Polymerization of phenylacetylenes by binuclear rhodium catalysts with different para-binucleating phenoxyiminato linkages

Abstract

A binuclear rhodium catalyst 3b with a 2,5-phenyloxydiiminato linkage and an nbd ligand exhibits cooperative effects in terms of enhanced catalytic activity in the polymerization of phenylacetylene and its functional derivatives.

Rh(I)(2,5-norbornadiene)(biphenyl)(tris(4-fluorophenyl)phosphine): Synthesis, Characterization, and Application as an Initiator in the Stereoregular (Co)Polymerization of Phenylacetylenes

“…Their common use as initiators for these monomer families is due to their low oxophilicity, impressive functional group tolerance, ease of handling, and generally high activity. While the uncontrolled (co)­polymerization of arylacetylenes employing catalytic bridged dimers such as [Rh­(nbd)­Cl] 2 (nbd: 2,5-norbornadiene) or [Rh­(cod)­Cl] 2 (cod: 1,5-cyclooctadiene), as well as other Rh derivatives, , typically with an amine cocatalyst, is well documented, − there are comparatively few reports detailing the use of well-defined Rh­(I) catalysts for controlled (co)­polymerization of this important monomer class. − …”

Precise synthesis of multilevel branched organic microwires for optical signal processing in the near infrared region

“…DHNBP was synthesized via the six-step synthesis route shown in Scheme S1. Compound 3 was synthesized according to previously reported procedures [62], which is proceeded by a two-step acetylation reaction to form Compound 5. After demethylation by BBr 3 , Compound 6 can be obtained.…”

“…S11). The data can be well fitted by a cosine quadratic function (cos 2 θ), which is a characteristic of polarized emission from uniaxially oriented molecular crystals [62].…”

Unprecedented Application of Covalent Organic Frameworks for Polymerization Catalysis: Rh/TPB-DMTP-COF in Polymerization of Phenylacetylene and Its Functional Derivatives

“…Although there is a large amount of homogeneous binuclear Rh catalysts and heterogeneous supported Rh catalysts using a porous support such as molecular sieves, molecular cages made of polymers, metal complexes, or proteins as inorganic and organic supports have been reported over the past two decades, and they usually cannot exhibit the synergistic effect with moderate activity no more than 10 5 g•mol Rh −1 •h −1 . 20,34 Recently, we reported the unprecedented synergistic effect of the homogeneous binuclear Rh catalyst with 2,5-phenyloxydiiminato linkage (2,5- 34 We found that the synergistic effects of these binuclear Rh catalysts were mainly attributed to highly electrophilic characters and large steric hindrance of the Rh centers of the binuclear Rh active species, of which the former was determined by the π-acidity of phenoxyimine linkage and diene ligand and the latter was influenced by the distance between two Rh centers and the growth direction of polymer chains. More recently, we reported the uncommon synergistic effect of the MOF-supported Rh catalysts in PA polymerization.…”

“…Such an uncommon synergistic effect was only observed in PA polymerization catalyzed by the previous homogeneous binuclear 2,5-phenyloxydiiminato Rh catalyst and the MOFsupported Rh catalyst reported by us. 20,34 This might be due to uniformly distributed metal centers, synergistic effects among metals, increased local concentration of monomers, more exposure opportunities between the monomers and metal centers, and so on (Schemes 1 and 2). The PPAs had similar cis-selectivity, similar or higher molecular weights, and narrower molecular weight distributions than those obtained by the homogenous Rh catalysts f and g (Table 2 (entries 2− 5) and Table S1 (entries 1 and 8)).…”