Actinide 4,4′‐Bipyridine‐ N , N ′‐Dioxide Coordination Polymers: Cationic Framework Structures Templated by Dicyanoaurate and Tetracyanoaurate Counterions
Sylvain St. Louis, Thomas E. Karpiuk, Daniel B. LeznoffFour new actinide coordination polymers utilizing cyanoaurate anions have been synthesized and characterized by single‐crystal X‐ray diffraction. The use of O‐donor 4,4′‐bipyridine‐ N , N′ ‐dioxide (bipyO 2 ) ligands as neutral supports proved instrumental in the self‐assembly of these frameworks, particularly given the high Lewis acidity of the Th(IV) centres. UO 2 (OH 2 )(bipyO 2 ) 2 [Au(CN) 2 ] 2 ·3H 2 O ( 1 ) and Th(OH 2 ) 5 (bipyO 2 ) 2 [Au(CN) 2 ] 3 ·NO 3 ·H 2 O·CH 3 OH ( 3 ) have interpenetrated 2‐D frameworks as well as tetrameric and polymeric Au(I) chains, respectively. [UO 2 (OH 2 )] 2 (bipyO 2 ) 5 [Au(CN) 4 ] 4 ( 2 ) and Th(OH 2 ) 4 (bipyO 2 ) 4 [Au(CN) 4 ] 4 ·bipyO 2 ·3H 2 O·CH 3 OH ( 4 ) house their [Au(CN) 4 ] − anionic aggregates within square vacancies in their cationic framework. The structural similarities between the Au(I) ( 1 and 3 ) and Au(III) ( 2 and 4 ) compounds demonstrate the effect these cyanometallates impose on the self‐assembly process. To probe these supramolecular motifs, Hirshfeld surface analysis was used, demonstrating strong aurophilic interactions between [Au(CN) 2 ] − anions alongside strong H···N(cyano) hydrogen bonding anchoring with the surrounding framework. On the other hand, the [Au(CN) 4 ] − anions formed weaker dative Au···N(cyano) and H···N(cyano) interactions with each other and the surroundings, respectively; the weaker and less directional interactions allowing molecular shape to play a larger role in influencing the framework structure.