A Second Triclinic Polymorph of Coumarin 153

Abstract

YVES DROMZEE et al. 477 was chosen on the basis of statistical tests and confirmed by subsequent results. In the /3 form, the observed systematic absences Okl, k = 2n + 1, hOl, l = 2n + 1, and hkO, h + k = 2n + 1, indicated space group Pbcn. Computations were performed using CRYSTALS (Watkin, Carruthers & Betteridge, 1988) adapted on a MicroVAXII. Scattering factors for all atoms were as incorporated in CRYSTALS. The structures were solved by direct methods. All remaining non-H atoms were found by successive electron-density map calculations. For the /3 (orthorhombic) form, the density map showed two prominent but unequal peaks, one on either side of the plane. The only satisfactory explanation of this was the assumption of a disordered model. Fractional oxygen, referred to as O(1) and O(2), was assigned to these two positions, with occupancy factors summing to unity and with the same isotropic displacement parameters. The refinement of occupancy led to 0.69 for O(1) and 0.31 for 0(2). Atomic coordinates were refined together with anisotropic displacement parameters [isotropic for 0(2)]. At this stage, the H atoms were located on a difference electron-density map, their coordinates refined with an overall isotropic displacement parameter and then included as fixed contributors for further structure-factor calculations. Least-squares refinements were carded out by minimizing the function ~w (lFol-lFcl) z. The models reached convergence with R and wR having the values listed. The criteria for a satisfactory complete analysis were the ratios of the r.m.s, shift to standard deviation being less than 0.1 and there being no significant features in the final difference maps.Lists of structure factors, anisotropic displacement parameters, Hatom coordinates and complete geometry have been deposited with the IUCr (Reference: PAl 162). Copies may be obtained through The Managing Editor, International Union of Crystallography, 5 Abbey Square, Chester CH 1 2HU, England. ReferencesChiarelli, R., Novak, M. A., Rassat, A. & Tholence, J. L. (1993). Nature, 363, 147-149. Chiarelli, R. & Rassat, A. (1991) . AbstractCoumarin 153, 2,3,6,7-tetrahydro-9-(trifluoromethyl)-1 H, 5H, 11 H-[ 1 ]benzopyrano [6,7,8-o]quinolizin-11-one, CI6H14F3NO2, was found to exist in a new polymorphic form in the triclinic system. There is an earlier report of a crystal structure determination of this compound, also in the triclinic system, but with a different cell volume and packing mode [Gridunova et al. (1992). Kristallografiya, 37,[366][367][368][369][370][371][372]. There are three molecules in the asymmetric unit of the title polymorph compared with two in the latter case; all three molecules show disorder in the piperidine ring system. The molecules are planar and are stacked parallel to the (011) plane. The crystal structure is stabilized by C--H---O hydrogen bonds. CommentThe title compound, (I), a dgidized aminocoumarin, has attracted extensive study since it has been used as a laser dye (Maeda, 1984; Pdyadarsini, Naik & Moorthy, 1989...

Experimental and Theoretical Charge Density Analysis of Polymorphic Structures: The Case of Coumarin 314 Dye

“…A wide variety of pharmacological activities, such as antiviral and antimicrobial activity, are exhibited by coumarin derivatives, and they form the basic building block in the well-known antibiotic novobiocin . Coumarin dyes such as coumarin 138, coumarin 152, coumarin 153, and coumarin 314 , are found to exist in two different crystalline forms. The phenomenon, existence of a crystal structure in more than one crystalline form, is known as polymorphism .…”

Concomitant Polymorphism in 3-Acetylcoumarin: Role of Weak C−H···O and C−H···π Interactions

“…Polymorphism is the ability of a chemical substance to exist in at least two different crystal forms, which usually display different physical and chemical properties . Several coumarin dyes, such as coumarin 138, comarin 152, coumarin 153, and coumarin 314 exhibit polymorphism. Concomitant polymorphs have also been identified in 4-styrylcoumarin and its 3-fluoro derivative .…”

10-Acetyl-2,3,6,7-tetrahydro-1H,5H,11H-1-benzopyrano[6,7,8-ij]quinolizin-11-one

“…For related structures, see: Honda et al (1996a,b); Gridunova et al (1992); Yip et al (1996). For related background, see: Pawar & Mulwad (2004); Lin et al (2006); Urano et al (1995); Zhang et al (2003); Aggarwal et al (1996).…”