Preparation, Structure and Optical Properties of
[CH3 SC(NH2 )2 ]3 SnI5, [CH3 SC(NH2 )2 ][HSC(NH2 )2 ]SnBr4 ,
(CH3 C5 H4 NCH3 )PbBr3 , and [C6 H5 CH2 SC(NH2 )2 ]4 Pb3 I10
C. P. Raptopouloua , A. Terzisa , G. A. Mousdisb , and G. C. Papavassilioub
a
b
Institute of Materials Science, NCSR, Demokritos, Athens 153/10, Greece
Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation,
48, Vassileos Constantinou Ave., Athens 116/35, Greece
Reprint requests to Prof. G. C. Papavassiliou. Fax: (3010) 7273794
Z. Naturforsch. 57 b, 645–650 (2002); received February 14, 2002
Metal Halides, Excitonic Spectra, Optical Properties
The preparation, crystal structure and optical absorption spectra of [CH3 SC(NH2 )2 ]3 SnI5
(1), [CH3 SC(NH2 )2 ][HSC(NH2)2 ]SnBr4 (2), (CH3 C5 H4 NCH3 )PbBr3 (3), and [C6 H5 CH2 SC(NH2)2 ]4 Pb3 I10 (4) are reported. The compounds 1, 2, 3 consist of MX6 -octahedra (M = Sn,
Pb, X = I, Br) forming one-dimensional single chains (compounds 1, 3) or double chains
(compound 2). The compound 4 forms a two-dimensional inorganic network via corner sharing
of three face sharing octahedral units. Because of their low-dimensional character, a blue shift
of the excitonic absorption bands, in comparison to those of higher dimensionality systems, is
observed.
Introduction
Recently, much attention has been devoted to
low-dimensional organic-inorganic hybrid materials of the type (A)x My Xz (where A is amine-H+
or 1/2diamine-2H+ ; M = Sn, Pb, etc; X = I, Br,
Cl) in which the inorganic part forms three- or
lower-dimensional networks (see [1 - 4] and refs
therein). These compounds are the subject of various fundamental as well as more applied studies
related to their structural [1, 3], linear and nonlinear optical [1, 3, 5], transport [6] and other
physical properties [7]. Their structures are characterized by MX6 octahedra sharing corners, edges,
or faces forming slabs, chains or clusters separated by the amine cations. The type of amine defines the dimensionality of the structure. The most
rare structure is the one-dimensional (1D). To the
best of our knowledge, for the Sn family only the
[NH2 C(I)=NH2 ]3 SnI5 salt has been reported with
1D structure (see [2]).
Here, we report the synthesis, structure and
UV-vis optical absorption spectra of four new
salts [CH3 SC(NH2 )2 ]3 SnI5 (1), [CH3 SC(NH2 )2 ][HSC(NH2 )2 ]SnBr4 (2), (CH3 C5 H4 NCH3 )PbBr3
(3) and [C6 H5 CH2 SC(NH2 )2 ]4 Pb3 I10 (4).
Experimental Section
Starting materials and apparatus
The following starting materials were used without
further purification. SnI2 (Alfa 71112), SnBr2 (Johnson
Matthey), PbO (Ferak 01-881), hydroiodic acid, 57%
(Merck 341), hydrobromic acid 47% (Merck 304), 1,4dimethylpyridinium iodide (Aldrich 37,643-4) and similar materials (see also [8, 9]).
Elemental analyses were performed on a Perkin 2400
(II) autoanalyser.
Crystal X-ray intensity data were collected at room
temperature on a Crystal Logic [10] dual goniometer using graphite-monochromated Mo-Kÿ radiation. Unit cell
dimensions were determined and refined by using the angular setting of 24 automatically centered reflections in
the range 11ÿ < 2ÿ < 23ÿ . Intensity data were recorded
using a ÿ-2ÿ scan for: [CH3 SC(NH2 )2 ]3 SnI5 , 2ÿmax = 50ÿ ,
scan speed 3.5ÿ minþ1 , scan range 2.3ÿ plus þ1 þ2 -separation, data collected / unique / used 4223 / 2186 (Rint =
0.020) / 2186; for [CH3 SC(NH2 )2 ][HSC(NH2)2 ]SnBr4 ,
2ÿmax = 50ÿ , scan speed 3.0 ÿ minþ1 , scan range 2.2ÿ plus
þ1 þ2 separation, data collected / unique / used 2957 / 2681
(Rint = 0.0513)/2681; for (CH3 C5 H4 NCH3 )PbBr3 , 2ÿmax =
50ÿ , scan speed 2.7 ÿ minþ1 , scan range 2.3ÿ plus þ1 þ2 separation, data collected / unique / used 2232 / 2232 (Rint =
0.0000) / 2232; and for [C6 H5 CH2 SC(NH2 )2 ]4 Pb3 I10
2ÿmax = 50ÿ , scan speed 2.0 ÿ minþ1 , scan range 2.2ÿ
c 2002 Verlag der Zeitschrift für Naturforschung, Tübingen þ www.znaturforsch.com
0932–0776/02/0600–0645 $ 06.00 ÿ
K
646
Compound
Fw
a (Å)
b (Å)
c (Å)
V (Å3 )
ÿ (deg)
Z
Dcalcd (g/cm3 )
Space group
GOF
R1 /wR2
C. P. Raptopoulou et al. · Four New Organic-Inorganic Hybrid Salts
1
1026.66
13.714(6)
9.949(4)
18.600(8)
2538(2)
2
605.61
6.052(3)
19.549(9)
13.179(6)
1559(1)
90.11(1)
4
4
2.687
2.579
Pnam
P 21 /c
1.206
1.070
0.0295/0.0769a 0.0528/0.1077b
Table 1. Summary of crystal, intensity collection and
refinement data.
3
1110.16
17.30(1)
19.47(1)
7.918(6)
2668(3)
4
2559.56
9.205(4)
20.68(1)
31.80(1)
6054(4)
4
2.687
Pcab
1.035
0.0743/0.1901c
4
2.808
Pcab
1.102
0.0521/0.1274d
For 2058 refs with I > 2ü (I);
for 2232 refs with I > 2ü (I);
c
for 1421 refs with I > 2ü (I);
d
for 3919 refs with I > 2ü (I).
a
b
Table 2. Selected bond lengths (Å) and angles (ÿ ) for 1.
Table 4. Selected bond lengths (Å) and angles (ÿ ) for 3.
Sn-I(1)
3.243(1)
Sn-I(2')
3.138(1)
Sn-I(1')
3.243(1)
Sn-I(3)
2.921(1)
Sn-I(2)
3.138(1)
Sn-I(3'')
4.042(1)
I(2)-Sn-I(3)
92.15(2)
I(3)-Sn-I(2')
92.15(2)
I(2)-Sn-I(2')
90.79(4)
I(3)-Sn-I(1')
90.57(3)
I(2)-Sn-I(1')
89.37(4)
I(3)-Sn-I(1)
90.57(3)
I(2)-Sn-I(1)
177.27(3)
I(3)-Sn-I(3'')
159.72(2)
I(2)-Sn-I(3'')
102.0(1)
I(2')-Sn-I(1')
177.27(3)
I(2')-Sn-I(1)
89.37(4)
I(1)-Sn-I(3'')
75.31(1)
I(2')-Sn-I(3'')
102.0(1)
I(1)-Sn-I(1')
90.35(1)
Symmetry transformations used to generate equivalent atoms: (')
x, y, 1.5 – z, ('') 0.5 + x, 0.5 – y, z.
Pb(1)-Br(1)
Pb(1)-Br(1')
Pb(1)-Br(2)
Br(2)-Pb(1)-Br(3)
Br(2)-Pb(1)-Br(3')
Br(3)-Pb(1)-Br(3')
Br(2)-Pb(1)-Br(1)
Br(3)-Pb(1)-Br(1)
Br(3')-Pb(1)-Br(1)
Br(2)-Pb(1)-Br(2')
Br(3)-Pb(1)-Br(2')
ÿ
Table 3. Selected bond lengths (Å) and angles ( ) for 2.
Sn-Br(1)
3.423(2)
Sn-Br(3)
2.700(2)
Sn-Br(1')
3.088(2)
Sn-Br(3'')
3.370(2)
Sn-Br(2)
2.734(2)
Sn-Br(4)
2.921(2)
Br(1')-Sn-Br(1)
102.95(3)
Br(1)-Sn-Br(4)
79.41(3)
Br(1')-Sn-Br(2)
84.10(2)
Br(2)-Sn-Br(3)
90.57(3)
Br(1')-Sn-Br(3)
87.02(3)
Br(2)-Sn-Br(3'')
85.10(3)
Br(1')-Sn-Br(3'')
100.15(3)
Br(2)-Sn-Br(4)
93.44(3)
Br(1')-Sn-Br(4)
176.87(3)
Br(3)-Sn-Br(3'')
171.18(3)
Br(1)-Sn-Br(2)
172.35(4)
Br(3)-Sn-Br(4)
91.08(3)
Br(1)-Sn-Br(3)
86.88(3)
Br(3'')-Sn-Br(4)
81.53(3)
Br(1)-Sn-Br(3'')
96.43(2)
Symmetry transformations used to generate equivalent atoms: (')
–x, 1 – y, 1 – z, ('') 1 + x, y, z.
plus þ1 þ2 separation, data collected / unique / used 5320
/ 5317 (Rint = 0.0207) / 5317.
Three standard reflections monitored every 97 reflections showed less than 3% variation and no systematic
decay. Lorentz, polarization and absorption corrections
were applied using Crystal Logic Software. The structures
were solved by Patterson methods using SHELXS-86 [11]
and refined by full-matrix least-squares techniques with
SHELXL-93 [12]. All non-hydrogen atoms were refined
anisotropically. Hydrogen atoms in 1 and 2 were located
by difference maps and were refined isotropically, while
in 3 and 4 all H-atoms were introduced at calculated positions as riding on bonded atoms.
3.133(2)
3.206(3)
3.051(3)
83.43(8)
97.14(8)
178.99(8)
85.01(8)
87.22(8)
93.65(8)
94.21(9)
97.82(8)
Pb(1)-Br(2')
Pb(1)-Br(3)
Pb(1)-Br(3')
Br(3')-Pb(1)-Br(2')
Br(1)-Pb(1)-Br(2')
Br(2)-Pb(1)-Br(1')
Br(3)-Pb(1)-Br(1')
Br(3')-Pb(1)-Br(1')
Br(1)-Pb(1)-Br(1')
Br(2')-Pb(1)-Br(1')
3.145(3)
3.085(3)
3.122(3)
81.32(8)
174.78(6)
175.38(6)
94.05(8)
85.32(8)
98.76(8)
82.28(8)
Symmetry transformations used to generate equivalent atoms: (')
0.5 – x, y, 0.5 – z.
Table 5. Selected bond lengths (Å) and angles (ÿ ) for 4.
Pb(1)-I(1)
Pb(1)-I(2)
Pb(1)-I(3)
Pb(1)-I(3'')
Pb(1)-I(4)
Pb(1)-I(5')
I(3)-Pb(1)-I(2)
I(3)-Pb(1)-I(5')
I(2)-Pb(1)-I(5')
I(3)-Pb(1)-I(3'')
I(2)-Pb(1)-I(3'')
I(5')-Pb(1)-I(3'')
I(3)-Pb(1)-I(1)
I(2)-Pb(1)-I(1)
I(1)-Pb(1)-I(5')
I(3'')-Pb(1)-I(1)
I(3)-Pb(1)-I(4)
I(2)-Pb(1)-I(4)
I(4)-Pb(1)-I(5')
I(3'')-Pb(1)-I(4)
I(1)-Pb(1)-I(4)
3.298(2)
3.150(3)
3.097(2)
3.197(2)
3.338(2)
3.173(2)
90.69(3)
88.43(5)
96.60(3)
96.27(4)
84.32(3)
175.21(4)
87.12(3)
172.70(3)
90.24(3)
89.06(3)
171.08(4)
96.36(3)
85.35(5)
89.87(5)
86.52(3)
Pb(2)-I(1)
Pb(2)-I(1')
Pb(2)-I(4)
Pb(2)-I(4')
Pb(2)-I(5)
Pb(2)-I(5')
I(1)-Pb(2)-I(1')
I(1)-Pb(2)-I(4)
I(4)-Pb(2)-I(1')
I(1)-Pb(2)-I(4')
I(4')-Pb(2)-I(1')
I(4)-Pb(2)-I(4')
I(1)-Pb(2)-I(5')
I(5')-Pb(2)-I(1')
I(4)-Pb(2)-I(5')
I(4')-Pb(2)-I(5')
I(1)-Pb(2)-I(5)
I(5)-Pb(2)-I(1')
I(4)-Pb(2)-I(5)
I(5)-Pb(2)-I(4')
I(5)-Pb(2)-I(5')
3.215(2)
3.215(2)
3.227(1)
3.227(1)
3.243(1)
3.243(1)
180.0
89.82(3)
90.18(3)
90.19(3)
89.81(3)
180.0
90.50(3)
89.50(3)
86.08(4)
93.20(4)
89.50(3)
90.50(3)
93.92(4)
86.08(4)
180.0
Symmetry transformations used to generate equivalent atoms: (')
–x, 1 – y, 1 – z, ('') 0.5 – x, 1.5 – y, z.
Crystallographic information files have been deposited in the Cambridge Crystallographic Data Center, 12 Union Road, Cambridge CB2 1EZ UK (e-mail:
C. P. Raptopoulou et al. · Four New Organic-Inorganic Hybrid Salts
647
Fig. 1. Packing diagram of [CH3SC(NH2 )2 ]3 SnI5 (1).
[email protected]) Deposition numbers CCDC
179333 for [CH3 SC(NH2)2 ]3 SnI5 , CCDC 179334 for
[CH3 SC(NH2)2 ][HSC(NH2)2 ]SnBr4 , CCDC 179335 for
(CH3 C5 H4 NCH3 )PbBr3 , and CCDC 179336 for [C6 H5 CH2 SC(NH2 )2 ]4 Pb3 I10 , respectively.
The room temperature optical absorption spectra were
recorded by a Perkin Elmer model Lambda 19 UV-visNIR spectrometer.
Preparation of compounds
The preparations of precursors CH3 SC(NH2 )2 I and
CH3 SC(NH2 )2 Br are reported elsewhere [13].
[CH3SC(NH2 )2 ]3 SnI5 (1) was prepared by refluxing an
aq. HI 57% (10 ml) solution of SnI2 (120 mg, 0.32 mmol)
and CH3 SC(NH2 )2 I (210 mg, 0.96 mmol) under N2 for
0.5 h. The solution was cooled to 2 ÿC and 250 mg of the
product was precipitated as yellow crystals, in a yield of
75%; Analysis for C6 H21N6 I5 S3 Sn (1027): calcd. C 7.02,
H 2.06, N 8.19; found C 6.95, H 2.17, N 8.06.
[CH3SC(NH2 )2 ][HSC(NH2)2 ]SnBr4 (2) was prepared
by refluxing an aq. HBr 47% (10ml) solution of SnBr2
(100 mg, 0.36 mmol) and CH3 SC(NH2 )2 Br (270 mg,
1.08 mmol) under N2 for 0.5 h. The solution was cooled to
2 ÿC and 150 mg of the product was precipitated as yellow
crystals, in a yield of 40%; Analysis for C6 H21 N6 I5 S3 Sn
(607): calcd. C 5.94, H 1.99, N 9.24; found C 6.06, H
2.17, N 9.08.
(CH3C5 H4 NCH3 )PbBr3 (3) was prepared as follows:
To a solution of PbO (312.2 mg, 1.4 mmol) in aq. HBr
47% (2 ml) a solution of 1,4-dimethylpyridinium iodide
(329 mg 1.4 mmol)) in aq. HBr 47% (2 ml) was added
at reflux temperature. The mixture was cooled slowly
to room temperature, to give white crystals in a yield of
Fig. 2. Packing diagram of [CH3 SC(NH2 )2 ][HSC(NH2)2 ]SnBr4 (2).
470 mg (60.5%); Analysis for C7 H10 NBr3 Pb (555): calcd.
C 15.13, H 1.80, N 2.52; found C 14,90, H 1.88, N 2.43.
[C6 H5 CH2 SC(NH2 )2 ]4 Pb3 I10 (4) was prepared by a
slight modification of the method reported in [8]. To
a solution of PbO (334.5 mg, 1.5 mmol) in aq. HI
57% (4.5 ml) and CH3 OH (5 ml) containing H3 PO2 ,
C6 H5 CH2 SC(NH2)2 I (588 mg) was added at once and
the mixture was heated to reflux. By slow cooling yellow
plates were obtained, filtered and air dried; yield 820 mg
(64%); Analysis for C32 H44 N8 I10 S4 Pb3 (2559): calcd. C
15.01, H 1.73, N 4.38; found C 14.96, H 1.71, N 4.32.
Results and Discussion
Morphology of materials
Compounds 1 - 4 were prepared as pure single
crystals, large enough for X-ray crystal structure
determination.
Crystal structures
A summary of crystal data of the compounds at
room temperature is given in Table 1.
[CH3 SC(NH2 )2 ]3 SnI5 (1) is isostructural with the
Pb analogue [13]. It crystallizes in the orthorhombic
system. As can be seen from the packing diagram of
648
C. P. Raptopoulou et al. · Four New Organic-Inorganic Hybrid Salts
Fig. 3. Packing diagram of (CH3C5 H4 NCH3 )PbBr3 (3.
Fig. 1, it consists of distorted SnI6 octahedra. This
distortion is caused by the 5s2 non bonding lone
pair electrons of Sn2+ , resulting in a non-spherical
charge distribution around tin cations and a lowering of the coordination symmetry. Each octahedron
shares opposite corners [I(3) atoms], to give infinite
one-dimensional chains extending along the a axis.
The Sn-I(3)-Sn angle is 175.8þ indicating that the
chain is almost linear. The structure is similar to that
of [NH2 C(I)=NH2 ]3 SnI5 [2, 14], but in our case the
octahedra are more distorted. The two C-N bond
lengths are almost equal indicating that the cations
have a resonance structure [CH3 SC(::: NH2 )2 ]. Selected bond lengths and angles for 1 are given in
Table 2.
[CH3 SC(NH2 )2 ][HSC(NH2 )2 ]SnBr4 (2) crystallizes in the monoclinic system. As is shown in the
packing diagram (Fig. 2), it consists of two edgesharing distorted SnBr6 octahedra [Sn-Br(1)-Sn =
77.05(3)þ ] which are corner-connected to each other
[through Br(3), Sn-Br(3)-Sn = 171.18(3)þ ] to form
infinite double chains along the a axis. The two
C-N bond lengths are almost equal [N(1)-C(2) =
1.30(1), N(2)-C(2) = 1.27(1), N(3)-C(4) = 1.30(1),
Fig. 4. Packing diagram (a) and inorganic layer (b) of
[C6 H5 CH2 SC(NH2 )2 ]4 Pb3 I10 (4), with the atomic labels.
N(4)-C(4) = 1.31(1) Å] indicating that the cations
have a resonance structure [CH3 SC(::: NH2 )2 ]. Selected bond lengths and angles for 2 are given in
Table 3.
(CH3 C5 H4 NCH3 )PbBr3 (3) crystallizes in the orthorhombic system. As can be seen from the packing diagram of Fig. 3, the structure consists of facesharing PbBr6 octahedra [Pb-Br(1)-Pb = 77.29(7),
Pb-Br(2)-Pb = 79.42(8), Pb-Br(3)-Pb = 79.27(8)þ ]
forming one-dimensional chains along the c axis.
Selected bond lengths and angles for 3 are given in
Table 4.
C. P. Raptopoulou et al. · Four New Organic-Inorganic Hybrid Salts
Fig. 5. Optical absorption spectra of thin deposits
of [CH3 SC(NH2 )2 ]3 SnI5 (1) (a) and [CH3 SC(NH2)2 ][HSC(NH2)2 ]SnBr4 (2) (b).
[C6 H5 CH2 SC(NH2 )2 ]4 Pb3 I10 (4) crystallizes in
the orthorhombic system. As shown in Fig. 4, the
structure consists of alternating inorganic and organic layers. The inorganic layers are parallel to the
ab plane and consist of corner sharing trinuclear
units (through I(3), Pb(1)-I(3)-Pb(1') = 159.01(5)þ )
that are formed by three face sharing PbI6 octahedra (through I(1), I(4) and I(5), Pb(2)-I(1)-Pb(1) =
72.96(3), Pb(2)-I94)-Pb(1) = 72.27(3) and Pb(1)I(5)-Pb(2) = 74.24(3)þ ). To our knowledge no other
related material presents this kind of structure. Selected bond lengths and angles for 4 are given in
Table 5.
649
Fig. 6. Optical absorption spectra of thin deposits of
(CH3 C5 NH4 CH3 )PbBr3 (3) (a) and (CH3 C5 H4 NCH3 )Br
(b), for comparison.
Optical properties
The room temperature optical absorption (OA)
spectra of thin deposits of compounds 1, 2, and 3
on quartz plates are shown in Fig. 5 and Fig. 6. The
spectrum of 1 exhibits a double excitonic band at
350 - 380 nm (Fig. 5a), while 2 has this feature at
290 - 327 nm (Fig. 5b). The spectrum of 3 shows
an excitonic band at 359 nm (Fig. 6a), which occurs
close to the low frequency OA band of the organic
component (CH3 C5 H4 NCH3 )Br (i. e., at 314 nm)
(Fig. 6b). The OA spectra of 4 has been reported
in [8]. It shows an excitonic band at 438 nm and
another one at 392 nm, the origin of which is not
understood.
It is observed that the optical properties of these
new compounds are similar to those found for similar compounds based on alkylamines or aryl-alkylamines (see [1 - 4] and refs cited therein).
[1] T. Ishihara, in Y. Kanemitsu (eds): Optical Properties
of Low-Dimensional Materials, ch. 6, pp. 288-339,
World Science, Singapore (1995).
[2] D. B. Mitzi, Progr. Inorg. Chem. 48, 1 (1999).
[3] G. C. Papavassiliou, Progr. Solid State Chem. 25,
125 (1997).
[4] (a) G. C. Papavassiliou, G. A. Mousdis, I. B. Koutselas, Z. Naturforsch. 56b, 57 (2001); (b) Adv. Mater.
Opt. Electron. 9, 265 (1999); (c) G. C. Papavassiliou,
G. A. Mousdis, C. P. Raptopoulou, A. Terzis, Z. Naturforsch. 54b, 1405 (1999); (d) I. B. Koutselas, PhD
Thesis., University of Athens (1998).
[5] T. Kondo, S. Iwamoto, S. Hayase, K. Tanaka, J. Ishi,
M. Mizuno, K. Ema, R. Ito, Sol. State Commun. 105,
503 (1998).
[6] C. R. Kagan, D. B. Mitzi, C. D. Dimitrakopoulos,
Science 286, 945 (1999).
[7] T. Hattori, T. Taira, M. Era, T. Tsutsui, S. Saito,
Chem. Phys. Lett. 254, 103 (1996). T. Gebauer,
G. Schmid, Z. Anorg. Allg. Chem. 625, 1124 (1999);
K. Chondrudis, D. B. Mitsi, Chem. Mater. 11, 3028
(1999).
[8] G. C. Papavassiliou, G. A. Mousdis, I. B. Koutselas,
Naturforsch. 56b, 57 (2001).
650
C. P. Raptopoulou et al. · Four New Organic-Inorganic Hybrid Salts
[9] G. C. Papavassiliou, G. A. Mousdis, I. B. Koutselas,
Naturforsch. 56b, 213 (2001).
[10] Crystal Logic Inc., 10573 w. Pico Blvd., Suite 106,
Los Angeles, CA 90064.
[11] G. M. Sheldrick, SHELXS 86, Structure Solving Program, University of Goettingen, Germany
(1986).
[12] G. M. Sheldrick, SHELXL 93, Crystal Structure
Refinement, University of Goettingen, Germany
(1993).
[13] G. A. Mousdis, V. Gionis, G. C. Papavassiliou, C. P.
Raptopoulou, A. Terzis, J. Mater. Chem. 8, 2259
(1998).
[14] D. B. Mitzi, K. Liang, S. Wang, Inorg. Chem. 37,
321 (1998).