
The [4π + 4π] photodimerization process of the 9-substituted anthracene derivative crystalline 9-methylanthracene (9-MA) was investigated using time-resolved X-ray powder diffraction. The study was carried out in-situ using a CCD area detector. Sequential and parametric Rietveld refinement was applied for quantitative phase analysis. The results of traditional sequential Rietveld refinement showed that the evolution of the dimerization process can be described using the Johnson–Mehl–Avrami–Kolmogorov (JMAK) model. The parameters of the JMAK equation were obtained successfully by parametric Rietveld refinement and suggest that the reaction follows heterogeneous nucleation and one-dimensional growth with a decreasing nucleation rate.
Keywords: time-resolved powder diffraction; photodimerization; parametric Rietveld refinement; 9-methylanthracene.
Supporting information
![]() | Crystallographic Information File (CIF) https://doi.org/10.1107/S0108768112027450/kd5063sup1.cif |
![]() | Rietveld powder data file (CIF format) https://doi.org/10.1107/S0108768112027450/kd5063sup2.rtv |
![]() | Text file https://doi.org/10.1107/S0108768112027450/kd5063sup3.txt |
![]() | Zip compressed file https://doi.org/10.1107/S0108768112027450/kd5063sup4.zip |
CCDC references: 898983; 898984
Computing details top
(9mai_phase_1) top
Crystal data top
C15H12 | α = 90° |
Mr = 192.25 | β = 96.95 (3)° |
P21/c | γ = 90° |
a = 8.679 (3) Å | V = 995.8 (5) Å3 |
b = 14.402 (3) Å | Z = 4 |
c = 8.026 (2) Å |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
x | y | z | Biso*/Beq | ||
C1 | 0.52341 | 0.67391 | −0.63768 | 5.061133 | |
C2 | 0.34886 | 0.58867 | −0.40048 | 6.016511 | |
C3 | 0.28187 | 0.61433 | −0.55182 | 6.008615 | |
C4 | 0.37155 | 0.65817 | −0.67376 | 5.045342 | |
C5 | 0.29169 | 0.68454 | −0.83685 | 4.768993 | |
C6 | 0.13995 | 0.66876 | −0.87299 | 5.637518 | |
C7 | 0.04945 | 0.62468 | −0.75006 | 5.598040 | |
C8 | 0.11635 | 0.59896 | −0.59875 | 4.792680 | |
C9 | 0.60258 | 0.64741 | −0.47441 | 3.837302 | |
C10 | 0.51403 | 0.60419 | −0.35414 | 4.074173 | |
C11 | 0.58307 | 0.57906 | −0.20373 | 3.782032 | |
C12 | 0.74955 | 0.59537 | −0.16014 | 3.947842 | |
C13 | 0.83113 | 0.63516 | −0.27097 | 3.758345 | |
C14 | 0.75406 | 0.66246 | −0.43603 | 3.608327 | |
C15 | 0.25377 | 0.54390 | −0.27803 | 5.755953 | |
H16 | 0.58266 | 0.70385 | −0.72263 | 6.790288 | |
H17 | 0.35073 | 0.71454 | −0.92194 | 7.500899 | |
H18 | 0.08639 | 0.68713 | −0.98552 | 6.395504 | |
H19 | −0.06425 | 0.61391 | −0.78089 | 6.316547 | |
H20 | 0.05293 | 0.56911 | −0.51749 | 4.737410 | |
H21 | 0.52145 | 0.54915 | −0.12085 | 6.711331 | |
H22 | 0.80194 | 0.57666 | −0.04729 | 7.579856 | |
H23 | 0.94487 | 0.64637 | −0.24148 | 6.000720 | |
H24 | 0.81494 | 0.69231 | −0.51964 | 4.421583 | |
H25 | 0.32188 | 0.52926 | −0.17171 | 4.537537 | |
H26 | 0.20651 | 0.48526 | −0.32756 | 5.723456 | |
H27 | 0.16959 | 0.58734 | −0.25325 | 4.162410 |
(9mai_phase_2) top
Crystal data top
C30H24 | α = 90° |
Mr = 384.49 | β = 115.14 (2)° |
P21/c | γ = 90° |
a = 9.851 (2) Å | V = 963.2 (4) Å3 |
b = 13.285 (3) Å | Z = 2 |
c = 8.1301 (17) Å |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
x | y | z | Biso*/Beq | ||
C1 | −0.69995 | 0.20518 | −0.12917 | 4.271565 | |
C2 | −0.84073 | 0.21201 | −0.13154 | 4.808471 | |
C3 | −0.88785 | 0.14246 | −0.04275 | 4.682140 | |
C4 | −0.79194 | 0.06565 | 0.05367 | 4.208399 | |
C5 | −0.29688 | −0.00003 | 0.44253 | 4.208399 | |
C6 | −0.15899 | 0.04597 | 0.52933 | 4.958489 | |
C7 | −0.11086 | 0.11372 | 0.43910 | 4.642662 | |
C8 | −0.20228 | 0.13722 | 0.25815 | 3.955737 | |
C9 | −0.54261 | −0.11867 | 0.03867 | 3.371457 | |
C10 | −0.54094 | −0.02335 | 0.16455 | 3.529371 | |
C11 | −0.60314 | 0.12852 | −0.03518 | 3.576745 | |
C12 | −0.64969 | 0.05881 | 0.05918 | 3.489892 | |
C13 | −0.38853 | 0.02324 | 0.26380 | 3.474101 | |
C14 | −0.34087 | 0.09297 | 0.16995 | 3.434622 | |
C15 | −0.60050 | −0.20748 | 0.11055 | 4.555809 | |
H1 | −0.67300 | 0.25221 | −0.19580 | 6.158633 | |
H2 | −0.91249 | 0.26827 | −0.21096 | 5.132194 | |
H3 | −0.99243 | 0.14901 | −0.04173 | 6.474461 | |
H4 | −0.81805 | 0.00966 | 0.12188 | 6.079676 | |
H5 | −0.33589 | −0.05533 | 0.50623 | 4.737410 | |
H6 | −0.08859 | 0.03207 | 0.65112 | 5.448022 | |
H7 | −0.00903 | 0.15009 | 0.50113 | 5.763849 | |
H8 | −0.17345 | 0.19186 | 0.18657 | 3.868885 | |
H10 | −0.57478 | −0.05518 | 0.25875 | 3.789928 | |
H15A | −0.52961 | −0.21912 | 0.24415 | 4.974281 | |
H15B | −0.72132 | −0.19136 | 0.09339 | 6.711331 | |
H15C | −0.61189 | −0.27147 | 0.03531 | 7.185072 |