The Structure of CCl₅^– in the Gas Phase

Abstract

The first experimental evidence of the structure of the CCl 5 − gas-phase anion complex is presented in conjunction with results from high-level theoretical calculations. The photoelectron spectrum of the system shows a single peak with a maximum at 4.22 eV. Coupled cluster single double (triple) detachment energies of two stable C 3v ion−molecule complexes of the form Cl − •••CCl 4 were also determined. The first complex found features the Cl − bound linearly in a Cl − •••Cl−C bonding arrangement, while the second, less stable minimum has the Cl − positioned at the face of the CCl 4 molecule, midway between three chlorine atoms. The calculated detachment energy for the first complex was found to be in excellent agreement with experiment, allowing the structure of CCl 5 − in the gas phase to be postulated as a noncovalent Cl − •••CCl 4 anion complex, with the Cl − anion tethered by a typical halogen bond.

Spectroscopic Investigation of Chalcogen Bonding: Halide–Carbon Disulfide Complexes

“…The 2 P 3/2 photodetachment peak of chlorine occurs at approximately 3.61 eV, [23,24] and upon complexation with nitrogen, this electron binding energy shifts to 3.72 eV [25] . When the complex partner is changed from nitrogen to tetrachloromethane, the 2 P 3/2 electron binding energy shifts to approximately 4.22 eV [26] . The difference between the electron binding energy of the bare chloride anion and that of the complex is referred to as electron stabilisation energy (E stab ) and serves as a measure of the strength associated with the stabilising interaction(s) involved in complex formation.…”

“…The combination of anion photoelectron spectroscopy and theoretical chemistry predictions has previously been utilised to investigate halogen bonding [26,28,29] . In this paper, we present an anion photoelectron spectroscopic study of the chalcogen binding motif involved in stabilising dimer complexes of halides and carbon disulfide.…”

Towards an Understanding of Halide Interactions with the Carbonyl‐Containing Molecule CH3CHO

“…This solvent shift is largely dependent on the strength of the interaction between the halide anion and complexing neutral molecule [7] . Our group has recently combined anion photoelectron spectroscopy and CCSD(T) calculations to probe the electronic structure of systems involving halogen bonding, [8] as well as ion‐radical [9] and ion‐multipole [10] interactions.…”

“…While the stability of the anion complex ( D 0 ) has been established as an indicator of electron stabilisation ( E stab ) previously, [8–10] some effect on the neutral Franck‐Condon surface may be resulting in a lower E stab than expected for I − ⋅⋅⋅CH 3 CHO. Another way to delve further is to compare the predicted 2 P 3/2 detachment energies of I − ⋅⋅⋅CH 2 O from previous work and that of I − ⋅⋅⋅CH 3 CHO reported here, in order to ascertain if the theory is consistent with the experimental observation.…”

Photoelectron Spectroscopy and Structures of X−⋅⋅⋅CH2O (X=F, Cl, Br, I) Complexes

“…Recently, our group has utilised anion PES in conjunction with ab initio calculations to determine the electronic structure of anion‐molecule complexes, and in particular, the halide‐acetone complexes provide a useful comparative dataset for this work [29,30] . Higher resolution techniques, such as anion zero electron kinetic energy (ZEKE) spectroscopy and slow electron velocity imaging (SEVI) can be used to not only determine eBEs, but also to provide vibrational elucidation of the neutral atom‐molecule complex.…”