Quantum dynamics of ClH2O- photodetachment: Isotope effect and impact of anion vibrational excitation

Discrete Oligomers and Polymers of Chloride Monohydrate Can Form in Encapsulated Environments: Structures and Infrared Spectra of [Cl4 (H2 O)4 ]4- and {[Cl(H2 O)]- }∞

A discrete tetrachloride tetrahydrate cluster, [Cl₄ (H₂ O)₄ ]^4- , was obtained with a partially-fluorinated triaminocyclopropenium cation, [C₃ (N(CH₂ CF₃ )₂ )(NEt₂ )(NPr₂ )]⁺ . The cluster consists of a [Cl₂ (H₂ O)₂ ]^2- square with each Cl^- coordinated by another H₂ O bridged to another Cl^- . A 1D polymer of chloride monohydrate, {[Cl(H₂ O)]^- }_∞ , was obtained with [C₃ (N(CH₂ CF₃ )₂ )₂ (NBuMe)]⁺ . The tetrameric and polymeric structures were found to be computationally-unstable in the gas phase which indicates that an encapsulated environment is essential for their isolation. DFT and DFTB calculations were carried out on gas-phase [Cl₄ (H₂ O)₄ ]^4- to assist the infrared assignments. Anharmonically-corrected B3LYP transition frequencies were in close agreement with experiment, but DFTB models were only appropriate for qualitative interpretation. Solid-state DFTB calculations allowed the vibrational modes to be assigned. The results found are consistent with "discrete" chloride hydrates.

A Series of Discrete Dichloride Dihydrates: Characterisation and Symmetry Effects

A series of three discrete dichloride dihydrates [Cl₂ (H₂ O)₂ ]^2- have been isolated with different triaminocyclopropenium (TAC) cations and with different crystallographic symmetries. The cluster exhibits D_2h symmetry with the tris(dimethylamino)cyclopropenium cation [C₃ (NMe₂ )₃ ]⁺ , C_2h symmetry with the fluorinated cation [C₃ (N(CH₂ CF₃ )₂ )(NBu₂ )₂ ]⁺ (containing two 2,2,2-trifluoroethyl substituents) and C_2v symmetry with the more fluorinated [C₃ (N(CH₂ CF₃ )₂ )₂ (NBu₂ )]⁺ cation. The effect of symmetry on the infrared spectra of the dichloride ion-pair clusters, as well as deuterated analogues, has been investigated. The D_2h - and C_2h -symmetric clusters each exhibit two stretching bands in the infrared at 3427 and 3368 cm^-1 for D_2h symmetry and 3444 and 3392 cm^-1 for C_2h symmetry, whereas the C_2v -symmetric cluster exhibits three bands at 3475, 3426 and 3373 cm^-1 . Computational studies were carried out on a [Cl₂ (H₂ O)₂ ]^2- cluster with C_2v symmetry to aid the infrared band assignments.

One water to bind a chloride-chloride ion pair: isolation of discrete [Cl2(H2O)]2- in the solid state

A discrete dichloride ion pair in the form of a monohydrate, [Cl₂(H₂O)]^2-, was isolated using the triaminocyclopropenium cation [C₃(NHex₂)(N(CH₂CF₃)₂)₂]⁺. Although this ion pair is calculated to be unstable in the gas phase, the ionic lattice and weak CH-Cl hydrogen bonds assist the stabilization of the cluster. The D₂O and HDO isotopomers were also prepared and characterized.

A Discrete Dichloride Tetrahydrate Trapped by a Cyclopropenium Cation: Structure and Spectroscopic Properties

A discrete dichloride tetrahydrate cluster, [Cl₂ (H₂ O)₄ ]^2- , was obtained as a salt of the bis(diphenylamino)diethylamino cyclopropenium cation [C₃ (NPh₂ )₂ (NEt₂ )]⁺ and characterized by single-crystal X-ray diffraction and infrared spectroscopy. This chloride-chloride ion-pair cluster consists of a [Cl₂ (H₂ O)₂ ]^2- square with opposite edges bridged by water molecules to give a chair-like structure of the non-hydrogen atoms. The solid-state structure is essentially the same as the calculated gas-phase structure. Infrared spectra were also collected on the deuterium analogue [Cl₂ (D₂ O)₄ ]^2- . Computational studies were carried out on gas-phase [Cl₂ (H₂ O)₄ ]^2- to confirm the infrared band assignments in the solid state. The structure and infrared spectrum are consistent with the discrete nature of the cluster.