Nitrilotris(methylenephosphonic) Complexes of Lanthanides [Na(H2O)x]2[LnIIINa6H(H2O)10{N(CH2PO3)3}2] · nH2O (LnIII = Pr, Nd)

The sodium salts of lanthanide nitrilotris(mehylenephosphonate) complexes [Na(H 2 O) x ] 2 [Ln III Na 6 H(H 2 O) 10 {N(CH 2 PO 3 ) 3 } 2 ] · n H 2 O, where Ln III = Pr ( I ), and Nd ( II ), were prepared, isolated, and studied. The isostructural crystals are monoclinic, space group P 2 1 / c , Z = 2; for complex I , a = 11.8168(7), b = 10.5403(9), c = 19.8094(10) Å, β = 94.232(5)°; for complex II , a = 11.7999(2), b = 10.5495(2), c = 19.7976(3) Å, β = 94.158(2)°. The lanthanide ions are coordinated at the center of a cage consisting of two {N(CH 2 PO 3 ) 3 } acid residues and six sodium ions, which form P–O–Na–O–P bridges. The Ln coordination polyhedron is a regular rhombohedron (CIF files CCDC nos. 1825702 ( I ), 1825700 ( II )).