The coordination and rearrangement of some organic chalcogenides on a rhodium-rhodium bond; The reactions with dialkylsulfanes and alkanethiols

Article abstract of DOI:10.1016/S0022-328X(97)00398-7

When solutions of [Cp₂Rh₂(μ-CO)(μ-η²:η ²-CF₃C₂CF₃)] (I) in petroleum ether or chlorinated hydrocarbons were treated with the dialkylsulfanes SRR′(R=R′=Me, Et, Pr, Bz; RR′=MeEt), the addition products [Cp₂Rh₂(CO)(SRR′)(μ-η¹:η ¹-CF₃C₂CF₃)] (III, a-e) were formed reversibly. The complexes (III) have been characterized spectroscopically in solutions containing excess ligand. Removal of excess ligand and solvent regenerated (I). When left in solution, a number of the dialkylsulfane complexes underwent interesting transformations. The complex (IIIa, R=R′=Me) converted to [Cp₂Rh₂{μ-η¹:η²-C(CF ₃)C(CF₃)H}(μ₂-SEt)] (IVa, R=Et); this involves a β-proton transfer accompanied by a Stevens rearrangement to convert {S(CH₂^-)CH₃} to (SCH₂CH₃)^-. The structure of (IVa) was determined by X-ray crystallography. Two rearrangement products were formed when (IIIb, R=R′=Et) was left in solution. One was characterized from spectroscopic data as [Cp₂Rh₂{μ-η¹:η²-C(CF ₃)C(CF₃)H}(μ₂-SCHMeEt)] (IVb), which is formed by a Stevens rearrangement after transfer of a β-proton. The other was identified as (IVa, R=Et), which is formed after proton abstraction from a γ-carbon followed by elimination of ethene. A number of μ-thiolato complexes (IVa-h, R=Me, Et, Pr, CHMeEt, Prⁱ, Bu, Bu^t and Ph) were formed directly by treatment of (I) with the appropriate alkanethiol RSH. In some instances (R=CHMeEt, Prⁱ, and Bu^t), a second product of formula [Cp₂Rh₂(μ-CO){μ-η²:η ¹-CH(CF₃)C(CF₃)SCR¹R ²R³)] (VI, a-c) was formed. The molecular structure of (VIb, R¹=H, R²=R³=Me) was determined by single crystal X-ray diffraction analysis.

Full text of DOI:10.1016/S0022-328X(97)00398-7

Ž
.
Journal of Organometallic Chemistry 551 1998 195–206
The coordination and rearrangement of some organic chalcogenides on a
rhodium–rhodium bond; the reactions with dialkylsulfanes and
1
alkanethiols
a
a
b
Michael P. Devery , Ron S. Dickson a,), Gary D. Fallon , Brian W. Skelton ,
b
Allan H. White
a
Department of Chemistry, Monash UniÕersity, Clayton, Victoria 3168, Australia
School of Chemistry, UniÕersity of Western Australia, Nedlands, Western Australia 6907, Australia
b
Received 14 May 1997
Abstract
2
2
w
Ž
.Ž
.x Ž .
When solutions of Cp2Rh2 m-CO m-h :h -CF3C2CF3 I in petroleum ether or chlorinated hydrocarbons were treated with the
XŽ
.
dialkylsulfanes SRR RsR sMe, Et, Pr, Bz; RR sMeEt , the addition products Cp2Rh2 CO SRR m-h :h -CF3C2CF3 III, a–e
.
w
Ž
.Ž
were formed reversibly. The complexes III have been characterized spectroscopically in solutions containing excess ligand. Removal of
Ž .
X.Ž
.x Ž
X
X
1
1
Ž
.
excess ligand and solvent regenerated I . When left in solution, a number of the dialkylsulfane complexes underwent interesting
X
1
2
Ž
.
w
Ä
Ž
.
. Ž
4
. 4Ž
.x Ž
.
transformations. The complex IIIa, RsR sMe converted to Cp2Rh2 m-h :h -C CF3 C CF3 H m2-SEt
IVa, RsEt ; this
y
y
Ä Ž .
Ž
.
.
Ž
involves a b-proton transfer accompanied by a Stevens rearrangement to convert S CH2 CH3 to SCH2CH3 . The structure of IVa
X
Ž
was determined by X-ray crystallography. Two rearrangement products were formed when IIIb, RsR sEt was left in solution. One
was characterized from spectroscopic data as Cp2Rh2 m-h :h -C CF3 C CF3 H m2-SCHMeEt IVb , which is formed by a Stevens
1
2
w
Ä
Ž
. Ž
Ž
. 4Ž
.x Ž
.
.
rearrangement after transfer of a b-proton. The other was identified as IVa, RsEt , which is formed after proton abstraction from a
i
t
Ž
.
g-carbon followed by elimination of ethene. A number of m-thiolato complexes IVa–h, RsMe, Et, Pr, CHMeEt, Pr , Bu, Bu and Ph
i
t
Ž .
Ž
.
were formed directly by treatment of I with the appropriate alkanethiol RSH. In some instances RsCHMeEt, Pr , and Bu , a second
2
1
1 2
w
Ž
.Ä
Ž
. Ž
.
3.x Ž
VI, a–c was formed. The molecular structure of VIb,
.
Ž
product of formula Cp2Rh2 m-CO m-h :h -CH CF3 C CF3 SCR R R
1
2
3
.
R sH, R sR sMe was determined by single crystal X-ray diffraction analysis. q 1998 Elsevier Science S.A.
Keywords: Rhodium; Chalcogenides; Dialkylsulfane; Alkanethiol; Stevens rearrangement
1. Introduction
example where initial coordination of NR leads to a
spontaneous intramolecular rearrangement reaction to
generate bridging acrylam ide ligand
Ž . Ž . Ž . Ž x w
A range of group 14 and 15 ligands add coordina-
a
w
Ž
.Ž
w
.
x
tively to the dirhodium complex Cp2 Rh2 m-CO m-
N R C O C CF3 C CF3 2,3 . Prompted by the con-
siderable continuing interest in the behaviour of
h 2 :h 2-CF3 C 2 CF3
.Ž .Ž
I
to give the products
.
x
1
Ž .
1
w
Ž
.
x
Ž
w x
Cp2 Rh2 CO L m-h :h -CF3C2CF3
II; e.g., Ls
organosulfur ligands in metal complexes 4 , we have
X
.
w x
CNR, CRR , or PR3 1 . In many instances, the added
ligand participates in further bond making and breaking
processes within the coordination sphere of the Rh–Rh
begun an investigation of reactions between group 16
Ž .
ligands and the complex I . We find that facile H-
transfer reactions occur with thiols, but more surpris-
ingly, some reactions with dialkylsulfanes can also lead
to H-transfer. In these latter reactions, an alkyl C–H
bond of the coordinated R2 S ligand is activated under
extremely mild conditions. We report the results of
these investigations in the present paper. Preliminary
results covering part of this study have been reported
Ž .
I is an
bond. The addition of nitrene sources to
)
Corresponding author.
1 Dedicated to Professor Peter Maitlis in celebration of his 65th
birthday.
0022-328Xr98r$19.00 q 1998 Elsevier Science S.A. All rights reserved.

(
)
196
M.P. DeÕery et al.rJournal of Organometallic Chemistry 551 1998 195–206
2
2
w x
w x
w
Ž
.Ž
5 . In a subsequent paper 6 , we extend the study to
some cyclic sulfanes and some organo telluranes.
use. The complex Cp2 Rh 2 m-CO m-h :h -
.
x Ž .
I was prepared as described in
Organometallic Syntheses 8 . Most sulfur ligands were
obtained from Sigma-Aldrich and used as received;
thiophenol was obtained from Merck.
CF3C2CF3
w x
2
2
[(
(
)(
2.4. Reaction of
)] ( )
Cp2 Rh2 m-CO m-h :h -
CF3C2CF3
I with SMe2
Ž
.
A large excess of dimethylsulfane 0.5 ml, 6.8 mmol
Ž . Ž
was injected into a stirred solution of I 0.084 g, 0.16
mmol in petroleum ether b.p. 30–408C 20 ml . The
.
Ž
. Ž
.
color of the solution changed instantly from green to
dark cherry red. The complex I was regenerated when
2. Experimental
Ž .
solvent and dimethylsulfane were removed under vac-
uum from this sample. A 4-fold excess of dimethylsul-
fane was added to solutions of I in chlorinated hydro-
carbons, and IR and NMR spectroscopic results were
recorded for the red solutions. This indicated the pres-
2.1. General procedures
Ž .
All reactions were carried out under an atmosphere
of purified nitrogen in oven-dried Schlenk flasks. Purifi-
cation of products was generally achieved by prepara-
tive-scale thin-layer chromatography which was carried
out on 20 by 20 cm glass plates with a 1:1 silica gel
1
1
w
Ž
.Ž .x
.Ž
.
IIIa; RsR smethyl . IR spectrum CHCl3 : n CO
ence of Cp2 Rh2 CO SMe2 m-h :h -CF3C2CF3
X
Ž
.
Ž
.
Ž
1
at 1988 s cmy1. H NMR spectrum CDCl3 : d Cp at
Ž
.
Ž
.
Ž
.
G-HF254 mixture Type 60, Merck as adsorbent. All
separations were achieved on deactivated plates, ob-
tained by drying at room temperature only. Microanaly-
ses were performed by the Campbell Microanalytical
Laboratory, University of Otago, New Zealand. Melting
points were determined on an Electrothermal IAG304
instrument using analytically pure samples and are un-
corrected.
Ž
5.42 and 5.21 the resonance for coordinated SMe2 was
obscured by that of the excess free ligand . 19 F NMR
.
3
Ž
.
Ž5
spectrum CDCl3 : 2=qd JF – F s11 Hz and JRh – F
.
s3 Hz of equal intensity at d y52.7 and y55.1. The
Ž . Ž Ž
.
Ž
.
.
.
starting compound I d Cp at 5.45, d CF3 at y52.2
Ž . Ž
was also present, with the ratio of I : IIIa s3:5. The
original reaction solution in petroleum ether was stirred
at room temperature for 4 h, with a slow stream of N2
bubbling through the solution to displace CO and inhibit
1
1
2.2. Instrumentation
w
Ž
. Ž .x
the formation of Cp2 Rh2 CO m-h :h -CF3C2CF3
2
Ž
.
II, LsCO . Monitoring of a sample by IR spec-
Ž
.
Solution infrared spectra KBr windows were ob-
tained using a Perkin Elmer 1600 Fourier transform
spectrometer. NMR spectra were measured on Bruker
AC 200, AM 300, or DRX400 spectrometers. Deuter-
Ž .
troscopy showed the total disappearance of both I and
Ž
.
IIIa . All volatiles were then removed under vacuum
from the purple solution, and the residue was dissolved
in a small volume of dichloromethane. TLC of this
Ž
.
ated solvents CDCl3 were used as internal locks.
Chemical shifts are in parts per million from internal
Ž
.
solution with dichloromethane–hexane 1:1 as eluent
separated two major products from several minor impu-
Me4Si for H and 13C, CCl3F for 19 F, and Me2Te for
1
Ž
.
rities. A yellow band Rf s0.9 was extracted with
125Te; in all cases, a positive chemical shift denotes a
resonance downfield from the reference. Multiplicities
dichloromethane and solvent evaporated to produce a
w x
yellow solid, which was identified spectroscopically 8
19
1H and F NMR as the dicarbonyl complex II,
. Ž
Ž
.
.
Ž
.
Ž
.
are reported as s singlet , d doublet , t triplet , q
quartet , and m multiplet . Electron impact mass spec-
Ž
.
Ž
Ž
.
Ž
.
LsCO 0.015 g, 17% . Extraction of the other major
tra were obtained by using a VG TRIO-1 GCMS spec-
trometer operating at 70 eV and 2008C inlet tempera-
ture.
Ž
.
band Rf s0.6 with dichloromethane and evaporation
2
o f so lv en t y ield ed
. Ž
C p 2 R h 2 m -h :h 1 -
w
Ä
Ž
.
4
Ž
Ž
.
x
Ž
.
C CF3 C CF3 H m2-SEt IVa; Rsethyl as a purple
.
crystalline solid 0.056 g, 63% , mp 1358C. Anal. Found:
2.3. Materials
C, 34.0; H, 3.3. C16 H16 F6Rh2 S. Calc.: C, 34.3; H,
Ž
.
Ž
.
2.9%. IR spectrum CHCl3 : no n CO peaks observed.
1
Ž
.
Ž
.
Acetone was analytical grade reagent; hydrocarbons
and dichloromethane were purified by distillation under
nitrogen from the appropriate drying agent 7 . All
solvents were stored in the dark over activated 4A
molecular sieves and were purged with nitrogen prior to
H NMR spectrum CDCl3 : d 5.49 s, 5H, Cp , 5.31
X
Ž
.
Ž
s, 5H, Cp , 2.64 m, 2H, CHH ; decoupling with the
CH3 resonance produced 2 doublets, 2JH – H s12.6 Hz ,
w x
.
X
3
Ž
Ž
. .
Ž
1.44 q, 1H, JH – F s10.0 Hz, C CF3 H , 1.37 t, 3H,
3
19
.
Ž
.
JH – H s7.5 Hz, CH3 . F NMR spectrum CDCl3 : d

(
)
M.P. DeÕery et al.rJournal of Organometallic Chemistry 551 1998 195–206
197
5
Ž
.
Ž
. Ž
.
y50.3 q, 3F, JF – F s12.7 Hz, CF3 and y53.8 m,
methylpropyl 0.007 g, 10% as a purple solid, mp
3F, JF – H s10.0 Hz and JF – F s12.7 Hz, CF3 . 13C
3
5
.
1408C. This complex was isolated in significantly higher
yield from the reaction of I with 2-butanethiol which
is described in Section 2.7; spectroscopic characteriza-
tion of the compound is given there. Another purple
1
Ž
.
Ž
Ž .
NMR spectrum CDCl3 : d 129.0 q, JC – F s274 Hz,
1
.
Ž
.
Ž
CF3 , 126.0 q, JC – F s 275 Hz, CF3 , 91.6 s,
1
Ž
.
.
Ž
.
Ž
C CF3 5C , 86.1 d, JC – Rh s5.3 Hz, Cp , 83.6 d,
1
2
1
.
Ž
Ž
. .
Ž
Ž
. w Ä
R f s 0.6 yielded Cp2 Rh 2 m-h :h -
JC – Rh s5.3 Hz, Cp , 64.3 q, C5C CF3 H , 43.2 s,
band
.
Ž
.
Ž
Ž
. Ž
.
4
Ž
.
x
Ž
. Ž
CH2 , 18.1 s, Me . Mass spectrum, mrz relative
C CF3 C CF3 H m2-SEt IVa, Rsethyl 0.020 g,
.
Ž
.
w
Ž
.
.
intensity, assignment : 560 20, M , 531 10, M–Et ,
31% which was described in Section 2.5. The final
Ž
w
xq xq
.
Ž
.
Ž
.
368 30, C10 H10RhS , 303 15, C5H5Rh2 S , 233
100, C10 H10Rh .
band Rf s0.2 was blue; it was present in trace quanti-
Ž
w
xq
.
ties and was not further characterized.
5
2
1
[(
)
{
[(
{
)
2.5. AlternatiÕe preparation of h -C5 H5 2 Rh2 m-
2.7. AlternatiÕe preparation of Cp2 Rh2 m-h :h -
2
1
1
1
(
) (
)
}
(
)] (
)
(
) (
)
}{
}
] (
h :h -C CF3 C CF3 H m2-SEt IVa from EtSH
C CF3 C CF3 H m-h :h -SCHMeEt
IVb from 2-
butanethiol
Ž
.
An excess of ethanethiol 0.2 ml, 2.7 mmol was
added dropwise from a syringe to a stirred solution of
I
Ž . Ž
.
Ž
To a stirred solution of I 0.045 g, 0.086 mmol in
dichloromethane 15 ml was added 2-butanethiol 0.5
ml, 4.6 mmol . There was an instant color change from
green to crimson. After stirring the reaction mixture at
room temperature for 4 h, all volatiles were removed
under vacuum. The residue was dissolved in
dichloromethane, and TLC of the solution with a mix-
ture of hexane–dichloromethane 1:1 as eluent sepa-
rated three bands. The first, a yellow band, was present
in trace amounts only. It was identified from its color
Ž . Ž
. Ž .
Ž
.
0.010 g, 0.019 mmol in petroleum ether 15 ml .
.
There was an instant color change from green to deep
crimson. Stirring was continued for 4 h, and all volatiles
were then removed under vacuum. TLC of a solution of
the residue dissolved in dichloromethane with
Ž
.
dichloromethane–hexane 1:1 as eluent separated two
major bands from minor impurities. A yellow band
Ž
.
Ž
.
Rf s0.9 was extracted with dichloromethane; evapo-
ration of solvent from the extract gave the dicarbonyl
Ž
. Ž
.
Ž
.
Ž
.
complex II, LsCO 0.001 g, 10% which was char-
and Rf value 0.9 as II, LsCO . A major purple
Ž
.
acterized spectroscopically. Extraction of a dark purple
band Rf s0.8 was extracted with dichloromethane,
Ž
.
band Rf s0.6 with dichloromethane and removal of
and evaporation of solvent left a purple solid which was
m - h 2 :h -
1
2
1
w
2 Ä
C p R h
2
w
Ä
Ž
. Ž
. 4Ä
s o lv e n t y ie ld e d
identified as Cp2 Rh2 m-h :h -C CF3 C CF3 H m2-
Ž
. Ž
.
4
Ž
.
x
Ž
. Ž
4
x
Ž
. Ž
.
C CF3 C CF3 H m2-SEt IVa, Rsethyl 0.007 g,
SCHMeEt IVb, Rs1-methylpropyl 0.022 g, 43% ,
.
65% as a purple solid.
mp 1408C. Anal. Found: C, 37.7; H, 4.3.
C18 H20 F6Rh2 S. Calc.: C, 36.8; H, 3.4%. IR spectrum
1
2
2
[(
(
)(
Ž
.
Ž
.
2.6. Reaction of
)] ( )
Cp2 Rh2 m-CO m-h :h -
CHCl3 , no n CO peaks observed. H NMR spectrum
Ž
.
Ž
CF3C2CF3
1 with diethylsulfane
CDCl3 : d 5.50 and 5.48 2=d of approximately
2
equal intensity, 5H, JH – Rh s0.5 Hz, Cp of stereoiso-
2
.
Ž
.
The general procedure described in Section 2.4 for
the reaction with SMe2 was followed. The initial prod-
mers , 5.33 and 5.31 2=d, 5H, JH – Rh s0.5 Hz, Cp ,
Ž
.
Ž
.
Ž
2.50 m, 1H, CH , 1.9–1.6 br m, 2H, CH2 , 1.49 q,
3
Ž
. .
Ž
u c t in
s o lu tio n
Cp2 Rh2 CO SEt2 m-h :h -CF3C2CF3
w a s id e n tifie d
a s
1H, JH – F s10.0 Hz, C CF3 H , 1.35 and 1.32 2=d,
3
3
1
1
w
Ž
.Ž
.Ž
.
x
Ž
.
Ž
IIIb, Rs
3H, JH – H s6.7 Hz, S-CH-CH3 , 1.00 td, 3H, JH – H
X
s7.5 Hz and 4JH – H s1.5 Hz, CH3 of ethyl . 19 F NMR
.
Ž
Ž
.
Ž
.
.
R sethyl . IR spectrum CHCl3 , n CO at 1990 s
1
cmy1. H NMR spectrum CDCl3 : d 5.44 s, 5H, Cp ,
.
Ž
.
Ž
.
Ž
spectrum CDCl3 : d y49.9 2=q of equal intensity
5
Ž
. Ž
.
5.22 s, 5H, Cp the resonances for coordinated SEt2
were obscured by those for the large excess of free
separated by 0.02 Hz, 3F, JF – F s13.0 Hz, CF3 and
13
Ž
.
Ä1
4
y53.9 m, 3F, CF3H .
C H NMR spectrum
ligand . 19 F NMR spectrum CDCl3 : two quartets
.
Ž
.
Ž
Ž
Ž
Ž
.
Ž
.
.
CDCl3 : d 86.1 and 86.0 2=s, Cp , 83.7 and 83.6
2=s, Cp , 55.7 and 55.6 2=s, CH , 33.4 and 32.3
2=s, CH2 , 23.2 and 22.1 2=s, S-CH-CH3 , 11.4
s, CH3 of ethyl -resonances for the alkenyl carbons
Ž
.
.
Ž
JF – F s11.4 Hz of equal intensity at d y52.4 and
Ž .
.
Ž
.
y55.1. The starting compound I was also present;
.
even with a 60-fold excess of the ligand, the ratio of
Ž . Ž
.
I : IIIb was determined to be 5:2. A solution contain-
ing complex I 0.061 g, 0.16 mmol and SEt2 0.50
ml, 4.6 mmol in petroleum ether 30 ml was left for
18 h. TLC workup with hexane–dichloromethane 1:1
as eluent separated four bands that were each extracted
could not be assigned with confidence. Mass spectrum,
Ž . Ž
.
.
Ž
Ž
.
Ž
.
mrz relative intensity, assignment : 588 6, M , 531
xq
8, M–C4 H9 , 368 15, C10 H10RhS , 303 12,
.
Ž
Ž
.
Ž
.
Ž
w
xq xq
Ž
w
w
.
Ž
Ž
.
w
C5H5Rh2 S , 233 100, C10 H10Rh , 168 18,
w
xq
.
Ž
xq
.
C5H5Rh , 57 18, C4 H9 .
Ž
.
Ž
with dichloromethane. The first yellow band Rf s0.9
Extraction of the remaining significant band Rf s
Ž
. Ž
.
.
gave II, LsCO 0.025 g, 37% . The second band
0.3 gave a dichroic green-brown solid which was iden-
1
m -h 2 :h -
. Ä
m -C O
Ž
.
w
Ä
w
Ž
Ž
Rf s0.8 was purple and this yielded Cp2 Rh2 m-
tifie d
a s
Ž
C p 2 R h
x2
.
2
1
Ž
. Ž 4x Ž
.
4Ä
Ž
.
.
4
h :h -C CF3 C CF3 H m2-SCHMeEt IVb, Rs1-
C CF3 HC CF3 SCHMeEt VIa, Rs1-methylpropyl

(
)
198
M.P. DeÕery et al.rJournal of Organometallic Chemistry 551 1998 195–206
Ž
.
Ž
.
0.012 g, 23% . Anal. Found: C, 37.2; H, 3.2.
tion of the complex VII will be described in a subse-
w x
C19 H20 F6ORh2 S. Calc.: C, 37.0; H, 3.3%. IR spectrum
quent paper 6 .
CHCl3 , n CO at 1801 cm
.
1H NMR spectrum
y1
Ž
Ž
Ž
Ž
.
.
Ž
.
2.8.2. SPr2n
Ž
.
Ž
.
CDCl3 : d 5.49 s, 5H, Cp , 5.37 s, 5H, Cp , 2.0–1.2
br m, 4H, CH2 , CH and C CF3 H , 1.15 and 0.98
2=d of equal intensity, 3H, JH – H s6.7 and 6.9 Hz,
Ž
. .
The procedure described in Section 2.4 was used. A
very large excess 250-fold of this ligand was required
to effect a colour change from green to red. The addi-
3
Ž
.
.
Ž
SCHCH3 of stereoisomers , 0.90 and 0.89 2=t of
equal intensity, 3H, JH – H s7.4 Hz, CH3 of ethyl . 19 F
3
1
1
w
Ž
.Ž
n.Ž
.
x
.
tion product Cp2 Rh2 CO SPr2 m-h :h -CF3C2CF3
Ž
.
Ž
Ž
Ž
Ž
.
NMR spectrum CDCl3 : d y52.3 and y52.5 2=m
IIId was characterized spectroscopically. IR spectrum
1
CH2Cl2 : n CO at 1988 s cmy1. H NMR spectrum
.
.
Ž
.
of equal intensity, 3F, CF3H of stereoisomers, and
Ž
.
.
Ž
.
Ž
.
Ž
. Ž
y57.7 m, 3F, CF3 . Mass spectrum, mrz relative
CDCl3 : d 5.24 s, 5H, Cp , 5.02 s, 5H, Cp the
resonances for coordinated SPr2n were obscured by those
Ž
.
w
Ž
.
intensity, assignment : 616 5, M , 588 25, M–CO ,
19
Ž
w
.
Ž
xq
.
.
Ž
.
531 35, M-CO-C4 H9 , 368 10, C10 H10RhS , 303
Ž
for the free ligand. . F NMR spectrum CDCl3 : two
xq
.
Ž
w
xq
.
12, C5H5Rh2 S , 233 100, C10 H10Rh .
Ž
.
quartets JF – F s11.7 Hz of equal intensity at d y52.3
Ž .
and y55.0. The starting material I was present, with a
5
2
2
[(
)
(
)(
Ž . Ž
.
Ž
.
2.8. Reactions of h -C5 H5 2 Rh2 m-CO m-h :h -
CF3C2CF3
1:4 ratio of I : IIId . Attempts to isolate IIId resulted
)] ( )
Ž .
I with other dialkylsulfanes
in the reformation of I .
2.8.1. SEtMe
2.8.3. SBz2
Ž
.
When excess ethylmethylsulfane 0.42 g, 5.5 mmol
Again, a very large excess of the ligand was required
to effect a colour change from green to red. The addi-
tion product Cp2 Rh2 CO SBz2 m-h :h -CF3C2CF3
Ž . Ž
was added with stirring to a solution of I 0.032 g,
1
1
.
Ž
.
w
Ž
.Ž
.Ž
.
x
0.061 mmol in chloroform 20 ml , an instant colour
change from green to red occurred, indicating the pres-
Ž
Ž
Ž
.
IIIe was identified spectroscopically. IR spectrum
1
1
1
CH2Cl2 : n CO at 1976 s cmy1. H NMR spectrum
. Ž
w
Ž
.Ž .x
.Ž
.
Ž
.
ence of Cp2 Rh2 CO SEtMe m-h :h -CF3C2CF3
IIIc, RR sMeEt . IR spectrum CHCl3 : n CO at
X
Ž
.
Ž
.
Ž
.
.
Ž
.
Ž
CDCl3 : d 5.67 s, 5H, Cp , 5.28 s, 5H, Cp the
1990 s cmy1. The reaction was repeated in an NMR
resonances for coordinated Bz2 S were obscured by
1
19
.
Ž
.
tube with an 80-fold excess of ligand. H NMR spec-
those for the free ligand . F NMR spectrum CDCl3 :
Ž
.
Ž
.
Ž
. Ž
Ž
.
trum CDCl3 : d 5.42 s, 5H, Cp , 5.21 s, 5H, Cp the
two quartets JF – F s11 Hz of equal intensity at d
Ž .
Ž
.
resonances for coordinated SEtMe were obscured by
y52.0 and y55.1. The starting material I and IIIe
those for the large excess of free ligand . 19 F NMR
.
were present in a ratio of 3:1.
Ž
.
Ž
.
spectrum CDCl3 : two quartets JF – F s11.6 Hz of
2.8.4. SPr2i
equal intensity at d y52.5 and y55.1. The starting
Ž .
Ž . Ž
)
material I was still present; the ratio of I : IIIc was
1:2. The addition of further portions of SEtMe did not
change this ratio significantly. If these solutions were
No addition product was evident in solution at room
temperature. When a mixture of
dichloromethane was refluxed or exposed to sunlight, a
red solution formed. Chromatographic workup yielded
and SPr2i in
Ž .
I
Ž .
evaporated to dryness at any stage, I was recovered
quantitatively. A solution containing I and a large
excess of ethylmethylsulfane in CDCl3 was left stirring
for 6 h. Monitoring by NMR spectroscopy indicated
Ž .
Ž
. Ž
.
the dicarbonyl complex II, LsCO 20% yield and
Ž
. Ž
.
the bridging sulfido complex VII 5% yield .
2
1
2
2
w
Ä
[
(
)(
that traces of the complex Cp2 Rh2 m-h :h -
2.9. Reactions of
)] ( )
Cp2 Rh2 m-CO m-h :h -
Ž
. Ž
.
4
Ž
.
x
Ž
.
IVc had formed. This
C CF3 C CF3 H m2-SMe
complex was identified spectroscopically by comparison
Ž .
CF3C2CF3
I with other thiols
with an authentic sample prepared by reaction of I
The general procedure described above in Section 2.5
for the reaction with ethanethiol was followed.
with methanethiol, described separately in Section 2.9.1.
Numerous attempts were made to induce a rearrange-
ment of the coordinated sulfane. In separate experi-
2.9.1. MeSh
Ž
.
ments, solutions of the addition product IIc were
Methanethiol was generated by stirring dimethylsul-
fane with conc. sulfuric acid. The evolved gas was
bubbled through a solution of I 0.026 g, 0.049 mmol
in dichloromethane 20 ml until the color of the solu-
tion was deep crimson. The reaction solution was stirred
for a further 3 h. All volatiles were removed under
vacuum, and the residue was redissolved in
dichloromethane. Workup by TLC separated three ma-
jor bands from several minor impurities. Extraction of a
Ž
.
stirred for prolonged periods up to 5 weeks at room
temperature, refluxed, irradiated with a UV source, and
exposed to sunlight. There was extensive decomposition
upon UV irradiation, but in the other cases IIc was
recovered as the major species. On all occasions, nu-
merous trace bands were evident on TLC workup; these
Ž . Ž
.
Ž
.
Ž
.
2
1
Ž
.
w
Ä
usually included IVc and Cp2 Rh2 m-h :h -
Ž
. Ž
.
4
Ž
.
x
Ž
.
C CF3 C CF3 CO m2-S VII , but there was no evi-
Ž
.
dence of any other rearranged products. Characteriza-
yellow band Rf s0.9 with dichloromethane and re-

(
)
M.P. DeÕery et al.rJournal of Organometallic Chemistry 551 1998 195–206
199
2
1
Ž
w
Ž
.
Ä
Ž
.
Ž
.
i4
x
Ž
.
moval of solvent yielded the dicarbonyl complex II,
Cp2 Rh2 m-CO m-h :h -C CF3 HC CF3 SPr
VIb
. Ž
.
Ž
Ž
.
LsCO 0.005 g, 18% . A major purple product Rf s
35% yield . Anal. Found: C, 35.7; H, 2.9.
C18 H18 F6ORh2 S. Calc.: C, 35.9; H, 3.0%. IR spectrum
CHCl3 : n CO at 1801 cm
.
0.8 was extracted with dichloromethane and isolated by
.
1H NMR spectrum
y1
Ž
Ž
Ž
.
.
Ž
.
evaporation of solvent as a purple solid. It was charac-
terized spectroscopically as Cp2 Rh2 m-h :h -
2
1
w
Ä
Ž
.
Ž
.
CDCl3 : d 5.49 s, 5H, Cp , 5.38 s, 5H, Cp , 2.04
3
3
Ž
. Ž . Ž
.
4
Ž
.
x
Ž
.
.
Ž
C CF3 C CF3 H m2-SMe IVc 0.010 g, 37% . IR
septet, 1H, JH – H s6.7 Hz, CH , 1.89 q, 1H, JH – F
s
spectrum CH2Cl2 : no n CO peaks observed. 1H
3
Ž
.
Ž
.
Ž
. .
Ž
.
10.0 Hz, C CF3 H , 1.20 d, 3H, JH – H s6.6 Hz, CH3 ,
1.02 d, 3H, JH – H s6.8 Hz, CH3 . 19 F NMR spectrum
3
Ž
.
Ž
.
Ž
Ž
.
NMR spectrum CDCl3 : d 5.48 s, 5H, Cp , 5.31 s,
3
3
.
Ž
X
Ž
.
Ž
Ž
. .
Ž
5H, Cp , 2.41 dd, 3H, JH – Rh s JH – Rh s1.5 Hz,
CDCl3 : d y52.3 m, 3F, C CF3 H , and y57.8 q,
19
5
.
Ž
Ž
.
Ž
.
.
Ž
SCH3 . F NMR spectrum CDCl3 : dy50.4 q, 3F,
3F, JF – F s10.9 Hz, CF3 . Mass spectrum, mrz rela-
.
.
Ž
.
Ž
.
.
JF – F s13 Hz, CF3 , y54.0 m, 3F, CF3 . Mass spec-
tive intensity, assignment 602 1, M , 574 9, M–CO ,
i
xq
Ž
Ž
.
Ž
.
Ž
.
Ž
w
trum, mrz relative intensity, assignment 546 20, M ,
531 10, M–Pr , 368 5, C10 H10Rh2 S , 303 10,
xq xq
.
C5H5Rh2 S , 233 100, C10 H10Rh .
.
Ž
w
Ž
.
Ž
w
xq
.
Ž
w
531 5, M–Me , 368 5, C10 H10RhS , 233 100,
w
xq
.
C10 H10Rh . Only one other major product was pre-
sent green, Rf s0.3 , but it decomposed before it
Ž
.
2.9.4. BuSH
The same procedures were used. A purple crystalline
solid 54% was identified as Cp2 Rh2 m-h :h -
C CF3 C CF3 H m2-SBu
Found: C, 36.7; H, 3.2; F, 18.9. C18 H21F6Rh2 S. Calc.
C, 36.8; H, 3.4; F, 19.4%. IR spectrum CHCl3 : no
could be characterized.
2
1
Ž
.
w
Ä
2.9.2. PrSH
Ž
. Ž
.
4Ä
.
4
x
Ž
.
IVf , mp 1428C. Anal.
Ž
.
A purple crystalline solid Rf s0.7 was isolated
2
1
Ž
.
w
Ä
yield 57% and identified as Cp2 Rh2 m-h :h -
. Ž
Ž
.
Ž
.
4Ä
4
x
Ž
.
IVd , mp 1418C. Anal.
C CF3 C CF3 H m2-SPr
Found: C, 35.8; H, 3.2; F, 19.6. C17 H18 F6Rh2 S. Calc.:
1
Ž
.
Ž
.
n CO peaks observed. H NMR spectrum CDCl3 : d
5.47 s, 5H, Cp , 5.30 s, 5H, Cp , 2.60 m, 2H,
Ž
.
Ž
.
Ž
Ž
.
C, 35.6; H, 3.2; F, 19.9%. IR spectrum CHCl3 : no
3
.
Ž
.
Ž
.
S–CH2 , 1.66 m, 2H, CH2 , 1.46 q, 1H, JH – F s10.0
1
Ž
.
Ž
.
n CO peaks observed. H NMR spectrum CDCl3 : d
3
Ž
. .
Ž
Ž
Hz, C CF3 H , 1.45 m, 2H, CH2 , 0.95 t, 3H, JH – H
3
Ž
.
Ž
.
Ž
5.47 s, 5H, Cp , 5.31 s, 5H, Cp , 2.58 t, 2H, JH – H
7.0 Hz, S–CH2 , 1.71 m, 2H, CH2 , 1.45 q, 1H,
s
19
.
Ž
.
s7.3 Hz, CH3 . F NMR spectrum CDCl3 : d y50.2
.
Ž
.
Ž
5
Ž
.
Ž
q, 3F, JF – F s12.8 Hz, CF3 and y53.8 m, 3F,
3
3
Ž
. .
Ž
JH – F s10.0 Hz, C CF3 H , 1.04 t, 3H, JH – H s7.4
JF – H s10.0 Hz and 5JF – F s12.8 Hz, CF3 . Mass spec-
3
.
19
.
Ž
.
Ž
Hz, CH3 . F NMR spectrum CDCl3 : d y50.3 q,
Ž
.
Ž
.
trum, mrz relative intensity, assignment 588 25, M ,
5
3
.
Ž
3F, JF – F s12.7 Hz, CF3 and y53.8 m, 3F, JF – H
s
Ž
.
Ž
w
xq
531 18, M–Bu , 368 25, C10 H10RhS , 303 6,
.
Ž
5
.
10.0 Hz and JF – F s12.7 Hz, CF3 . Mass spectrum,
w
xq xq
.
.
.
Ž
w
C5H5Rh2 S , 233 100, C10 H10Rh
Ž
.
Ž
,
.
Ž
mrz relative intensity, assignment 574 7, M , 531 5,
.
Ž
w
xq
.
Ž
303 10,
M –Pr , 368 25, C 10 H 10 RhS
xq xq
.
.
2.9.5. ButSH
w
.
Ž
w
C5H5Rh2 S , 233 100, C10 H10Rh
A minor yellow band which also developed during
the TLC workup was identified IR spectrum as the
Two major products were separated by TLC, with a
3:1 mixture of petroleum spirit and dichloromethane as
eluent. Extraction of one product Rf s0.7 gave a
Ž
.
Ž
.
Ž
.
dicarbonyl complex II, LsCO .
2.9.3. PriSH
The same reaction procedure was used. TLC workup
with a 3:1 mixture of petroleum spirit and dichlomethane
Ž
.
as eluent separated two major products. One Rf s0.7
Ž
.
was isolated as a purple crystalline solid 54% . It was
2
1
w
Ä
Ž
. Ž
. 4Ä
identified as Cp2 Rh2 m-h :h -C CF3 C CF3 H m2-
i4
x
Ž
.
IVe , mp 1438C. Anal. Found: C, 36.1; H, 3.0.
SPr
C17 H18 F6Rh2 S. Calc.: C, 35.6; H, 3.2%. IR spectrum
1
Ž
Ž
Ž
.
.
Ž
.
CHCl3 : no n CO peaks observed. H NMR spectrum
CDCl3 : d 5.49 s, 5H, Cp , 5.33 s, 5H, Cp , 2.72
Ž
.
Ž
.
3
3
.
Ž
septet, 1H, JH – H s6.8 Hz, CH , 1.46 q, 1H, JH – F
s
3
Ž
. .
Ž
.
10.0 Hz, C CF3 H , 1.38 t, 6H, JH – H s6.8 Hz, CH3 .
19
5
Ž
.
Ž
F NMR spectrum CDCl3 : d y49.9 q, 3F, JF – F
s
3
.
Ž
13.0 Hz, CF3 and y53.8 m, 3F, JF – H s10.0 Hz and
5
.
Ž
JF – F s13.0 Hz, CF3 . Mass spectrum, mrz relative
i
.
Ž
.
w
Ž
.
intensity, assignment 574 10, M , 531 15, M–Pr ,
Ž
w
xq xq
.
Ž
.
368 5, C10 H10RhS , 303 8, C5H5Rh2 S , 233
Ž
w
xq
.
.
100, C10 H10Rh
The other product Rf s0.3 was obtained as a
dichroic green-brown solid which was identified as
Fig. 1. Molecular projection showing the atom arrangement for IVa;
the non-hydrogen atoms are shown as 20% thermal ellipsoids; hydro-
gen atoms as spheres of arbitrary radius.
Ž
.

(
)
200
M.P. DeÕery et al.rJournal of Organometallic Chemistry 551 1998 195–206
Table 1
Ž
.
purple crystalline solid 50% which was identified as
5
2
1
Ž
.
w
Ž
.
Ä
Ž
. Ž x
.
4Ä
t4
Summary of crystal structure data for the complexes IVa and
h -C5H5 2 Rh2 m-h :h -C CF3 C CF3 H m2-SBu
IVg , mp 1608C. Anal. Found: C, 36.9; H, 3.6.
C18 H20 F6Rh2 S. Calc.: C, 36.8; H, 3.4%. IR spectrum
a
Ž
.
VIb
Ž
.
Ž
.
Ž
.
IVa
VIb
1
C16 H16 F6SRh2
560.2
Orthorhombic
C18 H18 F6ORh2 S
602.2
Orthorhombic
Ž
.
Ž
.
CHCl3 : no n CO peaks observed. H NMR spectrum
Mr
Ž
.
Ž
.
Ž
.
Ž
CDCl3 : d 5.52 s, 5H, Cp , 5.37 s, 5H, Cp , 1.59 q,
Crystal system
Space group
1H, JH – F s9.5 Hz, C CF3 H , 1.37 s, 9H, CH3 . 19 F
3
Ž
. .
Ž
.
Ž
.
Ž
.
Pbca No. 61
P 212121 No. 19
5
Ž
Ž
NMR spectrum CDCl3: d y50.3 q, 3F, JF – F s12.9
˚
Ž .
a A
Ž .
Ž .
Ž .
Ž .
16.061 2
16.679 5
3
.
Ž
Hz, CF3 and y53.4 m, 3F, JF – H s9.5 Hz and
˚
Ž .
b A
18.165 2
Ž .
15.609 3
Ž .
7.484 5
5
.
Ž
t
JF – F s12.9 Hz, CF3 . Mass spectrum, mrz relative
˚
Ž .
c A
12.344 3
.
Ž
.
Ž
.
intensity, assignment 588 6, M , 531 5, M–Bu , 368
3
˚
Ž
.
V A
3601
2.07
2176
20.0
1948
2.05
1176
18.6
Ž
w
w
xq
.
Ž
w
xq
.
Ž
Dc g cmy3
40, C10 H10RhS , 303 10, C5H5Rh2 S , 233 100,
xq
.
C10 H10Rh .
Ž
.
F 000
mMo cmy1
Ž
.
The second product Rf s0.3 was isolated as a
Specimen mm
0.40=0.12=0.12
0.17=0.08=0.60
dichroic green-brown solid which was identified as
Ž
.
Ž
.
dark red, acicular
green-brown
2
1
w
Ž
.
Ä
Ž
.
Ž
.
t4
x
Cp2 Rh 2 m-CO m-h :h -C CF3 HC CF3 SBu
Tmin, max
N
N0
R
R0
Z
Programs
0.76, 0.86
5248
2082
0.048
0.048
8
0.78, 0.89
3211
2194
0.059
0.058
4
Ž
.
VIc . Anal. Found: C, 37.5; H, 3.9. C19 H20 F6ORh2 S.
Ž
.
Ž
.
Calc.: C, 37.0; H, 3.3%. IR spectrum CHCl3 : n CO
1
at 1802 cmy1. H NMR spectrum CDCl33 : d 5.48 s,
Ž
.
Ž
.
Ž
.
Ž
5H, Cp , 5.40 s, 5H, Cp , 2.07 q, 1H, JH – F s10.1
Ž
Ž
. . . .
Ž
Ž
Hz, C CF3 H , 1.12 s, 9H, C CH3
.
19 F NMR spec-
. .
3
w
x
w x
Texsan 19
XTAL92 20
.
Ž
Ž
trum CDCl3 : d y51.9 m, 3F, C CF3 H , and y56.6
5
aAbnormal featuresrvariations in procedure: IVa : a v-scan data
collection mode was employed; reflection weights were vy1 ss 2
Ž
Ž
.
.
q, 3F, JF – F s11.0 Hz, CF3 . Mass spectrum, mrz
Ž
.
Ž
.
Ž
relative intensity, assignment 616 2, M , 588 1,
t
t
Ž
.
Ž
.
Ž
.
F ; ‘numerical’ absorption correction face indexed ; VIb : a
.
Ž
.
Ž
w
.
M–CO , 559 6, M–Bu , 531 12, M-CO-Bu , 368
Gaussian absorption correction was applied; residuals quoted apply to
both chiralities.
Ž
w
xq xq
.
Ž
.
15, C10 H10Rh2 S , 233 100, C10 H10Rh .
2.9.6. PhSH
The reaction and workup were similar to that de-
scribed above. A purple crystalline solid 64% was
Ž
.
Ž
7.60 m, 2H, o-H of C6 H5 , 7.21 m, 3H, m- and p-H
Ž
.
. Ž . Ž . Ž
of C6 H5 , 5.41 s, 5H, Cp , 5.20 s, 5H, Cp , 1.44 q,
3
isolated by TLC Rf s 0.8 and identified as
1H, JH – F s10.0 Hz, C CF3 H . 19 F NMR spectrum
Ž
.
Ž
. .
5
2
1
w
Ä
Ž
. Ž
.
4Ä
4
x
Ž
.
Ž
.
Ž
Ž
.
Cp2 Rh2 m-h :h -C CF3 C CF3 H m2-SPh IVh ,
mp 1578C. Anal. Found: C, 39.8; H, 2.6. C18 H21F6Rh2 S.
Calc.: C, 39.5; H, 2.7%. IR spectrum CHCl3 : no
n CO peaks observed. H NMR spectrum CDCl3 : d
CDCl3 : d y50.2 q, 3F, JF – F s12.7 Hz, CF3 and
3
5
y53.7 m, 3F, JF – H s10.0 Hz and JF – F s12.7 Hz,
Ž
Ž
.
. Ž
CF3 . Mass spectrum, mrz relative intensity, assign-
1
Ž
.
Ž
.
.
Ž
.
Ž
w
xq
.
Ž
ment : 608 15, M , 444 6, C10 H10RhSPh , 368 15,
w
xq
.
Ž
w
xq
.
Ž
C10 H10RhS , 277 45, C5H5RhSPh , 233 100,
w
xq
C10 H10Rh
.
.
2.9.7. Spectroscopic monitoring of the early stages of
the reaction with PhSH
In an NMR tube, 1 drop of benzenethiol was added
1
to a solution of I in CDCl3. Within 5 min, H and 19 F
Ž .
NMR spectra were recorded. One major product was
evident, making up 70% of all trifluoromethyl reso-
nances. It could not be identified from the spectroscopic
1
Ž
.
Ž
results. H NMR spectrum CDCl3 : d 5.82 q, 1H,
3
Ž
. .
Ž
JH – F s10.1 Hz, C CF3 H , 5.4–5.0 br s, 10H, 2=
19
.
Ž
.
Ž
Cp . F NMR spectrum CDCl3 : d y49.8 q, 3F,
5
.
Ž
.
JF – F s12.4 Hz, CF3 and y57.5 m, 3F, CF3 . An IR
y1
Ž
.
spectrum of the solution showed n CO at 1989 cm
.
After 20 min, the resonances for this intermediate had
totally disappeared, and the spectra indicated that the
Ž
major species present were the dicarbonyl complex II,
.
Ž
.
LsCO and the m-thiolato complex IVh in approxi-
mately equal amounts. After 18 h, a new product was
evident; this is described in Section 2.9.8.
Fig. 2. Molecular projection showing the atom arrangement in VIb;
the non-hydrogen atoms are shown as 20% thermal ellipsoids; hydro-
gen atoms as spheres of arbitrary radius.

(
)
M.P. DeÕery et al.rJournal of Organometallic Chemistry 551 1998 195–206
201
(
)
Table 3
Selected bond lengths and angles for complex VIb
2.9.8. Reaction of IVh with thiophenol
Ž
.
Ž
.
An excess of thiophenol 0.5 ml, 4.9 mmol was
added to a solution of IVh 0.028 g, 0.046 mmol in
Ž
.
. Ž
.
˚
˚
Ž .
d A
Ž .
d A
Atoms
Atoms
Ž
dichloromethane 10 ml and the solution was stirred for
several hours. During this time, the color of the solution
changed from purple to orange. All volatiles were re-
moved from the reaction mixture under vacuum. The
residue was dissolved in dichloromethane. TLC of the
solution with a 1:1 mixture of dichloromethane and
hexane as eluent separated one major band from several
minor species. The major orange band Rf s0.5 was
extracted with dichloromethane, and evaporation of sol-
vent left an orange solid, which was identified spectro-
Ž .
Rh 1 –Rh 2
a Bond lengths
Ž . Ž .
Ž .
2.662 2
1.94 1
Ž . Ž
C 01 –C 03
.
.
Ž .
1.53 2
C 01 –C 02
Ž .
Ž .
Ž
.
Ž
Ž .
1.49 2
Rh 1 –C
Ž .
Ž .
Ž .
C 1 –C 2
Ž
.
Ž .
1.49 2
Rh 1 –S
2.272 4
C 1 –C 11
Ž . Ž .
Ž .
Ž
.
.
.
.
.
Ž .
Ž .
1.45 2
Rh 1 –C 101
2.23 2
Ž .
Ž
Ž .
Ž
.
Ž
.
.
.
Ž .
1.32 2
Rh 1 –C 102
2.29 2
C 11 –F 11
Ž .
Ž
Ž .
Ž
.
Ž
Ž .
1.33 2
Rh 1 –C 103
2.21 1
C 11 –F 12
Ž .
Ž
Ž .
Ž
.
Ž
Ž .
1.35 2
Rh 1 –C 104
2.22 2
C 11 –F 13
Ž .
Ž
Ž .
Ž .
Ž
.
Ž .
1.52 2
Ž
.
Rh 1 –C 105
2.22 2
C 2 –C 21
Ž .
Ž .
Ž
.
Ž
.
.
.
Ž .
1.34 2
Rh 2 –C
2.10 1
C 21 –F 21
Ž . Ž .
Ž .
Ž
.
Ž
Ž .
1.31 2
Rh 2 –C 1
2.07 1
C 21 –F 22
Ž . Ž .
Ž .
Ž
.
Ž
Ž .
1.32 2
Rh 2 –C 2
2.07 1
C 21 –F 23
2
1
w
Ž
.Ž
.Ä
scopically as Cp2 Rh2 m-SPh HSPh m-h :h -
Ž .
Ž
.
.
.
.
.
Ž .
Ž
.
Ž
.
.
.
.
.
.
.
.
.
.
Ž .
1.39 3
Rh 2 –C 201
2.22 2
C 101 –C 102
Ž
. Ž
.
4
x
Ž
. Ž
.
C CF3 C CF3 H VIII 0.015 g, 45% . IR spectrum
Ž .
Ž
Ž .
Ž
.
Ž
Ž .
1.43 3
Rh 2 –C 202
2.20 2
C 101 –C 105
1
Ž .
Ž
Ž .
Ž
.
Ž
Ž .
1.37 3
Ž
Ž
.
Ž
.
Rh 2 –C 203
2.25 2
C 102 –C 103
CHCl3 : no n CO peaks observed. H NMR spectrum
Ž .
Ž
Ž .
Ž . Ž
Ž .
1.41 3
Rh 2 –C 204
2.28 2
C 103 –C 104
.
Ž
.
Ž
CDCl3 : d 8.1–7.0 br m, 10H, Ph , 5.06 br s, 5H,
Cp , 4.92 br s, 5H, Cp , 3.73 m, 1H, SH , 2.25 m,
Ž .
Ž
Ž .
Ž
.
Ž
Ž .
1.37 3
Rh 2 –C 205
C–O
2.22 2
C 104 –C 105
.
Ž
.
Ž
.
.
Ž
Ž .
Ž
.
Ž
Ž .
1.43 3
1.16 2
C 201 –C 202
19
Ž
. .
Ž
1H, C CF3 H . F NMR spectrum CDCl3 : d y54.4
Ž
Ž .
.
Ž .
Ž
.
Ž
Ž .
1.39 3
S–C 01
S–C 1
1.83 1
C 202 –C 203
Ž
.
Ž
Ž
. .
.
br m, 3F, CF3 and y55.8 br m, 3F, C CF3 H . Mass
Ž .
Ž . Ž
Ž .
1.35 2
1.80 1
C 202 –C 203
Ž
.
.
Ž
Ž
Ž .
1.35 2
Ž
Ž
C 203 –C 204
spectrum, mrz relative intensity, assignment : 718 1,
Ž
Ž .
1.39 3
C 204 –C 205
Ž .
b
Bond angles
Ž . Ž .
Ž .
51.4 4
Ž .
Ž
.
Ž .
114.2 5
Rh 2 –Rh 1 –C
Ž . Ž .
Rh 2 –Rh 1 –S
Rh 1 –S–C 01
Table 2
Ž .
Ž .
Ž .
Ž .
96.3 4
77.7 1
Rh 1 –S–C 1
Ž
.
Selected bond lengths and angles for complex IVa
Ž .
Ž .
Ž
.
Ž .
Ž .
108.0 6
C–Rh 1 –S
Ž . Ž .
94.5 4
C 01 –S–C 1
Ž . Ž .
Rh 2 –C 1 –S
Ž .
Ž .
106.7 6
Rh 1 –Rh 2 –C
46.1 4
˚
˚
Ž .
d A
Ž .
d A
Atoms
Atoms
Ž . Ž . Ž .
Ž .
Ž . Ž .
Ž
.
Ž .
Rh 1 –Rh 2 –C 1 79.3 4
Rh 2 –C 1 –C 11 119.0 9
Ž .
Rh 1 –Rh 2
a Bond lengths
Ž . Ž .
Ž . Ž . Ž . Ž .
Ž . Ž . Ž . Ž .
Rh 1 –Rh 2 –C 2 96.5 4
Rh 2 –C 1 –C 2 69.4 7
Ž .
2.630 1
2.306 3
2.10 1
2.14 1
2.19 1
2.19 1
2.18 1
2.21 1
2.21 1
2.299 3
2.02 1
2.23 1
2.19 2
2.16 2
2.15 2
2.20 1
Ž . Ž .
C 1 –F 1
Ž .
1.32 1
Ž . Ž . Ž .
Ž . Ž .
Ž .
Ž
.
Ž .
C–Rh 2 –C 1 93.5 5
C–Rh 2 –C 2 79.1 5
S–C 1 –C 11 109 1
Ž .
Ž .
Ž . Ž .
Ž .
1.28 1
Rh 1 –S
C 1 –F 2
Ž . Ž .
C 1 –F 3
Ž .
Ž . Ž .
Ž .
S–C 1 –C 2 117.5 9
Ž . Ž .
Ž .
Ž .
1.25 1
Rh 1 –C 2
Ž . Ž . Ž . Ž .
Ž
.
Ž . Ž .
Ž .
C 1 –Rh 2 –C 2 41.2 5
C 11 –C 1 –C 2 128 1
Ž . Ž .
Ž .
Ž . Ž .
Ž .
1.43 1
Rh 1 –C 3
C 2 –C 3
Ž . Ž . Ž .
Ž . Ž . Ž .
Ž .
Rh 1 –C–Rh 2 82.5 5
Rh 2 –C 2 –C 1 69.4 7
Ž . Ž .
Ž .
Ž . Ž .
Ž .
1.50 1
Rh 1 –C 7
Ž . Ž .
C 3 –C 4
Ž .
Ž .
Ž .
Ž . Ž .
Ž
.
Ž .
Rh 1 –C–O 143 1
Rh 2 –C 2 –C 21 125 1
Ž . Ž . Ž .
C 1 –C 2 –3C 21 123 1
Ž .
Ž . Ž .
Ž .
1.33 1
Rh 1 –C 8
C 4 –F 4
Ž . Ž .
Ž .
Ž .
Rh 2 –C–O 113 1
X
Ž . Ž .
Ž .
Ž .
1.34 1
Rh 1 –C 9
C 4 –F 5
Ž .
Ž
Ž
.
.
Ž .
Ž . Ž .
Ž .
1.34 1
Rh 1 –C 10
C 4 –F 6
Estimated standard deviations in parentheses.
Ž .
Ž .
Ž . Ž .
Ž .
1.41 2
Rh 1 –C 11
C 7 –C 8
Ž .
Ž .
Ž .
Ž
.
.
Ž .
1.41 2
Rh 2 –S
C 7 –C 11
Ž . Ž .
Ž .
Ž . Ž .
Ž .
1.39 2
Rh 2 –C 2
C 8 –C 9
Ž .
Ž
.
.
.
.
.
Ž .
Ž .
Ž
Ž .
1.39 2
Rh 2 –C 12
C 9 –C 10
.
Ž
w
xq
.
Ž
Ž .
Ž
Ž .
Ž
.
Ž
.
.
.
.
.
.
Ž .
1.36 1
M , 554 65, C10 H10 Rh SPh2
,
477 20,
Rh 2 –C 13
C 10 –C 11
w
Ž
.
xq
.
Ž
2w
xq
.
Ž .
Ž
Ž .
Ž
.
Ž
Ž .
1.38 2
Rh 2 –C 14
C 12 –C 13
C10 H10Rh2 S SPh
100, C10 H10Rh
, 368 25, C10 H10Rh2 S2 , 233
Ž .
Ž
Ž .
Ž
.
Ž
Ž .
1.35 2
xq
.
Rh 2 –C 15
C 12 –C 16
Ž
w
.
Ž .
Ž
Ž .
Ž
.
Ž
Ž .
1.44 3
Rh 2 –C 16
C 13 –C 14
Ž .
Ž .
Ž . Ž
Ž .
1.38 3
S–C 5
1.83 1
Ž .
1.34 2
Ž .
1.51 21
C 14 –C 15
(
)
2.10. Crystallography for complexes IVa, RsEt and
Ž . Ž .
Ž . Ž
C 15 –C 16
Ž .
1.34 3
C 5 –C 6
1
2
3
(
)
Ž . Ž .
VIb, R sH, R sR sMe
C 1 –C 2
Ž .
b
Bond angles
Unique room temperature diffractometer data sets
Ž .
Ž .
Ž . Ž .
Ž .
55.06 8
49.1 2
Ž . Ž .
S–C 5 –C 6
Ž .
117.0 1
Rh 2 –Rh 1 –S
Ž
were measured 2uru scan mode, 2umax 608;
Ž .
Ž .
Ž . Ž . Ž .
C 1 –C 2 –C 3
Ž .
121.3 9
Rh 2 –Rh 1 –C 2
˚
Ž . Ž . Ž .
Ž .
Ž . Ž . Ž .
Ž .
Rh 2 –Rh 1 –C 3
78.0 2
C 1 –C 2 –Rh 1 124.3 7
monochromatic Mo K a radiation, ls0.71073 A; T;
Ž . Ž .
Ž . Ž .
Ž .
Ž . Ž . Ž . Ž .
S–Rh 1 –C 2
83.2 2
C 1 –C 2 –Rh 2 117.4 8
.
295 K , yielding N independent reflections, N0 with
I)3s I being considered ‘observed’ and used in the
Ž .
Ž . Ž . Ž . Ž .
S–Rh 1 –C 3
Ž . Ž . Ž .
78.0 3
Rh 1 –C 2 –Rh 2 79.2 3
Ž . Ž . Ž . Ž .
Ž .
Ž .
C 2 –Rh 1 –C 3
39.5 3
Rh 1 –C 2 –C 3 71.8 5
full-matrix least squares refinement after absorption cor-
rection. Anisotropic thermal parameters were refined for
Ž . Ž .
Ž .
Ž . Ž . Ž .
Ž .
Rh 1 –Rh 2 –S
55.31 7
Rh 2 –C 2 –C 3 121.2 6
Ž .
Ž . Ž .
Ž .
Ž . Ž . Ž .
Ž
.
Rh 1 –Rh 2 –C 2
51.7 2
C 2 –C 3 –C 4
128.3 10
Ž . Ž .
Ž .
Ž . Ž .
Ž .
Ž .
Ž
.
S–Rh 2 –C 2
85.0 3
C 2 –C 3 –Rh 1
Ž . Ž . Ž .
68.7 5
the non-hydrogen atoms, x, y, z, U
being con-
iso
H
Ž .
Ž .
Ž .
Ž .
Rh 1 –S–Rh 2
69.63 8
Rh 1 –C 3 –C 4 119.2 7
strained at estimated values. Neutral atom complex
scattering factors were employed. Pertinent results are
given in Figs. 1 and 2 and Tables 1–3; material de-
posited comprises hydrogen and thermal parameters,
Ž . Ž .
Ž .
111.3 5
Rh 1 –S–C 5
Ž . Ž .
Ž .
108.2 6
Rh 2 –S–C 5
Estimated standard deviations in parentheses.

(
)
202
M.P. DeÕery et al.rJournal of Organometallic Chemistry 551 1998 195–206
full non-hydrogen geometries and structure factor am-
plitudes.
3. Results and discussion
w
Ž
.Ž
The reaction of the complex Cp2 Rh2 m-CO m-
2
2
.x Ž .
h :h -CF3C2CF3 I with a large excess of dimethyl-
sulfane, SMe2 , was carried out in petroleum ether at
room temperature. There was a rapid change of color
from green to cherry red indicating the formation of a
new complex. When solvent and dimethylsulfane were
removed from the red solution under reduced pressure,
Ž .
the starting complex I was the only species recovered,
indicating that a reversible addition of the dimethylsul-
fane had occurred. It was possible to characterize the
addition product in solution by recording spectroscopic
data while excess dimethylsulfane was still present. The
Ž
.
IR and multinuclear NMR results see Section 2 were
consistent with the formation of complex
a
1
1
w
Ž
.Ž
.Ž
.
x
Ž
.
Cp2 Rh2 CO SMe2 m-h :h -CF3C2CF3 IIIa with
the structure shown. The terminal carbonyl absorption
at 1988 cmy1 in the IR spectrum, and the two cyclopen-
tadienyl and two trifluoromethyl resonances in the NMR
spectra, are similar to those in related addition products
Scheme 1. Proposed pathway based on the Stevens rearrangement for
the conversion of a coordinated dimethylsulfane to a bridging
ethanethiolato group.
1
1
w
Ž
. Ž
.
x w x
1 .
of the type Cp2 Rh2 CO L m-h :h -CF3C2CF3
Ž
.
Ž .
The ease with which IIIa converts back to I is
unexpected given the relatively high thermal stability of
some other polynuclear dimethylsulfane complexes.
NMR studies of some dinuclear cyclopentadienyl–
molybdenum complexes, for example, indicate that
dimethylsulfane does dissociate reversibly, but elevated
was a further color change to purple. After removal of
solvent and TLC of the residue, two products were
isolated. The minor product was the dicarbonyl complex
1
1
wŽ
Ž
. Ž
.
x
Ž
.
Cp2 Rh2 CO m-h :h -CF3C2CF3
II, L s CO .
2
Ž
.
w x
temperatures 708C are required 9 . Some rhodium
The major product was characterized from microanaly-
sis and spectroscopic results as Cp2 Rh2 m-h :h -
C CF3 C CF3 H m2-SEt IVa, Rsethyl . Key fea-
tures in the identification of the product were the ab-
sence of a carbonyl absorption in the IR spectrum, and
w
Ž
.
Ž
.x
SMe2
complexes, including Rh6 CO
Rh6 CO SMe2 , are also stable in solution and the
and
1
2
15
w
Ä
w
Ž
. Ž
. x
14
2
Ž
. Ž
.
4
Ž
.
x
Ž
.
w
x
solid state at ambient temperatures 10 .
w
x
Ž
.
the characteristic 11,12 quartet for the C CF3 H proton
plus the AA B3 spin system for the ethanethiolato group
X
in the NMR spectrum. The apparent transformation of
two methyl groups to a single ethyl group and a proton
was so unexpected that the nature of the product was
confirmed by an X-ray crystal structure determination.
w x
A previous communication 5 includes a diagram of the
molecular structure; the structure has been further re-
fined and an alternative view of the molecule is pre-
sented here.
The molecular structure confirms the presence of a
bridging ethanethiolato group which is symmetrically
attached to the rhodium–rhodium bond. The bridging
Ž .
Ž .
and to Rh 1 by a p-bond from C 2 sC 3 ; the Rh 2 –
alkylidene is attached to Rh 2 by a s-bond from C 2
Ž . Ž . Ž . Ž .
˚
Ž .
Ž .
Rh 1 –C 3 p-distances are 2.100 8 and 2.141 9 A,
Ž . Ž .
Ž . Ž .
C 2 s-distance is 2.024 9 A, and the Rh 1 –C 2 and
˚
Ž .
Ž . Ž .
Ž .
Ž
.
When IIIa and excess dimethylsulfane were left in
respectively. The C 2 –C 3 distance for the coordi-
˚
Ž .
nated alkene is 1.43 1 A. The hydrogen atom attached
solution at room temperature for several hours, there

(
)
M.P. DeÕery et al.rJournal of Organometallic Chemistry 551 1998 195–206
203
Ž .
to C 3 was not located. There were no unusual geomet-
ric features within the trifluoromethyl or cyclopentadi-
enyl groups.
Ž
.
Ž
)
We regard the conversion of IIIa to IVa as a
metal-mediated Stevens rearrangement. In the classical
Ž
Ž ..
Stevens rearrangement of sulfonium salts Eq. 1 , a
strong base is needed to deprotonate the alkyl group
w
x
13 .
y
Hq
X
X
R– Sq –CH2 R ™ R–Sq– C HR
<
<
1
Ž .
R
R
In the present system, we propose that the transfer of
Ž
.
electron density from S to Rh in IIIa creates a
pseudo-sulfonium ion, and that the alkyne with its
strongly electron withdrawing substituents serves as the
proton acceptor. Scheme 1 shows a possible pathway
for the rearrangement. Although the zwitter ion shown
in the scheme seems the most likely intermediate in the
Ž
.
Ž
.
conversion of IIIa to IVa , an alternative metalla-
Ž .
cyclic intermediate V cannot be discounted. However,
Ž .
we believe that V would be less likely than the zwitter
ion to rearrange in the required manner. A closely
related 2,3-sigmatropic rearrangement of allyl and
propargyl sulfur ylides has been achieved on a
Ž
.
Ž
.
Scheme 2. Proposed pathway for the conversion of IIIb to IVb .
w
x
Ž .
monomeric rhenium centre 14 . Other base-promoted
rearrangements of coordinated sulfur ligands have been
rearrangement, the reactions between I and other di-
alkylsulfanes were investigated. With diethylsulfane, the
initial addition was again reversible. Indeed, about 30%
of I remained unchanged in solution even with an
w
x
discussed in a recent review 15 .
Ž .
eightyfold excess of the ligand present. The addition
1
1
w
Ž
.Ž
.Ž
.x
product Cp2 Rh2 CO SEt2 m-h :h -CF3C2 CF3
X
Ž
.
IIIb, RsR sethyl was characterized in solution in
the presence of excess diethylsulfane from IR and NMR
results. Over a period of several hours, this complex
transformed into several different species. Separation of
Ž
the products by TLC gave the dicarbonyl complex II,
.
Ž
LsCO in 37% yield, a substantial amount 31%
2
1
.
.
w
Ä
Ž
. Ž .x
.
.
4
Ž
yield of Cp2 Rh2 m-h :h -C CF3 C CF3 H m2-SEt
Ž
Ž
IVa , and a smaller amount 10% yield of the new
2
1
w
Ä
Ž
. Ž
. 4Ž
compound Cp2 Rh2 m-h :h -C CF3 C CF3 H m2-
SCHMeEt IVb .
.
In the formation of the complexes IVa and IVb
w
x
.
x
Ž
.
In a previous investigation 16 , we established that
Ž .
Ž
.
Ž
the reaction between I and diphenylphosphine gave
2
1
w
Ä
Ž
.
w
the proton transfer product Cp2 Rh2 m-h :h -
C CF3 C CF3 H m2-PPh2 . It seemed reasonable to
expect similar behaviour in the reactions between I
from IIIb , there is loss of CO. The formation of II,
Ž
. Ž
.
4
Ž
.x
x
LsCO in this system can be attributed to the facile
Ž .
Ž
.
displacement of coordinated diethylsulfane from IIb
and thiols. When ethanethiol was added to a solution of
I in petroleum ether, there was an immediate color
change from green to crimson. Work up of the reaction
by this free carbon monoxide. It is possible to account
Ž .
Ž
.
for the formation of IVb in terms of another Stevens
rearrangement as shown in Scheme 2. In this reaction, a
proton is transferred from a methylene carbon. We
Ž
mixture gave some of the dicarbonyl complex II, Ls
.
Ž
.
Ž
.
Ž
.
CO and the complex IVa, Rsethyl in 65% yield.
propose that the formation of IVa from IIIb in-
volves transfer of a methyl proton accompanied by
ethene elimination as shown in Scheme 3.
We did not detect the intermediate addition product
1
1
w
Ž
.Ž
.Ž
.x
Cp2 Rh2 CO EtSH m-h :h -CF3C2CF3 , but we ex-
plored the possible formation of such intermediates in
the reaction of I with the less volatile thiol PhSH. The
Ž
.
The complex IVb was also prepared in good yield
43% from the reaction between I and 2-butanethiol.
Ž .
Ž
.
Ž .
Ž
.
results of this investigation are described below.
To test the generality of the metal-mediated Stevens
The carbon attached to sulfur in IVb is chiral. Since
the H and 13C resonances are duplicated in the NMR
1

(
)
204
M.P. DeÕery et al.rJournal of Organometallic Chemistry 551 1998 195–206
fane can be activated, it was of interest to investigate
Ž .
the reaction of I with ethylmethylsulfane. Although
1
1
w
Ž
.Ž
.Ž
the addition product Cp2 Rh2 CO SEtMe m-h :h -
X
.
x
Ž
.
CF3C2CF3 IIIc, Rsethyl, R smethyl was formed,
Ž .
there was always a significant amount of I in the
reaction solution even with an 80-fold excess of the
X
Ž
ligand present. Whereas the complexes IIIa, RsR s
X
.
Ž
.
Me and IIIb, RsR sEt transformed readily to the
Ž
.
m-thiolato complexes IV when left in solution for
X
Ž
.
several hours, IIIc, RsEt, R sMe was reluctant to
undergo a corresponding rearrangement even after 6 h
in solution with excess ligand present. Attempts to force
the conversion by thermal and photochemical means
were also unsuccessful. Two products were isolated in
very low yields from these experiments, and they were
2
1
w
Ä
Ž
. Ž
. 4Ž
identified as Cp2 Rh2 m-h :h -C CF3 C CF3 H m2-
1
.
x
Ž
.
4
S M e
Ž
IV c
a n d
C p 2 R h m -h 2 :h -
w 2 Ä
. Ž
.
Ž
.
x
Ž
.
Ž
.
C CF3 C CF3 CO m2-S VII . The complex IVc is
presumably formed by ethene elimination from the ethyl
group of the coordinated ethylmethylsulfane accompa-
nied by proton transfer. There was no evidence of the
2
1
w
Ä
formation of the complex Cp2 Rh2 m-h :h -
Ž
. Ž
.
4
Ž
.x
C CF3 C CF3 H m2-SPr which would be the product
of a Stevens rearrangement resulting from Hq abstrac-
Ž
.
Ž
.
Scheme 3. Proposed pathway for the conversion of IIIb to IVa .
Ž
.
tion from the methyl group of IIIc . Formation of the
Ž
.
Ž .
spectra of this product see Section 2 , it is evident that
both enantiomers are formed. The intensities of the
appropriate peaks indicate that there are equal amounts
of the two enantiomers. Clearly, there is no enantiose-
complex VII involves total abstraction of the sulfur
Ž
.
from the sulfane ligand. We have identified VII in
Ž .
other reactions of 1 with sulfur containing ligands
including S8, CS2 and isothiocyanates. The characteri-
Ž
.
Ž
.
lectivity in the formation of IVb although the initial
attachment of the thiol is to a chiral rhodium centre. A
second product was isolated in 28% yield from this
reaction, and this green-brown solid was identified as
zation of VII will be presented in a subsequent paper
w x
6 .
To further explore the influence of the alkyl sub-
stituents on these reactions, I was treated with di-n-
Ž .
2
1
w
Ž
.
Ä
Ž
.
Ž
.
4x
Cp2 Rh2 m-CO m-h :h -C CF3 HC CF3 SCHMeEt
propylsulfane, dibenzylsulfane, and di-iso-propylsul-
fane. In solutions containing excess of the ligands di-n-
propylsulfane and dibenzylsulfane, the ratio of the addi-
Ž
.
VIa . There is further comment on the nature of this
and some related complexes below.
w
Ž
.Ž .x
X .Ž
1
1
tion product Cp2 Rh2 CO SRR m-h :h -CF3C2CF3
X
X
n
Ž
.
IIId, RsR sPr ; IIIe, RsR sBz to unchanged
Ž .
Ž
.
Ž
.
I was 4:1 for IIId and 1:3 for IIIe . With di-iso-
propylsulfane, there was no evidence that any addition
product was formed. These observations expose a corre-
lation between the extent of reaction and the steric bulk
of the dialkylsulfane ligand. There was no indication
Ž
.
Ž
.
Ž
that the complexes IIId and IIIe convert to the
.
corresponding m-thiolato complexes IV when left in
solution.
X
Ž
The difference in behaviour of III, RR sMeEt;
X
X
n
.
Ž
RsR sPr or Bz compared to III, RsR sMe or
.
Et is difficult to understand. To determine if steric
factors could have an influence on the ability to form
Ž
.
the m-thiolato complexes IV , we investigated some
Ž .
additional reactions of I with thiols. Five thiols RSH
were chosen with R groups of different bulkiness. In all
n
n
i
t
Ž
cases, the complexes IVd-g, RsPr , Bu , Pr , Bu ,
.
Since the above results indicate that hydrogens on
and Ph were formed readily and isolated in yields
both the a and b carbons of a coordinated dialkylsul-
between 50 and 75%. We conclude that the Stevens

(
)
M.P. DeÕery et al.rJournal of Organometallic Chemistry 551 1998 195–206
205
X
Ž
rearrangement products expected from III, RR sMeEt;
X
RsR sPrn or Bz are capable of being formed, but
.
that the weakness of the dialkylsulfane to rhodium
interaction in these complexes does not support the
required C–H bond activation.
As indicated above in the description of the reaction
Ž
.
with 2-butanethiol, a second product VI can be formed
in these reactions. Complexes of this type were also
obtained in the reactions with PriSH and ButSH. Al-
though the proposed structure is supported by the NMR
Ž
.
results see Section 2 , and the observation of a bridging
carbonyl absorption at 1801 cmy1 in the IR spectrum,
the data could also be fitted to other possible structures.
Consequently, we determined the crystal and molecular
A weak molecular ion was detected in the mass spec-
1
19
Ž
.
trum, and the H and F NMR results see Section 2
were consistent with the proposed formulation. Forma-
1
2
2
Ž
.
structure of complex VIb; R sH, R sR sMe from
Ž
.
tion of VIII results from the coordinative addition of
X-ray diffraction data.
Ž
.
HSPh to the m-thiolato complex IVh ; this results in
loss of the rhodium–rhodium bonding interaction. The
complex was isolated in 45% yield but was not suffi-
ciently stable for further characterization.
The crystal structure established that individual crys-
tals of the compound are optically pure enantiomers;
presumably, the bulk compound is a racemate. The
molecular structure shows that the Rh–Rh bond
Ž
Ž ..
2.662 2 is bridged by a carbonyl and an unsaturated
i
Ž
.
Ž
.
sulfane, Pr SC CF3 sC CF3 H. The latter group is
4. Summary
presumably formed by a 1,2-addition of PriSH to the
Ž .
coordinated alkyne in I . It is attached by a donor bond
Ž
.
Although the coordinative addition products III
2
Ž .
Ž .
from sulfur to Rh 1 and an h -alkene link to Rh 2 .
The individual bond lengths within the dimetallacyclic
unit are within the normal ranges for complexes con-
Ž .
formed from I and dialkylsulfanes are unstable in
solution, they can be investigated when excess ligand is
Ž
.
present. Some of the complexes III undergo interest-
Ž
.
taining the Rh–Rh–CsC–X e.g. XsCO or CR
X
ing Stevens rearrangements when left in solution to
w
x
w x
17,18 and RhSRR 13 units. There is some asymme-
try in the attachment of the carbonyl–Rh bond, with the
Ž
.
form thiolato complexes IV . These rearrangements
occur only for the two most stable addition products
˚
Ž .
Rh 1 –C distance being about 0.15 A shorter than that
for Rh 2 –C. This is presumably due to the different
Ž
.
III , indicating that the metal is intimately involved in
Ž .
the C–H bond activation that leads to rearrangement.
Corresponding additions of the thiols RSH to I lead to
trans-influences of S and the alkene–C.
It is reasonable to expect that the reaction of I with
thiols proceeds through an intermediate addition product
Ž .
Ž .
rapid S–H bond activation and the formation of thiolato
Ž
.
complexes IV . These reactions occur readily with a
wide range of thiols establishing that the unsuccessful
Stevens rearrangements are not blocked by instability of
Ž
.
II, LsRSH . We attempted to substantiate this by
spectroscopic monitoring of the early stages of the
Ž .
reaction between
I and benzenethiol. Although an
2
the likely products.
intermediate with a terminal carbonyl was detected by
IR spectroscopy, the NMR results are not consistent
Ž .
with the structure II . In particular, there is a quartet at
1
d 5.82 in the H NMR spectrum which indicates that
2 Supplementary material. Tables of fractional atomic coordinates,
anisotropic thermal parameters, hydrogen atom parameters, complete
bond lengths and angles and observed and calculated structure factors
are available as supplementary material. JOMC Supplementary Mate-
Ž
.
proton transfer to a C CF3 carbon has already occurred.
The resonances for this intermediate had totally disap-
peared within 20 min, and conversion to the dicarbonyl
1
2
w
Ä
Ž
. Ž
. 4Ž
.
Ž
.
rial: Cp2 Rh2 m-h :h -C CF3 C CF3 H m2-SEt
IVa, R s Et
Ž
.
Ž
complex II, LsCO and the thiolato complex IV,
C16 H16 F6Rh2 S; Table S-IV-1 Atomic parameters; Table S-IV-2
Anisotropic thermal parameters; Table S-IV-3 Hydrogen atom posi-
tional coordinates; Table S-IV-4. Bond lengths; Table S-IV-5 Bond
angles; Table S-IV-6 Structure factors. Molecular projections; JCS
.
RsPh was evident. After 18 h, the NMR results
showed that a new complex had been formed. We
investigated this conversion further.
Ž .
Ž
.
The reaction between I and excess benzene thiol
Chem Comm 1994 1721. JOMC Supplementary Material:
2
1
w
Ä
.Ä
Ž
.
Ž
.
4
Ž
.
Cp2 Rh 2 m-CO m-h :h -CH CF3 C CF3 SCHMe2
VIb ;
was allowed to proceed for several hours before workup.
TLC of the resultant orange solution separated a new
complex that was characterized from spectroscopic data
C18 H18 F6ORh2 S; Table S-VI-1 Atomic parameters; Table S-VI-2
Anisotropic thermal parameters; Table S-VI-3 Hydrogen atom posi-
tional coordinates; Table S-VI-4 Bond lengthsTable S-VI-5. Bond
angles: Table S-VI-6 Structure factors; Crystal structure projection;
Crystal morphology.
1
2
w
Ž
. Ž . x
.Ž
Ž
. Ž
as Cp2 Rh2 m-SPh HSPh m-h :h -C CF3 C CF3 H
VIII .
Ž
.

(
)
206
M.P. DeÕery et al.rJournal of Organometallic Chemistry 551 1998 195–206
w x
9
J. Gabay, S. Dietz, P. Bernatis, M.R. DuBois, Organometallics
Acknowledgements
Ž
.
12 1993 3630.
w
w
w
w
w
w
x
This work has been supported by funds from the
ARC Small Grants Scheme. We thank Monash Univer-
sity for the award of a Graduate Scholarship MPD .
10 S. Rossi, K. Kallinen, J. Pursiainen, T. Pakkanen, T.A. Pakka-
Ž
.
nen, J. Organomet. Chem. 419 1991 219.
x
11 R.S. Dickson, C. Mok, G.N. Pain, J. Organomet. Chem. 66
Ž
.
Ž
.
1979 385.
x
12 R.S. Dickson, G.D. Fallon, S.M. Jenkins, B.W. Skelton, A.H.
Ž
.
White, J. Organomet. Chem. 314 1986 333.
References
x
Ž
.
13 R.K. Olson, J.O. Currie, in: S. Patai Ed. , The Chemistry of the
w x
Ž
.
1
w x
2
R.S. Dickson, Polyhedron 10 1991 1995.
R.S. Dickson, R.J. Nesbit, H. Pateras, J.M. Patrick, A.H. White,
J. Organomet. Chem. 265 1984 C25.
Thiol Group, Part 2, Ch. 12, Wiley, 1974, p. 56.
x
14 P.C. Cagle, A.M. Arif, J.A. Gladysz, J. Am. Chem. Soc. 116
Ž
.
Ž
.
1994 3655.
w x
x
3
R.S. Dickson, R.J. Nesbit, H. Pateras, W. Baimbridge,
15 L. Linford, H.G. Raubenheimer, Adv. Organomet. Chem. 32
Ž
.
Ž
.
Organometallics 4 1985 2128.
1991 1.
w x
4
w
w
x
Ž
.
L. Linford, H.G. Raubenheimer, Adv. Organomet. Chem. 32
16 R.S. Dickson, O.M. Paravagna, Organometallics 11 1992 3196.
Ž
.
x
1991 1.
17 R.S. Dickson, B.M. Gatehouse, M.C. Nesbit, G.N. Pain, J.
w x
5
Ž
.
M.P. Devery, R.S. Dickson, J. Chem. Soc., Chem. Commun.,
Organomet. Chem. 215 1981 97.
Ž
.
w
w
w
x
1994 1721.
18 R.S. Dickson, G.D. Fallon, S.M. Jenkins, R.J. Nesbit,
w x
6
Ž
.
M.P. Devery, R.S. Dickson, B.W. Skelton, A.H. White, unpub-
Organometallics 6 1987 1240.
x
lished results.
19 Texsan, Crystal Structure Analysis Package, Molecular Struc-
w x
7
W.F.L. Amarego, D.D. Perrin, D.R., Perrin, D.R., Purification
of Laboratory Chemicals, 2nd edn., Pergamon, Oxford, 1980.
ture, 1985 and 1992.
x
Ž
.
20 S.R. Hall, H.D. Flack J.M. Stewart Eds. , The XTAL 3.2
User’s Manual, Universities of Westen Australia, Geneva and
Maryland, 1992.
w x
8
Ž
.
R.S. Dickson, S.H. Johnson, G.N. Pain, Org. Synth. 4 1988
283.