ORGANOAMIDO-LANTHANOID AND ARYLOXO-LANTHANOIDS .3. PREPARATION AND X-RAY STRUCTURE OF BIS(MU-3,5-DIMETHYLPYRAZOLATO-N-N')BIS(MU-TETRAHYDROFURAN-O)-BIS[BIS(ETA-2-3,5-DIMETHYLPYRAZOLATO-N,N')NEODYMIUM(III)]

Reaction of neodymium metal with bis(pentafluorophenyl)mercury and pyrazole (Hpz) or 3,5-dimethylpyrazole (Hdmpz) in tetrahydrofuran (thf) yields Nd(pz)3 or [Nd(dmpz)3(thf)]2. X-Ray crystallography has shown that [Nd(dmpz)3(thf)]2 [triclinic, space group P1BAR (No. 2), a 11.070(4), b 11.364(3), c 10.867(2) angstrom, alpha 103.00(1), beta 120.78(3) gamma 97.68(2)degrees, R 0.0235, R(w) 0.0247 for 5575 observed reflections] has a novel centrosymmetric dimeric structure. Each neodymium is eight-coordinate (4,4 bicapped trigonal prism) with two terminal chelating dmpz ligands [Nd-N 2.400(2), 2.413(3), 2.422(3), 2.426(3) angstrom], two bridging dmpz ligands [Nd-N 2.509(2), 2.511(2) angstrom], and, unexpectedly, two bridging tetrahydrofuran ligands [Nd-O 2.792(2), 2.757(2) angstrom].