Soluble organic supports for the non-covalent immobilization of homogeneous catalysts; modular approaches towards sustainable catalysts

Polyglycerol‐Supported Chromium‐Salen as a High‐Loading Dendritic Catalyst for Stereoselective Diels–Alder Reactions

“…[1,2] Investigations on polymer-supported catalysts have been ongoing for many decades, and rapidly increasing numbers of new polymeric supports, cross-linked (insoluble) [3] and non-cross-linked (soluble) polymers, [4,5] have recently been reported. Since one of the major benefits of polymer-supported catalysis is the recovery and reuse of immobilized species, especially when dealing with chiral catalysts, which can be extremely expensive, [4a] effective separation methods are required.…”

“…[6] Soluble polymers can be separated from low molecular weight compounds in solution either by physicochemical properties, e.g., extraction, precipitation, filtration over silica gel, or by size (ultrafiltration, dialysis, GPC). [4][5][6][7] Tetradentate Schiff bases known as salen [N,N'-bis-(salicylidene)ethylenediamine], are powerful ligands for asymmetric catalysis. [8] The best known and most widely used is the so-called Jacobsens catalyst 1 (Figure 1), [9] whereas the most selective are those developed by Katsuki and co-workers.…”

Steric, Electronic, and Secondary Effects on the Coordination Chemistry of Ionic Phosphine Ligands and the Catalytic Behavior of Their Metal Complexes

“…[56] The cone angles of 12 c and 14 were calculated by computational methods and are slightly larger than that of PA C H T U N G T R E N N U N G (tBu) 3 (Table 1, entries 12, 13, and 15). [51] Similar to alkylammonium groups, Baird et al [59] showed that alkylphosphonium substituents act as electron-withdrawing functionalities in Phophos ligands (17). This effect decreases with an increasing number of methylene groups in between the phosphorus atom and the PMe 3 + functionality, indicating the insulating effect of methylene spacers, as indicated by the CO stretching frequencies of the corresponding [Fe(CO) 4 L] complexes (Table 2, entries [43][44][45][46].…”

“…[14] In addition to their use in aqueous systems, ligands containing ionic functionalities have also found applications in the immobilization of homogeneous catalytic systems in ionic liquids. [15,16] Furthermore, the use of ionic interactions has emerged as one of the most effective ways to immobilize organometallic catalysts onto dendrimers, [17] ion-exchange resins, [18] or other soluble and insoluble supports.[19] The advantage that ionic-tagged ligands offer with respect to the characterization of their respective metal complexes by electrospray ionization mass spectrometry (ESI-MS), has also been recognized. [20] The functionalization of phosphine ligands with ionic groups may have profound effects on fundamental aspects of the coordination chemistry of these ligands with respect to a transition metal.…”

Dissipative Particle Dynamics Simulation of Microphase Separation and Properties of Linear–Dendritic Diblock Copolymer Melts under Steady Shear Flow

“…Dendrimers have many important properties as a result of their unique architecture, and have been used as drugdelivery materials, catalysts, [1][2][3][4] etc. Recently, a hybrid structure consisting of a dendrimer attached covalently to a linear block, namely linear-dendritic copolymers, has appeared.…”