Complexes of lanthanide (III) ions with nitrogen donor ligands

Publisher Summary In this chapter, one attempts to present a review giving emphasis to these new fields, and to this end as much material as possible has been subdivided under the headings of the various techniques and types of information. As a result of the chosen subdivision, certain aspects, such as the nature of the metal-to-ligand bonding are discussed in more than one section. Little mention will be made of the analytical uses of these ligands, which have recently been reviewed separately (711), of the synthesis of ring-substituted derivatives of the parent ligands, although a potentially useful method using transition-metal complexes has been reported; or of related species, such as 4,4‘-bipyridyl. The coverage of the literature is complete up to the end of 1967, and usually to the end of April 1968, and although many publications have regretfully not been mentioned, one have attempted to discuss the great majority of those papers which one believe to be of special importance.

The Chemistry of Complexes Containing 2,2′-Bipyridyl, 1, 10-Phenanthroline, or 2,2′,6′,2”-Terpyridyl as Ligands

Lanthanide complexes—IV: Complexes of triphenylphosphine oxide with lanthanide and yttrium nitrates

The reactions of potentially hexadentate H2bbpen (N,N'-bis(2-hydroxybenzyl)-N,N'-bis(2-pyridylmethyl)-ethylenediamine, H2L1), H2(Cl)bbpen (N,N'-bis(5-chloro-2-hydroxybenzyl)-N,N'-bis(2-pyridylmethyl)ethylenediamine, H2L2), and H2(Br)bbpen (N,N'-bis(5-bromo-2-hydroxybenzyl)-N,N'-bis(2-pyridylmethyl)ethylenediamine, H2L3) with Ln(III) ions in the presence of a base in methanol resulted in three types of complexes: neutral mononuclear ([LnL(NO3)]), monocationic dinuclear ([Ln2L2(NO3)]+), and monocationic trinuclear ([Ln3L2(X)n(CH3OH)]+), where X = bridging (CH3COO-) and bidentate ligands (NO3-, CH3COO-, ClO4-) and n is 4. The formation of a complex depends on the base (hydroxide or acetate) and the size of the respective Ln(III) ion. All complexes were characterized by infrared spectroscopy, mass spectrometry, and elemental analyses; in some cases, X-ray diffraction studies were also performed. The structures of the neutral mononuclear [Yb(L1)(NO3)], dinuclear [Pr2(L1)2(NO3)(H2O)]NO3.CH3OH and [Gd2(L1)2(NO3)]NO3.CH3OH.3H2O, and trinuclear [Gd3(L3)2(CH3COO)4(CH3OH)]ClO4.5CH3OH and [Sm3(L1)2(CH3COO)2(NO3)2(CH3OH)]NO3.CH3OH.3.65H2O were solved by X-ray crystallography. The [LnL(NO3)] or [Ln2L2(NO3)]+ complexes could be converted to [Ln3L2(X)n(CH3OH)]+ complexes by the addition of 1 equiv of a Ln(III) salt and 2-3 equiv of sodium acetate in methanol. The trinuclear complexes were found to be the most stable of the three types, which was evident from the presence of the intact monocationic high molecular weight parent peaks ([Ln3L2(X)n]+) in the mass spectra of all the trinuclear complexes and from the ease of conversion from the mononuclear or dinuclear to the trinuclear species. The incompatibility of the ligand denticity with the coordination requirements of the Ln(III) ions was proven to be a useful tool in the construction of multinuclear Ln(III) metal ion arrays.

F.P. Laming

Papers

Lanthanide complexes—III: Complexes of 2,2′-dipyridyl with lanthanide chlorides, thiocyanates, acetates and nitrates☆

Lanthanide complexes—II: Complexes of 1:10-phenanthroline with lanthanide acetates and nitrates☆