Synthesis, characterisation and optical properties of metal-containing polydiacetylenes

Abstract

Soluble polydiacetylenes (CR–CC–CR′)_n[R = R′=(CH₂)₉O₂CCH₂Ph (2a); R =(CH₂)₉CH₃, R′=(CH₂)₈CO₂CH₂Ph (2b)] have been synthesized and reacted with Co₂(CO)₈ to introduce varying proportions of Co₂(CO)₆ groups, attached as Co₂C₂ tetrahedrane units, at the alkyne bonds of the conjugated ene–yne backbone. These metallated polymers have been characterised by analytical data and by IR, ¹³C[¹H] NMR and UV–VIS spectroscopy. Reactions between polydiacetylenes 2a or 2b and [M₂(CO)₄(η⁵-C₅H₅)₂](M = Mo, W) are also reported. The presence of fast optical non-linearities in these soluble polymeric materials was confirmed by fluorescence lifetime measurements and optical characterisation of the imaginary part of χ⁽³⁾ These studies were conducted on a picosecond timescale to allow electronic contributions to be resolved, and the related lm χ⁽³⁾ values tabulated against metal content and solution concentration.