Controlling the supramolecular polymerization of dinuclear isocyanide gold(i) arylethynylene complexes through tuning the central π-conjugated moiety†
Three dinuclear gold(I) p-arylene(diethynyl) complexes with the same peripheral isocyanide ligation and different central conjugated moieties have been prepared and their supramolecular polymerization was comprehensively studied. The central, core-forming π-conjugated arylene moieties present in the complexes have been shown to exhibit a pronounced influence on the resulting photophysical properties, self-assembly mechanisms, morphologies and gelation behavior of the supramolecular polymers. Complexes 1 and 2 bearing biphenylene and phenylene central chromophores exhibit a cooperative mechanism during the supramolecular polymerization, with the appearance of pronounced low-energy phosphorescence attributed to the aurophilic interactions. In contrast, compound 3 with a central benzothiadiazole moiety was found to undergo self-assembly via an isodesmic mechanism. Due to the presence of stronger π–π interactions, complexes 1 and 3 possess lower ΔG0 values for self-assembly and a stronger tendency to form metallogels. Given the balance between the non-covalent interaction enthalpy of the core-forming moieties and intercoronal chain repulsion, 1 and 3 tend to form one-dimensional fibers, while 2 with a short central chromophore is likely to form zero-dimensional spherical aggregates.