Halogen‐Bonded Assemblies of Arylene Imides and Diimides: Insight from Electronic, Structural, and Computational Studies

Abstract

Halogen‐bonding interactions in electron‐deficient π scaffolds have largely been underexplored. Herein, the halogen‐bonding properties of arylene imide/diimide‐based electron‐deficient scaffolds were studied. The influence of scaffold size, from small (phthalimide) to moderately sized (pyromellitic diimide or naphthalenediimides) to large (perylenediimide), axial‐group modification, and number of halo substituents on the halogen bonding and its self‐assembly was probed in a set of nine compounds. The structural modification leads to tunable optical and redox properties. The first reduction potential E1/21 ranges between −1.09 and −0.17 V (vs. SCE). Two of the compounds, that is, 6 and 9, have deep‐lying LUMOs with values reaching −4.2 eV. Single crystals of all nine systems were obtained, which showed Br⋅⋅⋅O, Br⋅⋅⋅Br, or Br⋅⋅⋅π halogen‐bonding interactions, and a few systems are capable of forming all three types. These interactions lead to halogen‐bonded rings (up to 12‐membered), which propagate to form stacked 1D, 2D, or corrugated sheets. A few outliers were also identified, for example, molecules that prefer C−H⋅⋅⋅O hydrogen bonding over halogen bonding, or noncentrosymmetric rather than centrosymmetric organization. Computational studies based on Atoms in Molecules and Natural Bond Orbital analysis provided further insight into the halogen‐bonding interactions. This study can lead to a predictive design tool‐box to further explore related systems on surfaces reinforced by these weak directional forces.

Synthesis, optical and redox attributes of core-/bay-substituted thionated NDIs, PDIs and their diverse radical anions

“…14 Thus, the persistent search for new electron-deficient π-scaffolds continues. 15–25 A notable recent example is the synthesis of electron-deficient anthracene diimides. 16 a , b To further expand the repertoire of radical anions, synthetic tailorability at the imide O atoms as well as the core- and bay-/non-bay-positions in NDIs and PDIs, respectively, can be performed to access a large number of molecules with moderate to strong π-acidic surfaces suitable for electron injection and generation of long-lived radical anions.…”

Halogen Bond‐Involving Supramolecular Assembly Utilizing Carbon as a Nucleophilic Partner of I⋅⋅⋅C Non‐covalent Interaction

“…[66] Isocyanide 2 was synthesized from commercial durene accordingly to the four-step procedure detailed in the Supporting Information. [67][68] NMR spectra were recorded on Bruker AVANCE III 400 spectrometers in CDCl 3 at ambient temperature (at 400 and 100 MHz for 1 H and 13 XRD studies: XRD experiments were performed using Xcalibur, Eos (1 • 1,4-FIB and 1 • TIE) and XtaLAB Sinergy, Single source at home/ near, HyPix (1 • 4,4'-FIBP and 2 • 1,4-FIB) diffractometers. All crystals were kept at 100 K during data collection.…”

“…[10] Although a number of reports focused on (or related to) HaB demonstrates an impressive growth, some little-studied areas still remain open for further studies. In particular, among the nucleophilic centers that form HaBs, non-metal atoms bearing electron lone pair(s) (abbreviated as LP(s)) such as N, O, a halogen, [8,[11][12][13][14] and π-systems (combining several atoms), [13,[15][16][17] and even metal-donating metal sites [18] are most often applied to provide a HaB-involving pairing. However, the reported HaBs with a carbon atom's lone pair, functioning as a HaB acceptor, are very rare and such C-based σ-hole acceptors in the condensed phases are known only for carbene and isocyanide species.…”

Recent Developments in Polymeric Assemblies and Functional Materials by Halogen Bonding

“…very low reduction potentials, red‐shifted optical features, stable radical anions and enhanced semiconducting properties compared to bis‐ and tetrabromo analogues. Furthermore, they extended their research by studying the effect of halogen bonding on a series of halo‐subtituted electron‐deficient π‐systems with varying scaffold sizes (phthalimide, pyromellitic diimide, naphthalenediimides or perylenediimide) for tuning their optical and electronic properties [117] . The self‐assembled systems were stabilized via Br⋅⋅⋅O, Br⋅⋅⋅Br, or Br⋅⋅⋅π halogen bonding, with some of them possessing all of these interactions simultaneously.…”