Polymorphism and pseudosymmetry of 10,10'-oxybis(9-thia-10-hydro-10-boraanthracene).

Michael Bolte,Julian Radtke,Hans-Wolfram Lerner

doi:10.1107/s205698901900522x

Abstract

We have encountered two polymorphs of the title compound, C24H16B2OS2, both of which display almost the same unit-cell parameters. Compound (I) crystallizes in the non-centrosymmetric space group P21 with four mol-ecules in the asymmetric unit. These mol-ecules are related by pseudosymmetry. As a result, the space group looks like P21/c, but the structure cannot be refined successfully in that space group. Compound (II) on the other hand crystallizes in the centrosymmetric space group P21/c with only two mol-ecules in the asymmetric unit. The crystals studied for (I) and (II) were both non-merohedral twins.

Highlights

We have encountered two polymorphs of the title compound, C24H16B2OS2, both of which display almost the same unit-cell parameters
Compound (II) on the other hand crystallizes in the centrosymmetric space group P21/c with only two molecules in the asymmetric unit
Extended, conjugated -systems are of great interest for both fundamental as well as applied materials research. They are typically utilized as key components for optoelectronic devices, such as organic field-effect transistors (OFETs), organic light-emitting diodes (OLEDs), and organic photovoltaics (OPVs), or as electrode materials in lithium batteries, often acting as the functional layer within these devices (Wu et al, 2007; Harvey, 1997)

Summary

Chemical context

Extended, conjugated -systems are of great interest for both fundamental as well as applied materials research They are typically utilized as key components for optoelectronic devices, such as organic field-effect transistors (OFETs), organic light-emitting diodes (OLEDs), and organic photovoltaics (OPVs), or as electrode materials in lithium batteries, often acting as the functional layer within these devices (Wu et al, 2007; Harvey, 1997). Archetypal examples from this class of compounds are polycyclic aromatic hydrocarbons (PAHs), which can be considered as well-defined cutouts of graphene with adjustable molecular structure design and predictable supramolecular arrangements (Rieger & Mullen, 2010). The B—O—B angles are significantly widened in both structures [(I): B2A—O1A—B1A 146.0 (6), B1B—O1B— B2B 164.8 (7), B2C—O1C—B1C 166.0 (7), B1D—O1D— B2D 165.9 (7); (II): B2—O1—B1 172.0 (7) B1A—O1A— B2A 159.5 (7)]

Structural commentary

Supramolecular features

Database survey

Synthesis and crystallization

Findings

Refinement