Synthesis and structure of novel [Ph(RO)PSe2] complexes

Article abstract of DOI:10.1039/b503793j

Reaction of (PhPSe₂)₂ (Woollins reagent) with NaOR (R = Me, Et, ⁱPr) gives the non-symmetric phosphonodiselenoato anions [Ph(RO)PSe₂]^- which can be complexed to a range of metals. The nickel complex N

Full text of DOI:10.1039/b503793j

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F U L L P A P E R
Synthesis and structure of novel [Ph(RO)PSe2]− complexes
Ian P. Gray, Alexandra M. Z. Slawin and J. Derek Woollins*
School of Chemistry, University of St Andrews, St Andrews, Fife, UK KY16 9ST.
E-mail: jdw3@st-and.ac.uk
Received 14th March 2005, Accepted 5th May 2005
First published as an Advance Article on the web 17th May 2005
Reaction of (PhPSe2)2 (Woollins reagent) with NaOR (R = Me, Et, iPr) gives the non-symmetric
phosphonodiselenoato anions [Ph(RO)PSe2]− which can be complexed to a range of metals. The nickel complex
Ni[Ph(MeO)PSe2]2 adopts a square-planar ML2 structure while the cadmium complex Cd[Ph(MeO)PSe2]2 displays a
dimeric M2L4 structure. Two different lead complexes are observed, one consisting of PbL2 units joined by Pb · · · Se
interactions to form distinct dimeric pairs. The other displays a novel dimeric structure built around a central
four-membered Pb2Se2 ring. All new compounds have been characterised spectroscopically (31P, 1H, 13C NMR, IR,
mass spectroscopy), by elemental analysis and five demonstrative X-ray structures are reported.
data and crystallographic studies of a range of silver and
Introduction
copper containing cluster compounds incorporating dialkyl
A large number of examples have been reported showing that
phosphorodiselenoate ligands.24–30
the ring structure of Lawesson’s reagent and other dithiadipho-
Here we report the synthesis of sodium phosphonodiselenoate
sphetane disulfides can be cleaved leading to the formation of
salts achieved via a ring-opening reaction of WR. Novel Ni, Pd,
Pt, Zn, Cd, Hg, Sn and Pb phosphonoselenoate complexes have
phosphorus–sulfur containing metal complexes,1–7 the same can
not be said for their known selenium counterparts.
been synthesised and studied by IR, mass spectroscopy, multin-
(PhPSe2)2 (Woollins reagent, WR) has been shown to act
uclear NMR and in several cases by X-ray crystallography. To
as an efficient selenium transfer reagent for the synthesis of a
the best of our knowledge this is the first reported synthesis of
range of selenoamides and selenoaldehydes by means of a simple
phosphonodiselenoate ligands and their complexes and provides
O/Se exchange reaction.8,9 It has also been reported to undergo
a valuable addition to the few examples of phosphodiselenoate
reactions with a variety of reactive organic substrates including
ligands known.
CS2,10 acetone,10 C C double bonds,
C≡C triple bonds,14
11–13
=
unsaturated carbon–nitrogen compounds,15 catechol and other
dibasic nucleophiles16 yielding a wide range of phosphorus–
selenium heterocycles.
Results and discussion
The phosphonodiselenoate salts 1–3 were prepared by the
reaction of WR with 2 molar equivalents of sodium alkoxide
(Scheme 1).
The metal complexation of WR has been less well docu-
mented. The reaction of WR with cis-PtCl2(PR3)2 (PR3 = 1/2
dppe, PEt3, PMe2Ph and PPh2Me) in THF yielded the complexes
cis-Pt(Se3PPh)(PR3)2.17 Baxter et al. used WR to selenate
2
the carbonyl containing complexes [ML(g -OCCR)(CO)(Tp)]
(M = W, Mo; L = PMe2Ph, PPh3, P(OMe)3; R = anisyl;
Tp = hydrotris(pyrazol-1-yl)borate) in the synthesis of the
2
selenoketenyl complexes [ML(g -SeCCR)(CO)(Tp)].18
There have been a number of reports of the synthesis and com-
plexation of phosphinodiselenoate and phosphorodiselenooate
ligands dating back to 1964, complexes with a wide range of
metals were reported but unfortunately very little experimental
or spectroscopic data was made available.19,20 Modern studies
of alkali metal complexes of such phosphinodiselenoate and
related selenophosphorus ligands was conducted by Davies and
co-workers,21 including the first reported example of solvated
lithium salts of a selenophosphinite anion. Two zinc complexes
containing phosphoroselenoate moieties, [Zn{Se2P(OEt)}2]n
and [Zn2{Se2P(OiPr)2}4], were reported by Santra et al.,22 these
were studied crystallographically displaying a one-dimensional
helical chain structure and a dimeric motif containing an eight-
membered P2Se4Zn2 central ring, respectively. The complexes
were also characterised by multinuclear NMR and variable tem-
perature 31P NMR revealing their behaviour in the solution state.
Another modern application of dialkyl phosphorodiselenoate
ligands is in the field of metal cluster chemistry. In 1998
Liu and co-workers23 reported the first discrete CuI8 cubic
cluster, {Cu8(l8-Se)[Se2P(OiPr)2]6} in which each face of the
cube is bridged by a diisopropyl phosphorodiselenoate ligand
and has an interstitial selenide ion (Se2−). Since the release
of this report, Liu and co-workers have published no fewer
than seven further reports detailing the synthesis, spectroscopic
Scheme 1
Cleavage of the four-membered P2Se2 ring in WR generates
the sodium phosphonodiselenoate salts 1–3 in high yield as
either white or pale yellow solids. which are soluble in polar
solvents such as alcohols and acetone but are insoluble in less
polar solvents. 1–3 are unstable to air and moisture, obvious
signs of degradation occur within minutes of exposure including
reddening of the powders due to the expulsion of elemental
selenium and the evolution of foul smelling gas. The 31P NMR
spectra of 1–3 displayed sharp singlets at d(P) 83.0, 78.8 and
75.6 ppm, respectively. In each case the singlet was accompanied
by a single pair of selenium satellites with 31P–77Se coupling
constants in the range 667–675 Hz, indicating a P–Se bond order
of approximately 1.5 as expected. This was further substantiated
by the 77Se NMR spectra which displayed doublets at d(Se)
60.8, 71.1 and 87.4 ppm, respectively with matching 31P–77Se
coupling constants. The H and 13C NMR spectra of 1–3 were
as expected confirming the presence of the phenyl and alkoxy
moieties. The IR spectra show bands at 1179–1170, 1028–1015,
1
2 1 8 8
D a l t o n T r a n s . , 2 0 0 5 , 2 1 8 8 – 2 1 9 4
T h i s j o u r n a l i s
T h e R o y a l S o c i e t y o f C h e m i s t r y 2 0 0 5
©

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542–518 and 502–499 cm−1 corresponding to m[(P)–O–C], m[P–
O–(C)], m(PSe)asym and m(PSe)sym absorptions, respectively.31 Mass
spectrometry showed the expected parent ions as (M − Na)+ at
m/z 299, 313 and 325. The microanalyses of 1–3 were poor,
and we speculate that this is a consequence of decomposition to
elemental selenium, however the purity of the salts was deemed
satisfactory for use in further reactions.
Three examples of related alkali metal phosphinodiselenoate
complexes have been structurally characterised. Na2[Ph2PSe2]2·
THF·5H2O consists of a central polymeric core built up of
Na(H2O)6 and Na(H2O)3(THF)(Se) units with additional
hydrogen-bonded [Ph2PSe2]− anions.32 [K(Ph2PSe2)(THF)2]2
exists as discrete centrosymmetric dimers with a central
K2P2Se4 cage bound by phenyl and THF units.21 [Ph2PSe2-
Li(THF)(TMEDA)] exhibits a simple monomeric structure with
the lithium cation coordinated asymmetrically by one THF and
one TMEDA molecule.21
All attempts to crystallise salts 1–3 proved unsuccessful, how-
ever in one such attempt “wet” solvents were used and despite
degradation occurring, a small amount of colourless crystals
suitable for X-ray analysis were obtained. The structure was
elucidated and assigned as 4, a product of hydrolytic degradation
(Fig. 1, Table 1). The X-ray structure of 4 illustrates that the salt
3 has been converted to [(Ph){OiPr}PSeONa]4(H2O)4, with one
of the sodium bound selenium atoms of 3 having been replaced
by an oxygen atom. This compound exhibits a very different
structural motif to the above examples. The structure consists
of four ligands joined together in a cubane-like structure. The
sodium and oxygen atoms are arranged as two interpenetrating
tetrahedra to give the overall cubic structure. The sodium atoms
are each bound to a single water molecule resulting in an
approximate trigonal-bipyramidal geometry.
Fig. 1 The X-ray crystal structure of 4.
Scheme 2
The 31P NMR spectrum of 5m displays a sharp singlet at d(P)
59.5 ppm accompanied by a single pair of selenium satellites
with a 31P–77Se coupling constant of 542 Hz. The 77Se NMR
spectrum shows a doublet at d(Se) −74.9 ppm with a matching
coupling constant. This shows that upon complexation there is
not only a change in chemical shift but also a significant decrease
in the 31P–77Se coupling constant, suggesting a small decrease in
P–Se bond order. The 1H and 13C NMR spectra show the same
pattern as the starting salt 1. The IR spectrum of 5m was virtually
unchanged by complexation and mass spectrometry found the
expected (M)+ at m/z 653.
Nickel(II) chloride was stirred at room temperature in
methanol with two equivalents of 1 to yield the complex NiL2
(L = [Ph(OMe)PSe2]−) 5m (Scheme 2). The complex was isolated
in high yield (74%) as a brown solid soluble in both chloroform
and dichloromethane.
◦
˚
Table 1 Selected bond lengths (A) and angles ( ) for 4
Na(1)–O(1)
Na(1)–O(10)
P(1)–O(1)
2.605(3)
2.383(3)
1.504(2)
2.1243(9)
Na(1)–O(7)
Na(1)–O(11)
P(1)–O(7)
2.396(2)
2.366(2)
1.617(2)
1.809(3)
P(1)–Se(1)
P(1)–C(1)
The X-ray structure of 5m (Fig. 2, Table 2) shows that
the nickel atom resides on a crystallographic inversion centre
and is coordinated by four selenium atoms in a square-planar
O(1)–Na(1)–O(7)
57.85(7)
O(1)–P(1)–O(7)
101.94(12)
◦
˚
Table 2 Selected bond lengths (A) and angles ( ) for 5m, 6m, 8m and 8e
5m
6m
8m
8e
M(1)–Se(1)
M(1)–Se(2)
M(1)–Se(2A)
M(1)–Se(11)
M(1)–Se(12)
M(1)–Se(22)
P(1)–Se(1)
2.3469(6)
2.3547(7)
2.3547(7)
—
—
—
2.1599(14)
2.1679(15)
—
—
1.586(4)
—
2.657(2)
2.731(2)
—
2.8296(6)
3.2689(5)
3.1327(5)
2.8757(5)
3.0651(5)
—
2.1649(9)
2.1589(9)
2.1745(9)
2.1480(9)
1.602(2)
1.603(2)
1.805(3)
1.809(3)
2.9249(12)
2.9335(9)
—
2.8522(9)
3.2235(10)
—
2.166(2)
2.160(2)
2.176(2)
2.151(2)
1.593(5)
1.591(6)
1.805(7)
1.793(9)
—
2.636(2)
2.634(2)
2.196(5)
2.180(6)
2.174(5)
2.167(5)
1.590(14)
1.597(15)
1.838(19)
1.784(19)
P(1)–Se(2)
P(11)–Se(11)
P(11)–Se(12)
P(1)–O(1)
P(11)–O(11)
P(1)–C(1)
1.812(5)
—
P(11)–C(11)
Se(1)–M(1)–Se(2)
Se(1)–P(1)–Se(2)
Se(11)–M(1)–Se(12)
Se(12)–P(11)–Se(11)
M(1)–Se(2)–M(1A)
Se(2)–M(1)–Se(2A)
89.87(2)
100.23(6)
—
—
—
—
82.94(7)
109.3(2)
—
114.0(2)
—
72.178(12)
113.20(4)
74.772(4)
113.28(4)
91.56(3)
75.22(3)
111.50(9)
71.63(3)
111.08(10)
—
—
84.488(16)
—
D a l t o n T r a n s . , 2 0 0 5 , 2 1 8 8 – 2 1 9 4
2 1 8 9

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phosphonodiselenoate salts” 1–3. The above NMR data would
suggest that, as with similar sulfur containing compounds, a
simple dimer is not the only species present in solution and that
a more complicated situation exists. Authors of studies con-
ducted on similar phosphorodithioate and phosphinodithioate
complexes of group 12 metals postulated that an equilibrium
exists with rapid exchange between a monomeric and a dimeric
species.36 A similar situation for the cadmium phosphonodise-
lenoate complexes would satisfy the observed spectral data.
IR spectra showed bands within the expected ranges, how-
ever in the mass spectra, the expected (M)+ ions were not
found. The most prominent fragments were the loss of one
phosphonodiselenoate ligand, [(Ph){OR}PSe2], and (1/2M)+.
The X-ray structure of 6m was determined (Fig. 3, Table 2)
and confirmed the proposed dimeric nature of the complex
in the solid state, with the structure being closely related to
the similar sulfur containing complexes.5–7 6m consists of an
eight-membered Cd2P2Se4 ring with two terminal bidentate
ligands each bound to one cadmium atom via both selenium
atoms and the other two acting as bridging ligands with their
selenium atoms binding to two different cadmium atoms. Similar
reactions were attempted with Hg(II) and Zn(II) and salts 1–3,
these proved to be unsuccessful resulting in the formation of
white insoluble solids.
Fig. 2 The X-ray crystal structure of 5m.
geometry with symmetric NiSe2P rings. The phenyl groups
of the two ligands are arranged in a trans arrangement, i.e.
above and below the metal coordination plane. This trans
arrangement is adopted in almost all known examples of
group 10 phosphonodithioate complexes1–7 with the exception of
bis[(methoxy)ferrocenylphosphonodithioato]nickel5 which was
shown to adopt the cis conformation. Two examples of group
10 phosphodiselenoate complexes have been structurally char-
acterised, Ni[Ph2PSe2]2 and Ni[(EtO)2PSe2]2,33 both exhibiting
33
a very similar structural motif to 5m. Similar reactions were
attempted with Ni(II) and salts 2 and 3, salts 1–3 were also stirred
with Pt(II) and Pd(II) salts however in all cases these proved
unsuccessful with the immediate formation of black amorphous
solids.
Cadmium(II) acetate was stirred at 50 ◦C with two equiv-
alents of phosphonodiselenoate sodium salts 1–3 to yield the
complexes of the type Cd2L4 (L = [Ph(OR)PSe2]−) 6, (Scheme 3).
Fig. 3 The X-ray crystal structure of 6m.
Similar reactions were carried out with two of the group
14 metals. In the cases of the reactions of Sn(II) with salts 2
and 3, no reaction occurred at room temperature and upon
heating decomposition to black amorphous solids occurred. In
all other cases reaction was carried out at 50 ◦C (Scheme 4)
yielding either white or yellow powders in high yield. As was
the case with 5m and 6 these compounds were found to be
soluble in both chloroform and dichloromethane. The 31P NMR
spectra of 7m and 8 display sharp singlets in the range d(P)
63.7–72.1 ppm accompanied by selenium satellites with 31P–77Se
coupling constants in the range of 578–592 Hz. The 77Se NMR
spectra show doublets in the range d(Se) 88.4–126.5 ppm.
Scheme 3
Although there are no literature examples of structurally char-
acterised cadmium complexes with such selenium containing
ligands, there have been many examples of cadmium complexes
of similar, sulfur-containing, phosphodithioate ligands. In all
cases these exhibit a structural motif consisting of an eight-
membered Cd2P2S4 ring with two terminal bidentate ligands
each bound to one cadmium atom via both sulfurs and the other
two acting as bridging ligands with their sulfur atoms binding
to two different cadmium atoms.34,35
The cadmium complexes 6 were isolated in high yields as
white solids soluble in chloroform and dichloromethane. The
31P NMR spectra of 6 display sharp singlets in the range d(P)
64.8–74.3 ppm with 31P–77Se coupling constants in the range of
554–561 Hz. The 77Se NMR spectra show doublets in the range
Scheme 4
In the mass spectra the expected (M)+ ion was observed only in
the case of 8e, for all others the most prominent fragments were
the loss of one phosphonodiselenoate ligand, [(Ph){OR}PSe2],
and (1/2M)+. This result would suggest that compounds 7m
1
d(Se) 223.5–260.0 ppm whilst the H and 13C spectra of these
complexes show the same pattern as their corresponding “free
2 1 9 0
D a l t o n T r a n s . , 2 0 0 5 , 2 1 8 8 – 2 1 9 4

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and 8 all exhibit similar covalently bound dimeric structures but,
as was the case for similar sulfur complexes,5–7 this hypothesis
has been found to be incorrect. X-Ray studies conducted on
8m and 8e show different structural motifs indicating that for
compounds 7m and 8 a more complicated situation than that
proposed for the cadmium complexes may exist.
There have been no structurally characterised examples of
tin or lead phosphodiselenoate complexes of this type. Only
one example of a tin phosphodithioate complex has been
studied crystallographically, [Sn{(OPh)2PS2}2]2,34 exhibiting a
dimeric structure similar to that of known phosphodithioate
complexes of group 12 metals and 6m. Several examples of
lead phosphodithioate complexes are known exhibiting a range
of structural motifs34,35 including distinct dimeric pairs, infinite
chain polymers held together by long-range secondary Pb · · · S
interactions and a covalently bonded infinite chain polymer.
The X-ray structure of 8e (Fig. 4, Table 2) exhibits a similar
structure to those adopted by bis[(isopropoxy)-4-methoxy-
phenylphosphonodithioato]lead6 and bis[(ethoxy)ferrocenyl-
phosphonodithioato] lead.7 The lead centre adopts a distorted
trigonal-bipyramidal geometry with a vacant site which provides
for the weak Pb · · · Se interactions. The inter-unit secondary
˚
Pb · · · Se distance (3.39(1) A) is significantly longer than the
˚
intra-unit Pb · · · Se distances (Pb(1)–Se(1) 2.9249(12) A, Pb(1)–
˚
Se(2) 2.93335(9) A), leading to the formation of an eight-
membered quasicyclic species.
Fig. 5 The X-ray crystal structure of 8m. Upper diagram, dimeric
structure; lower diagram, crystal packing within the molecule.
to one Pb atom only). The other ligand is bound to both lead
atoms leading to the formation of the central Pb2Se2 ring. The
structure is closely related to 8e, the difference being that the
Pb · · · Se secondary interactions holding the dimeric structure
of 8e together are significantly shorter covalent bonds in 8m.
The dimeric units in 8m are weakly linked together in a network
of Pb · · · Se and Se · · · Se interactions in the solid state. This
structure can also be seen to be related to 6m by a simple
translation of Se(2) and Se(2A), (Fig. 6).
Fig. 4 The X-ray crystal structure of 8e. Upper diagram, single
monomeric unit with a “vacant” site at Pb; lower diagram, pair of units
forming dimeric structure. C(15) and C(16) are disordered and the figure
only shows one orientation [C(15a) and C(16a)].
The X-ray structure of 8m (Fig. 5, Table 2) reveals a somewhat
different structural motif. The structure is built around a
central four-membered Pb2Se2 ring. Both lead atoms in the
structure adopt more obvious trigonal-bipyramid geometry
and are bound to two different types of ligand. One of the
ligands is terminal, bidentate chelating (both Se atoms bound
Fig. 6 The interconversion pathway between the structural motifs
displayed by 8m and 6m.
We have shown that the reaction of WR with NaOR (R = Me,
Et and iPr) in the corresponding alcohol gives the non-symmetric
phosphonodiselenoate anions [Ph(RO)PSe2]− as their sodium
D a l t o n T r a n s . , 2 0 0 5 , 2 1 8 8 – 2 1 9 4
2 1 9 1

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salts. The structure of a product of the hydrolysis of one of these
salts gave an interesting cubane-like structure. In an analogous
manner to the similar sulfur containing anions5–7 these sodium
salts have been shown to form some stable complexes with a
range of metals (Ni, Cd, Pb and Sn). The nickel complex ob-
tained was shown to adopt a similar structure to those displayed
for the sulfur complexes discussed, the complex displaying a
square-planar ML2 motif with the phenyl groups adopting
a ‘trans’ configuration i.e. above and below the coordination
plane. The structure of a cadmium complex was obtained and
was again shown to be analogous to those displayed by phos-
phodithioate cadmium compounds, adopting a dimeric M2L4
structure containing an eight-membered Cd2P2Se4 ring.
Two distinctly different lead complexes are reported, one
consisting of dimeric pairs similar to those displayed for the dis-
cussed lead phosphonodithioate structures but in this case there
are no obvious Pb · · · Ar interactions and the dimeric structure is
held together solely by long-range Pb · · · Se interactions between
the monomeric units. The other structure adopts a completely
different structural motif, the complex displays a novel dimeric
ML4 structure built around a central four-membered P2Se2
ring. This work clearly demonstrates the versatile coordination
behaviour of the [Ph(OR)PSe2]− ligand.
through a small Celite pad. The filtrate was concentrated under
vacuum to ca. 5 cm3 and hexane (30 cm3) was added to
precipitate the product as a pale yellow solid (1.308 g, 83%).
Found (Calc. for C8H10NaOPSe2): C 30.11 (28.76), H 3.67
(3.02)%. 31P NMR (CD3OH) d: 78.8 (s, 1J(31P–77Se) 669.0 Hz). 1H
NMR (CD3OD) d: 8.21–8.11 (m, 2H, Ph), 7.40–7.36 (m, 3H, Ph),
4.04 (dq = quartet of doublets, 2H, 3J(31P–1H) 2.0 Hz, 3J(1H–1H)
3
7.1 Hz, CH2), 1.27 (t, 3H, J(1H–1H) 7.1 Hz, CH3). 13C NMR
1
(CD3OD) d: 143.9 (d, J(31P–13C) 86.2 Hz, Ph C-1), 130.1 (d,
4J(31P–13C) 3.1 Hz, p-Ph), 129.6 (d, 3J(31P–13C) 12.5 Hz, m-Ph),
127.2 (d, 2J(31P–13C) 13.5 Hz, o-Ph), 61.2 (d, 2J(31P–13C) 6.2 Hz,
CH2), 15.5 (d, 3J(31P–13C) 9.3 Hz, CH3). 77Se NMR (CD3OD) d:
71.1 (d, 1J(31P–77Se) 669.6 Hz). Selected IR data (KBr) m/cm−1:
1178 (m), 1015 (s), 542 (s), 497 (s). Mass spectrum (ES−): m/z
313 (M − Na)−.
(Isopropoxy)phenylphosphonodiselenoate sodium salt (3).
Small pieces of sodium ◦(0.067 g, 2.91 mmol) were stirred in
propan-2-ol (20 cm3) at 0 C until fully dissolved. To this solution
Woollins reagent (0.775 g, 1.46 mmol) was added and heated at
60 ◦C for 1 h. The reaction mixture was allowed to cool to room
temperature and the resulting pink solution was filtered through
a small Celite pad. The filtrate was concentrated under vacuum
to ca. 5 cm3 and hexane (30 cm3) was added to precipitate
the product as a white solid (0.854 g, 84%). Found (Calc. for
C9H12NaOPSe2): C 31.69 (31.06), H 3.71 (3.47)%. 31P NMR
(CD3OD) d: 75.5 (s, 1J(31P–77Se) 666.7 Hz). 1H NMR (CD3OD)
d: 8.16–8.09 (m, 2H, Ph), 7.36–7.26 (m, 3H, Ph), 4.83 (dsept =
Experimental
General
3
3
septet of doublets, 1H, J(31P–1H) 2.0 Hz, J(1H–1H) 6.1 Hz,
Unless otherwise stated, operations were carried out under an
oxygen-free nitrogen atmosphere using predried solvents and
standard Schlenk techniques. All reagents were purchased from
Aldrich, Acros or Lancaster and used as received. Infrared
spectra were recorded as KBr discs in the range 4000–350 cm−1
on a Perkin-Elmer System 2000 Fourier-transform spectrometer,
1H, 31P, 13C and 77Se NMR spectra were recorded using a
Jeol GSX Delta 270 FT NMR spectrometer. Microanalyses
were performed by the University of St. Andrews microanalysis
service. Mass spectra were recorded by both the University of St.
Andrews mass spectrometry service and the EPSRC National
Mass Spectrometry Service Centre at Swansea University. We
are grateful to Johnson Matthey PLC for the loan of precious
metals.
CH), 1.24 (d, 3H, 3J(1H–1H) 6.2 Hz, CH3) 1.13 (d, 3H, 3J(1H–
1H) 6.2 Hz, CH3). 13C NMR (CD3OD) d: 144.9 (d, J(31P–13C)
1
87.2 Hz, Ph C-1), 129.7 (d, 3J(31P–13C) 11.4 Hz, m-Ph), 129.5 (d,
4J(31P–13C) 3.1 Hz, p-Ph), 126.8 (d, J(31P–13C) 13.5 Hz, o-Ph),
2
70.0 (d, J(31P–13C) 6.2 Hz, CH), 23.4 (d, J(31P–13C) 4.2 Hz,
2
3
CH3). 77Se NMR (CD3OD) d: 87.4 (d, J(31P–77Se) 667.6 Hz).
1
Selected IR data (KBr) m/cm−1: 1179 (m), 1027 (s), 518 (m), 499
(s). Mass spectrum (ES−): m/z 325 (M − Na)−.
Bis[(methoxy)phenylphosphonodiselenooato]nickel (5m).
A
mixture of NiCl2 (0.020 g, 0.16 mmol) and 1 (0.100 g, 0.31 mmol)
in methanol (10 cm3) was stirred at room temperature for
18 h resulting in an obvious brown precipitate. The product
was collected by suction filtration, washed with methanol (2 ×
7 cm3) and dried in vacuo to give a brown solid (0.75 g, 74%).
Brown crystals suitable for X-ray analysis were grown by vapour
diffusion of hexane into a dichloromethane solution. Found
(Calc. for C14H16O2P2S4Ni): C 25.96 (25.76), H 2.00 (2.47)%.
Synthesis
(Methoxy)phenylphosphonodiselenoate sodium salt (1).
Small pieces of sodium (0.118 g, 5.13 mmol) were stirred in
methanol (20 cm3) at 0 ◦C until fully dissolved. To this solution
Woollins reagent (1.37 g, 2.57 mmol) was added and heated at
60 ◦C for 45 min. The reaction mixture was allowed to cool to
room temperature and the resulting green solution was filtered
through a small Celite pad. The filtrate was concentrated
under vacuum to ca. 5 cm3 and hexane (30 cm3) was added to
precipitate the product as a white solid (1.495 g, 91%). Found
1
1
31P NMR (CDCl3) d: 59.5 (s, J(31P–77Se) 542.3 Hz). H NMR
(CDCl3) d: 8.08–8.02 (m, 2H, Ph), 7.57–7.53 (m, 3H, Ph), 3.93
(d, 3H, 3J(31P–1H) 15.8 Hz, CH3). 13C NMR (CDCl3) d: 137.5 (d,
1J(31P–13C) 91.5 Hz, Ph C-1), 132.9 (d, 4J(31P–13C) 3.1 Hz, p-Ph),
129.4 (d, 3J(31P–13C) 12.5 Hz, m-Ph), 18.6 (d, 2J(31P–13C) 14.5 Hz,
o-Ph), 53.4 (d, 2J(31P–13C) 7.1 Hz, CH3). 77Se NMR (CDCl3) d:
−74.9 (d, 1J(31P–77Se) 542.4 Hz). Selected IR data (KBr) m/cm−1:
1180 (m), 1015 (s), 526 (m), 510 (s). Mass spectrum (EI+): m/z
653 (M − Na)+.
(Calc. for C7H8NaOPSe2): C 27.18 (26.27), H 3.04 (2.52)%. 31
P
1
1
NMR (CD3OD) d: 83.0 (s, J(31P–77Se) 675.1 Hz). H NMR
(CD3OD) d: 8.19–8.07 (m, 2H, Ph), 7.38–7.34 (m, 3H, Ph),
3.60 (d, 3H, J(31P–1H) 15.8 Hz, CH3). 13C NMR (CD3OD) d:
3
Bis[(methoxy)phenylphosphonodiselenoato]cadmium
(6m).
1
4
143.7 (d, J(31P–13C) 87.19 Hz, Ph C-1), 129.9 (d, J(31P–13C)
Cd(CH3COO)2·2H2O (0.167 g, 0.63 mmol) was added to a
solution of 1 (0.400 g, 1.25 mmol) in methanol (10 cm3) and
heated at 50 ◦C for 15 min resulting in an obvious white
precipitate. The product was collected by suction filtration,
washed with methanol (2 × 7 cm3) and dried in vacuo to give
a white solid (0.387 g, 88%). Colourless crystals suitable for
X-ray analysis were grown by vapour diffusion of hexane into a
dichloromethane solution. Found (Calc. for C28H32O4P4Se8Cd2):
C 23.54 (23.80), H 2.21 (2.28)%. 31P NMR (CDCl3) d: 74.3 (s,
1J(31P–77Se) 561.1 Hz). 1H NMR (CDCl3) d: 8.12–8.02 (m, 2H,
3.1 Hz, p-Ph), 129.6 (d, J(31P–13C) 12.5 Hz, m-Ph), 127.1 (d,
3
2J(31P–13C) 13.5 Hz, o-Ph), 51.0 (d, J(31P–13C) 6.2 Hz, CH3).
2
77Se NMR (CD3OD) d: 60.8 (d, 1J(31P–77Se) 674.0 Hz). Selected
IR data (KBr) m/cm−1: 1167 (m), 1020 (m), 532 (s), 502 (s).
Mass spectrum (ES−): m/z 299 (M − Na)−.
(Ethoxy)phenylphosphonodiselenoate sodium salt (2). Small
pieces of sodium (0.108 g, 4.70 mmol) were stirred in ethanol
(30 cm3) at 0 ◦C until fully dissolved. To this solution Woollins
reagent (1.25 g, 2.35 mmol) was added and heated at 60 ◦C
for 15 min. The reaction mixture was allowed to cool to
room temperature and the resulting yellow solution was filtered
3
Ph), 7.48–7.42 (m, 3H, Ph), 3.90 (d, 3H, J(31P–1H) 16.6 Hz,
1
CH3). 13C NMR (CDCl3) d: 137.1 (d, J(31P–13C) 91.3 Hz, Ph
4
3
C-1), 132.4 (d, J(31P–13C) 3.1 Hz, p-Ph), 130.1 (d, J(31P–13C)
2 1 9 2
D a l t o n T r a n s . , 2 0 0 5 , 2 1 8 8 – 2 1 9 4

View Article Online
1
13.5 Hz, m-Ph), 128.3 (d, 2J(31P–13C) 14.5 Hz, o-Ph), 53.9
(2.01)%. 31P NMR (CDCl3) d: 72.1 (s, J(31P–77Se) 593.9 Hz).
1H NMR (CDCl3) d: 8.04–7.95 (m, 2H, Ph), 7.49–7.43 (m, 3H,
Ph), 3.80 (d, 3H, 3J(31P–1H) 16.6 Hz, CH3). 13C NMR (CDCl3)
2
(d, J(31P–13C) 7.3 Hz, CH3). 77Se NMR (CDCl3) d: 223.5 (d,
1J(31P–77Se) 562.5 Hz). Selected IR data (KBr) m/cm−1: 1170
(m), 1023 (s), 531 (s), 504 (s). Mass spectrum (MALDI): m/z
710 (1/2M)+, 1118 (M − PSe2OC7H8)+.
d: 139.8 (d, J(31P–13C) 95.5 Hz, Ph C-1), 132.2 (d, J(31P–13C)
1
4
3.1 Hz, p-Ph), 129.6 (d, J(31P–13C) 12.5 Hz, m-Ph), 128.3 (d,
3
2J(31P–13C) 14.5 Hz, o-Ph), 53.2 (d, J(31P–13C) 6.2 Hz, CH3).
2
Bis[(ethoxy)phenylphosphonodiselenoato]cadmium (6e). Cd-
(CH3COO)2·2H2O (0.172 g, 0.65 mmol) was added to a solution
of 2 (0.431 g, 1.29 mmol) in ethanol (10 cm3) and heated at 50 ◦C
for 10 min resulting in an obvious white precipitate. The product
was collected by suction filtration, washed with methanol (2 ×
7 cm3) and dried in vacuo to give a white solid (0.344 g, 73%).
Found (Calc. for C32H40O4P4Se8Cd2): C 22.93 (23.17), H 2.06
77Se NMR (CDCl3) d: 95.6 (d, J(31P–77Se) 593.7 Hz). Selected
1
IR data (KBr) m/cm−1: 1168 (m), 1010 (s), 528 (m), 506 (s).
Mass spectrum (MALDI): m/z 1307 (M − PSe2OC7H9)+, 1605
(M)+.
Bis[(ethoxy)phenylphosphonodiselenoato]lead (8e). Pb(CH3-
COO)2·3H2O (0.245 g, 0.65 mmol) was added to a solution of 2
(0.431 g, 1.29 mmol) in ethanol (10 cm3) and heated at 50 ◦C for
10 min resulting in an obvious yellow precipitate. The product
was collected by suction filtration, washed with methanol (2 ×
7 cm3) and dried in vacuo to give a yellow solid (0.449 g, 84%).
Yellow crystals suitable for X-ray analysis were grown by vapour
diffusion of hexane into a chloroform solution. Found (Calc. for
C32H40O4P4Se8Pb2): C 22.82 (23.17), H 2.45 (2.43)%. 31P NMR
1
(2.43)%. 31P NMR (CDCl3) d: 69.3 (s, J(31P–77Se) 556.4 Hz).
1H NMR (CDCl3) d: 8.12–8.03 (m, 2H, Ph), 7.48–7.41 (m, 3H,
Ph), 4.04 (dq, 2H, 3J(31P–1H) 3.0 Hz, 3J(1H–1H) 7.1 Hz, CH2),
1.39 (t, 3H, 3J(1H–1H) 7.1 Hz, CH3). 13C NMR (CDCl3) d: 137.7
1
4
(d, J(31P–13C) 91.4 Hz, Ph C-1), 132.2 (d, J(31P–13C) 3.1 Hz,
p-Ph), 130.1 (d, 3J(31P–13C) 12.5 Hz, m-Ph), 128.3 (d, 2J(31P–13C)
14.5 Hz, o-Ph), 64.0 (d, 2J(31P–13C) 7.3 Hz, CH2), 16.0 (d, 3J(31P–
13C) 8.3 Hz, CH3). 77Se NMR (CDCl3) d: 237.6 (d, 1J(31P–77Se)
557.9 Hz). Selected IR data (KBr) m/cm−1: 1159 (m), 1017 (s),
536 (s), 500 (s). Mass spectrum (MALDI): m/z 734 (1/2M)+,
1158 (M − PSe2OC8H10)+.
(CDCl3) d: 67.7 (s, J(31P–77Se) 591.6 Hz). H NMR (CDCl3)
d: 8.05–7.95 (m, 2H, Ph), 7.47–7.39 (m, 3H, Ph), 4.04 (dq, 2H,
3J(31P–1H) 3.0 Hz, 3J(1H–1H) 7.1 Hz, CH2), 1.36 (t, 3H, 3J(1H–
1
1
1H) 7.1 Hz, CH3). 13C NMR (CDCl3) d: 140.2 (d, J(31P–13C)
1
94.5 Hz, Ph C-1), 132.1 (d, 4J(31P–13C) 3.1 Hz, p-Ph), 129.7 (d,
3J(31P–13C) 12.5 Hz, m-Ph), 128.4 (d, 2J(31P–13C) 14.5 Hz, o-Ph),
Bis[(isopropoxy)phenylphosphonodiselenoato]cadmium (6p).
A mixture of Cd(CH3COO)2·2H2O (0.217 g, 0.81 mmol) and 3
(0.570 g, 1.63 mmol) in propan-2-ol (10 cm3) was heated at 50 ◦C
for 1.5 h. The solvent was removed under reduced pressure,
the resulting pink solid was redissolved in dichloromethane
and filtered through a small Celite plug. The filtrate was
concentrated under vacuum to ca. 5 cm3 and hexane was added
to precipitate the product as a white solid (0.368 g, 59%).
Found (Calc. for C36H48O4P4Se8Cd2): C 28.66 (28.35), H 2.89
63.3 (d, J(31P–13C) 6.2 Hz, CH2), 16.2 (d, J(31P–13C) 9.3 Hz,
2
3
1
CH3). 77Se NMR (CDCl3) d: 109.9 (d, J(31P–77Se) 591.3 Hz).
Selected IR data (KBr) m/cm−1: 1175 (m), 1020 (s), 518 (m), 506
(s). Mass spectrum (MALDI): m/z 832 (1/2M)+, 1351 (M −
PSe2OC8H10)+.
Bis[(isopropoxy)phenylphosphonodiselenoato]lead (8p).
A
mixture of Pb(CH3COO)2·3H2O (0.217 g, 0.81 mmol) and 3
(0.570 g, 1.63 mmol) in propan-2-ol (10 cm3) was heated at 50 ◦C
for 1.5 h. The solvent was removed under reduced pressure,
the resulting pink solid was redissolved in dichloromethane
and filtered through a small Celite plug. The filtrate was
concentrated under vacuum to ca. 5 cm3 and hexane was added
to precipitate the product as a white solid (0.475 g, 68%).
Found (Calc. for C36H48O4P4Se8Pb2): C 25.13 (25.22), H 3.17
1
(3.17)%. 31P NMR (CDCl3) d: 64.8 (s, J(31P–77Se) 554.0 Hz).
1H NMR (CDCl3) d: 8.11–8.02 (m, 2H, Ph), 7.45–7.40 (m, 3H,
Ph), 5.21 (dsept, 1H, 3J(31P–1H) 2.7 Hz, 3J(1H–1H) 6.2 Hz,
CH), 1.41 (d, 6H, 3J(1H–1H) 6.2 Hz. 13C NMR (CDCl3) d:
1
4
138.5 (d, J(31P–13C) 92.4 Hz, Ph C-1), 132.0 (d, J(31P–13C)
3.1 Hz, p-Ph), 130.1 (d, J(31P–13C) 13.5 Hz, m-Ph), 128.2 (d,
3
2J(31P–13C) 14.5 Hz, o-Ph), 73.8 (d, J(31P–13C) 7.3 Hz, CH),
2
24.0 (d, J(31P–13C) 4.2 Hz, CH3). 77Se NMR (CDCl3) d: 260.0
3
1
(2.82)%. 31P NMR (CDCl3) d: 63.7 (s, J(31P–77Se) 586.9 Hz).
(d, 1J(31P–77Se) 554.3 Hz). Selected IR data (KBr) m/cm−1: 1177
(m), 1026 (m), 545 (s), 502 (s). Mass spectrum (MALDI): m/z
764 (1/2M)+, 1204 (M − PSe2OC9H12)+.
1H NMR (CDCl3) d: 8.04–7.95 (m, 2H, Ph), 7.47–7.38 (m, 3H,
Ph), 5.07 (dsept, 1H, 3J(31P–1H) 2.7 Hz, 3J(1H–1H) 6.2 Hz,
CH), 1.37 (d, 6H, 3J(1H–1H) 6.2 Hz. 13C NMR (CDCl3) d:
140.7 (d, J(31P–13C) 95.5 Hz, Ph C-1), 131.9 (d, J(31P–13C)
1
4
Bis[(methoxy)phenylphosphonodiselenoato]tin (7m). SnCl2
(0.167 g, 0.63 mmol) was added to a solution of 1 (0.400 g,
1.25 mmol) in methanol (10 cm3) and heated at 50 ◦C for 45 min
resulting in an obvious yellow precipitate. The product was
collected by suction filtration, washed with methanol (2 × 7 cm3)
and dried in vacuo to give a pale yellow solid (0.232 g, 52%).
Found (Calc. for C28H32O4P4Se8Sn2): C 23.41 (23.59), H 2.00
3.1 Hz, p-Ph), 129.6 (d, J(31P–13C) 12.5 Hz, m-Ph), 128.3 (d,
3
2J(31P–13C) 14.5 Hz, o-Ph), 73.0 (d, J(31P–13C) 7.3 Hz, CH),
2
24.4 (d, J(31P–13C) 4.2 Hz, CH3). 77Se NMR (CDCl3) d: 126.5
3
(d, 1J(31P–77Se) 588.8 Hz). Selected IR data (KBr) m/cm−1: 1177
(m), 1023 (m), 524 (s), 497 (m). Mass spectrum (MALDI): m/z
764 (1/2M)+, (M − PSe2OC9H12)+ 1204.
1
(2.26)%. 31P NMR (CDCl3) d: 67.5 (s, J(31P–77Se) 577.5 Hz).
1H NMR (CDCl3) d: 8.01–7.92 (m, 2H, Ph), 7.49–7.44 (m, 3H,
Ph), 3.84 (d, 3H, 3J(31P–1H) 16.6 Hz, CH3). 13C NMR (CDCl3)
X-Ray crystallography
Table 3 lists details of data collections and refinements. For 4,
data were collected at 93 K using Cu-Karadiation and a RAPID
Image plate, for 5m at 125 K using a Bruker SMART [sealed
tube] system, for 6m, data were collected at 93 K using Mo-Ka
radiation [MM007 Rotating Anode source with confocal optics,
Rigaku Saturn detector] for 8m and 8e, data were collected at
93 K using Mo-Ka radiation [MM007 Rotating Anode source
with confocal optics, Rigaku Mercury detector]. Intensities
were corrected for Lorentz-polarisation and for absorption. The
structures were solved by the heavy-atom method or by direct
methods. The positions of the hydrogen atoms were idealised.
Refinements were by full-matrix least squares based on F2 using
SHELXTL.37 For 6m only the Cd, Se and P atoms were refined
anisotropically. For 8e, C(15) and C(16) are disordered C(15a/b)
and C(16a/b) were refined isotropically and the protons on
C(15b) and C(16b) are not included in the refinement.
1
4
d: 138.1 (d, J(31P–13C) 98.6 Hz, Ph C-1), 132.3 (d, J(31P–13C)
3.1 Hz, p-Ph), 129.7 (d, J(31P–13C) 13.5 Hz, m-Ph), 128.4 (d,
3
2J(31P–13C) 14.5 Hz, o-Ph), 53.1 (d, J(31P–13C) 6.2 Hz, CH3).
2
77Se NMR (CDCl3) d: 88.4 (d, J(31P–77Se) 576.3 Hz). Selected
1
IR data (KBr) m/cm−1: 1169 (m), 1022 (s), 520 (s), 503 (m).
Mass spectrum (MALDI): m/z 1134 (M − PSe2OC7H8)+.
Bis[(methoxy)phenylphosphonodiselenoato]lead (8m). Pb-
(CH3COO)2·3H2O (0.237 g, 0.63 mmol) was added to a solution
of 1 (0.400 g, 1.25 mmol) in methanol (10 cm3) and heated at
50 ◦C for 10 min resulting in an obvious yellow precipitate.
The product was collected by suction filtration, washed with
methanol (2 × 7 cm3) and dried in vacuo to give a yellow solid
(0.456 g, 91%). Yellow crystals suitable for X-ray analysis were
grown by vapour diffusion of hexane into a chloroform solution.
Found (Calc. for C28H32O4P4Se8Pb2): C 21.37 (20.99), H 2.32
D a l t o n T r a n s . , 2 0 0 5 , 2 1 8 8 – 2 1 9 4
2 1 9 3

View Article Online
Table 3 Details of the X-ray data collections and refinements for 4, 5m, 6m, 8m and 8e
Compound
4
5m
6m
8m
8e
Empirical formula
M
C9H14NaO3PSe
303.12
Colourless, block
0.1 × 0.1 × 0.05
Monoclinic
C2/c
25.7072(6)
8.4911(2)
25.3606(5)
90
112.228(2)
90
C14H16NiO2P2Se4
652.76
Brown, plate
0.15 × 0.1 × 0.02
Triclinic
¯
P1
7.2868(17)
8.1246(19)
9.089(2)
70.312(4)
71.498(4)
85.256(4)
480.24(19)
1
C28H32Cd2O4P4Se8
1412.90
Colourless, prism
0.15 × 0.03 × 0.01
Orthorhombic
Pna21
24.5905(4)
6.9511(1)
48.2341(9)
90
90
90
8244.7(2)
8
2.277
C28H32Pb2O4P2Se4
1602.48
Yellow, block
0.1 × 0.05 × 0.05
Monoclinic
P21/n
17.309(4)
6.4914(10)
18.073(4)
90
92.072(5)
90
C16H20PbO2P2Se4
829.29
Yellow, block
0.1 × 0.1 × 0.1
Triclinic
¯
P1
6.4975(7)
13.1066(13)
14.502(2)
110.741(14)
97.96(2)
100.16(2)
1109.4(2)
2
Crystal colour, habit
Crystal dimensions/mm
Crystal system
Space group
˚
a/A
˚
b/A
˚
c/A
a/◦
b/◦
c /◦
3
˚
U/A
5124.4(7)
16
1.572
2029.3(7)
2
2.623
Z
Dc/g cm−3
2.257
8.759
2.482
14.318
l/mm−1
5.386
8.282
15.650
F(000)
2432
7507
4475 (0.0464)
0.0452, 0.1133
310
2122
1254 (0.0158)
0.0464, 0.1183
5280
13389
13389 (0.0000)
0.0618, 0.1669
1456
12314
3650(0.0190)
0.0176, 0.0387
760
6681
3780 (0.0588)
0.0400, 0.0957
Measured reflections
Independent reflections (Rint
Final R1, wR2 [I > 2r(I)]
)
CCDC reference numbers 266255–266259.
See http://www.rsc.org/suppdata/dt/b5/b503793j/ for cry-
stallographic data in CIF or other electronic format.
17 I. P. Parkin, M. J. Pilkington, A. M. Z. Slawin and D. J. Williams,
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18 I. Baxter, A. F. Hill, J. M. Malget, A. J. P. White and D. J. Williams,
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19 W. Kuchen and B. Knop, Angew. Chem., Int. Ed., 1964, 3, 507.
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C. V. Francis, A. P. S. Jurd, M. G. Martinelli, A. J. P. White and D. J.
Williams, Inorg. Chem., 2004, 43, 4802.
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2 1 9 4
D a l t o n T r a n s . , 2 0 0 5 , 2 1 8 8 – 2 1 9 4