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Crystal Research and Technology |
Cryst. Res. Technol. 43, 205 (2008) - Abstract -
Synthesis and crystal structure determination of two dispiro compounds from laboratory x-ray powder diffraction data
A. M. Moustafa, R. E. Dinnebier, S. T. Nasser, and M. Jansen
Max Planck Institute for Solid State Research, Heisenbergstrasse 1, 70569 Stuttgart, Germany
| Keywords | powder diffraction, x-ray, crystalline solids, structure determination |
| PACS | 61.10.Nz, 61.66.-F, 61.68.+n |
| DOI | 10.1002/crat.200710976 |
The crystal structures of the dispiro compounds 1,3,4,8,10,11-Hexaphenyl-13-methyl-1,2,8,9,13-pentaazadispiro[4.1.4.3]tetradeca-2,9-dien-6-one (3a) and 4,11-Bis(4-methoxyphenyl)-13-methyl-1,3,8,10-tetraphenyl-1,2,8,9,13-pentaazadispiro-[4.1.4.3]tetradeca-2,9-dien-6-one (3b) have been determined at room temperature from X-ray powder diffraction data using the method of simulated annealing as implemented in the programs DASH and TOPAS. Subsequent Rietveld refinements using the data collected to 1.5 Å resolution yielded R-Bragg values of 2.2 % for (3a) and 3.7 % for (3b). It was found, that both compounds crystallize in the monoclinc space group P21/n with lattice parameters of a = 17.1656(5) Å, b=13.8128(3) Å, c= 16.1016(5) Å, and β = 103.7330(2)° for (3a) and a = 17.2529(8) Å, b = 13.8729(5) Å, c=16.1287(10) Å, and β = 103.6910(3)° for (3b). Both compounds exhibit a distorted hexagonal close type of packing (hcp) of the molecular centers of gravity.
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