Two-dimensional bricklayer arrangements of tolans using halogen bonding interactions

Abstract

Diphenylacetylene (tolan) derivatives with self-complementary aryl halides and halogen bond-accepting nitriles form 2D bricklayer packing motifs when halogen bonding occurs. When halogen bonding is absent, as occurred with fluorinated aryl bromides, the molecules adopt other packing motifs. These results suggest halogen bonding is potentially useful for producing rarely observed 2D bricklayer motifs in organic semiconductors.

Bridging the Void: Halogen Bonding and Aromatic Interactions to Program Luminescence and Electronic Properties of π-Conjugated Materials in the Solid State

“…In 2015, research from our lab by Frausto explored the tunability of XB strength in terminally substituted tolans, where intermolecular XB between terminal donors and acceptors (nitrile) can form colinear arrangements with bricklayer packing between XB-assembled layers. 56 Shown in Figure 2c, a series of six tolans were prepared with variable XB donor strength, using I or Br donors combined with different levels of fluorination. While a crystal structure of a tetrafluoroiodo-XB donor (1) adopted bricklayer packing with tighter XB distance relative to the nonfluorinated (2) analog (2.97 vs 3.16 Å CN−I distance), structures of tetrafluoro and difluorobrominated tolans (3 and 4) adopted herringbone and slipped packing without any notable interactions of Br atoms, instead revealing close contacts between nitriles and fluoroarenes.…”

Organic electrode materials with solid-state battery technology

“…Even though the herringbone packed materials transport carriers well, according to reports the most favorable packing for achieving the fast transport is the cofacial brick stacking, where each molecule interacts with four other molecules. [95][96][97] In order to stabilize the cofacial brick-type stacking it is important to note that the C-H-p interaction causing the materials to adopt the herringbone stacking is rather strong; and to overcome it, strong edge-edge interactions have to be designed. 97 Steric groups.…”

“…[95][96][97] In order to stabilize the cofacial brick-type stacking it is important to note that the C-H-p interaction causing the materials to adopt the herringbone stacking is rather strong; and to overcome it, strong edge-edge interactions have to be designed. 97 Steric groups. There are several ways to control the packing mode, one of the most successful approaches being the introduction of bulky substituents to the carbon skeleton.…”

“…As a result, the intermolecular distance between the pentacene skeletons decreases considerably (from 6.27 to 3.47Å), leading to conductivity enhancements which may be even six orders of magnitude compared to nonsubstituted pentacene. 97 In practice, however, achieving such drastic improvements requires careful planning and experimentation. For example in the aforementioned pentacene case, it was crucial to selectively attach the TIPS substituent to the middle benzene ring.…”

Synergistic effects of halogen bond and π–π interactions in thiophene-based building blocks

“…Although recognized as a signicant force in improving the packing of many halogen-containing organic compounds, [9][10][11][12] halogen bonding (XB) has been scarcely investigated within "bottom-up" approaches towards organic devices. [13][14][15][16] Halogen bonds, analogues of hydrogen bonds, are non-covalent interactions between Lewis acidic halogen atoms and electron-pairdonating heteroatoms. 17 The phenomenon is explained by the presence of a region of positive electrostatic potential (i.e., shole) on the outermost surface of the halogen atom.…”