DISTORTIONS OF MOLECULAR-GEOMETRY IN PENTAFLUOROPHENYL RINGS BONDED TO METALS

The variance in the geometry of pentafluorophenyl rings bonded to meta ls of the fourth, fifth and sixth rows of the Periodic Table has been analyzed from the data present in the literature. The application of u nivariate and bivariate analysis to internal coordinates shows that th e major variation corresponds to bond angles, specially to those near to the substitution. This effect (''ipso'' effect) seems to be related to the Pauling's electronegativity of the metals. Multivariate analys is of these coordinates reveals the existence of three principle effec ts, the main one of them corresponding to the ''ipso'' effect and the other two being related with the thermal vibration of the molecule and with the inhomogeneity of the sample. The application of bivariate an alysis to symmetry coordinates does not give any correlation between t he two orthogonal components describing fully the angular variance.