Ten‐Coordinate Neodymium(III) Complexes with Triethylenetetraaminehexaacetic Acid

Stereochemistry of Compounds with Coordination Number Ten

“…The former is found in a neodymium compound with an approximately bicapped square antiprismatic coordination sphere. [45] A decadentate ligand composed of a hexadentate macrocyclic ring with two pending chelating units (13) also adapts reasonably to the BCSAPR geometry in its La, Ce, and Pr complexes (shape measures of 2.07-4.33, see the Supporting Information).…”

Structure, Dynamics, and Computational Studies of Lanthanide‐Based Contrast Agents

“…In the crystal structures of larger Ln 3+ ions (La 3+ → Nd 3+ ) [231][232][233][234][235][236], the Ln 3+ ion is usually coordinated in a decadentate fashion through the four N-atoms and six carboxylate O-atoms in a distorted bicapped square antiprismatic coordination polyhedron with the terminal N-atoms at the capping positions. However, the complexes of smaller Ln 3+ ions (Sm 3+ → Yb 3+ ) [231,233,[237][238][239][240][241] show nine-fold coordination with the TTHA ligand in a distorted TTP or monocapped-SA geometry; a terminal carboxylate remains uncoordinated.…”

“…Comparison of electronic absorption spectra for the solid state with those for solutions has shown that the structures of the Ln-TTHA complexes are similar in these media [234,235,238]. These spectra, luminescence spectra, and NMRD have shown that in addition binuclear structures occur in solution, particularly in acidic medium [171,242,243].…”

Relationships Between Structure and Spectroscopic Properties of Nd3+ Ethylene­diaminetetramethylenephosphonates and Ethylenediaminetetraacetates

“…Although there are also f-f transitions above 950 nm in the spectra of the Nd 3+ ions, their intensities are not included as the 4 I 9/2 Ǟ 4 I 15/2 and 4 I 9/2 Ǟ 4 I 13/2 bands are superimposed with overtone and/or combination bands from organic ligands and H 2 O molecules. [25,26] The intensity of the hypersensitive transition 4 I 9/2 Ǟ 4 G 5/2 , 2 G 7/2 is particularly affected by variations in the immediate environment of the Nd 3+ ion; therefore, resemblance of the band shapes may reflect similar coordination environments of the Nd 3+ ions. Moreover, the oscillator strengths of the most intense bands ( 4 I 9/2 Ǟ 4 G 5/2 , 2 G 7/2 , 4 I 9/2 Ǟ 4 F 7/2 , 4 S 3/2 and 4 I 9/2 Ǟ 4 F 5/2 , 2 H 9/2 ) are reduced more drastically in I and III than in II and IV.…”