New organotin xanthates R2Sn(S2COR′)2 and R3SnS2COR′ (R = Me, Ph and R = Me, CH2Ph). Molecular structure of BIS(O-methyl-Dithiocarbonato)-Diphenyltin(IV), Ph2Sn(S2COMe

Full text of DOI:10.1081/SIM-100104845

Synthesis and Reactivity in Inorganic and Metal-Organic
Chemistry
ISSN: 0094-5714 (Print) 1532-2440 (Online) Journal homepage: http://www.tandfonline.com/loi/lsrt19
NEW ORGANOTIN XANTHATES R2Sn(S2COR′)2
AND R3SnS2COR′ (R = Me, Ph and R = Me,
CH2Ph). MOLECULAR STRUCTURE OF BIS(O-
METHYL-DITHIOCARBONATO)-DIPHENYLTIN(IV),
Ph2Sn(S2COMe)2
Jose S. Casas , Alfonso Castineiras , Ionel Haiduc , Agustin Sánchez , Radu F.
Semeniuc & Jose Sordo
To cite this article: Jose S. Casas , Alfonso Castineiras , Ionel Haiduc , Agustin Sánchez ,
Radu F. Semeniuc & Jose Sordo (2001) NEW ORGANOTIN XANTHATES R2Sn(S2COR′)2
AND R3SnS2COR′ (R = Me, Ph and R = Me, CH2Ph). MOLECULAR STRUCTURE OF BIS(O-
METHYL-DITHIOCARBONATO)-DIPHENYLTIN(IV), Ph2Sn(S2COMe)2 , Synthesis and Reactivity
in Inorganic and Metal-Organic Chemistry, 31:5, 725-736, DOI: 10.1081/SIM-100104845
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Date: 24 August 2017, At: 14:43

SYNTH. REACT. INORG. MET.-ORG. CHEM., 31(5), 725–736(2001)
NEW ORGANOTIN XANTHATES
R2Sn(S2COR0)2 AND R3SnS2COR0 (R ¼ Me,
Ph and R ¼ Me, CH2Ph). MOLECULAR
STRUCTURE OF BIS(O-METHYL-
DITHIOCARBONATO)-DIPHENYLTIN(IV),
Ph2Sn(S2COMe)2
Jose S. Casas,a Alfonso Castineiras,a Ionel Haiduc,b,*
Agustin Sanchez,a Radu F. Semeniuc,b and Jose Sordoa
aDepartamento de Quimica Inorganica, Facultade de
Farmacia, Universidade de Santiago de Compostela,
E-15706Santiago de Compostela, Galicia, Spain
bFacultatea de Chimie, Universitatea ‘‘Babes-Bolyai,’’
RO-3400, Cluj-Napoca, Romania
ABSTRACT
Five new organotin xanthates with general formula
R2Sn(S2COR0)2 and R3SnS2COR0 (R ¼ Me and Ph and
R0 ¼ Me and CH2Ph) were prepared and characterized by
elemental analyses, IR and NMR spectra. The crystal and
molecular structure of was determined by X-ray diffraction.
The compound Ph2Sn(S2COMe)2, M ¼ 487.22 is triclinic,
P1, with unit cell dimensions a ¼ 9.0265(14) A, b ¼ 9.395(2) A,
*Corresponding author. E-mail: ihaiduc@chem.ubbcluj.ro
725
Copyright # 2001 by Marcel Dekker, Inc.
www.dekker.com

726
CASAS ET AL.
c ¼ 11.989(2) A, a ¼ 100.919(17)ꢀ, b ¼ 96.55(2)ꢀ, g ¼ 97.576ꢀ.
The tin atom is coordinated by two asymmetrically chela-
ting xanthate ligands [Sn-S(11) ¼ 2.4975(11) A, Sn-S(12) ¼
3.0404(12) A, Sn-S(21) ¼ 2.4938(11) A, Sn-S(22) ¼ 3.1266(12)
A] and by two phenyl groups.
INTRODUCTION
The xanthate (alkyldithiocarbonate) ion, ROCSÀ2 , displays a wide
variety of coordination patterns, which have been reviewed1,2. Solid-state
structures studies of a number of organometallic xanthates show that in the
case of monometallic, monoconnective (monodentate) coordination of the
xanthate moiety, there are two possible variations. The non-bonded sulfur
atom can be twisted towards the central atom (the S,S mode) or the oxygen
atom can be twisted towards the central atom (the S,O mode).
In both cases there is some interaction between the sulfur or oxygen
atom from the xanthate ligand with the central atom. It was suggested, on
the basis of structural studies of gold(I) xanthates3, that these orientations
are related with the nature of other metal substituents. The presence of
bulky ligands around the central atom favours the S,S mode and the lack of
bulky substituents favours the S,O mode.
Organotin xanthates usually adopt the S,S mode. This is the case
4
5
6
for Me2SnðS2COEtÞ2; Me2SnðS2COC6H11Þ2; Ph2SnðS2COEtÞ2 and Ph2Sn
7
ðS2COPr-iÞ2. The S,O mode of coordination is much rarer, and is known only
in two compounds, namely Ph3SnS2COPr-i8 and Ph3SnS2COCH2CH2OMe9.
This means that the coordination pattern is determined not only by the
substituents around tin atom and suggests that the structural behavior of the
xanthate ligand depends on the Lewis acidity of the central atom7.

NEW ORGANOTIN XANTHATES
727
In an attempt to understand the structural behavior of the xanthate
ligand relative to the tin coordination center, we report five new organotin
xanthates of the general formulae R2Sn(S2COR0)2 and R3SnS2COR0, where
R ¼ Me and Ph and R0 ¼ Me and CH2Ph and the crystal and molecular
structure of Ph2Sn(S2COMe)2.
RESULTS AND DISCUSSION
Preparation of the Compounds
The organotin xanthates R2Sn(S2COMe)2, R2Sn(S2COCH2Ph)2,
R3SnS2COMe and R3SnS2COCH2Ph (R ¼ Me or Ph) were prepared via the
metathetical reaction between organotin dihalides or monohalides and
the appropriate sodium or potassium xanthates, according to equations (1)
and (2).
R2SnCl2 þ 2MS2COR0 ! R2SnðS2COR0Þ2 þ 2MCl
R3SnCl þ MS2COR0 ! R3SnS2COR0 þ MCl
ð1Þ
ð2Þ
The combination ratio is R2Sn:L ¼ 1:2 for all diorganotin compounds
and R3Sn:L ¼ 1:1 for all triorganotin compounds (L ¼ xanthate). All com-
pounds are colorless crystalline solids. Decomposition was observed for
diorganotin xanthates R2SnL2 on heating. Triphenyltin xanthates melt
without decomposition. The yields, melting points and elemental analysis
data are listed in Table I.
Infrared Spectra
The IR spectra were recorded for all of the new organotin complexes.
The regions of interest are around 1200, 1000 and 400 cmÀ1, where C-O, C-S
and M-S stretching frequencies, characteristic for the xanthate moiety, are
located. Although the stretchings of the group -O-C(S)SÀ appear in more
than these three domains, attempts to interpret in detail the infrared spectra
were of limited success, because most of the bands are combinations of
several vibrations1.
In the case of dimethyltin xanthates, bands assigned to n(C-Sn-C)
vibrations can be observed in the expected region of 6507550 cmÀ1
.
The values of the most important absorption bands are presented in
Table II.

Table I. Elemental Analyses of the Synthesised Compounds
Elemental Analyses
C
H
S
Empirical Formula
and Formula Weight
Yield
(%)
M.p.
(ꢀC)
Compound
Calc. Found Calc. Found Calc. Found
Me2Sn(S2COMe)2 C6H12O2S4Sn FW: 363.1
Me2Sn(S2CCOCH2Ph)2 C18H20O2S4Sn FW: 515.3
95.8
58.2
83.7
72.2
46.9
11072 (dec) 19.85
15375 (dec) 41.9641.22
11576(dec) 39.44 39.41
52.53
58.5657.71
19.75
3.33
3.91
3.31
3.97
4.16 4.27
2.90
4.29
35.32
7
26.32
14.03
7
35.91
7
25.73
14.48
7
Ph2Sn(S2COMe)2
Ph3SnS2COMe
Ph3SnS2CCOCH2Ph
C16H16O2S4Sn FW: 487.3
C20H18OS2Sn FW: 457.2
C26H22OS2Sn FW: 533.3
2.85
4.02
9173
8375
52.54

NEW ORGANOTIN XANTHATES
729
Table II. Selected Infrared Data (cmÀ1) of Organotin Compoundsa
Compound
n(C-O)
n(C-S)
n(C-Sn-C)
n(Sn-S)
Me2Sn(S2COMe)2
1246s 1207 s
1172 m
1071 s 1050 s
640 w 556 m 470 m 457 s
Me2Sn(S2COCH2Ph)2 1225 s 1214 s
1200 s 1190 s
1056s 997 m
614 w 587 w
560 m
449 m 430 m
458 s 448 s
Ph2Sn(S2COMe)2
1218 s
1049 s 1019 m
996m
1060 s 1020 m
7
Ph3SnS2COMe
Ph3SnS2COCH2Ph
1221 s
7
7
450 s 440 s
454 s 445 m
1223 m 1189 s 1044 s 996m
as ¼ strong, m ¼ medium, w ¼ weak.
1H NMR Spectra
1
The H NMR spectra recorded in CDCl3 solution show the expected
bands for the Sn-CH3, Sn-C6H5, O-CH3 and O-CH2-C6H5 groups with the
right integrated area ratios. The chemical shifts are as follows:
Me2SnðS2COMeÞ2
d ¼ 1:46s ðSn-CH3Þ; 4:11 s ðO-CH3Þ
Me2SnðS2COCH2PhÞ2 d ¼ 1:44 s ðSn-CH3Þ; 5:47 s ðO-CH2Þ;
7:3777:6 0 m ðC6H5Þ
Ph2SnðS2COMeÞ2
d ¼ 3:95 s ðO-CH3Þ; 7:477:9 m ðC6H5Þ
d ¼ 5:26s ðOCH2Þ; 7:277:6 m ðC6H5Þ
Ph3SnðS2COCH2PhÞ
1
The H NMR spectra are straightforward and display no unusual
features.
X-Ray Data Collection and Reduction
A colorless prismatic crystal of Ph2Sn(S2COMe)2 was grown by slow
evaporation of a dichloromethane solution of the compound and the crystal
was mounted on a glass fiber and used for data collection. Cell constants and
an orientation matrix for data collection were obtained by least-squares
REFinement of the diffraction data from 25 reflections in the range
of 9.295ꢀ < y < 20.832ꢀ on an Enraf Nonius MACH3 automatic dif-
fractometer10. Data were collected at 293 K using MoKa radiation
(¼ 0.71073 A) and the o scan technique and were corrected for Lorentz and
polarization effects11. A semiempirical absorption correction (c scan) was
made12.

730
CASAS ET AL.
Structure Solution and Refinement
The structure was solved by direct methods13 which revealed the
position of all non-hydrogen atoms, and refined on F2 by a full-matrix
least-squares procedure using anisotropic displacement parameters14. All
hydrogen atoms were located from difference Fourier maps except those
of the methyl groups which were located in their calculated positions
(C-H ¼ 0.96A ). The located H atoms were refined isotropically, whereas
the calculated H atoms were refined using a riding model. Atomic
scattering factors are from the ‘‘International Tables for X-ray Cryst-
allography’’15. For molecular graphics the program PLATON97 was used16.
A summary of the crystal data, experimental details and Refinement results
are listed in Table III.
Table III. Crystal Data and Structure Refinement for Ph2Sn(S2COMe)2
Compound
(C6H5)2Sn(S2COCH3)2
C16H16O2S4Sn
487.22
293(2) K
0.71073 A
Empirical formula
Formula weight
Temperature
Wave length
Crystal system, space group
Unit cell dimensions
Triclinic, P1
a ¼ 9.0265(14) A a ¼ 100.919(17)ꢀ
b ¼ 9.395(2) A
b ¼ 96.55(2)ꢀ
c ¼ 11.989(2) A g ¼ 97.576(18)ꢀ
Volume
979.4(3) A3
Z, Calculated density
Absorption coefficient
F(000)
2, 1.652 Mg=m3
1.735 mmÀ1
484
Crystal size
y range for data collection
Index ranges
0.30 Â 0.30 Â 0.20 mm
2.68 to 27.98ꢀ
À11 ꢁ h ꢁ 0; À12 ꢁ k ꢁ 12; À15 ꢁ l ꢁ 15.
5001=4707= [R(int) ¼ 0.0251]
27.98799.8%
c scan
0.978 and 0.794
Full-matrix least-squares on F2
4707=0=250
1.036
R1 ¼ 0.0339, wR2 ¼ 0.0634
R1 ¼ 0.0773, wR2 ¼ 0.0729
0.554 and À0.543 e AÀ3
Reflections collected=unique
Completeness to 2y
Absorbtion correction
Max. and min. transmission
Refinement method
Data=restraints=parameters
Goodness-of-fit on F2
Final R indices [I > 2s(I)]
R indices (all data)
Largest diff. peak and hole

NEW ORGANOTIN XANTHATES
Description of Structure
731
The molecular structure of Ph2Sn(S2COMe)2 is shown in Fig. 1.
Selected bond lengths and angles are listed in Table IV. There are no
intermolecular interactions and the crystal structure consists of discrete
molecules. The tin atom is coordinated by two asymmetrically
chelating xanthate ligands and by two phenyl groups. There are two
short Sn-S distances (primary bonds), Sn-S(11) ¼ 2.4975(11) A and
Sn-S(21) ¼ 2.4938(11) A and two long Sn-S distances (secondary bonds),
Sn-S(12) ¼ 3.0404(12) A and Sn-S(22) ¼ 3.1266(12) A.
The coordination geometry of the tin atom is distorted tetrahedral if
only the Sn-C and primary Sn-S bonds are considered. If the secondary Sn-S
bonds are taken into account, the coordination polyhedron around tin is a
bicapped tetrahedron, with the S(12) and S(22) atoms above two triangular
faces. In any case, the geometry is distorted, as suggested by the bond
angles, e.g. C(11)-Sn-C(21) ¼ 134.06(14)ꢀ, which in a regular octahedral
geometry with axial phenyl groups would be 180ꢀ and in regular tetrahedral
geometry it would be close to 109ꢀ. The four sulfur atoms from the xanthate
ligand define a trapezoidal plane in an arrangement similar to that found in
other diorganotin compounds with thio ligands6,7
.
Figure 1. Molecular structure and crystallographic numbering scheme for
Ph2Sn(S2COMe)2.

732
CASAS ET AL.
The asymmetry of the xanthate ligand is reflected in the corre-
sponding C-S bond distances. As expected, the C-S bond lengths for the
sulphur atom bonded strongly to tin atom are longer than C-S bond lengths
which involve the weaker bonded sulphur atom to tin. As shown
in Table IV, the bond lengths are: C(1)-S(11) ¼ 1.729(4) A and C(1)-
S(12) ¼ 1.645(4) A for the C(1) xanthate ligand, and C(2)-S(21) ¼ 1.733(4) A
and C(2)-S(22) ¼ 1.650(4) A for the C(2) xanthate ligand.
An unexpected result appears when the differences between Sn-S and
C-S bonds lengths are calculated in diorganotin dixanthates. It has been
suggested7 that the degree of asymmetry in the coordination pattern of the
xanthate ligand is correlated with dSn-S and dC-S (where d is the difference
between the long and the short Sn-S and C-S bonds, respectively, within a
coordinated xanthate ligand). Furthermore, the DSn-S values (where DSn-S
is the average of differences between the long and the short Sn-S bonds
formed by the two different xanthate ligands) are correlated with the che-
lating ability of the xanthate ligand6.
In Table V are compared some selected bonds and angles for
Ph2Sn(S2COMe)2 and two other diphenyltin xanthates, Ph2Sn(S2COEt)2 and
Ph2Sn(S2COPr-i)2 and in Table VI are listed the values of dSn-S, dC-S and DSn-S
for the same compounds. In the case of Ph2Sn(S2COEt)2 dSn-S and dC-S values
are 0.736A and 0.109 A, respectively, for one xanthate ligand and 0.566 A
and 0.091 A for the other. For Ph2Sn(S2COPr-i)2 the values are 0.567 A and
Table IV. Selected Bond Lengths (A) and Angles (deg.) for Ph2Sn(S2COMe)2
Atoms
Distance
Atoms
Distance
Sn-S(11)
Sn-S(12)
C(1)-S(11)
C(1)-S(12)
C(1)-O(1)
Sn-C(11)
2.4975(11)
3.0404(12)
1.729(4)
1.645(4)
1.326(4)
2.128(3)
Sn-S(21)
Sn-S(22)
C(2)-S(21)
C(2)-S(22)
C(2)-O(2)
Sn-C(21)
2.4938(11)
3.1266(12)
1.733(4)
1.650(4)
1.315(4)
2.128(3)
Atoms
Angle
Atoms
Angle
105.93(10)
105.64(10)
82.27(9)
82.17(10)
85.63(4)
C(11)-Sn-S(11)
C(21)-Sn-S(11)
C(11)-Sn-S(12)
C(21)-Sn-S(12)
S(11)-Sn-S(12)
S(11)-Sn-S(22)
S(12)-Sn-S(22)
C(11)-Sn-C(21)
108.97(10)
105.91(10)
85.81(10)
83.24(10)
64.31(3)
148.77(3)
146.87(3)
134.06(14)
C(11)-Sn-S(21)
C(21)-Sn-S(21)
C(11)-Sn-S(22)
C(21)-Sn-S(21)
S(11)-Sn-S(21)
S(12)-Sn-S(21)
S(21)-Sn-S(22)
149.94(3)
63.15(3)

NEW ORGANOTIN XANTHATES
Table V. Comparative Bond Lengths (A) and Angles (deg.)a
733
Ph2Sn(S2COMe)2
(this work)
Ph2Sn(S2COEt)2
(Ref. 6)
Ph2Sn(S2COPr-i)2
(Ref. 7)
Atoms
Distance
2.4975(11)
3.0404(12)
2.4938(11)
3.1266(12)
1.729(4)
1.645(4)
1.733(4)
1.650(4)
Angle
134.06(14)
Distance
2.484(1)
3.220(1)
2.486(1)
3.052(1)
1.742(4)
1.633(4)
1.732(4)
1.641(4)
Angle
Distance
2.500(1)
3.067(7)
2.482(1)
3.179(1)
1.733(3)
1.663(3)
1.747(3)
1.652(3)
Angle
Sn-S(11)
Sn-S(12)
Sn-S(21)
Sn-S(22)
C(1)-S(11)
C(1)-S(12)
C(2)-S(21)
C(2)-S(22)
C(11)-Sn-C(21)
126.5(1)
128.6(1)
aThe crystallographic numbering scheme used in original papers was changed to fit
the crystallographic numbering scheme used in this work in Fig. 1.
0.07 A for one xanthate ligand and 0.697 A and 0.095 A for the other. As
expected, the greater dSn-S value corresponds to the greater dC-S value and the
smallest dSn-S value corresponds to the smallest dC-S value and there are major
differences between the two dC-S values for each compound.
In the case of Ph2Sn(S2COMe)2 the two dSn-S values are 0.5429 A and
0.6328 A, but the corresponding dC-S values (0.084 A and 0.083 A) are
practically equal. Although the degrees of asymmetry of the methylxanthate
Table VI. The dSn-S
,
Ph2Sn(S2COEt)2, and Ph2Sn(S2COPr-i)2 (A)
dC-S
,
and DSn-S Valuesa for Ph2Sn(S2COMe)2,
Compound
dSn-S(1)
d
Sn-S(2)
dC-S(1)
d
C-S(2)
ꢀSn-S
Ph2Sn(S2COMe)2
Ph2Sn(S2COEt)2
Ph2Sn(S2COPr-i)2
0.5429
0.736
0.567
0.6328
0.566
0.697
0.084
0.109
0.07
0.083
0.091
0.095
0.5878
0.651
0.632
aExplanatory note: d is the difference between the long and the short bond within a
coordinated xanthate ligand:
Sn-S bonds: dSn-Sð1Þ ¼
d
Sn-Sð12Þ À dSn-Sð11Þ
;
dSn-Sð2Þ ¼ dSn-Sð22Þ À dSn-Sð21Þ
dC-Sð2Þ ¼ dCð2Þ-Sð21Þ À dCð2Þ-Sð22Þ
C-S bonds: dC-Sð1Þ ¼
dCð1Þ-Sð11Þ À dCð1Þ-Sð12Þ
;
DSn-S is the average of the differences between the long and the short Sn-S bonds
formed by the two different xanthate ligands.
DSn À S ¼ ½dSnÀSð1Þ þ dSnÀSð2Þꢂ=2
d ¼ bond length between indicated atoms.

734
CASAS ET AL.
ligands are not equivalent and the difference between the two dSn-S values for
the Ph2Sn(S2COMe)2 are significantly different, this has no effect over the
dC-S bonds lengths.
Furthermore, the DSn-S values (Table VI) for the diphenyltin xan-
thates suggest that the methylxanthate is a better chelating ligand and the
chelating capacity increases in following order:
ÀS2COMe >À S2COPr-i >À S2COEt
in the same order as steric hindrance.
This conclusion is in agreement with the CPh-Sn-CPh angles, the
value of 134.06(14)ꢀ for Ph2Sn(S2COMe)2 being the greater in the series
(Table V), meaning that the two phenyl groups in this compound have
the smallest (although significant) deviation from the linearity and,
obviously, Ph2Sn(S2COMe)2 has the greater symmetry degree around the
tin atom.
EXPERIMENTAL
Reagents and Procedure
The starting materials (Me2SnCl2, Ph2SnCl2 and Ph3SnCl) and
all solvents were commercial products of analytical grade purity and used as
supplied. Sodium methylxanthate and potassium benzylxanthate were pre-
pared from the appropriate alcohol, sodium or potassium hydroxide and
carbon disulpfide, with excess alcohol acting as solvent.
Elemental analysis was performed on a Perkin Elmer 240B apparatus.
Melting points are uncorrected as determined on a Buchi apparatus. IR
spectra were recorded on a Perkin Elmer 1330 spectrometer (KBr pellets).
NMR spectra were recorded in CDCl3 at room temperature on a Bruker
WM-250 spectrometer.
Synthesis of Organotin Xanthates
All the organotin xanthates were prepared by a similar procedure,
as described for dimethyltin methylxanthate, by varying the molar
combination ratio. Yields, melting points and analytical data are given in
Table I.

NEW ORGANOTIN XANTHATES
Dimethyltin Xanthate Me2Sn(S2COMe)2
735
To a solution of Me2SnCl2 (0.220 g, 1 Mmole in 50 mL CH2Cl2) was
added with stirring 0.260 g (2 mmoles) of finely ground NaS2COMe. The
mixture was stirred for one hour. The solution was then filtered and
the volume reduced to 20 mL under vacuum. The slow evaporation of the
remaining solution deposited colorless crystals of Me2Sn(S2COMe)2.
ACKNOWLEDGMENT
We thank the Xunta de Galicia (Spain) [Grant XUGA 20308 B 97]
and the National Council for Academic Research (Romania) [Grant 88
financed by the World Bank] for the financial support of this work.
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736
CASAS ET AL.
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Received: February 22, 2000
Accepted: March 1, 2001
Referee I: M. K. Denk
Referee II: P. Wisian-Neilson