As, Sb) ligands with SbiPr3, and showed that metathesis
with PR3 or AsR3 led to examples of these as bridging ligands,
although the latter complexes cannot be obtained directly.2 It
is also clear that the organometallic chemistry supported by
tertiary stibines is significantly different to that of the lighter
analogues.1 Although there is an extensive organic chemistry
of bismuth,3 bismuthine ligands have been very little studied,
partly due to their weak s-donor power and to the reactive
C–Bi bonds which are prone to fission in the presence of
some metals.1 The majority of bismuthine complexes are with
metal carbonyls and contain only symmetrical monodentate BiR3
ligands;1,4,5 only one dibismuthine, p-Ph2BiC6H4BiPh2, has been
complexed (with Cr and W carbonyls),6 and there are a few
hybrid ligands containing one bismuthine function in combination
We have recently reported the synthesis of a series of new ligands
(L) containing two bismuthine or stibine groups in combination
with a single O, N or S donor atom, viz O(CH2CH2ER2)2
(E = Sb or Bi, R = Ph; E = Sb, R = Me), MeN(CH2-2-
C6H4ER2)2 and S(CH2-2-C6H4ER2)2 (E = Sb or Bi, R = Me or
5
Ph).9–11 Complexation of these ligands with the [(h -Cp)Fe(CO)2]+
acceptor unit showed coordination only via one Bi or Sb to each
iron centre, to give bridging bidentate coordination, although
hypervalent N(O) ◊ ◊ ◊ Bi(Sb) interactions were present in some, but
not all examples.11 Hypervalency involving the heavier group 15
atoms is currently a very active research topic.12 In this companion
paper we report complexes of these ligands with chromium,
tungsten and manganese carbonyl moieties which illustrate the
ligands functioning in bridging bidentate, chelating bidentate
or chelating tridentate modes. In contrast to the reactions with
5
[(h -Cp)Fe(CO)2]+, for which only one coordination mode was
identified across all the ligand types (although the bismuthine
complexes were less stable than the stibines), the present study
has established markedly different behaviour by ligands involving
Sb or Bi donor groups, and provided examples where the lighter
heteroatom also coordinates.
School of Chemistry, University of Southampton, Southampton, UK, SO17
1BJ. E-mail: wxl@soton.ac.uk
† CCDC reference numbers 817769–817775. For crystallographic data in
CIF or other electronic format see DOI: 10.1039/c1dt10447k
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producing mixtures of tetra- and penta-carbonyl species from
stoichiometric quantities of reagents, but excess metal reagent
led to [{W(CO)5}2{O(CH2CH2SbPh2)2}], containing W(CO)6 as
the only significant impurity. The reactions of MeN(CH2-2-
C6H4SbMe2)2 with [M(CO)5(thf)] followed a similar course, but it
was not possible to produce clean samples of the pentacarbonyls
by using excess metal reagent. The pure tetracarbonyl complexes
were made by a different route (below) and whilst the spectroscopic
identification of the pentacarbonyls as [{M(CO)5}2{MeN(CH2-
2-C6H4SbMe2)2}] is not in doubt, they are not described
further.
Results and discussion
The aim of this study was to elucidate the range of structural types
formed by metal carbonyl complexes of the hybrid ligands, and
therefore the different metal carbonyl fragments are discussed in
turn.
Pentacarbonyls
The pentacarbonyl-chromium and -tungsten complexes,‡
[{M(CO)5}2{O(CH2CH2BiPh2)2}] (M = Cr or W), were readily
prepared by photolysis of M(CO)6 in thf to form [M(CO)5(thf)]
in situ, followed by reaction with 0.5 mol. equivalents of
O(CH2CH2BiPh2)2. The formulation as ligand bridged dimers
with the bismuth donors bonded to C4v pentacarbonyl metal
units follows from the spectroscopic data which showed three
Attempts to grow crystals of the pentacarbonyl complexes for
X-ray study failed, due to slow decomposition of the complexes
in solution.§ This leaves unanswered the question of hypervalent
5
interactions in this series; in the [{(h -Cp)Fe(CO)2}2(L)]2+ species
hypervalent interaction between the heteroatom and one Sb centre
in the solid state was established in several cases from the X-ray
structures,11 and was also evident from the presence of additional
carbonyl stretching vibrations, reflecting the inequivalence of
the iron centres. In solution the inequivalence was no longer
observed, suggesting loss of any significant interaction. In the
pentacarbonyl complexes, there was no evidence for inequivalence
of the metal centres in the IR spectra obtained from Nujol mulls.
Since symmetrical hypervalent interactions involving both metal
centres are ruled out on steric grounds, we conclude that if any
hypervalent interactions are present involving one Sb/Bi donor,
they are insufficient to produce discernable splittings in the IR
spectra.
carbonyl stretching modes in the IR spectra (theory 3; 2a1
+
e), and two carbonyl resonances in the 13C{ H} NMR spectra
at similar frequencies to those in [M(CO)5(BiPh3)].5 The complex
[{Cr(CO)5}2{O(CH2CH2BiPh2)2}] was the only one identified in
the chromium system, but for tungsten, if less than a 2 : 1 mol.
ratio of metal : ligand was used, varying amounts of a second
complex were present. Although this was not isolated in a
1
1
1
pure state, the H and 13C{ H} NMR spectra showed it to be
1
[W(CO)5{k -O(CH2CH2BiPh2)2}]; notably there was no evidence
for a tetracarbonyl species as found in the antimony analogues
(see below).
We also prepared [M(CO)5{BiPh2(o-C6H4OMe)}] (M = Cr or
W) by analogous routes, which have very similar spectroscopic
properties, but are both rare examples of complexes of an
unsymmetrical tertiary bismuthine (BiR2R¢),1 and serve as com-
parators for the hybrid ligand complexes. The ligand MeN(CH2-
2-C6H4BiPh2)2 formed an orange-brown [{Cr(CO)5}2{MeN(CH2-
2-C6H4BiPh2)2}]; again the spectroscopic data (Experimental
section) show pentacarbonylchromium units bridged by bismuth-
coordinated ligand, and with the amine function uncoordinated.
In contrast, repeated attempts to isolate a pure sample of
[{W(CO)5}2{MeN(CH2-2-C6H4BiPh2)2}] failed. Although spec-
troscopic data showed the complex to be the major species
initially formed from reaction of the ligand and two equivalents
of [W(CO)5(thf)], the solutions darkened rapidly due to decompo-
sition, including reformation of much W(CO)6.
The reactions of O(CH2CH2SbMe2)2 with [M(CO)5(thf)] in
a 1 : 2 mol. ratio unexpectedly produced mixtures of the
[{M(CO)5}2{O(CH2CH2SbMe2)2}] and tetracarbonyl complexes
[M(CO)4{O(CH2CH2SbMe2)2}]. The tetracarbonyls were ob-
tained pure by a different route (below), but small amounts
could also be separated from the mixtures by crystallisation
at -18 ◦C. Using a higher M : L ratio, typically ~3 mol.
equivalents of [M(CO)5(thf)] to 1 of O(CH2CH2SbMe2)2, gave
[{M(CO)5}2{O(CH2CH2SbMe2)2}] after work-up, essentially free
of tetracarbonyl species, although some M(CO)6 impurity (M =
W u(CO) = 1976 cm-1, d(13C) = 192, M = Cr u(CO) = 1980
cm-1, d(13C) = 213) remained, hindering microanalysis (other-
wise the complexes were spectroscopically pure). The ligand
O(CH2CH2SbPh2)2 behaved similarly to the methyl analogue in
Tetracarbonyls
The reaction of [M(CO)5(thf)] (M
= Cr or W) with
O(CH2CH2SbMe2)2 or MeN(CH2-2-C6H4SbMe2)2 in a £1 : 1
mol. ratio gave mainly [M(CO)4(ligand)], with smaller amounts
of pentacarbonyl complexes. Reaction of the ligands with
[Cr(CO)4(nbd)] (nbd = norbornadiene) or [W(CO)4(pip)2] (pip =
piperidine) afforded the pure tetracarbonyl complexes directly. In
contrast, as noted above, the hybrid bismuthine ligands did not
produce any tetracarbonyl species on reaction with [M(CO)5(thf)],
and they also failed to react with the tetracarbonyl precursors,
probably due to the weak donor power of the bismuthine units.
Only a few bismuthine complexes are known,1 and all contain a
single bismuthine donor on the metal centre. The ready formation
of [M(CO)4(hybrid distibine)] complexes was unexpected since
the chelate rings formed are large, 10-membered for MeN(CH2-
2-C6H4SbMe2)2 and 8-membered for O(CH2CH2SbMe2)2, and
therefore no strong chelate effect is expected. It is possible that
hypervalent interactions may promote some pre-organisation of
the ligands towards chelation. Group 6 tetracarbonyl complexes
are known with distibines giving rise to 5- (o-C6H4(SbMe2)2),13
6- (R2Sb(CH2)3SbR2),14 and 7-membered (o-C6H4(CH2SbMe2)2)15
rings. Distibinomethane ligands (R2SbCH2SbR2) form dinuclear
complexes [{M(CO)4}2(R2SbCH2SbR2)2] with distibine bridges in
8-membered rings.16
Crystal structures of four examples with the hybrid lig-
ands were determined: [M(CO)4{O(CH2CH2SbMe2)2}] (M = Cr
‡ Molybdenum carbonyl complexes with bismuthine ligands are often
much less stable than chromium or tungsten analogues4–6 and were not
generally included in the present study.
§ In some cases crystals of the corresponding tetracarbonyl complex or
M(CO)6 resulted.
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Fig. 1 Structure of [Cr(CO)4{O(CH2CH2SbMe2)2}] showing the atom
labelling scheme. There is disorder in the Sb ligand backbone which was
modelled as two conformations (A/B) with A being shown. Ellipsoids are
drawn at the 40% probability level and H atoms are omitted for clarity.
Fig. 3 Structure of [Cr(CO)4{MeN(CH2-2-C6H4SbMe2)2}] showing the
atom labelling scheme. Ellipsoids are drawn at the 50% probability level
and H atoms are omitted for clarity.
Table 1 Selected bond lengths (A) and angles (◦) for [Cr(CO)4-
˚
{O(CH2CH2SbMe2)2}]
Cr1–C9
Cr1–C11
Cr1–Sb1
Sb1 ◊ ◊ ◊ O1A
C10–Cr1–C12
C12–Cr1–C11
C12–Cr1–C9
C11–Cr1–Sb2
C10–Cr1–Sb1
C9–Cr1–Sb1
1.895(11)
1.890(11)
2.601(2)
3.06(2)
88.9(6)
90.7(5)
91.0(5)
90.5(3)
88.5(4)
90.2(3)
Cr1–C10
Cr1–C12
Cr1–Sb2
Sb2 ◊ ◊ ◊ O1A
C10–Cr1–C11
C10–Cr1–C9
C12–Cr1–Sb2
C9–Cr1–Sb2
C11–Cr1–Sb1
Sb2–Cr1–Sb1
1.833(11)
1.842(12)
2.588(2)
2.86(2)
90.3(5)
91.8(5)
89.9(5)
87.4(3)
88.3(3)
92.69(5)
Table 2 Selected bond lengths (A) and angles (◦) for [W(CO)4-
{O(CH2CH2SbMe2)2}]
˚
Fig. 2 Structure of [W(CO)4{O(CH2CH2SbMe2)2}] showing the atom
labelling scheme. There is disorder in the Sb ligand backbone which was
modelled as two conformations (A/B) with A being shown. Ellipsoids are
drawn at the 40% probability level and H atoms are omitted for clarity.
W1–C9
2.026(14)
1.94(2)
2.7250(14)
3.44(2)
88.6(8)
91.5(6)
89.3(6)
87.8(4)
88.9(5)
88.1(4)
W1–C10
W1–C12
2.00(2)
2.04(2)
2.7378(13)
3.16(2)
91.2(6)
90.7(6)
90.5(5)
90.3(4)
91.3(4)
92.03(4)
W1–C11
W1–Sb1
W1–Sb2
Sb1 ◊ ◊ ◊ O1A
C11–W1–C10
C10–W1–C9
C10–W1–C12
C9–W1–Sb1
C11–W1–Sb2
C12–W1–Sb2
SB2 ◊ ◊ ◊ O1A
C11–W1–C9
C11–W1–C12
C10–W1–Sb1
C12–W1–Sb1
C9–W1–Sb2
Sb1–W1–Sb2
or W) which are isomorphous, and [M(CO)4{MeN(CH2-2-
C6H4SbMe2)2}] (Fig. 1 to 4, Tables 1 to 4). The coordination envi-
ronments in [M(CO)4{MeN(CH2-2-C6H4SbMe2)2}], are similar to
that in the molybdenum analogue reported earlier,9 showing a near
to octahedral geometry and M–CtransSb shorter than M–CtransCO
.
Notably, the tungsten complex shows one hypervalent N ◊ ◊ ◊ Sb
˚
interaction to antimony (Sb2 ◊ ◊ ◊ N = 2.997(3) A). This correlates
conformations of the tungsten and chromium complexes (the
molybdenum analogue9 is essentially superimposable on the
tungsten), which reveal that the formation of the hypervalent
interaction in the tungsten complex requires significant changes
in the conformation of the ligand backbone to orientate the
lone pair on the nitrogen appropriately, bringing it closer to one
Sb. In the chromium complex the ligand has a more “folded”
conformation with the lone pair pointing away from the antimony
atoms. In order for the hypervalent interaction to occur, the
energy gain from the N ◊ ◊ ◊ Sb bond must be greater than the
energy needed to reorientate the ligand conformation, and this
subtle balance qualitatively rationalises the occurrence or absence
˚
with a slightly longer W–Sb bond (2.7745(4) A) compared to
˚
W–Sb1 (2.7402(4) A) which lacks any hypervalent interaction
˚
(Sb1 ◊ ◊ ◊ N = 4.055(2) A). This behaviour is similar to that observed
for the molybdenum complex (Mo–Sb1 = 2.7792(5), Mo–Sb2 =
9
˚
2.7509(6), N ◊ ◊ ◊ Sb1 = 3.05 A). However, in the chromium complex
(Table 3), the Cr–Sb bonds do not differ significantly (2.5914(12),
˚
2.5934(12) A). The Sb ◊ ◊ ◊ N distances are also quite similar
˚
(3.467(6), 3.645(6) A) and close to the sum of the Van der Waals
17
˚
radii (3.55 A), which suggests no hypervalent interaction is
present in the chromium system. The availability of structural data
on the three Group 6 carbonyl complexes illustrates the subtleties
surrounding the hypervalent interactions. Fig. 5 shows the
1
of hypervalency in these systems. The 1H and 13C{ H} NMR
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Fig. 4 Structure of [W(CO)4{MeN(CH2-2-C6H4SbMe2)2}] showing the atom labelling scheme. Ellipsoids are drawn at the 50% probability level and H
atoms are omitted for clarity.
Table 3 Selected bond lengths (A) and angles (◦) for [Cr(CO)4-
˚
{MeN(CH2-2-C6H4SbMe2)2}]
Cr1–C20
Cr1–C22
Cr1–Sb1
Sb1 ◊ ◊ ◊ N1
C21–Cr1–C22
C22–Cr1–C23
C22–Cr1–C20
C23–Cr1–Sb2
C22–Cr1–Sb1
C20–Cr1–Sb1
1.902(8)
1.859(8)
2.5934(12)
3.467(6)
88.7(3)
92.4(3)
92.5(3)
87.5(2)
88.5(2)
90.8(2)
Cr1–C21
Cr1–C23
Cr1–Sb2
Sb2 ◊ ◊ ◊ N1
C21–Cr1–C23
C21–Cr1–C20
C21–Cr1–Sb2
C20–Cr1–Sb2
C23–Cr1–Sb1
Sb2–Cr1–Sb1
1.835(8)
1.862(8)
2.5914(12)
3.643(6)
92.1(3)
91.1(3)
87.9(2)
87.8(2)
86.2(3)
94.84(4)
Fig.
5
The conformations present in [W(CO)4{MeN(CH2-2-
C6H4SbMe2)2}] (left) and [Cr(CO)4{MeN(CH2-2-C6H4SbMe2)2}]
(right) as a consequence of the presence and absence of hypervalent
interactions.
Table 4 Selected bond lengths (A) and angles (◦) for [W(CO)4-
{MeN(CH2-2-C6H4SbMe2)2}]
˚
W1–C20
W1–C22
W1–Sb1
Sb1 ◊ ◊ ◊ N1
C22–W1–C21
C21–W1–C23
C21–W1–C20
C23–W1–Sb1
C21–W1–Sb2
C20–W1–Sb2
2.035(3)
1.976(3)
2.7402(4)
4.055(2)
89.15(13)
90.95(12)
93.09(12)
89.30(9)
87.20(9)
84.67(9)
W1–C21
W1–C23
W1–Sb2
Sb2 ◊ ◊ ◊ N1
C22–W1–C23
C22–W1–C20
C22–W1–Sb1
C20–W1–Sb1
C23–W1–Sb2
Sb1–W1–Sb2
1.978(3)
2.032(3)
2.7745(4)
2.997(3)
86.68(12)
90.88(12)
89.30(9)
86.59(9)
98.03(8)
94.325(14)
distances are unreliable. Tetracarbonyl complexes with S(CH2-2-
C6H4SbMe2)2 were not isolated.
Tricarbonyls
The chemistry of these hybrid ligands described thus far,9–11 and
above, showed a preference for coordination only via the antimony
or bismuth donor atoms. We were interested to explore whether
it would be possible to coordinate the lighter heteroatoms (O,
N or S) in tandem, hence leading to tridentate coordination and
disparate donor properties. To this end, S(CH2-2-C6H4SbMe2)2
was reacted with [M(CO)3(MeCN)3]18 (M = Cr or Mo), the nitrile
being substituted cleanly at room temperature in MeCN solution.
However, no reaction occurred with S(CH2-2-C6H4BiR2)2 under
similar conditions, and under reflux the hybrid bismuthine ligands
fragmented. The structure of [Cr(CO)3{S(CH2-2-C6H4SbMe2)2}]
(Fig. 6, Table 5) shows the expectedfac-octahedral geometry which
maximises the Cr–CO bonding; notably the Cr–C and Cr–Sb dis-
tances differ little from those in [Cr(CO)4{O(CH2CH2SbMe2)2}].
spectra do not show any inequivalence of the antimony groups
for either complex in solution; either the hypervalency in the
tungsten complex is lost in solution (as in most of the complexes
with [CpFe(CO)2]+)11 or the effects are too small to resolve. For a
cis tetracarbonyl, four IR active carbonyl vibrations are expected
irrespective of any hypervalent contact, so IR spectroscopy does
not help in this case.
The structures of the two [M(CO)4{O(CH2CH2SbMe2)2}] (M =
Cr or W) show similar trends in the M–C distances. Unfortunately,
both show disorder in the -CH2CH2OCH2CH2- unit, and although
this was relatively successfully modeled over two sites, the Sb ◊ ◊ ◊ O
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Fig. 7 Structure of [Mn(CO)3{S(CH2-2-C6H4SbMe2)2}]+ showing the
atom labelling scheme. Ellipsoids are drawn at the 50% probability level
1
Fig. 6 Structure of [Cr(CO)3{S(CH2-2-C6H4SbMe2)2}] showing the atom
labelling scheme. Ellipsoids are drawn at the 50% probability level and H
atoms are omitted for clarity.
and H atoms are omitted for clarity. Symmetry operation: a = x, - y, z.
2
◦
˚
Table 5 Selected bond lengths (A) and angles ( ) for [Cr(CO)3{S(CH2-2-
C6H4SbMe2)2}]
Cr1–C19
Cr1–C21
Cr1–Sb1
C21–Cr1–C20
C20–Cr1–C19
C19–Cr1–S1
C20–Cr1–Sb1
C20–Cr1–Sb2
S1–Cr1–Sb2
1.842(4)
1.835(4)
2.5982(6)
90.5(2)
Cr1–C20
Cr1–S1
Cr1–Sb2
C21–Cr1–C19
C21–Cr1–S1
C21–Cr1–Sb1
S1–Cr1–Sb1
C19–Cr1–Sb2
Sb1–Cr1–Sb2
1.838(4)
2.4114(11)
2.5985(6)
87.0(2)
86.77(12)
90.16(12)
88.73(3)
88.20(12)
94.72(2)
91.9(2)
91.69(12)
87.58(12)
94.01(11)
88.99(3)
Fig. 8 Structure of [Mn(CO)3{MeN(CH2-2-C6H4SbMe2)2}]+ showing
the atom labelling scheme. Ellipsoids are drawn at the 50% probability
level and H atoms are omitted for clarity.
The 1H and 13C{ H} NMR spectra show the [M(CO)3{S(CH2-2-
C6H4SbMe2)2}] (M = Cr or Mo) are stable in solution in CH2Cl2,
and both show two d(Me) resonances of equal intensity, reflecting
the MeSb- groups syn to CO and syn to S respectively. The solution
IR spectra in CH2Cl2 show one sharp and one very broad stretch,
which correspond to the a1 + e modes of the fac-tricarbonyl
unit, the broadening of the e mode reflecting the lower actual
symmetry (Cs), although splitting (into a¢ + a¢¢) was not clearly
resolved. Curiously, both complexes show four carbonyl stretches
in the Nujol mull IR spectra, which is attributed to a solid state
effect, since the spectra are unchanged after recrystallisation of
the complexes and the effect is not present in solution.
1
◦
˚
Table 6 Selected bond lengths (A) and angles ( ) for [Mn(CO)3{S(CH2-
1
2
2-C6H4SbMe2)2}][CF3SO3]. Symmetry operation: a = x, - y, z
Mn1–C10
Mn1–Sb1
C11–Mn1–C10
C10–Mn1–S1
C10–Mn1–Sb1
Sb1–Mn1–Sb1a
1.822(3)
2.5716(4)
90.32(11)
88.54(8)
86.52(8)
94.45(2)
Mn1–C11
Mn1–S1
C10–Mn1–C10a
C11–Mn1–Sb1
S1–Mn1–Sb1
1.788(4)
2.3649(11)
92.5(2)
89.88(8)
91.23(2)
In order to probe the potential for these hybrid ligands
towards tridentate coordination more broadly, we have also
investigated their chemistry with the fac-[Mn(CO)3]+ frag-
◦
˚
Table 7 Selected bond lengths (A) and angles ( ) for [Mn(CO)3-
{MeN(CH2-2-C6H4SbMe2)2}][CF3SO3]
ment. The reactions of S(CH2-2-C6H4SbMe2)2 or MeN(CH2-
Mn1–C20
Mn1–C22
Mn1–Sb1
C20–Mn1–C22
C22–Mn1–C21
C21–Mn1–N1
C21–Mn1–Sb2
C20–Mn1–Sb1
N1–Mn1–Sb1
1.797(9)
1.806(9)
2.5656(13)
89.5(4)
90.5(4)
91.1(3)
88.6(3)
86.3(3)
91.1(2)
Mn1–C21
Mn1–N1
Mn1–Sb2
C20–Mn1–C21
C20–Mn1–N1
C22–Mn1–Sb2
N1–Mn1–Sb2
C22–Mn1–Sb1
Sb2–Mn1–Sb1
1.817(9)
2.236(6)
2.5628(14)
89.3(4)
91.9(3)
88.2(3)
90.5(2)
87.4(3)
95.64(4)
19
2-C6H4SbMe2)2 with [Mn(CO)3(Me2CO)3][CF3SO3]
in ace-
tone solution, followed by recrystallisation from CH2Cl2,
gave yellow [Mn(CO)3{S(CH2-2-C6H4SbMe2)2}][CF3SO3] and
[Mn(CO)3{MeN(CH2-2-C6H4SbMe2)2}][CF3SO3] (the latter was
briefly mentioned in our earlier study9), but attempts to obtain
a similar complex with O(CH2CH2SbMe2)2 failed, presumably
due to the weak affinity of the ether oxygen donor for the soft
manganese centre. Crystal structures of the two complexes were
determined (Fig. 7 and 8, Tables 6 and 7) and show the expected
facial isomers. The geometries are close to octahedral and the
Mn–Sb and Mn–CtransSb distances differ little between the two
species, (fac-[Mn(CO)3{S(CH2-2-C6H4SbMe2)2}][CF3SO3] adopts
crystallographic m symmetry with the Mn, S and one CO ligand
occupying the mirror plane).
For fac-[Mn(CO)3{S(CH2-2-C6H4SbMe2)2}][CF3SO3] the solu-
tion IR, H and 13C{ H} NMR spectra are consistent with the
1
1
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solid state structure, confirming its retention in solution. However,
were obtained using a VG Biotech platform. Preparations were
undertaken using standard Schlenk and glove box techniques
under a dry N2 atmosphere. Solvents were dried by distillation
from CaH2 (CH2Cl2) or Na/benzophenone ketyl (thf, hexane and
diethyl ether). Photochemical syntheses were carried out using a
125 W medium pressure mercury lamp (Photochemical Reactors
Ltd.) emitting at 365 nm.
1
careful examination of the 1H and 13C{ H} NMR spectra of
fac-[Mn(CO)3{MeN(CH2-2-C6H4SbMe2)2}]CF3SO3 reveal that a
second (similar) species is present even in non-coordinating
solvents like CH2Cl2 and CHCl3. This results in two distinct
sets of resonances. There are also two closely spaced 19F NMR
resonances due to coordinated and ionic triflate. The major
species is clearly the cation found in the crystal structure and
The O(CH2CH2SbR2)2 (R = Me or Ph),10 O(CH2CH2BiPh2)2,11
BiPh2(o-C6H4OMe),7 MeN(CH2-2-C6H4SbMe2)2,9 MeN(CH2-
2-C6H4BiR2)2,11 S(CH2-2-C6H4SbMe2)2, S(CH2-2-C6H4BiR2)2,11
2
the second complex is assigned as [Mn(CO)3{k -MeN(CH2-2-
1
C6H4SbMe2)2}(k -CF3SO3)] where the relatively weakly bound
1
tertiary amine has been replaced by a k -coordinated triflate.
[M(CO)5(thf)] (M =
Cr, W),20 [Cr(CO)4(nbd)],21 [W(CO)4-
(pip)2],22 [M(CO)3(MeCN)3]18 (M = Cr, Mo) and [Mn(CO)3-
(acetone)3][CF3SO3]19 were made as described.
Conclusions
The metal pentacarbonyl dibismuthines reported here confirm
that metal complexes with different substituents at the bismuth
centre may be formed (as do the analogues with BiPh2(o-
C6H4OMe)), whereas almost all other well characterised examples
contained symmetrically substituted bismuthines (BiR3).1 How-
ever, the weak binding power of bismuth prevents coordination
via more than one bismuth atom per metal centre. A possible
approach to overcome this would be to use dibismuthines with
rigid linkers, pre-organised for chelation–such compounds are not
known at present.
[Cr(CO)5{Ph2Bi(o-C6H4OMe)}]
Cr(CO)6 (0.3 g, 1.36 mmol) was dissolved in thf (40 mL) and the
solution photolysed for 1 h, producing a bright orange solution.
Ph2Bi(o-C6H4OMe) (0.64 g, 1.36 mmol), dissolved in thf (10 mL)
was added and the mixture stirred for 45 min. The solvent was
removed in vacuo, leaving a yellow/brown residue. The addition
of hexane (20 mL) gave a yellow solution and some darker solids,
which were removed by filtration. The solvent was again removed
in vacuo, yielding a bright yellow solid (0.26 g, 29%). Required
for C24H17BiCrO6: C, 43.5; H, 2.6. Found: C, 44.0; H, 2.5%.
IR (CH2Cl2/cm-1): 2064w, 1980 m, 1945s; (Nujol/cm-1): 2062w,
The hybrid tridentates containing antimony provide rare ex-
amples of polydentate stibine complexes, and also establish a
wider range of coordination modes including bridging bidentate,
chelating bidentate (both Sb2-coordinated) and chelating triden-
tate (Sb2S- or Sb2N-coordinated). The failure to obtain tridentate
coordination from ligands with an ether oxygen in the backbone
reflects the very poor affinity of this group for low valent metal
centres. Particularly notable are the complexes exhibiting hyper-
1
1985w, 1947s. H NMR (CD2Cl2): d 3.79 ([3H], s, OMe), 6.82–
1
7.65 ([14H], m, aromatic). 13C{ H} NMR (CD2Cl2, 253 K): d 55.3
(OMe), 110.1, 123.1, 129.1, 130.0, 130.3, 135.8, 136.0, 140.1, 161.0
(Caromatic), 217.0 (4CO), 222.7 (CO). MS (FAB): m/z = 662 [M]+,
606 [M - 2CO]+, 550 [M - 4CO]+, 522 [M - 5CO]+.
[W(CO)5{Ph2Bi(o-C6H4OMe)}]
2
valency. In the three Group 6 complexes [M(CO)4{k -MeN(CH2-
2-C6H4SbMe2)2}], hypervalent interactions between N and one Sb
are clearly present in the Mo9 and W species, but absent from the
Cr complex. This can be rationalised as a trade-off between the
small energy gain from the extra N ◊ ◊ ◊ Sb bonding interaction and
the energy needed to achieve the ligand conformation necessary to
bring the N and Sb into the correct orientation. These complexes,
together with the Fe species described in our earlier paper,11
provide rare examples in which a single Sb (or Bi) atom behaves
as a donor to a transition metal atom and an acceptor to a lighter
heteroatom simultaneously.
W(CO)6 (0.41 g, 1.17 mmol) was dissolved in thf (40 mL) and
the solution photolysed for 1 h, producing a dark yellow solution.
Ph2Bi(o-C6H4OMe) (0.44 g, 0.93 mmol, dissolved in thf (10 mL)
was added and the mixture stirred for 1 h. The solvent was removed
in vacuo, leaving a dark brown residue. Extraction with hexane
(20 mL) and removal of all solvents gave a yellow/brown solid. A
second extraction with hexane (20 mL), followed by removal of the
solvent, precipitated a pale yellow solid (0.12 g, 16%). Required
for C24H17BiO6W: C, 36.3; H, 2.2. Found: C, 36.0; H, 2.0%. IR
(CH2Cl2/cm-1): 2074s, 1976s, 1944s; (Nujol/cm-1): 2070s, 1981s,
1945s. 1H NMR (CD2Cl2): d 3.78 ([3H], s, OMe), 6.90–7.53 ([14H],
1
m, PhBi). 13C{ H} NMR (CD2Cl2, 253 K): d 56.0 (OMe), 110.9,
Experimental
123.6, 129.8, 130.1, 130.8, 136.3, 136.6, 139.3, 161.7 (Caromatic), 198.1
(1JWC = 126 Hz, 4CO), 199.2 (1JWC = 181 Hz, CO). MS (FAB): m/z =
794 [M]+, 738 [M - 2CO]+.
Infrared spectra were recorded as Nujol mulls between NaCl
plates using a Perkin Elmer Spectrum 100 spectrometer over the
range 4000–600 cm-1 and solution spectra used NaCl solution
cells over the range 2200–1800 cm-1. 1H NMR spectra were
recorded from CD2Cl2 or CDCl3 solutions using a Bruker AV300
[{Cr(CO)5}2{O(CH2CH2BiPh2)2}]
1
spectrometer and low temperature 1H and 13C{ H} NMR spectra
Cr(CO)6 (0.20 g, 0.91 mmol) was dissolved in thf (40 mL) and
the solution irradiated for 1 h, producing an orange solution.
O(CH2CH2BiPh2)2 (0.29 g, 0.36 mmol) dissolved in thf (10 mL)
was added and the mixture stirred for 45 min. The solvent was
removed in vacuo, leaving an orange/brown solid which was
redissolved in hexane (20 mL) and filtered to remove insoluble
dark impurities. The solvent was removed from the filtrate, yielding
the complex as viscous yellow/orange oil (0.14 g, 33%). Required
of the complexes were recorded from CDCl3 or CD2Cl2 solutions
using a Bruker DPX400 spectrometer and are referenced to the
protio-solvent signal. 55Mn NMR spectra were obtained on the
Bruker DPX400 spectrometer and are referenced to aqueous
KMnO4. Microanalyses on new complexes were undertaken by
Medac Ltd. FAB mass spectra were obtained using 3-NOBA
as matrix from Medac Ltd and electrospray (ES+) mass spectra
6570 | Dalton Trans., 2011, 40, 6565–6574
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for C38H28Bi2Cr2O11: C, 38.6; H, 2.4. Found: C, 39.5; H, 2.5%. IR
(CH2Cl2/cm-1): 2063s, 1980s, 1942s; (Nujol/cm-1): 2063m, 1985w,
[{W(CO)5}2{O(CH2CH2SbPh2)2}]
W(CO)6 (0.35 g, 1.00 mmol) was dissolved in thf (40 mL) and
photolysed for 1 h, producing a dark yellow solution. A solution
of O(CH2CH2SbPh2)2 (0.25 g, 0.40 mmol) in thf (10 mL) was
added and the mixture stirred for 2.5 h at room temperature. All
volatiles were removed in vacuo leaving a yellow/brown residue.
Hexane (20 mL) was added and the mixture stirred for 10 min at
which point most of the solids dissolved. The yellow solution
was then filtered and the solvent removed in vacuo to yield a
brown solid (0.13 g, 27%). IR (CH2Cl2/cm-1): 2071m, 1976, 1941s;
(Nujol/cm-1): 2071w, 1981w, 1944s. 1H NMR (CDCl3): d 2.39 (4H,
1
3
1946s. H NMR (CD2Cl2): d 2.87 ([4H], t, JHH = 7 Hz, CH2Bi),
3
4.00 ([4H], t, JHH = 7 Hz, CH2O), 7.30–7.71 ([20H], m, PhBi).
1
13C{ H} NMR (CD2Cl2, 253 K): d 27.8 (CH2Bi), 68.2 (CH2O),
129.2, 130.1, 135.7 (Caromatic), 217.2 (4CO), 222.4 (CO). MS (FAB):
m/z = 1051 [M + Na - 2Ph]+.
[{W(CO)5}2{O(CH2CH2BiPh2)2}]
W(CO)6 (0.18 g, 0.51 mmol) was dissolved in thf (40 mL) and
the solution photolysed for 1 h, producing a dark yellow solution.
O(CH2CH2BiPh2)2 (0.16 g, 0.20 mmol) dissolved in thf (10 mL)
was added and the mixture stirred at room temperature for
45 min. The solvent was removed in vacuo, leaving a dark brown
residue. Extraction with hexane (20 mL) and removal of all
volatiles gave a yellow/brown solid (0.05 g, 22%). Required for
C38H28Bi2O11W2·C6H14: C, 34.9; H, 2.8. Found: C, 34.7; H, 2.9%.
IR (CH2Cl2/cm-1): 2073s, 1976s, 1943s; (Nujol/cm-1): 2074m,
t, CH2Sb), 3.65 (4H, t, CH2O), 7.4–7.5 (m, PhSb). 13C{ H} NMR
1
(CDCl3): d 21.4 (CH2Sb), 68.0 (CH2O), 130.0, 130.2, 130.9, 135.3
(Caromatic), 197.0 (1JWC = 124 Hz, 4CO), 199.1 (1JWC = 166 Hz, CO).
[{Cr(CO)5}2{MeN(CH2-2-C6H4BiPh2)2}]
Cr(CO)6 (0.13 g, 0.59 mmol) was dissolved in thf (40 mL) and the
solution photolysed for 1 h, producing a dark orange solution.
MeN(CH2-2-C6H4BiPh2)2 (0.25 g, 0.27 mmol) dissolved in thf
(10 mL) was added and the mixture stirred for 1 h. The solvent was
removed in vacuo, leaving an orange/brown solid. The addition
of hexane (20 mL) gave an orange solution and some darker
solids, which were removed by filtration. Removal of the solvent
from the filtrate gave an orange/brown solid (0.17 g, 48%). IR
(CH2Cl2/cm-1): 2063s, 1980s, 1944s; (Nujol/cm-1): 2063m, 1985s,
1
3
1982s, 1948s. H NMR (CD2Cl2, 253 K): d 2.94 ([4H], t, JHH
=
7 Hz, CH2Bi), 4.00 ([4H], t, 3JHH = 7 Hz, CH2O), 7.24–7.86 ([20H],
m, Ph), (0.88, 1.27, C6H14). 13C{ H} NMR (CD2Cl2, 253 K): d
1
27.2 (CH2Bi), 68.4 (CH2O), 129.2, 130.8, 135.5 (Caromatic), 197.3
(1JWC = 128 Hz, 4CO), 198.0 (1JWC = 180 Hz, CO), (14.4, 23.2,
32.2, nC6H14).
[{W(CO)5}2{O(CH2CH2SbMe2)2}]
1
1946s. H NMR (CD2Cl2, 253 K): d 1.71 ([3H], s, MeN), 3.49
([4H], s, CH2N), 7.0–7.7 ([28H], m, aromatic CH). 13C{ H} NMR
1
W(CO)6 (0.32 g, 0.91 mmol) was dissolved in thf (40 mL), and
photolysed for 1 h, producing a dark yellow solution. A solution
of O(CH2CH2SbMe2)2 (0.137 g, 0.36 mmol) in thf (10 mL) was
added and the mixture stirred for 1.5 h at room temperature. All
volatiles were removed in vacuo leaving a yellow-brown residue.
Hexane (20 mL) was added and the mixture was stirred for 10 min.
The solution was filtered and the filtrate reduced in vacuo to ca.
10 mL, then stored in a freezer (-18 ◦C, 16 h). The off-white
solid deposited was separated by filtration at 0 ◦C and dried
in vacuo (0.11 g, 30%). Required for C18H20O11Sb2W2: C, 21.1; H,
2.0. Found: C, 21.2; H, 2.0%. IR (CH2Cl2/cm-1): 2068s, 1971(sh),
1936s; (Nujol/cm-1): 2066m, 1975s, 1936s. 1H NMR (CDCl3):
d 1.30 ([12H], s, MeSb), 2.12 ([4H], t, CH2Sb), 3.77 ([4H], t,
(CD2Cl2, 253 K): d 41.2 (MeN), 64.7 (CH2N), 127.8, 130.4, 130.7,
131.1, 136.6, 138.0, 140.3, 144.6 (Caromatic), 157.7 and 159.2 (BiCipso),
217.6 (4CO), 222.8 (CO).
[W(CO)4{O(CH2CH2SbMe2)2}]
[W(CO)4(pip)2] (0.12 g, 0.27 mmol) was suspended in toluene
(50 mL) and O(CH2CH2SbMe2)2 (0.10 g, 0.27 mmol) was added.
The mixture was refluxed for 18 h, resulting in a cloudy orange so-
lution. The volatiles were removed in vacuo and dichloromethane
(20 mL) added, resulting in a pale yellow solution and some orange
solid. The solution was isolated by filtration, the volume of the
filtrate reduced in vacuo to ca. 5 mL. Hexane (5 mL) was added
and the solution stored in a freezer (-18 ◦C,16 h), yielding a pale
orange precipitate (0.06 g, 22%). Required for C12H20O5Sb2W: C,
21.5; H, 3.0. Found: C, 21.8; H, 3.1%. IR (CH2Cl2/cm-1): 2009,
1905sh, 1893s, 1871sh; (Nujol/cm-1): 2012s, 1916s, 1896s, 1864sh.
1H NMR (CDCl3): d 1.88 ([6H], s, MeSb), 2.04 ([2H], br t, SbCH2),
1
CH2O). 13C{ H} NMR (CDCl3): d -1.5 (MeSb), 17.6 (CH2Sb),
67.4 (CH2O), 197.4 (1JWC = 124 Hz, 4CO), 200.0 (1JWC = 162 Hz,
CO). MS (FAB): m/z = 1047 [M + Na]+, 1025 [M]+.
[{Cr(CO)5}2{O(CH2CH2SbMe2)2}]
1
3.76 ([2H], br t, CH2O). 13C{ H} NMR (CDCl3): d -0.1 (MeSb),
Cr(CO)6 (0.20 g, 0.91 mmol) was dissolved in thf (40 mL) and
the solution photolysed for 1 h, producing an orange solution.
O(CH2CH2SbMe2)2 (0.137 g, 0.36 mmol) in thf (10 mL) was
added and the mixture stirred for 1.5 h at room temperature. The
solvent was removed in vacuo to leave a yellow/brown residue.
Hexane (20 mL) was added and the mixture stirred for 10 min
at room temperature. The solution was filtered and the solvent
removed in vacuo yielding a bright yellow viscous oil (0.06 g, 22%).
IR (CH2Cl2/cm-1): 2057s, 1979w, 1935s; (Nujol/cm-1): 2057(s),
18.5 (CH2Sb), 68.4 (CH2O), 204.0 (1JWC = 130 Hz, CO), 207.7
(1JWC = 148 Hz, CO). MS (FAB): m/z = 672 [M]+, 588 [M - 3CO]+.
The route using a 1 : 1 ratio of [W(CO)5(thf)] : L yields a mixture
of penta- and tetra-carbonyl complexes. Crystals of the tetra-
carbonyl complex were isolated from this mixture.
[Cr(CO)4{O(CH2CH2SbMe2)2}]
1
1985m, 1938s. H NMR (CDCl3) d 1.21 ([12H], s, MeSb), 2.12
[Cr(CO)4(nbd)] (0.10 g, 0.40 mmol) and Me2Sb(CH2)2-
O(CH2)2SbMe2 (0.15 g, 0.40 mmol) were refluxed overnight in
hexane (50 mL). The volatiles were removed in vacuo and the
resultant yellow residue dissolved in CH2Cl2 (20 mL). The solution
1
([4H], t, CH2Sb), 3.8 ([4H], t, CH2O). 13C{ H} NMR (CDCl3):
d -2.0 (MeSb), 18.2 (CH2Sb), 66.8 (CH2O), 218.5 (4CO), 223.9
(CO).
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was concentrated in vacuo to ca. 5 mL causing precipitation of a
yellow solid (0.04 g, 19%). Required for C12H20CrO5Sb2: C, 26.7; H,
3.7. Found: C, 26.8; H, 3.8%. IR (CH2Cl2/cm-1): 1996s, 1904sh,
solids redissolved in dichloromethane (20 mL). The solution was
filtered and the volume reduced in vacuo to ca. 5 mL. Diethyl
ether (5 mL) was added and the solution was then concentrated
further until it reached clouding point. The Schlenk was then
stored in a freezer (-18 ◦C, 16 h), yielding bright yellow rhombic
crystals (0.04 g, 13%). Required for C21H24CrO3SSb2: C, 38.7; H,
3.7. Found: C, 39.6; H, 3.3%. IR (CH2Cl2/cm-1): 1927s, 1829vbr;
(Nujol/cm-1): 1922s, 1916s, 1827s, 1815s. 1H NMR (CDCl3): d 1.13
([6H], s, MeSb) and 1.36 ([6H s, MeSb), 3.41 ([4H], br m, CH2S),
1
1888s, 1869sh; (Nujol/cm-1): 2000m, 1912m, 1891sh. H NMR
(CDCl3): d 1.12 (12H, s, MeSb), 2.05 (4H, t, CH2Sb), 3.80 (4H,
1
t, CH2O). 13C{ H} NMR (CDCl3): d -1.5 (MeSb), 18.4 (CH2Sb),
67.3 (CH2O), 223.8 (CO), 229.6 (CO). MS (CI): m/z = 540 [M]+.
A mixture of tetra- and penta-carbonyl complexes forms from
the photolysis route using a 1 : 1 ratio of reactants. Crystals of the
tetracarbonyl were grown from a sample made by this route.
1
7.0–7.6 ([8H], m, aromatic CH). 13C{ H} NMR (CDCl3): d 0.9 and
1.7 (MeSb), 45.9 (CH2S), 129.7, 130.2, 130.5, 131.5, 132.3, 140.5
(Caromatic), 230.8 (CO), 233.3 (CO). MS (FAB): m/z = 652 [M]+, 568
[M - 3CO]+.
[W(CO)4{MeN(CH2-2-C6H4SbMe2)2}]
W(CO)6 (0.12 g, 0.35 mmol) was dissolved in thf (40 mL)
and the solution photolysed for 1 h, giving a dark yellow
solution. MeN(CH2-2-C6H4SbMe2)2 (0.15 g, 0.29 mmol) dissolved
in CH2Cl2 (10 mL) was added and the reaction mixture stirred for
2 h. The solvent was removed invacuo leavingadark brown residue.
Extraction with hexane (20 mL) produced a yellow solution and
residual brown solid, which was removed by filtration. Storage
of the hexane solution (4 ◦C, 16 h) gave the complex as yellow
crystalline blocks (0.15 g, 63%). Required for C23H27NO4Sb2W:
C, 34.2; H, 3.4; N, 1.7. Found: C, 34.4; H, 3.3; N, 1.7%. IR
(CH2Cl2/cm-1): 2011s, 1907sh, 1893s, 1872s; (Nujol/cm-1): 2011s,
1916sh, 1897s, 1858s. 1H NMR (CDCl3): d 1.25 ([12H], s, MeSb),
1.87 ([3H], s, MeN), 3.61 ([4H], s, CH2N), 7.23–7.49 ([8H], m,
fac-[Mo(CO)3{S(CH2-2-C6H4SbMe2)2}]
Mo(CO)6 (0.13 g, 0.48 mmol) was dissolved in acetonitrile (50 mL)
and the solution refluxed for 16 h under a flow of argon, resulting
in a pale yellow solution. A solution of S(CH2-2-C6H4SbMe2)2
(0.25 g, 0.48 mmol) in acetonitrile (40 mL) was added and
the mixture allowed to stir for 5 h at room temperature. The
solvent was removed in vacuo, yielding a brown residue which
was dissolved in dichloromethane (20 mL), filtered and the filtrate
concentrated in vacuo to ca. 5 mL. The addition of hexane (5 mL)
precipitated a beige powder (0.15 g, 46%), which was collected
1
aromatic CH). 13C{ H} NMR (CDCl3): d 2.9 (MeSb), 42.3 (MeN),
1
2
by filtration. Required for C21H24MoO3SSb2· CH2Cl2: C, 34.4; H,
65.2 (CH2), 128.9, 130.0, 132.4, 134.5, 134.6 (Caromatic), 143.4 (Cipso),
203.3 (1JWC = 124 Hz, CO), 206.5 (1JWC = 161 Hz, CO). MS (FAB):
m/z = 808 [M]+, 793 [M - Me]+.
3.4. Found: C, 35.0; H, 3.1%. IR (CH2Cl2/cm-1): 1939s, 1841s,br;
(Nujol/cm-1): 1933s, 1928sh, 1839s, 1825s. H NMR (CDCl3): d
1
1.09 ([6H], s, MeSb) and 1.37 ([6H], s, MeSb), 3.58 ([2H], s, CH2S),
3.61 ([2H], s CH2S), 7.1–7.6 ([8H] aromatic CH). 13C{ H} NMR
1
[Cr(CO)4{MeN(CH2-2-C6H4SbMe2)2}]
(CDCl3): d -0.3 and 0.7 (MeSb), 46.2 (CH2S), 130.3, 130.4, 131.9,
132.4, 140.2, 148.0 (Caromatic), 218.7 (CO), 223.3 (CO). MS (CI):
m/z = 696 [M]+.
[Cr(CO)4(nbd)] (0.10 g, 0.39 mmol) and MeN(CH2-2-
C6H4SbMe2)2 (0.20 g, 0.39 mmol) were dissolved in hexane (40 mL)
and refluxed for 7 h, then stirred overnight. The solution was
filtered and the filtrate reduced in vacuo to ca. 7 mL, causing
precipitation of a yellow solid, which was isolated by filtration
(0.05 g, 19%). Yellow crystals were grown from the filtrate (4 ◦C).
Required for C23H27CrNO4Sb2: C, 40.8; H, 4.0; N, 2.1. Found:
C, 41.8; H, 4.2; N, 2.0%. IR (CH2Cl2/cm-1): 1999s, 1906s, 1890s,
[Mn(CO)3{S(CH2-2-C6H4SbMe2)2}][CF3SO3]
Mn(CO)5Br (0.08 g, 0.29 mmol) and Ag[CF3SO3] (0.075 g,
0.29 mmol) were dissolved in acetone (40 mL) and refluxed in
the dark for 1 h. The resulting yellow solution was allowed to cool
to room temperature, and filtered to remove the AgBr precipitate.
S(CH2-2-C6H4SbMe2)2 (0.15 g, 0.29 mmol) was added and the mix-
ture refluxed for 20 min, then stirred at room temperature for 18 h.
The volatiles were removed in vacuo, resulting in yellow/brown
oil, which was dissolved in dichloromethane (10 mL), filtered to
give a bright yellow solution, and then concentrated to ca. 5 mL.
The addition of diethyl ether (5 mL) afforded a yellow precipitate
(0.05 g, 21%), which was isolated by filtration. The filtrate was
stored at 4 ◦C (16 h), yielding yellow block shaped crystals.
Required for C22H24F3MnO6S2Sb2: C, 32.9, 3.0. Found: C, 32.3;
H, 3.1%. IR (CH2Cl2/cm-1): 2031s, 1963m, 1953m; (Nujol/cm-1):
2020s, 1943s, 1927s. 1H NMR (CDCl3): d 1.51 ([6H], s, MeSb) and
1.67 ([6H], s, MeSb), 3.72 ([4H], br m, CH2S), 7.3–7.6 ([8H], m,
CHaromatic). 13C NMR (CDCl3): d -1.94, -1.38 (MeSb), 42.8 (CH2S),
125.9, 130.8, 132.2, 132.4, 132.7 and 138.5 (Caromatic), 217 vbr (CO).
1
1870sh; (Nujol/cm-1): 1999m, 1915m, 1893s, 1859m. H NMR
(CDCl3): d 1.09 (12H, s, MeSb), 1.95 (3H, s, MeN), 3.53 (4H, s,
1
CH2N), 7.14–7.62 (8H, m, aromatic CH). 13C{ H} NMR (CDCl3):
d 1.49 (MeSb), 43.1 (MeN), 65.2 (CH2N), 128.7, 129.6, 132.1,
134.6, 136.6 (Caromatic), 143.3 (Cipso), 223.0 (CO), 229.3 (CO). MS
(FAB): m/z = 676 [M]+, 564 [M - 4CO]+.
This compounds was also identified as a major product from the
reaction of [Cr(CO)5(thf)] with the ligand, but could not readily
be separated from the pentacarbonyl [{Cr(CO)5}2{MeN(CH2-2-
C6H4SbMe2)2}] also produced.
fac-[Cr(CO)3{S(CH2-2-C6H4SbMe2)2}]
Cr(CO)6 (0.13 g, 0.58 mmol) was dissolved in acetonitrile (50 mL)
and refluxed for 20 h, resulting in a bright yellow solution and
some green solid. A solution of S(CH2-2-C6H4SbMe2)2 (0.29 g,
0.58 mmol) in acetonitrile (40 mL) and dichloromethane (5 mL)
was added, and the resulting mixture stirred for 1 h at room
temperature. The volatiles were removed in vacuo and the resulting
55Mn NMR (CDCl3): d -1418 (W1 = 3000 Hz). MS (ESI+): m/z =
2
655 [Mn(CO)3{S(CH2-2-C6H4SbMe2)2}]+, 571 [Mn{S(CH2-2-
C6H4SbMe2)2}]+.
6572 | Dalton Trans., 2011, 40, 6565–6574
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[Mn(CO)3{MeN(CH2-2-C6H4SbMe2)2}][CF3SO3]
Mn(CO)5Br (0.08 g, 0.29 mmol) and Ag[CF3SO3] (0.075 g,
0.29 mmol) were dissolved in acetone (40 mL) and refluxed in
the dark for 1 h. The resulting yellow solution was allowed
to cool to room temperature, and filtered to remove the AgBr
precipitate. MeN(CH2-2-C6H4SbMe2)2 (0.15 g, 0.29 mmol) was
added and the mixture refluxed for 20 min, then stirred for 18 h.
The volatiles were removed in vacuo, leaving a yellow/green oil,
which was redissolved in dichloromethane (10 mL), filtered to
give a bright yellow solution, and concentrated to ca. 5 mL.
The addition of hexane (10 mL) afforded a yellow precipitate
(0.18 g, 77%), which was isolated by filtration. The filtrate was
stored at 4 ◦C (16 h), yielding yellow crystals. IR (CH2Cl2/cm-1):
2023s, 1950s, 1935s; (Nujol/cm-1): 2014s, 1935sh, 1929s. 1H NMR
(CDCl3): d 1.15*, 1.52 (br, s, MeSb), 2.01*, 2.83 (s, MeN), 3.48*,
4.01–4.12 (br m, CH2N), 7.3–7.8 (m, CHaromatic) (* minor species).
1
13C{ H} NMR (CD2Cl2): d -5.4, -3.0*, -1.7*, -1.0 (MeSb), 59.0
(MeN)†, 74.9*, 76.7 (CH2), 125.8 129.9, 130.4, 130.6, 131.6, 132.5,
133.1, 134.0, 134.8, 139.9, 140.4 (Caromatic), 215.1, 216.2*, 218.0*,
219.6 (CO). 19F NMR (CDCl3) d -77.0 (s), -77.8 (vbr). 55Mn
NMR (CH2Cl2) d -1745 (W1 = 4500 Hz). MS (ESI+): m/z = 652
2
[Mn(CO)3{MeN(CH2-2-C6H4SbMe2)2}]+, 568 [Mn{MeN(CH2-2-
C6H4SbMe2)2}]+. († the second MeN- resonance is obscured by
solvent).
X-Ray crystallography
Details of the crystallographic data collection and refinement
parameters are given in Table 8. Crystals were obtained as
described above. Data collection used a Nonius Kappa CCD
diffractometer fitted with monochromated (confocal mirrors)
˚
Mo-Ka X-radiation (l = 0.71073 A). Crystals were held at
120 K in a nitrogen gas stream. Structure solution and refine-
ment were routine except as described below,23–25 with hydrogen
atoms on C added to the model in calculated positions. Both
[M(CO)4{O(CH2CH2SbMe2)2}] (M = Cr or W) showed some
disorder in the CH2CH2OCH2CH2 unit. This was modelled
satisfactorily using partial atom occupancies, giving two different
conformations in approximately 50 : 50 ratio. However, the disor-
der precludes detailed analysis of bond distances in this region.
CCDC 817769–817775 contain the supplementary crystallo-
graphic data for this paper.†
Acknowledgements
We thank EPSRC for support (EP/F038763), for a studentship
(S.L.B) and Dr M. Webster for assistance with the X-ray crystal-
lographic analyses.
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6574 | Dalton Trans., 2011, 40, 6565–6574
This journal is
The Royal Society of Chemistry 2011
©