Biomaterial Database

Shapes of benz[a]anthracenes: the crystal and molecular structure of 6-methylbenz[a]anthracene. 1990

D W Jones, and J D Shaw

Department of Chemistry and Chemical Technology, University of Bradford, West Yorkshire, England.

The crystal structure of 6-methylbenz[a]anthracene (6-MBA), a more potent carcinogen than the other K-region monomethyl-substituted benz[a]anthracene (5-MBA), has been determined by application of direct methods to single-crystal X-ray diffractometric data and refined by least squares to R = 0.047 (Rw = 0.053). Deviations of the carbon atoms from planarity are very small with even the methyl carbon displaced by only 0.05 A from the mean molecular plane. The benzo-ring A is inclined at only about 1 1/2 degrees to each of the three rings in the anthracene moiety, i.e. 6-MBA is one of the most nearly planar benz[a]anthracenes. The K-region bond C(5)-C(6) = 1.328(6) A and two other short bonds are C(8)-C(9) = 1.341(7) and C(10)-C(11) = 1.361(7) A in the anthracene D ring.

UI	MeSH Term	Description	Entries
D001551	Benz(a)Anthracenes	Four fused benzyl rings with three linear and one angular, that can be viewed as a benzyl-phenanthrenes. Compare with NAPHTHACENES which are four linear rings.	Benz(b)Phenanthrenes,Naphthanthracenes
D014961	X-Ray Diffraction	The scattering of x-rays by matter, especially crystals, with accompanying variation in intensity due to interference effects. Analysis of the crystal structure of materials is performed by passing x-rays through them and registering the diffraction image of the rays (CRYSTALLOGRAPHY, X-RAY). (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)	Xray Diffraction,Diffraction, X-Ray,Diffraction, Xray,Diffractions, X-Ray,Diffractions, Xray,X Ray Diffraction,X-Ray Diffractions,Xray Diffractions
D015394	Molecular Structure	The location of the atoms, groups or ions relative to one another in a molecule, as well as the number, type and location of covalent bonds.	Structure, Molecular,Molecular Structures,Structures, Molecular