Exploring Ag•••H-B interactions in coordination polymers: silver-alkanedinitrile networks with cobalt carbaborane anions

Uncommon silver coordination environments occupied exclusively by Ag center dot center dot center dot H-B interactions, namely Ag center dot center dot center dot(H-B)(4) and Ag center dot center dot center dot(H-B)(6) centres, were observed in two novel coordination polymers, [Ag(pim)(Cobdc)][Ag(Cobdc)] (1) (pim = pimelonitrile, CN(CH2)(5)CN, and Cobdc = cobalt(III) bis(dicarbollide) anion, [Co(C2B9H11)(2)](-)) and [Ag-3(sub)(2)(Cobdc)(3)] (2) (sub = suberonitrile, CN(CH2)(6)CN). The Ag center dot center dot center dot(H-B)(4) centre was observed in compound 1 and shows a geometry that resembles an extremely distorted tetrahedron, while a highly distorted octahedral centre Ag center dot center dot center dot(H-B)(6) was found in 2. The two compounds were isolated as crystalline materials, their structures established by single crystal X-ray diffraction and also characterized by CHN elemental analysis and infrared spectroscopy. The compounds 1 and 2 feature neutral 1D and 2D coordination polymers, [Ag(pim)(Cobdc)](infinity)(1) and [Ag-3(sub)(2)(Cobdc)(3)](infinity)(2), respectively.