Polymerization Of Phenylacetylene Research Articles

Synthesis of rhodium catalyst [Rh(cod)(TTT)2] with amino group ligand and its catalytic performance for phenylacetylene polymerization

Synthesis of rhodium catalyst [Rh(cod)(TTT)2] with amino group ligand and its catalytic performance for phenylacetylene polymerization

Vanadium Alkylidyne Initiated Cyclic Polymer Synthesis: The Importance of a Deprotiovanadacyclobutadiene Moiety.

Reported is the catalytic cyclic polymer synthesis by a 3d transition metal complex: a V(V) alkylidyne, [(dBDI)V≡CtBu(OEt2)] (1-OEt2), supported by the deprotonated β-diketiminate dBDI2- (dBDI2- = ArNC(CH3)CHC(CH2)NAr, Ar = 2,6-iPr2C6H3). Complex 1-OEt2 is a precatalyst for the polymerization of phenylacetylene (PhCCH) to give cyclic poly(phenylacetylene) (c-PPA), whereas its precursor, complex [(BDI)V≡CtBu(OTf)] (2-OTf; BDI- = [ArNC(CH3)]2CH, Ar = 2,6-iPr2C6H3, OTf = OSO2CF3), and the zwitterion [((C6F5)3B-dBDI)V≡CtBu(OEt2)] (3-OEt2) exhibit low catalytic activity despite having a neopentylidyne ligand. Cyclic polymer topologies were verified by size-exclusion chromatography (SEC) and intrinsic viscosity studies. A component of the mechanism of the cyclic polymerization reaction was probed by isolation and full characterization of 4- and 6-membered metallacycles as model intermediates. Metallacyclobutadiene (MCBD) and deprotiometallacyclobutadiene (dMCBD) complexes (dBDI)V[C(tBu)C(H)C(tBu)] (4-tBu) and (BDI)V[C(tBu)CC(Mes)] (5-Mes), respectively, were synthesized upon reaction with bulkier alkynes, tBu- (tBuCCH) and Mes-acetylene (MesCCH), with 1-OEt2. Furthermore, the reaction of the conjugate acid of 1-OEt2, [(BDI)V≡CtBu(OTf)] (2-OTf), with the conjugated base of phenylacetylene, lithium phenylacetylide (LiCCPh), yields the doubly deprotio-metallacycle complex, [Li(THF)4]{(BDI)V[C(Ph)CC(tBu)CC(Ph)]} (6). Protonation of the doubly deprotio-metallacycle complex 6 yields 6-H+, a catalytically active species toward the polymerization of PhCCH, for which the polymers were also confirmed to be cyclic by SEC studies. Computational mechanistic studies complement the experimental observations and provide insight into the mechanism of cyclic polymer growth. The noninnocence of the supporting dBDI2- ligand and its role in proton shuttling to generate deprotiometallacyclobutadiene (dMCBD) complexes that proposedly culminate in the formation of catalytically active V(III) species are also discussed. This work demonstrates how a dMCBD moiety can react with terminal alkynes to form cyclic polyalkynes.

Metallacyclobuta-(2,3)-diene: A Bidentate Ligand for Stream-line Synthesis of First Row Transition Metal Catalysts for Cyclic Polymerization of Phenylacetylene.

Described here is a direct entry to two examples of 3d transition metal catalysts that are active for the cyclic polymerization of phenylacetylene, namely, [(BDI)M{κ2 -C,C-(Me3 SiC3 SiMe3 )}] (2-M) (BDI=[ArNC(CH3 )]2 CH- , Ar=2,6-i Pr2 C6 H3 ; M=Ti, V). Catalysts are prepared in one step by the treatment of [(BDI)MCl2 ] (1-M, M=Ti, V) with 1,3-dilithioallene [Li2 (Me3 SiC3 SiMe3 )]. Complexes 2-M have been spectroscopically and structurally characterized and the polymers that are catalytically formed from phenylacetylene were verified to have a cyclic topology based on a combination of size-exclusion chromatography (SEC) and intrinsic viscosity studies. Two-electron oxidation of 2-V with nitrous oxide (N2 O) cleanly yields a [VV ] alkylidene-alkynyl oxo complex [(BDI)V(=O){κ1 -C-(=C(SiMe3 )CC(SiMe3 ))}] (3), which lends support for how this scaffold in 2-M might be operating in the polymerization of the terminal alkyne. This work demonstrates how alkylidynes can be circumvented using 1,3-dianionic allene as a segue into M-C multiple bonds.

Metallacyclobuta‐(2,3)‐diene: A Bidentate Ligand for Stream‐line Synthesis of First Row Transition Metal Catalysts for Cyclic Polymerization of Phenylacetylene

AbstractDescribed here is a direct entry to two examples of 3d transition metal catalysts that are active for the cyclic polymerization of phenylacetylene, namely, [(BDI)M{κ2‐C,C‐(Me3SiC3SiMe3)}] (2‐M) (BDI=[ArNC(CH3)]2CH−, Ar=2,6‐iPr2C6H3; M=Ti, V). Catalysts are prepared in one step by the treatment of [(BDI)MCl2] (1‐M, M=Ti, V) with 1,3‐dilithioallene [Li2(Me3SiC3SiMe3)]. Complexes 2‐M have been spectroscopically and structurally characterized and the polymers that are catalytically formed from phenylacetylene were verified to have a cyclic topology based on a combination of size‐exclusion chromatography (SEC) and intrinsic viscosity studies. Two‐electron oxidation of 2‐V with nitrous oxide (N2O) cleanly yields a [VV] alkylidene‐alkynyl oxo complex [(BDI)V(=O){κ1‐C‐(=C(SiMe3)CC(SiMe3))}] (3), which lends support for how this scaffold in 2‐M might be operating in the polymerization of the terminal alkyne. This work demonstrates how alkylidynes can be circumvented using 1,3‐dianionic allene as a segue into M−C multiple bonds.

Stereoregular polymerization of phenylacetylene using alkynyl and methyl rhodium(i) complexes with functionalized phosphine ligands: linear vs. branched poly(phenylacetylene)s

Alkynyl rhodium(i) complexes with functionalized phosphine ligands efficiently catalyze the polymerization of phenylacetylene to give a highly stereoregular linear poly(phenylacetylene) with a fraction of high molecular weight branched polymer.

Synthesis of megadalton stereoregular ring-substituted poly(phenylacetylene)s by a rhodium(i) catalyst with a N-functionalized hemilabile phosphine ligand

The compound [Rh(nbd){κ2P,N-Ph2P(CH2)3NMe2}][BF4] efficiently catalyzes the polymerization of ring-substituted phenylacetylenes to give highly stereoregular megadalton and ultra-high molecular weight polymers with moderate dispersity.

Snapshot of cyclooctyne ring-opening to a tethered alkylidene cyclic polymer catalyst.

Cyclooctyne reacts with the trianionic pincer ligand supported alkylidyne [ t BuOCO]WCC(CH3)3(THF)2 (1) to yield tungstacyclopropene (3) and tungstacyclopentadiene (4) complexes. The ratio of 3 and 4 in the reaction mixture depends on the stoichiometry of the reaction. The maximum concentration of 3 occurs with one equiv. of cyclooctyne and 4 is the exclusive product of the reaction above three equivalents. Both complexes 3 and 4 convert to the cyclooctyne ring-opened product 5 upon heating. While the conversion of 4 to 5 is accompanied by formation of polycyclooctyne as a white precipitate during the reaction, conversion of 3 to 5 is homogeneous. Exhibiting Ring Expansion Polymerization (REP), complexes 4 and 5 initiate the polymerization of phenylacetylene to generate cyclic poly(phenylacetylene) (c-PPA).

Solving fundamental concepts in supramolecular science with functionality-tolerant living polymerizations of self-assembling monomers and dendronized monomers

The evolution and development of several examples of functionality-tolerant living polymerizations to the level of perfection that they could be employed to solve fundamental concepts in supramolecular science by living polymerization of self-assembling monomers and self-organizable dendronized monomers is briefly reviewed. The review focuses on the development of the living polymerization methodology with brief examples on how they impacted the field of self-assembly and self-organization. The first polymerization reaction discussed is the stereoselective polymerization of phenylacetylene and of other arylacetylenes to generate helical poly(arylacetylene) stereoisomers. The transition from functionality non-tolerant to functionality-tolerant stereoselective polymerizations and the evolution to functionality-tolerant living stereoselective polymerization of phenylacetylene is used as the main example of this brief review. This living polymerization methodology is followed by living polymerization of vinyl ethers, oxazolines, of group transfer polymerization, of cationic ring-opening polymerization of cyclic siloxanes combined with hydrosilylation, of ROMP of cylooxanorbornene. This brief review is concluded by a brief discussion of the capabilities of the above-mentioned living methodologies with living radical polymerizations. The numerous applications in the field of supramolecular science of these living methodologies are not reviewed. However, the reader is directed to numerous comprehensive review articles discussing these applications. The challenges that remain to be solved in all these functionality-tolerant living polymerizations are presented.

Synthesis of a novel phosphate-containing ligand rhodium catalyst and exploration of its optimal reaction conditions and mechanism for the polymerization of phenylacetylene

Abstract Due to the chemical properties of Group VIII transition metals and their importance in catalytic processes, the reactions of rhodium and its neighboring organic complexes have received much attention as model systems. In the present experiments, we successfully prepared two new rhodium complexes named [Rh(cod)(TTP)Cl] and [Rh(cod)(CDP)Cl] using tri(o-tolyl)phosphine and clohexyldiphenylphosphine as ligands, respectively, and the proofs of their structures were completed using 1H NMR and 13C NMR. Subsequently, it was applied to the polymerization reaction of phenylacetylene (PA), and the effects of different solvents, time, and temperature on the yield and molecular weight of the polymerization reaction products were discussed. The experimental results show that both complexes can play a catalytic role in the polymerization of PA. From the point of view of polymer molecular weight, the best reaction conditions for both catalysts were 3 h at 20°C in THF solvent (molecular weight up to 2.40 × 105). From the point of view of yield, the best reaction conditions for both catalysts were 4 h at 35°C in THF solvent (yield up to 89.2%).

Novel Route to Cationic Palladium(II)-Cyclopentadienyl Complexes Containing Phosphine Ligands and Their Catalytic Activities.

The Pd(II) complexes [Pd(Cp)(L)n]m[BF4]m were synthesized via the reaction of cationic acetylacetonate complexes with cyclopentadiene in the presence of BF3∙OEt2 (n = 2, m = 1: L = PPh3 (1), P(p-Tol)3, tris(ortho-methoxyphenyl)phosphine (TOMPP), tri-2-furylphosphine, tri-2-thienylphosphine; n = 1, m = 1: L = dppf, dppp (2), dppb (3), 1,5-bis(diphenylphosphino)pentane; n = 1, m = 2 or 3: 1,6-bis(diphenylphosphino)hexane). Complexes 1-3 were characterized using X-ray diffractometry. The inspection of the crystal structures of the complexes enabled the recognition of (Cp-)⋯(Ph-group) and (Cp-)⋯(CH2-group) interactions, which are of C-H…π nature. The presence of these interactions was confirmed theoretically via DFT calculations using QTAIM analysis. The intermolecular interactions in the X-ray structures are non-covalent in origin with an estimated energy of 0.3-1.6 kcal/mol. The cationic palladium catalyst precursors with monophosphines were found to be active catalysts for the telomerization of 1,3-butadiene with methanol (TON up to 2.4∙104 mol 1,3-butadiene per mol Pd with chemoselectivity of 82%). Complex [Pd(Cp)(TOMPP)2]BF4 was found to be an efficient catalyst for the polymerization of phenylacetylene (PA) (catalyst activities up to 8.9 × 103 gPA·(molPd·h)-1 were observed).

Niobium Complexes Supported by Chalcogen-Bridged [OEO]-Type Bis(phenolate) Ligands (E = S, Se): Synthesis, Characterization, and Phenylacetylene Polymerization.

Trichloro niobium(V) complexes 3 and 4 with the sulfur- or selenium-bridged [OEO]-type bis(phenolate) ligands (E = S, Se) were synthesized and fully characterized on the basis of their NMR spectroscopic data and X-ray crystallographic analysis. In the crystalline state of 4, the [OSeO]-core of the ligand was coordinated to the niobium center in a fac-fashion. The corresponding tribenzyl niobium(V) complexes 5 and 6 were also prepared by the reactions of 3 and 4 with 3 equivalents of PhCH2MgCl in toluene. The X-ray diffraction analysis of 6 revealed that the distorted six-coordinated niobium center incorporated in the [OSeO]-type ligand took a mer-fashion, and one benzyl ligand was coordinated to the niobium center by η2-fashion. Complexes 5 and 6 were tested for the phenylacetylene polymerization that produced poly(phenylacetylene)s (PPAs), oligomers, and triphenylbenzenes (TPBs) depending on the chalcogen atom in the [OEO]-type ligand.

Synthesis of optically active star polymers consisting of helical poly(phenylacetylene) chains by the living polymerization of phenylacetylenes and their chiroptical properties.

Star polymers consisting of three helical poly(phenylacetylene) chains with a precisely controlled molecular weight (molar mass dispersity < 1.03) were successfully synthesized by the living polymerization of phenylacetylene derivatives with a Rh-based multicomponent catalyst system comprising trifunctional initiators, which have three phenylboronates centered on a benzene ring, the Rh complex [Rh(nbd)Cl]2, diphenylacetylene, triphenylphosphine, and a base. The analysis of chiroptical properties of the optically active star polymers obtained by the living polymerization of optically active phenylacetylene derivatives revealed that the star polymers exhibited chiral amplification properties owing to their unique topology compared with the corresponding linear polymers.

“On Water” Effect for Green Click Reaction: Spontaneous Polymerization of Activated Alkyne with “Inert” Aromatic Amine in Aqueous Media

“On Water” Effect for Green Click Reaction: Spontaneous Polymerization of Activated Alkyne with “Inert” Aromatic Amine in Aqueous Media

Synthesis of rhodium catalysts with amino acid or triazine as a ligand, as well as its polymerization property of phenylacetylene

Abstract Three novel rhodium complexes, with l-tyrosine (l-Tyr), l-arginine (l-Arg), or 2,4-diamino-6-phenyl-1,3,5-triazine (Dpt) as a ligand, named as [Rh(cod)(l-Tyr)], [Rh(cod)(l-Arg)], and [Rh(cod)(Dpt)2], respectively, had been synthesized for catalyzing the polymerization of phenylacetylene. Their yields were 62.34, 54.87, and 58.21%, respectively, by the most suitable synthesis conditions at 25°C for 4 h. The structures and purity of these complexes were proved by 1H NMR, element analysis, and scanning electron microscope (SEM). It has been examined that phenylacetylene could be polymerized by the three complexes as catalysts with high degrees of polymerization (n = 368, 385, and 664, respectively) and yields (about 87.62, 88.39, and 59.67%, respectively). In conclusion, compared with traditional [Rh–N] type catalysts, the novel [N–Rh–N] type catalyst ([Rh(cod)(Dpt)2]) gained better catalytic performance. By comparing the yield, Mw, and degree of their polymerization, the polymerization mechanism was found under the [N–Rh–N] type rhodium catalyst system.

Frontispiz: Well‐Controlled Living Polymerization of Phenylacetylenes in Water: Synthesis of Water‐Soluble Stereoregular Telechelic Poly(phenylacetylene)s

Polymerisation In ihrem Forschungsartikel (e202202676) berichten Tsuyoshi Taniguchi, Katsuhiro Maeda et al. über die Synthese von wasserlöslichen stereoregulären telechelen Poly(phenylacetylenen) durch lebende Polymerisation in Wasser.

Frontispiece: Well‐Controlled Living Polymerization of Phenylacetylenes in Water: Synthesis of Water‐Soluble Stereoregular Telechelic Poly(phenylacetylene)s

Polymerization In their Research Article (e202202676), Tsuyoshi Taniguchi, Katsuhiro Maeda et al. report the synthesis of water-soluble stereoregular telechelic poly(phenylacetylene)s by living polymerization in water.

Well-Controlled Living Polymerization of Phenylacetylenes in Water: Synthesis of Water-Soluble Stereoregular Telechelic Poly(phenylacetylene)s.

Well-controlled living polymerization of water-soluble phenylacetylene derivatives in water was achieved for the first time using a multicomponent catalytic system consisting of [Rh(nbd)Cl]2 , an aryl boronic acid, diphenylacetylene having carboxy groups, a tetraalkylammonium hydroxide, and a water-soluble triphenylphosphine. This catalytic system enables a direct synthesis of various water-soluble cis-stereoregular poly(phenylacetylene)s having a narrow molecular weight distribution, the molecular weight of which can be controlled by the initial feed ratio of the monomer to the catalyst. Moreover, the syntheses of water-soluble telechelic poly(phenylacetylene)s having various functional groups at both chain ends as well as a water-soluble block copolymer were achieved.

Well‐Controlled Living Polymerization of Phenylacetylenes in Water: Synthesis of Water‐Soluble Stereoregular Telechelic Poly(phenylacetylene)s

AbstractWell‐controlled living polymerization of water‐soluble phenylacetylene derivatives in water was achieved for the first time using a multicomponent catalytic system consisting of [Rh(nbd)Cl]2, an aryl boronic acid, diphenylacetylene having carboxy groups, a tetraalkylammonium hydroxide, and a water‐soluble triphenylphosphine. This catalytic system enables a direct synthesis of various water‐soluble cis‐stereoregular poly(phenylacetylene)s having a narrow molecular weight distribution, the molecular weight of which can be controlled by the initial feed ratio of the monomer to the catalyst. Moreover, the syntheses of water‐soluble telechelic poly(phenylacetylene)s having various functional groups at both chain ends as well as a water‐soluble block copolymer were achieved.

Polymerization of phenylacetylene catalyzed by rhodium(i) complexes with N-functionalized N-heterocyclic carbene ligands

Rhodium complexes with functionalized NHC ligands catalyze the polymerization of phenylacetylene to give very high molar mass stereoregular polymers. Surprisingly, some chloro-complexes are much more active than related cationic precursors also.

Rhodium(I) Complexes Bearing an Aryl-Substituted 1,3,5-Hexatriene Chain: Catalysts for Living Polymerization of Phenylacetylene and Potential Helical Chirality of 1,3,5-Hexatrienes.

Unique bench-stable rhodium(I) complexes bearing an aryl-substituted 1,3,5-hexatriene chain have been synthesized by reactions of (bicyclo[2.2.1]hepta-2,5-diene)rhodium(I) chloride dimer ([Rh(nbd)Cl]2 ) with aryl boronic acids and diphenylacetylenes in the presence of a 50 % aqueous solution of KOH. X-ray crystallographic analysis of the isolated complexes indicated a square-planar structure stabilized by a strong interaction with one of the aryl groups on the 1,3,5-hexatriene chain, which has a helical structure. The helical chirality of the isolated rhodium complexes was confirmed to be sufficiently stable to be resolved into enantiomers by HPLC on a chiral stationary phase at room temperature. It was confirmed that the isolated rhodium complexes functioned as initiators for living polymerization of phenylacetylene to give cis-stereoregular poly(phenylacetylene) with a well-controlled molecular weight.