MOLECULAR QUADRUPOLE MOMENTS, MAGNETIC ANISOTROPIES, AND CHARGE DISTRIBUTIONS OF FERROCENE AND RUTHENOCENE.

Article abstract of DOI:10.1021/ja00354a006

Measurements of the infinite-dilution molar Kerr constants, field-gradient birefringence constants, and Cotton-Mouton constants of ferrocene and ruthenocene as solutes in cyclohexane at 25 degree C are reported. The observations yield the effective polarizability anisotropy, the electric quadrupole moment, and the magnetic anisotropy of each molecule. Analysis of these properties shows that ferrocene and ruthenocene are more polarizable in directions parallel, rather than perpendicular, to the ligand-metal-ligand axes; it suggests that the bonding results in transfer of electronic charge from the metal atom toward the cyclopentadienyl rings; and it enables the observed magnetic anisotropies to be separated into oppositely signed diamagnetic and temperature-independent paramagnetic contributions. A useful new synthesis of ruthenocene is described.