Synthesis and spectroscopic properties of [N-(4-carboxyphenyl) salicylideneiminato] di- and tri-organotin (IV) complexes and crystal structures of {[nBu2Sn(2-OHC6H4CH=NC 6H4COO)]2O}2 and Ph 3Sn(2-OHC6H4CH=NC6H4COO)

Article abstract of DOI:10.1016/j.jorganchem.2004.09.063

Reactions of R₂SnO (R: ⁿBu, Cy, Ph, PhCH₂) and R₃SnCl (R: Ph, Cy, PhCH₂, 2-Cl-PhCH₂, 4-F-PhCH₂, 4-Cl-PhCH₂) with N-(4-carboxyphenyl)- salicylideneimine (LH₂) in 1:1 stoichiometry afford complexes {[R₂Sn(LH)]₂O}₂ and R₃Sn(LH). These complexes have been characterized by elemental analyses, IR, ¹H and ¹¹⁹Sn NMR spectroscopy. The crystal structures of {[ ⁿBu₂Sn(LH)]₂O}₂, 1 and Ph ₃Sn(L), 5 are determined by single crystal X-ray diffraction. Results showed that in the solid state the complex 1 is a tetranuclear centrosymmetric dimer with six-coordination being assigned to both the endo-cyclic and exo-cyclic tin atoms after consideration of close intermolecular tin oxygen contacts, and study show that the imino nitrogen atom do not participate in coordination to the tin atom. The complex 5 is a monomer, and in the molecule the tin atoms are five-coordinated in trigonal bipyramidal geometries with the two oxygen atom of the carboxylate both coordinating to the tin atoms.

Full text of DOI:10.1016/j.jorganchem.2004.09.063

Journal of Organometallic Chemistry 690 (2005) 435–440
www.elsevier.com/locate/jorganchem
Synthesis and spectroscopic properties of [N-(4-carboxyphenyl)
salicylideneiminato] di- and tri-organotin (IV) complexes and
crystal structures of {[nBu2Sn(2-OHC6H4CH@NC6H4COO)]2O}2
and Ph3Sn(2-OHC6H4CH@NC6H4COO)
*
Han Dong Yin , Qi Bao Wang, Sheng Cai Xue
Department of Chemistry, Liaocheng University, Liaocheng 252059, China
Received 29 August 2004; accepted 27 September 2004
Available online 28 October 2004
Abstract
n
Reactions of R2SnO (R: Bu, Cy, Ph, PhCH2) and R3SnCl (R: Ph, Cy, PhCH2, 2-Cl-PhCH2, 4-F-PhCH2, 4-Cl-PhCH2) with N-
(4-carboxyphenyl)-salicylideneimine (LH2) in 1:1 stoichiometry afford complexes {[R2Sn(LH)]2O}2 and R3Sn(LH). These complexes
have been characterized by elemental analyses, IR, 1H and 119Sn NMR spectroscopy. The crystal structures of {[nBu2Sn(LH)]2O}2, 1
and Ph3Sn(L), 5 are determined by single crystal X-ray diffraction. Results showed that in the solid state the complex 1 is a tetra-
nuclear centrosymmetric dimer with six-coordination being assigned to both the endo-cyclic and exo-cyclic tin atoms after consid-
eration of close intermolecular tin oxygen contacts, and study show that the imino nitrogen atom do not participate in coordination
to the tin atom. The complex 5 is a monomer, and in the molecule the tin atoms are five-coordinated in trigonal bipyramidal geom-
etries with the two oxygen atom of the carboxylate both coordinating to the tin atoms.
ꢀ 2004 Published by Elsevier B.V.
Keywords: Organotin (IV) complex; Schiff base; Synthesis; Crystal structure
1. Introduction
N-arylidene-x-amino acids are mostly features one-di-
mensional chain polymeric structure with the carboxy-
late group bridging both the intra- and inter-
molecular tin atoms [15]. As an extension of these
studies, we synthesized another ten new di- and tri-
organotin (IV) complexes of N-(4-carboxyphenyl) sali-
cylideneiminato with quite different coordination
modes. X-ray studies show that complex 1 exhibits a
centrosymmetric dimeric structure with an Sn2O2 core,
while complex 5 confrorm to monomeric structure with
the carboxylate group bidentate coordinating to the
central tin atom. Noteworthy in both structures is the
absence of the significant contact between the tin atoms
and the imino nitrogen atoms. All the ten complexes
Organotin(IV) complexes with Schiff bases have been
the focus all the while owing to their anti-tumour activ-
ities [1–8], in particular organotin(IV) esters of N-
arylidene-amino acids have been observed to exhibit a
great anti-tumour activity against human tumour cell
lines [9]. Recently studies on the coordination chemistry
of amio-acid-derived Schiff bases ligating diorgano-
tin(IV) centers have received some attention [10]. Previ-
ous studies have shown that the mode of coordination
of the Schiff bases in diorganotin(IV) complexes are
mostly tridentate [11–13], including the four complexes
we have reported [14]. And triorganotin(IV) esters of
1
have been characterized by elemental analyses, IR, H
and 119Sn NMR spectra, and the results of this study
are reported herein.
*
Corresponding author. Tel./fax: +866358238121.
E-mail address: handongyin@sohu.com (H.D. Yin).
0022-328X/$ - see front matter ꢀ 2004 Published by Elsevier B.V.
doi:10.1016/j.jorganchem.2004.09.063

436
H.D. Yin et al. / Journal of Organometallic Chemistry 690 (2005) 435–440
HO
HC
OH
CH N
2. Experimental
COOH
)]2O}2
N
+
{[R2Sn(OOC
R2SnO
R= n-C4H9- (1), Cy- (2), C6H5- (3), C6H5CH2- (4)
2.1. Materials and methods
HO
HC
OH
CH N
Et3N
Diorganotin oxides were commercially available and
used without further purification, and triorganotin chlo-
rindes were prepared by the method described in the lit-
erature [16]. The melting points were obtained with
Kolfer micro melting point apparatus and were uncor-
rected. IR spectra were recorded on a Nicolet-460 spec-
trophotometer using KBr discs and sodium chloride
COOH
+
R3SnOOC
N
R3SnCl
R= C6H5- (5), Cy- (6), C6H5CH2- (7), 2-ClC6H4CH2- (8), 4-FC6H4CH2- (9),
4-ClC6H4CH2- (10)
Scheme 2.
24.65%. 1H NMR (CDCl3): 13.02 (4H, d, Ar–OH),
8.68(4H, d, N@CAH), 8.11(8H, d, H(a)), 7.43(8H, d,
H(b)), 6.96–7.41(16H, m, Ar–H), 1.25–1.82(48H, m,
Sn–(CH2)3–), 0.78–0.97(24H, m, CH3); 119Sn NMR
(CDCl3): À230.5, À209.6; IR (KBr): m(OH), 3419
1
optics. H and 119Sn NMR spectra were recorded on a
Mercury Plus-400 NMR spectrometer, chemical shifts
were given in ppm relative to Me4Si and Me4Sn in
CDCl3 solvent. Elemental analyses were performed in
a PE-2400 II elemental analyzer, and tin was estimated
as SnO2.
cmÀ1
, , mas(COO), 1596,1570,
m(C@N), 1620 cmÀ1
ms(COO), 1416, 1399 cmÀ1, m(Sn–O–Sn), 635 cmÀ1
,
m(Sn–C), 545 cmÀ1, m(Sn–O), 421 cmÀ1
.
2.2. Preparation of the ligand
2.3.2. {[Cy2Sn(LH)]2O}2 (2)
An ethanol solution of salicylidene (10.5, 0.1 ml) was
added slowly to an ethanol solution containing p-amin-
obezoic acid (13.7 g, 0.1 mol) under stirring for about 15
min, and the crude product was precipitated. This was
washed thoroughly with petroleum ether and recrystal-
lized from methanol to yield pure LH2 22.4 g. Yield
93%. M.p. 193 ꢁC (dec.) (see Scheme 1).
Orange crystals 0.437 g, yield 82%. M.p. 160–161 ꢁC.
Anal. Calc. for C104H128N4O14Sn4: C, 58.56; H, 6.05; N,
2.63; Sn, 22.26. Found: C, 58.75; H, 6.11; N, 2.70; Sn,
22.08%. 1H NMR (CDCl3): 13.05 (4H, d, Ar–OH),
8.77(4H, d, N@CAH), 8.15(8H, d, H(a)), 7.40(8H, d,
H(b)), 6.94–7.38(16H, m, Ar–H), 1.16–1.90(88H, m,
CH3); 119Sn NMR (CDCl3): À226.5, À205.4; IR
(KBr): m(OH), 3421 cmÀ1
,
m(C@N), 1622 cmÀ1
,
,
2.3. Preparation of the complexes: general procedure
mas(COO), 1590, 1576, ms(COO), 1411, 1392 cmÀ1
m(Sn–O–Sn), 632 cmÀ1, m(Sn–C), 551 cmÀ1, m(Sn–O),
Complexes 1–4 were prepared using the same proce-
dure as described for complex 1. The reaction mixture
of di-n-butyltin oxide (0.248 g, 1.0 mmol) and LH2
(0.241 g, 1.0 mmol) were added to a solution of absolute
benzene (30 ml) and stirred under reflux for 7 h, cooled to
room temperature and evaporated under vacuum. The
solid was recrystallized from dichloromethane-hexane.
Complexes 5–10 were prepared using the same proce-
dure as described for complex 5. The solution of LH2
(0.241 g, 1.0 mmol) in benzene was added triphenyl-
tin(IV) chloride (0.385 g, 1.0 mmol) and Et3N (1.2
mmol). The mixture was refluxed for 1.5 h and the sol-
vent was removed by evaporation in vacuo. The crude
produces were recrystallized from dichloromethane–
hexane (see Scheme 2).
432 cmÀ1
.
2.3.3. {[Ph2Sn(LH)]2O}2 (3)
Orange crystals 0.432 g, yield 83%. M.p. 175–176 ꢁC.
Anal. Calc. for C104H80N4O14Sn4: C, 59.92; H, 3.87; N,
2.69; Sn, 22.78. Found: C, 59.75; H, 3.90; N, 2.78; Sn,
22.54%. 1H NMR (CDCl3): 13.11 (4H, d, Ar–OH),
8.75(4H, d, N@CAH), 8.08(8H, d, H(a)), 7.45(8H, d,
H(b)), 6.68–7.44(56H, m, Ar–H & Ph–H); 119Sn NMR
(CDCl3): À224.8, À205.0; IR (KBr): m(OH), 3424
cmÀ1, m(C@N), 1625 cmÀ1, mas(COO), 1604, 1578,
ms(COO), 1410, 1395 cmÀ1, m(Sn–O–Sn), 640 cmÀ1
,
m(Sn–C), 550 cmÀ1, m(Sn–O), 431 cmÀ1
.
2.3.4. {[Bz2Sn(LH)]2O}2 (4)
Orange crystals 0.499 g, yield 91%. M.p. 153–155 ꢁC.
Anal. Calc. for C112H96N4O14Sn4: C, 61.24; H, 4.40; N,
2.55; Sn, 21.61. Found: C, 61.02; H, 4.33; N, 2.62; Sn,
21.49%. 1H NMR (CDCl3): 13.05 (4H, d, Ar–OH),
8.70(4H, d, N@CAH), 8.14(8H, d, H(a)), 7.41(8H, d,
H(b)), 6.85–7.42(56H, m, Ar–H & Ph–H), 2.70–
2.75(16H, m, SnCH2); 119Sn NMR (CDCl3): À226.6,
À208.2; IR (KBr): m(OH), 3416 cmÀ1, m(C@N), 1622
cmÀ1, mas(COO), 1611, 1580, ms(COO), 1414, 1392
2.3.1. {[nBu2Sn(LH)]2O}2 (1)
Orange crystals 0.438 g, yield 91%. M.p. 147–149 ꢁC.
Anal. Calc. for C88H112N4O14Sn4: C, 54.92; H, 5.86; N,
2.91; Sn, 24.67. Found: C, 54.89; H, 5.89; N, 2.94; Sn,
OH
CH
Hb Ha
COOH
N
cmÀ1, m(Sn–O–Sn), 642 cmÀ1, m(Sn–C), 546 cmÀ1
m(Sn–O), 434 cmÀ1
,
Scheme 1.
.

H.D. Yin et al. / Journal of Organometallic Chemistry 690 (2005) 435–440
437
Table 1
Crystal date and details of structure refinement for {[nBu2Sn(LH)]2O}2
(1) and Ph3Sn(LH) (5)
2.3.5. Ph3Sn(LH) (5)
Orange crystals 0.513, yield 87%. M.p. 125–127 ꢁC.
Anal. Calc. for C32H25NO3Sn: C, 65.12; H, 4.27; N,
2.37; Sn, 20.11. Found: C, 65.09; H, 4.28; N, 2.35; Sn,
20.09%. 1H NMR (CDCl3): 13.01 (1H, s, Ar–OH),
8.62(1H, s, N@CAH), 8.20(2H, d, H(a)), 7.81(6H, t,
SnPh–H,), 7.51(2H, d, H(b)), 6.94–7.47(13H, m, Ar–H
& SnPh–H);119Sn NMR (CDCl3): À204.7; IR (KBr):
m(OH), 3428 cmÀ1, m(C@N), 1620 cmÀ1, mas(COO),
Complex
1
5
Empirical formula
Formula weight
Crystal size (mm)
Crystal system
C88H112N4O14Sn4
1924.58
C32H 25NO3Sn
590.22
0.39 · 0.34 · 0.27
Triclinic
0.42 · 0.35 · 0.09
Monoclinic
P21/c
ꢀ
Space group
Unit cell dimensions
P1
1598 cmÀ1, ms(COO), 1408 cmÀ1; m(Sn–C), 563 cmÀ1
m(Sn–O), 442 cmÀ1
,
˚
a (A)
12.352(9)
12.875(10)
15.267(11)
102.559(11)
1.358
6.8950(14)
46.350(3)
8.7250(17)
95.472(3)
1.412
˚
b (A)
.
˚
c (A)
b (ꢁ)
Dcalc density (mg/m3)
F(000)
2.3.6. Cy3Sn(LH) (6)
Orange crystals 0.441 g, yield 73%. M.p. 117–119 ꢁC.
Anal. Calc. for C32H40NO3Sn: C, 63.49; H, 6.66; N,
2.31; Sn, 19.61. Found: C, 63.47; H, 6.69; N, 2.35; Sn,
19.59%. 1H NMR (CDCl3): 13.08 (1H, s, Ar–OH),
8.62(1H, s, N@CAH), 8.12(2H, d, H(a)), 7.43(2H, d,
H(b)), 6.93–7.30(4H, m, Ar–H), 1.35–1.97(30H, m,
SnCy–H);119Sn NMR (CDCl3): À207.2; IR (KBr):
m(OH), 3393 cmÀ1, m(C@N), 1624 cmÀ1, mas(COO),
980
1192
Scan range h (ꢁ)
Total/unique/Rint
Goodness-of-fit on F2
R1/wR2
1.59–25.02
11959/8128/0.0238
0.963
1.76–25.03
10364/3922/0.1001
1.017
0.0471/0.1085
1.107
0.0748/0.1602
0.953
l (mmÀ1
max/qmin (e A
)
À3
˚
q
)
0.897/À0.480
0.699/À1.335
(CDCl3): À207.7; IR (KBr): m(OH), 3408 cmÀ1
,
m(C@N), 1614 cmÀ1, mas(COO), 1598 cmÀ1, ms(COO),
1595 cmÀ1, ms(COO), 1414 cmÀ1; m(Sn–C), 533 cmÀ1
m(Sn–O), 430 cmÀ1
,
1411 cmÀ1; m(Sn–C), 562 cmÀ1, m(Sn–O), 460 cmÀ1
.
.
2.3.10. (4-Cl-PhCH2)3Sn(LH) (10)
2.3.7. Bz3Sn(LH) (7)
Orange crystals 0.617 g, yield 84%. M.p. 124–126 ꢁC.
Anal. Calc. for C35H28Cl3NO3Sn: C, 57.14; H, 3.84; N,
1.90; Sn, 16.14. Found: C, 57.15; H, 3.83; N, 1.93; Sn,
16.12%. 1H NMR (CDCl3): 12.92 (1H, s, Ar–OH),
8.66(1H, s, N@CAH), 8.06(2H, d, H(a)), 7.44(2H, d,
H(b)), 6.77–7.42(16H, m, Ar–H & Ph–H), 2.70(6H, t,
SnCH2, JSn–H = 67.61);119Sn NMR (CDCl3): À208.2;
Orange crystals 0.480 g, yield 76%. M.p. 123–125 ꢁC.
Anal. Calc. for C35H31NO3Sn: C, 66.48; H, 4.94; N,
2.22; Sn, 18.77. Found: C, 66.46; H, 4.91; N, 2.25; Sn,
18.76%. 1H NMR (CDCl3): 13.03 (1H, s, Ar–OH),
8.66(1H, s, N@CAH), 8.08(2H, d, H(a)), 7.42(2H, d,
H(b)), 6.81–7.38(19H, m, Ar–H & Ph–H), 2.69(6H, t,
SnCH2, JSn–H = 69.63);119Sn NMR (CDCl3): À210.3;
IR (KBr): m(OH), 3420 cmÀ1, m(C@N), 1620 cmÀ1
,
IR (KBr): m(OH), 3387 cmÀ1, m(C@N), 1608 cmÀ1
,
mas(COO), 1601 cmÀ1, ms(COO), 1418 cmÀ1; m(Sn–O),
mas(COO), 1596 cmÀ1, ms(COO), 1402 cmÀ1; m(Sn–C),
528 cmÀ1, m(Sn–O), 455 cmÀ1
557 cmÀ1, m(Sn–C), 451 cmÀ1
.
.
2.4. X-ray crystallography
2.3.8. (2-Cl-PhCH2)3Sn(LH) (8)
Orange crystals 0.632 g, yield 86%. M.p. 119–121 ꢁC.
Anal. Calc. for C35H28Cl3NO3Sn: C, 57.14; H, 3.84; N,
1.90; Sn, 16.14. Found: C, 57.12; H, 3.86; N, 1.91; Sn,
16.11%. 1H NMR (CDCl3): 13.03 (1H, s, Ar–OH),
8.66(1H, s, N@CAH), 8.05(2H, d, H(a)), 7.45(2H, d,
H(b)), 6.75–7.41(16H, m, Ar–H & Ph–H), 2.79(6H, t,
SnCH2, J Sn–H = 68.75); 119Sn NMR (CDCl3): À205.8;
X-ray crystallographic data for the complexes 1 and 5
were collected on a Bruker smart-1000 CCD diffractom-
˚
eter at 293(2) K using Mo Ka radiations (0.71073 A).
The structures were solved by direct method and differ-
ence Fourier map using SHELXL-97 program, and
refined by full-matrix least-squares on F2. All non-hy-
drogen atoms were refined anisotropically. Hydrogen
atoms were located at calculated positions and refined
isotropically. Further details are given in Table 1.
IR (KBr): m(OH), 3431 cmÀ1, m(C@N), 1618 cmÀ1
,
mas(COO), 1597 cmÀ1, ms(COO), 1398 cmÀ1; m(Sn–C),
563 cmÀ1, m(Sn–O), 458 cmÀ1
.
2.3.9. (4-F-PhCH2)3Sn(LH) (9)
3. Results and discussion
Orange crystals 0.528 g, yield 77%. M.p. 127–129
ꢁC. Anal. Calc. for C35H28F3NO3Sn: C, 61.25; H,
4.11; N, 2.04; Sn, 17.30. Found: C, 61.24; H, 4.13;
N, 2.06; Sn, 17.27%. 1H NMR (CDCl3): 12.98 (1H,
s, Ar–OH), 8.66(1H, s, N@CAH), 8.06(2H, d, H(a)),
7.43(2H, d, H(b)), 6.61–7.36(16H, m, Ar–H & Ph–
H), 2.69(6H, t, SnCH2, JSn–H = 71.45);119Sn NMR
3.1. Crystal structures
The ORTEP drawings of complexes 1 and 5 are
shown in Figs. 1 and 2. The selected bond lengths and
angles are listed in Tables 2 and 3.

438
H.D. Yin et al. / Journal of Organometallic Chemistry 690 (2005) 435–440
Fig. 1. ORTEP drawing of complex 1.
Fig. 2. ORTEP drawing of complex 5.
Complex {[nBu2Sn(LH)]2O}2 (1), possesses teranu-
clear centrosymmetric dimeric structure with a four-
membered planar Sn2O2 ring with the Sn–O bond
2.253(4), 2.863(5), 2.200(4), 2.674(4) A, respectively,
which are close to that found in the literature [17]. The
exo-cyclic tin atom Sn(1) forms five primary bonds:
one to the O(7) atom, two to the carboxylate oxygen
atoms O(1) and O(4), and two to the tin-bound n-butyl
groups. In addition the Sn(1) atom makes a close con-
˚
˚
˚
distances 2.040(4) A for Sn(2)–O(7), 2.151(3) A for
˚
Sn(2)–O(7A) and 2.020(4) A for Sn(1)–O(7), which are
similar to the corresponding distances of the complex
{[nBu2Sn(2-MeOC6H4COO)]2O}2 [17]. In the molecule,
the four carboxylate ligands are divided into two differ-
ent types according to their coordinating fashion. Two
of them are bidentate and connect with each of of exo-
and endo-cyclic tin atoms by using both oxygen atoms,
whereas the other two are tridentate with one oxygen
atom bridging to both of the exo- and endo-cyclic tin
atoms and the other oxygen atom to the exo-cyclic tin
atom. The bond distances of Sn(1)–O(1), Sn(2)–O(2),
Sn(1)–O(5), Sn(1)–O(4) and Sn(2)–O(4A) are 2.263(4),
˚
tact of 2.863 A with the O(5) atom. The contact is signif-
˚
icantly less than 3.68 A, the sum of the van der Waals
radii for Sn and O atoms [18,19]. The Sn(1) atom is
therefore best be described as six-coordinated in a
monocapped trigonal bipyramid geometry with the
O(7), C(29) and C(33) atoms occupying the equatorial
positions, and the O(1) and O(4) atoms taking up the
axial positions. The endo-cyclic tin atom Sn(2) is six-
coordinated in a distorted octahedral geometry, with
the atoms C(37), C(41), O(4A) and O(7) occupying

H.D. Yin et al. / Journal of Organometallic Chemistry 690 (2005) 435–440
439
Table 2
Selected bond distances (A) and angles (ꢁ) of {[ Bu2Sn(LH)]2O}2 (1)
C(21)–Sn–C(27) 121.3(4)ꢁ, C(21)–Sn–C(15) 111.9(3)ꢁ,
C(27)–Sn–C(15) 105.5(4)ꢁ is 338.7ꢁ, which indicates that
the Sn, C(15), C(21) and C(27) atoms are almost in the
same plane. Studies show that the phenolate oxygen and
the imino nitrogen atoms are also in nonparticipation in
coordination to the tin atoms, which is similar to that of
the complex 1. In the molecular structure of the title
complex, the O(3) forms two hydrogen bonds with the
intramolecular N(1) and the intermolecular O(3i) (i:
Àx À 1, Ày, Àz) atoms. The hydrogen bond distances
of O(3)–H(3A)Á Á ÁN(1) and O(3)–H(3A)Á Á ÁO(3i) are
2.678 and 3.147, and the hydrogen bond angles of
O(3)–H(3A)Á Á ÁN(1) and O(3)–H(3A)Á Á ÁO(3i) are
131.21ꢁ and 125.47ꢁ.
n
˚
Sn(1)–O(7)
2.020(4) Sn(2)–O(7)
2.098(8) Sn(2)–C(37)
2.100(9) Sn(2)–C(41)
2.200(4) Sn(2)–O(7A)
2.263(4) Sn(2)–O(2)
2.863(5) Sn(2)–O(4A)
2.040(4)
2.083(9)
2.098(7)
2.151(3)
2.253(4)
2.674(4)
Sn(1)–C(33)
Sn(1)–C(29)
Sn(1)–O(4)
Sn(1)–O(1)
Sn(1)–O(5)
O(7)–Sn(1)–C(33)
O(7)–Sn(1)–C(29)
C(33)–Sn(1)–C(29) 137.2(3)
110.5(2)
112.1(3)
O(7)–Sn(2)–C(37)
O(7)–Sn(2)–C(41)
C(37)–Sn(2)–C(41)
109.9(3)
105.2(2)
143.3(3)
76.61(15)
97.4(3)
O(7)–Sn(1)–O(4)
C(33)–Sn(1)–O(4)
C(29)–Sn(1)–O(4)
O(7)–Sn(1)–O(1)
C(33)–Sn(1)–O(1)
C(29)–Sn(1)–O(1)
O(4)–Sn(1)–O(1)
O(7)–Sn(1)–O(5)
C(33)–Sn(1)–O(5)
C(29)–Sn(1)–O(5)
O(4)–Sn(1)–O(5)
O(1)–Sn(1)–O(5)
78.25(14) O(7)–Sn(2)–O(7A)
94.7(2)
97.6(3)
91.13(14) O(7)–Sn(2)–O(2)
C(37)–Sn(2)–O(7A)
C(41)–Sn(2)–O(7A)
100.9(2)
89.99(15)
85.4(3)
89.1(2)
86.2(3)
C(37)–Sn(2)–O(2)
C(41)–Sn(2)–O(2)
84.2(2)
169.38(15) O(7A)–Sn(2)–O(2)
127.18(13) O(7)–Sn(2)–O(4A)
166.48(15)
142.69(12)
76.9(3)
3.2. Infrared spectra
79.2(2)
78.6(3)
C(37)–Sn(2)–O(4A)
C(41)–Sn(2)–O(4A)
81.8(2)
66.09(12)
127.31(13)
The infrared spectra of all the organotin(IV) com-
plexes have been recorded and some important assign-
ments are shown above. The infrared spectra of all the
ten complexes show strong typical broad bands at
3387–3431 cmÀ1 related to the phenolic hydrogen
stretching vibration according to the previous report
[21], which strongly indicates that in the complexes the
phenolic oxygen atoms do not participate in coordina-
tion to the tin atoms. The bands appearing at 1608–
1624 cmÀ1 for all the complexes can be assigned as
m(C@N) vibration according to the previous reports
[22–24] show that the amino nitrogen atoms are not par-
ticipating in coordination to the tin atom.
The Dm(mas(CO2) À ms(CO2)) value is used to deter-
mine the nature of bonding of carboxylate to tin(IV)
complexes [25]. It is generally believed that the difference
in Dm between asymmetric (mas(CO2)) and symmetric
(ms(CO2)) absorption frequencies below 200 cmÀ1 for
the bidentate carboxylate moiety, but greater than 200
cmÀ1 for the unidentate carboxylate moiety. All the val-
ues of Dm of the ten complexes are between 154 and 199
cmÀ1, and this indicate that all the seven title complexes
adopt bidentate carboxylate structure. For complexes 1–
4, The peak appearing at 632–642 cmÀ1 can be assigned
to the m (Sn–O–Sn) mode [26–28].
48.94(13) O(7A)–Sn(2)–O(4A)
141.67(14) O(2)–Sn(2)–O(4A)
Symmetry equivalent positions: A, 2 À x, 1 À y, Àz.
Table 3
Selected bond distances (A) and angles (ꢁ) of Ph3Sn(LH) (5)
˚
Sn–O(1)
Sn–C(21)
2.078(6)
2.116(9)
2.145(8)
2.156(8)
2.732(6)
N(1)–C(8)
N(1)–C(5)
1.297(11)
1.408(11)
1.324(9)
1.221(10)
1.335(10)
85.1(3)
Sn–C(27)
Sn–C(15)
Sn–O(2)
O(1)–C(1)
O(2)–C(1)
O(3)–C(10)
O(1)–Sn–C(21)
O(1)–Sn–C(27)
C(21)–Sn–C(27)
O(1)–Sn–C(15)
C(21)–Sn–C(15)
C(27)–Sn–C(15)
O(1)–Sn–O(2)
108.3(3)
C(21)–Sn–O(2)
C(27)–Sn–O(2)
C(15)–Sn–O(2)
C(8)–N(1)–C(15)
C(1)–O(1)–Sn
C(1)–O(2)–Sn
O(2)–C(1)–O(1)
110.0(3)
121.3(4)
97.1(3)
84.1(3)
149.9(3)
122.2(7)
106.4(5)
78.5(5)
111.9(3)
105.5(4)
53.06(19)
122.0(8)
equatorial positions as indicated by the sum of the bond
angles (373.8ꢁ) around the tin formed by these atoms.
The axial positions are occupied by O(2) and the
O(7A) atoms, and the bond angle, O(2)–Sn(2)–O(7A),
of 166.48(15)ꢁ deviates significantly from linearity.
There is no evidence showing that the phenolate oxygen
and the imino nitrogen atom have any bonding interac-
tion to the tin atom.
1
3.3. H NMR spectra
Complex Ph3Sn(LH) (5) is a monomer as shown in
Fig. 2. The molecule of the title complex conforms to
the chelated monomeric structure with the central tin
atom five-coordinated to three tin-bounded phenyl
groups and the chelated carboxylate group. As is fre-
quently the case, the carboxylate is unsymmetrically
bidentate, the long Sn–O contact comprising significant
perturbations on a basically four-coordinate array
about the central tin atom. The Sn–O bond lengthes
The Ar–OH resonance appeared in the region 1.92–
13.11 ppm as singlet for all the complexes strongly sug-
gest that the phenolic oxygen atoms do not participate
in coordination to the tin atoms for all the ten title com-
plexes, and this is quite different from that of the four
complexes we have reported [14]. The chemical shift of
the protons of azomethine (HC@N) proton resonances
exhibit signals in the region 8.62–8.77 ppm for all the
ten complexes, the figures are similar to the uncoordi-
nated ligand [15], and this show that the azomethine
nitrogen atoms do not participate in coordinating to
˚
˚
2.078(6) A for Sn–O(1) and 2.732(6) A for Sn–O(2)
are similar to those of the Ph3(4-C2H5OC6H4COO)
˚
(2.050(4), 2.837(4) A) [20]. The sum of the bond angles

440
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Acknowledgement
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We acknowledge the Financial support of the Shandong
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