Organotin(IV) carboxylates based on benzenedicarboxylic acid derivatives: Syntheses, crystal structures and characterizations

Article abstract of DOI:10.1016/j.jorganchem.2012.05.038

Five organotin carboxylates based on 1,3-benzenedicarboxylic acid and 1,4-benzenedicarboxylic acid derivatives, namely (Ph₃Sn) ₂(4,6-L¹)(H₂O)₂·(C ₂H₅OH)·4H₂O (1) (4,6-L¹ = 4,6-bis(4-methyl-benzoyl)isophthalic acid), (Cy₃Sn) ₂(4,6-L¹)(DMF)₂ (2), (Ph₃Sn) ₂(4,6-L²)(DMF)₂ (3) (4,6-L² = 4,6-dibenzoylisophthalic acid), (Ph₃Sn)₂(2,5-L ³)(DMF)₂ (4) (2,5-L³ = 2,5-bis(4-isopropyl- benzoyl)terephthalic acid) and [(n-Bu₂Sn)₄(4,6-L ⁴)O₂(OH)(OC₂H₅)]₂· 2(C₂H₅OH) (5) (4,6-L⁴ = 4,6-bis(4-ethyl- benzoyl)isophthalic acid), have been synthesized. All the complexes have been characterized by elemental analysis, IR, ¹H and ¹³C NMR spectroscopy and X-ray crystallography diffraction analyses. The structural analysis reveals that complexes 1-3 show similar constructions, containing binuclear triorganotin skeletons based on 1,3-benzenedicarboxylic acid derivatives. Through intermolecular hydrogen bonds and C-H?π interactions, complex 1 demonstrates as a 3D architecture while 2 as a 1D chain and 3 as a 2D network. Complex 4 is a binuclear triorganotin based on 1,4-benzenedicarboxylic acid derivative. With the intermolecular C-H?π interaction, 4 shows a 2D network structure. Complex 5 has a ladder-like octanuclear architecture composed by two Sn₄O₄ ladders connected by two 1,3-benzenedicarboxylic acid derivatives and form an intramolecular 24-membered macrocycle.

Full text of DOI:10.1016/j.jorganchem.2012.05.038

Journal of Organometallic Chemistry 715 (2012) 54e63
Contents lists available at SciVerse ScienceDirect
Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
Organotin(IV) carboxylates based on benzenedicarboxylic acid derivatives:
Syntheses, crystal structures and characterizations
*
Xiao Xiao, Dafeng Du, Min Tian, Xiao Han, Jingwen Liang, Dongsheng Zhu , Lin Xu
Department of Chemistry, Northeast Normal University, 5268 Renmin Street, Changchun 130024, PR China
a r t i c l e i n f o
a b s t r a c t
Article history:
Five organotin carboxylates based on 1,3-benzenedicarboxylic acid and 1,4-benzenedicarboxylic acid
derivatives, namely (Ph3Sn)2(4,6-L1)(H2O)2$(C2H5OH)$4H2O (1) (4,6-L1 ¼ 4,6-bis(4-methyl-benzoyl)iso-
phthalic acid), (Cy3Sn)2(4,6-L1)(DMF)2 (2), (Ph3Sn)2(4,6-L2)(DMF)2 (3) (4,6-L2 ¼ 4,6-dibenzoylisophthalic
Received 20 April 2012
Received in revised form
22 May 2012
acid), (Ph3Sn)2(2,5-L3)(DMF)2 (4) (2,5-L3
¼
2,5-bis(4-isopropyl-benzoyl)terephthalic acid) and [(n-
Accepted 22 May 2012
Bu2Sn)4(4,6-L4)O2(OH)(OC2H5)]2$2(C2H5OH) (5) (4,6-L4 ¼ 4,6-bis(4-ethyl-benzoyl)isophthalic acid), have
been synthesized. All the complexes have been characterized by elemental analysis, IR, 1H and 13C NMR
spectroscopy and X-ray crystallography diffraction analyses. The structural analysis reveals that
complexes 1e3 show similar constructions, containing binuclear triorganotin skeletons based on 1,3-
Keywords:
Organotin carboxylate
1,3-Benzenedicarboxylic acid derivative
1,4-Benzenedicarboxylic acid derivative
Supramolecular structure
benzenedicarboxylic acid derivatives. Through intermolecular hydrogen bonds and CeH/
p interac-
tions, complex 1 demonstrates as a 3D architecture while 2 as a 1D chain and 3 as a 2D network. Complex
4 is a binuclear triorganotin based on 1,4-benzenedicarboxylic acid derivative. With the intermolecular C
eH/p interaction, 4 shows a 2D network structure. Complex 5 has a ladder-like octanuclear architecture
composed by two Sn4O4 ladders connected by two 1,3-benzenedicarboxylic acid derivatives and form an
intramolecular 24-membered macrocycle.
Ó 2012 Elsevier B.V. All rights reserved.
1. Introduction
carboxylates with esthetic architecture, we synthesized five new
organotin carboxylates herein.
Organotin(IV) carboxylates have received much attention,
owing to the enormous variety of intriguing structural topologies
and their unexpected properties for potential practical applications
[1e4]. The construction of multidimensional architectures depends
on the type of organic ligands, tineR groups, tin coordination
geometry preferences and metal-to-ligand molar ratio. In addition,
the intermolecular bond and interaction play key roles in the
generation of a variety of supramolecular structures such as
2. Experimental section
2.1. General and instrumental
The reagents were used as supplied while the solvents were
purified according to standard procedures [12]. The melting point
was obtained with Kofler micro-melting point apparatus and was
uncorrected. Elemental analyses (C, H, N) were carried out on
a PerkineElmer PE 2400 CHN instrument. 1H and 13C NMR spectra
were recorded on a Varian Mercury operating at 300 and 75 MHz,
respectively. IR spectra (KBr pellets) were recorded on an Alpha
Centauri FI/IR spectrometer (400e4000 cmꢀ1 range).
hydrogen bond and CeH/p interaction [5e8]. Polycarboxylic acid
is universally used as ligand to explore diversiform structures of
organotin carboxylate for its tendency to construct multinuclear
composition and the ability to form intra- and intermolecular
coordination and multidimensional architecture [9,10]. In the
previous paper, we have reported several novel organotin(IV)
complexes based on 1,3-benzenedicarboxylic acid and 1,4-
benzenedicarboxylic acid derivatives [11]. To further understand
the coordination chemistry and to explore novel organotin
2.2. X-ray crystallography
Diffraction intensities for complexes 1e5 were collected on
a Bruker CCD Area Detector image plate diffractometer by using the
ꢀ
u/
4
scan technique with Mo-K
a
radiation (
l
¼ 0.71073 A).
Absorption corrections were applied by using multiscan tech-
niques. The structure was solved by direct methods with SHELXS-
* Corresponding author. Tel.: þ86 13009010567; fax: þ86 0431 85684009.
E-mail address: zhuds206@nenu.edu.cn (D. Zhu).
0022-328X/$ e see front matter Ó 2012 Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.jorganchem.2012.05.038

X. Xiao et al. / Journal of Organometallic Chemistry 715 (2012) 54e63
55
97 [13] and refined using SHELXL-97 [14]. All non-hydrogen atoms
were refined with anisotropic temperature parameters; hydrogen
atoms were refined as rigid groups. Crystal data and refinement
results for complexes 1e5 are listed in Table 1.
NMR (CDCl3, ppm):
4H, H2Oe); 7.21e7.69 (m, 38H, AreH); 2.36 (s, 6H, AreCH3). 13C
NMR (CDCl3, ppm): 192.13 (C]O); 169.32 (COO); 144.24, 138.93
(6C, JSneC ¼ 486 Hz), 138.26, 137.01 (12C), 135.86, 135.32, 130.56
(1C), 130.25 (4C), 129.37 (1C), 128.7 (18C), 128.12 (4C) (carbon
protons of aryl groups); 21.48 (AreCH3); (all peaks 2C unless
otherwise noted).
d 8.75 (s, 1H, AreH); 8.21 (s, 1H, AreH); 7.45(s,
d
1
2.3. Syntheses
2.3.1. Syntheses of ligands
2.3.3. Synthesis of (Cy3Sn)2(4,6-L1)(DMF)2 (2)
4,6-H2L1 (meta), 4,6-H2L2 (meta) and 4,6-H2L4 (meta) were
prepared by a standard method reported in the literature [11,15]
(Scheme 1).
The preparation of 2 is similar to that of 1 except that tricyclo-
hexyltin hydroxide (0.77 g, 2 mmol) is used instead of triphenyltin
hydroxide, and the products were recrystallized from dime-
thylformamide instead of ethanol. Yield: 73%; mp: 126e130 ꢁC.
Anal. Calcd for C66H96N2O8Sn2: C, 61.65; H, 7.76; N, 2.18%. Found:
The preparation of 2,5-H2L3 (para) is similar to that of 4,6-H2L1
(meta): pyromellitic dianhydride (4.36 g, 0.02 mol), anhydrous
aluminum chloride (10.67 g, 0.08 mol) and dry cumene (28.80 g,
0.24 mol) were added into a three-neck flask and stirred at
65e70 ꢁC for 3 h in a water-bath. The mixture was then poured into
icewater of concentrated hydrochloric acid. The produced crude
mixtures of acids were left in the form of white solid after the
cumene was completely removed. Washed the crude products with
water, and dissolved them in boiling dilute potassium hydroxide
solution. After the filtration to remove a little insoluble matter, the
mixture of meta and para were obtained after adding hydrochloric
acid (yield: 72.8%). Separated by crystallization from glacial acetic
acid, the para could be obtained first. The meta usually crystallized
upon aqueous dilution of the filtrates [11,16]. The para and meta
isomers are obtained in a ratio of 5:1. For para: mp: 358e363 ꢁC. 1H
C, 61.61; H, 7.72; N, 2.25%. IR (cmꢀ1):
1666; ns(COO) 1443;
(SneO) 458. 1H NMR (CDCl3, ppm):
n
(CeH) 2918, 2844; nas(COO)
8.77(s,
n
d
1H, AreH); 8.27(s, 1H, AreH); 8.02 (s, 2H, HeC]O); 7.18e7.65 (m,
38H, AreH); 2.96 (s, 12H, H3CeNeCH3); 2.38 (s, 6H AreCH3);
1.23e1.76 (m, 66H, CyeH). 13C NMR (CDCl3, ppm):
d 195.10 (C]
O); 171.74 (COO); 161.75 (C]O, DMF); 146.77,130.72,130.17,129.44,
130.25 (1C), 129.88 (1C), 126.92 (4C), 125.57 (4C) (carbon protons of
aryl groups); 21.12 (AreCH3); 34.20 (4C, CeNeC); 33.54 (6C,
1JSneC ¼ 526 Hz); 31.27 (12C); 29.73 (12C); 27.14 (6C) (CyeC); (all
peaks 2C unless otherwise noted).
2.3.4. Synthesis of (Ph3Sn)2(4,6-L2)(DMF)2 (3)
The preparation of 3 is similar to that of 1 except that 4,6-L2
(0.37g, 1 mmol) was used instead of 4,6-L1, and the products were
recrystallized from dimethylformamide instead of ethanol. Yield:
69.2%; mp: 112e115 ꢁC. Anal. Calcd for C64H56N2O8Sn2: C, 63.08; H,
NMR (acetone-d6, ppm):
d
8.08 (s, 2H, AreH); 7.63 (d, 4H, J ¼ 7.8 Hz,
AreH); 7.19 (d, 4H, J ¼ 7.8 Hz, AreH); 2.86e2.71 (m, 2H, eCH); 1.21
(d, 12H, J ¼ 6.9 Hz, eCH3). 13C NMR (acetone-d6, ppm):
d 197.25 (C]
O); 167.86(COO); 148.73, 136.35, 131.27, 130.41, 129.35, 128.67 (4C),
4.63; N, 2.30%. Found: C, 63.13; H, 4.57; N, 2.36%. IR (cmꢀ1):
n
(CeH)
(SneO) 450. 1H NMR
8.86 (s, 1H, AreH); 8.10 (s, 1H, AreH); 8.02 (s, 2H,
HeC]O); 6.91e7.63 (m, 40H, AreH); 2.96 (s,12H, H3CeNeCH3). 13
NMR (CDCl3, ppm): 195.80 (C]O); 170.32 (COO); 162.55 (C]O,
125.26 (4C) (carbon protons of aryl groups); 29.36 (
a
-C of iso-
2927, 2851; nas(COO) 1650; ns(COO) 1428;
(CDCl3, ppm):
n
propyl); 23.14 (4C,
noted).
b-C of isopropyl); (all peaks 2C unless otherwise
d
C
2.3.2. Synthesis of (Ph3Sn)2(4,6-L1)(H2O)2$(C2H5OH)$4H2O (1)
A mixture of triphenyltin hydroxide (0.73 g, 2 mmol) and 4,6-L1
(0.40 g, 1 mmol) was heated under reflux in benzene (30 ml) for
10 h in a DeaneStark apparatus for azeotropic removal of the water
formed in the reaction (Scheme 2). The reaction mixture was
filtered and evaporated to afford the products at room temperature.
The products were then recrystallized from ethanol to give color-
less crystals. Yield: 61%; mp: 118e122 ꢁC. Anal. Calcd for
C62H64O13Sn2: C, 59.35; H, 5.14. Found: C, 59.31; H, 5.11%. IR (cmꢀ1):
d
DMF); 145.33, 142.79, 137.48, 136.65, 133.89 (1C), 133.05 (1C), 131.10
(4C), 129.45 (4C), 129.30 (6C, 1JSneC ¼ 508 Hz), 128.87 (12C), 128.34
(12C); 126.70 (6C) (carbon protons of aryl groups); 36.46 (4C,
CeNeC); (all peaks 2C unless otherwise noted).
2.3.5. Synthesis of (Ph3Sn)2(2,5-L3)(DMF)2 (4)
The preparation of 4 is similar to that of 1 except that 2,5-L3
(0.46 g, 1 mmol) was used instead of 4,6-L1, and the products were
recrystallized from dimethylformamide instead of ethanol. Yield:
n
(CeH) 2922, 2838; nas(COO) 1670; ns(COO) 1449;
n
(SneO) 455. 1H
Table 1
Crystal data and structure refinement parameters for 1e5.
1
2
3
4
5
Empirical formula
M
C62H64O13Sn2
1254.51
Monoclinic
C2/c
18.776(2)
20.587(2)
18.4820(18)
90.00
93.367(2)
90.00
7131.7(12)
4
C66H96N2O8Sn2
1282.83
Monoclinic
P2(1)/c
26.6864(10)
13.3263(6)
18.8596(7)
90.00
91.607(3)
90.00
6704.4(5)
4
C64H56N2O8Sn2
1218.49
Triclinic
P1
13.410(3)
14.679(3)
15.292(4)
73.589(4)
85.040(4)
82.870(3)
2861.0(12)
2
C70H68N2O8Sn2
1302.64
Monoclinic
P2(1)/c
10.7968(13)
16.849(2)
17.118(2)
90.00
90.478(2)
90.00
3114.0(6)
2
C124H208O22Sn8
3000.42
Monoclinic
P2(1)/n
13.9077(14)
19.838(2)
25.950(3)
90.00
102.378(2)
90.00
Crystal system
Space group
ꢀ
a (A)
ꢀ
b (A)
ꢀ
c (A)
a
b
g
(ꢁ)
(ꢁ)
(ꢁ)
3
ꢀ
V (A )
6993.3(12)
2
1.463
Z
m
(mmꢀ1
)
0.751
0.796
0.929
0.858
Reflections collected
Independent reflections
Rint
18,089
6297
0.0701
0.995
39,453
12,563
0.1358
0.867
14,591
9979
0.0452
0.978
15,955
5502
0.0553
1.039
38,895
13m792
0.1485
Goodness-of-fit on F2
0.864
R1, wR2 [I > 2
R1, wR2 (all data)
s
(I)]
0.0631, 0.1754
0.1354, 0.2136
0.0747, 0.1268
0.2093, 0.1558
0.0606, 0.1393
0.1160, 0.1716
0.0620, 0.1344
0.0987, 0.1513
0.0761, 0.1168
0.2380, 0.1599

56
X. Xiao et al. / Journal of Organometallic Chemistry 715 (2012) 54e63
Scheme 1. Syntheses of ligands.
78.2%; mp: 128e131 ꢁC. Anal. Calcd for C70H68N2O8Sn2: C, 64.54; H,
5.26; N, 2.15%. Found: C, 64.51; H, 5.22; N, 2.19%. IR (cmꢀ1):
(CeH)
2961, 2925; nas(COO) 1646; ns(COO) 1430;
(SneO) 452. 1H NMR
(CDCl3, ppm): 8.07 (s, 2H, AreH); 8.01 (s, 2H, HeC]O); 7.10e7.57
(s, 2H, AreH); 6.87e7.59 (m, 16H, AreH); 3.42 (q, 4H, J ¼ 7.2 Hz,
OeCH2e); 2.45 (q, 8H, J ¼ 7.3 Hz, AreCH2e); 1.32 (t, 12C, J ¼ 7.3 Hz,
AreCeCH3); 1.19e1.67 (m, 96H, SneCH2CH2CH2e); 1.10 (t, 6H,
J ¼ 7.2 Hz, OeCeCH3); 0.88 (t, 48H, J ¼ 7.1 Hz, eCH3, Bu). 13C NMR
n
n
d
(m, 38H, AreH); 2.92 (s, 12H, H3CeNeCH3); 1.18e1.28 (m, 2H,
eCHe); 1.05 (d, 12H, J ¼ 6.9 Hz, eCH3). 13C NMR (CDCl3, ppm):
(CDCl3, ppm): d 196.89 (4C, C]O); 171.58 (4C, COO); 146.22 (4C),
142.98 (4C), 134.94 (8C), 134.21 (8C), 133.59 (2C), 130.06 (2C),
129.69 (4C), 125.47 (4C) (carbon protons of aryl groups); 27.44 (16C,
eCH2e), 25.06 (16C, eCH2e), 23.74 (16C, eCH2e, 1JSneC ¼ 614 Hz),
13.94 (16C, eCH3) (carbon protons of butyl groups); 28.62 (4C,
AreCH2e); 16.13 (4C, eCH3) (carbon protons of ethyl groups of 4-
ethylphenyl groups); 55.68 (2C, eCH2e), 16.87 (2C, eCH3) (carbon
protons of alkoxy groups).
d
195.44 (C]O); 170.82 (COO); 162.51(C]O, DMF); 154.44, 137.39,
137.04, 136.71, 134.65, 130.13 (4C), 129.92 (4C), 128.81 (6C,
1JSneC ¼ 465 Hz), 128.38 (12C), 126.44 (12C), 126.08 (6C) (carbon
protons of aryl groups); 36.46 (4C, CeNeC); 34.19 (eCHe); 23.60
(4C, eCH3); (all peaks 2C unless otherwise noted).
2.3.6. Synthesis of [(n-Bu2Sn)4(4,6-L4)O2(OH)(OC2H5)]2$2(C2H5OH)
(5)
3. Results and discussion
The preparation of 5 is similar to that of 1 except that dibutyltin
oxide (0.99 g, 4 mmol) was used instead of triphenyltin hydroxide.
Yield: 69.1%; mp: 296e298 ꢁC. Anal. Calcd for C124H208O22Sn8: C,
3.1. IR spectra
49.63; H, 6.99%. Found: C, 49.67; H, 6.95%. IR (cmꢀ1):
n
(CeH) 2949,
The interesting stretching frequencies of complexes 1e5 are
those associated with COO, SneO and SneOeSn groups. The bands
at 3100e3550 cmꢀ1 which appear in the free ligands H2L1, H2L2,
2919, 2875; nas(COO) 1648, 1610; ns(COO) 1399, 1348;
n
n(SneO) 493;
(SneOeSn) 609. 1H NMR (CDCl3, ppm):
d 8.78 (s, 2H, AreH); 8.11
Scheme 2. Syntheses of complexes 1e5.

X. Xiao et al. / Journal of Organometallic Chemistry 715 (2012) 54e63
57
H2L3 and H2L4 as the
complexes 1e5 and indicates metaleligand bond formation
through these sites [11]. Two absorption bands in the ranges of
1610e1670 cmꢀ1 and 1348e1449 cmꢀ1 can be assigned to nas(COO)
n
(OeH) stretching vibrations are absent in
and ns(COO) respectively. The Δ
n
[
nas(COO) ꢀ ns(COO)] values are
useful for determining the mode of coordinated bonding between
metal and carboxyl. That is, the value smaller than 200 cmꢀ1
indicates that the carboxylate moiety is bidentate, while larger than
200 cmꢀ1 indicates unidentate [17e19]. The magnitude of Δ
n of
216e262 cmꢀ1 for complexes 1e5 indicates the carboxylate ligands
function as monodentate under the conditions employed which is
confirmed by the X-ray structural analysis.
A band in the
450e493 cmꢀ1 region is assigned to the stretching frequency
Table 2
ꢁ
ꢀ
Selected bond lengths (A) and angles ( ) for 1e4.
Complex 1
Bond length
C(10)eSn(1)
C(21)eSn(1)
C(31)eSn(1)
2.121(9)
2.113(8)
2.109(8)
O(1W)eSn(1)
O(3)eSn(1)
2.470(6)
2.142(5)
Bond angles
C(31)eSn(1)eC(21)
C(31)eSn(1)eC(10)
C(21)eSn(1)eC(10)
C(31)eSn(1)eO(3)
C(21)eSn(1)eO(3)
118.3(4)
113.4(3)
126.4(4)
89.2(3)
C(10)eSn(1)eO(3)
C(31)eSn(1)eO(1W)
C(21)eSn(1)eO(1W)
C(10)eSn(1)eO(1W)
O(3)eSn(1)eO(1W)
99.1(3)
85.3(3)
85.4(3)
85.5(3)
173.9(2)
94.9(3)
Complex 2
Bond length
Sn(1)eC(71)
Sn(1)eC(30)
Sn(1)eC(43)
Sn(2)eC(45)
Sn(2)eC(57)
Sn(2)eC(51)
2.116(11)
2.148(9)
2.148(7)
2.139(11)
2.142(9)
2.149(8)
Sn(1)eO(1)
Sn(1)eO(8)
2.146(5)
2.550(6)
Sn(2)eO(6)
Sn(2)eO(7)
2.139(5)
2.528(8)
Bond angles
C(71)eSn(1)eO(1)
C(71)eSn(1)eC(30)
O(1)eSn(1)eC(30)
C(71)eSn(1)eC(43)
O(1)eSn(1)eC(43)
O(6)eSn(2)eC(45)
O(6)eSn(2)eC(57)
C(45)eSn(2)eC(57)
O(6)eSn(2)eC(51)
C(45)eSn(2)eC(51)
96.3(3)
117.3(4)
92.6(3)
122.6(4)
100.2(3)
95.6(4)
C(30)eSn(1)eC(43)
C(71)eSn(1)eO(8)
O(1)eSn(1)eO(8)
C(30)eSn(1)eO(8)
C(43)eSn(1)eO(8)
C(57)eSn(2)eC(51)
O(6)eSn(2)eO(7)
C(45)eSn(2)eO(7)
C(57)eSn(2)eO(7)
C(51)eSn(2)eO(7)
116.4(3)
84.8(3)
173.5(2)
81.2(3)
84.5(3)
113.4(3)
173.9(2)
83.8(4)
81.9(3)
83.3(3)
92.8(3)
114.2(4)
101.8(3)
128.0(4)
Complex 3
Bond length
Sn(1)eC(11)
Sn(1)eO(1)
Sn(1)eC(17)
Sn(1)eC(23)
2.103(7)
2.112(5)
2.123(8)
2.126(8)
2.531(6)
Sn(2)eC(51)
Sn(2)eC(63)
Sn(2)eO(6)
Sn(2)eC(57)
Sn(2)eO(7)
2.099(8)
2.106(8)
2.111(5)
2.136(8)
2.478(6)
Sn(1)eO(8)
Bond angles
C(11)eSn(1)eO(1)
C(11)eSn(1)eC(17)
O(1)eSn(1)eC(17)
C(11)eSn(1)eC(23)
O(1)eSn(1)eC(23)
C(17)eSn(1)eC(23)
C(11)eSn(1)eO(8)
O(1)eSn(1)eO(8)
C(17)eSn(1)eO(8)
C(23)eSn(1)eO(8)
100.5(2)
117.6(3)
90.5(2)
120.5(3)
100.8(3)
117.1(3)
82.6(2)
173.0(2)
82.6(3)
82.8(3)
C(51)eSn(2)eC(63)
C(51)eSn(2)eO(6)
C(63)eSn(2)eO(6)
C(51)eSn(2)eC(57)
C(63)eSn(2)eC(57)
O(6)eSn(2)eC(57)
C(51)eSn(2)eO(7)
C(63)eSn(2)eO(7)
O(6)eSn(2)eO(7)
C(57)eSn(2)eO(7)
129.4(3)
98.1(2)
97.3(3)
113.0(3)
114.4(3)
91.6(3)
85.0(3)
82.1(3)
176.3(2)
85.3(3)
Complex 4
Bond length
Sn(1)eC(11)
Sn(1)eC(17)
Sn(1)eC(23)
2.111(7)
2.119(7)
2.131(7)
Sn(1)eO(2)
Sn(1)eO(4)
2.141(4)
2.409(4)
Bond angles
C(11)eSn(1)eC(17)
C(11)eSn(1)eC(23)
C(17)eSn(1)eC(23)
C(11)eSn(1)eO(2)
C(17)eSn(1)eO(2)
121.2(3)
115.3(3)
121.9(3)
98.3(2)
C(23)eSn(1)eO(2)
C(11)eSn(1)eO(4)
C(17)eSn(1)eO(4)
C(23)eSn(1)eO(4)
O(2)eSn(1)eO(4)
88.6(2)
86.5(2)
83.7(2)
87.5(2)
174.79(17)
Fig. 1. The molecular structures of complexes 1e4.
95.4(2)

58
X. Xiao et al. / Journal of Organometallic Chemistry 715 (2012) 54e63
Fig. 2. 1D chain structure of complex 1. Only relevant phenyl groups and H atoms are drawn for clarity.
associated with the SneO bond. A strong band of 609 cmꢀ1 for
complex 5 is assigned to (SneOeSn) which indicates a SneOeSn
bridged structure [20e22].
slightly longer than the SneO covalent bond length (2.13 A) but
ꢀ
n
much shorter than the sum of the van der Waals radii of the two
atoms (3.68 A) [26]. That indicates a strong coordinating bond
ꢀ
between the solvent oxygen atom and tin atom. In 1e3 the length of
ꢀ
SneO(H2O) [2.470(6) A] is a bit shorter than that of SneO(DMF)
3.2. NMR spectra
ꢀ
[average length: 2.522 A] which prove the coordinating bond
The 1H NMR spectra show the expected integration and peak
multiplicities. The resonance appears at 11e12 ppm in the spec-
trum of free ligands [11] is absent in the spectra of complexes 1e5,
indicating the replacement of the carboxylic acid proton by an
alkyltin moiety in the complex formation [23,24]. The chemical
shifts of the two hydrogen protons on central aromatic rings of
complexes 1e3 and 5 exhibit two different signals at 8.10e8.21 and
8.75e8.86 ppm as single peak, and for complex 4 they exhibit the
same at 8.07 ppm as single peak. Signals for the hydrogen protons
on the other phenyl groups of complexes 1e5 appear at
6.87e7.69 ppm as multiplets and for the hydrogen protons on
cyclohexyl groups of 2 are at 1.23e1.76 ppm as multiplets. Butyl
groups of 5 and solvent peak can also be appropriately attributed.
In the 13C NMR spectra of the complexes 1e5, a significant
downfield shift of all carboxylate carbon resonances compared
with the free ligands is observed. The shift is attributed to the
transferring of electron density from the ligand to the Sn atom [11].
The carbon protons of central aromatic rings present four kinds of
chemical environment in complexes 1e3 and 5 while present three
kinds in complexe 4. The single resonances at 192.12e196.89 and
169.32e171.74 are owing to the C]O and COO groups in complexes
1e5. Solvent peak can also be appropriately assigned. These data
are consistent with the X-ray structures of 1e5. For 1e4, with the
1JSneC values being 465e526 Hz and by the use of the Holecek and
Lycka equation [25], CeSneC values of 117.5e122.9ꢁ were calcu-
lated, which correspond to the geometry of Sn atoms in solid state
of these complexes. For 5, the value is 614 Hz, and CeSneC bond
angle of 130.6ꢁ was calculated which is in accord with the X-ray
structure of 5.
SneO(H2O) is more stable than SneO(DMF) for the smaller steric
hindrance and the stronger electron donating ability of water
ꢀ
molecule. While for 4, it is the shortest [2.409(4) A] among those
lengths due to the reduction of steric hindrance caused by para-
position of two tin atoms. The SneO (carboxylate oxygen atom)
ꢀ
bond lengths of 1e4 are 2.111(5)e2.146(5) A and relative SneC
ꢀ
bond lengths are 2.099(8)e2.149(8) A. These bond lengths and
angles are similar to those of the complexes reported [11]. The
oxygen atoms of carboxylate groups which do not participate in the
coordination to tin atoms are involved in intramolecular interac-
ꢀ
tions with tin with distances (3.096e3.298 A). Considering the
weak Sn/O interaction, the geometry of tin atoms is best described
as distorted octahedron. In 1e3, the distance between two tin
ꢀ
ꢀ
nucleus decrease in the order of 1 (10.903 A) > 3 (10.777 A) > 2
ꢀ
(8.208 A). For 1 and 3, the phenomenon is attributed to the volume
of group (methyl-benzoyl > benzoyl) on central aromatic ring. The
distance of 2 is much shorter than those of 1 and 3 for the flexibility
of cyclohexyl groups on tin. For the same reason, two tin atoms of 2
are almost on the plane of central aromatic ring with slight devi-
ꢀ
ation (0.055 and 0.186 A), while for 1 and 3, tin atoms are located
3.3. Crystal structures
3.3.1. Crystal structures of 1e4
The molecular structures of 1e4 are shown in Fig. 1. Selected
bond lengths and angles are listed in Table 2. Their structures all
contain a binuclear triorganotin skeleton with two tin atoms five
coordinated. Each tin atom demonstrates a distorted trigonal
bipyramidal geometry coordinated with the oxygen atom from
solvent (1: water; 2e4: DMF) and the carboxylate oxygen atom in
the axial sites. The equatorial planes are occupied by three carbon
atoms (1, 3, 4: phenyl carbon; 2: cyclohexyl carbon). The axial
OeSneO angles of 1e4 prove the distortion of the geometry:
173.9(2)ꢁ for 1; 173.5(2)ꢁ and 173.9(2)ꢁ for 2; 173.0(2)ꢁ and
176.3(2)ꢁ for 3; 174.79(17)ꢁ for 4. The distances of SneO (solvent
Fig. 3. 2D network structure of complex 1. Only relevant phenyl groups and H atoms
are drawn for clarity.
ꢀ
oxygen atom) bond of 1e4 are 2.409(4)e2.550(6) A, which are

X. Xiao et al. / Journal of Organometallic Chemistry 715 (2012) 54e63
59
Fig. 4. 3D structure of complex 1. Only relevant groups and H atoms are drawn for clarity. The free ethanol and water molecules adopt space-filling mode to extrude.
Fig. 5. 1D chain structure of complex 2. Only relevant groups and H atoms are drawn for clarity.
Fig. 6. 1D chain structure of complex 3. Only relevant groups and H atoms are drawn for clarity.

60
X. Xiao et al. / Journal of Organometallic Chemistry 715 (2012) 54e63
Fig. 7. 1D chain structure of complex 4. Only relevant groups and H atoms are drawn for clarity.
ꢀ
upon and down the plane of central aromatic ring owing to the
C(13)eH(13A)/O(2) bond with reasonable bond distance 2.524 A
ꢀ
rigidity of the phenyl groups on tin with distances 0.952e1.126 A.
[27]. With these kind of bonds the molecules generate an inter-
molecular macrocycle (A) which can be considered as a parallelo-
gram for the parallel relationship of the phenyl groups on the
opposite sides. The width of the cavity can be evaluated by the
ꢀ
For complex 4, Sn/Sn distance is 11.481 A. Without much steric
hindrance for para-position, tin atoms lie on the plane of central
aromatic ring.
Beside the bonds mentioned above, for complex 1, intermolec-
ular hydrogen bonds are formed. In Fig. 2, O(2) of the carbanyl
group and H(13A) from the phenyl groups on tin are connected by
ꢀ
diagonal Sn/Sn and C/C distances, which is 10.911 ꢂ 13.710 A.
Complex 1 demonstrates as a 1D chain along c axis via these
hydrogen bonds. As shown in Fig. 3, H(25A) from phenyl group and
Fig. 8. 2D network of complex 3. Only relevant groups and H atoms are drawn for clarity.
Fig. 9. 2D network of complex 4. Only relevant groups and H atoms are drawn for clarity.

X. Xiao et al. / Journal of Organometallic Chemistry 715 (2012) 54e63
61
Fig. 10. Molecular structure of complex 5.
O(2) of the carbanyl group are also bonded by C(25)eH(25A)/O(2)
ꢀ
hydrogen bond with bond length 2.472 A. These type of bonds help
the molecules form a new irregular 46-membered macrocycle (B)
and link them into a 2D network on ab-plane. A and B are con-
nected with each other by the two types of hydrogen bonds
mentioned forming a 3D architecture (Fig. 4). Free ethanol and
water molecules are situated in the intermolecular channels
disorderly.
Table 3
ꢁ
ꢀ
Selected bond lengths (A) and angles ( ) for 5.
Bond length
Sn(1)eO(4)
Sn(1)eO(3)
Sn(1)eO(5)
Sn(1)eC(35)
Sn(1)eC(31)
Sn(2)eO(5)
Sn(2)eO(6)
Sn(2)eO(4)
Sn(2)eC(41)
Sn(2)eC(45)
Bond angles
2.037(7)
2.243(8)
2.113(7)
2.042(14)
2.050(12)
2.022(7)
2.140(7)
2.173(7)
2.070(14)
2.114(14)
Sn(3)eO(6)
Sn(3)eO(8)
Sn(3)eO(7)
Sn(3)eC(61)
Sn(3)eC(65)
Sn(4)eO(6)
Sn(4)eO(5)
Sn(4)eO(7)
Sn(4)eC(51)
Sn(4)eC(55)
2.014(7)
2.153(7)
2.224(8)
2.060(14)
2.096(12)
2.023(7)
2.115(7)
2.165(8)
2.035(14)
2.092(13)
For complex 2 (Fig. 5), H(37C) and H(44B) derived from methyl
groups of the coordinating DMF and O(2) from the carbanyl group
ꢀ
are interacted by C(37)eH(37C)/O(2) (2.633 A) and C(44)e
ꢀ
H(44B)/O(2) (2.431 A) hydrogen bonds. Through the connection
of these bonds, complex 2 can be described as a 1D zig-zag infinite
chain.
In complexes 3 and 4, CeH/p interactions play an important
role on the supramolecular structures. It can be seen from Figs. 6
and 7 that 3 and 4 assume 1D chain structure via that interaction.
The pi electrons are from the phenyl group on tin atom. The
hydrogen atom is from the coordinating DMF for 3 and isopropyl
group for 4. For complex 3, intermolecular hydrogen bonds C(21)e
H(21A)/O(3) (2.474 A) link the chains into a 2D network (Fig. 8).
H(21A) is derived from the phenyl group and O(3) is from carbanyl
group. For complex 4, the CeH/p interactions along b axis help the
chains (along c axis) link into a 2D network architecture (bc-plane)
O(4)eSn(1)eO(5)
O(4)eSn(1)eO(3)
O(5)eSn(1)eO(3)
O(4)eSn(1)eC(35)
O(4)eSn(1)eC(31)
C(35)eSn(1)eO(5)
C(31)eSn(1)eO(5)
C(35)eSn(1)eO(3)
C(31)eSn(1)eO(3)
C(35)eSn(1)eC(31)
O(6)eSn(3)eO(8)
O(6)eSn(3)eO(7)
O(8)eSn(3)eO(7)
O(6)eSn(3)eC(61)
O(6)eSn(3)eC(65)
C(61)eSn(3)eO(8)
C(65)eSn(3)eO(8)
C(61)eSn(3)eO(7)
C(65)eSn(3)eO(7)
C(61)eSn(3)eC(65)
73.7(3)
84.8(3)
158.5(3)
111.2(5)
111.5(4)
97.0(4)
97.5(4)
89.4(4)
91.4(4)
137.2(5)
80.5(3)
71.5(3)
151.8(3)
114.5(5)
114.0(4)
97.7(5)
98.4(4)
91.2(5)
95.8(4)
130.6(5)
O(5)eSn(2)eO(6)
O(5)eSn(2)eO(4)
O(6)eSn(2)eO(4)
O(5)eSn(2)eC(41)
O(5)eSn(2)eC(45)
C(41)eSn(2)eO(6)
C(45)eSn(2)eO(6)
C(41)eSn(2)eO(4)
C(45)eSn(2)eO(4)
C(41)eSn(2)eC(45)
O(6)eSn(4)eO(5)
O(6)eSn(4)eO(7)
O(5)eSn(4)eO(7)
O(6)eSn(4)eC(51)
O(6)eSn(4)eC(55)
C(51)eSn(4)eO(5)
C(55)eSn(4)eO(5)
C(51)eSn(4)eO(7)
C(55)eSn(4)eO(7)
C(51)eSn(4)eC(55)
74.4(3)
72.7(3)
147.1(3)
114.9(5)
116.3(4)
97.6(4)
96.6(5)
94.9(4)
99.1(4)
128.8(6)
74.9(3)
72.6(3)
147.5(3)
114.7(5)
115.3(4)
98.6(4)
97.6(4)
95.4(5)
95.7(4)
129.8(5)
ꢀ
(Fig. 9).
3.3.2. Crystal structure of 5
The structure of complex 5 is shown in Fig. 10. Selected bond
distances and angles are listed in Table 3. The structure of 5 is based
on two novel Sn4O4 ladders connected by two carboxylate ligands
and features a centrosymmetric macrocycle (A) which is similar to
the complexes reported in the literature [11]. There exist two types

62
X. Xiao et al. / Journal of Organometallic Chemistry 715 (2012) 54e63
Fig. 11. 2D network of complex 5. Only relevant groups and H atoms are drawn for clarity.
of tin atoms according to their different chemical environments:
the endocyclic tin [Sn(2) and Sn(3)] and the exocyclic tin [Sn(1) and
Sn(4)]. The endocyclic and exocyclic tin atoms are connected by the
m3-oxygen atoms [O(5) and O(6)] and the m2-oxygen atoms [O(4)
and ethanolic oxygen O(7)] forming the ladder structure. The four
tin atoms of Sn4O4 ladder are almost coplanar with deviations
Acknowledgments
We acknowledged the Postdoctoral Science foundation P.R.
China (No. 2005038561).
Appendix A. Supplementary material
ꢀ
0.014e0.069 A. All of the tin atoms adopt the distorted trigonal
bipyramidal geometry. They are five-coordinated with two n-Bu
groups and one O atom in equatorial positions and another two O
atoms in axial positions. The axial OeSneO angles range from
147.10(3)ꢁ to 158.50(3)ꢁ and deviate considerably from 180ꢁ, which
indicate the distortion of the geometry. The distortions are partly
owing to the rigid framework of the ladders. Each carboxylate
group of the ligands coordinates with an exocyclic Sn atom [Sn(1)
and Sn(3)] at both ends of the ladders in the monodentate mode
and generate a macrocycle. The insertion of m2-OCH2CH3 group can
be interpreted by the higher donor capacity of alkoxyl group than
the carboxylate group of 4,6-L4 [28,29].
CCDC 717710, 842978, 842985, 842986 and 717705 for
complexes 1e5 contain the supplementary crystallographic data
for this paper. These data can be obtained free of charge from The
Cambridge Crystallographic Data Center via www.cccdc.cam.ac.uk/
data-request/cif.
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