STUDIES ON MIXED CHELATES .22. 5-COORDINATE COPPER(II) CHELATES WITH N,N,N',N'',N''-PENTAMETHYLDIETHYLENETRIAMINE AND BETA-DIKETONATES

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.