Comments on recently published papers reporting on the growth of bulk crystals based on aromatic amines or optically active forms of ascorbic acid

Abstract

In this study, we comment on recently published papers in the Journal of Materials Science: Materials in Electronics, reporting on the growth of bulk crystals. Prolonged exposure to air during the slow evaporation solution growth process of the following aromatic amine based crystals viz. "p-aminoazobenzene" (also known as aniline yellow) (1) [J Mater Sci: Mater Electron 32 20698-20709 (2021)], "4-aminopyridine-1-ium 4-aminobenzoate" (2) [ibid 32 22342-22361 (2021)], "N-benzyl-3-nitroaniline" (3) [ibid 32 26318-26328 (2021); 34 1895 (2023)], "bis(4-acetylanilinium) tetrachloridozincate" (4) [ibid 32 11,393-11,417 (2021)], "sodium sulfanilate dihydrate" (5) [ibid 30 2224-2234 (2019)], "(E)-N'-[4-(dimethylamino) benzylidene]-4-hydroxybenzohydrazide hemihydrate" (6) [ibid 30 2638-2646 (2019)], "anilinium perchlorate" (7) [ibid 29 5718-5725 (2018)] and "p-toluidinium perchlorate" (8) [ibid 35 1586 (2024)] results in their surface deterioration. The yellow "lithium d-isoascorbate monohydrate" (9), "potassium l-ascorbate monohydrate" (9a) [J Mater Sci: Mater Electron 34 825 (2023); ibid 35 1585 (2024)], yellow "l-ascorbic acid" (10) [ibid 32 8174-8182 (2021); ibid 34 143 (2023)] are examples of surface degraded crystals based on ascorbic acid. Optical properties of surface degraded materials are unreliable. Use of freshly prepared starting reagents and an oxygen-free atmosphere are essential requirements for the growth of bulk crystals of air-sensitive materials, in pure form.