NEVE-COORDINATE RARE EARTH METAL COMPLEXES WITH AMINOPOLYCARBOXYLIC ACIDS: MONONUCLEAR (NH4)3[Tb~(Ⅲ)(ttha)]·5H2O AND BINUCLEAR (NH4)4[Tb_2~(Ⅲ)(dtpa)2] 9H2O

摘要

The two title coordination compounds, (NH4)3[Tb~(Ⅲ)(ttha)]·5H2O (ttha=triethylenetetramine-N,N,N',N",N'",N'"-hexaacetic acid) and (NH4)4[Tb_2~(Ⅲ)(dtpa)2]·9H2O (dtpa=diethylenetri- amine-N,N,N',N",N"-pentaacetic acid), have been prepared and characterized by FT-IR, ele-mental analyses, TG-DTA and single crystal X-ray diffraction technique. The (MH4)3[Tb~(Ⅲ)(ttha)]·5H2O compound is monoclinic, P2_1/c; a=10.398(1), b=12.791(1), c=23.199(2) A; β=90.914(2)°; V=3084.9(5) A3; Z=4; D_(calc)=1.704 g/cm3; μ(МоК_α)=2.376 mm~(-1); R = 0.023 and wR2 = 0.049 for 5429 observed reflections with Ⅰ>2σ(Ⅰ). The [Tb~(Ⅲ)(ttha)]~(3-) complex anion in the crystal has a nine-coordinate mononuclear molecular structure with pseudo-monocapped square-antiprismatic configuration. The (NH4)4[Tb_2~(Ⅲ)(dtpa)2]·9H2O compound is triclinic, P-1; a=9.739(1), b=10.010(1), c==12.968(2)А; α=85.890(2)°, β=77.338(2)°, γ=77.587(2)°; V=1204.2(2)A3; Z=1; D_(calc)=1.832 g/cm3; μ(МоК_α)=3.015 mm"1; R = 0.024 and wR2=0.060 for 4750 observed reflections with Ⅰ>2σ(Ⅰ). The [Tb_2~(Ⅲ)(dtpa)2]~(4-) complex anion has a binuclear structure in the crystal; the two Tb~(Ⅲ) centers are equivalent and have a nine-coordinate environment with the same pseudo-tricapped trigonal-prismatic configuration. The thermal analysis revealed that the coordination cores of the (NH4)3[Tb~(Ⅲ)(ttha)]·5H2O and (NH4)4[Tb_2~(Ⅲ)(dtpa)2]·9H2O compounds are stable up to 221℃ and 252℃, respectively.