Preparation of metalated azine complexes of iridium(III)

Abstract

Arylaldazine and acetoneazine complexes [IrCl(η5-C5Me5){κ1-[NC(H)(R2C6H4)]-NC(H)(R2C6H4)}{P(OR1)3}]BPh4 (1, 2) and [IrCl(η5-C5Me5){κ1-[NC(CH3)2]-NC(CH3)2}{P(OR1)3}]BPh4 (3, 4) [R1 = Me (1, 3), Et (2, 4); R2 = H (a), 4-CH3 (b), 2,6-(CH3)2 (f)] were prepared by allowing chloro complexes IrCl2(η5-C5Me5)[P(OR1)3] to react first with AgOTf and then with the appropriate azine. In solution, κ1-complexes 1-4 undergo a metalation reaction, affording chelate κ2-azine derivatives [Ir{κ2-R2C6H3(H)CN-NC(H)(R2C6H4)}(η5-C5Me5){P(OR1)3}]BPh4 (5, 6) and [Ir{κ2-CH2(CH3)CN-NC(CH3)2}(η5-C5Me5){P(OR1)3}]BPh4 (7, 8) [R1 = Me (5, 7), Et (6, 8); R2 = H (a), 4-CH3 (b), 4-CH3O (c); 4-F (d), 4-NO2 (e)]. The complexes were characterised spectroscopically and by X-ray crystal structure determination of [Ir{κ2-C6H4(H)CN-NC(H)(C6H5)}(η5-C5Me5){P(OEt)3}]BPh4 (6a). Most of the κ2-arylazine derivatives showed photoluminescence properties upon excitation with near-UV and violet light, with emission peaks at around 650 nm. The photoluminescence features were rationalised according to DFT calculations.