Correlation of Dative Bond Length and Donor Proton Affinity in Adducts of SO3: A Good Predictor for HCCCN–SO3

Microwave spectrum of (CH3)3CCN–SO3

“…Complexes of the strong acid SO 3 with nitrogen donors have provided a convenient venue for these studies and we have shown that a variety of physical properties such as N-S bond length, out-of-plane distortion of the SO 3 , binding energy, and electron transfer can be correlated with the energy gap between the donor and acceptor orbitals involved in the interaction [3]. Further work has demonstrated that the proton affinity of the donor, which serves as a readily available measure of its basicity, is also a useful parameter for correlating trends in physical properties [4]. In this note, we report the microwave spectrum of the complex (CH 3 ) 3 CCN-SO 3 and further demonstrate the utility of proton affinity for predicting the properties of partially bound systems.…”

“…The terms involving v and c provide relatively small corrections to the hM s R 2 cm i term and account for large amplitude angular vibrations of the subunits. As in previous work [4,8], values of hcos 2 vi and hcos 2 ci are not well known in this system [24] but reasonable bounds can be assumed. Specifically, the effective value of v eff cos À1 (hcos 2 vi 1/2 ) is taken to lie between the minimum possible value of zero and the 15.6°value determined for Ar-33 SO 3 [25].…”

“…As with other Base-SO 3 complexes, (CH 3 ) 3 CCN and SO 3 were separately introduced into the supersonic expansion, thus limiting the mixing time and suppressing solid formation [4,[6][7][8]. Argon carrier gas was passed over a sample of solid polymerized SO 3 and the resulting seeded gas mixture was expanded at a stagnation pressure of 2.2 atm through a 0.8 mm nozzle, with a repetition rate of 5 Hz.…”

Microsolvation of a partially bonded complex by non-polar and weakly polar microsolvents: a microwave and ab initio study of HCN–SO3–Ar and HCN–SO3–CO

“…The effect of a local environment on partially bonded Lewis acid-base complexes has been a topic of interest in our laboratory for a number of years [1][2][3][4][5][6][7][8][9][10][11][12][13]. Such systems have been shown to exhibit large differences in structure between the gas phase and solid state, and in doing so, reveal an unusual hypersensitivity to nearneighbour interactions.…”