Sugiyama H, Uekusa H. Two-step crystal-crystal phase transformation of N-salicylidene-p-aminobenzoic acid by gas-solid reaction with aqua-ammonia vapour.
ACTA CRYSTALLOGRAPHICA SECTION C-STRUCTURAL CHEMISTRY 2021;
77:56-60. [PMID:
33397825 DOI:
10.1107/s2053229620016411]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 12/18/2020] [Indexed: 11/10/2022]
Abstract
Crystal-crystal phase transformation by external stimuli has attracted significant attention for application in switchable materials, which can change their structures and properties. Herein, it is revealed that N-salicylidene-p-aminobenzoic acid crystals undergo a two-step crystal-crystal phase transformation through a gas-solid reaction with aqua-ammonia vapour. The photochromic behaviour of the crystals switched from nonphotochromic to photochromic and back to nonphotochromic via a phase transformation. The two-step phase transformation and photochromic behaviour change were characterized and correlated by X-ray crystal structure analysis, UV-Vis spectroscopy, differential scanning calorimetry and scanning electron microscopy. This article is the first report to capture the stepwise structural change in the gas-solid (acid-base) reaction of ammonia with benzoic acid derivatives.
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