Ring size effects in cyclic fluorophosphites: Ligands that span the bonding space between phosphites and PF3

Article abstract of DOI:10.1039/c9dt00893d

The 5- to 8-membered cyclic fluorophosphites L5-8 have been prepared from the corresponding chlorophosphites which are derived from dihydroxyarenes or bis(trimethylsiloxy)arenes. Ligand L5 is very sensitive to hydrolysis but L6-8 are much more kinetically robust. The coordination chemistry of L5-8 has been explored with Mo(0), Pt(0) and Rh(i) and it is shown that the π-acceptor properties of L5-8 increase with decreasing ring size. The IR spectra and X-ray crystal structures of the [Mo(CO)₄L₂] complexes show that L5-8 lie between PF₃ and P(OAr)₃ in terms of their σ/π-bonding properties. The [PtL₄] complexes are readily prepared from [Pt(nbe)₃] and 4 equiv. of L5-8 whereas equilibrium mixtures of PtL_x(nbe)_y species form when 2 equiv. of L5-8 are added to [Pt(nbe)₃]. The CO substitution reactions of [Rh₂Cl₂(CO)₄] with L5-8 to give [Rh₂Cl₂L₄] are evidence of the PF₃-like ligand properties of L5-8. The trends in the properties of L5-8 are analysed in terms of their proximity to PF₃ or P(OPh)₃.

Full text of DOI:10.1039/c9dt00893d

Dalton
Transactions
View Article Online
View Journal
PAPER
Ring size effects in cyclic fluorophosphites:
ligands that span the bonding space between
Cite this: DOI: 10.1039/c9dt00893d
phosphites and PF3†
Alexandra M. Miles-Hobbs, Eliza Hunt, Paul. G. Pringle * and Hazel A. Sparkes
The 5- to 8-membered cyclic fluorophosphites L5–8 have been prepared from the corresponding chloro-
phosphites which are derived from dihydroxyarenes or bis(trimethylsiloxy)arenes. Ligand L5 is very sensi-
tive to hydrolysis but L6–8 are much more kinetically robust. The coordination chemistry of L5–8 has
been explored with Mo(0), Pt(0) and Rh(I) and it is shown that the π-acceptor properties of L5–8 increase
with decreasing ring size. The IR spectra and X-ray crystal structures of the [Mo(CO)4L2] complexes show
that L5–8 lie between PF3 and P(OAr)3 in terms of their σ/π-bonding properties. The [PtL4] complexes are
readily prepared from [Pt(nbe)3] and 4 equiv. of L5–8 whereas equilibrium mixtures of PtLx(nbe)y species
form when 2 equiv. of L5–8 are added to [Pt(nbe)3]. The CO substitution reactions of [Rh2Cl2(CO)4] with
L5–8 to give [Rh2Cl2L4] are evidence of the PF3-like ligand properties of L5–8. The trends in the pro-
perties of L5–8 are analysed in terms of their proximity to PF3 or P(OPh)3.
Received 28th February 2019,
Accepted 2nd April 2019
DOI: 10.1039/c9dt00893d
rsc.li/dalton
hydrocyanation.7 These discoveries inspired numerous sub-
sequent applications of cyclic aryl phosphites,8 phosphorami-
Introduction
Trifluorophosphine has an iconic status in coordination chem- dites (e.g. B),9 phosphonites (e.g. C),10 and fluorophosphites
istry as a ligand that has π-acceptor properties that rival or (e.g. D)11 (see Chart 1). The 7- and 8-membered dioxaphospha-
exceed those of CO;1 an oft-quoted textbook illustration of this cycles present in A–D, entropically stabilize the ligands relative
is the observation that the complexes [M(CO)4] (M = Pd, Pt) to acyclic analogues containing a P(OAr)2 moiety and this
have only fleeting existence in Ar matrices at <10 K whereas leads to two significant advantages for the dioxaphospha-
the PF3 analogues [M(PF3)4] are relatively stable.1,2 Complexes cycles: (1) they are less susceptible to hydrolytic P–O cleavage
of PF3 are known for many transition metals in low oxidation which is a valuable property particularly for their applications
states and the main interest in these complexes has been the in industrial catalysis; (2) they are amenable to systematic
nature of the M–PF3 bonding and the interpretation of their modification because the precursor cyclic chlorophosphites
complicated NMR spectra.1,3
(e.g. E)12 can be readily prepared.
One of the great advantages of P-ligands is the great finesse
The coordination chemistry of cyclic fluorophosphites is of
with which the metal–phosphorus σ/π-bonding can be tuned. The intrinsic interest because their bonding properties should be
Tolman electronic parameter (TEP), the νCO for [Ni(CO)3(PX3)], is intermediate between PF3 and P(OAr)3 and, unlike PF3, their
over 40 years old4 but remains one of the most commonly used stereoelectronic effects can be modified via substituent and
measures of the σ/π-bonding of a P-ligand to a transition metal. ring-size effects. Moreover, the discovery that the cyclic fluoro-
There is a near-continuum of TEP values between P(tBu)3 and phosphite, Ethanox-398 (D), is an excellent ligand for Rh-cata-
P(OPh)3 but a near-void between P(OPh)3 and PF3. We are inter- lysed hydroformylation,11 makes a systematic study of the
ested in the coordination chemistry of ligands that populate this coordination chemistry of cyclic fluorophosphites timely.
gap and have potential applications in catalysis.
Here we present a comparative study of the coordination
Cyclic aryl phosphites such as A emerged as important chemistry of the fluorophosphites L5–8 (Chart 2) containing
ligands in the 1980s and 1990s for hydroformylation5,6 and 5-8-membered dioxaphosphacycles with Mo(0), Pt(0) and Rh(I),
probing the effect of the ring size on their coordination pro-
perties. The chemistry of the phosphite L6a (Chart 2) is also
investigated so that a comparison can be drawn with L6 and
The School of Chemistry, University of Bristol, Cantock’s Close, Bristol, BS8 1TS, UK.
E-mail: paul.pringle@bristol.ac.uk
the effect of the fluoro substituent can be gauged. The 5- and
†Electronic supplementary information (ESI) available. CCDC 1898118–1898123.
7-membered phosphacycles L513,14 and L715 have been pre-
For ESI and crystallographic data in CIF or other electronic format see DOI:
10.1039/c9dt00893d
viously reported and coordination complexes of L5 have been
This journal is © The Royal Society of Chemistry 2019
Dalton Trans.

View Article Online
Paper
Dalton Transactions
Chart 1 Examples of aryl dioxaphosphacycles.
Chart 2
investigated with those concerning Mo(0),16 Pt(0)17 and
Rh(I),18 being pertinent to this study.
Results and discussion
Ligand synthesis
Cyclic fluorophosphites L5–8 and the comparator phosphite
ligand L6a have been prepared from the corresponding cyclic
chlorophosphites, 1a–d. The chlorophosphite precursors can
be prepared by the literature method of the reaction of the diol
with PCl3 in the presence of NEt3 (Scheme 1).19
Scheme 2 Route to chlorophosphites 1a–d via the silyl ethers 2a–d.
Compound 2a and 2c have been previously reported.20,21
A new route to 1a–d from the silyl ethers, 2a–d which
involves a silicon–phosphorus exchange reaction, has been
developed (Scheme 2). The silyl ethers 2a–d are readily pre-
pared from the diol and purified by distillation. The chloro-
phosphites obtained by this route are formed in good yields
Scheme 3
and high purity (see Experimental). The route to 1a–d shown
in Scheme 2 requires 2 steps but this disadvantage is balanced
by the simplicity of the work-up since the ClSiMe3 by-product
is volatile.
Fluorophosphites L5–8 were synthesised, by treatment of
the chlorophosphite precursors 1a–d with 2 equiv. SbF3
(Scheme 3), in moderate yields and characterised by compari-
son to the literature data for L514 and L715 and fully character-
ised for the new compounds L6 and L8 (see Experimental
section). The 31P{1H} and 19F{1H} NMR spectra for L5–8 each
Scheme 1 General procedure for the synthesis of chlorophosphites
1a–d.
Dalton Trans.
This journal is © The Royal Society of Chemistry 2019

View Article Online
Dalton Transactions
Paper
1
showed
a characteristic doublet with large JP,F values
(1240–1309 Hz). No correlations were discerned between the
phosphacycle ring size and the values of 1JP,F, δP, or δF.
Flurophosphite L5 is highly moisture sensitive but the P–F
bonds in L6–8 are considerably more resistant to hydrolysis
than the P–Cl bond in the corresponding chlorophosphites
1b–d. In the presence of water (0.55 M in MeOH), the approxi-
mate times for samples to be 50% hydrolysed were: L5 <
2 min; L6 24 h; L7 40 h; L8 2 h.
Fig. 1 ν(CO) bands (A1) for cis-[Mo(CO)4(L)2] (3a–e).
Table 1 Selected bond lengths (Å) from the molecular structures of
complexes 3a–e
Tetracarbonylmolybdenum complexes
Complexes of the type cis-[Mo(CO)4L2] were targeted as a way
to compare the stereoelectronic properties of L5–8 from their
IR spectra and X-ray crystal structures.
Ligand
Complex
Mo–P/Å
P–F/Å
Mo–Ca/Å
G
x b (%)
L5
L6
L7
3a
3b
3c
2.3794(4)
2.3846(6)
2.3891(4)
1.5735(10)
1.5832(13)
1.5744(10)
2.0330(17)
2.042(2)
2.0532(16)
2.0466(16)
2.015(3)
2.032(2)
2.0165(18)
2.0258(17)
17.5
17.3
20.3
21.0
17.8
23.4
18.5
20.0
Ligands L5–8 react smoothly with [Mo(CO)4(nbd)] (nbd =
norbornadiene) in CH2Cl2 to give the cis-[Mo(CO)4L2] com-
plexes 3a–d, where L = L5–8 (Scheme 4).
L8
3d
3e
2.4037(6)
1.5758(14)
The 31P{1H} and 19F{1H} NMR spectra for each complex
(3a–d) showed a doublet of triplets which is a deceptively
simple pattern for the AA′XX′ spin system; the separation of
L6a
2.4270(4)
2.4163(4)
—
a Mo–C bond length trans to P. b The Gx areas were calculated using the
following van der Waals radii (Å): C 1.7, H 1.09, F 1.47, Mo 2, O 1.52
and P 1.8.
3
the doublet (corresponding to N = |1JPF + JPF|) is of the order
of 1200 Hz in each case. The NMR spectra were simulated
using the coupling constants given in the Experimental
section (see ESI† for an example) and the values computed for
2JP,P are of the order of 50 Hz consistent with a cis-geometry.
The coordination chemical shift Δδ for L5–8 in 3a–d is ca.
40 ppm which is similar to that for L6a in 3e. There do not
appear to be consistent correlations between the NMR data for
3a–d and the ring size of L5–8.
The IR spectra for complexes 3a–d are consistent with a cis
geometry of ligands. The ν(CO) (A1) values for [Mo(CO)4L2] can
be used as a proxy for the TEP since they are linearly related.22
From the values given in the Experimental section and illus-
trated in Fig. 1, the fluorophosphites L5–8 sit between PF3 and
P(OPh)3 in terms of their TEP, with the smallest phosphacycle
L5 being closest to PF3. This is consistent with the reported
correlation between the ligand ring size and energies of the
frontier orbitals:23 the smaller the O–P–O angle, the lower
lying the HOMO and LUMO energies. The ν(CO) values for the
complexes 3b and 3e featuring the six-membered phospha-
cycles L6 and L6a (2066 and 2051 cm−1 respectively) reflect the
significant difference between the ligands having P–F and
P–OMe fragments.
order 3d > 3c > 3b > 3a, consistent with increasing Mo–P bond
strength as the phosphacycle ring size decreases as a result of
the π-acceptor capacity increasing in the order L5 > L6 > L7 >
L8. The Mo–P π-bonding should perturb the bond lengths and
angles around the P atom23 but these effects may be very
subtle since no trends in P–O/P–F bond lengths or O–P–F
angles are evident in the crystallographic data (see ESI†). The
Mo–P bond length in complex 3b is considerably shorter than
in 3e, consistent with the fluorophosphite L6 having a greater
π-acceptor capacity than its methoxyphosphite analogue, L6a.
The fluorophosphite ligands adopt a syn-conformation in com-
plexes 3a and 3c and an anti-conformation in complexes 3b
and 3d, which may be indicative of syn- and anti-conformers
being close in energy. The steric properties of the P-ligands in
3a–3e were assessed using the solid angles approach.24 The G
parameter, calculated from the crystal structures (Gx) rep-
resents the area of the metal centre shielded by the ligand.
Interpretation of the Gx values given in Table 1 is complicated
by there being two values for L7 in 3c and for L8 in 3d because
the coordinated ligands adopt different geometries and hence
there are two unique P environments in the crystallographic
asymmetric unit. Nevertheless, the data suggest that in the Mo
structures of 3a–e, L5/L6 have similar bulk, as do L7/L8 and
that L5/L6 are smaller than L7/L8; the phosphite L6a is larger
than its fluorophosphite analogue L6.
Crystals suitable for X-ray crystallography of complexes 3a–e
were grown by slow diffusion of hexane into a saturated
CH2Cl2 solution of the complex or by storing a saturated
hexane solution of complex at −20 °C. Selected metrical data
are given in Table 1 and full details are given in the ESI.† In
each case, the crystal structures confirmed the cis geometry of
the complexes (Fig. 2). The Mo–P bond lengths decrease in the
Scheme 4
This journal is © The Royal Society of Chemistry 2019
Dalton Trans.

View Article Online
Paper
Dalton Transactions
Fig. 2 Crystal structures of [Mo(CO)4L2]: (a) L = L5 (3a); (b) L = L6 (3b); (c) L = L7 (3c); (d) L = L8 (3d); (e) L = L6a (3e). The hydrogen atoms are
omitted for clarity. Thermal ellipsoids at 50% probability. See Table 1 for selected bond lengths and the ESI† for full lists of bond lengths and angles.
Platinum(0) complexes
solutions of [Pt(nbe)3] and L6 into each other. The crystal
structure (Fig. 4a) confirms the coordination of four ligands to
the Pt(0) in an approximately tetrahedral arrangement. There
are multiple, intermolecular π⋯π and C–H⋯π interactions
between the aryl rings of the ligands detected in the solid state
producing an extended structure (Fig. 4b). These inter-
molecular interactions may explain the lack of solubility of 4b.
In support of this, the analogous phosphite complex [Pt(L6a)4]
(4e) is soluble in common organic solvents and its crystal
structure (see ESI† for details) shows no such network of inter-
molecular interactions.
The phosphite ligand L6a also formed a [PtL4] complex
upon addition of 4 equiv. of ligand to [Pt(nbe)3] as shown by
the binomial quintet in its 195Pt{1H} NMR spectrum (see
Experimental for the data). Therefore the formation of the
18-electron [PtL4] complex is common to L = PF3 L5–8, L6a and
P(OPh)3.25
The reaction of 4 equiv. of ligands L5–8 or L6a with [Pt(nbe)3]
(nbe = norbornene) gave the 4-coordinate, 18-electron com-
plexes, [PtL4] (4a–e) (Scheme 5). Goodfellow et al. previously
synthesised complex 4a from [Pt(cod)2] and L5.17 Complicated
AA′3XX′3 patterns for the 31P{1H} and 19F{1H} NMR spectra
were obtained for each of the [PtL4] complexes 4a,c,d and the
195Pt{1H} NMR spectra are binomial quintets of quintets in
each case (see Fig. 3 for the NMR spectra of 4c).
The complex [Pt(L6)4] (4b) is insoluble in all common sol-
vents and so we were unable to characterise it by NMR spec-
troscopy but crystals of 4b suitable for X-ray crystallography
were obtained by the slow diffusion of layered chlorobenzene
Differences emerged between the cyclic fluorophosphite
in the reaction of [Pt(nbe)3] with 2 equiv. of L5–8. The expec-
tation was that [PtL2(nbe)] (L = L5–8) would be the products
Scheme 5
Dalton Trans.
This journal is © The Royal Society of Chemistry 2019

View Article Online
Dalton Transactions
Paper
Fig. 4 Crystal structure of [Pt(L6)4]·C6H5Cl. Thermal ellipsoids at 50%
probability. (a) Molecular structure of 4b (C6H5Cl solvate molecules and
hydrogens are omitted for clarity). Selected bond lengths (Å) and angles
(°): P1–F1 1.575(3), Pt1–P1 2.2303(12), P1–Pt1–P1(−0.5 + y, 1 − x, −z)
107.61(3), O1–P1–O2 102.61(18). (b) Extended structure highlighting the
intermolecular π⋯π interactions indicated by red dashed lines. The π⋯π
interaction distances are 3.964 Å with a shift of 2.07 Å. Weak C–H-π
interactions with C–H-plane ∼2.87 Å (or H-centroid distance of 3.03 Å),
plane centroid-H–C angle 157° are also present but these are not
highlighted.
Fig. 3 NMR spectra of [Pt(L7)4] (4c) in d8-THF. (a) 31P{1H}; (b) 19F{1H}; (c)
195Pt{1H}.
Scheme 6
but instead, the equilibria shown in Scheme 6 involving Pt(0)
species 4–7 were observed. Structures 4–7 have been assigned
on the basis of the characteristic splitting patterns present in insoluble white precipitate assumed to be 4b (see above) and
the 31P{1H} NMR spectra and the multiplicity of the 195Pt{1H} in the filtrate 6b and 7b were both identified by 31P{1H} and
NMR signals (see Experimental for the data and ESI† for the 195Pt{1H} NMR spectroscopy. Addition of 2 equiv. of L7 to
spectra). The [PtL3] species 5a–d have not been detected but [Pt(nbe)3] initially gave [PtL4] (4c) which, over the next 2 h,
are presumably intermediates that are unstable with respect to equilibrated to a mixture of 4c, 6c and 7c (see ESI†). Addition
4a–d and 6a–d. Addition of 2 equiv. of L5 to [Pt(nbe)3] gave a of 2 equiv. of L8 to [Pt(nbe)3] initially gave [PtL4] (4d) which
mixture of 4a (identified as above), 6a (identified by the AA′XX′ then converted to predominantly 6d. The proportions of the
pattern for its 31P{1H} NMR signal and the triplet of triplets for species obtained at equilibrium are given in Scheme 6.
its 195Pt{1H} NMR signal), 7a (identified by the doublet for its
Interpretation of the data is complicated by the accuracy of
31P{1H} NMR signal and doublet of doublets for its 195Pt{1H} integrating 31P{1H} NMR signals, the presence of small
NMR signal). Addition of 2 equiv. of L6 to [Pt(nbe)3] gave an amounts (<5%) of [Pt(nbe)3] which are impractical to detect in
This journal is © The Royal Society of Chemistry 2019
Dalton Trans.

View Article Online
Paper
Dalton Transactions
Scheme 7
the 195Pt{1H} NMR spectra; moreover for the L6 system, pre- ing the five-coordinate Rh cation on the basis of: (a) the com-
cipitation of 4b makes the mixture inhomogeneous and there- plicated 31P{1H} and 19F{1H} spectra, as expected for an
fore is not included. Despite these provisos, it appears that AA′4MM′4X spin system (see ESI†); (b) the reaction of 5 equiv.
there is a trend in the amount of [PtL2(nbe)] formed with of L6 to [Rh(cod)2]BF4 gave a single product which had the
increasing size and decreasing π-acceptor capacity of the phos- same 31P{1H} NMR spectrum as 9b and in the 19F{1H} NMR
phacycle and vice versa for the trend in the amount of [PtL4] spectrum, two signals in the ratio 5 : 4 were observed, consist-
formed.
ent with the structure [Rh(L6)5][BF4] (9b′). The IR spectrum of
When 2 equiv. of L6a was added to [Pt(nbe)3], the product the product mixture showed bands for [Rh2Cl2(CO)4], as would
was initially 4e which equilibrated over 1 h to give 4e (35%), 6e be expected to balance the stoichiometry (Scheme 7) but no
(53%) and 7e (12%) identified from the quintet, triplet and other Rh–CO bands.
doublet respectively in the 195Pt{1H} NMR spectrum. The Pt(0)
chemistry of the phosphite L6a therefore resembles that of L7.
According to 31P{1H} and 19F{1H} NMR spectroscopy, the
mixtures of products formed from the addition of fluoropho-
sphites L7 or L8 to [Rh2Cl2(CO)4] contain binuclear 8c or 8d,
and the salts 9c or 9d. In addition minor products (<15%)
were observed which were tentatively assigned to the structures
trans-[RhCl(CO)L2] (10c or 10d) on the basis of the IR spectrum
of the mixtures which showed ν(CO) bands at 2032 cm−1 (for
10c) and 2028 cm−1 (for 10d). It was found that reaction of
[Rh2Cl2(CO)4] with phosphite L6a gave 10e as the main
product with a ν(CO) band at 2023 cm−1. There is a trend in
the reactions of [Rh2Cl2(CO)4] with the fluorophosphites on
increasing the ring size from L5 to L8: the chemistry with L5
resembles PF3 and as the ring size expands, the chemistry pro-
gressively moves towards resembling that of phosphite L6a.
Rh(I) complexes
Nixon et al.18 showed that 8a is the product of the addition of
L5 to [Rh2Cl2(C6H10)2]. Complex 8a is also the sole product of
the reaction of [Rh2Cl2(CO)4] with 4 equiv. of L5 (Scheme 7) as
shown by the absence of CO bands in the IR spectrum and the
19F{1H} and 31P{1H} NMR spectra. This is an indication of the
high π-acidity of L5 since displacing CO from [Rh2Cl2(CO)4] is
26
a reaction only observed with PF3 and a few chelating fluoro-
aryl diphosphines.27
When [Rh2Cl2(CO)4] was treated with 4 equiv. of L6, two
P-containing products formed that have been identified from
their 31P{1H} and 19F{1H} NMR spectra (see ESI† for the
spectra); the broad spectra obtained at ambient temperatures
were resolved at −40 °C indicating that the species were
exchanging on the NMR timescale. The binuclear complex 8b
Conclusions
formed by CO displacement by L6 was assigned to the major The coordination chemistry of fluorophosphites has received
component (ca. 80%) of the product mixture on the basis of little systematic attention despite the intrinsic interest in inves-
the observation that the same species was formed exclusively tigating ligands that should have properties lying between
upon addition of 4 equiv. of L6 to [Rh2Cl2(cod)2] (see P(OAr)3 and PF3. The aim of this work was to explore the effect
Experimental). The minor component of the product from of ring size on the coordination chemistry of cyclic fluoropho-
[Rh2Cl2(CO)4] was assigned to the salt [Rh(L6)5]Cl (9b) featur- sphites L5–8.
Dalton Trans.
This journal is © The Royal Society of Chemistry 2019

View Article Online
Dalton Transactions
Paper
From the IR spectra of the complexes [Mo(CO)4L2], where molecular sieves. PCl3 and SiMe3Cl were distilled before use
L = L5–6, the ν(CO) values confirmed the expectation that and deoxygenated by N2 saturation. All commercial reagents
these ligands would populate the space between P(OAr)3 and were purchased from Sigma-Aldrich and used as supplied,
PF3 in terms of their σ/π-bonding to transition metals. aside from 2-chloro-1,3,2-benzodioxaphosphole (1a), which
Pronounced effects of ring size on the stereoelectronic pro- was distilled and used in the large-scale synthesis of L5.
perties of the ligands are evident and can be summarised in
All NMR spectra were recorded on a Jeol ECP (Eclipse) 300,
terms of the following trends for L5–8: (1) the smaller the Varian 400-MR, or Jeol ECS 400 spectrometer. Mass spectra
phosphacycle, the closer the fluorophosphite properties are to were carried out by the University of Bristol Mass Spectrometry
PF3, so L5 is the most PF3-like of the series; (2) the steric bulk Service on a VG Analytical Autospec (EI) or VG Analytical
of the ligands is in the order: L5/L6 < L7/L8. Using these gener- Quattro (ESI) spectrometer. Crystal structures were determined
alisations, the chemistry of the platinum(0) and rhodium(I) by the University of Bristol Crystallography Service, using a
complexes of L5–8 that is reported here can be understood.
Bruker APEX II diffractometer. Infra-red spectroscopy was
The 18-electron [PtL4] complexes are common to the whole carried out on
series from PF3 through L5–8 to P(OPh)3. A trend emerged in Spectrometer.
the proportions of [PtL4] and [PtL2(nbe)] that formed from the
a
PerkinElmer Spectrum One FT-IR
Synthesis of silyl ethers 2a–d
addition of 2 equiv. of L5–8 to [Pt(nbe)3]. With L5, [PtL4] was
the major species (77%) whereas with L8, [PtL2(nbe)] predomi-
Synthesis of 2a. A solution of catechol (0.400 g, 3.63 mmol)
nated (91%). This trend is likely a consequence of the balance in THF (20 mL) was cooled to −78 °C and n-BuLi (5.00 mL,
of steric factors ([PtL4] is more crowded than [PtL2(nbe)]) and 7.99 mmol, 1.6 M in hexanes) was added dropwise over
electronic characteristics (fluorophosphites are more able to 10 min. The reaction mixture was then allowed to warm to
stabilise Pt(0) than nbe).
ambient temperature and stirred for a further 2 h. SiMe3Cl
The reaction of [Rh2Cl2(CO)4] with P(OAr)3 to give trans- (1.01 mL, 7.99 mmol) was then added dropwise over 10 min
[RhCl(CO){P(OAr)3}2] is general. The substitution of CO in and the reaction mixture stirred for 20 h. The volatiles were
[Rh2Cl2(CO)4] by the cyclic fluorophosphites to give [Rh2Cl2L4] removed under reduced pressure and the residue was dissolved
(L = L5–8) is an excellent illustration of their PF3-like pro- in toluene (20 mL). The suspension was filtered, and the solid
perties; to the best of our knowledge, the only monodentate washed with toluene (3 × 10 mL). The volatiles were removed
P-ligand that is reported to behave similarly is PF3. Moreover under reduced pressure to yield the crude product.
the observed trend in the extent to which this CO substitution Purification by distillation (70 °C, 0.5 Torr) gave the product as
occurs reflects the closeness of the ligand to PF3: [Rh2Cl2L4] is a colourless oil (0.786 g, 85%). 1H NMR (400 MHz, CDCl3):
1
formed exclusively when L = L5 but constitutes only 65% of δH (ppm) 6.86 (m, 4H, ArCH), 0.28 (s, JH,C = 119 Hz, 18H,
the product when L = L8.
Si(CH3)3). 13C{1H} NMR (101 MHz, CDCl3): δC (ppm) 124.8
It has been shown that the coordination properties of cyclic (s, ArCO), 122.0 (s, ArCH), 121.3 (s, ArCH), 0.5 (s, 1JC,Si = 60 Hz,
fluorophosphites can be tuned by variation in the ring size. Si(CH3)3). H and 13C{1H} NMR data agreed with the literature
1
The decoration of the rings with substituents should provide data.20
ample opportunities for the fine control of stereoelectronic
Synthesis of 2b. A solution of the 1,8-dihydroxynaphthalene
effects of this class of modifiable, super-π-acceptor ligands. (2.00 g, 12.5 mmol) in THF (35 mL) was cooled to −78 °C and
This may lead to applications in catalysis beyond the hydrofor- n-BuLi (17.2 mL, 27.5 mmol, 1.6 M in hexanes) was added
mylation catalysis that has already been demonstrated with the dropwise over 10 min. The reaction mixture was then allowed
cyclic fluorophosphite, Ethanox-398.11
to warm to ambient temperature and stirred for a further 2 h.
SiMe3Cl (3.49 mL, 27.5 mmol) was then added dropwise over
10 min and the reaction mixture stirred for 20 h. The volatiles
were removed under reduced pressure and the residue was dis-
solved in toluene (30 mL). The suspension was filtered, and
the solid washed with toluene (3 × 15 mL). The volatiles were
Experimental
General considerations
Syntheses were carried out under a N2 atmosphere using stan- removed under reduced pressure to yield the crude product.
dard Schlenk line and glove-box techniques, unless otherwise Purification by kugelrohr distillation (110 °C, 1 × 10−6 Torr)
stated. Acetonitrile, toluene, dichloromethane, tetrahydro- gave the product as a colourless oil (2.72 g, 72%). 1H NMR
furan, hexane and diethyl ether were collected from a Grubbs (400 MHz, CDCl3): δH (ppm) 7.41 (d, JH,H = 8 Hz, 2H, ArCH),
type solvent system and deoxygenated by three successive 7.27 (t, JH,H = 8 Hz, 2H, ArCH), 6.80 (d, JH,H = 8 Hz, 2H, ArCH),
freeze–pump–thaw cycles and stored over 3 Å or 4 Å molecular 0.27 (s, 1JH,C = 120 Hz, 18H, Si(CH3)3). 13C{1H} NMR (101 MHz,
sieves. Deuterated dichloromethane (CD2Cl2), chloroform CDCl3): δC (ppm) 152.0 (s, ArCO), 138.0 (s, ArC), 126.0 (s,
(CDCl3), benzene (C6D6) and tetrahydrofuran (d8-THF) were ArCH), 122.6 (s, ArC), 121.9 (s, ArCH), 116.2 (s, ArCH), 0.7 (s,
dried over activated 4 Å molecular sieves and deoxygenated by 1JC,Si = 60 Hz, Si(CH3)3). HR-MS (EI): m/z calcd for C16H24O2Si2
three successive freeze–pump–thaw cycles. Triethylamine was [M]+ = 304.1315; obs. = 304.1309.
reacted with CaH2 overnight, distilled and deoxygenated by
Synthesis of 2c. A solution of the 2,2′-dihydroxybiphenyl
three successive freeze–pump–thaw cycles and stored over 4 Å (0.100 g, 0.536 mmol) in THF (10 mL) was cooled to −78 °C
This journal is © The Royal Society of Chemistry 2019
Dalton Trans.

View Article Online
Paper
Dalton Transactions
and n-BuLi (0.737 mL, 1.18 mmol, 1.6 M in hexanes) was 7.14 (d, JH,H = 8 Hz, 2H, ArCH), 6.92 (t, JH,H = 8 Hz, 2H, ArCH),
added dropwise over 10 min. The reaction mixture was then 6.71 (d, JH,H = 8 Hz, 2H, ArCH). 31P{1H} and 1H NMR data
allowed to warm to ambient temperature and stirred for a agreed with the literature data.29
further 2 h. SiMe3Cl (1.50 mL, 1.18 mmol) was then added
Synthesis of 1c. To a solution of 2c (0.100 g, 0.303 mmol) in
dropwise over 10 min and the reaction mixture stirred for 20 h. MeCN (2 mL) was added PCl3 (0.264 mL, 3.03 mmol). The reac-
The volatiles were removed under reduced pressure and the tion mixture was stirred until completion (3 h), as identified
residue was dissolved in toluene (10 mL). The suspension was by 31P{1H} NMR spectroscopy. The volatiles were removed
filtered, and the solid washed with toluene (3 × 5 mL). The under reduced pressure to yield the product as a pale yellow
volatiles were removed under reduced pressure to yield the oil (0.0770 g, 99%). 31P{1H} NMR (162 MHz, C6D6): δP (ppm)
1
crude product. Purification by distillation (110 °C, 0.5 Torr) 179.5 (s). H NMR (400 MHz, C6D6): δH (ppm) 7.48 (dd, JH,H
=
gave the product as a yellow oil (0.101 g, 57%). 1H NMR 8, 1 Hz, 2H, ArCH), 7.37 (m, 4H, ArCH), 7.38 (dd, JH,H = 8, 1
(400 MHz, CDCl3): δH (ppm) 7.31–7.18 (m, 4H, ArCH), 7.00 (m, Hz, 2H, ArCH). 31P{1H} and H NMR data agreed with the lit-
1
2H, ArCH), 6.88 (dd, JH,H = 8, 1 Hz, 2H, ArCH), 0.08 (s, 18H, erature data.30
Si(CH3)3). 13C{1H} NMR (101 MHz, CDCl3): δC (ppm) 153.2 (s,
Synthesis of 1d. To a solution of 2d (1.82 g, 5.28 mmol) in
ArCO), 132.0 (s, ArCH), 131.0 (s, ArC), 128.3 (s, ArCH), 120.8 (s, MeCN (25 mL) was added PCl3 (4.61 mL, 52.8 mmol). The reac-
1
ArCH), 119.7 (s, ArCH), 0.4 (s, Si(CH3)3). H and 13C{1H} NMR tion mixture was heated at 50 °C for 48 h. The volatiles were
data agreed with the literature data.21
then removed under reduced pressure. To ensure complete
Synthesis of 2d. A solution of the bis(2-hydroxyphenyl) conversion of the dichlorophosphorus intermediate, the iso-
methane (1.50 g, 7.49 mmol) in THF (30 mL) was cooled to lated crude product was redissolved in MeCN (20 mL) and
−78 °C and n-BuLi (10.3 ml, 16.5 mmol, 1.6 M in hexanes) was heated at 60 °C for 20 h. Upon completion of the reaction, the
added dropwise over 10 min. The reaction mixture was then volatiles were removed under reduced pressure to yield the
allowed to warm to ambient temperature and stirred for a product as a white solid (1.35 g, 95%). 31P{1H} NMR (162 MHz,
further 2 h. SiMe3Cl (2.09 ml, 16.5 mmol) was then added C6D6): δP (ppm) 125.7 (s), −0.7 (s, 7% hydrolysis). 31P{1H} NMR
dropwise over 10 min and the reaction mixture stirred for 20 h. data agreed with the literature data.31 1H NMR (400 MHz,
The volatiles were removed under reduced pressure and the C6D6): δH (ppm) 6.88 (d, JH,H = 7 Hz, 2H, ArCH), 6.75 (m, 6H,
2
residue was dissolved in toluene (25 mL). The suspension was ArCH), 6.72 (d, JP,H = 743 Hz, 0.04H, hydrolysis PH), 4.24 (d,
2
filtered, and the solid washed with toluene (3 × 15 mL). The 2JH,H = 13 Hz, 1H, CH2), 3.81 (d, JH,H = 15 Hz, 0.04H, hydro-
2
2
volatiles were removed under reduced pressure to yield the lysis), 3.60 (d, JH,H = 14 Hz, 0.04H, hydrolysis), 3.01 (d, JH,H
=
crude product. Purification by kugelrohr distillation (170 °C, 13 Hz, 1H, CH2). 13C{1H} NMR (101 MHz, C6D6): δC (ppm)
1 × 10−6 Torr) gave the product as a colourless oil (1.82 g, 71%). 150.3 (d, JC,P = 15 Hz, ArCO), 134.5 (s, ArC), 130.1 (s, ArCH),
2
1H NMR (400 MHz, CDCl3): δH (ppm) 7.10 (td, JH,H = 8, 2 Hz, 127.8 (s, ArCH), 125.9 (s, ArCH), 123.7 (s, ArCH), 33.8 (s, CH2).
2H, ArCH), 7.01 (dd, JH,H = 8, 2 Hz, 2H, ArCH), 6.88 (td, JH,H = 7,
Synthesis of fluorophosphite ligands (L5–8)
1 Hz, 2H, ArCH), 6.82 (dd, JH,H = 8, 1 Hz, 2H, ArCH), 3.91 (s, 2H,
CH2), 0.25 (s, 18H, Si(CH3)3). 13C{1H} NMR (101 MHz, CDCl3):
Synthesis of L5. A solution of 1a (4.50 g, 25.2 mmol) in Et2O
δC (ppm) 153.7 (s, ArCO), 131.7 (s, ArC), 130.9 (s, ArCH), 127.0 (10 mL) was added to a suspension of SbF3 (9.01 g, 50.4 mmol)
(s, ArCH), 121.3 (s, ArCH), 118.8 (s, ArCH), 30.7 (s, CH2), 0.6 in Et2O (10 mL). The reaction mixture was stirred at ambient
1
(s, JC,Si = 60 Hz, Si(CH3)3). HR-MS (ESI): m/z calcd for temperature for 20 h. The resultant mixture was fractionated
C19H28NaO2Si2 [M + Na]+ = 367.1520; obs. = 367.1527.
by vacuum distillation (0.1 Torr) using cooling baths at
−20 °C, −40 °C and −78 °C. The traps at −20 °C and −40 °C
contained clear oils, which upon NMR analysis were found to
Synthesis of chlorophosphites 1a–d
Synthesis of 1a. To a solution of 2a (0.125 g, 0.491 mmol) in be pure L5 (1.45 g, 73%). 31P{1H} NMR (162 MHz, C6D6):
MeCN (2 mL) was added PCl3 (0.428 mL, 4.91 mmol). The reac- δP (ppm) 124.3 (d, JP,F = 1306 Hz). 19F{1H} NMR (377 MHz,
1
1
1
tion mixture was stirred until completion (2 h), as identified C6D6): δF (ppm) −37.2 (d, JF,P = 1306 Hz). H NMR (400 Hz,
by 31P{1H} NMR spectroscopy. The volatiles were removed C6D6): δH (ppm) 7.21 (dd, JH,H = 6, 3 Hz, 2H, ArCH), 7.09 (dd,
under reduced pressure to yield the product as a pale yellow JH,H = 6, 3 Hz, 2H, ArCH). 31P{1H}, 19F{1H} and H NMR data
1
solid (0.0860 g, 99%). 31P{1H} NMR (162 MHz, C6D6): δP (ppm) agreed with the literature data.14
174.4 (s). 1H NMR (400 MHz, C6D6): δH (ppm) 6.73 (m, 2H,
Synthesis of L6. A solution of 1b (1.10 g, 4.90 mmol) in
1
ArCH), 6.55 (m, 2H, ArCH). 31P{1H} and H NMR data agreed toluene (15 mL) was added to a suspension of SbF3 (1.75 g,
with the literature data.28
9.80 mmol) in toluene (15 mL). The reaction mixture was
Synthesis of 1b. To a solution of 2b (2.38 g, 7.80 mmol) in stirred at ambient temperature until the reaction was com-
MeCN (40 mL) was added PCl3 (6.81 mL, 78.0 mmol). The reac- pleted according to 31P{1H} NMR and then passed through a
tion mixture was heated at 60 °C until completion (20 h), as short silica column, which was then washed with toluene (3 ×
identified by 31P{1H} NMR spectroscopy. The volatiles were 10 mL). The solvent was removed under reduced pressure to
removed under reduced pressure to yield the product as a yield the product as a colourless oil (0.560 g, 55%). 31P{1H}
1
white solid (1.68 g, 96%). 31P{1H} NMR (162 MHz, C6D6): NMR (162 MHz, C6D6): δP (ppm) 100.6 (d, JP,F = 1241 Hz). 19F
1
δP (ppm) 133.0 (s). 1H NMR (400 MHz, C6D6): δH (ppm) {1H} NMR (377 MHz, C6D6): δF (ppm) −52.7 (d, JF,P = 1241
Dalton Trans.
This journal is © The Royal Society of Chemistry 2019

View Article Online
Dalton Transactions
Paper
1
Hz). H NMR (400 MHz, C6D6): δH (ppm) 7.11 (d, JH,H = 8 Hz, (ESI): m/z calcd for C11H10O3P [M + H]+ = 221.0368; obs. =
2H, ArCH), 6.91 (t, JH,H = 8 Hz, 2H, ArCH), 6.69 (d, JH,H = 8 Hz, 221.0360.
2H, ArCH). 13C{1H} NMR (101 MHz, C6D6): δC (ppm) 142.6 (s,
Synthesis of cis-[Mo(CO)4L2] complexes (3a–e)
ArCO), 134.9 (s, ArC), 127.3 (s, ArCH), 122.9 (s, ArCH), 116.3 (d,
2JC,P = 16 Hz, ArC), 112.2 (s, ArCH). HR-MS (EI): m/z calcd for
General procedure. To
a solution of [Mo(CO)4(nbd)]
C10H6FO2P [M]+ = 208.0089; obs. = 208.0087.
(0.0200 g, 0.0670 mmol) in CH2Cl2 (0.5 mL) was added a solu-
Synthesis of L7. A solution of 1c (2.36 g, 10.0 mmol) in tion of the ligand (0.133 mmol) in CH2Cl2 (0.5 mL) and stirred
toluene (30 mL) was added to a suspension of SbF3 (3.58 g, for 4 h.
20.0 mmol) in toluene (20 mL). The reaction mixture was
cis-[Mo(CO)4(L5)2] (3a). Upon completion of the reaction,
stirred at ambient temperature until the reaction was com- the volatiles were removed under reduced pressure and the
pleted according to 31P{1H} NMR and then passed through a crude product was dissolved in toluene (2 mL) and then the
short silica column, which was then washed with toluene (3 × solvent removed to yield the product as a pale-yellow solid
15 mL). The solvent was removed under reduced pressure to (0.0300 g, 86%). Crystals suitable for analysis by single crystal
yield the product as a white solid (1.54 g, 66%). 31P{1H} NMR X-ray diffraction were grown by storing a saturated hexane solu-
1
(162 MHz, C6D6): δP (ppm) 135.8 (d, JP,F = 1309 Hz). 31P{1H} tion of 3a at −20 °C for 48 h. 31P{1H} NMR (162 MHz, CD2Cl2):
1
2
data agreed with the literature data.15 19F{1H} NMR (377 MHz, δP (ppm) 170.2 (dt, N = 1270 Hz, JP,F = 1271 Hz, JP,P′ = 51 Hz,
C6D6): δF (ppm) −52.4 (d, JF,P = 1309 Hz). H NMR (400 MHz, 4JF,F′ = 0 Hz, 3JP,F′ = −1 Hz, see ESI† for coupling constant calcu-
1
1
C6D6): δH (ppm) 7.39 (dd, JH,H = 8, 2 Hz, 2H, ArCH), 7.30 (td, lations). 19F{1H} NMR (377 MHz, CD2Cl2): δF (ppm) −0.9 (dt,
1
2
4
3
JH,H = 8, 2 Hz, 2H, ArCH), 7.27–7.22 (m, 2H, ArCH), 7.13 (dt, N = 1270 Hz, JF,P = 1271 Hz, JP,P′ = 51 Hz, JF,F′ = 0 Hz, JF′,P
=
JH,H = 8, 1 Hz, 2H, ArCH). 13C{1H} NMR (101 MHz, C6D6): −1 Hz). 1H NMR (400 MHz, CD2Cl2): δH (ppm) 7.17 (m, 2H,
δC (ppm) 148.5 (m, ArCO), 131.2 (d, 3JC,P = 3 Hz, ArC), 130.4 (s, ArCH), 7.12 (m, 2H, ArCH). 13C{1H} NMR (101 MHz, CD2Cl2):
2
ArCH), 129.6 (s, ArCH), 126.0 (s, ArCH), 122.3 (s, ArCH).
δC (ppm) 205.9 (m, Mo–CO), 202.9 (t, JC,P = 14 Hz, Mo–CO),
2
Synthesis of L8. A solution of 1d (1.75 g, 6.61 mmol) in 145.4 (d, JC,P = 6 Hz, ArCO), 124.6 (s, ArCH), 113.3 (m, ArCH).
toluene (25 mL) was added to a suspension of SbF3 (2.36 g, HR-MS (ESI): m/z calcd for C16H8FMoO8P2 [M − F]+ = 506.8731;
13.2 mmol) in toluene (15 mL). The reaction mixture was obs. = 506.8749. IR (CH2Cl2): ν(CO) = 2072 cm−1
.
stirred at ambient temperature until the reaction was com-
cis-[Mo(CO)4(L6)2] (3b). Upon completion of the reaction,
pleted according to 31P{1H} NMR and then passed through a the volatiles were removed under reduced pressure. The
short silica column, which was then washed with toluene (3 × product was triturated with hexane (2 mL). The solid was
15 mL). The solvent was removed under reduced pressure to allowed to settle, and supernatant was removed; residual
yield the product as a colourless oil (1.20 g, 73%). 31P{1H} solvent was removed from the solid under reduced pressure to
1
NMR (162 MHz, C6D6): δP (ppm) 107.8 (d, JP,F = 1254 Hz). 19F yield the product as a pale-yellow solid (0.0270 g, 65%).
1
{1H} NMR (377 MHz, C6D6): δF −62.2 (d, JF,P = 1254 Hz, Crystals suitable for analysis by single crystal X-ray diffraction
>96%). 1H NMR (400 MHz, C6D6): δH (ppm) 6.88 (d, JH,H
=
were grown by slow diffusion of hexane into a saturated
7 Hz, 2H, ArCH), 6.77 (m, 6H, ArCH), 4.02 (d, 2JH,H = 14 Hz, 1H, CH2Cl2 solution of 3b. 31P{1H} NMR (162 MHz, CD2Cl2): δP
CH2), 3.31 (d, 2JH,H = 14 Hz, 1H, CH2). 13C{1H} NMR (101 MHz, (ppm) 144.3 (dt, N = 1194 Hz, JP,F = 1199 Hz, JP,P′ = 51 Hz,
1
2
C6D6): δC (ppm) 148.5 (t, J = 7 Hz, ArCO), 133.7 (d, 3JC,P = 2 Hz, 4JF,F′ = 0 Hz, 3JP,F′ = −5 Hz). 19F{1H} NMR (377 MHz, CD2Cl2): δF
1
2
ArC), 130.2 (s, ArCH), 128.4 (s, ArCH), 125.7 (s, ArCH), 122.9 (ppm) −23.2 (dt, N = 1194 Hz, JF,P = 1199 Hz, JP,P′ = 51 Hz,
(d, JC,P = 2 Hz, ArCH), 34.4 (s, CH2). HR-MS (MALDI): m/z calcd 4JF,F′ = 0 Hz, JF′,P = −5 Hz). 1H NMR (400 MHz, CD2Cl2):
3
for C13H10FO2P [M + H]+ = 249.0475; obs. = 249.0481.
δH (ppm) 7.62 (d, JH,H = 8 Hz, 2H, ArCH), 7.45 (m, 2H, ArCH),
Synthesis of L6a. NEt3 (0.31 mL, 2.2 mmol) was added to a 7.06 (d, JH,H = 8 Hz, 2H, ArCH). 13C{1H} NMR (101 MHz,
2
solution of MeOH (90 μL, 2.2 mmol) in toluene (8 mL). This CD2Cl2): δC (ppm) 207.5 (m, Mo–CO), 204.0 (t, JC,P = 15 Hz,
reaction mixture was then added dropwise over 10 min to a Mo–CO), 144.8 (m, ArC), 135.5 (s, ArC), 128.1 (s, ArCH), 123.9
2
solution of 1b (0.250 g, 1.11 mmol) in toluene (10 mL) at (s, ArCH), 115.7 (d, JC,P = 16 Hz, ArCO), 112.8 (s, ArCH).
−78 °C. After 30 min at −78 °C, the reaction mixture was HR-MS (ESI): m/z calcd for C24H12F2MoO8P2 [M]+ = 625.9030;
passed through a short silica column and the silica was then obs. = 625.9006. IR (CH2Cl2): ν(CO) = 2066 cm−1
.
washed with toluene (3 × 10 mL). The volatiles were removed
cis-[Mo(CO)4(L7)2] (3c). Upon completion of the reaction,
under reduced pressure to yield the product as a white solid the volatiles were removed under reduced pressure. Hexane
(0.201 g, 82%). 31P{1H} NMR (162 MHz, C6D6): δP (ppm) 113.9 (5 mL) was added, and the reaction mixture was kept at −20 °C
(s). 31P{1H} data agreed with the literature data.32 31P NMR for 20 h. Once the product had precipitated, the supernatant
3
(162 MHz, C6D6): δP (ppm) 113.9 (q, JP,H = 12 Hz). 1H NMR was removed, and residual solvent removed under reduced
(400 MHz, C6D6): δH (ppm) 7.13 (d, JH,H = 8 Hz, 2H, ArCH), pressure from the solid to yield the product as a pale-yellow
6.99 (t, JH,H = 8 Hz, 2H, ArCH), 6.79 (d, JH,H = 8 Hz, 2H, ArCH), solid (0.0320 g, 71%). Crystals suitable for analysis by single
3
3.16 (d, JH,P = 12 Hz, 3H, O(CH3)). 13C{1H} NMR (101 MHz, crystal X-ray diffraction were grown by slow diffusion of hexane
C6D6): δC (ppm) 145.2 (d, 2JC,P = 4 Hz, ArCO), 135.5 (d, 3JC,P = 2 into
a
saturated CH2Cl2 solution of 3c. 31P{1H} NMR
1
Hz, ArC), 127.5 (s, ArCH), 122.3 (s, ArCH), 117.3 (m, ArC), (162 MHz, CD2Cl2): δP (ppm) 174.0 (dt, N = 1225 Hz, JP,F
=
2
2
4
3
112.1 (s, ArCH), 50.1 (d, JC,P = 13 Hz, O(CH3)). HR-MS 1227 Hz, JP,P′ = 49 Hz, JF,F′ = 0 Hz, JP,F′ = −2 Hz). 19F{1H}
This journal is © The Royal Society of Chemistry 2019
Dalton Trans.

View Article Online
Paper
Dalton Transactions
NMR (377 MHz, CD2Cl2): δF (ppm) −21.4 (dt, N = 1225 Hz, 1JF,P pitated with hexane (2 mL). The solid was allowed to settle,
2
4
3
1
= 1227 Hz, JP,P′ = 49 Hz, JF,F′ = 0 Hz, JF′,P = −2 Hz). H NMR and the supernatant was removed and remaining solid washed
(400 MHz, CD2Cl2): δH (ppm) 7.54 (d, JH,H = 8 Hz, 2H, ArCH), with hexane (3 × 1 mL). Residual solvent was removed under
7.41 (m, 4H, ArCH), 7.26 (d, JH,H = 8 Hz, 2H, ArCH). 13C{1H} reduced pressure to yield the product as a white solid
NMR (101 MHz, CD2Cl2): δC (ppm) 208.4 (m, Mo–CO), 204.9 (t, (0.0290 g, 84%). 31P{1H} NMR (162 MHz, d8-THF): δP (ppm)
2JC,P = 14 Hz, Mo–CO), 148.7 (m, ArC), 130.9 (s, ArCH), 130.4 118.0 (>99%, AA′3MXX′3, N = 1256 Hz, 1JP,Pt = 6102 Hz). 19F{1H}
(s, ArCH), 130.0 (s, ArC), 127.0 (s, ArCH), 122.5 (s, ArCH). NMR (377 MHz, d8-THF): δF (ppm) −7.2 (AA′3MXX′3). 31P{1H}
HR-MS (ESI): m/z calcd for C28H16F2MoNaO8P2 [M + Na]+
700.9241; obs. = 700.9240. IR (CH2Cl2): ν(CO) = 2059 cm−1
=
and 19F{1H} NMR data agreed with the literature data.17
[Pt(L7)4] (4c). Upon completion of the reaction, the volatiles
.
cis-[Mo(CO)4(L8)2] (3d). Upon completion of the reaction, were removed under reduced pressure. The product was preci-
the volatiles were removed under reduced pressure. The pitated with hexane (2 mL). The solid was allowed to settle,
product was triturated with hexane (2 mL). The solid was and the supernatant was removed and remaining solid washed
allowed to settle, and supernatant was removed; residual with hexane (3 × 1 mL). Residual solvent was removed under
solvent was removed from the solid under reduced pressure to reduced pressure to yield the product as an off-white solid
yield the product as a pale-yellow solid (0.0270 g, 48%). (0.0420 g, 88%). 31P{1H} NMR (162 MHz, d8-THF): δP (ppm)
1
Crystals suitable for analysis by single crystal X-ray diffraction 127.1 (AA′3MXX′3, N = 1181 Hz, JP,Pt = 6000 Hz, see ESI† for
were grown by slow diffusion of hexane into a saturated spectra). 19F{1H} NMR (377 MHz, d8-THF): δF (ppm) −23.9
CH2Cl2 solution of 3d. 31P{1H} NMR (162 MHz, CD2Cl2): δP (AA′3MXX′3). 195Pt{1H} NMR (65 MHz, d8-THF): δPt (ppm)
1
2
1
2
(ppm) 148.2 (dt, N = 1188 Hz, JP,F = 1189 Hz, JP,P′ = 49 Hz, −5637.8 (qq, JPt,P = 5999 Hz, JPt,F = 399 Hz). 1H NMR
4JF,F′ = 0 Hz, 3JP,F′ = −2 Hz). 19F{1H} NMR (377 MHz, CD2Cl2): δF (400 MHz, d8-THF): δH (ppm) 7.47 (dd, JH,H = 7, 2 Hz, 2H,
1
2
(ppm) −29.3 (dt, N = 1188 Hz, JF,P = 1189 Hz, JP,P′ = 49 Hz, ArCH), 7.24 (tt, JH,H = 7, 5 Hz, 4H, ArCH), 7.06 (m, 2H, ArCH).
4JF,F′ = 0 Hz, JF′,P = −2 Hz). 1H NMR (400 MHz, CD2Cl2): δH 13C{1H} NMR (101 MHz, d8-THF): δC (ppm) 149.9 (s, ArCO),
3
(ppm) 7.37 (d, JH,H = 7 Hz, 2H, ArCH), 7.22 (m, 4H, ArCH), 7.11 131.5 (s, ArC), 130.7 (s, ArCH), 130.3 (s, ArCH), 126.7 (s, ArCH),
2
(d, JH,H = 8 Hz, 2H, ArCH), 4.46 (d, JH,H = 14 Hz, 1H, CH2), 123.4 (s, ArCH). HR-MS (ESI): m/z calcd for C48H32F4NaO8P4Pt
2
3.70 (d, JH,H = 14 Hz, 1H, CH2). 13C{1H} NMR (101 MHz, [M + Na]+ = 1154.0528; obs. = 1154.0539.
CD2Cl2): δC (ppm) 208.3 (m, Mo–CO), 204.8 (m, Mo–CO), 149.4
[Pt(L8)4] (4d). Upon completion of the reaction, the volatiles
3
(m, ArCO), 132.4 (d, JC,P = 3 Hz, ArC), 131.2 (s, ArCH), 129.1 were removed under reduced pressure. The product was preci-
(s, ArCH), 126.9 (s, ArCH), 122.9 (d, JC,P = 3 Hz, ArCH), 35.0 (s, pitated with hexane (2 mL). The solid was allowed to settle,
CH2). HR-MS (ESI): m/z calcd for C30H20F2MoNaO8P2 [M + Na]+ and the supernatant was removed and remaining solid washed
= 728.9555; obs. = 728.9550. IR (CH2Cl2): ν(CO) = 2058 cm−1
.
with hexane (3 × 1 mL). Residual solvent was removed under
cis-[Mo(CO)4(L6a)2] (3e). Upon completion of the reaction, reduced pressure to yield the product as an off-white solid
the volatiles were removed under reduced pressure. The (0.0380 g, 85%). 31P{1H} NMR (162 MHz, d8-THF): δP (ppm)
1
product was triturated with hexane (2 mL). The solid was 155.6 (AA′MXX′, 6d), 105.7 (AA′3MXX′3, N = 1132 Hz, JP,Pt
=
allowed to settle, and supernatant was removed; residual 5981 Hz, 4d, >93%). 19F{1H} NMR (377 MHz, d8-THF): δF
solvent was removed from the solid under reduced pressure to (ppm) −27.8 (AA′3MXX′3, 4d, >93%), −43.9 (AA′MXX′, 6d). 195Pt
1
yield the product as a white solid (0.0290 g, 67%). Crystals suit- {1H} NMR (65 MHz, d8-THF): δPt (ppm) −5281.9 (tt, JPt,P
=
2
1
able for analysis by single crystal X-ray diffraction were grown 6107 Hz, JPt,F = 454 Hz, 6d), −5638.4 (qq, JPt,P = 5983 Hz,
by storing a saturated pentane solution of 3e. 31P{1H} NMR 2JPt,F = 354 Hz, 4d). 1H NMR (400 MHz, d8-THF): δH (ppm)
(162 MHz, CD2Cl2): δP (ppm) 151.1 (s). 31P NMR (162 MHz, 7.29 (d, JH,H = 7 Hz, 2H, ArCH), 7.15 (t, JH,H = 7 Hz, 2H, ArCH),
1
CD2Cl2): δP (ppm) 151.1 (m). H NMR (400 MHz, CD2Cl2): δH 7.05 (t, JH,H = 7 Hz, 2H, ArCH), 6.91 (d, JH,H = 8 Hz, 2H, ArCH),
2
2
(ppm) 7.55 (d, JH,H = 8 Hz, 2H, ArCH), 7.39 (t, JH,H = 8 Hz, 2H, 4.27 (d, JH,H = 14 Hz, 1H, CH2), 3.63 (d, JH,H = 14 Hz, 1H,
ArCH), 6.92 (d, JH,H = 8 Hz, 2H, ArCH), 3.68 (m, 3H, O(CH3)). CH2). 13C{1H} NMR (101 MHz, d8-THF): δC (ppm) 150.5 (s,
13C{1H} NMR (101 MHz, CD2Cl2): δC (ppm) 210.2 (m, Mo–CO), ArCO), 133.4 (s, ArC), 131.3 (s, ArCH), 128.8 (s, ArCH), 126.3 (s,
2
206.1 (t, JC,P = 14 Hz, Mo–CO), 146.0 (s, ArC), 135.5 (s, ArC), ArCH), 123.8 (s, ArCH), 35.7 (s, CH2). HR-MS (ESI): m/z calcd
128.0 (s, ArCH), 123.1 (s, ArCH), 116.0 (s, ArC), 112.5 (s, ArCH), for C52H40F4NaO8P4Pt [M
52.7 (s, O(CH3)). HR-MS (ESI): m/z calcd for C24H19MoO8P2 1210.1160.
+ = 1210.1154; obs. =
Na]+
[M − (CO)2 + H]+ = 594.9615; obs. = 594.9614. IR (CH2Cl2):
[Pt(L6a)4] (4e). Upon completion of the reaction, the vola-
tiles were removed under reduced pressure and the crude
product was dissolved in toluene (1 mL) and the solvent
removed under reduced pressure to yield the product as a
ν(CO) = 2051 cm−1
.
Pt(0) complexes: General procedure for synthesis of [PtL4]
complexes 4a,c–e
white solid (0.0430 g, 96%). 31P{1H} NMR (162 MHz, d8-THF):
1
To a solution of [Pt(nbe)3] (0.0200 g, 0.042 mmol) in THF δP (ppm) 110.1 (s, JP,Pt = 5745 Hz). 31P NMR (162 MHz, d8-
(0.5 mL) was added a solution of the ligand (0.168 mmol) in THF): δP (ppm) 110.1 (m, JP,Pt = 5745 Hz). 195Pt{1H} NMR
1
1
1
THF (0.5 mL).
(65 MHz, d8-THF): δPt (ppm) −5678.5 (q, JPt,P = 5746 Hz). H
[Pt(L5)4] (4a). Upon completion of the reaction, the volatiles NMR (400 MHz, d8-THF): δH (ppm) 7.48 (d, JH,H = 8 Hz, 2H,
were removed under reduced pressure. The product was preci- ArCH), 7.35 (t, JH,H = 8 Hz, 2H, ArCH), 6.93 (d, JH,H = 8 Hz, 2H,
Dalton Trans.
This journal is © The Royal Society of Chemistry 2019

View Article Online
Dalton Transactions
Paper
2
ArCH), 3.65 (m, 3H, O(CH3)). 13C{1H} NMR (101 MHz, d8-THF): Hz, JPt,F
=
567 Hz, 7d). HR-MS (ESI): m/z calcd for
δC (ppm) 147.6 (s, ArCO), 136.2 (s, ArC), 128.1 (s, ArCH), 122.6 C33H31O4PtF2P2 (6d) [M + H]+ = 786.1320; obs. = 786.1313.
(s, ArCH), 177.4 (s, ArC), 112.6 (s, ArCH), 52.9 (s, O(CH3)).
Reaction with L6a. 31P{1H} NMR (122 MHz, d8-THF): δP
(ppm) 147.5 (s, 1JP,Pt = 5941 Hz, 53%, 6e), 136.0 (s, 1JP,Pt = 5895
HR-MS (ESI): m/z calcd for C44H36NaO12P4Pt [M + Na]+
=
1
1098.0701; obs. = 1098.0690.
Hz, 12%, 7e), 108.2 (s, JP,Pt = 5744 Hz, 35%, 4e). 195Pt{1H}
1
Synthesis of [Pt(L6)4] (4b).
A
chlorobenzene solution NMR (65 MHz, d8-THF): δPt (ppm) −5255.0 (t, JPt,P = 5942 Hz,
(1.5 mL) of [Pt(nbe)3] (0.0150 g, 0.0314 mmol) was layered with 6e), −5685.7 (q, JPt,P = 5744 Hz, 4e), −5707.5 (d, JPt,P = 5902
chlorobenzene solution (1.5 mL) of L6 (0.0226 g, Hz, 7e).
1
1
a
0.126 mmol). The mixture was left to stand and within 48 h,
crystals of 4b suitable for X-ray crystallography were obtained.
General procedure for the NMR study of the reaction
Rh(I) complexes
Synthesis of [RhCl(L5)2]2 (8a). To a solution of [RhCl(CO)2]2
between ligand and [Pt(nbe)3] in a 2 : 1 stoichiometry. To a (0.0200 g, 0.0514 mmol) in C6D6 (0.5 mL) was added a solution
solution of [Pt(nbe)3] (0.0200 g, 0.0419 mmol) in THF (0.5 mL) of L5 (0.0160 g, 0.103 mmol) in C6D6 (0.5 mL). After 2 h, the
was added a solution of the ligand (0.0838 mmol) in THF reaction mixture was saturated with N2 by three successive
(0.5 mL). The reaction mixture was monitored by in situ 31P freeze–pump–thaw cycles to give an orange solution. 31P{1H}
1
{1H}, 19F{1H} and 195Pt{1H} NMR spectroscopy (see ESI† for NMR (162 MHz, C6D6): δP (ppm) 134.8 (br. d, JP,F = 1323 Hz).
1
analysis of the spectra).
19F{1H} NMR (377 MHz, C6D6): δF (ppm) −9.5 (br. d, JF,P
=
Reaction with L5. 31P{1H} NMR (162 MHz, d8-THF): δP (ppm) 1314 Hz). 31P{1H} and 19F{1H} NMR data fitted with the litera-
1
167.2 (br. AA′MXX′, N = 1281 Hz, 16%, 6a), 157.6 (d, JP,F
=
ture data.18
1
1337 Hz, JP,Pt = 6314 Hz, 7%, 7a), 118.0 (AA′3MXX′3, N = 1256
General procedure for the NMR study of the reaction
Hz, JP,Pt = 6102 Hz, 77%, 4a). 19F{1H} NMR (377 MHz, d8- between ligands L6–8 or L6a and [RhCl(CO)2]2 in a 4 : 1 stoi-
1
THF): δF (ppm) −7.3 (AA′3MXX′3, 4a), −22.8 (br. AA′MXX′, N = chiometry. To
a
solution of [RhCl(CO)2]2 (0.0150 g,
1281 Hz, 6a), −23.2 (d, 1JF,P = 1337 Hz, 2JF,Pt = 714 Hz, 7a). 195Pt 0.0386 mmol) in CH2Cl2 (0.5 mL) was added a solution of the
1
{1H} NMR (65 MHz, d8-THF): δPt (ppm) −5571.9 (qq, JPt,P
=
ligand (0.154 mmol) in CH2Cl2 (0.5 mL). After 2 h, the reaction
2
1
6098 Hz, JPt,F = 445 Hz, 4a), −5688.8 (dd, JPt,P = 6314 Hz, mixture was saturated with N2 by three successive freeze–
2JPt,F = 716 Hz, 7a). pump–thaw cycles. See ESI† for 31P{1H} and 19F{1H} NMR
Reaction with L6. Immediately an insoluble precipitate spectra.
formed (assumed to be 4b), the following was observed in the
[RhCl(L6)2]2 (8b)/[Rh(L6)5][Cl] (9b). 31P{1H} NMR (162 MHz,
filtrate: 31P{1H} NMR (162 MHz, d8-THF): δP (ppm) 140.0 (AA′ CD2Cl2): δP (ppm) 113.0 (AA′4MM′4X, ≈20%, 9b), 112.6 (br. d,
MXX′, N = 1238 Hz, 1JP,F = 1271 Hz, 2JP,P′ = 182 Hz, 4JF,F′ = 0 Hz, 1JP,F = 1354 Hz, ≈80%, 8b). 19F{1H} NMR (377 MHz, CD2Cl2): δF
3JP,F′ = −34 Hz, JP,Pt = 6525 Hz, 23%, 6b), 129.2 (d, JP,F = 1268 (ppm) −19.5 (AA′4MM′4X, 9b), −30.1 (br. d, 8b). HR-MS (nano-
1
1
Hz, JP,Pt = 6423 Hz, 77%, 7b). 19F{1H} NMR (377 MHz, d8- spray): m/z calcd for C50H30F5O10P5Rh [9b–Cl]+ = 1142.95;
1
1
THF): δF (ppm) −37.6 (AA′MXX′, N = 1238 Hz, JF,P = 1271 Hz, obs. = 1143.03.
2JP,P′ = 182 Hz, JF,F′ = 0 Hz, JF′,P = −34 Hz, JF,Pt = 593 Hz, 6b),
[RhCl(L7)2]2 (8c)/[Rh(L7)5][Cl] (9c)/trans-[RhCl(CO)(L7)2]
4
3
2
−39.3 (d, JF,P = 1268 Hz, JF,Pt = 611 Hz, 7b). 195Pt{1H} NMR (10c). 31P{1H} NMR (162 MHz, CD2Cl2): δP (ppm) 144.4
1
2
(65 MHz, d8-THF): δPt (ppm) −5224.3 (tt, JPt,P = 6521 Hz, JPt,F (AA′4MM′4X, 9c), 129.1 (br. d, 1JP,F = 1260 Hz, 8c). 19F{1H} NMR
1
1
1
2
= 597 Hz, 6b), −5687.2 (dd, JPt,P = 6424 Hz, JPt,F = 613 Hz, (377 MHz, CD2Cl2): δF (ppm) −19.1 (AA′4MM′4X, ≈18%, 9c),
1
1
7b).
−31.1 (br. d, ≈15%, JF,P = 1152 Hz, 10c), −44.1 (br. d, JF,P =
Reaction with L7. 31P{1H} NMR (162 MHz, THF): δP (ppm) 1152 Hz, ≈67%, 8c). HR-MS (ESI): m/z calcd for
167.8 (AA′MXX′, N = 1267 Hz, JP,F = 1293 Hz, JP,P′ = 167 Hz, C60H40F5O10P5Rh [9c–Cl]+ = 1273.0279; obs. = 1273.0287. IR
1
2
4JF,F′ = 5 Hz, 3JP,F′ = −26 Hz, 1JP,Pt = 6275 Hz, 44%, 6c), 156.4 (d, (CH2Cl2): ν(CO) of 10c = 2032 cm−1
.
1JP,F = 1291 Hz, JP,Pt = 6215 Hz, 16%, 7c), 127.1 (AA′3MXX′3,
[RhCl(L8)2]2 (8d)/[Rh(L8)5][Cl] (9d)/trans-[RhCl(CO)(L8)2]
1
N = 1181 Hz, JP,Pt = 6000 Hz, 40%, 4c). 19F{1H} NMR (10d). 31P{1H} NMR (162 MHz, CD2Cl2): δP (ppm) 115.6
1
1
(377 MHz, THF): δF (ppm) −23.9 (AA′3MXX′3, 4c), −37.5 (AA′4MM′4X, ≈30%, 9d) 108.8 (br. d, JP,F = 1211 Hz, ≈70%,
1
2
4
(AA′MXX′, N = 1267 Hz, JF,P = 1293 Hz, JP,P′ = 167 Hz, JF,F′
=
=
8d). 19F{1H} NMR (377 MHz, CD2Cl2): δF (ppm) −36.5
3
2
1
1
5 Hz, JF′,P = −26 Hz, JF,Pt = 596 Hz, 6c), −39.1 (d, JF,P
1291 Hz, 2JF,Pt = 323 Hz, 7c).
(AA′4MM′4X, ≈23%, 9d), −38.3 (d, JF,P = 1223 Hz, ≈4%, 10d),
1
−52.3 (br. d, JF,P = 1205 Hz, ≈73%, 8d). HR-MS (ESI): m/z
Reaction with L8. 31P{1H} NMR (162 MHz, d8-THF): δP (ppm) calcd for C65H50F5O10P5Rh [9d–Cl]+ = 1343.1062; obs. =
155.4 (AA′MXX′, N = 1212 Hz, JP,F = 1224 Hz, JP,P′ = 147 Hz, 1343.1135. IR (CH2Cl2): ν(CO) of 10d = 2028 cm−1
.
1
2
4JF,F′ = 0 Hz, JP,F′ = −12 Hz, JP,Pt = 6115 Hz, 6d), 141.6 (d, JP,F
[Rh(L6a)5][Cl] (9e)/trans-[RhCl(CO)(L6a)2] (10e). 31P{1H}
3
1
1
= 1224 Hz, JP,Pt = 6253 Hz, 7d). 19F{1H} NMR (377 MHz, d8- NMR (122 MHz, CH2Cl2): δP (ppm) 122.6 (d, JP,Rh = 127 Hz,
1
1
1
1
THF): δF (ppm) −27.8 (AA′3MXX′3, 6%, 4d), −43.8 (AA′MXX′, 28%, 9e), 119.8 (d, JP,Rh = 181 Hz, 2%), 113.1 (d, JP,Rh = 210
N = 1212 Hz, 1JF,P = 1224 Hz, 2JP,P′ = 147 Hz, 4JF,F′ = 0 Hz, 3JF′,P Hz, 70%, 10e). IR (CH2Cl2): ν(CO) of 10e = 2023 cm−1
−12 Hz, 2JF,Pt = 454 Hz, 91%, 6d), −45.2 (d, 1JF,P = 1223 Hz, 3%,
Synthesis of [RhCl(L6)2]2 (8b). To a solution of [RhCl(cod)]2
7d). 195Pt{1H} NMR (65 MHz, d8-THF): δPt (ppm) −5282.0 (tt, (0.0200 g, 0.0406 mmol) in CH2Cl2 (0.5 mL) was added a solu-
=
.
2
1
1JPt,P = 6110 Hz, JPt,F = 454 Hz, 6d), −5751.7 (dd, JPt,P = 6252 tion of L6 (0.0337 g, 0.162 mmol) in CH2Cl2 (0.5 mL). Upon
This journal is © The Royal Society of Chemistry 2019
Dalton Trans.

View Article Online
Paper
Dalton Transactions
completion of the reaction, the volatiles were removed under
reduced pressure. The product was precipitated with hexane
(2 mL). The solid was allowed to settle, and the supernatant
was removed and remaining solid washed with hexane (3 ×
1 mL). Residual solvent was removed under reduced pressure
to yield the product as an orange solid. 31P{1H} NMR
4 (a) C. A. Tolman, Chem. Rev., 1977, 77, 313–348;
(b) D. Setiawan, R. Kalescky, E. Kraka and D. Cremer, Inorg.
Chem., 2016, 55, 2332–2344.
5 (a) E. Billig, A. G. Abatjoglou and D. R. Bryant, US Patent,
4668651, 1987; (b) E. Billig, A. G. Abatjoglou and D. R. Bryant,
US Patent, 4748261, 1988; (c) E. Billig, A. G. Abatjoglou and
D. R. Bryant, US Patent, 4885401, 1989.
(162 MHz, CD2Cl2): δP (ppm) 108.2 (dd, 1JP,F = 1222 Hz, 1JP,Rh
328 Hz). 19F{1H} NMR (377 MHz, CD2Cl2): δF (ppm) −30.8 (d,
1JF,P
1232 Hz). HR-MS (nanospray): m/z calcd for
C40H23ClF4O8P4Rh2 [M − Cl]+ = 1072.8157; obs. = 1072.8163.
Synthesis of [Rh(L6)5][BF4] (9b′). To solution of
=
6 For leading references see: (a) P. C. J. Kamer, J. N. H. Reek
and P. W. N. M. van Leeuwen, in Rhodium catalysed hydro-
formylation, ed. P. W. N. M. van Leeuwen and C. Claver,
Springer, 1982, ch. 3; (b) P. W. N. M. van Leeuwen, in
Homogeneous Catalysis, Understanding the Art, Springer,
2004, ch. 8; (c) A. Börner and R. Franke in
Hydroformylation: Fundamentals, Processes, and Applications
in Organic Synthesis, vol. 2, Wiley, 2016; (d) R. Franke,
D. Franke and A. Börner, Chem. Rev., 2012, 112, 5675–5732.
7 (a) M. J. Baker, K. N. Harrison, A. G. Orpen, P. G. Pringle
and G. Shaw, J. Chem. Soc., Chem. Commun., 1991, 803–804;
(b) M. J. Baker and P. G. Pringle, J. Chem. Soc., Chem.
Commun., 1991, 18, 1292–1293; (c) T. Foo, J. Garner,
R. Shapero and W. Tam, World Patent, 9622968, 1996 to
DuPont; (d) K. A. Kreutzer and W. Tam, World Patent,
95028228, 1995 to DuPont; (e) K. A. Kreutzer and W. Tam,
US Patent, 5663369, 1997 to DuPont. ; (f) L. Bini, C. Muller
and D. Vogt, ChemCatChem, 2010, 2, 590–608; (g) L. Bini,
C. Muller and D. Vogt, Chem. Commun., 2010, 46, 8325–8334.
8 For leading references see: (a) M. Reetz, Angew. Chem., Int.
Ed., 2008, 47, 2556–2588; (b) P. W. N. M. van Leeuwen,
P. C. J. Kamer, C. Claver, O. Pàmies and M. Diéguez, Chem.
Rev., 2011, 111, 2077–2118; (c) H. Fernández-Pérez,
P. Etayo, A. Panossian and A. Vidal-Ferran, Chem. Rev.,
2011, 111, 2119–2176; (d) K. Takahashi, M. Yamashita,
Y. Tanaka and K. Nozaki, Angew. Chem., Int. Ed., 2012, 51,
4283–4387; (e) L. Iu, J. A. Fuentes, M. E. Janka,
K. J. Fontenot and M. L. Clarke, Angew. Chem., Int. Ed.,
2019, 58, 2120–2124.
9 (a) M. van den Berg, A. J. Minnaard, R. M. Haak,
M. Leeman, E. P. Schudde, A. Meetsma, B. L. Feringa,
A. H. M. de Vries, C. E. P. Maljaars, C. E. Willans, D. Hyett,
J. A. F. Boogers, H. J. W. Henderickx and J. G. de Vries, Adv.
Synth. Catal., 2003, 345, 308–323; (b) J. F. Teichert and
B. L. Feringa, Angew. Chem., Int. Ed., 2010, 49, 2486–2528.
10 (a) A. P. V. Göthlich, M. Tensfeldt, H. Rothfuss,
M. E. Tauchert, D. Haap, F. Rominger and P. Hofmann,
Organometallics, 2008, 27, 2189–2200; (b) C. Claver,
E. Fernandez, A. Gillon, K. Heslop, D. J. Hyett, A. Martorell,
A. G. Orpen and P. G. Pringle, Chem. Commun., 2000, 961–
962; (c) M. M. Pereira, M. J. F. Calvete, R. M. B. Carrilho
and A. R. Abreu, Chem. Soc. Rev., 2013, 6990–7027.
=
a
[Rh(cod)2][BF4] (0.0150 g, 0.0369 mmol) in CH2Cl2 (0.5 mL)
was added a solution of L6 (0.0380 g, 0.185 mmol) in CH2Cl2
(0.5 mL). Upon completion of the reaction, the volatiles were
removed under reduced pressure. The product was precipitated
with hexane (2 mL). The solid was allowed to settle, and the
supernatant was removed and remaining solid washed with
hexane (3 × 1 mL). Residual solvent was removed under
reduced pressure to yield the product as a pale green solid
(0.0390 g, 65%). 31P{1H} NMR (162 MHz, CD2Cl2): δP (ppm)
1
118.5 (AA′4MM′4X, JP,F = 1286 Hz). 19F{1H} NMR (377 MHz,
CD2Cl2): δF (ppm) −19.4 (AA′4MM′4X, 5F, [Rh(L6)5][BF4]),
−153.2 (2 s, 4F, 4 : 1 [11BF4] : [10BF4]). 1H NMR (400 MHz,
CD2Cl2): δH (ppm) 7.74 (d, JH,H = 8 Hz, 2H, ArCH), 7.50 (t,
JH,H = 8 Hz, 2H, ArCH), 7.03 (d, JH,H = 8 Hz, 2H, ArCH). 13C{1H}
NMR (101 MHz, CD2Cl2): δC (ppm) 143.9 (s, ArCO), 135.6 (s,
ArC), 128.4 (s, ArCH), 125.3 (s, ArCH), 114.8 (m, ArC), 113.4 (s,
ArCH). HR-MS (ESI): m/z calcd for C50H30F5O10P5Rh [M − BF4]+
= 1142.9497; obs. = 1142.9483.
Conflicts of interest
There are no conflicts of interest to declare.
Acknowledgements
We thank the following for PhD studentships: EPSRC (to
AMH) and the Bristol Chemical Synthesis Centre for Doctoral
Training (BCS CDT) funded by the Engineering and Physical
Sciences Research Council (EPSRC) (EP/L015366/1) (to EH).
References
1 (a) T. Kruck, Angew. Chem., Int. Ed. Engl., 1967, 6, 53–67;
(b) J. F. Nixon and J. R. Swain, Platinum Met. Rev., 1975, 19,
22–29 and references therein.
2 (a) P. Kündig, M. Moskovits and G. A. Ozin, J. Mol. Struct.,
1972, 14, 137–144; (b) P. Doz, T. Kruck and K. Baur, Angew. 11 (a) T. A. Puckette, Chem. Ind., 2007, 115, 31–38; (b) Y.-S. Liu
Chem., Int. Ed. Engl., 1965, 4, 521; (c) P. Doz, T. Kruck and
K. Baur, Angew. Chem., 1965, 77, 505–506; (d) H. Huber,
P. Kündig, M. Moskovits and G. A. Ozin, Nat. Phys. Sci.,
1972, 235, 98–100.
3 J. F. Nixon, Adv. Inorg. Chem. Radiochem., 1985, 29, 41–141
and references therein.
and J. L. Rodger, US Patent, 20090171121, 2009 to Eastman;
(c) T. A. Puckette and Y.-S. Liu, World Patent, 2010151285,
2010 to Eastman.
12 E. Billig, A. G. Abatjoglou and D. R. Bryant, European
Patent, EP0213639, 1987 to Union Carbide.
13 R. Schmutzler, Chem. Ber., 1963, 96, 2435–2450.
Dalton Trans.
This journal is © The Royal Society of Chemistry 2019

View Article Online
Dalton Transactions
Paper
14 (a) P. P. Onys’ko, T. V. Kolodka and A. D. Sinitsa, 23 (a) A. G. Orpen and N. G. Connelly, J. Chem. Soc., Chem.
Russ. J. Gen. Chem., 1993, 63, 1556–1559; (b) O. Farooq,
New J. Chem., 2000, 24, 81–84; (c) D. J. St-Cyr, M. S. Morin,
F. B. Belanger-Gariepy, B. A. Arndtsen, E. H. Krenske and
K. N. Houk, J. Org. Chem., 2010, 75, 4261–4273.
Commun., 1985, 1310–1311; (b) A. G. Orpen and
N. G. Connelly, Organometallics, 1990, 9, 1206;
(c) M. F. Haddow, A. J. Middleton, A. G. Orpen,
P. G. Pringle and R. Papp, Dalton Trans., 2009, 202–209.
15 T. G. Meyer, A. Fischer, P. G. Jones and R. Schmutzler, 24 I. A. Guzei and M. Wendt, Dalton Trans., 2006, 3991–
Z. Naturforsch., B: J. Chem. Sci., 1993, 48, 659–671. 3999.
16 (a) G. S. Reddy and R. Schmutzler, Phosphorus-Fluorine 25 C. J. Cobley and P. G. Pringle, Inorg. Chim. Acta, 1997, 265,
Chem., 1967, 6, 823–830; (b) R. K. Harris, J. R. Woplin and 107–115.
R. Schmutzler, Ber. Bunseng. Phys. Chem., 1971, 75, 134– 26 J. F. Nixon and J. R. Swain, J. Chem. Soc., Dalton Trans.,
140; (c) R. Schmutzler, Chem. Ber., 1963, 96, 2435–2450. 1972, 1044–1048.
17 (a) C. Crocker and R. J. Goodfellow, J. Chem. Soc., Dalton 27 (a) M. J. Atherton, K. S. Coleman, J. Fawcett, J. H. Holloway,
Trans., 1977, 1687–1689; (b) C. Crocker and R. J. Goodfellow,
J. Chem. Res., Synop., 1981, 2, 36–39; (c) R. M. Matos,
R. F. F. Da Costa, V. F. Knupp, J. André, D. Silva and
B. F. T. Passos, J. Braz. Chem. Soc., 2000, 11, 311–316.
18 P. B. Hitchcock, S. Morton and J. F. Nixon, J. Chem. Soc.,
Dalton Trans., 1985, 1295–1301.
E. G. Hope, A. Karaçar, L. A. Peck and G. C. Saunders,
J. Chem. Soc., Dalton Trans., 1972, 4029–4037;
(b) T. Korenaga, K. Osaki, R. Maenishi and T. Sakai, Org.
Lett., 2009, 11, 2325–2328; (c) T. Korenaga, A. Ko,
K. Uotani, Y. Tanaka and T. Sakai, Angew. Chem., Int. Ed.,
2011, 50, 10703–10707.
19 A. Gual, C. Godard, V. de la Fuente and S. Castillón, in 28 J. J. C. Van Lier, R. J. M. Hermans and H. M. Buck,
Phosphorus(III) Ligands in Homogeneous Catalysis, John
Wiley & Sons, Ltd., 2012, pp. 81–131.
20 M. Moghadam, S. Tangestaninejad, V. Mirkhani,
Phosphorus Sulfur Relat. Elem., 1984, 19, 173–188.
29 S. Wagner, M. Rakotomalala, Y. Bykov, O. Walter and
M. Doring, Heteroat. Chem., 2012, 25, 216–222.
I. Mohammadpoor-Baltork and S. Gharaati, Appl. 30 J. Coetzee, G. R. Eastham, A. M. Z. Slawin and D. J. Cole-
Organomet. Chem., 2009, 23, 446–454. Hamilton, Org. Biomol. Chem., 2012, 10, 3677–3688.
21 I. Neda, A. Fischer, T. Kaukorat, P. G. Jones and 31 J. Gloede, U. Pieper and W. D. Habicher, Z. Anorg. Allg.
R. Schmutzler, Chem. Ber., 1994, 127, 1579–1586. Chem., 2002, 628, 877.
22 D. R. Anton and R. H. Crabtree, Organometallics, 1983, 2, 32 L. M. Voropai, N. G. Ruchkina, E. E. Milliaresi and
621–627.
E. E. Nifant’ev, J. Gen. Chem. USSR, 1985, 55, 55–62.
This journal is © The Royal Society of Chemistry 2019
Dalton Trans.