Polymers diketonate ligands

Another way to introduce Ir(III) complexes into the main-chain of polyfluorenes was realized by Suzuki polycondensation of fluorene segments and /3-diketone ligand chelated with Ir(III) chloride-bridged dimmer (polymer 26 and 27) [34,35]. A saturated red-emitting polymer light-emitting diode was achieved from the device ITO/PEDOT/polymer 27 + PBD (40%)/Ba/Al with the maximum external quantum efficiency of 0.6% at the current density (J) of 38.5 mA/cm2 and the maximum luminance of 541 cd/m2 at 15.8 V. 

It would be worthwhile to follow up and optimize the capability of LLCs entrapped in polymer matrices for the indication of humidity in the gas phase. This approach seems promising since it was shown that the luminescence of EuCls included in a dehydrated Nafion membrane is quenched in the course of adsorption of water vapor [108]. A series of p-diketonate complexes of Eu " (28 A-C in Scheme 5) embedded in Nafion membranes were also evaluated for their responses to relative humidity [109]. There still remains some analytical work to be done because astonishingly it depends on the type of p-diketonate ligand whether the luminescence is suppressed or enhanced in presence of water. 

Several other orders of decreasing thermal stability for metal chelate polymers derived from a variety of bis(jS-diketone) ligands have been published. 

The kinetics of ligand exchange between [M(dik)4] (M = Zr or Hf dik = acac or tfacac) and the corresponding free /3-diketones have been studied by Adams and Larsen.233 [Zr(acac)4] exchanges ligands with a polystyrene resin functionalized with acetylacetonate groups to give a polymer-bound zirconium complex.234... 

The intra-complex PCMU are those compounds in which at least one fragment is linked with the metal ion via both a valent and coordination bond. It should be noted that such compounds can be neutral, cationic, anionic or contain, in addition to chelating ligands, monofunctional varieties. The number of such PCMU is enormous therefore we shall indicate the most frequent types. A detailed consideration has been given earlier to complexes of metals with polymers containing diketone [13], o-hydroxyazomethine [14], enaminoketone [15], amino add [16], 8-hydroxyquinoline [17] and other groups. 

The compound [Ca(hfac)2(H20)2]2153 (Fig. 38) is a centrosymmetric dimer in the solid state, while the analogous barium complex, [Ba(hfac)2 (H20)]x,153 exists as a polymer. Both compounds have M-F interactions similar to those described for [Ba2(hfac)4(Et20)L The smaller size of calcium is probably responsible for the structural differences between these two water adducts. The volatility of these fluorinated complexes is certainly decreased by the M-F interactions, as well as by the overall oligomeric structure of the compounds. What relationship metal ligand interactions of this type play in the incorporation of BaF2 in films prepared from these compounds has not yet been elucidated. Interestingly, no base-free fluorinated /3-diketonate compounds have been structurally characterized. 

Acetylacetonate is usually considered the reference ligand for the fi-diketonates and it has been comprehensively studied. Neutral ligand compounds are known acacH acts as a unidentate ligand on an (MnBr2) linear polymer, like (8), and it chelates in [Mn(acacH)3] InCl4]2.286 A related ligand diamidomalonate has been proven to Chelate in [Mn(N03)2L2], which has bidentate amide and unidentate nitrates.289... 

Scheme 1 represents the synthesis of a linear coordination polymer by use of bischeiating ligands such as rubeanic acid, bis-1,3-diketones, and bis-8-hydroxyquinolines which can be attached simultaneously to metal atoms or ions. Equation 6 describes a recent example of the coordination polymers which is prepared according to Scheme 113). This field of coordination polymers was developed from the large research program in USA during the Second World War in attempts to find thermally stable polymers. The activity in this field has been recently increased in the expecta-...

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