Polycatenanes Formed of Self-Assembled Metal Organic Cages

In this contribution, of properties of poly-[n]-catenanes composed of interlocked M12L8 icosahedral nanometric cages are investigated by Quantum Chemical (QC) calculations and X-ray diffraction experiments [1]. The TPB (exotridentate trispyridyl benzene) ligand and ZnCl2, in the presence of appropriate templating molecules (Figure 1), form metal−organic nanocages microcrystalline materials. Single-crystal X-ray data collected at 100 K allowed to solve the structure and to detect guest molecules at the internal walls together wih highly disordered solvent in the central part. The processes of guests absorption and release are driven by intramolecular and intermolecular interactions. QC calculations [2] were used to study packing energies and host-guest interactions. Key factors in the formation of the poly-[n]-catenane and in solvent exchange are rationalized throught a mechanism of “closed-open” dynamic channels. The labile nature of the Zn−N coordination bonds allows the recyclability of TPB ligand in water, thus making these materials very good candidates in green chemistry applications. Figure 1. Sketch of the synthesis of poly-[n]-catenane and a view of the crystalline phase. Acknowledgements J. M.-R. thanks Politecnico di Milano for Fondo Chiamata Diretta Internazionalizazzione (Prg. Id. 61566). A. F. and J. M.-R acknowledge PRIN Project “SCINTILLA” (2022SCWMT2). The authors acknowledge NeXt GAME Laboratory at Politecnico di Milano (single crystal X-ray diffraction data). References [1] a) S. Torresi, A. Famulari, J. Martí-Rujas, J. Am. Chem. Soc., 2020, 142, 9537-9543; b) Angew. Chem. Int. Ed., 2024 (on line). [2] a) A. Famulari, G. Raos, A. Baggioli, M. Casalegno, R. Po, S.V. Meille, J. Phys. Chem. B, 2012, 116, 14504-14509; b) H. Li, F. Guo, M. Kou, A. Famulari, Q. Fu, J. Martí-Rujas, J. Inorg. Chem., 2017, 56, 6584-6590; c) L. Catalano, D.P. Karothu, S. Schramm, E. Ahmed, R. Rezgui, T.J. Barber, A. Famulari, P. Naumov, Angew. Chem. Int. Ed. , 2018, 57, 17254-17258.   BIOGRAPHY: Antonino Famulari is Associate Professor at Politecnico di Milano since 2014. Ph.D. in Chemistry at the Università degli Studi di Milano (1997, Prof. Raimondi). He was post-doc at CNR and Università degli Studi di Milano and CNR researcher (1998-2000). He has been visiting at the University of Liverpool (Prof. Cooper), Iowa State University (Prof. Gordon) and University of Copenaghen (Prof. Rettrup). In 2001 he joined the group of Prof. Allegra and Prof. Meille) at the Politecnico di Milano. Research activity focalized in the framework of material characterization, including molecular modelling (quantum chemistry) and X-Ray diffraction methods (WAXS/SAXS).