The 14 μm bands of BF3–CO complexes: Isotope-dependent chaotic fine structure

Abstract

Infrared absorption spectra of jet-cooled four isotopic 10,11BF3–12,13CO complexes are studied in the 14 μm region. The spectra of the 10BF3–12CO and 10BF3–13CO complexes are parallel bands with unresolved K-structure characteristic of a heavy symmetric top molecule. On the other hand, the spectra of the 11BF3–12CO and 11BF3–13CO complexes exhibit a complicated fine structure that cannot be interpreted by an ordinary semirigid molecular model. All of the observed bands are shifted to the red by 28–30 cm−1 from the ν3 band origin of uncomplexed BF3, indicating a considerable increase in bond energies by the vibrational excitation. Possible origins of the anomalous fine structure are discussed.

Van der Waals Complexes between Boron Trifluoride and Carbon Monoxide in Liquefied Argon: An Infrared Study

“…For ν 3 ( 10 B) in the same way for the vapor phase a BF 3 ·Ar to BF 3 ·CO shift equal to −6.159 cm -1 is calculated from the published data. , In very good agreement with this value, in liquid argon a frequency difference of −6.03 cm -1 is found.…”

“…If it is assumed that this substitution does not alter the solvation shell, then the complexation shifts in liquid argon must be the same as the vapor phase shifts from BF 3 ·Ar to BF 3 ·CO. In the gas phase, the shift of ν 2 from 11 BF 3 ·Ar to 11 BF 3 ·CO is obtained by subtracting the shift from 11 BF 3 to 11 BF 3 ·Ar, −5.710 cm -1 , from the shift from 11 BF 3 to 11 BF 3 ·CO, −27.180 cm -1 , giving −21.470 cm -1 . As said above, the gas-phase BF 3 ·Ar complexation shift is an upper limit for the solvent shift induced by an axial argon atom: therefore, the complexation shift in solution must be expected to be somewhat larger than −21.47 cm -1 .…”

“…In a matrix isolation infared study, the symmetric BF 3 stretch of the complex, which is symmetry forbidden in the BF 3 monomer, was not observed: this is in line with the small distortion from planarity of the BF 3 moiety. More recently, high-resolution infrared spectra of the adduct formed in a jet expansion have been discussed, and renewed matrix isolation measurements, combined with ab initio calculations at the 6-31G level, have been performed …”

Van der Waals Complexes between Unsaturated Hydrocarbons and Boron Trifluoride: An Infrared and ab Initio Study of Ethene·BF3 and Propene·BF3

“…As a result, BF 3 readily forms stable adducts with electron donors, particularly with nitrogen and oxygen bases. − These adducts have been studied using a variety of techniques. − Under cryogenic conditions also a number of weakly bound complexes have been studied to date. For instance, molecular beam high-resolution infrared spectra of the adduct of BF 3 with Ne, Ar, Kr, N 2 , and CO have been observed by Takami and co-workers, − and similar complexes involving HCN and HCCCN were described by Kerstel et al . Also, the molecular beam microwave spectra of BF 3 complexes with a variety of Lewis bases have been reported, − and the complexes with N 2 , CO, and H 2 O, as well as the BF 3 dimer, have been identified in matrix isolation infrared studies. − …”

“…[4][5][6] Under cryogenic conditions also a number of weakly bound complexes have been studied to date. For instance, molecular beam highresolution infrared spectra of the adduct of BF 3 with Ne, Ar, Kr, N 2 , and CO have been observed by Takami and coworkers, [7][8][9][10][11] and similar complexes involving HCN and HC-CCN were described by Kerstel et al 12 Also, the molecular beam microwave spectra of BF 3 complexes with a variety of Lewis bases have been reported, [13][14][15][16][17][18] and the complexes with N 2 , CO, and H 2 O, as well as the BF 3 dimer, have been identified in matrix isolation infrared studies. [19][20][21][22] For some time, we have been using cryosolutions in the study of van der Waals complexes of BF 3 .…”