Hemisynthesis, crystal structure and inhibitory effect of sesquiterpenic thio­semicarbazones and thia­zolidin-4-ones on the corrosion behaviour of stainless steel in 1 M H2SO4 solution

Bimoussa, A.; Koumya, Y.; Abouelfida, A.; Ait Itto, M.Y.; Benyaich, A.; Mentre, O.; Ketatni, E.M.; Auhmani, A.; Auhmani, A.

doi:10.1107/S2053229619005631

Hemisynthesis, crystal structure and inhibitory effect of sesquiterpenic thiosemicarbazones and thiazolidin-4-ones on the corrosion behaviour of stainless steel in 1 M H₂SO₄ solution

A. Bimoussa, Y. Koumya, A. Abouelfida, M. Y. Ait Itto, A. Benyaich, O. Mentre, E. M. Ketatni, A. Auhmani and A. Auhmani

Treatment of thiosemicarbazones prepared from sesquiterpenes with ethyl 2-bromoacetate in the presence of sodium acetate afforded the corresponding thiazolidin-4-ones. The structures of all the newly synthesized compounds were established by considering spectral and single-crystal X-ray diffraction data. The title compound, ethyl 2-((Z)-2-{(Z)-[(1aR,5aR,9aS)-1,1-dichloro-1a,5,5,7-tetramethyl-1a,2,3,4,5,5a,8,9-octahydro-1H-benzo[a]cyclopropa[b][7]annulen-8-ylidene]hydrazono}-4-oxothiazolidin-3-yl)acetate, C₂₃H₃₁Cl₂N₃O₃S, 5, crystallizes in the orthorhombic noncentrosymmetric space group P2₁2₁2₁ with Z = 4. Within the molecule in the crystal structure, the cyclohexene ring has an envelope conformation and the cycloheptane ring, to which it is fused, has a boat conformation. In the crystal, molecules are linked by C—H

Cl hydrogen bonds forming chains propagating along the b-axis direction. The absolute configuration of the molecule in the crystal could be fully confirmed from anomalous dispersion effects [Flack parameter = −0.04 (2)]. Thiosemicarbazones 1 and 2 are efficient inhibitors for steel corrosion in 1 M H₂SO₄ solution, with a maximum efficiency of 92.28% at 10⁻³ M. Furthermore, thiosemicarbazone compounds were found to be more efficient than thiazolidin-4-one derivatives. In addition, cyclic voltammetry was used to characterize the tested molecules, as well to estimate the experimental value of the energy band gap.

Keywords: essential oil; sesquiterpene hydrocarbon; hemisynthesis; thiosemicarbazone; thiazolidinone; crystal structure; computational chemistry; C—H

Cl hydrogen bonding; corrosion; polarization; DFT; cyclic voltammetry.

Read article Similar articles

Supporting information

	Crystallographic Information File (CIF) https://doi.org/10.1107/S2053229619005631/yo3060sup1.cif Contains datablock global
	Structure factor file (CIF format) https://doi.org/10.1107/S2053229619005631/yo3060Isup2.hkl Contains datablock I
	Tagged Image Format File (TIF) image https://doi.org/10.1107/S2053229619005631/yo3060sup3.tif 1H NMR spectra of compound 2
	Tagged Image Format File (TIF) image https://doi.org/10.1107/S2053229619005631/yo3060sup4.tif 13C NMR (APT) spectra of compound 2
	Tagged Image Format File (TIF) image https://doi.org/10.1107/S2053229619005631/yo3060sup5.tif 1H NMR spectra of compound 3
	Tagged Image Format File (TIF) image https://doi.org/10.1107/S2053229619005631/yo3060sup6.tif 13C NMR (APT) spectra of compound 3
	Tagged Image Format File (TIF) image https://doi.org/10.1107/S2053229619005631/yo3060sup7.tif 1H NMR spectra of compound 4
	Tagged Image Format File (TIF) image https://doi.org/10.1107/S2053229619005631/yo3060sup8.tif 13C NMR (APT) spectra of compound 4
	Tagged Image Format File (TIF) image https://doi.org/10.1107/S2053229619005631/yo3060sup9.tif 1H NMR spectra of compound 5
	Tagged Image Format File (TIF) image https://doi.org/10.1107/S2053229619005631/yo3060sup10.tif 13C NMR (APT) spectra of compound 5
	Tagged Image Format File (TIF) image https://doi.org/10.1107/S2053229619005631/yo3060sup11.tif 1H NMR spectra of compound 6
	Tagged Image Format File (TIF) image https://doi.org/10.1107/S2053229619005631/yo3060sup12.tif 13C NMR (APT) spectra of compound 6

CCDC reference: 1911992

Computing details top

Data collection: DUO in APEX2 (Bruker, 2012); cell refinement: SAINT (Bruker, 2012); data reduction: SAINT (Bruker, 2012); program(s) used to solve structure: SHELXS2014 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012) and DIAMOND (Brandenburg & Putz, 2012); software used to prepare material for publication: SHELXL2014 (Sheldrick, 2015).

Ethyl 2-{(Z)-2-{(Z)-[(1aR,5aR,9aS)-1,1-dichloro-1a,5,5,7-tetramethyl-1a,2,3,4,5,5a,8,9-octahydro-1H-benzo[a]cyclopropa[b][7]annulen-8-ylidene]hydrazono}-4-oxothiazolidin-3-yl)acetate top

Crystal data top

C₂₃H₃₁Cl₂N₃O₃S	D_x = 1.316 Mg m⁻³
M_r = 500.47	Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, P2₁2₁2₁	Cell parameters from 5789 reflections
a = 10.2769 (7) Å	θ = 2.0–27.5°
b = 12.2445 (7) Å	µ = 0.37 mm⁻¹
c = 20.0804 (13) Å	T = 299 K
V = 2526.8 (3) Å³	Block, colourless
Z = 4	0.34 × 0.21 × 0.11 mm
F(000) = 1056

Data collection top

Bruker DUO APEXII CCD diffractometer	4306 reflections with I > 2σ(I)
φ and ω scans	R_int = 0.056
Absorption correction: multi-scan (SADABS; Bruker, 2012)	θ_max = 27.5°, θ_min = 2.0°
T_min = 0.710, T_max = 0.746	h = −13→13
58280 measured reflections	k = −15→15
5789 independent reflections	l = −25→25

Refinement top

Refinement on F²	Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: full	H-atom parameters constrained
R[F² > 2σ(F²)] = 0.038	w = 1/[σ²(F_o²) + (0.0393P)² + 0.3269P] where P = (F_o² + 2F_c²)/3
wR(F²) = 0.089	(Δ/σ)_max < 0.001
S = 1.03	Δρ_max = 0.26 e Å⁻³
5789 reflections	Δρ_min = −0.19 e Å⁻³
294 parameters	Absolute structure: Flack x determined using 1538 quotients [(I+)-(I-)]/[(I+)+(I-)] (Parsons et al., 2013)
0 restraints	Absolute structure parameter: −0.04 (2)

Special details top

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
Cl1	0.91689 (9)	0.40874 (6)	0.28176 (4)	0.0521 (2)
Cl2	0.92163 (8)	0.64247 (6)	0.28263 (4)	0.0456 (2)
S1'	0.41368 (9)	0.18868 (7)	0.16736 (5)	0.0572 (3)
O1	0.5447 (3)	−0.10510 (19)	0.14607 (15)	0.0719 (8)
O2	0.7293 (3)	0.0766 (2)	0.02640 (14)	0.0716 (8)
O3	0.9255 (3)	0.0866 (3)	0.07238 (13)	0.0816 (9)
N1	0.6044 (2)	0.3561 (2)	0.15782 (13)	0.0447 (6)
N2	0.6657 (3)	0.2530 (2)	0.15405 (14)	0.0441 (7)
N3'	0.6216 (2)	0.06903 (19)	0.15379 (14)	0.0447 (7)
C1	0.9428 (3)	0.5258 (2)	0.23193 (14)	0.0334 (6)
C1A	1.0446 (3)	0.5220 (2)	0.17788 (15)	0.0341 (7)
C2	1.1211 (3)	0.6249 (2)	0.16433 (16)	0.0418 (7)
H2A	1.2050	0.6198	0.1863	0.050*
H2B	1.0751	0.6868	0.1831	0.050*
C3	1.1421 (3)	0.6439 (3)	0.08995 (18)	0.0538 (9)
H3A	1.2185	0.6032	0.0761	0.065*
H3B	1.1605	0.7208	0.0830	0.065*
C4	1.0282 (3)	0.6115 (3)	0.04491 (17)	0.0509 (9)
H4A	1.0515	0.6310	−0.0004	0.061*
H4B	1.0207	0.5326	0.0464	0.061*
C5	0.8934 (3)	0.6590 (2)	0.05887 (15)	0.0425 (8)
C5A	0.8460 (3)	0.6323 (2)	0.13161 (14)	0.0338 (7)
H5A	0.8799	0.6908	0.1600	0.041*
C6	0.7006 (3)	0.6342 (3)	0.13993 (15)	0.0406 (7)
H6	0.6597	0.7019	0.1379	0.049*
C7	0.6253 (3)	0.5472 (2)	0.14991 (15)	0.0387 (7)
C8	0.6826 (3)	0.4371 (2)	0.14911 (15)	0.0357 (7)
C9	0.8265 (3)	0.4258 (2)	0.13597 (16)	0.0361 (7)
H9A	0.8412	0.4166	0.0886	0.043*
H9B	0.8594	0.3614	0.1585	0.043*
C9A	0.8990 (3)	0.5258 (2)	0.16040 (13)	0.0300 (6)
C10	1.1226 (3)	0.4187 (2)	0.16751 (19)	0.0466 (8)
H10A	1.0659	0.3566	0.1703	0.070*
H10B	1.1885	0.4134	0.2013	0.070*
H10C	1.1630	0.4206	0.1244	0.070*
C11	0.8944 (4)	0.7841 (3)	0.05106 (19)	0.0587 (10)
H11A	0.9255	0.8029	0.0074	0.088*
H11B	0.9507	0.8156	0.0840	0.088*
H11C	0.8078	0.8119	0.0568	0.088*
C12	0.8010 (4)	0.6128 (3)	0.00546 (17)	0.0591 (10)
H12A	0.8294	0.6361	−0.0378	0.089*
H12B	0.7143	0.6389	0.0134	0.089*
H12C	0.8017	0.5344	0.0075	0.089*
C13	0.4803 (3)	0.5579 (3)	0.1594 (2)	0.0581 (10)
H13A	0.4360	0.5206	0.1240	0.087*
H13B	0.4566	0.6338	0.1589	0.087*
H13C	0.4560	0.5263	0.2013	0.087*
C2'	0.5817 (3)	0.1767 (2)	0.15774 (15)	0.0414 (7)
C4'	0.5249 (3)	−0.0091 (3)	0.15382 (17)	0.0501 (9)
C5'	0.3940 (3)	0.0420 (3)	0.1651 (2)	0.0565 (9)
H5'A	0.3576	0.0164	0.2068	0.068*
H5'B	0.3351	0.0218	0.1294	0.068*
C6'	0.7568 (3)	0.0426 (3)	0.14311 (17)	0.0479 (8)
H6'A	0.7701	−0.0348	0.1508	0.057*
H6'B	0.8099	0.0826	0.1748	0.057*
C7'	0.7990 (4)	0.0707 (3)	0.07342 (19)	0.0493 (9)
C8'	0.9852 (5)	0.1165 (6)	0.0093 (2)	0.1041 (19)
H8'A	1.0096	0.0512	−0.0151	0.125*
H8'B	0.9239	0.1576	−0.0176	0.125*
C9'	1.0974 (7)	0.1811 (5)	0.0221 (3)	0.133 (3)
H9'A	1.1409	0.1969	−0.0191	0.199*
H9'B	1.1553	0.1417	0.0510	0.199*
H9'C	1.0718	0.2481	0.0431	0.199*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Cl1	0.0539 (5)	0.0422 (4)	0.0601 (5)	0.0043 (4)	0.0065 (5)	0.0198 (4)
Cl2	0.0503 (5)	0.0425 (4)	0.0441 (4)	0.0020 (4)	−0.0012 (4)	−0.0076 (3)
S1'	0.0366 (5)	0.0501 (5)	0.0849 (7)	−0.0068 (4)	0.0104 (5)	−0.0062 (4)
O1	0.076 (2)	0.0378 (13)	0.102 (2)	−0.0106 (12)	0.0121 (16)	−0.0047 (13)
O2	0.0620 (19)	0.097 (2)	0.0559 (17)	−0.0111 (16)	−0.0092 (16)	−0.0069 (14)
O3	0.0451 (18)	0.150 (3)	0.0499 (16)	−0.0113 (19)	0.0077 (14)	0.0047 (16)
N1	0.0343 (15)	0.0404 (13)	0.0595 (17)	−0.0021 (13)	0.0024 (13)	−0.0069 (12)
N2	0.0354 (15)	0.0366 (14)	0.0602 (18)	−0.0060 (12)	0.0039 (14)	−0.0043 (12)
N3'	0.0388 (17)	0.0356 (13)	0.0597 (18)	−0.0024 (11)	0.0036 (14)	−0.0034 (12)
C1	0.0333 (17)	0.0264 (13)	0.0404 (16)	0.0001 (13)	−0.0001 (13)	0.0027 (12)
C1A	0.0274 (16)	0.0292 (13)	0.0456 (17)	0.0018 (12)	0.0017 (13)	0.0024 (13)
C2	0.0284 (17)	0.0387 (16)	0.058 (2)	−0.0035 (13)	0.0029 (15)	0.0018 (14)
C3	0.041 (2)	0.056 (2)	0.065 (2)	−0.0024 (17)	0.0117 (18)	0.0132 (18)
C4	0.052 (2)	0.053 (2)	0.047 (2)	0.0064 (17)	0.0104 (17)	0.0089 (16)
C5	0.049 (2)	0.0374 (16)	0.0415 (18)	0.0039 (15)	−0.0017 (16)	0.0042 (12)
C5A	0.0336 (17)	0.0287 (14)	0.0391 (16)	0.0035 (13)	−0.0022 (13)	0.0010 (12)
C6	0.0351 (18)	0.0371 (16)	0.0496 (19)	0.0112 (14)	−0.0046 (15)	0.0006 (14)
C7	0.0298 (17)	0.0434 (17)	0.0429 (18)	0.0051 (13)	−0.0020 (14)	−0.0071 (13)
C8	0.0289 (17)	0.0377 (16)	0.0406 (18)	−0.0004 (13)	−0.0006 (14)	−0.0046 (13)
C9	0.0288 (17)	0.0292 (14)	0.0501 (19)	0.0032 (12)	0.0006 (14)	−0.0034 (13)
C9A	0.0245 (15)	0.0264 (12)	0.0392 (15)	0.0025 (12)	0.0007 (13)	−0.0014 (12)
C10	0.0324 (18)	0.0387 (16)	0.069 (2)	0.0074 (14)	0.0046 (17)	0.0030 (15)
C11	0.073 (3)	0.0444 (19)	0.059 (2)	0.003 (2)	−0.004 (2)	0.0173 (15)
C12	0.069 (3)	0.061 (2)	0.048 (2)	0.007 (2)	−0.0091 (19)	0.0008 (17)
C13	0.033 (2)	0.066 (2)	0.075 (3)	0.0113 (17)	−0.0009 (19)	−0.011 (2)
C2'	0.0361 (17)	0.0424 (16)	0.0456 (18)	−0.0061 (15)	0.0042 (16)	−0.0044 (13)
C4'	0.051 (2)	0.046 (2)	0.054 (2)	−0.0124 (16)	0.0059 (17)	0.0001 (16)
C5'	0.044 (2)	0.054 (2)	0.071 (2)	−0.0187 (17)	0.0089 (19)	−0.0073 (17)
C6'	0.040 (2)	0.0479 (19)	0.056 (2)	0.0009 (16)	0.0027 (16)	−0.0011 (16)
C7'	0.043 (2)	0.051 (2)	0.053 (2)	−0.0010 (17)	0.0023 (19)	−0.0078 (16)
C8'	0.069 (3)	0.194 (6)	0.049 (3)	−0.023 (4)	0.021 (2)	−0.005 (3)
C9'	0.171 (7)	0.148 (5)	0.079 (4)	−0.076 (5)	0.042 (4)	−0.027 (3)

Geometric parameters (Å, º) top

Cl1—C1	1.768 (3)	C5A—H5A	0.9800
Cl2—C1	1.768 (3)	C6—C7	1.332 (4)
S1'—C2'	1.744 (3)	C6—H6	0.9300
S1'—C5'	1.808 (3)	C7—C8	1.472 (4)
O1—C4'	1.203 (4)	C7—C13	1.508 (5)
O2—C7'	1.188 (4)	C8—C9	1.509 (4)
O3—C7'	1.315 (5)	C9—C9A	1.515 (4)
O3—C8'	1.455 (5)	C9—H9A	0.9700
N1—C8	1.288 (4)	C9—H9B	0.9700
N1—N2	1.413 (3)	C10—H10A	0.9600
N2—C2'	1.274 (4)	C10—H10B	0.9600
N3'—C4'	1.380 (4)	C10—H10C	0.9600
N3'—C2'	1.383 (4)	C11—H11A	0.9600
N3'—C6'	1.442 (4)	C11—H11B	0.9600
C1—C9A	1.505 (4)	C11—H11C	0.9600
C1—C1A	1.508 (4)	C12—H12A	0.9600
C1A—C2	1.509 (4)	C12—H12B	0.9600
C1A—C10	1.512 (4)	C12—H12C	0.9600
C1A—C9A	1.538 (4)	C13—H13A	0.9600
C2—C3	1.527 (5)	C13—H13B	0.9600
C2—H2A	0.9700	C13—H13C	0.9600
C2—H2B	0.9700	C4'—C5'	1.501 (5)
C3—C4	1.532 (5)	C5'—H5'A	0.9700
C3—H3A	0.9700	C5'—H5'B	0.9700
C3—H3B	0.9700	C6'—C7'	1.505 (5)
C4—C5	1.529 (5)	C6'—H6'A	0.9700
C4—H4A	0.9700	C6'—H6'B	0.9700
C4—H4B	0.9700	C8'—C9'	1.421 (7)
C5—C11	1.539 (4)	C8'—H8'A	0.9700
C5—C12	1.540 (5)	C8'—H8'B	0.9700
C5—C5A	1.574 (4)	C9'—H9'A	0.9600
C5A—C6	1.504 (4)	C9'—H9'B	0.9600
C5A—C9A	1.527 (4)	C9'—H9'C	0.9600

C2'—S1'—C5'	91.40 (15)	C1—C9A—C9	117.1 (2)
C7'—O3—C8'	117.9 (3)	C1—C9A—C5A	117.9 (2)
C8—N1—N2	113.7 (2)	C9—C9A—C5A	113.1 (2)
C2'—N2—N1	110.5 (3)	C1—C9A—C1A	59.40 (19)
C4'—N3'—C2'	116.6 (3)	C9—C9A—C1A	121.9 (2)
C4'—N3'—C6'	122.6 (3)	C5A—C9A—C1A	117.3 (2)
C2'—N3'—C6'	120.5 (3)	C1A—C10—H10A	109.5
C9A—C1—C1A	61.37 (18)	C1A—C10—H10B	109.5
C9A—C1—Cl1	119.7 (2)	H10A—C10—H10B	109.5
C1A—C1—Cl1	119.2 (2)	C1A—C10—H10C	109.5
C9A—C1—Cl2	120.84 (19)	H10A—C10—H10C	109.5
C1A—C1—Cl2	121.6 (2)	H10B—C10—H10C	109.5
Cl1—C1—Cl2	108.09 (15)	C5—C11—H11A	109.5
C1—C1A—C2	117.8 (2)	C5—C11—H11B	109.5
C1—C1A—C10	119.5 (2)	H11A—C11—H11B	109.5
C2—C1A—C10	113.4 (2)	C5—C11—H11C	109.5
C1—C1A—C9A	59.22 (18)	H11A—C11—H11C	109.5
C2—C1A—C9A	116.2 (2)	H11B—C11—H11C	109.5
C10—C1A—C9A	120.6 (2)	C5—C12—H12A	109.5
C1A—C2—C3	112.2 (3)	C5—C12—H12B	109.5
C1A—C2—H2A	109.2	H12A—C12—H12B	109.5
C3—C2—H2A	109.2	C5—C12—H12C	109.5
C1A—C2—H2B	109.2	H12A—C12—H12C	109.5
C3—C2—H2B	109.2	H12B—C12—H12C	109.5
H2A—C2—H2B	107.9	C7—C13—H13A	109.5
C2—C3—C4	115.5 (3)	C7—C13—H13B	109.5
C2—C3—H3A	108.4	H13A—C13—H13B	109.5
C4—C3—H3A	108.4	C7—C13—H13C	109.5
C2—C3—H3B	108.4	H13A—C13—H13C	109.5
C4—C3—H3B	108.4	H13B—C13—H13C	109.5
H3A—C3—H3B	107.5	N2—C2'—N3'	119.6 (3)
C5—C4—C3	119.1 (3)	N2—C2'—S1'	128.0 (2)
C5—C4—H4A	107.6	N3'—C2'—S1'	112.3 (2)
C3—C4—H4A	107.6	O1—C4'—N3'	123.8 (3)
C5—C4—H4B	107.6	O1—C4'—C5'	125.3 (3)
C3—C4—H4B	107.6	N3'—C4'—C5'	110.9 (3)
H4A—C4—H4B	107.0	C4'—C5'—S1'	108.5 (2)
C4—C5—C11	110.7 (3)	C4'—C5'—H5'A	110.0
C4—C5—C12	106.9 (3)	S1'—C5'—H5'A	110.0
C11—C5—C12	107.4 (3)	C4'—C5'—H5'B	110.0
C4—C5—C5A	111.8 (3)	S1'—C5'—H5'B	110.0
C11—C5—C5A	107.7 (3)	H5'A—C5'—H5'B	108.4
C12—C5—C5A	112.3 (3)	N3'—C6'—C7'	111.4 (3)
C6—C5A—C9A	109.0 (2)	N3'—C6'—H6'A	109.3
C6—C5A—C5	114.0 (2)	C7'—C6'—H6'A	109.3
C9A—C5A—C5	114.7 (2)	N3'—C6'—H6'B	109.3
C6—C5A—H5A	106.1	C7'—C6'—H6'B	109.3
C9A—C5A—H5A	106.1	H6'A—C6'—H6'B	108.0
C5—C5A—H5A	106.1	O2—C7'—O3	125.1 (4)
C7—C6—C5A	125.5 (3)	O2—C7'—C6'	125.4 (3)
C7—C6—H6	117.2	O3—C7'—C6'	109.5 (3)
C5A—C6—H6	117.2	C9'—C8'—O3	108.9 (4)
C6—C7—C8	119.9 (3)	C9'—C8'—H8'A	109.9
C6—C7—C13	121.6 (3)	O3—C8'—H8'A	109.9
C8—C7—C13	118.5 (3)	C9'—C8'—H8'B	109.9
N1—C8—C7	117.0 (3)	O3—C8'—H8'B	109.9
N1—C8—C9	124.4 (3)	H8'A—C8'—H8'B	108.3
C7—C8—C9	118.6 (3)	C8'—C9'—H9'A	109.5
C8—C9—C9A	110.5 (2)	C8'—C9'—H9'B	109.5
C8—C9—H9A	109.5	H9'A—C9'—H9'B	109.5
C9A—C9—H9A	109.5	C8'—C9'—H9'C	109.5
C8—C9—H9B	109.5	H9'A—C9'—H9'C	109.5
C9A—C9—H9B	109.5	H9'B—C9'—H9'C	109.5
H9A—C9—H9B	108.1

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C10—H10A···Cl2ⁱ	0.96	2.79	3.557 (3)	137
C2—H2B···Cl1ⁱⁱ	0.97	2.81	3.661 (3)	147

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

Selected geometric parameters (Å, °) for 5 (reported here) and a–c (reported previously) top

Bond lengths	5	a*	b**	c***
Cl1—C1	1.768 (3)	1.757 (3)	1.763 (6)	1.769 (2)
Cl2—C1	1.768 (3)	1.762 (3)	1.766 (6)	1.761 (2)
N1—C8	1.287 (4)	—–	1.283 (7)	1.288 (2)
C6—C7	1.331 (5)	1.318 (4)	1.342 (8)	1.326 (3)
C7—C8	1.472 (4)	1.486 (4)	1.474 (8)	1.472 (2)
C8—C9	1.509 (4)	1.511 (4)	1.512 (7)	1.504 (2)

Cl1—C1—Cl2	108.1 (2)	107.6 (2)	108.2 (3)	108.8 (1)
C7—C8—C9	118.6 (3)	114.8 (2)	118.2 (4)	119.6 (2)
C6—C7—C8	119.9 (3)	121.4 (3)	120.2 (4)	119.0 (2)
N1—C8—C7	117.0 (3)	—–	116.3 (4)	116.3 (2)
N1—C8—C9	124.3 (3)	—–	125.4 (5)	124.2 (2)

References: (*) Auhmani et al. (1999); (**) Benharref et al. (2016); (***) Ourhriss et al. (2005).

Comparison of main bond lengths (Å) and C═N—N═C torsions angles (°) in the title compound and related structures top

N1—N2	C2'—N2	N1—C8	S1'—C2'	N3'—C2'	C═N—N═C	Reference
1.413 (4)	1.275 (5)	1.288 (4)	1.744 (4)	1.383 (4)	-174.7 (3)	This study
1.417 (3)	1.269 (3)	1.291 (3)	1.756 (3)	1.380 (3)	173.8 (3)	Gautam & Chaudhary (2015)
1.406 (2)	1.277 (2)	1.287 (2)	1.769 (2)	1.386 (2)	179.0 (2)	Hassan et al. (2017)
1.405 (3)	1.274 (3)	1.286 (4)	1.756 (3)	1.398 (3)	-168.9 (2)	N'ait Ousidi et al. (2017)
1.407 (2)	1.281 (2)	1.291 (2)	1.761 (2)	1.392 (2)	179.4 (2)	Mague et al. (2014)
1.414 (2)	1.278 (2)	1.278 (2)	1.749 (2)	1.367 (2)	-177.3 (2)	Ramachandran et al. (2009)
1.417 (7)	1.256 (7)	1.268 (8)	1.759 (5)	1.412 (8)	-177.6 (8)	Gupta & Chaudhary (2013)
1.410 (6)	1.279 (7)	1.279 (7)	1.767 (5)	1.364 (7)	174.9 (7)	Gautam et al. (2013)

Tafel parameters and corresponding inhibition efficiency derived from potentiodynamic polarization curves top

Inhibitor	E_corr (mV versus SCE)	i_corr (mA cm^-2)	η (%)
Blank	-378.7	305.9	–
1	-330.3	112.8	63.12
3	-327.7	129.9	57.53
5	-369.4	202.5	33.80
2	-376.2	23.6	92.28
4	-327.8	187.4	38.73
6	-311.3	132.2	56.78

Cyclic voltammetry parameters for the different tested molecules in a solution of 0.2 M Et₄NClO₄/acetonitrile at 100 mV s^-1. top

Molecules	E_ox^onset	E_HOMO	E_red^onset	E_LUMO	ΔE
1	0.235	-5.035	0.102	-4.902	0.133
2	-0.235	-4.565	-0.324	-4.476	0.089
3	0.537	-5.337	0.235	-5.035	0.302
4	0.271	-5.071	0.129	-4.929	0.142
5	0.572	-5.372	0.226	-5.026	0.346
6	0.182	-4.982	0.031	-4.831	0.151

Molecular properties of thiosemicarbazone and thiazolidin-4-one derivatives calculated using DFT at the B3LYP/6-31G(d) basis set. top

Molecule	1	2	4	6	3	5
E_HOMO	-0.201	-0.203	-0.216	-0.212	-0.217	-0.213
E_LUMO	-0.051	-0.053	-0.054	-0.053	-0.055	-0.053
ΔE	0.150	0.150	0.162	0.158	0.161	0.159
η	0.075	0.075	0.081	0.079	0.080	0.079
ΔE_T	-0.01875	-0.018	-0.020	-0.0198	-0.0202	-0.0198
ΔN	45.821	45.651	42.307	43.294	42.393	43.150
Dipôle/moment	7.295	6.696	3.738	3.834	3.881	4.085

Format		BIBTeX
		EndNote
		RefMan
		Refer
		Medline
		CIF
		SGML
		Text
		Plain Text

Format		BIBTeX
		EndNote
		RefMan
		Refer
		Medline
		CIF
		SGML
		Text
		Plain Text

Search IUCr Journals		doi		Advanced search
Author		volume	page

Hemisynthesis, crystal structure and inhibitory effect of sesquiterpenic thio­semicarbazones and thia­zolidin-4-ones on the corrosion behaviour of stainless steel in 1 M H2SO4 solution

Supporting information

Hemisynthesis, crystal structure and inhibitory effect of sesquiterpenic thiosemicarbazones and thiazolidin-4-ones on the corrosion behaviour of stainless steel in 1 M H₂SO₄ solution