2D networks of metallo-capsules and other coordination polymers from a hexapodal ligand

Abstract

The hexapodal ligand hexakis(isonicotinoyl)cyclotricatechylene (L1) belonging to the cyclotriveratrylene family of host-molecules has been synthesised and used in the assembly of a series of coordination polymer materials with Re(I), Co(II), Cu(II), Ni(II) and Ag(I) salts. Single crystal structures of the coordination polymers [Re₃(L1)₂Br₃(CO)₃] 1, and an isomorphic [M₃L₂] series where M = Co, Cu or Ni, reveal 2D framework structures with a simplified topology of 3⁶ or hxl. These are composed of M₆(L1)₂ metallo-cages linked together in a pair-wise fashion through each metal centre. Compound 1 is a rare example of a rhenium coordination polymer and was investigated for guest uptake from solution, complexing I₂. The mixed-ligand species [Cu₂(L1)(CF₃CO₂)₃(isonicotinate)] forms a (3,4,5)-connected 2D coordination polymer, while [Ag₂(L1)(DMF)₂]·2BF₄·2(H₂O)·6(DMF) features a 2D network of (3,6)-connectivity and with kagome dual (kgd) topology.