Dendrimer-like cyanoruthenate anions with high potential connectivity derived from a [Ru(bpym)3]2+ core

Reaction of [Ru(bpym)3]2+ (bpym = 2,2′-bipyridmidine) with hexacyanoruthenate under forcing conditions affords a mixture of the trinuclear species [(bpym)Ru{(µ-bpym)Ru(CN)4}2]2−, [1]2−, and the tetranuclear species [Ru{(µ-bpym)Ru(CN)4}3]4−, [2]4−, in which two or three (respectively) of the peripheral vacant bpym binding sites of [Ru(bpym)3]2+ are occupied by {Ru(CN)4}2− fragments. Thus, [1]2− and [2]4− have eight and twelve externally-directed cyanide groups respectively for use in forming high connectivity coordination networks. The crystal structure of HK[1]·2MeOH·6.5H2O reveals a one-dimensional ladder structure in which [1]2− anions are connected by (i) cyanide/K+ and (ii) bpym/K+ coordination interactions.

Graphical AbstractReaction of [Ru(bpym)3]2+ (bpym = 2,2′-bipyrimidine) with K4Ru(CN)6 results in the attachment of {Ru(CN)4}2− fragments at two or three of the peripheral vacant diimine sites, giving trinuclear [1]2− (with eight externally-directed cyanide ligands) and tetranuclear [2]4− (with 12 externally-directed cyanides in a D3 symmetric array). These are interesting building blocks for crystal engineering applications providing potentially very high connectivity at a single node in cyanide-bridged networks.Figure optionsDownload as PowerPoint slide