Zinc Imine Polyhedral Oligomeric Silsesquioxane as a Quattro‐Site Catalyst for the Synthesis of Cyclic Carbonates from Epoxides and Low‐Pressure CO₂

Abstract

In the present research, the synthesis, spectroscopic characterization, and structural investigations of a unique ZnII complex of imine‐functionalized polyhedral oligomeric silsesquioxane (POSS) is designed, and hereby described, as a catalyst for the synthesis of cyclic carbonates from epoxides and CO2. The uncommon features of the designed catalytic system is the elimination of the need for a high pressure of CO2 and the significant shortening of reaction times commonly associated with such difficult transformations like that of styrene oxide to styrene carbonate. Our studies have shown that imine‐POSS is able to chelate metal ions like ZnII to form a unique coordination complex. The silsesquioxane core and the hindrance of the side arms (their steric effect) influence the construction process of the homoleptic Zn4@POSS‐1 complex. The compound was characterized in solution by NMR (1H, 13C, 29Si), ESI‐MS, UV/Vis spectroscopy and in the solid state by thermogravimetric/differential thermal analysis (TG‐DTA), elemental analysis, diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), cross‐polarization magic angle spinning (CP MAS) NMR (13C, 29Si) spectroscopy, and X‐ray crystallography.

Terpolymerization of CO2 with Epoxides and Cyclic Organic Anhydrides or Cyclic Esters

“…In particular, the alternating ring-opening copolymerization (ROCOP) of CO 2 with epoxides has offered a conceptually simple route for the synthesis of aliphatic polycarbonates (APC), which show a clear advantage in terms of biodegradability with respect to polyolefins [4][5][6]. APC, however, often display poor chemical and mechanical properties compared to aromatic polycarbonates, and the incorporation of epoxides with various structural features does not always result in an improvement in the final properties of APC [7][8][9].…”

Siloxane Matrix Molecular Weight Influences the Properties of Nanocomposites Based on Metal Complexes and Dielectric Elastomer

“…With structures built around nitrogen atoms and ease of synthesis, the Schiff bases are desirable chelating agents [ 29 ]. The ease of synthesis allows the tuning of the properties of interest of the Schiff bases for targeted applications in biomimetic chemistry [ 30 ], analytical chemistry [ 31 ], materials chemistry [ 32 ], and catalysis [ 33 , 34 , 35 , 36 ], with efficient catalysis of click reaction in aqueous media [ 37 ], cyclic carbonates [ 38 ], spin crossover complexes and materials for magnetic recording [ 39 , 40 , 41 ], and single crystal materials with large dielectric constant [ 42 ]. The ability of Schiff bases to coordinate the metal within the polymer-based macromolecules provides the functionality required for sensors and actuators [ 43 , 44 ].…”

Zinc (II) and AIEgens: The “Clip Approach” for a Novel Fluorophore Family. A Review

“…Multifunctional nanosized probes for cell imaging, drug-carrying, and metal ion detection are effective cutting-edge in scientific research. Recently, hybrid organic–inorganic nanoprobes based on the bio-friendly zinc (II) cation [ 169 , 170 , 171 , 172 , 173 ] have been explored as highly engineered sensors and markers for bioimaging [ 63 , 126 ]. Rare articles have been produced in which the link between the AIE properties and the sensing ability has been highlighted and explored.…”