Characterization of the Polymerization Catalyst [(2,5-norbornadiene)Rh{C(Ph)═CPh₂}(PPh₃)] and Identification of the End Structures of Poly(phenylacetylenes) Obtained by Polymerization Using This Catalyst

Abstract

The structures of [(2,5-norbornadiene)Rh{C(Ph)CPh2}(PPh3)] (1) and its reaction product with CH3CO2H were elucidated by 1H, 13C, and 31P NMR spectroscopy, mass spectrometry, and single-crystal X-ray analysis. The presence of two conformational isomers of 1 was verified by NMR spectroscopy, which was well-supported by DFT calculations. Phenylacetylene was polymerized using 1 as a catalyst with [M]0/[Rh] = 10 and quenched with CH3CO2H and CH3CO2D. The incorporation of H and D at the polymer ends was confirmed by MALDI-TOF mass spectrometry and 1H and 1H–13C HSQC NMR spectroscopy. The polymerization degree was calculated to be 11 by 1H NMR spectroscopy, which agreed well with the theoretical value.

Rhodium(I)‐α‐Phenylvinylfluorenyl Complexes: Synthesis, Characterization, and Evaluation as Initiators in the Stereospecific Polymerization of Phenylacetylene

“…It is within this region that signals associated with the remaining 24 aromatic H's appear, i.e. This differs from the Masuda derivative, Rh(nbd)CPh=CPh 2 (PPh 3 ), as reported by Kumazawa et al, [10] in which the 31 P{ 1 H} NMR spectrum presents as a pair of doublets at 26.9 and 26.3 ppm and ambient temperature (measured in d 8 -toluene) with 1 J Rh-P coupling constants of 183 and 187 Hz; this observation was attributed to the presence of two conformational isomers as determined by variable temperature NMR with the two sets of peaks coalescing at 89°C. However, all signals integrate in the expected ratio, confirming the structure.…”

“…While crystal structures of the derivatives Rh(nbd)(CPh= CPh 2 )PPh 3 and Rh(nbd)(CPh=Ph 2 )P(4-ClC 6 H 4 ) 3 have been reported, [7,10] Miyake, Misumi and Masuda noted that they were unable to obtain X-ray quality crystals for the analogous fluorine derivative, Rh(nbd)(CPh=Ph 2 )P(4-FC 6 H 4 ) 3 . [7] In contrast, we were able to readily crystallize each of these new fluorine functionalized Rh I -α-phenylvinylfluorenyl complexes, enabling the solid-state structures to be determined.…”

Polymerizations Mediated by Well‐Defined Rhodium Complexes

“…Although the crystal structure was not reported in this initial disclosure, it was noted that a Rh species was isolated from the ternary mixture and its structure confirmed to be Rh(nbd)(CPh=CPh 2 )PPh 3 on the basis of NMR spectroscopic analysis. The crystal structure of this complex (Figure ) was reported sometime later by Kumazawa et al., who also conducted a detailed examination of the end‐group structure in polyphenylacetylenes prepared with the well‐defined isolated catalyst.…”

Durch definierte Rhodiumkomplexe vermittelte Polymerisationen

“…Die Molekülstruktur dieses Komplexes im Kristall (Abbildung ) wurde einige Zeit später von Kumazawa et al. beschrieben, die auch eine detaillierte Untersuchung zur Endgruppenstruktur von Polyphenylacetylenen, die mit definierten isolierten Katalysatoren hergestellt worden waren, durchführten.…”