Control of copper(I) iodide architectures by ligand design: angular versus linear bridging ligands

A family of coordination polymers formed by the reaction of copper(I) iodide with a range of angular bidentate or tridentate N-donor ligands is reported. The framework polymers CuI(dpt)](infinity) 1 dpt = 2,4-bis(4-pyridyl)-1,3,5-triazine], CuI(dpb)](infinity) 2 dpb = 1,4-bis-(4-pyridyl)-benzene], (CuI)3(dpypy)2](infinity) 3, CuI(dpypy)](infinity) 4 dpypy = 3,5-bis(4-pyridyl)-pyridine], and Cu3I3(pypm)](infinity) 5 pypm = 5-(4-pyridyl)pyrimidine] have been prepared and structurally characterized. It was found that the angular nature of the dpypy and dpt ligands favors the formation of discrete (CuI)2 dimeric subunits as observed in CuI(dpt).MeCN](infinity) 1 and (CuI)3(dpypy)2](infinity) 3. In contrast, reaction with the linear ligand dpb affords CuI(dpb)](infinity) 2 which incorporates a one-dimensional (CuI)(infinity) chain structure. Moreover, the additional donor available on the central ring of the dpypy ligand generates a novel two-dimensional bilayer structure in 3, in contrast to the one-dimensional ribbon structure observed in the case of 1. Interestingly, the bilayer structure of 3 additionally exhibits 2-fold interpenetration. The reaction of CuI with dpypy produces not only 3 but a further product CuI(dpypy)](infinity) 4 that has been characterized as a one-dimensional chain constructed from trigonal-planar Cu(I) centers bridged by bidentate dpypy ligands. Compound 5, Cu3I3(pypm)](infinity), exhibits a highly unusual three-dimensional structure in which the pypm ligand bridges two-dimensional brick-wall (CuI)(infinity) sheets.