Different transmetallation behaviour of [M(P4HR4)] salts toward rhodium(I) and copper(I) (M = Na, K; R = Ph, Mes; Mes = 2,4,6-Me3C6H2)

Article abstract of DOI:10.1039/b718727k

[K₂(P₄Mes₄)] (1) or [Na ₂(THF)₄(P₄Mes₄)] (2) (Mes = 2,4,6-Me₃C₆H₂) reacts with one equivalent of HCl and subsequently with 0.5 equivalents of [{RhCl(cod)}₂] (cod = 1,5-cyclooctadiene) to give a mixture of rhodium complexes, from which [Rh(P₄HMes₄)(cod)] (3) and the secondary product [Rh ₂(μ-P₂HMes₂)(μ-PHMes)(cod)₂] (4) were isolated and characterised by X-ray diffraction studies. Alternatively, the reaction of [K₂(P₄Ph₄)] (5) or [Na ₂(THF)₅(P₄Ph₄)] (6) with one equivalent of HCl and subsequently with one equivalent of [CuCl(PCyp ₃)₂] (Cyp = cyclo-C₅H₉) gave the complex [Cu₄(P₄Ph₄)₂(PH ₂Ph)₂(PCyp₃)₂] (7), presumably via disproportionation of the monoanion (P₄HPh₄)^-. The Royal Society of Chemistry.

Full text of DOI:10.1039/b718727k

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An international journal of inorganic chemistry
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Number 15 | 21 April 2008 | Pages 1945–2068
ISSN 1477-9226
PAPER
Hey-Hawkins et al.
PERSPECTIVE
Different transmetallation behaviour
of [M(P4HR4)] salts toward rhodium(i)
and copper(i)
Le Floch et al.
Bis phosphorus stabilised carbene
complexes
1477-9226(2008)15;1-5

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PAPER
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Different transmetallation behaviour of [M(P4HR4)] salts toward rhodium(I)
and copper(I) (M = Na, K; R = Ph, Mes; Mes = 2,4,6-Me3C6H2)†
Santiago Go´mez-Ruiz, Robert Wolf and Evamarie Hey-Hawkins*
Received 4th December 2007, Accepted 31st January 2008
First published as an Advance Article on the web 27th February 2008
DOI: 10.1039/b718727k
[K2(P4Mes4)] (1) or [Na2(THF)4(P4Mes4)] (2) (Mes = 2,4,6-Me3C6H2) reacts with one equivalent of HCl
and subsequently with 0.5 equivalents of [{RhCl(cod)}2] (cod = 1,5-cyclooctadiene) to give a mixture
of rhodium complexes, from which [Rh(P4HMes4)(cod)] (3) and the secondary product
[Rh2(l-P2HMes2)(l-PHMes)(cod)2] (4) were isolated and characterised by X-ray diffraction studies.
Alternatively, the reaction of [K2(P4Ph4)] (5) or [Na2(THF)5(P4Ph4)] (6) with one equivalent of HCl and
subsequently with one equivalent of [CuCl(PCyp3)2] (Cyp = cyclo-C5H9) gave the complex
[Cu4(P4Ph4)2(PH2Ph)2(PCyp3)2] (7), presumably via disproportionation of the monoanion (P4HPh4)−.
anions might be complicated by their instability in solution.8 To
Introduction
evaluate this hypothesis, we studied transmetallation reactions of
the monoanions (P4HR4)− (M = Na, K; R = Ph, Mes) towards a
The chemistry of phosphorus-rich compounds is of much current
interest, due to their similarities and differences to isolobal
carbon counterparts.1 In this context, there has been renewed
variety of metal salts, and we now report the results of the reactions
with rhodium(I) and copper(I) halides.
interest in alkali metal oligophosphanides M{cyclo-(PnRn–1)} (n =
3–5) and M2(PnRn) (n = 2–4; M = Li, Na, K).2 Only recently
Results and discussion
have the interesting structural properties of these anions been
fully unravelled, and their reactivity towards metals in different
[K2(P4Mes4)] (1) or [Na2(THF)4(P4Mes4)] (2) reacts with one
oxidation states explored.3–7 Our initial efforts focussed on the
equivalent of HCl in polar solvents such as THF or diethyl ether,
targeted, high-yield synthesis of [Na{cyclo-(P5tBu4)}],4a,6a its
and the (P4HR4)− anion formed “in situ” was then treated with
coordination and main group chemistry6,7 and the preparation
half an equivalent of [{RhCl(cod)}2] (cod = 1,5-cyclooctadiene)
and reactivity of (P4R4)2− dianions (R = alkyl or aryl).4a–c,5
to give a mixture of products, from which two rhodium-containing
In contrast, the chemistry of the monoprotonated anions
complexes could be isolated by repeated crystallization from
THF (Scheme 1). The more soluble component of this mixture
(PnHRn)− (n = 2–4)4e,8,9 has remained almost unexplored.
10
Prior to this report, only [K(pmdeta)(P2HtBu2)]2 [pmdeta =
was identified as [Rh(P4HMes4)(cod)] (3), and the other product
11
MeN(CH2CH2NMe2)2] and [Li(thf)(P2HPh2)]4 were isolated in
as [Rh2(l-P2HMes2)(l-PHMes)(cod)2] (4). Complex 4 could be
pure form, while the potassium salts [K(crypt)][P2HPh2]4b (crypt =
isolated as a pure compound, albeit as mixture of diastereomers
because of the presence of chiral phosphorus centres, while
3 was always contaminated with a very small quantity of 4.
Compounds 3 and 4 were characterised by IR and multinuclear
NMR spectroscopy, mass spectrometry and X-ray diffraction
studies.
2,2,2-cryptand) and [{K(pmdeta)(P3HMes3)}2{K2(P4Mes4)}]
(Mes
=
2,4,6-Me3C6H2)4e and the related CuI complexes
[Cu2(P2HMes2)2(PCyp3)2] and [Cu5Cl(P2HMes2)3(PHMes)(PC-
yp3)2] (Cyp = cyclo-C5H9) were only obtained in product mixtures
and mainly characterised by X-ray diffraction studies.4c Moreover,
the molybdenum complex [Cp◦MoCl2(P4HCy4)] (Cp◦ = C5Me4Et)
containing the tetraphosphanide anion (P4HCy4)− was obtained
in very low yield from the deprotonation of [Cp◦MoCl4(PH2Cy)]
with NEt3, but the mechanism of its formation has remained
unclear.12
Complexes 3 and 4 show very complicated 1H NMR spectra due
to the asymmetry of the molecules and the presence of a mixture
of isomers. The signals corresponding to the methyl groups of the
mesityl moieties (some of which are slightly broadened) appear
as singlets between 1.5 and 3.2 ppm, and the aromatic protons of
the mesityl groups in the region between 6.4 and 6.9 ppm. The
alkyl protons of the cod ligand could not be detected, probably
due to overlap with the methyl signals of the mesityl substituents.
Nevertheless, the olefinic protons of cod were observed as broad
signals between 3.6 and 4.4 ppm. The P–H protons also appear as
broad signals, between 3.6 and 6.3 ppm.
Recently, we reported the targeted synthesis and unusual struc-
tural properties of the (P4HMes4)− anion, which partially dispro-
portionates in solution and exhibits fluxional behaviour of its P–H
proton. Possible synthetic applications of such tetraphosphanide
Institut fu¨r Anorganische Chemie der Universita¨t Leipzig, Johannisallee 29,
04103 Leipzig, Germany. E-mail: hey@rz.uni-leipzig.de; Fax: (+49)341-
9739319
1
The high-resolution 31P{ H} NMR spectrum of the reaction
mixture shows eight multiplets, four corresponding to 3 at ca.
38, −23, −35 and −61 ppm (ABCDX spin system) and four
corresponding to the mixture of isomers of 4 at ca. 26, 10, −4 and
−86 ppm (two ABCXY spin systems). Some additional, minor
signals appeared when the mixture was stirred for a prolonged
† Electronic supplementary information (ESI) available: 1: Simulated and
experimental 31P NMR spectrum of [Rh(P4HMes4)(cod)] (3). 2: Variable-
1
temperature 31P{ H} NMR spectra of [Rh2(l-P2HMes2)(l-PHMes)(cod)2]
(4). CCDC reference numbers 666346 (3), 666347 (4) and 666348 (7) see
DOI: 10.1039/b718727k
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Scheme 1
period and coincide with those observed in the reaction mixture
of one equivalent of [{RhCl(cod)}2] with one equivalent of 1. In
the proton-coupled 31P NMR spectrum of 3 one of the signals
(PB) is further split by coupling to hydrogen, an ABCDXY
spin system is observed and the 31P NMR parameters could be
obtained via simulation using the program SPINWORKS13 (see
experimental section and electronic supplementary information
for details). The 1JPP (167.55–272.71 Hz) and 2JPP (16.54–57.96 Hz)
1
coupling constants are in the expected ranges and the JRhP
coupling constants (85.32 and 160.60 Hz) are of the same
order of magnitude as, for example, observed for the related
complex [Rh{cyclo-(P5tBu4)}(PPh3)2].6b In addition, a very large
1JPH coupling constant (335.24 Hz) unequivocally supports the
1
presence of a P–H proton at PB. Attempts to simulate the 31P{ H}
NMR spectrum of 4 failed due to the severe overlap of signals
from two different isomers which presumably contain the two P–
H protons in mutual cis and trans arrangements.
Fig. 1 Molecular structure and atom labelling scheme for 3 with thermal
ellipsoids at 50% probability (hydrogen atoms, except at phosphorus, are
omitted for clarity).
¯
Complex 3 crystallises as orange plates in the space group P1
with two molecules in the unit cell. The X-ray crystal structure
determination reveals that the rhodium atom has a distorted
4
square-planar geometry in which a cod ligand is g coordinated
and the (P4HR4)− ligand chelates the metal centre via its two
terminal phosphorus atoms (P1 and P4, Fig. 1). Selected bond
lengths and angles are given in Table 1. Similar to the structure
of [Rh{cyclo-(P5tBu4)}(PPh3)2],6b the Rh(1)–P(1) bond length in 3
is 229.89(8) pm, while the Rh(1)–P(4) distance of 225.66(9) pm is
somewhat shorter, as it corresponds to a coordinated phosphane.
The P–P distances [219.9(1)–222.3(1) pm] indicate single bonds.14
The P4 chain is in a syn arrangement (torsion angle P(1)–P(2)–
P(3)–P(4) −44.3◦) and is clearly unsymmetrical, with the proton
bound to the terminal phosphorus atom P(4) [P(4)–H(4P) 126(3)
pm, the position of this proton was located from the Fourier
difference map and refined freely]. The four phosphorus atoms
are significantly pyramidalised and form a five-membered ring
with the rhodium atom, which is in an envelope conformation
with P(2) deviating by −45.6 pm from the mean plane formed by
Rh(1)–P(1)–P(3)–P(4).
Complex 4 crystallises as very thin orange plates in the space
¯
group P1 with two molecules of 4 and two THF molecules in
the unit cell. Both rhodium atoms have a distorted square-planar
4
geometry with one g -coordinated cod ligand at each rhodium
atom and bridging (P2HMes2)− and PHMes− anions (Fig. 2). The
Rh(1)–P(1) and Rh(2)–P(2) bond lengths [228.8(2) and 228.8(2)
pm] are similar to those of 3, while the Rh(1)–P(3) and Rh(2)–P(3)
distances [237.1(2) and 237.2(2) pm] are significantly longer. The
P(1)–P(2) bond length of 216.8(2) pm is typical for complexes
containing (P2HR2)− anions.4b,c,10,11 The positions of the P–H
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Table 1 Selected bond lengths (pm) and angles (◦) for 3 and 4
could be the disproportionation of two equivalents of the “in situ”-
generated (P4HPh4)− monoanion before or after the transmetalla-
tion step to give one equivalent of (P4Ph4)2− and one equivalent of
P4H2Ph4. The latter is very unstable in solution and decomposes
rapidly to give a mixture of the phosphanes cyclo-(PnPhn), P2H2Ph2
and PH2Ph,15 the last-named of which is found as a ligand in 7.
Nevertheless, an alternative metal-mediated mechanism cannot be
discounted.
The complex crystallises in the centrosymmetric space group
P21/c and selected bond lengths and angles are given in Table 2.
Its molecular structure (Fig. 3) is similar to that of the previously
reported [Cu4(P4Ph4)2(PCyp3)3], which was obtained from the
reaction of two equivalents of [CuCl(PCyp3)2] with one equivalent
of 6,5a with the difference that instead of a third PCyp3 ligand two
PH2Ph ligands are present in 7. This leads to a centrosymmetric
arrangement of the Cu4P8 cluster core which differs significantly
from that in [Cu4(P4Ph4)2(PCyp3)3] (Fig. 4).
3
4
Rh(1)–P(1)
Rh(1)–P(3)
Rh(1)–P(4)
Rh(2)–P(2)
Rh(2)–P(3)
P(1)–P(2)
229.89(8)
225.66(9)
228.8(2)
237.1(2)
228.8(2)
237.2(2)
216.8(2)
222.3(1)
221.2(1)
219.9(1)
P(2)–P(3)
P(3)–P(4)
P(2)–H(2P)
P(3)–H(3P)
P(4)–H(4P)
111(7)
126(6)
126(3)
P(1)–P(2)–P(3)
P(2)–P(3)–P(4)
95.91(4)
96.80(4)
113.75(4)
119.48(4)
88.16(3)
Rh(1)–P(1)–P(2)
Rh(1)–P(4)–P(3)
P(1)–Rh(1)–P(4)
P(1)–Rh(1)–P(3)
P(2)–Rh(2)–P(3)
Rh(2)–P(2)–P(1)
Rh(1)–P(3)–Rh(2)
113.13(9)
87.67(6)
84.76(6)
115.72(9)
128.31(8)
Fig. 3 Molecular structure and atom labelling scheme for 7 with thermal
ellipsoids at 50% probability (hydrogen atoms, except at phosphorus, and
labels for carbon atoms are omitted for clarity). Symmetry transformation
to generate equivalent atoms: 2 − x, y, 1 − z.
Fig. 2 Molecular structure and atom labelling scheme for 4 with thermal
ellipsoids at 50% probability (hydrogen atoms, except at phosphorus, are
omitted for clarity).
Table 2 Selected bond lengths (pm) and angles (◦) for 7a
protons were located from the Fourier difference map, and their
free refinement yielded reasonable P(2)–H(2P) and P(3)–H(3P)
distances of 111(7) and 126(6) pm, respectively.
Cu(1)–P(1)
Cu(1)–P(4)
Cu(1)–P(5)
Cu(2)–P(1)ꢀ
Cu(2)–P(4)
Cu(2)–P(6)
230.1(1)
P(1)–P(2)
P(2)–P(3)
P(3)–P(4)
P(5)–H(1p)
P(5)–H(2p)
218.6(1)
220.5(1)
218.6(1)
130(3)
233.38(8)
222.72(8)
227.56(8)
228.47(8)
222.64(9)
In the FAB mass spectrum of 3 the molecular ion peak and
characteristic fragments such as [M − cod]+, [M − cod − PHMes]+
and [M − cod − P2HMes2]+ (100.0%) were observed. Similar
fragments were also observed for 4 in addition to the molecular
ion peak and, interestingly, the organyl-free fragments [Rh2P3]+
and [Rh2P2]+. The P–H stretching frequencies were observed in
the expected region at ca. 2360 cm−1 in the IR spectrum of 3
and 4.
The complex [Cu4(P4Ph4)2(PH2Ph)2(PCyp3)2] (7) was obtained
from the reaction of one equivalent of [K2(P4Ph4)] (5) or
[Na2(THF)5(P4Ph4)] (6) with one equivalent of HCl followed
by subsequent reaction with one equivalent of [CuCl(PCyp3)2]
(Scheme 1). The desired (P4HPh4)− anion is not present in 7.
Instead, two (P4Ph4)2− dianions are coordinated to four copper(I)
cations. One of the possible explanations for this phenomenon
130(3)
P(6)–Cu(2)–P(1)ꢀ
P(6)–Cu(2)–P(4)
P(1)ꢀ–Cu(2)–P(4)
P(5)–Cu(1)–P(1)
P(5)–Cu(1)–P(2)ꢀ
P(1)–Cu(1)–P(2)ꢀ
P(5)–Cu(1)–P(4)
P(1)–Cu(1)–P(4)
P(2)ꢀ–Cu(1)–P(4)
P(4)–P(3)–P(2)
127.39(3)
133.20(3)
99.31(3)
124.13(3)
108.74(3)
108.03(2)
106.14(3)
107.02(3)
100.15(2)
95.54(4)
P(3)–P(4)–Cu(1)
Cu(2)–P(4)–Cu(1)
P(1)–P(2)–P(3)
100.25(4)
109.73(3)
101.46(3)
105.23(3)
125.35(4)
104.09(3)
90.31(3)
116.31(3)
113(2)
P(1)–P(2)–Cu(1)ꢀ
P(3)–P(2)–Cu(1)ꢀ
P(2)–P(1)–Cu(2)ꢀ
P(2)–P(1)–Cu(1)
Cu(2)ꢀ–P(1)–Cu(1)
Cu(1)–P(5)–H(1P)
Cu(1)–P(5)–H(2P)
H(1P)–P(5)–H(2P)
116(2)
96(2)
P(3)–P(4)–Cu(2)
110.92(3)
a Symmetry transformation to generate equivalent atoms: 2 − x, y, 1 − z.
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PCyp3. The signal corresponding to the protons of the PH2Ph
groups is observed as a broad doublet at ca. 4.4 ppm.
The aromatic protons are observed as broad signals between 6.0
and 7.5 ppm. As observed previously for [Cu4(P4Ph4)2(PCyp3)3],
1
the room-temperature 31P{ H} NMR spectrum is very compli-
cated, displaying broad peaks at 19.9, 11.3, 7.8, −5.0, −9.7, −24.7,
−46.5, −70.3, −79.5 and −94.0 ppm of varying intensity, and it
appears unlikely that the molecular structure of 7 is retained in
solution. The FAB mass spectrum of this complex does not show
the molecular ion peak, but typical fragments for this molecule
derived from the loss of organic substituents (Ph, Cyp) and copper
tricyclopentylphosphane units as well as the fragment [Cu3P8]+
are observed. Finally the IR spectrum shows the typical P–H
stretching bands at 2330 and 2326 cm−1.
Conclusions
While previous attempts to employ M(P4HMes4) salts in trans-
metallation reactions with transition metal halides showed the
presence of (P4HMes4)−-containing complexes in the reaction
mixtures, which could not be separated, the preparation of
the rhodium complex [Rh(P4HMes4)(cod)] (3) now represents
the first targeted synthesis (albeit in low yield) of a transition
metal complex containing a tetraphosphanide anion. Thus, the
(P4HMes4)− anion is apparently stable enough to be transmetal-
lated successfully in spite of its lability in solution.8 However, this
lability leads to the formation of the secondary product [Rh2(l-
P2HMes2)(l-PHMes)(cod)2] (4).
Fig.
4
Comparison of the core structures of
7
(top) and
[Cu4(P4Ph4)2(PCyp3)3] (bottom).
In contrast, the (P4HPh4)− anion did not remain intact in
the attempted transmetallation reaction of M(P4HPh4) with
[CuCl(PCyp3)2]. The complex [Cu4(P4Ph4)2(PH2Ph)2(PCyp3)2] (7)
was obtained instead, which indicates preferred formation of the
[Cu4(P4Ph4)2] entity. This has previously been observed in the
complex [Cu4(P4Ph4)2(PCyp3)3]5a and may thus be a favoured
structural unit for copper(I) tetraphosphanediido complexes. The
difference in reactivity between the M(P4HMes4) and M(P4HPh4)
salts may be attributed to the lower amount of steric shielding
provided by the phenyl substituents in the (P4HPh4)− anion, which
facilitates rearrangement processes. The outcome of transmetalla-
tion reactions of M(P4HR4) salts thus depends on careful tuning of
a number of different parameters, including the substituents of the
(P4HR4)− anion and the type of transition metal halide employed.
From a heuristic viewpoint, the structure of 7 may be viewed
as a “crownlike”, ten-membered [Cu2(P4Ph4)2]2− macrocycle which
coordinates two further copper ions through two terminal phos-
phorus atoms of the same P4 chain and one internal phosphorus
atom of the other P4 chain. Although unusual, such an aggregation
is not completely unprecedented, as other copper(I) phosphanido
compounds generally form four- to eight-membered CunPn rings,
depending on the size of the substituents on phosphorus.16
Two distinct coordination environments can be distinguished for
copper: Cu(1) shows a tetrahedral geometry and Cu(2) is in
a trigonal-planar environment (sum of bond angles at Cu(2):
359.90◦). Both crystallographically independent Cu atoms are
coordinated by two terminal phosphorus atoms from the (P4Ph4)2−
chains. However, Cu(1) is coordinated by two terminal P atoms
from the same P4 chain, giving rise to the formation of five-
membered CuP4 chelate rings, while Cu(2) bridges two terminal
P atoms from different chains. The coordination sphere of Cu(1)
is completed by coordination of an internal phosphorus atom of
the second (P4Ph4)2− ligand and a PH2Ph ligand. Cu(2) is further
coordinated by a PCyp3 ligand.
Experimental
General remarks
All experiments were performed under an atmosphere of dry
argon using standard Schlenk techniques. The NMR spectra were
recorded on a Bruker AVANCE DRX 400 spectrometer. 1H NMR
(400.13 MHz): internal standard solvent, external standard TMS;
31P NMR (161.9 MHz): external standard 85% H3PO4; IR spectra:
KBr pellets were prepared in a nitrogen-filled glove box and the
spectra were recorded on a Perkin-Elmer System 2000 FTIR
spectrometer in the range 350–4000 cm−1. FAB-MS spectra were
recorded in a MASPEC II spectrometer with 3-nitrobenzyl alcohol
as matrix. All solvents were purified by distillation, dried, saturated
with argon and stored over potassium mirror. [{RhCl(cod)}2],17
[CuCl(PCyp3)2],5a K2(P4Mes4) (1), Na2(P4Mes4) (2), K2(P4Ph4) (5)
The P–P bond lengths range from 218.6(2) to 220.5(1) pm and
are in the expected range for single bonds.14 The P4 chains of the
(P4Ph4)2− ligands are in a syn arrangement and display rather large
torsion angles as a consequence of the coordination of an internal
phosphorus atom to one copper atom in each of the ligands (P(1)–
P(2)–P(3)–P(4) 67.53, cf . P(1)–P(2)–P(2)ꢀ–P(1)ꢀ 32.18◦ in 6).4a
1
The H NMR spectrum of 7 is similar to that reported for
[Cu4(P4Ph4)2(PCyp3)3] and shows three broad signals between 1.0
and 2.0 ppm corresponding to the cyclopentyl groups of the
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and Na2(P4Ph4) (6)4a,c,e,i were synthesised according to literature
procedures. Simulation of the 31P NMR spectrum of 3 was carried
out using the program SPINWORKS.13
obtained from this solution, which were isolated by filtration and
identified as 4. The filtrate was evaporated in vacuum and the
resulting solid analysed and identified as 3◦. Yield of 3: 0.15 g (26%);
mp 111–113 ◦C; 1H NMR ([D8]THF, 25 C, for the predominant
isomer): d 1.63 (6H), 1.97 (6H), 2.01 (12H), 2.98 (6H), 3.03 (6H)
(br s, Me of Mes), 3.75 (1H), 3.99 (2H), 4.37 (1H) (br, CH of
cod), 4.4–6.3 (several broad signals, P–H), 6.45 (3H), 6.56 (1H),
6.72 (1H), 6.80 (3H), (s, aromatic CH of Mes), CH2 of cod
Data collection and structural refinement of 3, 4 and 7. The
data of 3, 4 and 7 were collected on a CCD Oxford Xcalibur
˚
S diffractometer (k(Mo-Ka) = 0.71073 A) using x and φ scan
mode. Semi-empirical from equivalents absorption corrections
were carried out with SCALE3 ABSPACK18 and the structures
were solved with direct methods.19
obscured by other signals; 13C{ H} NMR ([D8]THF, 25 ◦C, for
1
the predominant isomer): d 19.6, 19.9 (br s, p-Me in Mes), 21.0,
21.6 (br s, p-Me in Mes), 27.1, 27.4, 27.6, 27.8 (s, o-Me in Mes),
29.8, 30.1, 30.2, 30.8, 31.2, 32.3, 32.4 (s, o-Me in Mes and CH of
cod), 80.7, 85.5, 90.7, 93.3 (br s, CH of cod), 127.4, 127.6, 127.7,
128.1, 128.3, 128.5, 128.7 (s, 3,5-C in Mes), 132.3–142.9 (several s,
1,2,4,6-C in Mes); 31P NMR ([D8]THF, 25 ◦C, for the predominant
isomer): d 39.34 (m, PA, 1JAC = 167.55, 1JAX = 85.32, 2JAB = 16.54,
Structure refinement was carried out with SHELXL-97.20 All
non-hydrogen atoms were refined anisotropically, the H atoms
bonded to phosphorus were localised and refined freely and
the other hydrogen atoms were placed in calculated positions
and refined with calculated isotropic displacement parameters.
Crystallographic data for 3, 4 and 7 are presented in Table 3.
CCDC reference numbers 666346 (3), 666347 (4) and 666348
(7).
3
1
2JAD = 57.96, JAY = 5.29 Hz), −23.31 (m, PB, JBD = 272.71,
1JBX = 160.60, 1JBY = 335.24, 2JBC = 55.29), −34.41 (m, PC, 1JCD
=
For crystallographic data in CIF or other electronic format see
DOI: 10.1039/b718727k
205.56), −61.16 (m, PD); FAB-MS, matrix: 3-NBA; m/z (%): 813.3
(42.3) [M + H]+, 812.3 (2.4) [M]+, 704.2 (5.6) [M − cod]+, 553.1
(53.4) [M − cod − PHMes]+, 401.0 (100.0) [M − 2H − cod −
P2HMes2]+; IR (cm−1): 3018 m, 2962 s, 2917 s, 2868 m, 2729 w,
2362 w, 1603 s, 1554 m, 1452 s, 1408 m, 1376 m, 1289 m, 1261 s,
1096 s, 1028 s, 846 s, 805 s, 713 w, 614 m, 554 m, 462 w. Elemental
analysis (%): found (calc. for C44H57P4Rh, M = 812.69): C 64.35
(65.02); H 7.03 (7.07).
Synthesis of [Rh(P4HMes4)(cod)] (3) and [Rh2(l-P2HMes2)(l-
PHMes)(cod)2] (4). A solution of HCl in Et2O (2 M) (0.34 mL,
0.70 mmol) in diethyl ether (10 mL) was carefully added to
an orange solution of K2(P4Mes4) (0.46 g, 0.70 mmol) in THF
(10 mL). A red suspension formed which was allowed to warm to
room temperature slowly over 2 h and stirred for 5 h. The mixture
was filtered and subsequently the filtrate was added carefully to a
solution of [{RhCl(cod)}2] (0.17 g, 0.35 mmol) in THF (40 mL) at
−78 ◦C, and the deep red solution turned brown. The mixture was
stirred for 3 h, and the solvent was removed under vacuum. The
resulting dark brown oil was extracted twice with Et2O (40 mL)
and filtered. The combined extracts were reduced to ca. 15 mL. An
orange solid formed over one week at −30 ◦C, which was isolated
and characterised as a mixture of 3 and 4 (ratio ca. 1 : 3). This
solid was recrystallised from THF (15 mL). Orange crystals were
Yield of 4: 0.10 g (16%); mp 143–148 ◦C; 1H NMR ([D8]THF,
25 ◦C, for the predominant isomer): d 1.67, 1.80, 1.83, 2.01, 2.02,
2.11, 2.41, 2.85, 2.92 (s, each 3H, Me of Mes), 3.62 (2H), 4.15
(4H), 4.27 (2H) (br, CH of cod), 4.70–6.19 (several broad signals,
P-H), 6.42, 6.70, 6.74 (s, each 2H, aromatic CH of Mes), CH2 of
◦
1
cod obscured by other signals; 13C{ H} NMR (THF[D8], 25 C,
for the mixture of isomers): d 20.0, 20.8, 21.2, 21.4, 21.8 (s, p-
Me in Mes), 27.5–27.7 (several s, o-Me in Mes), 29.1, 29.5, 30.0,
30.3, 30.4, 30.5, 31.0, 31.3, 32.2, 32.5 (s, o-Me in Mes and CH
Table 3 Crystallographic data for 3, 4 and 7
3
4
7
Empirical formula
C44H57P4Rh
812.69
C47H67OP3Rh2
946.74
C90H108P12Cu4
1815.56
0.30 × 0.10 × 0.10
Monoclinic
P21/c
1420.8(5)
1853.6(5)
1692.3(5)
90
107.519(5)
90
4.250(2)
2
130(2)
1.419
1.258
M
Crystal dimensions/mm3
0.4 × 0.05 × 0.05
0.50 × 0.02 × 0.01
Crystal system
Space group
Triclinic
Triclinic
¯
¯
P1
P1
a/pm
822.5(2)
1190.2(2)
2153.6(4)
105.21(1)
94.20(1)
92.75(1)
2.0241(6)
2
1262.7(5)
1294.1(5)
1560.4(5)
74.908(5)
84.544(5)
67.189(5)
2.270(2)
2
b/pm
c/pm
a/◦
b/◦
c /◦
V/nm3
Z
T/K
130(2)
1.333
0.610
130(2)
1.386
0.866
Dc/Mg m−3
l/mm−1
F(000)
Reflns collected/unique
Rint
852
38404/9977
0.0568
984
35456/9985
0.0582
1888
99893/9374
0.0592
Data/restraints/parameters
Final R1/wR2 [I > 2r(I)]
Final R1/wR2 (all data)
9977/0/458
0.0430/0.0823
0.0731/0.0843
0.537/−0.496
9985/6/471
0.0495/0.1530
0.0904/0.1728
2.156/−0.866
9374/0/486
0.0306/0.0523
0.0660/0.0786
0.797/−0.564
−3
˚
Dqmax/min/e A
1986 | Dalton Trans., 2008, 1982–1988
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of cod), 81.1, 82.4, 84.3, 85.0, 85.1, 85.8, 85.9, 88.9, 91.0, 92.7,
93.0, 96.2, 97.1, 97.2 (s, CH of cod), 127.0, 128.1, 128.4, 128.6,
129.3, 129.4 (s, 3,5-C in Mes), 133.7, 134.8, 136.0, 136.7, 137.1,
138.0, 138.1, 138.2, 138.4, 140.1, 140.3, 141.5, 142.7, 142.9, 143.0,
Notes and references
1 (a) See, for example: K. B. Dillon, F. Mathey and J. F. Nixon, in
Phosphorus: The Carbon Copy: From Organophosphorus to Phospha-
organic Chemistry, John Wiley and Sons Ltd., Chichester, 1998;
(b) D. A. Pantazis, J. E. McGrady, J. M. Lynam, C. A. Russell and M.
Green, Dalton Trans., 2004, 2080; (c) E. Urnezius, W. W. Brennessel,
C. J. Cramer, J. E. Ellis and P. R. Schleyer, Science, 2002, 295, 832;
(d) J. J. Weigand, N. Burford, M. D. Lumsden and A. Decken, Angew.
Chem., 2006, 118, 6745; J. J. Weigand, N. Burford, M. D. Lumsden and
A. Decken, Angew. Chem., Int. Ed., 2006, 46, 6733.
2 (a) K. Issleib and K. Krech, Chem. Ber., 1965, 98, 2545; (b) K. Issleib
and E. Fluck, Z. Anorg. Allg. Chem., 1965, 339, 274; (c) K. Issleib and
K. Krech, Chem. Ber., 1966, 99, 1310; (d) K. Issleib and M. Hoffmann,
Chem. Ber., 1966, 99, 1320; (e) K. Issleib, Ch. Rockstroh, I. Duchek
and E. Fluck, Z. Anorg. Allg. Chem., 1968, 360, 77; (f) K. Issleib and
K. Krech, J. Prakt. Chem., 1969, 311, 463; (g) M. Baudler, D. Koch, E.
Tolls, K. M. Diederich and B. Kloth, Z. Anorg. Allg. Chem., 1976, 420,
146; (h) P. R. Hoffmann and K. G. Caulton, J. Am. Chem. Soc., 1975,
97, 6370; (i) M. Baudler and D. Koch, Z. Anorg. Allg. Chem., 1976,
425, 227.
◦
144.1, 144.5 (s, 1,2,4,6-C in Mes); 31P{ H} NMR ([D8]THF, 25 C,
for the mixture of isomers): d 26.0 (m), 9.7 (m), −4.5 (m), −86.1
(m); FAB-MS, matrix: 3-NBA; m/z (%): 875.2 (24.7) [M + H]+,
874.2 (2.0) [M]+, 721.1 (5.0) [M − H − PHMes]+, 662.2 (13.6)
[M − Rh − cod]+, 656.0 (6.0) [M − 2H − 2cod]+, 571.0 (39.3)
[M − 2H − P2HMes2]+, 401.0 (100.0) [M − 2H − Rh − cod −
PHMes]+, 298.9 (18.8) [M − 2H − 2cod − 3Mes = Rh2P3]+, 267.7
(22.7) [M − H − PHMes − 2cod − 2Mes = Rh2P2]+; IR (cm−1):
3021 m, 2965 s, 2920 s, 2868 m, 2728 w, 2370 m, 2361 w, 1601 s,
1549 m, 1462 w, 1451 s, 1408 m, 1376 m, 1299 w, 1289 m, 1262 s,
1099 s, 1028 s, 846 s, 802 s, 711 w, 611 m, 555 m, 461 w. Elemental
analysis (%): found (calc. for C43H59P3Rh2, M = 874.66): C 58.66
(59.05); H 6.68 (6.80).
1
3 (a) H. Ko¨pf and R. Voigtla¨nder, Chem. Ber., 1981, 114, 2731; (b) R. A.
Jones, M. H. Seeberger and B. R. Whittlesey, J. Am. Chem. Soc., 1985,
107, 6424; (c) B. Riegel, A. Pfitzner, G. Heckmann, E. Fluck and H.
Binder, Phosphorus, Sulfur, Silicon Relat. Elem., 1994, 93, 173; (d) B.
Riegel, A. Pfitzner, G. Heckmann, H. Binder and E. Fluck, Z. Anorg.
Allg. Chem., 1994, 620, 8; (e) B. Riegel, A. Pfitzner, G. Heckmann, H.
Binder and E. Fluck, Z. Anorg. Allg. Chem., 1995, 621, 1989; (f) D.
Bongert, G. Heckmann, W. Schwarz, H. D. Hausen and H. Binder,
Z. Anorg. Allg. Chem., 1995, 621, 1358; (g) D. Bongert, G. Heckmann,
W. Schwarz, H. D. Hausen and H. Binder, Z. Anorg. Allg. Chem., 1996,
622, 1167; (h) D. Bongert, G. Heckmann, H. D. Hausen, W. Schwarz
and H. Binder, Z. Anorg. Allg. Chem., 1996, 622, 1793; (i) H. Binder, B.
Schuster, W. Schwarz and K. W. Klinkhammer, Z. Anorg. Allg. Chem.,
1999, 625, 699.
4 (a) A. Schisler, Dissertation, Universita¨t Leipzig, 2003; (b) J. Geier,
Dissertation, ETH Zu¨rich, 2004; (c) R. Wolf, Dissertation, Universita¨t
Leipzig, 2005; (d) J. Geier, H. Ru¨egger, M. Wo¨rle and H. Gru¨tzmacher,
Angew. Chem., 2003, 113, 4081; J. Geier, H. Ru¨egger, M. Wo¨rle and
H. Gru¨tzmacher, Angew. Chem., Int. Ed., 2003, 42, 3951; (e) R. Wolf,
A. Schisler, P. Lo¨nnecke, C. Jones and E. Hey-Hawkins, Eur. J. Inorg.
Chem., 2004, 3277; (f) J. Geier, J. Harmer and H. Gru¨tzmacher, Angew.
Chem., 2004, 116, 4185; J. Geier, J. Harmer and H. Gru¨tzmacher,
Angew. Chem., Int. Ed., 2004, 43, 4093; (g) M. Kaupp, A. Patrakov,
R. Reviakine and O. L. Malkina, Chem.–Eur. J., 2005, 11, 2773; (h) R.
Wolf and E. Hey-Hawkins, Z. Anorg. Allg. Chem., 2006, 632, 727;
(i) D. Stein, A. Dransfeld, M. Flock, H. Ru¨egger and H. Gru¨tzmacher,
Eur. J. Inorg. Chem., 2006, 4157.
5 (a) R. Wolf and E. Hey-Hawkins, Angew. Chem., 2005, 117, 6398;
R. Wolf and E. Hey-Hawkins, Angew. Chem., Int. Ed., 2005, 44,
6241; (b) R. Wolf and E. Hey-Hawkins, Eur. J. Inorg. Chem., 2006,
1348; (c) S. Go´mez-Ruiz and E. Hey-Hawkins, Dalton Trans., 2007,
5678.
6 (a) A. Schisler, U. Huniar, P. Lo¨nnecke, R. Ahlrichs and E. Hey-
Hawkins, Angew. Chem., 2001, 113, 4345; A. Schisler, U. Huniar, P.
Lo¨nnecke, R. Ahlrichs and E. Hey-Hawkins, Angew. Chem., Int. Ed.,
2001, 40, 4217; (b) A. Schisler, P. Lo¨nnecke and E. Hey-Hawkins, Inorg.
Chem., 2005, 44, 461; (c) S. Go´mez-Ruiz, A. Schisler, P. Lo¨nnecke and
E. Hey-Hawkins, Chem.–Eur. J., 2007, 13, 7974.
Synthesis of [Cu4(P4Ph4)2(PH2Ph)2(PCyp3)2] (7). A solution
of HCl in Et2O (2 M) (0.68 mL, 1.40 mmol) in THF (25 mL)
was carefully added to a red solution of Na2(P4Ph4) (1.16 g,
1.40 mmol) in THF (30 mL). An orange suspension formed, which
was allowed to warm to room temperature slowly over 2 h and
stirred for 5 h. The mixture was filtered, the filtrate was added
carefully to a solution of [CuCl(PCyp3)2] (0.80 g, 1.40 mmol) in
THF (30 mL) at −78 ◦C and the deep red solution turned brown.
The mixture was stirred for 16 h and the solvent was completely
evaporated. The resulting dark brown oil was extracted twice with
toluene (75 mL) and filtered. The combined filtrates were reduced
to ca. 20 mL. Yellow crystals formed over two weeks at room
temperature,◦which were isolated by filtration. Yield: 0.25 g (40%);
mp 159–162 C; 1H NMR ([D8]THF, 25 ◦C): d 0.87–1.97 (br, 54H,
Cyp), 4.43 (br d, 4H, 1JPH = 276 Hz, PH2), 6.67–8.28 (br, 50H, Ph).
◦
1
13C{ H} NMR ([D8]THF, 25 C): d 25.2–25.7 (br s, CH2 of Cyp),
29.7, 30.4 (br s, CH2 of Cyp), 35.0, 35.2 (br s, CH of Cyp); 124.7–
◦
1
148.8 (several br s, Ph); 31P{ H} NMR ([D8]THF, 25 C): d 19.9
(br t, J(P,P) = 212.5), 11.3 (br d, J(P,P) = 73.0), 7.78 (br s), −5.0
(br s), −9.7 (br s), −24.7 (m), −46.5 (br s), −70.3 (br s), −79.5 (br
s), −94.0 (br s); FAB-MS, matrix: 3-NBA; m/z (%): 1293.0 (1.2)
[M − CuPCyp3 − 2PH2Ph]+, 819.2 (4.9) [M − Cu − 2PH2Ph −
2PCyp3 − 3Ph = Cu3P8]+, 628.2 (79.8) [M − 2Cu − 2PH2Ph −
PCyp3 − PCyp2 − P4Ph4 = Cu2P4Ph4Cyp]+; IR (cm−1): 3045 m,
2954 s, 2864 s, 2330 m, 2326 w, 1950 w, 1576 m, 1473 m, 1430 m,
1304 s, 1260 s, 1183 m, 1101 s, 1024 s, 908 w, 854 m, 804 s, 736 s,
693 s, 516 w, 494 w, 460 w. Elemental analysis (%): found (calc.
for C90H108P12Cu4, M = 1815.56): C 58.99 (59.53); H 6.11 (6.00).
7 A. Schisler, P. Lo¨nnecke, Th. Gelbrich and E. Hey-Hawkins, Dalton
Trans., 2004, 2895.
8 R. Wolf, S. Go´mez-Ruiz, J. Reinhold, W. Bo¨hlmann and E. Hey-
Hawkins, Inorg. Chem., 2006, 45, 9107.
9 H. Binder, B. Riegel, G. Heckmann, M. Moscherosch, W. Kaim, H.-G.
von Schnering, W. Ho¨nle, H.-J. Flad and A. Savin, Inorg. Chem., 1996,
35, 2119.
10 M. A. Beswick, A. D. Hopkins, L. C. Kerr, M. E. G. Mosquera, J. S.
Palmer, P. R. Raithby, A. Rothenberger, D. Stalke, A. Steiner, A. E. H.
Wheatley and D. S. Wright, Chem. Commun., 1998, 1527.
11 F. Garcia, S. M. Humphrey, R. A. Kowenicki, M. McPartlin and D. S.
Wright, Dalton Trans., 2004, 977.
12 (a) R. Felsberg, S. Blaurock, P. C. Junk, R. Kirmse, A. Voigt and E.
Hey-Hawkins, Z. Anorg. Allg. Chem., 2004, 630, 806; (b) for a related
trinuclear osmium complex with the ligand (P5HPh5)− see: H.-G. Ang,
S.-G. Ang and Q. Zhang, J. Chem. Soc., Dalton Trans., 1996, 2773.
Acknowledgements
We thank Dr P. Lo¨nnecke for his assistance with the X-ray struc-
ture determination and Dr V. Miluykov for valuable advice on the
spectral simulations. Support from the Alexander von Humboldt-
Stiftung (Humboldt-Fellowship for S. G.-R.), the Studienstiftung
des Deutschen Volkes (PhD grant for R. W.) and the Deutsche
Forschungsgemeinschaft is gratefully acknowledged. We would
also like to thank Umicore AG & Co KG for a generous donation
of RhCl3.
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13 SPINWORKS (K. Marat, SPINWORKS, version 2000 05 10, Univer-
sity of Manitoba).
(g) T. A. Annan, R. Kumar and D. G. Tuck, J. Chem. Soc., Dalton
Trans., 1991, 11; (h) A. Eichho¨fer, D. Fenske and W. Holstein, Angew.
Chem., 1993, 105, 257; A. Eichho¨fer, D. Fenske and W. Holstein, Angew.
Chem., Int. Ed. Engl., 1993, 32, 242; (i) M. Faulhaber, M. Driess and K.
Merz, Chem. Commun., 1998, 1887; (j) C. Meyer and H. Gru¨tzmacher,
Angew. Chem., 1997, 109, 2576; C. Meyer and H. Gru¨tzmacher, Angew.
Chem., Int. Ed. Engl., 1997, 36, 2471.
14 (a) R. Blom and A. Haaland, J. Mol. Struct., 1985, 128, 21; (b) M.
Baudler and K. Glinka, Chem. Rev., 1993, 93, 1623.
15 M. Baudler, G. Reuschenbach, J. Hellmann and J. Hahn, Z. Anorg.
Allg. Chem., 1985, 499, 89.
16 For example: (a) T. Greiser and E. Weiss, Chem. Ber., 1978, 111, 516;
(b) G. van Koten, J. G. Noltes and A. L. Spek, J. Organomet. Chem.,
1978, 159, 441; (c) A. H. Cowley, D. M. Giolando, R. A. Jones, C. M.
Nunn and J. M. Power, J. Chem. Soc., Chem. Commun., 1988, 208;
(d) T. A. Annan, R. Kumar and D. G. Tuck, J. Chem. Soc., Chem.
Commun., 1988, 446; (e) D. J. Brauer, G. Hessler, P. C. Knu¨ppel and
O. Stelzer, Inorg. Chem., 1990, 29, 2370; (f) D. J. Brauer, P. C. Knu¨ppel
and O. Stelzer, Phosphorus Sulfur Silicon Relat. Elem., 1990, 49, 449;
17 G. Giordano and R. H. Crabtree, Inorg. Synth., 1990, 28, 88.
18 SCALE3 ABSPACK: Empirical absorption correction, CrysAlis–
Software package, Oxford Diffraction Ltd., Oxford, UK, 2006.
19 G. M. Sheldrick, SHELXS-97, Program for Crystal Structure Solution,
Go¨ttingen, 1997.
20 G. M. Sheldrick, SHELXL-97, Program for the Refinement of Crystal
Structures, Go¨ttingen, 1997.
1988 | Dalton Trans., 2008, 1982–1988
This journal is
The Royal Society of Chemistry 2008
©