Syntheses, Crystal Structures, Spectroscopic Characterization, and Electrochemical Studies of the Ditungsten(III) Complexes Cl3W (μ-L)3WCl3 and [Cl3W(μ-L)2 (μ-Cl)WCl3] (L = 1,4-Dithiane,1,4-Thioxane, pms = Pentamethylene Sulfide). C-S Bond Cleavage of the Bridging Thioether(s) in Cl3W (μ-L)3WCl

Article abstract of DOI:10.1021/ic971542t

Reduction of WCl₄ with 1 equiv of sodium amalgam, in the presence of either a refluxing toluene or neat solution of the desired thioether, produces a mixture of Cl₃W(μ-L)₃WCl₃ (L = 1,4-dithiane (1), 1,4-thioxane (2), pms = pentamethylene sulfide (3)) and [Na][Cl₃W(μ-L)₂(μ-Cl)WCl₃] (L = 1,4-dithiane (4), 1,4-thioxane (5), pms (6)). 4 and 5 could be converted to 1 and 2, respectively, in the presence of excess L in refluxing toluene. The structures of 1, 2, 3, 7, and 8 have been solved. 1, 2, and 3 are the first reported crystal structures for ditungsten-(III) tris-bridged cyclic thioether complexes. Crystal data are as follows: for an acetone solvate of 1, monoclinic space group P2₁ln (No. 14), a = 12.518(3) A?, b = 9,475(2) A?, c = 27.408(3) A?, β= 93.34(1)°, Z = 4; for an acetone solvate of 2, tetragonal space group P4/ncc (No. 130), a = 25.7603(3) A?, b = 25.7603(3) A?, c -18.6771(2) A?,Z= 16; for a hexane solvate of 3, monoclinic space group P2₁ln (No. 14), a = 11.874(4) A?, b = 21.823(3) A?, c = 12.545(3) A?, b = 100,46(3)°, Z = 4; for an acetonitrile solvate of 7, monoclinic space group P2₁/c (No. 14), a = 9.704(5) A?, b = 28.241(7) A?. c = 15.480(5) A?, β= 98.55(4)°, Z = 4; for a chloroform solvate of 8, monoclinic space group P2₁/a (No. 14), a = 13.531(4) A?, b = 25.207(5) A?, c = 14.083(3) A?, β= 115.57(2)°, Z = 4. 1, 2, and 3 were all shown to undergo C-S bond cleavage of a bridging thioether by reaction with [PPh₄][Sptol] (ptol = 4-methyl phenyl) to afford the anionic complexes [PPh₄][Cl₃W(μ-S(CH₂CH₂) ₂E)₂(-μSCH₂-CH₂ECH ₂CH₂Sptol)WCl₃] (E = S (9), O (10), CH₂ (12)). 1, 2, 7, and 8 undergo reversible one-electron reductions.

Full text of DOI:10.1021/ic971542t

Inorg. Chem. 1998, 37, 6023-6029
6023
Syntheses, Crystal Structures, Spectroscopic Characterization, and Electrochemical Studies
of the Ditungsten(III) Complexes Cl3W(µ-L)3WCl3 and [Cl3W(µ-L)2(µ-Cl)WCl3]- (L )
1,4-Dithiane, 1,4-Thioxane, pms ) Pentamethylene Sulfide). C-S Bond Cleavage of the
Bridging Thioether(s) in Cl3W(µ-L)3WCl3
P. Michael Boorman,* Naomi L. Langdon, Vivian J. Mozol, and Masood Parvez
Department of Chemistry, University of Calgary, Calgary, Alberta, Canada, T2N 1N4
Glenn P. A. Yap
University of Ottawa, X-ray Laboratory, Ottawa, Ontario, Canada, K1N 6N5
ReceiVed December 9, 1997
Reduction of WCl4 with 1 equiv of sodium amalgam, in the presence of either a refluxing toluene or neat solution
of the desired thioether, produces a mixture of Cl3W(µ-L)3WCl3 (L ) 1,4-dithiane (1), 1,4-thioxane (2), pms )
pentamethylene sulfide (3)) and [Na][Cl3W(µ-L)2(µ-Cl)WCl3] (L ) 1,4-dithiane (4), 1,4-thioxane (5), pms (6)).
4 and 5 could be converted to 1 and 2, respectively, in the presence of excess L in refluxing toluene. The
structures of 1, 2, 3, 7, and 8 have been solved. 1, 2, and 3 are the first reported crystal structures for ditungsten-
(III) tris-bridged cyclic thioether complexes. Crystal data are as follows: for an acetone solvate of 1, monoclinic
space group P21/n (No. 14), a ) 12.518(3) Å, b ) 9.475(2) Å, c ) 27.408(3) Å, â ) 93.34(1)°, Z ) 4; for an
acetone solvate of 2, tetragonal space group P4/ncc (No. 130), a ) 25.7603(3) Å, b ) 25.7603(3) Å, c ) 18.6771-
(2) Å, Z ) 16; for a hexane solvate of 3, monoclinic space group P21/n (No. 14), a ) 11.874(4) Å, b ) 21.823(3)
Å, c ) 12.545(3) Å, â ) 100.46(3)°, Z ) 4; for an acetonitrile solvate of 7, monoclinic space group P21/c (No.
14), a ) 9.704(5) Å, b ) 28.241(7) Å, c ) 15.480(5) Å, â ) 98.55(4)°, Z ) 4; for a chloroform solvate of 8,
monoclinic space group P21/a (No. 14), a ) 13.531(4) Å, b ) 25.207(5) Å, c ) 14.083(3) Å, â ) 115.57(2)°,
Z ) 4. 1, 2, and 3 were all shown to undergo C-S bond cleavage of a bridging thioether by reaction with
[PPh4][Sptol] (ptol ) 4-methyl phenyl) to afford the anionic complexes [PPh4][Cl3W(µ-S(CH2CH2)2E)2(µ-SCH2-
CH2ECH2CH2Sptol)WCl3] (E ) S (9), O (10), CH2 (12)). 1, 2, 7, and 8 undergo reversible one-electron reductions.
Introduction
Scheme 1
We reported previously the synthesis and characterization of
the ditungsten(III) complex Cl3W(tht)3WCl3 (tht ) tetrahy-
drothiophene (12)).1 Though the W2S3Cl6 core of the molecule
was found to be resistant to nucleophilic attack, the complex
was significantly modified, via C-S bond cleavage of a bridging
thioether, to produce anionic, functionalized thiolate complexes
(Scheme 1).2
We are presently involved in developing the chemistry related
to thioether ring-opening since the direct syntheses of similar
functionalized thiolate species has proved to be difficult. In
particular we are interested in whether the anionic functionalized
thiolates in ditungsten(III) complexes can be used to bind a
secondary metal center. The ultimate goal is to determine their
use as metalloligands for neutral or cationic late transition-metal
species. One of the main considerations in the evolution of
these complexes as metalloligands is the ability to design
specific binding sites, that is, modify the functionality of the
thiolate. Attempts to achieve this have been made by varying
the type of nucleophile used or the nature of the tris-ring
thioether bridged precursors. With respect to the latter, this
paper reports the preparation and characterization of three new
tris-bridged cyclic thioether ditungsten(III) complexes, 1, 2, and
3, followed by investigation into the possibility of nucleophilic
attack resulting in their ring-opening.
(1) Boorman, P. M.; Gao, X.; Freeman, G. K. W.; Fait, J. F. J. Chem.
Soc., Dalton Trans. 1991, 115-120.
(2) Boorman, P. M.; Gao, X.; Fait, J. F.; Parvez, M. Inorg. Chem. 1991,
30, 3886-3893.
The successful syntheses of 1-3 were accompanied by the
isolation and characterization of the bis-ring thioether bridged
ditungsten(III) complexes (4-6).
10.1021/ic971542t CCC: $15.00 © 1998 American Chemical Society
Published on Web 10/28/1998

6024 Inorganic Chemistry, Vol. 37, No. 23, 1998
Boorman et al.
Cl3W(µ-1,4-dithiane)3WCl3 (1) and [Na][Cl3W(µ-1,4-dithiane)2-
(µ-Cl)WCl3] (4). Several procedures were attempted. WCl4 (0.500
g, 1.5 mmol), Na/Hg (2% w/w, 1.76 g; 0.035 g Na), dithiane (0.800 g,
6.7 mmol), and toluene (∼5 mL) were placed in a Schlenk tube and
refluxed for 45 min, 24 h, and 1 week (the 45 min reaction was locally
heated using a heat gun source, the 24 h and 1 week reactions were
heated using a heating mantle with Variac). After cooling to room
temperature, diethyl ether (50 mL) was added then the supernatant
decanted off and the residue was washed with diethyl ether (2 × 100
mL). Extraction using acetone afforded a red solution, the solvent was
removed in vacuo, and the red residue washed with diethyl ether (2 ×
50 mL). Yields for the respective reaction times were 100, 750, and
Scheme 2
1
400 mg. The H NMR spectra indicated the presence of two species,
1 and 4. It was found that 1 could be isolated by extraction of the red
residue using CH2Cl2. Purification of 1 and 4 required repeated
crystallizations from CH2Cl2 and acetone, respectively. Data given
below is for the 24 h reaction which gave the best overall yield.
Data for 1: yield, 360 mg (25% of 100% tris). Anal. Calcd for
C12H24S6Cl6W2: C, 15.31; H, 2.57. Found: C, 15.34; H, 2.30. 1H
NMR (CD3CN, ambient, δ): 3.99 (m, 12H, µ-dithiane RH’s), 3.55 (m,
12H, µ-dithiane âH’s). 13C{1H} NMR (CD3CN, ambient, δ): 46.96
(s, 6C, µ-dithiane RC’s), 29.09 (s, 6C, µ-dithiane âC’s).
Scheme 3
Data for 4: yield, 360 mg (27% of 100% bis). 1H NMR (CD3CN,
ambient, δ): δ 4.13 (m, 4H, µ-dithiane RH’s), 3.70 (m, 4H, µ-dithiane
RH’s), 3.68 (m, 4H, µ-dithiane âH’s), 3.57 (m, 4H, µ-dithiane âH’s).
13C{1H} NMR (CD3CN, ambient, δ): 47.93 (s, 2C, µ-dithiane RC’s),
47.65 (s, 2C, µ-dithiane RC’s), 29.34 (s, 2C, µ-dithiane âC’s), 29.31
(s, 2C, µ-dithiane âC’s). Negative FAB-MS: m/z 857 (Cl3W(µ-1,4-
dithiane)2(µ-Cl)WCl3), 617 (Cl3W(µ-Cl)WCl3).
Cl3W(µ-1,4-thioxane)3WCl3 (2) and [Na][Cl3W(µ-1,4-thioxane)2-
(µ-Cl)WCl3] (5). WCl4 (0.500 g, 1.5 mmol), Na/Hg (2% w/w, 1.76
g; 0.035 g Na), and 1,4-thioxane (3 mL) were reacted together under
refluxing conditions. A reaction time of 25 min produced the best
overall yield.
Data for 2: yield, 210 mg (15.3% of 100% tris). Anal. Calcd for
1
C12H24S3O3Cl6W2: C, 16.14; H, 2.71. Found: C, 16.68; H, 2.57. H
NMR (CD3CN, ambient, δ): 4.49 (m, 12H, µ-thioxane âH’s), 3.75
(m, 12H, µ-thioxane RH’s). 13C{1H} NMR (CD3CN, ambient, δ):
67.88 (s, 6C, µ-thioxane âC’s), 41.87 (s, 6C, µ-thioxane RC’s).
Negative FAB-MS: m/z 892 (Cl3W(µ-1,4-thioxane)3WCl3).
Data for 5: yield, 1.050 g (81% of 100% bis). Anal. Calcd for
C8H16S2O2Cl7W2Na: C, 11.34; H, 1.90. Found: C, 11.06; H, 1.97.
1H NMR (CD3CN, ambient, δ): 4.61 (m, 4H, µ-thioxane âH’s), 4.52
(m, 4H, µ-thioxane âH’s), 3.90 (m, 4H, µ-thioxane RH’s), 3.45 (m,
4H, µ-thioxane RH’s). 13C{1H} NMR (CD3CN, ambient, δ): 68.38
(s, 2C, µ-thioxane âC’s), 68.19 (s, 2C, µ-thioxane âC’s), 42.98 (s, 2C,
µ-thioxane RC’s), 42.78 (s, 2C, µ-thioxane RC’s). Negative FAB-
MS: m/z 825 (Cl3W(µ-1,4-thioxane)2(µ-Cl)WCl3), 617 (Cl3W(µ-Cl)-
WCl3).
Experimental Section
General Procedures. All manipulations were carried out using
standard glovebox and Schlenk techniques under an atmosphere of dry
N2 or argon. Solvents were dried over the appropriate drying agents,
distilled under nitrogen onto molecular sieves, and degassed using argon
before use.3 Thietane (trimethylene sulfide), 1,4-thioxane, and pms,
as purchased from Aldrich, were dried over molecular sieves and
degassed, via freeze-thaw techniques under argon, prior to use.
Dithiane, purchased from Aldrich, was purified by sublimation under
vacuum onto a coldfinger. WCl4 was prepared by reduction of WCl6
with 0.5 mol of W(CO)6 in refluxing chlorobenzene for 14 h as per
literature instructions,4 then purified over 24 h by sublimation of volatile
impurities at 225 °C in an evacuated and flame-sealed Pyrex tube.
Elemental analyses were performed by the University of Calgary,
Department of Chemistry, Analytical Services Laboratory. 1H and
13C{1H} NMR spectra were recorded in CD3CN or CDCl3 using a
Bru¨ker ACE-200 or ACE-400 NMR spectrometer (designation of
the H and C atoms provided in Schemes 2 and 3).
Synthetic Procedures. Cl3W(µ-L)3WCl3 (L ) 1,4-dithiane (1),
1,4-thioxane (2) and pms (3)) and [Na][Cl3W(µ-L)2(µ-Cl)WCl3] (L
) 1,4-dithiane (4), 1,4-thioxane (5), pms (6)). The previously
established synthetic route to preparing tris-thioether bridged ditungsten-
(III) complexes involves the reduction of WCl4 using sodium amalgam
in the presence of refluxing neat thioether.1 The same procedure was
employed toward the preparation of 1-3 and required a variation in
reaction times and the use of toluene as a solvent in the case of the
highly volatile solid dithiane. The formation of 1-3 was always
accompanied by the formation of the anionic bis-thioether bridged
ditungsten(III) complexes, 4-6. The complete preparative procedure
for the dithiane complexes is given below as an example.
Cl3W(µ-pms)3WCl3 (3) and [Na][Cl3W(pms)2(µ-Cl)WCl3] (6).
WCl4 (0.500 g, 1.5 mmol), Na/Hg (2% w/w, 1.76 g, 0.035 g Na), and
pms (5 mL) were reacted together under refluxing conditions.
reaction time of 45 min produced the best overall yield.
A
Data for 3: yield, 1.00 g (86%). Anal. Calcd for C15H30S3Cl6W2:
C, 20.3; H, 3.41. Found: C, 19.6; H, 3.43. 1H NMR (CD3CN, ambient,
δ): 3.66 (m, 12H, µ-pms RH’s), 2.50 (m, 12H, µ-pms âH’s), 1.77 (m,
6H, µ-pms γH’s).
Data for 6: yield, 110 mg (9.5%). 1H NMR (CD3CN, ambient, δ):
3.75 (m, 4H, µ-pms RH’s), 3.57 (m, 4H, µ-pms RH’s), 2.90 (m, 4H,
µ-pms âH’s), 2.78 (m, 4H, µ-pms âH’s), 2.09 (m, 4H, µ-pms γH’s).
13C{1H} NMR (CDCl3, ambient, δ): 44.89 (m, 2C, µ-pms RC’s), 44.78
(m, 2C, µ-pms RC’s), 26.26 (m, 4C, µ-pms âC’s), 23.48 (m, 2C, µ-pms
γC’s).
Attempts to Prepare Cl3W(µ-thietane)3WCl3. WCl4 (0.500 g, 1.5
mmol), Na/Hg (2% w/w, 1.76 g, 0.035 g Na), and thietane (5 mL)
were reacted together. Room-temperature reactions of up to 1 month
are shown to result in no reaction. Reactions performed at or just below
reflux, even for a very short time (10 min), were shown to result in the
formation of a brown insoluble polymeric material.
(3) Perrin, D. D.; Armarego, W. L. F. Purification of Laboratory
Chemicals, 3rd ed.; Pergamon Press: Oxford, 1989.
(4) Schaefer King, M. A.; McCarley, R. W. Inorg. Chem. 1973, 12, 1972.
Reaction of [Na][Cl3W(µ-L)2(µ-Cl)WCl3] (L ) 1,4-Dithiane (4),
1,4-Thioxane (5)) and Excess L. The general procedure was to reflux

Studies of Ditungsten(III) Complexes
Inorganic Chemistry, Vol. 37, No. 23, 1998 6025
the desired bis-thioether complex in the presence of excess L from 1
to 24 h (in the case of dithiane, included was 10 mL toluene, CH2Cl2,
or CH3CN). The solvent, when necessary, was decanted off, and the
residue or slurry was washed with Et2O (3 × 20 mL) to remove excess
L and then extracted first with CH2Cl2 to remove the desired tris
complex and then with acetone to recover unreacted bis complex.
For reaction of 4 (100 mg, 1.1 × 10-1 mmol) with dithiane (100
mg, 8.3 × 10-1 mmol), the best percent conversion to 1 is 50% after
6 h in refluxing toluene.
3.73 (m, 2H, c) ppm; 3.62 (m, 2H, b), 2.32 (s, 3H, ptol methyl H’s).
13C{1H} NMR (CD3CN, ambient, δ): 45.06 (s, 1C, µ-thioxane RC’s),
43.80 (s, 1C, µ-thioxane RC’s), 43.35 (s, 1C, µ-thioxane RC’s), 43.27
(s, 1C, µ-thioxane RC’s), 41.00 (s, 1C, d), 72.88 (s, 1C, c), 70.34 (s,
1C, b), 34.51 (s, 1C, a), 21.10 (s, 1C, ptol methyl C’s), 68.39 (s, 2C,
µ-thioxane âC’s), 68.30 (s, 1C, µ-thioxane âC’s), 68.12 (s, 1C,
µ-thioxane âC’s). Negative FAB-MS: m/z 1015 (Cl3W(µ-1,4-thiox-
ane)2(µ-S(CH2)2O(CH2)2Sptol)WCl3), 807 (Cl3W(µ-S(CH2)2O(CH2)2-
Sptol)WCl3).
For the reaction of 5 (100 mg, 1.2 × 10-1 mmol) with thioxane (3
mL), best percent conversion to 2 is 20% after a 4 h reflux.
[PPh4][Cl3W(µ-L)2(µ-Cl)WCl3] (L ) 1,4-Dithiane (7), 1,4-Thiox-
ane (8)). 4 and 5 were reacted with PPh4Cl in CH2Cl2 (20 mL) at
room temperature over a 24 h period. The solvent was then removed
[PPh4][Cl3W(µ-pms)2(µ-S(CH2)5Sptol))WCl3] (11). 3 (50 mg, 5.6
× 10-2 mmol) was reacted with [PPh4]Sptol (26 mg, 5.6 × 10-2 mmol)
under refluxing conditions for 48 h. Yield: 67 mg (88%); Anal. Calcd
for C46H57S4W2Cl6P: C, 40.91; H, 4.25. Found: C, 37.57; H 4.00. 1H
NMR (CD3CN, ambient, δ): 8.0-7.7 (m, 20H, PPh4 aromatic H’s),
7.25 (d, 2H, ptol aromatic H’s), 7.15 (d, 2H, ptol aromatic H’s), 3.74
(m, 2H, µ-pms RH’s), 3.62 (m, 2H, µ-pms RH’s), 3.47 (m, 6H, µ-pms
R and d H’s), 2.91 (t, 2H, a), 2.46 (m, 8H, µ-pms â and d H’s), 2.31
(s, 3H, ptol methyl H’s), 1.75 (m, 6H, µ-pms γ and c H’s), 1.60 (m,
4H, b and e). 13C{1H} NMR (CD3CN, ambient, δ): 51.93 (s, 1C, µ-pms
RC’s), 50.94 (s, 1C, µ-pms RC’s), 50.65 (s, 1C, µ-pms RC’s), 50.25
(s, 1C, µ-pms RC’s), 44.67 (s, 1C, d), 38.65 (s, 1C, a) 37.13 (s, 1C, c),
34.13 (s, 1C, b), 33.54 (s, 1C, e), 31.75 (s, 1C, µ-pms âC’s), 31.56 (s,
1C, µ-pms âC’s), 31.50 (s, 1C, µ-pms âC’s), 31.42 (s, 1C, µ-pms âC’s),
28.10 (s, 1C, µ-pms γC’s), 27.94 (s, 1C, µ-pms γC’s), 21.75 (s, 1C,
ptol CH3).
i
in vacuo and the residue washed first with PrOH (2 × 20 mL) to
remove unreacted PPh4Cl and then with Et2O (3 × 20 mL) to remove
i
excess PrOH.
Data for 7: 4 (100 mg 1.1 × 10-1 mmol) was reacted with PPh4Cl
(43 mg, 1.1 × 10-1 mmol). Yield: 100 mg (74%). Anal. Calcd for
C32H16S4Cl7W2P: C, 32.12; H, 3.03. Found: C, 32.65; H, 2.79. 1H
NMR (CD3CN, ambient, δ): 4.12 (m, 4H, µ-dithiane RH’s), 3.54 (m,
4H, µ-dithiane RH’s), 3.70 (m, 4H, µ-dithiane âH’s), 3.66 (m, 4H,
µ-dithiane âH’s). 13C{1H} NMR (CD3CN, ambient, δ): 47.94 (s, 2C,
µ-dithiane RC’s), 47.88 (s, 2C, µ-dithiane RC’s), 29.32 (s, 2C,
µ-dithiane âC’s), 29.29 (s, 2C, µ-dithiane âC’s).
Data for 8: 5 (100 mg, 1.2 × 10-1 mmol) was reacted with PPh4Cl
(44 mg, 1.2 × 10-1 mmol). Yield: 105 mg (77%). Anal. Calcd for
C32H36S2O2Cl7W2P: C, 33.00; H, 3.12. Found: C, 32.95; H, 3.08. 1H
NMR (CD3CN, ambient, δ): 3.89 (m, 4H, µ-thioxane RH’s), 3.44 (m,
4H, µ-thioxane RH’s), δ 4.59 (m, 4H, µ-thioxane âH’s), 4.50 (m, 4H,
µ-thioxane âH’s). 13C{1H} NMR (CD3CN, ambient, δ): 42.95 (s, 2C,
µ-thioxane RC’s), 42.75 (s, 2C, µ-thioxane RC’s), 68.32 (s, 2C,
µ-thioxane âC’s), 68.14 (s, 2C, µ-thioxane âC’s). Negative FAB-
MS: m/z 825 (Cl3W(µ-1,4-thioxane)2(µ-Cl)WCl3), 617 (Cl3W(µ-Cl)-
WCl3).
Reactions with [PPh4]Sptol. In a typical reaction, 50 mg of the
desired complex, 1-8, and an equimolar amount of [PPh4]Sptol were
weighed into a Schlenk tube in a glovebox. The Schlenk tube was
evacuated and charged with argon. To this was cannulated over CH3-
CN (10-20 mL). Reaction times varied from 12 to 48 h. The solutions
containing 1 and 2 were stirred at room temperature and those
containing 3-6 while refluxing. After the desired reaction time, the
solution was filtered by gravity through a sintered glass frit (size D)
and the solvent removed in vacuo. The red residues were washed with
diethyl ether (2 × 10 mL) and dried in vacuo.
Crystal Structure Determinations. A red prism of 1 (0.20 × 0.20
× 0.20 mm) was grown by slow evaporation of an acetone solution. A
red prism of 2 (0.10 × 0.10 × 0.10 mm) was grown by preparing an
acetone solution, adding approximately 10% v/v diethyl ether to this
solution, and then storing this mixture overnight at -10 °C. A red
prism of 3 (0.35 × 0.18 × 0.12 mm) was obtained by slow evaporation
of a CH2Cl2 solution with approximately 10% v/v hexane added. A
red-brown prism of 7 (0.35 × 0.30 × 0.10 mm) was grown by slow
evaporation of an acetonitrile solution. A red prism of 8 (0.37 × 0.20
× 0.15 mm) was obtained by slow evaporation of a chloroform solution.
1, 3, 7, and 8 were mounted on glass fibers for data collection on
the University of Calgary’s Rigaku AFC6S diffractometer with graphite-
monochromated Mo KR radiation. Cell constants and an orientation
matrix for data collection were obtained from a least-squares refinement
using the setting angles of 25 carefully centered reflections within the
range ∼18 < 2θ < ∼25°. The data were collected using the ω-2θ
scan techniques to a maximum 2θ value of 50.1°. The diameter of the
incident beam collimator was 1.0 mm, the crystal-to-detector distance
was 400 mm, and the detector aperture was 9.0 × 13.0 mm (horizontal
× vertical). Empirical absorption corrections, based on azimuthal scans
of several reflections, were applied. All data were corrected for Lorentz
and polarization effects. A linear correction factor was also applied to
the data to account for fluctuations in the standards over the course of
data collection ((1) +1.93%, (3) -1.68%, (7) -6.91%, (8) -1.15%).
Correction for secondary extinction was applied for structures 1 and 7
(6.96129 × 10-8 and 2.61305 × 10-8, respectively). The structures
were solved by direct methods5 and expanded using Fourier techniques.6
All non-hydrogen atoms were refined anisotropically except for the C
atoms which were refined isotropically. Hydrogen atoms were included
but not refined. Neutral atom scattering factors were taken from Cromer
and Waber.7 Anomalous dispersion effects were included in Fcalc;8 the
values for ∆f ′ and ∆f′′ were those of Creagh and McAuley.9 The values
[PPh4][Cl3W(µ-1,4-dithiane)2(µ-S(CH2)2S(CH2)2Sptol))WCl3] (9).
1 (50 mg, 5.3 × 10-2 mmol) was reacted with [PPh4]Sptol (25 mg, 5.4
× 10-2 mmol). Yield: 60 mg (80%). Anal. Calcd for C43H51S7W2-
Cl6P: C, 36.77; H, 3.66. Found: C, 36.52; H, 3.82. 1H NMR (CD3-
CN, ambient, δ): 8.0-7.7 (m, 20H, PPh4 aromatic H’s), 7.31 (d, 2H,
ptol aromatic H’s), 7.19 (d, 2H, ptol aromatic H’s), 4.00 (m, 2H,
µ-dithiane RH’s), 3.88 (m, 2H, µ-dithiane RH’s), 3.79 (m, 2H,
µ-dithiane RH’s), 3.71 (m, 2H, µ-dithiane RH’s), 3.56 (m, 6H,
µ-dithiane âH’s), 3.49 (m, 2H, µ-dithiane âH’s), 3.60 (m, 2H, d), 3.16
(m, 2H, a), 2.90 (m, 2H, c), 2.80 (m, 2H, b), 2.32 (s, 3H, ptol methyl
H’s). 13C{1H} NMR (CD3CN, ambient, δ): 50.21 (s, 1C, µ-dithiane
RC’s), 48.87 (s, 1C, µ-dithiane RC’s), 48.81 (s, 1C, µ-dithiane RC’s),
47.93 (s, 1C, µ-dithiane RC’s), 41.81 (s, 1C, d), 35.22 (s, 1C, c), 34.32
(s, 1C, b), 32.39 (s, 1C, a), 29.55 (s, 1C, µ-dithiane âC’s), 29.37 (s,
1C, µ-dithiane âC’s), 29.31 (s, 1C, µ-dithiane âC’s), 29.22 (s, 1C,
µ-dithiane âC’s), 21.12 (s, 1C, ptol methyl C’s).
[PPh4][Cl3W(µ-1,4-thioxane)2(µ-S(CH2)2O(CH2)2Sptol))WCl3] (10).
2 (50 mg, 5.6 × 10-2 mmol) was reacted with [PPh4]Sptol (26 mg, 5.6
× 10-2 mmol). Yield quantitative as shown by 1H NMR of the reaction
mixture. Yield: 53 mg (71%) Anal. Calcd for C43H51S4O3W2Cl6P:
C, 38.07; H, 3.79. Found: C, 38.39; H, 3.69. 1H NMR (CD3CN,
ambient, δ): 8.0-7.6 (m, 20H, PPh4 aromatic H’s), 7.29 (d, 2H, ptol
aromatic H’s), 7.13 (d, 2H, ptol aromatic H’s), 3.43 (m, 2H, µ-thioxane
RH’s), 3.46 (m, 2H, µ-thioxane RH’s), 3.62 (m, 2H, µ-thioxane RH’s),
3.75 (m, 2H, µ-thioxane RH’s), 4.58 (m, 6H, µ-thioxane RH’s), 4.43
(m, 2H, µ-thioxane RH’s), 3.63 (m, 2H, d) ppm; 3.08 (m, 2H, a) ppm;
(5) SIR92. Altomare, A.; Burla, M. C.; Camalli, M.; Cascarano, M.;
Giocovazzo, C.; Guagliardi, A.; Polidori, G. J. Appl. Cryst. 1996, in
press.
(6) DIRDIF94. Beurskens, P. T.; Admiraal, G.; Beurskens, G.; Bosman,
W. P.; deGelder, R.; Israel, R.; Smits, J. M. M. The DIRDIF-94
program systems; Technical Report of the Crystallography Labora-
tory: University of Nijmegen: The Netherlands, 1994.
(7) Cromer, D. T.; Waber, J. T. International Tables for X-ray Crystal-
lography; The Kynoch Press: Birmingham, England, 1974. Table 2.2
A, Vol. IV.
(8) Ibers, J. A., Hamilton, W. C. Acta Crystallogr. 1964, 17, 781.
(9) Creagh, D. C.; McAuley, W. J. International Tables for X-ray
Crystallography; Wilson, A. J. C., Ed.; Kluwer Academic Publish-
ers: Boston, 1992; Vol. C, Table 4.2.6.8, pp 219-222.

6026 Inorganic Chemistry, Vol. 37, No. 23, 1998
Boorman et al.
Table 1. Crystallographic Data for Cl3W(µ-L)3WCl3 [L ) 1,4-Dithiane (1), 1,4-Thioxane (2), pms (3)],
[PPh4][Cl3W(µ-1,4-dithiane)2(µ-Cl)WCl3] (7), and [PPh4][Cl3W(µ-1,4-thioxane)2(µ-Cl)WCl3] (8)
(1)
(2)
(3)
(7)
(8)
chemical formula
C18H36O2S6Cl6W2
acetone solvate
1057.26
P21/n (14)
12.518(3)
9.475(2)
27.408(3)
93.34(1)
3245.3(9)
4
C13.5H27O3.5S3Cl6W2
acetone solvate
921.93
P4/ncc (130)
25.7603(3)
25.7603(3)
18.6771(2)
90
12394.0(2)
16
1.976
81.52
Mo KR, 0.710 73
25(2)
C16H33.5Cl6S3W2
hexane solvate
908.54
P21/n (14)
11.874(4)
21.823(3)
12.545(3)
100.46(3)
3196(1)
C34H39S4Cl7PW2N
acetonitrile solvate
1236.77
P21/c (14)
9.704(5)
28.241(7)
15.480(5)
98.55(4)
4195(2)
4
1.96
61.96
C33H37S2O2Cl10PW2N
chloroform solvate
1282.98
P21/a (14)
13.531(4)
25.207(5)
14.083(3)
115.57(2)
4333(2)
fw (g/mol)
space group (no.)
a (Å)
b (Å)
c (Å)
â (°)
V (Å3)
Z
4
4
F
calc (g/cm3)
2.16
79.89
1.888
79.00
1.967
60.91
µ (cm-1
)
radiation, λ (Å)
Mo KR, 0.710 69
Mo KR, 0.710 69
Mo KR, 0.710 69
Mo KR, 0.710 69
temp (°C)
-103.0
-73.0
-103.0
-103
a
R, Rw
0.046, 0.048
0.0763, 0.1309
0.051, 0.049
0.065, 0.064
0.0811, 0.0869
2
a For structures 1, 3, 7, and 8, R ) ∑||Fo| - |Fc||/∑|Fo|; Rw ) (∑ω(|Fo| - |Fc|)2/∑ωFo )1/2; ω ) 1/σ2(Fo). For structure 2, R ) ∑|(Fo -
2
Fc)|/∑(Fo); Rw ) ∑[ω(Fo - Fc2)2].
Table 2. Selected Reactivity Data for Reactions of WCl4 with
Excess Thioether
for the mass attenuation coefficients are those of Creagh and Hubbell.10
All calculations were performed using the teXsan crystallographic
software package.11
1,4-dithiane
1,4-thioxane
pms
85
Due to the very small size of the crystals obtained for 2, they were
sent to the University of Windsor for structure determination using a
CCD diffractometer. A suitable single crystal was selected and mounted
with epoxy cement on a glass fiber. Unit-cell parameters were
calculated from reflections obtained from 60 data frames collected at
different sections of the Ewald sphere. Reflections were collected in
the range 1.12 < 2θ < 21.00°. The systematic absences in the
diffraction data and the determined unit cell parameters were uniquely
consistent for the reported space group. A semiempirical absorption
correction was applied based on redundant data at varying effective
azimuthal angles. A cocrystallized molecule of acetone solvent is
located at a 2-fold axis. All non-hydrogen atoms were refined with
anisotropic displacement coefficients. All hydrogen atoms were treated
as idealized contributions. The structure was solved by direct methods,
completed by subsequent Fourier syntheses and refined with full-matrix
least-squares methods. All scattering factors and anomalous dispersion
coefficients are contained in the SHELXTL 5.03 program library
(Sheldrick, G. M. Madison, WI).
overall yield (%)
ratio tris:bis (%)
reaction time
50
100
50:50
24 h
20:80
25 min
90:10
45 min
were used, decomposition occurred to yield a brown polymeric
material. This result was not surprising as thermal ring-opening
and subsequent oligomerization of metal bridging thietanes is
known.12
Tris-thioether complexes of 1,4-dithiane, 1,4-thioxane, and
pms (1-3), respectively, were all prepared successfully. How-
ever, their production was accompanied by that of the anionic
bis-thioether bridged complexes (4-6). Syntheses differ in
overall yields, product distribution and reaction time as shown
in Table 2. High overall yields and short reaction times reflect
the use of liquid thioethers. The reasons for the varying product
distribution is unknown.
A crude separation of the tris- and bis-thioether complexes
can generally be accomplished by first extracting the tris-
complexes from the reaction slurry using CH2Cl2 then extracting
a mixture, comprised primarily of the bis-complex, using
acetone. For purification it is necessary to perform repeated
crystallization’s. It is noteworthy that subsequent characteriza-
tion of 3 is hampered by the significant decrease of its solubility
once purified. Characterization of 1-6 was accomplished by
NMR spectrometry, elemental analyses, negative FAB-MS mass
spectrometry or X-ray diffraction.
Assignment of NMR data was based on homonuclear
decoupling, XHCORR, and COSY experiments. The NMR
spectra of 1-3 reflect a highly symmetrical orientation of the
three bridging thioether groups, that is, only one environment
is detected for R, â, or γ nuclei (for labeling see Scheme 1).
The NMR spectra of 4-6 resemble those of 1-3 but with an
apparent doubling of all the resonances. This is consistent with
one of the bridging thioethers having been replaced by a bridging
chlorine atom. This would, for example, create two sets of
magnetically equivalent R nuclei arising from the different
orientations that they can adopt with respect to the bridging
chloride. The apparent doubling is seen to decrease as one
moves to nuclei located farther and farther away from the bridge
where differing orientations are less pronounced. All 1H NMR
resonances are complicated by second-order effects. Chemical
The essential data for all crystals are summarized in Table 1.
Results and Discussion
Syntheses. Initially four thioether ring systems were stud-
ied: trimethylene sulfide, pms, 1,4-dithiane, and 1,4-thioxane.
The former two were an attempt to prepare a precursor, which
when ring-opened, created pendant arms of varying lengths. The
latter two were attempts to see whether incorporation of a
heteroatom into the thioether ring affected ring-opening and
consequently if metallo-donor groups could be incorporated via
the ring and not necessarily through the nucleophile. The
incorporation of a heteroatom was also seen to be a way of
decreasing the number of atoms which have no binding ability
and which therefore, would be expected to diminish stability
as well as potential electronic communication between a host
and guest. Placement of a heteroatom in a position para to the
sulfur atom was also seen as a way to facilitate the syntheses
of metalloligands possessing a crown ether type bracket.
Attempts to prepare the thietane complex, Cl3W(µ-S(CH2)3)3-
WCl3 (13), were unsuccessful. No reaction was observed at
room temperature even after 30 days. When higher temperatures
(10) Creagh, D. C.; Hubbell, J. H. International Tables for X-ray Crystal-
lography; Wilson, A. J. C., Ed.; Kluwer Academic Publishers: Boston,
1992; Vol. C, Table 4.2.4.3, pp 200-206.
(11) teXsan: Crystal Structure Analysis Package; Molecular Structure
Corporation: The Woodlands, TX, 1985 and 1992.
(12) Adams, R. D.; Falloon, S. B. Chem. ReV. 1995, 95, 2587-98.

Studies of Ditungsten(III) Complexes
Inorganic Chemistry, Vol. 37, No. 23, 1998 6027
Figure 2. ORTEP representation and labeling scheme for Cl3W(µ-
1,4-thioxane)3WCl3 (2).
Figure 1. ORTEP representation and labeling scheme for Cl3W(µ-
1,4-dithiane)3WCl3 (1). Hydrogen atoms omitted for clarity.
shifts and chemical shift differences suggest that in 2 and 5 it
is the sulfur and not the oxygen atom that is bridging.
Elemental analyses were not always consistent due to product
mixtures, decomposition or the incorporation of solvent. For
some, negative FAB-MS was useful for characterization. In
the cases where both negative FAB-MS and elemental analyses
were unclear, crystal structures were relied upon for definitive
results.
As a metalloligand precursor it is the ring-opening of the tris
complex which is of greatest interest for two reasons. An
anionic nucleophile would be expected to react with a neutral
species more favorably than with another anionic species, plus
the creation of a dianionic metalloligand might not be expected
to be as stable as a monoanionic one. When considering the
viability of using the newly prepared tris-ring thioether bridged
complexes in the syntheses of metalloligands, not only do these
desired complexes have to be able to be synthesized, but they
have to be synthesized in reasonable yields to be of any practical
value. The disappointingly low yields of 1 and 2 prompted
investigation into whether the bis complexes could be converted
to the tris thereby potentially increasing the yields of desired
species from 25 to 20% up to 50-100%, respectively.
Conversion of [Na][Cl3W(µ-L)2(µ-Cl)WCl3] to Cl3W(µ-L)3-
WCl3 was attempted by refluxing in the presence of excess L
(L ) 1,4-dithiane, 1,4-thioxane). The best percent conversions
observed were 50% and 20%, respectively, after reaction times
of 6 h, when toluene was used as a solvent.
Molecular Structures. The structures of 1, 2, 3, and 7, and
8 are shown in Figures 1-5, respectively. They strongly support
the validity of assignments made using NMR studies. Important
bond lengths and angles are given in Tables 3-5. They are
the first reported crystal structures of ditungsten(III) cyclic tris-
thioether-bridged complexes. The X-ray crystal structure of 5
proves unequivocally that 1,4-thioxane bridges two ditungsten-
(III) centers using only its sulfur atom. All the complexes adopt
the expected confacial bioctahedral framework. All possess
acute WSW bond angles from 61 to 63° and short W-W bonds
between 2.49 and 2.53 Å. Though the angles are similar to the
isostructural W2Cl93- ion, which is generally accepted to possess
a triple bond, the W-W bond lengths are some of the longest
observed for WIII-WIII complexes approaching those of WIII-
Figure 3. ORTEP representation and labeling scheme for Cl3W(µ-
pms)3WCl3 (3).
WIV.13 The thioether rings are oriented perpendicular to the
W-W bond and adopt staggered chair conformations with
respect to one another. Unlike their tht analogue, Cl3W(µ-tht)3-
WCl3 (12),14 the rings exhibited no disorder probably due to
the chair conformation being involved in the stabilization of
packing. All complexes were solvates. In the case of dithiane
or thioxane there was no significant interaction between the
solvent and the heteroatom in the ring. The S-C bond distances
for all are comparable to those in Cl3W(µ-SEt2)3WCl3 (14)1
Interestingly, for the dithiane complexes, there is no appreciable
difference between the µ-S-C bonds (1.79(2)-1.83(2) Å) and
the nonbridging S-C bonds (1.79(2)-1.86(2) Å), however, the
C-S-C angles are greater for the bridging S atoms (101.7-
(8)-104.1(8)°) as opposed to the nonbridging (96.8(9)-99.6-
(8)°). The authors have been able to find only one other
(13) Boorman, P. M.; Kraatz, H.-B. Coor. Chem. ReV. 1995, 143, 35-69.
(14) Boorman, P. M.; Richardson, J. F. University of Calgary, Calgary,
Alberta. Unpublished results.

6028 Inorganic Chemistry, Vol. 37, No. 23, 1998
Boorman et al.
Table 3. Selected Bond Lengths (Å) for Cl3W(µ-L)3WCl3 [L )
1,4-Dithiane (1), 1,4-Thioxane (2), pms (3)],
[PPh4][Cl3W(µ-1,4-dithiane)2(µ-Cl)WCl3] (7), and
[PPh4][Cl3W(µ-1,4-thioxane)2(µ-Cl)WCl3] (8)a
1
2
3
7
8
W(1)-W(2) 2.507(1) 2.529(1) 2.506(2) 2.481(2) 2.496(4)
W(1)-S(1) 2.413(4) 2.428(5) 2.418(6) 2.375(6) 2.38(2)
W(1)-S(2) 2.437(5) 2.419(5) 2.405(6) 2.406(6) 2.38(2)
W(1)-S(3) 2.420(5) 2.413(5) 2.414(6)
-
-
W(2)-S(1) 2.404(4) 2.415(6) 2.406(6) 2.378(7) 2.38(2)
W(2)-S(2) 2.431(5) 2.431(5) 2.401(6) 2.394(6) 2.39(2)
W(2)-S(3) 2.429(5) 2.425(5) 2.410(6)
-
-
S(1)-C(1)
S(1)-C(5)
S(2)-C(6)
S(2)-C(10) 1.85(2)
S(3)-C(11) 1.83(2)
S(3)-C(15) 1.82(2)
1.81(2)
1.81(2)
1.79(2)
1.84(2)
1.82(2)
1.83(2)
1.79(2)
1.81(2)
1.82(2)
1.79(2)
1.83(2)
1.83(2)
1.84(2)
1.80(3)
1.81(3)
1.80(3)
1.80(8)
1.87(3)
1.74(3)
1.80(3)
-
-
1.81(10)
1.84(8)
1.82(8)
-
-
X1-C(2)
X1-C(4)
X2-C(7)
X2-C(9)
X3-C(12)
X3-C(14)
1.79(2)
1.81(2)
1.83(2)
1.76(2)
1.81(2)
1.86(2)
1.44(3)
1.44(3)
1.39(3)
1.46(3)
1.48(3)
1.44(3)
1.50(3)
1.50(3)
1.52(3)
1.51(3)
1.51(3)
1.46(3)
1.81(2)
1.39(11)
1.78(2)
1.86(3)
1.76(3)
-
-
1.41(10)
1.46(10)
1.35(12)
-
-
Figure 4. ORTEP representation and labeling scheme for the anionic
portion of [PPh4][Cl3W(µ-1,4-dithiane)2(µ-Cl)WCl3] (7).
a X1 ) S(4) (1, 7); O(1) (2, 8); C(3) (3). X2 ) S(5) (1, 7); O(2) (2,
8); C(8) (3). X3 ) S(6) (1); O(3) (2); C(13) (3).
Table 4. Selected Bond Angles (deg) for Cl3W(µ-L)3WCl3 [L )
1,4-Dithiane (1), 1,4-Thioxane (2), pms (3)],
[PPh4][Cl3W(µ-1,4-dithiane)2(µ-Cl)WCl3] (7), and
[PPh4][Cl3W(µ-1,4-thioxane)2(µ-Cl)WCl3] (8)a
1
2
3
7
8
W(1)-S(1)-W(2)
W(1)-S(2)-W(2)
W(1)-S(3)-W(2)
62.7(1) 62.9(1) 62.6(2) 62.9(2) 63.3(5)
62.0(1) 62.8(1) 62.9(2) 62.2(2) 63.1(6)
62.3(1) 63.0(1) 62.6(1)
-
-
C(1)-S(1)-C(5)
102.9(8) 99(1) 102(1) 104(1) 101(4)
C(6)-S(2)-C(10) 104.1(8) 99(1) 102(1) 104(1) 103(4)
C(11)-S(3)-C(15) 101.7(8) 99(1) 100(1)
-
-
C(2)-X1-C(4)
C(7)-X2-C(9)
C(12)-X3-C(14)
98.0(8) 111(2) 112(2)
96.8(9) 112(2) 113(2)
99.6(8) 108(2) 112(2)
99(1) 115(7)
98(1) 110(7)
-
-
a X1 ) S(4) (1, 7); O(1) (2, 8); C(3) (3). X2 ) S(5) (1, 7); O(2) (2,
8); C(8) (3). X3 ) S(6) (1); O(3) (2); C(13) (3).
Figure 5. ORTEP representation and labeling scheme for the anionic
portion of [PPh4][Cl3W(µ-1,4-thioxane)2(µ-Cl)WCl3] (8). Hydrogen
atoms omitted for clarity.
via µ-S-C bond cleavage to produce 9-11. The reactions
producing 9 and 10 occurred at room temperature, that with 11
required refluxing conditions perhaps due to its insolubility once
purified. The NMR spectra of 9-11 show resonances for two
intact rings and the desired S(CH2)2E(CH2)2Sptol moiety (E )
S, O, CH2). Assignment was based on comparison of the
chemical shift changes observed for the Sptol ring-opened tht
analogue, [PPh4][Cl3W(µ-tht)2(µ-S(CH2)4Sptol)WCl3] (15),2
COSY, and XHCORR experiments.
Electrochemical Studies. The extreme insolubility of 3 once
purified and the difficulty in isolating 6 have resulted in
unsuccessful studies on these species. Cyclic voltammetric
studies of 1, 2, 4, 5, 7, and 8 were performed in CH2Cl2 by
employing [Bu4N][PF6] as the supporting electrolyte and a
graphite electrode with SCE reference electrode. 4 and 5
underwent cation exchange with the supporting electrolyte to
produce [Bu4N][Cl3W(µ-L)2(µ-Cl)WCl3] (L ) 1,4-dithiane (16),
1,4-thioxane (17)). All exhibit reversible waves representative
of a one-electron reduction. Within experimental error there is
no significant difference between the potentials exhibited for
the neutral heteroatom containing tris-thioethers, 1 and 2 (-0.62
V); however, they do differ significantly from the analogous
hydrocarbon thioethers, 12 and 14 (-0.72 V).1 The anionic
transition-metal dithiane bridged complex, where the sulfur
atoms of the dithiane are unoxidized, (CO)2CpMo(µ-S(CH2-
CH2)S)MoCp(CO)2.15 The dithiane ring in this structure also
lies perpendicular to the metal-metal bond and adopts a chair
conformation. Several structures of transition-metal thioxane
bridged complexes have been found in the literature.16a-c All
are late transition-metal complexes (Cu(I), Ag(I), and Pt(II))
and bridging occurs via either both the S and O atoms or only
the S atom.
Reactions with [PPh4][Sptol]. Once synthesized, nucleo-
philic attack with [PPh4][Sptol] was examined to see if 1-3
were suitable candidates for ring-opening. When reacted with
1 equiv of [PPh4][Sptol], all resulted in the desired ring-opening
(15) Bock, H.; Nuber, B.; Korswagen, R. P.; Ziegler, M. L., Bol. Soc. Quim.
Peru. 1988, 54, 211.
(16) (a) Buckholz, H. A.; Prakash, G. K. S.; Olah, G. A. Inorg. Chem.
1996, 35 (13), 4076. (b) Barnes, J. C.; Paton, J. D. Acta Crystallogr.,
Sect. B. 1982, 38, 3091. (c) Barnes, J. C.; Paton, J. D. Acta Crystallogr.,
C. (Cryst. Struct. Commun.) 1984, 40, 72. (d) Kukina, G. A.;
Sergienko, V. S.; Porai-Koshits, M. A.; Kukushkin, Yu. N. Koord.
Khim. 1986, 12, 1404.

Studies of Ditungsten(III) Complexes
Inorganic Chemistry, Vol. 37, No. 23, 1998 6029
Table 5. Comparison of Selected Structural Data for Cl3W(µ-L)3WCl3 [L ) 1,4-Dithiane (1), 1,4-Thioxane (2), pms (3)],
[PPh4][Cl3W(µ-1,4-dithiane)2(µ-Cl)WCl3] (7), and [PPh4][Cl3W(µ-1,4-thioxane)2(µ-Cl)WCl3] (8)
1
2
3
7
8
W-W (Å)
min-max W-S-W (deg)
min-max W-S (Å)
2.507(1)
62.0(1)-62.7(1)
2.404(4)-2.437(4)
2.529(1)
62.8(1)-63.0(1)
2.413(5)-2.431(5)
2.506(2)
62.6(1)-62.9(2)
2.401(6)-2.418(6)
2.481(2)
62.2(2)-62.9(2)
2.375(6)-2.406(6)
2.496(4)
63.1(6)-63.3(5)
2.38(2)-2.39(2)
bis-thioethers 7, 8, and 15 have a similar reduction wave
occurring at a more negative reduction potential (-1.17 to -1.23
V). The peak to peak separations observed were from 120 to
140 mV. The reversible reduction of the anionic bis-thioethers
suggests that similar behavior should be observed for the ring-
opened species (9-11).
a significant change in the tris:bis product distribution ratio.
Nucleophilic ring-opening was initiated in Cl3W(µ-L)3WCl3 but
could not be achieved for [Na][Cl3W(µ-L)2(µ-Cl)WCl3]. The
bis-thioether bridged complexes were converted to the tris- in
low yields. Electrochemical results for the anionic bis-
complexes suggest that ring-opened ditungsten (III) complexes
could behave as electron reservoirs.
Conclusions
Acknowledgment. The authors thank Dr. Scott Hinman of
the Department of Chemistry, University of Calgary, for the
use of his equipment and advice in obtaining the electrochemical
data and the University of Calgary and NSERC for financial
support.
The preparation of an analogue of Cl3W(µ-tht)3WCl3 (12)
using the four-membered thietane ring is not possible using our
thermally based synthetic procedure. The preparation of the
six-membered ring analogues Cl3W(µ-L)3WCl3 (L ) 1,4-
dithiane (1), 1,4-thioxane (2), pms (3)) has been achieved and
is accompanied by the synthesis of [Na][Cl3W(µ-L)2(µ-Cl)WCl3]
(L ) 1,4-dithiane (4), 1,4- thioxane (5), pms (6)). Overall
product yields were lowered when using a solid thioether.
Incorporation of heteroatoms into the thioether ring resulted in
Supporting Information Available: X-ray crystallographic files,
in CIF format, for complexes 1, 2, 3, 7, and 8 are available on the
Internet only. Access information is given on any current masthead
page.
IC971542T