Rigidity/flexibility competition in organic/iodoargentate hybrids: a combined experimental and theoretical study

We extend our efforts to investigate the influence of ligand spacers on iodoargentate hybrids templated by cationic SDAs [structure-directing agents, BPB2+ (1,4-bis(pyridinium)butane), BPO2+ (1,8-bis(pyridinium)octane)] possessing both rigidity and flexibility and two iodoargentate hybrids [(BPB)(Ag5I7)]n (1), [(BPO)(Ag5I7)]n (2) have been synthesized in polar organic solvents. 1 exhibits a 3-D network with BPB2+ cations trapped in the 3-D (Ag5I7)n2− cavities and 2 contains one-dimensional infinite polymeric anions accompanied by discrete SDA cations. Interestingly, judging from structural analysis and DFT calculations, we find that the rigidity/flexibility competition will achieve a balance when the ligand spacer n is 4, where the most versatile structure and stable confirmation can be presented. Their adsorption and fluorescent spectra are also discussed.