Synthesis of new bis(acetylide)-substituted fluorene derivatives and their bimetallic and polymeric complexes

Abstract

A new series of bis(acetylide) organic ligands having fluorene or fluorenone moieties in the backbone, 2,7-di(trimethylsilylethynyl)fluorene ( 1a), 2,7-di(ethynyl)fluorene ( 1b), 2,7-di(trimethylsilylethynyl)fluoren-9-one ( 2a) and 2,7-di(ethynyl)fluoren-9-one ( 2b), has been prepared. Reaction of the diterminal alkynyl fluorene derivatives 1b and 2b with two equivalents of the complex trans-[(Ph)(PEt 3) 2Pt(Cl)] in CH 2Cl 2/ iPr 2NH with catalyic CuI readily affords the diplatinum(II) bis(acetylide) complexes trans-[(Ph)(PEt 3) 2Pt-CC-R 1-CC-Pt(PEt 3) 2(Ph)] (R 1=2,7-fluorenyl 3) and trans-[(Ph)(PEt 3) 2Pt-CC-R 2-CC-Pt(PEt 3) 2(Ph)] (R 2=2,7-fluoren-9-onyl 4) in good yields. Two new rigid-rod organometallic polymers trans-[–Pt(PBu n 3) 2-CC-R 1-CC–]∞ ( 5) and trans-[–Pt(PBu n 3) 2-CC-R 2-CC–]∞ ( 6) have also been prepared in good yields, in a similar manner to their dinuclear complexes 3 and 4, by the CuI-catalysed dehydrohalogenation reaction of trans-[Pt(PBu n 3) 2Cl 2] with one equivalent of 1b or 2b, in an amine solvent, at ambient temperature. Both poly-yne polymers (colourless 5, deep red 6) exhibit good solubility in common organic solvents and readily cast into thin films. The organometallic terminal alkyne complexes trans-[Cl(dppm) 2M-CC-R 2-CCH] (M=Ru 7, Os 8), obtained by treatment of 2b with one equivalent of cis-[M(dppm) 2Cl 2] (M=Ru, Os), based on a NaPF 6/DBU method have been utilised as starting products for access to the homobimetallic trans-[Cl(dppm) 2M-CC-R 2-CC-M(dppm) 2Cl] (M=Ru 9, Os 10) and heterobimetallic trans-[Cl(dppm) 2Ru-CC-R 2-CC-Os(dppm) 2Cl] ( 11) systems by reaction with a suitable choice of cis-M(dppm) 2Cl 2 (M=Ru or Os). All the new compounds have been characterised by analytical and spectroscopic methods, and the single-crystal X-ray structure of 1b has been determined.