Engineering of Acentric Stilbazolium Salts with Large Second-Order Optical Nonlinearity and Enhanced Environmental Stability

Abstract

A series of organic nonlinear optical (NLO) materials based on the stilbazolium derivatives of 4-N,N-dimethylamino-4′-N′-methyl-stilbazolium tosylate (DAST) were synthesized, and the single crystals were grown from the solutions. Single-crystal structure determinations and Kurtz powder tests reveal that replacement of the p-toluenesulfonate anion in the DAST crystal, forming 4-N,N-dimethylamino-4′-N′-methyl-stilbazolium 4-aminotoluene-3-sulfonate (1) and 4-N,N-dimethylamino-4′-N′-methyl-stilbazolium p-chlorobenzenesulfonate (2), constructs new acentric crystals with quite a large powder second-harmonic generation (SHG) of more than 3 orders of magnitude larger than that of urea around 2.0 μm, whereas the other two complexes show their centrosymmetric structures without any SHG effects. A possible estimation of the molecular first hyperpolarizabilities β ijk performed on 2 further confirms its origin of its enhanced NLO merits. Furthermore, both 1 and 2 exhibit even higher environmental stabilities, including the antiwater performance and the formation of anhydrous phases in water-containing solutions. We believe that the findings of the further counterion modification will bring new stilbazolium derivatives with improved optical nonlinearities and the physicochemical performances.

High-power Broadband Organic THz Generator

“…In addition, the formation of centrosymmetric hydrate phase is one of the most serious issues. For example, a stilbazolium DAST crystal can be dissolved in water and form a centrosymmetric hydrated phase when it is grown from water-contaminated solvents 45 46 . When HMQ-TMS crystals grown in water solvent mixture (water/methanol = 1:9 v/v), their thermodiagrams obtained from DSC and powder X-ray diffraction patterns are practically identical as the ones for HMQ-TMS crystals grown in methanol only (see SI ).…”

Conformational polymorphism on styrl quinolinium salts of 2-[(E)-2-(4-hydroxy-3-methoxystyrl)-1-methyl]-quinolinium 4-chlorobenzenesulfonate (HMQ-CBS): Potential nonlinear optical crystals for terahertz application

“…An appropriate filter was settled for eliminating the contributions of the potential third-harmonic generation (λ = 683 nm). [17,18] The oscilloscope photoelectric signals reveal that phase-I has SHG efficiency of about ~0.5 times that of DAST (Figure 3), approximately equal to 500 times that of urea. Such an observation discloses that crystals in phase-I may be a potential NLO candidate for THz application.…”

A supramolecular approach towards the construction of molecular salts using phosphonic acid and pyrazole

“…S11, ESI †]. Moreover, the comprehensive H-bonding interactions in the 2D sheets acquired parallel packing in the solid, which further helped in achieving a noncentrosymmetric arrangement 23 in an ABAB pattern.…”