The molecular structure of uracil: an electron diffraction study
Abstract
The molecular structure of free uracil has been determined by electron diffraction. Planar or nearly planar models fit the experimental data. Differences between the four CN bond lengths as well as those between the two CO bond lengths were assumed from ab initio (4-21) calculations in the electron diffraction analysis. The following bond lengths ( rg) and bond angles ( rα) were determined; the estimated total errors are parenthesized as expressed in units of the last digit: r(CN) mean 1.399(6), r(CC) 1.462(8), r(CC) 1.343(24), r(CO) mean 1.212(3) Å, C 2N 1C 6 123.2(12), N 3C 4C 5 115.5(18), C 4C 5C 6 119.7(21), C 5C 6N 1 122.1(22), N 1C 2O 8 123.8(14), C 5C 4O 10 124.3(20)°. The structural parameters by electron diffraction are in agreement with those by quantum chemical optimizations (ab initio 4-21, MINDO/3). The bond lengths indicate partial delocalization in the ring.
- Publication:
-
Journal of Molecular Structure
- Pub Date:
- January 1986
- DOI:
- 10.1016/0022-2860(86)80148-X
- Bibcode:
- 1986JMoSt.140...71F