Volatility studies of metal chelates. III. Thermal and gas chromatographic properties of the volatile copper(II) and nickel(II) chelates of the isomeric tetradentate β-keto enamines formed in the reaction of 1,1,1-Trifluoro-5,5-dimethylhexane-2,4-dione with Ethane-1,2-diamine
The Schiff base, 6,6,6,6',6',6'-hexafluoro-2,2,2',2'-tetramethyl-5,5'-(ethane-1,2-diyldiimino)bis(hex-4-en-3-one), as normally prepared by the condensation of 1,1,1-trifluoro-5,5-dimethylhexane-2,4-dioneand ethane-1,2-diamine is only one of two isomeric forms which give distinct isomers with copper(II)and nickel(II), readily separated on columns of silica gel. The isomeric chelates have large volatility differences and display greater volatility than other tetradentate β- keto enamine complexes. The excellent gas chromatographic behaviour of the chelates leads to detection limits of about 2 picograms metal with the electron-capture detector.