Coinage-metal-based cyclic trinuclear complexes (CTCs)[1] are a class of trimeric structures with the general formula M₃L₃, where M = Cu(I), Ag(I), or Au(I). Gold(I) CTCs are especially interesting due to their tunable π-acidity/basicity,[2] their ability to form strong intermolecular aurophilic interactions that drive self-assembly[3], and their capacity to form excimer/exciplex species and engage in diverse host–guest interactions. 

While studies have predominantly focused on the self-assembly of gold(I) CTCs via columnar stacking through metallophilic interactions, their behavior in aqueous environments, relevant for soft-matter applications, and their incorporation into extended architectures via dynamic, reversible linkages such as B–N bonds remain largely unexplored. Embedding gold(I) CTCs into supramolecular frameworks opens new possibilities for the development of functional materials with unique and versatile properties.

We are investigating the supramolecular potential of gold(I) CTCs in two complementary directions. Firstly, the self-assembly of an amphiphilic Au₃(pyrazolate)₃ complex in water leads to the formation of "nano onions" (Figure 1A.[4] We have investigated the influence of the metal center and of the position and number of the amphiphilic  side chains on the self-assembly. The nanostructures were characterized using cryo- and transmission electron microscopy, dynamic light scattering, and energy-dispersive X-ray spectroscopy.

In a parallel approach, we employed pyridine-functionalized Au₃(pyrazolate)₃ complexes as modular building blocks for the formation of coordination polymers with boronic esters via B–N dative bonds. These interactions yield 1D and 2D porous crystalline networks, with channels and cavities visible from their single-crystal packing (Figure 1B). These are the first examples of B–N-based supramolecular structures incorporating gold(I) CTCs, demonstrating the compatibility of metallophilic and dative interactions and offering new directions for the application of these complexes in supramolecular chemistry.

[1] J. Zheng, Z. Lu, K. Wu, G. H. Ning, D. Li, Chem. Rev. 2020, 120, 9675-9742. [2] M. A. Omary, M. A. Rawashdeh-Omary, M. W. Gonser, O. Elbjeirami, T. Grimes, T. R. Cundari, H. V. Diyabalanage, C. S. Gamage, H. V. Dias, Inorg. Chem. 2005, 44, 8200-8210. [3] H. Schmidbaur, A. Schier, Chem. Soc. Rev. 2012, 41, 370-412.   [4]  A. B. Solea, D. Dermutas, F. Fadaei-Tirani, L. Leanza, M. Delle Piane, G. M. Pavan, K. Severin, Nanoscale, 2025, 17, 1007-1012.