Other Lanthanide Complexes

In 2007, the new dysprosium complex Dy(PM)3(TP)2 [PM= l-phenyl-3-methyl-4-isobutyryl-5-pyrazolone and TP = triphenyl phosphine oxide] was reported. A series of devices with various structures were fabricated to investigate the EL performance of Dy(PM)3(TP)2. The best device with the structure ITO/CuPc (15 nm)/Dy complex (70 nm)/BCP (20 nm)/AlQ (30 nm)/LiF (1 nm)/Al (100 nm) exhibited maximum brightness 524 cd m , current efficiency 0.73cdA and power efficiency 0.161mW The low PL quantum yield (3.5%) of the complex caused poor EL performance [75]. 

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As described in Section 9.1.2.2.3, several lanthanocene alkyls are known to be ethylene polymerization catalysts.221,226-229 Both (188) and (190) have been reported to catalyze the block copolymerization of ethylene with MMA (as well as with other polar monomers including MA, EA and lactones).229 The reaction is only successful if the olefin is polymerized first reversing the order of monomer addition, i.e., polymerizing MMA first, then adding ethylene only affords PMMA homopolymer. In order to keep the PE block soluble the Mn of the prepolymer is restricted to <12,000. Several other lanthanide complexes have also been reported to catalyze the preparation of PE-b-PMMA,474 76 as well as the copolymer of MMA with higher olefins such as 1-hexene.477... 

Several other lanthanide complexes have been tested for ROP activity with varying degrees of success. Some of these are summarized in Table 2. 

The Lu—C cr-bonding distances range from 2.425(15) to 2.501(17) A. These distances are approximately 0.2 A shorter than the corresponding distance for a pentahapto cyclopentadienide lutetium bond as predicted from ionic radii. Coordination about the lutetium atom is a slightly distorted tetrahedron. The formal coordination number of four is extremely low for the lanthanides. The only other lanthanide complex with such a low coordination number is the 3-coordinate compound [Lu N(SiMes)2 3] 131). In both cases, the low coordination number is stabilized by the use of bulky hgands. 

Figure 2 Structure of the cation of [PrCl(temyridyl)(H20)5]Cl2-3H20. The structure of this complex would have been impossible to establish by other means than diffraction, and the same is true for many other lanthanide complexes, owing to the lanthanides great variety of coordination patterns (Reproduced with permission from ref. 165. Copyright,...

Tetrakis(2,2,6,6-tetramethyl-3,5-heptanedionato)cerium(IV) has been found to have antiknock properties for petrol.153 Other lanthanide complexes of the same ligand are also effective and mixtures may be used, especially those rich in cerium.154... 

Trifluoromethane sulfonate salts of lanthanides are used as starting materials for the preparation of other lanthanide complexes instead of perchlorates for safety reasons. 

Although pyridine and other amine-type ligands form adducts with lanthanide diketonates, few other lanthanide complexes have been made. However, the first homoleptic lanthanide ammine complexes, [Yb(NH3)g] [Cu(S4)2] NH3, [Yb(NH3)s] [Ag(S4)2]-2NH3,and[La(NH3)9] [ 0(84)2],have been synthesised by reactions in aqueous ammonia. ... 

Following the initial reports of the anteima effect in lanthanide cryptates, many other lanthanide complexes containing additional chromophoric ligands have been investigated and found to be useful as luminescent labels for biological substrates, and in general as sensors based on luminescent properties [21]. 

Both the synthetic trends and the reactivity of the metal macrocycle complexes considered in this review find some rationalization in the strudural data obtained from X-ray analysis. In the series of complexes containing the six-nitrogen, 18-atom macrocycles with aliphatic side-chains, the macrocydic moiety can flex to a different extent in each metal complex, thus allowing the most favorable metal-donor distance to be achieved for all donor atoms. These favorable metal-donor distances, together with appropriate geometries of the donor atoms and low steric strain, must account for the unique inertness displayed by these metal-macrocycle entities under conditions (dilute aqueous solution, presence of acids, bases and competing ligands) that would cause most other lanthanide complexes to decompose instantly. 

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