# Self‐assembled Helical Tetramer Stack of Terrylene Bisimide in Solution and Crystalline State

## TL;DR

A TBI derivative self-assembles into helical tetramers in solution and forms complex structures with guest molecules.

## Contribution

The study reveals helical tetramer stacks of TBI and their interaction with aromatic guest molecules in both solution and crystalline states.

## Key findings

- TBI forms helical tetramers via π–π interactions with a strength of ΔG = −40.1 kJ mol−1.
- Addition of perylene leads to hexalayer stacks, while coronene forms 1:2 trilayer complexes.
- X-ray analysis confirms the stacking arrangements in crystalline states.

## Abstract

A terrylene bisimide (TBI) derivative 1 bearing bulky meta‐terphenyl imide substituents is shown to self‐assemble into helical [14] tetramer stacks in solution. Driven by strong dispersion and electrostatic forces, a direct transition from monomers into defined tetramers is already observed in the micromolar concentration range (∼10−6 M) in methylcyclohexane at room temperature, corresponding to a π–π‐interaction strength of ΔG = −40.1 kJ mol−1 for the respective π–π‐stacking interaction between two neighboring TBIs. Upon addition of perylene (P), a further growth of the stacks toward [P.14
.P] hexalayers is observed where the guest molecules are stacked at the peripheral positions. In contrast, upon addition of the larger coronene (C), the equilibrium shifts toward 1:2 complexes [C.1.C] where each TBI is surrounded by two coronene neighbors. Single crystal X‐ray analyses of the pristine [14] tetramer stack as well as the [P.14
.P] hexalayer stack and the 1:2 trilayer [C.1.C] unambiguously confirm the unique stacking arrangements.

A TBI with sterically demanding imide substituents self‐assembles in solution into a defined helical tetramer π‐stack. Both the monomer and the tetramer can form complexes with polycyclic aromatic guest molecules, resulting in the formation of tri‐ or hexalayer in solution and in the crystalline solid state.