A Study of the High Pressure Electronic Spectrum of a Pseudotetrahedral Cobalt(II) Complex

Several investigators have studied the electronic spectral properties of tetrahedral and pseudotetrahedral cobalt(ll) complexes (1-6). In many of the studies, the near infrared and visible spectral bands were very useful first in distinguishing tetrahedral from other -- usually five and six-coordinate -- geometries and second in establishing the extent of distortion of such complexes from pure tetrahedral geometry (2,3,5). In some instances, it was possible to gain an understanding of the relative d-orbital energies in the pseudotetrahedral complexes (2) by using the structure typically observed in the near infrared spectra. These investigations have been supported by polarized single crystal studies (7,8). This paper reports the results of a study of the high pressure, near infrared and visible spectrum of a pseudotetrahedral cobalt(ll) complex and indicates how such studies may be used to determine in part the relative ordering of d orbitals.