P-diketonate ligands

Replacements of ferrocene-substituted p-diketone ligands, p-dik, in cyclooctadiene-rhodium(I) complexes [Rh(p-dik)(cod)] by 1,10-phenan-throline are characterized by large negative activation entropies, indicating the operation of the expected associative mechanism, although the... 

Maverick. A.W. and Klavetter, F.E. (1984) Cofadal binuclear copper complexes of a bis(P-diketone) ligand. Inorg. Chem., 23, 4129 130. 

However, the lanthanide p-diketonates shown in scheme 4 cannot be used as labels, since there is no active binding group on the p-diketonate ligands and these complexes are not very stable with stability constants in the order of 103-106 only, therefore the complexes dissociate in highly diluted solutions and the luminescence intensity decreases. Recently, three chloro-sulfonylated tetradentate p-diketones were synthesized by Yuan and Matsumoto (1996,1997) and Yuan et al. (1998a, 1998b) (scheme 5). They differ from other p-diketones, because the emission intensity of their Eu3+ complexes is not weakened by the presence of the sulfonyl... 

Recent work by Cole-Hamilton and coworkers has demonstrated that stability and volatility are enhanced by the use of long-chain fluorinated p-diketonate ligands, that is those derived from Hdfhd (6) and Htdfhd (7). The hydrafed bis(/3-diketonate) complexes M(dfhd)2(H20) and M(tdftid)2(H20) were prepared for Cu, Ca, Sr, and Ba and were all found to sublime below 200 °C with weight loss ranging from 85 to 98% (see Table 15). In addition, the anhydrous compound Ba(tdfiid)2 was reported to melt at 196 °C and volatilize at 220 °C with essentially no decomposition (residual mass by TGA ca. 1%). 

Molecular structures of some representative bis(P-diketones) ligands are shown in Figure 2.8. 

Bis(P-diketones) ligands, were proved to be efficient motifs or structural elements for selfassembling highly luminescent metallo-supramolecular lanthanide complexes [53-59] and representative examples (H2L" ) are shown in Figure 2.8. Special attention has also been paid to the use of enantiomerically pure bis-P-diketones ofH2L " [58]. H2L ° in Figure 2.8 was shown to have the ability to form d-f-d molecular magnetic materials [60]. 

Figure 2.9 Molecular structures of some representative dendrimer dendritic P-diketones ligands.

Tanase, S., Viciano-Chumillas, M., Smits, J.M.M., et al. (2009) Copper(II) and lanthanoid(lll) complexes of a new P-diketonate ligand with an appended non-coordinating phenol group. Polyhedron, 28, 457 60. 

Shiga, T., Ohba, M., and Okawa, H. (2004) A series of trinuclear Cu Ln Cu complexes derived from 2,6-di(acetoacetyl)pyridine synthesis, structure, and magnetism. Inorganic Chemistry, 43, 4435 446. Albrecht, M., Schmid, S., Dehn, S., et al. (2007) Diastereoselective formation of luminescent dinuclear lan-thanide(III) helicates with enantiomerically pure tartaric acid derived bis(P-diketonate) ligands. New Journal of Chemistry, 31, 1755-1762. 

Uekawa, M., Miyamoto, Y., Ikeda, H., et al. (1998) Synthesis and properties of europium complexes with P-diketone ligands for orgnic electroluminescent devices. Bulletin of the Chemical Society of Japan, 71,... 

With a 1,10-phenanthroline functionalized P-diketone ligand, Ir2Ln (Ln = Nd 139, Er 140, Yb 141) heterotrinuclear complexes were recently prepared by Bian and Huang and cowork-ers in a stepwise approach [153, 154], in which the Ir(ppy)2 chromophore is chelated by 1,10-phenanthroline and the lanthanide bound to P-diketone and to nitrates. Upon irradiation... 

Figure 3.4. Molecular structure formula of P-diketonate ligand...

It should be noted that very little phase behavior data is available for ligands with CO2. Since p-diketones have been shown to be viable for the supercritical fluid extraction of a variety of metals, ranging from transition metals to lanthanides and actinides, we will focus on this set of compounds. In particular, the goal of this research is to determine the binary phase behavior of several P-diketones with CO2 because the phase behavior of the ligand/C02 systems is necessary for the design of in-situ chelation processes. Table I lists the lUPAC and abbreviated names for the p-diketones investigated here. These particular p-diketone ligands were chosen because they could be obtained commercially and have been used in a number of supercritical fluid extraction studies (1-4). 

The synthesis and the electroluminescence applications of Tb(III)-complexes with oxadiazole-functionalised P-diketonate ligands 233 were reported <01 JA6179>. 

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