First Characterization of an Extended Ammonium‐Ammonia Complex [{NH₄(NH₃)₄}⁺(μ‐NH₃)₂] in the Crystal Structure of [NH₄(NH₃)₄][Co(C₂B₉H₁₁)₂] · 2 NH₃

Abstract

Abstract The compound [NH 4 (NH 3 ) 4 ][Co(C 2 B 9 H 11 ) 2 ] · 2 NH 3 ( 1 ) was prepared by the reaction of Na[Co(C 2 B 9 H 11 ) 2 ] with a proton‐charged ion‐exchange resin in liquid ammonia. The ammoniate 1 was characterized by low temperature single‐crystal X‐ray structure analysis. The anionic part of the structure consists of [Co(C 2 B 9 H 11 ) 2 ] ‐ complexes, which are connected via C‐H···H‐B dihydrogen bonds. Furthermore, 1 contains an infinite [{NH 4 (NH 3 ) 4 } + ( μ ‐NH 3 ) 2 ] cationic chain, which is formed by [NH 4 (NH 3 ) 4 ] + ions linked by two ammonia molecules. The N‐H···N hydrogen bonds range from 1.92 to 2.71Å (DHA = Donor···Acceptor angles: 136‐176°). Additional N‐H···H‐B dihydrogen bonds are observed (H···H: 2.3‐2.4Å).