Lanthanide complex with triphenyl

Lanthanide triphenyl complexes have been known for about 40 years. These neutral triphenyl complexes [Ln(C6H5)3(THF) ] are synthesized by a transmetallation reaction of the lanthanide metal with diphenyl mercury or triphenyl bismuth in THF [34]. Recently, it has been reported that metathesis reaction of anhydrous lanthanide trichloride with aryllithium is a more convenient and reproducible method than the transmetallation reaction used previously for the synthesis of triaryl lanthanide complexes. Several lanthanide triphenyl and substituted triphenyl complexes have been synthesized (Equation 8.14) [35]. 

The complexes of monodentate oxygen ligands are less stable than those of chelates and tend to dissociate in aqueous solution the ions associate in aqueous solution with both nitrate and sulfate to give species such as MNOj +, MS04, etc., and anionic carbonate complexes are known. Many crystalline compounds or salts have been obtained from the lanthanide salts in ethanolic solutions (a) with hexamethylphosphoramide,27 which appears to give 6-coordinate species, [M(HMPA)6](C104)3, (b) with triphenyl-... 

We have noted that N-bonded thiocyanate complexes dissociate readily in solution. Mixed ligand complexes of lanthanides with thiocyanates and L = ethanol, pyridine, triphenyl phosphorous oxide, phenanthroline, etc. have been synthesized. 

Lu atom (Lu-N 2.352(4) A). The formation of the dianion complex apparently proceeds by nucleophilic addition of the imido unit to the C N group of benzoni-trile, which demonstrates that a lanthanide-imido bond, even in a bridging form, is very reactive. This is in contrast with what was observed previously for bonds between transition metals and bridging imido ligands, which are usually robust and unreactive. Moreover, the resultant product represented the first metal complex of an amidinate dianion, in contrast to the well-known complexes of various metals with amidinate monoanions [RNC(R0NR] as ligands [6,7]. The dianion complex and related complexes derived from imido lanthanide species react with excess of benzonitrile under selective formation of the cyclotrimerization product 2,4,6-triphenyl-1,3,5-triazine [72]... 

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