Syntheses, structural determination, and binding studies of nine-coordinate mononuclear complexes (EnH₂)₃[Eu^III(Etha)]₂ · 11H₂O and (EnH₂)[Eu^III(Egta)(H₂O)]₂ · 6H₂O

Two novel ethylenediaminium salt of europium complexes with aminopolycarboxylic acid ligands, (EnH(2))(3)[Eu-III(Ttha)](2) center dot 11H(2)O (I) (En is ethylenediamine, H(6)Ttha is triethylenetetramine-N,N,N',NaEuro(3),NaEuro ',NaEuro '-hexaacetic acid) and (EnH(2))[Eu-III(Egta)(H2O)](2) center dot 6H(2)O (II) (H(4)Egta is ethyleneglycol-bis(2-aminoethylether)-N,N,N',N'-tetraacetic acid) complexes were synthesized, and their crystal structures were determined by single-crystal X-ray diffraction techniques. Both of the two complexes adopt nine-coordinate structures with the pseudo-monocapped square antiprism and crystallize in the monoclinic crystal system with the P2(1)/n space group. The crystal data for complex I are as follows: a = 17.8262(8), b = 19.3137(5), c = 20.6233(8) , beta = 111.301(2)A degrees, V = 6615.3(4) (3), Z = 8, rho (c) = 1.677 mg/m(3), mu = 1.981 mm(-1), F(000) = 3432, R = 0.0308, and wR = 0.0737 for 43622 observed reflections with I a parts per thousand yen 2 sigma(I). The crystal data for complex II are as follows: a = 12.952(3), b = 12.618(2), c = 14.809(3) , beta = 105.695(2)A degrees, V = 2330.0(8) (3), Z = 4, rho (c) = 1.800 mg/m(3), mu = 2.765 mm(-1), F(000) = 1276, R = 0.0297, and wR = 0.0638 for 18416 observed reflections with I a parts per thousand yen 2 sigma(I). One remarkable feature of the two complexes is that the protonated [EnH (2) (2+) ] cations conjugating to [Eu-III(Ttha)] (2) (6-) and [Eu-III(Egta)(H2O)] (2) (2-) complex anions are reviewed, respectively, which open the path for the Eu-III complexes conjugating with other various biomolecules.