Synthesis and structural characterization of diorganotin(IV) esters of salicylidene-amino acids

Article abstract of DOI:10.1016/j.jorganchem.2004.05.004

Eight diorganotin esters of salicylidene-L-tryptophan(Sal-T) and salicylidene-L-valine(Sal-V), [(n-Bu)₂Sn(Sal-T)] (1), [(n-Bu)₂ Sn(Sal-V)] (2), [Ph₂Sn(Sal-T)] (3), [Ph ₂Sn(Sal-V)] (4), [(PhCH₂)_2<

Full text of DOI:10.1016/j.jorganchem.2004.05.004

Journal of Organometallic Chemistry 689 (2004) 2480–2485
www.elsevier.com/locate/jorganchem
Synthesis and structural characterization of diorganotin(IV) esters of
salicylidene-amino acids
*
Han-Dong Yin , Qi-Bao Wang, Sheng-Cai Xue
Department of Chemistry, Liaocheng University, Liaocheng 252059, China
Received 3 April 2004; accepted 3 May 2004
Abstract
Eight diorganotin esters of salicylidene-L-tryptophan(Sal-T) and salicylidene-L-valine(Sal-V), [(n-Bu)2Sn(Sal-T)] (1), [(n-Bu)2Sn-
(Sal-V)] (2), [Ph2Sn(Sal-T)] (3), [Ph2Sn(Sal-V)] (4), [(PhCH2)2Sn(Sal-T)] (5), [(PhCH2)2Sn(Sal-V)] (6), [(4-ClC6H4CH2)2Sn(Sal-T)] (7)
1
and [(4-ClC6H4CH2)2Sn(Sal-V)] (8) have been synthesized and characterized by elemental analysis, IR and H NMR. The crystal
structures of compounds 1 and 2 have been determined by X-ray single crystal diffraction. Their structures show the tin atoms
of two compounds are rendered five-coordinated in distorted trigonal bipyramidal geometries.
ꢀ 2004 Published by Elsevier B.V.
Keywords: Salicylidene-amino acid; Diorganotin; Crystal structure
1. Introduction
shown in Scheme 1. The tin atoms are five-coordinated
by the two n-butyl carbon atoms and two oxygen atoms
one from carboxylate and one from the phenolic hydro-
gen and the imino nitrogen atom.
Recently, organotin(IV) compounds with schiff bases
have received increased attention owing to their anti-tu-
mour activities [1–9], in particular the organotin(IV) es-
ters of N-arylidene-amino acids have been observed to
exhibit a great anti-tumour activity against human tu-
mour cell lines [10]. As an extension of studies of or-
ganotin(IV) compounds with schiff bases, we
synthesized eight new diorganotin esters of salicylid-
ene-amino acids by the reaction of diorganotin oxide
and salicylidene-amino acids in 1:1 stoichiometry. The
details of the synthesis, structure and spectra character-
izations of the compounds 1–8 are reported herein. Two
of the compounds have been studied by X-ray diffrac-
tion, and show that both compound 1 and 2 are mono-
mer and adopt the same structure to the literature [11] as
2. Experimental
2.1. Materials and methods
Dibutyltin oxide and diphenyltin oxide were commer-
cially available and used without further purification.
The melting points were obtained with Kolfer micro
melting point apparatus and were uncorrected. IR spec-
tra were recorded on a Nicolet-460 spectrophotometer
1
using KBr discs and sodium chloride optics. H, 13C
and 119Sn NMR spectra were obtained with Mercury
Plus-400 NMR spectrometer and the chemical shifts
are given in ppm relative to Me4Si, Me4Sn in CDCl3.
Elemental analyses were performed in a PE-2400 II ele-
mental analyzer.
*
Corresponding author. Tel./fax: +86-635-823-8121/9121.
E-mail addresses: handongyin@lctu.edu.cn, handongyin@sohu.
com (H.-D. Yin).
0022-328X/$ - see front matter ꢀ 2004 Published by Elsevier B.V.
doi:10.1016/j.jorganchem.2004.05.004

H.-D. Yin et al. / Journal of Organometallic Chemistry 689 (2004) 2480–2485
2481
d
173.85(CH‚N), 172.03(COO), 68.61(‚NCH),
R
O
32.40(CH2Ar), 169.21, 137.42, 136.48, 126.62, 124.32,
122.85, 120.33, 118.85, 116.83, 111.51(Ar–C), 27.08,
26.87, 26.71, 26.50, 21.87, 21.62, 13.61, 13.48-
(Sn(CH2CH2CH2CH3)2). 119Sn NMR d À305.55. IR
(KBr, cmÀ1): 3437(N–H), 1653, 1350(CO2), 1614-
(C‚N), 602, 541(Sn–O), 450(Sn–C), 428(Sn–N).
R
C
O
Sn
N
O
R'
CH
[(n-Bu)2Sn(Sal-V)] (2): Yield: 91%, m.p. 156–158 ꢁC.
Anal. Found: C, 53.25; H, 6.98; N, 3.37; Sn, 26.04%.
Calc. for C20H31NO3Sn: C, 53.13; H, 6.91; N, 3.10;
1
Sn, 26.25. H NMR (CDCl3): d 8.24(1H, s, CH‚N),
Scheme 1.
6.75–7.46(4H, m, aromatic-H), 3.84(1H, d, J=6.8 Hz,
NCHCO), 2.33(1H, m, CHMe2), 122–1.79(12H, m,
Sn–(CH2)3–), 1.09(3H, d, J=6.8 Hz, CH3), 1.06(3H, d,
J=6.8 Hz, CH3), 0.96(3H, t, J=7.2 Hz, CH3), 0.80
(3H, t, J=7.2 Hz, CH3). 13C NMR (CDCl3): d
173.14(CH‚N), 172.37(COO), 74.64(‚NCH), 169.63,
137.71, 135.47, 122.74, 117.38(Ar–C), 34.52, 19.08,
18.37(Pr-i), 26.97, 26.87, 26.95, 26.65, 22.55, 20.91,
13.58, 13.48 (Sn(CH2CH2CH2CH3)2). 119Sn NMR
dÀ302.32. IR (KBr, cmÀ1): 1670, 1334(CO2),
1608(C‚N), 585, 541(Sn–O), 459(Sn–C), 414(Sn–N).
[Ph2Sn(Sal-T)] (3): Yield: 86%, m.p. 216–218 ꢁC.
Anal. Found: C, 62.38; H, 4.25; N, 4.83; Sn, 20.33%.
Calc. for C30H24N2O3Sn: C, 62.21; H, 4.18; N, 4.84;
2.2. Preparation of schiff base
The schiff bases, Sal-T (1) and Sal-V (2) have been
prepared by the refluxing of salicylidene with -trypto-
phan and -valine, respectively, in ethanol in 1:1 mole
L
L
ratio for 5 h. The crude schiff bases were obtained after
evaporation of solvent, washed with petroleum ether
(40–60 ꢁC) and was finally recrystallized from methanol
before use. The molecular structures, melting points, ab-
breviation and yield of the two schiff bases are shown as
follows (Table 1).
1
Sn, 20.49. H NMR (CDCl3): d 8.04(1H, s, CH‚N),
2.3. Synthesis of diorganotin compounds
7.94(1H, s, N–H), 6.52–7.82(19H, m, aromatic-H),
4.27(1H, d, J=11.0 Hz, CHAr), 3.70(1H, d, J=11.0
Hz, CHAr), 2.83(1H, q, J=10.2 Hz, NCHCO). 13C
To a benzene suspension of dialkyltin oxide (2.0
mmol) was added a benzene solution of Sal-T or Sal-V
(2.0 mmol). The mixture was heated under reflux with
strring for 6–7 h, and the clear solution thus obtained
was evaporated under vacuum to leave a yellow solid,
which was recrystallized from dichloromethane-hexane
to give yellow crystals.
NMR (CDCl3):
d 173.67(CH‚N), 171.74(COO),
68.76(‚NCH), 31.99(CH2Ar), 169.10, 138.01, 137.75,
136.61, 136.34, 135.34, 130.80, 129.05, 126.46, 124.68,
122.73 122.64, 120.25, 118.65, 117.54, 116.89, 111.54,
109.06(Ar–C). 119Sn NMR d À352.37. IR (KBr,
cmÀ1): 3430(N–H), 1650, 1339(CO2), 1609(C‚N), 586,
541(Sn–O), 446(Sn–C), 421(Sn–N).
[Ph2Sn(Sal-V)] (4): Yield: 87%, m.p. 191–193 ꢁC.
Anal. Found: C, 58.47; H, 4.75; N, 2.87; Sn, 24.21%.
Calc. for C24H23NO3Sn: C, 58.57; H, 4.71; N, 2.85;
Sn, 24.12. 1H NMR (CDCl3): 8.26(1H, s, CH‚N),
6.80–8.04(19H, m, aromatic-H), 3.95(1H, d, J=4.8 Hz,
NCHCO), 2.30(1H, m, CHMe2), 0.97(3H, d, J=6.8
Hz, CH3), 0.87(3H, d, J=6.8 Hz, CH3). 13C NMR
[(n-Bu)2Sn(Sal-T)] (1): Yield: 84%, m.p. 166–168 ꢁC.
Anal. Found: C, 57.83; H, 5.90; N, 5.23; Sn, 22.19%.
Calc. for C26H32N2O3Sn: C, 57.91; H, 5.98; N, 5.19;
1
Sn, 22.01. H NMR (CDCl3): d 8.10(1H, s, CH‚N),
7.81(1H, s, N–H), 6.58–7.39(9H, m, aromatic-H),
4.24(1H, d, J=8.2 Hz, CHAr), 3.80(1H, dt, J=8.2 Hz,
CHAr), 3.06(1H, dt, J=8.4 Hz, NCHCO), 1.21–
1.70(12H, m, Sn–(CH2)3–), 0.79(3H, t, J=7.2 Hz,
CH3), 0.94(3H, t, J=7.2 Hz, CH3). 13C NMR (CDCl3):
Table 1
Structures, abbreviations and melting points of the schiff bases
Structure
Abbreviation
Sal-T
Yield (%)
91
Melting point
decomposed (=200 ꢁC)
OH
COOH
CH -
2 CH
N
CH
OH
N
H
Sal-V
92.5
182–183 ꢁC
COOH
CH3
N
CH
CH CH
CH3

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H.-D. Yin et al. / Journal of Organometallic Chemistry 689 (2004) 2480–2485
Table 2
Crystallographic data of compounds 1 and 2
(CDCl3):
d
172.95(CH‚N),
172.71(COO),
74.34(‚NCH), 169.68, 138.20, 137.65, 136.60, 135.79,
130.82, 130.67, 128.93, 123.05, 117.26(Ar–C), 34.87,
19.03, 18.49(Pr-i). 119Sn NMR d À348.53. IR (KBr,
cmÀ1): 1671, 1331(CO2), 1613(C‚N), 586, 541(Sn–O),
446(Sn–C), 419(Sn–N).
Compound
1
2
Empirical formula
Formula weight
Temperature (K)
C26H32N2O3Sn
539.23
298(2)
C20H31NO3Sn
452.15
298(2)
˚
Wavelength (A)
0.71073
Triclinic
0.71073
Orthorhombic
P2(1)2(1)2(1)
[(PhCH2)2Sn(Sal-T)] (5): Yield: 73%, m.p. 202–204
ꢁC. Anal. Found: C, 63.50; H, 4.72; N, 4.77; Sn,
19.47%. Calc. for C32H28N2O3Sn: C, 63.29; H, 4.65;
N, 4.61; Sn, 19.54. 1H NMR (CDCl3): 8.18(1H, s,
CH‚N), 7.97(1H, s, N–H), 6.85–7.84(19H, m, aromat-
ic-H), 4.25(1H, d, J=9.4 Hz, CHAr), 3.77(1H, d, J=9.4
Hz, CHAr), 3.11(1H, q, J=10.0 Hz, NCHCO), 3.01(4H,
Crystal system
Space group
Unit cell dimensions
ꢀ
P1
˚
a (A)
10.299(4)
11.332(4)
12.444(4)
101.812(5)
1236(8)
2
9.199(19)
10.01(2)
23.45(5)
90
˚
b (A)
˚
c (A)
b (ꢁ)
Volume (A )
3
˚
2155(8)
4
1.394
t, J=78.5 Hz, CH2Sn). 13C NMR (CDCl3):
d
Z
173.91(CH‚N), 172.06(COO), 68.59(‚NCH), 32.04-
(CH2Ar), 30.87(CH2Sn), 169.35, 138.27, 137.70,
136.81, 136.47, 135.50, 131.02, 130.10, 128.72, 126.52,
124.23, 122.58, 122.47, 118.74, 117.65, 116.72, 115.73,
109.57(Ar–C). 119Sn NMR d À348.05. IR (KBr,
cmÀ1): 3425(N–H), 1653, 1333(CO2), 1605(C‚N), 582,
547 (Sn–O), 448(Sn–C), 424(Sn–N).
[(PhCH2)2Sn(Sal-V)] (6): Yield: 77%, m.p. 178–179
ꢁC. Anal. Found: C, 60.25; H, 5.18; N, 2.73; Sn,
22.69%. Calc. for C26H27NO3Sn: C, 60.03; H, 5.23; N,
2.69; Sn, 22.82. 1H NMR (CDCl3): 8.18(1H, s, CH‚N),
N), 7.03–7.92(14H, m, aromatic-H), 3.97(1H, d, J=5.0
Hz, NCHCO), 2.99(4H, t, J=80.2 Hz, CH2Sn),
2.36(1H, m, CHMe2), 0.96(3H, d, J=6.6 Hz, CH3),
0.86(3H, d, J=6.6 Hz, CH3). 13C NMR (CDCl3): d
Calculated density
(Mg/m3)
F(000)
1.449
552
928
Crystal size (mm)
Scan range h (ꢁ)
Limiting indices
0.38·0.32·0.26
1.76–25.03
À126h610;
À136k612;
À146l614
6530/4312/0.0211
0.989
0.42·0.25·0.19
1.74–25.02
À106h69;
À116k611;
À266l627
10885/3737/0.0382
0.959
Total/unique/Rint
Goodness-of-fit on F2
R1/wR2
0.0373/0.0847
1.062
0.0380/0.0806
1.202
l (mmÀ1
max/qmin (e A
)
À3
˚
q
)
0.601/À0.592
0.981/À0.614
CH2Sn), 2.34(1H, m, CHMe2), 0.94(3H, d, J=6.4 Hz,
CH3), 0.85(3H, d, J=6.4 Hz, CH3). 13C NMR (CDCl3):
173.46(CH‚N),
172.88(COO),
74.85(‚NCH),
d
173.32(CH‚N), 172.24(COO), 74.57(‚NCH),
30.18(CH2Sn), 169.65, 137.80, 135.62, 135.32, 134.23,
130.28, 129.15, 123.01, 117.42, 117.38(Ar–C), 34.92,
19.52, 18.63(Pr-i). 119Sn NMR d À334.03. IR (KBr,
cmÀ1): 1663, 1341(CO2), 1610(C‚N), 581, 547(Sn–O),
457(Sn–C), 417(Sn–N).
30.24(CH2Sn), 169.72, 168.89, 146.42, 135.98, 135.64,
130.02, 122.69, 120.11, 117.51, 117.42(Ar–C), 34.72,
19.21, 18.63(Pr-i). 119Sn NMR d À321.75. IR (KBr,
cmÀ1): 1661, 1330(CO2), 1613(C‚N), 590, 551(Sn–O),
457(Sn–C), 423(Sn–N).
[(4-ClC6H4CH2)2Sn(Sal-T)] (7): Yield: 73%, m.p.
233–235 ꢁC. Anal. Found: C, 556.98; H, 4.00; N, 4.09;
Sn, 17.61%. Calc. for C32H26N2O3Cl2Sn: C, 56.84; H,
2.4. X-ray crystallography
1
3.88; N, 4.14; Sn, 17.55. H NMR (CDCl3): 8.13(1H,
Crystallographic data and refinement details are given
in Table 2. All X-ray crystallographic data were collected
on a Bruker SMART CCD 1000 diffractometer. A crite-
rion of observability was used for the solution and refine-
ment. The structure was solved by direct method and
differential Fourier map using SHELXL-97 program, and
refined by full-matrix least-squares on F2. All non-hydro-
gen atoms were refined anisotropically. Position of hy-
drogen atoms were calculated and refined isotropically.
s, CH‚N), 7.94(1H, s, N–H), 6.55–7.90(17H, m, aro-
matic-H), 4.21(1H, d, J=11.4 Hz, CHAr), 3.82(1H, d,
J=11.4 Hz, CHAr), 3.16(1H, q, J=9.6 Hz, NCHCO),
2.98(4H, t, J=76.2 Hz, CH2Sn). 13C NMR (CDCl3): d
173.80(CH‚N),
172.11(COO),
68.64(‚NCH),
32.12(CH2Ar), 30.55(CH2Sn), 169.82, 168.43, 148.57,
137.63, 136.21, 134.30, 130.02, 126.49, 125.01, 124.37,
124.25, 123.02, 121.87, 120.47, 119.01, 117.13, 116.65,
111.30(Ar–C). 119Sn NMR d À337.65. IR (KBr,
cmÀ1): 3436(N–H), 1653, 1336(CO2), 1607(C‚N), 589,
546 (Sn–O), 441(Sn–C), 422(Sn–N).
3. Results and discussion
[(4-ClC6H4CH2)2Sn(Sal-V)] (8): Yield: 76%, m.p.
209–210 ꢁC. Anal. Found: C, 53.24; H, 4.30; N, 2.34;
Sn, 20.25%. Calc. for C26H25NO3Cl2Sn: C, 53.01; H,
4.28; N, 2.38; Sn, 20.15. H NMR (CDCl3): 8.20(1H,
s, CH‚N), 6.84–7.92(12H, m, aromatic-H), 3.92(1H,
d, J=5.0 Hz, NCHCO), 2.96(4H, t, J=77.8 Hz,
3.1. IR data
1
The assignment of IR bands of diorganotin(IV) com-
pounds 1–8 has been determined by comparison with

H.-D. Yin et al. / Journal of Organometallic Chemistry 689 (2004) 2480–2485
2483
the IR spectra of related organotin compounds, schiff
bases and dialkyltin oxides. A weak broad band in the
region 3250–2350 cmÀ1, which has been assigned to
the intramolecular hydrogen-bond OH in the Schiff ba-
ses [12], is not observed in the infrared spectra of the
eight title compounds. This indicates that the reactions
have taken place through the replacement of the pheno-
lic hydrogen in the compounds. This also confirms that
organotin(IV) compounds are indeed those of the de-
protonated forms of schiff base. The m(C‚N) band, oc-
curring between 1605 and 1614 cmÀ1, is considerably
shifted towards lower frequencies with respect to that
of the free schiff bases (1638–1622 cmÀ1), confirming
the coordination of the azomethine nitrogen to diorg-
anotin(IV) moiety. The stretching frequency is lowed
owing to the displacement of electron density from N
to Sn atom, this resulting in the weakening of the
C‚N bond as reported in the literature [13]. The
Dm(mas(CO2)Àms(CO2)) value is used to determine the na-
ture of bonding of carboxylate to tin(IV) atom [14]. It is
generally believed that the difference in Dm between
asymmetric (mas(CO2)) and symmetric ((ms(CO2)) absorp-
tion frequencies below 200 cmÀ1 for the bidentate car-
boxylate moiety, but greater than 200 cmÀ1 for the
unidentate carboxylate moiety. All the values of Dm of
The 119Sn chemical shift values in compounds (1–8)
are found to be in the range of À305.55 to À348.53
ppm. The appearance of chemical shift values in this re-
gion indicates five-coordination environment [11]
around the central tin atoms in these compounds.
3.3. X-ray studies
The crystal structure and unit cell of compound 1 are
shown in Fig. 1, and those of compound 2 in Figs. 2 and
3, respectively. All hydrogen atoms have been omitted for
the purpose of clarity. Tables 3 and 4, respectively, list se-
lected bond lengths and angles for compounds 1 and 2.
the eight compounds are between 303 and 340 cmÀ1
,
and strongly indicate that all the eight title compounds
adopt unidentate carboxylate structure.
1
3.2. H, 13C and 119Sn NMR spectra
The absence of the OH proton signal in the com-
pounds suggests the binding of a tin atom to the ligand
oxygen atoms through the replacement of phenolic pro-
tons (for 1–8) according to the literature [15]. The chem-
ical shift of the protons of azomethine (HC‚N) proton
resonances exhibit signals at 8.04–8.26 ppm as singlets
for compounds 1–8, they are similar to the literature
[16–18], and it strongly suggests that the azomethine ni-
trogen atom coordinates to tin atom for all of the eight
1
compounds. The H NMR spectra of compounds 5–8
show that the chemical shifts of the protons of methy-
lene on the benzyl group exhibit signals about 2.96–
3.01 ppm as a triplet which is caused by the tin (119Sn)
hydrogen coupling. And the spin–spin coupling constant
Jsn-H is equal 76.2–80.2 Hz. In addition, the presence of
the N–H proton signal (7.81–7.94 ppm) in the com-
pounds 1, 3, 5 and 7 supports that the indolyl group
N atom is in no coordination to Sn atom.
The comparison of 13C NMR spectra of the ligand
with the corresponding organotin compounds (1–8)
shows a downfield shifts in the position of CCH‚N and
CC–O signals and an upfield shifts in the position of
CCOO signal. These shifts indicate the tridentate behav-
iour of the carboxylate moieties in the compounds.
Fig. 1. Molecular structure and projection of compound 1.

2484
H.-D. Yin et al. / Journal of Organometallic Chemistry 689 (2004) 2480–2485
3.3.1. Structure of [(n-Bu)2Sn(Sal-T)] (1)
For compound 1, as shown in Fig. 1, the tin atom
forms four primary bonds: two to the n-butyl groups,
and two to oxygen atoms. In addition, there exists a
coordination interaction between tin and the imino ni-
˚
trogen atom. The Sn–N, 2.161(3) A bond of the com-
pound 1 is a little longer than that of the compound
{[Ph2Sn(2-OC10H6CH‚NCH2COO)]SnPh2Cl2} 2.136
˚
A [19], but shorter than that of [SnMe2(Salop)]
˚
2.221(3) A [16] and [Ph2Sn(2-OC6H4C(CH3)‚NCH2-
˚
COO)] 2.190(5) A [11], and it is considerably less than
the sum of the van der Waals radii of tin and nitrogen,
˚
˚
3.74 A [20]. The Sn(1)–O(1), 2.162(3) A bond of the
compound is longer than that of [Ph2Sn(2-
˚
OC6H4C(CH3)‚NCH2COO)], 2.127(4) A [11], but
shorter than that of [2-OHC10H6CH‚N(CH2)2COO-
Fig. 2. Molecular structure of compound 2.
˚
COOSnBu3], 2.383(5) A [21]. The Sn(1)–O(3), 2.093(3)
˚
A bond is longer than that of the compound [Ph2Sn(2-
˚
OC6H4C(CH3)‚NCH2COO)], 2.064 A but a little
shorter than that of the compound [Vin2Sn(2-
˚
OC6H4C(CH3)‚NCH2COO)OH2], 2.105 A [11].
The tin atom lies in the ligand plane and forms a five-
membered and a six-membered chelate ring with the li-
gand. Thus, two n-butyl groups and the imino nitrogen
take up the equatorial position, while the oxygen atoms,
O(1) and O(3), take up the axial sites around the Sn(1)
atom. The trigonal bipyramidal geometry of the central
tin atom is distorted as indicated by bonding angles of
158.75(11)ꢁ, 113.12(15)ꢁ, 122.4(12)ꢁ and 126.55(17)ꢁ for
O(3)–Sn(1)–O(1), C(23)–Sn(1)–N(1), C(19)–Sn(1)–N(1)
and C(19)–Sn(1)–C(23), respectively. The sum of the an-
gles O(1)–Sn(1)–N(1), 75.07(11)ꢁ, and O(3)–Sn(1)–N(1),
83.72(11)ꢁ is 158.79ꢁ, and it is the same with the angle
O(3)–Sn(1)–O(1), 158.75(11)ꢁ, so that the atoms Sn(1),
N(1), O(1) and O(3) are co-planer. The sum of the an-
gles C(23)–Sn(1)–N(1), C(19)–Sn(1)–N(1) and C(19)–
Sn(1)–C(23) is 362.07ꢁ, thus the atoms Sn(1), N(1),
C(19) and C(23) are almost in the same plane.
Fig. 3. Projection of compound 2.
Table 3
˚
Selected bond distances (A) and angles (ꢁ) for compound 1
Sn(1)–O(3)
2.093(3)
2.112(4)
2.127(4)
2.161(3)
2.162(3)
92.98(15)
95.50(16)
N(1)–C(12)
N(1)–C(2)
O(1)–C(1)
O(2)–C(1)
O(3)–C(14)
1.298(4)
1.479(4)
1.267(5)
1.218(4)
1.315(5)
Sn(1)–C(19)
Sn(1)–C(23)
Sn(1)–N(1)
Sn(1)–O(1)
O(3)–Sn(1)–C(19)
O(3)–Sn(1)–C(23)
C(23)–Sn(1)–N(1) 113.12(15)
O(3)–Sn(1)–O(1) 158.75(11)
3.3.2. Structure of [(n-Bu)2Sn(Sal-V)] (2)
The structure of compound 2 is similar to com-
pound 1 as shown in Fig. 2. The tin atom coordinates
to two n-butyl groups (Sn(1)–C(17) 2.104(7), Sn(1)–
C(19)–Sn(1)–C(23) 126.55(17) C(19)–Sn(1)–O(1) 96.50(14)
O(3)–Sn(1)–N(1) 83.72(11) C(23)–Sn(1)–O(1) 94.04(15)
C(19)–Sn(1)–N(1) 120.24(14) N(1)–Sn(1)–O(1)
75.07(11)
˚
C(13) 2.109(7) A) and to two oxygen atoms (Sn(1)–
˚
O(1) 2.152(5), Sn(1)–O(3) 2.108(5) A), and the imino
nitrogen atom also coordinates to the tin atom
˚
(Sn(1)–N(1) 2.146(6) A), thus providing an five-mem-
Table 4
Selected bond distances (A) and angles (ꢁ) for compound 2
˚
Sn(1)–C(17)
Sn(1)–O(3)
2.104(7)
2.108(5)
2.109(7)
2.146(6)
2.152(5)
95.3(3)
N(1)–C(6)
N(1)–C(2)
O(1)–C(1)
O(2)–C(1)
O(3)–C(8)
1.300(7)
1.461(7)
1.288(8)
1.208(7)
1.301(7)
bered and an six-membered chelate ring. The sum of
the angles N(1)–Sn(1)–O(1), 74.28(19)ꢁ and O(3)–
Sn(1)–N(1), 81.62(19)ꢁ is 155.9ꢁ, and it is consistent
with the angle O(3)–Sn(1)–O(1), 155.07(18)ꢁ, so the at-
oms Sn(1), N(1), O(1) and O(2) are in the same plane.
Including the tin-nitrogen interaction the geometry at
tin becomes distorted trigonal bipyramidal with two
oxygen atoms in axial sites (O(3)–Sn(1)–O(1),
155.07(18)ꢁ) and one nitrogen and two n-butyl carbon
Sn(1)–C(13)
Sn(1)–N(1)
Sn(1)–O(1)
C(17)–Sn(1)-O(3)
C(13)–Sn(1)–N(1) 109.1(2)
C(17)–Sn(1)–O(1) 93.0(3)
C(17)–Sn(1)-C(13) 126.3(3)
O(3)–Sn(1)–C(13) 98.5(3)
C(17)–Sn(1)–N(1) 123.9(3)
O(3)–Sn(1)–O(1)
C(13)–Sn(1)–O(1) 95.4(3)
81.62(19) N(1)–Sn(1)–O(1) 74.28(19)
155.07(18)
O(3)–Sn(1)–N(1)

H.-D. Yin et al. / Journal of Organometallic Chemistry 689 (2004) 2480–2485
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2485
atoms occupying the equatorial plane (C(17)–Sn(1)–
C(13), 126.6(3)ꢁ; C(13)–Sn(1)–N(1), 109.1(2) and
C(17)–Sn(1)–N(13), 123.9(3)ꢁ). The sum of the angles
subtended at the tin atom in trigonal plane is 359.6ꢁ,
so that the atoms Sn(1), N(1), C(13) and C(17) are in
the same plane (see Fig. 3).
[3] V.I. Bregadze, S.A. Glazun, P.V. Petrovakii, Z.A. Starikova,
V.Y. Rochev, H. Dalil, M. Biesemans, R. Villem, M. Gielen,
D.D. Vos, Appl. Organomet. Chem. 17 (2003) 453.
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˚
The Sn–C bond lengths (2.104(7) and 2.109(7) A) of
the compound 2 is longer than those of compound 1
˚
(2.112(4) and 2.127(4) A). The Sn–N bond length
˚
(2.146(6) A) is quite close to compound 1 and other
compounds described in literature [11,19].
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4. Supplementary material
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metallics 17 (1998) 3058.
Crystallographic data for the structural analysis have
been deposited with the Cambridge Crystallographic
Data Center, CCDC No. 234625 for compound 1 and
CCDC No. 234626 for compound 2. Copies of this in-
formation may be obtained from The Director, CCDC,
12 Union Road, Cambridge CB2 1EZ, UK (fax: +44-
1233-336-033; e-mail: deposit@ccdc.cam.ac.uk).
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Rosair, S. Mitra, Polyhedron 18 (1999) 2687.
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Fun, Polyhedron 16 (1997) 2213.
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Acknowledgement
[17] C. Floriani, M. Puppis, F. Calderazzo, J. Organomet. Chem. 12
(1968) 209.
[18] R.J. Cozens, G.B. Deacon, P.W. Felder, K.S. Murray, B.O.
West, Aust. J. Chem. 23 (1970) 481.
We acknowledge the National Natural Foundation
PR China (20271025) and the Shandong Province Science
Foundation (L2003B01), and the State Key Laboratory
of Crystal Materials, Shandong University, PR China.
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