Two-step crystal–crystal phase transformation of N-salicyl­idene-p-amino­benzoic acid by gas–solid reaction with aqua–ammonia vapour

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.

Computing details

Data collection: PROCESS-AUTO (Rigaku, 1998); cell refinement: PROCESS-AUTO (Rigaku, 1998); data reduction: PROCESS-AUTO (Rigaku, 1998); program(s) used to solve structure: SHELXT2014 (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2018 (Sheldrick, 2015b); molecular graphics: ORTEP-3 (Farrugia, 2012); software used to prepare material for publication: SHELXL2018 (Sheldrick, 2015b).

Azanium 4-{[(2-hydroxyphenyl)methylidene]amino}benzoate

Crystal data

NH4^+·C14H10NO3^−	F(000) = 1088
Mr = 258.27	Dx = 1.371 Mg m^−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71075 Å
a = 43.803 (4) Å	Cell parameters from 7721 reflections
b = 4.6835 (5) Å	θ = 3.3–27.5°
c = 12.2643 (10) Å	µ = 0.10 mm^−1
β = 96.105 (2)°	T = 93 K
V = 2501.8 (4) Å^3	Plate, orange
Z = 8	0.22 × 0.21 × 0.18 mm

Data collection

Rigaku R-AXIS RAPID IP area detector diffractometer	2027 reflections with I > 2σ(I)
Radiation source: rotating anode X-ray tube	Rint = 0.040
ω scans	θmax = 27.5°, θmin = 3.3°
Absorption correction: multi-scan (ABSCOR; Rigaku, 1998)	h = −55→56
Tmin = 0.691, Tmax = 0.983	k = −6→6
12492 measured reflections	l = −14→15
2833 independent reflections

Refinement

Refinement on F^2	Primary atom site location: iterative
Least-squares matrix: full	Hydrogen site location: mixed
R[F^2 > 2σ(F^2)] = 0.057	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.155	w = 1/[σ^2(Fo^2) + (0.0954P)^2 + 0.0572P] where P = (Fo^2 + 2Fc^2)/3
S = 1.08	(Δ/σ)max < 0.001
2833 reflections	Δρmax = 0.45 e Å^−3
188 parameters	Δρmin = −0.33 e Å^−3
21 restraints

Special details

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

Refinement. Data collection scaling and absorption corrections were performed using RAPID-AUTO program. Crystal parameter and refinement details are shown in Table 1. An initial structure was determined by dual space method with SHELXT-2018/2, and refined by full-matrix least-squares on F_o² with SHELXL-2018/3.(Sheldrick, 2015b,a).

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
O1	0.33880 (3)	0.9844 (3)	0.03443 (9)	0.0594 (4)
H1	0.350659	0.872357	0.071872	0.089*
N1	0.36111 (3)	0.6992 (3)	0.20736 (10)	0.0348 (3)
C1	0.31999 (4)	1.1125 (4)	0.09993 (13)	0.0421 (4)
O2	0.46366 (2)	−0.2646 (3)	0.32356 (8)	0.0414 (3)
N2	0.47499 (3)	0.3778 (3)	0.60490 (10)	0.0363 (3)
H2A	0.4959 (3)	0.370 (3)	0.6224 (11)	0.039 (5)*
H2B	0.4692 (3)	0.542 (3)	0.5687 (12)	0.047 (5)*
H2C	0.4684 (4)	0.220 (3)	0.5627 (13)	0.064 (6)*
H2D	0.4656 (3)	0.366 (4)	0.6691 (11)	0.053 (5)*
C2	0.29844 (5)	1.3094 (4)	0.05473 (15)	0.0547 (5)
H2	0.296930	1.350124	−0.021536	0.066*
O3	0.45629 (2)	−0.1223 (2)	0.49153 (8)	0.0401 (3)
C3	0.27932 (4)	1.4450 (4)	0.12011 (17)	0.0558 (5)
H3	0.264726	1.579287	0.088420	0.067*
C4	0.28102 (4)	1.3891 (4)	0.23101 (16)	0.0502 (5)
H4	0.267821	1.485278	0.275530	0.060*
C5	0.30203 (4)	1.1927 (4)	0.27662 (14)	0.0433 (4)
H5	0.303148	1.154023	0.352976	0.052*
C6	0.32176 (3)	1.0490 (3)	0.21266 (12)	0.0346 (4)
C8	0.38202 (3)	0.4944 (3)	0.25718 (11)	0.0311 (3)
C7	0.34333 (3)	0.8413 (3)	0.26321 (12)	0.0348 (4)
H7	0.344285	0.809871	0.340024	0.042*
C9	0.38484 (3)	0.4217 (4)	0.36864 (12)	0.0387 (4)
H9	0.371874	0.509249	0.416275	0.046*
C10	0.40646 (4)	0.2225 (4)	0.40959 (11)	0.0362 (4)
H10	0.408183	0.175282	0.485327	0.043*
C11	0.42570 (3)	0.0903 (3)	0.34178 (11)	0.0298 (3)
C12	0.42230 (3)	0.1584 (3)	0.23080 (11)	0.0340 (4)
H12	0.434880	0.066843	0.182842	0.041*
C13	0.40085 (3)	0.3573 (3)	0.18942 (11)	0.0348 (4)
H13	0.398954	0.401179	0.113368	0.042*
C14	0.45010 (3)	−0.1157 (3)	0.38823 (11)	0.0304 (3)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0726 (9)	0.0676 (10)	0.0380 (6)	0.0255 (7)	0.0054 (6)	0.0070 (6)
N1	0.0386 (7)	0.0298 (7)	0.0349 (6)	0.0029 (5)	−0.0016 (5)	0.0031 (5)
C1	0.0461 (9)	0.0387 (10)	0.0399 (8)	0.0022 (7)	−0.0037 (7)	0.0021 (7)
O2	0.0417 (6)	0.0449 (7)	0.0367 (5)	0.0124 (5)	−0.0003 (5)	−0.0053 (5)
N2	0.0415 (8)	0.0335 (8)	0.0333 (6)	0.0047 (6)	0.0007 (6)	0.0025 (5)
C2	0.0609 (11)	0.0490 (12)	0.0507 (10)	0.0096 (9)	−0.0101 (9)	0.0120 (8)
O3	0.0523 (7)	0.0355 (7)	0.0307 (5)	0.0086 (5)	−0.0041 (5)	0.0019 (4)
C3	0.0455 (10)	0.0415 (11)	0.0763 (13)	0.0112 (8)	−0.0128 (9)	0.0075 (9)
C4	0.0402 (9)	0.0405 (11)	0.0696 (12)	0.0053 (7)	0.0041 (8)	−0.0018 (8)
C5	0.0421 (9)	0.0386 (10)	0.0493 (9)	0.0020 (7)	0.0055 (7)	0.0032 (7)
C6	0.0335 (8)	0.0279 (8)	0.0411 (8)	−0.0020 (6)	−0.0024 (6)	0.0023 (6)
C8	0.0313 (7)	0.0269 (8)	0.0339 (7)	−0.0013 (6)	−0.0012 (5)	0.0018 (5)
C7	0.0378 (8)	0.0320 (9)	0.0339 (7)	−0.0012 (6)	−0.0001 (6)	0.0032 (6)
C9	0.0429 (9)	0.0417 (10)	0.0318 (7)	0.0097 (7)	0.0051 (6)	0.0019 (6)
C10	0.0418 (8)	0.0402 (9)	0.0266 (7)	0.0063 (7)	0.0030 (6)	0.0039 (6)
C11	0.0326 (7)	0.0258 (8)	0.0304 (7)	−0.0021 (6)	0.0000 (5)	0.0008 (5)
C12	0.0386 (8)	0.0327 (9)	0.0308 (7)	0.0025 (6)	0.0043 (6)	0.0006 (6)
C13	0.0433 (8)	0.0342 (9)	0.0266 (7)	0.0013 (7)	0.0015 (6)	0.0042 (6)
C14	0.0341 (7)	0.0257 (8)	0.0309 (7)	−0.0001 (6)	0.0006 (6)	0.0011 (5)

Geometric parameters (Å, º)

O1—H1	0.8400	C4—C5	1.377 (2)
O1—C1	1.351 (2)	C5—H5	0.9500
N1—C8	1.4188 (19)	C5—C6	1.400 (2)
N1—C7	1.2773 (19)	C6—C7	1.449 (2)
C1—C2	1.392 (2)	C8—C9	1.401 (2)
C1—C6	1.408 (2)	C8—C13	1.389 (2)
O2—C14	1.2524 (17)	C7—H7	0.9500
N2—H2A	0.917 (12)	C9—H9	0.9500
N2—H2B	0.912 (12)	C9—C10	1.385 (2)
N2—H2C	0.929 (13)	C10—H10	0.9500
N2—H2D	0.927 (12)	C10—C11	1.3905 (19)
C2—H2	0.9500	C11—C12	1.3904 (19)
C2—C3	1.375 (3)	C11—C14	1.506 (2)
O3—C14	1.2674 (16)	C12—H12	0.9500
C3—H3	0.9500	C12—C13	1.381 (2)
C3—C4	1.379 (3)	C13—H13	0.9500
C4—H4	0.9500
C1—O1—H1	109.5	C5—C6—C7	119.78 (14)
C7—N1—C8	121.57 (12)	C9—C8—N1	124.78 (13)
O1—C1—C2	119.21 (15)	C13—C8—N1	116.88 (12)
O1—C1—C6	121.12 (15)	C13—C8—C9	118.34 (13)
C2—C1—C6	119.68 (15)	N1—C7—C6	121.83 (14)
H2A—N2—H2B	111.7 (12)	N1—C7—H7	119.1
H2A—N2—H2C	110.0 (12)	C6—C7—H7	119.1
H2A—N2—H2D	108.6 (11)	C8—C9—H9	119.9
H2B—N2—H2C	110.2 (12)	C10—C9—C8	120.22 (13)
H2B—N2—H2D	109.6 (12)	C10—C9—H9	119.9
H2C—N2—H2D	106.6 (12)	C9—C10—H10	119.4
C1—C2—H2	119.9	C9—C10—C11	121.16 (12)
C3—C2—C1	120.20 (16)	C11—C10—H10	119.4
C3—C2—H2	119.9	C10—C11—C14	120.64 (12)
C2—C3—H3	119.5	C12—C11—C10	118.34 (13)
C2—C3—C4	121.00 (17)	C12—C11—C14	121.00 (12)
C4—C3—H3	119.5	C11—C12—H12	119.6
C3—C4—H4	120.3	C13—C12—C11	120.82 (13)
C5—C4—C3	119.41 (16)	C13—C12—H12	119.6
C5—C4—H4	120.3	C8—C13—H13	119.5
C4—C5—H5	119.4	C12—C13—C8	121.07 (12)
C4—C5—C6	121.28 (16)	C12—C13—H13	119.5
C6—C5—H5	119.4	O2—C14—O3	123.64 (13)
C1—C6—C7	121.81 (14)	O2—C14—C11	118.85 (12)
C5—C6—C1	118.42 (14)	O3—C14—C11	117.48 (12)
O1—C1—C2—C3	−179.15 (17)	C8—N1—C7—C6	−179.50 (13)
O1—C1—C6—C5	178.82 (16)	C8—C9—C10—C11	−0.1 (2)
O1—C1—C6—C7	−1.1 (3)	C7—N1—C8—C9	1.8 (2)
N1—C8—C9—C10	−178.72 (15)	C7—N1—C8—C13	−178.35 (14)
N1—C8—C13—C12	178.88 (14)	C9—C8—C13—C12	−1.3 (2)
C1—C2—C3—C4	−0.1 (3)	C9—C10—C11—C12	−1.4 (2)
C1—C6—C7—N1	−2.2 (2)	C9—C10—C11—C14	177.15 (14)
C2—C1—C6—C5	−1.5 (2)	C10—C11—C12—C13	1.5 (2)
C2—C1—C6—C7	178.66 (16)	C10—C11—C14—O2	168.74 (14)
C2—C3—C4—C5	−0.5 (3)	C10—C11—C14—O3	−13.1 (2)
C3—C4—C5—C6	0.2 (3)	C11—C12—C13—C8	−0.2 (2)
C4—C5—C6—C1	0.8 (2)	C12—C11—C14—O2	−12.8 (2)
C4—C5—C6—C7	−179.28 (16)	C12—C11—C14—O3	165.32 (14)
C5—C6—C7—N1	177.88 (15)	C13—C8—C9—C10	1.5 (2)
C6—C1—C2—C3	1.1 (3)	C14—C11—C12—C13	−176.96 (14)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1···N1	0.84	1.86	2.6071 (17)	147
N2—H2A···O2^i	0.92 (1)	1.89 (1)	2.7874 (17)	165 (1)
N2—H2B···O3^ii	0.91 (1)	1.89 (1)	2.8007 (17)	179 (2)
N2—H2C···O3	0.93 (1)	1.88 (1)	2.8014 (18)	174 (2)
N2—H2D···O2^iii	0.93 (1)	1.96 (1)	2.8288 (16)	154 (1)

Symmetry codes: (i) −x+1, −y, −z+1; (ii) x, y+1, z; (iii) x, −y, z+1/2.