Diorgano(1,3-dithiole-2-one-4,5-dithiolato)tin compounds, R2Sn(dmio) and [Q][R2Sn(dmio)X] [Q = onium cation; R = alkyl or aryl; X = halide or pseudohalide]: Crystal structures of Me2Sn(dmio) and [NEt4][Ph2SnCl(dmio)]

Article abstract of DOI:10.1016/S0022-328X(98)01044-4

Compounds, [Q][R₂SnX(dmio)], [5: (a) Q = NEt₄, R = Et, X = Br: R = Ph, X = Cl, (b) Q = NEt₄, (c) Q = ferrocenyl-CH₂NMe₃], and [R₂Sn(dmio)]_n [6: (a) R = Ph, (b) R = Me, (c) R = Et (d) R = Bu] (dmio = 1,3-dithiole-2-one-4,5-dithiolate), have been prepared from [Q]₂[Zn(dmio)₂] and R₂SnX₂; compounds [5: Q = NEt₄; R = Ph; (d) X = Br, (e) X = I, (f) X = NCS] have been obtained by halide/pseudohalide exchange reactions from the chloride using NaX (X = Br, I or NCS). X-ray crystallography revealed that 6b is six-coordinate in the solid state, as a result of intermolecular Sn-O interactions [Sn-Oⁱ = 2.654(6) A], which link the molecules into chains, and weak Sn-S interactions [Sn-Sⁱⁱ = 3.649(3) A], which link the chains into layers. The anion in ionic 5b, as shown by X-ray crystallography, contains a distorted trigonal bipyramidal tin centre.

Full text of DOI:10.1016/S0022-328X(98)01044-4

Journal of Organometallic Chemistry 577 (1999) 140–149
Diorgano(1,3-dithiole-2-one-4,5-dithiolato)tin compounds, R2Sn(dmio)
and [Q][R2Sn(dmio)X] [Q=onium cation; R=alkyl or aryl; X=halide
or pseudohalide]: crystal structures of Me2Sn(dmio) and
[NEt4][Ph2SnCl(dmio)]
Zahid H. Chohan, R. Alan Howie, James L. Wardell *
Department of Chemistry, Uni6ersity of Aberdeen, Meston Walk, Old Aberdeen, AB24 3UE Scotland, UK
Received 14 September 1998
Abstract
Compounds, [Q][R2SnX(dmio)], [5: (a) Q=NEt4, R=Et, X=Br: R=Ph, X=Cl, (b) Q=NEt4, (c) Q=ferrocenyl–
CH2NMe3], and [R2Sn(dmio)]n [6: (a) R=Ph, (b) R=Me, (c) R=Et (d) R=Bu] (dmio=1,3-dithiole-2-one-4,5-dithiolate), have
been prepared from [Q]2[Zn(dmio)2] and R2SnX2; compounds [5: Q=NEt4; R=Ph; (d) X=Br, (e) X=I, (f) X=NCS] have been
obtained by halide/pseudohalide exchange reactions from the chloride using NaX (X=Br, I or NCS). X-ray crystallography
i
˚
revealed that 6b is six-coordinate in the solid state, as a result of intermolecular Sn–O interactions [Sn–O =2.654(6) A], which
ii
˚
link the molecules into chains, and weak Sn–S interactions [Sn–S =3.649(3) A], which link the chains into layers. The anion in
ionic 5b, as shown by X-ray crystallography, contains a distorted trigonal bipyramidal tin centre. © 1999 Elsevier Science S.A. All
rights reserved.
Keywords: Tin; 1,3-Dithiole-2-one-4,5-dithiolato-; Octahedral; Trigonal bipyramidal
1. Introduction
plexes of the related 1,3-dithiole-2-one-4,5-dithiolato
ligand, dmio (2: C3OS24−)] [8].
Organotin 1,2-dithiolate complexes have featured in
many studies; the ligands used include aliphatic deriva-
tives, e.g. −SCH2CH2S− (edt) [1], −SCH2CHMeS−
[2], alkenyl derivatives, e.g. −SCHꢀCHS− [3],
−SC(CN)ꢀC(CN)S− (mnt) [3,4], aryl derivatives,
−SC6H4S− (bdt) [5] and 3,4-(−S)2C6H3Me (tdt) [1b,c,
2b, 4a, 5b, 6], and heterocyclic derivatives (1: C3S52−
)
[7] and (2: C3OS24−) [8]. Much of the interest has
centred on syntheses and structure determinations, al-
though the uses of the chelates in heterocyclic synthesis
have become of great interest [9,10]. During the last few
years, complexes of the 1,3-dithiole-2-thione-4,5-dithio-
lato ligand, dmit, (1: C3S25−) have attracted particular
attention [7]; less frequently studied have been com-
* Corresponding author. Fax:
j.wardell@abdn.ac.uk.
+44-1224-272921; e-mail:
0022-328X/99/$ - see front matter © 1999 Elsevier Science S.A. All rights reserved.
PII: S0022-328X(98)01044-4

Z.H. Chohan et al. / Journal of Organometallic Chemistry 577 (1999) 140–149
141
Table 1
Crystal data and structure refinement
Compound
Me2Sn(dmio)
[NEt4][Ph2SnCl(dmio)]
Empirical formula
Formula weight
Temperature (K)
C5H6OS4Sn
329.05
298
0.71069
C23H30ClNOS4Sn
604.89
298
0.71069
˚
Wavelength (A)
Crystal system
Space group
Orthorhombic
Pbcn
17.642(9)
7.683(4)
Triclinic
P1
9.456(11)
11.473(15)
˚
a (A)
˚
b (A)
˚
c (A)
15.031(9)
12.476(12)
h (°)
i (°)
k (°)
90
90
90
97.73(9)
87.59(9)
95.90(10)
1333(3)
3
˚
V (A )
2037.4(19)
Z
8
2
Dcalc. (Mg m−3
)
2.145
3.25
0.1211/0.4265
1264
1.507
1.38
None
628
Absorption coefficient (mm−1
Max/min transmission factors
F(000)
)
Crystal size (mm)
0.65×0.6×0.1
0.6×0.36×0.16
Theta range for data collection (°)
Index ranges
Max. 30
05h524
Max. 25
−115h511
05k510
−135k513
05l521
05l514
Reflections collected
Independent reflections
Observed reflections [F\4|(F)]
Rint
Refinement method
Number of parameters
Goodness-of-fit (S)
Final R indices
3404
2656
2055
0.0015
4740
4477
3828
0.001
Full-matrix least-squares on F2
120
Full-matrix least-squares on F2
258
1.31
0.8964
R=0.066 [F\4|(F)]
wR=0.072
R=0.051 [F\4|(F)]
wR=0.055
Final weighting scheme
Residual diffraction
w=1/(|2F+0.007046F2)
w=1/(|2F+0.001791F2)
2.56 (0.92a A from Sn)
˚
1.13 (0.96 A from Sn)
−1.22
˚
Max/min (e A−3
)
−2.62
a
˚
One of four peaks of roughly equal intensity distant 0.77–0.92 A from Sn.
While full reports of the synthesis and structures of
the ionic mono-dmit complexes, (3: Q=cation; X=
halide or pseudohalide) [7b,c] and polymeric species (4:
R=simple alkyl or aryl) [7a] have been published, only
preliminary reports, concentrating on structural as-
pects, have been made on two mono-dmio complexes
(5f: Q=NEt4, X=NCS, R=Ph) and (5a: Q=NEt4,
X=Br, R=Et) [8b,c]. We wish now to report on the
neutral species [6: (a) R=Ph, (b) R=Me, (c) R=Et,
(d) R=Bu] as well as further information on the ionic
complexes (5: Q=NEt4 or ferrocenylCH2NMe3; X=
Cl, Br, I or NCS; R=Et or Ph). Comparisons of the
structures of the related dmio and dmit complexes are
also made.
were obtained on a Bruker 250 MHz instrument. Ten
second pulse delays were utilised in the acquisition of
the 13C-NMR spectra of the dmio compounds. IR
spectra were recorded on Phillips analytical PU900 and
Nicolet 205 Fourier-transform instruments.
Zincate salts, [Q]2[Zn(dmio)2], [Q=NEt4, or ferro-
cenylmethyl(trimethyl)ammonium] were obtained by
published procedures [11,12]; Et2SnBr2, Me2SnCl2,
Bu2SnCl2, and Ph2SnCl2 were obtained from appropri-
ate tetraorganostannanes and stannic halides and had
physical properties in agreement with published values
[13].
2.1. [NEt4][Et2SnBr(dmio)] (5a)
A solution of Et2SnBr2 (0.67 g, 2.0 mmol) in MeOH
2. Experimental
(20 ml) was added to a stirred suspension of
[NEt4]2[Zn(dmio)2] (0.69 g, 1.0 mmol) in MeOH (20
ml). After 3 h, the orange precipitate was collected and
recrystallised from MeOH as a red–brown crystalline
Melting points were measured using a Kofler hot-
stage microscope and are uncorrected. NMR spectra

142
Z.H. Chohan et al. / Journal of Organometallic Chemistry 577 (1999) 140–149
Scheme 1.
solid, m.p. 142–143°C; yield 0.75 g, 66%. Analysis:
Found: C, 31.9; H, 5.1; N, 2.6. Calculated for
C15H30BrNOS4Sn: C, 31.8; H, 5.3; N, 2.5%.
[FcCH2NMe3]2[Zn(dmio)2] (0.47g, 0.50 mmol) in MeOH
(20 ml) and was recrystallised from MeOH; red–brown
crystals, m.p. 134–136°C; yield 0.23 g, 62%. Analysis:
Found: C, 46.3; H, 3.7; N, 1.8. Calculated for
C29H30ClFeNOS4Sn: C, 46.6; H, 4.0; N, 1.9%
1
IR (KBr, cm−1) 1665, 1612, 1475, 1451. H-NMR
(Me2SO-d6, 250 MHz) l: 1.20[t, 6H, J(H–H) 8.1 Hz,
J(119,117Sn–1H) 128,122 Hz, (CH3CH2Sn)], 1.40[tt, 12
Hz, J(H–H) 7.2 Hz, J(H–N) 1.8 Hz, CH3CH2N], 1.56[q,
4H, J(H–H) 8.1 Hz, J(119,117Sn–1H) 59 Hz, CH2Sn],
3.3[q, 8H, J(H–H) 7.2 Hz, CH2N]. 13C-NMR (Me2SO-
d6, 62.9 MHz) l: 7.5 [CH3CH2N], 11.8[J(119,117Sn–13C)
40.5 Hz, CH3CH2Sn], 23.5[J(119,117Sn–13C) 535, 510 Hz,
CH2Sn], 52.7[CH2N], 119.4[CꢀC], 192.5[CꢀO]. 119Sn
(Me2SO-d6, 93.1 MHz) l: −69.7.
IR (KBr, cm−1) 1668, 1603, 1475. 1H-NMR (Me2SO-
d6, 250 MHz) l: 2.89[s, 9H, Me], 4.23[s, 5H, unsubsti-
tuted cp-H], 4.36[s, 4H, substituted cp-H], 4.47[s, 2H,
CH2], 7.42[m, 6H, m-H+p-H], 7.92[m, 4H, J(119,117Sn–
1H) ca. 80 Hz, o-H]. 13C-NMR (Me2SO-d6, 62.9 MHz)
l:
53.0[J(C–N)
7.8
Hz,
Me],
67.1[CH2],
70.6[unsubstituted cp-C], 71.7, 73.6, 74.7[substituted cp-
C], 119.4[C=C], 130.1[J(119,117Sn–13C) 82.2, 79.0 Hz,
m-C],
130.9[J(119,117Sn–13C)
17.5
59.0
Hz,
Hz,
p-C],
o-C],
136.9[J(119,117Sn–13C)
61.8,
2.2. [NEt4][Ph2SnCl(dmio)] (5b)
147.5[J(119,117Sn–13C) 843, 806 Hz, i-C], 191.3[CꢀO].
119Sn (Me2SO-d6, 93.1 MHz) l: −168.3.
This compound was similarly prepared from Ph2SnCl2
(3.45 g, 10.1 mmol) in MeOH (30 ml) and
[NEt4]2[Zn(dmio)2] (3.45 g, 5.0 mmol) in MeOH (30 ml)
and was recrystallised from MeOH; red–brown crystals,
m.p. 133–135°C; yield 5.50 g, 88%. Analysis: Found: C,
44.1; H, 5.0; N, 2.4. Calculated for C23H30ClNOS4Sn: C,
44.6; H, 4.9; N, 2.3%.
2.4. [NEt4][Ph2SnBr(dmio)] (5d)
A solution of [NEt4][Ph2SnCl(dmio)] (2.00 g, 3.23
mmol) and NaBr (1.50 g, 14.6 mmol) in MeOH (20 ml)
was agitated in an ultrasonic bath for 1 h. The dark-or-
ange precipitate was collected and recrystallised from
MeOH; red-brown crystals, m.p. 118–120°C; yield 1.89
g, 86%. Analysis: Found: C, 41.3; H, 4.4; N, 2.1.
Calculated for C23H30BrNOS4Sn: C, 41.7; H, 4.5; N,
2.1%.
IR (KBr, cm−1) 1664, 1614, 1458. 1H-NMR (Me2CO-
d6, 250 MHz) l: 1.34[tt, 12 Hz, J(H–H) 7.2 Hz, J(H–N)
1.85 Hz, Me], 3.41[q, 8H, J(H–H) 7.2 Hz, CH2N],
7.40[m, 6H, m-H+p-H], 8.11[m, 4H, J(119,117Sn–1H) ca.
80 Hz, o-H]. 13C-NMR (Me2CO–d6, 62.9 MHz) l:
7.6[Me], 52.9[J(C–N) 6.2 Hz, CH2], 119.4[CꢀC],
IR (KBr, cm−1) 1663, 1613, 1465. 1H-NMR (Me2SO-
d6, 250 MHz) l: 1.14[tt, 12 Hz, J(H–H) 7.2Hz, J(H–N)
1.8 Hz, Me], 3.16[q, 8H, J(H–H) 7.2 Hz, CH2N], 7.43[m,
6H, m-H+p-H], 7.91[m, 4H, J(119,117Sn–1H) ca. 80 Hz,
o-H]. 13C-NMR (Me2SO-d6, 62.9 MHz) l: 8.8 [Me],
128.7[J(119,117Sn–13C)
82.5,
79.1
Hz,
m-C],
129.6[J(119,117Sn–13C) 16.9 Hz, p-C], 136.6[J(119,117Sn–
13C) 611, 585 Hz, o-C], 148.3[J(119,117Sn–13C) 798, 767
Hz, i-C], 192.0[CꢀO]. 119Sn (Me2CO-d6, 93.1 MHz) l:
−178.5.
53.0[J(C–N)
5.9
Hz,
82.3,79.0
CH2],
118.5[CꢀC],
130.1[J(119,117Sn–13C)
Hz, m-C],
131.0[J(119,117Sn–13C) 17.0 Hz, p-C], 136.9[J(119,117Sn–
13C) 60.0, 58.5 Hz, o-C], 147.6 [J(119,117Sn–13C) 828,791
Hz, i-C], 191.2[CꢀO]. 119Sn (Me2SO-d6, 93.1 MHz) l:
−172.2.
2.3. [FcCH2NMe3][Ph2SnCl(dmio)] (5c)
This compound was prepared similarly from Ph2SnCl2
(0.34 g, 1.00 mmol) in MeOH (20 ml) and

Z.H. Chohan et al. / Journal of Organometallic Chemistry 577 (1999) 140–149
143
Fig. 1. Atom arrangement for the anion of 5b. Probability ellipsoids drawn at 40%.
2.5. [NEt4][Ph2SnI(dmio)] (5e)
CH2N], 7.47[m, 6H, m-H+p-H], 7.82[m, 4H,
J(119,117Sn–1H) ca. 80 Hz, o-H]. 13C-NMR (Me2SO–d6,
62.9 MHz) l: 8.9[Me], 53.0[J(C–N) 5.9 Hz, CH2],
118.5[CꢀC], 130.1[J(119,117Sn–13C) 82.3,79.0 Hz, m-C],
131.0[J(119,117Sn–13C) 17.0 Hz, p-C], 136.9[J(119,117Sn–
13C) 60.6, 58.9 Hz, o-C], 145.9 [J(119,117Sn–13C) 844,
806 Hz, i-C], 191.4[CꢀO]. 119Sn (Me2SO-d6, 93.1 MHz)
l: −159.4.
This compound was similarly prepared from
[NEt4][Ph2SnCl(dmio)], (0.50 g, 0.81 mmol) and NaI
(0.30 g, 2.0 mmol) in MeOH (35 ml) and was recrys-
tallised from MeOH; red–brown crystals, m.p. 147–
149°C; yield 0.46 g, 80%. Analysis: Found: C, 38.6; H,
4.2; N, 4.1. Calculated for C23H30INOS4Sn: C, 38.9; H,
4.3; N, 2.0%.
IR (KBr, cm−1
)
1661, 1614, 1470. 1H-NMR
2.6. [NEt4][Ph2Sn(NCS)dmio)] (5f)
(Me2SO-d6, 250 MHz) l: 1.15[tt, 12 Hz, J(H–H) 7.2
Hz, J(H–N) 1.7 Hz, Me], 3.20[q, 8H, J(H–H) 7.2 Hz,
This compound was similarly prepared from
[NEt4][Ph2SnCl(dmio)], (2.00 g, 3.23 mmol) and
Table 2
˚
Bond lengths (A) and angles (°) for 5b
Table 3
Selected structural details of [Q][R2SnX(dmio)] compound 5
˚
Bond lengths (A)
Sn–S1
Sn–Cl
Sn–C10
C1–S2
C2–S3
C2–S4
C2–C1
2.626(2)
2.524(2)
2.150(7)
1.751(7)
1.750(7)
1.740(8)
1.357(10)
Sn–S4
Sn–C4
C1–S1
C3–S2
C3–S3
C3–O
2.463(2)
2.142(7)
1.734(7)
1.745(9)
1.780(9)
1.204(9)
R
X
Pha
Cl
Et [8b]
Br
Pha [8c]
NCS
Sn–X
Sn–C(A)
Sn–C(B)
Sn–S(eq)
2.524(2)
2.876(2)
2.240(6)
2.142(7)
2.150(7)
2.463(2)
2.626(2)
2.093(8)
2.093(8)
2.465(3)
2.567(3)
166.65(9)
87.6(3)
2.133(7)
2.162(7)
2.433(2)
2.583(2)
Bond angles (°)
S4–Sn–S1
Cl–Sn–S4
Sn–S(ax)
84.2(1)
82.1(1)
114.2(2)
91.5(2)
92.9(2)
96.1(2)
97.3(4)
116.7(5)
116.3(6)
111.9(4)
123.5(7)
116.9(4)
C1–Sn–S1
C4–Sn–S1
C4–Sn–C1
C10–Sn–S4
C10–Sn–C4
C3–S2–C1
C2–S4–Sn
S4–C2–S3
C1–C2–S4
O–C3–S2
165.4(1)
95.8(2)
94.4(2)
X–Sn–S(ax)
X–Sn–C(A)
X–Sn–C(B)
X–Sn–S(eq)
C(A)–Sn–C(B)
C(A)–Sn–S(eq)
C(B)–Sn–S(eq)
C(A)–Sn–S(ax)
C(B)–Sn–S(ax)
S(eq)–Sn–S(ax)
165.4(1)
166.4(2)
94.4(2)
92.9(2)
82.1(1)
117.9(3)
114.2(2)
127.9(2)
95.8(2)
91.5(2)
86.2(1)
90.7(2)
91.7(2)
80.0(2)
116.1(2)
119.8(2)
123.5(2)
95.7(2)
96.1(2)
86.47(6)
C4–Sn–S4
C10–Sn–S1
C10–Sn–C1
C1–S1–Sn
C3–S3–C2
C2–C1–S2
C1–C2–S3
S3–C3–S2
O–C3–S3
87.6(3)
127.9(2)
117.9(3)
97.8(4)
100.0(2)
117.496)
126.4(6)
124.6(8)
126.4(6)
79.86(8)
138.0(6)
110.1(3)
110.1(3)
97.1(3)
97.1(3)
86.78(9)
C2–C1–S1
S2–C1–S1
a For 5b: Q=NEt4; R=Ph; X=Cl: C(A)=C4; C(B)=C10:
S(eq)=S4; S(ax)=S1, in Fig. 1 and Table 2.

144
Z.H. Chohan et al. / Journal of Organometallic Chemistry 577 (1999) 140–149
13C) 80.7, 77.6 Hz, m-C], 131.9[J(119,117Sn–13C) 17.0
Hz, p-C], 137.6[J(119,117Sn–13C) 61.2, 58.8 Hz, o-C],
147.6 [J(119,117Sn–13C) 798, 767 Hz, i-C], 191.3[CꢀO].
119Sn (Me2SO-d6, 93.1 MHz) l: −236.9.
Table 4
Comparison of l119Sn values of 3 and 5 [Q][Ph2SnX(C3S4E)]
X
l
119Sn
l
119Sn
Dl119Sna
E=O (Me2SO-d6) E=S (Me2CO-d6) [8f]
(a) Q=NEt4
3.2. Me2Sn(dmio) (6b)
Cl
−178.5
−143.2
−149.6
−158.2
−162.9
−35.3
−23.3
−21.2
−19.5
Br
I
NCS
−172.2
−179.4
−182.4
This compound was obtained after recrystallisation
from MeOH as an orange microcrystalline solid, m.p.
187–189°C; yield 0.26 g, 40%. Analysis: Found: C,
18.7; H, 1.7. Calculated for C5H6OS4Sn: C, 18.2; H,
1.8%.
(b) Q=FcCH2Nme3
Cl −163.3
−145.8
−146.3(CDCl3)
−17.5
IR (KBr, cm−1) 1662, 1610, 1475, 1467, 1452. H-
1
a Dl119Sn=d119Sn(E=O)−l119Sn(E=S).
NMR (Me2SO-d6, 250 MHz) l: 1.00[s, J(119,117Sn–1H)
82.3, 78.8 Hz, Me]. 13C-NMR (Me2SO-d6, 62.9 MHz)
l: 13.8[J(119,117Sn–13C) 617, 598 Hz, Me], 118.6[CꢀC],
192.5[CꢀO]. 119Sn (Me2SO-d6, 93.1 MHz) l: −37.5.
NaSCN · 2H2O (0.59 g, 5.0 mmol) in MeOH (35 ml)
and was recrystallised from MeOH/Me2CO; red–brown
crystals, m.p. 103–105°C; yield 1.78 g, 86%. Analysis:
Found: C, 45.3; H, 4.8; N, 4.1. Calculated for
C24H30N2OS5Sn: C, 44.9 H, 4.7; N, 4.4%
3.3. Et2Sn(dmio) (6c)
This compound was obtained after recrystallisation
from MeOH as an orange–red crystalline solid, m.p.
196–198°C; yield 0.55 g, 75%. Analysis: Found: C,
23.9, H, 2.9. Calculated for C7H10OS4Sn: C, 23.5; H,
2.8%.
IR (KBr, cm−1) 2057, 1667, 1620, 1475, 1458. H-
1
NMR (Me2SO-d6, 250 MHz) l: 1.14[tt, 12 Hz, J(H–H)
7.5 Hz, J(H–N) 1.7 Hz, Me], 3.17[q, 8H, J(H–H) 7.5
Hz, CH2N], 7.46[m, 6H, m-H+p-H], 7.83[m, 4H,
J(119,117Sn–1H) ca. 80 Hz, o-H]. 13C-NMR (Me2SO-d6,
62.9M Hz) l: 8.8[Me], 53.1[J(C–N) 6.0 Hz, CH2],
118.1[CꢀC], 130.4[J(119,117Sn–13C) 82.5, 79.2 Hz, m-C],
133.6[NCS], 131.0[J(119,117Sn–13C) 17.0 Hz, p-C],
136.8[J(119,117Sn–13C) 60.6, 58.9 Hz, o-C], 145.9
[J(119,117Sn–13C) 869, 818 Hz, i-C], 191.4[CꢀO]. 119Sn
(Me2SO–d6, 93.1 M Hz) l: −182.4.
)
IR (KBr, cm−1 1666, 1612, 1477. 1H-NMR
(Me2SO-d6, 250 MHz) l: 1.32[t, J(H–H) 7.8 Hz,
J(119,117Sn–1H) 128, 122 MHz, Me], 1.54[q, J(H–H) 7.8
Hz, J(119,117Sn–1H) 59 Hz, CH2]. 13C-NMR (Me2SO-d6,
62.9 MHz) l: 12.1[J(119,117Sn–13C) 43.4 Hz, Me],
23.6[J(119,117Sn–13C) 585, 559 Hz, CH2 118.8[CꢀC],
192.9 [CꢀO]. 119Sn (Me2SO-d6, 93.1 MHz) l: −18.2.
3.4. Bu2Sn(dmio) (6d)
3. R2Sn(dmio) compounds
This compound was obtained after recrystallisation
from MeOH as an orange microcrystalline solid, m.p.
178–180°C; yield 0.51 g, 62%. Analysis: Found: C,
31.9; H, 4.4. Calculated for C11H18OS4Sn: C, 32.0; H,
4.4%.
A
solution of R2SnCl2 (2.00 mmol) and
[NEt4]2[Zn(dmio)2] (0.68 g, 1.0 mmol) in Me2CO (30
ml) was stirred for 10–15 min. Water (60 ml) was
added with vigorous stirring. Addition of petroleum
ether (b.p. 40–60°C, 15 ml), with scraping the walls of
the reaction vessel, resulted in the deposition of a
brown to red coloured solid, which was collected and
refluxed for 1 h in H2O/MeOH (2:1 v:v, 50 ml), filtered
and dried under vacuum at 100°C.
1
IR (KBr, cm−1) 1673br, 1481. H-NMR (Me2SO-d6,
250 MHz) l: 0.95[t, 6H, J(H–H) 7.3 Hz, Me], 1.38[m,
4H, CH2], 1.78[m. 8H, CH2CH2]. 13C-NMR (Me2SO-
d6, 62.9 MHz) l: 13.4[Me], 23.9, 26.4, 27.6, 116.6[CꢀC],
192.6 [CꢀO]. 119Sn (Me2SO-d6, 93.1 MHz) l: −22.0.
3.1. Ph2Sn(dmio) (6a)
4. Crystal structure determinations
This compound was sparingly soluble in organic
solvents and was isolated as an orange–red powder.
The product was purified by repeated washings with
water and small quantities of Me2CO; m.p. 197–200°C;
yield 0.81 g, 75%. Analysis: Found: C, 39.9; H, 2.1.
Calculated for C12H10NOS4Sn: C, 39.7; H 2.2%.
4.1. General
The crystals of Me2Sn(dmio)] and [NEt4][Ph2SnCl-
(dmio)], used in the X-ray structure determinations,
were grown from MeOH solutions. Data collection and
cell refinement employed Nicolet P3 software [14]. Data
collection used 2q scan rates of 5.33 (IpB150) to 58.6
IR (KBr, cm−1
)
1662, 1606, 1475. 13C-NMR
(Me2SO-d6, 62.9MHz) l: 118.7[CꢀC], 130.8[J(119,117Sn–

Z.H. Chohan et al. / Journal of Organometallic Chemistry 577 (1999) 140–149
145
Fig. 2. Interactions within a layer of 6b molecules with centroids at 0ByB1/2. Probability ellipsoids drawn at 40%. Symmetry operations; A: x,
y, z; B: 1/2−x, 1/2−y, 1/2+z; C: 1/2+x, 1/2−y, 1−z; D: 1−x, y, 1/2−z; E: 1+x; y, z; F: 3/2−x, 1/2−y, 1/2+z.
(Ip\2500)° min−1, where Ip is the prescan intensity.
Scan widths were 2.4–2.8° 2q. Data reduction used the
program, RDNIC [15]. Refinement was by least squares.
All computations were performed on the SUN SPARC-
server (unix operating system) at the University of
Aberdeen. Structure solution and refinement software:
SHELX86 [16] and SHELX76 [17]. Molecular graphics:
ORTEX [18]. Software used to prepare the data for
publication: XPUB [19].
4.3. [NEt4][Ph2SnCl(dmio)]
All non-H-atoms, except C of the disordered cation,
were refined anisotropically. The nature of the disorder
is such that the methylene C of the cation occupy two
sets of sites C(16, 18, 20, 22) and C(16A, C18A, C20A,
C22A) with occupancies of 0.687(12) and 0.313(12),
respectively. As a consequence no attempt was made to
determine the positions of the alkyl H atoms of the
cation. Phenyl H of the anion, however, were placed in
˚
calculated positions with C–H=0.95 A and refined
4.2. Me2Sn(dmio)
riding upon the C atom to which they were attached
with a common Uiso (final value of 0.091(9)).
Crystal data and structure refinement details are
listed in Table 1.
Absorption correction involved an empirical method
based on psi scans [20]. All non-hydrogens were refined
anisotropically. H-atoms were initially placed in calcu-
˚
lated positions with C–H=0.95 A then refined subject
to distance constraints such that C–H and H···H
(within each methyl group) distances were constrained
to be equal and in the ratio 1:1.633 (18 in all) to control
the shape of the Me groups and Sn···H were fixed at
2.6395 A to control the orientation of the methyl
groups relative to the Sn–C bond. The C–H bond
5. Results and discussion
5.1. Synthesis
˚
The syntheses of [Q][R2Sn(dmio)X] (5) and
[R2Sn(dmio)] 6 are shown in Scheme 1. Two routes to
5 were used: (a) from reaction between R2SnX2 and
[Q]2[Zn(dmio)2] and (b) from halide/pseudohalide ex-
change reaction between [Q][R2Sn(dmio)Cl] and NaX.
distance and a common group Uiso for H were included
˚
in the refinement to yield values of 1.102(5) A and
0.076(16) A , respectively.
2
˚

146
Z.H. Chohan et al. / Journal of Organometallic Chemistry 577 (1999) 140–149
Table 5
solvents (e.g. Me2CO or Me2SO) than in non-coordi-
nating solvents. (e.g. CH2Cl2 or CHCl3).
a
˚
Bond lengths (A) and angles (°) for 6b
˚
Bond lengths (A)
S1–Sn
C4–Sn
C1–S1
C3–S2
C3–S3
C3–O
Sn–Oi
2.440(2)
2.124(7)
1.750(8)
1.757(9)
1.729(10)
1.226(10)
2.654(6)
S4–Sn
C5–Sn
C1–S2
C2–S3
C2–S4
C2–C1
Sn–S4ii
2.487(2)
2.123(7)
1.746(9)
1.747(8)
1.729(9)
1.367(11)
3.649(3)
5.3. Solid state structure of (5b)
As indicated in Section 1, the structures of two
compounds, 5f [8b and 5a [8c], have been reported in
preliminary accounts. The atom arrangements of a
third complex, 5b are shown in Fig. 1. This complex,
like 5f and 5a, exists as an ionic species, with the
geometry at tin in the anion being trigonal bipyramidal.
The axial sites in 5b are occupied by Cl [Sn–Cl=
Bond angles (°)
S4–Sn–S1
C4–Sn–S4
C5–Sn–S4
S1–Sn–Oi
C4–Sn–Oi
S4ii–Sn–Oi
S4ii–Sn–C5
S4ii–Sn–S2
C1–S1–Sn
S2–C1–S1
C2–C1–S2
C1–C2–S3
S3–C3–S2
O–C3–S3
89.47(8)
107.1(3)
102.8(3)
79.43(16)
81.1(3)
126.46(16)
75.2(3)
96.96(15)
97.3(4)
116.4(5)
116.1(6)
116.4(6)
113.3(5)
124.6(7)
97.3(4)
C4–Sn–S1
C5–Sn–S1
C5–Sn–C4
S4–Sn–Oi
C5–Sn–Oi
S4ii–Sn–C4
S4ii–Sn–S1
S4ii–Sn–S4
C2–S4–Sn
C2–C1–S1
S4–C2–S3
C1–C2–S4
C3–S2–C1
O–C3–S2
110.6(3)
115.6(3)
124.2(4)
168.21(16)
78.6(3)
˚
˚
2.524(2) A] and a dithiolate S atom, S1 [Sn–S1=
2.626(2) A] with S1–Sn–C1=165.4(1)°, see Table 2 for
76.6(3)
selected geometric parameters. The equatorial sites are
154.10(7)
64.78(8)
97.1(3)
127.5(7)
116.7(5)
126.8(6)
96.9(4)
occupied by the other dithiolate atom S2 [Sn–S2=
˚
2.463(2) A] and the two carbon atoms, Sn–C4=
˚
2.141(7) and Sn–C10=2.150(7) A. The Sn–Cl bond
length in 5b is comparable to the axial Sn–Cl bond
length in trigonal bipyramidal [NEt4][Ph2SnCl(tdt)]
˚
[2.588(2) A] [6b]. There are no interactions between
122.0(7)
cations and anions, however, there are weak S···S inter-
actions between anions, within twice the van der Waals
C3–S3–C2
˚
a Symmetry operators: (i) 1/2−x, 1/2−y, z−1/2; (ii) −x, y, 1/2−z.
radius of S (1.85 A) [21].
Comparison of the geometric parameters about tin in
the three compounds, 5a,b and f: is available in Table 3.
All three anions have distorted trigonal bipyramidal
geometries with the SnSCCS metallocycles having en-
velope conformations with the flap at tin. There are
relatively small ranges for the Sn–Sax and Sn–Seq bond
lengths and the bite angles of the dmio ligands, all, in
addition, being similar to the equivalent parameters in
the dmit analogues 3 [7f]. However, other bond angles
about tin do show some differences between the three
structures of 5, most noticeably for the equatorial–Sn–
equatorial angles. While the sum of the three equato-
rial–Sn–equatorial angles in each anion do sum up to
ca. 360°, the C–Sn–C angle for 5a [8b] is at 138.0(6)°,
Compounds (6) could also be obtained from R2SnCl2
and [Q]2[Zn(dmio)2] if aqueous extractions were carried
out to remove QX. As found for the analogous dmit
complexes, 3 and 4 [7a,f], 5 could also be formed from
6 on reaction with QX. Conversely, 5 could be con-
verted to 6 on aqueous solution extractions. Hence, in
the preparations of 5, aqueous extractions to remove
inorganic salts, were kept to a minimum.
5.2. [Q][R2SnX(dmio)] 5
Compounds 5 were orange to red–brown in colour.
They were considerably more soluble in coordinating
Fig. 3. Atom arrangement for 6b. Probability ellipsoids drawn at 40%. Symmetry operations: (i) 1/2−x; 1/2−y, z−1/2; (ii) −x, y, 1/2−z.

Z.H. Chohan et al. / Journal of Organometallic Chemistry 577 (1999) 140–149
147
Table 6
119Sn values for 4 and 6
l
R
R2Sn(dmio) [Me2CO-d6] l119Sn
R2Sn(dmit) [Me2SO-d6] l119Sn [7a]
Dl119Sna
Me
Et
Bu
Ph
−37.5
−18.2
−22.0
−235.9
135.2
166.5
161.5
−172.7
−184.7
−183.5
−211.1
−24.8
a Dl119Sn=R2Sn(dmio)−R2Sn(dmit).
more than 20° larger than those in the other two
compounds [8c].
within the sum of the van der Waals radii [21] of 3.70
˚
and 4.05 A for Sn/O and Sn/S, respectively. The Sn–
S4ii interactions involve thiolate S atoms. Similar weak
˚
5.4. Spectra of 5
Sn–S interactions (Sn–S =3.69 A) have been deter-
mined in Bu2Sn(edt) [1e]: two such interactions link
each molecule of Bu2Sn(edt) to neighbouring molecules
[1e]. In both Bu2Sn(edt) and Me2Sn(dmio), Sn2S2 rings
arise as central features of the structures. In
Me2Sn(edt), a single but stronger Sn–S interaction
In the IR spectra in KBr, the range of w(CꢀC) values
were 1451–1475 and those for w(CꢀO) were 1660–1667
and 1609–1614 cm−1. In the NMR spectra in Me2SO2-
d6 solution, l13C(CꢀC) and l13C(CꢀO) were between
118–120 and 191–193ppm, respectively: the l13C(CꢀC)
values for 3 in Me2CO-d6 solution are at a somewhat
lower field (in the range 129.7 and 131.7 ppm) [7f].
Comparison of the l119Sn values of 3 and 5, listed in
Table 4, indicates that the tin atoms in the dmio
complexes are more shielded than in the dmit ana-
logues. Both sets of l119Sn values indicate five-coordi-
nate tin species.
i
˚
[Sn–S =3.18 A] [1a] links molecules into chains.
Table 5 lists bond lengths and angles for 6b. With the
intermolecular Sn–O and Sn–S interactions, the tin
centre becomes six-coordinate, see Fig. 3. The arrange-
ment of the six groups about tin is far from regular, a
description as a highly distorted octahedral complex is
barely acceptable since the trans-angles are 124.2(4),
154.10(7) and 168.21(16)°. Ignoring the weaker Sn–S
interaction, the geometry at tin would be slightly dis-
torted trigonal bipyramidal, with the quasi axial sites
occupied by O and a dithiolate S atom, (S4), (Sn–S4=
5.5. [R2Sn(dmio)] compounds 6
˚
Neutral compounds 6 are orange in colour. They are
also considerably more soluble in coordinating solvents
than in non-coordinating solvents. This, plus the high
m.p.s (between 178 and 200°C), suggest that the
R2Sn(dmio) compounds are aggregated in the solid
state; this was confirmed by the X-ray diffraction study
for Me2Sn(dmio).
2.687(2) A and o-Sn–S(4)=168.21(16)°). The other
dithiolato S atom (S1) in Me2Sn(dmio) forms a slightly
˚
stronger bond to tin (Sn–S1=2.440(2) A). The differ-
ence in the intramolecular Sn–S bond lengths is notice-
ably less than that found in 5. The bite angle of the
dithiolate chelate group in Me2Sn(dmio) is, at 89.47(8)°,
slightly greater than those found in 5 (between 86.2(1)
and 86.47(6)°), this is matched by the Sn–S bond
lengths in Me2Sn(dmio) being on average shorter than
in 5.
5.6. Solid state structure of 6b
The structure consists of aggregated molecules, see
The compounds, Et2Sn(dmit) [7g] and PhMeSn(dmit)
[7a] contain five-coordinate tin atoms with trigonal
bipyramidal geometries in the solid state, as a conse-
quence of intermolecular interactions between the tin
centres and thione sulfur atoms (Sn–S(ꢀC)=3.042(5)
Fig. 2. The major intermolecular interaction is an Sn–
i
˚
O interaction, [Sn–O =2.654(6) A], which links the
molecules into chains parallel to c, with weaker interac-
ii
ii
˚
tions, [Sn–S4 =3.649(3) and S4–S4 =3.430(3) A],
˚
linking the chains into layers: symmetry operators, i:
and 3.139(1) A, respectively); neither molecule exhibits
1/2−x, 1/2−y, z−1/2; ii: −x, y 1/2−z. In addition,
there are S1–S3 [3.595(3) A] interactions within the
intermolecular tin–thiolate bonding.
i
˚
A tin centre in a four-coordinate diorganotin dithio-
late is clearly coordinatively unsaturated and will coor-
dinate, at least in the solid state, with available donor
groups, unless other factors, e.g. steric hindrance, inter-
vene. Complexes of R2Sn(dithiolate) with halide ions
and with nitrogen donors, D, to give [R2SnX(dithio-
late)]− [4a, 6b, 7a,b,f] and [R2Sn(dithiolate) · D] [1c, 3,
7a], respectively, have been isolated for various dithio-
chains. There are no interactions between the layers at
distances less than the sum of appropriate the van der
˚
Waals radii [Sn=2.20, S=1.85 and O=1.50 A] [21].
The intermolecular Sn–O and Sn–S separations are
considerably longer than single covalent bonds, e.g.
˚
˚
1.940(1) A in (Me3Sn)2O [22], and 2.39–2.44 A for
four-coordinate R3SnSR compounds [23], but are

148
Z.H. Chohan et al. / Journal of Organometallic Chemistry 577 (1999) 140–149
lates.
In
the
estertin
compounds,
[8a] and
that ca. 20–40 ppm of the differences in l119Sn values
of 6 and 4 is attributable to the differences between the
dithiolate ligands, the remainder being due to the differ-
ences in the intermolecular donor groups.
(RO2CCH2CH2)2Sn(dmio)
(7)
(RO2CCH2CH2)2Sn(dmit) (8) [7d], the additional coor-
dination, in both solution and in the solid state, is with
the two intramolecular carbonyl groups, while in the
simpler dithiolates, R2Sn(edt) (R=Me or Bu), addi-
tional coordination in the solid state, as mentioned
earlier, concerns dithiolate S atoms of neighbouring
molecules. On dissolution, however, the intermolecular
associations in R2Sn(edt) are broken with the formation
of four-cordinate compounds [1e, 2a]. The bulkier
tBu2Sn(edt) is monomeric in both the solid state and in
solution [1f].
References
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Holmes, Inorg. Chem. 20 (1981) 3076.
Despite the differing intermolecular interactions in 4
and 6, the two sets of monomers have similar struc-
tures, with the chelate bite angles, the intramolecular
Sn–S bond lengths, and geometric parameters of the
metallocyclic [SnSCCS] units in 4 and 6 being very
similar.
5.7. Spectra
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In the IR spectra of 6 in KBr, w(CꢀC) occurs at
1452–1461 cm−1 and w(CꢀO) at 1662–1673 and 1610–
1615 cm−1; in the NMR spectra in Me2SO-d6, l(CꢀC)
and l(CꢀO) are in the ranges 116.7–118.8 and 191.3–
192.6 ppm, respectively. Values for the CꢀC unit in the
analogous dmit compounds, 4, were w(CꢀC)=1433–
1456 cm−1 and l(CꢀC) 129.5–130.3 ppm in Me2CO
solution [7a]. Again, l(CꢀC) values for the dmio com-
pounds appear at higher field.
The solution l119Sn values of 6 in Me2SO solution
are shown in Table 6. The values suggest five-coordi-
nate tin centres, i.e. the Sn–O interactions still persist
in solution. The weaker intermolecular interactions are
probably absent as found with R2Sn(edt) in solution.
Comparison of the solution l119Sn values of 6 and 4 in
Table 6 indicate that the dmio componds exhibit the
higher field values (by between 170 and 211 ppm). The
differences in the l119Sn values, (Dl119Sn=
l119Sn[R2Sn(dmio)]-l119Sn[R2Sn(dmit)]) reflect both
the differences in the dithiolate units and the inter-
molecular associations. The l119Sn values for the six
coordinate species, 7 [8a] and 8 [7d], are 48.2 and 89.7
ppm, respectively, in CDCl3 solution. From these val-
ues and l119Sn values for 3 and 5, it can be estimated
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Doidge-Harrison, Polyhedron 16 (1997) 2689.

Z.H. Chohan et al. / Journal of Organometallic Chemistry 577 (1999) 140–149
149
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