Complexes of WOCl4 and WSCl4 with neutral N- and O-donor ligands: Synthesis, spectroscopy and structures

Article abstract of DOI:10.1016/j.poly.2019.01.044

The complexes [WOCl₄(L)] and [WSCl₄(L)] (L = OPPh₃, OPMe₃, pyridine, 2,2′-bipyridyl), [{WOCl₄}₂(μ-L-L)] and [{WSCl₄}₂(μ-L-L)] (L-L = Ph₂P(O)(CH₂)_nP(O)Ph₂ (n = 1, 2)) have been prepared from WOCl₄ or WSCl₄ and the ligands in anhydrous CH₂Cl₂ solution, and characterised by microanalysis, IR and NMR (¹H, ³¹P{¹H}) spectroscopy. X-Ray crystal structures are reported for [WOCl₄(OPPh₃)], [{WOCl₄}₂(μ-Ph₂P(O)(CH₂)P(O)Ph₂)] and [{WSCl₄}₂(μ-Ph₂P(O)(CH₂)₂P(O)Ph₂)]. All, except those of 2,2′-bipyridyl, are six-coordinate with the neutral donor trans to W[dbnd]O or W[dbnd]S. Spectroscopic data suggest that the [WOCl₄(2,2′-bipy)] and [WSCl₄(2,2′-bipy)] are seven-coordinate. Comparison of the structural and spectroscopic data for the two series of complexes indicate little difference in Lewis acidity between the two tungsten(VI) moieties. Decomposition of [WOCl₄(OPMe₃)] in solution gave the cyclic trimer [W₃O₃(μ-O)₃Cl₆(OPMe₃)₃], the structure of which revealed a six-membered W₃O₃ ring core with very asymmetric oxido-bridges. The structure of the tungsten(V) complex [WOCl₃(2,2′-bipy)] is also reported.

Full text of DOI:10.1016/j.poly.2019.01.044

Accepted Manuscript
Complexes of WOCl4 and WSCl4 with neutral N- and O- donor ligands: syn-
thesis, spectroscopy and structures
Victoria K. Greenacre, Andrew L. Hector, William Levason, Gillian Reid,
Danielle E. Smith, Laura Sutcliffe
PII:
S0277-5387(19)30059-2
https://doi.org/10.1016/j.poly.2019.01.044
POLY 13717
DOI:
Reference:
Polyhedron
To appear in:
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Revised Date:
Accepted Date:
19 December 2018
16 January 2019
17 January 2019
Please cite this article as: V.K. Greenacre, A.L. Hector, W. Levason, G. Reid, D.E. Smith, L. Sutcliffe, Complexes
of WOCl4 and WSCl4 with neutral N- and O- donor ligands: synthesis, spectroscopy and structures, Polyhedron
(2019), doi: https://doi.org/10.1016/j.poly.2019.01.044
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Complexes of WOCl4 and WSCl4 with neutral N- and O- donor ligands:
synthesis, spectroscopy and structures.
Victoria K. Greenacre, Andrew L. Hector, William Levason,* Gillian Reid, Danielle E.
Smith, and Laura Sutcliffe
School of Chemistry, University of Southampton, Southampton SO17 1BJ, UK
Keywords: tungsten oxide tetrachloride : tungsten sulfide tetrachloride: phosphine oxide :
2,2’-bipyridyl : X-ray structures
Abstract
The complexes [WOCl4(L)] and [WSCl4(L)] (L = OPPh3, OPMe3, pyridine, 2,2’-bipyridyl),
[{WOCl4}2(µ-L-L)] and [{WSCl4}2(µ-L-L)] (L-L = Ph2P(O)(CH2)nP(O)Ph2 (n = 1, 2)) have
been prepared from WOCl4 or WSCl4 and the ligands in anhydrous CH2Cl2 solution, and
characterised by microanalysis, IR and NMR (1H, 31P{1H}) spectroscopy. X-Ray crystal
structures are reported for [WOCl4(OPPh3)], [{WOCl4}2(µ-Ph2P(O)(CH2)P(O)Ph2)] and
[{WSCl4}2(µ-Ph2P(O)(CH2)2P(O)Ph2)]. All, except those of 2,2’-bipyridyl, are six-coordinate
with the neutral donor trans to W=O or W=S. Spectroscopic data suggest that the [WOCl4(2,2’-
bipy)] and [WSCl4(2,2’-bipy)] are seven-coordinate. Comparison of the structural and
spectroscopic data for the two series of complexes indicate little difference in Lewis acidity
between the two tungsten(VI) moieties. Decomposition of [WOCl4(OPMe3)] in solution gave
the cyclic trimer [W3O3(µ-O)3Cl6(OPMe3)3], the structure of which revealed a six-membered
W3O3 ring core with very asymmetric oxido-bridges. The structure of the tungsten(V) complex
[WOCl3(2,2’-bipy)] is also reported.
1. Introduction
The oxide and sulfide halides of the early d-block metals in their higher oxidation states are
Lewis acidic and form complexes with a variety of neutral ligands [1]. In the solid state
tungsten oxide tetrachloride contains square pyramidal WOCl4 units linked into chains via
asymmetric W=O…W bridges (WO = 1.8, 2.2 Å) [2] whilst in WSCl4 the square pyramidal
 Corresponding author . email wxl@soton.ac.uk
1

core units are weakly chloride-bridged to form dimers [SCl3W(µ-Cl)2WCl3S] [3]. A second
polymorph of WSCl4 is a tetramer [Cl4SW(µ-Cl)SCl2W(µ-Cl)2WCl2S(µ-Cl)WSCl4] in which
the dimer core is linked by single chlorine bridges to two other WSCl4 units [4]. Neutral ligand
complexes of WOCl4, were first reported some years ago, obtained by direct reaction of the
ligand with WOCl4, by abstraction of oxygen from O-donor ligands, and for some examples
by hydrolysis of WCl6 complexes [1,5,6]. Typical examples include [WOCl4(RCN)] (R =Me,
Et, Ph) [7,8], [WOCl4(thf)] [7,9], [{WOCl4}2(1,4-dioxane)] [7,9], [WOCl4(OMe2)] [10],
[WOCl4(Me4urea)] [11], [WOCl4{o-C6H4(AsMe2)2}] [12], [WOCl4(PR3)] (R3 = Ph3, Ph2Et),
[WOCl4(PR3)2] (R3 = Ph3, Et3) and [WOCl4(OPPh3)n] (n = 1 or 2) [13]. Other workers have
reported that phosphines abstract oxygen from WOCl4 to form phosphine oxide complexes of
W(IV) [14]. Detailed investigation of the reactions of WCl6 with ethers, polyethers, ketones
and amides have shown that while [WOCl4(ligand)] are formed in some cases, the chemistry
depends upon the particular ligand and the reaction conditions, and other products include
complexes of fragmented ligands and tungsten(V) complexes containing WCl5 or WOCl3
[10,11,15,16]. A few complexes of WOBr4 have been described [1,5,6,7], along with the fluoro
complexes, [WOF4(L)] (L = MeCN, OPPh3, thf, dmso, py, PMe3) and [WOF4(diphosphine)]
(diphosphine = o-C6H4(PMe2)2 or Me2PCH2CH2PMe2) that were reported very recently
[17,18].
Some corresponding tungsten(VI) sulfide tetrachloride complexes, including [WSCl4(L)] (L
= thf, py, RCN), [{WSCl4}2(µ-1,4-dioxane)] and [(WSCl4)2(µ-MeS(CH2)2SMe)] have been
prepared, but appear to be less stable than those of WOCl4 [1,5,19,20]. Possible applications
of complexes of metal sulfide halides include their use as reagents for the chemical vapour
deposition of the layered metal dichalcogenide thin film materials [21,22]. We report here a
comparison of the complexes of WOCl4 and WSCl4 with a series of neutral N- and O-donor
ligands.
2. Results and Discussion
2.1 Phosphine oxide complexes.
The WOCl4 and WSCl4 precursors were made by minor modifications of the literature route
from WCl6 and O(SiMe3)2 or S(SiMe3)2, respectively, in CH2Cl2 [23]. The complexes were
subsequently synthesised by reaction of the appropriate ligand with the WECl4 (E = O or S) in
anhydrous CH2Cl2 Attempts to prepare the complexes by “one pot” reactions, i.e. by adding
the O(SiMe3)2 or S(SiMe3)2 to WCl6 in CH2Cl2, followed by addition of the ligand, were less
2

successful and often gave impure products or mixtures. The complexes are very readily
hydrolysed with formation of the robust [WO2Cl2(L)n] (and other products) and use of
anhydrous ligands and solvents with Schlenk and glove box techniques is essential to obtain
pure complexes. In several cases, adventitious hydrolysis led to the isolation of [WO2Cl2(L)n]
complexes, as seen in other WOX4/WO2X2 systems [1,17]. The reaction of WOCl4 with one
molar equivalent of OPPh3 or OPMe3 or 0.5 molar equivalents of Ph2P(O)(CH2)nP(O)Ph2 (n =
1, dppmO2; n = 2, dppeO2) in anhydrous CH2Cl2 solution gave orange or yellow complexes
[WOCl4(OPR3)] (R = Me, Ph) or [{WOCl4}2(L-L)] (L-L = dppmO2, dppeO2) Scheme 1.
E
Cl
Cl
Cl
Cl
W
O
P
R
R
R
OPR3
R = Me, Ph
E
E
E
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
2,2'-bipy
Pyridine
W
N
Cl
Cl
Cl
Cl
W
W
N
N
(CH2)n(Ph2PO)2
n = 1, 2
E
Cl
Cl
Cl
Cl
W
O
P
Ph
P
Ph
Ph
(CH2)n
O
W
E
Ph
Cl
Cl
Cl
Cl
E = O or S
Scheme 1. Synthesis of the complexes of WECl4
X-Ray crystal structures were determined for [WOCl4(OPPh3)] and [{WOCl4}2(dppmO2)],
with crystals grown from CH2Cl2 solution by slow evaporation. They show distorted octahedral
tungsten centres (Figures 1 and 2). Although they are not isomorphous, the structure of
[WOCl4(OPPh3)] is very similar to that of [WOF4(OPPh3)] [17] with the OPPh3 trans to W=O
and the tungsten above the WCl4 plane towards the oxido group, as usually found in complexes
of this type. The d(W=O) are not significantly different, 1.6841(16) Å in the present complex
3

and 1.682(5) Å in the fluoride, although the W-OP is shorter in the present complex. 2.1041(14)
Å compared to 2.141(4) Å in the fluoride.
Figure 1 The structure of [WOCl4(OPPh3)] showing the atom numbering scheme. H atoms are omitted
for clarity. Selected bond lengths (Å) and angles (°) are: W1–Cl1 = 2.3457(5), W1–Cl2 = 2.3012(6),
W1–Cl3 = 2.2935(6), W1–Cl4 = 2.3148(6), W1–O1 = 1.6841(16), W1–O2 = 2.1041(14), Cl2–W1–Cl1
= 87.76(2), Cl3–W1–Cl2 = 92.66(2), Cl3–W1–Cl4 = 90.98(2), Cl4–W1–Cl1 = 86.61(2), O1–W1–Cl1
= 94.95(6), O1–W1–Cl2 = 94.68(7), O1–W1–Cl3 = 95.15(6), O1–W1–Cl4 = 96.60(7), O1–W1–O2 =
178.33(8), O2–W1–Cl1 = 84.62(4), O2–W1–Cl2 = 83.69(4), O2–W1–Cl3 = 85.32(4), O2–W1–Cl4 =
85.00(4). The second molecule in the asymmetric unit is very similar.
In the dimeric [{WOCl4}2(dppmO2)] (Figure 2) the tungsten environments and the W=O and
WCl bond lengths are similar to those in the OPPh3 complex, while the W–OP are slightly
longer, and also surprisingly disparate (W1–O2 = 2.1886(12), W2–O3 = 2.1224(13) Å).
The spectroscopic properties of the four complexes are unexceptional. The IR spectra exhibit
a single strong ν(W=O) in the range 957985 cm1, broad ν(WCl) ~ 337 +/ 5 cm1 and with
the ν(P=O) reduced by > 60 cm1 from the values in the parent ligands. The IR spectrum of
[WOCl4(OPPh3)] has been reported twice, but with poor agreement [13,24]; our data are in
agreement with the report of Behzadi et. al. [24]. The 31P{1H} NMR spectra show substantial
high frequency shifts for the phosphoryl group upon coordination and for the complexes of
[WOCl4(OPR3)] are very similar to those observed for the corresponding [WOF4(OPR3)] [17];
(the [{WOF4}2(diphosphine dioxide)] complexes have not been reported). The report [13] that
[WOCl4(OPPh3)] exhibits a low frequency coordination shift of –4 ppm is clearly in error.
4

Figure 2 The structure of [{WOCl4}2(dppmO2)] showing the atom numbering scheme. H atoms are
omitted for clarity. Selected bond lengths (Å) and angles (°) are: W1–Cl1 = 2.3010(5), W1–Cl4 =
2.3092(5), W1–Cl3 = 2.3190(5), W1–Cl2 = 2.3142(5), W1–O2 = 2.1886(12), W1–O1 = 1.6861(14),
W2–Cl6 = 2.3119(5), W2–Cl8 = 2.3175(5), W2–Cl5 = 2.3143(5), W2–Cl7 = 2.3198(5), W2–O3 =
2.1224(13), W2–O4 = 1.6846(14), Cl–W–Cl(cis) 88.129(18)–90.672(19), OP–W–Cl = 83.60(4)–
87.35(4), O–W–Cl = 93.36(5)–96.94(6), O1–W1–O2 = 176.96(6), O4–W2–O3 = 179.31(7).
The reaction of WSCl4 with OPPh3, OPMe3, dppmO2 and dppeO2 in anhydrous CH2Cl2
solution, produced brown powders, [WSCl4(OPR3)] (R = Me, Ph) and [{WOCl4}2(L-L)] (L-L
= dppmO2, dppeO2). The X-ray crystal structure of [{WSCl4}2(dppeO2)] (Figure 3) shows a
centrosymmetric dimer with the tungsten lying out of the WCl4 plane towards the sulfide group.
The W–OP = 2.159(2) Å, is similar to the average of the corresponding links in
[{WOCl4}2(dppmO2)] (2.155 (6) Å).
5

Figure 3 The structure of [{WSCl4}2(dppeO2)] showing the atom numbering scheme. H atoms are
omitted for clarity. Selected bond lengths (Å) and angles (°) are: W1–Cl3 = 2.3126(8), W1–Cl4 =
2.3166(8), W1–Cl2 = 2.3484(8), W1–Cl1 = 2.3423(7), W1–S1 = 2.1059(9), W1–O1 = 2.159(2), Cl3–
W1–Cl4 = 90.29(3), Cl3–W1–Cl2 = 89.06(3), Cl4–W1–Cl1 = 89.47(3), Cl1–W1–Cl2 = 87.80(3), S1–
W1–Cl3 = 97.99(3), S1–W1–Cl4 = 95.99(3), S1–W1–Cl2 = 97.18(3), S1–W1–Cl1 = 96.79(3), S1–W1–
O1 = 179.02(6), O1–W1–Cl3 = 82.33(6), O1–W1–Cl4 = 83.08(6), O1–W1–Cl2 = 83.74(6),O1–W1–
Cl1 = 82.91(6).
2.2 Complexes of N-heterocycles
To compare the complexes of the O-donor phosphine oxides with those of N-donor ligands,
the complexes with pyridine and 2,2’-bipyridyl were examined. The yellow [WOCl4(py)] and
brown [WSCl4(py)] complexes [7,19] were made by reacting the constituents in a 1:1 molar
ratio in dry CH2Cl2 solution. The products are diamagnetic and the spectroscopic properties are
unexceptional. Under reflux or with longer reaction times, reduction to W(V) species occurs
[19]. The reaction of WOCl4 with 2,2’-bipyridyl has been reported before [7,25], the green
solid being variously formulated as [WOCl4(2,2’-bipy)] or the paramagnetic W(V) complex,
[WOCl3(2,2’-bipy)]. By conducting the reaction in CH2Cl2 solution at room temperature and
with a relatively short reaction time, we obtained a green complex [WOCl4(2,2’-bipy)], which
6

was diamagnetic and with the 1H NMR spectrum showing equivalent pyridyl rings. Repeated
attempts to obtain crystals for an X-ray study have been unsuccessful, but it is highly likely
that the complex [WOCl4(2,2’-bipy)], contains seven-coordinate tungsten, probably
pentagonal bipyramidal with axial O/Cl. Similar seven-coordination is established in
[WOCl4{o-C6H4(AsMe2)2}] [12] and in several complexes of WOF4 [17,18,26]. The ν(W=O)
of 970 cm1 is lower than the values observed in the six-coordinate complexes, but similar to
those in [WOCl4{o-C6H4(AsMe2)2}] (964 cm1) [12], [WOF4(2,2’-bipy)] (968 cm1) or
[WOF4(py)2] (973 cm1) [26], which supports the assignment of the higher coordination
number, and the proposed geometry in which the oxido-group can occupy an axial position.
The new complex [WSCl4(2,2’-bipy)] was obtained as a red solid, and is spectroscopically very
similar. Attempts to grow crystals of the seven-coordinate W(VI) complex from CH2Cl2
solution over several days resulted in crystals being obtained of the previously reported six-
coordinate [WSCl3(2,2’-bipy)] [19] (Figure 4).
Figure 4 The structure of [WSCl3(bipy)] showing the atom numbering scheme. Two
crystallographically independent molecules were present in the asymmetric unit, one is shown here for
clarity. H atoms are omitted for clarity. Selected bond lengths (Å) and angles (°) are: W1–Cl1 =
2.284(4), W1–Cl2 = 2.356(3), W1–Cl3 = 2.363(3), W1–S1 = 2.206(4), W1–N1 = 2.268(11), W1–N2 =
2.215(11), Cl2–W1–Cl3 = 166.21(11), S1–W1–Cl2 = 96.40(13), S1–W1–N1 = 166.1(3), S1–W1–N2
= 93.3(3), S1–W1–Cl3 = 95.79(13), N1–W1–Cl2 = 83.5(3), N1–W1–Cl3 = 83.1(3), N2–W1–Cl2 =
86.2(3), N2–W1–Cl3 = 86.7(3), N2–W1–N1 = 72.8(4), N2–W1–Cl1 = 91.45(12).
A complex [WOCl4(1,10-phen)] has been claimed [25], but with no reported data. Our attempts
using similar reaction conditions to those used for [WOCl4(2,2’-bipy)] produced a mixture of
products, one of which was identified by an X-ray structure determination as [WO2Cl2(1,10-
7

phen)]⋅CH2Cl2 by comparison of the unit cell parameters with the literature [27]. It is possible
that the more rigid 1,10-phenanthroline is poorly matched to the seven-coordinate tungsten
centre. It is notable that attempts to isolate [WOF4(1,10-phen)] from reaction of
[WOF4(MeCN)] with 1,10-phen failed, with [WO2F2(1,10-phen)] being identified as one major
product [17].
As indicated above, decomposition (probably hydrolysis) of some of the WOCl4 complexes to
WO2Cl2 species was noted, whereas under more forcing condition (higher temperatures, excess
ligand or extended reaction time) reduction to tungsten(V) species sometimes occurs
[1,7,19,28]. During attempts to grow crystals from the [WOCl4(OPR3)] by slow evaporation
from CH2Cl2 solutions. a few white crystals were isolated, which proved to be cyclic {Wn(µ-
O)n} species. Several batches of white crystals were obtained, most with the crystal quality too
poor to merit report, but a few good crystals were obtained on one occasion from the OPMe3
system and the structure is shown in Figure 5.
Figure 5 The structure of [W3O3(µ-O)3Cl6(OPMe3)3]⋅2CH2Cl2 showing the atom numbering scheme
The Me groups on P3 show disorder over two sites, only one is shown. H atoms and the lattice CH2Cl2
molecules are omitted for clarity. Selected bond lengths (Å) and angles (°) are: W1–Cl2 = 2.3491(8),
W1–Cl1 = 2.3397(8), W1–O9 = 2.2211(18), W1–O1 = 2.0817(18), W1–O3 = 1.7651(18), W1–O2 =
1.710(2), W2–Cl4 = 2.3528(7), W2–Cl3 = 2.3522(8), W2–O4 = 2.0715(18), W2–O6 = 1.7669(19),
8

W2–O3 = 2.2301(18), W2– O5 = 1.7167(19), W3–Cl5 = 2.3522(8), W3–Cl6 = 2.3549(8), W3–O9 =
1.7539(18), W3–O6 = 2.2239(18), W3–O7 = 2.0681(19), W3–O8 = 1.715(2), WObW = 152.97(11),
154.90(11), 154.52(11), ObWOb = 86.07(8), 85.01(8), 86.07(8).
The crystals contain W(VI) with a distorted octahedral coordination environment composed of
WO2Cl2(OPMe3) units linked via very asymmetric oxido-bridges into a six-membered ring.
Thus, the W=O group trans to the phosphine oxide with W=O ~ 1.8 Å forms a weak bridge to
a second tungsten (~2.22 Å), distances which may be compared with the terminal W=O of ~
1.7 Å. The remaining bond lengths and angles about the tungsten centre are not significantly
different to those in the other phosphine oxide complexes. Attempts to prepare a bulk sample
of the complex directly by varying the conditions in the WOCl4, O(SiMe3)2, OPMe3 reaction
were unsuccessful.
3. Conclusions
The synthesis of a series of phosphine oxide and pyridyl ligand complexes of WOCl4 and
WSCl4 has been described. Under the mild synthesis conditions used, reduction to lower
oxidation states of tungsten is not significant, although all complexes are hydrolytically
unstable, and must be manipulated and stored under strictly anhydrous conditions. Except for
the 2,2’-bipy complexes, where the small ring chelate produces seven-coordination, the other
complexes are six-coordinate. Comparison of the data from various spectroscopic probes, viz
the IR ν(P=O) data, the coordination shift observed in the 31P{1H} NMR spectra of the
phosphine oxide species, and the d(WOp) bond lengths in the structures, show only small
differences between the corresponding complexes of WOCl4 and WSCl4. The data suggest that
WSCl4 may be a marginally less strong Lewis acid than WOCl4, but the differences in the
various parameters are small. Future work will examine the corresponding complexes of these
two hard W(VI) Lewis acids with much softer sulfur or phosphorus donor ligands, to establish
if the trends are replicated.
4. Experimental
Syntheses were performed by using standard Schlenk and glove-box techniques under a dry N2
atmosphere. WCl6 (Acros organics), O(SiMe3)2 and S(SiMe3)2 (Sigma-Aldrich) were used as
received. Solvents were dried by distillation from CaH2 (CH2Cl2, MeCN) or Na/benzophenone
9

ketyl (toluene, n-hexane). Ligands (2,2’-bipy, 1,10-phen, OPPh3) were obtained from Sigma-
Aldrich and dried by heating in vacuo before use. Pyridine was dried over sodium and freshly
distilled. The diphosphine dioxides, dppmO2 and dppeO2, were made by dry air oxidation of
the corresponding diphosphines in CH2Cl2 solution, catalysed by SnI4 [29] and were checked
for purity by 31P{1H} NMR spectroscopy. They were also dried by heating in vacuo.
Infrared spectra were recorded on a Perkin-Elmer Spectrum 100 spectrometer in the range
1
4000–200 cm1, with samples prepared as Nujol mulls between CsI plates. H NMR spectra
were recorded using a Bruker AV 400 spectrometer and referenced to the residual protio-
resonance of the solvent. 31P{1H} NMR spectra were obtained from CD2Cl2 solutions using a
Bruker AV 400 spectrometer and referenced external 85% H3PO4. Microanalyses on new
compounds were undertaken by London Metropolitan University or Medac.
3.1 [WOCl4]
Following the literature method [23], a solution of (Me3Si)2O (0.82 g, 5.04 mmol) in
dichloromethane (5 mL) was added to a stirred solution of WCl6 (2.0 g, 5.04 mmol) in
dichloromethane (5 mL). The orange solution was stirred for 1 h and the orange precipitate was
filtered off and washed with cold hexane (2 x 1 mL), and dried in vacuo. IR spectrum (Nujol,
cm-1): 889sh W=O, 875s W=O, 381s,br WCl, 326s WCl.
3.2 [WSCl4]
WCl6 (2.5 g, 6.3 mmol) in toluene (5 mL) was chilled to 0oC and hexamethyldisilathane (1.35
g, 6.3 mmol) in toluene (5 mL) was added dropwise over 15 min. The red/brown solution
formed was stirred for 30 min. and taken to dryness in vacuo, resulting in a brown powder. The
brown powder was sublimed in vacuo yielding a red powder on the cold finger. Yield: 0.950
g, 42%. IR spectrum (Nujol, cm1): 556m W=S, 372s WCl.
3.3 [WOCl4(OPPh3)]
A solution of OPPh3 (0.105 g, 0.44 mmol) in dichloromethane (5 mL) was added slowly to a
suspension of WOCl4 (0.150 g, 0.44 mmol) in dichloromethane (5 mL). The clear orange
solution was then stirred for 1 h, concentrated to ~ 5 mL in vacuo, filtered, and the resulting
orange solid washed with hexane (2 x 1 mL), and dried in vacuo. Yield: 0.130 g, 48%. Required
for C18H15Cl4O2PW (619.9): C, 34.85; H, 2.44. Found: C, 35.01; H, 2.44%. IR spectrum (Nujol,
1
cm1): 1135s P=O, 981s W=O, 338s WCl. H NMR (CDCl3): δ = 7.88 (m, [6H]), 7.70 (m,
[3H]), 7.58 (m, [6H]). 31P{1H} NMR (CDCl3): δ = +46.6 (s).
10

3.4 [WOCl4(OPMe3)]
OPMe3 (0.059 g, 0.44 mmol) in dichloromethane (5 mL) was slowly added to a suspension of
WOCl4 (0.150 g, 0.44 mmol) in dichloromethane (5 mL). The yellow solution was then stirred
for 1 h, concentrated to half the volume, filtered and the resulting yellow solid washed with
hexane (2 x 1 mL), and dried in vacuo. Yield: 0.140 g, 73%. Required for C3H9Cl4O2PW
(433.7): C, 8.31; H, 2.09. Found: C, 8.55; H, 2.02%. IR spectrum (Nujol, cm1):1089s,br P=O,
957s W=O, 337s WCl. 1H NMR (CDCl3): δ = 1.88 (d, 2JHP = 13 Hz). 31P{1H} NMR (CDCl3):
δ = +64.2 (s).
3.5 [(WOCl4)2(dppmO2)]
Powdered dppmO2 (0.120 g, 0.29 mmol) in dichloromethane (5 mL) was added slowly to an
orange suspension of WOCl4 (0.200 g, 0.58 mmol) in dichloromethane (5 mL). The clear
orange/brown solution formed was stirred for 1 h, then concentrated to ~ 5mL, filtered and the
orange powder washed with hexane (2 x 1 mL) and dried in vacuo. Yield: 0.264 g, 83%.
Required for C25H22Cl8O4P2W2 (1099.7): C, 27.30; H, 2.02. Found: C, 27.42; H, 2.14%. IR
1
spectrum (Nujol, cm1): 1076m,br P=O, 981s W=O, 338s,br WCl. H NMR (CDCl3): δ =
7.81(m, [8H]), 7.61 (m, [4H]), 7.43 (m, [8H]), 4.62 (t, [2H], 2JH-P = 15.5 Hz). 31P{1H} NMR
(CDCl3): δ = +44.6 (s).
3.6 [(WOCl4)2(dppeO2)]
Was made similarly to [(WOCl4)2(dppmO2)] as a yellow powder. Yield 31%. Required for
C26H24Cl8O4P2W2 (113.7): C, 28.04; H, 2.17. Found: C, 27.96; H, 2.12%. IR spectrum (Nujol,
1
cm1): 1091s P=O, 985s W=O, 337s WCl. H NMR (CDCl3): δ = 7.86 (m, [8H]), 7.70 (m,
[4H]), 7.59 (m, [8H]), 3.15 (br,s, [4H]). 31P{1H} NMR (CDCl3): δ = +53.2 (s).
3.7 [WSCl4(OPPh3)]
OPPh3 (0.078 g, 0.28 mmol) in dichloromethane (2 mL) was slowly added to a red solution of
WSCl4 (0.100 g, 0.28 mmol) in dichloromethane (5 mL). The solution was then stirred for 1
h., concentrated in vacuo to ~ 4 mL. The brown precipitate was filtered off, washed with hexane
(2 x 1 mL) and dried in vacuo. Yield: 0.120 g, 69 %. Required for C18H15Cl4OPSW (636.0):
C, 33.99; H, 2.38. Found: C, 34.14; H, 2.45%. IR spectrum (Nujol, cm1): 1137m P=O, 329s
1
WCl, 310sh WCl. H NMR (CD2Cl2) δ = 7.81 (m, [6H]), 7.68 (t, [3H]), 7.55 (m, [6H]).
31P{1H} NMR (CD2Cl2): δ = +45.9 (s).
3.8 [WSCl4(OPMe3)]
11

A brown powder, made in an analogous way to [WSCl4(OPPh3)]. Yield: 43%. Required for
C3H9Cl4OPSW (449.8): C, 8.01; H, 2.00. Found: C, 8.14; H, 2.14%. IR spectrum (Nujol, cm1):
1
2
1075s,br P=O, 522m W=S, 322s,br WCl. H NMR (CD2Cl2): δ = 1.81 (d, JPH = 13 Hz).
31P{1H} NMR (CD2Cl2): δ = +63.8 (s).
3.9 [(WSCl4)2(dppmO2)]
Dried dppmO2 (0.086 g, 0.21 mmol) in dichloromethane (5 mL) was added slowly to a red
suspension of WSCl4 (0.150 g, 0.42 mmol) in dichloromethane (5 mL). The resulting brown
solution was then stirred for 1 h, concentrated in vacuo and the brown solid filtered off and
rinsed with hexane (2 x 1 mL), and them dried in vacuo. Yield: 0.115 g, 48%. Required for
C25H22Cl8O2P2S2W2 (1131.8): C, 26.53; H, 1.96. Found: C, 26.52; H, 2.06%. IR spectrum
(Nujol, cm1):1074m P=O, 530m W=S, 338sh WCl, 327s WCl. 1H NMR (CD2Cl2): δ = 7.76
(br, [8H]), 7.56 (br, [4H]), 7.43 (br, [8H]), 3.82 (br, [2H]). 31P{1H} NMR (CD2Cl2): δ = +45.4
(s).
3.10 [(WSCl4)2(dppeO2)]
Dried dppeO2 (0.090 g, 0.21 mmol) in dichloromethane (5 mL) was slowly added to a red
suspension of WSCl4 (0.150 g, 0.42 mmol) in dichloromethane (5 mL), when a brown solution
was formed. After 1 h, the solution was concentrated in vacuo, the brown solid filtered off,
washed with hexane (2 x 1 mL) and dried in vacuo. Yield: 0.190 g, 79%. Required for
C26H24Cl8O2P2S2W2 (1145.85): C, 27.25; H, 2.11. Found: C, 27.00; H, 2.02%. IR spectrum
(Nujol, cm1):1077s P=O, 536s W=S, 330s WCl. 1H NMR (CD2Cl2): δ = 7.93 (br, [8H]), 7.66
(br, [4H]), 7.59 (br, [8H]), 2.78 (m, [4H]). 31P{1H} NMR (CD2Cl2) δ = +49.2 (s).
3.11 [WOCl4(C5H5N)]
Pyridine (0.050 g, 0.58 mmol) in toluene (2 mL) was added to a red suspension of WOCl4
(0.200 g, 0.58 mmol). The red solution formed was stirred for 1 h and then taken to dryness in
vacuo to obtain a yellow powder. Yield: 0.120 g, 49%. Required for C5H5Cl4NOW (420.75):
C, 14.27; H, 2.20; N, 3.33. Found: C, 14.23; H, 2.15; N, 3.31%. IR spectrum (Nujol, cm1):
987m W=O, 338s WCl. 1H NMR (CD2Cl2): δ = 9.37 (dd, [2H], JHH = 6.6, 1.5 Hz), 8.06 (tt,
[H], JHH = 7.7, 1.5 Hz), 7.65 (td, [2H], JHH = 6.6, 1.2 Hz).
3.12 [WSCl4(C5H5N)]
Pyridine (0.050 g, 0.58 mmol) in toluene (2 mL) was added to a red solution of WSCl4 (0.200
g, 0.58 mmol). The brown solution formed was stirred for 1 h, and then taken to dryness in
12

vacuo to yield a brown/grey powder. Yield: 0.160 g, 87%. Required for C5H5Cl4NSW (436.8):
C, 13.75; H, 1.15; N, 3.21. Found: C: 14.06, H: 1.20, N: 3.29%. IR spectrum (Nujol, cm1):
1
533s W=S, 334s,br WCl. H NMR (CD2Cl2): δ = 8.78 (br, [2H]), 8.56 (br, [H]), 8.11 (br,
[2H]).
3.13 [WOCl4(2,2’-bipy)]
2,2’-bipy (0.068 g, 0.44 mmol) in dichloromethane (5 mL) was added slowly to an orange
suspension of WOCl4 (150 mg, 0.44 mmol) in dichloromethane (5 mL). The green solution
formed was stirred for 1 h at room temperature and then concentrated to ~ 10mL in vacuo. The
green solid was isolated by filtration, washed with hexane (2 x 1 mL) and dried in vacuo. Yield:
0.067 g, 30%. Required for C10H8Cl4N2OW (499.85): C, 24.11; H, 1.62; N, 5.63. Found: C,
1
24.33; H, 1.73; N, 5.84%. IR spectrum (Nujol, cm1): 970s W=O, 329s,br WCl. H NMR
(CDCl3): δ = 8.99 (d, [2H], JHH = 8.1 Hz), 8.85 (d, [2H], JHH = 4.4 Hz), 8.22 (t, [2H], JHH = 7.8
Hz), 7.66 (t, [2H], JHH = 4.0 Hz).
3.14 [WSCl4(2,2’-bipy)]
2,2’-bipy (0.065 g, 0.42 mmol) in dichloromethane (5 mL) was added slowly to a red
suspension of WSCl4 (0.150 g, 0.42 mmol) in dichloromethane (5 mL). The purple/red solution
was stirred for 1 h, concentrated to ~5 mL and the red-pink powder filtered off, washed with
hexane (2 x 1 mL), and dried in vacuo, yielding a red/pink powder. Yield: 0.165 g, 76%.
Required for C10H8Cl4N2SW (513.9): C, 23.37; H, 1.57; N, 5.45. Found: C, 23.36; H, 1.59; N,
1
5.50%. IR spectrum (Nujol, cm1): 521s W=S, 316s WCl. H NMR (CD2Cl2): δ = 8.97 (d,
[2H], JHH = 8.3 Hz), 8.89 (d, [2H], JHH = 5.1 Hz), 8.27 (t, [2H], JHH = 7.6 Hz), 7.73 (t, [2H],
JHH = 7.6 Hz).
3.15 X-ray experimental
Data collections used a Rigaku AFC12 goniometer equipped with an enhanced sensitivity (HG)
Saturn724+ detector mounted at the window of an FR-E+ SuperBright molybdenum (λ =
0.71073) rotating anode generator with VHF Varimax optics (70 micron focus) with the crystal
held at 100 K (N2 cryostream). Crystallographic parameters are in Table 1. Structure solution
and refinement were performed using SHELX(S/L)97, SHELX-2014/7 [30] and were mostly
straightforward, some minor disorder within one PMe3 group is noted in the structure of
[W3O3(µ-O)3Cl6(OPMe3)3]⋅2CH2Cl2, this was modelled satisfactorily using split C atom site
occupancies. H atoms were added and refined with a riding model.
13

Conflicts
The authors have no conflicts to declare.
Acknowledgements
We thank EPSRC for support through EP/P025137/1 and for a studentship to DLS (XXX).
Appendix A. Supplementary data
Contain the supplementary crystallographic data for this paper. CCDC numbers are 1882209:
[WOCl4(OPPh3)], 1882210: [{WOCl4}2(dppmO2)], 882211: [{WSCl4}2(dppeO2)], 1882212:
[W3O3(µ-O)3Cl6(OPMe3)3].2CH2Cl2, 1883854: [WSCl3(bipy)] .These data can be obtained free
of charge via http://www.ccdc.cam.ac.uk/conts/retrieving.html, or from the Cambridge
Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ UK; Other supplementary
materials include IR and NMR spectra for the complexes. Supplementary data associated with
this article can be found in the online version, at http://.......
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15

Table 1 Crystallographic dataa
Compound
[WOCl4(OPPh3)]
[(WOCl4)2(dppmO2)]
C25H22Cl8O4P2W2
1099.66
[(WSCl4)2dppeO2]
C13H12Cl4OPSW
572.91
Formula
C36H30Cl8O4P2W2
1239.84
triclinic
M
Crystal system
triclinic
triclinic
Space group (no)
P -1 (2)
P -1 (2)
P -1 (2)
a /Å
9.36630(10)
15.4398(2)
16.0484(2)
109.4180(10)
97.1570(10)
105.4190(10)
2051.31(5)
2
10.3428(2)
11.0799(2)
15.3764(2)
81.7770(10)
70.3800(10)
80.1300(10)
1628.27(5)
2
9.1134(5)
9.3623(3)
11.7376(4)
97.087(3)
106.333(4)
112.441(4)
857.70(7)
2
b /Å
c /Å
α /
 /
 /
U /Å3
Z
(Mo-Kα) /mm–1
F(000)
6.241
7.846
7.565
1184
1036
542
Total number reflns
Rint
53470
44544
23334
0.024
0.028
0.055
Unique reflns
8081
9901
5298
No. of params, restraints
GOF
469, 0
1.035
370, 0
1.081
190, 0
1.083
R1, wR2 [I > 2σ(I)]b
0.014, 0.033
0.016, 0.033
0.017, 0.036
0.022, 0.036
0.026, 0.063
0.031, 0.064
R1, wR2 (all data)b
b
a
common data: wavelength (Mo-Kα) = 0.71073 Å; θ(max) = 27.5°;
wR2=[Σw(Fo2-Fc2)2/ΣwFo4]1/2
R1 = Σ||Fo|-|Fc||/Σ|Fo|;
17

Table 1 Continued
Compound
[W3O3(µ-O)3Cl6(OPMe3)3]. 2CH2Cl2 [WSCl3(2,2’-bipy)]
Formula
C11H31Cl10O9P3W3
1306.32
monoclinic
P21/c (14)
19.1399(5)
11.2360(2)
18.2845(5)
90
C10H8Cl3N2SW
478.44
M
Crystal system
triclinic
P1 (1)
Space group (no.)
a /Å
6.6843(2)
8.1998(2)
12.3744(4)
74.743(2)
89.939(2)
89.988(2)
654.34(3)
2
b /Å
c /Å
α /
116.616(3)
90
 /
 /
U /Å3
3515.49(17)
4
Z
(Mo-Kα) /mm–1
F(000)
10.724
9.575
2424
446
Total number reflns
Rint
37791
19122
0.030
0.028
Unique reflns
No. of params, restraints
GOF
6842
5139
336, 0
278, 3
1.028
1.131
R1, wR2 [I > 2σ(I)]b
R1, wR2 (all data)b
0.016, 0.030
0.020, 0.030
0.039, 0.070
0.030, 0.071
18

Two series of W(VI) complexes based upon WOCl4 and WSCl4 fragments with phosphine oxide and N-
heterocyclic ligands are reported and their spectroscopic and structural features assessed.
19