unique rigid rod helical structure and broad applications including, but not limited to, enantiomer separation, chiral recognition, asymmetric catalysis, circularly polarized luminescence, etc. [16-27] Helical PPIs with different functions, for example, ultraviolet light-response coming from azobenzene groups [28] or thermo-response originating from oligoethylene glycols groups, [29] have been reported recently. Meanwhile, efforts have been paid to fabricate helical PPIs with different chemical structures, such as polymer brushes [30] and star polymers. [31] However, as far as we know, helical PPIs with dendrimer-like structure have been rarely investigated. In order to mimic natural products, polymer chemists have developed a variety of polymers with different topological structures, such as linear, [32] cyclic, [33,34] star, [35,36] graft, [37,38] branched, [39,40] dendritic, [41,42] and so on. Among them, dendrimer-like polymers are a special type of macromolecules with unusual structural and transport properties. [43-45] In comparison with linear polymers with the same molecular weight and composition, dendrimer-like polymers are usually with a lower solution viscosity and can self-assemble into more stable supramolecular aggregates with a lower critical aggregation concentration. They have lots of potential applications in drug delivery, viscosity modifiers, stimuli sensitive molecules, chemical catalysts, and so on. [46-49] Although many families of dendrimer-like polymers have been produced, helical polymers with dendrimer-like structure, which are expected to present interesting properties, have been seldom reported. Dendrimer-like polymers are usually synthesized by using a stepwise repetitive reaction sequence which guarantees a very highly monodispersed polymer with a hyperbranched topology radiating from a central core and grown generation by generation. Generally, there are two approaches to prepare dendrimerlike polymers, that is, the divergent method from the core outward and the convergent method from the surface to the focal point. [50] Herein, dendrimer-like helical PPIs were designed and synthesized by a new stepwise iterative method as shown in Scheme 1. First, hydroxyl functionalized palladium catalyst (catalyst 1) was prepared according to Scheme 1A. At the same time, decyl 4-isocyanobenzoate (monomer 1) was polymerized using a phenyl alkyne-Pd(II) complex as the initiator to A new stepwise iterative method is developed for the synthesis of well-defined dendrimer-like helical poly(phenyl isocyanide)s (PPIs). The method mainly involves the following three reaction steps in an iterative process: 1) the polymerization of decyl 4-isocyanobenzoate (monomer 1) or 4-isocyanobenzoyl-2-aminoisobutyric acid decyl ester (monomer 2) to afford the polymer, 2) reacting one pentafluorophenyl (PFP) ester-functionalized phenyl isocyanide (monomer 3) at the end of the polymer, followed by the treating of PPh 3 to remove the-Pd(PEt 3) 2 Cl groups, and 3) the transesterification reaction of the PFP group with h...
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