Dimeric thiophosphorus complexes of sodium and zinc: Structural characterization of [(THF)2NaO(S)PPh2]2 and [Zn{S2P(OMe)C6H4OEt-p}2] 2

Article abstract of DOI:10.1016/j.ica.2007.06.026

Sodium P,P-diphenylphosphinothioate (2) was prepared by treatment of the free acid, Ph₂P(S)OH (1), with sodium bis(trimethylsilyl)amide and isolated as its THF adduct. The zinc phosphonodithioate complex [Zn{S₂P(OMe)C₆H

Full text of DOI:10.1016/j.ica.2007.06.026

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Inorganica Chimica Acta 361 (2008) 407–410
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Note
Dimeric thiophosphorus complexes of sodium and zinc:
Structural characterization of [(THF)2NaO(S)PPh2]2
and [Zn{S2P(OMe)C6H4OEt-p}2]2
a
a,
b,
b
a
Steffen Blaurock , Frank T. Edelmann *, Ionel Haiduc *, Gellert Mezei , Peter Poremba
a
Chemisches Institut, Otto-von-Guericke-Universita¨t Magdeburg, D-39106 Magdeburg, Germany
b
Facultatea de Chimie, Universitatea ‘‘Babes-Bolyai’’, RO-3400 Cluj-Napoca, Romania
Received 17 April 2007; received in revised form 14 June 2007; accepted 17 June 2007
Available online 30 June 2007
Dedicated to Professor Alfonso Castineiras on the occasion of his 65th birthday.
˜
Abstract
Sodium P,P-diphenylphosphinothioate (2) was prepared by treatment of the free acid, Ph2P(S)OH (1), with sodium bis(trimethylsi-
lyl)amide and isolated as its THF adduct. The zinc phosphonodithioate complex [Zn{S2P(OMe)C6H4OEt-p}2]2 (3) was obtained from
ZnCl2 and the readily accessible sodium salt of the ligand. According to X-ray diffraction studies, both compounds form dimers in
the solid state.
ꢀ 2007 Elsevier B.V. All rights reserved.
Keywords: Phosphinothioate ligands; Phosphonodithioate ligands; Sodium; Zinc; Crystal structures
1. Introduction
metal complexes have numerous industrial and agricultural
applications, e.g. as pesticides [5], additives for lubricants
[6], as floatation agents [7] and as CVD precursors for
the deposition of thin layers or nanocomposites [8]. Cas-
The P,P-diphenylphosphinothioate anion, [Ph2P(S)O]À,
is a highly versatile ligand in the main group and transition
metal coordination chemistry alike. Salts of this anion have
been utilized in the construction of supramolecular arrays
[1] as well as in the extraction of heavy metal ions [2]. Var-
ious complexes involving monodentate, bidentate, or
bridging coordination of the [Ph2P(S)O]À anion have been
reported [3,4]. Since very little is known about the struc-
tural chemistry of the corresponding alkali metal salts of
P,P-diphenyl-thiophosphinic acid (1), we investigated the
formation and structure of the sodium derivative.
tineiras et al. demonstrated that organotin dithiophosphi-
˜
nate derivatives exhibit considerable antiproliferation
activity toward certain leukemia cells [9]. We report here
the preparation and structural characterization of
[Zn{S2P(OMe)C6H4OEt-p}2]2 (3) which, like 2, also adopts
a dimeric structure in the solid state.
2. Experimental
The related phosphonodithioate anions [Ar(RO)PS2]À
(Ar = aryl, R = alkyl) have also attracted significant atten-
tion in recent years. The corresponding acids, salts, and
The compounds were prepared and handled under
nitrogen using standard Schlenk-line and dry-box tech-
niques. THF was dried over sodium/benzophenone and
freshly distilled under nitrogen prior to use. 1H NMR spec-
tra were recorded on a Bruker AM 250 instrument
(250 MHz, TMS). IR: Bio-RAD FTS 7. Elemental analyses
were performed using a Leco CHNS 923 apparatus.
*
Corresponding authors.
E-mail address: frank.edelmann@vst.uni-magdeburg.de (F.T. Edel-
mann).
0020-1693/$ - see front matter ꢀ 2007 Elsevier B.V. All rights reserved.
doi:10.1016/j.ica.2007.06.026

408
S. Blaurock et al. / Inorganica Chimica Acta 361 (2008) 407–410
Yellowish, prism-shaped single crystals of compound 2
were obtained by recrystallization from THF. Colorless
single crystals of 3 were grown from CH2Cl2 solution.
The crystals were mounted on a glass fiber in inert oil
and transferred to the cold gas stream of the diffractometer
(Stoe STADI-4). The structures were solved by direct
methods and subjected to full-matrix least-squares refine-
ment on F2 (program system SHELXL93) [10]. All non-
hydrogen atoms were refined anisotropically; hydrogen
atoms were included by using a riding model. The starting
materials 1 [11] and NaN(SiMe3)2 [12] were prepared
according to published procedures.
O
O
S
Ph2P
Na
OH
S
THF
+
2 NaN(SiMe3)2
2 Ph2P
O
O
S
- 2 HN(SiMe3)2
Na
O
Ph2P
1
O
2
Scheme 1.
2.1. Sodium-P,P-diphenylphosphinothioate,
[(THF)2NaO(S)PPh2]2 (2)
refluxing THF. A simple work-up procedure afforded the
analytically pure product in 94% yield.
Compound 2 was isolated as a nearly colorless (large
crystals are yellowish), moderately moisture-sensitive solid,
which dissolves freely in THF or acetonitrile, but is virtu-
ally insoluble in diethylether, toluene, and hexane. The
1H NMR spectrum showed only signals for the phenyl
groups and coordinated THF. An elemental analysis con-
firmed the presence of two THF ligands at sodium.
Monodentate coordination of the Ph2P(S)OÀ anion
through oxygen could be deduced from the appearance
of a strong band at 894 cmÀ1 (P–O single bond) and a
strong band at 631 cmÀ1 (P@S double bond) in the IR
spectrum. Slightly yellowish X-ray quality crystals of 2
were grown by slow cooling of a saturated solution in
THF to À20 ꢁC. Crystal data are given in Table 1. The
compound crystallizes as a centrosymmetric dimer. Fig. 1
shows an ORTEP drawing of the molecular structure of
2 as well as selected interatomic distances and angles. With
a O(1a)–Na(1)–O(1) angle of 88.2ꢁ, the central four-mem-
bered Na2O2 ring is almost rectangular. Through the over-
all chair-like conformation of the central ring systems,
repulsion between phenyl groups is minimized. The five-
coordinate Na ion adopts a distorted tetragonal-pyramidal
coordination geometry with O(1), O(1a), O(31), and S(1)
forming the base of the pyramid. The THF oxygen atom
O(41) is in the apical position. The smallest angle at sodium
is O(1)–Na(1)–S(1) with 65.7ꢁ, which indicates only a weak
interaction between sodium and sulfur. The bond lengths
To a solution of 0.548 g (3.00 mmol) NaN(SiMe3)2 in
50 ml THF was added 0.700 g (3.00 mmol) of neat
Ph2P(S)OH (1) and the stirred mixture was heated to reflux
until the acid had completely dissolved (ca. 5 min).
Removal of all volatile components and drying of the res-
idue at 70 ꢁC under vacuum afforded 1.124 g (94%) of a
white solid. Mp 124–126 ꢁC (dec.). Anal. Calc. for
C40H52Na2O6P2S2 (800.86): C, 60.0; H, 6.5. Found: C,
59.0; H, 6.1%. IR (Nujol): 3045 s, 1983 m, 1903 m, 1834
m, 1683 m, 1587 m, 1308 s, 1294 s, 1260 s, 1179 s, 1074
vs, 1027 vs, 997 s, 894 s, 854 w, 758 s, 747 vs, 714 vs, 693
1
vs, 631 vs, 613 vs, 531 vs, 526 vs, 511 vs, 419 s cmÀ1. H
NMR (CD3CN): d 7.25– 7.37 (m, 20H, C6H5), 3.63 (m,
16H, THF–OCH2), 1.79 (m, 16H, THF–CH2) ppm. 31P
NMR (CD3CN): d 55.3 ppm.
2.2. Zinc(II)-(O-methyl)-p-ethoxyphenyIphosphono-
dithioate, [Zn{S2P(OMe)C6H4OEt-p}2]2 (3)
To a solution of 0.530 g (2.00 mmol) of NH4[S2P(OMe)-
C6H4OEt-p] in 60 ml methanol was added 0.136 g
(1.00 mmol) anhydrous ZnCl2 and the mixture was stirred
at room temperature for 24 h. All volatile components were
removed under vacuum and the residue was extracted with
dichloromethane (50 ml). Filtration through Celite and
evaporation of the filtrate to dryness afforded 0.403 g
(72%) of a white solid. Mp 170–175 ꢁC (dec.). Anal. Calc.
for C36H48O8P4S8Zn2 (1119.95): C, 38.6; H, 4.3. Found:
C, 38.8; H, 4.3%. IR (Nujol): 3055 s, 1898 m, 1830 m,
1680 m, 1578 m, 1311 m, 1277 s, 1176 m, 1066 vs, 1023
˚
are in agreement with this assumption. With 3.003 A, the
˚
Na(1)–S(1) bond is 0.013 A longer than the sum of the
˚
covalent radii (2.89 A) and should thus be regarded as a
secondary NaÁ Á ÁS bond. Similar self-assembly under for-
mation of a dimer has been reported for the related species
[(THF)KSe(NSiMe3)PPh2]2 [13].
1
vs, 1001 vs, 653 m, 541 s cmÀ1. H NMR (CD2Cl2): d
7.90 (dd, 8H, o-C6H4), 6.95 (dd, 8H, m-C6H4), 3.88 (q,
3
8H, CH2), 3.60 (d, 12H, JPH = 15.0 Hz, OMe), 1.35 (t,
The zinc phosphonodithioate complex [Zn{S2P(OMe)-
C6H4OEt-p}2]2 (3) was prepared in 72% yield by treatment
of the recently reported ammonium salt NH4[S2P(OMe)-
C6H4OEt-p] [14] in methanol followed by extraction with
dichloromethane. Compound 3 is a structural isomer of
the zinc complex [Zn{S2P(OEt)C6H4OMe-p}2]2 3a which
was reported by Woollins and co-workers (Scheme 2) [15].
With the exception of the OMe and OEt resonances in the
1H NMR spectrum the analytical and spectroscopic data of
12H, Me) ppm. 31P NMR (CD2Cl2): d 100.1 ppm.
3. Results and discussion
The compound [(THF)2NaO(S)PPh2]2 (2) was prepared
as shown in Scheme 1 by treatment of the free acid 1 with
an equimolar amount of sodium bis(trimethylsilyl)amide in

S. Blaurock et al. / Inorganica Chimica Acta 361 (2008) 407–410
409
Table 1
Crystal data and structure refinement for 2 and 3
Empirical formula
Formula weight
Temperature (K)
C40H52Na2O6P2S2 (2)
800.86
143(2)
C36H48O8P4S8Zn2 (3)
1119.95
173(2)
˚
Wavelength (A)
0.71073
0.71073
ꢀ
Crystal system, space group
Unit cell dimensions
triclinic, P1
monoclinic
˚
a (A)
9.828(7)
10.445(8)
11.161(7)
103.67(7)
105.12(3)
96.28(9)
1056.7(13)
2, 1.258
12.200(3)
18.803(3)
10.4665(15)
90
98.037(11)
90
2377.4(7)
2, 1.564
1.541
1152
˚
b (A)
˚
c (A)
a (ꢁ)
b (ꢁ)
c (ꢁ)
Volume (A )
Z, Dcalc (Mg/m3)
Absorption coefficient (mmÀ1
F(000)
3
˚
)
0.265
424
Crystal size (mm)
h Range for data collection (ꢁ)
0.80 · 0.70 ·
3.89–22.59
0.40 · 0.40 · 0.20
1.69–28.33
À16 6 h 6 16,
À25 6 k 6 22,
À11 6 l 6 13
15806/5861 [Rint = 0.0172]
SADABS
Limiting indices
À10 6 h 6 10,
À11 6 k 6 11,
À12 6 l 6 12
4173/2765 [Rint = 0.1050]
w-scan
Reflections collected/unique
Absorption correction
Maximum/minimum transmission
Refinement method
Data/restraints/parameters
Goodness-of-fit on F2
0.8361 and 0.8158
full-matrix least-squares on F2
2765/0/235
1.00 and 0.84
full-matrix least-squares on F2
5857/0/266
1.062
1.036
Final R indices [I > 2r(I)]
R indices (all data)
Largest difference in peak and hole (e AÀ3
R1 = 0.0755, wR2 = 0.1957
R1 = 0.0785, wR2 = 0.2010
0.789 and À0.626
R1 = 0.0217, wR2 = 0.0545
R1 = 0.0263, wR2 = 0.0573
0.666 and À0.297
)
OEt
MeO
S
P
P
EtO
OMe
S
S
S
P
Zn
Zn
P
S
S
S
S
MeO
OEt
OMe
EtO
3
OMe
S
EtO
P
MeO
OEt
S
S
S
Fig. 1. Molecular structure of [(THF)2NaO(S)PPh2]2 (2). Selected bond
lengths (A) and angles (ꢁ) (Na(1)#1 denotes the symmetry-related sodium
S
P
˚
Zn
Zn
P
S
S
ion): S(1)–P(1) 1.977(2), S(1)–Na(1) 3.003(3), O(1)–P(1) 1.509(3), O(1)–
Na(1)#1 2.250(3), O(1)–Na(1) 2.351(3), Na(1)–O(31) 2.287(4), Na(1)–
O(41) 2.300(4), P(1)–C(11) 1.822(4), P(1)–C(21) 1.824(4), P(1)–S(1)–Na(1)
73.44(7), P(1)–O(1)–Na(1)#1 148.46(16), P(1)–O(1)–Na(1) 104.18(14),
Na(1)#1–O(1)–Na(1) 91.83(12), O(1)#1–Na(1)–O(31) 98.17(14), O(1)#1–
Na(1)–O(1) 88.17(12), O(1)#1–Na(1)–S(1) 136.73(10), O(1)–Na(1)–S(1)
65.71(8), O(1)#1–Na(1)–P(1) 113.08(11), O(1)–P(1)–S(1) 115.29(13).
S
EtO
OMe
P
OMe
MeO
3a
Scheme 2.
3 are very similar to those of 3a. Colorless single crystals of 3
were obtained by slow evaporation of a saturated solution in
dichloromethane. The X-ray crystal structure determination
revealed again a dimeric solid state structure (Table 1,
Fig. 2). Two phosphonodithioate ligands are bidentate
and the other two act as bridges between the zinc atoms.

410
S. Blaurock et al. / Inorganica Chimica Acta 361 (2008) 407–410
˚
Fig. 2. Molecular structure of [Zn{S2P(OMe)C6H4OEt-p}2]2 (3). Selected bond lengths (A) and angles (ꢁ): Zn–S(1) 2.3432(5), Zn–S(2) 2.4178(5), Zn–S(3)
2.3676(5), Zn–P(1) 2.8663(5), S(1)–P(1) 2.0125(6), S(2)–P(1) 1.9984(6), S(1)–Zn–S(2) 86.61(2), S(3)–Zn–S(2) 102.18(2), S(2)–P(1)–S(1) 109.03(2), S(3)–
P(2)–S(4) 117.27(2).
(c) M.J. Begley, D.B. Sowerby, D.M. Wesolek, C. Silvestru, I.
Haiduc, J. Organomet. Chem. 316 (1986) 281;
As expected, the overall structural features are very similar
to those in 3a. Closely related dimeric molecular structures
(d) K.C.K. Swamy, C.G. Schmid, R.O. Day, R.R. Holmes, J. Am.
have also been reported for [Zn{S2P- (OBu)2}2]2 [16] and
Chem. Soc. 110 (1988) 7067.
[Zn{S2PFcOMe}2]2 (Fc = ferrocenyl) [17].
[4] (a) K.-M. Muhlsiepen, R. Mattes, Z. Anorg. Allg. Chem. 506 (1983)
¨
115;
(b) K.-M. Mu¨hlsiepen, R. Mattes, Z. Anorg. Allg. Chem. 506 (1983)
125.
4. Supplementary material
[5] N.K. Roy, Pesticides A 1989–90 (1990) 13.
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[7] M. Fuller, M. Kasrai, J.S. Sheasby, G.M. Bancroft, K. Fyfe, K.H.
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[8] M. Gianini, W.R. Caseri, V. Gramlich, U.W. Suter, Inorg. Chem. 299
(2000) 199.
CCDC 635384 and 646015 contain the supplementary
crystallographic data for 2 and 3. These data can be
obtained free of charge via http://www.ccdc.cam.ac.uk/
conts/retrieving.html, or from the Cambridge Crystallo-
graphic Data Centre, 12 Union Road, Cambridge CB2
1EZ, UK; fax: (+44) 1223-336-033; or e-mail: deposit@
ccdc.cam.ac.uk.
´
[9] J.S. Casas, A. Castineiras, M.C. Rodriguez-Arguelles, A. Sanchez, J.
˜
¨
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P. Dall’Aglio, R. Albertini, J. Inorg. Biochem. 76 (1999) 277.
[10] G.M. Sheldrick, SHELXL93, Program for Crystal Structure Refine-
ment, University of Go¨ttingen, Germany, 1993.
[11] W.A. Higgins, P.W. Vogel, W.G. Craid, J. Am. Chem. Soc. 77 (1955)
1864.
[12] U. Wannagat, H. Niederprum, Chem. Ber. 94 (1961) 1540.
¨
[13] T. Chivers, M. Parvez, M.A. Seay, Inorg. Chem. 33 (1994)
2147.
Acknowledgments
The authors thank the Fonds der Chemischen Industrie
and the Otto-von-Guericke-Universita¨t Magdeburg for
financial support of this work.
[14] I. Haiduc, G. Mezei, R. Micu-Semeniuc, F.T. Edelmann, A. Fischer,
Z. Anorg. Allg. Chem. 632 (2006) 295.
[15] I.P. Gray, A.M.Z. Slawin, J.D. Woollins, Dalton Trans. (2004)
2477.
[16] S. Menzer, J.R. Phillips, A.M.Z. Slawin, D.J. Williams, J.D.
Woollins, Dalton Trans. (2000) 3269.
[17] I.P. Gray, H.L. Milton, A.M.Z. Slawin, J.D. Woollins, Dalton Trans.
(2003) 3450.
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