The utility of suzuki cross-coupling methodology for the the in situ elaboration of bromo-fucntionalised bis-terpyridyl iridium(III)complexes has been explored.The complex [Ir(tpy)(tpy-phi-Br)]~(3+){tpy-phi-Br=4'-(4-bromophenyl)-2,2':6,2"terpyridine}terpyridine}undergoes palladium-catalysed cross-couplign with aryl boronic acids to yield biaryl-substituted compelxes directly.The biphenyl and 4-cyanobiphenyl-substituted products display relatively intense,logn-lived(tau>100mus)yellow emissionin degassed aqueous solution at room temperature,assigned to ~3pi-pi~* state.A 4-aminobiphenyl-substituted analogue displays an additional low energy absorbance band,attributed t an intraligand chrge-transfer(ILCT)excited state,and is scarcely emissive under the same conditions.The iridium(III) complex of 4'-mesityl-terpyridine is also reported.Its emission is much shorter-lived,with a spectral profile resemblign that of unsbubstituted [Ir(tpy)_2]~(3+),confirming the need for the attainment of a roughly coplanar geometry for stablisation of the ~3pi-pi~* excited state.
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