Synthesis of Poly(propargyl esters) with Rhodium Catalysts and Their Characterization

Abstract

SummaryPropargyl esters (HC≡CCH 2 OC(=O)R; 1: R = n-C 5 H 11 , 2: R = CH 3 , 3: R = CHBrCH 3 , 4: R = C 6 H 5 , 5: R = C(C 6 H 5 ) 3 ) were polymerized by using (nbd)RhPh 3 ) (nbd = 2,5-norbornadiene) to produce poly(1)-poly(5) with molecular weights in the range of M n = 4,900-40,000. Poly(1), poly(3) and poly(4) were readily soluble in common organic solvents such as toluene, THF and CHCl 3 , and poly(2) showed similar solubility behavior except that it was insoluble in THF. Poly(5) did not dissolve in any organic solvent. Poly(1) was yellow oil, while poly(2)-poly(5) were yellow solids. Poly(1)-poly(4) exhibited UV-vis absorptions in a range of 300-425 nm, which are attributed to the conjugation of the main chain. All the polymers were thermally stable up to 150-200 o C.

Durch definierte Rhodiumkomplexe vermittelte Polymerisationen

“…Beispielsweise wurde von Zhang et al. eine Serie von Polypropargylestern mit dem nbd‐Tetraphenylborat‐Rh‐Katalysator 4 (Abbildung ) hergestellt . Eine Homopolymerisation von Propargylhexanoat mit 4 in THF ergab unter einer Reihe von Bedingungen Polypropargylhexanoat in Ausbeuten von 42–77 %, SEC‐gemessenen M n ‐Werten von 4900–28 000, Ð ‐Werten im Bereich von 1.83 bis 4.70 und einem cis ‐Anteil von 48–88 % mit wenig (wenn überhaupt) klarem Zusammenhang zwischen diesen Merkmalen.…”

“…Zum Beispiel sind Monomere wie Prop‐2‐in‐1‐ylacetat, Prop‐2‐in‐1‐ylbenzoat, Prop‐2‐in‐1‐ylheptanoat und N ‐(Prop‐2‐in‐1‐yl)hexanamid in unkontrollierter Weise mit 1 , dem Phenoxy‐verbrückten Rh‐Derivat 3 und dem zwitterionischen Komplex 4 polymerisiert worden (Abbildung ) . Ähnlich wie bei Phenylacetylenen veräuft die Rh‐vermittelte Polymerisation von Propargylestern und ‐amiden meist in hoch stereoselektiver Weise und liefert Materialien mit hohem cis ‐Anteil, wobei jedoch der endgültige Grad der Stereoregularität vom eingesetzten Katalysator und Lösungsmittel abhängt.…”

Synthesis of Substituted Polyacetylenes Grafted with Polystyrene Chains by the Macromonomer Method and Their Characterization

“…Table 3 summarizes the conditions and results of the copolymerization of macromonomer 1 with comonomer 3 using Rh þ (nbd)(Z 6 -Ph-B À Ph 3 ), which is active for the polymerization of propargyl esters, [19,20] in THF for 24 h [Scheme 1(c)]. THF was chosen as the solvent because it was favorable for the polymerization of propargyl esters in the presence of Rh þ (nbd)(Z 6 -Ph-B À Ph 3 ).…”

“…[2][3][4] For example, helical-substituted polyacetylenes with helical polypeptide side chains were prepared by the copolymerization of the N-propargylamide-terminated peptide-based Summary: A macromonomer (1) consisting of a polystyrene chain and an acetylenic chain end (M n ¼ 2 500, M w =M n ¼ 1. 20) was prepared by atom transfer radical polymerization. Macromonomer 1 was copolymerized with phenylacetylene (2) and propargyl 2-bromopropionate (3) by using Rh catalysts at varying feed ratios from 10 to 50 wt.-% to produce graft copolymers 4 and 5, respectively.…”

Polymerizations Mediated by Well‐Defined Rhodium Complexes

“…For example, monomers such as prop‐2‐yn‐1‐yl acetate, prop‐2‐yn‐1‐yl benzoate, prop‐2‐yn‐1‐yl heptanoate, and N ‐(prop‐2‐yn‐1‐yl)hexanamide have been polymerized in a noncontrolled fashion with 1 , the phenoxy bridged Rh derivative 3 , and the zwitterionic complex 4 (Figure ) . Similar to phenylacetylenes, the Rh‐mediated (co)polymerization of propargyl esters/amides often proceeds in a highly stereoselective manner to yield materials with high cis contents, although the final degree of stereoregularity is dependent on the catalyst and solvent employed.…”