MOLECULAR DESIGN, SYNTHESIS AND STRUCTURE-PROPERTY RELATIONSHIP OF OLIGOTHIOPHENE-DERIVED METALLAYNES

ABSTRACT

A series of conjugated bimetallic complexes and their polymeric analogues containing alkyne-functionalized α-coupled oligothiophenes have been synthesized and characterized. The introduction of transition metal centers, with their large variety of ligand environments and oxidation states, can impart interesting physical, optoelectronic and structural properties on these oligothiophene systems. It was demonstrated that π-conjugation of organometallic alkynyl units into the oligothiophene chain offers intriguing models that possess unique features that are not accessible in the classical organic counterparts. The photophysical, electrochemical and structural properties of these classes of metallaynes have been extensively investigated in terms of the type of metal centers and the number of oligothienyl rings within the bridging ligand. The experimental results have also been correlated to the theoretical data obtained by molecular orbital calculations using density functional theory.

Keywords:

• metallaynes
• oligothiophenes
• cobalt(0)
• platinum(II)
• ferrocenyl
• gold(I)
• mercury(II)
• bithiazoles

ACKNOWLEDGEMENTS

I would like to express my sincere thanks to all the postgraduate students and postdoctoral researchers who were involved in this work. I gratefully acknowledge the financial support from the Research Grants Council of the Hong Kong SAR (HKBU2048/01P) and the Hong Kong Baptist University. Thanks are also due to Drs. K.-W. Cheah and Z. Lin and Prof. P. R. Raithby for various kinds of collaborative efforts that were essential for this work.

Notes

^a GPC against polystyrene calibration.

^b Not reported.

^a In CH₂Cl₂.

^b Φ was not reported. sh = shoulder.

^a Estimated from the absorption edge.

^b Not reported.

^a Intensity of the strongest peak is assigned as unity.

^a In CH₂Cl₂. sh = shoulder.

^a In CH₂Cl₂.

^b Estimated from the absorption edge.

^c All the potential values are with reference to the external ferrocene standard. E _ox = (E _pc + E _pa)/2 for reversible oxidation, and peak potential is reported for irreversible oxidation (in volts). Δ E _p in mV. Scan rate = 100 mV s⁻¹

^d Irreversible wave.

^e Ref. 43 h.