White Light Emissive DyIII Single-Molecule Magnets Sensitized by Diamagnetic [CoIII(CN)6]3- Linkers

The self-assembly of Dy-III-3-hydroxypyridine (3-OHpy) complexes with hexacyanidocobaltate(III) anions in water produces cyanido-bridged {[Dy-III(3-OHpy)(2)(H2O)(4)] [Co-III(CN)(6)]}center dot H2O (1) chains. They reveal a single-molecule magnet (SMM) behavior with a large zero direct current (dc) field energy barrier, Delta E=266(12) cm(-1) (approximate to 385 K), originating from the single-ion property of eight-coordinated Dy-III of an elongated dodecahedral geometry, which are embedded with diamagnetic [Co-III(CN)(6)](3-) ions into zig-zag coordination chains. The SMM character is enhanced by the external dc magnetic field, which results in the Delta E of 320(23) cm(-1) (approximate to 460 K) at H-dc = 1 kOe, and the opening of a butterfly hysteresis loop below 6 K. Complex 1 exhibits white Dy-III-based emission realized by energy transfer from Co-III and 3-OHpy to Dy-III. Low temperature emission spectra were correlated with SMM property giving the estimation of the zero field Delta E. 1 is a unique example of bifunctional magneto-luminescent material combining white emission and slow magnetic relaxation with a large energy barrier, both controlled by rich structural and electronic interplay between Dy-III, 3-OHpy, and [Co-III(CN)(6)](3-).