Limits...
Crystal structures of isotypic poly[bis-(benz-imid-azolium) [tetra-μ-iodido-stannate(II)]] and poly[bis-(5,6-di-fluoro-benzimidazolium) [tetra-μ-iodido-stannate(II)]].

Zimmermann I, Keene TD, Hauser J, Decurtins S, Liu SX - Acta Crystallogr Sect E Struct Rep Online (2014)

Bottom Line: The isostructural title compounds, {(C7H7N2)2[SnI4]} n , (1), and {(C7H5F2N2)2[SnI4]} n , (2), show a layered perovskite-type structure composed of anionic {[SnI4](2-)} n sheets parallel to (100), which are decorated on both sides with templating benzimidazolium or 5,6-di-fluoro-benzimidazolium cations, respectively.This is in contrast to most of the reported structures of related compounds where ammonium cations are involved.The coherence between organic bilayers along [100] is mainly achieved through van der Waals inter-actions.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland.

ABSTRACT
The isostructural title compounds, {(C7H7N2)2[SnI4]} n , (1), and {(C7H5F2N2)2[SnI4]} n , (2), show a layered perovskite-type structure composed of anionic {[SnI4](2-)} n sheets parallel to (100), which are decorated on both sides with templating benzimidazolium or 5,6-di-fluoro-benzimidazolium cations, respectively. These planar organic heterocycles mainly form N-H⋯I hydrogen bonds to the terminal I atoms of the corner-sharing [SnI6] octa-hedra (point group symmetry 2) from the inorganic layer, but not to the bridging ones. This is in contrast to most of the reported structures of related compounds where ammonium cations are involved. Here hydrogen bonding to both types of iodine atoms and thereby a distortion of the inorganic layers to various extents is observed. For (1) and (2), all Sn-I-Sn angles are linear and no out-of-plane distortions of the inorganic layers occur, a fact of relevance in view of the material properties. The arrangement of the aromatic cations is mainly determined through the direction of the N-H⋯I hydrogen bonds. The coherence between organic bilayers along [100] is mainly achieved through van der Waals inter-actions.

No MeSH data available.


Related in: MedlinePlus

View along the a* axis of a double layer of tin iodide and the organic cations of (2). For clarity, the [SnI6] octa­hedra are shown as polyhedra, the atoms of the organic cations are represented as spheres with uniform sizes selected for each atom type.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4257208&req=5

fig6: View along the a* axis of a double layer of tin iodide and the organic cations of (2). For clarity, the [SnI6] octa­hedra are shown as polyhedra, the atoms of the organic cations are represented as spheres with uniform sizes selected for each atom type.

Mentions: Compounds (1) and (2) are isostructural. Their asymmetric units, Figs. 1 ▶ and 2 ▶, consist of an Sn2+ cation situated on a twofold rotation axis (Wyckoff position 4e), three iodine atoms [one in a general position, one on an inversion centre (4a) and one on a twofold rotation axis (4e)] and a benz­imid­azolium or 5,6-di­fluoro­benzimidazolium cation, respectively. The main building blocks of the structure are corner-sharing [SnI6] octa­hedra, which form planar sheets with formula {[SnI4]2−}n which extend parallel to (100). The negative charge of these layers is compensated by the organic cations, which are on both sides of the layer, attached by strong hydrogen-bonding and Coulombic inter­actions (Figs. 3 ▶ and 4 ▶). This structural motif can be regarded as an A–B–A layer system, where A represents the aromatic cation and B the tin iodide layer. The coherence between organic bilayers along [100] is mainly achieved through van der Waals inter­actions. The Sn—I bond lengths for (1) range from 3.0626 (3) Å to 3.1607 (3) Å [(2): 3.0491 (5) Å to 3.1596 (3) Å], with no distinct pattern for bridging compared to terminal iodine atoms (Tables 1 ▶ and 2 ▶). These values are in agreement with those reported previously for related tin iodide perovskite structures, as for example [(C4H9NH3)2[SnI4]], where the bond lengths range from 3.133 Å to 3.16 Å (Mitzi, 1996 ▶). The I—Sn—I angles of the [SnI6] octa­hedra in the title structures deviate slightly from the ideal octa­hedral geometry. With 83.886 (4)° for (1) [(2): 84.077 (6)°], the I2—Sn1—I3 angle has the largest difference. On the other hand, all Sn—I—Sn angles are linear, which leads to the formation of an almost rectangular grid (Fig. 5 ▶). There is no out-of-plane distortion of the inorganic sheet. The arrangement of the aromatic cations is mainly determined through the direction of N—H⋯I hydrogen bonds to the apical iodine atoms (Tables 3 ▶ and 4 ▶; Figs. 3 ▶ and 4 ▶). There is no N—H⋯Ibridging contact smaller than the sum of the respective van der Waals radii (H: 1.2, I: 1.98 Å; Bondi, 1964 ▶). This is in contrast to primary ammonium cations, which form hydrogen bonds to both apical and bridging iodine atoms. The shortest H⋯Ibridging distance is C3—H3⋯I2 with 3.12 Å for (1) [(2): 3.19 Å] close to the sum of van der Waals radii. Adjacent cations within an organic layer show a plane-to-plane distance of 3.786 Å for (1) [(2): 3.730 Å] (Fig. 6 ▶). The shortest contact distances between the organic bilayers for both compounds are close to the sums of the van der Waals radii [C8⋯H6i 2.801 Å in (1) and F8⋯H9ii 2.557 Å in (2); (i):  − x, − + y,  − z; (ii):  − x,  − y, −z]. The larger size of the fluorine atom in comparison to the hydrogen atom is reflected in a larger A–B–A layer spacing of 14.407 Å for (2) compared to 13.950 Å for (1).


Crystal structures of isotypic poly[bis-(benz-imid-azolium) [tetra-μ-iodido-stannate(II)]] and poly[bis-(5,6-di-fluoro-benzimidazolium) [tetra-μ-iodido-stannate(II)]].

Zimmermann I, Keene TD, Hauser J, Decurtins S, Liu SX - Acta Crystallogr Sect E Struct Rep Online (2014)

View along the a* axis of a double layer of tin iodide and the organic cations of (2). For clarity, the [SnI6] octa­hedra are shown as polyhedra, the atoms of the organic cations are represented as spheres with uniform sizes selected for each atom type.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4257208&req=5

fig6: View along the a* axis of a double layer of tin iodide and the organic cations of (2). For clarity, the [SnI6] octa­hedra are shown as polyhedra, the atoms of the organic cations are represented as spheres with uniform sizes selected for each atom type.
Mentions: Compounds (1) and (2) are isostructural. Their asymmetric units, Figs. 1 ▶ and 2 ▶, consist of an Sn2+ cation situated on a twofold rotation axis (Wyckoff position 4e), three iodine atoms [one in a general position, one on an inversion centre (4a) and one on a twofold rotation axis (4e)] and a benz­imid­azolium or 5,6-di­fluoro­benzimidazolium cation, respectively. The main building blocks of the structure are corner-sharing [SnI6] octa­hedra, which form planar sheets with formula {[SnI4]2−}n which extend parallel to (100). The negative charge of these layers is compensated by the organic cations, which are on both sides of the layer, attached by strong hydrogen-bonding and Coulombic inter­actions (Figs. 3 ▶ and 4 ▶). This structural motif can be regarded as an A–B–A layer system, where A represents the aromatic cation and B the tin iodide layer. The coherence between organic bilayers along [100] is mainly achieved through van der Waals inter­actions. The Sn—I bond lengths for (1) range from 3.0626 (3) Å to 3.1607 (3) Å [(2): 3.0491 (5) Å to 3.1596 (3) Å], with no distinct pattern for bridging compared to terminal iodine atoms (Tables 1 ▶ and 2 ▶). These values are in agreement with those reported previously for related tin iodide perovskite structures, as for example [(C4H9NH3)2[SnI4]], where the bond lengths range from 3.133 Å to 3.16 Å (Mitzi, 1996 ▶). The I—Sn—I angles of the [SnI6] octa­hedra in the title structures deviate slightly from the ideal octa­hedral geometry. With 83.886 (4)° for (1) [(2): 84.077 (6)°], the I2—Sn1—I3 angle has the largest difference. On the other hand, all Sn—I—Sn angles are linear, which leads to the formation of an almost rectangular grid (Fig. 5 ▶). There is no out-of-plane distortion of the inorganic sheet. The arrangement of the aromatic cations is mainly determined through the direction of N—H⋯I hydrogen bonds to the apical iodine atoms (Tables 3 ▶ and 4 ▶; Figs. 3 ▶ and 4 ▶). There is no N—H⋯Ibridging contact smaller than the sum of the respective van der Waals radii (H: 1.2, I: 1.98 Å; Bondi, 1964 ▶). This is in contrast to primary ammonium cations, which form hydrogen bonds to both apical and bridging iodine atoms. The shortest H⋯Ibridging distance is C3—H3⋯I2 with 3.12 Å for (1) [(2): 3.19 Å] close to the sum of van der Waals radii. Adjacent cations within an organic layer show a plane-to-plane distance of 3.786 Å for (1) [(2): 3.730 Å] (Fig. 6 ▶). The shortest contact distances between the organic bilayers for both compounds are close to the sums of the van der Waals radii [C8⋯H6i 2.801 Å in (1) and F8⋯H9ii 2.557 Å in (2); (i):  − x, − + y,  − z; (ii):  − x,  − y, −z]. The larger size of the fluorine atom in comparison to the hydrogen atom is reflected in a larger A–B–A layer spacing of 14.407 Å for (2) compared to 13.950 Å for (1).

Bottom Line: The isostructural title compounds, {(C7H7N2)2[SnI4]} n , (1), and {(C7H5F2N2)2[SnI4]} n , (2), show a layered perovskite-type structure composed of anionic {[SnI4](2-)} n sheets parallel to (100), which are decorated on both sides with templating benzimidazolium or 5,6-di-fluoro-benzimidazolium cations, respectively.This is in contrast to most of the reported structures of related compounds where ammonium cations are involved.The coherence between organic bilayers along [100] is mainly achieved through van der Waals inter-actions.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland.

ABSTRACT
The isostructural title compounds, {(C7H7N2)2[SnI4]} n , (1), and {(C7H5F2N2)2[SnI4]} n , (2), show a layered perovskite-type structure composed of anionic {[SnI4](2-)} n sheets parallel to (100), which are decorated on both sides with templating benzimidazolium or 5,6-di-fluoro-benzimidazolium cations, respectively. These planar organic heterocycles mainly form N-H⋯I hydrogen bonds to the terminal I atoms of the corner-sharing [SnI6] octa-hedra (point group symmetry 2) from the inorganic layer, but not to the bridging ones. This is in contrast to most of the reported structures of related compounds where ammonium cations are involved. Here hydrogen bonding to both types of iodine atoms and thereby a distortion of the inorganic layers to various extents is observed. For (1) and (2), all Sn-I-Sn angles are linear and no out-of-plane distortions of the inorganic layers occur, a fact of relevance in view of the material properties. The arrangement of the aromatic cations is mainly determined through the direction of the N-H⋯I hydrogen bonds. The coherence between organic bilayers along [100] is mainly achieved through van der Waals inter-actions.

No MeSH data available.


Related in: MedlinePlus