Control of Relative Positions of Electron-Donor and Electron-Acceptor Molecules in Charge-Transfer Complexes for Luminescent Property Modulation

Charge-transfer complexes can exhibit various physical properties that depend on the relative positions of electron-donor and electron-acceptor molecules. Several studies have investigated the relationship between the relative positions of electron-donor and electron-acceptor molecules and their luminescence properties. However, elucidating the correlation between the relative positions and detailed luminescence processes without changing the molecular structures has not been explored. Herein, we report control of the relative position based on charge-assisted hydrogen bonds between sulfo and amino groups and on alkylamines' steric factors, and report concomitant modulation of the luminescent properties. Six charge-transfer complexes were prepared from anthracene-2,6-disulfonic acid and 1,2,4,5-tetracyanobenzene as electron-donor and electron-acceptor molecules, and various alkylamines. Different alkylamines' steric factors drastically and precisely changed the relative positions of the electron-donor and electron-acceptor molecules without changing their molecular structures. Consequently, the six crystals exhibited maximum emission wavelengths from 543 to 624 nm and different luminescence processes.

Substituent-Modulated Assembly Formation: An Approach to Enhancing the Photostability of Photoelectric-Sensitive Chalcogenide-Based Ion-Pair Hybrids

A series of electronically active viologen dications (RV) with tunable substituent groups were utilized to hybridize with [Ge₄S₁₀]^4- (T2 cluster) to form the hybrids of T2@RV. These hybrids exhibited variable supermolecular assembly formation, tunable optical absorption properties, and different photoelectric response under the influence of different RV dications. Raman testing and time-dependent photocurrent response indicated that the photosensitivity and photostability of T2@RV could be integrated while choosing suitable RV dications. Current research provides a general method to build a tunable hybrid system based on crystalline metal chalcogenide compounds through the replacement of photoinactive cationic organic templates with photoactive ones with different substituent groups.

Aryl-fused tetrathianaphthalene (TTN): synthesis, structures, properties, and cocrystals with fullerenes

A library of aryl-fused TTN has been synthesized to show shape complementary with fullerene molecules and form “TTN·fullerene” cocrystals.