Structures of [Ag(tcm)], [Ag(tcm)(phz)1/2] and [Ag(tcm)(pyz)] (tcm=tricyanomethanide, C(CN)3-, phz=phenazine, pyz=pyrazine)

Abstract

The topologically unique sheet structure of [Ag(tcm)] [tcm=the tricyanomethanide ion, C(CN)₃^-] is retained in the derivative [Ag(tcm)(phz)_1/2] (phz=phenazine). The sheet structure is composite, consisting of two independent hexagonal grid nets which are corrugated so as to allow one to interpenetrate the other. The Ag⁺ ion is three-coordinate and provides half the three-connecting nodes of the hexagonal grid net, the others being provided by the tcm central carbon. [Ag(tcm)(phz)_1/2] contains essentially the same composite double sheets linked together by phenazine units that bridge between silver centres which thereby become four-coordinate. The topology of [Ag(tcm)(pyz)] (pyz=pyrazine) is very different; in this case the Ag(tcm) component forms a planar, non-corrugated hexagonal grid and each such sheet is connected on both sides to neighbouring sheets by pyrazine bridging ligands whereby the silver becomes five-coordinate and trigonal bipyramidal. Two such 3,5-connected three-dimensional nets then interpenetrate.