Structure Data of Free Polyatomic Molecules
581
MW
C4H9FO
Tetrahydrofuran – hydrogen fluoride (1/1)
Cs
(weakly bound complex)
(effective symmetry class)
(large-amplitude motion)
O . HF
Ring
form
T5–
B3+
T1+
B4–
T2–
r0(O...F)
[Å] a)
2.5988(25)
2.5182(17)
2.5979(17)
2.6896(29)
2.7666(41)
r0(O...H) b)
[Å]
1.556
1.606
1.682
1.770
1.845
θ0(φ) c)
[deg]
54
72
90
108
126
θ0(β) d)
a
[deg] )
149.719(66)
138.658(43)
125.140(42)
110.495(70)
99.795(97)
θ0(γ) b) d)
[deg]
43.36
47.48
51.27
56.19
59.66
θ0(α) b) d)
[deg]
14.5
12.4
10.1
7.8
6.3
The rotational spectra of C4H8O ⋅ HF and C4H8O ⋅ DF
exhibit small tunneling splittings, which were not
observed for C4D8O ⋅ HF and the four single 13C
isotopomers. From the analysis of these observations
in terms of symmetry considerations, these splittings
were ascribed to pseudorotation within the
tetrahydrofuran subunit of the complex and not to
HF inversion. The spectroscopic parameters of the
complex were interpreted in terms of a geometry in which tetrahydrofuran has a conformation
close to the twisted ring form, with HF lying on the plane bisector to the COC ring angle.
a
) Estimated standard errors.
) Derived parameters.
c
) Pseudorotation angle.
d
) See figure for the definition.
b
Alonso, J.L., López, J.C., Blanco, S.B., Lesarri, A., Lorenzo, F.J.: J. Chem. Phys. 113 (2000)
2760.
Landolt-Börnstein
New Series II/28C