Dichalcogenide cleavage and carbonyl insertion reactions on a dirhodium bond

Article abstract of DOI:10.1002/zaac.200700484

The reaction of the binuclear rhodium complex [(η-C₅H ₅)₂Rh₂(μ-CO)(μ-η¹: η¹-C₂(CF₃)₂)] with a series of dichalcogenides, R₂E₂ (E = S, Se, Te; R = Me, Et, i-Pr, Ph, Fc; not all combinations) has provided mixtures of complexes, the majority of which have been characterized by standard spectroscopic techniques. These complexes arise as a consequence of carbonyl substitution followed by chalcogen-chalcogen bond cleavage giving [(η-C₅H ₅)₂Rh₂(μ-ER)2(μ-η¹: η¹-C₂(CF₃)₂)], possibly concomitant with CO insertion into a Rh-C₂(CF₃) ₂ bond of the product in some cases, giving [(η-C ₅H₅)₂Rh₂(CO)(μ-ER) ₂(μ-η¹:η¹-C₂(CF ₃)₂C(O))] (E = Se, Te; R = Me, Et, i-Pr, Ph, Fc; not all combinations). In the case of Te₂R₂ the dichalcogenide products have been structurally characterized for the carbonyl insertion product (for R = Et) and the simple cleavage case (for R = i-Pr). In both, the putative msymmetry is broken by substituent dispositions and, in the R = Et adduct, torsion in the fluorocarbon skeleton.

Full text of DOI:10.1002/zaac.200700484

DOI: 10.1002/zaac.200700484
Dichalcogenide Cleavage and Carbonyl Insertion Reactions on a Dirhodium
Bond
Michael P. Deverya, Ron S. Dicksona, Gary D. Fallona, George A. Koutsantonisb, Brian W. Skeltonb,
and Allan H. Whiteb,*
a Clayton 3800/Victoria, Australia, Monash University, School of Chemistry
b Crawley 6009/Western Australia, The University of Western Australia, Chemistry, M313, School of Biomedical, Biomolecular and
Chemical Sciences
Received October 16th, 2007.
Abstract. The reaction of the binuclear rhodium complex
[(ηϪC5H5)2Rh2(μ-CO)(μ-η1:η1-C2(CF3)2)] with a series of dichal-
cogenides, R2E2 (E ϭ S, Se, Te; R ϭ Me, Et, i-Pr, Ph, Fc; not all
combinations) has provided mixtures of complexes, the majority of
which have been characterized by standard spectroscopic tech-
niques. These complexes arise as a consequence of carbonyl substi-
tution followed by chalcogen-chalcogen bond cleavage giving
[(ηϪC5H5)2Rh2(μ-ER)2(μ-η1:η1-C2(CF3)2)], possibly concomitant
with CO insertion into a Rh-C2(CF3)2 bond of the product in some
cases, giving [(ηϪC5H5)2Rh2(CO)(μ-ER)2(μ-η1:η1-C2(CF3)2C(O))]
(E ϭ Se, Te; R ϭ Me, Et, i-Pr, Ph, Fc; not all combinations). In the
case of Te2R2 the dichalcogenide products have been structurally
characterized for the carbonyl insertion product (for R ϭ Et) and
the simple cleavage case (for R ϭ i-Pr). In both, the putative m-
symmetry is broken by substituent dispositions and, in the R ϭ Et
adduct, torsion in the fluorocarbon skeleton.
Keywords: Insertion; Crystal Structure; Rhodium; Tellurium:
Cleavage Reactions
Introduction
of chalcogenic ligands with transition metals is of major
significance. The existence of several different metal atoms
in an active catalyst provides many potential structural and
chemical alternatives for multisite binding and catalysis of
organic substrates or fragments on the metal particle [13].
The utility of molecular clusters as models for surface
reactivity is based on the assumption that the reactions oc-
curring at the metal surface mimic those taking place in
simple homogeneous systems [14Ϫ17], with soluble spectro-
scopically accessible systems facilitating study, with the ex-
pectation that the reactivity of well-defined complexes will
yield valuable information relating to interaction of the sub-
strate and its transformation [8]. In this report we further
extend our studies on the reaction of organic chalcogenides
[18Ϫ20] with the dirhodium complex [(η-C5H5)2Rh2(μ-
CO)(μ-η2:η2-C2(CF3)2)], (1), as we seek to model the hydro-
dechalcogenization process.
With the oil industry potentially reaching peak production,
the time for the utilisation of more marginal crude oils is
approaching, those typically containing large amounts of
sulfurous compounds which require removal by hydrodesul-
furization over catalysts promoted by dihydrogen. This pro-
cess creates large amounts of noxious H2S and a need for
this to be contained for both environmentally [1, 2] and
industrially important reasons, the removal of chalcogens
ensuring that transition metal catalysts used in reformation
reactions are not poisoned and that the environment is not
polluted [3, 4].
Organometallic complexes, containing two or more ad-
jacent metal atoms, have been proposed as models for
processes occurring at associated metal sites on the surfaces
of heterogeneous catalysts [5Ϫ8], and, because such com-
plexes may display novel reactivity, notably the expectation
of enhanced selectivity, utilising the impact of mutually co-
operative metal atoms on substrate molecules. The role of
metals in dehydrosulfurization has been explored recently
[9Ϫ12] and it has been demonstrated that the interaction
Experimental Section
General experimental conditions
Standard techniques for handling air-sensitive materials were em-
ployed throughout this work [21]. Thin layer chromatography was
performed on Kieselgel 60G: Kielselgel 60HF254 as adsorbent. In-
frared spectra were recorded on a Perkin-Elmer PE 1600 FTIR
spectrometer, and NMR spectra recorded on Bruker DRX400,
AM300 and AC200 instruments. 19F chemical shifts were recorded
relative to internal CFCl3 references, 31P to external H3PO4 (85 %),
and 125Te to external Me2Te. Electron impact mass spectra were
recorded on a VG TRIO-1 GC mass spectrometer operating at
* Prof. Dr. A. H. White
Chemistry, M313
School of Biomedical and Biomolecular and Chemical Sciences
The University of Western Australia
Crawley W. A. 6009/Australia
Tel: (61) 6488 3144
Fax: (61) 6488 1005
e-mail: ahw@chem.uwa.edu.au
´
70 eV and 200 °C inlet temperature. Microanalyses were performed
Z. Anorg. Allg. Chem. 2008, 634, 675Ϫ681
© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
675

M. P. Devery, R. S. Dickson, G. D. Fallon, G. A. Koutsantonis, B. W. Skelton, A. H. White
5
10.3 Hz, 3F, CF3); Ϫ55.3 (q, FFF 10.3 Hz, 3F, CF3). MS: m/z 716 (<1, [M-
by the Campbell Microanalytical Laboratory, University of Otago,
CO]ϩ), 554 (1, [C22H20Rh2S2]ϩ), 477 (<1, [C16H15Rh2S2]ϩ), 368 (<1,
[C10H10Rh2S]ϩ), 233 (12, [C10H10Rh]ϩ), 186 (100, [C12H10S]ϩ).
Dunedin, New Zealand, Chemical and Microanalytical Services,
Essendon, Victoria, or National Analytical Laboratories, Clayton,
Victoria.
This complex slowly converts to 3b over several days.
[(η-C5H5)2Rh2(μ-CO)(μ-η2:η2-C2(CF3)2)], (1), was synthesized by
the reported procedure [22].
(c) With diferrocenyl disulfide
Complex 1 (0.030 g, 0.057 mmol) was dissolved in dichloromethane
(20 ml), and solid diferrocenyl disulfide (0.080 g, 0.184 mmol) was
added in portions with stirring. There was an immediate colour
change to red. After 10 minutes, all volatiles were removed under
vacuum. Tlc with hexane/dichloromethane (1:1 v/v) produced 4
bands. A yellow band (Rf 0.9) was extracted with dichloromethane
and evaporated to dryness to give a yellow solid which was ident-
ified (1H NMR) as trace quantity of 2a.
Reactions of [(η؊C5H5)2Rh2(μ-CO)(μ-η2:η2-
C2(CF3)2)], (1)
(a) With dimethyl disulfide
Complex 1 (0.059 g, 0.112 mmol) was dissolved in diethyl ether
(20 ml), and a large excess of dimethyl disulfide (0.45 g, 4.8 mmol)
was added to the stirring solution. The initially green solution im-
mediately became an orange-red colour. Stirring was continued for
75 minutes, and then all volatiles were removed under vacuum,
leaving an orange solid. Four major bands were separated by TLC
with hexane/dichloromethane (1:1 v/v) as eluent. Two yellow bands
(Rf 0.9) were extracted with dichloromethane and dried under
vacuum, producing yellow solids which were identified (1H NMR)
as cis- and trans-[(η-C5H5)2Rh2(μ-CO)2(μ-η1:η1-C2(CF3)2)] (2a)
(0.015 g, 24 %). A red band (Rf 0.4) decomposed on work-up to
give a yellow solution which was not characterized.
An orange band (Rf 0.1) produced an orange solid which was
characterized as [(η-C5H5)2Rh2(CO)(μ-SFc)2(μ-η1:η1-C2(CF3)2)]
(3c) (0.010 g, 19 %).
1H NMR (CDCl3): δ 5.24 (s, 10H, Rh- C5H5); 4.45 (m, 2H, FeC5H4); 4.34
(m, 2H, FeC5H4); 4.22 (s, 5H, FeC5H5); 4.16 (s, 5H, FeC5H5); 4.07 (m, 4H,
FeC5H4). 19F NMR (CDCl3): δ Ϫ49.6 (s CF3). MS: m/z 932 (2 [M]ϩ); 803
(1, [C28H24F6Rh2S]ϩ); 319 (60 [C10H8FeRhS]ϩ); 233 (100, [C10H10Rh]ϩ).
(d) With diphenyl diselenide
An orange band (Rf 0.5) was extracted with dichloromethane and
solvent evaporated to produce an orange solid which was
characterized as [(η-C5H5)2Rh2(μ-SMe)2(μ-η1:η1-C2(CF3)2)], (3a)
(0.022 g, 34 %). Anal. Calcd. for C16H16F6Rh2S2: C, 32.5;
H,2.7.Found C, 32.5; H, 2.5 %.
Complex 1 (0.028 g, 0.053 mmol) was dissolved in dichloromethane
(20 ml) and an excess of diphenyl diselenide (0.054 g, 0.173 mmol)
was added to the stirring solution. A colour change from green to
orange-red occurred within 10 minutes. After 2 hours, all volatiles
were removed in vacuo leaving an orange-red solid. Tlc with hex-
ane/dichloromethane (3:1 v/v) as eluent separated four main prod-
ucts. The two minor orange products at Rf 0.3-0.4 were not further
characterized. Two yellow bands (Rf 0.9) were extracted with di-
chloromethane evaporated to dryness to give yellow solids which
were identified (1H NMR) as cis- and trans- 2a (0.005 g, 17 %).
A dark orange-red band (Rf 0.7) produced a red solid which was
characterized as [(η-C5H5)2Rh2(μ-SePh)2(μ-η1:η1-C2(CF3)2)] (3d)
(0.022 g, 51 %). Anal. Calcd. for C26H20F6Rh2Se2: C, 38.6; H, 2.5.
Found C, 38.5; H, 2.3 %.
1H NMR (CDCl3): δ 5.16 (s, 10H, C5H5); 2.51 (t, 3JRhH 1.3 Hz, 2.7H, CH3);
3
1
1.78 (t, JRhH 1.7 HZ, 3H, CH3). 13C{IH} NMR (CDCl3): δ 87.6 (d, JRh-C
3.5 Hz, C5H5); 29.5 (s, CH3); 21.9 (s, CH3). 19F NMR (CDCl3): δ Ϫ49.0 (s,
CF3). MS: m/z at 592 (12 %, [M]ϩ); 577 (25, [M-Me]ϩ); 562 (8, [M-2Me]ϩ);
430 (30, [C12H16Rh2S2]ϩ); 415 (80, [C11H13Rh2S]ϩ); 400 (12,
[C10H10Rh2S2]ϩ); 233 (100, [C10H10Rh]ϩ).
(b) With diphenyl disulfide
In
a reaction similar to that described above, 1 (0.020 g,
1H NMR (CDCl3): δ 7.92 (dd, 3JHH 7.8 Hz and 4JHH 1.6 Hz 2H, m-H C6H5);
0.038 mmol) was dissolved in dichloromethane (20 ml), and an ex-
cess of diphenyl disulfide (0.103 g, 0.472 mmol) was added to the
stirring solution. A slow reaction occurred, and was not complete
for 24 hours. Four major bands were isolated by TLC with hexane/
dichloromethane (1:1 v/v) as eluent. Two yellow bands (Rf 0.9) were
extracted with dichloromethane and evaporated to dryness to give
yellow solids which were identified (1H NMR) as cis- and trans- 2a
(total yield 0.003 g, 14 %). An orange band (Rf 0.7) was extracted
with dichloromethane, and produced an orange solid which was
characterized as [(η-C5H5)2Rh2(μ-SPh)2(μ-η1:η1-C2(CF3)2)] (3b)
(0.026 g, 33 %).
3
4
7.44 (dd, JHH 8.2 Hz and JHH 1.3 Hz, 2H, m-H C6H5); 7.31 (m, 3H, o-, p-
H, C6H5); 7.16 (m, 3H, o-, p-H, C6H5); 5.07 (s, 10H, C5H5). 19F NMR
(CDCl3):
δ
Ϫ49.9 (s, CF3). MS: m/z 812 (2 % [M]ϩ); 655 (25,
[C20H15F6Rh2Se]ϩ); 570 (10, [C22H20Rh2Se]ϩ); 493 (12, [C16H15Rh2Se]ϩ);
431 (8, [C5H5Rh2Se2]ϩ); 325 (35, [C11H10RhSe]ϩ); 233 (100, [C10H10Rh]ϩ).
An orange band (Rf 0.2) produced an orange solid which
was characterized as as [(η-C5H5)2Rh2(CO)(μ-SePh)2(μ-η1:η1-
C2(CF3)2C(O))] (4a) (0.010 g, 23 %).
IR (CH2Cl2): ν(CO) 1618 cmϪ1
.
1H NMR (CDCl3): δ 8.10 (dd, JHH 7.6 Hz
3
4
3
4
and JHH 1.6 Hz, 2H, o-H, C6H5); 7.72 (dd, JHH 5.7 Hz and JHH 3.2 Hz,
3
4
2H, o-H, C6H5); 7.52 (dd, JHH 5.7 Hz and JHH 3.2 Hz, 1H, p-H, C6H5);
7.35 (m, 2H, C6H5); 7.16 (m, m-, p-HI 3H, C6H5); 5.15 (s, 5H, C5H5); 5.09
(s, 5H, C5H5). 19F NMR (CDCl3): δ Ϫ50.9 (q, 5JFF 15.3 Hz, 3F, CF3); Ϫ55.8
3
1H NMR (d6-acetone): δ 8.10 (d, JHH 7.8 Hz, 2H); 7.50 (m, 2H); 7.39 (m,
3H); 7.11 (m, 3H); 5.16 (s, 10H, C5H5). 19F NMR (CDCl3): δ Ϫ49.9 (s, CF3).
MS: m/z 716 (12 %, [M]ϩ), 639 (1, [M-Ph]ϩ), 607 (8, [C20H15F6Rh2S]ϩ), 554
(34, [C22H20Rh2S2]ϩ), 477 (10, [C16H15Rh2S2]ϩ), 368 (12, [C10H10Rh2S]ϩ),
233 (100, [C10H10Rh]ϩ).
5
(q, JFF 15.3 Hz, 3F, CF3). MS: m/z 655 (10, [C20H15F6Rh2Se]ϩ); 570 (4,
[C22H20Rh2Se]ϩ); 493 (4, [C16H15Rh2Se]ϩ); 325 (35, [C11H10RhSe]ϩ); 233
(100, [C10H10Rh]ϩ).
A brown band (Rf 0.2) was extracted with dichloromethane
and produced a brown solid which was characterized as [(η-
C5H5)2Rh2(CO)(η1-S2Ph2)(μ-η1:η1-C2(CF3)2)] (2b) (0.022 g, 27 %).
(e) With diferrocenyl diselenide
Complex 1 (0.043 g, 0.082 mmol) was dissolved in dichloromethane
(20 ml). Solid diferrocenyl diselenide (0.059 g, 0.112 mmol) was ad-
ded in portions with stirring. There was an immediate colour
IR (CH2Cl2): ν(CO) 1989s; ν (CϭC) at 1618m cmϪ1 1H NMR (CDCl3): δ
.
8.10 (d, 3JHH 7.8 Hz, 2H); 7.50 (m, 2H); 7.39 (m, 3H); 7.11 (m, 3H); 5.46 (s,
5
5H, C5H5); 5.35 (broad s, 5H, C5H5). 19F NMR (CDC13): δ Ϫ51.3 (q, FFF
676
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Z. Anorg. Allg. Chem. 2008, 675Ϫ681

Dichalcogenide Cleavage and Carbonyl Insertion Reactions on a Dirhodium Bond
change to red. Stirring was continued for 10 minutes, then all vol-
(g) With diethyl ditelluride
atiles were removed under vacuum. TLC with hexane/dichloro-
methane (1:1 v/v) produced three bands. A yellow band (Rf 0.9)
was extracted with dichloromethane, and evaporated to dryness to
give a yellow solid which was identified (1H NMR) as 2a (trace
quantity).
In a reaction similar to that described above, complex 1 (0.030 g,
0.057 mmol) was dissolved in dichloromethane (20 ml), and an ex-
cess of diethyl ditelluride (0.102 g, 0.326 mmol) was added to the
stirring solution. An immediate colour change from green to dark
orange occurred. The mixture was stirred for 2 hours. All volatiles
were then removed, leaving an orange solid. TLC with hexane/di-
chloromethane (1:1 v/v) separated seven bands.
A red band (Rf 0.4) was similarly worked up to produce a red
solid which was characterized as [(η-C5H5)2Rh2(μ-SeFc)2(μ-η1:η1-
C2(CF3)2)] (3e) (0.030 g, 36 % yield). Anal. Calcd. for
C34H28F6Fe2Rh2Se2: C, 39.8; H, 2.8. Found C, 39.4; H, 2.5 %.
1H NMR (CDCl3): δ 5.21 (s, 10H, RhC5H5); 4.38 (m, 2H, FeC5H4); 4.31 (m,
2H, FeC5H4); 4.22 (s, 5H, FeC5H5); 4.15 (s, 5H, FeC5H5); 4.10 (m, 4H,
FeC5H4). 19F NMR (CDCl3): δ Ϫ49.5 (s, CF3). MS: m/z 763 (24 %, [M-
SeFc]ϩ); 578 (5, [C14H10F6Rh2Se]ϩ); 433 (10, [C15H14FeRhSe]ϩ); 233 (100,
[C10H10Rh]ϩ).
An orange band (Rf 0.9) was extracted with dichloromethane, and
evaporation of the solvent left an orange oil which was identified
(1H NMR) as excess diethyl ditelluride.
A yellow band (Rf 0.8) was similarly worked up and produced a
small quantity of a yellow solid which was identified (IR) as 2a.
A red band (Rf 0.7) was similarly worked up and produced a red
solid which was identified [(η-C5H5)2Rh2(μ-TeEt)2(μ-η1:η1-
C2(CF3)2)] (3g) (0.024 g, 15 % yield).
An orange band (Rf 0.1) was similarly worked up to produce an
orange solid which was characterized as [(η-C5H5)2Rh2(CO)(μ-
SeFc)2(μ-η1:η1-C2(CF3)2C(O))] (4b) (0.010 g, 12 % yield).
3
1H NMR (CDCl3): δ 5.20 (s, 10H, C5H5); 2.42 (q, 2H, JHH 7.6 Hz, CH2);
IR (CH2Cl2): ν(CO) 1598 cmϪ1 1H NMR (CDCl3): δ 5.49 (s, 5H, RhC5H5);
.
2.36 (q, 2H, 3JHH 6.8 Hz, CH2); 1.42 (t, 3H, 3JHH 7.6 Hz, CH3); 1.22 (q, 3H,
3JHH 6.8 Hz, CH3). 19F NMR (CDCl3): δ Ϫ49.4 (s, CF3). Mass spectrum:
m/z at 812 (<1 %, [M]ϩ); 783 (7, [M-Et]ϩ); 754 (1, [M-2Et]ϩ); 628 (6,
[C14H10F6Rh2Te]ϩ); 592 (8, [C10H10Rh2Te2]ϩ); 527 (4, [C5H5Rh2Te2]ϩ); 466
(3, [C10H10Rh2Te]ϩ); 424 (5, [C5H5RhTe2]ϩ) ; 233 (100, [C10H10Rh]ϩ).
5.05 (s, 5H, RhC5H5); 4.38 (m, 2H, FeC5H4); 4.31 (m, 2H, FeC5H4); 4.22 (s,
5H, FeC5H5); 4.13 (s, 5H, FeC5H5); 4.13 (m, 4H, FeC5H4). 19F NMR
5
5
(CDC13): δ Ϫ51.0 (q, JFF 15.0 Hz, 3F, CF3); Ϫ55.4 (q, JFF 15.0 Hz, 3F,
CF3). Mass spectrum: m/z at 763 (20, [M-SeFc-CO]ϩ); 578 (10,
[C14H10F6Rh2Se]ϩ); 433 (12, [C15H14FeRhSe]ϩ); 233 (100, [C10H10Rh]ϩ).
An orange band (Rf 0.3) was similarly worked up and produced an
orange solid which was identified as [(η-C5H5)2Rh2(CO)(μ-
TeEt)2(μ-η1:η1-C2(CF3)2C(O))] (4d) (0.041 g, 58 % yield).
On standing, 4b slowly converted to an alternative form, 4bЈ. The
conversion occurred over several weeks, and did not appear to ac-
celerate when the complex was left in solution.
IR (CH2C12): ν(CO) 1597 cmϪ1
.
1H NMR (CDCl3): δ 5.36 (s, 5H, C5H5);
IR (CH2C12): ν(CO) at 1600 cmϪ1 1H NMR (CDCl3): δ 5.49 (s, 5H,
.
5.32 (s, 5H, C5H5); 2.56 (q, 2H, 3JHH 7.7 Hz, CH2); 2.11 (q, 2H, 3JHH 7.7 Hz,
RhC5H5); 5.41 (s, 5H, RhC5H5); 4.38 (m, 2H, FeC5H4); 4.30 (m, 2H,
FeC5H4); 4.19 (s, 5H, FeC5H4); 4.13 (s, 5H, FeC5H5); 4.10 (m, 4H, FeC5H4).
3
3
CH2); 1.47 (t, 3H, JHH 7.7 Hz, CH3); 1.04 (q, 3H, JHH 7.7 HZ, CH3). 19F
5
5
NMR (CDCl3): δ Ϫ50.6 (q, 3F, JFF 15.3 HZ, CF3); Ϫ55.1 (q, 3F, JFF
15.3 HZ, CF3). Mass spectrum: m/z 812 (<1 %, [M-CO]ϩ); 783 (3,
[C16H15F6Rh2Te2]ϩ); 754 (1, [C14H10F6Rh2Te2]ϩ); 650 (2, [C14H20Rh2Te2]ϩ);
628 (4, [C14H10F6Rh2Te]ϩ); 592 (5, [C10H10Rh2Te2]ϩ); 527 (3,
[C5H5Rh2Te2]ϩ); 466 (3, [C10H10Rh2Te]ϩ); 424 (5, [C5H5RhTe2]ϩ) ; 233 (100,
[C10H10Rh]ϩ). Crystals of 4d were grown by slow evaporation of a dichloro-
methane solution of the complex.
5
5
19F NMR (CDC13): δ Ϫ51.4 (q, JFF 15.0 Hz, 3F, CF3); Ϫ55.8 (q, JFF
15.0 Hz, 3F, CF3). The mass spectrum was identical to that for 4b.
(f) With dimethyl ditelluride
In a reaction similar to that described above, complex 1 (0.032 g,
0.061 mmol) was dissolved in dichloromethane (20 ml), and an ex-
cess of dimethyl ditelluride (0.07 g, 0.25 mmol) was added to the
stirring solution. After stirring for 30 minutes, the volatiles were
removed and three major bands were separated by TLC. An orange
band (Rf 0.9) was extracted with dichloromethane, and evaporation
of the solvent left an orange oil which was identified (1H NMR)
as unreacted dimethyl ditelluride.
(h) With diisopropyl ditelluride
In a reaction similar to that described above, complex 1 (0.044 g,
0.084 mmol) was dissolved in dichloromethane (20 ml). An excess
of diisopropyl ditelluride (0.10 g, 0.29 mmol) was added dropwise
with stirring. There was an immediate colour change to reddish
orange. Stirring was continued for 30 minutes, then all volatiles
were removed under vacuum. TLC with hexane/dichloromethane
(1:1 v/v) produced four bands.
A red band (Rf 0.7) was similarly worked up and produced a red
solid which was identified as [(η-C5H5)2Rh2(μ-TeMe)2(μ-η1:η1-
C2(CF3)2)] (3f) (0.020 g, 42 % yield).
1H NMR (CDCl3): δ 5.17 (s, 10H, C5H5); 1.77 (s, 3H, CH3); 1.76 (s, 3H,
CH3). 19F NMR (CDC13): δ Ϫ49.8 (s, CF3). Mass spectrum: m/z 784 (4 %,
[M]ϩ); 769 (24, [M-Me]ϩ); 643 (5, [M-TeMe]ϩ); 628 (5, [C14H10F6Rh2Te]ϩ);
592 (4, [C10H10F6Rh2Te2]ϩ; 464 (4, [C10H10Rh2Te]ϩ); 233 (100,
[C10H10Rh]ϩ).
An orange band (Rf 0.9) was identified (1H NMR) as unreacted
diisopropyl ditelluride (trace quantity).
A yellow band (Rf 0.8) was identified (1H NMR) as 2a (trace quan-
tity).
A red band (Rf 0.7) produced a red solid which was identified as
[(η-C5H5)2Rh2(μ-Te(i-Pr))2(μ-η1:η1-C2(CF3)2)] (3h) (0.24 g, 34 %
yield).
An orange band (Rf 0.3) was similarly worked up and produced an
orange solid which was identified as [(η-C5H5)2Rh2(CO)(μ-
TeMe)2(μ-η1:η1-C2(CF3)2C(O))] (4c) (0.015 g, 30 % yield).
3
1H NMR (CDCl3): δ 5.22 (s, 10H, C5H5); 3.07 (septet, JHH 7.2 Hz, 1H,
3
3
IR (CH2Cl2): ν(CO) 1599 cmϪ1
.
1H NMR (CDCl3): δ 5.40 (s, 5H, RhC5H5);
CH); 2.79 (septet, JHH 7.2 Hz, 1H, CH); 1.45 (d, JHH 7.2 Hz, 6H, CH3);
5.32 (s, 5H, RhC5H5); 1.89 (s, 3H, CH3); 1.70 (s, 3H, CH3). 19F NMR
1.33 (d, JHH 7.2 Hz, 6H, CH3). 19F NMR (CDCl3): δ Ϫ52.1 (s, CF3). Mass
3
5
5
(CDCl3): δ Ϫ50.6 (q, JFF 15.3 Hz, 3F, CF3); Ϫ55.1 (q, JFF 15.3 Hz,
3F, CF3). Mass spectrum: m/z at 784 (45, [M-CO]ϩ); 769 (22,
spectrum: m/z 797 (4 %, [M-Pr]ϩ); 754 (2, [C14H10F6Rh2Te2]ϩ); 628 (4,
[C14H10F6Rh2Te]ϩ); 592 (10, [C10H10Rh2Te]ϩ); 527 (2, [C5H5Rh2Te2]ϩ); 462
(4, [Rh2Te2]ϩ); 424 (2, C5H5RhTe2); 233 (100, [C10H10Rh]ϩ). Crystals of 3h
were grown by slow evaporation of a dichloromethane solution of the com-
plex.
[C15H13F6Rh2Te2]ϩ);
643
(10,
[C15H13F6Rh2Te]ϩ);
628
(8,
[C14H10F6Rh2Te]ϩ); 592 (8, [C10H10Rh2Te2]ϩ); 464 (4, [C10H10Rh2Te]ϩ); 233
(100, [C10H10Rh]ϩ).
Z. Anorg. Allg. Chem. 2008, 675Ϫ681
© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.zaac.wiley-vch.de
677

M. P. Devery, R. S. Dickson, G. D. Fallon, G. A. Koutsantonis, B. W. Skelton, A. H. White
An orange band (Rf 0.3) produced an orange solid which
was identified as
[(η-C5H5)2Rh2(CO)(μ-Te(i-Pr))2(μ-η1:η1-
C2(CF3)2C(O))] (4e) (0.041 g, 56 % yield).
stirring, after 10 minutes all volatiles were removed under vacuum.
TLC with hexane/dichloromethane (1:1 v/v) produced four bands.
An orange band (Rf 0.9) was extracted with dichloromethane, and
evaporation of the solvent produced an orange solid which was
identified (1H NMR) as excess diferrocenyl ditelluride (trace quan-
tity).
IR (CH2C12): ν(CO) 1599m cmϪ1
.
1H NMR (CDCl3): δ 5.38 (s, 5H, C5H5);
3
3
5.36 (s, 5H, C5H5); 2.92 (septet, JHH 7.1 Hz, 1H, CH); 2.70 (septet, JHH
3
3
7.2 Hz, 1H, CH); 1.55 (d, JHH 7.1 HZ, 3H, CH3); 1.46 (d, JHH 7.2 Hz, 3H,
3
3
CH3); 1.15 (d, JHH 7.1 Hz, 3H, CH3); 1.10 (d, JHH 7.2 Hz, 3H, CH3).
5
5
19F NMR (CDCl3): δ Ϫ50.5 (q, JFF 5.4 Hz, 3F, CF3); Ϫ55.2 (q, JFF
15.4 Hz, 3F, CF3). Mass spectrum: m/z at 825 (2 %, [M-CO]ϩ); 797
(2 %, [C17H17F6Rh2Te2]ϩ); 754 (2, [C14H10F6Rh2Te2]ϩ); 628 (3,
[C14H10F6Rh2Te]ϩ); 592 (8, [C10H10Rh2Te2]ϩ); 527 (4, [C5H5Rh2Te2]ϩ); 462
(6, [Rh2Te2]ϩ); 424 (6, C5H5RhTe2); 233 (100, [C10H10Rh]ϩ).
A yellow band (Rf 0.8) was similarly worked up and produced a
yellow solid which was identified (1H NMR) as 2a (trace quantity).
A red band (Rf 0.4) was similarly worked up and produced a red
solid which was identified as [(η-C5H5)2Rh2(μ-TeFc)2(μ-η1:η1-
C2(CF3)2)] (3j) 0.040 g, 30 % yield). Anal. Calcd. for
C34H28F6Fe2Rh2Te2: C, 36.4; H, 2.5; F, 10.1 %. Found C, 36.3; H,
2.6; F, 10.3 %.
1H NMR (CDCl3): δ 5.25 (s, 10H, RhC5H5); 4.28 (m, 4H, FeC5H4); 4.21 (s,
5H, FeC5H5); 4.18 (m, 4H, FeC5H4); 4.17 (s, 5H, FeC5H5). 19F NMR
(CDCl3): δ Ϫ50.1 (s, CF3). Mass spectrum: m/z at 813 (9 %, [M-TeFc]ϩ);
651 (6, [C20H19FeF6Rh2Te]ϩ); 498 (15, [C10H10Fe2Te2]ϩ); 353 (55,
[C15H14FeRh]ϩ); 233 (85, [C10H10Rh]ϩ); 186 (100, [C10H10Fe]ϩ).
(i) With diphenyl ditelluride
A slight excess of diphenyl ditelluride (0.028 g, 0.068 mmol) was
added in portions over 2 minutes to a stirred solution of complex
1 (0.031 g, 0.059 mmol) in dichloromethane (20 ml) after 2 hours
all volatiles were then removed, leaving a reddish-orange solid.
TLC with hexane/dichloromethane (1:1 v/v) as eluent separated
seven bands. Each band was extracted with dichloromethane and
solvent was removed under vacuum.
A red band (Rf 0.5) was similarly worked up and produced a red
solid which was identified as an alternative form of [(η-
C5H5)2Rh2(μ-TeFc)2(μ-η1:η1-C2(CF3)2)] (3jЈ) (0.010 g, 8 % yield).
1H NMR (CDCl3): δ 5.25 (s, 10H, RhC5H5); 4.13 (s, 10H, FeC5H5); 4.05 (m,
4H, FeC5H4); 3.84 (m, 4H, FeC5H4). 19F NMR (CDCl3): δ Ϫ49.9 (s, CF3).
Mass spectrum: m/z 813 (15 %, [M-TeFc]ϩ); 651 (10, [C20H19FeF6Rh2Te]ϩ);
498 (10, [C10H10Fe2Te]ϩ); 353 (65, [C15H14FeRh]ϩ); 233 (100, [C10H10Rh]ϩ);
186 (60, [C10H10Fe]ϩ)).
An orange band (Rf 0.9) was extracted with dichloromethane, and
evaporated to dryness, producing an orange solid which was ident-
ified (1H NMR) as unreacted diphenyl ditelluride (trace quantity).
Two yellow bands (Rf 0.8) were similarly worked up and produced
yellow solids which were identified (1H NMR) as cis- and trans- 2a
(total yield 0.005 g, 17 %).
An orange band (Rf 0.1) produced an orange solid which was
identified as [(η-C5H5)2Rh2(CO)(μ-Fc2(μ-η1:η1-C2(CF3)2C(O))]
(4g) (0.015 g, 11 % yield).
A dark orange-red band (Rf 0.7) produced a red solid which was
characterized as [(η-C5H5)2Rh2(μ-TePh)2(μ-η1:η1-C2(CF3)2)] (3i)
(0.010 g, 19 %).
IR (CH2C12): ν(CO) 1604 cmϪ1. 1H NMR (CDCl3): δ 5.53 (s, 5H, RhC5H5);
3
3
1H NMR (CDCl3): δ 7.72 (d, JHH 7.0 Hz, 2H, o-H, C6H5); 7.55 (d, JHH
7.0 HZ, 2H, o-H, C6H5Ј); 7.34 (m, 1H, p-H, C6H5); 7.26 (m, 1H, p-H, C6H5);
7.21 (m, 2H, m-H, C6H5); 7.11 (m, 2H, m-H, C6H5Ј); 5.16 (s, 10H, C5H5).
5.13 (s, 5H, RhC5H5); 4.1-4.4(m, 8H, FeC5H4); 4.20 (s, 5H, FeC5H5); 4.14
5
(s, 5H, FeC5H5). 19F NMR (CDCl3): δ Ϫ50.6 (q, 3F, JFF 15.4 HZ, CF3);
5
Ϫ55.2 (q, 3F, JFF 15.4 HZ, CF3). Mass spectrum: m/z 813 (10 %, [M-
19F NMR (CDCl3): δ Ϫ50.5 (s, CF3). 125Te NMR (CDCl3): δ Ϫ7 (d, JTeRh
1
TeFc]ϩ); 651 (10, [C20H19FeRh2Te]ϩ); 498 (20, [C10H10Fe2Te2]ϩ); 353 (40,
[C15H14FeRh]ϩ); 233 (90, [C10H10Rh]ϩ); 186 (100, [C10H10Fe]ϩ).
1
87 Hz, TePh); Ϫ115 (dd, JTeRh
ഠ
1JTeRhЈ 76 Hz, TePh). Mass spectrum: m/z
908
(
<1 %, [M]ϩ); 831 (2, [M-Ph]ϩ); 705 (2, [M- TePh]ϩ); 628 (4,
[C14H10F6Rh2Te]ϩ); 604 (2, [C11H10Rh2Te2]ϩ); 462 (4, [Rh2Te2]ϩ); 233
(100, [C10H10Rh]ϩ).
On standing 4g slowly converted to an alternative form 4gЈ. The
conversion occurred in the solid state over several weeks and did
not appear to accelerate in solution.
An orange band at Rf 0.2 produced an orange solid which
was characterized as [(η-C5H5)2Rh2(CO)(μ-Te(i-Pr))2(μ-η1:η1-
C2(CF3)2C(O))] (4f) 0.037 g, 69 %). Anal. Calcd. for
C27H20F6ORh2Te2: C, 34.7; H, 2.2; F, 12.2. Found C, 36.1; H, 2.1;
F, 11.4 %.
IR (CH2C12): ν(CO) 1604 cmϪ1. 1H NMR (CDCl3): δ 5.53 (s, 5H, RhC5H5);
5.28 (s, 5H, RhC5H5); 4.1-4.5 (m, 8H, FeC5H4); 4.20 (s, 5H, FeC5H5); 4.15
5
(s, 5H, FeC5H5). 19F NMR (CDCl3): δ Ϫ43.9 (q, 3F, JFF 13.4 HZ, CF3);
Ϫ54.6 (q, 3F, 5JFF 13.4 HZ, CF3). Mass spectrum: m/z 813 (5 %, [M-TeFc]ϩ);
651 (4, [C20H19FeRh2Te]ϩ); 498 (20, [C10H10Fe2Te2]ϩ); 353 (33,
[C15H14FeRh]ϩ); 233 (85, [C10H10Rh]ϩ); 186 (100, [C10H10Fe]ϩ).
3
IR (CH2Cl2): ν(CO) 1608m cmϪ1
.
1H NMR (CDCl3): δ 7.86 (dd, JHH
8.0 Hz, 4JHH 1.2 HZ, 2H, o-H, C6H5); 7.39 (t, 3JHH 6.2 HZ, 1H, p-H, C6H5);
7.06 (m, 2H, m-H, C6H5); 7.2-7.3 (m, 5H o-,m-,p-H, C6H5Ј); 5.30 (s, 5H,
C5H5); 5.15 (s, 5H, C5H5). 1H NMR (d6-acetone): δ 8.02 (d, JHH 7.0 Hz,
3
Structure determination of 4d
3
2H, o-H, C6H5); 7.50 (t, JHH 7.2 Hz, 1H, p-H, C6H5); 7.3-7.4 (m, 4H o,m-
H, C6H5); 7.20 (t, 1H, p-H C6H5Ј); 7.02 (m, 2H, m-H, C6H5); 5.40 (s, 5H,
A full sphere of CCD area-detector diffractometer data was meas-
5
C5H5); 5.30 (s, 5H, C5H5). 19F NMR (CDCl3): δ Ϫ50.6 (q, JFF 5.5 Hz, 3F,
´
5
CF3); Ϫ55.8 (q, JFF 5.5 Hz, 3F, CF3). 125Te NMR (CDCl3): δ Ϫ246 (dd,
ured (ω-scans, 2θmax ϭ 70°; monochromatic Mo Kα radiation, λ ϭ
1
1JTeRh
ഠ
1JTeRhЈ 97 HZ, TePh); Ϫ8 (dd, JTeRh
ഠ
1JTeRhЈ 75 Hz). Mass spec-
˚
0.71073 A; T ca. 100 K), yielding 44424 reflections, these merging
trum: m/z at 908 (<1 %, [M-CO]ϩ); 705 (5, [C20H15F6Rh2Te2]ϩ); 628 (2,
[C14H10F6Rh2Te]ϩ); 604 (2, [C11H10Rh2Te2]ϩ); 462 (3, [Rh2Te2]ϩ); 233
(100, [C10H10Rh]ϩ).
to 9495 unique (Rint ϭ 0.027) after ’empirical’/multiscan absorption
correction (proprietary software; μMo ϭ 4.2 mmϪ1; specimen: 0.37
x 0.31 x 0.19 mm; ’T’min/max ϭ 0.63), 8895 with F > 4σ(F) being
considered ’observed’ and used in the full matrix least squares re-
finement, refining anisotropic displacement parameters for the
non-hydrogen atoms, (x,y,z,Uiso H
) being included, following a rid-
(j) With diferrocenyl ditelluride
ing model. Conventional residuals on F2 at convergence are R1 ϭ
In a reaction similar to that described above, complex 1 (0.062 g,
0.118 mmol) was dissolved in dichloromethane (20 ml). Diferro-
cenyl ditelluride (0.070 g, 0.112 mmol) was added in portions with
0.028, wR2 ϭ 0.067 (weights: (σ2(F2) ϩ (0.0202P)2 ϩ 9.5945P)Ϫ1
)
(P ϭ (F2o ϩ 2F2c)/3, xabs refining to 0.04(2). Neutral atom complex
scattering factors were employed within the SHELXL-97 program
678
www.zaac.wiley-vch.de
© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Z. Anorg. Allg. Chem. 2008, 675Ϫ681

Dichalcogenide Cleavage and Carbonyl Insertion Reactions on a Dirhodium Bond
[23]. Pertinent results are given below and in Table 1 and Fig. 1. A
full .cif deposition resides with the Cambridge Crystallographic
Data Centre, CCDC 615216. Copies may be obtained free of
charge on application to The Director CCDC, 12 Union Road,
Cambridge CB2 1EX, UK (Fax: int. code ϩ (1223) 336-033;
email for inquiry: fileserv@ccdc.cam.ac.uk; email for deposition:
deposit@ccdc.cam.ac.uk).
Table 1 Selected geometries, 4d
Atoms
Parameter
Atoms
Parameter
˚
Distances/A
Rh(1)-Te(1)
Rh(1)-Te(2)
Rh(1)-C(2)
Rh(1)-C(cp)
2.5873(5)
2.5756(5)
2.095(4)
2.220(5)
Ϫ2.253(4)
1.876
Rh(2)-Te(1)
Rh(2)-Te(2)
Rh(2)-C(5)
Rh(2)-C(cp)
2.5755(4)
2.5774(5)
1.991(4)
2.241(4)
Ϫ2.287(5)
1.907
Rh(1)-C(100)
Rh(2)-C(200)
Te(1)-C(11)
C(3)-C(2)
C(1)-C(2)
2.169(4)
1.362(6)
1.512(6)
Te(2)-C(21)
C(3)-C(5)
C(3)-C(4)
C(5)-O(5)
2.170(4)
1.512(6)
1.530(5)
1.227(6)
Angle/degrees
Fig. 1 Projection of a single molecule of 4d, showing atom label-
C(100)-Rh(1)-Te(1)
C(100)-Rh(1)-Te(2)
C(100)-Rh(1)-C(2)
C(2)-Rh(1)-Te(1)
C(2)-Rh(1)-Te(2)
Te(1)-Rh(1)-Te(2)
Rh(1)-Te(1)-Rh(2)
C(11)-Te(1)-Rh(1)
C(21)-Te(2)-Rh(1)
Rh(1)-C(2)-C(3)
Rh(1)-C(2)-C(1)
C(1)-C(2)-C(3)
127.0
124.3
131.9
C(200)-Rh(2)-Te(1)
C(200)-Rh(2)-Te(2)
C(200)-Rh(2)-C(5)
C(5)-Rh(2)-Te(1)
C(5)-Rh(2)-Te(2)
Te(1)-Rh(2)-Te(2)
Rh(1)-Te(2)-Rh(2)
C(11)-Te(1)-Rh(2)
C(21)-Te(2)-Rh(2)
Rh(2)-C(5)-C(3)
Rh(2)-C(5)-O(5)
C(3)-C(5)-O(5)
128.1
131.8
126.1
ling and 50 % probability amplitude displacement ellipsoids for the
˚
non-hydrogen atoms; hydrogen atoms have arbitrary radii of 0.1 A.
82.8(1)
93.0(1)
82.27(2)
93.54(2)
103.9(1)
104.8(1)
128.9(3)
114.1(3)
116.7(4)
126.3(4)
124.6(4)
89.7(1)
83.2(1)
82.54(2)
93.68(2)
98.1(1)
107.4(1)
127.6(3)
118.5(3)
113.8(4)
109.0(4)
[(η-C5H5)2Rh2(CO)(μ-Te(i-Pr))2(μ-η1:η1-C2(CF3)2C(O))], (4)
and in only one case, in the reaction of Ph2S2, was the coor-
dination adduct found, viz. [(η-C5H5)2Rh2(μ-CO)(S2Ph2)(μ-
η1:η1-C2(CF3)2)], (2b). The isolation of this latter complex
gives some insight into the nascent reaction mechanism
where coordination of the dichalcogen is required, followed
by subsequent cleavage and insertion reactions, Scheme 1.
It is of interest that the reaction of the disulfides did not
result in the isolation of complexes analogous to 4 while the
diselenides and ditellurides all gave moderate to low yields
of the insertion product. Previously, we have shown that
the reaction of dialkyl sulfides, SRRЈ to [(η-C5H5)2Rh2(μ-
CO)(μ-η2:η2-C2(CF3)2)] (1) proceeded by coordination of
the sulfide [19, 20] and giving [(η-C5H5)2Rh2(μ-CO)(μ-
η1:η1-C2(CF3)2)(SRRЈ)], a reaction which was reversible.
On prolonged contact with SR2 (R ϭ Me, Et) interesting
transformations occurred, giving [(η-C5H5)2Rh2(μ-CO)(μ-
C(4)-C(3)-C(2)
C(2)-C(3)-C(5)
C(4)-C(3)-C(5)
Crystal Data: C19H20F6ORh2Te2, M ϭ 839.4. Orthorhombic, space
group Pna21 (C92v, No. 33), a ϭ 21.1656(7), b ϭ 9.3360(10), c ϭ
3
Ϫ3
˚
˚
11.082(2) A, V ϭ 2197 A Dc (Z ϭ 4) ϭ 2.538 g cm
.
Results and Discussion
Reaction of [(η-C5H5)2Rh2(μ-CO)(μ-η2:η2-C2(CF3)2)], (1),
with dichalcogens gave small amounts of the dicarbonyl
complex [(η-C5H5)2Rh2(μ-CO)2(μ-η1:η1-C2(CF3)2)], 2a, the
formation of which could be suppressed by the passage of
dinitrogen gas through the solution, and the products of
η1:η2-C(CF3)ϭC(CF3)H)(μ2-SEt)] (for
R ϭ Me) and
[(η-C5H5)2Rh2(μ-CO)(μ-η1:η1-C(CF3)ϭC(CF3)H)(μ2-
SCHMeEt)] (for R ϭ Et), both consequent on a Stevens
rearrangement. However, the analogous reactions with di-
alkyltellurides and dialkylselenides gave compositions cor-
responding to complexes 2.
dichalcogen
cleavage,
[(η-C5H5)2Rh2(μ-ER)2(μ-η1:η1-
C2(CF3)2)], (3). Also isolated from these reactions is the
product of dichalogen cleavage and CO insertion,
Scheme 1
Z. Anorg. Allg. Chem. 2008, 675Ϫ681
© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.zaac.wiley-vch.de
679

M. P. Devery, R. S. Dickson, G. D. Fallon, G. A. Koutsantonis, B. W. Skelton, A. H. White
with the ferrocenyl moiety. Thus singlets are seen for both
the unsubstituted Fe(η-C5H5) groups, reflecting the asym-
metry, while the E-(η-C5H4)Fe fragments give more compli-
cated resonances consistent with expectations. In the case
of 3j an alternative isomer, 3jЈ, was isolated which gave mass
spectra identical to 3j but differed in the resonances attri-
buted to the ferrocenyl moiety, perhaps indicative of varia-
tions in orientation of the ferrocenyl substituent.
All the complexes 4 exhibit characteristic ν(CO) stretch-
ing frequencies assigned to the μ-η1:η1-C2(CF3)2C(O) li-
Similarly reaction of 1 with a strained cyclic thio-, seleno-
gand. Complexes 4 lack the symmetry seen in 3 and, in
consequence, two Rh(η-C5H5) resonances are observed in
their H-NMR spectra between 5.0 and 5.5 ppm. This in-
and telluro- ether compounds gave the addition products
(analogous to 2) reversibly in the first instance [18], but
work-up of solutions containing excess cyclochalcoether
gave complexes 5. These complexes can also be prepared by
the reaction of the elements [18] with 1; in the case of el-
emental Se another isomer 6 was isolated, the structure
sharing a similarity with complexes 4.
1
equivalence is also seen in the resonances attributable to the
1
alkyl groups in 4a, cϪf. This is illustrated in the H-NMR
spectrum of 4e where two septets were observed for the
methine proton of the i-Pr group at 2.70 and 2.92 ppm,
respectively. Additionally, the four doublets between 1.1
and 1.6 ppm can be attributed to the i-Pr methyl substitu-
ents. The 125Te NMR spectrum of 4f contains two sets of
overlapping doublets of doublets at Ϫ246 and Ϫ8 ppm,
respectively, each showing couplings to Rh of 97 and
75 Hz, respectively.
Spectroscopic characterization of complexes 3 and 4
In general the 1H-NMR spectra obtained for the complexes
3 were unremarkable with most complexes giving single res-
onances for their cyclopentadienyl ligands attached to Rh.
The thiolates 3a,b give spectra that are consistent with puta-
tive m-symmetry, although both complexes have inequiva-
lent thiolate groups. In 3a the Me group is coupled to the
two equivalent Rh nuclei with a value that is consistent with
that measured for [Rh(CO)2(μ-SMe)2] [24]. The 13C-NMR
spectrum also reflects the inequivalence of the methyl
The 19F NMR spectra of all complexes 4 all contained
two quartets at ca. Ϫ50 and Ϫ55 ppm, respectively, and ex-
5
hibiting long range JFF couplings of ca. 15 Hz.
1) M. P. Devery, Ph.D. thesis ’The Coordination and Subsequent
Rearrangement of Group 16 Donor Ligands to a Dinuclear Rho-
dium Complex’, Monash University, 1997, reports the determina-
tion of the structure of 3h, recording limited crystallographic and
geometrical detail: C20H24F6Rh2Te2, M ϭ 839.4. Monoclinic, space
1
groups while the H-NMR spectrum of 3b clearly shows
that the phenylthiolato substituents are also inequivalent.
This observation is consistent with one of the groups being
directed at the alkyne and the other directed away, sup-
ported, in part, by the X-ray crystal determination of 3h1).
The trifluoromethyl groups were found to be equivalent
with chemical shift consistent with other examples of μ-
η1:η1-C2(CF3)2 complexes [18Ϫ20, 25].
In contrast to the thiolates, the reaction of the diselenides
and ditellurides gave complexes 3 and 4. Complexes 3d, fϪi
are all simple alkyl substituted chalcogenides and display
similar spectra while the complexes 3c, e, j are complicated
by additional resonances associated with the ferrocene moi-
ety.
˚
group P21/n, a ϭ 17.731(4), b ϭ 16.193(3), c ϭ 18.250(3) A, β not
3
Ϫ3
˚
recorded, V ϭ 4872 A . Dc ϭ 2.30 g cm (Z ϭ 8). N ϭ 14297,
No ϭ 6100; R ϭ 0.047, Rw ϭ 0.079; T ca. 295 K. The two molecules
of the asymmetric unit comprise a pair of distinct rotamers ’A’ and
’B’, differing substantively only in respect of the orientations of the
pendant iPr and CF3 groups. As in 4d, one of the Te pendants (that
attached to Te(1)) lies on the side of the Te2Rh2 ring directed away
from the alkene bridge, while the other lies toward; the available
core geometries are summarized below.
Selected bond lengths and angles for 3h
The 1H-NMR spectra of 3d, fϪi are consistent with those
observed for the thiolates. Thus, the two alkyl groups are
stereochemically distinct and the various couplings ob-
served reflect this phenomenon. Further support for this
conjecture was found in the 125Te NMR spectrum of 3i
where two resonances were observed, firstly a doublet at
Ϫ7.1 ppm showing a coupling to Rh of 87 Hz and an
overlapping doublet of doublets at Ϫ115 ppm, with
apparent couplings to the two Rh atoms of 76 Hz. These
RhTe couplings are consistent with those found for
[RhX3(TeMe2)3](X ϭ halide) in the range 66-94; it is of note
that the range of 125Te chemical shifts spans over 4000 ppm
[26]. The diferrocenyl substituted products 3c, e, j have ad-
ditional resonances in their 1H-NMR spectra associated
Atoms
Mol. 1, p arts n ϭ 1,2 Mol. 2, parts n ϭ 1,2 < >
˚
Distances/A
Rh Ϫ Te(1) 2.575(1), 2.562(2)
Rh Ϫ Te(2) 2.556(1), 2.561(2)
2.561(1), 2.579(2)
2.561(2), 2.557(2)
3.439
2.564(8)
·
Te···Te
Rh···Rh
Te(n)-C
Rh-C
3.443
3.584
2.18(1), 2.19(1)
2.08(1), 2.09(1)
1.37(2)
3.441(3)
3.579(7)
2.19(1)
2.09(1)
1.36(2)
2.22(2)
3.574
2.18(2), 2.19(2)
2.08(1), 2.09(2)
1.35(2)
2.22(2) 2.19(2)
Ϫ2.23(2) Ϫ2.25(4)
C-C
Rh Ϫ C(cp) 2.18(3) 2.17(3)
Ϫ2.22(2) Ϫ2.23(2)
·
< >
2.21(2) 2.21(3)
2.22(1) 2.23(2)
Angles (degrees)
Rh-Te-Rh
Te-Rh-Te
Rh-Te(1)-C 108.7(4), 107.9(5)
Rh-Te(2)-C 105.6(5), 104.6(6)
88.5(1), 88.9(1)
84.3(1), 84.5(1)
88.1(1), 88.6(1)
84.3(1), 82.6(1)
105.7(6), 106.3(10)
104.8(5), 108.2(5)
122.0(10), 122.2(8)
88.5(3)
83.9(9)
107.2(13)
106(2)
A view of molecule 1 of 3h
Rh-C-C
121.1(9), 122.8(11)
122.2(8)
680
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© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Z. Anorg. Allg. Chem. 2008, 675Ϫ681

Dichalcogenide Cleavage and Carbonyl Insertion Reactions on a Dirhodium Bond
The diferrocenyl substituted products 4b, g have ad-
ditional resonances in their 1H-NMR spectra associated
with the ferrocenyl moiety. However, in the case of 4g, an-
other isomeric form was isolated but this appears to be dif-
ferent to the positional isomerism associated with 3j, being
characterized by now different Rh(η-C5H5) environments
and different trifluoromethyl environments. The nature of
this isomerism has yet to be determined.
dichalcogens by coordination, undergoing subsequent
cleavage of the dichalcogen bond; in the cases of the Se and
Te derivatives we have been able to isolate products that
involve the insertion of CO into the Rh-fluoroalkyne bond
to give enone ligands. We have also shown that the chalcog-
ens are able to support the Rh···Rh vector while reactions
occur at the Rh atoms, thus shedding some light on the
interactions of dehydrochalcogenization catalysts with
their substrates.
Structure of [(η-C5H5)2Rh2(CO)(μ-TeEt)2(μ-η1:η1-
C2(CF3)2C(O))], (4d)
References
[1] A. J. Bailey, S. Basra, P. J. Dyson, Green Chem. 1999, 31.
[2] S. Rossini, Catal. Today 2003, 77, 467.
[3] S. Eijsbouts, S. W. Mayo, K. Fujita, Appl. Catal. A 2007,
322, 58.
[4] L. Shi, K. C. Tin, N. B. Wong, C. L. Li, Petroleum Science
and Technology 1999, 17, 519.
[5] R. C. Brady, III, R. Pettit, J. Am. Chem. Soc. 1980, 102, 6181.
[6] E. L. Muetterties, Science 1977, 196, 839.
[7] T. Tanase, R. A. Begum, H. Toda, Y. Yamamoto, Organomet-
allics 2001, 20, 968.
The result of the room-temperature single crystal X-ray
structure determination is consistent with the formulation
of 4d, the connectivity of the original ligands no longer be-
ing retained in consequence, unusually, of CO insertion into
the fluorocarbon, as indicated by the formulation above
and depicted in Fig. 1, with pertinent structural param-
eteres presented in Table 1. One formula unit, devoid of
crystallographic symmetry, comprises the asymmetric unit
of the structure, overall a racemate, albeit crystallizing in a
non-centrosymmetric space group. The Rh···Rh distance of
[8] F. Zaera, Chem. Rev. 1995, 95, 2651.
[9] P. Braunstein, J. Rose, Metal Clusters in Chemistry 1999, 2,
616.
˚
3.7618(8) A is much longer than in related adducts defined
[10] R. J. Angelici, Transition Metal Sulphides, NATO ASI Series,
Series 3: High Technology 1998, 60, 89.
[11] P. Braunstein, J. Rose, Catalysis by Di- and Polynuclear Metal
Cluster Complexes 1998, 443.
[12] R. J. Angelici, Acc. Chem. Res. 1988, 21, 387.
[13] D. F. Shriver, H. D. Kaez, R. D. Adams, Eds. The Chemistry
of Metal Cluster Complexes, VCH: New York, 1990.
[14] G. Schmid, Chem. Rev. 1992, 92, 1709.
[15] G. Schmid, Ed., Clusters and Colloids, VCH, Weinheim, 1994.
[16] B. F. G. Johnson, J. Mol. Catal. 1994, 86, 51.
[17] C. E. Anson, N. Sheppard, B. R. Bender, J. R. Norton, J. Am.
Chem. Soc. 1999, 121, 529.
[18] M. P. Devery, R. S. Dickson, B. W. Skelton, A. H. White,
Organometallics 1999, 18, 5292.
[19] M. P. Devery, R. S. Dickson, G. D. Fallon, B. W. Skelton, A.
H. White, J. Organomet. Chem. 1998, 551, 195.
[20] M. P. Devery, R. S. Dickson, J. Chem. Soc., Chem. Comm.
1994, 1721.
[21] D. F. Shriver, M. A. Drezdon, The Manipulation of Air-Sensi-
tive Compounds, Wiley, New York, 1986.
[22] R. S. Dickson, S. H. Johnson, G. N. Pain, Organomet. Synth.
1988, 5, 283.
hitherto in which Rh-Rh bonds are ascribed.
At first sight the molecule has putative m symmetry, only
trivially broken by, primarily, the ethyl pendants of the
bridging tellurium atoms. The skeleton of the bridging hy-
drocarbon ligand might at first sight also appear planar,
but, in fact, is quite distorted, C(3)-C(5) being essentially a
single bond and C(5)-O(5) multiple in character, with
C(1-4) essentially planar (χ2 676); non-defining atom devi-
ations are: Rh(1,2); Te(1,2); C,O(5) Ϫ0.670(8), Ϫ0.35(1);
˚
Ϫ2.250(9), 0.85(1); 0.511(8), 1.488(8) A, the C(2,3,5,)O(5)
´
torsion angle being Ϫ126.2(5)°. The contact O(5)···F(43)
may be instrumental in effecting ligand non-planarity, being
˚
2.752(5) A. The Rh2Te2 array is folded, the RhTe2/Te2Rh
´
interplanar dihedral angle being 28.62(5)°. The differences
in hydrocarbon substituent type at the two rhodium atoms,
despite the asymmetry, appears to have little impact: Rh-
Te distances are similar (range overall: 2.5774(5)-2.5873(5)),
˚
Rh(1)-C(2) 2.095(4), cf. Rh(2)-C(5), 1.991(4) A, and C-Rh-
´
´
Te 82.8(1), 93.0(1)° for Rh(1) and 89.7(1), 83.2(1)° for
Rh(2), there being a noticeable skewing of the array, re-
flected in the C-Te-Rh angles at each tellurium atom.
[23] G. M. Sheldrick, SHELXL 97, ’A Program for Crystal Struc-
ture Refinement’, University of Göttingen, 1997.
[24] E. S. Bolton, R. Havlin, G. R. Knox, J. Organomet. Chem.
1969, 18, 153.
[25] R. S. Dickson, G. S. Evans, G. D. Fallon, Aust. J. Chem. 1985,
38, 273.
Conclusions
We have shown that the dirhodium complex [(η-
C5H5)2Rh2(μ-CO)(μ-η2:η2-C2(CF3)2)] readily adds dialkyl
[26] J. Mason, Multinuclear NMR, Plenum, New York, 1987.
Z. Anorg. Allg. Chem. 2008, 675Ϫ681
© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.zaac.wiley-vch.de
681