A novel route to formaldehyde and thioformaldehyde rhodium complexes

Article abstract of DOI:10.1002/(sici)1099-0682(199811)1998:11<1605::aid-ejic1605>3.0.co;2-h

The acetoxymethyl rhodium compounds [(η⁵-C₅R₅)Rh(CH₂OAc)(L)I] (4, 13-16) which were prepared from the chloromethyl derivatives [η⁵-C₅R₅)Rh(CH₂Cl)(L)I] and sodium acetate in benzene/acetic acid as solvent, reacted with AgPF₆ to give the chelate complexes [(η⁵-C₅R₅)Rh{κ²2-C ₁O-CH₂OC(Me)O}(L)]PF₆ (19-23) in excellent yields. Treatment of these complexes with KOH in methanol led to the elimination of the acetyl group and to the formation of the formaldehyde compounds [(η⁵-C₅R₅)Rh(η²-CH ₂O)(L)] (24-27). The related thioformaldehyde complexes [(η⁵-C₅Me₅)Rh(η₂-CH ₂S)(L)] (46, 47) and [(η⁵-C₅H₅)Rh(η²-CH ₂S)(PMe₃)] (50) were obtained on a similar route. Studies on the reactivity of the formaldehyde derivatives revealed that the Rh-CH₂O bond is rather labile and the CH₂O ligand easily converted to a CO group.

Full text of DOI:10.1002/(sici)1099-0682(199811)1998:11<1605::aid-ejic1605>3.0.co;2-h

FULL PAPER
A Novel Route to Formaldehyde and Thioformaldehyde Rhodium ComplexesȠ
Helmut Werner*a, Margarete Steinmetza, Karl Petersb, and Hans Georg von Schneringb
Institut für Anorganische Chemie der Universität Würzburga,
Am Hubland, D-97074 Würzburg, Germany
Max-Planck-Institut für Festkörperforschungb,
Heisenbergstraße 1, D-70506 Stuttgart, Germany
Received June 9, 1998
Keywords: Rhodium / Carbenoide metal complexes / Formaldehyde complexes / Thioformaldehyde complexes /
Cyclopentadienyl complexes
The
acetoxymethyl
rhodium
compounds
[(η5-
the formaldehyde compounds [(η5-C5R5)Rh(η2-CH2O)(L)]
(24–27). The related thioformaldehyde complexes [(η5-
C5Me5)Rh(η2-CH2S)(L)] (46, 47) and [(η5-C5H5)Rh(η2-
CH2S)(PMe3)] (50) were obtained on a similar route. Studies
on the reactivity of the formaldehyde derivatives revealed
that the Rh–CH2O bond is rather labile and the CH2O ligand
easily converted to a CO group.
C5R5)Rh(CH2OAc)(L)I] (4, 13–16) which were prepared from
the chloromethyl derivatives [(η5-C5R5)Rh(CH2Cl)(L)I] and
sodium acetate in benzene/acetic acid as solvent, reacted
with AgPF6 to give the chelate complexes [(η5-C5R5)Rh{κ2-
C,O-CH2OC(Me)O}(L)]PF6 (19–23) in excellent yields.
Treatment of these complexes with KOH in methanol led to
the elimination of the acetyl group and to the formation of
In a series of papers we have recently shown[1] that cobalt
and rhodium half-sandwich type complexes, which contain
MI(CH2I) as a molecular unit, can be transformed to the
corresponding thio-, seleno-, and telluroformaldehyde
metal derivatives upon treatment with SHϪ, SeHϪ, and
TeHϪ, respectively (see Scheme 1). Due to the lone electron
pairs at the chalcogen atom of the CH2E ligand, these com-
pounds behave as Lewis bases and react with in situ gener-
ated 16-electron fragments such as [W(CO)5] or [(η5-
C5H5)Mn(CO)2] to give dinuclear hetero-metallic com-
plexes with the aldehyde CH2E in a bridging position.[1d][2]
First attempts to complete the series of compounds [(η5-
C5R5)M(η2-CH2E)(L)] by those with E ϭ O failed. The re-
action of the respective precursor [(η5-C5R5)M(L)(LЈ)] with
monomeric formaldehyde was rather slow and in most cases
led to a mixture of products among which the carbonyl
complexes [(η5-C5R5)M(CO)(L)] were the dominating spe-
cies. Therefore, we had to develop a different synthetic
route. The present paper describes that for M ϭ Rh the
key to success was the preparation of metalated acetic acid
derivatives [Rh]CH2OC(O)CH3 as intermediates which
could be converted in two steps to the coordinated formal-
dehyde ligand. Some related results to this work were al-
ready reported.[3]
Results
Preparation of RhCH2OAc Precursors
The carbenoide rhodium complex 1, which can easily be
prepared from [C5Me5Rh(CO)2] and CH2I2,[4] reacts quite
smoothly in polar solvents with sodium acetate. While in
acetone a mixture of products is formed, the reaction of 1
with excess NaOAc in methanol leads to the meth-
oxymethyl compound 2 in good yield. In contrast, the start-
ing material 1 and NaOAc react in ethanol to give two
products 3 and 4 (see Scheme 2), which could be separated
by chromatographic techniques. Although the desired ace-
toxy derivative 4 is the dominating species provided that an
excess of sodium acetate is used, the separation of the two
compounds on Al2O3 results in the partial conversion of 4
Scheme 2. [Ac ϭ CH3CO]
Scheme 1
Eur. J. Inorg. Chem. 1998, 1605Ϫ1617
WILEY-VCH Verlag GmbH, D-69451 Weinheim, 1998
1434Ϫ1948/98/1111Ϫ1605 $ 17.50ϩ.50/0
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H. Werner, M. Steinmetz, K. Peters, H. G. von Schnering
FULL PAPER
Scheme 3. [Ac ϭ CH3CO]
to the dinuclear complex [{(η5-C5Me5)Rh(µ-CO)}2]. There- Figure 1. Conformations of compounds [(η5-C5R5)Rh(CH2X)(L)I]
(X ϭ Cl, OAc) viewed along the RhϪC axis. Due to the formally
fore, the isolated yield is rather low.
octahedral geometry the bond angle PϪRhϪI is assumed to be 90°
(see also ref.[8]
)
The method of choice for the preparation of 4 is the reac-
tion of 7 with excess NaOAc in a mixture of benzene and
glacial acetic acid as the solvent. Under these conditions,
not only 4 but also the half-sandwich type RhϪCH2OAc
complexes 13Ϫ16 (Scheme 3) have been obtained in
80Ϫ85% yield. The synthesis of the formerly unknown
chloromethyl rhodium(III) precursors 7 and 8 was achieved
by oxidative addition (followed by elimination of CO or
C2H4) of CH2ClI to [(η5-C5Me5)Rh(CO){P(OMe)3}] and
[(η5-C5H5)Rh(C2H4){P(OMe)3}], respectively. We note that using different nucleophiles failed.[9] Whereas treatment of
the rate of formation of 15 from 11 is significantly higher 4 with NaOMe in methanol/benzene or with nBuLi in ben-
than from [(η5-C5Me5)Rh(CH2I)(PMe3)I][4] which can be zene led mainly to decomposition (and to the formation of
understood by the HSAB concept: Substitution of the hard small amounts of [{(η5-C5Me5)Rh(µ-CO)}2]), the reaction
chloride by the hard nucleophile OAcϪ is favoured com- of 15 with NaOMe in methanol or with NaOH in water/
pared to the displacement of the soft iodide by acetate.[5]
benzene in the presence of [PhCH2NEt3]Cl (TEBA) as
The acetoxymethyl derivatives 4 and 13Ϫ16 are yellow to phase-transfer catalyst gave mainly the mononuclear com-
red-brown microcrystalline solids, which are air-stable and pound [(η5-C5Me5)Rh(CO)(PMe3)].[10] Although the 1H-
soluble in common organic solvents. The most typical fea- NMR spectrum of the reaction mixture formed from 15
ture of the 1H-NMR spectra of 4 and 13Ϫ16 is the appear- and NaOMe in CD3OD showed that besides the carbonyl
ance of two distinct signals for the methylene protons of complex [(η5-C5Me5)Rh(CO)(PMe3)] the corresponding
the CH2OAc group which due to Rh-H, H-H, and in some formaldehyde compound 26 (see Scheme 5) is probably
cases P-H coupling are split into doublets of doublets or formed, the attempts to separate the two C5Me5Rh species
appear as doublets of doublets of doublets. Since the size by chromatographic techniques failed. One noteworthy re-
3
of J(PH), which depends on the mutual orientation of the sult is that from the mixture of products obtained upon
phosphorus and the hydrogen atoms of the PRhCH2 unit,[6] treatment of the trimethylphosphite complex 14 with two
differs considerably (e.g. between 0 Hz and 8.8 Hz for 15), equiv of nBuLi in benzene/hexane the half-sandwich type
we assume that the rotation around the RhϪCH2O axis is rhodium(III) derivatives 17 and 18 (Scheme 4) could be iso-
1
partially hindered and the conformations A or B (Figure 1) lated in low yield. The H NMR data as well as the mass
are preferred. A similar observation has already been made spectra and (in the case of 17) the elemental analysis re-
for compounds such as 12 and [(η5-C5H5)Rh(CH2X)- vealed that both in 17 and 18 a RhϪC6H5 bond is present,
(PMe3)X] (X ϭ Br, I)[7] as well as for related cyclopen- the phenyl group originating either from benzene or from
tadienyliron derivatives [(η5-C5H5)Fe(CH2R)(CO)(PRЈ3)] in situ generated LiPh, respectively.
(R ϭ Ph, SiMe3).[8]
The methodology for the successful preparation of the
formaldehyde rhodium complexes 24Ϫ27 is outlined in
Scheme 5. Instead of an attack of a nucleophile to the car-
bon atom of the acetoxy unit of 4 and 13Ϫ16 the first step
Conversion of RhCH2OAc to Rh(η2-CH2O) Complexes
Attempts to convert the acetoxymethyl compounds 4 and involves the cleavage of the RhϪI linkage by AgPF6. This
13Ϫ16 to the corresponding formaldehyde complexes by is followed by the formation of a five-membered chelate
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Eur. J. Inorg. Chem. 1998, 1605Ϫ1617

A Novel Route to Formaldehyde and Thioformaldehyde Rhodium Complexes
FULL PAPER
˚
Scheme 4. [Ac ϭ CH3CO]
with the rhodium center. The distance C2ϪO1 [1.240(8) A]
indicates significant double bond character which is in
agreement with the bonding pattern shown for 19Ϫ23 in
Scheme 5. The corresponding CϭO bond length in the va-
nadium complex [(η5-C5H5)2V{κ2-C,O-CH2OC(Me)O}]ϩ is
1.236(4) A[12] and thus almost identical to that in 22. Com-
pared with C2ϪO1, the distance C2ϪO3 [1.307(8) A] is
˚
˚
considerably longer and quite similar to the CϪO(W) dis-
tance found in [(η5-C5H5)W(CO)3(OAc)].[13] The RhϪC4
˚
bond length [2.067(6) A] is somewhat shorter than in re-
lated cationic cyclopentadienylrhodium compounds such as
[14]
[(η5-C5H5)Rh(CH2NC5H5)(PMe3)I]ϩ
and [(η5-C5H5)-
RhCH3(CO)(PPh2R)]ϩ [R ϭ NHCH(Me)Ph][15] which
could be due to the electronic effect caused by the OAc
group. The RhϪC4ϪO3 bond angle is 109.7(4)° which is
consistent with the sp3 hybridization of the CH2 carbon
atom. The distances between rhodium and the carbon
atoms of the C5Me5 ring are in the usual range for com-
plexes containing the C5Me5Rh(PMe3) unit.[16] However, as
has previously been observed for those half-sandwich type
compounds with π-donating ligand,[7][17] the metalϪcarbon
bond lengths [RhϪC5 and RhϪC6] trans to this ligand are
shorter than the other RhϪC(ring) distances.
ring. Since the coordination of the carbonyl oxygen atom
to the metal increases the δϩ charge at the CϭO carbon
atom, a subsequent nucleophilic attack at this carbon is pre-
ferred. Finally, the products 24Ϫ27 are obtained in moder-
ate yield. It should be emphasized that even treatment of
the highly reactive bis(trimethylphosphane) compounds
[(η5-C5H5)Rh(PMe3)2] and [(η5-C5Me5)Rh(PMe3)2][11] with
formaldehyde does not lead to 26 and 27 but instead gives
the carbonyl derivatives [(η5-C5H5)Rh(CO)(PMe3)] and
[(η5-C5Me5)Rh(CO)(PMe3)].
Figure 2. Molecular structure of 22[a] (thermal elipsoids with 50%
probability)
Scheme 5
The chelate complexes 19Ϫ23 are yellow to orange-yel-
low air-stable solids which in nitromethane display the con-
ductivity expected for 1:1 electrolytes. The spectroscopic
data of 19Ϫ23 and of the non-ionic precursors 4 and 13Ϫ16
differ insofar, as in the 13C NMR spectra of 19Ϫ23 the
signal of the CϭO carbon atom is shifted significantly
(16Ϫ20 ppm) to lower field due to the interaction of the
acetyl moiety with the metal. In the IR spectra of the che-
late compounds the CϭO stretching frequency is also re-
duced and appears at 1600Ϫ1610 cmϪ1 compared with
1700Ϫ1720 cmϪ1 for 4 and 13Ϫ16, respectively. For the di-
[a]
˚
Selected bond lengths [A] and angles [°]: RhϪP1 2.300(2),
RhϪO1 2.112(4), RhϪC4 2.067(6), RhϪC5 2.170(6), RhϪC6
2.179(6), RhϪC7 2.254(6), RhϪC8 2.230(7), RhϪC9 2.198(6),
O1ϪC2 1.240(8), C2ϪO3 1.307(8), C2ϪC20 1.501(9), O3ϪC4
1.471(7); P1ϪRhϪO1 91.3(1), P1ϪRhϪC4 87.7(2), O1ϪRhϪC4
77.9(2),
RhϪO1ϪC2
113.9(4),
O1ϪC2ϪO3
122.2(6),
O1ϪC2ϪC20 122.6(6), O3ϪC2ϪC20 115.2(6), C2ϪO3ϪC4
116.0(5), RhϪC4ϪO3 109.7(4).
The second step of the synthesis of compounds 24Ϫ27
cyclopentadienylvanadium complexes [(η5-C5H5)2V{η1- (see Scheme 5) proved to be difficult. Treatment of the ace-
CH2OC(O)R}Cl] and [(η5-C5H5)2V{κ2-C,O-CH2OC(R)- toxymethyl complexes 20Ϫ23 with NaOMe or KOH in
O}]BPh4 an almost identical trend has been observed.[12]
methanol at room temperature gave in each case a mixture
The result of the X-ray crystal structure analysis of 22 is of products with the carbonyl and the formaldehyde com-
shown in Figure 2. The acetoxymethyl unit acts as a biden- pounds [(η5-C5R5)Rh(CO)(L)] and [(η5-C5R5)Rh(η2-
tate ligand and forms a nearly planar five-membered ring CH2O)(L)] as the dominating species. Attempts to separate
Eur. J. Inorg. Chem. 1998, 1605Ϫ1617
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H. Werner, M. Steinmetz, K. Peters, H. G. von Schnering
FULL PAPER
these mixtures by chromatographic techniques led mainly Scheme 6
to the isolation of the RhϪCO complexes. However, the
rate of the decomposition of the formaldehyde derivatives
to [(η5-C5R5)Rh(CO)(L)] could be considerably reduced if
the reaction of 20Ϫ23 with base was carried out at low
temperature. After the reaction mixture was worked up at
0°C, oily products were obtained which could partly be
converted to yellow-brown microcrystalline solids. Since the
formaldehyde compounds 24Ϫ27 are not only labile (and
air-sensitive) but also readily soluble in pentane, the yield
of the isolated solids did not exceed 30%.
Even more labile than the trimethylphosphite and tri-
methylphosphane complexes 24Ϫ27 is the corresponding
carbonyl derivative [(η5-C5Me5)Rh(η2-CH2O)(CO)]. Ad-
dition of excess NaOMe to a solution of 19 in methanol at
Ϫ78°C led initially to the formation of a clear yellow solu-
tion which rapidly turned blue if the same work-up pro-
cedure was used as applied for 24Ϫ27. The isolated product
consisted of both [(η5-C5Me5)Rh(CO)2] and the dinuclear
compound [{(η5-C5Me5)Rh(µ-CO)}2]. However, the 1H-
NMR spectrum of the reaction mixture in CD3OD at
Ϫ40°C displayed two doublets of doublets at δ 5.67
[J(RhH) ϭ 4.4, J(HH) ϭ 6.1 Hz] and 5.46 [J(RhH) ϭ 0.6,
J(HH) ϭ 6.1 Hz] and one doublet at δ 1.66 [J(RhH) ϭ 0.4
Hz] which can be assigned to the CH2 and C5Me5 protons
of [(η5-C5Me5)Rh(η2-CH2O)(CO)], respectively.
experiments aimed to find out whether during the de-
composition besides the carbonyl derivatives other com-
pounds are formed too. If the course of the thermal de-
composition of 24, 26, and 27 in C6D6 is studied in an
NMR tube at room temperature, the complexes [(η5-
C5R5)Rh(CO)(L)] indeed are the most dominating species
among the observed products. After completion of the reac-
tion the spectroscopically determined yield of the carbonyl
compounds is 80Ϫ90%. Hydrido complexes such as [(η5-
C5Me5)RhH2(PMe3)][21] could not be detected. The most
surprising discovery was that in contrast to the thermolysis
of 24 which gave almost quantitatively [(η5-
C5Me5)Rh(CO){P(OMe)3}],[22] the corresponding reaction
of 25 led to a mixture of 31 and 32 (Scheme 7) in the ratio
of ca. 70:30 under the same conditions (benzene, 25°C). If
a somewhat higher concentration of 25 is used, the relative
amount of the dinuclear complex increases and, after frac-
tional crystallization, the isolated yield of 31 (which is a
green moderately air-sensitive solid) is about 40%.
With regard to the spectroscopic data of the isolated for-
maldehyde complexes, we note that at least in the case of
25, 26, and 27 for the methylene protons of the coordinated
CH2O ligand two distinct signals (both doublets of doublets
2
of doublets) have been observed. The J(HH) coupling of
18.2Ϫ21.5 Hz lies between that of free formaldehyde (42.2
Hz) and ethylenoxide (5.5 Hz)[18] and indicates some double
bond character for the CϪO bond. The H-H coupling con-
stant of 25Ϫ27 is quite similar to that of the cationic rhe-
nium compound [(η5-C5H5)Re(η2-CH2O)(NO)(PPh3)]ϩ
(16.6 Hz)[19] for which according to the structural data also
a partial CϪO double bond character has been postulated.
We note that a three-membered MCO ring as shown in
Scheme 6 dominates the structural chemistry of formal-
dehyde complexes containing the Zr(C5H5)2 unit which is
probably due to the higher oxophilicity of electron-poor
transition-metal centres.[12][20]
Scheme 7
To find out whether complexes that are structurally re-
lated to 19Ϫ23 are also suitable starting materials for the
generation of formaldehyde rhodium derivatives, com-
pounds 28 and 29 (Scheme 6) have been prepared. Both
were obtained via the same route as 16 and 23 and charac-
terized by elemental analysis and spectroscopic means.
However, treatment of 29 with various bases led to a mix-
ture of products among which 27 could not be exactly
identified.
The structural proposal for 31 is mainly supported by the
mass spectrum and the NMR spectroscopic data. In the
mass spectrum peaks for Mϩ, Mϩ Ϫ P(OMe)3, and M/2ϩ
Reactions of Rh(η2-CH2O) Complexes
are observed, which is in agreement with the presence of a
1
The striking lability of the formaldehyde rhodium com- dinuclear framework. The H-NMR spectrum displays two
plexes [(η5-C5R5)Rh(η2-CH2O)(L)] initiated a series of signals for the protons of the C5H5 and P(OMe)3 ligands,
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Eur. J. Inorg. Chem. 1998, 1605Ϫ1617

A Novel Route to Formaldehyde and Thioformaldehyde Rhodium Complexes
FULL PAPER
while the 31P-NMR spectrum displays only a single reso- Scheme 8
nance, its splitting being consistent with a spectrum of an
AAЈXXЈ type (A,AЈ ϭ 31P; X, XЈ ϭ 103Rh). Since com-
pound 31 is formally an analogue of the well-known car-
bonyl complex [{(η5-C5Me5)Rh(µ-CO)}2] (the structural
data of which indicate the presence of a metalϪmetal
double bond),[23] we tentatively assign a similar bonding
pattern also to 31. The spectroscopic data are of course
not conclusive as to the cis or trans disposition of the two
cyclopentadienyl (and equally the two phosphite) ligands.
The question of why compound 25 but not the related
complexes 24, 26, and 27 decomposes by loss of formal-
dehyde and formation of a dinuclear product can not be
The formaldehyde complexes 26 and 27 react with
CF3SO3H in a less straightforward manner and afford a
mixture of products. Among those the cations [(η5-
answered definitively. It should be noted, however, that only
in the mass spectra of 24, 26, and 27 the peak of the mole-
cular ion Mϩ appears, while the corresponding peak (m/z ϭ
322) is missing in the mass spectrum of 25. On the other
hand, only in the latter the ion CH2Oϩ is observed with
relatively high intensity. A plausible explanation of these
results is that due to the less pronounced donor character
of C5H5 compared to C5Me5 and of P(OMe)3 compared to
PMe3, the metal-to-formaldehyde bond of compound 25 is
the weaker and can be cleaved more easily than in the
C5Me5Rh and Rh(PMe3) counterparts. The loss of formal-
dehyde from 25 would generate the 16-electron species [(η5-
C5H5)Rh{P(OMe)3}] which dimerizes preferentially and
does not react with CH2O or benzene. The carbonyl com-
plexes [(η5-C5R5)Rh(CO)(L)] as the preferred products of
the thermal decomposition of 24, 26, and 27 (and in part
also of 25) are probably formed via the formyl(hydrido)me-
tal intermediates [(η5-C5R5)RhH(CHO)(L)] which elimi-
nate H2 to give the final products. There is ample evidence
for this pathway, particular due to the work by Thorn[24]
and Roper et al.[25]
1
C5R5)RhH(CO)(PMe3)]ϩ could be identified by H-NMR
spectroscopy.[10][27] Treatment of 26 and 27 with CH2I2
1
leads to the fast displacement of CH2O (detected by H
NMR) and to the formation of [(η5-C5Me5)Rh(CH2I)(P-
Me3)I][4] and [(η5-C5H5)Rh(CH2I)(PMe3)I],[7] respectively.
Compounds 26 and 27 behave thus analogously to the car-
bonyl and ethene derivatives [(η5-C5Me5)Rh(CO)(PMe3)]
and [(η5-C5H5)Rh(C2H4)(PMe3)]. The noteworthy differ-
ence is, however, that the reactions of 26 and 27 with CH2I2
proceed much faster than those of the corresponding car-
bonyl and ethene complexes which is probably due to the
weaker RhϪCH2O compared to the RhϪCO and
RhϪC2H4 bond.
Thioacetate؊ and Thioformaldehyde؊Rhodium Complexes
The methodology used for the preparation of [(η5-
C5R5)Rh(η2-CH2O)(L)] (24Ϫ27) could also be applied for
The reactions of 24, 26, and 27 with methyltriflate follow the synthesis of the corresponding thioformaldehyde com-
an unexpected course. In contrast to several other formal- plexes [(η5-C5R5)Rh(η2-CH2S)(L)]. The investigations,
dehyde metal complexes which react with HX or RX by which were carried out to obtain the respective precursors,
attack of the electrophile to the CH2O oxygen are summarized in Schemes 9 and 10. Reaction of the start-
atom,[12][25b][26] on treatment of 24, 26, or 27 with ing material 36 with excess CH3COSK in benzene/
CF3SO3CH3 no RhCH2OCH3 species could be detected. thioacetic acid led not only to cleavage of the CH2ϪI but
Instead the triflates of the cationic complexes 33Ϫ35 were also to that of the RhϪI and RhϪC bonds and gave the
formed. While the isolated yield of 33 and 34 was high, that bis(thioacetato)rhodium(III) compound 37 in nearly 80%
of 35 was rather low which could be due to the lability of yield. In contrast, treatment of 36 with one equiv of
the RhϪCO bond in the rhodium(III) species. The PF6 salts CH3COSK in benzene/ethanol afforded a mixture of 38 and
of the cations [(η5-C5R5)Rh(CH3)(CO)(PMe3)]ϩ (R ϭ H, the known ethoxymethyl complex 39,[3] which could be
Me) were previously prepared in our laboratory either from separated by fractional crystallization from pentane. The
the acyl derivative [(η5-C5Me5)Rh{C(O)CH3}(PMe3)I] and isolated yield of 38 was about 60%. If the separation of
[10]
AgPF6
or by salt metathesis from [(η5-C5H5)Rh- 38 and 39 was attempted by column chromatography using
(CH3)(CO)(PMe3)]I and NH4PF6[27]. We assume that com- deactivated Al2O3, loss of the CH2 fragment of the CH2SAc
pounds 33Ϫ35 are formed via the carbonyl complexes [(η5- ligand of 38 occurred and the half-sandwich rhodium(III)
C5R5)Rh(CO)(L)] and that the electrophile CF3SO3CH3 compound 40 was obtained. Both 37 and 38 as well as 40
strongly facilitates the conversion of 24, 26, and 27 to were characterized by elemental analyses, mass spectra and
[(η5-C5R5)RhH(CHO)(L)] and subsequently to [(η5- IR and NMR spectroscopic techniques.
C5R5)Rh(CO)(L)]. This mechanistic proposal is supported
The preparation of the pentamethylcyclopentadienyl
by the observation that upon addition of methyltriflate to complexes 43 and 44 from the RhCH2I precursors 41 and
solutions of the starting material a rapid evolution of gas 42 and CH3COSK in benzene/ethanol proceeded in a clear
(H2) is observed.
manner and gave the expected products almost quantita-
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H. Werner, M. Steinmetz, K. Peters, H. G. von Schnering
FULL PAPER
Scheme 9. [Ac ϭ CH3CO]
ceeded then analogously as described for the Rh(η2-
CH2O) counterparts.
Scheme 11. [Ac ϭ CH3CO]
tively. In this case, no byproducts such as [(η5-
C5Me5)Rh(CH2OEt)(L)I] [L ϭ P(OMe)3, PMe3] were ob-
served. The reaction of 42 with an excess of potassium
thioacetate led both to the cleavage of the CH2ϪI and the
RhϪI bond and produced the thioacetatorhodium(III) de-
rivative 45. The same compound was obtained from 44 and
an equimolar amount of CH3COSK. The 1H-NMR spectra
of complexes 38, 43, and 44, each containing a RhCH2SAc
unit, display two distinct signals for the diastereotopic CH2
protons which are well separated (by 0.2 to 0.7 ppm) and
due to Rh-H, P-H, and H-H coupling appear as doublets
of doublets of doublets.
However, in contrast to 24Ϫ27 the Rh(η2-CH2S) com-
plexes 46 and 47 can also be prepared directly from 43 and
44 upon treatment with nBuLi in benzene/hexane. After the
reaction mixture was worked up by column chromatogra-
phy using Al2O3, the isolated yield of 46 and 47 was 75%.
The (η5-C5H5)Rh derivative 50, which had previously been
prepared from 36 and two molar equivalents of Na-
SH,[1a][1d] was obtained on the same route. In this context
it should be reminded that treatment of 14 (a related species
to 38 with a RhCH2OAc linkage) did not yield the corre-
sponding formaldehyde complex 25, probably due to the
lability of the RhϪCH2O bond toward the organolithium
reagent. We note that the 1 H-, 13C-, and 31P-NMR spectra
of 46 and 47 are quite similar to those of the cyclopen-
tadienyl complexes [(η5-C5H5)Rh(η2-CH2E)(L)] (E ϭ S, Se,
Te; L ϭ PMe3, PMe2Ph, PiPr3)[1d] and thus deserve no
further comment.
Scheme 10. [Ac ϭ CH3CO]
Discussion
The present investigation has shown that carbenoide rho-
dium compounds containing Rh(CH2X)I as a molecular
fragment are not only useful starting materials for the syn-
thesis of thio-, seleno-, and telluroformaldehyde com-
plexes[1] but also open up a preparative route to corre-
The thioformaldehyde complexes 46 and 47 can be pre- sponding formaldehyde metal derivatives. Although several
pared in two different ways (see Scheme 11) using either the examples are known which prove that compounds of the
neutral derivatives 43 and 44 or the cationic compounds 48 general composition [M(η2-CH2O)Ln] can be obtained
and 49 as starting materials. The latter were prepared simi- from an appropriate precursor and free formal-
lar to the above mentioned chelate complexes 19Ϫ23 from dehyde,[12][25][28] this method of synthesis failed for com-
43 or 44 and AgPF6 in acetone. The conversion of 48 and plexes such as [(η5-C5R5)Rh(η2-CH2O)(L)]. The main rea-
49 to the thioformaldehyde compounds 46 and 47 pro- son for this is the lability of the RhϪCH2O bond which is
1610
Eur. J. Inorg. Chem. 1998, 1605Ϫ1617

A Novel Route to Formaldehyde and Thioformaldehyde Rhodium Complexes
FULL PAPER
3; yield 68 mg (60%). Subsequently with benzene, first a deep blue
fraction containing [( η5-C5Me5Rh)2(µ-CO)2] and then a yellow
fraction was eluted. The latter was brought to dryness in vacuo,
the residue was washed with pentane (0°C) and dried. A yellow
solid of 4 was obtained; yield 19 mg (16%). Ϫ 3: m. p. 96°C (dec.).
Ϫ IR (C6H6): ν˜ ϭ 2010 cmϪ1 [ν(CO)]. Ϫ 1H NMR (200 MHz,
CDCl3): δ ϭ 5.26 [dd, J(RhH) ϭ 2.0, J(HH) ϭ 3.7 Hz, 1 H, one
H of CH2OEt], 5.06 [dd, J(RhH) ϭ 5.0, J(HH) ϭ 3.7 Hz, 1 H, one
H of CH2OEt], 3.44, 3.22, 1.20 [ABX3 spin system, J(HAHX) ϭ
7.2, J(HBHX) ϭ Ϫ7.2, J(HAHB) ϭ 9.5 Hz, 5 H, OCHAHBC(HX)3],
illustrated by our studies concerned to the reactivity of the
isolated compounds 24Ϫ27. The preferred pathway of de-
composition seems to be the conversion of [Rh](CH2O) to
[Rh](CO) and H2 ([Rh] ϭ [(η5-C5R5)Rh(L)]) which is note-
worthy insofar as the reverse reaction, i.e. the formation of
[M](CH2O) from [M](CO) and hydrogen, is described as an
important step in the metal-assisted hydrogenation of car-
bon monoxide.[29] Presently the state of the art is that elec-
tron-poor transition metal centers are more suitable to sta-
bilize the MϪCH2O bond than electron-rich counterparts 1.96 [d, J(RhH) ϭ 0.5 Hz, 15 H, C5Me5]. Ϫ MS (70 eV); m/z (%) ϭ
452 (10) [Mϩ], 393 (9) [Mϩ Ϫ CH2OEt], 365 (100) [C5Me5RhIϩ],
266 (3) [C5Me5Rh(CO)ϩ], 238 (14) [C5Me5Rhϩ]. Ϫ C14H22IO2Rh
(452.1): calcd. C 37.19, H 4.90; found C 37.45, H 5.03.
which is probably due to the well-known oxophilicity of do-
d4 systems.[30] Electron-rich transition metal centers prefer
to coordinate thio- and selenoformaldehyde instead of
CH2O, which has first been shown by Roper et al.[31] and
has also been confirmed by this work as well as by previous
studies from our laboratory.[1]
3. Preparation of [ ( η5-C5Me5) Rh( CH2OAc) ( CO) I] (4): A solu-
tion of 152.3 mg (0.34 mmol) of 10 in 2 ml of benzene was treated
with a solution of 258 mg (3.16 mmol) of CH3CO2Na in 2 ml of
acetic acid (100%) and stirred for 3 h at 50°C. After cooling to
room temp., the solvent was removed, the oily residue was extracted
with 15 ml of benzene and the extract was brought to dryness in
vacuo. A yellow solid was obtained which was washed with small
portions of pentane (0°C) and dried; yield 103 mg (65%); m. p.
116°C (dec.). Ϫ IR (KBr): ν˜ ϭ 2020 cmϪ1 [ν(CO)], 1715 cmϪ1
[ν(CϭO)]. Ϫ 1H NMR (200 MHz, C6D6): δ ϭ 6.20 [dd, J(RhH) ϭ
J(HH) ϭ 2.2 Hz, 1 H, one H of CH2OAc], 4.93 [dd, J(RhH) ϭ
4.4, J(HH) ϭ 2.2 Hz, 1 H, one H of CH2OAc], 1.70 (s, 3 H, OCH3),
1.53 [d, J(RhH) ϭ 0.5 Hz, 15 H, C5Me5]. Ϫ 13C NMR (22.5 MHz,
CDCl3): δ ϭ 188.7 [d, J(RhC) ϭ 78.0 Hz, Rh(CO)], 170.3 [s,
C(O)CH3], 104.5 [d, J(RhC) ϭ 4.4 Hz, C5Me5], 55.6 [d, J(RhC) ϭ
22.8 Hz, RhCH2], 21.3 [s, C(O)CH3], 10.1 [br. s, C5(CH3)5]. Ϫ
We acknowledge the support for this work by the Deutsche For-
schungsgemeinschaft and the Fonds der Chemischen Industrie. More-
over, we are also grateful to Mrs. R. Schedl and Mr. C. P. Kneis for
elemental analyses and DTA measurements as well as to Mrs. M.
L. Schäfer and Dr. W. Buchner for recording the NMR spectra.
Experimental Section
All operations were carried out in an inert gas atmosphere with
the Schlenk technique. The starting materials 1,[4] 5,[22] 6,[32]
10Ϫ12,[4][7] 36,[32] and 41, 42[4] were prepared as described in the
literature. CH3COSK (KSAc) was prepared as a white microcrys-
talline solid from equimolar amounts of KOH and thioacetic acid
in ethanol and used without further purification. Ϫ MS: Varian
MAT CH7. Ϫ IR: Perkin-Elmer 397. Ϫ NMR: Varian EM 360 L,
Bruker WH 90, AC 200, and WM 400. Ϫ Melting points: DTA.
Ϫ Conductivity measurements (in CH3NO2) with conductometer
C
14H20IO3Rh (465.1): calcd. C 36.06, H 4.32, Rh 22.09; found C
36.01, H 4.24, Rh 21.80.
4. Preparation of [ ( η5-C5Me5) Rh( CH2Cl) {P( OMe) 3}I] (7): A
solution of 236.1 mg (0.61 mmol) of 5 in 8 ml of ether was treated
under continuous stirring dropwise with 80 µl (1.10 mmol) of
CH2ClI. Evolution of gas (CO) was observed. The solution was
stirred for 2 h at room temp. and then concentrated to ca. 2 ml in
vacuo. After pentane (ca. 5 ml) was added, the solution was stored
for 12 h at Ϫ78°C. Orange-red crystals precipitated which were
filtered, washed with small quantities of pentane (Ϫ20°C) and
dried; yield 203 mg (62%); m. p. 106°C (dec.). Ϫ 1H NMR (200
MHz, C6D6): δ ϭ 5.17 [ddd, J(RhH) ϭ 8.0, J(PH) ϭ 1.9, J(HH) ϭ
6.0 Hz, 1 H, one H of CH2OAc], 4.49 [ddd, J(RhH) ϭ 1.6, J(PH) ϭ
4.4, J(HH) ϭ 6.0 Hz, 1 H, one H of CH2OAc], 3.64 [d, J(PH) ϭ
11.5 Hz, 9 H, P(OMe)3], 1.79 [dd, J(RhH) ϭ 0.3, J(PH) ϭ 4.3 Hz,
15 H, C5Me5]. Ϫ 13C NMR (22.5 MHz, C6D6): δ ϭ 101.5 [dd,
J(RhC) ϭ J(PC) ϭ 4.4 Hz, C5Me5], 54.2 [d, J(PC) ϭ 6.6 Hz,
P(OMe)3], 35.5 [dd, J(RhC) ϭ 30.2, J(PC) ϭ 19.1 Hz, RhCH2], 9.6
[d, J(RhC) ϭ 2.2 Hz, C5(CH3)5]. Ϫ 31P NMR (36.2 MHz, C6D6):
δ ϭ 133.1 [d, J(RhP) ϭ 253.1 Hz]. Ϫ MS (70 eV); m/z (%) ϭ 538
(2) [Mϩ], 489 (66) [Mϩ Ϫ CH2Cl], 365 (100) [C5Me5RhIϩ], 362 (2)
[C5Me5RhP(OMe)3ϩ], 238 (8) [C5Me5Rhϩ]. Ϫ C14H26ClIO3PRh
(538.6): calcd. C 31.22, H 4.87; found C 31.21, H 4.92.
Schott CG 851; Λ in cm2ΩϪ1molϪ1
.
1. Preparation of [ ( η5-C5Me5) Rh( CH2OMe) ( CO) I] (2): A sus-
pension of 85.1 mg (0.16 mmol) of 1 in 5 ml of methanol was
treated with 13.5 mg (0.25 mmol) of CH3CO2Na and stirred for 3
h at room temp. The solvent was removed and the residue was
extracted with 10 ml of ether. The extract was brought to dryness
in vacuo and the residue was dissolved in 1 ml of pentane. After
the solution was stored for 12 h at Ϫ78°C, a red-brown microcrys-
talline solid precipitated which was filtered, washed with small por-
tions of pentane (Ϫ20°C) and dried; yield 45 mg (64%); m. p. 77°C
(dec.). Ϫ IR (C6H6): ν˜ ϭ 2007 cmϪ1 [ν(CO)]. Ϫ 1H NMR (200
MHz, C6D6): δ ϭ 5.30 [dd, J(RhH) ϭ 2.0, J(HH) ϭ 3.8 Hz, 1 H,
one H of CH2OMe], 5.15 [dd, J(RhH) ϭ 5.1, J(HH) ϭ 3.8 Hz, 1
H, one H of CH2OMe], 3.03 (s, 3 H, OCH3), 1.68 [d, J(RhH) ϭ
0.5 Hz, 15 H, C5Me5]. MS (70 eV); m/z (%) ϭ 438 (10) [Mϩ], 393
(10) [Mϩ
Ϫ
CH2OMe], 365 (100) [C5Me5RhIϩ], 266 (2)
[C5Me5Rh(CO)ϩ], 238 (10) [C5Me5Rhϩ]. Ϫ C13H20IO2Rh (438.1):
calcd. C 35.64, H 4.60; found C 34.97, H 4.88.
2. Reaction of 1 with CH3CO2Na in Ethanol: A solution of 135.3
5. Preparation of [ ( η5-C5H5)Rh(CH2Cl){P(OMe)3}I] (8) and
mg (0.25 mmol) of 1 in 5 ml of ethanol was treated with 20.9 mg [ ( η5-C5H5) Rh{P( OMe) 3}I2] (9): A solution of 219.5 mg (0.69
(0.26 mmol) of CH3CO2Na and stirred for 15 h at room temp. The mmol) of 6 in 3 ml of benzene was treated dropwise with 85 µl
solvent was removed, the residue was extracted with 10 ml of ben- (1.17 mmol) of CH2ClI and stirred for 28 h at room temp. A red-
zene and after the extract was concentrated to ca. 2 ml in vacuo, it
was chromatographed on Al2O3 (neutral, activity grade IV, height
of column 5 cm). With benzene/pentane (1:1), a brown-yellow frac-
tion was eluted which after removal of the solvent and recrystalliza-
violet solid 9 precipitated. After addition of 10 ml of benzene to
the reaction mixture, the solid was separated from the mother
liquor, washed with acetone and ether, and dried; yield 38 mg
(10%). The mother liquor was concentrated to 2Ϫ3 ml in vacuo
tion of the residue from ether/pentane gave red-brown crystals of and treated dropwise with 15 ml of pentane. A red-brown solid 8
Eur. J. Inorg. Chem. 1998, 1605Ϫ1617 1611

H. Werner, M. Steinmetz, K. Peters, H. G. von Schnering
FULL PAPER
was formed which was filtered, repeatedly washed with small por-
tions of ether (0°C), and dried; yield 188 mg (58%).
J(RhP) ϭ 248.6 Hz]. Ϫ MS (70 eV); m/z (%) ϭ 492 (1) [Mϩ], 419
(100) [Mϩ Ϫ CH2OAc], 365 (50) [Mϩ Ϫ I], 295 (70) [C5H5RhIϩ],
292 (18) [C5H5RhP(OMe)3ϩ], 168 (58) [C5H5Rhϩ]. Ϫ C11H19I-
O5PRh (492.1): calcd. C 26.85, H 3.89, Rh 20.92; found C 27.06,
H 3.98, Rh 21.35.
8: m. p. 89°C (dec.). Ϫ 1H NMR (200 MHz, C6D6): δ ϭ 5.47
[ddd, J(RhH) ϭ 4.0, J(PH) ϭ 1.4, J(HH) ϭ 5.6 Hz, 1 H, one H
of CH2Cl], 5.27 [dd, J(RhH) ϭ 0.3, J(PH) ϭ 3.2 Hz, 5 H, C5H5],
4.73 [ddd, J(RhH) ϭ 1.8, J(PH) ϭ 9.8, J(HH) ϭ 5.6 Hz, 1 H, one
H of CH2Cl], 3.53 [d, J(PH) ϭ 11.8 Hz, 9 H, P(OMe)3]. Ϫ 13C
NMR (22.5 MHz, C6D6): δ ϭ 92.4 [dd, J(RhC) ϭ J(PC) ϭ 3.7 Hz,
C5H5], 54.0 [d, J(PC) ϭ 5.9 Hz, P(OMe)3], 27.3 [dd, J(RhC) ϭ
26.5, J(PC) ϭ 17.2 Hz, RhCH2]. Ϫ 31P NMR (36.2 MHz, C6D6):
δ ϭ 133.4 [d, J(RhP) ϭ 245.6 Hz]. Ϫ MS (70 eV); m/z (%) ϭ 468
(2) [Mϩ], 419 (31) [Mϩ Ϫ CH2Cl], 341 (8) [Mϩ Ϫ I], 295 (26)
[C5H5RhIϩ], 292 (9) [C5H5RhP(OMe)3ϩ], 168 (28) [C5H5Rhϩ]. Ϫ
C9H16ClIO3PRh (468.5): calcd. C 23.08, H 3.44, Rh 21.97; found
C 23.33, H 3.57, Rh 22.15.
8. Preparation of [ ( η5-C5Me5) Rh( CH2OAc) ( PMe3) I] (15):
Compound 15 was prepared analogously to 4 by using 321.3 mg
(0.47 mmol) of 11 (in 5 ml of benzene) and 308.3 mg (3.76 mmol)
of CH3CO2Na (in 5 ml of 100% acetic acid) as starting materials;
time of reaction 5 h at 25°C. An orange-yellow oil was obtained
which upon addition of 0.5 ml of pentane gave an orange-yellow
microcystalline solid; yield 190 mg (78%); m. p. 83°C (dec.). Ϫ IR
1
(KBr): ν˜ ϭ 1708 cmϪ1 [ν(CϭO)]. Ϫ H NMR (200 MHz, C6D6):
δ ϭ 5.57 [ddd, J(RhH) ϭ 2.1, J(PH) ϭ 8.8, J(HH) ϭ 6.5 Hz, 1 H,
one H of CH2OAc], 5.23 [dd, J(RhH) ϭ 5.1, J(HH) ϭ 6.5 Hz, 1
H, one H of CH2OAc], 1.70 (s, 3 H, OCH3), 1.59 [dd, J(RhH) ϭ
0.3, J(PH) ϭ 2.7 Hz, 15 H, C5Me5], 1.35 [dd, J(RhH) ϭ 0.7,
J(PH) ϭ 10.3 Hz, 9 H, PMe3]. Ϫ 13C NMR (22.5 MHz, C6D6):
δ ϭ 170.3 [s, C(O)CH3], 99.3 [dd, J(RhC) ϭ 4.4, J(PC) ϭ 2.9 Hz,
C5Me5], 60.1 [dd, J(RhC) ϭ 30.2, Hz, J(PC) ϭ 15.4, RhCH2], 21.1
[s, C(O)CH3], 17.4 [d, J(PC) ϭ 32.4 Hz, PMe3], 10.0 [br. s,
C5(CH3)5]. Ϫ 31P NMR (36.2 MHz, C6D6): δ ϭ 4.8 [d, J(RhP) ϭ
157.8 Hz]. Ϫ MS (70 eV); m/z (%) ϭ 514 (6) [Mϩ], 441 (100) [Mϩ
Ϫ CH2OAc], 365 (83) [C5Me5RhIϩ], 314 (2) [C5Me5Rh(PMe3)ϩ],
238 (5) [C5Me5Rhϩ]. Ϫ C16H29IO2PRh (514.2): calcd. C 37.37, H
5.70; found C 37.28, H 6.07.
9: m. p. 96°C (dec.). Ϫ 1H NMR (60 MHz, CD3NO2): δ ϭ 5.97
[dd, J(RhH) ϭ 0.4, J(PH) ϭ 1.3 Hz, 5 H, C5H5], 4.34 [d, J(PH) ϭ
10.8 Hz, 9 H, P(OMe)3]. Ϫ 31P NMR (36.2 MHz, CDCl3): δ ϭ
116.0 [d, J(RhP) ϭ 211.4 Hz]. Ϫ MS (70 eV); m/z (%) ϭ 546 (21)
[Mϩ], 419 (100) [Mϩ Ϫ I], 295 (83) [C5H5RhIϩ], 168 (60)
[C5H5Rhϩ]. Ϫ C8H14I2O3PRh (545.9): calcd. C 17.60, H 2.58;
found C 17.82, H 2.62.
6. Preparation of [ ( η5-C5Me5) Rh( CH2OAc) {P( OMe) 3}I] (13):
A solution of 165.5 mg (0.31 mmol) of 7 in 6 ml of benzene was
treated with a solution of 194.9 mg (1.60 mmol) of CH3CO2Na in
4 ml of acetic acid (100%) and stirred for 6 h at room temp. The
solvent was removed, the residue was extracted with 20 ml of ether,
and after the extract was filtered, the filtrate was concentrated to
ca. 5 ml in vacuo. Pentane (ca. 5 ml) was added and the solution
was stored for 12 h at Ϫ78°C. Orange-red crystals precipitated
which were separated from the mother liquor, washed twice with 2
ml portions of pentane (Ϫ20°C) and dried; yield 134 mg (77%); m.
p. 70°C (dec.). Ϫ IR (KBr): ν˜ ϭ 1712 cmϪ1 [ν(CϭO)]. Ϫ 1H NMR
(200 MHz, C6D6): δ ϭ 5.92 [ddd, J(RhH) ϭ 8.2, J(PH) ϭ 2.2,
J(HH) ϭ 6.0 Hz, 1 H, one H of CH2OAc], 5.10 [ddd, J(RhH) ϭ
0.7, J(PH) ϭ 4.4, J(HH) ϭ 6.0 Hz, 1 H, one H of CH2OAc], 3.53
[d, J(PH) ϭ 10.5 Hz, 9 H, P(OMe)3], 1.78 (s, 3 H, OCH3), 1.70
[dd, J(RhH) ϭ 0.4, J(PH) ϭ 4.2 Hz, 15 H, C5Me5]. Ϫ 13C NMR
(22.5 MHz, C6D6): δ ϭ 170.4 [s, C(O)CH3], 101.4 [dd, J(RhC) ϭ
J(PC) ϭ 4.4 Hz, C5Me5], 57.2 [dd, J(RhC) ϭ 27.2, J(PC) ϭ 17.7
Hz, RhCH2], 54.0 [d, J(PC) ϭ 5.9 Hz, P(OMe)3], 21.2 [s,
C(O)CH3], 9.7 [d, J(RhC) ϭ 1.5 Hz, C5(CH3)5]. Ϫ 31P NMR (36.2
MHz, C6D6): δ ϭ 136.4 [d, J(RhP) ϭ 256.1 Hz]. Ϫ MS (70 eV);
m/z (%) ϭ 562 (1) [Mϩ], 489 (58) [Mϩ Ϫ CH2OAc], 365 (100)
[C5Me5RhIϩ], 362 (1) [C5Me5RhP(OMe)3ϩ], 238 (9) [C5Me5Rhϩ].
Ϫ C16H29IO5PRh (562.2): calcd. C 34.18, H 5.20, Rh 18.31; found
C 34.48, H 5.39, Rh 18.13.
9. Preparation of [ ( η5-C5H5) Rh( CH2OAc) ( PMe3) I] (16): Com-
pound 16 was prepared analogously to 4 by using 140.1 mg (0.33
mmol) of 12 (in 2 ml of benzene) and 270 mg (3.30 mmol) of
CH3CO2Na (in 1 ml of 100% acetic acid) as starting materials; time
of reaction 6 h at 25°C. After recrystallization from ether (25°C to
Ϫ78°C) orange-red crystals were obtained; yield 125 mg (85%); m.
p. 106°C (dec.). Ϫ IR (KBr): ν˜ ϭ 1720 cmϪ1 [ν(CϭO)]. Ϫ 1H NMR
(200 MHz, CDCl3): δ ϭ 6.60 [dd, J(RhH) ϭ 4.9, J(HH) ϭ 5.7 Hz,
1 H, one H of CH2OAc], 5.42 [dd, J(RhH) ϭ 0.4, J(PH) ϭ 1.4 Hz,
5 H, C5H5], 4.97 [ddd, J(RhH) ϭ 2.6, J(PH) ϭ 8.3, J(HH) ϭ 5.7
Hz, 1 H, one H of CH2OAc], 1.78 [dd, J(RhH) ϭ 0.8, J(PH) ϭ
11.1 Hz, 9 H, PMe3], 1.70 (s, 3 H, OCH3). Ϫ 13C NMR (22.5 MHz,
C6D6): δ ϭ 169.5 [s, C(O)CH3], 89.9 [dd, J(RhC) ϭ J(PC) ϭ 3.7
Hz, C5H5], 51.5 [dd, J(RhC) ϭ 27.2, J(PC) ϭ 13.4, RhCH2], 19.6
[d, J(PC) ϭ 33.8 Hz, PMe3], 18.9 [s, C(O)CH3]. Ϫ 31P NMR (36.2
MHz, C6D6): δ ϭ 10.3 [d, J(RhP) ϭ 160.0 Hz]. Ϫ MS (70 eV); m/
z (%) ϭ 444 (3) [Mϩ], 371 (100) [Mϩ Ϫ CH2OAc], 295 (23)
[C5H5RhIϩ], 244 (73) [C5H5Rh(PMe3)ϩ], 168 (35) [C5H5Rhϩ]. Ϫ
C11H19IO2PRh (444.0): calcd. C 29.75, H 4.31, Rh 23.18; found C
30.01, H 4.40, Rh 23.53.
10. Reaction of Compound 14 nBuLi: A solution of 276.5 mg
7. Preparation of [ ( η5-C5H5) Rh( CH2OAc) {P( OMe) 3}I] (14): (0.56 mmol) of 14 in 20 ml of benzene was treated under continu-
Compound 14 was prepared analogously to 13 by using 210.2 mg
(0.45 mmol) of 8 (in 6 ml of benzene) and 250 mg (3.05 mmol) of
ous stirring with 0.8 ml of a 1.41  solution (1.12 mmol) of nBuLi
in hexane at room temp. After the reaction mixture was stirred for
CH3CO2Na (in 2 ml of 100% acetic acid) as starting materials; time 1 h, the solvent was removed and the residue was extracted with
of reaction 90 min at 25°C. Red-brown microcrystalline solid; yield
20 ml of ether. The extract was brought to dryness in vacuo, the
173 mg (78%); m. p. 76°C (dec.). Ϫ IR (KBr): ν˜ ϭ 1700 cmϪ1 oily residue was dissolved in 2 ml of benzene and the solution was
[ν(CϭO)]. Ϫ 1H NMR (200 MHz, C6D6): δ ϭ 6.70 [ddd, J(RhH) ϭ chromatographed on Al2O3 (neutral, activity grade IV, height of
J(HH) ϭ 4.8, J(PH) ϭ 1.4 Hz, 1 H, one H of CH2OAc], 5.83 [ddd,
J(RhH) ϭ 2.4, J(PH) ϭ 8.5, J(HH) ϭ 4.8 Hz, 1 H, one H of
CH2OAc], 5.23 [dd, J(RhH) ϭ 0.5, J(PH) ϭ 3.1 Hz, 5 H, C5H5],
column 5 cm). With hexane, a yellow fraction was eluted from
which upon evaporation of the solvent a light yellow oil 18 was
obtained; yield 8 mg (3%). Further elution with benzene gave a red
3.47 [d, J(PH) ϭ 10.5 Hz, 9 H, P(OMe)3], 1.72 (s, 3 H, OCH3). Ϫ fraction which was brought to dryness in vacuo. The residue was
13C NMR (22.5 MHz, C6D6): δ ϭ 169.9 [s, C(O)CH3], 91.0 [dd,
J(RhC) ϭ J(PC) ϭ 4.2 Hz, C5H5], 53.9 [d, J(PC) ϭ 5.9 Hz,
P(OMe)3], 49.3 [dd, J(RhC) ϭ 25.0, J(PC) ϭ 15.4 Hz, RhCH2],
21.6 [s, C(O)CH3]. Ϫ 31P NMR (36.2 MHz, C6D6): δ ϭ 135.8 [d,
dissolved in 10 ml of ether, the extract was concentrated to ca. 1
ml and then stored for 12 h at Ϫ20°C. A red-brown microcrystal-
line solid 17 precipitated which was washed with small portions of
pentane and dried; yield 21 mg (8%).
1612
Eur. J. Inorg. Chem. 1998, 1605Ϫ1617

A Novel Route to Formaldehyde and Thioformaldehyde Rhodium Complexes
FULL PAPER
1
17: H NMR (60 MHz, CDCl3): δ ϭ 8.20, 7.07 (both m, 5 H,
C6H5), 5.03 [dd, J(RhH) ϭ 0.5, J(PH) ϭ 3.2, 5 H, C5H5], 3.32 [d,
J(PH) ϭ 11.7 Hz, 9 H, P(OMe)3]. Ϫ MS (70 eV); m/z (%) ϭ 496
(7) [Mϩ], 419 (11) [Mϩ Ϫ C6H5], 292 (100) [C5H5RhP(OMe)3ϩ],
168 (69) [C5H5Rhϩ]. Ϫ C14H19IO3PRh (496.1): calcd. C 33.90, H
3.86; found C 33.56, H 3.98.
C11H19F6O5P2Rh (510.1): calcd. C 25.90, H 3.75, Rh 20.17; found
C 25.81, H 3.91, Rh 19.78.
14. Preparation of [ ( η5-C5Me5) Rh{κ2-C,O-CH2OC( Me) O}-
( PMe3) ] PF6 (22): Compound 22 was prepared analogously to 19
by using 67.0 mg (0.13 mmol) of 15 and 36.1 mg (0.14 mmol) of
AgPF6 as starting materials. Orange-yellow microcrystalline solid;
yield 59 mg (85%); dec. temp. 60°C. Ϫ Λ ϭ 84 cm2ΩϪ1molϪ1. Ϫ
18: 1H NMR (60 MHz, C6D6): δ ϭ 7.64, 7.37 (both m, 5 H,
C6H5), 5.17 [dd, J(RhH) ϭ 0.4, J(PH) ϭ 2.2 Hz, 5 H, C5H5], 3.28 IR (nujol): ν˜ ϭ 1608 cmϪ1 [ν(CϭO)]. Ϫ 1H NMR (200 MHz,
[d, J(PH) ϭ 11.4 Hz, 9 H, P(OMe)3] 1.1 (br. m, 9 H, C4H9). Ϫ MS
CD3NO2): δ ϭ 5.86 [ddd, J(RhH) ϭ 4.0, J(PH) ϭ 0.3, J(HH) ϭ
(70 eV); m/z (%) ϭ 462 (2) [Mϩ], 292 (100) [C5H5RhP(OMe)3ϩ], 7.4 Hz, 1 H, one H of RhCH2], 5.55 [ddd, J(RhH) ϭ J(HH) ϭ
168 (56) [C5H5Rhϩ].
7.4, J(PH) ϭ 27.7 Hz, 1 H, one H of RhCH2], 2.16 (s, 3 H, CH3),
1.73 [dd, J(RhH) ϭ 0.3, J(PH) ϭ 2.6 Hz, 15 H, C5Me5], 1.48 [dd,
J(RhH) ϭ 0.8, J(PH) ϭ 10.4 Hz, 9 H, PMe3]. Ϫ 13C NMR (50.3
MHz, CD3NO2): δ ϭ 186.1 (s, CϭO), 101.4 [dd, J(RhC) ϭ
J(PC) ϭ 3.0 Hz, C5Me5], 84.6 [dd, J(RhC) ϭ 28.5 Hz, RhCH2],
18.8 [s, C(O)CH3], 13.8 [d, J(PC) ϭ 31.0 Hz, PMe3], 9.5 [br. s,
C5(CH3)5]. Ϫ 31P NMR (36.2 MHz, CD3NO2): δ ϭ 2.3 [d,
J(RhP) ϭ 159.3 Hz]. Ϫ C16H29F6O2P2Rh (532.3): calcd. C 36.11,
H 5.49, Rh 19.34; found C 36.05, H 5.31, Rh 19.70.
11. Preparation of [ ( η5-C5Me5) Rh{κ2-C,O-CH2OC( Me) O}-
( CO) ] PF6 (19): A solution of 81.2 mg (0.17 mmol) of 4 in 5 ml of
acetone was treated under continuous stirring with a solution of
42.9 mg (0.17 mmol) of AgPF6 in 2 ml of acetone at room temp.
A pale yellow precipitate of AgI was rapidly formed. After the reac-
tion mixture was stirred for 20 min, it was filtered and the filtrate
was concentrated to ca. 2 ml in vacuo. Upon addition of 20 ml of
ether, the solution was rigorously stirred until a yellow microcrys-
talline solid precipitated. This was filtered, washed twice with 5 ml
portions of ether and dried; yield 69 mg (83%); dec. temp. 109°C.
Ϫ Λ ϭ 66 cm2ΩϪ1molϪ1. Ϫ IR (nujol): ν˜ ϭ 2030 cmϪ1 [ν(CO)],
15. Preparation of [ ( η5-C5H5) Rh{κ2-C,O-CH2OC( Me) O}-
( PMe3) ] PF6 (23): Compound 23 was prepared analogously to 19
by using 96.2 mg (0.22 mmol) of 16 and 58.0 mg (0.23 mmol) of
AgPF6 as starting materials. Orange-yellow microcrystalline solid;
yield 83 mg (81%); dec. temp. 68°C. Ϫ Λ ϭ 78 cm2ΩϪ1molϪ1. Ϫ
IR (nujol): ν˜ ϭ 1605 cmϪ1 [ν(CϭO)]. Ϫ 1H NMR (200 MHz,
CD3NO2): δ ϭ 7.37 [ddd, J(RhH) ϭ 4.2, J(PH) ϭ 0.8, J(HH) ϭ
6.8 Hz, 1 H, one H of RhCH2], 5.60 [ddd, J(RhH) ϭ 0.3, J(PH) ϭ
19.7, J(HH) ϭ 6.8 Hz, 1 H, one H of RhCH2], 5.57 [dd, J(RhH) ϭ
0.6, J(PH) ϭ 1.3 Hz, 5 H, C5H5], 2.18 (s, 3 H, CH3), 1.63 [dd,
1
1605 [ν(CϭO)]. Ϫ H NMR (200 MHz, CD3NO2): δ ϭ 6.23 [dd,
J(RhH) ϭ 0.5, J(HH) ϭ 6.0 Hz, 1 H, one H of RhCH2], 5.63 [dd,
J(RhH) ϭ 4.0, J(HH) ϭ 6.0 Hz, 1 H, one H of RhCH2], 2.23 (s,
3 H, CH3), 1.92 [d, J(RhH) ϭ 0.4 Hz, 15 H, C5Me5]. Ϫ 13C NMR
(22.5 MHz, CD3NO2): δ ϭ 190.7 [d, J(RhC) ϭ 70.5 Hz, Rh(CO)],
187.9 (s, CϭO), 107.6 [d, J(RhC) ϭ 5.2 Hz, C5Me5], 81.0 [d,
J(RhC) ϭ 23.5 Hz, RhCH2], 18.6 [s, C(O)CH3], 9.3 [br. s,
C5(CH3)5]. Ϫ C14H20F6O3PRh (484.2): calcd. C 37.74, H 4.17; J(RhH) ϭ 0.8, J(PH) ϭ 11.5 Hz, 9 H, PMe3]. Ϫ 13C NMR (22.5
found C 37.44, H 4.31.
MHz, CD3NO2): δ ϭ 187.5 (s, CϭO), 90.6 [dd, J(RhC) ϭ 5.2,
J(PC) ϭ 2.9 Hz, C5H5], 75.4 [dd, J(RhC) ϭ 25.7, J(PC) ϭ 14.7
Hz, RhCH2], 17.0 [s, C(O)CH3], 16.2 [d, J(PC) ϭ 33.1 Hz, PMe3].
12. Preparation of [ ( η5-C5Me5) Rh{κ2-C,O-CH2OC( Me) O}-
{P( OMe) 3}] PF6 (20): Compound 20 was prepared analogously to
19 by using 131.7 mg (0.24 mmol) of 13 and 59.9 mg (0.24 mmol)
of AgPF6 as starting materials. Yellow microcrystalline solid; yield
131 mg (94%); dec. temp. 66°C. Ϫ Λ ϭ 80 cm2ΩϪ1molϪ1. Ϫ IR
(nujol): ν˜ ϭ 1600 cmϪ1 [ν(CϭO)]. Ϫ 1H NMR (200 MHz,
CD3NO2): δ ϭ 5.91, 5.77 [both part of an ABPX spin system; from
1H{31P}: J(RhH) ϭ 0.3 and 4.2, J(HH) ϭ 6.4 Hz, 1H each,
RhCH2], 3.77 [d, J(PH) ϭ 11.8 Hz, 9 H, P(OMe)3], 2.14 (s, 3 H,
CH3), 1.76 [dd, J(RhH) ϭ 0.4, J(PH) ϭ 4.4 Hz, 15 H, C5Me5]. Ϫ
13C NMR (50.3 MHz, CD3NO2): δ ϭ 186.3 (s, CϭO), 103.2 [dd,
J(RhC) ϭ 5.3, J(PC) ϭ 3.4 Hz, C5Me5], 82.1 [dd, J(RhC) ϭ 25.9,
J(PC) ϭ 23.1 Hz, RhCH2], 53.8 [d, J(PC) ϭ 4.7 Hz, P(OMe)3],
18.5 [s, C(O)CH3], 9.2 [br. s, C5(CH3)5]. Ϫ 31P NMR (36.2 MHz,
CD3NO2): δ ϭ 129.4 [d, J(RhP) ϭ 256.1 Hz]. Ϫ C16H29F6O5P2Rh
(580.3): calcd. C 33.12, H 5.04; found C 33.38, H 5.26.
Ϫ
31P NMR (36.2 MHz, CD3NO2): δ ϭ 12.5 [d, J(RhP) ϭ 150.3
Hz]. Ϫ C11H19F6O2P2Rh (462.1): calcd. C 28.59, H 4.15, Rh 22.27;
found C 28.42, H 4.11, Rh 22.00.
16. Preparation of [ ( η5-C5Me5) Rh( η2-CH2O) {P( OMe) 3}] (24):
A suspension of 89.7 mg (0.15 mmol) of 20 in 5 ml of methanol
was treated at 0°C under continuous stirring with 98.1 mg (1.40
mmol) of KOH. A yellow-brown solution was formed of which
after it was stirred for 10 min at 0°C, the solvent was removed in
vacuo. The residue was extracted twice with 5 ml of cold ether
(0°C) and the combined extracts were brought by cooling with an
ice bath to dryness in vacuo. The remaining yellow-brown oil was
dissolved in 2 ml of pentane (0°C) and the solution was stored for
10 h at Ϫ78°C. A yellow-brown microcrystalline solid precipitated
which was filtered, washed twice with small quantities of pentane
(Ϫ20°C) and dried; yield of oily product 38 mg (62%), yield of
solid material 15 mg (26%); m. p. 36°C (dec.). Ϫ IR (C6H6): ν˜ ϭ
2805 cmϪ1 [ν(CH2)], 1220 [ν(CϪO)]. Ϫ 1H NMR (200 MHz,
C6D6): δ ϭ 4.62 (m, 2 H, CH2O), 3.52 [d, J(PH) ϭ 12.2 Hz, 9 H,
P(OMe)3], 1.89 [dd, J(RhH) ϭ 0.5, J(PH) ϭ 3.4 Hz, 15 H, C5Me5].
13. Preparation of [ ( η5-C5H5) Rh{κ2-C,O-CH2OC( Me) O}-
{P( OMe) 3}] PF6 (21): Compound 21 was prepared analogously to
19 by using 90.2 mg (0.18 mmol) of 14 and 45.4 mg (0.18 mmol)
of AgPF6 as starting materials. Yellow microcrystalline solid; yield
87 mg (94%); dec. temp. 112° C. Ϫ Λ ϭ 65 cm2ΩϪ1molϪ1. Ϫ IR
(nujol): ν˜ ϭ 1600 cmϪ1 [ν(CϭO)]. Ϫ 1H NMR (200 MHz,
CD3NO2): δ ϭ 7.37 [ddd, J(RhH) ϭ 4.5, J(PH) ϭ 1.4, J(HH) ϭ
6.2 Hz, 1 H, one H of RhCH2], 5.88 [ddd, J(RhH) ϭ 0.3, J(PH) ϭ
28.3, J(HH) ϭ 6.2 Hz, 1 H, one H of RhCH2], 5.85 [dd, J(RhH) ϭ
0.6, J(PH) ϭ 2.8 Hz, 5 H, C5H5], 3.80 [d, J(PH) ϭ 12.0 Hz, 9 H,
P(OMe)3], 2.17 (s, 3 H, CH3). Ϫ 13C NMR (22.5 MHz, CD3NO2):
δ ϭ 188.1 (s, CϭO), 91.4 [dd, J(RhC) ϭ J(PC) ϭ 4.4 Hz, C5H5],
73.0 [dd, J(RhC) ϭ 23.5, J(PC) ϭ 20.6 Hz, RhCH2], 54.3[d,
J(PC) ϭ 4.4 Hz, P(OMe)3], 17.9 [s, C(O)CH3]. Ϫ 31P NMR (36.2
Ϫ
13C NMR (50.3 MHz, C6D6): δ ϭ 97.6 [dd, J(RhC) ϭ J(PC) ϭ
4.4 Hz, C5Me5], 78.1 [dd, J(RhC) ϭ 12.0, J(PC) ϭ 5.9 Hz, CH2O],
51.1 [br. s, P(OMe)3], 10.0 [s, C5(CH3)5]. Ϫ 31P NMR (36.2 MHz,
C6D6): δ ϭ 149.2 [d, J(RhP) ϭ 311.1 Hz]. Ϫ MS (70 eV); m/z
(%) ϭ 392 (2) [Mϩ], 390 (32) [Mϩ Ϫ 2 H], 362 (100) [Mϩ Ϫ CH2O],
238 (49) [C5Me5Rhϩ], 30 (2) [CH2Oϩ]. Ϫ C14H26O4PRh (392.2):
calcd. C 42.87, H 6.68; found C 42.59, H 6.70.
17. Preparation of [ ( η5-C5H5) Rh( η2-CH2O) {P( OMe) 3}] (25):
Compound 25 was prepared analogously to 24 by using 95.3 mg
(0.19 mmol) of 21 and 88.7 mg (1.26 mmol) of KOH as starting
MHz, CD3NO2):
δ ϭ 128.2 [d, J(RhP) ϭ 242.7 Hz]. Ϫ
Eur. J. Inorg. Chem. 1998, 1605Ϫ1617
1613

H. Werner, M. Steinmetz, K. Peters, H. G. von Schnering
FULL PAPER
materials. Yellow-brown solid; yield of oily product 43 mg (71%),
Ϫ
31P NMR (36.2 MHz, C6D6): δ ϭ 10.0 [d, J(RhP) ϭ 153.3 Hz].
yield of solid material 13 mg (22%); m. p. 43°C (dec.). Ϫ IR (C6H6): Ϫ C16H21IO2PRh (506.1): calcd. C 37.97, H 4.18; found C 37.67,
1
ν˜ ϭ 2825 cmϪ1 [ν(CH2)], 1232 [ν(CϪO)]. Ϫ H NMR (200 MHz,
C6D6): δ ϭ 5.56 [ddd, J(RhH) ϭ 2.5, J(PH) ϭ 0.5, J(HH) ϭ 21.5
Hz, 1 H, one H of CH2O], 5.29 [dd, J(RhH) ϭ 0.8, J(PH) ϭ 2.6
Hz, 5 H, C5H5], 4.60 [ddd, J(RhH) ϭ 2.0, J(PH) ϭ 5.1, J(HH) ϭ
21.5 Hz, 1 H, one H of CH2O], 3.80 [d, J(PH) ϭ 12.4 Hz, 9 H,
P(OMe)3]. Ϫ 13C NMR (100.6 MHz, C6D6): δ ϭ 86.1 [dd,
J(RhC) ϭ J(PC) ϭ 3.1 Hz, C5H5], 72.6 [dd, J(RhC) ϭ 13.6,
J(PC) ϭ 4.9 Hz, CH2O], 51.6 [br. s, P(OMe)3]. Ϫ 31P NMR (36.2
MHz, C6D6): δ ϭ 150.1 [d, J(RhP) ϭ 299.2 Hz]. Ϫ C9H16O4PRh
(322.1): calcd. C 33.56, H 5.01; found C 33.54, H 4.81.
H 4.61.
21. Preparation of [ ( η5-C5H5) Rh{κ2-C,O-CH2OC( Ph) O}-
( PMe3) ] PF6 (29): A solution of 60.7 mg (0.12 mmol) of 28 in 3
ml of acetone was treated dropwise with a solution of 30.4 mg (0.12
mmol) of AgPF6 in 2 ml of acetone. The reaction mixture was
stirred for 10 min at room temp. and then filtered. The filtrate was
concentrated to ca. 2 ml in vacuo and under vigorous stirring 15
ml of ether was added. An orange-yellow precipitate was formed
which was separated from the mother liquor, washed twice with
ether and dried; yield 52 mg (83%); dec. temp. 75°C. Ϫ IR (nujol):
1
ν˜ ϭ 1602 cmϪ1 [ν(CϭO)]. Ϫ H NMR (60 MHz, (CD3)2CO): δ ϭ
18. Preparation of [ ( η5-C5Me5) Rh( η2-CH2O) ( PMe3) ] (26):
Compound 26 was prepared analogously to 24 by using 105.6 mg
(0.20 mmol) of 22 and 85.9 mg (1.22 mmol) of KOH as starting
materials. Brownish microcrystalline solid; yield of oily product 39
mg (56%), yield of solid material 20 mg (29%); m. p. 25°C (dec.).
Ϫ IR (C6H6): ν˜ ϭ 2800 cmϪ1 [ν(CH2)], 1210 [ν(CϪO)]. Ϫ 1H NMR
(200 MHz, C6D6): δ ϭ 4.48 [ddd, J(RhH) ϭ 3.0, J(PH) ϭ 0.6,
J(HH) ϭ 18.2 Hz, 1 H, one H of CH2O], 4.15 [ddd, J(RhH) ϭ 2.4,
J(PH) ϭ 6.1, J(HH) ϭ 18.2 Hz, 1 H, one H of CH2O], 1.87 [dd,
J(RhH) ϭ 0.4, J(PH) ϭ 2.2 Hz, 15 H, C5Me5], 0.99 [dd, J(RhH) ϭ
8.1, 7.7 (both m, 5 H, C6H5), 6.17 (m, 1 H, one H of RhCH2), 5.80
[dd, J(RhH) ϭ 0.6, J(PH) ϭ 1.2 Hz, 5 H, C5H5], 1.73 [dd,
J(RhH) ϭ 0.8, J(PH) ϭ 11.8 Hz, 9 H, PMe3], signal of one H of
RhCH2 partly covered by signal of C5H5. Ϫ 31P NMR (36.2 MHz,
CD3NO2): δ ϭ 12.8 [d, J(RhP) ϭ 150.4 Hz]. Ϫ C16H21F6O2P2Rh
(524.2): calcd. C 36.66, H 4.04; found C 36.73, H 4.29.
22. Thermal Decomposition of 24: A solution of 36.4 mg (0.09
mmol) of 24 in 0.5 ml of benzene was stored for 5 h at room temp.
1
The reaction was controlled by measuring the H-NMR spectrum
0.9, J(PH) ϭ 8.9 Hz, 9 H, PMe3]. Ϫ 13C NMR (50.3 MHz, C6D6): in time intervals of ca. 20 min. After 5 h, the signals of 24 disap-
δ ϭ 96.5 [dd, J(RhC) ϭ J(PC) ϭ 3.3 Hz, C5Me5], 74.4 [dd,
J(RhC) ϭ 14.0, J(PC) ϭ 6.6 Hz, CH2O], 15.8 [d, J(PC) ϭ 25.7 Hz,
PMe3], 10.7 [s, C5(CH3)5]. Ϫ 31P NMR (36.2 MHz, C6D6): δ ϭ 2.8
[d, J(RhP) ϭ 190.3 Hz]. Ϫ MS (70 eV); m/z (%) ϭ 344 (2) [Mϩ],
342 (23) [Mϩ Ϫ 2 H], 314 (100) [Mϩ Ϫ CH2O], 238 (25)
[C5Me5Rhϩ], 30 (2) [CH2Oϩ]. Ϫ C14H26OPRh (344.3): calcd. C
48.85, H 7.61 Rh 29.83; found C 48.34, H 7.55, Rh 29.50.
peared and new signals corresponding to 30[22] were observed; yield
ca 85%.
23. Thermal Decomposition of 25: A solution of 50.6 mg (0.16
mmol) of 25 in 0.5 ml of benzene was stored for 6 d at room temp.
1
The reaction was controlled by measuring the H-NMR spectrum
in time intervals of ca. 2Ϫ3 h. After 6 d, the signals of 25 disap-
peared and new signals corresponding to 31 and 32[33] were ob-
served; yield almost quantitative; ratio 31/32 ϭ 70:30.
24. Preparation of [ {( η5-C5H5) RhP( OMe) 3}2] (31): A solution
19. Preparation of [ ( η5-C5H5) Rh( η2-CH2O) ( PMe3) ] (27):
Compound 27 was prepared analogously to 24 by using 98.7 mg
(0.21 mmol) of 23 and 103.6 mg (1.48 mmol) of KOH as starting of 88.2 mg (0.27 mmol) of 25 in 0.6 ml of benzene was stored for
materials. Brownish microcrystalline solid; yield of oily product 39
mg (56%), yield of solid material 20 mg (29%); m. p. 39°C (dec.).
Ϫ IR (C6H6): ν˜ ϭ 2790 cmϪ1 [ν(CH2)], 1215 [ν(CϪO)]. Ϫ 1H NMR
(60 MHz, C6D6): δ ϭ 5.70 [ddd, J(RhH) ϭ 2.8, J(PH) ϭ 0.5,
J(HH) ϭ 19.8 Hz, 1 H, one H of CH2O], 5.07 [dd, J(RhH) ϭ 0.3,
7 d at room temp. A characteristic change of color from yellow-
brown to deep green occurred. The solvent was removed, the resi-
due was washed twice with 2 ml portions of pentane and then ex-
tracted with 10 ml of ether . The extract was concentrated to ca. 1
ml in vacuo and stored for 12 h at Ϫ78°C. A green microcrystalline
J(PH) ϭ 1.2 Hz, 5 H, C5H5], 4.03 [ddd, J(RhH) ϭ 2.1, J(PH) ϭ solid precipitated which was repeatedly washed with small quanti-
5.0, J(HH) ϭ 19.8 Hz, 1 H, one H of CH2O], 0.90 [dd, J(RhH) ϭ
0.8, J(PH) ϭ 10.4 Hz, 9 H, PMe3]. Ϫ 13C NMR (100.6 MHz,
ties of pentane and dried; yield 30.5 mg (39%). Ϫ 1H NMR (60
MHz, C6D6): δ ϭ 5.57 [dd, J(RhH) ϭ 0.6, J(PH) ϭ 2.2 Hz, 5 H,
C6D6): δ ϭ 85.0 [br. s, C5H5], 67.9 [m, CH2O], 17.7 [d, J(PC) ϭ C5H5], 3.57 [d, J(PH) ϭ 13.1 Hz, 9 H, P(OMe)3]. Ϫ 31P NMR
28.4 Hz, PMe3]. Ϫ 31P NMR (36.2 MHz, C6D6): δ ϭ 8.0 [d,
(36.2 MHz, C6D6): δ ϭ 161.8 [pseudo-quartet, spectrum of
J(RhP) ϭ 193.5 Hz]. Ϫ MS (70 eV); m/z (%) ϭ 274 (4) [Mϩ], 272 AAЈXXЈ type, N ϭ J(AX) ϩ J(AXЈ) ϭ 277.6 Hz]. Ϫ MS (70 eV);
(30) [Mϩ Ϫ 2 H], 244 (100) [Mϩ Ϫ CH2O], 168 (50) [C5H5Rhϩ],
30 (4) [CH2Oϩ]. Ϫ C9H16OPRh (274.1): calcd. C 39.44, H 5.88,
Rh 37.54; found C 39.73, H 6.16, Rh 38.09.
m/z (%) ϭ 584 (8) [Mϩ], 460 (6) [Mϩ Ϫ P(OMe)3], 292 (88) [M/2ϩ],
233 (100) [(C5H5)2Rhϩ], 168 (67) [C5H5Rhϩ]. Ϫ C16H28O6P2Rh2
(584.2): calcd. C 32.90, H 4.83; found C 32.96, H 4.82.
25. Preparation of [ ( η5-C5Me5) Rh( CH3) ( CO) {P( OMe) 3}] -
CF3SO3 (33): A solution of 47.1 mg (0.12 mmol) of 24 in 3 ml of
ether was treated dropwise with 14 µl (0.12 mmol) of CF3SO3CH3
at 0°C. Evolution of gas was observed and a pale yellow solid pre-
cipitated. After the cooling vessel was removed, the solid was sepa-
rated from the mother liquor, repeatedly washed with ether and
dried; yield 37 mg (55%). Ϫ IR (CH2Cl2): ν˜ ϭ 2060 cmϪ1 [ν(CO)].
20. Preparation of [ ( η5-C5H5) Rh{CH2OC( O) Ph}( PMe3) I]
(28): A solution of 87.1 mg (0.21 mmol) of 12 in 4 ml acetone/
benzene (1:1) was treated with 79.3 mg (0.49 mmol) of PhCO2K
and stirred for 20 h at 50Ϫ60°C. After the reaction mixture was
cooled to room temp., the solvent was removed and the residue was
extracted with 15 ml of ether. The extract was concentrated to ca.
3 ml in vacuo and upon storing for 6 h at Ϫ78°C gave orange-red
crystals. The crystals were separated from the mother liquor,
washed twice with pentane (0°C) and dried; yield 59 mg (56%); m.
p. 142°C (dec.). Ϫ IR (KBr): ν˜ ϭ 1712 cmϪ1 [ν(CϭO)]. Ϫ 1H NMR
(200 MHz, C6D6): δ ϭ 8.1, 7.2 (both m, 5 H, C6H5), 7.00 [ddd,
J(RhH) ϭ 4.8, J(PH) ϭ 0.3, J(HH) ϭ 5.6 Hz, 1 H, one H of
RhCH2], 5.33 [ddd, J(RhH) ϭ 1.4, J(PH) ϭ 8.4, J(HH) ϭ 5.6 Hz,
1 H, one H RhCH2], 5.05 [dd, J(RhH) ϭ 0.6, J(PH) ϭ 1.4 Hz, 5
H, C5H5], 1.37 [dd, J(RhH) ϭ 0.8, J(PH) ϭ 11.2 Hz, 9 H, PMe3].
1
Ϫ H NMR (60 MHz, CD2Cl2): δ ϭ 3.78 [d, J(PH) ϭ 11.8 Hz, 9
H, P(OMe)3], 1.86 [dd, J(RhH) ϭ 0.4, J(PH) ϭ 5.0 Hz, 15 H,
C5Me5], 0.75 [dd, J(RhH) ϭ 2.2, J(PH) ϭ 6.1 Hz, 3 H, RhCH3].
Ϫ
31P NMR (36.2 MHz, CDCl3): δ ϭ 120.2 [d, J(RhP) ϭ 218.8
Hz]. Ϫ C16H27F3O7PRhS (554.3): calcd. C 34.67, H 4.91; found C
34.31, H 5.00.
26. Preparation of [ ( η5-C5Me5) Rh( CH3) ( CO) ( PMe3) ] CF3SO3
(34): Compound 34 was prepared analogously to 33 by using 44.6
1614
Eur. J. Inorg. Chem. 1998, 1605Ϫ1617

A Novel Route to Formaldehyde and Thioformaldehyde Rhodium Complexes
mg (0.13 mmol) of 26 and 15 µl (0.13 mmol) of CF3SO3CH3 as PMe3]. Ϫ 31P NMR (36.2 MHz, C6D6): δ ϭ 7.3 [d, J(RhP) ϭ 150.0
FULL PAPER
starting materials. Pale yellow solid; yield 45 mg (69%). Ϫ IR
(CH2Cl2): ν˜ ϭ 2045 cmϪ1 [ν(CO)]. Ϫ 1H NMR (200 MHz,
CD2Cl2): δ ϭ 1.85 [dd, J(RhH) ϭ 0.3, J(PH) ϭ 3.1 Hz, 15 H,
C5Me5], 1.55 [dd, J(RhH) ϭ 0.8, J(PH) ϭ 11.0 Hz, 9 H, PMe3],
0.51 [dd, J(RhH) ϭ 2.2, J(PH) ϭ 5.7 Hz, 3 H, RhCH3]. Ϫ 31P
NMR (36.2 MHz, CDCl3): δ ϭ 4.8 [d, J(RhP) ϭ 126.5 Hz]. Ϫ
C16H27F3O4PRhS (506.3): calcd. C 37.95 H 5.38; found C 37.56,
H 5.23.
Hz]. Ϫ MS (70 eV); m/z (%) ϭ 371 (95) [Mϩ Ϫ CH2SAc], 333 (88)
[Mϩ Ϫ I], 295 (27) [C5H5RhIϩ], 244 (100) [C5H5Rh(PMe3)ϩ], 168
(57) [C5H5Rhϩ]. Ϫ C11H19IOPRhS (460.1): calcd. C 28.71, H 4.16;
found C 28.48, H 3.84.
30. Preparation of [ ( η5-C5H5) Rh( PMe3) ( SAc) I] (40): a) A
solution of 50.3 mg (0.11 mmol) of 38 in 1.5 ml of benzene was
chromatographed on Al2O3 (neutral, activity grade IV, height of
column 4 cm). With benzene, an orange-yellow fraction was eluted
from which the solvent was removed in vacuo. To the oily residue
27. Preparation of [ ( η5-C5H5) Rh( CH3) ( CO) ( PMe3) ] CF3SO3
(35): Compound 35 was prepared analogously to 33 by using 60.3 1 ml of pentane was added and after the mixture was stirred for 1
mg (0.22 mmol) of 27 and 25 µl (0.22 mmol) of CF3SO3CH3 as h an orange solid was obtained; yield 45 mg (91%). Ϫ b) A solution
starting materials. The crude product (dark oil) was dissolved in 8
ml of CH2Cl2, the solution was filtered and the filtrate was brought
to dryness in vacuo. The residue was dissolved in 1 ml of methanol
of 131.8 mg (0.25 mmol) of 36 in 1.5 ml of benzene and 3 ml of
thioacetic acid was treated with 30.1 mg (0.26 mmol) of KSAc and
stirred for 2 h at room temp. The solvent was removed, the residue
and the solution was layered with 10 ml of ether. Light brown crys- was extracted with 10 ml of benzene and the extract was concen-
tals precipitated which were separated from the mother liquor,
trated to ca. 2 ml in vacuo. The 1H-NMR spectrum of the solution
washed with ether and dried; yield 16 mg (16%). Ϫ IR (CH2Cl2): revealed that the major component of the crude product was 38.
ν˜ ϭ 2055 cmϪ1 [ν(CO)]. Ϫ 1H NMR (200 MHz, CD3NO2): δ ϭ The solution was chromatographed on Al2O3 (neutral, activity
5.73 [dd, J(RhH) ϭ 0.3, J(PH) ϭ 1.4 Hz, 5 H, C5H5], 1.85 [dd,
J(RhH) ϭ 0.9, J(PH) ϭ 10.8 Hz, 9 H, PMe3], 1.03 [dd, J(RhH) ϭ were eluted. The first fraction contained a mixture of products
2.3, J(PH) ϭ 5.2 Hz, 3 H, RhCH3]. Ϫ 31P NMR (36.2 MHz,
among which 37 could be detected. The second fraction was
(CD3)2CO): δ ϭ 12.8 [d, J(RhP) ϭ 125.1 Hz]. Ϫ C11H17F3O4PRhS worked up analogously as described for a) to give an orange mi-
grade IV, height of column 4 cm) and with benzene two fractions
(436.2): calcd. C 30.29 H 3.91; found C 29.80, H 4.08.
crocrystalline solid; yield 80 mg (72%); m. p. 118°C (dec.). Ϫ IR
1
(C6H6): ν˜ ϭ 1620 cmϪ1 [ν(CϭO)]. Ϫ H NMR (200 MHz, C6D6):
28. Preparation of [ ( η5-C5H5) Rh( PMe3) ( SAc) 2] (37): A solu-
tion of 146 mg (0.35 mmol) of 36 in 1 ml of benzene and 2 ml of
thioacetic acid was treated with 302.9 mg (2.65 mmol) of KSAc at
room temp. After the reaction mixture was stirred for 1 h, the sol-
vent was removed and the residue was extracted with 10 ml of
benzene. The extract was brought to drynesss in vacuo and upon
addition of 1 ml of ether and 1 ml of pentane the oily residue was
crystallized to give an orange solid; yield 105 mg (76%); m. p.
150°C (dec.). Ϫ IR (C6H6): ν˜ ϭ 1625 cmϪ1 [ν(CϭO)]. Ϫ 1H NMR
δ ϭ 5.20 [dd, J(RhH) ϭ 0.3, J(PH) ϭ 1.9 Hz, 5 H, C5H5], 2.57 (s,
3 H, SCCH3), 1.50 [dd, J(RhH) ϭ 0.7, J(PH) ϭ 11.9, 9 H, PMe3].
Ϫ MS (70 eV); m/z (%) ϭ 446 (1) [Mϩ], 371 (50) [Mϩ Ϫ SAc], 319
(17) [Mϩ Ϫ I], 295 (16) [C5H5RhIϩ], 244 (60) [C5H5Rh(PMe3)ϩ],
168 (36) [C5H5Rhϩ]. Ϫ C10H17IOPRhS (446.1): calcd. C 26.93, H
3.84; found C 27.24, H 3.81.
31. Preparation of [ ( η5-C5Me5) Rh( CH2SAc) {P( OMe) 3}I] (43):
A solution of 87.9 mg (0.14 mmol) of 41 in 3 ml of benzene was
(60 MHz, C6D6): δ ϭ 5.40 [dd, J(RhH) ϭ 0.4, J(PH) ϭ 2.0 Hz, 5 treated under stirring with a solution of 16.0 mg (0.14 mmol) of
H, C5H5], 2.57 (s, 6 H, SCCH3), 1.32 [dd, J(RhH) ϭ 0.9, J(PH) ϭ
11.7 Hz, 9 H, PMe3]. Ϫ 31P NMR (36.2 MHz, C6D6): δ ϭ 12.2 [d,
KSAc in 1.5 ml of ethanol. After the reaction mixture was continu-
ously stirred for 1 h at room temp., the solvent was removed and
J(RhP) ϭ 120.0 Hz]. Ϫ MS (70 eV); m/z (%) ϭ 394 (7) [Mϩ], 319 the residue was extracted with 10 ml of ether. The extract was
(100) [Mϩ
Ϫ
SAc], 244 (65) [C5H5Rh(PMe3)ϩ], 168 (16)
brought to dryness in vacuo, the oily residue was washed with 0.5
[C5H5Rhϩ]. Ϫ C12H20O2PRhS2 (394.3): calcd. C 36.58, H 5.11; ml of ethanol and 3 ml of pentane was added. Upon storing for 12
found C 36.18, H 5.09.
h at Ϫ78°C an orange-red solid precipitated which was washed
twice with pentane and dried; yield 61 mg (75%). Ϫ IR (C6H6):
ν˜ ϭ 1670 cmϪ1 [ν(CϭO)]. Ϫ 1H NMR (200 MHz, CDCl3): δ ϭ
3.77 [d, J(PH) ϭ 11.2 Hz, 9 H, P(OMe)3], 3.20 [ddd, J(RhH) ϭ
5.2, J(PH) ϭ 2.6, J(HH) ϭ 8.4 Hz, 1 H, one H of RhCH2], 2.99
[ddd, J(RhH) ϭ 3.2, J(PH) ϭ 5.0, J(HH) ϭ 8.4 Hz, 1 H, one H
of RhCH2], 2.23 (s, 3 H, SCCH3), 1.87 [dd, J(RhH) ϭ 0.3, J(PH) ϭ
4.5 Hz, 15 H, C5Me5]. Ϫ 13C NMR (22.5 MHz, C6D6): δ ϭ 198.9
(s, CϭO), 101.0 [dd, J(RhC) ϭ J(PC) ϭ 4.4 Hz, C5Me5], 54.2 [d,
J(PC) ϭ 6.6 Hz, P(OMe)3], 29.7 (s, SCCH3), 9.6 [d, J(RhC) ϭ 1.5
Hz, C5(CH3)5], 5.3 [dd, J(RhC) ϭ 27.2, J(PC) ϭ 19.1 Hz, RhCH2].
29. Preparation of [ ( η5-C5H5) Rh( CH2SAc) ( PMe3) I] (38): A
solution of 104.2 mg (0.25 mmol) of 36 in 4 ml C6H6/EtOH (1:1)
was treated with 28.3 mg (0.25 mmol) of KSAc and stirred for 1 h
at room temp. The solvent was removed, the residue was extracted
with 10 ml of benzene and the extract was brought to dryness in
vacuo. The residue was now extracted with 5 ml of pentane and
the dark red extract was worked up as described below. The re-
maining solid was dissolved in 2 ml of ether and then 2 ml of
pentane was added. After the solution was stored for 12 h at
Ϫ78°C orange-red crystals of 38 were formed which were separated
from the mother liquor, washed twice with pentane and dried; yield
67 mg. The pentane extract was also brought to dryness in vacuo,
the residue was dissolved in 1 ml of benzene and the solution was
chromatographed on Al2O3 (neutral, activity grade IV, height of
column 4 cm). With benzene, a red fraction was eluted which upon
work up gave red-brown needles of 39[3]; yield 23 mg (21%). Ϫ 38:
Ϫ
31P NMR (36.2 MHz, C6D6): δ ϭ 133.6 [d, J(RhP) ϭ 248.6 Hz].
Ϫ MS (70 eV); m/z (%) ϭ 489 (24) [Mϩ Ϫ CH2SAc], 365 (41)
[C5Me5RhIϩ], 362 (100) [Mϩ
Ϫ CH2SAc Ϫ I], 238 (46)
[C5Me5Rhϩ]. Ϫ C16H29IO4PRhS (578.3): calcd. C 33.23, H 5.06;
found C 33.47, H 5.18.
32. Preparation of [ ( η5-C5Me5) Rh( CH2SAc) ( PMe) 3I] (44):
Compound 44 was prepared analogously to 43 by using 87.1 mg
(0.15 mmol) of 42 and 17.1 mg (0.15 mmol) of KSAc as starting
materials. The ether extract was concentrated to ca. 1 ml in vacuo
m. p. 142°C (dec.). Ϫ IR (C6H6): ν˜ ϭ 1670 cmϪ1 [ν(CϭO)]. Ϫ H
NMR (200 MHz, C6D6): δ ϭ 4.87 [dd, J(RhH) ϭ 0.5, J(PH) ϭ
1.6 Hz, 5 H, C5H5], 4.10 [ddd, J(RhH) ϭ 4.8, J(PH) ϭ 3.8,
1
J(HH) ϭ 9.2 Hz, 1 H, one H of RhCH2], 3.44 [ddd, J(RhH) ϭ and then stored for 12 h at Ϫ78°C. Orange microcrystalline solid;
2.2, J(PH) ϭ 6.9, J(HH) ϭ 9.2 Hz, 1 H, one H of RhCH2], 2.14
(s, 3 H, SCCH3), 1.34 [dd, J(RhH) ϭ 0.7, J(PH) ϭ 11.1 Hz, 9 H,
yield 58 mg (73%); m. p. 137°C (dec.) Ϫ IR (C6H6): ν˜ ϭ 1665 cmϪ1
[ν(CϭO)]. Ϫ 1H NMR (200 MHz, C6D6): δ ϭ 3.60 [ddd, J(RhH) ϭ
Eur. J. Inorg. Chem. 1998, 1605Ϫ1617
1615

H. Werner, M. Steinmetz, K. Peters, H. G. von Schnering
FULL PAPER
2.4, J(PH) ϭ 5.0, J(HH) ϭ 8.2 Hz, 1 H, one H of RhCH2], 3.17 408 (52) [Mϩ], 362 (100) [Mϩ Ϫ CH2S], 238 (40) [C5Me5Rhϩ].
[ddd, J(RhH) ϭ J(PH) ϭ 4.1 Hz, J(HH) ϭ 8.2 Hz, 1 H, one H of Ϫ C14H26O3PRhS (408.3): calcd. C 41.18, H 6.42; found C 41.50,
RhCH2], 2.19 (s, 3 H, SCCH3), 1.72 [dd, J(RhH) ϭ 0.3, J(PH) ϭ
2.8 Hz, 15 H, C5Me5], 1.30 [dd, J(RhH) ϭ 0.9, J(PH) ϭ 10.1 Hz,
9 H, PMe3]. Ϫ 13C NMR (22.5 MHz, C6D6): δ ϭ 198.7 (s, CϭO),
98.8 [dd, J(RhC) ϭ 5.2, J(PC) ϭ 3.7 Hz, C5Me5], 29.6 (s, SCCH3),
17.4 [d, J(PC) ϭ 32.4 Hz, PMe3], 10.0 [br. s, C5(CH3)5], 5.9 [dd,
J(RhC) ϭ 28.7, J(PC) ϭ 15.4, RhCH2]. Ϫ 31P NMR (36.2 MHz,
C6D6): δ ϭ 2.1 [d, J(RhP) ϭ 140.1 Hz]. Ϫ MS (70 eV); m/z (%) ϭ
H 6.55.
35. Preparation of [ ( η5-C5Me5) Rh( η2-CH2S) ( PMe3) ] (47):
Compound 47 was prepared analogously to 46 either by using 68.1
mg (0.15 mmol) of 44 and 90 µl of a 1.6  solution (0.15 mmol)
of nBuLi in hexane or 78.4 mg (0.14 mmol) of 49 and ca. 50 mg
of NaOCH3 as starting materials. Orange-brown microcrystalline
solid; yield 41 mg (76%) from 44 and 34 mg (68%) from 49 as
starting material; m. p. 81°C (dec.). Ϫ 1H NMR (200 MHz, C6D6):
δ ϭ 3.87 (m, 2 H, CH2S), 1.87 [dd, J(RhH) ϭ 0.5, J(PH) ϭ 2.4
Hz, 15 H, C5Me5], 1.07 [dd, J(RhH) ϭ 0.9, J(PH) ϭ 9.0 Hz, 9 H,
PMe3]. Ϫ 13C NMR (50.3 MHz, C6D6): δ ϭ 96.6 [dd, J(RhC) ϭ
J(PC) ϭ 4.4 Hz, C5Me5], 46.6 [dd, J(RhC) ϭ 19.9, J(PC) ϭ 5.5
Hz, CH2S], 15.9 [d, J(PC) ϭ 28.5 Hz, PMe3], 10.1 [s, C5(CH3)5]. Ϫ
31P NMR (36.2 MHz, C6D6): δ ϭ 4.9 [d, J(RhP) ϭ 184.6 Hz]. Ϫ
MS (70 eV); m/z (%) ϭ 360 (55) [Mϩ], 314 (100) [Mϩ Ϫ CH2S],
238 (21) [C5Me5Rhϩ]. Ϫ C14H26PRhS (360.3): calcd. C 46.67, H
7.27; found C 46.48, H 7.52.
441 (93) [Mϩ Ϫ CH2SAc], 365 (100) [C5Me5RhIϩ], 314 (7) [Mϩ
Ϫ
CH2SAc Ϫ I], 238 (8) [C5Me5Rhϩ]. Ϫ C16H29IOPRhS (530.3):
calcd. C 36.24, H 5.51; found C 35.83, H 5.53.
33. Preparation of [ ( η5-C5Me5) Rh( CH2SAc) ( PMe3) SAc] (45):
a) A solution of 131.2 mg (0.25 mmol) of 42 in 2 ml of benzene
was treated with a solution of 98.5 mg (0.86 mmol) of KSAc in 1
ml of ethanol and stirred for 30 min at room temp. The solvent
was removed, the residue was extracted with 10 ml of ether and the
extract was concentrated to ca. 1 ml in vacuo. Upon addition of 2
ml of pentane, the solution was stored for 12 h at Ϫ78°C. Yellow
crystals precipitated which were separated from the mother liquor
and dried; yield 80 mg (67%). Ϫ b) A solution of 56.6 mg (0.10
mmol) of 44 in 1 ml of benzene was treated with a solution of 12.2
mg (0.11 mmol) of KSAc in 0.5 ml of ethanol. After the reaction
mixture was worked up as described for a), a yellow solid was ob-
tained; yield 28 mg (58%); m. p. 163°C (dec.). Ϫ IR (C6H6): ν˜ ϭ
1660, 1609 cmϪ1 [ν(CϭO)]. Ϫ 1H NMR (200 MHz, C6D6): δ ϭ
2.70 [ddd, J(RhH) ϭ 2.5, J(PH) ϭ 7.2, J(HH) ϭ 8.5 Hz, 1 H, one
H of RhCH2], 2.55, 2.15 (both s, 3 H each, SCCH3), 1.63 [dd,
J(RhH) ϭ 0.3, J(PH) ϭ 2.9 Hz, 15 H, C5Me5], 1.24 [dd, J(RhH) ϭ
0.9, J(PH) ϭ 10.2 Hz, 9 H, PMe3], signal of one H of RhCH2 not
exactly located. Ϫ 31P NMR (36.2 MHz, C6D6): δ ϭ 2.2 [d,
J(RhP) ϭ 140.0 Hz]. Ϫ MS (70 eV); m/z (%) ϭ 478 (0.1) [Mϩ],
389 (44) [Mϩ Ϫ CH2SAc], 313 (88) [C5Me5Rh(SAc)ϩ], 314 (22)
[C5Me5Rh(PMe3)ϩ], 238 (13) [C5Me5Rhϩ]. Ϫ C18H32O2PRhS2
(478.5): calcd. C 45.19, H 6.74; found C 45.35, H 6.46.
36. Preparation of [ ( η5-C5Me5) Rh{κ2-C,O-CH2SC( Me) O}-
{P( OMe) 3}] PF6 (48): Compound 48 was prepared analogously to
19 by using 130.0 mg (0.22 mmol) of 43 and 56.5 mg (0.22 mmol)
of AgPF6 as starting materials. Orange-yellow solid; yield 117 mg
(89%); dec. temp. 69°C. Ϫ Λ ϭ 82 cm2ΩϪ1molϪ1. Ϫ IR (nujol):
1
ν ϭ 1565 cmϪ1 [ν(CϭO)]. Ϫ H NMR (60 MHz, (CD3)2CO): δ ϭ
˜
3.83 [d, J(PH) ϭ 11.6 Hz, 9 H, P(OMe)3], 3.37 (m, 2 H, RhCH2),
2.40 (s, 3 H, SCCH3), 1.77 [dd, J(RhH) ϭ 0.3, J(PH) ϭ 4.5 Hz, 15
H, C5Me5]. Ϫ 13C NMR (22.5 MHz, CD3NO2): δ ϭ 226.4 (s, Cϭ
O), 103.0 [dd, J(RhC) ϭ 5.9, J(PC) ϭ 4.2 Hz, C5Me5], 54.0 [d,
J(PC) ϭ 5.9 Hz, P(OMe)3], 27.1 [s, C(O)CH3], 21.5 [dd, J(RhC) ϭ
27.9, J(PC) ϭ 22.8 Hz, RhCH2], 9.2 [d, J(RhC) ϭ 2.2 Hz,
C5(CH3)5]. Ϫ 31P NMR (36.2 MHz, CD3NO2): δ ϭ 126.7 [d,
J(RhP) ϭ 251.6 Hz]. Ϫ C16H29F6O4P2RhS (596.3): calcd. C 32.23,
H 4.90; found C 32.10, H 5.11.
37. Preparation of [ ( η5-C5Me5) Rh{κ2-C,O-CH2SC( Me) O}-
( PMe3) ] PF6 (49): Compound 49 was prepared analogously to 19
by using 159.4 mg (0.30 mmol) of 44 and 78.2 mg (0.31 mmol) of
AgPF6 as starting materials. Orange-yellow solid; yield 54 mg
(96%); dec. temp. 96°C. Ϫ Λ ϭ 73 cm2ΩϪ1molϪ1. Ϫ IR (nujol):
ν˜ ϭ 1552 cmϪ1 [ν(CϭO)]. Ϫ 1H NMR (200 MHz, (CD3)2CO): δ ϭ
3.29 [ddd, J(RhH) ϭ 2.9, J(PH) ϭ 0.3, J(HH) ϭ 9.5 Hz, 1 H, one
H of RhCH2], 3.07 [ddd, J(RhH) ϭ 9.5, J(PH) ϭ 18.9 J(HH) ϭ
9.5 Hz, 1 H, on H of RhCH2], 2.36 (s, 3 H, SCCH3), 1.71 [dd,
J(RhH) ϭ 0.3, J(PH) ϭ 2.7 Hz, 15 H, C5Me5], 1.52 [dd, J(RhH) ϭ
0.7, J(PH) ϭ 10.5 Hz, 9 H, PMe3]. Ϫ 13C NMR (22.5 MHz,
CD3NO2): δ ϭ 226.1 (s, CϭO), 100.8 [dd, J(RhC) ϭ 5.9, J(PC) ϭ
2.9 Hz, C5Me5], 27.3 [s, C(O)CH3], 21.7 [dd, J(RhC) ϭ 30.2,
J(PC) ϭ 15.4 Hz, RhCH2], 13.6 [d, J(RhC) ϭ 30.9 Hz, PMe3], 9.3
[br. s, C5(CH3)5]. Ϫ 31P NMR (36.2 MHz, CD3NO2): δ ϭ 4.0 [d,
J(RhP) ϭ 156.3 Hz]. Ϫ C16H29F6OP2RhS (548.3): calcd. C 35.05,
H 5.33; found C 34.66, H 5.45.
34. Preparation of [ ( η5-C5Me5) Rh( η2-CH2S) {P( OMe) 3}] (46):
a) A solution of 81.7 mg (0.14 mmol) of 43 in 8 ml of benzene was
treated with 85 µl of a 1.6  solution (0.14 mmol) of nBuLi in
hexane and stirred for 10 min at room temp. The solvent was re-
moved and the residue was extracted with 10 ml of pentane. The
extract was brought to dryness in vacuo, the oily residue was dis-
solved in 2 ml of benzene and the solution was chromatographed
on Al2O3 (neutral, activity grade IV, height of column 5 cm). With
benzene, an orange fraction was eluted from which the solvent was
removed. The oily residue was dissolved in 8 ml of pentane, the
solution was filtered, the filtrate was concentrated to ca. 2 ml and
then stored for 12 h at Ϫ78°C. Orange-yellow crystals precipitated
which were separated from the mother liquor and dried; yield 42
mg (75%). Ϫ b) A solution of 85.7 mg (0.14 mmol) of 48 in 5 ml
of methanol was treated at room temp. with an excess (ca. 50 mg)
of NaOCH3. After the reaction mixture was stirred for 10 min, the
solvent was removed and the residue was extracted with 15 ml of
pentane. The extract was concentrated to ca. 2 ml in vacuo and
then stored for 12 h at Ϫ78°C. Orange-yellow crystals; yield 42 mg
38. Preparation of [ ( η5-C5H5) Rh( η2-CH2S) ( PMe3) ] (50): Com-
pound 50 was prepared analogously to 46 by using 68.1 mg (0.15
mmol) of 38 and 90 µl of a 1.6  solution (0.15 mmol) of nBuLi
in hexane as starting materials. The yellow microcrystalline solid
50 was identified by comparison of the NMR spectroscopic data
with those of an authentic sample;[1d] yield 34 mg (79%).
1
(73%); m. p. 76°C (dec.). Ϫ H NMR (90 MHz, C6D6): δ ϭ 3.91
[ddd, J(RhH) ϭ 2.7, J(PH) ϭ 0.9, J(HH) ϭ 8.6 Hz, 1 H, one H
of CH2S], 3.34 [d, J(PH) ϭ 12.0 Hz, 9 H, P(OMe)3], 1.77 [dd,
J(RhH) ϭ 0.7, J(PH) ϭ 3.9 Hz, 15 H, C5Me5], signal of one H of
CH2S partly covered by signal of P(OMe)3. Ϫ 13C NMR (50.3
MHz, C6D6): δ ϭ 98.5 [dd, J(RhC) ϭ J(PC) ϭ 4.5 Hz, C5Me5],
51.5 [d, J(PC) ϭ 6.3 Hz, P(OMe)3], 49.5 [dd, J(RhC) ϭ 18.9,
J(PC) ϭ 7.4 Hz, CH2S], 9.7 [s, C5(CH3)5]. Ϫ 31P NMR (36.2 MHz,
C6D6): δ ϭ 143.4 [d, J(RhP) ϭ 290.3 Hz]. Ϫ MS (70 eV); m/z (%) ϭ
39. X-ray Structure Determination of Compound 27[34]: Single
crystals of 27 were grown by slow diffusion of ether to a solution
of 27 in nitromethane at room temp. Crystal data: orthorhombic,
˚
space group Pbca, a ϭ 16.857(5), b ϭ 23.538(6), c ϭ 11.048(3) A,
Z ϭ 8, dcalcd. ϭ 1.613 g cmϪ3, µ(Mo-Kα) ϭ 0.98 mmϪ1; crystal size
1616
Eur. J. Inorg. Chem. 1998, 1605Ϫ1617

A Novel Route to Formaldehyde and Thioformaldehyde Rhodium Complexes
FULL PAPER
A. D. Selmeczy, W. D. Jones, M. G. Partridge, R. N. Perutz,
0.9 ϫ 1.35 ϫ 0.2 mm; Nicolet P3 diffractometer, Mo-Kα radiation,
graphite monochromator; ω scan, 2Θmax ϭ 55°; 4276 reflections
scanned, 4053 unique reflections, 3919 reflections with F > 3σ(F).
Intensity data were corrected for Lorentz and polarization effects
and a geometrical absorption correction was applied. The structure
was solved by the Patterson method. Atomic coordinates and the
anisotropic thermal parameters of the non-hydrogen atoms were
refined by full-matrix least- squares. The positions of all hydrogen
atoms were calculated according to ideal geometry (distance
Organometallics 1994, 13, 522Ϫ532.
[17] [17a]
H. Werner, J. Wolf, U. Schubert, Chem. Ber. 1983, 116,
2848Ϫ2854. Ϫ [17b] H. Werner, L. Hofmann, W. Paul, U. Schub-
ert, Organometallics 1988, 7, 1106Ϫ1111.
[18]
[19]
M. Hesse, H. Meier, B. Zeeh, Spektroskopische Methoden der
organischen Chemie, 2. Ed., Thieme, Stuttgart 1984, p. 144
and 183.
W. E. Buhro, S. Georgiou, J. M. Fernandez, A. T. Patton, C. E.
Strouse, J. A. Gladysz, Organometallics 1986, 5, 956Ϫ965.
[20] [20a]
G. Erker, U. Hoffmann, R. Zwettler, P. Betz, C. Krüger,
Angew. Chem. 1989, 101, 644Ϫ645; Angew. Chem. Int. Ed. Engl.
˚
CϪH ϭ 0.95 A). R ϭ 0.065 , Rw ϭ 0.070 [weighting scheme 1/
1989, 28, 630Ϫ631. Ϫ [20b] G. Erker, F. Sosna, U. Hoffmann, J.
σ2(F)]; reflections-to-parameter ratio 16.00; residual electron den-
[20c]
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Crystallographic data (excluding structure factors) for the struc-
ture reported in this paper have been deposited with the Cam-
bridge Crystallographic Data Centre as supplementary publi-
cation no. CCDC-101821. Copies of the data can be obtained
free of charge on application to the Director, CCDC, 12 Union
Road, Cambridge CB2 1EZ, UK [fax: (internat.)
ϩ44(1223)336Ϫ033; e-mail: deposit@chemcrys.cam.ac.uk].
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1617