Dfhd complexes

Further substitution of fluorine atoms in the -diketone side chains has led to the synthesis and characterization of the Ln(dfhd)s complexes as NMR shift reagents. Although the hydrated Ln(fod)3 complexes are more soluble in chloroform than the hydrated Ln(dfhd)3 complexes, the lanthanide dfhd complexes have superior solubility in dioxane and aceto-... 

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%). 

An extension of this research led to the preparation of fluorinated )3-diketones which form stable and even more volatile rare earth complexes. Detailed studies of the Ln(thd)3 (I), Ln(fod)3 (12), and Ln(dfhd)3 (13, 14) complexes revealed that the volatility of the tris complex is directly proportional to the degree of fluorine substitution and... 

The increased Lewis acidity of the Ln(dfhd)3 complexes relative to the thd and the fod compounds is demonstrated by a comparison of the induced shifts in CDCI3 solutions of such weak bases as acetonitrile, nitromethane, and anisole (Table III). The induced shifts are for the methyl protons of each compound. Although Pr(dfhd)3 and Yb(dfhd)3 induce the largest shifts, line broadening is appreciable in fact, in experi-... 

Relative to either the Ln(thd)3 or the Ln(fod)3 chelates, use of the Ln(dfhd)3 complexes offers an additional advantage since the )8-diketone... 

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