Connecting Visible Photoluminescence and Slow Magnetic Relaxation in Dysprosium(III) Octacyanidorhenate(V) Helices.

Functional crystalline materials based on bimetallic cyanido-bridged {[DyIII(4-Mephen)(dmf)4][MV(CN)8]}·0.5H2O (M = Re, 1; Mo, 2; W, 3; 4-Mephen = 4-methyl-1,10-phenanthroline) helices have been prepared. 1 is the first heterometallic coordination polymer incorporating an unexplored [ReV(CN)8]3- ion. Implementation of the ReV-based diamagnetic analogue of broadly investigated paramagnetic [MoV(CN)8]3- and [WV(CN)8]3- ions into the d-f coordination framework results in yellow photoluminescence originating from 4F9/2 → 6H J f-f electronic transitions of DyIII sensitized by 4-Mephen, and field-induced slow magnetic relaxation related to the single-ion anisotropy of the dysprosium(III) complexes. We prove that [ReV(CN)8]3- can work as a noninnocent metalloligand in the preparation of emissive 4f-metal-based single-molecule magnets.