SINGLE-CRYSTAL EPR, CL-35, CL-37 AND N-14, N-15 ENDOR AND ESEEM STUDIES ON (PH4AS)[TCVINCL4/TCVOCL4] .1. SINGLE-CRYSTAL EPR ON (PH4AS)[TC14,15NCL4/TCOCL4], AND CRYSTAL-STRUCTURE OF (PH4AS)[TCOCL4]

A single-crystal EPR study of tetraphenylarsoniumtetrachloro nitrido-technetate (VI), (Ph4As) [Tc15NCl4], diamagnetically diluted by the isoelectronic oxotechnetate (V) complex, and the crystal structure of the host complex are reported. (Ph4As) [TcOCl4] crystallizes tetragonal, space group P4/n, Z=2 with a=b= 12.670(1) and c=7.824(1) Å. The anion possesses C4v symmetry. The EPR spectra are typical of an ion with a 4d1 configuration. At low temperatures very complex 35,37Cl and 15N ligand hyperfine patterns are observed. The 99Tc, 35,37Cl and 15N hyperfine data are analyzed to evaluate the electron spin delocalization: 20% of the spin density is localized in mainly the 3p orbitals of the Cl atoms. © 1990.