Synthesis, spectroscopic characterization and structural studies of organotin monothiocarbonates. Crystal structures of Ph3Sn[SCO2Me] and Ph3Sn[SCO2(i-Pr)]

Article abstract of DOI:10.1139/v00-116

O-alkyl monothiocarbonate (monoxanthate) derivatives of tin were obtained by the reaction of a sodium salt of the monothiocarbonic acid with an organotin chloride to give Ph₃Sn[SCO₂R], Ph₂Sn[SCO₂R]₂, and Me₃Sn[SCO₂R], where R = Me and i-Pr. The compounds have been characterized by infrared, Raman, ¹H NMR, and ¹³C NMR spectroscopy, as well as mass spectrometry, and in two cases by X-ray crystallography. Ph₃Sn[SCO₂Me] (1) and Ph₃Sn[SCO₂(i-Pr)] (2), crystallize in the triclinic space group P1 (no. 2) with cell parameters a = 10.218(4), b = 10.568(6), c = 9.366(7) A, α = 106.73(5), β = 96.99(5), γ = 85.55(4)°, V = 960(1) A³, and Z = 2 for 1; and a = 14.793(2), b = 17.856(3), c = 9.813(3) A, α = 103.86(5), β = 98.36(5), γ = 106.85(4)°, V = 2343(1) A³, and Z = 2 for 2. The latter has two molecules in the asymmetric unit. The immediate environment about tin in both 1 and 2 is that of the expected distorted tetrahedron. However, the orientation of the monothiocarbonate group is such that there is an Sn-O intramolecular interaction of 3.040(8) for 1 and 3.05(2) A on average for 2. Thus, the considerable distortion is consistent with a tendency to form a five-coordinate, trigonal bipyramidal species with one of the O-Sn-C angles approaching 180°(153.4(4) for 1 and an average of 157.1(6) for 2). Estimations of the Pauling partial bond orders suggest this weak Sn-O interaction is slightly stronger than the corresponding Ge-O interaction in the analogous germanium derivative, Ph₃Ge[SCO₂Me].

Full text of DOI:10.1139/v00-116

1214
Synthesis, spectroscopic characterization and
structural studies of organotin
monothiocarbonates. Crystal structures of
Ph3Sn[SCO2Me] and Ph3Sn[SCO2(i-Pr)]
John E. Drake and Jincai Yang
Abstract: O-alkyl monothiocarbonate (monoxanthate) derivatives of tin were obtained by the reaction of a sodium salt
of the monothiocarbonic acid with an organotin chloride to give Ph3Sn[SCO2R], Ph2Sn[SCO2R]2, and Me3Sn[SCO2R],
1
where R = Me and i-Pr. The compounds have been characterized by infrared, Raman, H NMR, and 13C NMR
spectroscopy, as well as mass spectrometry, and in two cases by X-ray crystallography. Ph3Sn[SCO2Me] (1) and
Ph3Sn[SCO2(i-Pr)] (2), crystallize in the triclinic space group P1 (no. 2) with cell parameters a = 10.218(4), b =
10.568(6), c = 9.366(7) Å, α = 106.73(5), β = 96.99(5), γ = 85.55(4)°, V = 960(1) Å3, and Z = 2 for 1; and a =
14.793(2), b = 17.856(3), c = 9.813(3) Å, α = 103.86(5), β = 98.36(5), γ = 106.85(4)°, V = 2343(1) Å3, and Z = 2 for
2. The latter has two molecules in the asymmetric unit. The immediate environment about tin in both 1 and 2 is that
of the expected distorted tetrahedron. However, the orientation of the monothiocarbonate group is such that there is an
Sn-O intramolecular interaction of 3.040(8) for 1 and 3.05(2) Å on average for 2. Thus, the considerable distortion is
consistent with a tendency to form a five-coordinate, trigonal bipyramidal species with one of the O-Sn-C angles
approaching 180o (153.4(4) for 1 and an average of 157.1(6) for 2). Estimations of the Pauling partial bond orders
suggest this weak Sn-O interaction is slightly stronger than the corresponding Ge-O interaction in the analogous
germanium derivative, Ph3Ge[SCO2Me].
Key words: structure, tin, methyl, phenyl, isopropyl, monothiocarbonates.
Résumé : On a préparé des dérivés de l’étain avec du monothicarbonate (monoxanthate) de O-alkyle (Ph3Sn[SCO2R],
Ph2Sn[SCO2R] et Me3Sn[SCO2R] dans lesquels R = Me ou i-Pr) en faisant réagit du sel de sodium de l’acide
monothiocarbonique avec un chlorure d’organoétain. On a caractérisé ces composés par spectroscopies infrarouge,
1
Raman et RMN du H et du 13C ainsi que par spectroscopie de masse et, dans deux cas, par diffraction des rayons X.
Le Ph3Sn[SCO2Me], 1, et Ph3Sn[SCO2i-Pr], 2, cristallisent dans le groupe d’espace P1 (no. 2) avec a = 10,218(4), b =
10,568(6) et c = 9,366(7) Å, α = 106,73(5), β = 96,99(5) et γ = 85,55(4)°, V = 960(1) Å3 et Z = 2 pour le composé 1
et a = 14,793(2), b = 17,856(3) et c = 9,813(3) Å, α = 103,86(5), β = 98,36(5) et γ = 106,85(4)°, V = 2343(1) Å3 et
Z = 2 pour le composé 2. Ce dernier composé comporte deux molécules dans la maille asymétrique. L’environnement
immédiat autour de l’étain de ces deux composés correspond à celui attendu pour un tétraèdre déformé. Toutefois,
l’orientation du groupe monothiocarbonate est tel que l’on observe une interaction Sn-O intramoléculaire de 3,040(8) Å
pour 1 et de 3,05(2) Å pour 2. La déformation importante est donc en accord avec une tendance à former une espèce
pentacoordinée trigonale bipyramidale dans laquelle les angles O-Sn-C se rapprochent de 180° (153,4(4) pour 1 et une
moyenne de 157,1(6) pour 2). Des évaluations à partir des ordres partiels de liaison de Paulin suggèrent que cette in-
teraction Sn-O faible est un peu plus forte que l’interaction correspondante Ge-O du composé germaniun analogue,
Ph3Ge[SCO2Me].
Mots clés : structure, étain, méthyle, phényle, isopropyle, monothiocarbonates.
[Traduit par la Rédaction] Drake and Yang 1221
Introduction
most of the relatively few reports have involved transition
metal complexes (1). In addition to reports on alkali salts
(2), two reports by us have appeared on main group element
monothiocarbonates describing some organotellurium (3)
and organogermanium (4) derivatives. Considerably more
O-alkyl dithiocarbonate (xanthate) derivatives have been
extensively studied but the chemistry of monothiocarbonates
(monoxanthates) has received considerably less attention and
Received January 20, 2000. Published on the NRC Research Press website on September 1, 2000.
J.E. Drake.1 Chemistry and Biochemistry, University of Windsor, Windsor, ON N9B 3P4, Canada.
J. Yang. Research and Development, Petro-Canada Lubricants, Mississauga, ON L5K 1A8, Canada.
1Author to whom correspondence may be addressed. Telephone: (519) 253-4232. Fax: (519) 973-7098. e-mail: ak4@uwindsor.ca
Can. J. Chem. 78: 1214–1221 (2000)
© 2000 NRC Canada

Drake and Yang
1215
work has appeared on dithio derivatives of tin than of ger-
manium, but we were unable to find any reports on
monothiocarbonate organotin derivatives. Surprisingly, we
found these even more difficult to isolate pure than their
germanium analogues but we were able to confirm the for-
mation of five O-alkyl monothiocarbonate derivatives
Ph3Sn[SCO2R] (R = Me and i-Pr), Ph2Sn[SCO2(i-Pr)]2,
Ph2SnCl[SCO2(i-Pr)], and MeSn[SCO2Me] by NMR, infra-
red, and Raman spectroscopy, as well as mass spectrometry.
We also have obtained the X-ray crystal structures of
Ph3Sn[SCO2Me](1) and Ph3Sn[SCO2(i-Pr)](2).
Among the many reports on dithio derivatives of tin, those
of relevance to this work include discussions of ligand coor-
dination modes and coordination number in a variety of
dithiocarbamates (5), a series of publications on dithiocar-
bonates (6), and a structural study of Ph3Sn[S2CO(i-Pr)] (7).
An examination of tin(IV) 1-pyrrolecarbothioates (8), in-
cluding Ph3Sn[SOCNC4H4], and a comparison of the struc-
tures of the monothiocarbamate, Ph3Sn[SCON(CH2)4O],
with the analogous dithiocarbamate are also of interest (9).
Bidentate linkages appear to be favored in organotin deriva-
tives with dithio-ligands as exemplified in dithiophosphates
such as Ph2Sn[S2P(Oi-Pr)2]2 (10) and dithiocarbamates such
as BuSn[S2CN(Et)2]3 (11) in both of which tin atoms are in
octahedral sites. However, monodentate linkages appear to
be often found with triphenyltin derivatives such as in
Ph3Sn[S2P(OEt)2] (12). The range of mono-, aniso-, and bi-
dentate ligands will be discussed in some detail.
(CDCl3) δ 3.63 [3H, OCH3, s]; 7.41–7.44 [9H, Sn-C6H5 –
meta + para]; 7.63–7.68 [6H Sn-C6H5 – ortho]. 13C NMR:
(CDCl3) δ 54.82 [OCH3]; 129.03, 130.04, 136.57, 136.74
[Sn-C6H5]. In the same fashion Ph3Sn[SCO2(i-Pr)] (2) was
prepared as a colorless solid. Recrystallization from a
CH2Cl2 – n-hexane mixture gave colorless crystals (0.30 g,
0.71 mmol, yield 86%), mp 92–93°C. Peaks in the mass
spectrum corresponding to 120Sn were seen at m/z (relative
intensity): 469 ((Ph3SnSCO2(i-Pr)
–
H)+, 2%), 393
((Ph2SnSCO2(i-Pr))+, 8%), 351 ((Ph3Sn)+, 100%), 333
((Ph3SnO(i-Pr))+, 8%), 291 ((Ph2SnOH)+, 50%), 274
((Ph2Sn)+, 30%), 197 ((PhSn)+, 50%). IR (Raman) (cm–1)
main features: ν(O=CSOC) 1663 vs, ν((OSC-O(i-Pr)) 1169
vs, ν(OSO-CH(CH3)2) 1093 vs, p-phenyl [1001 (100)],
π(SCO2) 848 m, f-phenyl 731 s, v-phenyl 698 s, ν(SnS-C)
655 w [657 (45)], y-phenyl 446 ms, δ(SCO2) 433 sh, ν(Sn-S)
1
[335 (15)]. H NMR: (CDCl3) δ 1.04 [6H, OCH(CH3)2, d,
J(HH) 6.2 Hz]; 4.88 [1H, OCH, sept, J(HH) 6.2 Hz]; 7.40–
7.42 [9H, Sn-C6H5 – meta + para]; 7.64–7.67 [6H Sn-C6H5
– ortho]. 13C NMR: (CDCl3) δ 21.61 [OCCH3]; 72.65
[OCH]; 129.98, 129.96, 136.47, 136.71 [Sn-C6H5].
Preparation of Ph2Sn[SCO2(i-Pr)]2 (3)
Typically, Ph2SnCl2 (0.25 g, 0.72 mmol) and NaSCO2(i-Pr)
(0.25 g, 1.76 mmol) were placed in a flask and solvent
(CH2Cl2, ca. 15 mL) was added under N2. The mixture was
stirred for 2 h at room temperature, followed by filtration
and evaporation under vacuum to give Ph2Sn[SCO2(i-Pr)]2,
3, (0.3 g, 0.59 mmol) as a colorless solid, (0.30 g, 0.59 mmol),
yield 81.5%, mp 83–84°C. Peaks in the mass spectrum cor-
responding to 120Sn in a typical tin cluster were seen at m/z
(relative intensity): 512 ((Ph2Sn[SCO2(i-Pr)]2)+, 1%), 393
((Ph2SnSCO2(i-Pr))+, 30%), 333 ((Ph3SnO(i-Pr))+, 45%),
291 ((Ph2SnOH)+, 100%), 274 ((Ph2Sn)+, 65%), 197
((PhSn)+, 35%). Attempts at recrystallization failed to yield
any X-ray quality crystals. IR (Raman) (cm–1) main features:
ν(O=CSOC) 1642 vs, ν((OSC-O(i-Pr)) 1176 vs, ν(OSO-
CH(CH3)2) 1091 vs, p-phenyl [999 (100)], π(SCO2) 847 ms,
f-phenyl 732 ms, v-phenyl 695 ms, ν(SnS-C) 655 vw [658
(45)], y-phenyl 445 m, δ(SCO2) 428 m, ν(Sn-S) [344 (15)].
1H NMR: (CDCl3) δ 1.06 [12H, OCH(CH3)2, d, J(HH)
6.2 Hz]; 4.86 [2H, OCH, sept, J(HH) 6.2 Hz]; 7.43–7.45
[6H, Sn-C6H5 – meta + para]; 7.82–7.85 [4H Sn-C6H5 –
ortho]. 13C NMR: (CDCl3) δ 21.58 [OCCH3]; 73.48 [OCH3];
129.07, 130.46, 135.35, 135.73 [Sn-C6H5].
Experimental
Materials
The starting materials (Ph3SnCl, Ph2SnCl2, and Me3SnCl)
were obtained from Aldrich; all starting materials being used
as supplied. All solvents were dried and distilled prior to use
and all reactions were carried out under anhydrous condi-
tions. The salts, NaSCO2R, where R = Me and i-Pr, were
prepared as described in the literature (4) and their purity
1
checked by H and 13C NMR spectroscopy. No further puri-
fication was necessary.
Preparation of Ph3Sn[SCO2Me] (1) and Ph3Sn[SCO2(i-Pr)]
(2)
Typically, Ph3SnCl (0.25 g, 0.65 mmol) and an excess of
dried NaSCO2Me (0.10 g, 0.88 mmol) were placed in a pre-
viously evacuated flask and solvent (CH2Cl2, ca. 15 mL)
was added under N2. The mixture was stirred for 2 h at room
temperature, followed by filtration to remove NaCl and ex-
cess of starting salt, and then evaporation under vacuum
gave Ph3Sn[SCO2Me] (1) as a colorless solid. Recrystalli-
zation from a CH2Cl2 – n-hexane mixture gave colorless
crystals (0.20 g, 0.45 mmol), yield 70%, mp 86°C. Peaks in
the mass spectrum corresponding to 120Sn in a typical tin
cluster were seen at m/z (relative intensity): 442
((Ph3SnSCO2Me)+, 3%), 365 ((Ph2SnSCO2Me)+, 10%), 351
((Ph3Sn)+, 100%), 305 ((Ph2SnOMe)+, 45%), 274 ((Ph2Sn)+,
30%), 197 ((PhSn)+, 9%). IR (Raman) (cm–1) main features:
ν(O=CSOC) 1669 vs, ν(OSC-OMe) 1148 vs br, ν(OSO-CH3)
1090 sh, p-phenyl [1002 (100)], π(SCO2) 817 ms, f-phenyl
731 vs, v-phenyl 698 vs, ν(SnS-C) 658 m [658 (55)], y-
Formation and identification of Ph2SnCl[SCO2(i-Pr)]
(4) and Me3Sn[SCO2Me] (5)
Typically, Ph2SnCl2 (0.30 g, 0.87 mmol) and dried
NaSCO2(i-Pr) (0.12 g, 0.87 mmol) were introduced into a
round-bottomed flask, followed by the addition of dried
CH2Cl2 (ca. 15 mL). The mixture was stirred for ca. 2 h at
which time the NaCl that had formed was filtered off and the
solvent allowed to evaporate under vacuum to produce
Ph2SnCl[SCO2(i-Pr)] (4) as a white solid (0.31 g, 0.73 mmol,
yield 83%). IR (Raman) (cm–1) main features: ν(O=CSOC)
1629 ms, br, ν((OSC-O(i-Pr)) 1261 s, ν(OSO-CH(CH3)2)
1095 vs, p-phenyl [1000 (100)], π(SCO2) 803 ms br,
f-phenyl 728 vs, v-phenyl 692 vs, ν(SnS-C) 656 mw [658
(45)], y-phenyl 448 m br, δ(SCO2) 430 sh, ν(Sn-S) [340 (5)],
ν(Sn-Cl) [276 (9)]. 1H NMR: (CDCl3) δ 1.26 [6H,
1
phenyl 447 s, δ(SCO2) 426 m, ν(Sn-S) [333 (10)]. H NMR:
© 2000 NRC Canada

1216
Can. J. Chem. Vol. 78, 2000
Table 1. Summary of crystal data, intensity collection, and structural refinement for Ph3[SnSCO2Me] (1) and 2Ph3Sn[SCO2(i-Pr)] (2).
Parameter
1
2
a (Å)
10.218(4)
14.793(2)
b (Å)
10.568(6)
17.856(3)
c (Å)
9.366(7)
9.813(3)
α (°)
106.73(5)
103.86(2)
β (°)
96.99(5)
98.36(2)
γ (°)
V (Å3)
85.55(4)
960(1)
106.85(1)
2343(1)
Crystal system
Space group
Mol. wt. (g mol–1)
Z
Triclinic
P1 (no. 2)
444.11
2
Triclinic
P1(no. 2)
983.33
2
Crystal dimensions (mm)
ρ (calcd.) (g cm–3)
µ, cm–1
0.41 × 0.36 × 0.21
1.52
14.46
0.45 × 0.40 × 0.21
1.33
11.9
Transmission factors
Temperature (°C)
Radiation (Å)
Monochromator
Scan method
0.58–1.00
23
Mo Kα 0.71096
Highly oriented graphite
ω – 2θ
32
50
0.73–1.00
23
Mo Kα 0.71096
Highly oriented graphite
ω – 2θ
16
45
Scan speed (°/min)
Max. (2θ)
Total reflections measured
No. of unique data
No. of obsd. data (I ≥ 3σ (I))]
No. of parameters (NP)
R = ∑1Fo| – | Fc1/ ∑|F o|
Rw = [∑w( |Fo| – |Fc|)2/∑wF o2 )]1/2
3591
3382
1619
127
0.0543
0.0452
1.72
5218
4929
1511
169
0.0544
0.0583
1.85
Goodness of fit
Largest shift/e.s.d, final cycle
Largest residual electron density (e Å–3)
0.001
0.09
0.001
0.76
OCH(CH3)2, d, J(HH) 6.2 Hz]; 5.00 [1H, OCH, sept, J(HH)
6.2 Hz]; 7.47–7.50 [6H, Sn-C6H5 – meta + para]; 7.84–7.87
[4H Sn-C6H5 – ortho]. 13C NMR: (CDCl3) δ 21.74
[OCCH3]; 75.38 [OCH3]; 129.26, 130.98, 135.19, 136.61
[Sn-C6H5]. Attempts at recrystallization did not yield any
crystals, but rather resulted in decomposition. In a similar
manner as described for the preparation of 1 and 2,
Me3Sn[SCO2Me] (5), was formed as a colorless viscous liq-
uid by starting with Me3SnCl and an excess of NaSCO2Me.
IR (Raman) (cm–1) main features: ν(O=CSOC) 1630 m,
ν(OSC-OMe) 1260 vs, ν(OSO-CH3) 1034 vs br, π(SCO2)
Physical measurements
Infrared spectra were recorded on a Nicolet 5DX FT spec-
trometer as KBr pellets or oils smeared between KBr win-
dows in the region 4000–400 cm–1, and far infrared spectra
on a Bomem DA3 infrared spectrometer between polyethyl-
ene films as oils or Nujol mulls. The Raman spectra were re-
corded on samples in sealed glass capillaries on a JEOL-XY
Raman spectrometer using the 5145 Å exciting line of an ar-
1
gon ion laser. The H and 13C {H} NMR spectra were re-
corded on a Bruker 300 FT/NMR spectrometer at 300.133
and 75.471 MHz, respectively, in CDCl3 using Me4Si as in-
ternal standard. All NMR spectra were run at ambient tem-
perature and under standard operating conditions. The
melting points were determined on a Fisher–Johns appara-
tus. The mass spectra were recorded on a Kratos Profile GC-
MS Spectrometer.
865 s, ρ(SnCH3) 799 vs, ν(SnS-C) 662 m, ν(Sn-Casymm
)
1
532 m, ν(Sn-Csymm) 506 mw. H NMR: (CDCl3) δ 0.53 [9H,
Sn(CH3)3, J(SnH) 64.2 Hz], 3.68 [3H, OCH3]. 13C NMR:
(CDCl3) δ –2.50 [SnCH3], 53.51 [OCH3]. For both 4 and 5,
the 1H and 13C NMR spectra taken immediately after separa-
tion indicated the presence of only one product.
X-ray crystallographic analysis
Attempted formation and identification of
Ph2Sn[SCO2Me]2 and Ph2SnCl[SCO2Me]
Colorless block crystals of Ph3Sn[SCO2Me] (1) and
Ph3Sn[SCO2(i-Pr)] (2) were sealed in thin-walled glass cap-
illaries and mounted on a Rigaku AFC6S diffractometer,
with graphite-monochromated MoKα radiation. Operating at
50 kV and 35 mA.
Cell constants corresponded to triclinic cells whose di-
mensions are given in Table 1, along with other experimental
details. Based on statistical analysis of intensity distribution
In a manner similar to the successful preparation of 3 and
4, substituting NaSCO2Me for NaSCO2(i-Pr) did not result
in the formation of pure Ph2Sn[SCO2Me]2 or Ph2SnCl[SCO2Me]
but rather in mixtures. The NMR spectra in each case were
consistent with the presence of differing amounts of both of
the desired compounds.
© 2000 NRC Canada

Drake and Yang
1217
Table 2. Selected interatomic distances (Å) and angles (°) for
Ph3Sn[SCO2Me] (1)
Table 3. Selected interatomic distances (Å) and angles (°) for
2Ph3Sn[SCO2(i-Pr)] (2)
Bond
Distance (Å)
Bond
Angle (°)
Bond
Distance (Å) Bond
Angle (°)
Sn(1)—S(1)
Sn(1)—C(3)
Sn(1)—C(9)
Sn(1)—C(15)
S(1)—C(1)
C(1)—O(1)
C(1)—O(2)
O(2)—C(2)
Sn(1)--O(1)
S(1)--O(1)
2.444(4)
2.10(1)
2.12(1)
2.12(1)
1.76(1)
1.20(1)
1.34(1)
1.43(1)
3.040(8)
2.636(9)
S(1)-Sn(1)-C(3)
S(1)-Sn(1)-C(9)
S(1)-Sn(1)-C(15)
C(3)-Sn(1)-C(9)
C(3)-Sn(1)-C(15)
C(9)-Sn(1)-C(15)
Sn(1)-S(1)-C(1)
S(1)-C(1)-O(1)
S(1)-C(1)-O(2)
O(1)-C(1)-O(2)
C(1)-O(2)-C(2)
S(1)-Sn(1)--O(1)
O(1)--Sn(1)-C(15)
97.5(3)
112.3(3)
112.2(3)
112.6(4)
111.4(4)
109.9(4)
95.4(5)
125(1)
109.2(9)
126(1)
115(1)
56.2(2)
153.4(4)
Sn(1)—S(1)
Sn(1)—C(5)
Sn(1)—C(1)
Sn(1)—C(1)
S(1)—C(1)
C(1)—O(1)
C(1)—O(2)
O(2)—C(2)
Sn(1)--O(1)
S(1)--O(1)
2.42(1)
2.12(2)
2.11(2)
2.16(3)
1.80(4)
1.16(5)
1.35(6)
1.52(5)
3.04(3)
2.66(3)
S(1)-Sn(1)-C(5)
S(1)-Sn(1)-C(11)
S(1)-Sn(1)-C(17)
C(5)-Sn(1)-C(11)
C(5)-Sn(1)-C(17)
C(11)-Sn(1)-C(15)
Sn(1)-S(1)-C(1)
S(1)-C(1)-O(1)
113.1(7)
100.7(8)
110.3(8)
106.7(9)
114.2(8)
111(1)
94(2)
127(4)
106(3)
127(4)
S(1)-C(1)-O(2)
O(1)-C(1)-O(2)
C(1)-O(2)-C(2)
118(2)
S(1)-Sn(1)--O(1)
O(1)--Sn(1)-C(11)
S(2)-Sn(2)-C(27)
S(2)-Sn(2)-C(33)
S(2)-Sn(2)-C(39)
C(27)-Sn(2)-C(33)
C(27)-Sn(2)-C(39)
C(33)-Sn(2)-C(39)
Sn(2)-S(2)-C(23)
S(2)-C(23)-O(3)
S(2)-C(23)-O(4)
O(3)-C(23)-O(4)
C(23)-O(4)-C(24a)
C(23)-O(4)-C(24b)
S(2)-Sn(2)--O(3)
O(3)--Sn(2)-C(33)
56.8(6)
157.5(9)
111.2(7)
100.3(8)
100.6(7)
109.5(8)
114.3(7)
112(1)
97(2)
122(4)
113(3)
125(4)
Sn(2)—S(2)
Sn(2)—C(27)
Sn(2)—C(33)
Sn(2)—C(39)
S(2)—C(23)
C(23)—O(31) 1.25(5)
C(23)—O(4)
O(4)—C(24a)
2.46(1)
2.16(2)
2.13(2)
2.08(2)
1.78(5)
and the successful solution and refinement of the structures,
the space group was determined to be P1 (no. 2) for both 1
and 2. The data were corrected for Lorentz and polarization
effects and an empirical absorption correction was applied.
In the case of 2, data collection stopped automatically at
45.0° because the crystal had decayed, therefore a decay
correction was applied.
The structure was solved by direct methods (13) and all
calculations were performed using the TEXSAN (14) crys-
tallographic software package of Molecular Structure Corp.2
All of the non-hydrogen atoms were refined anisotropically
for 1, but for 2 only the thio carbon atom was treated
anisotropically along with the other non-hydrogen atoms.
The phenyl groups were treated as fixed rings with C—C
distances set at 1.39 Å in 2 and an attempt was made to
model the i-Pr group of one of the molecules in the asym-
metric unit which was badly disordered. Hydrogen atoms,
other than those of the disordered group, were included in
their idealized position with C—H set at 0.95 Å and isotro-
pic thermal parameters set at 1.2 times that of the carbon to
which they were attached.
The unweighted and weighted agreement factors and stan-
dard deviation of an observation of unit weight3 are given in
Table 1. Plots of ∑w(*Fo* – *Fc*)2 versus *Fo*, reflection or-
der in data collection, sin θ /λ, and various classes of indices
showed no unusual trends. Important distances and bond an-
gles are given in Tables 2 and 3 and the molecular structures
of the two compounds are displayed as ORTEP diagrams in
Figs. 1–3. The final atomic coordinates and equivalent iso-
tropic thermal parameters for the non-hydrogen atoms,
anisotropic thermal parameters for non-hydrogen atoms, fi-
nal fractional coordinates and thermal parameters for hydro-
1.31(6)
1.6(1)
O(4)—C(24b) 1.4(1)
Sn(2)--O(3)
S(2)--O(3)
3.06(3)
2.66(3)
111(4)
108(4)
56.4(6)
156.7(9)
gen atoms, and all bond distances and angles have been de-
posited.4
Calculation of Pauling partial bond orders
The formula proposed by Pauling (15) for calculating the
bond orders of partial bonds is given by dn – d = –0.60 log
n, where dn is the bond length for bond number, n, and d is
the length of the single bond of the same type. Based on the
C—C single bond of 1.54 Å, Pauling’s formula gives a bond
length of 1.36 Å for n = 2; 1.72 Å for n = 0.5; and 1.90 Å
for n = 0.25. These give percentage increases in bond length
for the partial bonds of approximately 12 and 23% respec-
tively for n = 0.5 and 0.25. It is reasonable to assume that
similar relationships relating bond order to interatomic dis-
tances for the much longer secondary interactions or partial
bonds involving Sn and S should utilize percentage differ-
ences “normalized” to 1.54 as follows rather than absolute
differences. Pauling’s relationship, which can be written
as n = 10X, where X = (d – dn)/0.6, can be modified to allow
2 Least-squares function minimized: ∑ w(, Fo, – ,Fc,)2, where w = 4F 2o (F 2o ), σ 2(F 2o ) = [S2C + R2B) + ( pF 2o )2]/(Lp)2, S = scan rate, C = total
integrated peak count, R = ratio of scan time to background counting time, Lp = Lorentz-polarization factor, and p = p factor.
3 Standard deviation of an observation of unit weight: [∑w( , Fo , – , Fc ,)2/No – Nv)1/2, where No = number of observations and Nv = number of
variables.
4 Supplementary material may be purchased from the Depository of Unpublished Data, Document Delivery, CISTI, National Research Coun-
cil Canada, Ottawa, ON, Canada K1A 0S2 (http://www.nrc.ca/cisti/irm/unpub_e.shtml). Tables of atomic coordinates for the structure(s) re-
ported in this paper have been deposited with the Cambridge Crystallographic Data Centre. Copies of the data can be obtained, free of
charge, on application to the Director, CCDC, 12 Union Road, Cambridge CB2 1EZ, U.K. (Fax: 44-1223-336033 or e-mail: de-
posit@ccdc.cam.ac.uk). Structure factor amplitudes are no longer being deposited and may be obtained directly from the author.
© 2000 NRC Canada

1218
Can. J. Chem. Vol. 78, 2000
Fig. 1. ORTEP plot of the molecule Ph3Sn[SCO2Me] (1). The at-
oms are drawn with 30% probability ellipsoids. Hydrogen atoms
omitted for clarity.
Fig. 2. ORTEP plot of the two molecules of Ph3Sn[SCO2(i-Pr)]
(2) in the asymmetric unit. The atoms are drawn with 30% prob-
ability ellipsoids. Hydrogen atoms are omitted and only one set
of the carbon atoms in partially occupied positions are shown for
the disordered i-Pr group for clarity.
for percentage differences “normalized” to 1.54 to give X =
[1.54(d – dn)/d]/0.6 or X = 2.57(d – dn)/d. Assuming the
Sn—S single bond length approximates to the sum of the re-
spective covalent radii (16), the corresponding values for
Sn—S single and partial bonds for various values of n are
2.40 Å (n = 1.0), 2.50 (0.75), 2.68 (0.50), 2.95 (0.25), and
3.33 Å (n = 0.10). Similarly, relative to a Sn—O single bond
length of 2.14 Å, the corresponding values for Sn—O partial
bonds are 2.24 (0.75), 2.40 (0.50) 2.65 (0.25), and 2.97 Å
(n = 0.10); relative to a Ge—O single bond length of 1.96 Å,
the Ge—O partial bonds are 2.05 (0.75), 2.19 (0.50), 2.43
(0.25), and 2.72 Å (n = 0.10); and relative to a Ge—S single
bond length of 2.26 Å, the corresponding values for Ge—S
partial bonds are 2.37 (0.75), 2.53 (0.50), 2.79 (0.25), and
3.13 Å (n = 0.10). These calculated values appear to be
compatible with the sum of the van der Waals radii of Sn,
Ge, S, and O (17) and by way of comparison, the “valen-
cies” for partial Sn—O bonds have been calculated as 2.43
(0.30) and 2.66 (0.20) (18).
Fig. 3. ORTEP plots illustrating the core around tin including
the Sn-O interaction for (a) the molecule Ph3Sn[SCO2Me] (1)
and (b) the molecule of Ph3Sn[SCO2(i-Pr)] (2) that does not con-
tain a disordered i-Pr group. The atoms are drawn with 30%
probability ellipsoids. Hydrogen atoms and the carbon atoms of
the phenyl rings other than those attached to tin omitted for clarity.
Results and discussion
The preparation of O-alkyl monothiocarbonate derivatives
of triphenyl-, diphenyl-, and trimethyl-tin(IV) compounds
was attempted by the reaction of the sodium salt of the
monothiocarbonic acid in dried CH2Cl2 as solvent with the
appropriate organotin chloride using a standard Schlenk line
in accord with the reactions
[1]
[2]
[3]
R3SnCl + NaSCO2R′ | R3Sn[SCO2R′] + NaCl
R2SnCl2 + 2NaSCO2R′ | R2Sn[SCO2R′]2 + 2NaCl
R2SnCl2 + NaSCO2R′ | R2SnCl[SCO2R′] + NaCl
where R = Me, Ph, R′ = Me, i-Pr.
© 2000 NRC Canada

Drake and Yang
1219
The compounds Ph3Sn[SCO2Me] (1), Ph3Sn[SCO2(i-Pr)]
(2), Ph2Sn[SCO2(i-Pr)]2 (3), Ph2SnCl[SCO2(i-Pr)] (4), and
Me3Sn[SCO2Me] (5) were isolated but only 1 and 2 gave X-
ray quality crystals. In reactions [1] and [2], the salts were
used in considerable excess relative to the stoichiometric re-
quirements to ensure complete reaction. By contrast, exact
stoichiometric amounts were used in reaction [3] to favor the
formation of the mixed chloro derivatives. When reactions
[2] and [3] were attempted using NaSCO2Me, only mixtures
containing Ph2Sn[SCO2Me]2 and Ph2SnCl[SCO2Me] re-
sulted in both cases. In general, all of the compounds are
susceptible to moisture and air on exposure to the atmo-
sphere, and all were readily dissolved in chloroform —
which was therefore used as the preferred solvent for record-
ing NMR spectra.
Ph3Ge[SCO2Me] and Ph3Ge[SCO2(i-Pr)] (4), the three C-
Sn-C angles range from 109.9(4) to 112.6(4)° in 1 and
106.7(9) to 114.3(7)° in 2 with averages of 111.3(14) and
111.3(29)°, respectively; while those of the S-Sn-C angles
range from 97.5(3) to 112.3(3)° in 1 and 100.7(8) to
113.1(7)° in 2 with averages of 107(8) and 107(6)o, respec-
tively. Alternatively, it is notable that one of the S-Sn-C an-
gles is considerably smaller (97.5(3) in 1 and 100.5(3)°
average in 2) than the rest of the five angles around Sn (av-
erage 111.7(11) in 1 and 111.1(24)° in 2); all five being
close to or slightly larger than the all-tetrahedral angle. A
similar phenomenon was noted for Ph3Sn[SCO2N(CH2)4O],
Ph3Sn[SOCNC4H4], Ph3Sn[S2CO(i-Pr)], and Ph3Sn[S2P(OEt)2]
where the smaller S-Sn-C angles were 95.7(1), 98.2(1),
100.0(1), and 100.09(1)°, respectively, (9, 8, 7, 12). The
three Sn—C distances, ranging from 2.10(1) to 2.12(1) in 1
and 2.13(3) Å (average) in 2, are among the shorter reported
for the four triphenyltin derivatives mentioned above which
range from 2.123(3) to 2.149(5) Å, and similar to that in the
cyclic dithiophosphate derivative, Ph3Sn[S2POCMe2CMe2O]
(19) (2.106(8) to 2.134(9) Å).
The Sn—S bond lengths of 2.444(4) in 1 and 2.44(3) Å
(average) in 2 are similar to those in Ph3Sn[SCO2N(CH2)4O]
(2.446(2) Å), Ph3Sn[S2CO(i-Pr)] (2.445(1) Å), Ph3Sn[SOCNC4H4]
(2.453(1) Å), Ph3Sn[S2P(OEt)2] (2.4582(9) Å), and
Ph3Sn[S2POCMe2CMe2O] (2.436(3) Å); all of which have
been described as containing monodentate ligands. Bidentate
ligands with essentially identical Sn—S bonds, for example
Ph2Sn[S2P(O(i-Pr)2]2 (10) (2.689 (1) and 2.678 (1) Å), are
appreciably longer than the 2.444 (4) Å found in 1. These
bidentate ligands have a partial Pauling bond order of ca.
0.50 compared to the Sn—S bonds in 1 and 2 with bond or-
ders of ca. 0.91. However, examples of bidentate ligands
with more variance in Sn—S bond lengths, also referred to
as unsymmetrical or anisobidentate, are exemplified by
BuSn[S2CN(Et)2]3 (11), where Sn—S bonds range from
2.619(7) to 2.860(6) Å, and Ph2SnCl[S2CO(i-Pr)]2 (20), where
a range of 2.5 to 2.8 Å is quoted. These have bond orders
ranging from ca. 0.78 to 0.32. In Sn[S2COEt]4 (21), two
types of Sn—S distances are reported: those in bidentate lig-
ands ranging from 2.562(2) to 2.627(2) Å) and those in
monodentate ligands being 2.494 (2) Å. However, the sec-
ond sulfur atoms in the latter cases are 2.916(10) Å from tin,
giving an Sn—S distance that is only marginally longer than
in species where the ligands are described as unsymmetrical
bidentate ligands. Given that wave functions are continuous,
it is reasonable to assume ever weakening partial bonds as
the Sn—S distances increase. Our simplistic calculations
based on Pauling’s method (15) gave partial bond orders of
0.80 to 0.28 for Sn—S distances of 2.49–2.92 Å.
1
The H NMR spectra of compounds 1–5 confirm that the
products are over 98% pure relative to any hydrogen-
containing impurities and integration ratios are as expected.
The signals due to the phenyl groups in compounds 1 and 2
(two sets of peaks between 7.40 and 7.68 ppm) are very sim-
ilar in appearance and position to those of the analogous
germanium derivatives (two sets of peaks between 7.36 and
7.64 ppm) (4). The monothiocarbonate ligands give the ex-
pected first order spectra with chemical shifts comparable to
those of the corresponding salts. As observed for the corre-
sponding OCHn-groups in the germanium analogues, the
chemical shifts of hydrogen atoms on the carbon atom at-
tached to oxygen are similar for a given monothiocarbonate
regardless of the number of phenyl groups attached to tin
(4.88 ppm for Ph3Sn[SCO2CH(CH3)2] (2) and 4.86 ppm for
Ph2Sn[SCO2CH(CH3)2]2 (3). In Ph2SnCl[SCO2CH(CH3)2]
(4), the chemical shifts for the protons in both phenyl and
ligand groups are slightly downfield compared to the bis
compound, 3, which is consistent with the electronegativity
of Cl being slightly larger than that of the monothio-
carbonate group. In Me3Sn[SCO2Me] (5) the CH3 chemical
shift of the methyl group attached to tin is also very close to
the value in Me3Ge[SCO2Me] (0.57 ppm). The similarity of
all of the spectra is indicative that the environments of the
monothiocarbonate groups in solution are identical in all
compounds. In the 13C NMR spectra, the chemical shifts of
monothiocarbonate groups are similar regardless of whether
methyl or phenyl groups are attached to tin or the number of
such groups, again as was observed in the analogous germa-
nium derivatives. For the carbon atom in the SCO2 groups,
the chemical shifts range from 170.28 to 172.67 ppm for all
compounds except for 4; again reflecting the presence of the
more electronegative Cl atom. The similar values of the 13C
NMR chemical shifts in the monothiocarbonate ligands is
again consistent with the presence of similar monothiocar-
bonate linkages in solution.
In the absence of a second sulfur atom, the terminal O
atom in both 1 and 2 is oriented towards tin; the Sn—O dis-
tances of 3.040(8) and 3.05(1) Å (average) in 1 and 2, re-
spectively being significantly less than the sum of the van
der Waals radii of 3.57 Å. In Fig. 3 and Table 4, the core
about tin is shown with the inclusion of the Sn—O bond in the
coordination sphere. Similarly, in Ph3Sn[S2CO(i-Pr)] the O
atom of the propoxy group, rather than the terminal S atom
as is normally the case, is oriented toward tin, and it was
proposed that the Sn—O distance of 2.950(3) Å was
sufficiently shorter than the sum of the Van der Waals radii
The crystal structures of Ph3Sn[SCO2Me] (1) and
Ph3Sn[SCO2(i-Pr)] (2)
Both Ph3Sn[SCO2Me] (1) and Ph3Sn[SCO2(i-Pr)] (2)
crystallize in the space group P1 (No. 2), but with two inde-
pendent molecules in the asymmetric unit for 2. The ORTEP
diagrams in Figs. 1 and 2 illustrate that the immediate envi-
ronments about tin in both Ph3Sn[SCO2Me] (1) and
Ph3Sn[SCO2(i-Pr)] (2) are that of a distorted tetrahedron. As
was found for the analogous germanium derivatives,
© 2000 NRC Canada

1220
Can. J. Chem. Vol. 78, 2000
Table 4. Interatomic distances (Å) and angles (°) around M involving the M–O interaction in Ph3Sn[SCO2Me] (1)a 2Ph3Sn[SCO2(i-Pr)]
(2)b Ph3Sn[SCON(CH2)4O],c and Ph3Ge[SCO2Me]b,d
.
Ph3Sn[SCO2Me] (1)
2Ph3Sn[SCO2(i-Pr)] (2)
Ph3Sn[SCON(CH2)4O]
Ph3Ge[SCO2Me]
Sn(1)—S(1)
Sn(1)—O(1)
Sn(1)—C(3)
Sn(1)—C(9)
Sn(1)—C(15)
O(1)-Sn(1)-C(15)
O(1)-Sn(1)-C(9)
O(1)-Sn(1)-C(3)
O(1)-Sn(1)-S(1)
2.444(4)
3.040(8)
2.10(1)
2.12(1)
2.12(1)
2.44(3)
3.05(2)
2.12(1)
2.14(3)
2.12(6)
157.1(6)
83.7(8)
79.5(21)
56.2(3)
2.446(2)
2.809(2)
2.127(5)
2.127(5)
2.149(5)
153.8(1)
86.6(1)
2.253(3)
3.112(7)
1.931(9)
1.946(9)
1.950(9)
155.5(3)
89.0(3)
153.4(4)
86.0(3)
79.6(3)
56.2(2)
80.7(1)
59.8(9)
75.4(3)
56.4(1)
aThe atom numbering is that used for Ph3Sn[SCO2Me].
bThe average of the corresponding bonds and angles for the two molecules in the asymmetric unit.
cRef. (9).
dRef. (4).
to indicate a significant degree of interaction between the Sn
and O atoms (7). Hence the environment around tin can be
described as a distorted trigonal bipyramid. By contrast, in a
study of organotin(IV)1-pyrrolecarbothioates (8) Sn—O dis-
tances ranging from 2.424(3) to 2.523(2) Å were considered
bonding, while those from 2.65 to 3.242 Å were described
as non-bonding (8), as was the distance of 2.809(4) Å in
Ph3Sn[SCOCN(CH2)4O] (9). As discussed above for Sn—S
partial bonds, it is reasonable to simply assume that the par-
tial bonds get weaker as the Sn—O distance gets longer.
Thus, Sn—O distances of 2.424(3) to 2.523(2) can be as-
signed partial bond orders of 0.46 to 0.35 and those from
2.65 to 3.242 bond orders from 0.24 to 0.05. This is essen-
tially a spherical model therefore the bond orders are probably
underestimated. The Sn—O distance in Ph3Sn[SCO2Me] (1)
of 3.040(8) Å corresponds to a bond order of 0.08 to com-
plement the Sn—S bond length of 2.444(4) Å with a bond
order of 0.91. The corresponding Ge—O distance in
Ph3Ge[SCO2Me] (3.112(7) Å) can be assigned a bond order
of only 0.03, compared with a bond order for the Ge—S
bond (2.253(3) Å) of 1.02, so on a relative scale the interac-
tion with the terminal C=O bond is less significant for ger-
manium. The comparative features presented in Table 4 for
Ph3Sn[SCO2Me] (1), Ph3Sn[SCO2(i-Pr)] (2), Ph3Sn[SCON(CH2)4O],
and Ph3Ge[SCO2Me] show striking similarities. Quite
clearly, each molecule has one O-Sn-C angle much closer to
180° (153.4(4) to 157.1(6)°) and the other two much closer
to 90° (75.4 to 89.0°) as expected for distortion based on the
trigonal bipyramid.
The terminal C=O bond length of 1.20(1) Å in 1 is similar
to that in Ph2Te[SCO2(i-Pr)]2 (1.203(9) Å), where the ligand
was considered to be anisobidentate (4). The SC—O bond of
1.34(1) is significantly shorter than the SCO—C bond of
1.43(1) Å. The shortening of the SC—O bond relative to the
SCO—C bond is also clear in 2, despite the poorer refine-
ment, and is consistent with the π-bond character being only
of significance within the planar SCO2 core. The angles in
the planar core (e.g., O=C-O (126(1)°), O=C-O (125(1)° and
O-C-S 109.2° for 1) indicate that the C=O bond is clearly
most strongly involved in the delocalized π-bonding, as was
found for the organogermanium- and organotellurium-
monothiocarbonates (3,4). The SnS—C distance of 1.76(1)
Å for 1, which is marginally shorter than the sum of the co-
valent radii of S and C is also essentially the same as in the
Ge and Te analogues, close to the value found in
Ph3Sn[S2CO(i-Pr)] (1.748(5) Å), and longer than the typical
value (ca. 1.70 Å) for a symmetrical bidentate dithiocar-
bonate.
Infrared and Raman spectra
In general, monothiocarbonates appear to be relatively
poor scatterers and the quality of the Raman spectra is such
that no attempt is made at extensive assignments. However,
the assignment of distinctive characteristic features is possi-
ble by using the same factors described for the analogous
germanium (4) and tellurium (3) derivatives, along with
comparisons with other related dithioacid tin species (6, 21),
and these are provided in linear form for each compound in
the experimental section. There is a marked similarity be-
tween the spectra of Ph2Sn[SCO2(i-Pr)]2 (3) and
Ph2Te[SCO2(i-Pr)]2 (3) which is consistent with the similar
atomic masses of tin and tellurium and with the similar ori-
entations of the monothiocarbonate groups despite the differ-
ences in overall structure. While it is reasonable to assume
that there will be significant coupling between the four
stretching vibrations of the SCO2C unit, the positions of the
three peaks that dominate the infrared spectra in the 1700–
1000 cm–1 region suggest these arise primarily from the
stretching of the three C—O bonds. Thus, for example, in
Ph2Sn[SCO2(i-Pr)]2 (3) the three very strong broad peaks are
seen at 1642 (mainly C=O stretching), 1176 (mainly C—O
stretching), and 1091 cm–1 (mainly O—CH(CH3)2 stretching);
compared with 1653, 1149, and 1088 cm–1 in Ph2Te[SCO2(i-Pr)]2
and 1698, 1159, and 1087 cm–1 in Ph2Ge[SCO2(i-Pr)]2. The
strong band corresponding to that at 1640 cm–1 is observed
at lower wave-number, between 1550 and 1614 cm–1, in
NaSCO2R salts (4), which is consistent with the presence of
a strong terminal C=O bond in the monothiocarbonate deriv-
atives. Any association with the metal is apparently similar
for tin and titanium and least significant for germanium, as
shown by the bond orders calculated for the structures of
Ph3Sn[SCO2Me] (1) in which the band is seen at 1669 cm–1
and that of Ph3Ge[SCO2Me] in which it is at 1695 cm–1. The
fourth stretching vibration associated with the SCO2C core,
which is presumably primarily ν(SnS-C), is seen between
655 and 662 cm–1 as a weaker feature in the infrared and
© 2000 NRC Canada

Drake and Yang
1221
fairly strong feature in the Raman effect. This is within the
expected region for a C—S single bond stretch and is at
lower wave number than in the salts where the C—S bond
would have more partial π-bond character. Two distinctive
peaks seen in 1–4 within the ranges 813–848 and 412–
418 cm–1 can be assigned to the out-of-plane mode,
π(SCO2), and to one of the in-plane bends, δ(SCO2), which
were similarly assigned in the tellurium derivatives to ca.
848 and 416 cm–1. The assignment of π(CO3) in a variety of
carbonate salts is in the region of 830–873 cm–1 suggesting
that the π-electron delocalization is similar in all of these
planar groups. In 5, the feature attributable to π(SCO2) is ob-
scured by the very intense and typical peaks assignable to
the CH3 rocking modes of the methyl groups attached to tin.
In the phenyltin derivatives (1–4) the characteristic and
very distinctive f-phenyl and v-phenyl modes, which are both
of similar intensity, are observed at ca. 736 and 695 cm–1,
along with y-phenyl at ca. 447 cm–1; all three features being
essentially the same in the tellurium and germanium ana-
logues (3, 4). In Me3Sn[SCO2Me] (5) two peaks are seen at
532 and 506 cm–1, which are not seen in the spectra of the
phenyltin derivatives. These clearly correspond to the asym-
metric and symmetric Sn—C stretching vibrations at almost
identical positions to those in Me3SnSMe (531 and 509 cm–1)
(22) suggesting very similar environments about Sn in 5 and
the simple sulfide. In the latter, ν(Sn-S) is seen at 341 cm–1
but generally for dithioacid derivatives it is assigned at
higher wave-number as exemplified by the range 356–
394 cm–1 for a variety of tin dithiocarbamate derivatives
(23). In organotin chlorides, the Sn—Cl stretching vibrations
have been typically assigned to the 344–360 cm–1 region as
they were in a detailed examination of low frequency vibra-
tional spectra of group 14 phenyl compounds including
Ph3SnCl and Ph2SnCl2 (24). By contrast, in mixed halide
ligand derivatives such as Me2SnCl[S2CNMe2], ν(SnCl)
is assigned at a much lower wave-number, 268 cm–1. This
was the basis of our assignment of the low frequency modes
in 4.
Acknowledgement
We wish to thank the Natural Sciences and Engineering
Research Council of Canada for financial support.
References
1. K.K. Pandey and H.L. Wingan. Rev. Inorg. Chem. 6, 71
(1984); S. Datta and H.L. Agarwala. Indian J. Chem. Sect. A:
Inorg. Bio-inorg. Phys. Theor. Anal. 20A, 1190 (1981); T.V.
Ashworth, M. Nolte, and E. Singleton. J. Organomet. Chem.
121, C57 (1976); T.R. Gaffney and J.A. Ibers. Inorg. Chem.
21, 2860 (1982); N. Sonoda and T. Tanaja. Inorg. Chim. Acta,
12, 261 (1975).
2. E.E. Reid. Organic chemistry of bivalent sulfur. Vol. IV.
Chemical Publishing, N.Y. 1962, and references therein.
3. J.E. Drake, R.J. Drake, A.G. Mislankar, R. Ratnani, and J.
Yang. Can. J. Chem. 74, 1968 (1996).
4. J.E. Drake and J. Yang. Can. J. Chem. 76, 319 (1998).
5. E.M. Holt, F.A.K. Nasser, A.Wilson, Jr., and J.J. Zuckerman.
Organometallics, 4 2073 (1985).
6. S.W. Cowan, R.W. Gable, B.F. Hoskins, and G. Winter. Inorg.
Chim. Acta, 77, L225 (1983); R.W. Gable, C.L. Raston, G.L.
Rowbottom, A.H. White, and G. Winter. J. Chem. Soc. Dalton
Trans. 203, (1981); D. Dakterniks, B.F. Hoskins, E.R.T.
Tiekink, and G. Winter. Inorg. Chim. Acta, 85, 215 (1984).
7. E.R.T. Tiekink and G. Winter. J. Organomet. Chem. 314, 85
(1986).
8. D.K. Srivastave, V.D. Gupta, H. Noth, and W. Rattay. J. Chem.
Soc. Dalton Trans. 1533, (1988).
9. S. Chandra, B.D. James, R.J. Magee, W.C. Patalinghug, B.W.
Skelton, and A.H. White. J. Organomet. Chem. 346, 7 (1988).
10. K.C. Molloy, M.B. Hossain, D. Van der Helm, J.J. Zuckerman,
and I. Haiduc. Inorg. Chem. 9, 2041 (1980).
11. J.S. Morris and E.O. Schlemper. J. Cryst. Mol. Struct. 9, 1
(1979).
12. K.C. Molloy, M.B. Hossain, D. Van der Helm, J.J. Zuckerman,
and I. Haiduc. Inorg. Chem. 9, 3507 (1979).
13. G.M. Sheldrick. Acta Crystallogr. Sect. A: Cryst. Phys. Diffr.
Theor. Gen. Crystallogr. A46, 467 (1990).
Concluding comments
14. TEXSAN-TEXRAY structure analysis package. Molecular
Structure Corp., Woodlands, Tex. 1985 and 1992.
15. L. Pauling. J. Am. Chem. Soc. 69, 542 (1947); The nature of
the chemical bond. 3rd ed. Cornell University Press, Ithaca,
New York. 1960.
16. A.F. Wells. Structural inorganic chemistry. 4th ed. Clarendon
Press, Oxford. 1975.
17. A. Bondi. J. Phys. Chem. 68, 441 (1964); L. Pauling. The na-
ture of the chemical bond. 3rd ed. Cornell University Press,
Ithaca, New York. 1960.
18. I.D. Brown. J. Solid State Chem. 11, 214 (1974).
19. H. Preut, V.D. Ngo, and F. Huber. Acta Crystallogr. Sect. C:
Cryst. Struct. Commun. C43, 164 (1987).
20. D. Dakterniks, B.F. Hoskins, P.A. Jackson, E.R.T. Tiekink, and
G. Winter. Inorg. Chim. Acta, 101, 203 (1985).
21. C.L. Raston, P.R. Tennant, A.H. White, and G. Winter. Aust. J.
Chem. 31, 1493 (1978).
22. D.F. van de Vondel, E.V. van den Berghe, and G.P. van de
Kelen. J. Organomet. Chem. 23, 105 (1970).
The isolation of organotin monothiocarbonates proved to
be more difficult than for the corresponding organogerman-
ium derivatives. The X-ray structures of Ph3Sn[SCO2Me] (1)
and Ph3Sn[SCO2(i-Pr)] (2) demonstrate a preference for the
orientation of the terminal C=O oxygen atom towards tin, at
least in the solid state. The resulting weak intermolecular in-
teraction indicates an anisobidentate link that is relatively
more significant than in the corresponding germanium deriv-
ative. Thus the distortions from “all-tetrahedral” angles around
tin are consistent with the formation of a weak Sn—O link
that gives a distorted trigonal bipyramidal arrangement
around tin. In dithio derivatives, there is often a tendency for
Ph3SnL species with symmetrical bidentate ligands to dis-
proportionate to the bis species, Ph2SnL2 on recrystallization
giving rise to a trans octahedral structure. This clearly is not
the case for Ph3Sn[SCO2Me] and Ph3Sn[SCO2(i-Pr)] and in-
deed we were not able to isolate X-ray quality crystals for
Ph2Sn[SCO2Me]2 or Ph2Sn[SCO2(i-Pr)]2; consistent with the
ligands being essentially monodentate in solution as is indi-
cated by the NMR spectra.
23. M. Honda, M. Komura, Y. Kawasaki, T. Tanaka, and R.
Okawara. J. Inorg. Nucl. Chem. 30, 3231 (1968).
24. A. Smith. Spectrochim. Acta Part A, 24A, 695 (1968).
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