Cubic Three-Dimensional Networks of the Cyanometalate [Fe(CN)₆]^3– with the Ditopic Halogen Bond Donor Diiodoacetylene C₂I₂

Abstract

Halogen-bonded networks have been prepared by cocrystallization of the linear ditopic halogen bond donor diiodoacetylene C2I2 and lipophilic phosphonium salts of the octahedral hexatopic halogen bond acceptor hexacyanoferrate­(III) [Fe­(CN)6]3–. The crystal structure of [PPh3Me]3[Fe­(CN)6]­·3C2I2·7.5MeCN displays a two-fold interpenetrated, three-dimensional cubic halogen-bonded network, in which the CN···I angles are almost linear (170.4(4) and 167.6(4)°). In the case of [PPh4]3[Fe­(CN)6]­·4C2I2·6CH3CN, a two-dimensional ribbon structure with mono- and bifurcated acceptor sites is observed, while [PNP]3[Fe­(CN)6]­·4C2I2·4CH2Cl2 displays a three-dimensional halogen-bonded network structure. In the latter two structures, CN···I angles are in the range of 99.2(6)–161.8(6)° and 118.9(2)–143.1(2)°, respectively. This finding illustrates the high structural flexibility of C2I2 coordination to cyanide ligands, which is supposed to be a consequence of packing effects.

Structural diversity of supramolecular networks formed between polycyanometalates and sulfur-based chalcogen bond donors

“…9,22 Polycyanometalates are attractive building blocks for complex supramolecular structures as they are highly charged anions with exceptional nucleophilic properties and variable topologies. 23 They have successfully been implemented to achieve three dimensional arrays using hydrogen-bonding 24 or halogen-bonding, 25,26 with different organic electrophiles.…”