Coordination Polymers with Carborane Anions:  Silver Dinitrile Complexes

Crystalline materials have been isolated and characterized from mixing the silver carborane salts Ag(CB₁₁H₁₂) or Ag[Co(C₂B₉H₁₁)₂] with nitrile ligands, either terminal acetonitrile or potentially bridging alkanedinitriles. Most of the complexes showed B−H···Ag interactions between the silver center and carborane anion. [Ag(acetonitrile)₂(CB₁₁H₁₂)] has a hexagonal network structure. [Ag(malonitrile)₂(CB₁₁H₁₂)] is a discrete dimeric complex, while [Ag₄(succinonitrile)₅(CB₁₁H₁₂)₄], [Ag(glutaronitrile)₂][Co(C₂B₉H₁₂)₂], and {Ag(glutaronitrile)[Co(C₂B₉H₁₁)₂]} all show coordination chain structures. The carborane anions in {Ag(adiponitrile)[Co(C₂B₉H₁₁)₂]} bridge between Ag centers to give a 3D CdSO₄-related coordination polymer. The structure of [Ag(malonitrile)₂](BF₄) was also determined to have an unusual chiral diamondoid structure with a skewed 2-fold interpenetration.