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The microwave spectrum, dipole moment, and nuclear quadrupole coupling constants of pyrimidine

1970; Elsevier BV; Volume: 35; Issue: 3 Linguagem: Inglês

10.1016/0022-2852(70)90185-2

1096-083X

G. L. Blackman, Ronald D. Brown, Frank R. Burden,

Atmospheric Ozone and Climate

The microwave spectrum of pyrimidine has been observed between 8000 MHz and 18,000 MHz. The rotational constants are A = 6276.86 MHz, B = 6067.18 MHz, and C = 3084.49 MHz. These results agree with earlier work on this molecule. The dipole moment measured by the Stark effect is 2.334 ± 0.010 D ((7.785 ± 0.030) × 10−30 C.m). From an analysis of the hyperfine structure on a number of rotational transitions, the three diagonal elements of the nuclear quadrupole coupling tensor in the principal inertial axis system were obtained. They are χaa = −3.107 ± 0.014 MHz, χbb = −0.223 ± 0.016 MHz, and χcc = 3.330 ± 0.014 MHz. The success with which nitrogen coupling constants in other aza-derivatives of aromatic hydrocarbons can be predicted by using the experimental data of pyridine is illustrated.