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.