Planas, J.G., Vinas, C., Teixidor, F., Light, M.E. and Hursthouse, M.B.
Polymorphism and phase transformations in cobaltacarborane molecular crystals
CrystEngComm, 9, (10), . (doi:10.1039/b704833e).
Full text not available from this repository.
The full study of polymorphism in the cobaltacarborane closo-[3-Co(5-C5H5)-1,2-C2B9H11] ( 1) compound by a combination of X-ray diffraction, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), IR and hot-stage microscopy (HSM) is reported for the first time. The previously reported Form I (orthorhombic Form, noncentrosymmetric space group P21212) crystallizes as dark yellow to orange flat prisms from polar dichloromethane. A new centrosymmetric modification (Form II) that crystallizes from a mixture of polar and non-polar solvents has been found. Form II crystallizes as pleochroic orange blocks in the monoclinic crystal system and space group P21/c. Phase transformation between both polymorphs has been observed by DSC, IR and HSM, showing that the centrosymmetric Form II (kinetic) converts irreversibly to the noncentrosymmetric Form I (thermodynamic).
Actions (login required)