Disilyl dithiophosphonates in the synthesis of open chain and cyclic organothiophosphorus compounds

Article abstract of DOI:10.1002/hc.20009

O-(Trimethylsiloxy)alkyl S-trimethylsilyl aryldithiophosphonates 7a-d were obtained by the reaction of 2,4-diaryl-1,3,2,4-dithiadiphosphetane-2,4- disulfides 5a,b with disilyl derivatives of glycols 6a,c and salicyl alcohol 6b. The reactions of mixed O,S-

Full text of DOI:10.1002/hc.20009

Heteroatom Chemistry
Volume 15, Number 3, 2004
Disilyl Dithiophosphonates in the Synthesis of
Open Chain and Cyclic Organothiophosphorus
Compounds
Il’yas S. Nizamov,1,2 Gul’nur G. Sergeenko,2 Il’nar D. Nizamov,1
Yan E. Popovich,2 Ravil N. Khaibullin,2 Lyubov A. Al’metkina,3
Boris E. Abalonin,1 Elvira S. Batyeva,2 Dmitry B. Krivolapov,2
and Igor A. Litvinov2
1Kazan State Pedagogical University, Mezhlauk Str. 1, 420021 Kazan, Russia
2A. E. Arbuzov Institute of Organic and Physical Chemistry, Russian Academy of Sciences,
Arbuzov Str. 8, 420088 Kazan, Russia
3Orenburg State University, Prospekt Pobedy, 13, 460352 Orenburg, Russia
Received 9 December 2003
INTRODUCTION
ABSTRACT: O-(Trimethylsiloxy)alkyl S-trimethyl-
silyl aryldithiophosphonates 7a–d were obtained by
the reaction of 2,4-diaryl-1,3,2,4-dithiadiphosphetane-
2,4-disulfides 5a,b with disilyl derivatives of glycols
6a,c and salicyl alcohol 6b. The reactions of mixed
O,S-bis(trimethylsilyl) 2,4-di(3,5-di-tert-butyl-4-hydr-
oxyphenyl)dithiophosphonate 1 and S-silyl aryldithio-
phosphonates 7a,b with S,S-diethyldithiodiphenylge-
rmane 2, dichlorodiphenylgermane 8a, and dichloro-
diphenylstannane 8b were studied. The structure of
hexaphenyl-2,4,6,1,3,5-trithiatrigerminane 11 was
The chemistry of derivatives of tetracoordinated
phosphorus thioacids containing a few trimethylsilyl
groups have recently been developed [1–7]. Com-
mon methods of synthesizing tris(trimethylsilyl)
tetrathiophosphate and bis(trimethylsilyl) phenyltri-
thiophosphonate containing three or two S SiMe3
fragments were usually based on the reactions of bis
(trimethylsilyl)sulfide with tetraphosphorus decasul-
fide and 2,4-diphenyl-1,3,2,4-dithiadiphosphetane-
2,4-disulfide or addition of sulfur to disilyl or
trisilyl phosphines [1,2]. In this article, a method is
presented for synthesizing new O-trimethylsiloxyor-
ganyl S-trimethylsilyl aryldithiophosphonates on
the basis of the reactions of 2,4-diaryl-1,3,2,4-
ꢀ
C
established by X-ray single crystal diffraction.
2004
Wiley Periodicals, Inc. Heteroatom Chem 15:225–
232, 2004; Published online in Wiley InterScience
(www.interscience.wiley.com). DOI 10.1002/hc.20009
dithiadiphosphetane-2,4-disulfides
with
disilyl
derivatives of diols. The reactions of O,S-disilyl
aryldithiophosphonates and O-trimethylsiloxyor-
ganyl S-trimethylsilyl aryldithiophosphonates with
S,S-diethyldithio- and dichlorodiphenylgermanes,
and dichlorodiphenylstannane were also studied.
The formation and molecular and crystal structure
of six-membered 1,3,5-hexaphenyl-2,4,6,1,3,5-trithi-
atrigerminane are described.
Correspondence to: Il’yas S. Nizamov, A. E. Arbuzov Institute of
Organic and Physical Chemistry, Russian Academy of Sciences,
Arbuzov Str. 8, 420088 Russia.
2004 Wiley Periodicals, Inc.
c
ꢀ
225

226 Nizamov et al.
RESULTS AND DISCUSSION
about the formation of O-trimethylsilyl S-(ethyl-
thio)diphenylgermyl 3,5-di-tert-butyl-4-hydroxyphe-
nyldithiophosphonate 3 with the elimination of
trimethylsilyl(ethylthio)silane 4 (Reaction 1, see
Tables 1–5).
The chemical properties of bis(trimethylsilyl) or-
ganyltrithiophosphonates were rather studied. Thus,
the substitution reactions of bis(trimethylsilyl) or-
ganyltrithiophosphonates with methanol, water,
halogens, sulfur chlorides, and dimethyl sulfoxide
have been reported to result in trithiophosphonic
acids and cyclic anhydrides of perthiophosphonic
acids [4–6]. Taking into account the facile occur-
rence of substitution reactions [4–7], we have tried
to extent similar reactions on dithiophosphonates
containing both S SiMe3 and O SiMe3 fragments.
We have recently developed convenient methods
for the synthesis of mixed O,S-bis(trimethylsilyl)
esters of aryldithiophosphonic acids by of the
reaction of 2,4-diaryl-1,3,2,4-dithiadiphosphetane-
2,4-disulfides with disilylated acetamide [3]. O,S-
Disilyl aryldithiophosphonates contain both reac-
tive S Si and O Si bonds and two readily leav-
ing trimethylsilyl groups. The formation of linear
or cyclic products could be expected by the use of
O,S-disilyl aryldithiophosphonates in the reactions
with halides or dialkyldithio derivatives of germa-
nium and tin containing the Ge S, Ge Cl, or Sn Cl
bonds.
(1)
Product 3 was purified by column chromatogra-
phy. Ethylthiosilane 4 was removed from the reac-
tion mixtures by evaporation at reduced pressure. It
was purified by a subsequent distillation. Substitu-
tion of only one of the silicon atoms of 1 was con-
firmed by 31P and 1H NMR spectra of 3 (Tables 2 and
4). The 31P NMR spectrum of S-germyl dithiophos-
phonate 3 in benzene solution (Table 2) shows a sin-
glet at ꢀ = 83.9. This resonance is shifted toward low
field in comparison with that 1 (δ = 75.6 [3]). The 1H
NMR spectrum of 3 (Table 4) reveals the characteris-
tic resonances of a O-trimethylsiloxy group attached
to the phosphorus atom. The band of strong intensity
in the region of ꢁ 1260 cm−1 in the IR spectrum of
3 (Table 3) is due to the CH3(Si) symmetrical defor-
mation vibrations. Two bands in the region of ꢁ 465
and 408 cm−1 are assigned to the GePh2 and S Ge
The reaction of O,S-bis(trimethylsilyl) 2,4-di(3,
5-di-tert-butyl-4-hydroxyphenyl)dithiophosphonate
1 with S,S-diethyldithiodiphenylgermane 2 in anhy-
drous benzene at 20◦C for 4 h has been found to bring
TABLE 1 Experimental Data and Yields of the Products
Reaction Conditions
Temp. (◦C)
Time (h)
Initial Compoundsa
1.0 (2.2);
Product Yieldb
1
2 0.8 (2.2)
20
4
3
0.9 (60)c/0.6 (40)d; 4 0.2 (67)c
5 ml C6H6
60–70
20
20
20
20
5a 81.2 (209.9);
5b 15.0 (25.0);
5a 3.5 (8.7);
5a 15.6 (38.6);
7a 3.3 (7.6);
6a 94.3 (402.1)
6a 11.7 (49.9)
6b 4.6 (17.2)
6c 19.2 (77.3)
8a 2.3 (7.7)
8
20
15
14
4
7a 132.7 (76)c/98.0 (56)e
7b 12.6 (47)c/2.7 (10)e
7c 5.1 (65)c/2.5 (32)e
7d 18.7 (53)c/11.1 (32)e
9a 3.6 (65)c/1.4 (25)e
3 ml C6H6
50
5 ml C6H6
20
10 ml C6H6
125
7b 3.6 (6.7);
7a 5.5 (12.6);
7b 3.0 (5.6);
8a 2.0 (6.7)
8b 4.3 (12.5)
2 2.0 (5.7)
2
4
3
9b 3.2 (78)c/1.3 (32)d; 10 0.9 (60) f
9c 7.2 (85)c/1.3 (18)d; 10 0.8 (57) f
9b 2.2 (63)g; 11 0.5g; 4 0.8 (53) f
aQuantity in gram (mmol).
bProduct yield in gram (percent).
cYield of crude product.
dYield of product isolated by column chromatography.
eYield of product isolated by a falling-film distillation.
f Yield of product isolated by a distillation.
gYield of crystalline product.

Disilyl Dithiophosphonates in the Synthesis of Open Chain and Cyclic Organothiophosphorus Compounds 227
TABLE 2 Physical, Analytical, and 31P NMR Data of the Products Obtained
Found/Calc. %
P
Molecular Formula
(Mol. mass)
b.p. (◦C)a
n2D0
E
S
31P NMR, δ (C6 H6)
3b
C31H45GeO2PS3Si
(676.9)
C17H33O3PS2Si2
(436.2)
10.66Ge
10.72Ge
12.48Si
12.83Si
4.26
4.58
6.80
7.10
14.55
14.17
83.9
7a
100 (0.04)c
1.5183
85.7 (6)d
85.5 (10)d
84.8 (19)d
84.4 (12)d
87.9 (13)d
86.8 (11)d
86.5 (58)d
86.1 (100)d
85.4
7b
150 (0.03)c
1.5280
C24H47O3PS2Si2
(534.3)
10.35Si
10.47Si
5.59
5.80
7c
7d
9a
100–105 (0.04)c
95 (0.06)c
C20H31O2PS2Si2
(454.2)
C18H35O3PS3Si2
(450.2)
C23H25GeO3PS2
(516.8)
12.72Si
12.32Si
12.36Si
12.43Si
14.47Ge
14.05Ge
7.01
6.82
6.74
6.88
5.82
5.99
1.5320
1.5958
14.19
14.20
85.6
170 (0.05)c
100.8 (2)d
99.8 (100)d
99.3 (4)d
9b
9c
70e
C30H39GeO3PS2
(614.9)
C23H25O3PS2Sn
(562.8)
11.74Ge
11.84Ge
20.92Sn
21.09Sn
5.01
5.04
5.17
5.50
103.3 (1)d
101.9 (7)d
100.6 (13)d
99.8 (18)d
130(0.05)
1.6244
aTemperature of thermal element of a falling-film distillation.
b Rf 0.94 (C6H6)
c Values in parentheses in this column indicate pressure (mm Hg).
d The mixture of isomers, values in parentheses in this column indicate the integral intensity ratio (percentage).
e m.p. (◦C).
TABLE 3 IR Data of the Products Obtained
ν, cm−1
3
3636 ν (O H); 3075, 3050 ν ( C H, Ar); 2966, 2930, 2875 ν (CH3 as, s), ν [CH3(Si) s]; 1585, 1485 ν
(C C, Ar); 1435 δ (CH3 as); 1260 δ [CH3(Si) s]; 1100 ν (P Ar); 860 ν [P O(C)]; 695 ν (P S); 652 ν
(C S); 615 ν (P S); 465 ν (GePh2); 408 ν (S Ge).
7a
7b
7c
7d
3075 ν ( C H, Ar); 2980, 2960, 2900, 2842 ν (CH3 as, s), ν (CH), ν [CH3(Si) s); 1593, 1500
ν (C C, Ar); 1255 δ [CH3(Si) s]; 1036 ν [(P)O C)]; 880 ρ [CH3(Si)], 848 ν [P O(C)]; 680
ν (P S); 622, 539, 515 ν (P S, S-Si).
3635 ν (O H); 3010 ν ( C H, Ar); 2965, 2910, 2885 ν (CH3 as, s), ν (CH), ν [CH3(Si) s); 1588,
1490 ν (C C, Ar); 1435 δ (CH3 as); 1370 δ (CH3 s); 1258 δ [CH3(Si) s]; 1040 ν [(P)O C]; 850 ρ
[CH3(Si)], ν [P O(C)]; 665 ν (P S); 515 ν (P S, S Si).
3085, 3012 ν ( C H, Ar); 2967, 2910, 2844 ν (CH3 as, s; CH2 as, s), ν [CH3(Si) s); 1600, 1505, 1460 ν
(C C, Ar); 1270, 1260 δ [CH3(Si) s]; 1035, 1020, 1010 ν [(P)O C], ν [O C(Ar)]; 855 ρ [CH3(Si)],
ν [P O(C)]; 710 ν (P S); 625, 580, 535 ν (P S, S Si).
3075, 3012 ν ( CH, Ar); 2965, 2910, 2840 ν [CH3(Si) s]; ν (CH3 as, s; CH2 as, s); 1594, 1504 ν (C C, Ar);
1463 δ (CH3s); 1260 δ [CH3(Si) s]; 1034 ν [(P)O C)]; 860 ρ [CH3(Si)]; ν [P O(C)]; 688 ν (P S);
541 ν (P S, S Si).
9a
3073, 3052 ν ( C H, Ar); 2980, 2932, 2910, 2840 ν (CH3 as, s; CH); 1593, 1500 ν (C C, Ar); 1030
ν [(P)O C]; 945 ν (OC C); 695 ν (P S); 563, 530, 520 ν (P S); 465 ν (GePh2 as); 410 ν (S Ge).
3618 ν (O H); 3080, 3058 ν ( C H, Ar); 2965. 2912, 2878 ν (CH3 as, s, CH); 1588, 1488, 1455 ν (C C, Ar);
1432 δ (CH3 as); 1030 ν [(P)O C)]; 950 ν (C CO); 865 ν [P O(C)]; 695 ν (P S); 570, 510 ν (P S); 463 ν
(GePh2 as); 412 ν (S Ge).
9ba
9c
3080, 3050 ν ( C H, Ar); 2980, 2933, 2910, 2845 ν (CH3 as, s; CH); 1594, 1500 ν (C C, Ar); 1030 cp
ν [(P)O C]; 945 ν (OC C); 678 ν (P S); 570, 535 ν (P S); 450 ν (GePh2 as).
aIn vaseline oil.

228 Nizamov et al.
valence vibrations, respectively. The electron impact
mass spectrum of 3 (Table 5) exibits the mass peak
m/e 677 that may be attributed to its molecular ion
[M]+.. The O Si bond remained attached to the phos-
phorus atom of 3.
rified by use of a falling-film distillation.
Thus, the reaction of mixed O,S-disilyl dithio-
phosphonates 1 with diethyldithiogermane 2 at
room temperature proceeds via the rupture of the
most reactive S Si bond and only one of the S Ge
linkages. The reaction stops on the stage of the open
chain S-germyldithiophosphonate 3 which does not
undergo a further transformation to a cyclic com-
pound at room temperature. Nevertheless, 3 seems
to be a model of some precursor of the ring-closure
reaction.
To obtain the heterocycles we decided to use
more reactive bifunctional compounds. For this pur-
pose, disilyl dithiophosphonates 7 were obtained.
Disilyl derivatives of glycols 6a,c and of salicyl al-
cohol 6b were found to react with 2,4-diaryl-1,3,2,4-
dithiadiphosphetane-2,4-disulfides 5a,b at 20–70◦C
for 8–20 h with the rupture of only one O Si bond
and the formation of O-(trimethylsiloxy)alkyl S-
trimethylsilyl aryldithiophosphonates 7a–d (Reac-
tion 2, Tables 1–5). All compounds 7a–d were pu-
(2)
As 2,3-bis(trimethoxy)butane 6a exists in a mix-
ture D,L- and meso-forms, the disilyl dithiophospho-
nates 7a and 7b occur as a mixture of isomers too.
Compounds 7a and 7b contain three asymmetrical
atoms. The 31P NMR spectrum of 7a (Table 2) in
benzene solution reveals four singlets at δ = 85.7,
85.5, 84.8, and 84.4 in the integral intensity ratio
6:10:19:12. Four 31P resonances of 7b (δ = 86.1–87.9)
appear in practically the same region as that of 7a
(Table 2). In contrast of this, the 31P NMR spectra of
7c and 7d show singlets at δ = 85.4 and 85.6, respec-
1
tively. The H NMR spectrum of 7c in CCl4 solution
(Table 4) reveals two singlets at δ = 0.33 and 0.45 as
TABLE 4 1H NMR Data of the Products Obtained
δ, J [Hz]
3a
0.33 (s, 9H, (CH3)3SiOP); 1.31 (t, 3H, CH3CH2S, 3 JHH7.2); 1.56 (s, 18H, (CH3)3C); 2.97 (q, 2H,
CH3CH2S, 3 JHH7.2); 6.98–7.98 (m, 10H, (C6H5)2Ge; 2H, 2,6-H2C6).
7aa,b
0.13–0.25 (m, 9H, (CH3)3SiSP; 9H, (CH3)3SiOC); 0.87–1.64 (m, 3H, CH3CHOP + 3H, CH3CHOSi,
3JHH 6.0); 3.35–4.26 (m, 2H, CH); 3.77–3.92 (m, 3H, CH3OC6H4); 6.72–7.03 (m, 2H, 3,5-H2C6CH2,
3JHH 9.0, 4 JPH 3.0); 7.92–8.06 (m, 2H, 2,6-H2C6H2, 3JHH 9.0, 3 JPH 15.0).
7bb,c
0.03–0.20 (m, 9H, (CH3)3SiSP); 0.28–0.42g(m, 9H, (CH3)3SiOC); 1.05–1.20 (m, 6H, OCHCH3 CHCH3O);
1.30, 1.37, 1.39, 1.45 (four s, 18H, (CH3)3C); 3.48–3.65 (m, 2H, OCHCHO); 7.81–7.83 (m, 2H, 2,6-H2C6,
3JPH15.0).
7ca
7da
0.33 (s, 9H, (CH3)3SiSP); 0.45 (s, 9H, (CH3)3SiOC); 3.82 (s, 3H, CH3OC6H4); 5.26 (d, 2H, CH2OP,
3JHH 9.0); 6.67–7.61 (m, 4H, C6H4CH2; 2H, 3,5-H2C6H2; 2H, 2,6-H2C6H2).
0.11 (s, 9H, (CH3)3SiSP); 0.30 (s, 9H, (CH3)3SiOC); 1.11 (s, 6H, (CH3)2C); 3.67 (s, 2H, CH2OSi); 3.82
(s, 3H, 4-CH3OC6H4); 4.07 (d, 2H, CH2OP, 3 JPH6.0); 6.93 (d. d, 2H, 3,5-H2C6H2, 3 JHH9.0,4 JPH3.5);
7.76 (d. d, 2H, 2,6-H2C6H2, 3 JHH9.0,4 JPH14.0).
9ab,d
0.76–1.05 (m, 6H, OCHCH3CHCH3O); 3.23 (broad s, 3H, CH3OC6H4); 3.69 (m, 1H, CH3CHOGe);
3.99–4.10 (m, 1H, CH3CHOP); 6.77 (m, 2H, 3,5-H2C6H2, 3JHH 9.0, 4 JPH 3.0); 6.96–7.15 and 7.54–7.63
(two m, 10H, Ge(C6H5)2); 7.86 (m, 2H, 2,6-H2C6H2, 3JHH 9.0, 3 JPH 14.5).
9bb,c
9cb,d
1.17–1.74 (m, 24H, CH3); δ1 4.21 (m, 1H, GeOCHCH); δ2 4.47 (m, 1H, POCHCH); δ1 4.76 (m, 1H,
ꢁ
GeOCHCH); δ2 5.00 (m, 1H, POCHCH); 5.81 (M, 1H, OH); 7.46–7.94 (m, 12H, H arom.).
0.83–1.11 (m, 6H, OCHCH3CHCH3O); 3.21 (broad s, 3H, CH3OC6H4); 3.64–3.76 (m, 1H, CH3CHOSn);
3.21–3.24 (m, 1H, CH3CHOP); 7.12–7.15 and 7.75 (two m, 10H, Sn(C6H5)2); 6.60–6.60
(m, 2H, 3,5-H2C6H2); 7.88 (m, 2H, 2,6-H2C6H2, 3JHH 9.0).
aIn CCl4.
bThe mixture of isomers.
cIn CDCl3.
dIn C6D6.

Disilyl Dithiophosphonates in the Synthesis of Open Chain and Cyclic Organothiophosphorus Compounds 229
mixtures of isomers. The 31P NMR spectrum of 9a
in benzene solution (Table 2) shows three main sin-
glets at δ = 100.8, 99.8, and 99.3 in the integral inten-
sity ratio 2:100:4. A similar picture was observed in
the case of 9b (see Table 2). Two singlets (δ = 100.6
and 99.8 in the integral intensity ratio 13:18) were
a result of the methyl protons of two SiMe3 groups
at the oxygen and the sulfur atoms, respectively, in
the integral intensity ratio 1:1. It is noteworthy that
a doublet at δ = 5.25 (3 JPH = 9.0) is attributed to the
protons of the CH2OP group. Therefore, disilylated
salicyl alcohol 6b reacts with Lawesson’s reagent 1a
via the cleavage of the most reactive O Si bond of the
CH2O Si fragment under mild conditions used, with
another O Si bond being in the ArO Si fragment.
Strong bands in the region of ꢁ 855–844 cm−1 in the
IR spectra of 7a–d (Table 3) are due to the mutual ρ
CH3(Si) deformation vibrations and P O(C) valence
vibrations. The CH3(Si) symmetrical deformation vi-
brations appear in the region of ꢁ 1260–1255 cm−1.
The electron impact and chemical ionization mass
spectra of 7a and 7b show the mass peaks m/e 436
and 535 of their molecular ions [M]+. and [M + H]+,
respectively.
Disilyl dithiophosphonates 7 containing both
silylthio- and siloxy groups were used as intermedi-
ates for the synthesis of cyclic organothiophospho-
rus compounds. We have shown that disilyl dithio-
phosphonates 7a,b react with dichlorodiphenyl-
germane 8a and dichlorodiphenylstannane 8b in
anhydrous benzene at 20–50◦C for 2–4 h with the
formation of 2-(aryl)-2-thioxo-4,4-diphenyl-6,7-dim-
ethyl-1,5,3,2,4-dioxathiaphosphagermepanes 9a,b
and 2-(4-methoxyphenyl)-2-thioxo-4,4-diphenyl-6,7-
dimethyl-1,5,3,2,4-dioxathiaphosphastannepane 9c,
respectively (Reaction 3, Tables 1–5).
1
observed in the 31P NMR spectrum of 9c. The H
NMR spectra of phosphacycles 9a–c have compli-
cated appearance (Table 4). Two multiplets situated
in the regions of δ = 6.95–7.15 and 7.54–7.63 were
assigned to the protons of two phenyl groups of the
(C6H5)2Ge fragment of 9a. Strong bands in the region
of ꢁ 465–463 and 450 cm−1 in the IR spectra of 9a–c
(Table 3) are due to the asymmetrical valence vibra-
tions of the GePh2 and SnPh2 bonds, respectively. The
chemical ionization spectrum of 9a (Table 5) exhibits
the mass peak m/e 519 because of its molecular ion
[M + H]+.
Along with spectral data, the structure of phos-
phacycles 9 was confirmed by cryoscopy. Molec-
ular weight determinations in anhydrous benzene
of phosphagermepane 9b (found 604.7, calculated
614.9) and phosphastannepane 9c (found 564.6, cal-
culated 562.8) reveal that they do not form dimeric
or polymeric associations.
It is considered of interest to compare the re-
activity of germanes containing the Ge Cl and
Ge S bonds toward disilyl dithiophosphonates 7.
We have shown that dichlorodiphenylgermane 8a
is more reactive than that of S,S-diethyldithio-
diphenylgermane 2. Thus, the optimal conditions of
reaction of disilyl dithiophosphonate 7b with 2 were
defined by the differential thermal analysis. It was
TABLE 5 Mass Spectral Data of the Products Obtained
i -C4 H10, m/e (Irelt, %)
3a
600 [M − Ph ]+· (2).
7aa
436 [M]+· (7); 289 [M − 5 Me]+· (10); 257
[M − 5 Me − S]+· (100).
7ab
7bb
349 [M + H − Me3Si − O]+ (10).
(3)
535 [M + H]+ (5); 505 [M + H − 2 Me]+ (3); 359
[M + H − 3 Me – CHMeOSiMe3]+ (100).
350 [M − Me − O – SiMe3]+· (5); 349 [M − S −
SiMe3]+· (4); 334 [M – S – Me – SiMe3]+· (8).
347 [M + 2 H − S – SiMe3]+·(7); 331 [M + H –
Me − S − SiMe3]+·(7).
Note that dichlorogermane 8a and dichlorostan-
nane 8b take part in the reaction 3 via the cleavage
both Ge Cl or Sn Cl bonds under the conditions
used. Trimethylchlorosilane 10 was also isolated
from the reaction mixtures. Compounds 9a and 9c
were purified by a falling-film distillation, whereas
substance 9b was isolated by column chromatog-
raphy. Phosphagermepanes 9a,b and phosphastan-
nepane 9c are a new type of germanium and tin
cyclic derivatives of tetracoordinated phosphorus
thioacids. Phosphacycles 9a–c were formed as the
7ca
7db
9aa
9ab
9bb
9ca
9cb
259 [M − Me − O − GePh2]+· (100).
519 [M + H]+ (30); 396 [M + H − MeO − Ph]+ (9).
341 [M + H − Ph2Ge − S − O]+(2).
344 [M − 2 Ph − MeO − 2 H]+· (5).
395 [M + 2 H − 2 Ph – Me]+ (16).
aElectron impact, 70 eV.
bChemical ionization, 100 eV.

230 Nizamov et al.
found that this reaction started at 107◦C. To com-
plete the reaction it was carried out at 125◦C for
3 h with the formation of the same crystalline phos-
phagermepane 9b (as a mixture of isomers) (Reac-
tion 4, Tables 1–5). Physical and spectral data of 9b
from reaction 4 were identical with those of 9b from
reaction 3.
(4)
FIGURE 1 Molecular structure of 11.
Dithiaphosphagermetanes and dithiadiphos-
phadigermolanes containing the P S Ge endocyclic
fragment have been reported to be rather thermal un-
stable substances [8,9]. Thus, 2-(4-methoxyphenyl)-
4,4-dimethyl-2-thio-1,3,2,4-dithiaphosphagermetane
undergoes thermal transformations into monome-
ric dimethylgermanium sulfide and 4-methoxyphe-
nylphosphonic anhydride in accordance with the
ꢂ-destruction. These monomeric units form corre-
sponding dimers and trimers [8]. The formation of
similar secondary products could be expected in
the case of phosphagermepanes 9. To verify this
idea the thermal stability of phosphagermepane
9b was studied by differential thermal analysis. It
was found that 9b starts to decompose at 155◦C
and results in the formation of 1,3,5-hexaphenyl-
2,4,6,1,3,5-trithiatrigerminane 11.
It should be emphasized that [10] and other
cyclic organylgermanium sulfides were earlier ob-
tained [11–14]. Tetra(methylgermanium) hexasul-
fide has been shown by X-ray crystallography to
have an adamantane-type structure [12]. However,
the molecular structure of the trimer of diphenylger-
manium sulfide remained unknown. The molecular
and crystal structure of 11 was established by X-ray
single crystal diffraction (Fig. 1). The selected bond
distances, bond angles, and torsion angles of 11 are
listed in Table 6. Inspection proves that 11 exists in
the most thermodynamically stable trans-chair con-
formation.
trioxatriphosphinane 2,4,6-trisulfide [15].
(5)
Thus, dithiophosphonates containing O SiMe3
and S SiMe3 groups obtained on the basis of 5a,b
are efficient intermediates for the synthesis of open
chain and cyclic organothiophosphorus compounds
with the P S Ge or P S Sn fragments.
EXPERIMENTAL
General Data
31P NMR spectra were recorded with a Bruker MSL
400 (162 MHz) instrument in C6H6 with 85% H3PO4
1
as an external reference. The H NMR spectra were
taken on a Bruker MSL-400 (400 MHz) spectrometer
and a Varian T-60 (60 MHz) spectrometer in CDCl3
or CCl4 with (Me3Si)2O as an internal reference.
The IR spectra were obtained in KBr pellets with
an UR-20 infrared spectrophotometer. Mass spectra
(EI, 70 eV; CI, 100 eV) were determined on an M 80
B Hitachi chromatomass spectrometer. Differential
thermal analyses were performed on a Setaram ther-
moanalyzer TG, DTG, DTA equipped with nonserial
heating furnace. Molecular weight determination of
We assume that 9b decomposes via ꢂ-elimina-
tion [10] to give unstable monomeric diphenylger-
manium sulfide and 4-methoxyphenyl methathio-
phosphonate and some nonidentified by-products.
The trimerization of these intermediates leads
to 11 and 2,4,6-tris(4-methoxyphenyl)-1,3,5,2,4,6-

Disilyl Dithiophosphonates in the Synthesis of Open Chain and Cyclic Organothiophosphorus Compounds 231
◦
◦
˚
TABLE 6 Selected Bond Lengths (A), Bond Angles ( ), and Torsion Angles, ( ) in 11
Bond lengths
Ge1 S2
Ge1 S6
Ge1 C1
Ge1 C7
Ge2 S2
Ge2 S4
2.2310(9)
2.2166(9)
1.938(3)
1.935(3)
2.2208(9)
2.2184(9)
Ge2 C13
Ge2 C19
Ge3 S4
Ge3 S6
Ge3 C25
Ge3 C31
1.945(3)
1.945(3)
2.2416(9)
2.2217(8)
1.939(3)
1.938(3)
Bond Angles
S2 Ge1 S6
S2 Ge1 C1
S2 Ge1 C7
S6 Ge1 C1
S6 Ge1 C7
C1 Ge1 C7
S2 Ge2 S4
S2 Ge2 C13
S2 Ge2 C19
S4 Ge2 C13
S4 Ge2 C19
110.65(3)
112.9(1)
103.40(9)
111.14(9)
105.95(9)
112.3(1)
112.72(3)
105.07(9)
112.87(9)
107.26(9)
111.6(1)
C13 Ge2 C19
S4 Ge3 S6
106.8(1)
112.74(3)
114.79(9)
103.37(9)
103.68(9)
114.78(9)
107.7(1)
105.48(4)
107.03(3)
103.58(3)
S4 Ge3 C25
S4 Ge3 C31
S6 Ge3 C25
S6 Ge3 C31
C25 Ge3 C31
Ge1 S2 Ge2
Ge2 S4 Ge3
Ge1 S6 Ge3
Torsion Angles
S6 Ge1 S2 Ge2
C1 Ge1 S2 Ge2
C7 Ge1 S2 Ge2
S2 Ge1 S6 Ge3
C1 Ge1 S6 Ge3
C7 Ge1 S6 Ge3
S2 Ge1 C1 C2
S2 Ge1 C1 C6
S6 Ge1 C1 C2
S6 Ge1 C1 C6
C7 Ge1 C1 C2
C7 Ge1 C1 C6
S2 Ge1 C7 C8
S2 Ge1 C7 C12
S6 Ge1 C7 C8
S6 Ge1 C7 C12
C1 Ge1 C7 C8
C1 Ge1 C7 C12
S4 Ge2 S2 Ge1
C13 Ge2 S2 Ge1
C19 Ge2 S2 Ge1
S2 Ge2 S4 Ge3
C13 Ge2 S4 Ge3
C19 Ge2 S4 Ge3
S2 Ge2 C13 C14
S2 Ge2 C13 C18
40.35(4)
−84.9(1)
153.41(9)
−77.04(4)
49.3(1)
171.54(9)
−0.4(0.3)
−179.2(2)
−125.5(2)
55.8(3)
116.0(3)
−62.7(3)
−97.6(3)
78.2(2)
S4 Ge2 C13 C14
S4 Ge2 C13 C18
C19 Ge2 C13 C14
C19 Ge2 C13 C18
S2 Ge2 C19 C20
S2 Ge2 C19 C24
S4 Ge2 C19 C20
S4 Ge2 C19 C24
C13 Ge2 C19 C20
C13 Ge2 C19 C24
S6 Ge3 S4 Ge2
C25 Ge3 S4 Ge2
C31 Ge3 S4 Ge2
S4 Ge3 S6 Ge1
C25 Ge3 S6 Ge1
C31 Ge3 S6 Ge1
S4 Ge3 C25 C26
S6 Ge3 C25 C26
S6 Ge3 C25 C30
C31 Ge3 C25 C26
C31 Ge3 C25 C30
S4 Ge3 C31 C32
S4 Ge3 C31 C36
S6 Ge3 C31 C32
S6 Ge3 C31 C36
121.9(4)
−63.7(3)
−118.3(3)
56.1(3)
−48.7(3)
139.8(2)
−176.8(2)
11.6(3)
66.3(3)
−105.3(3)
28.40(5)
−90.0(1)
152.92(9)
36.46(4)
161.21(9)
−81.6(1)
104.9(3)
−18.5(3)
160.5(2)
−140.5(3)
38.5(3)
18.9(3)
−165.4(2)
140.4(3)
−43.9(3)
31.27(4)
147.7(1)
−96.4(1)
−67.92(4)
176.9(1)
60.3(1)
157.2(2)
−21.2(3)
−79.6(3)
102.0(3)
1.8(3)
176.2(2)
compounds obtained were carried out on a nonserial
cryoscope with Beckman thermometer.
dices are R= 0.023, Rw = 0.030 for 3797 inde-
pendent reflections. Crystal data for 11: mono-
clinic, space group P21/n, at –150◦C a = 11.825(2),
◦
˚
b = 21.025(4), c = 13.233(2) A, β = 94.95(2) , V =
3
3277.5(1)A , dCalc = 1.57 g/cm3, Z = 4. The structure
˚
X-Ray Crystallography
was solved by the direct method, using the SIR
program [16]. All calculations were carried out on
an Alpha Station 200 computer, using MolEN pro-
grams [17]. Drawings were plotted, using a PLA-
TON program [18]. (CCDC 228694 contains the
supplementary crystallographic data for this paper.
These data can be obtained free of charge via
www.ccdc.cam.ac.uk/conts/retrieving.html or from
Crystal cell data of 11 were measured on an
Enraf-Nonius CAD-4 four circle diffractometer fit-
ted with graphite monochromatized Mo Kꢃ radi-
˚
ation, λ = 0.7103 A, employing the ω/2ꢀ technique
to ꢀ ≤ 27◦. From 4806 reflections measured,
3667 were assumed as observed applying the
conditions I ≥ 3σ(I). The final disagreement in-

232 Nizamov et al.
b.p. 56–57◦C, nD20 1.3892 (cf. lit. [19]: b.p. 57.7◦C, n2D0
1.3885).
The products 9a and 9c were obtained in a sim-
ilar manner (see Tables 1–5).
the Cambridge Crystallographic Data Centre. 12.
Union Road, Cambridge CB2 1EZ, UK; fax: +44 1223
336033; or deposit@ccdc.cam.ac.uk.)
O-Trimethylsilyl-S-(ethylthio)diphenylgermyl-
3,5-di-tert-butyl-4-hydroxyphenyldithiophos-
phonate (3)
1,3,5-Hexaphenyl-2,4,6,1,3,5-trithiatrigerminane
(11)
The mixture of 7b (3.0 g, 5.6 mmol) and 2 (2.0 g,
5.7 mmol) was stirred at 125◦C for 3 h under dry ar-
gon. The mixture was stored at ∼20◦C for 1 month.
The precipitate formed was filtered, washed with an-
hydrous diethyl ether, dried under vacuum (0.5 mm
Hg) for 2 h, and gave 2.2 g (63%) of 9b, m.p. 72◦C.
The compound 9b was heated at 155–160◦C for 2 h
to yield crystalline 11 (0.2 g). Distillation of filtrate
gave 4 (0.8 g, 53%), b.p. 132–133 ◦C, nD20 1.4503.
Compound 1 (1.0 g, 2.2 mmol) was added dropwise
under dry argon with stirring at 20◦C to the sus-
pension of 0.8 g (2.3 mmol) of 2 in 5 ml of anhy-
drous benzene, and stirring was continued for 4 h at
20◦C. The mixture was evaporated at reduced pres-
sure (0.5 and then 0.03 mm Hg) at 40◦C for 2 h with
use of a trap cooled by liquid nitrogen and gave 0.9 g
(60%) of crude 3. Crude 3 was chromatographed on a
silica-gel column with anhydrous benzene as eluant
to yield 0.6 g (40%) of pure 3 (see Tables 1–5). Dis-
tillation of the contents of the liquid nitrogen trap
gave 4 (0.2 g, 67%), b.p. 128–130◦C, nD20 1.4509 (cf.
lit. [19]: b.p. 130◦C, nD20 1.4512).
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Trimethylsilyl-4-Methoxyphenyldithiophos-
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The mixture of 6a (94.3 g, 402.1 mmol) and 5a
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h under dry argon. The mixture was evaporated at
reduced pressure (0.1 mm Hg) at 40◦C for 1 h and
under a higher vacuum (0.07 mm Hg) at 40◦C for 1 h
and gave 132.7 g (76%) of crude 7a. Product 7a (98.0
g, 56%) was isolated from the residue by means of a
falling-film distillation (see Tables 1–5).
The products 7b,c were obtained in a similar
manner (see Tables 1–5).
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icon Relat Elem 1995, 107, 99–105.
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2-3,5-Di-tert-butyl-4-hydroxyphenyl 2-Thioxo-
4,4-diphenyl-6,7-dimethyl-1,5,3,2,4-
dioxathiaphosphagermepane (9b)
Compound 8a (2.0 g, 6.7 mmol) was added drop-
wise under dry argon with stirring at 20◦C to 3.6 g
(6.7 mmol) of 7b in 5 ml of anhydrous benzene, and
stirring was continued for 2 h at 50◦C. The mixture
was filtered. The filtrate was evaporated at reduced
pressure (0.5 and 0.03 mm Hg) at 40◦C with use of a
trap cooled by liquid nitrogen and gave 3.2 g (78%)
of crude 9b (the mixture of isomers). Liquid 9b was
chromatographed on a silica-gel column with anhy-
drous CH2Cl2 as eluant to yield 1.3 g (32%) of 9b
(R 0.82 and 0.96, Silufol UV-254, CH2Cl2) that was
f
crystallized by removing the eluant under reduced
pressure (see Tables 1–5). Distillation of the con-
tents of the liquid nitrogen trap gave 10 (0.9 g, 60%),