Abstract:
Organic‐inorganic hybrid materials combine an inorganic component with an organic component at the nanoscale, while potentially retaining the properties of both components. In the current study the structural characteristics and magnetic properties of hybrid materials combining cations of saturated primary, secondary and tertiary amines with perchloridocuprate(II) and perbromidocuprate(II) anions, were studied.
The saturated cations of cyclopentylamine, cyclohexylamine, cycloheptylamine, piperazine and 1,4‐diazoniabicyclo[2.2.2]octane were chosen since the series allows for the study of the effect of the cation size, charge and saturation on the hybrid structure and also due to the scarcity of hybrid structures containing these types of saturated cations in the literature.
Perhalocuprate(II) containing hybrid materials exhibit magnetic properties due to the presence of an unpaired electron on the Cu2+ ion. At low temperatures magnetic ordering may occur via magnetic exchange pathways involving the halogeno ligands, forming ferromagnetic or antiferromagnetic materials. Identification of the magnetic exchange pathways by consideration of the crystal structure allows for the selection of a suitable theoretical quantum mechanical model to which the experimental magnetic data can be modelled, to obtain parameters like the exchange constant.
A part of the work describes the preparation of crystals of the family of hybrid materials under investigation, and the experimental techniques employed to study the structural and magnetic characteristics of the materials. The crystal structures of six novel materials are discussed in detail and compared to related structures characterised in this study, or to structures previously reported in the literature, where possible. Magnetic susceptibility data is analysed for four compounds, two of which are novel and two for structures reported previously in the literature.
By considering the novel structures characterised in this study, as well as structures previously reported in the literature, structural trends are identified. The role of saturation of the cation on the structure, as well as the effect of cation charge, is highlighted for related compounds. Robust hydrogen bonding motifs are identified for two sub‐families of structures, namely those containing isolated tetrahalocuprate(II) anions and those containing related polymeric perhalocuprate(II) anions. In addition, the magnetic properties of the family containing polymeric anions are compared.
