ISSN:
1572-8854
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Geologie und Paläontologie
,
Physik
Notizen:
Abstract The X-ray crystal structures of two bicyclic diketones have been determined. 3,3,6,6-Tetramethylbicyclo[2.2.1]heptane-2,5-dione, C11H16O2 (A), is monoclinic,C2/c (No. 15), with cell dimensionsa=9.071(3),b=9.748(5),c=12.322(6)Å,β=110.15(3)°, andZ=4. The structure was determined by direct methods and refined toR 1=0.065,R 2=0.052 for 570 reflections. 6,6-Dibromo-1,3,3-trimethylbicyclo[2.2.2]octane-2,5-dione, C11H14Br2O2 (D), is orthorhombic,Pcab, (No. 61), with cell dimensionsa=11.206(3),b=18.818(6),c=11.695(4) Å, andZ=8. The structure was solved by the heavy-atom method and refined toR 1=0.070,R 2=0.065 for 1210 reflections. Bond lengths and angles within both structures do not differ from those in similar structures. The opening up of the internal ring angle of the ketone inA (vs. a normal bicyclo[2.2.1]heptane) and the consequent decrease of the adjacent internal ring angle brings the ketone carbon atoms nearer to the hydrogen atoms of the bridging methylene group.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF01159051
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