Mechanistic insights into the gelation of cyanide-bridged coordination polymers

FORTMEYER, IVY C.; HOIJEMBERG, PABLO ARIEL; YAN, YONG; PELCZER, ISTVÁN; BOCARSLY, ANDREW B.

Denver, CO

Conferencia; ACS National Meeting; 2015

American Chemical Society

Cyanogels comprise a novel class of coordination polymers, in which cyanide-bridged gels form spontaneously from a mixture of cyanometalate and halometalate solutions. Prior work on these systems has elucidated the physical properties of these gels and their potential applications for gas storage and catalysis. However, studies on the gelation process itself have been limited. Our current work uses a combination of standard solution-phase NMR and high resolution magic angle spinning (HR-MAS) techniques to explore the kinetics and mechanism of gelation using three different d6 hexacyanometalates (M = Fe(II), Co(III), Ru(II)) and two different d8 tetrachlorometalates (M? = Pd(II), Pt(II)). Addition of a simple organic probe to the gels? aqueous phase has allowed us to follow the physical sol-gel transformation by 1H NMR. Changes in the cyanide shifts in 13C NMR provide information on the chemical cross-linking process. The mechanistic insight gained from these studies allows for the prediction of metal combinations that can be incorporated into cyanogels in the future.