Notes. A spectroscopic and crystallographic study of the [ReNCl4]– ion

Abstract

Preparation of [AsPh₄][ReNCl₄] was accomplished by the addition of ReNCl₄ to [AsPh₄]Cl in POCl₃. The crystal structure and the i.r. spectra reveal the nearly ideal C_4v symmetry of the [ReNCl₄]^– ion. The force constant of the ReN bond is in agreement with the observed ReN length of 1.619(10)Å. The Re–Cl bond distance, 2.322(2)Å, is the first to be reported for a Re^VI case. Unit-cell parameters are in close agreement with those of the other members of the isostructural series: a= 12.776(4), c= 7.778(3)Å, Z= 2, and D_c= 1.90 g cm^–3 in the tetragonal space group P4/n. Least-squares refinement gave a final R value of 0.022 for 534 unique observed reflections.