Syntheses, crystal structures and coordination modes of tri- and di-organotin derivatives with 2-mercapto-4-methylpyrimidine

Article abstract of DOI:10.1016/j.jorganchem.2004.10.020

The organotin (IV) derivatives of 2-mercapto-4-methylpyrimidine (Hmpymt) R₃SnL (R = Ph 1, PhCH₂ 2, n-Bu 3), R₂SnCl _mL_n (m = 1, n = 1, R = CH₃ 4, Ph 5, n-Bu 6, PhCH₂ 7; m = 0, n =

Full text of DOI:10.1016/j.jorganchem.2004.10.020

Journal of Organometallic Chemistry 690 (2005) 519–533
www.elsevier.com/locate/jorganchem
Syntheses, crystal structures and coordination modes of tri- and
di-organotin derivatives with 2-mercapto-4-methylpyrimidine
a,b,
a
a
a
Chunlin Ma
*, Junhong Zhang , Guangru Tian , Rufen Zhang
a
Department of Chemistry, Liaocheng University, Liaocheng 252059, Peopleꢀs Republic of China
b
Taishan University, Taian 271021, Peopleꢀs Republic of China
Received 10 August 2004; accepted 5 October 2004
Abstract
The organotin (IV) derivatives of 2-mercapto-4-methylpyrimidine (Hmpymt) R3SnL (R = Ph 1, PhCH2 2, n-Bu 3), R2SnClmLn
(m = 1, n = 1, R = CH3 4, Ph 5, n-Bu 6, PhCH2 7; m = 0, n = 2, R = CH3 8, n-Bu 9, Ph 10, PhCH2 11) were obtained by the reaction
of the organotin(IV) chlorides R3SnCl or R2SnCl2 with 2-mercapto-4-methylpyrimidine hydrochloride (HCl Æ Hmpymt) in 1:1 or 1:2
molar ratio. All complexes 1–11 were characterized by elemental analyses, IR, 1H, 13C and temperature-dependent 119Sn NMR spec-
tra. Except for complexes 3 and 6, the structures of complexes 1, 2, 4, 5, 7, 8–11 were confirmed by X–ray crystallography. Including
tin-nitrogen intramolecular interaction, the tin atoms of complexes 1–7 are all five-coordinated and their geometries are distorted
trigonal bipyramidal. While the tin atoms of complexes 8–11 are six-coordinated and their geometries are distorted octahedral.
Besides, the ligand adopts the different coordination modes to bond to tin atom between the complexes 1, 6, 7 and 2, 3, 4, 5, 8–
11. Furthermore, intermolecular Snꢀ ꢀ ꢀN or Snꢀ ꢀ ꢀS interactions were recognized in crystal structures of complexes 4, 7 and 11,
respectively.
ꢀ 2004 Elsevier B.V. All rights reserved.
Keywords: 2-Mercapto-4-methylpyrimidine; Organotin; Crystal structures
1. Introduction
logical activities. In recent years, several investigations
to test their antitumour activities have been carried out
and much attention has been focused on their antitu-
mour properties and their implications in antioncogene-
sis [3]. Also, they are used commercially as bactericides,
fungicides, acaricides and industrial and agriculture bio-
cides [4,5]. The presence of 2-mercaptopyrimidine nucle-
otides has been detected in Escherichia coli sRNA and
yeast tRNA, it was found to inhibit the synthesis of
tRNA and thus it acts as an antitumour and antithyroid
agent [6]. A similar inhibitory effect has been found for
pyrimidine-2-thione (Hpymt) and the compound also
shows pronounced in vitro bacteriostatic activity [7].
To continue our studies on the coordination of
organotin(IV) moieties by thiol sulfur and heterocy-
clic nitrogen [8–10] we choose another ligand: 2-merca-
pto-4-methylpyrimidine (Hmpymt), similar to the
The coordination chemistry of tin is extensive with
various geomertries and coordination numbers known
for both inorganic and organometallic complexes [1].
Higher coordination numbers can be generated either
by inter- and/or intra-molecular interaction, especially
in complexes where tin bonds to electronegative atoms,
such as oxygen, nitrogen and sulfur. Studies of adducts
of organotin halides continue to provide fundamental
information about both the Lewis acid-base model and
the reactivity of organotin species [2]. Furthermore,
organotin(IV) complexes show a large spectrum of bio-
*
Corresponding author. Tel.: +86 635 8258579; fax: +86 538
6715521.
E-mail address: macl@lctu.edu.cn (C. Ma).
0022-328X/$ - see front matter ꢀ 2004 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2004.10.020

520
C. Ma et al. / Journal of Organometallic Chemistry 690 (2005) 519–533
1
2-mercaptopyrimidine (Hpymt) and 4,6-dimethylpyrim-
idine-2-thione (Me2PymtH) [11], they belong to the
same class as the nucleic acid bases. It is worth to note
that since the 2-mercapto-4-methylpyrimidine is an
unsymmetrical ambidentate ligand, besides, with the
cooperation between steric repulsion and interactions
[12,13], its N,S-bidentate coordination to the tin atom
generates linkage isomerism. As shown in Fig. 1, there
is an adjacent isomer with the C4 methyl group of the
pyrimidine ring near the Rn– chelates (A) and a remote
isomer with the C4 methyl group distant from the Rn–
chelates (B). In this paper, we reported the syntheses,
crystal and molecular structures of the related organotin
derivatives 1–11, which exhibit versatile structures,
based upon different coordination modes of Hmpymt
(Scheme 1).
All complexes 1–11 were characterized by elemental
analyses, IR, 1H NMR, 13C NMR and 119Sn NMR
spectra. Except for complexes 3 and 6, complexes 1, 2,
4, 5, 7, 8–11 have been determined by X-ray crystallog-
raphy. From the crystal structures, we can see that in
complexes 2, 4, 5 and 9–11, the ligand adopts mode B
to bond to tin atom through the 1-nitrogen and 2-sulfur
donors, while adopts mode A to bond to tin atom
through the 3-nitrogen and 2-sulfur donors in complexes
1 and 7, and not only through the 1-nitrogen and 2-sul-
fur donors but also through the 3-nitrogen and 2-sulfur
donors mode in complex 8.
75.3, 149.2 MHz, respectively. The H and 13C spectra
were acquired at room temperature (298 K) and 119Sn
NMR were obtained at different temperature unless oth-
erwise specified; 13C spectra are broadband proton
decoupled. The chemical shifts were reported in ppm
with respect to the references and were stated relative
to external tetramethylsilane (TMS) for H, 13C NMR,
and to neat tetramethyltin for 119Sn NMR. Elemental
analyses were performed with a PE–2400II apparatus.
1
2.2. Synthesis
The general route of synthesis is shown in the follow-
ing. The reaction was carried out under nitrogen atmos-
phere with use of standard Schlenk technique. The 2-
mercapto-4-methylpyrimidine hydrochloride (Hmpymt Æ
HCl) and the sodium salt of ethanol were added to the
solution of benzene, the mixture was stirred for 30
min, and then added organotin(IV) chlorides to the mix-
ture, continuing the reaction about 12 h at 40 ꢁC. After
cooling down to room temperature, filtered it. The sol-
vent of the filtrate was gradually removed by evapora-
tion under vacuum until solid product was obtained.
The details of synthetic experiments of complexes 1–11
were shown in Table 1.
2.2.1. Ph3Sn(SC5H5N2) (1)
Recrystallized from ether–dichloromethane; m.p.
131–133 ꢁC. Yield, 80%. Anal. Calc. for C23H20N2SSn:
C, 58.14; H, 4.24; N, 5.92. Found: C, 58.16; H, 4.21;
N, 5.89. IR (KBr, cmꢁ1): 1632 (C@N), 701 (s, C–S),
2. Experimental
1
560 (m, Sn–C), 448 (w, Sn N), 317 (m, Sn–S). H
2.1. Materials and measurements
NMR (CDCl3): d 7.36–7.79 (2JSnH = 56 Hz, 15H), 1.33
(s, 3H), 6.71(d, 1H, JHH = 6 Hz), 8.20 (d, 1H, JHH = 9
Hz). 13C NMR (CDCl3): d 172.87 (C2), 167.54 (C4),
156.51 (C6), 115.85 (C5), 23.35 (4-CH3), 128.2 (m-C),
129.3 (p-C), 136.7 (o-C), 142.6 (i-C). 119Sn NMR
(CDCl3, 298 K): ꢁ57 ppm.
Triphenyltin chloride, tribenzyltin chloride, tributyl-
tin chloride, diphenyltin dichloride, di-n-butyltin
dichloride, dimethyltin dichloride and 2-mercapto-
4-methylpyrimidine hydrochloride (HCl Æ Hmpymt)
were commercially available, and they were used with-
out further purification. Dibenzyltin dichloride were
prepared by a standard method reported in the literature
[14]. The melting points were obtained with Kofler mi-
cro melting point apparatus and were uncorrected.
Infrared-spectra were recorded on a Nicolet–460 spec-
trophotometer using KBr discs and sodium chloride op-
tics. 1H and 13C 119Sn NMR spectra were recorded on a
Bruker AMX–300 spectrometer operating at 300 and
2.2.2. (PhCH2)3Sn(SC5H5N2) (2)
Recrystallized from hexane–dichloromethane; m.p.
148–150 ꢁC. Yield, 85%. Anal. Calc. for C26H26N2SSn:
C, 60.38; H, 5.67; N, 5.44. Found: C, 60.33; H, 5.64;
N 5.41. IR (KBr, cmꢁ1): 1631(C@N), 702 (s, C–S),
1
562 (m, Sn–C), 450 (w, Sn N), 315 (m, Sn–S). H
NMR (CDCl3): d 7.46–7.79 (m, 15H), 3.26 (2JSnH = 66
Hz, 6H, CH2–Ph), 2.32 (s, 3H), 6.66 (d, 1H, J HH = 6
Hz), 7.79 (d, 1H, JHH = 9 Hz). 13C NMR: d 181.76
(C2), 172.54 (C4), 156.97 (C6), 117.85 (C5), 24.09
1
CH3
(CH3), 37.5 (CH2–Ph, JSnC = 330 Hz), 127.4 (m-C),
128.2 (p-C), 127.3(o-C), 124.2 (i-C). 119Sn NMR
(CDCl3, 298 K): ꢁ55 ppm.
S
2
4
3
N
3
5
6
N
2
SnRn
SnRn
H3C
N
4
1
S
N
5
6
1
2.2.3. (n-Bu)3Sn(SC5H5N2) (3)
Recrystallized from hexane–dichloromethane; m.p.
86–88 ꢁC. Yield, 70%. Anal. Calc. for C17H32N2SSn:
(a)
(b)
Fig. 1. (a) Adjacent; (b) remote.

C. Ma et al. / Journal of Organometallic Chemistry 690 (2005) 519–533
521
CH3
Ph
N
( 1 )
Sn Ph
Ph
CH3
S
N
N
EtONa
R3SnCl
+
R
R=PhCH2
( 2 );
( 3 )
S
N
SH.HCl
N
R
Sn
H3C
N
R= n-Bu
R
R
Sn
R
S
N
R=CH3
R=Ph
( 4 );
( 5 )
H3C
CH3
N
Cl
N
EtONa
R2SnCl2
+
CH3
R
SH.HCl
N
R=n-Bu
( 6 );
N
Sn Cl
R
R=PhCH2 ( 7 )
S
N
CH3
CH3
Sn
CH3
N
S
( 8 )
N
CH3
N
S
CH3
N
N
EtONa
2
R SnCl
+
2
2
R
S
S
R=n-Bu ( 9 );
N
N
SH.HCl
N
Sn
R
R=Ph
(10);
H3C
N
CH3
N
R=PhCH2 (11)
Scheme 1.
Table 1
The details of synthetic experiments of complexes 1–11
Complexes
RmSnCln
RmSnCln:Hmpymt Æ HCl:EtONa
Products
1
2
Ph3SnCl
1:1:2
1:1:2
1:1:2
1:1:2
1:1:2
1:1:2
1:1:2
1:2:4
1:2:4
1:2:4
1:2:4
Ph3Sn(SC5H5N2)
(PhCH2)3SnCl
(n-Bu)3SnCl
(CH3)2SnCl2
Ph2SnCl2
(PhCH2)3Sn(SC5H5N2)
(n-Bu)3Sn(SC5H5N2)
Me2ClSn(SC5H5N2)
Ph2ClSn(SC5H5N2)
3
4
5
6
(n-Bu)2SnCl2
(PhCH2)2SnCl2
(CH3)2SnCl2
(n-Bu)2SnCl2
Ph2SnCl2
(n-Bu)2ClSn(SC5H5N2)
(PhCH2)2ClSn(SC5H5N2)
Me2Sn(SC5H5N2)2
7
8
9
(n-Bu)2Sn(SC5H5N2)2
Ph2Sn(SC5H5N2)2
(PhCH2)2Sn(SC5H5N2)2
10
11
(PhCH2)2SnCl2
C, 48.21; H, 7.77; N, 6.75. Found: C, 48.19; H, 7.75; N
6.72. IR (KBr, cmꢁ1): 1631(C@N), 703 (s, C–S), 565 (m,
Sn–C), 453 (w, Sn N), 318 (m, Sn–S). 1H NMR
(CDCl3): d 1.26–1.75 (2JSnH = 69 Hz, 18H), 0.89 (t,
9H), 2.31 (s, 3H), 6.68 (d, 1H, JHH = 7 Hz), 7.80 (d,
1H, JHH = 10 Hz). 13C NMR: d 181.79 (C2), 172.56
(C4), 156.77 (C6), 118.85 (C5), 24.11 (CH3), 13.6, 26.4,
27.6, 29.7 (nBu). 119Sn NMR (CDCl3, 298 K): ꢁ51 ppm.
2.2.4. Me2ClSn(SC5H5N2) (4)
Recrystallized from hexane–dichloromethane; m.p.
124–126 ꢁC. Yield, 78%. Anal. Calc. for C7H11ClN2SSn:
C, 27.18; H, 3.58; N, 9.09. Found: C, 27.15; H, 3.55; N
9.06. IR (KBr, cmꢁ1): 1631(C@N), 700 (s, C–S), 569 (m,
Sn–C), 480 (w, Sn N), 318 (m, Sn–S), 272 (m, Sn–Cl).
1H NMR (CDCl3): d 0.91 (2JSnH = 72 Hz, 6H), 2.38 (s,
3H), 6.76 (d, 1H, JHH = 7 Hz), 7.81 (d, 1H, JHH = 12

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C. Ma et al. / Journal of Organometallic Chemistry 690 (2005) 519–533
2
Hz). 13C NMR (CDCl3): d 181.83 (C2), 172.56 (C4),
156.97 (C6), 117.75 (C5), 24.06 (4-CH3), 10.6 (CH3,
1JSnC = 490 Hz). 119Sn NMR (CDCl3, 298 K): ꢁ77.6
ppm.
(CDCl3): d 1.05 (s, 6H, JSnH = 80 Hz), 1.31 (s, 3H),
2.36 (s, 3H), 6.68 (d, 1H, JHH = 7 Hz), 6.75 (d, 1H,
JHH = 8 Hz), 7.83 (d, 1H, JHH = 10 Hz), 8.24 (d, 1H,
JHH = 12 Hz). 13C NMR (CDCl3): d 181.79, 179.73
(C2), 171.72, 166.7 (C4), 157.41, 156.45 (C6), 117.78,
115.2 (C5), 24.01, 23.84 (4-CH3), 10.9 (CH3, 1JSnC = 546
Hz). 119Sn NMR (CDCl3, 298 K): ꢁ121 ppm.
2.2.5. Ph2ClSn(SC5H5N2) (5)
Recrystallized from hexane–dichloromethane; m.p.
120–122 ꢁC. Yield, 76%. Anal. Calc. for C17H17ClN2SSn:
C, 47.12; H, 3.95; N, 6.46. Found: C, 47.10; H, 3.92; N
6.43. IR (KBr, cmꢁ1): 1631(C@N), 701 (s, C–S), 568
(m, Sn–C), 483 (w, Sn N), 318 (m, Sn–S), 280 (m,
Sn–Cl). d 7.45–7.91 (2JSnH = 74 Hz, 10H), 2.33 (s, 3H),
6.69 (d, 1H, JHH = 7 Hz), 8.22 (d, 1H, JHH = 10 Hz).
13C NMR (CDCl3): d 179.79 (C2), 170.56 (C4), 156.64
(C6), 116.97 (C5), 23.69 (4-CH3), 124.7 (3JSnC = 50 Hz,
m-C), 129.6 (4JSnC = 12 Hz, p-C), 136.9 (2JSnC = 36 Hz,
o-C), 146.5 (1JSnC = 597 Hz, i-C). 119Sn NMR (CDCl3,
298 K): ꢁ175 ppm.
2.2.9. (n-Bu)2Sn(SC5H5N2)2 (9)
Recrystallized from ether–dichloromethane; m.p. 220
ꢁC (dec.). Yield, 74%. Anal. Calc. for C18H28N4S2Sn: C,
44.74; H, 5.84; N, 11.64. Found: C, 44.72; H, 5.81; N,
11.60. IR (KBr, cmꢁ1): 1635 (m, C@N), 701 (s, C–S),
563 (m, Sn–C), 453 (w, Sn N), 319 (m, Sn–S).
1H NMR (CDCl3):
d
1.10–1.75 (2JSnH = 73 Hz,
–CH2CH2CH2); 0.95 (t, –CH3), 2.31 (s, 6H), 6.69 (d,
2H, JHH = 8 Hz), 7.83 (d, 2H, JHH = 13 Hz). 13C
NMR (CDCl3): d 181.79 (C2), 171.72 (C4), 157.81
(C6), 117.41 (C5), 23.96 (4-CH3), 13.6, 26.4, 27.6, 29.7
(nBu, JSnC = 515 Hz, JSnC = 38 Hz, JSnC = 106 Hz).
119Sn NMR (CDCl3, 298 K): ꢁ81 ppm.
1
2
3
2.2.6. (n-Bu)2ClSn(SC5H5N2) (6)
Recrystallized from hexane–dichloromethane; m.p.
100–102 ꢁC. Yield, 75%. Anal. Calc. for
C13H23ClN2SSn: C, 39.67; H, 5.89; N, 7.12. Found: C,
39.65; H, 5.91; N 7.10. IR (KBr, cmꢁ1): 1631(C@N),
703 (s, C–S), 561 (m, Sn–C), 481(w, Sn N), 316 (m,
2.2.10. Ph2Sn(SC5H5N2)2 (10)
Recrystallized from ether–dichloromethane; m.p.
193–195 ꢁC. Yield, 76%. Anal. Calc. for C22H20N4S2Sn:
C, 50.50; H, 3.85; N, 10.75. Found: C, 50.47; H, 3.81; N,
10.71. IR (KBr, cmꢁ1): 1635 (m, C@N), 701 (s, C–S),
1
Sn–S), 273 (m, Sn–Cl). H NMR (CDCl3): d 1.57–1.75
(2JSnH = 70 Hz, 12H), 0.87 (t, 6H), 1.37 (s, 3H), 6.68
(d, 1H, JHH = 6 Hz), 8.23 (d, 1H, JHH = 13 Hz). 13C
NMR (CDCl3): d 181.86 (C2), 172.66 (C4), 156.92
(C6), 117.55 (C5), 24.07 (4-CH3), 24.11 (4-CH3), 13.6,
1
564 (m, Sn–C), 460 (w, Sn N), 320 (m, Sn–S). H
NMR (CDCl3): d 7.45–7.91 (2JSnH = 75 Hz, 15H), 2.32
(s, 6H), 6.68 (d, 2H, JHH = 7 Hz), 8.01 (d, 2H,
JHH = 12 Hz). 13C NMR (CDCl3): d 181.78 (C2),
171.69 (C4), 155.74 (C6), 117.53(C5), 24.02 (4-CH3),
128.6 (3JSnC = 53 Hz, m-C), 129.3 (4JSnC = 18 Hz, p-
C), 134.5 (2JSnC = 33 Hz, o-C), 146.5 (1JSnC = 561 Hz,
i-C). 119Sn NMR (CDCl3, 298 K): ꢁ129 ppm.
1
2
26.4, 27.6, 29.7 (nBu, JSnC = 494 Hz, JSnC = 36.6 Hz,
3JSnC = 101.7 Hz). 119Sn NMR (CDCl3, 298 K): ꢁ76.2
ppm.
2.2.7. (PhCH2)2SnCl(SC5H5N2) (7)
Recrystallized from ether–dichloromethane; m.p.
146–148 ꢁC. Yield, 72%. Anal. Calc. for
C19H19ClN2SSn: C, 49.44; H, 4.15; N, 6.10. Found: C,
49.41; H, 4.11; N, 6.07. IR (KBr, cmꢁ1): 1635(C@N),
701 (s, C–S), 561 (m, Sn–C), 475 (w, Sn N) 316 (m,
2.2.11. (PhCH2)2Sn(SC5H5N2)2 (11)
Recrystallized from ether–dichloromethane; m.p.
128–130 ꢁC. Yield, 82%. Anal. Calc. for C24H24N4S2Sn:
C, 52.29; H, 4.39; N, 10.21. Found: C, 52.25; H, 4.36; N,
10.21. IR (KBr, cmꢁ1): 1635 (m, C@N), 701 (s, C–S),
1
Sn–S), 278 (m, Sn–Cl). H NMR (CDCl3): d 7.46–7.79
(m, 15H), 3.29 (2JSnH = 87 Hz, 4H), 1.35 (s, 3H), 6.69
(d, 1H, JHH = 7 Hz), 8.22 (d, 1H, JHH = 13 Hz). 13C
NMR (CDCl3): d 179.76 (C2), 170.52 (C4), 156.67
(C6), 116.93 (C5), 23.69 (4-CH3), 38.5 (CH2–Ph,
1JSnC = 650 Hz), 125.4 (4JSnC = 30 Hz, m-C), 127.0
(5JSnC = 26 Hz, p-C), 130.5 (3JSnC = 44 Hz, o-C), 139.0
(2JSnC = 36 Hz, i-C). 119Sn NMR (CDCl3, 298 K):
ꢁ172 ppm.
1
561 (m, Sn–C), 473 (w, Sn N), 321 (m, Sn–S). H
NMR (CDCl3): d 7.46–7.79 (m, 15H), 3.47 (2JSnH = 83
Hz, 6H, CH2–Ph), 2.35 (s, 6H, JHH = 6 Hz), 6.67 (d,
2H, JHH = 12 Hz), 7.82 (d, 2H). 13C NMR (CDCl3): d
181.73 (C2), 171.78 (C4), 157.89 (C6), 117.64(C5),
1
24.07 (4-CH3), 37.3 (CH2–Ph, JSnC = 686 Hz), 127.4
(4JSnC = 31 Hz, m-C), 128.2 (5JSnC = 25 Hz, p-C),
127.3 (3JSnC = 48 Hz, o-C), 124.2 (2JSnC = 34 Hz, i-C).
119Sn NMR (CDCl3, 298 K): ꢁ257 ppm.
2.2.8. Me2Sn(SC5H5N2)2 (8)
Recrystallized from ether; m.p. 218–210 ꢁC. Yield,
85%. Anal. Calc. for C12H16N4S2Sn: C, 36.11; H, 4.04;
N, 14.10. Found: C, 36.08; H, 4.01; N, 14.06. IR
(KBr, cmꢁ1): 1635 (m, C@N), 700 (s, C–S), 567 (m,
Sn–C), 488 (w, Sn N), 320 (m, Sn–S). 1H NMR
2.3. X-ray structure analyses of 1, 2, 4, 5, 7, 8–11
Crystals were mounted in Lindemann capillaries un-
der nitrogen. Diffraction data were collected on a

C. Ma et al. / Journal of Organometallic Chemistry 690 (2005) 519–533
523
Smart–1000 CCD area-detector with graphite mono-
˚
Furthermore, the weak- or medium-intensity absorp-
tions at the region of 448–483 cmꢁ1 in all complexes
1–11 have been assigned to Sn N vibration [18]. The
m(Sn–Cl) absorptions at the region of 272–280 cmꢁ1 in
complexes 4–7 are close to those found in trichlorometh-
ylbis(imidazole)tin Æ H2O (275 cmꢁ1) and (PhCH2)2SnCl
(BzACDA) (282 cmꢁ1) [19,20].
chromated Mo Ka radiation (k = 0.71073 A). A semi-
empirical absorption correction was applied to the
data. The structure was solved by direct methods using
SHELXS-97 and refined against F2 by full matrix least-
squares using SHELXL-97. Hydrogen atoms were
placed in calculated positions. Crystal data and exper-
imental details of the structure determinations of 1 and
2, 4, 5 and 7, and 8–11 are listed in Tables 2–4,
respectively.
In the 1H NMR spectrum, one methyl signal has
similar chemical shift at the region of 1.33–1.35 ppm
in complexes 1, 6 and 7, similar methyl groups signal
appears at the region of 2.31–2.38 ppm in complexes
2, 3, 4, 5 and 9–11, while two methyl signals appear
at both 2.36 and 1.31 ppm in complex 8. These results
mean that adjacent isomer A of mpymt ligand exists in
complexes 1, 6 and 7, remote isomer B exists in com-
plexes 2, 3, 4, 5 and 9–11, while both remote and
adjacent coordination modes exist in complex 8,
respectively.
3. Results and discussion
3.1. Spectra
The IR spectra show that the strong absorption at
2650 cmꢁ1 in free ligand due to the –SH group is absent
in spectra of all complexes 1–11, while new absorption
appears in 315–321 cmꢁ1 region. All these values are lo-
cated within the range for Sn–S vibration observed in
common organotin derivatives of thiolate (300–400
cmꢁ1) [15], consequently, they can be assigned to
m(Sn–S). The middle intensity bands observed at 1635
cmꢁ1 in the spectra of all complexes 1–11 have been
assignable to m(C@N) according to literatures [16,17]
The 13C NMR spectra of all complexes 1–11 show a
significant downfield shift of all carbon resonances. The
shift is a consequence of an electron density transfer from
n
the ligand to the acceptor. The J(119Sn–13C) coupling
constants were detected in the case of sufficiently soluble
derivatives. In complexes 4–7, the order of magnitude of
the coupling constants is the same as those previously re-
ported for analogous five-coordinate derivatives [7],
whereas in the case of derivatives 8–11, the nJ(119Sn–13C)
Table 2
Crystal, data collection and structure refinement parameters of complexes 1 and 2
Complexes
1
2
Empirical formula
Formula weight
˚
Wavelength (A)
C
475.16
23H20N2SSn
C26H26N2SSn
517.24
0.71073
0.71073
Orthorhombic
Crystal system
Space group
Triclinic
ꢀ
Pbca
9.450(5)
P
12.262(16)
˚
a (A)
˚
b (A)
15.544(8)
28.197(13)
14.122(18)
14.369(19)
˚
c (A)
a (ꢁ)
b (ꢁ)
c (ꢁ)
90
90
78.42(2)
80.331(19)
90
4142(3)
89.329(19)
2402(5)
3
˚
V (A )
Z
4
1.524
4
1.430
Dcalc (Mg mꢁ3
F(000)
)
1904
1.344
1048
1.165
l (mmꢁ1
)
Crystal size (mm)
h Range
Index ranges
0.450.38 · 0.32
1.44–25.03
0.45 · 0.37 · 0.13
1.47–25.03
ꢁ11 6 h 6 11; ꢁ18 6 k 6 16; ꢁ30 6 l 6 33
20384
ꢁ14 6 h 6 13; ꢁ16 6 k 6 16; ꢁ17 6 l 6 11
12351
Reflections collected
Unique reflections
Absorbtion correction
Max/min transmission
Data, restrainst, parameters
GOF
3655(Rint = 0.0460)
Semi-empirical from equivalents
0.6730, 0.5830
8401(Rint = 0.0257)
Semi-empirica from equivalents
0.8633, 0.6222
3655, 0, 244
1.133
8401, 0, 541
0.866
Final R indices [I > 2r(I)]
R indices (all data)
Largest difference peak, hole (e A
R1 = 0.0352, wR2 = 0.0830
R1 = 0.0583, wR2 = 0.1029
0.538, ꢁ0.405
R1 = 0.0389 wR2 = 0.0711
R1 = 0.0768, wR2 = 0.0806
0.603, ꢁ0.481
ꢁ3
˚
)

524
C. Ma et al. / Journal of Organometallic Chemistry 690 (2005) 519–533
Table 3
Crystal, data collection and structure refinement parameters of complexes 4, 5 and 7
Complexes
4
5
7
Empirical formula
Formula weight
C7H11N2SClSn
309.38
C17H15ClN2SSn
433.51
C19H19N2SClSn
461.56
˚
Wavelength (A)
0.71073
Monoclinic
0.71073
Orthorhombic
0.71073
Orthorhombic
Pnma
Crystal system
Space group
C2/m
20.456(10)
Pca21
21.899(10)
˚
a (A)
11.495(11)
15.353(15)
˚
b (A)
7.613(4)
7.549(4)
9.544(4)
17.274(8)
˚
c (A)
10.846(11)
90
a (ꢁ)
b (ꢁ)
c (ꢁ)
90
95.056(8)
90
90
90
90
90
1171.1(10)
90
3610(3)
3
˚
V (A )
1914(3)
4
1.602
Z
4
1.755
8
1.595
Dcalc (Mg mꢁ3
F(000)
)
600
2.544
1712
1.676
920
1.586
l (mmꢁ1
Crystal size (mm)
)
0.50 · 0.40 · 0.29
2.00–25.02
0.53 · 0.44 · 0.13
1.86–25.02
0.45 · 0.29 · 0.25
2.30–25.02
h Range
Index ranges
ꢁ21 6 h 6 24
ꢁ9 6 k 6 8
ꢁ25 6 h 6 26
ꢁ11 6 k 6 11
ꢁ15 6 l 6 20
18140
ꢁ12 6 h 6 13
ꢁ18 6 k 6 16
ꢁ12 6 l 6 12
9529
ꢁ8 6 l 6 8
Reflections collected
Unique reflections
3087
1109(Rint = 0.0888)
Semi-empirical from equivalents
0.5258, 0.3628
1109, 0, 70
5464(Rint = 0.0438)
Semi-empirical from equivalents
0.8116, 0.4703
5464, 1, 397
0.935
1761(Rint = 0.0362)
Semi-empirical from equivalents
0.6925, 0.5355
1761, 0, 124
1.113
Absorbtion correction
Max/min transmission
Data, restrainst, parameters
GOF
1.021
Final R indices [I > 2r(I)]
R indices (all data)
Largest difference peak, hole (e A
R1 = 0.0504 wR2 = 0.1134
R1 = 0.0767, wR2 = 0.1522
0.959, ꢁ0.548
R1 = 0.0312 wR2 = 0.0606
R1 = 0.0494 wR2 = 0.0657
0.273, ꢁ0.297
R1 = 0.0298, wR2 = 0.0682
R1 = 0.0426, wR2 = 0.0754
0.569, ꢁ0.390
ꢁ3
˚
)
are close to those found for six-coordinate skewed tra-
pezoidal diorganotin(IV) complexes [21,22].
shifts of 4–7 are in accordance with those of five coor-
dinate diorganotin(IV) halides complexes involving ha-
lide or phosphine lignds [26], as well as chelating
S-donors and O-donors complexes [27,28]. Five-coordi-
nate ClPh2SnXY compounds (X and Y = electronega-
tive groups) in solution have 119Sn NMR values in
the region ꢁ140 to ꢁ180 ppm depending on the groups
present [29,30] and are rather independent of the tem-
perature. For example, the spectrum of complex 5 re-
veals one narrow signal in the whole temperature
range. The value of 119Sn chemical shift changes only
slightly with a decrease in the temperature (ꢁ175 ppm
at 298 K and ꢁ180 ppm at 195 K, respectively). Which
suggests that the Sn–N interaction probably survives in
solution and that a five-coordinate species is main-
tained. While the 119Sn NMR chemical shift of 8–11
are not informative enough. The chemical shift values
of complexes 8 and 11 are ꢁ121, ꢁ257 ppm at 298
K, and ꢁ125, ꢁ260 ppm at 195 K, respectively. Which
can belong to penta- or weakly hexacoordinated dior-
ganotin(IV) complexes [31,32]. While the values of
complexes 9 and 10 are ꢁ81, ꢁ129 ppm at 298 K,
and ꢁ123, ꢁ229 ppm at 195 K, respectively, which
indicated that complexes 9 and 10 are rather tempera-
ture-dependent than the complexes 8 and 11, and the
For methyl derivatives 4 and 8, substitution of
2J(119Sn–1H) values (72 and 80 Hz, respectively) and
1J(119Sn–13C) values (490 and 546 Hz, respectively) into
the corresponding Lockhart–Marders equations [22–24]
(empirical relationship between the coupling constants
and the C–Sn–C angle) gives C–Sn–C angle values of
121ꢁ and 119ꢁ for complex 4 and 130ꢁ and 124ꢁ for com-
plex 8, respectively. These angles values might suggest
that in solution the dimethyltin derivative 4 is a dis-
torted trigonal bipyramid, while complex 8 is a skew-
trapezoidal bipyramid and the basic features of the
solid-state phase remain in CDCl3 solution.
As reported in literatures [25], values of d (119Sn) in
the ranges ꢁ210 to ꢁ400, ꢁ90 to ꢁ190 and 200 to ꢁ60
ppm have been associated with six-, five- and four-co-
ordinate tin centers, respectively. On this base, the
119Sn NMR spectra of triorganotin (IV) derivatives 1–
3 show one broad sharp signal and show rather temper-
ature-dependent. The d values found (ꢁ57, ꢁ55 and
ꢁ51 ppm at 298 K and lower values at 195 K, ꢁ87,
ꢁ85 and ꢁ80 ppm, respectively) are consistent with a
tetrahedral and monomeric structure caused by the
weaker Sn–N bonds. Besides, the 119Sn NMR chemical

C. Ma et al. / Journal of Organometallic Chemistry 690 (2005) 519–533
525
Table 4
Crystal, data collection and structure refinement parameters of complexes 8–11
Complexes
8
9
10
11
Empirical formula
Formula weight
˚
Wavelength (A)
C12H16N4S2Sn
399.10
0.71073
C18H28N4S2Sn
483.25
0.71073
C22H20N4S2Sn
523.23
0.71073
C24H24N4S2Sn
551.28
0.71073
Crystal system
Space group
Orthorhombic
Cmc21
7.582(4)
Monoclinic
P21/n
6.178(7)
Monoclinic
P21/n
9.933(3)
Orthorhombic
Pna21
˚
a (A)
11.350(12)
11.550(12)
18.629(20)
90
˚
b (A)
17.751(8)
12.063(6)
90
43.14(5)
16.626(6)
14.388(5)
˚
c (A)
8.774(10)
99.324(16)
2307(4)
a (ꢁ)
108.390(5)
2255.0(13)
4
3
˚
V (A )
1623.5(13)
4
1.633
2442(4)
4
1.499
Z
4
1.391
Dcalc (g mꢁ3
F(000)
)
1.541
1048
1.334
792
1.823
984
1.296
1112
1.236
l (mmꢁ1
)
Crystal size (mm)
h Range
Index ranges
0.42 · 0.23 · 0.20
2.29–25.02
ꢁ9 6 h 6 8;
ꢁ17 6 k 6 l21;
ꢁ14 6 l 6 14
4230
0.46 · 0.110.09
1.89–25.03
ꢁ7 6 h 6 7;
ꢁ32 6 k 6 51;
ꢁ10 6 l 6 10
11228
0.32 · 0.25 · 0.17
1.93–25.02
ꢁ11 6 h 6 11;
ꢁ12 6 k 6 19;
ꢁ17 6 l 6 16
11753
0.41 · 0.34 · 0.02
2.07–25.03
ꢁ13 6 h 6 13;
ꢁ13 6 k 6 12;
ꢁ22 6 l 6 14
12207
Reflections collected
Unique reflections
Absorbtion correction
1515(Rint = 0.0292)
Semi-empirical
from equivalents
0.7119, 0.5147
3835(Rint = 0.051)
Semi-empirical
from equivalents
0.8923, 0.5670
3835,10, 226
1.028
3981(Rint = 0.0622)
Semi-empirical
from equivalents
0.8050, 0.6749
3981, 0, 262
0.829
3340(Rint = 0.0297)
Semi-empirical
from equivalents
0.9793, 0.6313
3340, 1, 280
1.014
Max/min transmission
Data, restrainst, parameters 1515, 1, 112
GOF
0.907
Final R indices [I > 2r(I)]
R indices (all data)
Largest difference peak,
R1 = 0.0264, wR2 = 0.0527 R1 = 0.0667 wR2 = 0.1383
R1 = 0.0394 wR2 = 0.0639
R1 = 0.0263, wR2 = 0.0629
R1 = 0.0331, wR2 = 0.0542 R1 = 0.1096, wR2 = 0.1552 R1 = 0.0810, wR2 = 0.0728 R1 = 0.0335, wR2 = 0.0670
0.526, ꢁ0.180 0.623, ꢁ0.856 0.820, ꢁ0.426 0.561, ꢁ0.260
ꢁ3
˚
hole (e A
)
Sn–N bonds are probably dissociated with increase of
the temperature.
range reported for triphenyltin heteroarenethiolates
˚
(2.405–2.481 A) and approach the sum of the covalent
˚
radii of tin and sulfur (2.42 A) [33,34], which prove that
sulfur atoms coordinated to tin atom by strong covalent
bonds. Besides, the Sn–N distance is little longer than
˚
that of complex Ph3Sn(Me2Pymt) (2.835(7) A) [11],
but still shorter than the sum of the van der Waals radii
˚
of tin and nitrogen (3.74 A) [35]. So it can be regarded as
a weak coordination bond. In contrast, for complex 2,
the Sn(1)–S(1) bond length and the Sn(1)–N(1) distance
From our NMR data for all complexes and following
structural studied, we conclude that the nitrogen ligand
is labile and hence that the mechanism of interaction of
organotin complexes in biological systems differs from
that of platinum complexes which retain the Pt–N bonds
when reacting with DNA. In organotin compounds the
Sn–N bonds are probably cleaved before the tin reaches
its ultimate target.
˚
are 2.455(2) and 2.885(5) A, all of them are similar to
those of complex 1.
3.2. Description of crystal structures
Including the tin–nitrogen interaction [36], the geom-
etry at Sn in complexes 1 and 2 becomes distorted trig-
onal bipyramidal with the axial–tin–axial angles N(2)–
Sn(1)–C(12) of 155.50(14)ꢁ for complex 1 and N(1)–
Sn(1)–C(20) of 158.45(15)ꢁ for complex 2, respectively.
It is worth to note that in tri–organotin complexes,
the coordination mode B is preferred to be selected than
the mode A because of the stereo-constraints of tri-alkyl
and this is the case of the complex 2, as shown in Fig. 4.
However, to our surprise, we find that the ligand choose
the coordination mode A in complex 1 irrespective of the
steric hindrance, as shown in Fig. 2, which maybe attri-
bute to the ring-stacking interactions. The orientation is
3.2.1. Ph3Sn(SC5H5N2) (1) and (PhCH2)3Sn(SC5H5N2)
(2)
Selected bond lengths and bond angles for 1 and 2 are
given in Table 5 and their molecular structures and the
packing of cell units of complexes 1 and 2 are shown
in Fig. 2–5, respectively.
The four primary bonds to Sn in 1 are to three phenyl
˚
groups [Sn–C between 2.135(4) and 2.152(5) A] and to S
˚
[Sn(1)–S(1) distance 2.4228(16) A], in addition there is a
weak intramolecular Sn–N interaction [Sn(1)–N(2) dis-
˚
tance 2.907(4) A], thus providing a 4-membered chelate
ring. The Sn–S bond length in 1 lies in the middle of the

526
C. Ma et al. / Journal of Organometallic Chemistry 690 (2005) 519–533
Table 5
Selected bond lengths and angles for the complexes 1 and 2
Complex 1
Complex 2
Bond
˚
Distance (A)
˚
Distance (A)
Bond
Sn(1)–C(18)
Sn(1)–C(6)
Sn(1)–C(12)
Sn(1)–S(1)
Sn(1)–N(2)
S(1)–C(1)
2.135(4)
2.136(5)
2.152(5)
2.4228(16)
2.907(4)
1.755(5)
Sn(1)–C(13)
Sn(1)–C(6)
Sn(1)–C(20)
Sn(1)–S(1)
Sn(1)–N(1)
S(1)–C(1)
2.151(5)
2.152(5)
2.174(5)
2.455(2)
2.885(5)
1.763(5)
Angle
Amplitude (ꢁ)
Angle
Amplitude (ꢁ)
C(18)–Sn(1)–C(6)
C(18)–Sn(1)–C(12)
C(6)–Sn(1)–C(12)
C(18)–Sn(1)–S(1)
C(6)–Sn(1)–S(1)
C(12)–Sn(1)–S(1)
C(18)–Sn(1)–N(2)
C(6)–Sn(1)–N(2)
C(12)–Sn(1)–N(2)
S(1)–Sn(1)–N(2)
110.19(17)
107.65(16)
109.74(16)
117.06(12)
113.79(12)
97.34(12)
85.42(14)
83.67(14)
155.50(14)
58.17(8)
C(13)–Sn(1)–C(6)
C(13)–Sn(1)–C(20)
C(6)–Sn(1)–C(20)
C(13)–Sn(1)–S(1)
C(6)–Sn(1)–S(1)
C(20)–Sn(1)–S (1)
C(13) –Sn(1)–N(1)
C(6)–Sn(1)–N(1)
C(20)–Sn(1)–N(1)
S(1)–Sn(1)–N(1)
116.86(19)
107.34(19)
108.8(2)
113.93(15)
108.77(14)
99.62(15)
81.73(15)
82.87(18)
158.45(15)
58.98(10)
Fig. 2. Molecular structure of complex 1.
Fig. 4. Molecular structure of complex 2.
such that each mpymt group is arranged face-to-face at
˚
a distance of 3.369 A and shows significant p–p stacking
interactions [37,38]. Furthermore, CH–p interactions
between the Ph ring and the C-4 methyl group of the lig-
and also stabilize the structure, the distances
C(5)ꢀ ꢀ ꢀC(16), C(5)ꢀ ꢀ ꢀC(17) and C(5)ꢀ ꢀ ꢀC(12) are 3.776,
˚
3.788 and 4.705 A, respectively [39].
3.2.2. Me2SnCl(SC5H5N2) (4), Ph2SnCl(SC5H5N2)
(5) and (PhCH2)2SnCl(SC5H5N2) (7)
Selected bond lengths and bond angles for 4, 5 and 7
are given in Table 6–8, respectively. The molecular
structures and unit cells of 4, 5 and 7 are shown in
Fig. 6–11, respectively.
Fig. 3. The unit cell of complex 1.

C. Ma et al. / Journal of Organometallic Chemistry 690 (2005) 519–533
527
Different from those triorganotin chlorides, diorgan-
otin dichlorides have two chlorine atoms that can be
substituted. When diorganotin dichlorides react with
Hmpymt in 1:1 molar ratio, one chlorine atom still re-
mained, as shown in Figs. 6, 8 and 10, respectively.
However, due to inter and/or intra-molecular interac-
tions and steric requriements, the coordination mode
of the ligand is different between complexes 4, 5 and
complex 7.
For complex 4, the coordination geometry about
Sn(IV) is a distorted trigonal bipyramid in which two
carbon atoms of two methyl groups and a sulfur atom
form the equatorial plane, the sum of the trigonal plane
angles is 354.4ꢁ, while one nitrogen atom and one halo-
gen atom occupy the axial site [Cl(1)–Sn(1)–N(1)
153.9(3)ꢁ ]. In this way the ligand behaves as a bidentate
species and chelates the tin atom by means of the niro-
gen and the thiolato sulfur. The consequence formation
of a four member ring with a S(1)–Sn(1)–N(1) bite angle
˚
63.5(3)ꢁ. The Sn(1)–Cl(1) distance (2.454(4) A) lies in the
range of the covalent radii (2.37–2.60 A) [40]. The
˚
Fig. 5. The unit cell of complex 2.
Table 6
Selected bond lengths and angles for the complex 4
˚
Distance (A)
˚
Distance (A)
Bond
Bond
Sn(1)–C(6)
Sn(1)–C(6)#1
Sn(1)–Cl(1)
S(1)–C(1)
2.122(10)
2.122(10)
2.454(4)
Sn(1)–S(1)
Sn(1)–N (1)
Sn(1)ꢀ ꢀ ꢀCl(1A)
2.459(4)
2.509(11)
3.959
1.758(12)
Angle
Amplitude (ꢁ)
Angle
Amplitude (ꢁ)
C(6)–Sn(1)–C(6)#1
C(6)–Sn(1)–Cl(1)
123.4(6)
101.4(3)
101.4(3)
115.5(3)
115.5(3)
101.8
Cl(1)–Sn(1)–S(1)
C(6)–Sn(1)–N(1)
C(6)#1–Sn(1)–N(1)
Cl(1)–Sn(1)–N(1)
S(1)–Sn(1)–N(1)
90.44(13)
90.7(3)
90.7(3)
C(6)#1–Sn(1)–Cl(1)
C(6)–Sn(1)–S (1)
153.9(3)
63.5(3)
C(6)#1–Sn(1)–S (1)
Sn(1)–Cl(1)ꢀ ꢀ ꢀSn(1A)
Table 7
Selected bond lengths and angles for the complexes 5
Molecule A
Molecule B
Bond
˚
Distance (A)
˚
Distance (A)
Bond
Sn(1)–C(12)
Sn(1)–S(1)
Sn(1)–N(1)
Sn(1)–C(6)
Sn(1)–Cl(1)
S(1)–C (1)
2.116(8)
2.418(2)
2.483(5)
2.141(6)
2.4215(18)
1.743(6)
Sn(2)–C(29)
Sn(2)–S(2)
Sn(2)–N(3)
Sn(2)–C(23)
Sn(2)–Cl(2)
S(2)–C(18)
2.113(7)
2.423(2)
2.456(5)
2.108(5)
2.4307(17)
1.746(6)
Angle
Amplitude (ꢁ)
Angle
Amplitude (ꢁ)
C(12)–Sn(1)–C(6)
C(12)–Sn(1)–S(1)
C(6)–Sn(1)–S(1)
C(12)–Sn(1)–Cl(1)
C(6)–Sn(1)–Cl(1)
C(12)–Sn(1)–N(1)
S(1)–Sn(1)–N(1)
S(1)–Sn(1)–Cl(1)
C(6)–Sn(1)–N(1)
Cl(1)–Sn(1)–N(1)
114.5(2)
122.7(2)
118.30(17)
99.91(17)
99.43(15)
95.0(3)
C(23)–Sn(2)–C(29)
C(23)–Sn(2)–S(2)
C(29)–Sn(2)–S(2)
C(23)–Sn(2)–Cl(2)
C(29)–Sn(2)–Cl(2)
C(23)–Sn(2)–N(3)
S(1)–Sn(2)–N(1)
S(2)–Sn(2)–Cl(2)
C(29)–Sn(2)–N(3)
Cl(1)–Sn(1)–N(1)
126.6(3)
116.07(18)
113.93(19)
97.91(16)
97.68(17)
93.1(2)
64.08(13)
92.11(7)
91.1(2)
64.27(15)
92.18(7)
92.2(3)
156.13(15)
156.45(17)

528
C. Ma et al. / Journal of Organometallic Chemistry 690 (2005) 519–533
Table 8
Selected bond lengths and angles for the complex 7
˚
Distance (A)
˚
Distance (A)
Bond
Bond
Sn(1)–C(6)
Sn(1)–C(6)#1
Sn(1)–Cl(1)
Sn(1)–S(1)
2.144(4)
2.144(4)
2.424(3)
2.480(3)
Sn(1)–N(1)
S(1)–C(1)
Snꢀ ꢀ ꢀN
2.664(5)
1.731(5)
2.804
Snꢀ ꢀ ꢀS
3.672
Angle
Amplitude (ꢁ)
Angle
Amplitude (ꢁ)
C(6)–Sn(1)–C(6)#1
C(6)–Sn(1)–Cl(1)
C(6)#1–Sn(1)–Cl(1)
C(6)–Sn(1)–S(1)
143.1(2)
C(6)–Sn(1)–N(1)
88.27(12)
88.27(12)
149.05(11)
60.61(9)
45.89
100.83(12)
100.83(12)
105.06(11)
105.06(11)
88.44(6)
C(6)#1–Sn(1)–N(1)
Cl(1)–Sn(1)–N(1)
S(1)–Sn(1)–N(1)
C(6)#1–Sn(1)–S(1)
Cl(1)–Sn(1)–S(1)
S(1A)ꢀ ꢀ ꢀSn(1)ꢀ ꢀ ꢀN(3A)
Fig. 6. Molecular structure of complex 4.
Fig. 9. The unit cell of complex 5.
Fig. 7. The unit cell of complex 4.
Fig. 8. Molecular structure of complex 5.
Fig. 10. Molecular structure of complex 7.

C. Ma et al. / Journal of Organometallic Chemistry 690 (2005) 519–533
529
mode B in complexes 4 and 5, while it adopts mode A to
bond to tin atom in complex 7 (see Fig. 10).
Furthermore, complex 4 is a dimer bridged by weak
Snꢀ ꢀ ꢀCl intermolecular interactions between the two
˚
closest molecules. The Snꢀ ꢀ ꢀCl distance is 3.959 A, just
comparable to the sum of the van der Waalsꢀ radii of
˚
Sn and Cl (4.0 A) [44]. The form of the dimer maybe
the reason that the ligand adopts mode B to bond to
tin atom in complex 4. But the reason that the ligand
adopts mode B to bond to tin atom in complex 5 is
the large of stereo-constraint functions of phenyl groups
and two dependent molecules. While complex 7 is a one-
dimensional chain bridged by both intermolecular
Snꢀ ꢀ ꢀS and Snꢀ ꢀ ꢀN contacts between the neighboring
molecules. In which both the coordinated 2-sulfur atom
and no-coordinated 3-nitrogen atom of the mpymt lig-
and bond to tin atom of neighboring molecules. The
Fig. 11. Perspective view showing the 1D ribbon of the complex 7.
˚
Sn(1)–S(1) distance 2.459(4) A, approach the covalent
˚
radii of Sn and S (2.42 A) [34]. The Sn(1)–N(1) distance
˚
2.509(11) A, is consistent with that of [2-
˚
Snꢀ ꢀ ꢀN distance (2.804 A) is consistent with that of dib-
˚
utyltin derivatives of 2-mercaptobenzoxazole [2.81(1) A]
˚
(Me2NCH2)C6H4]SnPh2Cl [2.519(2) A] [40].
[45], and still shorter than the sum of the van der Waals
˚
˚
tance (3.672 A) lies within the sum of the van der waals
For complex 5, as shown in Fig. 8, which contains
two crystallographically independent molecules a and
b. And the conformations of the two molecules are al-
most the same, only with little differences in bond
lengths and bond angles (see Table 7). Both of the coor-
dination geometries about Sn(IV) atoms are distorted
trigonal bipyramid, similar to that of complex 4. In
which two phenyl groups and a sulfur atom form the
equatorial plane, while the halogen and the nitrogen oc-
cupy the apical positions. The Sn–Cl distances are
radii of tin and nitrogen (3.74 A) [35]. The Snꢀ ꢀ ꢀS dis-
˚
radii of Sn and S (4.0 A) [34]. Besides, the stereo-
constraints of Cl– group is smaller than that of
PhCH2– group in complex 2, which maybe benefit the
coordination of 3-nitrogen atoms. All above informa-
tion indicates that it is the stereo-constraints, intermo-
lecular interactions and crystal packing requirements
that lead the ligand to adopt different coordination
modes to bond to tin in complexes 4, 5 and 7.
˚
2.4215(18) and 2.4307(17) A, lies in the range (2.32–
˚
2.58 A) of Sn–Cl distances found in chloroorganotin
3.2.3. Me2Sn(SC5H5N2)2 (8), (n-Bu)2Sn(SC5H5N2)2 (9),
Ph2Sn(SC5H5N2)2 (10) and (PhCH2)2Sn- (SC5H5N2)2
(11)
Selected bond lengths and bond angles for 8, 9, 10
and 11 are given in Tables 9–12, respectively. The molec-
ular structures of 8, 9, 10 and 11 are shown in Fig. 12–
15, respectively.
For complex 8, the tin atom is coordinated to two
methyl groups and to two sulfur atoms from two deprot-
˚
onated ligands (mpymt). The Sn–C distance 2.102(5) A
˚
and the Sn–S distances [2.480(2) and 2.484(3) A] are
similar to those found in [SnMe2(Spym)2] [2.17(1)–
˚
2.25(1) and 2.466(4) A, respectively] [46]. The Sn–S dis-
tances are close to the typical length of a single covalent
bond. Due to the steric effect, the Sn–N distances
˚
[2.650(7) and 2.752(6) A] are longer than those of com-
(IV) complexes in general [41,42]. The Sn–S distances
˚
are 2.418(2) and 2.423(2) A, shorter than those of
˚
Ph2SnCl(MBT) (2.485(22) A) [43]. The Sn–N bond
˚
lengths are 2.483(5) and 2.456(5) A, the bite angles
N(1)–Sn(1)–S(1) 64.08(13)ꢁ and N(3)–Sn(2)–S(2)
64.27(15)ꢁ. All above of which are similar to those of
complex 4.
As far as complex 7 is concerned, the environment of
tin is similar to that of complex 5 except for the coordi-
nation mode of mpymt ligand, in which the ligand
adopts mode A to bond to tin atom. The geometry of
Sn is also a distorted cis-trigonal bipyramidal with one
nitrogen atom and one halogen atom in axial sites
[Cl(1)–Sn(1)–N(1) 149.05(11)ꢁ], and one sulfur and two
benzenyl C atoms occupying the equatorial plane
[C(6)#1–Sn(1)–C(6)
105.06(11)ꢁ, C(6)#1–Sn(1)–S(1) 105.06(11)ꢁ]. The
Sn(1)–Cl(1) distance 2.424(3) A, Sn(1)–N(2) distance
143.1(2)ꢁ,
C(6)–Sn(1)–S(1)
plex 4, so they can be regarded as weak intramolecular
interactions, but they are shorter than those found in
˚
[SnMe2(Spym)2] (2.83(2) A) [46]. The bite angles S(1)–
Sn(1)–N(1), S(2)–Sn(1)–N(4) of complex 8 [60.28(18)ꢁ
and 61.35(18)ꢁ, respectively] are reconcilable with
skew-trapezoidal bipyramid geometry. This geometry
can also be considered as a distorted trans regular octa-
˚
˚
˚
2.664(5) A, and the Sn(1)–S(1) distance 2.480(3) A, the
bite angle N(1)–Sn(1)–S(1) 60.61(9)ꢁ, are all consistent
with those of complex 5.
It is worth to note that the ligand adopts different
coordination mode to bond to tin atom in complexes
4, 5 and 7. As shown in Figs. 6 and 8, the ligand adopts
˚
hedron. The S–C distances [1.773(9) and 1.782(15) A]
are consistent with single-bond character [47].

530
C. Ma et al. / Journal of Organometallic Chemistry 690 (2005) 519–533
Table 9
Selected bond lengths and angles for the complex 8
˚
Distance (A)
˚
Distance (A)
Bond
Bond
Sn(1)–C(11)#1
Sn(1)–C(11)
Sn(1)–S(1)
2.102(5)
2.102(5)
2.480(2)
1.773(9)
Sn(1)–S(2)
Sn(1)–N(4)
Sn(1)–N(1)
S(2)–C(6)
2.484(3)
2.650(7)
2.752(6)
1.782(15)
S(1)–C(1)
Angle
Amplitude (ꢁ)
Angle
Amplitude (ꢁ)
C(11)#1–Sn(1)–C(11)
C(11)–Sn(1)–S(1)
C(11)#1–Sn(1)–S(2)
C(11)–Sn(1)–S(2)
S(1)–Sn(1)–S(2)
127.0(3)
S(2)–Sn(1)–N(4)
C(11)–Sn(1)–N(1)
S(1)–Sn(1)–N(1)
S(2)–Sn(1)–N(1)
N(4)–Sn(1)–N(1)
S(1)–Sn(1)–N(4)
61.35(18)
82.71(13)
60.28(18)
148.9(2)
107.95(12)
109.23(12)
109.23(12)
88.64(9)
149.7(2)
149.99(16)
C(11)#1–Sn(1)–N(4)
C(11)–Sn(1)–N(4)
83.93(12)
83.93(12)
Table 10
Selected bond lengths and angles for the complex 9
˚
Distance (A)
˚
Distance (A)
Bond
Bond
Sn(1)–C(17)
Sn(1)–C(11)
Sn(1)–S(2)
Sn(1)–S(1)
2.115(5)
2.124(4)
Sn(1)–N(3)
Sn(1)–N(1)
S(1)–C(1)
S(2)–C(6)
2.700(4)
2.933(4)
1.762(5)
1.745(5)
2.4502(14)
2.4753(15)
Angle
Amplitude (ꢁ)
Angle
Amplitude (ꢁ)
C(17)–Sn(1)–C(11)
C(17)–Sn(1)–S(2)
C(11)–Sn(1)–S(2)
C(17)–Sn(1)–S(1)
C(11)–Sn(1)–S(1)
S(2)–Sn(1)–S(1)
122.27(19)
113.30(12)
109.70(14)
108.09(15)
112.06(13)
85.36(5)
S(2)–Sn(1)–N(3)
S(1)–Sn(1)–N(3)
C(17)–Sn(1)–N(1)
C(11)–Sn(1)–N(1)
S(2)–Sn(1)–N(1)
S(1)–Sn(1)–N(1)
N(3)–Sn(1)–N(1)
60.57(9)
145.75(9)
83.81(14)
84.64(15)
142.63(10)
57.37(9)
C(17)–Sn(1)–N(3)
C(11)–Sn(1)–N(3)
84.40(15)
84.88(14)
156.80(13)
Table 11
Selected bond lengths and angles for the complex 10
˚
Distance (A)
˚
Distance (A)
Bond
Bond
Sn(1)–C(11)
Sn(1)–C(15)
Sn(1)–S(1)
Sn(1)–S(2)
2.046(14)
2.242(16)
2.477(5)
2.482(4)
Sn(1)–N(3)
Sn(1)–N(1)
S(1)–C(1)
S(2)–C(6)
2.782(10)
2.889(11)
1.749(9)
1.759(12)
Angle
Amplitude (ꢁ)
Angle
Amplitude (ꢁ)
C(11)–Sn(1)–C(15)
C(11)–Sn(1)–S(1)
C(15)–Sn(1)–S(1)
C(11)–Sn(1)–S(2)
C(15)–Sn(1)–S(2)
S(1)–Sn(1)–S(2)
131.7(7)
111.3(4)
104.8(6)
109.1(4)
104.5(6)
85.80(15)
85.8(5)
S(1)–Sn(1)–N(3)
S(2)–Sn(1)–N(3)
C(11)–Sn(1)–N(1)
C(15)–Sn(1)–N(1)
S(1)–Sn(1)–N(1)
S(2)–Sn(1)–N(1)
N(3)–Sn(1)–N(1)
144.9(2)
59.3(2)
85.1(5)
86.9(5)
59.2(2)
145.0(2)
155.6(3)
C(11)–Sn(1)–N(3)
C(15)–Sn(1)–N(3)
82.4(5)
The crystal structure of 8 shows ring-stacking interac-
tions, each mpymt group is arranged face-to-face at dis-
that lead the mpymt in complex 8 to adopt both the
N(1)/S2 and S2/N(3) coordination modes.
˚
tances of 4.161 and 4.227 A, respectively; and show p–
stacking interactions [46]. As shown in Fig. 12, steric
For three complexes 9, 10 and 11, compare to complex
8, the mpymt ligand adopts only the remote linkage form
B: N(1)/S2 coordination mode, which is also attributed to
requirements and p–p interactions maybe the reasons

C. Ma et al. / Journal of Organometallic Chemistry 690 (2005) 519–533
531
Table 12
Selected bond lengths and angles for the complex 11
˚
Distance (A)
˚
Distance (A)
Bond
Bond
Sn(1)–C(11)
Sn(1)–C(18)
Sn(1)–S(1)
Sn(1)–S(2)
2.148(5)
2.193(5)
2.513(2)
2.526(2)
Sn(1)–N(1)
Sn(1)–N(3)
S(1)–C(1)
S(2)–C(6)
2.583(4)
2.752(5)
1.760(5)
1.745(5)
Angle
Amplitude (ꢁ)
Angle
Amplitude (ꢁ)
C(11)–Sn(1)–C(18)
C(11)–Sn(1)–S(1)
C(18)–Sn(1)–S(1)
C(11)–Sn(1)–S(2)
C(18)–Sn(1)–S(2)
S(1)–Sn(1)–S(2)
137.24(19)
109.96(16)
106.51(15)
105.06(15)
98.56(13)
86.59(9)
S(1)–Sn(1)–N(1)
S(2)–Sn(1)–N(1)
C(11)–Sn(1)–N(3)
C(18)–Sn(1)–N(3)
S(1)–Sn(1)–N(3)
S(2)–Sn(1)–N(3)
N(1)–Sn(1)–N(3)
61.53(10)
148.12(9)
81.31(19)
80.77(17)
146.10(10)
59.51(11)
152.38(13)
C(11)–Sn(1)–N(1)
C(18)–Sn(1)–N(1)
87.33(18)
91.01(16)
Fig. 12. Molecular structure of complex 8.
Fig. 14. Molecular structure of complex 10.
Fig. 13. Molecular structure of complex 9.
Fig. 15. Molecular structure of complex 11.
the stereo-constraints. In each case, two carbons and two
sulfur atoms are covalently linked to the metal. The va-
lence extension is performed via the nitrogen atoms,
N1 and N3 of the Hmpymt ligand. The two chelating sul-
fur occupy cis positions. The Sn–C distances [from
respectively] are similar to those found in other
[SnR2(chelate)2] systems [11,48,49]. Three complexes
are different distinctly from each other with regard to
their weak intramolecular Sn–N interactions [2.825(7)
˚
2.092(9) to 2.193(5) A], are quite close to those found
˚
in Bu2Sn(mbo)2 [2.09(2) and 2.19(3) A]. The Sn–S dis-
˚
tances [2.466(3) and 2.474(3) A for 9, 2.4502(14) and
˚
˚
and 2.844(7) A for 9, 2.700(4) and 2.933(4) A for 10,
˚
2.583(4) and 2.752(5) A for 11, respectively], they are
all longer than the sum of the covalent radii of tin and
˚
2.4753(15) A for 10, 2.513(2) and 2.526(2) A for 11,
˚

532
C. Ma et al. / Journal of Organometallic Chemistry 690 (2005) 519–533
˚
nitrogen atoms (2.15 A), but still lie within the sum of the
˚
van der Waals radii of the two atoms (3.74 A) [35]. The
(Fax: +44 1223 336033; e-mail: deposit@ccdc.cam.ac.uk
or www:http://www.ccdc.cam.ac.ck).
geometries of complexes 9, 10 and 11 can also be consid-
ered as distorted trans regular octahedrons. The S–C dis-
˚
tances [from 1.725(8) to 1.762(5) A] are consistent with
those found in complex 8.
Acknowledgement
Besides, for complex 11, similar to complex 7, also
contains one-dimensional chain bridged by weak
Snꢀ ꢀ ꢀS intermolecular interactions between the neigh-
The authors thank the National Natural Science
Foundation of China (20271025) and the Natural Sci-
ence Foundation of Shandong Province for financial
support.
˚
boring molecules. The Snꢀ ꢀ ꢀS distance (3.774 A), is
consistent with that of complex 7 and also shorter
than the sum of the van der waals radii of Sn and S
˚
(4.0 A) [34].
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