Why does {p-Bu~t-calix[4]-(OMe)_2(O)_2ZrCl_2} distort away from C_2v symmetry?

摘要

The distortion away from the C_2v symmetry observed in the X-ray structure of the {p-Bu~t-calix[4]-(OMe)_2(O)_2ZrCl_2} complex is explained with the help of density functional calculations on the Zr(OH)_2(H_2O)_2Cl_2 model system. The distortion is not caused by intermolecular packing effects but rather by the steric constraints imposed upon the O-Zr-O bond angles by the attachment of the oxygen atoms to the calix[4]arene ligand.