Molecular and crystal properties of E-1,2-bis(3-methoxy-2-thienyl)ethene: static disorder in the crystal

Abstract

The crystal structure of E-1,2-bis(3-methoxy-2-thienyl)ethene (C12H12O2S2) has been determined at five different temperatures, i.e. room temperature (293), 223, 173, 123 and 93 K. The solid-state work is complemented by the results of theoretical calculations of energies, geometries, difference electron densities and atomic charges of the free molecule. Analysis revealed static disorder caused by a higher energy conformer of the title compound, probably contaminating the crystal during its growth. The results support the contention that the electrical properties are mainly governed by the carbon backbone.

Combining Electron-Neutral Building Blocks with Intramolecular “Conformational Locks” Affords Stable, High-Mobility P- and N-Channel Polymer Semiconductors

“…The rigorous planarity of M1 is evident in the crystal structure (Figure 1A), which contains cocrystallized, ∼97% of the low-energy sp,sp conformer and ∼3% of a higher-energy ap,ap conformer, similar to the situation in TVT crystals. 50,51 DFT computation shows that the sp,sp conformer is ∼1.15 kcal/mol lower in energy than the ap,ap conformer (Figures 1 and Supporting 1nformation). Importantly, the intramolecular 45,52 M1 crystallizes in a typical herringbone packing motif with a π−π packing distance between neighboring molecules of 5.137 Å (Figure S1, Supporting 1nformation) and with no intermolecular O•••S bonding.…”

Annulated Thienyl-Vinylene-Thienyl Building Blocks for π-Conjugated Copolymers: Ring Dimensions and Isomeric Structure Effects on π-Conjugation Length and Charge Transport

“…Figure 2 shows the single crystal X-ray structures of three ATVT building blocks (1−3) as well as that of TVT. 72− 75 The TVT units annulated with five-carbon atoms (1 and 2) have planar structures (Figure 2b,c), a characteristic not observed in conventional 3,3′-alkyl-substituted bithiophene and TVT derivatives. 29,55,56,76,77 In contrast, building block 3 is significantly distorted (Figure 2d), owing to the larger sixmembered rings and the tendency to achieve an armchair conformation.…”

“…The vinylene length (−CHCH−) of each ATVT increases in the order: 4.22 Å ( 1 ) < 4.27 Å ( 2 ) < 4.28 Å ( 3 ). The vinylene length of 1 is even shorter than in TVT (4.23 Å), − indicating the effective π-conjugation of 1 . In contrast, the distorted structure of 3 should decrease the electronic coupling in the corresponding π-conjugated small molecules and polymers …”

“…Figure shows the single crystal X-ray structures of three ATVT building blocks ( 1 – 3 ) as well as that of TVT . − The TVT units annulated with five-carbon atoms ( 1 and 2 ) have planar structures (Figure b,c), a characteristic not observed in conventional 3,3′-alkyl-substituted bithiophene and TVT derivatives. ,,,, In contrast, building block 3 is significantly distorted (Figure d), owing to the larger six-membered rings and the tendency to achieve an armchair conformation . The six-membered ring annulation also results in an asymmetric structure of the thiophene rings of 3 (C2–C3, 1.371(11) Å; C4–C1, 1.328(12) Å), while the five-membered ring annulation gives more symmetric structures of 1 (C2–C3, 1.369(3) Å; C4–C1, 1.363(3) Å) and 2 (C2–C3, 1.370(6) Å; C4–C1, 1.355(6) Å).…”