Effect of EDTA on Growth of 4-Dimethylamino-N-Methyl-4-Stilbazolium Tosylate Crystals by Slope Nucleation Method

Abstract

Nucleation experiments (metastable zone width) were carried out for 4-dimethylamino-N-methyl-4-stilbazolium tosylate (DAST) solutions at different saturation temperatures with and without the addition of a chelating agent. Using the results obtained from metastable zone width experiments, the slope nucleation method growth of DAST was performed. It was revealed that the addition of the chelating agent EDTA significantly suppresses spurious nucleation and cluster formation in the DAST solution, so that fewer, but larger, crystals can be easily obtained. With EDTA, the crystals grown also showed better crystallinity, hardness, and transparency in the visible/near-infrared region.

An investigation on the growth and characterization of DAST crystals grown by two zone growth technique

“…As discussed by Mori et al [12], the homogeneity of molecular orientation mainly depends on the growth rate. The measured FWHM of the crystal was 576 arcsec, which was comparable to the FWHM (475 arcsec) of the DAST crystals grown without EDTA reported earlier [17]. However, the grown crystals in the previous reports were much smaller and were grown by a different method, by which it is not easy to get a large crystal.…”

“…From the UV-VIS-NIR spectrum, it was found that the DAST crystal had about 70% of transmission. The transmission edge was observed at about 700 nm, which was 100 nm right shift with the previous report [17]. The change in the transmission edge is due to the orientation of the cationic chromophore in the DAST crystal lattice with respect to its dielectric axes.…”

Surface defects and mechanical hardness of rapidly grown DAST crystals

“…DAST was synthesized by the condensation of 4-methyl-N-methyl pyridinium tosylate and 4-N, N-dimethylaminobenzaldehyde in the presence of piperidine [10,11]. The resulting DAST material was further purified by recrystallization from methanol.…”

Effect of sodium toluene sulfonate on the nucleation, growth and characterization of DAST single crystals

“…DAST was synthesized by the condensation of 4-methyl-N-methyl pyridinium tosylate and 4-N,N-dimethylaminobenzaldehyde in the presence of piperidine [12][13][14]. The 4-methyl-N-methyl pyridinium tosylate used in the condensation reaction was prepared from equimolar quantities of 4-picoline and methyl-p-toluene sulphonate.…”