Nitrogen nuclear quadrupole coupling constants and heavy atom substitution geometry of tert-butyl nitrite

Abstract

The microwave spectra of tert-butyl nitrite, including all of its heavy-atom singly substituted isotopomers, have been observed with a pulsed molecular beam microwave Fourier transform spectrometer. The analysis resulted in the following substitution structure parameters: r(O tN) = 118.18(8) pm, r(NO b) = 141.75(8) pm, r(O bC α ) = 143.75(6) pm, r(C α C i) = 152.34(3) pm, r(C α C o) = 152.90(4) pm, ∡(O tNO b) = 111.6(2)°, ∡(NO bC α) = 111.8(2)°, ∡(O bC αC i) = 103.0(1)° ∡(O bC αC o) = 110.1(1)°, and τ(NO bC α C o) = 61.6(1)°. The molecule has an ab-plane of symmetry. All measurements on the isotopically labeled species have been made using the isotopomers in their natural abundances. From the nuclear quadrupole hyperfine structures of the normal isotopic species and the [ 13C i]-labeled species, the elements of the nitrogen coupling tensor and its orientation in the bond axis system of the molecule have been determined to be χ zz = −5.53(17) MHz, χ xx = +2.15(17) MHz, χ yy = +3.377(1) MHz, and θ( a, x) = 24.3(13)°. Thus, the z-axis of the coupling tensor is inclined to the bisector of the O tNO b-angle by about 16.5° toward the O tN-bond.