N. Shintani et al., STUDIES ON MIXED CHELATES .22. 5-COORDINATE COPPER(II) CHELATES WITH N,N,N',N'',N''-PENTAMETHYLDIETHYLENETRIAMINE AND BETA-DIKETONATES, Bulletin of the Chemical Society of Japan, 67(7), 1994, pp. 1828-1834
Mixed Cu(II) chelates with N,N,N',N'',N''-pentamethyldiethylenetriamin
e (pmdt) and five beta-diketonate (dike) ligands, i.e., dipivaloylmeth
anate (dipm), acetylacetonate (acac), pivaloyltrifluoroacetonate (pfac
). tri-fluoro- and hexafluoroacetylacetonate (tfac and hfac, respectiv
ely), were prepared and studied. Their general formula, [Cu(dike)(pmdt
)]ClO4, suggests that they are five-coordinated; X-ray crystal analyse
s confirmed that the chelates with acac and tfac are distorted square
pyramidal, with the axial site occupied by one of the 0 atoms of dike.
Similar structures are presumed for the remaining chelates on the bas
is of spectral similarities. In solutions, these five-coordinated chel
ates are solvated to various extents, showing a characteristic solvato
chromism.