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The structure of 4-methyl-3-[(tetrahydro-2H-pyran-2-yl)oxy]thiazole-2(3H)-thione (MTTOTHP) was investigated using X-ray diffraction and computational chemistry methods for determining properties of the nitrogen—oxygen bond, which is the least stable entity upon photochemical excitation. Experimentally measured structure factors have been used to determine and characterize charge density via the multipole model (MM) and the maximum entropy method (MEM). Theoretical investigation of the electron density and the electronic structure has been performed in the finite basis set density functional theory (DFT) framework. Quantum Theory of Atoms In Molecules (QTAIM), deformation densities and Laplacians maps have been used to compare theoretical and experimental results. MM experimental results and predictions from theory differ with respect to the sign and/or magnitude of the Laplacian at the N—O bond critical point (BCP), depending on the treatment of n values of the MM radial functions. Such Laplacian differences in the N—O bond case are discussed with respect to a lack of flexibility in the MM radial functions also reported by Rykounov et al. [Acta Cryst. (2011), B67, 425–436]. BCP Hessian eigenvalues show qualitatively matching results between MM and DFT. In addition, the theoretical analysis used domain-averaged fermi holes (DAFH), natural bond orbital (NBO) analysis and localized (LOC) orbitals to characterize the N—O bond as a single σ bond with marginal π character. Hirshfeld atom refinement (HAR) has been employed to compare to the MM refinement results and/or neutron dataset C—H bond lengths and to crystal or single molecule geometry optimizations, including considerations of anisotropy of H atoms. Our findings help to understand properties of molecules like MTTOTHP as progenitors of free oxygen radicals.
Keywords: quantum crystallography; maximum entropy method; multipole model; charge density; homolytic cleavage; quantum information crystallography; O-alkyl thiohydroxamate; N,O-bond order; hydroxylamine derivative.
Supporting information
 | Crystallographic Information File (CIF) https://doi.org/10.1107/S2052520620005533/px5018sup1.cif |
 | Structure factor file (CIF format) https://doi.org/10.1107/S2052520620005533/px5018Isup2.hkl |
 | Portable Document Format (PDF) file https://doi.org/10.1107/S2052520620005533/px5018sup3.pdf |
CCDC reference: 1998099
Computing details top
Program(s) used to solve structure: SHELXS (Sheldrick, 2008); program(s) used to refine structure: Volkov et al., (2006); molecular graphics: Volkov et al., (2006); software used to prepare material for publication: Volkov et al., (2006).
4-Methyl-3-[(tetrahydro-2H-pyran-2-yl) oxy] thiazole-2(3H)-thione top
Crystal data top
| C9H13NO2S2 | F(000) = 488 |
| Mr = 231.32 | Dx = 1.426 Mg m−3 |
| Monoclinic, P21/n | Ag Kα radiation, λ = 0.56083 Å |
| a = 9.8106 (1) Å | Cell parameters from 529944 reflections |
| b = 10.5345 (1) Å | θ = 2.2–46.1° |
| c = 10.4312 (1) Å | µ = 0.24 mm−1 |
| β = 91.787 (1)° | T = 100 K |
| V = 1077.54 (2) Å3 | Block, colourless |
| Z = 4 | 0.51 × 0.35 × 0.16 mm |
Data collection top
| STOE STADIVARI diffractometer | 18518 independent reflections |
| Radiation source: Ag-Ims | 11715 reflections with I > 3u(I) |
| Graded multilayer mirror monochromator | Rint = 0.034 |
| Detector resolution: 5.81 pixels mm-1 | θmax = 45.4°, θmin = 2.2° |
| rotation method, ω scans | h = → |
| Absorption correction: multi-scan STOE X-Red32, absorption correction by Gaussian integration, analogous to P. Coppens, "The Evaluation of Absorption and Extinction in Single-Crystal Structure Analysis", published in: F. R. Ahmed (Editor), "Crystallographic Computing", Munksgaard, Copenhagen (1970), 255 - 270. Afterwards scaling of reflection intensities was performed within STOE LANA. J. Koziskova, F. Hahn, J. Richter, J. Kozisek, "Comparison of different absorption corrections on the model structure of tetrakis(µ2-acetato)- diaqua-di-copper(II)", Acta Chimica Slovaca, vol. 9, no. 2, 2016, pp. 136 - 140. Finally a spherical absorption correction was done within STOE LANA. | k = → |
| Tmin = 0.903, Tmax = 0.963 | l = → |
| 440543 measured reflections |
Refinement top
| Refinement on F2 | 413 parameters |
| Least-squares matrix: full | 0 restraints |
| R[F2 > 2σ(F2)] = 0.014 | w2 = q/[s2(Fo2) + (0.00 P)2 + 0.00 P + 0.00 + 0.00 sin(th)]
where P = (0.3333 Fo2 + 0.6667 Fc2) q = 1.0 |
| wR(F2) = 0.017 | (Δ/σ)max < 0.001 |
| S = 1.87 | Δρmax = 0.37 e Å−3 |
| 12400 reflections | Δρmin = −0.29 e Å−3 |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
| x | y | z | Uiso*/Ueq | ||
| S(1) | 0.102218 (3) | 0.482351 (3) | 0.360218 (3) | 0.015 | |
| S(2) | 0.190959 (4) | 0.266802 (3) | 0.535950 (3) | 0.018 | |
| O(1) | 0.436098 (15) | 0.293625 (14) | 0.361682 (15) | 0.012 | |
| O(2) | 0.622215 (16) | 0.411857 (16) | 0.445837 (17) | 0.014 | |
| N(1) | 0.331016 (14) | 0.379630 (13) | 0.346747 (14) | 0.01 | |
| C(1) | 0.213376 (16) | 0.537698 (14) | 0.246869 (16) | 0.015 | |
| C(2) | 0.332430 (14) | 0.472764 (13) | 0.251677 (13) | 0.011 | |
| C(3) | 0.524651 (15) | 0.321375 (13) | 0.475085 (14) | 0.013 | |
| C(4) | 0.58362 (2) | 0.193834 (17) | 0.516680 (19) | 0.019 | |
| C(5) | 0.68854 (2) | 0.145116 (18) | 0.42264 (2) | 0.023 | |
| C(6) | 0.795618 (19) | 0.248690 (19) | 0.40383 (2) | 0.023 | |
| C(7) | 0.725435 (16) | 0.369860 (17) | 0.359499 (18) | 0.017 | |
| C(8) | 0.453126 (17) | 0.489841 (17) | 0.170870 (17) | 0.016 | |
| C(9) | 0.216758 (14) | 0.368450 (13) | 0.416394 (14) | 0.012 | |
| H(1) | 0.185239 (16) | 0.613250 (14) | 0.180943 (16) | 0.0350 (12)* | |
| H(3) | 0.460165 (15) | 0.364298 (13) | 0.547667 (14) | 0.0206 (9)* | |
| H(4A) | 0.49879 (2) | 0.128377 (17) | 0.529349 (19) | 0.0353 (12)* | |
| H(4B) | 0.63219 (2) | 0.206916 (17) | 0.611380 (19) | 0.0382 (12)* | |
| H(5A) | 0.73337 (2) | 0.057310 (18) | 0.46027 (2) | 0.0465 (13)* | |
| H(5B) | 0.63862 (2) | 0.123306 (18) | 0.33022 (2) | 0.0389 (12)* | |
| H(6A) | 0.853236 (19) | 0.265452 (19) | 0.49349 (2) | 0.0442 (14)* | |
| H(6B) | 0.868948 (19) | 0.222585 (19) | 0.33173 (2) | 0.0548 (14)* | |
| H(7A) | 0.796731 (16) | 0.449146 (17) | 0.354126 (18) | 0.0328 (11)* | |
| H(7B) | 0.679299 (16) | 0.356287 (17) | 0.263857 (18) | 0.0330 (11)* | |
| H(8A) | 0.539296 (17) | 0.520141 (17) | 0.229630 (17) | 0.0342 (11)* | |
| H(8B) | 0.429582 (17) | 0.562142 (17) | 0.100617 (17) | 0.0383 (12)* | |
| H(8C) | 0.477234 (17) | 0.401787 (17) | 0.124261 (17) | 0.0380 (12)* |
Atomic displacement parameters (Å2) top
| U11 | U22 | U33 | U12 | U13 | U23 | |
| S(1) | 0.010186 (12) | 0.018463 (15) | 0.017517 (15) | 0.002122 (10) | 0.001221 (9) | −0.001105 (11) |
| S(2) | 0.019804 (16) | 0.018871 (15) | 0.014986 (15) | −0.005463 (11) | 0.003891 (11) | 0.003519 (11) |
| O(1) | 0.01220 (5) | 0.00970 (4) | 0.01247 (5) | 0.00087 (4) | −0.00180 (4) | −0.00117 (4) |
| O(2) | 0.01169 (5) | 0.01214 (5) | 0.01667 (6) | 0.00068 (4) | −0.00111 (5) | −0.00392 (5) |
| N(1) | 0.00982 (4) | 0.01034 (4) | 0.01086 (5) | 0.00010 (4) | 0.00050 (4) | 0.00121 (4) |
| C(1) | 0.01396 (5) | 0.01405 (5) | 0.01593 (6) | 0.00293 (4) | −0.00056 (4) | 0.00255 (4) |
| C(2) | 0.01137 (4) | 0.01135 (5) | 0.01142 (5) | 0.00042 (4) | 0.00058 (4) | 0.00168 (4) |
| C(3) | 0.01380 (5) | 0.01179 (5) | 0.01244 (5) | 0.00168 (4) | −0.00194 (4) | −0.00056 (4) |
| C(4) | 0.02300 (7) | 0.01481 (6) | 0.01980 (7) | 0.00391 (5) | −0.00551 (6) | 0.00292 (5) |
| C(5) | 0.02392 (8) | 0.01522 (6) | 0.02806 (9) | 0.00805 (6) | −0.00624 (7) | −0.00427 (6) |
| C(6) | 0.01578 (6) | 0.02230 (8) | 0.03139 (9) | 0.00807 (6) | −0.00381 (7) | −0.00625 (7) |
| C(7) | 0.01238 (5) | 0.01864 (6) | 0.02101 (7) | 0.00225 (5) | 0.00031 (5) | −0.00415 (5) |
| C(8) | 0.01515 (5) | 0.01829 (6) | 0.01527 (6) | −0.00023 (5) | 0.00352 (5) | 0.00433 (5) |
| C(9) | 0.01149 (5) | 0.01349 (5) | 0.01213 (5) | −0.00161 (4) | 0.00152 (4) | 0.00053 (4) |
Geometric parameters (Å, º) top
| S(1)—C(1) | 1.7343 (2) | C(4)—H(4B) | 1.0920 (1) |
| S(1)—C(9) | 1.7334 (1) | C(5)—C(6) | 1.5315 (3) |
| S(2)—C(9) | 1.6690 (1) | C(5)—H(5A) | 1.0920 (1) |
| O(2)—C(3) | 1.3914 (2) | C(5)—H(5B) | 1.0920 (1) |
| N(1)—C(2) | 1.3954 (2) | C(6)—C(7) | 1.5157 (2) |
| N(1)—C(9) | 1.3598 (2) | C(6)—H(6A) | 1.0920 (1) |
| C(1)—C(2) | 1.3531 (2) | C(6)—H(6B) | 1.0920 (1) |
| C(1)—H(1) | 1.0820 (1) | C(7)—H(7A) | 1.0920 (1) |
| C(2)—C(8) | 1.4857 (2) | C(7)—H(7B) | 1.0920 (1) |
| C(3)—C(4) | 1.5207 (2) | C(8)—H(8A) | 1.0770 (1) |
| C(3)—H(3) | 1.0990 (1) | C(8)—H(8B) | 1.0770 (1) |
| C(4)—C(5) | 1.5323 (3) | C(8)—H(8C) | 1.0770 (1) |
| C(4)—H(4A) | 1.0920 (1) | ||
| C(1)—S(1)—C(9) | 92.774 (7) | C(6)—C(5)—H(5B) | 109.105 (12) |
| C(2)—N(1)—C(9) | 117.855 (13) | H(5A)—C(5)—H(5B) | 107.6790 (1) |
| S(1)—C(1)—C(2) | 111.418 (11) | C(5)—C(6)—C(7) | 109.401 (15) |
| S(1)—C(1)—H(1) | 121.819 (5) | C(5)—C(6)—H(6A) | 110.138 (12) |
| C(2)—C(1)—H(1) | 126.743 (9) | C(5)—C(6)—H(6B) | 112.215 (11) |
| N(1)—C(2)—C(1) | 110.737 (13) | C(7)—C(6)—H(6A) | 110.071 (11) |
| N(1)—C(2)—C(8) | 120.939 (13) | C(7)—C(6)—H(6B) | 107.744 (11) |
| C(1)—C(2)—C(8) | 128.321 (14) | H(6A)—C(6)—H(6B) | 107.2178 (1) |
| O(2)—C(3)—C(4) | 114.181 (14) | C(6)—C(7)—H(7A) | 111.975 (10) |
| O(2)—C(3)—H(3) | 106.494 (9) | C(6)—C(7)—H(7B) | 109.867 (11) |
| C(4)—C(3)—H(3) | 112.893 (10) | H(7A)—C(7)—H(7B) | 107.5277 (1) |
| C(3)—C(4)—C(5) | 111.742 (16) | C(2)—C(8)—H(8A) | 109.776 (9) |
| C(3)—C(4)—H(4A) | 107.928 (10) | C(2)—C(8)—H(8B) | 108.292 (8) |
| C(3)—C(4)—H(4B) | 107.336 (9) | C(2)—C(8)—H(8C) | 109.997 (9) |
| C(5)—C(4)—H(4A) | 113.307 (11) | H(8A)—C(8)—H(8B) | 108.9975 (1) |
| C(5)—C(4)—H(4B) | 109.789 (10) | H(8A)—C(8)—H(8C) | 109.4295 (1) |
| H(4A)—C(4)—H(4B) | 106.4330 (1) | H(8B)—C(8)—H(8C) | 110.3278 (1) |
| C(4)—C(5)—C(6) | 108.696 (15) | S(1)—C(9)—S(2) | 125.795 (8) |
| C(4)—C(5)—H(5A) | 108.943 (10) | S(1)—C(9)—N(1) | 107.214 (11) |
| C(4)—C(5)—H(5B) | 110.116 (10) | S(2)—C(9)—N(1) | 126.980 (12) |
| C(6)—C(5)—H(5A) | 112.292 (10) |
