Reactivity of polyiodides towards 1,3-bis(4-pyridyl)propane (bpp): A new CuI cluster polycatenane framework and a novel 2D AgI cluster motif

The solution-phase reactions of metal iodides or iodine with 1,3-bis(4-pyridyl)propane (bpp) yields four new organic-inorganic hybrid frameworks, namely [(CuI)₄(bpp)₄]_n (1), [(AgI)₆(bpp)]_n (2), [PbI₂(bpp)]_n (3), and [I₃(bppH)] (4), each of which adopts a different structural motif. For example, complex 1 is a 2D "open" coordination polymeric cluster consisting of a CuI₂Cu rhomboid cluster core coordinated by anti-anti and anti-gauche bpp interactions to produce an interpenetrating 2D (4,4) polycatenane net; 2 is a novel bpp inclusion compound with a unique 2D polymeric hexagonal prism-shaped [Ag₆I₆]_n cluster motif; compound 3 is also a 2D "open" supramolecular cluster made from [PbI₂]_n "ribbons" and bpp bridges; compound 4 is a triiodide made up of organic [bppH]⁺ cations and a I₃^- anion chain. The clusters 1-3 obtained from the reaction between polyiodide complexes and an organic ligand suggest that this simple synthetic approach is likely to be applicable to the construction of polymeric clusters. The third-order NLO effects of 1 were studied by Z-scan techniques. The polymeric cluster exhibits good nonlinearities and the effective third-order NLO refractive index (n₂) value is 2.56 × 10 ^-12 esu which is comparable to those of most cluster monomers and polymers.