ISSN:
1572-8854
Source:
Springer Online Journal Archives 1860-2000
Topics:
Geosciences
,
Physics
Notes:
Abstract The title compound, C20H14O8, Mr=382.3, crystallized from chloroform in the centric space group P¯1 witha=6.516(4),b=6.798(3),c=9.545(7) Å,α=85.31(5),β=73.87(5), γ=79.59(4)°,V=399.2 Å3, and Dcalc=1.59 g cm−3 forZ=1. Least-squares refinement of 1035 observed [Fo≥5σ(Fo)] reflections led to the final agreement index ofR=0.074. The molecule resides on a crystallographic center of inversion and is disordered into two different conformations. This manifests itself as a 50/50 disorder at O(4), C(2), and C(3). The observed structure reveals acis relationship between the bridgehead hydrogen atoms and the aryl rings. The 90 MHz1H nmr spectrum of the title compound exhibits an AA′XX′ spin system with a H(1)C(2) to H(1)C(3) and H(1)C(2)′ to H(1)C(3)′ coupling constant of 2.8 Hz. Computer spectral simulation and Karplus equation analysis are utilized to illustrate a relaxation of the torsion angles between H(1)C(2) and H(1)C(3), and H(1)C(2)′ and H(1)C(3)′ is solution.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01274139
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