A Series of Discrete Dichloride Dihydrates: Characterisation and Symmetry Effects.

A series of three discrete dichloride dihydrates [Cl (H O) ] have been isolated with different triaminocyclopropenium (TAC) cations and with different crystallographic symmetries. The cluster exhibits D symmetry with the tris(dimethylamino)cyclopropenium cation [C (NMe ) ] , C symmetry with the fluorinated cation [C (N(CH CF ) )(NBu ) ] (containing two 2,2,2-trifluoroethyl substituents) and C symmetry with the more fluorinated [C (N(CH CF ) ) (NBu )] 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 - and C -symmetric clusters each exhibit two stretching bands in the infrared at 3427 and 3368 cm for D symmetry and 3444 and 3392 cm for C symmetry, whereas the C -symmetric cluster exhibits three bands at 3475, 3426 and 3373 cm . Computational studies were carried out on a [Cl (H O) ] cluster with C symmetry to aid the infrared band assignments.