2-Alkyltrinitrofluoren-9-ones 2 were conveniently synthesized by controlled nitration of 2-alkylfluoren-9-ones 5 with a mixture of red fuming HNO3 and concentrated H2SO4 at 0–25 °C. The precursors 5 were derived from the corresponding 2-acylfluorenes by appropriate reduction of the acyl function, followed by base-catalysed O2-oxidation at the C-9 position. The regiochemistry of nitration was interesting: with a sterically bulky substituent in 5, nitration occurred at C-4, -5, and -7 positions, affording 2-alkyl-4,5,7-trinitrofluoren-9-one in over 35% yield; on the other hand, 5 with a primary alkyl function underwent nitration predominantly at C-3, -5, and -7 positions. By virtue of its alkyl function, 2-alkyltrinitrofluoren-9-one 2 displayed better solubility and polymer compatibility characteristics than its non-alkylated analog, TNF. However, the charge transfer interactions of 2 with electron donors were weaker than those of TNF, despite the fact that they both have the same electron affinity. Both 2 and TNF exhibited good electron transport properties in poly(N-vinylcarbazole) matrices.

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This paper discusses the use of Rietveld analysis to solve crystal structures of titanyl phthalocyanines. Rietveld analysis is based on whole pattern fitting in which every point in the x-ray powder diffraction pattern is used as a measure of one or more Bragg diffraction peaks. Thus the refinement of relatively complicated crystal structures from x-ray patterns containing a relatively small number of resolved diffraction peaks is enabled. Various profile-fitting functions used in Rietveld analysis were parameterized and tested against known crystal structures of type I and type II titanyl phthalocyanine. It was found that a split Pearson VII function was found to best correct for preferred orientation effects observed in the x-ray patterns. The final goodness-of-fit parameters were R(Bragg) = 0.17 and 0.13 for type I and type II structures, respectively.A computer program was used to generate several unit cells for type IV titanyl phthalocyanine. These unit cells were tested by stereochemical packing analysis to first determine which unit cells allowed for good intermolecular packing arrangements. Energy minimized models were then used as phasing models for Rietveld refinement. A triclinic structure with space group P-i having an x-ray goodness-of-fit parameter R(Bragg) = 0.24 was proposed as the most probable crystal structure for type IV titanyl phthalocyanine. The unitcell parametersarea = 1.083 nm, b = 1.312 nm, c = 0.996 nm, alpha = 72.28 degrees, beta = 77.25 degrees and gamma = 104.48 degrees. There are two molecules in the unit cell related by a center of inversion. 160/ SPIE Vol. 1670 Color Hard Copy and Graphic Arts (1992) 0-81 94-0824-7/92/$4.00 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 07/07/2015 Terms of Use: http://spiedl.org/terms

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The spectroscopic properties of thiobinupharidine and its isomer, neothiobinupharidine, of established structure, have been examined and compared. From this study it was possible to deduce the structure and relative configuration of the alkaloid. The structure has been firmly established and the absolute configuration determined by the study of the crystal structure of thiobinupharidine dihydrobromide dihydrate, C30H42O2N2S•2HBr•2H2O. The crystals are orthorhombic with space group C2221, a = 25.128(6), b = 9.869(2), c = 26.380(6) Å, and Z = 8. The structure was refined, using full-matrix least-squares techniques with 1934 reflections, to a final R value of 0.097. The thiobinupharidine moiety hydrogen bonds to one of two types of H2O–Br–H2O spiral chains in the structure. The tetrahydrothiophene ring is distorted from planarity, and this together with the nonequivalence of the S and C atoms in the ring causes the molecule to deviate from C2 symmetry