A Single-Crystal Model for MgCl₂–Electron Donor Support Materials: [Mg₃Cl₅(THF)₄Bu]₂ (Bu = n‑Butyl)

The influence of the electron donor tetrahydrofuran (THF) on the formation of the crystalline morphology of MgCl₂ was studied. MgCl₂ was synthesized from magnesium and 1-chlorobutane in the presence of THF with the THF/Mg molar ratio ranging from 0.063 to 2.0. With the highest amounts of THF crystalline particles were formed, as evidenced from scanning electron microscopy images. The X-ray structure analysis of these single crystals revealed the new organometallic Mg compound [Mg₃Cl₅(THF)₄Bu]₂ (Bu = n-butyl), which has an open dicubane-like structure with four octahedrally and two tetrahedrally coordinated Mg atoms. The compound also contains two butyl groups directly bound to the Mg atoms at the opposite corners of the dicubane structure. With the lowest THF amounts, structurally disordered MgCl₂/THF complexes were formed. The transition from single crystals toward particles with an amorphous morphology appeared to occur through an intermediate type of morphology with a three-dimensional network structure. The network structure is formed from a thin (30–100 nm) fiberlike MgCl₂/THF material. Infrared and solid-state ¹³C nuclear magnetic resonance spectroscopy measurements revealed different types of Mg sites present in the MgCl₂/THF complexes.