Stability of lanthanides

Eu(III) complexes of quinolinecarboxylic acids, including 5, were studied (00MI31). Those of complexes of 5 with Eu(III) and Tb(III) ion were studied, and they were applied for analysis of 5 in medicinal preparations (00UKZ115). Stability of lanthanide complexes with 5 was studied (00MI67). The fluorescence spectra of 5 complexed with Co(II) and ATP was measured (01SA(A)1317). 

In particular the redox stability of lanthanide cations makes the route superior to, e.g., the usual metathesis reaction involving lanthanide halides. The advantages are evident ... 

It is clear that both the thermodynamic and spectroscopic approaches agree well with respect to the estimation of redox potentials and stabilities of lanthanides in different oxidation states. 

The thermodynamic stability of lanthanide complexes with inorganic ligands OH- and F increases slightly with increase in atomic number. The formation constants for MOH2+ and MF2+ formation... 

Kremer, C., Torres, J., Dominguezb, S., and Mederos, A. (2005) Structure and thermodynamic stability of lanthanide complexes with amino acids and peptides. Coordination Chemistry Reviews, 249, 567-590. 

Improvement in fractional separations in terms of the var5dng stabilities of lanthanide complex species is a well-known and highly important area of applied chemistry (34) S6). The complex species are often useful in analytical determinations. Certain of them possibly can be applied in constructing amorphous transparent or liquid laser devices. 

The. stability of lanthanide complexes can be increased by means of the chelate eftect, and much early work was directed toward the elucidation of the stability of the lanthanide chelates.- 2 The results are only partially interpretable in terms of simple... 

Most recently, it was discovered in our laboratory that benzamidinate ligands are also capable of stabilizing novel cerium(IV) species. Thus, they belong to the limited number of organic ligands which allow the stabilization of lanthanide complexes in all possible oxidation states (4-2,+3, and +4). In analogy to the reaction shown in Scheme 10, treatment of anhydrous cerium(III) trichloride with... 

Amidopyridinate ligands also lead to the assembly and stabilization of lanthanide hydride clusters. The reaction of [ApR(CH2SiMe3)2(THF)] (R = Y, Lu Ap = (2,6-diisopropylphenyl)[6-(2,4,6-triisopropylphenyl) pyridin-2-yl]aminate) with either PhSiHs or H2 afforded trinuclear alkyl-hydrido clusters [(ApR)3(/i2-H)3(/i3-H)2(CH2SiMe3)(THF)2] (Lyubov et al., 2008). 

The stability of lanthanide hydrides is strongly controlled by steric factors. In particular, the small size of the hydride ion requires the presence of bulky ancillary ligands, usually ethers and/or anionic coligands, in order to prevent the rearrangement to more stable derivatives. 

Structure and thermodynamic stability of lanthanide complexes with amino acids and peptides 05CCR(249)567. 

The closest redox-stable analogue of Ce(IV) is thorium(IV), for which a large data base of thermodynamic parameters is available for the carboxylic add complexes (Martell and Smith 1977). Using the ionic radii of Shannon (1976) and recalling that the stability of lanthanide and actinide complexes is derived almost exclusively from electrostatics, we can estimate that a 16% increase in the log of the stability quotients for thorium (since AG oc Z /r oc log should provide a reasonable estimate for the corresponding complexes of cerium(IV) [rce(CN = 8) = 0.97 A, r iCN = 10) = 1.13 A, (l/rce)/(l/ xh) = 116, CN = coordination number]. 

Fig. 9. Relative stability of lanthanide con lexes with a variety of water soluble chelating agents (1) (R-hiba), (2) P2(R lactate), (3) pjlR-glycolate), (4) (5) Pi(R-dcta), (6) P,(R-edta), (7)...

It is appropriate to consider the relative stability of lanthanide conq)lexes as a first indicator of a ligand s potential applicability for lanthanide separations. In fig. 9 is shown a plot of the relative stability of a variety of lanthanide carboxylate complexes (normalized to log/ (Gd )=0) of importance in ana ical separations. The 1 2 complexes of the lanthanides with glycolate and digjtycolate exhibit similarly poor discrimination of lanthanide ions between Gd and Ho, though the overall slope is greater for diglycolate. The 1 2 lactate complexes vary more regularly than these species, but... 

Dorenbos P (2(K)5) Valence stability of lanthanide ions in intn-ganic compounds. Chem Mater 17 6452... 

Figure 6 A thermochemical cycle to assess the stability of lanthanide dihaUdes with respect to disproportionation...

To evaluate the thermal stability of lanthanide coordination polymers, the author conducted thermogravimetric analyses (TGA) in an argon atmosphere at a heating rate of 1 °C min (Fig. 3.5). Their TGA thermograms revealed that [Eu(hfa)3(dpbp)] and [Tb(hfa)3(dpbp)] have decomposition points of 308 and 317 °C, respectively (Table 3.1). In contrast, the decomposition point of Tb(III)... 

Given the kinetic inertness of low spin tf transition metal complexes, especially with low spin metal ions, our focus wiU be mainly on the kinetic stability of lanthanide chelates and their derivatives described in this chapter. 

Gadolinium anomalies have occasionally been conceptualized as a particular example of the tetrad effect (Masuda and Ikeuchi 1979, Masuda et al. 1987), wherein patterns in lanthanide stability constants are developed in response to enhanced stability of lanthanide 4f shells which are quarter, half and three quarter filled. In the recent analysis by McLennan (1994), the existence of a tetrad effect in natural systems was termed ambiguous. The stability constant analysis of Byrne and Li (1995) provided no prominent... 

Clark DL, Gordon JC, Hay PJ, Poli R (2005) Existence and stability of lanthanide — main group element multiple bonds. New paradigms in the bonding of the 4f elements. A DFT... 

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