Polymorphism in Oligothiophenes with an Even Number of Thiophene Subunits

Abstract

Polymorphism of oligothiophenes, especially quaterthiophene (4T)—see previous communication—has also been studied by another group. They report the growth of large single crystals of 4T from the vapor phase and their characterization by single‐crystal X‐ray diffraction spectroscopy. The Figure shows the shift between two nearest neighbor molecules in the vapor‐grown polymorph of 4T necessary for close packing.

Confocal Raman Spectroscopy of α‐Sexithiophene: From Bulk Crystals to Field‐Effect Transistors

“…This is in agreement with previous observations that show that this phase, whose density is only slightly larger than that of the HT structure, is the packing most commonly obtained from vapour at low temperature. [29] Deposition at higher temperatures may possibly induce phase mixing that can be conveniently investigated with confocal Raman phonon mapping.…”

Crystal structure of (NH3–R–NH3)(NH3–R–NH2)PbI5 (R=5,5′-bis(ethylsulfanyl)-2,2′-bithiophene): NH3+⋯NH2 interaction as a tool to reach densely packed organic layers in organic-inorganic perovskites

“…Thus, a 1D network of molecules linked via S?S contacts smaller than 3.9 Å is evidenced along b in the title compound. This chosen limit value (3.9 Å ) is higher than twice the van der Waals radius of the sulfur atom, but shorter contacts are however not so common in neutral molecules based oligothiophene compounds [15][16][17]. For example, the shorter S?S intermolecular contact is 4.2 Å in the asexithiophene structure [17], a well-known compound for displaying high field effect mobility in thin film transistor [18].…”

Unbound exciton–phonon states in oligothiophene crystals – A model approach for spectroscopic purposes

“…Oligothiophenes crystallize in the monocyclic system with two or four molecules in the unit cell [5][6][7][8][9][10][11][12]. Accordingly, the lowest singlet state, polarized along the long molecular axis, is split into two or four Davydov components.…”