Synthesis and solid state characterization of a meridional triphos iridium metallacycle-carbene complex:: [{PhP(CH2CH2PPh2)2} -: Ir(CR=CRCR=CR){=C (CH2)3 O}][BF4] (R = Co2Me)

The five-coordinate iridium metallacycle [(PPh3)(2)Ir(CR=CRCR=CR)(Cl)] (5, R = CO2CH3) and trisphosphine [PhP(CH2CH2PPh2)(2)] are readily converted in refluxing toluene to the fac- and mer-triphos metallacyclopentadiene complexes [{PhP(CH2CH2PPh2)(2)]Ir(CR=CRCR=CR)Cl] (6-fac and 6-mer). Halide abstraction from the facial isomer 6-fac gives the isolable cationic solvate [{PhP(CH2CH2PPh2)(2)}Ir(CR=CR-CR=CR)(ClCH2Cl]BF4 (7, R + CO2CH3) which adopts a mergometry. Reaction of 7 with carbon monoxide generates the mer isomer of [{PhP(CH2CH2PPh2)(2)}Ir(CR=CRCR=CR)(CO)]BF4(8,R = CO2CH3); whereas, reaction of 7 with 3-butyn-1-ol gives the mer-carbene complex [{PPh(CH2CH2PPh2)(2)}Ir(CR=CRCR=CR)(=COCH2CH2CH2)]BF4 (9, R = CO2CH3). A single-crystal X-ray crystallogrphic ananlsis of 9 represent the first solid-state characterization of a meridional [PhP(CH2CH2PPh2)(2)] iridium complex.