Poly[bis(phenethyl­ammonium) [di­bromido­plumbate(II)]-di-μ-bromido]]

Kengo Shibuya; Masanori Koshimizu; Fumihiko Nishikido; Haruo Saito; Shunji Kishimoto

doi:10.1107/S160053680903712X

. 2009 Oct 7;65(Pt 11):m1323–m1324. doi: 10.1107/S160053680903712X

Poly[bis(phenethylammonium) [dibromidoplumbate(II)]-di-μ-bromido]]

Kengo Shibuya ^a,^b,^*, Masanori Koshimizu ^b,^c, Fumihiko Nishikido ^b,^d, Haruo Saito ^a,^b, Shunji Kishimoto ^b,^e

PMCID: PMC2970995 PMID: 21578085

Abstract

Crystals of the title compound, {(C₆H₅C₂H₄NH₃)₂[PbBr₄]}_n, were grown at room temperature from a solution in N,N-dimethylformamide (DMF) using nitromethane as the poor solvent. This perovskite-type organic–inorganic hybrid compound consists of well ordered sheets of corner-sharing disordered PbBr₆ octahedra separated by bilayers of phenethylammonium cations. The octahedra are rotated and tilted due to N—H⋯Br hydrogen bonds with the ammonium groups, generating a superstructure in the unit cell similar to that of the tetrachloridoplumbate (C₆H₅C₂H₄NH₃)₂[PbCl₄].

Related literature

The title compound has been studied previously and the lattice parameters reported without the complete structure (Mitzi, 1999 ▶). The optical characteristics have been investigated using thin films, see: Cheng et al. (2005 ▶); Kitazawa & Watanabe (2005 ▶). Promising applications have been reported on electroluminescent devices and scintillators, see: Era et al. (1995 ▶); Kishimoto et al. (2008 ▶); van der Eijk et al. (2008 ▶). Structural data of some related materials have been published; for (C₆H₅C₂H₄NH₃)₂PbCl₄, see: Mitzi (1999 ▶); for (C₆H₅C₂H₄NH₃)₂CuBr₄, see: Willett (1990 ▶); for (C₆H₅C₂H₄NH₃)₂ZnBr₄, see: Huh et al. (2006 ▶); for (C₆H₅C₂H₄NH₃)PbBr₃, see: Billing & Lemmerer (2003 ▶). For van der Waals radii, see: Bondi (1964 ▶). For halogen hydrogen bonding, see: Chapuis et al. (1976 ▶).

Experimental

Crystal data

(C₈H₁₂N)₂[PbBr₄]
M _r = 771.20
Triclinic,
a = 11.6150 (4) Å
b = 11.6275 (5) Å
c = 17.5751 (6) Å
α = 99.5472 (12)°
β = 105.7245 (10)°
γ = 89.9770 (12)°
V = 2250.62 (15) Å³
Z = 4
Mo Kα radiation
μ = 14.63 mm⁻¹
T = 296 K
0.25 × 0.20 × 0.03 mm

Data collection

Rigaku R-AXIS RAPID diffractometer
Absorption correction: numerical (ABSCOR; Higashi, 1999 ▶) T _min = 0.106, T _max = 0.645
20072 measured reflections
10077 independent reflections
7157 reflections with I > 2σ(I)
R _int = 0.053

Refinement

R[F ² > 2σ(F ²)] = 0.042
wR(F ²) = 0.106
S = 0.97
10077 reflections
416 parameters
H-atom parameters constrained
Δρ_max = 3.26 e Å⁻³
Δρ_min = −2.53 e Å⁻³

Data collection: PROCESS-AUTO (Rigaku Corporation, 1998 ▶); cell refinement: PROCESS-AUTO; data reduction: CrystalStructure (Rigaku Americas & Rigaku Corporation, 2008 ▶); program(s) used to solve structure: SIR2002 (Burla et al., 2003 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: CrystalMaker (Palmer, 2009 ▶); software used to prepare material for publication: publCIF (Westrip, 2009 ▶).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S160053680903712X/zq2004sup1.cif

e-65-m1323-sup1.cif^{(41.3KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S160053680903712X/zq2004Isup2.hkl

e-65-m1323-Isup2.hkl^{(492.7KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Selected geometric parameters (Å, °).

Pb1—Br3	2.8786 (8)
Pb1—Br4	2.9927 (7)
Pb1—Br1	2.9957 (7)
Pb1—Br6	3.0080 (7)
Pb1—Br5	3.0095 (7)
Pb1—Br2	3.1965 (8)
Pb2—Br8	2.8755 (8)
Pb2—Br5ⁱ	2.9935 (6)
Pb2—Br6	2.9957 (7)
Pb2—Br1ⁱⁱ	3.0082 (7)
Pb2—Br4ⁱⁱⁱ	3.0110 (7)
Pb2—Br7	3.1982 (8)

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) .

Table 2. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1⋯Br1	0.89	3.18	3.508 (5)	104
N1—H3⋯Br2	0.89	2.54	3.411 (5)	165
N2—H13⋯Br6	0.89	3.17	3.509 (5)	105
N2—H14⋯Br7	0.89	2.54	3.416 (5)	167
N3—H26⋯Br7	0.89	2.71	3.448 (6)	142
N3—H27⋯Br2	0.89	2.62	3.486 (6)	164
N4—H37⋯Br4	0.89	2.68	3.465 (5)	148
N4—H39⋯Br2	0.89	2.73	3.462 (6)	140

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Acknowledgments

This study was supported financially by CREST from the Japan Science and Technology Agency. The authors thank Professor H. Adachi of Osaka University and Sosho Inc. for careful advice on the refinement. We thank Dr Y. Takeoka of Sophia University for helpful advice on the synthesis.

supplementary crystallographic information

Comment

Recently, much attention has been paid to low-dimensional materials that often exhibit characteristic electronic properties considerably different from those of bulk ones. However, their crystallographic studies are limited because their anisotropic growth nature makes it difficult to obtain a good single crystal. Mitzi reported the structure of the tetrachloroplumbate, (C₆H₅C₂H₄NH₃)₂PbCl₄, whose single crystals required approximately one year to be grown up. The present paper is the first report of the detailed structure of the tetrabromoplumbate, whose single crystals were grown up in approximately two months; in order to compare with some related materials: see the tetrachloroplumbate, the tetrabromozincate, (C₆H₅C₂H₄NH₃)₂ZnBr₄ (Huh et al., 2006), and the tribromoplumbate, (C₆H₅C₂H₄NH₃)PbBr₃ (Billing & Lemmerer, 2003).

Fig. 1 shows the packing diagram of (C₆H₅C₂H₄NH₃)₂PbBr₄, viewed approximately along the c axis. The sheets of corner-sharing PbBr₆ octahedra are separated by bilayers of phenethylammonium cations. The corner-sharing PbBr₆ octahedra are the common structure among bis-(phenethylammonium) tetrahaloplumbates, (C₆H₅C₂H₄NH₃)₂PbX₄ (X = Cl, Br, and I), regardless of the halogen, but are different from face-sharing PbBr₆ octahedra of the tribromoplumbate, (C₆H₅C₂H₄NH₃)PbBr₃, and from isolated tetrahedral ZnBr₄ of the tetrabromozincate, (C₆H₅C₂H₄NH₃)₂ZnBr₄. As the structure of halometalate is notably controlled by surrounding organic molecules, hydrogen bondings between them are discussed later.

Dashed line in Fig. 1 displays the triclinic unit cell, which is similar to the triclinic unit cell of the tetrachloroplumbate, (C₆H₅C₂H₄NH₃)₂PbCl₄, but different from the monoclinic unit cell of the tetraiodoplumbate, (C₆H₅C₂H₄NH₃)₂PbI₄. The present tetrabromoplumbate possesses two independent but similar Pb atoms with distorted octahedral coordination. The Pb—Br bond lengths range from 2.8755 (8) to 3.1982 (8) Å (average: 3.0136 (7) Å) and Br—Pb—Br bond angles range from 83.44 (2)° to 96.67 (2)° and from 170.97 (2)° to 179.36 (2)°. These angles are somewhat different from those of the perfect octahedron, i.e., 90.0° and 180°, respectively. Furthermore, the bridging Pb—Br—Pb bond angles significantly differ from 180° and range from 150.77 (3)° to 152.15 (3)°. This indicates that adjacent PbBr₆ are rotated relative to each other.

Fig. 2 shows the relative rotation of PbBr₆ in the sheet and the hydrogen bondings between the octahedra and ammonium groups. Each ammonium group interacts with three halogen anions through N—H···Br hydrogen bonding in "terminal halogen configuration" involving two terminal halogen anions and one bridging halogen anion (Chapuis et al., 1976). The average hydrogen-bonding distance is 2.630 (2) Å, which is considerably shorter than the sum of the van der Waals radii for H (1.20–1.45 Å) and Br (1.95 Å) (Bondi, 1964). As a result, the opposite sides of the quadrangle, defined by one set of four PbBr₆ octahedra, are "pinched-in" or "pushed-out" as shown in Fig. 2. In addition, there are four independent phenethylammonium depicted as PE1, PE2, PE3, and PE4, having similar bond lengths and bond angles. Therefore, two sides of the unit cell along with a and b axes are about twice length of a PbBr₆ to have a superstructure in it.

There is no significant π-π interaction found in the organic bilayers because the adjacent aromatic rings are considerably separated by centroid-to-centroid distance of 5.748 (9) Å between PE1 and PE4, and 5.787 (9) Å between PE2 and PE3, respectively. The van der Waals radius for aromatic carbon atoms is about 1.77 Å (Bondi, 1964).

Experimental

Single crystals were obtained in the following three steps. First, phenethylamine bromide, C₆H₅C₂H₂NH₃Br, as the precursor was synthesized at 10 C° from stoichiometric amount of hydrobromic acid, HBr, and phenethylamine, C₆H₅C₂H₂NH₂, by their acid-base reaction in a flask. After evaporating the solvent, water, at 70 C°, the white deposition was washed by diethyl ether to remove unreacted reagents and dried in vacuum. Second, the objective compound was synthesized at 25 C° in dry nitrogen atmosphere from stoichiometric amount of the precursor and lead bromide (II), PbBr₂, using dehydrated N,N'-dimethylformamide (DMF) as a good solvent. The purity of PbBr₂ powder was 4 N, and it was used as delivered from Kojundo Chemical Laboratory Co., Japan. Third, the solution was filtered and contained in a glass bottle for the crystal growth. The bottle was contained in a shaded desiccator where another bottle with nitromethane as a poor solvent was also contained. Then, the vapor of the poor solvent was gradually diffused into the solution to reduce the solubility. Settling it two months grew colorless transparent crystals at the bottom of the former bottle. The crystal size was typically 8 mm × 6 mm × 1 mm, and the one used for the crystallographic study was 0.25 mm × 0.20 mm × 0.03 mm.