INFRARED AND RAMAN SPECTRA OF SOME 6- 7- AND 8-COORDINATE ACETYLACETONATO COMPLEXES OF ZIRCONIUM(4) AND HAFNIUM(4)

Infrared (4000-70 cm−1) and Raman spectra are reported for six-coordinate dihalobis(acetylacetonato) and seven-coordinate halotris(acetylacetonato) complexes of zirconium(IV) and hafnium(IV), M(acac)2X2 (X = Cl or Br) and M(acac)3X (X = Cl, Br, or, when M = Zr, I). Spectra are also reported for the eight-coordinate acetylacetonato complexes, M(acac)4 (M = Zr, Hf, Ce, or Th). Vibrational frequencies assigned to carbonyl stretching, metal-halogen stretching, and certain of the metal-oxygen stretching modes are sensitive to coordination number. The spectra indicate the cis configuration for the M(acac)2X2 complexes, and they afford confirmatory evidence for the seven-coordinate nature of the M(acac)3X complexes. © 1968, American Chemical Society. All rights reserved.