A detailed study of the vibrational spectra of the rigid-rod Pt(II)-σ-acetylide polymers, [(PnBU3)2Pt-C≡CC≡CC≡C-] n, [(PnBu3)2Pt-C≡CC≡C-]n, [(PnBu3)2Pt-C≡CC6H 4C≡C-]n, [(PnBU3)2Pt-C≡CC≡CC 6H4C≡CC≡C-]n, and [(AsnBu3)2Pt-C≡CC6H 4C≡C-]n is reported. The backbone chain vibrations in these highly conjugated organometallic polymers can be analyzed by relating them to their centrosymmetric monomeric structures with an approximate C2h or D2h local symmetry. The extent of π-conjugation in the backbone can be monitored from the associated changes in the vibrational frequencies, in particular, the vC≡C modes. In general, the vibrational spectra of the polymers suggest that the backbone is essentially alternating -C≡C- in nature, without any contribution from allene-type structures (=C=C=). The interruption of the acetylenic linkages with phenyl groups reduces the π-conjugation. The near-infrared FT-Raman spectra of the polymers show resonance enhancement of selected vibrations which occur along the direction of the polymer chain, presumably due to coupling with electronic transitions of the backbone. In addition, these polymers exhibit strong and substituent-sensitive fluorescence in their FT-Raman spectra.
|Number of pages||7|
|Publication status||Published - Apr 30 1996|
ASJC Scopus subject areas
- Inorganic Chemistry
- Organic Chemistry