The Impact of Aggregation on the Photophysics of Spiro‐Bridged Heterotriangulenes

Abstract

We report on the impact of the central heteroatom on structural, electronic, and spectroscopic properties of a series of spirofluorene‐bridged heterotriangulenes and provide a detailed study on their aggregates. The in‐depth analysis of their molecular structure by NMR spectroscopy and X‐ray crystallography was further complemented by density functional theory calculations. With the aid of extensive photophysical analysis the complex fluorescence spectra were deconvoluted showing contributions from the peripheral fluorenes and the heteroaromatic cores. Beyond the molecular scale, we examined the aggregation behavior of these heterotriangulenes in THF/H2O mixtures and analyzed the aggregates by static and dynamic light scattering. The excited‐state interactions within the aggregates were found to be similar to those found in the solid state. A plethora of morphologies and superstructures were observed by scanning electron microscopy of drop‐casted dispersions.

A Chiral Molecular Cage Comprising Diethynylallenes and N‐Heterotriangulenes for Enantioselective Recognition

“…[31] Regarding the implementation of triarylamines in both macrocyclic and cage structures, few examples can be tracked down in literature, [32][33][34][35][36][37][38][39] and even scarcer examples are found for their bridged analogues, N-HTAs, whose presence in complexing and sensing processes is limited. [40][41][42][43][44][45] Besides exploring uncharted waters, N-HTA are also of interest given their solid candidacy for next-generation optoelectronic materials, [46][47][48] and properties such as reversible redox chemistry. [49] Here we present the synthesis and full characterization of an organic covalent chiral cage composed of enantiopure DEAs and electron-rich dimethylmethylene-bridged N-HTAs together with the evidence for its enantioselective sensing ability in solution.…”

“… [31] Regarding the implementation of triarylamines in both macrocyclic and cage structures, few examples can be tracked down in literature,[ 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 ] and even scarcer examples are found for their bridged analogues, N ‐HTAs, whose presence in complexing and sensing processes is limited. [ 40 , 41 , 42 , 43 , 44 , 45 ] Besides exploring uncharted waters, N ‐HTA are also of interest given their solid candidacy for next‐generation optoelectronic materials,[ 46 , 47 , 48 ] and properties such as reversible redox chemistry. [49] …”

The Excited‐State Creutz–Taube Ion

“…The target is to achieve molecular wire behavior and to implement such molecular materials in molecular electronics. [24][25][26][27][28][29] More than fifty years after the appearance of the CT 5 + ion, research on this field is still very active, [30][31][32][33][34][35][36][37][38][39] but has been primarily focused on ground-state mixed valence (GSMV) systems. This has been favored by the experimental accessibility of IVCT absorptions, on one hand, and ground state redox potentials, which are an additional key feature that allow to characterize electronic communication between the redox sites, [40] on the other hand.…”

The Impact of Aggregation of Quaterthiophenes on the Excited State Dynamics

“…Understanding the essential structure–property correlation and the relaxation dynamics of multichromophoric organic aggregated materials is very important for designing potential materials for organic electronics, sensing devices, photocatalysis, and light-energy conversion devices. − The temperature, solvent effect, concentration, and solubility are the decisive factors for molecular aggregation. − Intermolecular interactions like π–π stacking, hydrogen bonding, hydrophobic or electrostatic interactions, van der Waals forces, etc., alter with the degree of molecules’ aggregation. All of those mentioned above eventually control the photophysical behavior. − Therefore, a systematic study is required to understand the excited state dynamics with varying aggregation degrees, which will benefit artificial light-harvesting systems. − …”