Triptycene End-Capped Quinoxalinophenanthrophenazines with Aromatic Substituents – Synthesis, Characterization, and Single-Crystal Structure Analysis

Abstract

In a previous study, we found that one-fold triptycene endcapped quinoxalinophenanthrophenazines (QPPs) arrange in crystals preferably in a coplanar fashion providing high overlap of the π-planes. Thus, resulting in high calculated charge transfer integrals. Most interestingly, this motif was observed for a variety of QPPs derivatives, independently of the nature of their peripheral substituents, e.g. bromide, methoxy, cyano, or triisopropylsilylethynyl groups, and of the crystallization conditions. Here, we describe the synthesis of another small series of three QPPs containing different aromatic substituents at the same position to get an insight, whether these aromatic substituents disturb the otherwise preferred π stacking of the QPP planes. d Intensity ratio between the first and second emission peak.A solution of diamine 1b (14.0 mg, 36.5 µmol) and diketone 2 23 (15.2 mg, 24.4 µmol) in chloroform (1.4 mL) and glacial acetic acid (0.07 mL) was stirred at 70°C under an

Triptycene End‐Capped Benzothienobenzothiophene and Naphthothienobenzothiophene

“…By single‐crystal X‐ray diffraction five single‐crystal structures of T‐BTBT were obtained, two of them by sublimation methods. Antiparallel π dimers, comparable to those found for the previously published QPPs, were found in four of those structures. This once more illustrates the scope of the triptycene end‐capping as a crystallographic synthon for enhanced cofacial π stacking.…”

“…As already mentioned in the introduction, we were interested in how the triptycenylene unit affects the packing in the crystalline state and if it has a similar effect than prior observed for the QPP systems . T‐BTBT showed a high crystallization tendency and five different crystal structures were obtained.…”

Synthesis and Optoelectronic Properties of a Quinoxalino‐Phenanthrophenazine (QPP) Extended Tribenzotriquinacene (TBTQ)

“…Single crystals suitable for X‐ray diffraction of QPP 18 could be grown by vapor diffusion of MeOH in solutions of 18 in either CHCl 3 (solvate α), toluene (solvate β) or by slowly cooling a hot saturated solution in mesitylene (solvate γ ). In the α and β solvate the QPP molecules form antiparallel π stacked dimers with d π = 3.38–3.52 Å (Figure 2 a, b), which is frequently found for triptycene end‐capped compounds [21r,s, 33] . Adjacent dimers arrange in an edge‐to‐face orientation in a herringbone‐type motif and interact via van der Waals forces (Figure 2 c).…”

“…In the γ structure, mesitylene is π stacked onto the QPP plane (Figure 2 e), forming one‐dimensional mixed stacked columns along the crystallographic c axis (Figure 2 f). Noteworthy, out of 24 structures of triptycene end‐capped QPPs, [21r,s] this is the only structure, in which no antiparallel π dimers are found (For a detailed crystallographic discussion, see the Supporting Information).…”

Triptycene End‐Capping as Strategy in Materials Chemistry to Control Crystal Packing and Increase Solubility

“…Subsequently, we tested the reliability of the directing effect under the influence of structural variation and crystallization conditions. For this, QPP derivatives were synthesized, bearing electron‐donating (−OMe) or withdrawing (−CN) substituents, a halide (−Br) [31] or aromatic substituents, [32] which may compete with the π stacking motif by additional interactions, such as hydrogen or halogen bonding, dipol‐dipol interactions and π stacking (Figure 5). However, the relative alignment of the dimers and the offset of the π planes was depending on the crystallization conditions.…”