Molecular compounds and complexes. V. Crystallography of equimolar aromatic hydrocarbon:l-X-2,4,6-trinitrobenzene molecular compounds. Crystal structure of fluoranthene: picryl bromide, polymorph I

Abstract

Crystal data are reported for the binary n-molecular compounds with naphthalene, anthracene, phenanthrene, acenaphthene, fluoranthene, pyrene or triphenylene as donor and 1,3,5-trinitrobenzene, picric acid, picryl chloride or picryl bromide as acceptor (33 different crystals have been studied). In three out of seven pairs, the trinitrobenzene and picric acid molecular compounds of a particular hydrocarbon are isomorphous, and in four out of seven pairs the picryl chloride and picryl bromide molecular compounds are isomorphous. The structure of fluoranthene:picryl bromide, polymorph I [monoclinic; a=7.664(8), b=8.035 (2), c=31-631 (8)/~,, fl=91-8 (1) °, space group P21/c, Z=4] has been solved by Patterson and Fourier methods and refined by block-diagonal least-squares calculations to a final R of 0.062. The structure consists of quasi-hexagonally close-packed mixed stacks of alternating donor and acceptor molecules. The stack axes are parallel to [100]. The interplanar spacing is 3.49 A, suggesting a rather weak charge-transfer interaction.

Synthesis, crystal growth, spectral, thermal and optical properties of acenaphthene picrate

“…In the DTA curve there is a sharp peak a t 163°C indicating the melting point of the material. This value is in good agreement with the value available in the literature (162°C) [12] and the experimentally determined value (160°C). The sharpness of the endothermic peak shows good degree of crystallinity of the material [14].…”

“…This paper reports the synthesis, solubility, growth aspect, linear, non linear, optical and the thermal properties of the title compound, whose SHG efficiency has been estimated to be 0.4 times that of m-nitro aniline [11]. The crystal belongs to the monoclinic system with the unit cell dimensions a=14.4Å, b=8.92 Å, c=6.85 Å, β=102° and space group C 2 [12].…”

Polyaromatic Hydrocarbon Inclusion Complexes with 2-Hydroxylpropyl-β/γ-Cyclodextrin: Molecular Dynamic Simulation and Spectroscopic Studies

“…This observation suggests a compact association between the guest and the host. The occurrence of two alternative binding mechanisms between the FLT molecule and 2-HP-β/γ-CD can be attributed to the discrepancy in width between the two sides of the FLT molecule [46]. The 2-HP-β-CD cone-shaped cavity forces the FLT to insert itself with its benzene ringside (Figure S6) to maximize the binding constant and minimize the steric hindrance.…”

Thermal investigation of solid-liquid equilibrium in the naphthalene (and some dimethyl derivatives)-picric acid systems

“…Because of their electron-donating properties, naphthalene and its methyl derivatives are able to form more or less stable EDA complexes with picric acid, with sharp melting points [5]. Compounds which form this kind of complex usually give a solid-liquid system with a compound which has a competitive melting point.…”

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The equilibria of the naphthalene-picric acid and the 2,3-and 2,6-dimethylnaphthalene-picric acid systems were subjected to thermal investigation.The naphthalene-picric acid system was earlier investigated by Kremann, Sapozhnikow and others [1,5]. In view of the divergence of their data, reinvestigation of this system was considered necessary.

Experimental

Materials

Chemically pure picric acid (2,4,6-TNF) (POCh, Gliwice) was dissolved in hot water and neutralized with a saturated solution of sodium carbonate.

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